WorldWideScience

Sample records for virus agente causal

  1. [Antibibiotic resistance by nosocomial infections' causal agents].

    Science.gov (United States)

    Salazar-Holguín, Héctor Daniel; Cisneros-Robledo, María Elena

    2016-01-01

    The antibibiotic resistance by nosocomial infections (NI) causal agents constitutes a seriously global problematic that involves the Mexican Institute of Social Security's Regional General Hospital 1 in Chihuahua, Mexico; although with special features that required to be specified and evaluated, in order to concrete an effective therapy. Observational, descriptive and prospective study; by means of active vigilance all along 2014 in order to detect the nosocomial infections, for epidemiologic study, culture and antibiogram to identify its causal agents and antibiotics resistance and sensitivity. Among 13527 hospital discharges, 1079 displayed NI (8 %), standed out: the related on vascular lines, of surgical site, pneumonia and urinal track; they added up two thirds of the total. We carried out culture and antibiogram about 300 of them (27.8 %); identifying 31 bacterian species, mainly seven of those (77.9 %): Escherichia coli, Staphylococcus aureus and epidermidis, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae and Enterobacter cloacae; showing multiresistance to 34 tested antibiotics, except in seven with low or without resistance at all: vancomycin, teicoplanin, linezolid, quinupristin-dalfopristin, piperacilin-tazobactam, amikacin and carbapenems. When we contrasted those results with the recommendations in the clinical practice guides, it aroused several contradictions; so they must be taken with reserves and has to be tested in each hospital, by means of cultures and antibiograms in practically every case of nosocomial infection.

  2. Evidence for Lettuce big-vein associated virus as the causal agent of a syndrome of necrotic rings and spots in lettuce

    NARCIS (Netherlands)

    Verbeek, M.; Dullemans, A.M.; Bekkum, van P.J.; Vlugt, van der R.A.A.

    2013-01-01

    Lettuce big-vein associated virus (LBVaV, genus Varicosavirus) was shown to be responsible for characteristic necrotic symptoms observed in combination with big-vein symptoms in lettuce breeding lines when tested for their susceptibility to lettuce big-vein disease (BVD) using viruliferous Olpidium

  3. Zika Virus Infection and Microcephaly: Evidence for a Causal Link

    Directory of Open Access Journals (Sweden)

    Jin-Na Wang

    2016-10-01

    Full Text Available Zika virus (ZIKV is a flavivirus related to the Dengue, yellow fever and West Nile viruses. Since the explosive outbreaks of ZIKV in Latin America in 2015, a sudden increase in the number of microcephaly cases has been observed in infants of women who were pregnant when they contracted the virus. The severity of this condition raises grave concerns, and extensive studies on the possible link between ZIKV infection and microcephaly have been conducted. There is substantial evidence suggesting that there is a causal link between ZIKV and microcephaly, however, future studies are warranted to solidify this association. To summarize the most recent evidence on this issue and provide perspectives for future studies, we reviewed the literature to identify existing evidence of the causal link between ZIKV infection and microcephaly within research related to the epidemics, laboratory diagnosis, and possible mechanisms.

  4. Zika Virus Infection and Microcephaly: Evidence for a Causal Link.

    Science.gov (United States)

    Wang, Jin-Na; Ling, Feng

    2016-10-20

    Zika virus (ZIKV) is a flavivirus related to the Dengue, yellow fever and West Nile viruses. Since the explosive outbreaks of ZIKV in Latin America in 2015, a sudden increase in the number of microcephaly cases has been observed in infants of women who were pregnant when they contracted the virus. The severity of this condition raises grave concerns, and extensive studies on the possible link between ZIKV infection and microcephaly have been conducted. There is substantial evidence suggesting that there is a causal link between ZIKV and microcephaly, however, future studies are warranted to solidify this association. To summarize the most recent evidence on this issue and provide perspectives for future studies, we reviewed the literature to identify existing evidence of the causal link between ZIKV infection and microcephaly within research related to the epidemics, laboratory diagnosis, and possible mechanisms.

  5. Human Papilloma Viruses and Breast Cancer – Assessment of Causality

    Science.gov (United States)

    Lawson, James Sutherland; Glenn, Wendy K.; Whitaker, Noel James

    2016-01-01

    High risk human papilloma viruses (HPVs) may have a causal role in some breast cancers. Case–control studies, conducted in many different countries, consistently indicate that HPVs are more frequently present in breast cancers as compared to benign breast and normal breast controls (odds ratio 4.02). The assessment of causality of HPVs in breast cancer is difficult because (i) the HPV viral load is extremely low, (ii) HPV infections are common but HPV associated breast cancers are uncommon, and (iii) HPV infections may precede the development of breast and other cancers by years or even decades. Further, HPV oncogenesis can be indirect. Despite these difficulties, the emergence of new evidence has made the assessment of HPV causality, in breast cancer, a practical proposition. With one exception, the evidence meets all the conventional criteria for a causal role of HPVs in breast cancer. The exception is “specificity.” HPVs are ubiquitous, which is the exact opposite of specificity. An additional reservation is that the prevalence of breast cancer is not increased in immunocompromised patients as is the case with respect to HPV-associated cervical cancer. This indicates that HPVs may have an indirect causal influence in breast cancer. Based on the overall evidence, high-risk HPVs may have a causal role in some breast cancers. PMID:27747193

  6. Human Papilloma Viruses and Breast Cancer - Assessment of Causality.

    Science.gov (United States)

    Lawson, James Sutherland; Glenn, Wendy K; Whitaker, Noel James

    2016-01-01

    High risk human papilloma viruses (HPVs) may have a causal role in some breast cancers. Case-control studies, conducted in many different countries, consistently indicate that HPVs are more frequently present in breast cancers as compared to benign breast and normal breast controls (odds ratio 4.02). The assessment of causality of HPVs in breast cancer is difficult because (i) the HPV viral load is extremely low, (ii) HPV infections are common but HPV associated breast cancers are uncommon, and (iii) HPV infections may precede the development of breast and other cancers by years or even decades. Further, HPV oncogenesis can be indirect. Despite these difficulties, the emergence of new evidence has made the assessment of HPV causality, in breast cancer, a practical proposition. With one exception, the evidence meets all the conventional criteria for a causal role of HPVs in breast cancer. The exception is "specificity." HPVs are ubiquitous, which is the exact opposite of specificity. An additional reservation is that the prevalence of breast cancer is not increased in immunocompromised patients as is the case with respect to HPV-associated cervical cancer. This indicates that HPVs may have an indirect causal influence in breast cancer. Based on the overall evidence, high-risk HPVs may have a causal role in some breast cancers.

  7. Viruses: agents of coral disease?

    Science.gov (United States)

    Davy, S K; Burchett, S G; Dale, A L; Davies, P; Davy, J E; Muncke, C; Hoegh-Guldberg, O; Wilson, W H

    2006-03-23

    The potential role of viruses in coral disease has only recently begun to receive attention. Here we describe our attempts to determine whether viruses are present in thermally stressed corals Pavona danai, Acropora formosa and Stylophora pistillata and zoanthids Zoanthus sp., and their zooxanthellae. Heat-shocked P. danai, A. formosa and Zoanthus sp. all produced numerous virus-like particles (VLPs) that were evident in the animal tissue, zooxanthellae and the surrounding seawater; VLPs were also seen around heat-shocked freshly isolated zooxanthellae (FIZ) from P. danai and S. pistillata. The most commonly seen VLPs were tail-less, hexagonal and about 40 to 50 nm in diameter, though a diverse range of other VLP morphotypes (e.g. rounded, rod-shaped, droplet-shaped, filamentous) were also present around corals. When VLPs around heat-shocked FIZ from S. pistillata were added to non-stressed FIZ from this coral, they resulted in cell lysis, suggesting that an infectious agent was present; however, analysis with transmission electron microscopy provided no clear evidence of viral infection. The release of diverse VLPs was again apparent when flow cytometry was used to enumerate release by heat-stressed A. formosa nubbins. Our data support the infection of reef corals by viruses, though we cannot yet determine the precise origin (i.e. coral, zooxanthellae and/or surface microbes) of the VLPs seen. Furthermore, genome sequence data are required to establish the presence of viruses unequivocally.

  8. Moniliophthora roreri, causal agent of cacao frosty pod rot.

    Science.gov (United States)

    Bailey, Bryan A; Evans, Harry C; Phillips-Mora, Wilbert; Ali, Shahin S; Meinhardt, Lyndel W

    2017-12-01

    Taxonomy: Moniliophthora roreri (Cif.) H.C. Evans et al. ; Phylum Basidiomycota; Class Agaricomycetes; Order Agaricales; Family Marasmiaceae; Genus Moniliophthora. Biology: Moniliophthora roreri attacks Theobroma and Herrania species causing frosty pod rot. Theobroma cacao (cacao) is the host of major economic concern. Moniliophthora roreri is a hemibiotroph with a long biotrophic phase (45-90 days). Spore masses, of apparent asexual origin, are produced on the pod surface after initiation of the necrotrophic phase. Spores are spread by wind, rain and human activity. Symptoms of the biotrophic phase can include necrotic flecks and, in some cases, pod malformation, but pods otherwise remain asymptomatic. Relationship to Moniliophthora perniciosa: Moniliophthora roreri and Moniliophthora perniciosa, causal agent of witches' broom disease of cacao, are closely related. Their genomes are similar, including many of the genes they carry which are considered to be important in the disease process. Moniliophthora perniciosa, also a hemibiotroph, has a typical basidiomycete lifestyle and morphology, forming clamp connections and producing mushrooms. Basidiospores infect meristematic tissues including flower cushions, stem tips and pods. Moniliophthora roreri does not form clamp connections or mushrooms and infects pods only. Both pathogens are limited to the Western Hemisphere and are a threat to cacao production around the world. Agronomic importance: Disease losses caused by frosty pod rot can reach 90% and result in field abandonment. Moniliophthora roreri remains in the invasive phase in the Western Hemisphere, not having reached Brazil, some islands within the Caribbean and a few specific regions within otherwise invaded countries. The disease can be managed by a combination of cultural (for example, maintenance of tree height and removal of infected pods) and chemical methods. These methods benefit from regional application, but can be cost prohibitive. Breeding for

  9. Causality and Information Dynamics in Networked Systems with Many Agents

    Science.gov (United States)

    2017-05-11

    algorithms. 6 Future Perspectives Causal graph reconstruction from noisy data is a problem of central importance. In our research we have shown how the idea ...thrust of the research was to develop methods for GCG sparsification using ideas from Tikhonov regularization and ADMM based proximal algorithms...not vary with time. The notion of Granger-causality is captured in the following definition . Definition 2.1 If ξ̂[xi(t) |Ht] < ξ̂[xi(t) |H−jt ] , (2.2

  10. Causality

    Science.gov (United States)

    Pearl, Judea

    2000-03-01

    Written by one of the pre-eminent researchers in the field, this book provides a comprehensive exposition of modern analysis of causation. It shows how causality has grown from a nebulous concept into a mathematical theory with significant applications in the fields of statistics, artificial intelligence, philosophy, cognitive science, and the health and social sciences. Pearl presents a unified account of the probabilistic, manipulative, counterfactual and structural approaches to causation, and devises simple mathematical tools for analyzing the relationships between causal connections, statistical associations, actions and observations. The book will open the way for including causal analysis in the standard curriculum of statistics, artifical intelligence, business, epidemiology, social science and economics. Students in these areas will find natural models, simple identification procedures, and precise mathematical definitions of causal concepts that traditional texts have tended to evade or make unduly complicated. This book will be of interest to professionals and students in a wide variety of fields. Anyone who wishes to elucidate meaningful relationships from data, predict effects of actions and policies, assess explanations of reported events, or form theories of causal understanding and causal speech will find this book stimulating and invaluable.

  11. In vitro evidence for sexual reproduction in Venturia effusa, causal agent of pecan scab

    Science.gov (United States)

    Venturia effusa is the causal agent of pecan scab, the most prevalent disease of pecan in the southeastern US. Venturia effusa is currently only known to reproduce asexually, yet the genetic diversity among populations of pecan scab suggest it is a sexually reproducing pathogen. Analysis of the mati...

  12. Draft Genome Sequence of an Isolate of Colletotrichum fructicola, a Causal Agent of Mango Anthracnose.

    Science.gov (United States)

    Li, Qili; Bu, Junyan; Yu, Zhihe; Tang, Lihua; Huang, Suiping; Guo, Tangxun; Mo, Jianyou; Hsiang, Tom

    2018-02-22

    Here, we present a draft genome sequence of isolate 15060 of Colletotrichum fructicola , a causal agent of mango anthracnose. The final assembly consists of 1,048 scaffolds totaling 56,493,063 bp (G+C content, 53.38%) and 15,180 predicted genes. Copyright © 2018 Li et al.

  13. Antagonistic activity Trichoderma harzianum Rifai on the causal agent of rice blast (Pyricularia grisea Sacc.

    Directory of Open Access Journals (Sweden)

    Ernesto Juniors Pérez Torres

    2017-10-01

    Full Text Available With the objective to evaluate the antagonistic activity of T. harzianum (strain A-34 on the causal agent of rice blast (P. grisea, were developed several in vitro experiments. It was evaluated the biocontrol mechanisms such as competition through mounted the percent inhibition of radial growth of hyphae of P. grisea from 24 to 240 hours and the antagonistic capacity. In addition, was evaluated micoparasitism to inclination the observation of events Microscopy winding, penetration, vacuolization, lysis, and antibiosis by observing 24 hours a confrontation between the hyphae of the phytopathogenic fungus and biological control agent. It was obtained at 120 hours 100 % inhibition of micelial growth of causal agent, what corresponded with the degree 1 of antagonistic capacity (scale and is recorded as a hyperparasitic action on P. grisea. It was evidenced an antibiotic effect of metabolites produced by T. harzianum (strain A-34 to 24 hours of confrontation, where there was time interaction between the hyphae of microorganisms with 14,3 % inhibition, also was evidence the micoparasitism events by penetration, vacuolization and lysis in the cells of phytopathogenic fungus. These results demonstrated the ability of T. harzianum (strain A-34 on causal agent of rice blast (P. grisea.

  14. Morphological and Molecular Identification of the Causal Agent of Anthracnose Disease of Avocado in Kenya.

    Science.gov (United States)

    Kimaru, S K; Monda, E; Cheruiyot, R C; Mbaka, J; Alakonya, A

    2018-01-01

    Anthracnose disease of avocado contributes to a huge loss of avocado fruits due to postharvest rot in Kenya. The causal agent of this disease has not been clear but presumed to be Colletotrichum gloeosporioides as reported in other regions where avocado is grown. The fungus mainly infects fruits causing symptoms such as small blackish spots, "pepper spots," and black spots with raised margin which coalesce as infection progresses. Due to economic losses associated with the disease and emerging information of other species of fungi as causal agents of the disease, this study was aimed at identifying causal agent(s) of the disease. A total of 80 fungal isolates were collected from diseased avocado fruits in Murang'a County, the main avocado growing region in Kenya. Forty-six isolates were morphologically identified as Colletotrichum spp. based on their cultural characteristics, mainly whitish, greyish, and creamish colour and cottony/velvety mycelia on the top side of the culture and greyish cream with concentric zonation on the reverse side. Their spores were straight with rounded end and nonseptate. Thirty-four isolates were identified as Pestalotiopsis spp. based on their cultural characteristics: whitish grey mycelium with black fruiting structure on the upper side and greyish black one on the lower side and septate spores with 3-4 septa and 2 or 3 appendages at one end. Further molecular studies using ITS indicated Colletotrichum gloeosporioides , Colletotrichum boninense , and Pestalotiopsis microspora as the causal agents of anthracnose disease in avocado. However, with this being the first report, there is a need to conduct further studies to establish whether there is coinfection or any interaction thereof.

  15. Morphological and Molecular Identification of the Causal Agent of Anthracnose Disease of Avocado in Kenya

    Directory of Open Access Journals (Sweden)

    S. K. Kimaru

    2018-01-01

    Full Text Available Anthracnose disease of avocado contributes to a huge loss of avocado fruits due to postharvest rot in Kenya. The causal agent of this disease has not been clear but presumed to be Colletotrichum gloeosporioides as reported in other regions where avocado is grown. The fungus mainly infects fruits causing symptoms such as small blackish spots, “pepper spots,” and black spots with raised margin which coalesce as infection progresses. Due to economic losses associated with the disease and emerging information of other species of fungi as causal agents of the disease, this study was aimed at identifying causal agent(s of the disease. A total of 80 fungal isolates were collected from diseased avocado fruits in Murang’a County, the main avocado growing region in Kenya. Forty-six isolates were morphologically identified as Colletotrichum spp. based on their cultural characteristics, mainly whitish, greyish, and creamish colour and cottony/velvety mycelia on the top side of the culture and greyish cream with concentric zonation on the reverse side. Their spores were straight with rounded end and nonseptate. Thirty-four isolates were identified as Pestalotiopsis spp. based on their cultural characteristics: whitish grey mycelium with black fruiting structure on the upper side and greyish black one on the lower side and septate spores with 3-4 septa and 2 or 3 appendages at one end. Further molecular studies using ITS indicated Colletotrichum gloeosporioides, Colletotrichum boninense, and Pestalotiopsis microspora as the causal agents of anthracnose disease in avocado. However, with this being the first report, there is a need to conduct further studies to establish whether there is coinfection or any interaction thereof.

  16. Identification and Control of Cladobotryum spp., Causal Agents of Cobeweb Disease of Cultivated Mushroom

    OpenAIRE

    Ivana Potočnik

    2009-01-01

    Cladobotryum spp. are causal agents of cobweb disease, one of the most serious diseases of cultivated mushroom (Agaricus bisporus (Lange) Imbach) in Serbia and worldwide, which affects product quality and yield. The disease symptoms are: cottony fluffy white or yellowish to pink colonies on mushroom casing, rapid colonization of casing surface, covering of host basidiomata by mycelia, and their decay. Prochloraz-Mn has been officially recommended for mushroom cultivation in EU countries. Howe...

  17. Susceptibility of Haemophilus equigenitalis, the causal agent of contagious equine metritis, to 31 antimicrobial agents.

    Science.gov (United States)

    Sugimoto, C; Isayama, Y; Kashiwazaki, M; Mitani, K

    1981-01-01

    The minimal inhibitory concentrations of 31 antimicrobial agents were determined for 99 isolates of Haemophilus equigenitalis by the agar dilution method. All the isolates showed good susceptibility to 26 antimicrobial agents tests, minimal inhibitory concentrations of which were less than 3.13 micrograms/ml for more than 90% of the isolates. Of these agents, 4 macrolides (erythromycin, oleandomycin, kitasamycin, tylosin), 3 tetracyclines (tetracycline, chlortetracycline, oxytetracycline), 1 peptide (colistin), 1 penicillin (ampicillin) and 1 pleuromutilin (tiamulin) were the most active agents, showing a minimal inhibitory concentration of less than 0.39 micrograms/ml for more than 90% of the isolates. The growth of more than 90% of the isolates was not inhibited by 800 micrograms/ml of streptomycin.

  18. Control of Ralstonia Solanacearum The Causal Agent of Brown Rot in Potato Using Essential Oils

    International Nuclear Information System (INIS)

    Salem, E.A.

    2011-01-01

    Five essential oils, namely peppermint (Mentha piperita L.), caraway (Carium carvum L.), fennel (Foeniculum vulgare Mill.), lemongrass (Cymbopogon citratus Staph.) and thyme (Thymus vulgaris), were used separately against Ralstonia solanacearum; the causal agent of brown rot in potato. The most two effective oils (peppermint and thyme) were used in vitro and in vivo after testing their effects on potato tubers buds germination. Peppermint inhibited buds germination but thyme have no effects on buds germination. In vivo, the control of brown rot using thyme oil in glass house experiment reduced the percentage of brown rot infection to 30.6% and reduced the severity of disease from 5 to 3.

  19. Survival of Fusarium graminearum, the causal agent of Fusarium head blight. A review

    OpenAIRE

    Leplat , Johann; Friberg , Hanna; Abid , Muhammad; Steinberg , Christian

    2012-01-01

    International audience; Wheat is one of the most cultivated crops worldwide. In 2010, 20 % of wheat and durum wheat were cultivated in Europe, 17 % in China and 9 % in Russia and in North America. Wheat yield can be highly decreased by several factors. In particular Fusarium graminearum Schwabe is a worldwide fungal pest impacting wheat production. F. graminearum is the causal agent of Fusarium head blight, root and stem-base rot of cereals. Losses caused by Fusarium head blight in Northern a...

  20. Molecular Detection of Monilinia fructigena as Causal Agent of Brown Rot on Quince

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    Jovana Hrustić

    2012-01-01

    Full Text Available Species of the genus Monilinia are important causal agents of fruit rot on pome and stone fruits in Serbia. The pathogen is very harmful, especially on small properties and cottage plantations where intensive control measures are not applied. Quince is importanthost for the pathogens of this genus. During spring 2010, intensive occurrence of mummified fruits overwintering on branches of the quince was observed. The pathogen was isolated using standard phytopathological methods. Pathogenicity of eight obtained isolates was tested by artificial inoculation of injured apple fruits. Identification was performed according to pathogenic, morphological and ecological properties, and was confirmed by Multiplex polimeraze chain reaction, PCR. All the isolates studied caused brown rot on inoculated apple fruits. The isolates form light yellow colonies with lobate margins,with single-celled, transparent, elliptical or oval conidia in chains, regardless temperature or light presence. Sclerotia are observed in 14 days old cultures. The highest growth rate of most of the isolates is at 27°C and in dark. Based on studied pathogenic, morphological and ecological characteristics, it was found that the Monilinia fructigena is causal agent of brown rot of quince. Using specific primers (MO368-5, MO368-8R, MO368-10R, Laxa-R2for detection of Monilinia species in Multiplex PCR reaction, the expected fragment 402 bp in size was amplified, which confirmed that the studied isolates belonged to the speciesM. fructigena.

  1. Identification and Control of Cladobotryum spp., Causal Agents of Cobeweb Disease of Cultivated Mushroom

    Directory of Open Access Journals (Sweden)

    Ivana Potočnik

    2009-01-01

    Full Text Available Cladobotryum spp. are causal agents of cobweb disease, one of the most serious diseases of cultivated mushroom (Agaricus bisporus (Lange Imbach in Serbia and worldwide, which affects product quality and yield. The disease symptoms are: cottony fluffy white oryellowish to pink colonies on mushroom casing, rapid colonization of casing surface, covering of host basidiomata by mycelia, and their decay. Prochloraz-Mn has been officially recommended for mushroom cultivation in EU countries. However, inefficiency of prochloraz-Mn has been noted at a level of spotting symptoms of cobweb disease. With regard to cases of resistance evolution and a general threat to the environment and human health, special attention should be focused on good programmes of hygiene, and inventing and developing alternative methods of disease control.

  2. Integrated Management of Causal Agents of Postharvest Fruit Rot of Apple

    Directory of Open Access Journals (Sweden)

    Mila Grahovac

    2011-01-01

    Full Text Available One of the major causes of poor quality and fruit loss (during storage and transportare diseases caused by phytopathogenic fungi. Economic losses which are the consequenceof the phytopathogenic fungus activity after harvest exceed the losses in the field.Themost important postharvest fungal pathogens of apple fruits are: Botrytis cinerea Pers. exFr., Penicillium expansum (Lk. Thom., Cryptosporiopsis curvispora (Peck. Grem., Colletotrichumgloeosporioides (Penz. Sacc., Monilinia sp., Gloeosporium album Osterw, Alternaria alternata(Fr. Keissler, Cladosporium herbarium Link., Cylindrocarpon mali (Alles. Wollenw., Stemphyliumbotryosum Wallr. The use of available protection technologies can significantly reducelosses caused by pathogens in storage. The concept of integrated pest management (IPMin apple fruits i.e. sustainable approach in control of causal agents of postharvest fruit rot,using cultural, physical, biological and chemical measures, to minimize economic, healthand risks to consumers and environment, is presented in the paper.

  3. Zika Virus: An Emergent Neuropathological Agent

    Science.gov (United States)

    White, Martyn K.; Wollebo, Hassen S.; Beckham, J. David; Tyler, Kenneth L.; Khalili, Kamel

    2016-01-01

    The emergence of Zika virus in the Americas has followed a pattern that is familiar from earlier epidemics of other viruses, where a new disease is introduced into a human population and then spreads rapidly with important public health consequences. In the case of Zika virus, an accumulating body of recent evidence implicates the virus in the etiology of serious pathologies of the human nervous system, that is, the occurrence of microcephaly in neonates and Guillain–Barré syndrome in adults. Zika virus is an arbovirus (arthropod-borne virus) and a member of the family Flaviviridae, genus Flavivirus. Zika virions are enveloped and icosahedral, and contain a nonsegmented, single-stranded, positive-sense RNA genome, which encodes 3 structural and 7 nonstructural proteins that are expressed as a single polyprotein that undergoes cleavage. Zika genomic RNA replicates in the cytoplasm of infected host cells. Zika virus was first detected in 1947 in the blood of a febrile monkey in Uganda’s Zika Forest and in crushed suspensions of the Aedes mosquito, which is one of the vectors for Zika virus. The virus remained obscure, with a few human cases confined to Africa and Asia. There are two lineages of the Zika virus, African and Asian, with the Asian strain causing outbreaks in Micronesia in 2007 and French Polynesia in 2013–2014. From here, the virus spread to Brazil with the first report of autochthonous Zika transmission in the Americas in March 2015. The rapid advance of the virus in the Americas and its likely association with microcephaly and Guillain–Barré syndrome make Zika an urgent public health concern. PMID:27464346

  4. El consumo de basuco* como agente causal de alteraciones en la encía

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    Lorena Dávila

    2001-08-01

    Full Text Available El abuso en el consumo de drogas, entre ellas al BASUCO, es uno de los grandes problemas de salud pública que tiene que afrontar nuestra comunidad. En este estudio se utilizaron 40 ratas de la cepa Wistar, 20 con carácter experimental y 20 de control utilizando agua destilada durante 16 semanas. Se demostró que existe una relación directa entre el uso de BASUCO y las alteraciones clínicas e histológicas en la encía, de las cuales que el absceso gingival la patología más frecuente (63,2 % de los casos. Tomando en cuenta el incremento del consumo de drogas en nuestra sociedad y los resultados obtenidos, es importante que el odontólgo relacione el uso de las drogas como un agente causal de alteraciones en la encía.The abuse of drugs, and among them of BASUCO, is one of the great public health problems our communioty has to face. 40 Wistar strain rats were used in this study: 20 with an experimental character and 20 as controls. Distilled water was utilized during 16 weeks. It was demonstrated that there is a direct relationship between the use of BASUCO and the clinical and histological alterations of the gingiva, of which the gingival abscess is the most frequent pathology (63.2 % of the cases. Taking into account the increasing consumption of drugs in our society and the results obtained, it is important that the odontologist considers the use of drugs as a causal agent of gingival alterations.

  5. White rot of garlic and onion (Causal agent, Sclerotium cepivorum): A status report from the Pacific Northwest

    Science.gov (United States)

    There is evidence from literature, state department of agriculture documents, and recent diagnoses that Sclerotium cepivorum, causal agent of white rot of garlic and onion, is spreading and/or becoming more established in the Pacific Northwest. Previously documented distributions are summarized, an...

  6. A simple culture method inducing sexual reproduction by Fusarium graminearum, the primary causal agent of Fusarium head blight

    Science.gov (United States)

    The homothallic ascomycete fungus Fusarium graminearum is the primary causal agent of Fusarium head blight (FHB), a devastating disease of wheat and barley worldwide. The fungus undergoes both asexual and sexual stages in its life cycle. The asexual stage produces conidiospores, whereas the sexual s...

  7. Analysis of genetic diversity of Fusarium tupiense, the main causal agent of mango malformation disease in southern Spain

    Science.gov (United States)

    Mango malformation disease (MMD) has become an important global disease affecting this crop. The aim of this study was to identify the main causal agents of MMD in the Axarquía region of southern Spain and determine their genetic diversity. Fusarium mangiferae was previously described in the Axarquí...

  8. Zika Virus and Guillain–Barre Syndrome: Is There Sufficient Evidence for Causality?

    Science.gov (United States)

    Leis, A. Arturo; Stokic, Dobrivoje S.

    2016-01-01

    Worldwide concern over Zika virus causing Guillain–Barre syndrome (GBS) soared after recent reports that Zika-related weakness was due to GBS. A global strategic response plan was initiated with recommendations for at-risk countries to prepare for GBS. This plan has major economic implications, as nations with limited resources struggle to implement costly immunotherapy. Since confirmation of causality is prerequisite to providing specific management recommendations, it is prudent to review data endorsing a GBS diagnosis. We searched PubMed for manuscripts reporting original clinical, laboratory, and electrodiagnostic data on Zika virus and GBS. Five papers met criteria; four case reports and one large case–control study (French Polynesia) that attributed 42 paralysis cases to a motor variant of GBS. Brighton criteria were reportedly used to diagnose GBS, but no differential diagnosis was presented, which violates criteria. GBS was characterized by early onset (median 6 days post-viral syndrome), rapid progression (median 6 days from onset to nadir), and atypical clinical features (52% lacked areflexia, 48% of facial palsies were unilateral). Electrodiagnostic evaluations fell short of guidelines endorsed by American Academy of Neurology. Typical anti-ganglioside antibodies in GBS motor variants were rarely present. We conclude that there is no causal relationship between Zika virus and GBS because data failed to confirm GBS and exclude other causes of paralysis. Focus should be redirected at differential diagnosis, proper use of diagnostic criteria, and electrodiagnosis that follows recommended guidelines. We also call for a moratorium on recommendations for at-risk countries to prepare costly immunotherapies directed at GBS. PMID:27746763

  9. Zika Virus and Guillain-Barre Syndrome: Is There Sufficient Evidence for Causality?

    Directory of Open Access Journals (Sweden)

    A Arturo Leis

    2016-09-01

    Full Text Available Worldwide concern over Zika virus causing Guillain-Barre syndrome (GBS soared after recent reports that Zika-related weakness was due to GBS. A global strategic response plan was initiated with recommendations for at risk countries to prepare for GBS. This plan has major economic implications, as nations with limited resources struggle to implement costly immunotherapy. Since confirmation of causality is prerequisite to providing specific management recommendations, it is prudent to review data endorsing a GBS diagnosis. We searched PubMed for manuscripts reporting original clinical, laboratory, and electrodiagnostic data on Zika virus and GBS. Five papers met criteria; four case reports and one large case-control study (French Polynesia that attributed 42 paralysis cases to a motor variant of GBS. Brighton criteria were reportedly used to diagnose GBS, but no differential diagnosis was presented, which violates criteria. GBS was characterized by early onset (median 6 days post-viral syndrome, rapid progression (median 6 days from onset to nadir, and atypical clinical features (52% lacked areflexia, 48% of facial palsies were unilateral. Electrodiagnostic evaluations fell short of guidelines endorsed by American Academy of Neurology. Typical anti-ganglioside antibodies in GBS motor variants were rarely present. We conclude that there is no causal relationship between Zika virus and GBS because data failed to confirm GBS and exclude other causes of paralysis. Focus should be redirected at differential diagnosis, proper use of diagnostic criteria, and electrodiagnosis that follows recommended guidelines. We also call for a moratorium on recommendations for at risk countries to prepare costly immunotherapies directed at GBS.

  10. Monitoring the infective process of the downy mildew causal agent within micropropagated rose plants

    Directory of Open Access Journals (Sweden)

    Sonia Yamile Gómez

    2012-08-01

    Full Text Available Downy mildew in the rose caused by a species of the Peronospora genus is a very restrictive disease for the Colombian greenhouse rose production. The damage observed in the susceptible varieties of commercial rose include symptoms affect young steams and tiny leaves causing reddish and brown spots and defoliation; leading to 10% production losses. The infective behavior of this pathogen was studied with the aim of increasing the knowledge about the biology of the rose downy mildew. The study of the infective process was performed on the Charlotte variety using micropropagated roses inoculated with suspensions of sporangia. A germinal tube was observed during the germination process, it came from a lateral papilla and reached up to 300 microns in length. During this study, the ability of the pathogen to use vascular sieves as communication systems within the plant was determined. Oogonia and antheridia were also observed inside the epidermal cells, and oospores inside the parenchymal tissue close to xylem vessels. To the best of our knowledge, these sexual structures have not been reported on in Colombia before. This study verifies the ability of the downy mildew causal agent to move through the xylem vessels and produce sexual structures, such as oogonia, antheridia and oospores within those tissues.

  11. Morphological and molecular characterization of the causal agent of downy mildew on Quinoa (Chenopodium quinoa).

    Science.gov (United States)

    Choi, Young-Joon; Danielsen, Solveig; Lübeck, Mette; Hong, Seung-Beom; Delhey, Rolf; Shin, Hyeon-Dong

    2010-05-01

    Downy mildew is an economically important and widespread disease in quinoa (Chenopodium quinoa) growing areas. Although in many studies Peronospora farinosa is most commonly regarded as the causal agent of the disease, identification and classification of the pathogen remain still uncertain due to its taxonomic confusion. Thirty-six Peronospora isolates from quinoa with different geographic origins including Argentina, Bolivia, Denmark, Ecuador, and Peru were morphologically and molecularly compared with Peronospora species from other Chenopodium species. The morphology of three herbarium specimens was similar to that of P. variabilis, which originated from C. album, characterized by flexuous to curved ultimate branchlets and pedicellated conidia. Phylogenetic analysis based on ITS rDNA sequences also placed the quinoa pathogen within the same clade as P. variabilis. Within the ITS rDNA sequences of the quinoa pathogens, two base substitutions were found, which separated the majority of the Danish isolates from isolates from South America, but no sequence difference was found among the isolates from different cultivars of quinoa. The present results indicate that the pathogen responsible for the quinoa downy mildew is identical to Peronospora variabilis and that it should not be lumped with P. farinosa as claimed previously by most studies.

  12. Peptides as Therapeutic Agents for Dengue Virus.

    Science.gov (United States)

    Chew, Miaw-Fang; Poh, Keat-Seong; Poh, Chit-Laa

    2017-01-01

    Dengue is an important global threat caused by dengue virus (DENV) that records an estimated 390 million infections annually. Despite the availability of CYD-TDV as a commercial vaccine, its long-term efficacy against all four dengue virus serotypes remains unsatisfactory. There is therefore an urgent need for the development of antiviral drugs for the treatment of dengue. Peptide was once a neglected choice of medical treatment but it has lately regained interest from the pharmaceutical industry following pioneering advancements in technology. In this review, the design of peptide drugs, antiviral activities and mechanisms of peptides and peptidomimetics (modified peptides) action against dengue virus are discussed. The development of peptides as inhibitors for viral entry, replication and translation is also described, with a focus on the three main targets, namely, the host cell receptors, viral structural proteins and viral non-structural proteins. The antiviral peptides designed based on these approaches may lead to the discovery of novel anti-DENV therapeutics that can treat dengue patients.

  13. The causal direction in the association between respiratory syncytial virus hospitalization and asthma

    DEFF Research Database (Denmark)

    Stensballe, Lone Graff; Simonsen, Jacob Brunbjerg; Thomsen, Simon Francis

    2009-01-01

    BACKGROUND: Earlier studies have reported an increased risk of asthma after respiratory syncytial virus (RSV) hospitalization. Other studies found that asthmatic disposition and propensity to wheeze increase the risk of RSV hospitalization. OBJECTIVE: The current study examined the causal direction......; and asthma is associated with a long-term increased susceptibility for severe RSV disease, suggesting a host factor being responsible for the severe response to RSV infection. This suggests that severe RSV infection and asthma may share a common genetic predisposition and/or environmental exposure....... was increased as much as 6-fold to 8-fold during the first 2 months after RSV hospitalization but was no longer increased 1 year later. Asthma increased the risk of RSV hospitalization by 3-fold, and the risk was not time-dependent. Analyzing these associations on the basis of asthma defined from use of inhaled...

  14. Potential of Pest and Host Phenological Data in the Attribution of Regional Forest Disturbance Detection Maps According to Causal Agent

    Science.gov (United States)

    Spruce, Joseph; Hargrove, William; Norman Steve; Christie, William

    2014-01-01

    Near real time forest disturbance detection maps from MODIS NDVI phenology data have been produced since 2010 for the conterminous U.S., as part of the on-line ForWarn national forest threat early warning system. The latter has been used by the forest health community to identify and track many regional forest disturbances caused by multiple biotic and abiotic damage agents. Attribution of causal agents for detected disturbances has been a goal since project initiation in 2006. Combined with detailed cover type maps, geospatial pest phenology data offer a potential means for narrowing the candidate causal agents responsible for a given biotic disturbance. U.S. Aerial Detection Surveys (ADS) employ such phenology data. Historic ADS products provide general locational data on recent insect-induced forest type specific disturbances that may help in determining candidate causal agents for MODIS-based disturbance maps, especially when combined with other historic geospatial disturbance data (e.g., wildfire burn scars and drought maps). Historic ADS disturbance detection polygons can show severe and extensive regional forest disturbances, though they also can show polygons with sparsely scattered or infrequent disturbances. Examples will be discussed that use various historic disturbance data to help determine potential causes of MODIS-detected regional forest disturbance anomalies.

  15. Effect of Acacia raddiana extracts on Fusarium oxysporum f. sp. albedinis, the causal agent of Bayoud

    Directory of Open Access Journals (Sweden)

    Noureddine BOULENOUAR

    2016-07-01

    Full Text Available In the present study, a medicinal plant from algerian Sahara (South-West of Algeria, Acacia raddiana has been used (leaves, bark to evaluate its extracts (reflux extraction with four solvents: methanol, ethyl acetate, dichloromethane, hexane on Fusarium oxysporum f. sp. albedinis (Foa. The Foa is the causal agent of the most dangerous disease of date palm (Phoenix dactylifera L.. The preliminary evaluation has been realized by agar diffusion technique and virulence test on potato tuber tissues. The extracts that present an inhibition or decrease the relative virulence (RV below 50% undergo phytochemical screening and direct bioautography. The bioautography has been used to localize the antifungal activity on the chromatogram and study the correlation with phytochemical screening data. Among eight extracts, five has been chosen for phytochemical screening and bioautography (2 leaves extracts and 3 bark extracts. Only six tests among 32 (22.58% present a detectable effect. The best effect is related to bark extract with ethyl acetate (inhibition diameter: 18mm, which is a moderate effect. Some extracts show an increase in RV. On the other hand, others decrease the RV. The best effect on RV is presented by hexanic extract of bark (RV=48%. The phytochemical screening highlighted the presence of flavonoids, tannins, coumarins and alkaloids in the studied plant. The direct bioautography has demonstrated no detectable effect. According to realized analyses, we can conclude that this species contains bioactive substances on Foa but need more precise analyses. The reason is simple, in addition to synergy principle in the crude extracts; the quantity of these metabolites is low compared to the detection level.

  16. Draft Genome Sequences of Two Isolates of Colletotrichum lindemuthianum, the Causal Agent of Anthracnose in Common Beans.

    Science.gov (United States)

    de Queiroz, Casley Borges; Correia, Hilberty L Nunes; Menicucci, Renato Pedrozo; Vidigal, Pedro M Pereira; de Queiroz, Marisa Vieira

    2017-05-04

    Colletotrichum lindemuthianum is the causal agent of anthracnose in common beans, one of the main limiting factors of their culture. Here, we report for the first time, to our knowledge, a draft of the complete genome sequences of two isolates belonging to 83.501 and 89 A 2 2-3 of C. lindemutuianum . Copyright © 2017 de Queiroz et al.

  17. Molecular characterization and pathogenicity assays of Colletotrichum acutatum, causal agent for lime anthracnose in Texas

    Science.gov (United States)

    Several distorted Mexican lime [Citrus aurantiifolia (Christm). Swingle] fruit, leaf, and twig samples with lime anthracnose symptoms were collected from three trees in residential areas of Brownsville, Texas. The causal fungal organism, Colletotrichum acutatum J. H. Simmonds was isolated from leave...

  18. ANTAGONISTIC EFFECT OF FOUR FUNGAL ISOLATES TO GANODERMA BONINENSE, THE CAUSAL AGENT OF BASAL STEM ROT OF OIL PALM

    Directory of Open Access Journals (Sweden)

    OKKY SETYAWATI DHARMAPUTRA

    1990-01-01

    Full Text Available Four fungal isolates from soils obtained from three sites of the oil palm plantations in North Sumatra were found antagonistic to Ganoderma boninense, the causal agent of basal stem rot of oil palm. Penicillium citrinum inhibited the growth of the pathogen and formed a zone of inhibition on the agar media. Trichoderma harzianum BIO - 1 as well as BIO - 2 and T. viride not only repressed the growth of the pathogen but also caused lysis of the hyphae, and the colony was totally overgrown by the antagonists.

  19. Hepatitis C Virus Resistance to Carbohydrate-Binding Agents.

    Directory of Open Access Journals (Sweden)

    Laure Izquierdo

    Full Text Available Carbohydrate binding agents (CBAs, including natural lectins, are more and more considered as broad-spectrum antivirals. These molecules are able to directly inhibit many viruses such as Human Immunodeficiency Virus (HIV, Hepatitis C Virus (HCV, Dengue Virus, Ebola Virus or Severe Acute Respiratory Syndrome Coronavirus through binding to envelope protein N-glycans. In the case of HIV, it has been shown that CBAs select for mutant viruses with N-glycosylation site deletions which are more sensitive to neutralizing antibodies. In this study we aimed at evaluating the HCV resistance to CBAs in vitro. HCV was cultivated in the presence of increasing Galanthus nivalis agglutinin (GNA, Cyanovirin-N, Concanavalin-A or Griffithsin concentrations, during more than eight weeks. At the end of lectin exposure, the genome of the isolated strains was sequenced and several potential resistance mutations in the E1E2 envelope glycoproteins were identified. The effect of these mutations on viral fitness as well as on sensitivity to inhibition by lectins, soluble CD81 or the 3/11 neutralizing antibody was assessed. Surprisingly, none of these mutations, alone or in combination, conferred resistance to CBAs. In contrast, we observed that some mutants were more sensitive to 3/11 or CD81-LEL inhibition. Additionally, several mutations were identified in the Core and the non-structural proteins. Thus, our results suggest that in contrast to HIV, HCV resistance to CBAs is not directly conferred by mutations in the envelope protein genes but could occur through an indirect mechanism involving mutations in other viral proteins. Further investigations are needed to completely elucidate the underlying mechanisms.

  20. The Born Rule and Free Will: why Libertarian Agent-Causal Free Will is not "antiscientific"

    Science.gov (United States)

    Kastner, Ruth E.

    In the libertarian "agent causation" view of free will, free choices are attributable only to the choosing agent, as opposed to a specific cause or causes outside the agent. An often-repeated claim in the philosophical literature on free will is that agent causation necessarily implies lawlessness, and is therefore "antiscientific." That claim is critiqued and it is argued, on the contrary, that the volitional powers of a free agent need not be viewed as anomic, specifically with regard to the quantum statistical law (the Born Rule). Assumptions about the role and nature of causation, taken as bearing on volitional agency, are examined and found inadequate to the task. Finally, it is suggested that quantum theory may constitute precisely the sort of theory required for a nomic grounding of libertarian free will.

  1. Cutaneous Papillomaviruses and Non-melanoma Skin Cancer: Causal Agents or Innocent Bystanders?

    Science.gov (United States)

    Hasche, Daniel; Vinzón, Sabrina E; Rösl, Frank

    2018-01-01

    There is still controversy in the scientific field about whether certain types of cutaneous human papillomaviruses (HPVs) are causally involved in the development of non-melanoma skin cancer (NMSC). Deciphering the etiological role of cutaneous HPVs requires - besides tissue culture systems - appropriate preclinical models to match the obtained results with clinical data from affected patients. Clear scientific evidence about the etiology and underlying mechanisms involved in NMSC development is fundamental to provide reasonable arguments for public health institutions to classify at least certain cutaneous HPVs as group 1 carcinogens. This in turn would have implications on fundraising institutions and health care decision makers to force - similarly as for anogenital cancer - the implementation of a broad vaccination program against "high-risk" cutaneous HPVs to prevent NMSC as the most frequent cancer worldwide. Precise knowledge of the multi-step progression from normal cells to cancer is a prerequisite to understand the functional and clinical impact of cofactors that affect the individual outcome and the personalized treatment of a disease. This overview summarizes not only recent arguments that favor the acceptance of a viral etiology in NMSC development but also reflects aspects of causality in medicine, the use of empirically meaningful model systems and strategies for prevention.

  2. Cutaneous Papillomaviruses and Non-melanoma Skin Cancer: Causal Agents or Innocent Bystanders?

    Directory of Open Access Journals (Sweden)

    Daniel Hasche

    2018-05-01

    Full Text Available There is still controversy in the scientific field about whether certain types of cutaneous human papillomaviruses (HPVs are causally involved in the development of non-melanoma skin cancer (NMSC. Deciphering the etiological role of cutaneous HPVs requires – besides tissue culture systems – appropriate preclinical models to match the obtained results with clinical data from affected patients. Clear scientific evidence about the etiology and underlying mechanisms involved in NMSC development is fundamental to provide reasonable arguments for public health institutions to classify at least certain cutaneous HPVs as group 1 carcinogens. This in turn would have implications on fundraising institutions and health care decision makers to force – similarly as for anogenital cancer – the implementation of a broad vaccination program against “high-risk” cutaneous HPVs to prevent NMSC as the most frequent cancer worldwide. Precise knowledge of the multi-step progression from normal cells to cancer is a prerequisite to understand the functional and clinical impact of cofactors that affect the individual outcome and the personalized treatment of a disease. This overview summarizes not only recent arguments that favor the acceptance of a viral etiology in NMSC development but also reflects aspects of causality in medicine, the use of empirically meaningful model systems and strategies for prevention.

  3. First Isolation and Molecular Characterization of Bacteriophages Infecting Acidovorax citrulli, the Causal Agent of Bacterial Fruit Blotch

    Directory of Open Access Journals (Sweden)

    Aryan Rahimi-Midani

    2018-02-01

    Full Text Available Bacteriophages of Acidovorax citrulli, the causal agent of bacterial fruit blotch, were isolated from 39 watermelon, pumpkin, and cucumber leaf samples collected from various regions of Korea and tested against 18 A. citrulli strains. Among the six phages isolated, ACP17 forms the largest plaque, and exhibits the morphology of phages in the Myoviridae family with a head diameter of 100 ± 5 nm and tail length of 150 ± 5 nm. ACP17 has eclipse and latent periods of 25 ± 5 min and 50 ± 5 min, respectively, and a burst size of 120. The genome of ACP17 is 156,281 base pairs with a G + C content of 58.7%, 263 open reading frames, and 4 transfer RNA genes. Blast search and phylogenetic analysis of the major capsid protein showed that ACP17 has limited homology to two Stentrophomonas phages, suggesting that ACP17 is a new type of Myoviridae isolated from A. citrulli.

  4. Indole-3-acetic acid biosynthesis in Fusarium delphinoides strain GPK, a causal agent of Wilt in Chickpea.

    Science.gov (United States)

    Kulkarni, Guruprasad B; Sanjeevkumar, S; Kirankumar, B; Santoshkumar, M; Karegoudar, T B

    2013-02-01

    Fusarium delphinoides (Ascomycota; Nectriaceae) is an indole-3-acetic acid (IAA) producing plant pathogen and a causal agent of wilt in chickpea. The IAA biosynthetic pathway in F. delphinoides strain GPK (FDG) was examined by analyzing metabolic intermediates and by feeding experiments. Gas chromatograph (GC) analysis of FDG culture filtrates showed the presence of metabolic intermediates of indole-3-pyruvic acid (IPyA), indole-3-acetamide (IAM), and tryptamine (TRA) pathways. The different IAA biosynthetic pathways were further confirmed by identifying the presence of different enzymes of these pathways. Substrate specificity study of aromatic amino acid aminotransferase revealed that the enzyme is highly specific for tryptophan (Trp) and α-ketoglutarate (α-kg) as amino group donor and acceptor, respectively. Furthermore, the concentration-dependent effect of exogenous IAA on fungal growth was established. Low concentration of exogenous IAA increases the fungal growth and at high concentration it decreases the growth of FDG.

  5. Improved Diagnoses and Quantification of Fusarium virguliforme, Causal Agent of Soybean Sudden Death Syndrome.

    Science.gov (United States)

    Wang, Jie; Jacobs, Janette L; Byrne, Jan M; Chilvers, Martin I

    2015-03-01

    Fusarium virguliforme (syn. F. solani f. sp. glycines) is the primary causal pathogen responsible for soybean sudden death syndrome (SDS) in North America. Diagnosis of SDS is difficult because symptoms can be inconsistent or similar to several soybean diseases and disorders. Additionally, quantification and identification of F. virguliforme by traditional dilution plating of soil or ground plant tissue is problematic due to the slow growth rate and plastic morphology of F. virguliforme. Although several real-time quantitative polymerase chain reaction (qPCR)-based assays have been developed for F. virguliforme, the performance of those assays does not allow for accurate quantification of F. virguliforme due to the reclassification of the F. solani species complex. In this study, we developed a TaqMan qPCR assay based on the ribosomal DNA (rDNA) intergenic spacer (IGS) region of F. virguliforme. Specificity of the assay was demonstrated by challenging it with genomic DNA of closely related Fusarium spp. and commonly encountered soilborne fungal pathogens. The detection limit of this assay was determined to be 100 fg of pure F. virguliforme genomic DNA or 100 macroconidia in 0.5 g of soil. An exogenous control was multiplexed with the assay to evaluate for PCR inhibition. Target locus copy number variation had minimal impact, with a range of rDNA copy number from 138 to 233 copies per haploid genome, resulting in a minor variation of up to 0.76 cycle threshold values between strains. The qPCR assay is transferable across platforms, as validated on the primary real-time PCR platform used in the Northcentral region of the National Plant Diagnostic Network. A conventional PCR assay for F. virguliforme detection was also developed and validated for use in situations where qPCR is not possible.

  6. 9 CFR 113.55 - Detection of extraneous agents in Master Seed Virus.

    Science.gov (United States)

    2010-01-01

    ... Master Seed Virus. 113.55 Section 113.55 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Ingredient Requirements § 113.55 Detection of extraneous agents in Master Seed Virus...

  7. Virus como inductores de neoplasias cutáneas Viruses as agents inducing cutaneous neoplasms

    Directory of Open Access Journals (Sweden)

    Francisco Bravo Puccio

    2013-03-01

    Full Text Available El rol oncogénico de los virus en las neoplasias cutáneas es conocido por el hombre desde hace más de un siglo, cuando se atribuía el origen de la verruga vulgar al virus papiloma humano (VPH. En la actualidad, las neoplasias inducidas por virus pueden agruparse en tumores sólidos y procesos linfoproliferativos. Destacan entre los primeros el VPH, del cual ahora conocemos numerosos serotipos, cada uno vinculado a una neoplasia específica, el herpesvirus humano tipo 8 que produce el sarcoma de Kaposi y el poliomavirus vinculado al carcinoma de Merkel. Entre los procesos linfoproliferativos debemos mencionar al virus linfotrópico de células T humanas tipo 1 (HTLV-1 responsable de los linfomas de células T, en los cuales el compromiso cutáneo es inespecífico, con un amplio espectro de presentaciones clínicas y, que por consiguiente, plantean un reto para el diagnóstico diferencial. En este grupo también se encuentra el virus Epstein Barr vinculado a los linfomas nasales de Células NK/T y a los linfomas tipo Hidroa, de reciente descripción. En esta era en la que lo genético y lo molecular priman en las investigaciones en cáncer, no podemos dejar de lado el concepto de neoplasia como resultado de la infección por un agente viral, lo que abre una nueva veta de posibilidades de tratamiento anticanceroso basado en medicamentos antiviralesThe oncogenic role of viruses in cutaneous neoplasms has been known by humankind for more than a century, when the origin of the common wart, or verruca vulgaris, was attributed to the human papilloma virus (HPV. Currently, virus-induced cutaneous neoplasms may be grouped into solid tumors and lymphoproliferative disorders. HPV, from which various serotypes are now known, each being linked to a specific neoplasm, the human herpes virus type 8 producing Kaposi sarcoma, and the Merkel cell polyomavirus, highlight among the first group. Regarding the lymphoproliferative disorders, we should mention the

  8. Isolation and characterization of the mating type locus of Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana

    NARCIS (Netherlands)

    Conde, L.; Waalwijk, C.; Canto-Canché, B.B.; Kema, G.H.J.; Crous, P.W.; James, A.C.; Abeln, E.C.A.

    2007-01-01

    Idiomorphs mat1-1 and mat1-2 from Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana, were isolated. Degenerate oligos were used to amplify the HMG box of the mat1-2 idiomorph from M. fijiensis, showing homology with the HMG box of Mycosphaerella graminicola. Using a

  9. Variable number of tandem repeat markers in the genome sequence of Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana (Musa spp)

    NARCIS (Netherlands)

    Garcia, S.A.L.; Lee, van der T.A.J.; Ferreira, C.F.; Lintel Hekkert, te B.; Zapater, M.F.; Goodwin, S.B.; Guzmán, M.; Kema, G.H.J.; Souza, M.T.

    2010-01-01

    ABSTRACT. We searched the genome of Mycosphaerella fijiensis for molecular markers that would allow population genetics analysis of this plant pathogen. M. fijiensis, the causal agent of banana leaf streak disease, also known as black Sigatoka, is the most devastating pathogen attacking bananas

  10. Development of VNTR Markers to Assess Genetic Diversity of Mycosphaerella Fijiensis, the Causal Agent of Black Leaf Streak Disease in Bananas (Musa spp.)

    Science.gov (United States)

    Mycosphaerella fijiensis is the causal agent of black leaf streak (BLS) disease in bananas. This pathogen threatens global banana production as the main export cultivars are highly susceptible. As a consequence, commercial banana plantations must be protected chemically with fungicides; up to 40 app...

  11. Variable Number of Tandem Repeat Markers in the Genome Sequence of Mycosphaerella Fijiensis, the Causal Agent of Black Leaf Streak Disease of Banana (Musa spp.)

    Science.gov (United States)

    Mycosphaerella fijiensis, the causal agent of banana leaf streak disease (commonly known as black Sigatoka), is the most devastating pathogen attacking bananas (Musa spp). Recently the whole genome sequence of M. fijiensis became available. This sequence was screened for the presence of Variable Num...

  12. The Prevalence of Trypanosoma cruzi, the Causal Agent of Chagas Disease, in Texas Rodent Populations.

    Science.gov (United States)

    Aleman, Adriana; Guerra, Trina; Maikis, Troy J; Milholland, Matthew T; Castro-Arellano, Ivan; Forstner, Michael R J; Hahn, Dittmar

    2017-03-01

    Rodent species were assessed as potential hosts of Trypanosoma cruzi, the etiologic agent of Chagas disease, from five sites throughout Texas in sylvan and disturbed habitats. A total of 592 rodents were captured, resulting in a wide taxonomic representation of 11 genera and 15 species. Heart samples of 543 individuals were successfully analyzed by SybrGreen-based quantitative PCR (qPCR) targeting a 166 bp fragment of satellite DNA of T. cruzi. Eight rodents representing six species from six genera and two families were infected with T. cruzi. This is the first report of T. cruzi in the pygmy mouse (Baiomys taylori) and the white-footed mouse (Peromyscus leucopus) for the USA. All infected rodents were from the southernmost site (Las Palomas Wildlife Management Area). No differences in pathogen prevalence existed between disturbed habitats (5 of 131 tested; 3.8%) and sylvan habitats (3 of 40 tested; 7.5%). Most positives (n = 6, 16% prevalence) were detected in late winter with single positives in both spring (3% prevalence) and fall (1% prevalence). Additionally, 30 Triatoma insects were collected opportunistically from sites in central Texas. Fifty percent of these insects, i.e., 13 T. gerstaeckeri (68%), and two T. lecticularia (100%) were positive for T. cruzi. Comparative sequence analyses of 18S rRNA of samples provided identical results with respect to detection of the presence or absence of T. cruzi and assigned T. cruzi from rodents collected in late winter to lineage TcI. T. cruzi from Triatoma sp. and rodents from subsequent collections in spring and fall were different, however, and could not be assigned to other lineages with certainty.

  13. Parainfluenza Virus Infection Sensitizes Cancer Cells to DNA-Damaging Agents: Implications for Oncolytic Virus Therapy.

    Science.gov (United States)

    Fox, Candace R; Parks, Griffith D

    2018-04-01

    A parainfluenza virus 5 (PIV5) with mutations in the P/V gene (P/V-CPI - ) is restricted for spread in normal cells but not in cancer cells in vitro and is effective at reducing tumor burdens in mouse model systems. Here we show that P/V-CPI - infection of HEp-2 human laryngeal cancer cells results in the majority of the cells dying, but unexpectedly, over time, there is an emergence of a population of cells that survive as P/V-CPI - persistently infected (PI) cells. P/V-CPI - PI cells had elevated levels of basal caspase activation, and viability was highly dependent on the activity of cellular inhibitor-of-apoptosis proteins (IAPs) such as Survivin and XIAP. In challenge experiments with external inducers of apoptosis, PI cells were more sensitive to cisplatin-induced DNA damage and cell death. This increased cisplatin sensitivity correlated with defects in DNA damage signaling pathways such as phosphorylation of Chk1 and translocation of damage-specific DNA binding protein 1 (DDB1) to the nucleus. Cisplatin-induced killing of PI cells was sensitive to the inhibition of wild-type (WT) p53-inducible protein 1 (WIP1), a phosphatase which acts to terminate DNA damage signaling pathways. A similar sensitivity to cisplatin was seen with cells during acute infection with P/V-CPI - as well as during acute infections with WT PIV5 and the related virus human parainfluenza virus type 2 (hPIV2). Our results have general implications for the design of safer paramyxovirus-based vectors that cannot establish PI as well as the potential for combining chemotherapy with oncolytic RNA virus vectors. IMPORTANCE There is intense interest in developing oncolytic viral vectors with increased potency against cancer cells, particularly those cancer cells that have gained resistance to chemotherapies. We have found that infection with cytoplasmically replicating parainfluenza virus can result in increases in the killing of cancer cells by agents that induce DNA damage, and this is linked

  14. Dieback of rose caused by Acremonium sclerotigenum as a new causal agent of rose dieback in Iran

    International Nuclear Information System (INIS)

    Mirtalebi, M.; Banihashemi, Z.; Sabahi, F.; Mafakheri, H.

    2016-01-01

    Severe dieback of rose has been recently observed in several rose greenhouses in Fars province of Iran. During 2014 and 2015, stems of rose plants showing yellow to brown discoloration and dieback were collected from rose greenhouses. Coniothyrium fuckelii, Botrytis cinerea and Acremonium were subsequently isolated from the margin between healthy and symptomatic tissue. B. cinerea and C. fuckelii isolates were similar to those previously reported for dieback of rose worldwide. Morphological and cultural characters along with molecular analysis based on partial sequences of the internal transcribed spacer (ITS) region of the ribosomal RNA genome allowed confirming the affiliation of the Acremonium isolates, corresponding to A. sclerotigenum as a new causal agent of rose dieback. To determine its pathogenicity on rose, Koch's postulates were fulfilled by stem inoculation of nine rose cultivars under greenhouse conditions. While A. sclerotigenum is considered as a soil-born pathogen, and produces sclerotia that are resistant to adverse conditions enables the fungus to survive extended period in soil, propagule trapping in our study revealed that conidia can become airborn, imply that an aerial phase, forms an important component of the disease cycle.

  15. Presencia de Blastocystis Hominis como agente causal de enfermedades gatrointestinales en la comuna 7 (Gaira del Distrito de Santa Marta

    Directory of Open Access Journals (Sweden)

    Sonja Liliana Lozano Socarras

    2013-10-01

    Full Text Available La Blastocystis hominis es un protozoo que causa cuadros diarreicos. Es altamente prevalente en poblaciones que no cuentan con servicios adecuados de higiene, alcantarillado y salud pública. La infección con Blastocystis hominis frecuentemente concomita con otros enteropatógenos de reconocida patogenicidad, además se ha reportado como parásito oportunista en pacientes con VIII SIDA. El objetivo del presente estudio es determinar la presencia de Blastocystis hominis en pacientes de consulta externa con síntomas asociados a enfermedades gastrointestinales, en la comuna 7 del distrito de Santa Marta, Colombia, durante el mes de Enero a Diciembre de 2004. El método de diagnóstico utilizado fue examen coproparasitológico seriado y el número de pacientes analiza-dos fue de 291. Los resultados muestran una alta presencia de Blastocystis hominken pacientes con enfermedad diarreica residentes en Gaira. Un alto porcentaje de la población parasitada (62,6% presento como único agente causal de la enfermedad diarreica al Blastocystis hominis lo que sugiere la presencia de otras enfermedades que pueden involucrar un compromiso inmunológico, el efecto será una respuesta inmune débil contra el parásito.

  16. Morphological and molecular identification of Fusarium tricinctum and Fusarium acuminatum as causal agents of garlic bulbs rot in Serbia

    Directory of Open Access Journals (Sweden)

    Ignjatov Maja V.

    2017-01-01

    Full Text Available Garlic (Allium sativum L. is considered to be one of the oldest crops in the world. During 2016, infected garlic bulbs occurred in storages on several localities of the Province of Vojvodina. Symptomatic cloves showed typical rot symptoms such as softened and spongy areas covered with white fungal growth with deep lesions formed on the cloves which became dry over time. A total of 36 isolates of Fusarium species were obtained from diseased cloves of garlic. Colony morphology and microscopic properties of isolated Fusarium species were recorded from the cultures grown on PDA and CLA, respectively. Identification of two chosen isolates was performed by sequencing the EF-1α gene. The TEF sequence of isolate JBL12 showed 100% similarity with several F. tricinctum sequences and sequence of JBL539 showed 99% identity with several F. acuminatum sequences and they were deposited in the NCBI GenBank. Based on the results of the morphological and molecular identification, isolates JBL12 and JBL539 were identified as F. tricinctum and F. acuminatum, respectively, as new causal agents of garlic bulbs rot in Serbia. Specific primers were designed for the PCR identification of the F. tricinctum. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR31030

  17. Dieback of rose caused by Acremonium sclerotigenum as a new causal agent of rose dieback in Iran

    Energy Technology Data Exchange (ETDEWEB)

    Mirtalebi, M.; Banihashemi, Z.; Sabahi, F.; Mafakheri, H.

    2016-07-01

    Severe dieback of rose has been recently observed in several rose greenhouses in Fars province of Iran. During 2014 and 2015, stems of rose plants showing yellow to brown discoloration and dieback were collected from rose greenhouses. Coniothyrium fuckelii, Botrytis cinerea and Acremonium were subsequently isolated from the margin between healthy and symptomatic tissue. B. cinerea and C. fuckelii isolates were similar to those previously reported for dieback of rose worldwide. Morphological and cultural characters along with molecular analysis based on partial sequences of the internal transcribed spacer (ITS) region of the ribosomal RNA genome allowed confirming the affiliation of the Acremonium isolates, corresponding to A. sclerotigenum as a new causal agent of rose dieback. To determine its pathogenicity on rose, Koch's postulates were fulfilled by stem inoculation of nine rose cultivars under greenhouse conditions. While A. sclerotigenum is considered as a soil-born pathogen, and produces sclerotia that are resistant to adverse conditions enables the fungus to survive extended period in soil, propagule trapping in our study revealed that conidia can become airborn, imply that an aerial phase, forms an important component of the disease cycle.

  18. Development of Nested-PCR Assay to Detect Acidovorax citrulli, a Causal Agent of Bacterial Fruit Blotch at Cucurbitaceae

    Directory of Open Access Journals (Sweden)

    Young-Tak Kim

    2015-06-01

    Full Text Available The specific and sensitive nested-PCR method to detect Acidovorax citrulli, a causal agent of bacterial fruit blotch on cucurbitaceae, was developed. PCR primers were designed from the draft genome sequence which was obtained with the Next Generation Sequencing of A. citrulli KACC10651, and the nested-PCR primer set (Ac-ORF 21F/Ac-ORF 21R were selected by checking of specificity to A. citrulli with PCR assays. The selected nested-PCR primer amplified the 140 bp DNA only from A. citrulli strains, and detection sensitivity of the nested PCR increased 10,000 times of 1st PCR detection limit (10 ng genomic DNA/PCR. The nested PCR detected A. citrulli from the all samples of seed surface wash (external seed detection of the artificially inoculated watermelon seeds with 101 cfu/ml and above population of A. citrulli while the nested PCR could not detected A. citrulli from the mashed seed suspension (internal seed detection of the all artificially inoculated watermelon seeds. When the naturally infested watermelon seeds (10% seed infested rate with grow-out test used, the nested PCR detected A. citrulli from 2 seed samples out of 10 replication samples externally and 5 seed samples out of 10 replication samples internally. We believe that the nested-PCR developed in this study will be useful method to detect A. citrulli from the Cucurbitaceae seeds.

  19. Xanthomonas oryzae pv oryzae the Causal Agent of Bacterial Leaf Blight of rice: Isolation, Characterization, and Study of Transposon Mutagenesis

    Directory of Open Access Journals (Sweden)

    Abdjad Asih Nawangsih

    2011-04-01

    Full Text Available Xanthomonas oryzae pv oryzae the Causal Agent of Bacterial Leaf Blight of rice: Isolation, Characterization, and Study of Transposon Mutagenesis. X. oryzae pv. oryzae (Xoo causes bacterial leaf blight (BLB of rice (Oryza sativa L., a major disease that constrains production of the staple crop in many countries of the world. Identification of X. oryzae pv. oryzae (Xoo was conducted based on the disease symptoms, pathogenicity, morphological, physiological, and genetic characteristics of bacterial cultures isolated from the infected plants. Fifty bacterial isolates predicted as Xoo have been successfully isolated. They are aerobic, rod shaped, and Gram negative bacteria. The isolates were evaluated for their hypersensitivity in tobacco and pathogenicity in rice plant. Fifty isolates induced hypersensitive reaction in tobacco and showed pathogenicity symptom in rice in different length. Based on physiological test, hypersensitivity and pathogenicity reactions, three bacterial isolates strongly predicted as Xoo, i.e. STG21, STG42, and STG46, were non indole formation, non pigment fluorescent, hydrolyzed casein, catalase activity positive, but negative oxidase. Partial sequencing of 16S rRNA genes of STG21 and STG42 showed 80% and 82% homology with X. oryzae, respectively, while STG46 showed 84% homology with X. campestris. Mini-Tn5 transposon mutagenesis of STG21 generated one of the mutants (M5 lossed it’s ability to induce hypersensitive reaction in tobacco plant and deficient in pathogenicity on rice. The lesion length of rice leaf caused by the mutant M5 decreased up to 80%.

  20. Podredumbres basales de Gypsophila paniculata (Caryophyllaceae: Agentes causales y su patogenicidad potencial sobre Dianthus caryophyllus (Caryophyllaceae Basal rots of Gypsophila paniculata (Caryophyllaceae: Causal agents and its potential pathogenicity on Dianthus caryophyllus (Caryophyllaceae

    Directory of Open Access Journals (Sweden)

    Silvia María Wolcan

    Full Text Available Los objetivos del trabajo fueron identificar a los agentes causales de las podredumbres basales de Gypsophila paniculata en la Argentina y probar su posible patogenicidad sobre Dianthus caryophyllus . A partir de plantas con síntomas de «podredumbre de la corona» (la más importante se aislaron en orden decreciente: Fusarium solani , F. oxysporum , Phytophthora nicotianae , Rhizoctonia solani , F. graminearum , F. verticillioides, F. equiseti y Pythium sp. y de plantas con «podredumbre basal del tallo» F. graminearum , F. oxysporum y F. solani . Con distintas cepas de cada hongo se hicieron pruebas de patogenicidad mediante la infestación del suelo y el depósito de inóculo en heridas producidas en los tallos. En la «podredumbre de la corona» fueron patógenos P. nicotianae causando decaimiento rápido de la parte aérea y podredumbre blanda de la corona y R. solani causando una pudrición más lenta y tejidos desintegrados. F. graminearum fue el patógeno de la «podredumbre basal del tallo» de gipsofila, que se describe por primera vez en este hospedante , comprobando que el hongo penetra sólo por heridas del tallo. En condiciones de inoculación se confirmó que algunas cepas de R. solani y de F. graminearum aisladas de gipsofila pueden ser patógenas de clavel mientras que sólo algunas de P. nicotianae resultaron patógenas débiles.The aims of the paper were to determine the causal agents of basal rots of Gypsophila paniculata in Argentina, and to evaluate its possible pathogenicity on Dianthus caryophyllus. Fusarium solani, F. oxysporum , Phytophthora nicotianae , Rhizoctonia solani , F. graminearum , F. verticilloides, F. equiseti and Pythium sp. were isolated in decreasing order from plants with symptoms of «crown rot» (the major basal rot. F. graminearum , F. oxysporum and F. solani were isolated from plants with «basal stem rot». Inoculations of gypsophila were performed by soil infestation and by placing inoculum on

  1. ITS-rDNA phylogeny of Colletotrichum spp. causal agent of apple Glomerella leaf spot Filogenia por ITS-rDNA de Colletotrichum spp., agente causal da mancha foliar da Gala em macieira

    Directory of Open Access Journals (Sweden)

    Diorvania Ribeiro Giaretta

    2010-04-01

    Full Text Available Several diseases have affected apple production, among them there is Glomerella leaf spot (GLS caused by Colletotrichum spp. The first report of this disease in apple was in plants nearby citrus orchards in São Paulo State, Brazil. The origin of this disease is still not clear, and studies based on the molecular phylogeny could relate the organisms evolutionarily and characterize possible mechanisms of divergent evolution. The amplification of 5.8S-ITS (Internal Transcribed Spacer of rDNA of 51 pathogenic Colletotrichum spp. isolates from apples, pineapple guava and citrus produced one fragment of approximately 600 bases pairs (bp for all the isolates analyzed. The amplified fragments were cleaved with restriction enzymes, and fragments from 90 to 500bp were obtained. The sequencing of this region allowed the generation of a phylogenetic tree, regardless of their hosts, and 5 isolated groups were obtained. From the "in silico" comparison, it was possible to verify a variation from 93 to 100% of similarity between the sequences studied and the Genbank data base. The causal agent of GLS is nearly related (clustered to isolates of pineapple guava and to the citrus isolates used as control.A produção de maçã vem sendo comprometida pela ocorrência de muitas doenças, entre as quais se destaca a Mancha Foliar de Glomerella (MFG, causada por Colletotrichum spp. O primeiro relato dessa doença em maçã foi registrado em plantas próximas a pomares de citrus no Estado de São Paulo, Brasil. A origem da MFG ainda não está bem clara, e estudos baseados na filogenia permitirão relacionar o organismo evolutivamente, possibilitando caracterizar possíveis mecanismos divergentes de evolução. A amplificação da região 5.8S-ITS (espaçador interno transcrito do rDNA de 51 isolados de Colletotrichum patogênicos em de maçã, goiabeira serrana e citrus produziu um fragmento de aproximadamente 600 pares de bases (pb para todos os isolados analisados

  2. Viruses as new agents of organomineralization in the geological record.

    Science.gov (United States)

    Pacton, Muriel; Wacey, David; Corinaldesi, Cinzia; Tangherlini, Michael; Kilburn, Matt R; Gorin, Georges E; Danovaro, Roberto; Vasconcelos, Crisogono

    2014-07-03

    Viruses are the most abundant biological entities throughout marine and terrestrial ecosystems, but little is known about virus-mineral interactions or the potential for virus preservation in the geological record. Here we use contextual metagenomic data and microscopic analyses to show that viruses occur in high diversity within a modern lacustrine microbial mat, and vastly outnumber prokaryotes and other components of the microbial mat. Experimental data reveal that mineral precipitation takes place directly on free viruses and, as a result of viral infections, on cell debris resulting from cell lysis. Viruses are initially permineralized by amorphous magnesium silicates, which then alter to magnesium carbonate nanospheres of ~80-200 nm in diameter during diagenesis. Our findings open up the possibility to investigate the evolution and geological history of viruses and their role in organomineralization, as well as providing an alternative explanation for enigmatic carbonate nanospheres previously observed in the geological record.

  3. Macromolecular Antiviral Agents against Zika, Ebola, SARS, and Other Pathogenic Viruses

    DEFF Research Database (Denmark)

    Schandock, Franziska; Riber, Camilla Frich; Röcker, Annika

    2017-01-01

    . This work performs selection of synthetic polymers as novel broadly active agents and demonstrates activity of these polymers against Zika, Ebola, Lassa, Lyssa, Rabies, Marburg, Ebola, influenza, herpes simplex, and human immunodeficiency viruses. Results presented herein offer structure...

  4. Efecto biofungicida del gel de Aloe vera sobre Mycosphaerella fijiensis, agente causal de la Sigatoka negra en Musa (AAA

    Directory of Open Access Journals (Sweden)

    Edwin Jaramillo Aguilar

    2017-01-01

    Full Text Available El objetivo de este trabajo fue evaluar a nivel in vitro la actividad antifúngica del gel de Aloe vera sobre el crecimiento micelial de Mycosphaerella fijiensis. Se utilizó la técnica de envenenamiento en el medio de cultivo PDA para determinar la actividad antifúngica del gel. El diseño utilizado fue completamente al azar, con siete tratamientos y tres repeticiones. En los tratamientos se utilizó un fungicida químico comercial (propiconazol, a 250 ppm y 500 ppm; un biofungicida comercial (Trichoderma sp. a 500 ppm y 1000 ppm; ambos productos se usaron como testigo químico y biológico, respectivamente; el gel de Aloe vera a 500 ppm y 1000 ppm; y un testigo absoluto. Se determinó diferencias significativas entre los tratamientos (ANOVA, El test de Tukey demostró que todos los tratamientos registraron diferencia significativa (p ≤ 0,05 con respecto al testigo absoluto. El propiconazol presentó el mayor porcentaje de inhibición del micelio (73,10%; el test de Tukey y el porcentaje de inhibición del micelio presentaron valores similares en el control del crecimiento del hongo a los 30 días de inoculación, en los tratamientos gel de Aloe vera y el T6 de Trichoderma sp. Los resultados sugieren que el Aloe vera podría ser un adecuado biofungicida para el control de Mycosphaerella fijiensis, agente causal de la Sigatoka negra.

  5. Nutritional capability of and substrate suitability for Pseudogymnoascus destructans, the causal agent of bat white-nose syndrome.

    Directory of Open Access Journals (Sweden)

    Daniel B Raudabaugh

    Full Text Available Pseudogymnoascus destructans, the causal agent of bat white-nose syndrome, has caused nearly six million deaths in North American bats since its introduction into the United States in 2006. Current research has shown that caves can harbor P. destructans even after the infected bats are removed and bats no longer visit or inhabit previously infected caves. Our research focuses on elucidating reservoir requirements by investigating the nutritional capabilities of and substrate suitability requirements for six different P. destructans isolates from various localities including Illinois, Indiana, New York (Type specimen, and Pennsylvania. Enzyme assays implicate that both urease and b-glucosidase appear to be constitutive, lipase and esterase activity were more rapid than proteinase activity on 6% gelatin, gelatin degradation was accompanied by medium alkalinization, the reduction of thiosulfate generated hydrogen sulfide gas, chitinase and manganese dependent peroxidase activity were not visually demonstrated within eight weeks, and keratinase activity was not evident at pH 8 within eight weeks. We demonstrate that all P. destructans isolates are capable of growth and sporulation on dead fish, insect, and mushroom tissues. Sole nitrogen source assays demonstrated that all P. destructans isolates exhibit Class 2 nitrogen utilization and that growth-dependent interactions occur among different pH and nitrogen sources. Substrate suitability assays demonstrated that all isolates could grow and sporulate on media ranging from pH 5-11 and tolerated media supplemented with 2000 mg/L of calcium and 700 mg/L of three separated sulfur compounds: thiosulfate L-cysteine, and sulfite. All isolates were intolerant to PEG-induced matric potential with delayed germination and growth at -2.5 MPa with no visible germination at -5 MPa. Interestingly, decreasing the surface tension with Tween 80 permitted germination and growth of P. destructans in -5 MPa PEG medium

  6. Nutritional capability of and substrate suitability for Pseudogymnoascus destructans, the causal agent of bat white-nose syndrome.

    Science.gov (United States)

    Raudabaugh, Daniel B; Miller, Andrew N

    2013-01-01

    Pseudogymnoascus destructans, the causal agent of bat white-nose syndrome, has caused nearly six million deaths in North American bats since its introduction into the United States in 2006. Current research has shown that caves can harbor P. destructans even after the infected bats are removed and bats no longer visit or inhabit previously infected caves. Our research focuses on elucidating reservoir requirements by investigating the nutritional capabilities of and substrate suitability requirements for six different P. destructans isolates from various localities including Illinois, Indiana, New York (Type specimen), and Pennsylvania. Enzyme assays implicate that both urease and b-glucosidase appear to be constitutive, lipase and esterase activity were more rapid than proteinase activity on 6% gelatin, gelatin degradation was accompanied by medium alkalinization, the reduction of thiosulfate generated hydrogen sulfide gas, chitinase and manganese dependent peroxidase activity were not visually demonstrated within eight weeks, and keratinase activity was not evident at pH 8 within eight weeks. We demonstrate that all P. destructans isolates are capable of growth and sporulation on dead fish, insect, and mushroom tissues. Sole nitrogen source assays demonstrated that all P. destructans isolates exhibit Class 2 nitrogen utilization and that growth-dependent interactions occur among different pH and nitrogen sources. Substrate suitability assays demonstrated that all isolates could grow and sporulate on media ranging from pH 5-11 and tolerated media supplemented with 2000 mg/L of calcium and 700 mg/L of three separated sulfur compounds: thiosulfate L-cysteine, and sulfite. All isolates were intolerant to PEG-induced matric potential with delayed germination and growth at -2.5 MPa with no visible germination at -5 MPa. Interestingly, decreasing the surface tension with Tween 80 permitted germination and growth of P. destructans in -5 MPa PEG medium within 14 days

  7. The puzzle of new etiological agents in the Americas: Punta del Toro virus another piece?

    Directory of Open Access Journals (Sweden)

    Salim Mattar V

    2017-01-01

    Full Text Available In a recent study of undifferentiated tropical fevers in an endemic area of Colombia, it was shown that not all acute fevers are caused by the dengue virus (1. The complex clinical-epidemiological panorama of tropical fevers has become a puzzle of difficult resolution due to the appearance of new etiological agents in the Americas such as Chikungunya and Zika. For the differential diagnosis Hantavirus, Arenavirus, Orupuche, tick thrombocytopenic virus, Heartland virus, leptospira and malaria should be considered.

  8. Parasitosis intestinales en Argentina: principales agentes causales encontrados en la población y en el ambiente

    Directory of Open Access Journals (Sweden)

    María M Juárez

    Full Text Available Las parasitosis intestinales se encuentran ampliamente distribuidas en el mundo, con mayor prevalencia en los países en desarrollo. Principalmente afectan a los niños, en los que además provocan disminución del desarrollo físico y mental, situación que puede potenciarse enormemente cuando se suma a un estado nutricional deficiente. La Organización Mundial de la Salud las considera una de las principales causas de morbilidad, estrechamente ligada a la pobreza y relacionada con inadecuada higiene personal, incorrecta manipulación de los alimentos crudos, falta de servicios sanitarios, falta de provisión de agua potable y contaminación fecal del ambiente. Algunas enfermedades parasitarias se vinculan con condiciones de transmisión que existen universalmente, por lo que son cosmopolitas, mientras que otras tienen distribución geográfica variable. En los últimos años, debido a la globalización, el movimiento de personas de zonas endémicas a regiones no endémicas ha permitido la diseminación de ciertas parasitosis. Y aunque también influyen en la frecuencia de algunas de estas enfermedades las costumbres de los pueblos, las condiciones ambientales son un factor determinante para la supervivencia de los parásitos. En nuestro país, debido a la diversidad de suelos y condiciones climáticas que existen, es posible hallar variedad de agentes causales de estas parasitosis. El objetivo de este trabajo fue realizar una revisión bibliográfica de los agentes parasitarios causantes de enfermedades entéricas encontrados en la República Argentina, tanto en materia fecal de personas como en el ambiente, ya que la contaminación parasitaria de este último constituye un indicador directo del riesgo de infección por parásitos intestinales.

  9. Murcha do manjericão (Ocimum basilicum no Brasil: agente causal, círculo de plantas hospedeiras e transmissão via semente Sweet basil (Ocimum basilicum wilt in Brazil: causal agent, host range and seed transmission

    Directory of Open Access Journals (Sweden)

    Ailton Reis

    2007-06-01

    Full Text Available O manjericão (Ocimum basilicum L. é uma hortaliça da família Lamiaceae, utilizada na culinária ou como matéria prima para a indústria de fármacos e óleos essenciais. Amostras de plantas de manjericão apresentando sintomas de murcha, seca de hastes e podridão de colo foram coletadas na área rural de Brazlândia (DF durante a estação chuvosa de 2005. Outras duas amostras foram coletadas em plantas cultivadas em campo aberto e casas de vegetação na região de Ponte Alta (DF. Isolados de um fungo, identificado como Fusarium oxysporum, foram obtidos em todas as amostras. Testes de patogenicidade foram conduzidos com mudas das cultivares O. basilicum 'Dark Opal' e 'Italian Large Leaf', e de acessos das espécies O. americanum L. (manjericão de folha miúda, O. campechianum Mill. (alfavaca, Origanum manjorana L. (manjerona, Origanum vulgare L. (orégano, Mentha arvensis L. (menta, Coleus blumei Benth. (tapete, Leonorus sibiricus L. (rubim e Leonotis nepetaefolia (L. W.T. Aiton (cordão-de-frade. Todos os isolados fúngicos mostraram-se altamente virulentos sobre as duas cultivares de manjericão. Em O. campechianum e O. americanum os isolados causaram apenas suave escurecimento vascular e leve redução de crescimento, sendo avirulentos sobre acessos das espécies O. manjorana, O. vulgare, M. arvensis, C. blumei, L. sibiricus e L. nepetaefolia. Este conjunto de dados indicou que o agente causal da doença é o fungo F. oxysporum f. sp. basilici, constituindo-se no primeiro registro formal deste patógeno no Brasil. Os lotes de sementes utilizados nas áreas de ocorrência da doença foram submetidos a um teste de sanidade visando verificar a presença do patógeno. O fungo F. oxysporum f. sp. basilici foi detectado em quatro dos seis lotes e os isolados obtidos das sementes contaminadas mostraram similar sintomatologia e um idêntico perfil de virulência aos verificados em campo e casa de vegetação, sugerindo que as sementes

  10. Specific PCR detection of Fusarium oxysporum f. sp. raphani: a causal agent of Fusarium wilt on radish plants.

    Science.gov (United States)

    Kim, H; Hwang, S-M; Lee, J H; Oh, M; Han, J W; Choi, G J

    2017-08-01

    Fusarium oxysporum, a causal agent of Fusarium wilt, is one of the most important fungal pathogens worldwide, and detection of F. oxysporum DNA at the forma specialis level is crucial for disease diagnosis and control. In this study, two novel F. oxysporum f. sp. raphani (For)-specific primer sets were designed, FOR1-F/FOR1-R and FOR2-F/FOR2-R, to target FOQG_17868 and FOQG_17869 ORFs, respectively, which were selected based on the genome comparison of other formae speciales of F. oxysporum including conglutinans, cubense, lycopersici, melonis, and pisi. The primer sets FOR1-F/FOR1-R and FOR2-F/FOR2-R that amplified a 610- and 425-bp DNA fragment, respectively, were specific to For isolates which was confirmed using a total of 40 F. oxysporum isolates. From infected plants, the FOR2-F/FOR2-R primer set directly detected the DNA fragment of For isolates even when the radish plants were collected in their early stage of disease development. Although the loci targeted by the For-specific primer sets were not likely involved in the pathogenesis, the primer set FOR2-F/FOR2-R is available for the determination of pathogenicity of radish-infecting F. oxysporum isolates. This study is the first report providing novel primer sets to detect F. oxysporum f. sp. raphani. Because plant pathogenic Fusarium oxysporum has been classified into special forms based on its host specificity, identification of F. oxysporum usually requires a pathogenicity assay as well as knowledge of the morphological characteristics. For rapid and reliable diagnosis, this study provides PCR primer sets that specifically detect Fusarium oxysporum f. sp. raphani (For) which is a devastating pathogen of radish plants. Because one of the primer sets directly detected the DNA fragment of For isolates from infected plants, the specific PCR method demonstrated in this study will provide a foundation for integrated disease management practices in commodity crops. © 2017 The Society for Applied Microbiology.

  11. A Distributed Agent Architecture for a Computer Virus Immune System

    National Research Council Canada - National Science Library

    Harmer, Paul

    2000-01-01

    .... Information protection and information assurance are vital components required for achieving superiority in the Infosphere, but these goals are threatened by the exponential birth rate of new computer viruses...

  12. Obesity and infection: reciprocal causality.

    Science.gov (United States)

    Hainer, V; Zamrazilová, H; Kunešová, M; Bendlová, B; Aldhoon-Hainerová, I

    2015-01-01

    Associations between different infectious agents and obesity have been reported in humans for over thirty years. In many cases, as in nosocomial infections, this relationship reflects the greater susceptibility of obese individuals to infection due to impaired immunity. In such cases, the infection is not related to obesity as a causal factor but represents a complication of obesity. In contrast, several infections have been suggested as potential causal factors in human obesity. However, evidence of a causal linkage to human obesity has only been provided for adenovirus 36 (Adv36). This virus activates lipogenic and proinflammatory pathways in adipose tissue, improves insulin sensitivity, lipid profile and hepatic steatosis. The E4orf1 gene of Adv36 exerts insulin senzitizing effects, but is devoid of its pro-inflammatory modalities. The development of a vaccine to prevent Adv36-induced obesity or the use of E4orf1 as a ligand for novel antidiabetic drugs could open new horizons in the prophylaxis and treatment of obesity and diabetes. More experimental and clinical studies are needed to elucidate the mutual relations between infection and obesity, identify additional infectious agents causing human obesity, as well as define the conditions that predispose obese individuals to specific infections.

  13. Phenotypic Diversity of Causal agent Strains of Potato Common Scab (Streptomyces sp. in Chaharmahal va Bakhtiari Province

    Directory of Open Access Journals (Sweden)

    A. A. Fadaei Tehrani

    2016-06-01

    Full Text Available Introduction: Common scab is one of the most important diseases in the potato fields caused by several species of bacteria of the genus Streptomyces. Symptoms and severity of common scab of potato caused by different factors, is different. The control also will be different. Materials and Methods: About 500 samples of potato tubers with common scab symptoms were collected from different regions in Charmahal VA Bakhtiari province during 2009 and 2010. Isolation of causal agent was performed by standard methods, then the isolates were studied, using biochemical, physiological and nutritional standard test. Thus, the color of the colony and spore mass color YMEA medium after 10 to 14 days were examined. The Gram staining reaction was conducted by Suslow et al. (34. Aerobic and anaerobic growth test (O / F in the presence of glucose was done by Hugh and Leifson (14. The isolates ability to use sugars (L-arabinose, D-fructose, D-glucose, D-mannitol, raffinose, sucrose, cellulose, D-xylose, rhamnose and mesoinositol and amino acids were investigated by Faucher et al method (6. Toxic substances inhibiting bacterial growth were evaluated in culture medium malt and yeast extract containing potassium tellurite (10 and 100 micrograms per ml, thallium acetate (10 and 100 micrograms per ml, crystal violet (0.5 g ml and phenol (0.1% by Lambert and Loria method (23. Using lysosomes, total protein of 14 isolates representing of different phenotypes groups and two reference strains of S. acidiscabies and S. scabies, were extracted by Paradis et al. (29, and their diversity was investigated by acrylamide gel electrophoresis contain dodecyl sulfate (SDS according to Laemmeli (22 The pathogenicity of isolates was evaluated by inoculation of radish and potato tubers Schaad et al. (30 method. Isolates were amplified by spore inoculation in the flask containing 100 grams of vermiculite saturated with nutrient solutions (20 g of sucrose, 2.1 grams of L-asparagine, 0

  14. Causality in Classical Electrodynamics

    Science.gov (United States)

    Savage, Craig

    2012-01-01

    Causality in electrodynamics is a subject of some confusion, especially regarding the application of Faraday's law and the Ampere-Maxwell law. This has led to the suggestion that we should not teach students that electric and magnetic fields can cause each other, but rather focus on charges and currents as the causal agents. In this paper I argue…

  15. Chloroquine, an Endocytosis Blocking Agent, Inhibits Zika Virus Infection in Different Cell Models

    Directory of Open Access Journals (Sweden)

    Rodrigo Delvecchio

    2016-11-01

    Full Text Available Zika virus (ZIKV infection in utero might lead to microcephaly and other congenital defects. Since no specific therapy is available thus far, there is an urgent need for the discovery of agents capable of inhibiting its viral replication and deleterious effects. Chloroquine is widely used as an antimalarial drug, anti-inflammatory agent, and it also shows antiviral activity against several viruses. Here we show that chloroquine exhibits antiviral activity against ZIKV in Vero cells, human brain microvascular endothelial cells, human neural stem cells, and mouse neurospheres. We demonstrate that chloroquine reduces the number of ZIKV-infected cells in vitro, and inhibits virus production and cell death promoted by ZIKV infection without cytotoxic effects. In addition, chloroquine treatment partially reveres morphological changes induced by ZIKV infection in mouse neurospheres.

  16. Chloroquine, an Endocytosis Blocking Agent, Inhibits Zika Virus Infection in Different Cell Models.

    Science.gov (United States)

    Delvecchio, Rodrigo; Higa, Luiza M; Pezzuto, Paula; Valadão, Ana Luiza; Garcez, Patrícia P; Monteiro, Fábio L; Loiola, Erick C; Dias, André A; Silva, Fábio J M; Aliota, Matthew T; Caine, Elizabeth A; Osorio, Jorge E; Bellio, Maria; O'Connor, David H; Rehen, Stevens; de Aguiar, Renato Santana; Savarino, Andrea; Campanati, Loraine; Tanuri, Amilcar

    2016-11-29

    Zika virus (ZIKV) infection in utero might lead to microcephaly and other congenital defects. Since no specific therapy is available thus far, there is an urgent need for the discovery of agents capable of inhibiting its viral replication and deleterious effects. Chloroquine is widely used as an antimalarial drug, anti-inflammatory agent, and it also shows antiviral activity against several viruses. Here we show that chloroquine exhibits antiviral activity against ZIKV in Vero cells, human brain microvascular endothelial cells, human neural stem cells, and mouse neurospheres. We demonstrate that chloroquine reduces the number of ZIKV-infected cells in vitro, and inhibits virus production and cell death promoted by ZIKV infection without cytotoxic effects. In addition, chloroquine treatment partially reveres morphological changes induced by ZIKV infection in mouse neurospheres.

  17. Chloroquine, an Endocytosis Blocking Agent, Inhibits Zika Virus Infection in Different Cell Models

    Science.gov (United States)

    Delvecchio, Rodrigo; Higa, Luiza M.; Pezzuto, Paula; Valadão, Ana Luiza; Garcez, Patrícia P.; Monteiro, Fábio L.; Loiola, Erick C.; Dias, André A.; Silva, Fábio J. M.; Aliota, Matthew T.; Caine, Elizabeth A.; Osorio, Jorge E.; Bellio, Maria; O’Connor, David H.; Rehen, Stevens; de Aguiar, Renato Santana; Savarino, Andrea; Campanati, Loraine; Tanuri, Amilcar

    2016-01-01

    Zika virus (ZIKV) infection in utero might lead to microcephaly and other congenital defects. Since no specific therapy is available thus far, there is an urgent need for the discovery of agents capable of inhibiting its viral replication and deleterious effects. Chloroquine is widely used as an antimalarial drug, anti-inflammatory agent, and it also shows antiviral activity against several viruses. Here we show that chloroquine exhibits antiviral activity against ZIKV in Vero cells, human brain microvascular endothelial cells, human neural stem cells, and mouse neurospheres. We demonstrate that chloroquine reduces the number of ZIKV-infected cells in vitro, and inhibits virus production and cell death promoted by ZIKV infection without cytotoxic effects. In addition, chloroquine treatment partially reveres morphological changes induced by ZIKV infection in mouse neurospheres. PMID:27916837

  18. Leaf crinkle disease in urdbean (Vigna mungo L. Hepper): An overview on causal agent, vector and host.

    Science.gov (United States)

    Gautam, Narinder Kumar; Kumar, Krishna; Prasad, Manoj

    2016-05-01

    Urdbean leaf crinkle disease (ULCD) is an economically significant widespread and devastating disease resulting in extreme crinkling, puckering and rugosity of leaves inflicting heavy yield losses annually in major urdbean-producing countries of the world. This disease is caused by urdbean leaf crinkle virus (ULCV). Urdbean (Vigna mungo L. Hepper) is relatively more susceptible than other pulses to leaf crinkle disease. Urdbean is an important and useful crop cultivated in various parts of South-East Asia and well adapted for cultivation under semi-arid and subtropical conditions. Aphids, insects and whiteflies have been reported as vectors of the disease. The virus is also transmitted through sap inoculation, grafting and seed. The loss in seed yield in ULCD-affected urdbean crop ranges from 35 to 81%, which is dependent upon type of genotype location and infection time. The diseased material and favourable climatic conditions contribute for the widespread viral disease. Anatomical and biochemical changes take place in the affected diseased plants. Genetic variations have been reported in the germplasm screening which suggest continuous screening of available varieties and new germplasm to search for new traits (new genes) and identify new sources of disease resistance. There are very few reports on breeding programmes for the development and release of varieties tolerant to ULCD. Mostly random amplified polymorphic DNA (RAPD) as well as inter-simple sequence repeat (ISSR) molecular markers have been utilized for fingerprinting of blackgram, and a few reports are there on sequence-tagged micro-satellite site (STMS) markers. There are so many RNA viruses which have also developed strategies to counteract silencing process by encoding suppressor proteins that create hindrances in the process. But, in the case of ULCV, there is no report available indicating which defence pathway is operating for its resistance in the plants and whether same silencing suppression

  19. Effect of Antiviral Agents in Equine Abortion Virus-Infected Hamsters1

    Science.gov (United States)

    Lieberman, Melvin; Pascale, Andrea; Schafer, Thomas W.; Came, Paul E.

    1972-01-01

    Equine abortion virus, a member of the herpesvirus group, produces a lethal infection in hamsters. With this system, the protective effect of certain inhibitors of deoxyribonucleic acid viruses, inducers of interferon and exogenous interferon, was evaluated. Of the various agents studied, 9-β-d-arabinofuranosyladenine markedly suppressed mortality, and 5-iodo-2′-deoxyuridine, distamycin A, and N-ethylisatin β-thiosemicarbazone were inactive. Of the inducers tested, statolon, ultraviolet-irradiated Newcastle disease virus, and polyriboinosinic:polyribocytidylic acid (poly I:C) were protective, and endotoxin, polyacrylic acid, and polymethacrylic acid did not protect. Administration of exogenous interferon did not afford protection. Statolon and ultraviolet-irradiated Newcastle disease virus induced circulating interferon in hamsters, whereas poly I:C, endotoxin, and polyacrylic acid did not produce interferon. Because of the severity of the disease produced in hamsters by equine abortion virus, lack of protective activity by an agent in this system should not preclude possible efficacy against other members of the herpesvirus group. PMID:4376907

  20. Construction and characterization of a bacterial artificial chromosome library of the causal agent of Black Sigatoka fungal leaf spot disease of banana and plantain, Mycosphaerella fijiensis.

    Science.gov (United States)

    Canto-Canché, Blondy; Guillén-Maldonado, Diana Karina; Peraza-Echeverría, Leticia; Conde-Ferráez, Laura; James-Kay, Andrew

    2007-05-01

    A bacterial artificial chromosome library of the causal agent of the Black Sigatoka leaf spot disease of banana and plantain, Mycosphaerella fijiensis, has been constructed using a non-sphaeroplasting technique and characterized using both homologous and heterologous probes. After first and a second size selection of PFGE-fractionated DNA, a ligation was obtained using a 1:4 molar ratio (insert:vector). One hundred random clones were analyzed, and the mean insert size was estimated to be 90 kb. The range of the insert sizes was between 40 and 160 kb. The highest percentage of inserts belonged to the range between 80 and 100 kb; 32% of the inserts had 2 or 3 internal NotI sites. This library consists of 1920 clones, if the genomic size is at least 35 Mb, then this represents 4.9 x genome equivalents, which was supported by hybridization results with homologous and heterologous probes.

  1. Effect of bodily fluids from honey bee (Apis mellifera) larvae on growth and genome-wide transcriptional response of the causal agent of American Foulbrood disease (Paenibacillus larvae).

    Science.gov (United States)

    De Smet, Lina; De Koker, Dieter; Hawley, Alyse K; Foster, Leonard J; De Vos, Paul; de Graaf, Dirk C

    2014-01-01

    Paenibacillus larvae, the causal agent of American Foulbrood disease (AFB), affects honey bee health worldwide. The present study investigates the effect of bodily fluids from honey bee larvae on growth velocity and transcription for this Gram-positive, endospore-forming bacterium. It was observed that larval fluids accelerate the growth and lead to higher bacterial densities during stationary phase. The genome-wide transcriptional response of in vitro cultures of P. larvae to larval fluids was studied by microarray technology. Early responses of P. larvae to larval fluids are characterized by a general down-regulation of oligopeptide and sugar transporter genes, as well as by amino acid and carbohydrate metabolic genes, among others. Late responses are dominated by general down-regulation of sporulation genes and up-regulation of phage-related genes. A theoretical mechanism of carbon catabolite repression is discussed.

  2. Rickettsia typhi in rodents and R. felis in fleas in Yucatán as a possible causal agent of undefined febrile cases.

    Science.gov (United States)

    Peniche-Lara, Gaspar; Dzul-Rosado, Karla; Pérez-Osorio, Carlos; Zavala-Castro, Jorge

    2015-01-01

    Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chain reaction technique and sequencing. The study only identified the presence of Rickettsia typhi in blood samples obtained from Rattus rattus and it reported, for the first time, the presence of R. felis in the flea Polygenis odiosus collected from Ototylomys phyllotis rodent. Additionally, Rickettsia felis was detected in the ectoparasite Ctenocephalides felis fleas parasitizing the wild rodent Peromyscus yucatanicus. This study's results contributed to a better knowledge of Rickettsia epidemiology in Yucatán.

  3. First isolation of Mycoplasma capricolum subsp. capricolum, one of the causal agents of caprine contagious agalactia, on the island of Lanzarote (Spain).

    Science.gov (United States)

    De la Fe, C; Gutiérrez, A; Poveda, J B; Assunção, P; Ramírez, A S; Fabelo, F

    2007-03-01

    During an unusually long period of bad weather, several outbreaks of caprine contagious agalactia (CCA) were reported in a number of flocks on the island of Lanzarote (Canary Islands, Spain). Clinical and subclinical mastitis in lactating goats and some cases of arthritis and pneumonia in kids were observed in the affected flocks. Mycoplasma capricolum subsp. capricolum was isolated as the main causal agent of the outbreaks, associated with M. mycoides subsp. mycoides "large colony type" (Mmm LC) in two flocks. This is the first report of an isolation of M. capricolum subsp. capricolum on the island of Lanzarote. The finding is of epidemiological importance and could complicate plans to control the disease. The significance of this mycoplasma species in association with CCA must now be studied in detail.

  4. Causality in Europeanization Research

    DEFF Research Database (Denmark)

    Lynggaard, Kennet

    2012-01-01

    to develop discursive institutional analytical frameworks and something that comes close to the formulation of hypothesis on the effects of European Union (EU) policies and institutions on domestic change. Even if these efforts so far do not necessarily amount to substantive theories or claims of causality......Discourse analysis as a methodology is perhaps not readily associated with substantive causality claims. At the same time the study of discourses is very much the study of conceptions of causal relations among a set, or sets, of agents. Within Europeanization research we have seen endeavours......, it suggests that discourse analysis and the study of causality are by no means opposites. The study of Europeanization discourses may even be seen as an essential step in the move towards claims of causality in Europeanization research. This chapter deals with the question of how we may move from the study...

  5. General properties of grapevine viruses occurring in Hungary

    Directory of Open Access Journals (Sweden)

    Eszter Cseh

    2012-03-01

    Full Text Available The past fifty years important advances have been made in the field of grapevine virus research, including characterization of pathogens and control measurements. Still the occurrence of Grapevine fanleaf virus (GFLV, Arabis mosaic virus (ArMV, Tomato black ring virus (TBRV, Grapevine chrome mosaic virus (GCMV, Alfalfa mosaic virus (AMV, Grapevine Bulgarian latent virus (GBLV, Grapevine fleck virus (GFkV, Grapevine leafroll- associated viruses (GLRaV1-4, Grapevine virus A (GVA, Grapevine virus B (GVB and Grapevine rupestris stem pitting- associated virus (GRSPaV have been reported in Hungary and characterized by conventional methods as woody indexing, herbaceous indexing and serological methods. Among grapevine viruses the Grapevine line pattern virus (GLPV seems to be uncial; because it was reported only in Hungary. Causal agents of several grapevine diseases, like enation, vein necrosis and vein mosaic remained undiscovered. These virus-like diseases occurred only sporadically, without economic importance.

  6. Effect of Two Biological Formulations Based on Bacillus subtilis and Pseudomonas fluorescens on Control of Didymella applanata, the Causal Agent of Red Raspberry Cane Spur Blight

    Directory of Open Access Journals (Sweden)

    Margarita Shternshis

    2016-01-01

    Full Text Available In vitro and in vivo studies were conducted to estimate the efficacy of the two microbial formulations based on Bacillus subtilis Cohn. and Pseudomonas fluorescens Mig. on the fungus Didymella applanata (Niessl. Sacc., the causal agent of red raspberry (Rubus idaeus L. spur blight. In vitro, both bacteria reduced the growth of D. applanata. In inoculation experiments with raspberry canes in two cultivars with different susceptibility to D. applanata, these antagonistic bacteria suppressed fungal development by reducing the lesions area and the number of D. applanata fruiting bodies. Field trials of two biological formulations under natural conditions showed a significant suppression of the disease. B. subtilis and P. fluorescens included in the formulations revealed antagonistic activity towards D. applanata that depended on the red raspberry cultivar and weather conditions. In all cases, B. subtilis showed better results than P. fluorescens in biocontrol of the raspberry spur blight. This study demonstrated for the first time the ability of the biocontrol agents B. subtilis and P. fluorescens to suppress red raspberry cane spur blight, a serious worldwide disease.

  7. Cladosporium cladosporioides and Cladosporium pseudocladosporioides as potential new fungal antagonists of Puccinia horiana Henn., the causal agent of chrysanthemum white rust.

    Directory of Open Access Journals (Sweden)

    David Eduardo Torres

    Full Text Available Puccinia horiana Hennings, the causal agent of chrysanthemum white rust, is a worldwide quarantine organism and one of the most important fungal pathogens of Chrysanthemum × morifolium cultivars, which are used for cut flowers and as potted plants in commercial production regions of the world. It was previously reported to be controlled by Lecanicillium lecanii, Cladosporium sphaerospermum, C. uredinicola and Aphanocladium album, due to their antagonistic and hyperparasitic effects. We report novel antagonist species on Puccinia horiana. Fungi isolated from rust pustules in a commercial greenhouse from Villa Guerrero, México, were identified as Cladosporium cladosporioides and Cladosporium pseudocladosporioides based upon molecular analysis and morphological characters. The antagonism of C. cladosporioides and C. pseudocladosporioides on chrysanthemum white rust was studied using light and electron microscopy in vitro at the host/parasite interface. Cladosporium cladosporioides and C. pseudocladosporioides grew towards the white rust teliospores and colonized the sporogenous cells, but no direct penetration of teliospores was observed; however, the structure and cytoplasm of teliospores were altered. The two Cladosporium spp. were able to grow on media containing laminarin, but not when chitin was used as the sole carbon source; these results suggest that they are able to produce glucanases. Results from the study indicate that both Cladosporium species had potential as biological control agents of chrysanthemum white rust.

  8. Controle alternativo de Colletotrichum acutatum agente causal da queda prematura dos frutos cítricos Alternative control of Colletotrichum acutatum, causal agent of postbloom fruit drop of citrus

    Directory of Open Access Journals (Sweden)

    Katia Cristina Kupper

    2009-12-01

    Full Text Available A queda prematura dos frutos cítricos (QPFC, causada por Colletotrichum acutatum, dados os grandes prejuízos que têm causado aos produtores, constitui-se numa doença de grande importância econômica. O controle da doença é feito predominantemente mediante uso de fungicidas, que eleva o custo de produção e afeta negativamente o meio ambiente. Diante disso, este trabalho teve por objetivo buscar um método alternativo de controle da QPFC, mediante o uso de agentes de biocontrole ou de biofertilizantes. Diferentes concentrações de biofertilizantes (originários de duas fontes distintas e denominados de Bio1 e Bio 2; três isolados de Bacillus subtilis (ACB-69; 72 e 77 e três isolados de Trichoderma spp. (ACB-14; 37 e 39 foram testados, isoladamente ou em combinação, sob condições de laboratório, quanto à capacidade inibitória da germinação de conídios de C. acutatum. Estudaram-se, ainda, a produção de metabólitos termoestáveis por B. subtilis e o efeito sobre a germinação do patógeno. Quinze isolados de B. subtilis foram testados quanto à capacidade de prevenir a infecção por C. acutatum em flores destacadas de lima- ácida 'Tahiti' e, no campo, foram instalados dois experimentos, visando a testar ACBs e biofertilizantes no controle da doença. Verificou-se que o isolado ACB-72 (B. subtilis e ACB-37 (T. pseudokoningii foram os que mais inibiram a germinação do patógeno. Quanto à produção de metabólitos termoestáveis, ACB-69 e 77 foram os mais eficientes em produzir substâncias antifúngicas, e em quantidades suficientes para inibirem a germinação do patógeno. A mistura dos quatro isolados de Bacillus (ACBs: 69; 72; 77 e AP3 foi o que apresentou maior porcentagem de inibição (73%. Os biofertilizantes (Bio1 e Bio2, em concentrações acima de 10% e, quando em associação com isolados de Trichoderma spp., promoveram maiores inibições na germinação de C. acutatum. Em testes com flores destacadas

  9. Functional and biophysical studies on four ceratoplatanins from the fungus Moniliophthora perniciosa, causal agent of the Witche's broom disease

    International Nuclear Information System (INIS)

    Barsottini, M.; Zaparoli, G.; Garcia, O.; Pereira, G.A.G.; Oliveira, J.F.; Tiezzi, H.O.; Ambrosio, A.L.B.; Dias, S.M.G.

    2012-01-01

    Full text: Ceratoplatanin (CP) is a secreted protein of 12.4 kDa initially identified in culture filtrates of the disease ascomycete Ceratocystis fimbriata f. sp. platani, etiological agent of the canker stain disease. CP is also the founding member of the namesake protein family, which contains fungal-secreted proteins involved in various stages of the host-fungus interaction and may act as phytotoxins or elicitors of defense response. Besides the low molecular weight, CPs have a high percentage of hydrophobic residues and share two conserved intramolecular disulfide bonds. It has been suggested that CPs have important physiological functions, including interaction with cell wall or cell membrane and manipulation of the host's defense system. Furthermore, a recent work showed that the ceratoplatanin from C. fimbriata has some degree of affinity for the saccharide 4-N-acetylglucosamine. However, its precise molecular function remains elusive. Five putative CPs have been identified in Moniliophthora perniciosa a basidiomycete fungus responsible for great economic losses in cocoa industry in the form of Witches' broom disease (WBD) , four of which had their crystal structures resolved by our group. In this work we report biophysical and functional studies on these MpCPs aiming at understanding their role and importance during the WBD progression. (author)

  10. A review of the Mycrocylus ulei Ascomycetes fungus, causative agent of South American rubber-leaf blight Revisión sobre el hongo Microcyclus ulei, agente causal del mal suramericano de la hoja del caucho

    Directory of Open Access Journals (Sweden)

    Ancízar Aristizábar Fabio

    2006-12-01

    Full Text Available The Microcyclus ulei Ascomycetes fungus is the causal agent of south-American leaf blight (SALB, this being one of the most important diseases affecting the natural rubber tree (Hevea brasiliensis in Latina-America and has been responsible for numerous economic losses. This fungus has presented high physiological variability, suggesting its great adaptability. HCN tolerance has been described as being one of the mechanisms associated with its virulence. Resistant Hevea clones have been obtained by genetic improvement; however, the mechanisms associated with this are still not well known. Greater knowledge of this pathogen will lead to developing new control strategies and better understanding of the mechanisms associated with host resistance. Key words: Microcyclus ulei, SALB, Hevea brasiliensis.El hongo ascomycete Microcyclus ulei es el agente causal del SALB que es una de las enfermedades más importan­tes del árbol de caucho natural (Hevea brasiliensis en América Latina y ha sido responsable de numerosas pérdidas económicas. Este hongo ha presentado alta variabilidad fisiológica y se sugiere su alta adaptabilidad, dentro de los mecanismos asociados a su virulencia se ha descrito la tolerancia al HCN. Se han obtenido clones de Hevea resistentes mediante mejoramiento genético, sin embargo, aun no son bien conocidos los mecanismos asociados a ésta. Un mayor conocimiento de este patógeno permitirá el desarrollo de nuevas estrategias de control así como el mayor entendimiento de los mecanismos asociados a resistencia del hospedero. Palabras clave: Microcyclus ulei, SALB, Hevea brasiliensis.

  11. Causal universe

    CERN Document Server

    Ellis, George FR; Pabjan, Tadeusz

    2013-01-01

    Written by philosophers, cosmologists, and physicists, this collection of essays deals with causality, which is a core issue for both science and philosophy. Readers will learn about different types of causality in complex systems and about new perspectives on this issue based on physical and cosmological considerations. In addition, the book includes essays pertaining to the problem of causality in ancient Greek philosophy, and to the problem of God's relation to the causal structures of nature viewed in the light of contemporary physics and cosmology.

  12. The genomic sequence of ectromelia virus, the causative agent of mousepox

    International Nuclear Information System (INIS)

    Chen Nanhai; Danila, Maria I.; Feng Zehua; Buller, R. Mark L.; Wang Chunlin; Han Xiaosi; Lefkowitz, Elliot J.; Upton, Chris

    2003-01-01

    Ectromelia virus is the causative agent of mousepox, an acute exanthematous disease of mouse colonies in Europe, Japan, China, and the U.S. The Moscow, Hampstead, and NIH79 strains are the most thoroughly studied with the Moscow strain being the most infectious and virulent for the mouse. In the late 1940s mousepox was proposed as a model for the study of the pathogenesis of smallpox and generalized vaccinia in humans. Studies in the last five decades from a succession of investigators have resulted in a detailed description of the virologic and pathologic disease course in genetically susceptible and resistant inbred and out-bred mice. We report the DNA sequence of the left-hand end, the predicted right-hand terminal repeat, and central regions of the genome of the Moscow strain of ectromelia virus (approximately 177,500 bp), which together with the previously sequenced right-hand end, yields a genome of 209,771 bp. We identified 175 potential genes specifying proteins of between 53 and 1924 amino acids, and 29 regions containing sequences related to genes predicted in other poxviruses, but unlikely to encode for functional proteins in ectromelia virus. The translated protein sequences were compared with the protein database for structure/function relationships, and these analyses were used to investigate poxvirus evolution and to attempt to explain at the cellular and molecular level the well-characterized features of the ectromelia virus natural life cycle

  13. Effect of Raspberry bushy dwarf virus, Raspberry leaf mottle virus, and Raspberry latent virus on plant growth and fruit crumbliness in ‘Meeker’ red Raspberry

    Science.gov (United States)

    Raspberry crumbly fruit in red raspberry (Rubus idaeus L.), widespread in the Pacific Northwest of the United States and British Columbia, Canada, is most commonly caused by a virus infection. Raspberry bushy dwarf virus (RBDV) has long been attributed as the causal agent of the disease. Recently, t...

  14. Causal and causally separable processes

    Science.gov (United States)

    Oreshkov, Ognyan; Giarmatzi, Christina

    2016-09-01

    The idea that events are equipped with a partial causal order is central to our understanding of physics in the tested regimes: given two pointlike events A and B, either A is in the causal past of B, B is in the causal past of A, or A and B are space-like separated. Operationally, the meaning of these order relations corresponds to constraints on the possible correlations between experiments performed in the vicinities of the respective events: if A is in the causal past of B, an experimenter at A could signal to an experimenter at B but not the other way around, while if A and B are space-like separated, no signaling is possible in either direction. In the context of a concrete physical theory, the correlations compatible with a given causal configuration may obey further constraints. For instance, space-like correlations in quantum mechanics arise from local measurements on joint quantum states, while time-like correlations are established via quantum channels. Similarly to other variables, however, the causal order of a set of events could be random, and little is understood about the constraints that causality implies in this case. A main difficulty concerns the fact that the order of events can now generally depend on the operations performed at the locations of these events, since, for instance, an operation at A could influence the order in which B and C occur in A’s future. So far, no formal theory of causality compatible with such dynamical causal order has been developed. Apart from being of fundamental interest in the context of inferring causal relations, such a theory is imperative for understanding recent suggestions that the causal order of events in quantum mechanics can be indefinite. Here, we develop such a theory in the general multipartite case. Starting from a background-independent definition of causality, we derive an iteratively formulated canonical decomposition of multipartite causal correlations. For a fixed number of settings and

  15. Causal and causally separable processes

    International Nuclear Information System (INIS)

    Oreshkov, Ognyan; Giarmatzi, Christina

    2016-01-01

    The idea that events are equipped with a partial causal order is central to our understanding of physics in the tested regimes: given two pointlike events A and B , either A is in the causal past of B , B is in the causal past of A , or A and B are space-like separated. Operationally, the meaning of these order relations corresponds to constraints on the possible correlations between experiments performed in the vicinities of the respective events: if A is in the causal past of B , an experimenter at A could signal to an experimenter at B but not the other way around, while if A and B are space-like separated, no signaling is possible in either direction. In the context of a concrete physical theory, the correlations compatible with a given causal configuration may obey further constraints. For instance, space-like correlations in quantum mechanics arise from local measurements on joint quantum states, while time-like correlations are established via quantum channels. Similarly to other variables, however, the causal order of a set of events could be random, and little is understood about the constraints that causality implies in this case. A main difficulty concerns the fact that the order of events can now generally depend on the operations performed at the locations of these events, since, for instance, an operation at A could influence the order in which B and C occur in A ’s future. So far, no formal theory of causality compatible with such dynamical causal order has been developed. Apart from being of fundamental interest in the context of inferring causal relations, such a theory is imperative for understanding recent suggestions that the causal order of events in quantum mechanics can be indefinite. Here, we develop such a theory in the general multipartite case. Starting from a background-independent definition of causality, we derive an iteratively formulated canonical decomposition of multipartite causal correlations. For a fixed number of settings and

  16. In vitro Antagonistic Mechanisms of Trichoderma spp. and Talaromyces flavus to Control Gaeumannomyces graminis var. tritici the Causal Agent of Wheat Take-all Disease

    Directory of Open Access Journals (Sweden)

    Seddighe Mohammadi

    2015-07-01

    Full Text Available Wheat take-all disease caused by Gaeumannomyces graminis var. tritici has recently been detected in different regions of Iran. With respect to biocontrol effect of Trichoderma spp. on many pathogenic fungi, seven isolates of Trichoderma and four isolates of Talaromyces were in vitro evaluated in terms of their biological control against the disease causal agent. In dual culture test the five isolates showed efficient competition for colonization against pathogenic fungus and the highest percentages of inhibition belonging to Talaromyces flavus 60 and Talaromyces flavus 136 were 59.52 and 57.61%, respectively. Microscopic investigations showed that in regions where antagonistic isolates and Gaeumannomyces graminis var. tritici coincide, hyphal contact, penetration and fragmentation of Gaeumannomyces graminis var. tritici were observed. Investigating the effect of volatile and non-volatile compounds at 10 ml concentration showed that the highest inhibition percentage on mycelium growth of the pathogen caused by T. harzianum (44.76% and T. longibrachiatum (52.38% respectively.

  17. In vitro antibacterial effect of exotic plants essential oils on the honeybee pathogen Paenibacillus larvae, causal agent of American foul brood

    Energy Technology Data Exchange (ETDEWEB)

    Fuselli, S. R.; Garcia de la Rosa, S. B.; Eguaras, M. J.; Fritz, R.

    2010-07-01

    Chemical composition and antimicrobial activity of exotic plants essential oils to potentially control Paenibacillus larvae, the causal agent of American foul brood disease (AFB) were determined. AFB represents one of the main plagues that affect the colonies of honeybees Apis mellifera L. with high negative impact on beekeepers worldwide. Essential oils tested were niaouli (Melaleuca viridiflora) and tea tree (Melaleuca alternifolia) from Myrtaceae, and citronella grass (Cymbopogon nardus) and palmarosa (Cymbopogon martinii) from Gramineae. The components of the essential oils were identified by SPME-GC/MS analysis. The antimicrobial activity of the oils against P. larvae was determined by the broth micro dilution method. In vitro assays of M. viridiflora and C. nardus oils showed the inhibition of the bacterial strains at the lowest concentrations tested, with minimal inhibitory concentration (MIC) mean value about 320 mg L{sup -}1 for both oils, respectively. This property could be attributed to the kind and percentage of the components of the oils. Terpinen-4-ol (29.09%), {alpha}-pinene (21.63%) and limonene (17.4%) were predominant in M. viridiflora, while limonene (24.74%), citronelal (24.61%) and geraniol (15.79%) were the bulk of C. nardus. The use of these essential oils contributes to the screening of alternative natural compounds to control AFB in the apiaries; toxicological risks and other undesirable effects would be avoided as resistance factors, developed by the indiscriminate use of antibiotics. (Author) 40 refs.

  18. Variable number of tandem repeat markers in the genome sequence of Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana (Musa spp).

    Science.gov (United States)

    Garcia, S A L; Van der Lee, T A J; Ferreira, C F; Te Lintel Hekkert, B; Zapater, M-F; Goodwin, S B; Guzmán, M; Kema, G H J; Souza, M T

    2010-11-09

    We searched the genome of Mycosphaerella fijiensis for molecular markers that would allow population genetics analysis of this plant pathogen. M. fijiensis, the causal agent of banana leaf streak disease, also known as black Sigatoka, is the most devastating pathogen attacking bananas (Musa spp). Recently, the entire genome sequence of M. fijiensis became available. We screened this database for VNTR markers. Forty-two primer pairs were selected for validation, based on repeat type and length and the number of repeat units. Five VNTR markers showing multiple alleles were validated with a reference set of isolates from different parts of the world and a population from a banana plantation in Costa Rica. Polymorphism information content values varied from 0.6414 to 0.7544 for the reference set and from 0.0400 and 0.7373 for the population set. Eighty percent of the polymorphism information content values were above 0.60, indicating that the markers are highly informative. These markers allowed robust scoring of agarose gels and proved to be useful for variability and population genetics studies. In conclusion, the strategy we developed to identify and validate VNTR markers is an efficient means to incorporate markers that can be used for fungicide resistance management and to develop breeding strategies to control banana black leaf streak disease. This is the first report of VNTR-minisatellites from the M. fijiensis genome sequence.

  19. Rickettsia typhi IN RODENTS AND R. felis IN FLEAS IN YUCATÁN AS A POSSIBLE CAUSAL AGENT OF UNDEFINED FEBRILE CASES

    Directory of Open Access Journals (Sweden)

    Gaspar PENICHE-LARA

    2015-04-01

    Full Text Available Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chain reaction technique and sequencing. The study only identified the presence of Rickettsia typhi in blood samples obtained from Rattus rattus and it reported, for the first time, the presence of R. felis in the flea Polygenis odiosus collected from Ototylomys phyllotis rodent. Additionally, Rickettsia felis was detected in the ectoparasite Ctenocephalides felis fleas parasitizing the wild rodent Peromyscus yucatanicus. This study’s results contributed to a better knowledge of Rickettsia epidemiology in Yucatán.

  20. Recent characterization of cowpea aphid-borne mosaic virus ...

    African Journals Online (AJOL)

    Woodiness disease is the most important disorder of passion fruit worldwide. The causal agent in Brazil is the Cowpea aphid-borne mosaic virus (CABMV), and despite the economic relevance of passion fruit for agriculture there have been recently very few studies about this virus in Brazil and worldwide. This work reveals ...

  1. First discovery of acetone extract from cottonseed oil sludge as a novel antiviral agent against plant viruses.

    Science.gov (United States)

    Zhao, Lei; Feng, Chaohong; Hou, Caiting; Hu, Lingyun; Wang, Qiaochun; Wu, Yunfeng

    2015-01-01

    A novel acetone extract from cottonseed oil sludge was firstly discovered against plant viruses including Tobacco mosaic virus (TMV), Rice stripe virus (RSV) and Southern rice black streaked dwarf virus (SRBSDV). Gossypol and β-sitosterol separated from the acetone extract were tested for their effects on anti-TMV and analysed by nuclear magnetic resonance (NMR) assay. In vivo and field trials in different geographic distributions and different host varieties declared that this extract mixture was more efficient than the commercial agent Ningnanmycin with a broad spectrum of anti-plant-viruses activity. No phytotoxic activity was observed in the treated plants and environmental toxicology showed that this new acetone extract was environmentally friendly, indicating that this acetone extract has potential application in the control of plant virus in the future.

  2. Use of Aptamers as Diagnostics Tools and Antiviral Agents for Human Viruses

    Directory of Open Access Journals (Sweden)

    Víctor M. González

    2016-12-01

    Full Text Available Appropriate diagnosis is the key factor for treatment of viral diseases. Time is the most important factor in rapidly developing and epidemiologically dangerous diseases, such as influenza, Ebola and SARS. Chronic viral diseases such as HIV-1 or HCV are asymptomatic or oligosymptomatic and the therapeutic success mainly depends on early detection of the infective agent. Over the last years, aptamer technology has been used in a wide range of diagnostic and therapeutic applications and, concretely, several strategies are currently being explored using aptamers against virus proteins. From a diagnostics point of view, aptamers are being designed as a bio-recognition element in diagnostic systems to detect viral proteins either in the blood (serum or plasma or into infected cells. Another potential use of aptamers is for therapeutics of viral infections, interfering in the interaction between the virus and the host using aptamers targeting host-cell matrix receptors, or attacking the virus intracellularly, targeting proteins implicated in the viral replication cycle. In this paper, we review how aptamers working against viral proteins are discovered, with a focus on recent advances that improve the aptamers’ properties as a real tool for viral infection detection and treatment.

  3. Phytophthora palmivora, agente da podridão de raiz e frutos de mamoeiro no Estado de Alagoas Phytophthora palmivora, causal agent of root and fruit rots of papaya in the State of Alagoas, Brazil

    Directory of Open Access Journals (Sweden)

    Juliana Paiva Carnaúba

    2006-04-01

    Full Text Available O mamoeiro (Carica papaya é uma das mais importantes fruteiras tropicais, e seus frutos contribuem com uma produção de 1,65 milhão de toneladas por ano para o Brasil. Um isolado de Phytophthora sp. obtido de frutos de mamoeiro da cultivar Havaí, em Alagoas, foi caracterizado morfologicamente e sua patogenicidade foi confirmada em frutos e mudas deste hospedeiro. Em meio suco V-8, os esporangióforos apresentaram-se delgados, simples ou pouco ramificados, enquanto os esporângios se apresentaram ovóides a elipsóides, proeminentemente papilados e um pedicelo curto na porção basal, medindo em média 37,68 x 27,52 mm. Através das características apresentadas pelo isolado e os sintomas induzidos, o agente causal foi identificado como Phytophthora palmivora. Apesar de essa doença já ocorrer em outros estados, como Bahia, Espírito Santo, São Paulo, Pernambuco e Pará, este é o primeiro relato de Phytophthora palmivora em mamoeiro no Estado de Alagoas.The papaya (Carica papaya is one of the most important tropical fruit crops and its fruit contribute with a production of 1.65 millions tons/year in Brazil. An isolated of Phytophthora sp. gotten from papaya fruits cv. Hawaii, in the state of Alagoas, was characterized morphologically and its pathogenicity to this fruits and seedling was confirmed. In a V-8 medium, the sporangiophores presented to be slim, simple or little ramified, while the sporangia presented ovoid to ellipsoid, prominently papillae and one short pedicel in the basal portion, measuring in average 37,68 x 27,52 (m. Through the characteristics presented by the isolated and the induced symptoms, the causal agent was identified as Phytophthora palmivora. Despite of this disease already occurring in other states like in Bahia, Espirito Santo, São Paulo, Pernambuco and Pará, this is the first report of Phytophthora palmivora on papaya in the state of Alagoas, Brazil.

  4. A Multiplex PCR/LDR Assay for the Simultaneous Identification of Category A Infectious Pathogens: Agents of Viral Hemorrhagic Fever and Variola Virus.

    Directory of Open Access Journals (Sweden)

    Sanchita Das

    Full Text Available CDC designated category A infectious agents pose a major risk to national security and require special action for public health preparedness. They include viruses that cause viral hemorrhagic fever (VHF syndrome as well as variola virus, the agent of smallpox. VHF is characterized by hemorrhage and fever with multi-organ failure leading to high morbidity and mortality. Smallpox, a prior scourge, has been eradicated for decades, making it a particularly serious threat if released nefariously in the essentially non-immune world population. Early detection of the causative agents, and the ability to distinguish them from other pathogens, is essential to contain outbreaks, implement proper control measures, and prevent morbidity and mortality. We have developed a multiplex detection assay that uses several species-specific PCR primers to generate amplicons from multiple pathogens; these are then targeted in a ligase detection reaction (LDR. The resultant fluorescently-labeled ligation products are detected on a universal array enabling simultaneous identification of the pathogens. The assay was evaluated on 32 different isolates associated with VHF (ebolavirus, marburgvirus, Crimean Congo hemorrhagic fever virus, Lassa fever virus, Rift Valley fever virus, Dengue virus, and Yellow fever virus as well as variola virus and vaccinia virus (the agent of smallpox and its vaccine strain, respectively. The assay was able to detect all viruses tested, including 8 sequences representative of different variola virus strains from the CDC repository. It does not cross react with other emerging zoonoses such as monkeypox virus or cowpox virus, or six flaviviruses tested (St. Louis encephalitis virus, Murray Valley encephalitis virus, Powassan virus, Tick-borne encephalitis virus, West Nile virus and Japanese encephalitis virus.

  5. A Multiplex PCR/LDR Assay for the Simultaneous Identification of Category A Infectious Pathogens: Agents of Viral Hemorrhagic Fever and Variola Virus.

    Science.gov (United States)

    Das, Sanchita; Rundell, Mark S; Mirza, Aashiq H; Pingle, Maneesh R; Shigyo, Kristi; Garrison, Aura R; Paragas, Jason; Smith, Scott K; Olson, Victoria A; Larone, Davise H; Spitzer, Eric D; Barany, Francis; Golightly, Linnie M

    2015-01-01

    CDC designated category A infectious agents pose a major risk to national security and require special action for public health preparedness. They include viruses that cause viral hemorrhagic fever (VHF) syndrome as well as variola virus, the agent of smallpox. VHF is characterized by hemorrhage and fever with multi-organ failure leading to high morbidity and mortality. Smallpox, a prior scourge, has been eradicated for decades, making it a particularly serious threat if released nefariously in the essentially non-immune world population. Early detection of the causative agents, and the ability to distinguish them from other pathogens, is essential to contain outbreaks, implement proper control measures, and prevent morbidity and mortality. We have developed a multiplex detection assay that uses several species-specific PCR primers to generate amplicons from multiple pathogens; these are then targeted in a ligase detection reaction (LDR). The resultant fluorescently-labeled ligation products are detected on a universal array enabling simultaneous identification of the pathogens. The assay was evaluated on 32 different isolates associated with VHF (ebolavirus, marburgvirus, Crimean Congo hemorrhagic fever virus, Lassa fever virus, Rift Valley fever virus, Dengue virus, and Yellow fever virus) as well as variola virus and vaccinia virus (the agent of smallpox and its vaccine strain, respectively). The assay was able to detect all viruses tested, including 8 sequences representative of different variola virus strains from the CDC repository. It does not cross react with other emerging zoonoses such as monkeypox virus or cowpox virus, or six flaviviruses tested (St. Louis encephalitis virus, Murray Valley encephalitis virus, Powassan virus, Tick-borne encephalitis virus, West Nile virus and Japanese encephalitis virus).

  6. Epidemiological causality.

    Science.gov (United States)

    Morabia, Alfredo

    2005-01-01

    Epidemiological methods, which combine population thinking and group comparisons, can primarily identify causes of disease in populations. There is therefore a tension between our intuitive notion of a cause, which we want to be deterministic and invariant at the individual level, and the epidemiological notion of causes, which are invariant only at the population level. Epidemiologists have given heretofore a pragmatic solution to this tension. Causal inference in epidemiology consists in checking the logical coherence of a causality statement and determining whether what has been found grossly contradicts what we think we already know: how strong is the association? Is there a dose-response relationship? Does the cause precede the effect? Is the effect biologically plausible? Etc. This approach to causal inference can be traced back to the English philosophers David Hume and John Stuart Mill. On the other hand, the mode of establishing causality, devised by Jakob Henle and Robert Koch, which has been fruitful in bacteriology, requires that in every instance the effect invariably follows the cause (e.g., inoculation of Koch bacillus and tuberculosis). This is incompatible with epidemiological causality which has to deal with probabilistic effects (e.g., smoking and lung cancer), and is therefore invariant only for the population.

  7. Diversidade fenotípica e patogênica de Colletotrichum, agente causal da antracnose em mangueira, e identificação de espécie

    Directory of Open Access Journals (Sweden)

    I.M.R.S. Serra

    2011-03-01

    Full Text Available O presente trabalho teve como objetivo estudar a diversidade fenotípica e patogênica de 40 isolados de Colletotrichum obtidos de mangueira no Nordeste do Brasil e identificar diferentes espécies desse fitopatógeno, agente causal de antracnose, através da análise da seqüência da região ITS do rDNA. Quanto à caracterização morfológica e cultural, as colônias dos isolados apresentaram diversidade em relação à cor e aspecto, sendo mais comum à cor branco-cinza, característica de Colletotrichum gloeosporioides. Não foram observadas variações expressivas na morfologia dos 40 isolados. Os conídios apresentaram-se, predominantemente, hialinos e unicelulares, com formato variando de bastonete para cilíndrico. Todos os isolados produziram apressórios variados em formato e quantidade e apenas 10 isolados apresentaram setas. Para efeito do crescimento micelial e taxa de crescimento foi possível classificar os isolados em sete grupos. Vinte e dois isolados exibiram taxa de crescimento >10mm/dia, considerada típica da espécie C. gloeosporioides. Os isolados foram patogênicos em folhas destacadas de mangueira, induzindo sintomas de antracnose, na forma de manchas escuras levemente deprimidas, e apresentando variações quanto à agressividade. Na identificação específica, baseada na análise da seqüência ITS do DNA ribossomal, 36 isolados amplificaram com o oligonucleotídeos CgInt, específico para C. gloeosporioides e o ITS4, Os isolados CM1, CM4, CM5 e CM10, não amplificaram produtos para nenhum dos oligonucleotídeos específicos, sendo identificados como Colletotrichum spp. Os resultados desse trabalho demonstraram que isolados de Colletotrichum, obtidos de mangueira, apresentam ampla variabilidade morfofisiológica e patogênica. E que, possivelmente, existe mais de uma espécie de Colletotrichum que causa antracnose em mangueira no Nordeste do Brasil.

  8. [Evaluation of the safety of innovative drugs against viruses and infectious agents].

    Science.gov (United States)

    Kobayashi, Tetsu; Yusa, Keisuke; Kawasaki, Nana

    2013-01-01

    Recently, several novel cellular therapy products and biological drugs are being developed to treat various previously untreatable diseases. One of the most important issues regarding these innovations is how to ensure safety over infectious agents, including viruses and prions, in the earliest treatments with these products. The object of this study is a risk assessment of cases of human infectious with the agents and to present a sample risk management plan based on a collaboration among the National Institute of Health Sciences, universities, marketing authorization holders, and scientific societies. There are three subjects of study: (1) the viral safety of cellular therapy products, (2) the viral safety of biological drugs, and (3) the safety of prions. In this report, we describe the objects of the study, the project members, the study plan outline, and the ongoing plans. The results of the viral risk identification and the risk analysis of cellular therapy products will also be described, based on a review of the literature and case reports obtained during the first year of this project.

  9. Expression of a synthetic rust fungal virus cDNA in yeast

    Science.gov (United States)

    Mycoviruses are viruses that infect fungi. Recently, mycovirus-like RNAs were sequenced from the fungus Phakopsora pachyrhizi, the causal agent of soybean rust. One of the RNAs appeared to represent a novel mycovirus and was designated Phakopsora pachyrhizi virus 2383 (PpV2383). The genome of PpV...

  10. First report of papaya meleira virus (PMeV) in Mexico | Perez-Brito ...

    African Journals Online (AJOL)

    Papaya meleira virus (PMeV), causal agent of meleira or sticky disease, is a double-stranded RNA (dsRNA) virus which has been previously reported only in Brazil. A study was carried out in order to verify the presence and occurrence of PMeV in Mexico. Latex samples from symptomatic and asymptomatic papaya fruits ...

  11. First report of Sugarcane yellow leaf virus infecting Columbus Grass (Sorghum almum) in Florida

    Science.gov (United States)

    Sugarcane yellow leaf virus (SCYLV) [genus Polerovirus, family Luteoviridae] is the causal agent of sugarcane yellow leaf disease. SCYLV is widespread in Florida where sugarcane was the only known natural host of this virus. During spring 2015, we collected (leaves or stalks) and tested several gras...

  12. Hymenoscyphus fraxineus vs. Hymenoscyphus albidus – A comparative light microscopic study on the causal agent of European ash dieback and related foliicolous, stroma-forming species

    Science.gov (United States)

    Baral, Hans-Otto; Bemmann, Martin

    2014-01-01

    Five species of Hymenoscyphus that fruit on black stromatized parts of dead leaves of deciduous trees are presented, giving details on their morphological and ecological characteristics. Several of these species have previously been misplaced in rutstroemiaceous genera because of the presence of a substratal stroma. However, the heteropolar, scutuloid ascospores with an often hook-like lateral protrusion at the rounded apex and the ascus apical ring of the Hymenoscyphus-type represent two reliable morphological characteristics that, together with molecular data, provide clear evidence for their placement in the genus Hymenoscyphus (Helotiaceae). Among the species treated is Hymenoscyphus fraxineus (=Hymenoscyphus pseudoalbidus), the causal agent of the European ash dieback disease. Since 1992 this species started within Europe to replace the rather uncommon Hymenoscyphus albidus, which is likewise confined to leaves of Fraxinus. Hy. fraxineus has been recorded already since 1990 in Eastern Asia (Japan, Korea, northeast of China), where it had been initially misidentified as Lambertella albida (≡Hy. albidus). In these regions, it occurs as a harmless saprotroph on Fraxinus mandshurica and Fraxinus rhynchophylla, suggesting that those populations are native while the European ash dieback disease has a recent Eastern Asiatic origin. The distinctly higher genetic diversity found in Japanese Hy. fraxineus in contrast to European Hy. fraxineus supports this view. Genetic similarities between Japanese Hy. fraxineus and European Hy. albidus suggest that also Hy. albidus might be a descendant of Asian Hy. fraxineus, though having invaded Europe much earlier. However, consistent genetic deviation between European and Asian Hy. fraxineus at two nucleotide positions of the ITS region indicates that the European ash disease originates from a region different from the presently known areas in Eastern Asia. Our results underline the importance of detailed morphological studies

  13. Detection of beet soil-borne virus and beet virus Q in sugarbeet in Greece

    NARCIS (Netherlands)

    Pavli, R.; Prins, M.; Skaracis, G.N.

    2010-01-01

    Sugar beet plants with typical rhizomania symptoms were collected from the five major cultivation zones of Greece. The presence of Beet necrotic yellow vein virus (BNYVV), the primary causal agent of the disease, was ascertained by DAS-ELISA in 38 out of 40 fields surveyed and the positive samples

  14. Host-Targeting Agents to Prevent and Cure Hepatitis C Virus Infection.

    Science.gov (United States)

    Zeisel, Mirjam B; Crouchet, Emilie; Baumert, Thomas F; Schuster, Catherine

    2015-11-02

    Chronic hepatitis C virus (HCV) infection is a major cause of liver cirrhosis and hepatocellular carcinoma (HCC) which are leading indications of liver transplantation (LT). To date, there is no vaccine to prevent HCV infection and LT is invariably followed by infection of the liver graft. Within the past years, direct-acting antivirals (DAAs) have had a major impact on the management of chronic hepatitis C, which has become a curable disease in the majority of DAA-treated patients. In contrast to DAAs that target viral proteins, host-targeting agents (HTAs) interfere with cellular factors involved in the viral life cycle. By acting through a complementary mechanism of action and by exhibiting a generally higher barrier to resistance, HTAs offer a prospective option to prevent and treat viral resistance. Indeed, given their complementary mechanism of action, HTAs and DAAs can act in a synergistic manner to reduce viral loads. This review summarizes the different classes of HTAs against HCV infection that are in preclinical or clinical development and highlights their potential to prevent HCV infection, e.g., following LT, and to tailor combination treatments to cure chronic HCV infection.

  15. Acción inhibitoria de una cepa de Zymomonas mobilis mobilis aislada de caña de azúcar sobre Xanthomonas citri subsp. citri, agente causal de la cancrosis de los cítricos Inhibition of Xanthomonas citri subsp. citri, causal agent of citrus canker, by a strain of Zymomonas mobilis mobilis isolated from sugarcane

    Directory of Open Access Journals (Sweden)

    María E. Romero

    2008-06-01

    a wide range of microorganisms pathogenic to man, animals, and plants. An important problem to solve with antimicrobial treatments is the development of resistance in these microorganisms, including phytopathogenic bacteria, to the currently used active ingredients. In this study, antagonism tests with cells (cross-streaking and cell-free culture supernatants (CCS (agar diffusion test from Zm cultures, isolated from sugarcane juice in Tucumán, were carried out, measuring activity against Xanthomonas citri subsp. citri (Xcc, the causal agent of citrus canker. Xcc isolates sensitive (Xc and resistant (Xcr to copper pesticides were included in these tests. Results showed that indicator bacteria were completely inhibited by cells of Zm, which had a bactericide effect. Both Xc and Xcr were sensitive to the CCS in the agar diffusion method. Previous studies had revealed the deleterious effects of metabolites from Zm on cell membranes of E. coli AB1133, inhibiting the respiration of the bacteria inmediately after CCS addition. On the basis of these results, the effects of CCS on Xcc respiration were studied, verifyng a similar response. This would indicate that the site of action of these antimicrobial compounds is also located at the cell membrane of the bacteria under study. Based on these results, additional studies are suggested to evaluate Zm-derived products on the control of diseases that affect economically important crops, such as citrus canker.

  16. Nuclear polyhedrosis virus as a biological control agent for Malacosoma americanum (Lepidoptera: Lasiocampidae)

    Science.gov (United States)

    R.A. Progar; M.J. Rinella; D. Fekedulegn; L. Butler

    2010-01-01

    In addition to damaging trees, the eastern tent caterpillar is implicated in early fetal loss and late-term abortion in horses. In a field study, we evaluated the potential biological control of the caterpillar using eastern tent caterpillar nuclear polyhedrosis virus (ETNPV), a naturally occurring virus that is nearly species-specific. Egg masses were hatched and...

  17. Oryctes virus--time for a new look at a useful biocontrol agent.

    Science.gov (United States)

    Jackson, Trevor A; Crawford, Allan M; Glare, Travis R

    2005-05-01

    The introduction of Oryctes virus into outbreak areas of the rhinoceros beetle, Oryctes rhinoceros (Coleoptera: Scarabaeidae), has been a major success for "classical" biocontrol with a virus and has led to a dramatic reduction in palm damage in many areas of the Asia/Pacific region. In recent years, however, there have been new reports of high levels of rhinoceros beetle damage to palms. Damage has been especially intense in SE Asia following the introduction of no-burn polices for land clearance and replanting, but outbreaks have also been reported from some Pacific Islands where control seems to have diminished over time. SE Asian studies show that there is considerable genetic variation among endemic Oryctes virus isolates and studies in new island release areas have shown rapid evolution of the virus. The consequences of such genetic variation are in need of further study. Furthermore, the taxonomic position of the virus is unclear, with its removal from the Baculoviridae to an "unassigned' virus, reflecting its novel characteristics. Genomic sequencing could help resolve the taxonomy of the virus and provide a basis for studying strain variation. Oryctes virus has achieved wide success in the past without the benefit of molecular analysis and identification techniques. In order to fully take advantage of this unique pathogen for protection of palms, a renewed, coordinated effort centered on genetic selection and distribution of effective strains is required.

  18. Molecular characterization of potato virus X : development of detection probes and identification of the resistance-breaking capacity of strain HB

    NARCIS (Netherlands)

    Querci, M.

    1993-01-01

    One of the principal threats to potato production is the high susceptibility of this food crop to diseases, the causal agents including bacteria, fungi, mycoplasmas, nematodes, viruses and viroids. In particular, close to 30 different viruses, and one viroid, are known to infect potato

  19. Viruses as Sole Causative Agents of Severe Acute Respiratory Tract Infections in Children.

    Science.gov (United States)

    Moesker, Fleur M; van Kampen, Jeroen J A; van Rossum, Annemarie M C; de Hoog, Matthijs; Koopmans, Marion P G; Osterhaus, Albert D M E; Fraaij, Pieter L A

    2016-01-01

    Respiratory syncytial virus (RSV) and influenza A viruses are known to cause severe acute respiratory tract infections (SARIs) in children. For other viruses like human rhinoviruses (HRVs) this is less well established. Viral or bacterial co-infections are often considered essential for severe manifestations of these virus infections. The study aims at identifying viruses that may cause SARI in children in the absence of viral and bacterial co-infections, at identifying disease characteristics associated with these single virus infections, and at identifying a possible correlation between viral loads and disease severities. Between April 2007 and March 2012, we identified children (acute respiratory tract infection (ARTI) (controls). Data were extracted from the clinical and laboratory databases of our tertiary care paediatric hospital. Patient specimens were tested for fifteen respiratory viruses with real-time reverse transcriptase PCR assays and we selected patients with a single virus infection only. Typical bacterial co-infections were considered unlikely to have contributed to the PICU or MC admission based on C-reactive protein-levels or bacteriological test results if performed. We identified 44 patients admitted to PICU with SARI and 40 patients admitted to MC with ARTI. Twelve viruses were associated with SARI, ten of which were also associated with ARTI in the absence of typical bacterial and viral co-infections, with RSV and HRV being the most frequent causes. Viral loads were not different between PICU-SARI patients and MC-ARTI patients. Both SARI and ARTI may be caused by single viral pathogens in previously healthy children as well as in children with a medical history. No relationship between viral load and disease severity was identified.

  20. Zika virus causes microcephaly? Prophylaxis and treatment are more urgent as the causal relationship is sure%寨卡病毒引发小头症?关系越确定,防治越迫切!

    Institute of Scientific and Technical Information of China (English)

    汪小欢; 邹鹏; 黎媛; 陆路

    2017-01-01

    自2015年初至今,寨卡病毒(Zika virus,ZIKV)以巴西为首先后在数十个国家和地区暴发流行.几乎同时,与日俱增的小头症患儿使全球对此陷入警惕状态.目前,全球正在积极探索ZIKV感染所引发的各种神经系统疾病.在越来越多证据表明在细胞水平和动物模型中ZIKV能直接损伤胚胎脑部发育的同时,ZIKV感染者的防治需求也越来越迫切.本文从ZIKV的流行病学、与小头畸形因果关系的研究进展及其预防疫苗和治疗药物的研究现状等方面进行概述.%Since early 2015, Zika virus has caused severe epidemic outbreaks, which started from Brazil involving dozens of regions and countries successively, and contemporaneously growing infants with microcephaly have made the whole global alert against Zika virus.A variety of potential neurological disorders caused by Zika virus infection are under exploring worldwide.The need of treatments for infectors is more and more urgent because of increasing evidences indicating that Zika virus is able to impair the brain development of the embryo in cellular level and animal model.This review will summarize recent research achievements concerning epidemiology and advances among causal relationship with microcephaly, potential preventive vaccines and therapeutic drugs of Zika virus.

  1. Viruses and Multiple Sclerosis

    Science.gov (United States)

    Virtanen, Jussi Oskari; Jacobson, Steve

    2016-01-01

    Multiple sclerosis (MS) is a heterogeneous disease that develops as an interplay between the immune system and environmental stimuli in genetically susceptible individuals. There is increasing evidence that viruses may play a role in MS pathogenesis acting as these environmental triggers. However, it is not known if any single virus is causal, or rather several viruses can act as triggers in disease development. Here, we review the association of different viruses to MS with an emphasis on two herpesviruses, Epstein-Barr virus (EBV) and human herpesvirus 6 (HHV-6). These two agents have generated the most impact during recent years as possible co-factors in MS disease development. The strongest argument for association of EBV with MS comes from the link between symptomatic infectious mononucleosis and MS and from seroepidemiological studies. In contrast to EBV, HHV-6 has been found significantly more often in MS plaques than in MS normal appearing white matter or non-MS brains and HHV-6 re-activation has been reported during MS clinical relapses. In this review we also suggest new strategies, including the development of new infectious animal models of MS and antiviral MS clinical trials, to elucidate roles of different viruses in the pathogenesis of this disease. Furthermore, we introduce the idea of using unbiased sequence-independent pathogen discovery methodologies, such as next generation sequencing, to study MS brain tissue or body fluids for detection of known viral sequences or potential novel viral agents. PMID:22583435

  2. Causally nonseparable processes admitting a causal model

    International Nuclear Information System (INIS)

    Feix, Adrien; Araújo, Mateus; Brukner, Caslav

    2016-01-01

    A recent framework of quantum theory with no global causal order predicts the existence of ‘causally nonseparable’ processes. Some of these processes produce correlations incompatible with any causal order (they violate so-called ‘causal inequalities’ analogous to Bell inequalities ) while others do not (they admit a ‘causal model’ analogous to a local model ). Here we show for the first time that bipartite causally nonseparable processes with a causal model exist, and give evidence that they have no clear physical interpretation. We also provide an algorithm to generate processes of this kind and show that they have nonzero measure in the set of all processes. We demonstrate the existence of processes which stop violating causal inequalities but are still causally nonseparable when mixed with a certain amount of ‘white noise’. This is reminiscent of the behavior of Werner states in the context of entanglement and nonlocality. Finally, we provide numerical evidence for the existence of causally nonseparable processes which have a causal model even when extended with an entangled state shared among the parties. (paper)

  3. Bleeding Sap and Old Wood Are the Two Main Sources of Contamination of Merging Organs of Vine Plants by Xylophilus ampelinus, the Causal Agent of Bacterial Necrosis

    OpenAIRE

    Grall, S.; Roulland, C.; Guillaumès, J.; Manceau, C.

    2005-01-01

    The spatial distribution of vine plants contaminated by Xylophilus ampelinus, the agent responsible for bacterial necrosis, was studied over a 5-year period within two vineyards in the Cognac area. Both vineyards were planted with Vitis vinifera cv. Ugni blanc but were different in age and agronomic location. The emission of X. ampelinus in contaminated bleeding sap was observed during vine sprouting. Contaminated bleeding sap is an important source of inoculum for external contamination due ...

  4. Glucanases and Chitinases as Causal Agents in the Protection of Acacia Extrafloral Nectar from Infestation by Phytopathogens1[W][OA

    Science.gov (United States)

    González-Teuber, Marcia; Pozo, María J.; Muck, Alexander; Svatos, Ales; Adame-Álvarez, Rosa M.; Heil, Martin

    2010-01-01

    Nectars are rich in primary metabolites and attract mutualistic animals, which serve as pollinators or as an indirect defense against herbivores. Their chemical composition makes nectars prone to microbial infestation. As protective strategy, floral nectar of ornamental tobacco (Nicotiana langsdorffii × Nicotiana sanderae) contains “nectarins,” proteins producing reactive oxygen species such as hydrogen peroxide. By contrast, pathogenesis-related (PR) proteins were detected in Acacia extrafloral nectar (EFN), which is secreted in the context of defensive ant-plant mutualisms. We investigated whether these PR proteins protect EFN from phytopathogens. Five sympatric species (Acacia cornigera, A. hindsii, A. collinsii, A. farnesiana, and Prosopis juliflora) were compared that differ in their ant-plant mutualism. EFN of myrmecophytes, which are obligate ant-plants that secrete EFN constitutively to nourish specialized ant inhabitants, significantly inhibited the growth of four out of six tested phytopathogenic microorganisms. By contrast, EFN of nonmyrmecophytes, which is secreted only transiently in response to herbivory, did not exhibit a detectable inhibitory activity. Combining two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis with nanoflow liquid chromatography-tandem mass spectrometry analysis confirmed that PR proteins represented over 90% of all proteins in myrmecophyte EFN. The inhibition of microbial growth was exerted by the protein fraction, but not the small metabolites of this EFN, and disappeared when nectar was heated. In-gel assays demonstrated the activity of acidic and basic chitinases in all EFNs, whereas glucanases were detected only in EFN of myrmecophytes. Our results demonstrate that PR proteins causally underlie the protection of Acacia EFN from microorganisms and that acidic and basic glucanases likely represent the most important prerequisite in this defensive function. PMID:20023149

  5. Hepatitis C virus cell-cell transmission and resistance to direct-acting antiviral agents

    DEFF Research Database (Denmark)

    Xiao, Fei; Fofana, Isabel; Heydmann, Laura

    2014-01-01

    Hepatitis C virus (HCV) is transmitted between hepatocytes via classical cell entry but also uses direct cell-cell transfer to infect neighboring hepatocytes. Viral cell-cell transmission has been shown to play an important role in viral persistence allowing evasion from neutralizing antibodies....... In contrast, the role of HCV cell-cell transmission for antiviral resistance is unknown. Aiming to address this question we investigated the phenotype of HCV strains exhibiting resistance to direct-acting antivirals (DAAs) in state-of-the-art model systems for cell-cell transmission and spread. Using HCV...... genotype 2 as a model virus, we show that cell-cell transmission is the main route of viral spread of DAA-resistant HCV. Cell-cell transmission of DAA-resistant viruses results in viral persistence and thus hampers viral eradication. We also show that blocking cell-cell transmission using host...

  6. H3N2 Virus as Causative Agent of ARDS Requiring Extracorporeal Membrane Oxygenation Support

    Directory of Open Access Journals (Sweden)

    Adriano Peris

    2014-01-01

    Full Text Available Pandemic influenza virus A(H1N1 2009 was associated with a higher risk of viral pneumonia in comparison with seasonal influenza viruses. The influenza season 2011-2012 was characterized by the prevalent circulation of influenza A(H3N2 viruses. Whereas most H3N2 patients experienced mild, self-limited influenza-like illness, some patients were at increased risk for influenza complications because of age or underlying medical conditions. Cases presented were patients admitted to the Intensive Care Unit (ICU of ECMO referral center (Careggi Teaching Hospital, Florence, Italy. Despite extracorporeal membrane oxygenation treatment (ECMO, one patient with H3N2-induced ARDS did not survive. Our experience suggests that viral aetiology is becoming more important and hospitals should be able to perform a fast differential diagnosis between bacterial and viral aetiology.

  7. Inhibitory effect of gut bacteria from the Japanese honey bee, Apis cerana japonica, against Melissococcus plutonius, the causal agent of European foulbrood disease

    Science.gov (United States)

    Wu, Meihua; Sugimura, Yuya; Iwata, Kyoko; Takaya, Noriko; Takamatsu, Daisuke; Kobayashi, Masaru; Taylor, DeMar; Kimura, Kiyoshi; Yoshiyama, Mikio

    2014-01-01

    Abstract European foulbrood is a contagious bacterial disease of honey bee larvae. Studies have shown that the intestinal bacteria of insects, including honey bees, act as probiotic organisms. Microbial flora from the gut of the Japanese honey bee, Apis cerana japonica F. (Hymenoptera: Apidae) , were characterized and evaluated for their potential to inhibit the growth of Melissococcus plutonius corrig. (ex White) Bailey and Collins (Lactobacillales: Enterococcaceae) , the causative agent of European foulbrood. Analysis of 16S rRNA gene sequences from 17 bacterial strains isolated by using a culture-dependent method revealed that most isolates belonged to Bacillus, Staphylococcus, and Pantoea. The isolates were screened against the pathogenic bacterium M. plutonius by using an in vitro growth inhibition assay, and one isolate (Acja3) belonging to the genus Bacillus exhibited inhibitory activity against M. plutonius. In addition, in vivo feeding assays revealed that isolate Acja3 decreased the mortality of honey bee larvae infected with M plutonius, suggesting that this bacterial strain could potentially be used as a probiotic agent against European foulbrood. PMID:25368073

  8. Phenotypic and molecular characterization of the causal agent of chafer beetle mortality in the wheat fields of the Kurdistan province, Iran

    Directory of Open Access Journals (Sweden)

    Karimi Keivan

    2015-07-01

    Full Text Available We report the first case of chafer beetle [Anisoplia austriaca (Herbst 1783] mortality caused by Actinomucor elegans var. elegans in wheat fields of the Kurdistan province, Iran. For three years, dead larvae of Anisoplia austriaca were collected from wheat fields of the Kurdistan province. Similar isolates of a fast-growing fungus were recovered from all samples. The fungal isolates were identified as A. elegans var. elegans based on morphological and cultural characteristics. The identity of the species was further confirmed using sequence data of the ITS (Internal Transcribed Spacer region of ribosomal DNA. Koch’s postulates were fulfilled by the inoculation of the larvae of A. austriaca and Galleria mellonella (Linnaeus, 1758 (as the model insect using the spore suspension of A. elegans var. elegans. The viability of sporangiospores was evaluated using a spore dilution technique on germination medium. The results on the pathogenicity (100% mortality in A. austriaca larvae and viability tests (germination: 95.45% demonstrated that A. elegans var. elegans can be considered as a potential biocontrol agent against the chafer beetle. Field experiments are still required to evaluate the capacity of A. elegans as a biological control agent.

  9. Evaluación a nivel de laboratorio del efecto de 7 extractos vegetales para el control de Colletotrichum sp agente causal de la antracnosis en el cultivo de tomate de árbol - Evaluación a nivel de laboratorio del efecto de 7 extractos vegetales para el control de Colletotrichum sp agente causal de la antracnosis en el cultivo de tomate de árbol

    Directory of Open Access Journals (Sweden)

    Christian Andrei Chacin Zambrano

    2013-08-01

    Full Text Available Was evaluated in the laboratory the effect of seven plant extracts of Neem leaves and fruit (Azadirachta indica leaves of lemon grass (Swinglea glutinosa, leaves of papaya (Carica papaya, Pringamosa leaves (Urtica dioica, eucalyptus leaves (Eucalyptus camaldulensis Dehn fruits of garlic (Allium sativum L. and fruits of pepper (Capsicum annuum in the control of the fungus Colletotrichum sp causal agent of anthracnose in tomato crop tree (Cyphomandra betacea. The pathogen was isolated on PDA medium from tomato fruit tree, the extracts were obtained taking into account the process by (Marin, et. Al 2007, which consists of chopping and blending plant material deposited in plastic bucket, add water ratio 2.5:1 (water: sample processed, vol.: w, subjecting to fermentation for 24 hours. The produto was filtered using sterile gauze and package them for further evaluation. The concentrations of the treatments that worked were 25, 50, 75 and 100% of the infectious agent, determining the degree of inhibition of the pathogen in Petri dishes. The best results were obtained with the application of eucalyptus leaves, since its effect was 100% at all concentrations, without neglecting the fruits of the Neem and garlic with inhibition percentages of 75 and 60% respectively, had a behavior directly proportional to the concentrations used, since the greater the amount of extract the inhibitory effect was better in this case 75% and 100%.

  10. Causal reasoning in physics

    CERN Document Server

    Frisch, Mathias

    2014-01-01

    Much has been written on the role of causal notions and causal reasoning in the so-called 'special sciences' and in common sense. But does causal reasoning also play a role in physics? Mathias Frisch argues that, contrary to what influential philosophical arguments purport to show, the answer is yes. Time-asymmetric causal structures are as integral a part of the representational toolkit of physics as a theory's dynamical equations. Frisch develops his argument partly through a critique of anti-causal arguments and partly through a detailed examination of actual examples of causal notions in physics, including causal principles invoked in linear response theory and in representations of radiation phenomena. Offering a new perspective on the nature of scientific theories and causal reasoning, this book will be of interest to professional philosophers, graduate students, and anyone interested in the role of causal thinking in science.

  11. Theories of Causality

    Science.gov (United States)

    Jones, Robert

    2010-03-01

    There are a wide range of views on causality. To some (e.g. Karl Popper) causality is superfluous. Bertrand Russell said ``In advanced science the word cause never occurs. Causality is a relic of a bygone age.'' At the other extreme Rafael Sorkin and L. Bombelli suggest that space and time do not exist but are only an approximation to a reality that is simply a discrete ordered set, a ``causal set.'' For them causality IS reality. Others, like Judea Pearl and Nancy Cartwright are seaking to build a complex fundamental theory of causality (Causality, Cambridge Univ. Press, 2000) Or perhaps a theory of causality is simply the theory of functions. This is more or less my take on causality.

  12. Functional and biophysical studies on four ceratoplatanins from the fungus Moniliophthora perniciosa, causal agent of the Witche's broom disease

    Energy Technology Data Exchange (ETDEWEB)

    Barsottini, M.; Zaparoli, G.; Garcia, O.; Pereira, G.A.G. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil); Oliveira, J.F.; Tiezzi, H.O.; Ambrosio, A.L.B.; Dias, S.M.G. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil)

    2012-07-01

    Full text: Ceratoplatanin (CP) is a secreted protein of 12.4 kDa initially identified in culture filtrates of the disease ascomycete Ceratocystis fimbriata f. sp. platani, etiological agent of the canker stain disease. CP is also the founding member of the namesake protein family, which contains fungal-secreted proteins involved in various stages of the host-fungus interaction and may act as phytotoxins or elicitors of defense response. Besides the low molecular weight, CPs have a high percentage of hydrophobic residues and share two conserved intramolecular disulfide bonds. It has been suggested that CPs have important physiological functions, including interaction with cell wall or cell membrane and manipulation of the host's defense system. Furthermore, a recent work showed that the ceratoplatanin from C. fimbriata has some degree of affinity for the saccharide 4-N-acetylglucosamine. However, its precise molecular function remains elusive. Five putative CPs have been identified in Moniliophthora perniciosa a basidiomycete fungus responsible for great economic losses in cocoa industry in the form of Witches' broom disease (WBD) , four of which had their crystal structures resolved by our group. In this work we report biophysical and functional studies on these MpCPs aiming at understanding their role and importance during the WBD progression. (author)

  13. Bleeding sap and old wood are the two main sources of contamination of merging organs of vine plants by Xylophilus ampelinus, the causal agent of bacterial necrosis.

    Science.gov (United States)

    Grall, S; Roulland, C; Guillaumès, J; Manceau, C

    2005-12-01

    The spatial distribution of vine plants contaminated by Xylophilus ampelinus, the agent responsible for bacterial necrosis, was studied over a 5-year period within two vineyards in the Cognac area. Both vineyards were planted with Vitis vinifera cv. Ugni blanc but were different in age and agronomic location. The emission of X. ampelinus in contaminated bleeding sap was observed during vine sprouting. Contaminated bleeding sap is an important source of inoculum for external contamination due to the high susceptibility of young merging shoots to the pathogen. X. ampelinus emission by bleeding sap was not affected by the age of the plants or the location of the vineyards. However, its emission was irregular with time, and it varied between two fruit canes from individual plants and between plants as well as between years. Moreover, the two vineyards appeared to be entirely contaminated. Consequently, the behavior of the pathogen is not predictable. The distribution of the pathogen inside vine plant organs was analyzed through the four growing seasons. The old wood was contaminated throughout the year and constituted a stock inoculum for endophytic contamination of crude sap during the winter and the spring. Despite the fact that most of the young green shoots were contaminated in May, X.ampelinus was not found in green shoots in June and September, refuting the hypothesis of an epiphytic life of the pathogen under natural conditions. Although all plants were entirely contaminated in both vineyards, symptoms were rare and were observed on different plants each year.

  14. Causality in Science

    Directory of Open Access Journals (Sweden)

    Cristina Puente Águeda

    2011-10-01

    Full Text Available Causality is a fundamental notion in every field of science. Since the times of Aristotle, causal relationships have been a matter of study as a way to generate knowledge and provide for explanations. In this paper I review the notion of causality through different scientific areas such as physics, biology, engineering, etc. In the scientific area, causality is usually seen as a precise relation: the same cause provokes always the same effect. But in the everyday world, the links between cause and effect are frequently imprecise or imperfect in nature. Fuzzy logic offers an adequate framework for dealing with imperfect causality, so a few notions of fuzzy causality are introduced.

  15. Efeito inibitório de extratos vegetais sobre Colletotrichum gloeosporioides - agente causal da podridão de frutos de mamoeiro

    Directory of Open Access Journals (Sweden)

    Ribeiro Luiz Fernando

    1999-01-01

    Full Text Available Extratos aquosos foram obtidos a partir de bulbilhos de alho, folhas de hortelã e mamona e frutos de pimenta. Após a incorporação destes extratos em BDA, obtendo-se concentrações de 100, 200, 500, 1000, 5000 e 10000 ppm, foi avaliado o crescimento e a produção de conídios de um isolado de Colletotrichum gloeosporioides, agente de podridão em frutos de mamoeiro. Os resultados demonstraram o efeito inibitório dos diferentes extratos a partir da concentração de 200 ppm. O extrato de alho inibiu o crescimento micelial, em porcentagens variáveis de 5,3 a 67,6%, porém não atuou de modo expressivo sobre a produção de conídios. Em contraposição, os extratos de hortelã, mamona e pimenta promoveram inibição menos acentuada do crescimento de micélio, porém reduziram drasticamente a produção de conídios em níveis variáveis de 41 a 84%, de acordo com as concentrações crescentes dos mesmos. As propriedades fungitóxicas detectadas nos extratos utilizados no ensaio evidenciaram o uso potencial dos mesmos como alternativa aos métodos físicos e químicos convencionalmente usados para o controle da doença.

  16. Radiation sensitivity of bacteria and virus in porcine xenoskin for dressing agent

    International Nuclear Information System (INIS)

    Jo, Eu-Ri; Jung, Pil-Mun; Choi, Jong-il; Lee, Ju-Woon

    2012-01-01

    In this study, gamma irradiation sensitivities of bacteria and viruses in porcine skin were evaluated to establish the optimum sterilization condition for the dressing material and a xenoskin graft. Escherichia coli and Bacillus subtilis were used as model pathogens and inoculated at 10 6 –10 7 log CFU/g. As model viruses, porcine parvovirus (PPV), bovine viral diarrhea virus (BVDV), and poliovirus were used and inoculated at 10 5 –10 6 TCID 50 /g into porcine skin. The D 10 value of E. coli was found to be 0.25±0.1 kGy. B. subtilis endospores produced under stressful environmental conditions showed lower radiation sensitivity as D 10 was 3.88±0.3 kGy in porcine skin. The D 10 values of PPV, BVDV, and poliovirus were found to be 1.73±0.2, 3.81±0.2, and 6.88±0.3 kGy, respectively. These results can offer the basic information required for inactivating pathogens by gamma irradiation and achieving dressing material and porcine skin grafts.

  17. Evaluation of Human Papilloma Virus Communicative Education Strategies: A Pilot Screening Study for Cervical Cancer

    Science.gov (United States)

    Barrera-Clavijo, Lizeth K.; Wiesner-Ceballos, Carolina; Rincón-Martínez, Lina M.

    2016-01-01

    Background: High-risk human papilloma virus (HR-HPV) is highly prevalent in sexually active men and women; HR-HPV has been classified as a sexually transmitted infection (STI) and as a necessary, but not sufficient, causal agent for cervical cancer. Women who test positive for HPV often experience serious psychosocial consequences such as fear,…

  18. El virus de la D.V.B. como agente contaminante en cultivo de tejidos animales

    OpenAIRE

    Víctor J. Vera A.; Jorge L. Parra A.; Gloria C. Ramírez N.; Luis C. Villamil

    1992-01-01

    El Pestisvirus que produce la Diarrea Viral Bovina (V.D.V.B.), ocasiona problemas reproductivos en el ganado vacuno y se encuentra ampliamente difundido en el país. La presencia de cepas no citopatogénicas del mismo, las cuales normalmente no se evidencian en los cultivos celulares contaminados con éste virus, han constituido un Iimitante para el establecimiento y mantenimiento de cultivos primarios y líneas celulares libres del V.D.V.B., para uso rutinario en actividades diagnósticas o inves...

  19. Reasoning with Causal Cycles

    Science.gov (United States)

    Rehder, Bob

    2017-01-01

    This article assesses how people reason with categories whose features are related in causal cycles. Whereas models based on causal graphical models (CGMs) have enjoyed success modeling category-based judgments as well as a number of other cognitive phenomena, CGMs are only able to represent causal structures that are acyclic. A number of new…

  20. Onicomicosis: epidemiología, agentes causales y evaluación de los métodos diagnósticos de laboratorio Onychomycoses: epidemiology, causative agents and assessment of diagnostic laboratory methods

    OpenAIRE

    Javier R Nazar; Paula E Gerosa; Osvaldo A Díaz

    2012-01-01

    Desde marzo de 2007 hasta marzo de 2011 se estudiaron prospectivamente 414 pacientes con onicodistrofias en un laboratorio privado de Esquel. La prevalencia de onicomicosis de pie fue del 78 %; la de mano, del 58 %. Los principales agentes etiológicos fueron Trichophyton rubrum, Candida spp. y Trichophyton mentagrophytes. El desarrollo de dermatofitos prevaleció en las onicopatías de pie y el de Candida spp. en las de uñas de mano (ambos, p < 0,05). En las onicomicosis candidiásicas predomina...

  1. Endophytic bacteria from Piper tuberculatum Jacq.: isolation, molecular characterization, and in vitro screening for the control of Fusarium solani f. sp piperis, the causal agent of root rot disease in black pepper (Piper nigrum L.).

    Science.gov (United States)

    Nascimento, S B; Lima, A M; Borges, B N; de Souza, C R B

    2015-07-06

    Endophytic bacteria have been found to colonize internal tissues in many different plants, where they can have several beneficial effects, including defense against pathogens. In this study, we aimed to identify endophytic bacteria associated with roots of the tropical piperaceae Piper tuberculatum, which is known for its resistance to infection by Fusarium solani f. sp piperis, the causal agent of black pepper (Piper nigrum) root rot disease in the Amazon region. Based on 16S rRNA gene sequence analysis, we isolated endophytes belonging to 13 genera: Bacillus, Paenibacillus, Pseudomonas, Enterobacter, Rhizobium, Sinorhizobium, Agrobacterium, Ralstonia, Serratia, Cupriavidus, Mitsuaria, Pantoea, and Staphylococcus. The results showed that 56.52% of isolates were associated with the phylum Proteobacteria, which comprised α, β, and γ classes. Other bacteria were related to the phylum Firmicutes, including Bacillus, which was the most abundant genus among all isolates. Antagonistic assays revealed that Pt12 and Pt13 isolates, identified as Pseudomonas putida and Pseudomonas sp, respectively, were able to inhibit F. solani f. sp piperis growth in vitro. We describe, for the first time, the molecular identification of 23 endophytic bacteria from P. tuberculatum, among which two Pseudomonas species have the potential to control the pathogen responsible for root rot disease in black pepper in the Amazon region.

  2. Direct-acting antiviral agents against hepatitis C virus and lipid metabolism.

    Science.gov (United States)

    Kanda, Tatsuo; Moriyama, Mitsuhiko

    2017-08-21

    Hepatitis C virus (HCV) infection induces steatosis and is accompanied by multiple metabolic alterations including hyperuricemia, reversible hypocholesterolemia and insulin resistance. Total cholesterol, low-density lipoprotein-cholesterol and triglyceride levels are increased by peginterferon and ribavirin combination therapy when a sustained virologic response (SVR) is achieved in patients with HCV. Steatosis is significantly more common in patients with HCV genotype 3 but interferon-free regimens are not always effective for treating HCV genotype 3 infections. HCV infection increases fatty acid synthase levels, resulting in the accumulation of fatty acids in hepatocytes. Of note, low-density lipoprotein receptor, scavenger receptor class B type I and Niemann-Pick C1-like 1 proteins are candidate receptors that may be involved in HCV. They are also required for the uptake of cholesterol from the external environment of hepatocytes. Among HCV-infected patients with or without human immunodeficiency virus infection, changes in serum lipid profiles are observed during interferon-free treatment and after the achievement of an SVR. It is evident that HCV affects cholesterol metabolism during interferon-free regimens. Although higher SVR rates were achieved with interferon-free treatment of HCV, special attention must also be paid to unexpected adverse events based on host metabolic changes including hyperlipidemia.

  3. Onicomicosis: epidemiología, agentes causales y evaluación de los métodos diagnósticos de laboratorio Onychomycoses: epidemiology, causative agents and assessment of diagnostic laboratory methods

    Directory of Open Access Journals (Sweden)

    Javier R Nazar

    2012-03-01

    Full Text Available Desde marzo de 2007 hasta marzo de 2011 se estudiaron prospectivamente 414 pacientes con onicodistrofias en un laboratorio privado de Esquel. La prevalencia de onicomicosis de pie fue del 78 %; la de mano, del 58 %. Los principales agentes etiológicos fueron Trichophyton rubrum, Candida spp. y Trichophyton mentagrophytes. El desarrollo de dermatofitos prevaleció en las onicopatías de pie y el de Candida spp. en las de uñas de mano (ambos, p Since March 2007 to March 2011, 414 patients with onychopathies were prospectively analyzed. Prevalence of the toenail and fingernail mycoses was 78 % and 58 %, respectively. The major etiological agents were Trichophyton rubrum, Candida spp. and Trichophyton mentagrophytes. Dermatophytes were more frequently cultured from toenails, whereas Candida spp. from fingernails (both, p < 0.05. In candidal onychomycosis, species different from C. albicans were prevalent. A higher prevalence of toenail and fingernail mycoses, a predominance of T. rubrum in toenails (p < 0.05, and greater positivity in the direct examination (DE and in culture (both, p < 0.05 were more frequently observed in men than in women. The correlation between DE and culture was 68 %. DE and culture yields were associated with a greater size lesion. DE was more effective in onycodystrophies with duration of more than 5 years. Culture positivity was independent of nail affection chronicity.

  4. Rnas inhibidores frente al virus de la inmunodeficiencia humana

    OpenAIRE

    Sánchez Luque, Francisco José

    2013-01-01

    En la presente tesis se describe la generaci??n de peque??as mol??culas de RNA con funci??n inhibidora frente al Virus de la Inmunodeficiencia Humana de Tipo 1 (VIH-1). Este virus es el agente causal del S??ndrome de Inmunodeficiencia Adquirida y perteneciente al g??nero Lentivirus de la familia Retroviridae. El virus presenta una alternancia en cuanto al tipo de material gen??tico en su ciclo de vida, siendo RNA en las part??culas virales y DNA en el provirus (durante la fase de latencia o e...

  5. The mosaic of environment involvement in autoimmunity: the abrogation of viral latency by stress, a non-infectious environmental agent, is an intrinsic prerequisite prelude before viruses can rank as infectious environmental agents that trigger autoimmune diseases.

    Science.gov (United States)

    Temajo, Norbert O; Howard, Neville

    2014-06-01

    An autoimmune disease (AD), organ-specific or systemic, results from an aberrant response in which the protective immune system normally schooled to recognize and destroy invading infectious agents (viruses, etc.) instead fails to distinguish self-antigens and proceeds to attack and destroy the host's organs. There can be familial aggregation in which a single AD may occur in members of a family, or a single family may be afflicted with multiple ADs. Finally, sometimes multiple ADs co-occur in a single individual: the kaleidoscope of autoimmunity. Autoimmunity is a multifactorial process in which genetic, hormonal, immunological and environmental factors act in concert to materialize the mosaic of autoimmunity phenomenon. A genetically primed individual may yet not develop an AD: the contribution by an environmental factor (non-infectious or infectious) is essential for completion of the act. Of the non-infectious factors, stress plays a determinative step in autoimmunity in that it abrogates viral latency and thereby ordains the viruses to qualify as infectious environmental factors that trigger ADs. This is note-worthy as viruses rank first as the most important environmental triggers of ADs. Furthermore, all these viruses experience going through latency. Hence the hypothesis: "The abrogation of viral latency by stress, a non-infectious environmental agent, is an intrinsic prerequisite prelude before viruses can rank as infectious environmental agents that trigger autoimmune diseases". There is collaboration here between non-infectious- and infectious-agent to achieve the cause of autoimmunity. We say viral latency and stress have a covenant: continued perpetration of autoimmunity is dependent on the intervention by stress to reactivate latent infections. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  6. El virus de la D.V.B. como agente contaminante en cultivo de tejidos animales

    Directory of Open Access Journals (Sweden)

    Víctor J. Vera A.

    1992-03-01

    Full Text Available El Pestisvirus que produce la Diarrea Viral Bovina (V.D.V.B., ocasiona problemas reproductivos en el ganado vacuno y se encuentra ampliamente difundido en el país. La presencia de cepas no citopatogénicas del mismo, las cuales normalmente no se evidencian en los cultivos celulares contaminados con éste virus, han constituido un Iimitante para el establecimiento y mantenimiento de cultivos primarios y líneas celulares libres del V.D.V.B., para uso rutinario en actividades diagnósticas o investigativas. El suero fetal bovino (SFB es la fuente usual de contaminación para los cultivos de tejidos animales, dadas las escasas previsiones para el control de su calidad, ya que la recolección y mercadeo del SFB se realiza con criterios artesanales y sin los debidos controles de calidad. Específicamente en el caso del V.D.V.B., se pueden presentar dos situaciones con el SFB: que contenga partículas virales o que posea niveles de anticuerpos contra el virus; en ambos casos se darán problemas en los procedimientos realizados con dichos sueros. Con el fin de controlar las contaminaciones de los cultivos celulares con el VDVB, en el Postgrado de la Facultad de Medicina Veterinaria de la Universidad Nacional, se ha empleado la técnica de Inmunofluorescencia Indirecta (IFl para detectarlas tanto, en el SFB como en diferentes cultivos celulares, obteniéndose para el SFB el 25.8% de positivos de un total de 32 muestras de diferentes orígenes y para los cultivos celulares el 42.8% de positivos de 28 lotes, procedentes de diferente origen animal y centros de investigación, resultados que son comparables con los obtenidos por otros laboratorios internacionales como el National Animal Diseases Laboratory (NADL del Departamento de Agricultura de USA. Dentro de las recomendaciones para la prevención y control del problema en laboratorios de diagnóstico e investigación médica y veterinaria, que empleen tecnologías relacionadas con manejo y

  7. An accelerated soil bait assay for the detection of potato mop top virus in agricultural soil.

    Science.gov (United States)

    Davey, Triona

    2009-01-01

    An accelerated soil bait test can be used to determine whether a field harbours virus-carrying Spongospora subterranea. S. subterranea is the causal agent of powdery scab and also the only vector of potato mop top virus (PMTV). Real-time RT-PCR can detect PMTV RNA in the roots of bait plants after 2 weeks of growth in viruliferous soil. This test may be used to assess the risk of planting potato crops in a particular field.

  8. Causal imprinting in causal structure learning.

    Science.gov (United States)

    Taylor, Eric G; Ahn, Woo-Kyoung

    2012-11-01

    Suppose one observes a correlation between two events, B and C, and infers that B causes C. Later one discovers that event A explains away the correlation between B and C. Normatively, one should now dismiss or weaken the belief that B causes C. Nonetheless, participants in the current study who observed a positive contingency between B and C followed by evidence that B and C were independent given A, persisted in believing that B causes C. The authors term this difficulty in revising initially learned causal structures "causal imprinting." Throughout four experiments, causal imprinting was obtained using multiple dependent measures and control conditions. A Bayesian analysis showed that causal imprinting may be normative under some conditions, but causal imprinting also occurred in the current study when it was clearly non-normative. It is suggested that causal imprinting occurs due to the influence of prior knowledge on how reasoners interpret later evidence. Consistent with this view, when participants first viewed the evidence showing that B and C are independent given A, later evidence with only B and C did not lead to the belief that B causes C. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Verrugas plantares: caracterización de los virus causales y aplicación del láser 1064 nm a su tratamiento

    OpenAIRE

    Planell Mas, Elena de

    2016-01-01

    INTRODUCCIÓN: Las verrugas plantares están provocadas por el virus del papilloma humano (VPH). Se han descrito diferentes genotipos asociados a estas lesiones si bien existen pocos estudios centrados exclusivamente en los genotipos de las verrugas plantares. El diagnóstico generalmente es clínico, aunque actualmente existen métodos diagnósticos basados en la detección del ADN viral como es el caso de la PCR (polymerase chain reaction). Las modalidades de tratamiento de las verrugas so...

  10. Interleukin 37 expression in mice alters sleep responses to inflammatory agents and influenza virus infection

    Directory of Open Access Journals (Sweden)

    Christopher J. Davis

    2017-06-01

    Full Text Available Multiple interactions between the immune system and sleep are known, including the effects of microbial challenge on sleep or the effects of sleep loss on facets of the immune response. Cytokines regulate, in part, sleep and immune responses. Here we examine the role of an anti-inflammatory cytokine, interleukin-37 (IL-37 on sleep in a mouse strain that expresses human IL-37b (IL37tg mice. Constitutive expression of the IL-37 gene in the brains of these mice under resting conditions is low; however, upon an inflammatory stimulus, expression increases dramatically. We measured sleep in three conditions; (a under baseline conditions and after 6 h of sleep loss, (b after bolus intraperitoneal administration of lipopolysaccharide (LPS or IL-1β and (c after intranasal influenza virus challenge. Under baseline conditions, the IL37tg mice had 7% more spontaneous non-rapid eye movement sleep (NREMS during the light period than wild-type (WT mice. After sleep deprivation both WT mice and IL37tg mice slept an extra 21% and 12%, respectively, during the first 6 h of recovery. NREMS responses after sleep deprivation did not significantly differ between WT mice and IL37tg mice. However, in response to either IL-1β or LPS, the increases in time spent in NREMS were about four-fold greater in the WT mice than in the IL37tg mice. In contrast, in response to a low dose of mouse-adapted H1N1 influenza virus, sleep responses developed slowly over the 6 day recording period. By day 6, NREMS increased by 10% and REMS increased by 18% in the IL37tg mice compared to the WT mice. Further, by day 4 IL37tg mice lost less weight, remained more active, and retained their body temperatures closer to baseline values than WT mice. We conclude that conditions that promote IL-37 expression attenuate morbidity to severe inflammatory challenge.

  11. Repeated causal decision making.

    Science.gov (United States)

    Hagmayer, York; Meder, Björn

    2013-01-01

    Many of our decisions refer to actions that have a causal impact on the external environment. Such actions may not only allow for the mere learning of expected values or utilities but also for acquiring knowledge about the causal structure of our world. We used a repeated decision-making paradigm to examine what kind of knowledge people acquire in such situations and how they use their knowledge to adapt to changes in the decision context. Our studies show that decision makers' behavior is strongly contingent on their causal beliefs and that people exploit their causal knowledge to assess the consequences of changes in the decision problem. A high consistency between hypotheses about causal structure, causally expected values, and actual choices was observed. The experiments show that (a) existing causal hypotheses guide the interpretation of decision feedback, (b) consequences of decisions are used to revise existing causal beliefs, and (c) decision makers use the experienced feedback to induce a causal model of the choice situation even when they have no initial causal hypotheses, which (d) enables them to adapt their choices to changes of the decision problem. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

  12. Cynaropicrin: a comprehensive research review and therapeutic potential as an anti- hepatitis C virus agent

    Directory of Open Access Journals (Sweden)

    Mahmoud Fahmi Elsebai

    2016-12-01

    Full Text Available The different pharmacologic properties of plants-containing cynaropicrin, especially artichokes, have been known for many centuries. More recently, cynaropicrin exhibited a potential activity against all genotypes of hepatitis C virus (HCV. Cynaropicrin has also shown a wide range of other pharmacologic properties such as anti-hyperlipidemic, anti-trypanosomal, anti-malarial, antifeedant, antispasmodic, anti-photoaging, and anti-tumor action, as well as activation of bitter sensory receptors, and anti-inflammatory properties (e.g., associated with the suppression of the key pro-inflammatory NF-κB pathway. These pharmacological effects are very supportive factors to its outstanding activity against HCV. Structurally, cynaropicrin might be considered as a potential drug candidate, since it has no violations for the rule of five and its water-solubility could allow formulation as therapeutic injections. Moreover, cynaropicrin is a small molecule that can be easily synthesized and as the major constituent of the edible plant artichoke, which has a history of safe dietary use. In summary, cynaropicrin is a promising bioactive natural product that, with minor hit-to-lead optimization, might be developed as a drug for HCV.

  13. Estudio del virus JC, agente causal de la leucoencafalopatía multifocal progresiva, en pacientes de esclerosis múltiple recurrente-remitente tratados con Natalizumab

    OpenAIRE

    Domínguez Mozo, María Inmaculada

    2013-01-01

    La esclerosis múltiple (EM) es una enfermedad desmielinizante inflamatoria crónica que afecta al sistema nervioso central (SNC) y cuyo origen es presumiblemente autoinmune, siendo en los países desarrollados la segunda causa de discapacidad entre personas jóvenes después de los accidentes de tráfico. Durante los últimos años se han desarrollado, o actualmente están en ensayo clínico, una gran cantidad de fármacos para tratar esta patología. Entre todos ellos cabe destacar natalizumab, u...

  14. Caracterización taxonómica y análisis de la variabilidad del agente causal del cancro del tallo de la soja en Buenos Aires (2005/2007

    Directory of Open Access Journals (Sweden)

    GRIJALBA, P.E

    2011-12-01

    Full Text Available ResumenEl complejo Diaporthe/Phomopsis es un importante grupo de hongos patógenos de la soja. Dentro del mismo, Diaporthe phaseolorum var. caulivora es uno de los agentes causales del cancro del tallo. Veintitrés aislamientos de este hongo, provenientes de diferentes zonas geográficas de la provincia de Buenos Aires, fueron caracterizados morfológica y genéticamente. Los criterios morfológicos fueron tipo y color de micelio; formación del teleomorfo y/o del anamorfo. La identificación molecular fue llevada a cabo utilizando una técnica de restricción de fragmentos de amplificación (PCR-RFLP de la región ITS de ADN ribosomal. Adicionalmente, los productos de amplificación fueron secuenciados y comparados con la información de bancos de datos. Los aislamientos presentaron características morfológicas y patogénicas propias de la variedad, y los patrones de restricción con la enzima Alu I fueron concordantes con la identificación morfológica y con la información de secuencias disponibles. Las reconstrucciones filogenéticas apoyan la idea de que D. meridionalis y D. caulivora son entidades biológicamente aisladas. Los resultados obtenidos confirmaron la utilidad del uso del método de PCR-RFLP para la identificación precisa y rápida de D. caulivora. Por sus características, este método puede ser implementado para análisis de rutina en laboratorios de pequeña y mediana escala.AbstractDiaporthe/Phomopsis is an important group of soybean pathogens. Diaporthe phaseolorum var. caulivora is one of the causal agents of stem canker. Twenty three isolates from different regions from the Province of Buenos Aires were morphologically and genetically characterized and assigned to different taxa within the Diaporthe/Phomopsis complex; diagnostic morphological traits were: mycelium type and color, teleomorph/anamorph occurrence. Molecular characterization was carried out using RFLP analyses of PCR-amplified DNA (PCRRFLP for the

  15. Detection of cucumber green mottle mosaic virus-infected watermelon seeds using short wave infrared (SWIR) hyperspectral imaging system

    Science.gov (United States)

    The cucurbit diseases caused by cucumber green mottle mosaic virus (CGMMV) have led to a serious problem to growers and seed producers because it is difficult to prevent spreading through causal agent of seeds. Conventional detection methods for infected seed such as a biological, serological, and m...

  16. Kalanchoë blossfeldiana, a new host for Sonchus yellow net virus

    OpenAIRE

    Bouwen, I.; Schoen, C.D.; Balen, van, E.; Vlugt, van der, R.A.A.

    2002-01-01

    The agent causing chlorotic spots in Kalanchoë blossfeldiana `Isabella¿ was investigated. A virus isolated from this naturally infected kalanchoë was mechanically transmissible to several indicator plants. Observation of suspension preparations in the electron microscope revealed rhabdovirus-like particles. On the basis of symptoms on indicator plants, serology, electron microscopy, molecular characterisation and back inoculation to K. blossfeldiana 'Isabella', the causal agent was identified...

  17. Development of anti-infectives using phage display: biological agents against bacteria, viruses, and parasites.

    Science.gov (United States)

    Huang, Johnny X; Bishop-Hurley, Sharon L; Cooper, Matthew A

    2012-09-01

    The vast majority of anti-infective therapeutics on the market or in development are small molecules; however, there is now a nascent pipeline of biological agents in development. Until recently, phage display technologies were used mainly to produce monoclonal antibodies (MAbs) targeted against cancer or inflammatory disease targets. Patent disputes impeded broad use of these methods and contributed to the dearth of candidates in the clinic during the 1990s. Today, however, phage display is recognized as a powerful tool for selecting novel peptides and antibodies that can bind to a wide range of antigens, ranging from whole cells to proteins and lipid targets. In this review, we highlight research that exploits phage display technology as a means of discovering novel therapeutics against infectious diseases, with a focus on antimicrobial peptides and antibodies in clinical or preclinical development. We discuss the different strategies and methods used to derive, select, and develop anti-infectives from phage display libraries and then highlight case studies of drug candidates in the process of development and commercialization. Advances in screening, manufacturing, and humanization technologies now mean that phage display can make a significant contribution in the fight against clinically important pathogens.

  18. Field and laboratory evidence that Bungowannah virus, a recently recognised pestivirus, is the causative agent of the porcine myocarditis syndrome (PMC).

    Science.gov (United States)

    Finlaison, Deborah S; King, Katherine R; Frost, Melinda J; Kirkland, Peter D

    2009-05-12

    In 2003 an outbreak of sudden deaths occurred in 2-3-week-old piglets on a piggery in New South Wales, Australia. There was a marked increase in the birth of stillborn piglets and preweaning losses associated with a multifocal non-suppurative myocarditis with myonecrosis. The aim of this study was to review existing data and to undertake further investigations of specimens from naturally infected pigs to provide evidence to support the hypothesis that Bungowannah virus, a recently recognised pestivirus, causes the porcine myocarditis syndrome (PMC). Sera collected from gilts and sows from affected and unaffected units were tested for Bungowannah virus antibody by a peroxidase-linked assay and Bungowannah virus RNA by qRT-PCR in selected cases. Stillborn piglets from affected and an unaffected unit were also tested for Bungowannah virus antibody and RNA. Body fluid IgG levels and the incidence of myocardial lesions in these stillborn piglets are summarised. Tissue sections from stillborn piglets with myocarditis/myonecrosis were examined for Bungowannah virus RNA by in situ hybridisation. A clear temporal association between the occurrence of PMC on a unit or module and exposure to Bungowannah virus was identified by serological tests in both breeding aged animals and stillborn pigs. In addition, at the individual animal level on affected units, Bungowannah virus RNA was detected in stillborn piglets in large amounts by qRT-PCR and in association with myocardial lesions by in situ hybridisation. The examination of field material from cases of PMC by serology, qRT-PCR and in situ hybridisation provides strong indirect evidence that Bungowannah virus is the causative agent for PMC.

  19. Repeated Causal Decision Making

    Science.gov (United States)

    Hagmayer, York; Meder, Bjorn

    2013-01-01

    Many of our decisions refer to actions that have a causal impact on the external environment. Such actions may not only allow for the mere learning of expected values or utilities but also for acquiring knowledge about the causal structure of our world. We used a repeated decision-making paradigm to examine what kind of knowledge people acquire in…

  20. Viscous causal cosmologies

    International Nuclear Information System (INIS)

    Novello, M.; Salim, J.M.; Torres, J.; Oliveira, H.P. de

    1989-01-01

    A set of spatially homogeneous and isotropic cosmological geometries generated by a class of non-perfect is investigated fluids. The irreversibility if this system is studied in the context of causal thermodynamics which provides a useful mechanism to conform to the non-violation of the causal principle. (author) [pt

  1. Causal Analysis After Haavelmo

    Science.gov (United States)

    Heckman, James; Pinto, Rodrigo

    2014-01-01

    Haavelmo's seminal 1943 and 1944 papers are the first rigorous treatment of causality. In them, he distinguished the definition of causal parameters from their identification. He showed that causal parameters are defined using hypothetical models that assign variation to some of the inputs determining outcomes while holding all other inputs fixed. He thus formalized and made operational Marshall's (1890) ceteris paribus analysis. We embed Haavelmo's framework into the recursive framework of Directed Acyclic Graphs (DAGs) used in one influential recent approach to causality (Pearl, 2000) and in the related literature on Bayesian nets (Lauritzen, 1996). We compare the simplicity of an analysis of causality based on Haavelmo's methodology with the complex and nonintuitive approach used in the causal literature of DAGs—the “do-calculus” of Pearl (2009). We discuss the severe limitations of DAGs and in particular of the do-calculus of Pearl in securing identification of economic models. We extend our framework to consider models for simultaneous causality, a central contribution of Haavelmo. In general cases, DAGs cannot be used to analyze models for simultaneous causality, but Haavelmo's approach naturally generalizes to cover them. PMID:25729123

  2. Agency, time and causality

    Directory of Open Access Journals (Sweden)

    Thomas eWidlok

    2014-11-01

    Full Text Available Cognitive Scientists interested in causal cognition increasingly search for evidence from non-WEIRD people but find only very few cross-cultural studies that specifically target causal cognition. This article suggests how information about causality can be retrieved from ethnographic monographs, specifically from ethnographies that discuss agency and concepts of time. Many apparent cultural differences with regard to causal cognition dissolve when cultural extensions of agency and personhood to non-humans are taken into account. At the same time considerable variability remains when we include notions of time, linearity and sequence. The article focuses on ethnographic case studies from Africa but provides a more general perspective on the role of ethnography in research on the diversity and universality of causal cognition.

  3. Non-Causal Computation

    Directory of Open Access Journals (Sweden)

    Ämin Baumeler

    2017-07-01

    Full Text Available Computation models such as circuits describe sequences of computation steps that are carried out one after the other. In other words, algorithm design is traditionally subject to the restriction imposed by a fixed causal order. We address a novel computing paradigm beyond quantum computing, replacing this assumption by mere logical consistency: We study non-causal circuits, where a fixed time structure within a gate is locally assumed whilst the global causal structure between the gates is dropped. We present examples of logically consistent non-causal circuits outperforming all causal ones; they imply that suppressing loops entirely is more restrictive than just avoiding the contradictions they can give rise to. That fact is already known for correlations as well as for communication, and we here extend it to computation.

  4. Enhanced vesicular stomatitis virus (VSVΔ51 targeting of head and neck cancer in combination with radiation therapy or ZD6126 vascular disrupting agent

    Directory of Open Access Journals (Sweden)

    Alajez Nehad M

    2012-06-01

    Full Text Available Abstract Background Head and neck squamous cell carcinoma (HNSCC is the 5th most common cancer worldwide. Locally advanced HNSCC are treated with either radiation or chemo-radiotherapy, but still associated with high mortality rate, underscoring the need to develop novel therapies. Oncolytic viruses have been garnering increasing interest as anti-cancer agents due to their preferential killing of transformed cells. In this study, we evaluated the therapeutic potential of mutant vesicular stomatitis virus (VSVΔ51 against the human hypopharyngeal FaDu tumour model in vitro and in vivo. Results Our data demonstrated high toxicity of the virus against FaDu cells in vitro, which was associated with induction of apoptosis. In vivo, systemic injection of 1 × 109 pfu had minimal effect on tumour growth; however, when combined with two doses of ionizing radiation (IR; 5 Gy each or a single injection of the vascular disrupting agent (ZD6126, the virus exhibited profound suppression of tumour growth, which translated to a prolonged survival in the treated mice. Concordantly, VSVΔ51 combined with ZD6126 led to a significant increase in viral replication in these tumours. Conclusions Our data suggest that the combinations of VSVΔ51 with either IR or ZD6126 are potentially novel therapeutic opportunities for HNSCC.

  5. Sartre's Contingency of Being and Asouzu's Principle of Causality ...

    African Journals Online (AJOL)

    The position of this work is that all contingent beings have a causal agent. This position is taken as a result of trying to delve into the issue of contingency and causality of being which has been discussed by many philosophers of diverse epochs of philosophy. This work tries to participate in the debate of whether contingent ...

  6. Modeling the 2014 Ebola Virus Epidemic - Agent-Based Simulations, Temporal Analysis and Future Predictions for Liberia and Sierra Leone.

    Science.gov (United States)

    Siettos, Constantinos; Anastassopoulou, Cleo; Russo, Lucia; Grigoras, Christos; Mylonakis, Eleftherios

    2015-03-09

    We developed an agent-based model to investigate the epidemic dynamics of Ebola virus disease (EVD) in Liberia and Sierra Leone from May 27 to December 21, 2014. The dynamics of the agent-based simulator evolve on small-world transmission networks of sizes equal to the population of each country, with adjustable densities to account for the effects of public health intervention policies and individual behavioral responses to the evolving epidemic. Based on time series of the official case counts from the World Health Organization (WHO), we provide estimates for key epidemiological variables by employing the so-called Equation-Free approach. The underlying transmission networks were characterized by rather random structures in the two countries with densities decreasing by ~19% from the early (May 27-early August) to the last period (mid October-December 21). Our estimates for the values of key epidemiological variables, such as the mean time to death, recovery and the case fatality rate, are very close to the ones reported by the WHO Ebola response team during the early period of the epidemic (until September 14) that were calculated based on clinical data. Specifically, regarding the effective reproductive number Re, our analysis suggests that until mid October, Re was above 2.3 in both countries; from mid October to December 21, Re dropped well below unity in Liberia, indicating a saturation of the epidemic, while in Sierra Leone it was around 1.9, indicating an ongoing epidemic. Accordingly, a ten-week projection from December 21 estimated that the epidemic will fade out in Liberia in early March; in contrast, our results flashed a note of caution for Sierra Leone since the cumulative number of cases could reach as high as 18,000, and the number of deaths might exceed 5,000, by early March 2015. However, by processing the reported data of the very last period (December 21, 2014-January 18, 2015), we obtained more optimistic estimates indicative of a remission of

  7. Causality and headache triggers

    Science.gov (United States)

    Turner, Dana P.; Smitherman, Todd A.; Martin, Vincent T.; Penzien, Donald B.; Houle, Timothy T.

    2013-01-01

    Objective The objective of this study was to explore the conditions necessary to assign causal status to headache triggers. Background The term “headache trigger” is commonly used to label any stimulus that is assumed to cause headaches. However, the assumptions required for determining if a given stimulus in fact has a causal-type relationship in eliciting headaches have not been explicated. Methods A synthesis and application of Rubin’s Causal Model is applied to the context of headache causes. From this application the conditions necessary to infer that one event (trigger) causes another (headache) are outlined using basic assumptions and examples from relevant literature. Results Although many conditions must be satisfied for a causal attribution, three basic assumptions are identified for determining causality in headache triggers: 1) constancy of the sufferer; 2) constancy of the trigger effect; and 3) constancy of the trigger presentation. A valid evaluation of a potential trigger’s effect can only be undertaken once these three basic assumptions are satisfied during formal or informal studies of headache triggers. Conclusions Evaluating these assumptions is extremely difficult or infeasible in clinical practice, and satisfying them during natural experimentation is unlikely. Researchers, practitioners, and headache sufferers are encouraged to avoid natural experimentation to determine the causal effects of headache triggers. Instead, formal experimental designs or retrospective diary studies using advanced statistical modeling techniques provide the best approaches to satisfy the required assumptions and inform causal statements about headache triggers. PMID:23534872

  8. Causality re-established.

    Science.gov (United States)

    D'Ariano, Giacomo Mauro

    2018-07-13

    Causality has never gained the status of a 'law' or 'principle' in physics. Some recent literature has even popularized the false idea that causality is a notion that should be banned from theory. Such misconception relies on an alleged universality of the reversibility of the laws of physics, based either on the determinism of classical theory, or on the multiverse interpretation of quantum theory, in both cases motivated by mere interpretational requirements for realism of the theory. Here, I will show that a properly defined unambiguous notion of causality is a theorem of quantum theory, which is also a falsifiable proposition of the theory. Such a notion of causality appeared in the literature within the framework of operational probabilistic theories. It is a genuinely theoretical notion, corresponding to establishing a definite partial order among events, in the same way as we do by using the future causal cone on Minkowski space. The notion of causality is logically completely independent of the misidentified concept of 'determinism', and, being a consequence of quantum theory, is ubiquitous in physics. In addition, as classical theory can be regarded as a restriction of quantum theory, causality holds also in the classical case, although the determinism of the theory trivializes it. I then conclude by arguing that causality naturally establishes an arrow of time. This implies that the scenario of the 'block Universe' and the connected 'past hypothesis' are incompatible with causality, and thus with quantum theory: they are both doomed to remain mere interpretations and, as such, are not falsifiable, similar to the hypothesis of 'super-determinism'.This article is part of a discussion meeting issue 'Foundations of quantum mechanics and their impact on contemporary society'. © 2018 The Author(s).

  9. Identification and application of biocontrol agents against Cotton leaf curl virus disease in Gossypium hirsutum under greenhouse conditions

    Directory of Open Access Journals (Sweden)

    Memoona Ramzan

    2016-05-01

    Full Text Available Biological control is a novel approach in crop protection. Bacteria, such as Bacillus spp. and Pseudomonas spp., are reported for this purpose and some of their products are already commercially available. In this study, the rhizosphere and phyllosphere of healthy cotton plants were used as a source of bacterial isolates with properties of potential biocontrol agents. The isolates were screened for phosphate solubilization activity, indole acetic acid (IAA production and antifungal activity. Two isolates, S1HL3 and S1HL4, showed phosphate solubilization and IAA production simultaneously, while another two, JS2HR4 and JS3HR2, demonstrated potential to inhibit fungal pathogens. These bacteria were identified as Pseudomonas aeruginosa (S1HL3, Burkholderia sp. (S1HL4 and Bacillus sp. (JS2HR4 and JS3HR2 based on biochemical and molecular characteristics. The isolates were tested against Cotton leaf curl virus (CLCuV in greenhouse conditions, both as individual bacterial isolates and consortia. Treated plants were healthy as compared to control plants, where up to 74% of the plants were symptomatic for CLCuV infection. Maximum inhibition of CLCuV was observed in the plants treated with a mixture of bacterial isolates: the viral load in the treated plants was only 0.4% vs. up to 74% in controls. This treatment consortium included P. aeruginosa S1HL3, Burkholderia sp. S1HL4 and Bacillus spp. isolates, JS2HR4 and JS3HR2. The principal-component biplot showed a highly significant correlation between the viral load percentage and the disease incidence.

  10. Causal inference regarding infectious aetiology of chronic conditions: a systematic review.

    Directory of Open Access Journals (Sweden)

    Sofia Orrskog

    Full Text Available BACKGROUND: The global burden of disease has shifted from communicable diseases in children to chronic diseases in adults. This epidemiologic shift varies greatly by region, but in Europe, chronic conditions account for 86% of all deaths, 77% of the disease burden, and up to 80% of health care expenditures. A number of risk factors have been implicated in chronic diseases, such as exposure to infectious agents. A number of associations have been well established while others remain uncertain. METHODS AND FINDINGS: We assessed the body of evidence regarding the infectious aetiology of chronic diseases in the peer-reviewed literature over the last decade. Causality was assessed with three different criteria: First, the total number of associations documented in the literature between each infectious agent and chronic condition; second, the epidemiologic study design (quality of the study; third, evidence for the number of Hill's criteria and Koch's postulates that linked the pathogen with the chronic condition. We identified 3136 publications, of which 148 were included in the analysis. There were a total of 75 different infectious agents and 122 chronic conditions. The evidence was strong for five pathogens, based on study type, strength and number of associations; they accounted for 60% of the associations documented in the literature. They were human immunodeficiency virus, hepatitis C virus, Helicobacter pylori, hepatitis B virus, and Chlamydia pneumoniae and were collectively implicated in the aetiology of 37 different chronic conditions. Other pathogens examined were only associated with very few chronic conditions (≤ 3 and when applying the three different criteria of evidence the strength of the causality was weak. CONCLUSIONS: Prevention and treatment of these five pathogens lend themselves as effective public health intervention entry points. By concentrating research efforts on these promising areas, the human, economic, and societal

  11. Viruses as the causative agent related to 'dampness' and the missing link between allergen exposure and onset of allergic disease

    DEFF Research Database (Denmark)

    Hersoug, Lars-Georg

    2005-01-01

    concentration and symptoms indicate a missing link between allergen exposure and onset of asthma. Respiratory viruses have been identified in up to 85% cases of asthma or exacerbations of asthma. The missing link between respiratory diseases and humid indoor climates could therefore be attributed to viruses....... The infectious effectiveness of respiratory viruses depends strongly on the environment where the viruses are spread. For respiratory viruses, survival and infectivity are dependent on temperature and relative humidity. A direct link between virus-induced inflammation and the asthmatogenic process has been...... subjects. Therefore, a humid indoor climate could also represent a higher risk for persons already sensitized to one or more allergens. PRACTICAL IMPLICATIONS: In epidemiological studies where the relationship between moisture in the indoor climate, respiratory symptoms and exposure to allergens...

  12. Marketed nonsteroidal anti-inflammatory agents, antihypertensives, and human immunodeficiency virus protease inhibitors: as-yet-unused weapons of the oncologists’ arsenal

    Directory of Open Access Journals (Sweden)

    Papanagnou P

    2015-05-01

    Full Text Available Panagiota Papanagnou,1 Panagiotis Baltopoulos,2 Maria Tsironi1 1Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, 2Department of Sports Medicine and Biology of Physical Activity, Faculty of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece Abstract: Experimental data indicate that several pharmacological agents that have long been used for the management of various diseases unrelated to cancer exhibit profound in vitro and in vivo anticancer activity. This is of major clinical importance, since it would possibly aid in reassessing the therapeutic use of currently used agents for which clinicians already have experience. Further, this would obviate the time-consuming process required for the development and the approval of novel antineoplastic drugs. Herein, both pre-clinical and clinical data concerning the antineoplastic function of distinct commercially available pharmacological agents that are not currently used in the field of oncology, ie, nonsteroidal anti-inflammatory drugs, antihypertensive agents, and anti-human immunodeficiency virus agents inhibiting viral protease, are reviewed. The aim is to provide integrated information regarding not only the molecular basis of the antitumor function of these agents but also the applicability of the reevaluation of their therapeutic range in the clinical setting. Keywords: repositioning, tumorigenesis, pleiotropy, exploitation

  13. Tachyons and causal paradoxes

    International Nuclear Information System (INIS)

    Maund, J.B.

    1979-01-01

    Although the existence of tachyons is not ruled out by special relativity, it appears that causal paradoxes will arise if there are tachyons. The usual solutions to these paradoxes employ some form of the reinterpretation principle. In this paper it is argued first that, the principle is incoherent, second, that even if it is not, some causal paradoxes remain, and third, the most plausible ''solution,'' which appeals to boundary conditions of the universe, will conflict with special relativity

  14. Dynamics and causality constraints

    International Nuclear Information System (INIS)

    Sousa, Manoelito M. de

    2001-04-01

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

  15. Causality discovery technology

    Science.gov (United States)

    Chen, M.; Ertl, T.; Jirotka, M.; Trefethen, A.; Schmidt, A.; Coecke, B.; Bañares-Alcántara, R.

    2012-11-01

    Causality is the fabric of our dynamic world. We all make frequent attempts to reason causation relationships of everyday events (e.g., what was the cause of my headache, or what has upset Alice?). We attempt to manage causality all the time through planning and scheduling. The greatest scientific discoveries are usually about causality (e.g., Newton found the cause for an apple to fall, and Darwin discovered natural selection). Meanwhile, we continue to seek a comprehensive understanding about the causes of numerous complex phenomena, such as social divisions, economic crisis, global warming, home-grown terrorism, etc. Humans analyse and reason causality based on observation, experimentation and acquired a priori knowledge. Today's technologies enable us to make observations and carry out experiments in an unprecedented scale that has created data mountains everywhere. Whereas there are exciting opportunities to discover new causation relationships, there are also unparalleled challenges to benefit from such data mountains. In this article, we present a case for developing a new piece of ICT, called Causality Discovery Technology. We reason about the necessity, feasibility and potential impact of such a technology.

  16. A quantum causal discovery algorithm

    Science.gov (United States)

    Giarmatzi, Christina; Costa, Fabio

    2018-03-01

    Finding a causal model for a set of classical variables is now a well-established task—but what about the quantum equivalent? Even the notion of a quantum causal model is controversial. Here, we present a causal discovery algorithm for quantum systems. The input to the algorithm is a process matrix describing correlations between quantum events. Its output consists of different levels of information about the underlying causal model. Our algorithm determines whether the process is causally ordered by grouping the events into causally ordered non-signaling sets. It detects if all relevant common causes are included in the process, which we label Markovian, or alternatively if some causal relations are mediated through some external memory. For a Markovian process, it outputs a causal model, namely the causal relations and the corresponding mechanisms, represented as quantum states and channels. Our algorithm opens the route to more general quantum causal discovery methods.

  17. Causal symmetric spaces

    CERN Document Server

    Olafsson, Gestur; Helgason, Sigurdur

    1996-01-01

    This book is intended to introduce researchers and graduate students to the concepts of causal symmetric spaces. To date, results of recent studies considered standard by specialists have not been widely published. This book seeks to bring this information to students and researchers in geometry and analysis on causal symmetric spaces.Includes the newest results in harmonic analysis including Spherical functions on ordered symmetric space and the holmorphic discrete series and Hardy spaces on compactly casual symmetric spacesDeals with the infinitesimal situation, coverings of symmetric spaces, classification of causal symmetric pairs and invariant cone fieldsPresents basic geometric properties of semi-simple symmetric spacesIncludes appendices on Lie algebras and Lie groups, Bounded symmetric domains (Cayley transforms), Antiholomorphic Involutions on Bounded Domains and Para-Hermitian Symmetric Spaces

  18. Causal inference in econometrics

    CERN Document Server

    Kreinovich, Vladik; Sriboonchitta, Songsak

    2016-01-01

    This book is devoted to the analysis of causal inference which is one of the most difficult tasks in data analysis: when two phenomena are observed to be related, it is often difficult to decide whether one of them causally influences the other one, or whether these two phenomena have a common cause. This analysis is the main focus of this volume. To get a good understanding of the causal inference, it is important to have models of economic phenomena which are as accurate as possible. Because of this need, this volume also contains papers that use non-traditional economic models, such as fuzzy models and models obtained by using neural networks and data mining techniques. It also contains papers that apply different econometric models to analyze real-life economic dependencies.

  19. The causal structure of utility conditionals.

    Science.gov (United States)

    Bonnefon, Jean-François; Sloman, Steven A

    2013-01-01

    The psychology of reasoning is increasingly considering agents' values and preferences, achieving greater integration with judgment and decision making, social cognition, and moral reasoning. Some of this research investigates utility conditionals, ''if p then q'' statements where the realization of p or q or both is valued by some agents. Various approaches to utility conditionals share the assumption that reasoners make inferences from utility conditionals based on the comparison between the utility of p and the expected utility of q. This article introduces a new parameter in this analysis, the underlying causal structure of the conditional. Four experiments showed that causal structure moderated utility-informed conditional reasoning. These inferences were strongly invited when the underlying structure of the conditional was causal, and significantly less so when the underlying structure of the conditional was diagnostic. This asymmetry was only observed for conditionals in which the utility of q was clear, and disappeared when the utility of q was unclear. Thus, an adequate account of utility-informed inferences conditional reasoning requires three components: utility, probability, and causal structure. Copyright © 2012 Cognitive Science Society, Inc.

  20. Estimation of the age-specific per-contact probability of Ebola virus transmission in Liberia using agent-based simulations

    Science.gov (United States)

    Siettos, Constantinos I.; Anastassopoulou, Cleo; Russo, Lucia; Grigoras, Christos; Mylonakis, Eleftherios

    2016-06-01

    Based on multiscale agent-based computations we estimated the per-contact probability of transmission by age of the Ebola virus disease (EVD) that swept through Liberia from May 2014 to March 2015. For the approximation of the epidemic dynamics we have developed a detailed agent-based model with small-world interactions between individuals categorized by age. For the estimation of the structure of the evolving contact network as well as the per-contact transmission probabilities by age group we exploited the so called Equation-Free framework. Model parameters were fitted to official case counts reported by the World Health Organization (WHO) as well as to recently published data of key epidemiological variables, such as the mean time to death, recovery and the case fatality rate.

  1. Descripción del ingreso del virus de la rabia desde la periferia hasta la médula espinal en un modelo de ratón adulto

    Directory of Open Access Journals (Sweden)

    Marlén Martínez Gutiérrez

    2005-03-01

    Full Text Available El virus de rabia (VR es el agente causal de la enfermedad conocida como hidrofobia.  Una vez inoculado en la periferia, el VR es capturado y transportado por las terminaciones sensoriales y/o motoras presentes en el sitio de la inoculación, hasta el sistema nervioso.

  2. Development and validation of a real-time two-step RT-qPCR TaqMan(®) assay for quantitation of Sacbrood virus (SBV) and its application to a field survey of symptomatic honey bee colonies

    DEFF Research Database (Denmark)

    Blanchard, Philippe; Guillot, Sylvain; Antùnez, Karina

    2014-01-01

    Sacbrood virus (SBV) is the causal agent of a disease of honey bee larvae, resulting in failure to pupate and causing death. The typical clinical symptom of SBV is an accumulation of SBV-rich fluid in swollen sub-cuticular pouches, forming the characteristic fluid-filled sac that gives its name t...

  3. Maximally causal quantum mechanics

    International Nuclear Information System (INIS)

    Roy, S.M.

    1998-01-01

    We present a new causal quantum mechanics in one and two dimensions developed recently at TIFR by this author and V. Singh. In this theory both position and momentum for a system point have Hamiltonian evolution in such a way that the ensemble of system points leads to position and momentum probability densities agreeing exactly with ordinary quantum mechanics. (author)

  4. Causality in demand

    DEFF Research Database (Denmark)

    Nielsen, Max; Jensen, Frank; Setälä, Jari

    2011-01-01

    to fish demand. On the German market for farmed trout and substitutes, it is found that supply sources, i.e. aquaculture and fishery, are not the only determinant of causality. Storing, tightness of management and aggregation level of integrated markets might also be important. The methodological...

  5. Causality and Free Will

    Czech Academy of Sciences Publication Activity Database

    Hvorecký, Juraj

    2012-01-01

    Roč. 19, Supp.2 (2012), s. 64-69 ISSN 1335-0668 R&D Projects: GA ČR(CZ) GAP401/12/0833 Institutional support: RVO:67985955 Keywords : conciousness * free will * determinism * causality Subject RIV: AA - Philosophy ; Religion

  6. Explaining through causal mechanisms

    NARCIS (Netherlands)

    Biesbroek, Robbert; Dupuis, Johann; Wellstead, Adam

    2017-01-01

    This paper synthesizes and builds on recent critiques of the resilience literature; namely that the field has largely been unsuccessful in capturing the complexity of governance processes, in particular cause–effects relationships. We demonstrate that absence of a causal model is reflected in the

  7. Optimal causal inference: estimating stored information and approximating causal architecture.

    Science.gov (United States)

    Still, Susanne; Crutchfield, James P; Ellison, Christopher J

    2010-09-01

    We introduce an approach to inferring the causal architecture of stochastic dynamical systems that extends rate-distortion theory to use causal shielding--a natural principle of learning. We study two distinct cases of causal inference: optimal causal filtering and optimal causal estimation. Filtering corresponds to the ideal case in which the probability distribution of measurement sequences is known, giving a principled method to approximate a system's causal structure at a desired level of representation. We show that in the limit in which a model-complexity constraint is relaxed, filtering finds the exact causal architecture of a stochastic dynamical system, known as the causal-state partition. From this, one can estimate the amount of historical information the process stores. More generally, causal filtering finds a graded model-complexity hierarchy of approximations to the causal architecture. Abrupt changes in the hierarchy, as a function of approximation, capture distinct scales of structural organization. For nonideal cases with finite data, we show how the correct number of the underlying causal states can be found by optimal causal estimation. A previously derived model-complexity control term allows us to correct for the effect of statistical fluctuations in probability estimates and thereby avoid overfitting.

  8. Molecular characterization of Prunus necrotic ringspot virus isolated from rose in Brazil.

    OpenAIRE

    FAJARDO, T. V. M.; NASCIMENTO, M. B.; EIRAS, M.; NICKEL, O.; PIO-RIBEIRO, G.

    2016-01-01

    ABSTRACT: There is no molecular characterization of Brazilian isolates of Prunus necrotic ringspot virus (PNRSV), except for those infecting peach. In this research, the causal agent of rose mosaic was determined and the movement (MP) and coat (CP) protein genes of a PNRSV isolate from rose were molecularly characterized for the first time in Brazil. The nucleotide and deduced amino acid sequences of MP and CP complete genes were aligned and compared with other isolates. Molecular analysis of...

  9. Operator ordering and causality

    OpenAIRE

    Plimak, L. I.; Stenholm, S. T.

    2011-01-01

    It is shown that causality violations [M. de Haan, Physica 132A, 375, 397 (1985)], emerging when the conventional definition of the time-normal operator ordering [P.L.Kelley and W.H.Kleiner, Phys.Rev. 136, A316 (1964)] is taken outside the rotating wave approximation, disappear when the amended definition [L.P. and S.S., Annals of Physics, 323, 1989 (2008)] of this ordering is used.

  10. Space, time and causality

    International Nuclear Information System (INIS)

    Lucas, J.R.

    1984-01-01

    Originating from lectures given to first year undergraduates reading physics and philosophy or mathematics and philosophy, formal logic is applied to issues and the elucidation of problems in space, time and causality. No special knowledge of relativity theory or quantum mechanics is needed. The text is interspersed with exercises and each chapter is preceded by a suggested 'preliminary reading' and followed by 'further reading' references. (U.K.)

  11. The challenge of treating hepatitis C virus-associated cryoglobulinemic vasculitis in the era of anti-CD20 monoclonal antibodies and direct antiviral agents.

    Science.gov (United States)

    Roccatello, Dario; Sciascia, Savino; Rossi, Daniela; Solfietti, Laura; Fenoglio, Roberta; Menegatti, Elisa; Baldovino, Simone

    2017-06-20

    Mixed cryoglobulinemia syndrome (MC) is a systemic vasculitis involving kidneys, joints, skin, and peripheral nerves. While many autoimmune, lymphoproliferative, and neoplastic disorders have been associated with this disorder, hepatitis C virus (HCV) is known to be the etiologic agent in the majority of patients. Therefore, clinical research has focused on anti-viral drugs and, more recently, on the new, highly potent Direct-acting Antiviral Agents (DAAs). These drugs assure sustained virologic response (SVR) rates >90%. Nevertheless, data on their efficacy in patients with HCV-associated cryoglobulinemic vasculitis are disappointing, possibly due to the inability of the drugs to suppress the immune-mediated process once it has been triggered.Despite the potential risk of exacerbation of the infection, immunosuppression has traditionally been regarded as the first-line intervention in cryoglobulinemic vasculitis, especially if renal involvement is severe. Biologic agents have raised hopes for more manageable therapeutic approaches, and Rituximab (RTX), an anti CD20 monoclonal antibody, is the most widely used biologic drug. It has proved to be safer than conventional immunosuppressants, thus substantially changing the natural history of HCV-associated cryoglobulinemic vasculitis by providing long-term remission, especially with intensive regimens.The present review focuses on the new therapeutic opportunities offered by the combination of biological drugs, mainly Rituximab, with DAAs.

  12. Identification of Antiviral Agents Targeting Hepatitis B Virus Promoter from Extracts of Indonesian Marine Organisms by a Novel Cell-Based Screening Assay

    Science.gov (United States)

    Yamashita, Atsuya; Fujimoto, Yuusuke; Tamaki, Mayumi; Setiawan, Andi; Tanaka, Tomohisa; Okuyama-Dobashi, Kaori; Kasai, Hirotake; Watashi, Koichi; Wakita, Takaji; Toyama, Masaaki; Baba, Masanori; de Voogd, Nicole J.; Maekawa, Shinya; Enomoto, Nobuyuki; Tanaka, Junichi; Moriishi, Kohji

    2015-01-01

    The current treatments of chronic hepatitis B (CHB) face a limited choice of vaccine, antibody and antiviral agents. The development of additional antiviral agents is still needed for improvement of CHB therapy. In this study, we established a screening system in order to identify compounds inhibiting the core promoter activity of hepatitis B virus (HBV). We prepared 80 extracts of marine organisms from the coral reefs of Indonesia and screened them by using this system. Eventually, two extracts showed high inhibitory activity (>95%) and low cytotoxicity (66% to 77%). Solvent fractionation, column chromatography and NMR analysis revealed that 3,5-dibromo-2-(2,4-dibromophenoxy)-phenol (compound 1) and 3,4,5-tribromo-2-(2,4-dibromophenoxy)-phenol (compound 2), which are classified as polybrominated diphenyl ethers (PBDEs), were identified as anti-HBV agents in the extracts. Compounds 1 and 2 inhibited HBV core promoter activity as well as HBV production from HepG2.2.15.7 cells in a dose-dependent manner. The EC50 values of compounds 1 and 2 were 0.23 and 0.80 µM, respectively, while selectivity indexes of compound 1 and 2 were 18.2 and 12.8, respectively. These results suggest that our cell-based HBV core promoter assay system is useful to determine anti-HBV compounds, and that two PBDE compounds are expected to be candidates of lead compounds for the development of anti-HBV drugs. PMID:26561821

  13. Antisense Treatments for Biothreat Agents

    National Research Council Canada - National Science Library

    Warfield, Kelly L; Panchal, Rekha G; Aman, M J; Bavari, Sina

    2006-01-01

    ... a variety of pathogens in cell culture studies and nonhuman primate models of infection. For these reasons, antisense technologies are being pursued as treatments against biothreat agents such as Ebola virus, dengue virus and Bacillus anthracis...

  14. Hepatitis C virus eradication by direct antiviral agents improves glucose tolerance and reduces post-load insulin resistance in nondiabetic patients with genotype 1.

    Science.gov (United States)

    Salomone, Federico; Catania, Maurizio; Montineri, Arturo; Bertino, Gaetano; Godos, Justyna; Rizzo, Leonardo; Magrì, Giovanni; Li Volti, Giovanni

    2017-12-19

    Genotype 1 chronic hepatitis C is associated with an impairment of glucose homoeostasis, especially in the advanced stages of the disease. Glucose tolerance is an independent predictor of liver-related mortality in patients with cirrhosis because of chronic hepatitis C. However, no study has demonstrated so far weather hepatitis C virus clearance affects glucose tolerance. To this aim, we performed a prospective study assessing the effects of direct antiviral agents treatment in nondiabetic cirrhotic patients with genotypes 1a/1b and impaired glucose tolerance based on a 75-g oral glucose tolerance test. Impaired glucose tolerance was diagnosed by a 2-hour plasma glucose between 140 and 199 mg/dL. Insulin resistance was estimated by the oral glucose insulin sensitivity index, an oral glucose tolerance test-derived measure. After meeting the inclusion criteria, the study population included 32 outpatients (26/6 genotypes 1b/1a; age 62 ± 7.4 years; 18 males) with compensated Child-A cirrhosis. All patients achieved a sustained virological response following direct antiviral agents treatment. After viral eradication, we did not observe change in fasting plasma glucose (103.5 ± 7.1 vs 102.8 ± 7.2 mg/dL, P = .15) but 2-hour plasma glucose was reduced (165.2 ± 22.7 vs 138.5 ± 21.3 mg/dL, P Hepatitis C virus eradication led also to a significant reduction in HbA1c (6.1 ± 0.2% vs 5.7 ± 0.3%, P resistance as assessed by the oral glucose insulin sensitivity index (6.92 ± 1.56 vs 9.52 ± 1.39 mg/kg/min, P  .5). Our results indicate that hepatitis C virus eradication may early improve glucose tolerance in patients with hepatitis C virus-related cirrhosis. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Direct-acting antiviral agent efficacy and safety in renal transplant recipients with chronic hepatitis C virus infection

    OpenAIRE

    Chen, Keliang; Lu, Pei; Song, Rijin; Zhang, Jiexiu; Tao, Rongzhen; Wang, Zijie; Zhang, Wei; Gu, Min

    2017-01-01

    Abstract Background: The efficacy and safety of direct-acting antivirals (DAAs) for treating hepatitis C virus (HCV)-infected renal transplant recipients (RTRs) has not been determined. Methods: We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials and assessed the quality of eligible studies using the Joanna Briggs Institute scale. DAA efficacy and safety were assessed using standard mean difference (SMD) with 95% confidence intervals (95%CIs). Results: Six studi...

  16. Comparative study of inactivation of herpes simplex virus types 1 and 2 by commonly used antiseptic agents

    International Nuclear Information System (INIS)

    Croughan, W.S.; Behbehani, A.M.

    1988-01-01

    A comparative study of the different reactions of herpes simplex virus types 1 and 2 to Lysol, Listerine, bleach, rubbing alcohol, Alcide disinfectant (Alcide Corp., Westport, Conn.), and various pHs, temperatures, and UV light exposures was performed. Both types of stock virus (titers of approximately 10(6) and 10(5.5) for types 1 and 2, respectively) were inactivated by 0.5% Lysol in 5 min; by Listerine (1:1 mixtures) in 5 min; by 2000 ppm (2000 microliters/liter) of bleach in 10 min; by rubbing alcohol (1:1 mixtures) at zero time; by Alcide disinfectant (0.2 ml of virus plus 2.0 ml of Alcide) at zero time; by pHs 3, 5, and 11 in 10 min; and by a temperature of 56 degrees C in 30 min. A germicidal lamp at a distance of 48 cm failed to completely inactivate the two types in 15 min. Type 1 showed slightly more resistance to Listerine and bleach and significantly more resistance to heat; moreover, pH 9 did not affect the infectivity of either type after 10 min

  17. Detection and quantification of potato mop-top virus (pmtv) in colombia using qrt-pcr

    OpenAIRE

    García Bastidas, Nevar Alirio; Gutiérrez Sánchez, Pablo Andrés; Marín Montoya, Mauricio Alejandro

    2014-01-01

    El Potato mop-top virus (PMTV) es uno de los virus re-emergentes en cultivos de papa en Colombia. Es transmitido por Spongospora subterranea, el agente causal de la sarna polvosa. La detección del PMTV presenta dificultades debido a su distribución irregular en las plantas, bajo título y movimiento sistémico como ARN desnudo. Con el fin de ampliar el rango de herramientas disponibles para detectar el PMTV en los programas de certificación de tubérculo-semilla, en este estudio se evaluó la pru...

  18. Causal events enter awareness faster than non-causal events

    Directory of Open Access Journals (Sweden)

    Pieter Moors

    2017-01-01

    Full Text Available Philosophers have long argued that causality cannot be directly observed but requires a conscious inference (Hume, 1967. Albert Michotte however developed numerous visual phenomena in which people seemed to perceive causality akin to primary visual properties like colour or motion (Michotte, 1946. Michotte claimed that the perception of causality did not require a conscious, deliberate inference but, working over 70 years ago, he did not have access to the experimental methods to test this claim. Here we employ Continuous Flash Suppression (CFS—an interocular suppression technique to render stimuli invisible (Tsuchiya & Koch, 2005—to test whether causal events enter awareness faster than non-causal events. We presented observers with ‘causal’ and ‘non-causal’ events, and found consistent evidence that participants become aware of causal events more rapidly than non-causal events. Our results suggest that, whilst causality must be inferred from sensory evidence, this inference might be computed at low levels of perceptual processing, and does not depend on a deliberative conscious evaluation of the stimulus. This work therefore supports Michotte’s contention that, like colour or motion, causality is an immediate property of our perception of the world.

  19. Deep Sequencing Data and Infectivity Assays Indicate that Chickpea Chlorotic Dwarf Virus is the Etiological Agent of the “Hard Fruit Syndrome” of Watermelon

    Directory of Open Access Journals (Sweden)

    Takoua Zaagueri

    2017-10-01

    Full Text Available Chickpea chlorotic dwarf virus (CpCDV, a polyphagous mastrevirus, family Geminiviridae, has been recently linked to the onset of the “hard fruit syndrome” of watermelon, first described in Tunisia, that makes fruits unmarketable due to the presence of white hard portions in the flesh, chlorotic mottling on the rind, and an unpleasant taste. To investigate the etiological agent of this disease, total RNA extracted from symptomatic watermelon fruits was subjected to small RNA sequencing through next generation sequencing (NGS techniques. Data obtained showed the presence of CpCDV and two other viral species. However, following validation through polymerase chain reaction (PCR, CpCDV was the only viral species consistently detected in all samples. Watermelon seedlings were then challenged by an agroinfectious CpCDV clone; several plants proved to be CpCDV-infected, and were able to produce fruits. CpCDV infected and replicated in watermelon fruits and leaves, leading to abnormality in fruits and in seed production, similar to those described in field. These results indicate that CpCDV is the etiological agent of the “hard fruit syndrome” of watermelon.

  20. 2015 Philip S. Portoghese Medicinal Chemistry Lectureship. Curing Hepatitis C Virus Infection with Direct-Acting Antiviral Agents: The Arc of a Medicinal Chemistry Triumph.

    Science.gov (United States)

    Meanwell, Nicholas A

    2016-08-25

    The development of direct-acting antiviral agents that can cure a chronic hepatitis C virus (HCV) infection after 8-12 weeks of daily, well-tolerated therapy has revolutionized the treatment of this insidious disease. In this article, three of Bristol-Myers Squibb's HCV programs are summarized, each of which produced a clinical candidate: the NS3 protease inhibitor asunaprevir (64), marketed as Sunvepra, the NS5A replication complex inhibitor daclatasvir (117), marketed as Daklinza, and the allosteric NS5B polymerase inhibitor beclabuvir (142), which is in late stage clinical studies. A clinical study with 64 and 117 established for the first time that a chronic HCV infection could be cured by treatment with direct-acting antiviral agents alone in the absence of interferon. The development of small molecule HCV therapeutics, designed by medicinal chemists, has been hailed as "the arc of a medical triumph" but may equally well be described as "the arc of a medicinal chemistry triumph".

  1. Antimicrobial Peptides Derived from Fusion Peptides of Influenza A Viruses, a Promising Approach to Designing Potent Antimicrobial Agents.

    Science.gov (United States)

    Wang, Jingyu; Zhong, Wenjing; Lin, Dongguo; Xia, Fan; Wu, Wenjiao; Zhang, Heyuan; Lv, Lin; Liu, Shuwen; He, Jian

    2015-10-01

    The emergence and dissemination of antibiotic-resistant bacterial pathogens have spurred the urgent need to develop novel antimicrobial agents with different mode of action. In this respect, we turned several fusogenic peptides (FPs) derived from the hemagglutinin glycoproteins (HAs) of IAV into potent antibacterials by replacing the negatively or neutrally charged residues of FPs with positively charged lysines. Their antibacterial activities were evaluated by testing the MICs against a panel of bacterial strains including S. aureus, S. mutans, P. aeruginosa, and E. coli. The results showed that peptides HA-FP-1, HA-FP-2-1, and HA-FP-3-1 were effective against both Gram-positive and Gram-negative bacteria with MICs ranging from 1.9 to 16.0 μm, while the toxicities toward mammalian cells were low. In addition, the mode of action and the secondary structure of these peptides were also discussed. These data not only provide several potent peptides displaying promising potential in development as broad antimicrobial agents, but also present a useful strategy in designing new antimicrobial agents. © 2015 John Wiley & Sons A/S.

  2. Causal inference based on counterfactuals

    Directory of Open Access Journals (Sweden)

    Höfler M

    2005-09-01

    Full Text Available Abstract Background The counterfactual or potential outcome model has become increasingly standard for causal inference in epidemiological and medical studies. Discussion This paper provides an overview on the counterfactual and related approaches. A variety of conceptual as well as practical issues when estimating causal effects are reviewed. These include causal interactions, imperfect experiments, adjustment for confounding, time-varying exposures, competing risks and the probability of causation. It is argued that the counterfactual model of causal effects captures the main aspects of causality in health sciences and relates to many statistical procedures. Summary Counterfactuals are the basis of causal inference in medicine and epidemiology. Nevertheless, the estimation of counterfactual differences pose several difficulties, primarily in observational studies. These problems, however, reflect fundamental barriers only when learning from observations, and this does not invalidate the counterfactual concept.

  3. Causal inference in public health.

    Science.gov (United States)

    Glass, Thomas A; Goodman, Steven N; Hernán, Miguel A; Samet, Jonathan M

    2013-01-01

    Causal inference has a central role in public health; the determination that an association is causal indicates the possibility for intervention. We review and comment on the long-used guidelines for interpreting evidence as supporting a causal association and contrast them with the potential outcomes framework that encourages thinking in terms of causes that are interventions. We argue that in public health this framework is more suitable, providing an estimate of an action's consequences rather than the less precise notion of a risk factor's causal effect. A variety of modern statistical methods adopt this approach. When an intervention cannot be specified, causal relations can still exist, but how to intervene to change the outcome will be unclear. In application, the often-complex structure of causal processes needs to be acknowledged and appropriate data collected to study them. These newer approaches need to be brought to bear on the increasingly complex public health challenges of our globalized world.

  4. Selective enhancement of radiation response of herpes simplex virus thymidine kinase transduced 9L gliosarcoma cells in vitro and in vivo by antiviral agents

    International Nuclear Information System (INIS)

    Kim, Jae Ho; Kim, Sang Hie; Kolozsvary, A.

    1995-01-01

    The purpose of this investigation was to demonstrate in a well-characterized tumor model that the radiosensitivity of tumor cells transduced with a herpes simplex virus thymidine kinase gene (HS-tk) would be selectively enhanced by antiviral agents. Rat 9L gliosarcoma cells transduced with a retroviral vector containing an HS-tk gene, 9L-tk cells were exposed to various doses or irradiation under either in vitro or in vivo conditions. The radiation sensitizing potential of two antiviral drugs, bromovinyl deoxyuridine (BVdU) and dihydroxymethyl ethyl methyl guanine (acyclovir), was evaluated in vitro. The radiosensitizing ability of BVdU was also evaluated with a 9L-tk tumor growing in the rat brain. Tumors growing in the right hemisphere of rat brains were irradiated stereotactically with single-dose irradiation. The radiation response of 9L-tk cells was selectively enhanced by antiviral agents relative to nontransduced cells. In the cell culture, when a 24-h drug exposure (20 μg/ml) preceded radiation, the sensitizer enhancement ratio (SER) for BVdU and acyclovir was 1.4 ± 0.1 and 1.3 ± 0.1, respectively. Exposure of cells to 10 μg/ml acyclovir for two 24-h periods both pre- and postirradiation resulted in a SER of 1.6 ± 0.1. In vivo, a significant increase in median survival time of rats with 9L-tk tumors was found when BVdU was administered prior to single-dose irradiation relative to the survival time of similar rats receiving radiation alone. An antiviral agent can enhance cell killing by radiation with selective action in cells transduced with the herpes simplex virus thymidine kinase gene. The results suggest that the three-pronged therapy of HS-tk gene transduction, systemically administered antiviral drug, and stereotactically targeted radiation therapy will improve the effectiveness of radiation therapy for the treatment of radioresistant tumors. 25 refs., 6 figs

  5. Selective enhancement of radiation response of herpes simplex virus thymidine kinase transduced 9L gliosarcoma cells in vitro and in vivo by antiviral agents

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Ho; Kim, Sang Hie; Kolozsvary, A. [Henry Ford Hospital, Detroit, MI (United States)] [and others

    1995-11-01

    The purpose of this investigation was to demonstrate in a well-characterized tumor model that the radiosensitivity of tumor cells transduced with a herpes simplex virus thymidine kinase gene (HS-tk) would be selectively enhanced by antiviral agents. Rat 9L gliosarcoma cells transduced with a retroviral vector containing an HS-tk gene, 9L-tk cells were exposed to various doses or irradiation under either in vitro or in vivo conditions. The radiation sensitizing potential of two antiviral drugs, bromovinyl deoxyuridine (BVdU) and dihydroxymethyl ethyl methyl guanine (acyclovir), was evaluated in vitro. The radiosensitizing ability of BVdU was also evaluated with a 9L-tk tumor growing in the rat brain. Tumors growing in the right hemisphere of rat brains were irradiated stereotactically with single-dose irradiation. The radiation response of 9L-tk cells was selectively enhanced by antiviral agents relative to nontransduced cells. In the cell culture, when a 24-h drug exposure (20 {mu}g/ml) preceded radiation, the sensitizer enhancement ratio (SER) for BVdU and acyclovir was 1.4 {plus_minus} 0.1 and 1.3 {plus_minus} 0.1, respectively. Exposure of cells to 10 {mu}g/ml acyclovir for two 24-h periods both pre- and postirradiation resulted in a SER of 1.6 {plus_minus} 0.1. In vivo, a significant increase in median survival time of rats with 9L-tk tumors was found when BVdU was administered prior to single-dose irradiation relative to the survival time of similar rats receiving radiation alone. An antiviral agent can enhance cell killing by radiation with selective action in cells transduced with the herpes simplex virus thymidine kinase gene. The results suggest that the three-pronged therapy of HS-tk gene transduction, systemically administered antiviral drug, and stereotactically targeted radiation therapy will improve the effectiveness of radiation therapy for the treatment of radioresistant tumors. 25 refs., 6 figs.

  6. Selective enhancement of radiation response of herpes simplex virus thymidine kinase transduced 9L gliosarcoma cells in vitro and in vivo by antiviral agents

    International Nuclear Information System (INIS)

    Jae, Ho Kim; Sang, Hie Kim; Kolozsvary, Andrew; Brown, Stephen L.; Ok, Bae Kim; Freytag, Svend O.

    1995-01-01

    Purpose: To demonstrate in a well-characterized tumor model that the radiosensitivity of tumor cells transduced with a herpes simplex virus thymidine kinase gene (HS-tk) would be selectively enhanced by antiviral agents. Methods and Materials: Rat 9L gliosarcoma cells transduced with a retroviral vector containing an HS-tk gene, 9L-tk cells were exposed to various doses of irradiation under either in vitro or in vivo conditions. The radiation sensitizing potential of two antiviral drugs, bromovinyl deoxyuridine (BVdU) and dihydroxymethyl ethyl methyl guanine (acyclovir), was evaluated in vitro. The radiosensitizing ability of BVdU was also evaluated with a 9L-tk tumor growing in the rat brain. Tumors growing in the right hemisphere of rat brains were irradiated stereotactically with single-dose irradiation. Results: The radiation response of 9L-tk cells was selectively enhanced by antiviral agents relative to nontransduced cells. In the cell culture, when a 24-h drug exposure (20 μg/ml) preceded radiation, the sensitizer enhancement ratio (SER) for BVdU and acyclovir was 1.4 ± 0.1 and 1.3 ± 0.1, respectively. Exposure of cells to 10 μg/ml acyclovir for two 24-h periods both pre- and postirradiation resulted in a SER of 1.6 ± 0.1. In vivo, a significant increase in median survival time of rats with 9L-tk tumors was found when BVdU was administered prior to single-dose irradiation relative to the survival time of similar rats receiving radiation alone. Conclusion: An antiviral agent can enhance cell killing by radiation with selective action in cells transduced with the herpes simplex virus thymidine kinase gene. The results suggest that the three-pronged therapy of HS-tk gene transduction, systemically administered antiviral drug, and stereotactically targeted radiation therapy will improve the effectiveness of radiation therapy for the treatment of radioresistant tumors

  7. Identification of natural antimicrobial agents to treat dengue infection: In vitro analysis of latarcin peptide activity against dengue virus.

    Science.gov (United States)

    Rothan, Hussin A; Bahrani, Hirbod; Rahman, Noorsaadah Abd; Yusof, Rohana

    2014-05-31

    Although there have been considerable advances in the study of dengue virus, no vaccines or anti-dengue drugs are currently available for humans. Therefore, new approaches are necessary for the development of potent anti-dengue drugs. Natural antimicrobial peptides (AMPs) with potent antiviral activities are potential hits-to-leads for antiviral drug discovery. We performed this study to identify and characterise the inhibitory potential of the latarcin peptide (Ltc 1, SMWSGMWRRKLKKLRNALKKKLKGE) against dengue virus replication in infected cells. The Ltc 1 peptide showed a significantly inhibitory effect against the dengue protease NS2B-NS3pro at 37°C, a physiological human temperature, (IC50, 12.68 ± 3.2 μM), and greater inhibitory effect was observed at 40°C, a temperature similar to a high fever (IC50, 6.58 ± 4.1 μM). A greater reduction in viral load (p.f.u./ml) was observed at simultaneous (0.7 ± 0.3 vs. 7.2 ± 0.5 control) and post-treatment (1.8 ± 0.7 vs. 6.8 ± 0.6 control) compared to the pre-treatment (4.5 ± 0.6 vs. 6.9 ± 0.5 control). Treatment with the Ltc 1 peptide reduced the viral RNA in a dose-dependent manner with EC50 values of 8.3 ± 1.2, 7.6 ± 2.7 and 6.8 ± 2.5 μM at 24, 48 and 72 h, respectively. The Ltc 1 peptide exhibited significant inhibitory effects against dengue NS2B-NS3pro and virus replication in the infected cells. Therefore, further investigation is necessary to develop the Ltc 1 peptide as a new anti-dengue therapeutic.

  8. Identification of Antiviral Agents Targeting Hepatitis B Virus Promoter from Extracts of Indonesian Marine Organisms by a Novel Cell-Based Screening Assay

    Directory of Open Access Journals (Sweden)

    Atsuya Yamashita

    2015-11-01

    Full Text Available The current treatments of chronic hepatitis B (CHB face a limited choice of vaccine, antibody and antiviral agents. The development of additional antiviral agents is still needed for improvement of CHB therapy. In this study, we established a screening system in order to identify compounds inhibiting the core promoter activity of hepatitis B virus (HBV. We prepared 80 extracts of marine organisms from the coral reefs of Indonesia and screened them by using this system. Eventually, two extracts showed high inhibitory activity (>95% and low cytotoxicity (66% to 77%. Solvent fractionation, column chromatography and NMR analysis revealed that 3,5-dibromo-2-(2,4-dibromophenoxy-phenol (compound 1 and 3,4,5-tribromo-2-(2,4-dibromophenoxy-phenol (compound 2, which are classified as polybrominated diphenyl ethers (PBDEs, were identified as anti-HBV agents in the extracts. Compounds 1 and 2 inhibited HBV core promoter activity as well as HBV production from HepG2.2.15.7 cells in a dose-dependent manner. The EC50 values of compounds 1 and 2 were 0.23 and 0.80 µM, respectively, while selectivity indexes of compound 1 and 2 were 18.2 and 12.8, respectively. These results suggest that our cell-based HBV core promoter assay system is useful to determine anti-HBV compounds, and that two PBDE compounds are expected to be candidates of lead compounds for the development of anti-HBV drugs.

  9. Causal Diagrams for Empirical Research

    OpenAIRE

    Pearl, Judea

    1994-01-01

    The primary aim of this paper is to show how graphical models can be used as a mathematical language for integrating statistical and subject-matter information. In particular, the paper develops a principled, nonparametric framework for causal inference, in which diagrams are queried to determine if the assumptions available are sufficient for identifiying causal effects from non-experimental data. If so the diagrams can be queried to produce mathematical expressions for causal effects in ter...

  10. Causality Statistical Perspectives and Applications

    CERN Document Server

    Berzuini, Carlo; Bernardinell, Luisa

    2012-01-01

    A state of the art volume on statistical causality Causality: Statistical Perspectives and Applications presents a wide-ranging collection of seminal contributions by renowned experts in the field, providing a thorough treatment of all aspects of statistical causality. It covers the various formalisms in current use, methods for applying them to specific problems, and the special requirements of a range of examples from medicine, biology and economics to political science. This book:Provides a clear account and comparison of formal languages, concepts and models for statistical causality. Addr

  11. Causal electromagnetic interaction equations

    International Nuclear Information System (INIS)

    Zinoviev, Yury M.

    2011-01-01

    For the electromagnetic interaction of two particles the relativistic causal quantum mechanics equations are proposed. These equations are solved for the case when the second particle moves freely. The initial wave functions are supposed to be smooth and rapidly decreasing at the infinity. This condition is important for the convergence of the integrals similar to the integrals of quantum electrodynamics. We also consider the singular initial wave functions in the particular case when the second particle mass is equal to zero. The discrete energy spectrum of the first particle wave function is defined by the initial wave function of the free-moving second particle. Choosing the initial wave functions of the free-moving second particle it is possible to obtain a practically arbitrary discrete energy spectrum.

  12. Structural Equations and Causal Explanations: Some Challenges for Causal SEM

    Science.gov (United States)

    Markus, Keith A.

    2010-01-01

    One common application of structural equation modeling (SEM) involves expressing and empirically investigating causal explanations. Nonetheless, several aspects of causal explanation that have an impact on behavioral science methodology remain poorly understood. It remains unclear whether applications of SEM should attempt to provide complete…

  13. Expert Causal Reasoning and Explanation.

    Science.gov (United States)

    Kuipers, Benjamin

    The relationship between cognitive psychologists and researchers in artificial intelligence carries substantial benefits for both. An ongoing investigation in causal reasoning in medical problem solving systems illustrates this interaction. This paper traces a dialectic of sorts in which three different types of causal resaoning for medical…

  14. Re-thinking local causality

    NARCIS (Netherlands)

    Friederich, Simon

    There is widespread belief in a tension between quantum theory and special relativity, motivated by the idea that quantum theory violates J. S. Bell's criterion of local causality, which is meant to implement the causal structure of relativistic space-time. This paper argues that if one takes the

  15. Covariation in Natural Causal Induction.

    Science.gov (United States)

    Cheng, Patricia W.; Novick, Laura R.

    1991-01-01

    Biases and models usually offered by cognitive and social psychology and by philosophy to explain causal induction are evaluated with respect to focal sets (contextually determined sets of events over which covariation is computed). A probabilistic contrast model is proposed as underlying covariation computation in natural causal induction. (SLD)

  16. Paradoxical Behavior of Granger Causality

    Science.gov (United States)

    Witt, Annette; Battaglia, Demian; Gail, Alexander

    2013-03-01

    Granger causality is a standard tool for the description of directed interaction of network components and is popular in many scientific fields including econometrics, neuroscience and climate science. For time series that can be modeled as bivariate auto-regressive processes we analytically derive an expression for spectrally decomposed Granger Causality (SDGC) and show that this quantity depends only on two out of four groups of model parameters. Then we present examples of such processes whose SDGC expose paradoxical behavior in the sense that causality is high for frequency ranges with low spectral power. For avoiding misinterpretations of Granger causality analysis we propose to complement it by partial spectral analysis. Our findings are illustrated by an example from brain electrophysiology. Finally, we draw implications for the conventional definition of Granger causality. Bernstein Center for Computational Neuroscience Goettingen

  17. On causality of extreme events

    Directory of Open Access Journals (Sweden)

    Massimiliano Zanin

    2016-06-01

    Full Text Available Multiple metrics have been developed to detect causality relations between data describing the elements constituting complex systems, all of them considering their evolution through time. Here we propose a metric able to detect causality within static data sets, by analysing how extreme events in one element correspond to the appearance of extreme events in a second one. The metric is able to detect non-linear causalities; to analyse both cross-sectional and longitudinal data sets; and to discriminate between real causalities and correlations caused by confounding factors. We validate the metric through synthetic data, dynamical and chaotic systems, and data representing the human brain activity in a cognitive task. We further show how the proposed metric is able to outperform classical causality metrics, provided non-linear relationships are present and large enough data sets are available.

  18. Association between respiratory infections in early life and later asthma is independent of virus type

    DEFF Research Database (Denmark)

    Bønnelykke, Klaus; Vissing, Nadja Hawwa; Sevelsted, Astrid

    2015-01-01

    associated with increased risk of asthma by age 7 years with similar odds ratios for all viruses and pathogenic bacteria. After adjustment for the frequency of respiratory episodes, the particular triggers were no longer associated with asthma. CONCLUSION: The number of respiratory episodes in the first......BACKGROUND: Lower respiratory tract infections in the first years of life are associated with later asthma, and this observation has led to a focus on the potential causal role of specific respiratory viruses, such as rhinoviruses and respiratory syncytial virus, in asthma development. However......, many respiratory viruses and bacteria trigger similar respiratory symptoms and it is possible that the important risk factors for asthma are the underlying susceptibility to infection and the exaggerated reaction to such triggers rather than the particular triggering agent. OBJECTIVE: We sought...

  19. Advances in Virus-Directed Therapeutics against Epstein-Barr Virus-Associated Malignancies

    Directory of Open Access Journals (Sweden)

    Sajal K. Ghosh

    2012-01-01

    Full Text Available Epstein-Barr virus (EBV is the causal agent in the etiology of Burkitt’s lymphoma and nasopharyngeal carcinoma and is also associated with multiple human malignancies, including Hodgkin’s and non-Hodgkin’s lymphoma, and posttransplantation lymphoproliferative disease, as well as sporadic cancers of other tissues. A causal relationship of EBV to these latter malignancies remains controversial, although the episomic EBV genome in most of these cancers is clonal, suggesting infection very early in the development of the tumor and a possible role for EBV in the genesis of these diseases. Furthermore, the prognosis of these tumors is invariably poor when EBV is present, compared to their EBV-negative counterparts. The physical presence of EBV in these tumors represents a potential “tumor-specific” target for therapeutic approaches. While treatment options for other types of herpesvirus infections have evolved and improved over the last two decades, however, therapies directed at EBV have lagged. A major constraint to pharmacological intervention is the shift from lytic infection to a latent pattern of gene expression, which persists in those tumors associated with the virus. In this paper we provide a brief account of new virus-targeted therapeutic approaches against EBV-associated malignancies.

  20. Neural Correlates of Causal Power Judgments

    Directory of Open Access Journals (Sweden)

    Denise Dellarosa Cummins

    2014-12-01

    Full Text Available Causal inference is a fundamental component of cognition and perception. Probabilistic theories of causal judgment (most notably causal Bayes networks derive causal judgments using metrics that integrate contingency information. But human estimates typically diverge from these normative predictions. This is because human causal power judgments are typically strongly influenced by beliefs concerning underlying causal mechanisms, and because of the way knowledge is retrieved from human memory during the judgment process. Neuroimaging studies indicate that the brain distinguishes causal events from mere covariation, and between perceived and inferred causality. Areas involved in error prediction are also activated, implying automatic activation of possible exception cases during causal decision-making.

  1. Clear message for causality

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, Aephraim M. [Institute for Experimental Physics, University of Vienna, Vienna (Austria)

    2003-12-01

    Experiment confirms that information cannot be transmitted faster than the speed of light. Ever since Einstein stated that nothing can travel faster than light, physicists have delighted in finding exceptions. One after another, observations of such 'superluminal' propagation have been made. However, while some image or pattern- such as the motion of a spotlight projected on a distant wall - might have appeared to travel faster than light, it seemed that there was no way to use the superluminal effect to transmit energy or information. In recent years, the superluminal propagation of light pulses through certain media has led to renewed controversy. In 1995, for example, Guenther Nimtz of the University of Cologne encoded Mozart's 40th Symphony on a microwave beam, which he claimed to have transmitted at a speed faster than light. Others maintain that such a violation of Einstein's speed limit would wreak havoc on our most fundamental ideas about causality, allowing an effect to precede its cause. Relativity teaches us that sending a signal faster than light would be equivalent to sending it backwards in time. (U.K.)

  2. Causal Rasch models

    Directory of Open Access Journals (Sweden)

    A. Jackson Stenner

    2013-08-01

    Full Text Available Rasch’s unidimensional models for measurement show how to connect object measures (e.g., reader abilities, measurement mechanisms (e.g., machine-generated cloze reading items, and observational outcomes (e.g., counts correct on reading instruments. Substantive theory shows what interventions or manipulations to the measurement mechanism can be traded off against a change to the object measure to hold the observed outcome constant. A Rasch model integrated with a substantive theory dictates the form and substance of permissible interventions. Rasch analysis, absent construct theory and an associated specification equation, is a black box in which understanding may be more illusory than not. Finally, the quantitative hypothesis can be tested by comparing theory-based trade-off relations with observed trade-off relations. Only quantitative variables (as measured support such trade-offs. Note that to test the quantitative hypothesis requires more than manipulation of the algebraic equivalencies in the Rasch model or descriptively fitting data to the model. A causal Rasch model involves experimental intervention/manipulation on either reader ability or text complexity or a conjoint intervention on both simultaneously to yield a successful prediction of the resultant observed outcome (count correct. We conjecture that when this type of manipulation is introduced for individual reader text encounters and model predictions are consistent with observations, the quantitative hypothesis is sustained.

  3. Causal Rasch models.

    Science.gov (United States)

    Stenner, A Jackson; Fisher, William P; Stone, Mark H; Burdick, Donald S

    2013-01-01

    Rasch's unidimensional models for measurement show how to connect object measures (e.g., reader abilities), measurement mechanisms (e.g., machine-generated cloze reading items), and observational outcomes (e.g., counts correct on reading instruments). Substantive theory shows what interventions or manipulations to the measurement mechanism can be traded off against a change to the object measure to hold the observed outcome constant. A Rasch model integrated with a substantive theory dictates the form and substance of permissible interventions. Rasch analysis, absent construct theory and an associated specification equation, is a black box in which understanding may be more illusory than not. Finally, the quantitative hypothesis can be tested by comparing theory-based trade-off relations with observed trade-off relations. Only quantitative variables (as measured) support such trade-offs. Note that to test the quantitative hypothesis requires more than manipulation of the algebraic equivalencies in the Rasch model or descriptively fitting data to the model. A causal Rasch model involves experimental intervention/manipulation on either reader ability or text complexity or a conjoint intervention on both simultaneously to yield a successful prediction of the resultant observed outcome (count correct). We conjecture that when this type of manipulation is introduced for individual reader text encounters and model predictions are consistent with observations, the quantitative hypothesis is sustained.

  4. Causal Rasch models

    Science.gov (United States)

    Stenner, A. Jackson; Fisher, William P.; Stone, Mark H.; Burdick, Donald S.

    2013-01-01

    Rasch's unidimensional models for measurement show how to connect object measures (e.g., reader abilities), measurement mechanisms (e.g., machine-generated cloze reading items), and observational outcomes (e.g., counts correct on reading instruments). Substantive theory shows what interventions or manipulations to the measurement mechanism can be traded off against a change to the object measure to hold the observed outcome constant. A Rasch model integrated with a substantive theory dictates the form and substance of permissible interventions. Rasch analysis, absent construct theory and an associated specification equation, is a black box in which understanding may be more illusory than not. Finally, the quantitative hypothesis can be tested by comparing theory-based trade-off relations with observed trade-off relations. Only quantitative variables (as measured) support such trade-offs. Note that to test the quantitative hypothesis requires more than manipulation of the algebraic equivalencies in the Rasch model or descriptively fitting data to the model. A causal Rasch model involves experimental intervention/manipulation on either reader ability or text complexity or a conjoint intervention on both simultaneously to yield a successful prediction of the resultant observed outcome (count correct). We conjecture that when this type of manipulation is introduced for individual reader text encounters and model predictions are consistent with observations, the quantitative hypothesis is sustained. PMID:23986726

  5. Causal aspects of diffraction

    International Nuclear Information System (INIS)

    Crawford, G.N.

    1981-01-01

    The analysis is directed at a causal description of photon diffraction, which is explained in terms of a wave exerting real forces and providing actual guidance to each quantum of energy. An undulatory PSI wave is associated with each photon, and this wave is assumed to imply more than an informative probability function, so that it actually carries real energy, in much the same way as does an electro-magnetic wave. Whether or not it may be in some way related to the electromagnetic wave is left as a matter of on-going concern. A novel application of the concept of a minimum energy configuration is utilized; that is, a system of energy quanta seeks out relative positions and orientations of least mutual energy, much as an electron seeks its Bohr radius as a position of least mutual energy. Thus the concept implies more a guiding interaction of the PSI waves than an interfering cancellation of these waves. Similar concepts have been suggested by L. de Broglie and D. Bohm

  6. ["Karoshi" and causal relationships].

    Science.gov (United States)

    Hamajima, N

    1992-08-01

    This paper aims to introduce a measure for use by physicians for stating the degree of probable causal relationship for "Karoshi", ie, a sudden death from cerebrovascular diseases or ischemic heart diseases under occupational stresses, as well as to give a brief description for legal procedures associated with worker's compensation and civil trial in Japan. It is a well-used measure in epidemiology, "attributable risk percent (AR%)", which can be applied to describe the extent of contribution to "Karoshi" of the excess occupational burdens the deceased worker was forced to bear. Although several standards such as average occupational burdens for the worker, average occupational burdens for an ordinary worker, burdens in a nonoccupational life, and a complete rest, might be considered for the AR% estimation, the average occupational burdens for an ordinary worker should normally be utilized as a standard for worker's compensation. The adoption of AR% could be helpful for courts to make a consistent judgement whether "Karoshi" cases are compensatable or not.

  7. Pathogenicity of local isolate virus BHV-1 as the aetiological agent of Infectious Bovine Rhinotracheitis in Bali Cattle

    Directory of Open Access Journals (Sweden)

    Rini I Damayanti

    2005-10-01

    Full Text Available Infectious Bovine Rhinotracheitis is a disease of cattle characterised by clinical signs of the upper respiratory tract, reproductive tract and nervous system. A study to define the pathogenicity of four BHV-1 local isolates has been conducted. Fourteen Bali cattle that were free of BHV-1 has been selected and divided into four treatment groups. Each group of three was infected with virus isolate I, II, III and IV respectively with approximately a dose of 108TCID50 /10 ml and two cattle were used as control animals. Isolate I and III were originated from semen from IBR positive bulls number G 867 and G 148 respectively whereas isolate II was collected from vaginal mucosa and isolate IV was from nasal mucosa of IBR positive cattle treated with dexamethasone. Clinical response, gross-pathological and histopathological changes were observed. Immunohistochemical staining was applied to detect the antigen in tissue section. The results show that the BHV-1 local isolates could produce IBR syndrome namely fever and changes in the respiratory and reproductive tracts even though the clinical responses seemed to be disappeared by 21 days PI. Grossly there were hyperaemic nasal and vaginal mucosa and pneumonia whereas histologically there were non suppurative rhinitis, tracheitis, pneumonia and vulvovaginitis. Immunohistochemically the antigen was detected in the nasal concha and trachea. Dexamethasone treatment at 60-64 days PI could produce less severe clinical features and the second necroppsy at 69 days PI also results in less severe pathological responses. The findings also suggest that the pathogenicity of BHV-1 local isolates were as follows: isolates I, II, IV and III.

  8. Structure and Strength in Causal Induction

    Science.gov (United States)

    Griffiths, Thomas L.; Tenenbaum, Joshua B.

    2005-01-01

    We present a framework for the rational analysis of elemental causal induction--learning about the existence of a relationship between a single cause and effect--based upon causal graphical models. This framework makes precise the distinction between causal structure and causal strength: the difference between asking whether a causal relationship…

  9. P3-10: Crossmodal Perceptual Grouping Modulates Subjective Causality between Action and Outcome

    Directory of Open Access Journals (Sweden)

    Takahiro Kawabe

    2012-10-01

    Full Text Available Agents have to determine which external events their action has causally produced. A sensation of causal relation between action and outcome is called subjective causality. Subjective causality has been linked to the comparator model. This model assumes that the brain compares an internal prediction for action outcome with an actual sensory outcome, distinguishing between self and externally produced outcomes depending on spatiotemporal congruency. However, recent studies have expressed some doubt about the idea that subjective causality arises depending solely on the spatiotemporal congruency, suggesting instead that other perceptual/cognitive factors play a critical role in determining subjective causality. We hypothesized that crossmodal grouping between action and outcome contributed to subjective causality. Crossmodal temporal grouping is an essential factor for crossmodal simultaneity judgments with ungrouped crossmodal signals likely to be judged as non-simultaneous. We predicted that subjective causality would decrease when an agent's action was not temporally grouped with action outcome. In the experiment, observers were asked to press a key in order to trigger a display change with some temporal delay. To disrupt temporal grouping between action and outcome, a task-irrelevant visual flash or tone was sometimes presented synchronously with the button press and/or the display change. Subjective causality was decreased when the flash or the tone was coincided with the button press. This demonstrates that perceptual grouping has a key role in determination of subjective causality, a result that is not accounted for by the standard comparator model.

  10. Viruses infecting reptiles.

    Science.gov (United States)

    Marschang, Rachel E

    2011-11-01

    A large number of viruses have been described in many different reptiles. These viruses include arboviruses that primarily infect mammals or birds as well as viruses that are specific for reptiles. Interest in arboviruses infecting reptiles has mainly focused on the role reptiles may play in the epidemiology of these viruses, especially over winter. Interest in reptile specific viruses has concentrated on both their importance for reptile medicine as well as virus taxonomy and evolution. The impact of many viral infections on reptile health is not known. Koch's postulates have only been fulfilled for a limited number of reptilian viruses. As diagnostic testing becomes more sensitive, multiple infections with various viruses and other infectious agents are also being detected. In most cases the interactions between these different agents are not known. This review provides an update on viruses described in reptiles, the animal species in which they have been detected, and what is known about their taxonomic positions.

  11. Viruses Infecting Reptiles

    Directory of Open Access Journals (Sweden)

    Rachel E. Marschang

    2011-11-01

    Full Text Available A large number of viruses have been described in many different reptiles. These viruses include arboviruses that primarily infect mammals or birds as well as viruses that are specific for reptiles. Interest in arboviruses infecting reptiles has mainly focused on the role reptiles may play in the epidemiology of these viruses, especially over winter. Interest in reptile specific viruses has concentrated on both their importance for reptile medicine as well as virus taxonomy and evolution. The impact of many viral infections on reptile health is not known. Koch’s postulates have only been fulfilled for a limited number of reptilian viruses. As diagnostic testing becomes more sensitive, multiple infections with various viruses and other infectious agents are also being detected. In most cases the interactions between these different agents are not known. This review provides an update on viruses described in reptiles, the animal species in which they have been detected, and what is known about their taxonomic positions.

  12. Dynamics of Quantum Causal Structures

    Science.gov (United States)

    Castro-Ruiz, Esteban; Giacomini, Flaminia; Brukner, Časlav

    2018-01-01

    It was recently suggested that causal structures are both dynamical, because of general relativity, and indefinite, because of quantum theory. The process matrix formalism furnishes a framework for quantum mechanics on indefinite causal structures, where the order between operations of local laboratories is not definite (e.g., one cannot say whether operation in laboratory A occurs before or after operation in laboratory B ). Here, we develop a framework for "dynamics of causal structures," i.e., for transformations of process matrices into process matrices. We show that, under continuous and reversible transformations, the causal order between operations is always preserved. However, the causal order between a subset of operations can be changed under continuous yet nonreversible transformations. An explicit example is that of the quantum switch, where a party in the past affects the causal order of operations of future parties, leading to a transition from a channel from A to B , via superposition of causal orders, to a channel from B to A . We generalize our framework to construct a hierarchy of quantum maps based on transformations of process matrices and transformations thereof.

  13. Dynamics of Quantum Causal Structures

    Directory of Open Access Journals (Sweden)

    Esteban Castro-Ruiz

    2018-03-01

    Full Text Available It was recently suggested that causal structures are both dynamical, because of general relativity, and indefinite, because of quantum theory. The process matrix formalism furnishes a framework for quantum mechanics on indefinite causal structures, where the order between operations of local laboratories is not definite (e.g., one cannot say whether operation in laboratory A occurs before or after operation in laboratory B. Here, we develop a framework for “dynamics of causal structures,” i.e., for transformations of process matrices into process matrices. We show that, under continuous and reversible transformations, the causal order between operations is always preserved. However, the causal order between a subset of operations can be changed under continuous yet nonreversible transformations. An explicit example is that of the quantum switch, where a party in the past affects the causal order of operations of future parties, leading to a transition from a channel from A to B, via superposition of causal orders, to a channel from B to A. We generalize our framework to construct a hierarchy of quantum maps based on transformations of process matrices and transformations thereof.

  14. Principal stratification in causal inference.

    Science.gov (United States)

    Frangakis, Constantine E; Rubin, Donald B

    2002-03-01

    Many scientific problems require that treatment comparisons be adjusted for posttreatment variables, but the estimands underlying standard methods are not causal effects. To address this deficiency, we propose a general framework for comparing treatments adjusting for posttreatment variables that yields principal effects based on principal stratification. Principal stratification with respect to a posttreatment variable is a cross-classification of subjects defined by the joint potential values of that posttreatment variable tinder each of the treatments being compared. Principal effects are causal effects within a principal stratum. The key property of principal strata is that they are not affected by treatment assignment and therefore can be used just as any pretreatment covariate. such as age category. As a result, the central property of our principal effects is that they are always causal effects and do not suffer from the complications of standard posttreatment-adjusted estimands. We discuss briefly that such principal causal effects are the link between three recent applications with adjustment for posttreatment variables: (i) treatment noncompliance, (ii) missing outcomes (dropout) following treatment noncompliance. and (iii) censoring by death. We then attack the problem of surrogate or biomarker endpoints, where we show, using principal causal effects, that all current definitions of surrogacy, even when perfectly true, do not generally have the desired interpretation as causal effects of treatment on outcome. We go on to forrmulate estimands based on principal stratification and principal causal effects and show their superiority.

  15. Discrete causal theory emergent spacetime and the causal metric hypothesis

    CERN Document Server

    Dribus, Benjamin F

    2017-01-01

    This book evaluates and suggests potentially critical improvements to causal set theory, one of the best-motivated approaches to the outstanding problems of fundamental physics. Spacetime structure is of central importance to physics beyond general relativity and the standard model. The causal metric hypothesis treats causal relations as the basis of this structure. The book develops the consequences of this hypothesis under the assumption of a fundamental scale, with smooth spacetime geometry viewed as emergent. This approach resembles causal set theory, but differs in important ways; for example, the relative viewpoint, emphasizing relations between pairs of events, and relationships between pairs of histories, is central. The book culminates in a dynamical law for quantum spacetime, derived via generalized path summation.

  16. Causal boundary for stably causal space-times

    International Nuclear Information System (INIS)

    Racz, I.

    1987-12-01

    The usual boundary constructions for space-times often yield an unsatisfactory boundary set. This problem is reviewed and a new solution is proposed. An explicit identification rule is given on the set of the ideal points of the space-time. This construction leads to a satisfactory boundary point set structure for stably causal space-times. The topological properties of the resulting causal boundary construction are examined. For the stably causal space-times each causal curve has a unique endpoint on the boundary set according to the extended Alexandrov topology. The extension of the space-time through the boundary is discussed. To describe the singularities the defined boundary sets have to be separated into two disjoint sets. (D.Gy.) 8 refs

  17. The effect of a non-denaturing detergent and a guanidinium-based inactivation agent on the viability of Ebola virus in mock clinical serum samples.

    Science.gov (United States)

    Burton, J E; Easterbrook, L; Pitman, J; Anderson, D; Roddy, S; Bailey, D; Vipond, R; Bruce, C B; Roberts, A D

    2017-12-01

    The 2014 Ebola outbreak in West Africa required the rapid testing of clinical material for the presence of potentially high titre Ebola virus (EBOV). Safe, fast and effective methods for the inactivation of such clinical samples are required so that rapid diagnostic tests including downstream analysis by RT-qPCR or nucleotide sequencing can be carried out. One of the most commonly used guanidinium - based denaturing agents, AVL (Qiagen) has been shown to fully inactivate EBOV once ethanol is added, however this is not compatible with the use of automated nucleic acid extraction systems. Additional inactivation agents need to be identified that can be used in automated systems. A candidate inactivation agent is Triton X-100, a non-denaturing detergent that is frequently used in clinical nucleic acid extraction procedures and has previously been used for inactivation of EBOV. In this study the effect of 0.1% and 1.0% Triton X-100 (final concentration 0.08% and 0.8% respectively) alone and in combination with AVL on the viability of EBOV (10 6 TCID 50 /ml) spiked into commercially available pooled negative human serum was tested. The presence of viable EBOV in the treated samples was assessed by carrying out three serial passages of the samples in Vero E6 cells (37°C, 5% CO 2 , 1 week for each passage). At the end of each passage the cells were observed for evidence of cytopathic effect and samples were taken for rRT-PCR analysis for the presence of EBOV RNA. Before cell culture cytotoxic components of AVL and Triton X-100 were removed from the samples using size exclusion spin column technology or a hydrophobic adsorbent resin. The results of this study showed that EBOV spiked into human serum was not fully inactivated when treated with either 0.1% (v/v) Triton X-100 for 10 mins or 1.0% (v/v) Triton X-100 for 20 mins (final concentrations 0.08% and 0.8% Triton X-100 respectively). AVL alone also did not consistently provide complete inactivation. Samples treated

  18. Causal boundary for strongly causal spacetimes: Pt. 1

    International Nuclear Information System (INIS)

    Szabados, L.B.

    1989-01-01

    In a previous paper an analysis of the general structure of the causal boundary constructions and a new explicit identification rule, built up from elementary TIP-TIF gluings, were presented. In the present paper we complete our identification by incorporating TIP-TIP and TIF-TIF gluings as well. An asymptotic causality condition is found which, for physically important cases, ensures the uniqueness of the endpoints of the non-spacelike curves in the completed spacetime. (author)

  19. Classical planning and causal implicatures

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Benotti, Luciana

    In this paper we motivate and describe a dialogue manager (called Frolog) which uses classical planning to infer causal implicatures. A causal implicature is a type of Gricean relation implicature, a highly context dependent form of inference. As we shall see, causal implicatures are important...... to generate clarification requests"; as a result we can model task-oriented dialogue as an interactive process locally structured by negotiation of the underlying task. We give several examples of Frolog-human dialog, discuss the limitations imposed by the classical planning paradigm, and indicate...

  20. Functional equations with causal operators

    CERN Document Server

    Corduneanu, C

    2003-01-01

    Functional equations encompass most of the equations used in applied science and engineering: ordinary differential equations, integral equations of the Volterra type, equations with delayed argument, and integro-differential equations of the Volterra type. The basic theory of functional equations includes functional differential equations with causal operators. Functional Equations with Causal Operators explains the connection between equations with causal operators and the classical types of functional equations encountered by mathematicians and engineers. It details the fundamentals of linear equations and stability theory and provides several applications and examples.

  1. Causal Modelling in Evaluation Research.

    Science.gov (United States)

    Winteler, Adolf

    1983-01-01

    A study applied path analysis methods, using new techniques of causal analysis, to the problem of predicting the achievement, dropout rate, and satisfaction of university students. Besides providing explanations, the technique indicates possible remedial measures. (MSE)

  2. Consciousness and the "Causal Paradox"

    OpenAIRE

    Velmans, Max

    1996-01-01

    Viewed from a first-person perspective consciousness appears to be necessary for complex, novel human activity - but viewed from a third-person perspective consciousness appears to play no role in the activity of brains, producing a "causal paradox". To resolve this paradox one needs to distinguish consciousness of processing from consciousness accompanying processing or causing processing. Accounts of consciousness/brain causal interactions switch between first- and third-person perspectives...

  3. The geosimulation of West Nile virus propagation: a multi-agent and climate sensitive tool for risk management in public health

    Directory of Open Access Journals (Sweden)

    Moulin Bernard

    2008-07-01

    Full Text Available Abstract Background Since 1999, the expansion of the West Nile virus (WNV epizooty has led public health authorities to build and operate surveillance systems in North America. These systems are very useful to collect data, but cannot be used to forecast the probable spread of the virus in coming years. Such forecasts, if proven reliable, would permit preventive measures to be put into place at the appropriate level of expected risk and at the appropriate time. It is within this context that the Multi-Agent GeoSimulation approach has been selected to develop a system that simulates the interactions of populations of mosquitoes and birds over space and time in relation to the spread and transmission of WNV. This simulation takes place in a virtual mapping environment representing a large administrative territory (e.g. province, state and carried out under various climate scenarios in order to simulate the effects of vector control measures such as larviciding at scales of 1/20 000 or smaller. Results After setting some hypotheses, a conceptual model and system architecture were developed to describe the population dynamics and interactions of mosquitoes (genus Culex and American crows, which were chosen as the main actors in the simulation. Based on a mathematical compartment model used to simulate the population dynamics, an operational prototype was developed for the Southern part of Quebec (Canada. The system allows users to modify the parameters of the model, to select various climate and larviciding scenarios, to visualize on a digital map the progression (on a weekly or daily basis of the infection in and around the crows' roosts and to generate graphs showing the evolution of the populations. The basic units for visualisation are municipalities. Conclusion In all likelihood this system might be used to support short term decision-making related to WNV vector control measures, including the use of larvicides, according to climatic scenarios

  4. Causal attributions in Brazilian children's reasoning about health and illness

    Directory of Open Access Journals (Sweden)

    Boruchovitch Evely

    2000-01-01

    Full Text Available INTRODUCTION: At a time when a great number of diseases can be prevented by changing one's habits and life style, investigations have focused on understanding what adults and children believe to be desirable health practices and uncovering the factors associated with successful adherence to such practices. For these, causal attributions for health and illness were investigated among 96 Brazilian elementary school students. METHODS: Ninety six subjects, aged 6 to 14, were interviewed individually and their causal attributions were assessed through 14 true-false items (e.g. people stay well [healthy] because they are lucky. The relationship between the children's causal attributions and demographic characteristics were also examined. RESULTS: Overall, the results were consistent with previous researches. "Taking care of oneself" was considered the most important cause of good health. "Viruses and germs" and "lack of self-care" were the most selected causes of illness. Analyses revealed significant relationship between subjects' causal attribution and their age, school grade level, socioeconomic status and gender. CONCLUSIONS: The study findings suggest that there may be more cross-cultural similarities than differences in children's causal attributions for health and illness. Finding ways to help individuals engage in appropriate preventive-maintenance health practices without developing an exaggerated notion that the individuals can control their own health and illness is a challenge which remains to be addressed by further research.

  5. Isolation and characterization of virus of highly pathogenic avian influenza H5 subtype of chicken from outbreaks in Indonesia

    Directory of Open Access Journals (Sweden)

    Agus Wiyono

    2004-03-01

    Full Text Available A study on the isolation and characterization of Highly Pathogenic Avian Influenza of chicken from outbreaks in Indonesia was conducted at Indonesian Research Institute for Veterinary Science. Outbreaks of avian disease had been reported in Indonesia since August 2003 affecting commercial layer, broiler, quail, and ostrich and also native chicken with showing clinical signs such as cyanosis of wattle and comb, nasal discharges and hypersalivation, subcutaneous ptechiae on foot and leg, diarre and sudden high mortality. The aim of this study is to isolate and characterize the causal agent of the disease. Samples of serum, feather follicle, tracheal swab, as well as organs of proventriculus, intestine, caecal tonsil, trachea and lungs were collected from infected animals. Serum samples were tested haemaglutination/haemaglutination inhibition to Newcastle Disease and Egg Drop Syndrome viruses. Isolation of virus of the causal agent of the outbreak was conducted from samples of feather follicle, tracheal swab, and organs using 11 days old specific pathogen free (SPF embryonated eggs. The isolated viruses were then characterised by agar gel precipitation test using swine influenza reference antisera, by haemaglutination inhibition using H1 to H15 reference antisera, and by electron microscope examination. The pathogenicity of the viruses was confirmed by intravenous pathogenicity index test and its culture in Chicken Embryo Fibroblast primary cell culture without addition of trypsin. The study revealed that the causative agent of the outbreaks of avian disease in Indonesia was avian influenza H5 subtype virus based upon serological tests, virus isolation and characterization using swine influenza reference antisera, and electron microscope examination. While subtyping of the viruses using H1 to H15 reference antisera suggested that the virus is very likely to be an avian influenza H5N1 subtype virus. The pathogenicity test confirmed that the viruses

  6. Naturally Occurring Resistance-Associated Variants to Hepatitis C Virus Direct-Acting Antiviral Agents in Treatment-Naive HCV Genotype 6a-Infected Patients

    Directory of Open Access Journals (Sweden)

    Zhanyi Li

    2017-01-01

    Full Text Available Background and Objective. The direct-acting antiviral agents (DAAs antiviral therapy has drastically improved the prognosis of hepatitis C virus (HCV patients. However, the viral drug resistance-associated variants (RAVs can limit the efficacy of DAAs. For the HCV-6a is not the predominant prevalent genotype; the data on the prevalence of naturally occurring RAVs in it is scarce. Our study aims to assess the prevalence of RAVs in treatment-naive HCV-6a patients. Methods. Nested PCR assays were performed on 95 HCV-6a patients to amplify HCV viral regions of NS3, NS5A, and NS5B. Results. In NS3/4A region, we detected Q80K in 95.5% isolates (84/88 and D168E in 2.3% isolates (2/88. In NS5A region, we detected Q30R in 93.2% isolates (82/88, L31M in 4.6% isolates (4/88, and H58P in 6.8% isolates (6/88. In NS5B region, we detected A15G in 2.3% isolates (2/88, S96T in 1.1% isolates (1/88, and S282T in 20.7% isolates (17/88 and we detected I482L in 100% isolates (4/4, V494A in 50% isolates (2/4, and V499A in 100% isolates (4/4. Conclusions. RAVs to DAAs preexist in treatment-naive HCV-6a patients. Further studies should address the issue of the impact of RAVs in response to DAA therapies for HCV-6a patients.

  7. Regression to Causality : Regression-style presentation influences causal attribution

    DEFF Research Database (Denmark)

    Bordacconi, Mats Joe; Larsen, Martin Vinæs

    2014-01-01

    of equivalent results presented as either regression models or as a test of two sample means. Our experiment shows that the subjects who were presented with results as estimates from a regression model were more inclined to interpret these results causally. Our experiment implies that scholars using regression...... models – one of the primary vehicles for analyzing statistical results in political science – encourage causal interpretation. Specifically, we demonstrate that presenting observational results in a regression model, rather than as a simple comparison of means, makes causal interpretation of the results...... more likely. Our experiment drew on a sample of 235 university students from three different social science degree programs (political science, sociology and economics), all of whom had received substantial training in statistics. The subjects were asked to compare and evaluate the validity...

  8. Putting a cap on causality violations in causal dynamical triangulations

    International Nuclear Information System (INIS)

    Ambjoern, Jan; Loll, Renate; Westra, Willem; Zohren, Stefan

    2007-01-01

    The formalism of causal dynamical triangulations (CDT) provides us with a non-perturbatively defined model of quantum gravity, where the sum over histories includes only causal space-time histories. Path integrals of CDT and their continuum limits have been studied in two, three and four dimensions. Here we investigate a generalization of the two-dimensional CDT model, where the causality constraint is partially lifted by introducing branching points with a weight g s , and demonstrate that the system can be solved analytically in the genus-zero sector. The solution is analytic in a neighborhood around weight g s = 0 and cannot be analytically continued to g s = ∞, where the branching is entirely geometric and where one would formally recover standard Euclidean two-dimensional quantum gravity defined via dynamical triangulations or Liouville theory

  9. Bayesian networks improve causal environmental ...

    Science.gov (United States)

    Rule-based weight of evidence approaches to ecological risk assessment may not account for uncertainties and generally lack probabilistic integration of lines of evidence. Bayesian networks allow causal inferences to be made from evidence by including causal knowledge about the problem, using this knowledge with probabilistic calculus to combine multiple lines of evidence, and minimizing biases in predicting or diagnosing causal relationships. Too often, sources of uncertainty in conventional weight of evidence approaches are ignored that can be accounted for with Bayesian networks. Specifying and propagating uncertainties improve the ability of models to incorporate strength of the evidence in the risk management phase of an assessment. Probabilistic inference from a Bayesian network allows evaluation of changes in uncertainty for variables from the evidence. The network structure and probabilistic framework of a Bayesian approach provide advantages over qualitative approaches in weight of evidence for capturing the impacts of multiple sources of quantifiable uncertainty on predictions of ecological risk. Bayesian networks can facilitate the development of evidence-based policy under conditions of uncertainty by incorporating analytical inaccuracies or the implications of imperfect information, structuring and communicating causal issues through qualitative directed graph formulations, and quantitatively comparing the causal power of multiple stressors on value

  10. Causality and analyticity in optics

    International Nuclear Information System (INIS)

    Nussenzveig, H.M.

    In order to provide an overall picture of the broad range of optical phenomena that are directly linked with the concepts of causality and analyticity, the following topics are briefly reviewed, emphasizing recent developments: 1) Derivation of dispersion relations for the optical constants of general linear media from causality. Application to the theory of natural optical activity. 2) Derivation of sum rules for the optical constants from causality and from the short-time response function (asymptotic high-frequency behavior). Average spectral behavior of optical media. Applications. 3) Role of spectral conditions. Analytic properties of coherence functions in quantum optics. Reconstruction theorem.4) Phase retrieval problems. 5) Inverse scattering problems. 6) Solution of nonlinear evolution equations in optics by inverse scattering methods. Application to self-induced transparency. Causality in nonlinear wave propagation. 7) Analytic continuation in frequency and angular momentum. Complex singularities. Resonances and natural-mode expansions. Regge poles. 8) Wigner's causal inequality. Time delay. Spatial displacements in total reflection. 9) Analyticity in diffraction theory. Complex angular momentum theory of Mie scattering. Diffraction as a barrier tunnelling effect. Complex trajectories in optics. (Author) [pt

  11. Hierarchical organisation of causal graphs

    International Nuclear Information System (INIS)

    Dziopa, P.

    1993-01-01

    This paper deals with the design of a supervision system using a hierarchy of models formed by graphs, in which the variables are the nodes and the causal relations between the variables of the arcs. To obtain a representation of the variables evolutions which contains only the relevant features of their real evolutions, the causal relations are completed with qualitative transfer functions (QTFs) which produce roughly the behaviour of the classical transfer functions. Major improvements have been made in the building of the hierarchical organization. First, the basic variables of the uppermost level and the causal relations between them are chosen. The next graph is built by adding intermediary variables to the upper graph. When the undermost graph has been built, the transfer functions parameters corresponding to its causal relations are identified. The second task consists in the upwelling of the information from the undermost graph to the uppermost one. A fusion procedure of the causal relations has been designed to compute the QFTs relevant for each level. This procedure aims to reduce the number of parameters needed to represent an evolution at a high level of abstraction. These techniques have been applied to the hierarchical modelling of nuclear process. (authors). 8 refs., 12 figs

  12. Detección y cuantificación del Potato mop-top virus (PMTV) en Colombia mediante qRT-PCR

    OpenAIRE

    Nevar García Bastidas; Pablo Gutiérrez Sánchez; Mauricio Marín Montoya

    2013-01-01

    El Potato mop-top virus (PMTV) es uno de los virus re-emergentes en cultivos de papa en Colombia. Es transmitido por Spongospora subterranea, el agente causal de la sarna polvosa. La detección del PMTV presenta dificultades debido a su distribución irregular en las plantas, bajo título y movimiento sistémico como ARN desnudo. Con el fin de ampliar el rango de herramientas disponibles para detectar el PMTV en los programas de certificación de tubérculo-semilla, en este estudio se evaluó la pru...

  13. Entropy for theories with indefinite causal structure

    International Nuclear Information System (INIS)

    Markes, Sonia; Hardy, Lucien

    2011-01-01

    Any theory with definite causal structure has a defined past and future, be it defined by light cones or an absolute time scale. Entropy is a concept that has traditionally been reliant on a definite notion of causality. However, without a definite notion of causality, the concept of entropy is not all lost. Indefinite causal structure results from combining probabilistic predictions and dynamical space-time. The causaloid framework lays the mathematical groundwork to be able to treat indefinite causal structure. In this paper, we build on the causaloid mathematics and define a causally-unbiased entropy for an indefinite causal structure. In defining a causally-unbiased entropy, there comes about an emergent idea of causality in the form of a measure of causal connectedness, termed the Q factor.

  14. mediation: R package for causal mediation analysis

    OpenAIRE

    Tingley, Dustin; Yamamoto, Teppei; Hirose, Kentaro; Keele, Luke; Imai, Kosuke

    2012-01-01

    In this paper, we describe the R package mediation for conducting causal mediation analysis in applied empirical research. In many scientific disciplines, the goal of researchers is not only estimating causal effects of a treatment but also understanding the process in which the treatment causally affects the outcome. Causal mediation analysis is frequently used to assess potential causal mechanisms. The mediation package implements a comprehensive suite of statistical tools for conducting su...

  15. A Causal Theory of Modality

    Directory of Open Access Journals (Sweden)

    José Tomás Alvarado

    2009-08-01

    Full Text Available This work presents a causal conception of metaphysical modality in which a state of affairs is metaphysically possible if and only if it can be caused (in the past, the present or the future by current entities. The conception is contrasted with what is called the “combinatorial” conception of modality, in which everything can co-exist with anything else. This work explains how the notion of ‘causality’ should be construed in the causal theory, what difference exists between modalities thus defined from nomological modality, how accessibility relations between possible worlds should be interpreted, and what is the relation between the causal conception and the necessity of origin.

  16. Introductive remarks on causal inference

    Directory of Open Access Journals (Sweden)

    Silvana A. Romio

    2013-05-01

    Full Text Available One of the more challenging issues in epidemiological research is being able to provide an unbiased estimate of the causal exposure-disease effect, to assess the possible etiological mechanisms and the implication for public health. A major source of bias is confounding, which can spuriously create or mask the causal relationship. In the last ten years, methodological research has been developed to better de_ne the concept of causation in epidemiology and some important achievements have resulted in new statistical models. In this review, we aim to show how a technique the well known by statisticians, i.e. standardization, can be seen as a method to estimate causal e_ects, equivalent under certain conditions to the inverse probability treatment weight procedure.

  17. Causal reasoning with mental models

    Science.gov (United States)

    Khemlani, Sangeet S.; Barbey, Aron K.; Johnson-Laird, Philip N.

    2014-01-01

    This paper outlines the model-based theory of causal reasoning. It postulates that the core meanings of causal assertions are deterministic and refer to temporally-ordered sets of possibilities: A causes B to occur means that given A, B occurs, whereas A enables B to occur means that given A, it is possible for B to occur. The paper shows how mental models represent such assertions, and how these models underlie deductive, inductive, and abductive reasoning yielding explanations. It reviews evidence both to corroborate the theory and to account for phenomena sometimes taken to be incompatible with it. Finally, it reviews neuroscience evidence indicating that mental models for causal inference are implemented within lateral prefrontal cortex. PMID:25389398

  18. Causal reasoning with mental models.

    Science.gov (United States)

    Khemlani, Sangeet S; Barbey, Aron K; Johnson-Laird, Philip N

    2014-01-01

    This paper outlines the model-based theory of causal reasoning. It postulates that the core meanings of causal assertions are deterministic and refer to temporally-ordered sets of possibilities: A causes B to occur means that given A, B occurs, whereas A enables B to occur means that given A, it is possible for B to occur. The paper shows how mental models represent such assertions, and how these models underlie deductive, inductive, and abductive reasoning yielding explanations. It reviews evidence both to corroborate the theory and to account for phenomena sometimes taken to be incompatible with it. Finally, it reviews neuroscience evidence indicating that mental models for causal inference are implemented within lateral prefrontal cortex.

  19. Causal reasoning with mental models

    Directory of Open Access Journals (Sweden)

    Sangeet eKhemlani

    2014-10-01

    Full Text Available This paper outlines the model-based theory of causal reasoning. It postulates that the core meanings of causal assertions are deterministic and refer to temporally-ordered sets of possibilities: A causes B to occur means that given A, B occurs, whereas A enables B to occur means that given A, it is possible for B to occur. The paper shows how mental models represent such assertions, and how these models underlie deductive, inductive, and abductive reasoning yielding explanations. It reviews evidence both to corroborate the theory and to account for phenomena sometimes taken to be incompatible with it. Finally, it reviews neuroscience evidence indicating that mental models for causal inference are implemented within lateral prefrontal cortex.

  20. Concepts in causality: chemically induced human urinary bladder cancer

    International Nuclear Information System (INIS)

    Lower, G.M. Jr.

    1982-01-01

    A significant portion of the incidence of human urinary bladder cancer can be attributed to occupational and cultural (tobacco smoking) situations associated with exposures to various arylamines, many of which represent established human carcinogens. A brief historical overview of research in bladder cancer causality indicates that the identification of causal agents and causal mechanism has been approached and rests upon information gathered at the organismal (geographical/historical), cellular, and molecular levels of biologic organization. This viewpoint speaks of a natural evolution within the biomedical sciences; a natural evolution from descriptive approaches to mechanistic approaches; and a natural evolution from more or less independent discipline-oriented approaches to hierarchically organized multidisciplinary approaches. Available information relevant to bladder cancer causality can be readily integrated into general conceptual frameworks to yield a hierarchial view of the natural history of urinary bladder cancer, a view consistent with contemporary natural systems and information theory and perhaps relevant also to other chemically induced epithelial cancers. Such frameworks are useful in appreciating the spatial and temporal boundaries and interrelationships in causality and the conceptual interrelationships within the biomedical sciences. Recent approaches in molecular epidemiology and the assessment of relative individual susceptibility to bladder cancer indicate that such frameworks are useful in forming hypotheses

  1. Granger Causality and Unit Roots

    DEFF Research Database (Denmark)

    Rodríguez-Caballero, Carlos Vladimir; Ventosa-Santaulària, Daniel

    2014-01-01

    The asymptotic behavior of the Granger-causality test under stochastic nonstationarity is studied. Our results confirm that the inference drawn from the test is not reliable when the series are integrated to the first order. In the presence of deterministic components, the test statistic diverges......, eventually rejecting the null hypothesis, even when the series are independent of each other. Moreover, controlling for these deterministic elements (in the auxiliary regressions of the test) does not preclude the possibility of drawing erroneous inferences. Granger-causality tests should not be used under...

  2. Quantum theory and local causality

    CERN Document Server

    Hofer-Szabó, Gábor

    2018-01-01

    This book summarizes the results of research the authors have pursued in the past years on the problem of implementing Bell's notion of local causality in local physical theories and relating it to other important concepts and principles in the foundations of physics such as the Common Cause Principle, Bell's inequalities, the EPR (Einstein-Podolsky-Rosen) scenario, and various other locality and causality concepts. The book is intended for philosophers of science with an interest in the formal background of sciences, philosophers of physics and physicists working in foundation of physics.

  3. [Causal analysis approaches in epidemiology].

    Science.gov (United States)

    Dumas, O; Siroux, V; Le Moual, N; Varraso, R

    2014-02-01

    Epidemiological research is mostly based on observational studies. Whether such studies can provide evidence of causation remains discussed. Several causal analysis methods have been developed in epidemiology. This paper aims at presenting an overview of these methods: graphical models, path analysis and its extensions, and models based on the counterfactual approach, with a special emphasis on marginal structural models. Graphical approaches have been developed to allow synthetic representations of supposed causal relationships in a given problem. They serve as qualitative support in the study of causal relationships. The sufficient-component cause model has been developed to deal with the issue of multicausality raised by the emergence of chronic multifactorial diseases. Directed acyclic graphs are mostly used as a visual tool to identify possible confounding sources in a study. Structural equations models, the main extension of path analysis, combine a system of equations and a path diagram, representing a set of possible causal relationships. They allow quantifying direct and indirect effects in a general model in which several relationships can be tested simultaneously. Dynamic path analysis further takes into account the role of time. The counterfactual approach defines causality by comparing the observed event and the counterfactual event (the event that would have been observed if, contrary to the fact, the subject had received a different exposure than the one he actually received). This theoretical approach has shown limits of traditional methods to address some causality questions. In particular, in longitudinal studies, when there is time-varying confounding, classical methods (regressions) may be biased. Marginal structural models have been developed to address this issue. In conclusion, "causal models", though they were developed partly independently, are based on equivalent logical foundations. A crucial step in the application of these models is the

  4. Current status of Colletotrichum capsici strains, causal agents of ...

    African Journals Online (AJOL)

    Gil

    ASIC, 15e Colloque,. Montpellier 7 p. Dabert M (2006). DNA markers in the phylogenetic of the. Acari. Biol. Lett. 43(2):97-107. Damm U, Woudenberg JHC, Cannon PF, Crous PW (2009). Colletotrichum species with curved conidia from herbaceous hosts. Fungal Divers 39:45-87. Emechebe AM (1986). Cowpea pathology.

  5. Diplodia natalensis Pole Evans, the causal agent of citrus gummosis ...

    African Journals Online (AJOL)

    The isolation media used were 1.5 per cent water agar, 1.5 per cent water agar + nystatin, and 1.5 per cent water agar + benomyl. ... When the isolates were tested for pathogenicity, only D. natalensis induced the disease symptoms in the inoculated 18-month-old rough lemon seedlings which were incubated after ...

  6. Pathogenicity and fungicide sensitivity of the causal agent of ...

    African Journals Online (AJOL)

    The pathogenicity of the fungus and its cross-infection potential were determined on mango, avocado, papaya and banana fruits. The sensitivity of the pathogen to fungicides was determined by assessing radial mycelial growth on potato dextrose agar (PDA) amended with nine different fungicides (Bendazim, Funguran, ...

  7. Genetic recombination in Venturia effusa, causal agent of pecan scab

    Science.gov (United States)

    Venturia effusa causes pecan scab, the most prevalent disease of pecan in the southeastern USA. Mating type idiomorphs were recently characterized and the sexual stage was subsequently produced in vitro. To investigate sexual reproduction and recombination of traits in V. effusa, select isolates wer...

  8. In vitro inhibition of pathogenic Verticillium dahliae, causal agent of ...

    African Journals Online (AJOL)

    SAM

    2014-08-13

    Aug 13, 2014 ... In addition, plant pathogens directly affected through antibiosis and ... Trichoderma strains for antagonistic activity on the fungal pathogen V. ... Five soil sub samples were taken from the area around the healthy potato roots ...

  9. Diplodia natalensis , Pole Evans: a causal agent of citrus gummosis ...

    African Journals Online (AJOL)

    Isolations were made from the barks of gummosis-infected citrus trees from orchards of the University of Ghana Agricultural Research Station at Kade. The isolation media used were 1.5% water agar, 1.5% water agar + nystatin and 1.5% water agar + benomyl. Four isolates including Diplodia natalensis Pole Evans, ...

  10. Causal Reasoning with Mental Models

    Science.gov (United States)

    2014-08-08

    The initial rubric is equivalent to an exclusive disjunction between the two causal assertions. It 488 yields the following two mental models: 489...are 575 important, whereas the functions of artifacts are important (Ahn, 1998). A genetic code is 576 accordingly more critical to being a goat than

  11. Identity, causality, and pronoun ambiguity.

    Science.gov (United States)

    Sagi, Eyal; Rips, Lance J

    2014-10-01

    This article looks at the way people determine the antecedent of a pronoun in sentence pairs, such as: Albert invited Ron to dinner. He spent hours cleaning the house. The experiment reported here is motivated by the idea that such judgments depend on reasoning about identity (e.g., the identity of the he who cleaned the house). Because the identity of an individual over time depends on the causal-historical path connecting the stages of the individual, the correct antecedent will also depend on causal connections. The experiment varied how likely it is that the event of the first sentence (e.g., the invitation) would cause the event of the second (the house cleaning) for each of the two individuals (the likelihood that if Albert invited Ron to dinner, this would cause Albert to clean the house, versus cause Ron to clean the house). Decisions about the antecedent followed causal likelihood. A mathematical model of causal identity accounted for most of the key aspects of the data from the individual sentence pairs. Copyright © 2014 Cognitive Science Society, Inc.

  12. Charged singularities: the causality violation

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-12-01

    A search is made for examples of particle trajectories which, approaching a naked singularity from infinity, make up for lost time before going back to infinity. In the Kerr-Newman metric a whole family of such trajectories is found showing that the causality violation is indeed a non-avoidable pathology.

  13. Entanglement, holography and causal diamonds

    Science.gov (United States)

    de Boer, Jan; Haehl, Felix M.; Heller, Michal P.; Myers, Robert C.

    2016-08-01

    We argue that the degrees of freedom in a d-dimensional CFT can be reorganized in an insightful way by studying observables on the moduli space of causal diamonds (or equivalently, the space of pairs of timelike separated points). This 2 d-dimensional space naturally captures some of the fundamental nonlocality and causal structure inherent in the entanglement of CFT states. For any primary CFT operator, we construct an observable on this space, which is defined by smearing the associated one-point function over causal diamonds. Known examples of such quantities are the entanglement entropy of vacuum excitations and its higher spin generalizations. We show that in holographic CFTs, these observables are given by suitably defined integrals of dual bulk fields over the corresponding Ryu-Takayanagi minimal surfaces. Furthermore, we explain connections to the operator product expansion and the first law of entanglemententropy from this unifying point of view. We demonstrate that for small perturbations of the vacuum, our observables obey linear two-derivative equations of motion on the space of causal diamonds. In two dimensions, the latter is given by a product of two copies of a two-dimensional de Sitter space. For a class of universal states, we show that the entanglement entropy and its spin-three generalization obey nonlinear equations of motion with local interactions on this moduli space, which can be identified with Liouville and Toda equations, respectively. This suggests the possibility of extending the definition of our new observables beyond the linear level more generally and in such a way that they give rise to new dynamically interacting theories on the moduli space of causal diamonds. Various challenges one has to face in order to implement this idea are discussed.

  14. Entanglement, holography and causal diamonds

    Energy Technology Data Exchange (ETDEWEB)

    Boer, Jan de [Institute of Physics, Universiteit van Amsterdam,Science Park 904, 1090 GL Amsterdam (Netherlands); Haehl, Felix M. [Centre for Particle Theory & Department of Mathematical Sciences, Durham University,South Road, Durham DH1 3LE (United Kingdom); Heller, Michal P.; Myers, Robert C. [Perimeter Institute for Theoretical Physics,31 Caroline Street North, Waterloo, Ontario N2L 2Y5 (Canada)

    2016-08-29

    We argue that the degrees of freedom in a d-dimensional CFT can be re-organized in an insightful way by studying observables on the moduli space of causal diamonds (or equivalently, the space of pairs of timelike separated points). This 2d-dimensional space naturally captures some of the fundamental nonlocality and causal structure inherent in the entanglement of CFT states. For any primary CFT operator, we construct an observable on this space, which is defined by smearing the associated one-point function over causal diamonds. Known examples of such quantities are the entanglement entropy of vacuum excitations and its higher spin generalizations. We show that in holographic CFTs, these observables are given by suitably defined integrals of dual bulk fields over the corresponding Ryu-Takayanagi minimal surfaces. Furthermore, we explain connections to the operator product expansion and the first law of entanglement entropy from this unifying point of view. We demonstrate that for small perturbations of the vacuum, our observables obey linear two-derivative equations of motion on the space of causal diamonds. In two dimensions, the latter is given by a product of two copies of a two-dimensional de Sitter space. For a class of universal states, we show that the entanglement entropy and its spin-three generalization obey nonlinear equations of motion with local interactions on this moduli space, which can be identified with Liouville and Toda equations, respectively. This suggests the possibility of extending the definition of our new observables beyond the linear level more generally and in such a way that they give rise to new dynamically interacting theories on the moduli space of causal diamonds. Various challenges one has to face in order to implement this idea are discussed.

  15. The argumentative impact of causal relations

    DEFF Research Database (Denmark)

    Nielsen, Anne Ellerup

    1996-01-01

    such as causality, explanation and justification. In certain types of discourse, causal relations also imply an intentional element. This paper describes the way in which the semantic and pragmatic functions of causal markers can be accounted for in terms of linguistic and rhetorical theories of argumentation.......The semantic relations between and within utterances are marked by the use of connectors and adverbials. One type of semantic relations is causal relations expressed by causal markers such as because, therefore, so, for, etc. Some of these markers cover different types of causal relations...

  16. Ganjam virus.

    Science.gov (United States)

    Sudeep, A B; Jadi, R S; Mishra, A C

    2009-11-01

    Ganjam virus (GANV), a member of genus Nairovirus of family Bunyavirdae is of considerable veterinary importance in India. Though, predominantly tick borne, GANV was also isolated from mosquitoes, man and sheep. Neutralizing and complement fixing antibodies to GANV have been detected in animal and human sera collected from different parts of the country. Thirty three strains of GANV have been isolated from India, mainly from Haemaphysalis ticks. The virus replicated in certain vertebrate and mosquito cell lines and found pathogenic to laboratory animals. One natural infection and five laboratory-acquired infections in men were also reported. GANV is antigenically related to Nairobi sheep disease virus (NSDV) of Africa, which is highly pathogenic for sheep and goats causing 70-90 per cent mortality among the susceptible population. Recent molecular studies have demonstrated that GANV is an Asian variant of NSDV and both these viruses are related to the dreaded Crimean Congo haemorrhagic fever (CCHF) group viruses. The versatility of the virus to replicate in different arthropod species, its ability to infect sheep, goat and man makes it an important zoonotic agent.

  17. Spectral dimension in causal set quantum gravity

    International Nuclear Information System (INIS)

    Eichhorn, Astrid; Mizera, Sebastian

    2014-01-01

    We evaluate the spectral dimension in causal set quantum gravity by simulating random walks on causal sets. In contrast to other approaches to quantum gravity, we find an increasing spectral dimension at small scales. This observation can be connected to the nonlocality of causal set theory that is deeply rooted in its fundamentally Lorentzian nature. Based on its large-scale behaviour, we conjecture that the spectral dimension can serve as a tool to distinguish causal sets that approximate manifolds from those that do not. As a new tool to probe quantum spacetime in different quantum gravity approaches, we introduce a novel dimensional estimator, the causal spectral dimension, based on the meeting probability of two random walkers, which respect the causal structure of the quantum spacetime. We discuss a causal-set example, where the spectral dimension and the causal spectral dimension differ, due to the existence of a preferred foliation. (paper)

  18. On causal nonrelativistic classical electrodynamics

    International Nuclear Information System (INIS)

    Goedecke, G.H.

    1984-01-01

    The differential-difference (DD) motion equations of the causal nonrelativistic classical electrodynamics developed by the author in 1975 are shown to possess only nonrunaway, causal solutions with no discontinuities in particle velocity or position. As an example, the DD equation solution for the problem of an electromagnetic shock incident on an initially stationary charged particle is contrasted with the standard Abraham-Lorentz equation solution. The general Cauchy problem for these DD motion equations is discussed. In general, in order to uniquely determine a solution, the initial data must be more detailed than the standard Cauchy data of initial position and velocity. Conditions are given under which the standard Cauchy data will determine the DD equation solutions to sufficient practical accuracy

  19. Quantum mechanics, relativity and causality

    International Nuclear Information System (INIS)

    Tati, Takao.

    1975-07-01

    In quantum mechanics, the state is prepared by a measurement on a space-like surface sigma. What is that determines the surface sigma on which the measurement prepares the state It is considered either a mechanism proper to the measuring process (apparatus) or a universal property of space-time. In the former case, problems arise, concerning causality or conservation of probability due to that the velocity of reduction of wave-packet is considered to exceed the light velocity. The theory of finite degree of freedom proposed previously belongs to the latter case. In this theory, the surface sigma is restricted to the hyper-plane perpendicular to a universal time-like vector governing causal relations. We propose an experiment to discriminate between the above-mentioned two cases and to test the existence of the universal time-like vector. (auth.)

  20. Causal Set Generator and Action Computer

    OpenAIRE

    Cunningham, William; Krioukov, Dmitri

    2017-01-01

    The causal set approach to quantum gravity has gained traction over the past three decades, but numerical experiments involving causal sets have been limited to relatively small scales. The software suite presented here provides a new framework for the generation and study of causal sets. Its efficiency surpasses previous implementations by several orders of magnitude. We highlight several important features of the code, including the compact data structures, the $O(N^2)$ causal set generatio...

  1. Neutralizing activities of human immunoglobulin derived from donors in Japan against mosquito-borne flaviviruses, Japanese encephalitis virus, West Nile virus, and dengue virus

    Directory of Open Access Journals (Sweden)

    Yunoki M

    2016-07-01

    Full Text Available Mikihiro Yunoki,1-3 Takeshi Kurosu,2 Ritsuko Kubota Koketsu,2,4 Kazuo Takahashi,5 Yoshinobu Okuno,4 Kazuyoshi Ikuta2,4 1Research and Development Division, Japan Blood Products Organization, Tokyo, 2Department of Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, 3Pathogenic Risk Evaluation, Graduate School of Veterinary Medicine, Rakuno Gakuen University, Hokkaido, 4Research and Development Division, The Research Foundation for Microbial Diseases of Osaka University, Kagawa, 5Osaka Prefectural Institute of Public Health, Osaka, Japan Abstract: Japanese encephalitis virus (JEV, West Nile virus (WNV, and dengue virus (DenV are causal agents of Japanese encephalitis, West Nile fever, and dengue fever, respectively. JEV is considered to be indigenized and widespread in Japan, whereas WNV and DenV are not indigenized in Japan. Globulin products seem to reflect the status of the donor population according to antivirus neutralization activity. However, the anti-JEV, -WNV, and -DenV neutralization activities of globulin products derived from donors in Japan have not been clarified. Furthermore, potential candidates for the development of an effective immunotherapeutic drug for encephalitis caused by JEV, WNV, or DenV have also not been identified. Therefore, the aim of this study was to determine the overall status of the donor population in Japan based on globulin products by evaluating anti-JEV, -WNV, and -DenV neutralizing activities of intravenous immunoglobulin. Overall, intravenous immunoglobulin products showed stable neutralizing activity against JEV but showed no or only weak activity against WNV or DenV. These results suggest that the epidemiological level against WNV and DenV in the donor population of Japan is still low, suggesting that these viruses are not yet indigenized. In addition, JEV vaccinations and/or infections in the donor population do not induce a cross-reactive antibody against WNV. Keywords

  2. Modeling of causality with metamaterials

    International Nuclear Information System (INIS)

    Smolyaninov, Igor I

    2013-01-01

    Hyperbolic metamaterials may be used to model a 2 + 1-dimensional Minkowski space–time in which the role of time is played by one of the spatial coordinates. When a metamaterial is built and illuminated with a coherent extraordinary laser beam, the stationary pattern of light propagation inside the metamaterial may be treated as a collection of particle world lines, which represents a complete ‘history’ of this 2 + 1-dimensional space–time. While this model may be used to build interesting space–time analogs, such as metamaterial ‘black holes’ and a metamaterial ‘big bang’, it lacks causality: since light inside the metamaterial may propagate back and forth along the ‘timelike’ spatial coordinate, events in the ‘future’ may affect events in the ‘past’. Here we demonstrate that a more sophisticated metamaterial model may fix this deficiency via breaking the mirror and temporal (PT) symmetries of the original model and producing one-way propagation along the ‘timelike’ spatial coordinate. The resulting 2 + 1-dimensional Minkowski space–time appears to be causal. This scenario may be considered as a metamaterial model of the Wheeler–Feynman absorber theory of causality. (paper)

  3. THE CAUSAL ANALYSIS / DIAGNOSIS DECISION ...

    Science.gov (United States)

    CADDIS is an on-line decision support system that helps investigators in the regions, states and tribes find, access, organize, use and share information to produce causal evaluations in aquatic systems. It is based on the US EPA's Stressor Identification process which is a formal method for identifying causes of impairments in aquatic systems. CADDIS 2007 increases access to relevant information useful for causal analysis and provides methods and tools that practitioners can use to analyze their own data. The new Candidate Cause section provides overviews of commonly encountered causes of impairments to aquatic systems: metals, sediments, nutrients, flow alteration, temperature, ionic strength, and low dissolved oxygen. CADDIS includes new Conceptual Models that illustrate the relationships from sources to stressors to biological effects. An Interactive Conceptual Model for phosphorus links the diagram with supporting literature citations. The new Analyzing Data section helps practitioners analyze their data sets and interpret and use those results as evidence within the USEPA causal assessment process. Downloadable tools include a graphical user interface statistical package (CADStat), and programs for use with the freeware R statistical package, and a Microsoft Excel template. These tools can be used to quantify associations between causes and biological impairments using innovative methods such as species-sensitivity distributions, biological inferenc

  4. Causal structure of analogue spacetimes

    International Nuclear Information System (INIS)

    Barcelo, Carlos; Liberati, Stefano; Sonego, Sebastiano; Visser, Matt

    2004-01-01

    The so-called 'analogue models of general relativity' provide a number of specific physical systems, well outside the traditional realm of general relativity, that nevertheless are well-described by the differential geometry of curved spacetime. Specifically, the propagation of perturbations in these condensed matter systems is described by 'effective metrics' that carry with them notions of 'causal structure' as determined by an exchange of quasi-particles. These quasi-particle-induced causal structures serve as specific examples of what can be done in the presence of a Lorentzian metric without having recourse to the Einstein equations of general relativity. (After all, the underlying analogue model is governed by its own specific physics, not necessarily by the Einstein equations.) In this paper we take a careful look at what can be said about the causal structure of analogue spacetimes, focusing on those containing quasi-particle horizons, both with a view to seeing what is different from standard general relativity, and what the similarities might be. For definiteness, and because the physics is particularly simple to understand, we will phrase much of the discussion in terms of acoustic disturbances in moving fluids, where the underlying physics is ordinary fluid mechanics, governed by the equations of traditional hydrodynamics, and the relevant quasi-particles are the phonons. It must however be emphasized that this choice of example is only for the sake of pedagogical simplicity and that our considerations apply generically to wide classes of analogue spacetimes

  5. Seed Transmission of Beet Curly Top Virus and Beet Curly Top Iran Virus in a Local Cultivar of Petunia in Iran

    Science.gov (United States)

    Anabestani, Ameneh; Behjatnia, Seyed Ali Akbar; Izadpanah, Keramat; Tabein, Saeid

    2017-01-01

    Beet curly top virus (BCTV) and beet curly top Iran virus (BCTIV) are known as the causal agents of curly top disease in beet and several other dicotyledonous plants in Iran. These viruses are transmitted by Circulifer species, and until now, there has been no confirmed report of their seed transmission. A percentage (38.2–78.0%) of the seedlings developed from the seeds of a petunia local cultivar under insect-free conditions showed stunting, interveinal chlorosis, leaf curling, and vein swelling symptoms, and were infected by BCTV when tested by PCR. Presence of BCTV in seed extracts of petunia local cultivar was confirmed by PCR and IC-PCR, followed by sequencing. Agroinoculation of curly top free petunia plants with a BCTV infectious clone resulted in BCTV infection of plants and their developed seeds. These results show the seed infection and transmission of BCTV in a local cultivar of petunia. Similar experiments performed with BCTIV showed that this virus is also seed transmissible in the same cultivar of petunia, although with a lower rate (8.8–18.5%). Seed transmission of curly top viruses may have significant implications in the epidemiology of these viruses. PMID:29035342

  6. Behavioural Pattern of Causality Parameter of Autoregressive ...

    African Journals Online (AJOL)

    In this paper, a causal form of Autoregressive Moving Average process, ARMA (p, q) of various orders and behaviour of the causality parameter of ARMA model is investigated. It is deduced that the behaviour of causality parameter ψi depends on positive and negative values of autoregressive parameter φ and moving ...

  7. Exploring Individual Differences in Preschoolers' Causal Stance

    Science.gov (United States)

    Alvarez, Aubry; Booth, Amy E.

    2016-01-01

    Preschoolers, as a group, are highly attuned to causality, and this attunement is known to facilitate memory, learning, and problem solving. However, recent work reveals substantial individual variability in the strength of children's "causal stance," as demonstrated by their curiosity about and preference for new causal information. In…

  8. Representing Personal Determinants in Causal Structures.

    Science.gov (United States)

    Bandura, Albert

    1984-01-01

    Responds to Staddon's critique of the author's earlier article and addresses issues raised by Staddon's (1984) alternative models of causality. The author argues that it is not the formalizability of causal processes that is the issue but whether cognitive determinants of behavior are reducible to past stimulus inputs in causal structures.…

  9. Causal inference in economics and marketing.

    Science.gov (United States)

    Varian, Hal R

    2016-07-05

    This is an elementary introduction to causal inference in economics written for readers familiar with machine learning methods. The critical step in any causal analysis is estimating the counterfactual-a prediction of what would have happened in the absence of the treatment. The powerful techniques used in machine learning may be useful for developing better estimates of the counterfactual, potentially improving causal inference.

  10. Causal knowledge and reasoning in decision making

    NARCIS (Netherlands)

    Hagmayer, Y.; Witteman, C.L.M.

    2017-01-01

    Normative causal decision theories argue that people should use their causal knowledge in decision making. Based on these ideas, we argue that causal knowledge and reasoning may support and thereby potentially improve decision making based on expected outcomes, narratives, and even cues. We will

  11. The key role of causal explanation in the climate change issue

    Directory of Open Access Journals (Sweden)

    Francesca Pongiglione

    2012-06-01

    Full Text Available The basis for adoption of pro-environment behaviour is the understanding of causal passages within climate dynamics. The understanding of the causes of climate change is necessary in order to be able to take mitigation actions  (the subject needs to be aware of his role as a causal agent. Conversely, the understanding of the consequences of climate change is essential in motivating action (the subject must be aware of the risks caused by it in order to prevent them. The case of ozone depletion confirms this view: the understanding of its causal dynamics played a determining role in people’s behavioural response.

  12. Coxsackievirus B4 as a Causative Agent of Diabetes Mellitus Type 1: Is There a Role of Inefficiently Treated Drinking Water and Sewage in Virus Spreading?

    Science.gov (United States)

    El-Senousy, Waled M; Abdel-Moneim, Adel; Abdel-Latif, Mahmoud; El-Hefnawy, Mohamed H; Khalil, Rehab G

    2018-03-01

    This study proposed to detect the enterovirus (EV) infection in children with type 1 diabetes mellitus (T1D) and to assess the role of insufficiently treated water and sewage as sources of viral spreading. Three hundred and eighty-two serum specimens of children with T1D, one hundred serum specimens of children who did not suffer from T1D as control, and forty-eight water and sewage samples were screened for EV RNA using nested RT-PCR. The number of genome copies and infectious units of EVs in raw and treated sewage and water samples were investigated using real-time (RT)-PCR and plaque assay, respectively. T1D markers [Fasting blood glucose (FBG), HbA1c, and C-peptide], in addition to anti-Coxsackie A & B viruses (CVs A & B) IgG, were measured in control, T1D-negative EV (T1D-EV - ), and T1D-positive EV (T1D-EV + ) children specimens. The prevalence of EV genome was significantly higher in diabetic children (26.2%, 100 out of 382) than the control children (0%, 0 out of 100). FBG and HbA1c in T1D-EV - and T1D-EV + children specimens were significantly higher than those in the control group, while c-peptide in T1D-EV - and T1D-EV + children specimens was significantly lower than that in the control (n = 100; p water and treated sewage samples was 25 and 33.3%, respectively. The prevalence of EV infectious units in drinking water and treated sewage samples was 8.5 and 25%, respectively. Quantification assays were performed to assess the capabilities of both wastewater treatment plants (WWTPs) and water treatment plants (WTPs) to remove EV. The reduction of EV genome in Zenin WWTP ranged from 2 to 4 log 10 , while the reduction of EV infectious units ranged from 1 to 4 log 10 . The reduction of EV genome in El-Giza WTP ranged from 1 to 3 log 10 , while the reduction of EV infectious units ranged from 1 to 2 log 10 . This capability of reduction did not prevent the appearance of infectious EV in treated sewage and drinking water. Plaque purification was performed

  13. A theory of causal learning in children: causal maps and Bayes nets.

    Science.gov (United States)

    Gopnik, Alison; Glymour, Clark; Sobel, David M; Schulz, Laura E; Kushnir, Tamar; Danks, David

    2004-01-01

    The authors outline a cognitive and computational account of causal learning in children. They propose that children use specialized cognitive systems that allow them to recover an accurate "causal map" of the world: an abstract, coherent, learned representation of the causal relations among events. This kind of knowledge can be perspicuously understood in terms of the formalism of directed graphical causal models, or Bayes nets. Children's causal learning and inference may involve computations similar to those for learning causal Bayes nets and for predicting with them. Experimental results suggest that 2- to 4-year-old children construct new causal maps and that their learning is consistent with the Bayes net formalism.

  14. Norms and customs: causally important or causally impotent?

    Science.gov (United States)

    Jones, Todd

    2010-01-01

    In this article, I argue that norms and customs, despite frequently being described as being causes of behavior in the social sciences and ordinary conversation, cannot really cause behavior. Terms like "norms" and the like seem to refer to philosophically disreputable disjunctive properties. More problematically, even if they do not, or even if there can be disjunctive properties after all, I argue that norms and customs still cannot cause behavior. The social sciences would be better off without referring to properties like norms and customs as if they could be causal.

  15. Exceptionalist naturalism: Human agency and the causal order.

    Science.gov (United States)

    Turri, John

    2018-02-01

    This paper addresses a fundamental question in folk metaphysics: How do we ordinarily view human agency? According to the transcendence account, we view human agency as standing outside of the causal order and imbued with exceptional powers. According to a naturalistic account, we view human agency as subject to the same physical laws as other objects and completely open to scientific investigation. According to exceptionalist naturalism, the truth lies somewhere in between: We view human agency as fitting broadly within the causal order while still being exceptional in important respects. In this paper, I report seven experiments designed to decide between these three competing theories. Across a variety of contexts and types of action, participants agreed that human agents can resist outcomes described as inevitable, guaranteed, and causally determined. Participants viewed non-human animal agents similarly, whereas they viewed computers, robots, and simple inanimate objects differently. At the same time, participants judged that human actions are caused by many things, including psychological, neurological, and social events. Overall, in folk metaphysics, human and non-human animals are viewed as exceptional parts of the natural world.

  16. A theory of causal learning in children: Causal maps and Bayes nets

    OpenAIRE

    Gopnik, A; Glymour, C; Sobel, D M; Schulz, L E; Kushnir, T; Danks, D

    2004-01-01

    The authors outline a cognitive and computational account of causal learning in children. They propose that children use specialized cognitive systems that allow them to recover an accurate "causal map" of the world: an abstract, coherent, learned representation of the causal relations among events. This kind of knowledge can be perspicuously understood in terms of the formalism of directed graphical causal models, or Bayes nets. Children's causal learning and inference may involve computatio...

  17. Causal mediation analysis with multiple causally non-ordered mediators.

    Science.gov (United States)

    Taguri, Masataka; Featherstone, John; Cheng, Jing

    2018-01-01

    In many health studies, researchers are interested in estimating the treatment effects on the outcome around and through an intermediate variable. Such causal mediation analyses aim to understand the mechanisms that explain the treatment effect. Although multiple mediators are often involved in real studies, most of the literature considered mediation analyses with one mediator at a time. In this article, we consider mediation analyses when there are causally non-ordered multiple mediators. Even if the mediators do not affect each other, the sum of two indirect effects through the two mediators considered separately may diverge from the joint natural indirect effect when there are additive interactions between the effects of the two mediators on the outcome. Therefore, we derive an equation for the joint natural indirect effect based on the individual mediation effects and their interactive effect, which helps us understand how the mediation effect works through the two mediators and relative contributions of the mediators and their interaction. We also discuss an extension for three mediators. The proposed method is illustrated using data from a randomized trial on the prevention of dental caries.

  18. Characterization of a thymidine kinase-deficient mutant of equine herpesvirus 4 and in vitro susceptibility of the virus to antiviral agents.

    Science.gov (United States)

    Azab, Walid; Tsujimura, Koji; Kato, Kentaro; Arii, Jun; Morimoto, Tomomi; Kawaguchi, Yasushi; Tohya, Yukinobu; Matsumura, Tomio; Akashi, Hiroomi

    2010-02-01

    Equine herpesvirus 4 (EHV-4) is an important equine pathogen that causes respiratory tract disease among horses worldwide. A thymidine kinase (TK)-deletion mutant has been generated by using bacterial artificial chromosome (BAC) technology to investigate the role of TK in pathogenesis. Deletion of TK had virtually no effect on the growth characteristics of WA79DeltaTK in cell culture when compared to the parent virus. Also, virus titers and plaque formation were unaffected in the absence of the TK gene. The sensitivity of EHV-4 to inhibition by acyclovir (ACV) and ganciclovir (GCV) was studied by means of a plaque reduction assay. GCV proved to be more potent and showed a superior anti-EHV-4 activity. On the other hand, ACV showed very poor ability to inhibit EHV-4 replication. As predicted, WA79DeltaTK was insensitive to GCV. Although EHV-4 is normally insensitive to ACV, it showed >20-fold increase in sensitivity when the equine herpesvirus-1 (EHV-1) TK was supplied in trans. Furthermore, both ACV and GCV resulted in a significant reduction of plaque size induced by EHV-4 and 1. Taken together, these data provided direct evidence that GCV is a potent selective inhibitor of EHV-4 and that the virus-encoded TK is an important determinant of the virus susceptibility to nucleoside analogues. Copyright 2009 Elsevier B.V. All rights reserved.

  19. Electrophysiological difference between the representations of causal judgment and associative judgment in semantic memory.

    Science.gov (United States)

    Chen, Qingfei; Liang, Xiuling; Lei, Yi; Li, Hong

    2015-05-01

    Causally related concepts like "virus" and "epidemic" and general associatively related concepts like "ring" and "emerald" are represented and accessed separately. The Evoked Response Potential (ERP) procedure was used to examine the representations of causal judgment and associative judgment in semantic memory. Participants were required to remember a task cue (causal or associative) presented at the beginning of each trial, and assess whether the relationship between subsequently presented words matched the initial task cue. The ERP data showed that an N400 effect (250-450 ms) was more negative for unrelated words than for all related words. Furthermore, the N400 effect elicited by causal relations was more positive than for associative relations in causal cue condition, whereas no significant difference was found in the associative cue condition. The centrally distributed late ERP component (650-750 ms) elicited by the causal cue condition was more positive than for the associative cue condition. These results suggested that the processing of causal judgment and associative judgment in semantic memory recruited different degrees of attentional and executive resources. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. The Functions of Danish Causal Conjunctions

    Directory of Open Access Journals (Sweden)

    Rita Therkelsen

    2004-01-01

    Full Text Available In the article I propose an analysis of the Danish causal conjunctions fordi, siden and for based on the framework of Danish Functional Grammar. As conjunctions they relate two clauses, and their semantics have in common that it indicates a causal relationship between the clauses. The causal conjunctions are different as far as their distribution is concerned; siden conjoins a subordinate clause and a main clause, for conjoins two main clauses, and fordi is able to do both. Methodologically I have based my analysis on these distributional properties comparing siden and fordi conjoining a subordinate and a main clause, and comparing for and fordi conjoining two main clauses, following the thesis that they would establish a causal relationship between different kinds of content. My main findings are that fordi establishes a causal relationship between the events referred to by the two clauses, and the whole utterance functions as a statement of this causal relationship. Siden presupposes such a general causal relationship between the two events and puts forward the causing event as a reason for assuming or wishing or ordering the caused event, siden thus establishes a causal relationship between an event and a speech act. For equally presupposes a general causal relationship between two events and it establishes a causal relationship between speech acts, and fordi conjoining two main clauses is able to do this too, but in this position it also maintains its event-relating ability, the interpretation depending on contextual factors.

  1. Space and time in perceptual causality

    Directory of Open Access Journals (Sweden)

    Benjamin Straube

    2010-04-01

    Full Text Available Inferring causality is a fundamental feature of human cognition that allows us to theorize about and predict future states of the world. Michotte suggested that humans automatically perceive causality based on certain perceptual features of events. However, individual differences in judgments of perceptual causality cast doubt on Michotte’s view. To gain insights in the neural basis of individual difference in the perception of causality, our participants judged causal relationships in animations of a blue ball colliding with a red ball (a launching event while fMRI-data were acquired. Spatial continuity and temporal contiguity were varied parametrically in these stimuli. We did not find consistent brain activation differences between trials judged as caused and those judged as non-caused, making it unlikely that humans have universal instantiation of perceptual causality in the brain. However, participants were slower to respond to and showed greater neural activity for violations of causality, suggesting that humans are biased to expect causal relationships when moving objects appear to interact. Our participants demonstrated considerable individual differences in their sensitivity to spatial and temporal characteristics in perceiving causality. These qualitative differences in sensitivity to time or space in perceiving causality were instantiated in individual differences in activation of the left basal ganglia or right parietal lobe, respectively. Thus, the perception that the movement of one object causes the movement of another is triggered by elemental spatial and temporal sensitivities, which themselves are instantiated in specific distinct neural networks.

  2. Respuesta al glifosato de un aislamiento de Rhizoctonia solani agente causal del anublo de la vaina del arroz, y de cuatro aislamientos de Trichoderma, bajo condiciones in vitro In vitro response of one isolate of Rhizoctonia solani, the pathogen of the rice sheath blight and four isolates of Trichoderma to glyphosate

    Directory of Open Access Journals (Sweden)

    Vargas de Álvarez Amparo

    2002-08-01

    Full Text Available El añublo de la vaina del arroz (Orysa saliva L., cuyo agente causal es Rhizoctonia solani Kuhn, es una de las enfermedades más importantes en el cultivo del arroz en Colombia. En los cultivos de arroz con frecuencia se aplica glifosato ((ácido N-(fosfonometil glicina para controlar las malezas, particularmente el arroz rojo (O. saliva, antes de la siembra del arroz. Observaciones de campo anteriores parecían indicar relación entre el uso intensivo del glifosato y el incremento en la incidencia del añublo de la vaina del arroz. Por tanto, se propuso el presente trabajo con el fin de dilucidar los posibles efectos del glifosato sobre R. solani y Trichoderma sp., conocido éste como antagonista de R. solani. Se determinó, bajo condiciones de laboratorio, el efecto del glifosato en el crecimiento, en medio líquido y sólido PDA, de R. solani y de Trichoderma. Se encontró que la dosis más alta de glifosato sin efecto detrimental sobre R. solani, fue de 300 mg/L y la dosis más baja del herbicida que
    causó la mayor inhibición del crecimiento del hongo fue
    de 2500 mg/L. Por otra parte, no se encontró que el glifosato
    estimulara el crecimiento de R. solani. En teoría, en una aplicación comercial de glifosato de 1,5 Kg ia/ha y asperjando directamente al suelo sin vegetación, el glifosato en el suelo estaría a una concentración de 0,75 mg/Kg de suelo (suponiendo que la capa arable de una hectárea de suelo pesa 2.000.000 de Kg; por tanto, la concentración de glifosato después de una aplicación comercial, está muy por debajo de la concentración a la cual se inicia la reducción del crecimiento de R. solani. Por su parte, la respuesta de Trichoderma al glifosato fue similar a la de R. solani; además, se encontró que el glifosato no afecta la capacidad antagonista de Trichoderma sobre R. sotaní. Estos resultados no apoyan la hipótesis que el glifosato, bajo las condiciones de uso en cultivos de arroz para el control

  3. Causal diagrams in systems epidemiology

    Directory of Open Access Journals (Sweden)

    Joffe Michael

    2012-03-01

    Full Text Available Abstract Methods of diagrammatic modelling have been greatly developed in the past two decades. Outside the context of infectious diseases, systematic use of diagrams in epidemiology has been mainly confined to the analysis of a single link: that between a disease outcome and its proximal determinant(s. Transmitted causes ("causes of causes" tend not to be systematically analysed. The infectious disease epidemiology modelling tradition models the human population in its environment, typically with the exposure-health relationship and the determinants of exposure being considered at individual and group/ecological levels, respectively. Some properties of the resulting systems are quite general, and are seen in unrelated contexts such as biochemical pathways. Confining analysis to a single link misses the opportunity to discover such properties. The structure of a causal diagram is derived from knowledge about how the world works, as well as from statistical evidence. A single diagram can be used to characterise a whole research area, not just a single analysis - although this depends on the degree of consistency of the causal relationships between different populations - and can therefore be used to integrate multiple datasets. Additional advantages of system-wide models include: the use of instrumental variables - now emerging as an important technique in epidemiology in the context of mendelian randomisation, but under-used in the exploitation of "natural experiments"; the explicit use of change models, which have advantages with respect to inferring causation; and in the detection and elucidation of feedback.

  4. Causal diagrams in systems epidemiology.

    Science.gov (United States)

    Joffe, Michael; Gambhir, Manoj; Chadeau-Hyam, Marc; Vineis, Paolo

    2012-03-19

    Methods of diagrammatic modelling have been greatly developed in the past two decades. Outside the context of infectious diseases, systematic use of diagrams in epidemiology has been mainly confined to the analysis of a single link: that between a disease outcome and its proximal determinant(s). Transmitted causes ("causes of causes") tend not to be systematically analysed.The infectious disease epidemiology modelling tradition models the human population in its environment, typically with the exposure-health relationship and the determinants of exposure being considered at individual and group/ecological levels, respectively. Some properties of the resulting systems are quite general, and are seen in unrelated contexts such as biochemical pathways. Confining analysis to a single link misses the opportunity to discover such properties.The structure of a causal diagram is derived from knowledge about how the world works, as well as from statistical evidence. A single diagram can be used to characterise a whole research area, not just a single analysis - although this depends on the degree of consistency of the causal relationships between different populations - and can therefore be used to integrate multiple datasets.Additional advantages of system-wide models include: the use of instrumental variables - now emerging as an important technique in epidemiology in the context of mendelian randomisation, but under-used in the exploitation of "natural experiments"; the explicit use of change models, which have advantages with respect to inferring causation; and in the detection and elucidation of feedback.

  5. Probabilistic causality and radiogenic cancers

    International Nuclear Information System (INIS)

    Groeer, P.G.

    1986-01-01

    A review and scrutiny of the literature on probability and probabilistic causality shows that it is possible under certain assumptions to estimate the probability that a certain type of cancer diagnosed in an individual exposed to radiation prior to diagnosis was caused by this exposure. Diagnosis of this causal relationship like diagnosis of any disease - malignant or not - requires always some subjective judgments by the diagnostician. It is, therefore, illusory to believe that tables based on actuarial data can provide objective estimates of the chance that a cancer diagnosed in an individual is radiogenic. It is argued that such tables can only provide a base from which the diagnostician(s) deviate in one direction or the other according to his (their) individual (consensual) judgment. Acceptance of a physician's diagnostic judgment by patients is commonplace. Similar widespread acceptance of expert judgment by claimants in radiation compensation cases does presently not exist. Judicious use of the present radioepidemiological tables prepared by the Working Group of the National Institutes of Health or of updated future versions of similar tables may improve the situation. 20 references

  6. Biological Agents

    Science.gov (United States)

    ... E-Tools Safety and Health Topics / Biological Agents Biological Agents This page requires that javascript be enabled ... 202) 693-2300 if additional assistance is required. Biological Agents Menu Overview In Focus: Ebola Frederick A. ...

  7. An agent-based model of dengue virus transmission shows how multiple uncertainties about vaccine efficacy influence public health impact projections

    OpenAIRE

    Scott, Thomas; Elder, John; Perkins, Alex; Reiner, Robert; Stoddard, Steven; Morrison, Amy; Kitron, Uriel; Vazquez-Prokopec, Gonzalo; Scott, Thomas; Vazquez-Prokopec, Gonzalo; Smith, David; Espana, Guido; Verma, Amit; Liebman, Kelly; Paz-Soldan, Valerie

    2018-01-01

    Given the limited effectiveness of strategies based solely on vector control to reduce dengue virus (DENV) transmission, it is expected that an effective vaccine could play a pivotal role in reducing the global disease burden of dengue. Of several dengue vaccines under development, Dengvaxia® from Sanofi Pasteur recently became the first to become licensed in select countries and to achieve WHO recommendation for use in certain settings, despite the fact that a number of uncertainties about i...

  8. Linear causal modeling with structural equations

    CERN Document Server

    Mulaik, Stanley A

    2009-01-01

    Emphasizing causation as a functional relationship between variables that describe objects, Linear Causal Modeling with Structural Equations integrates a general philosophical theory of causation with structural equation modeling (SEM) that concerns the special case of linear causal relations. In addition to describing how the functional relation concept may be generalized to treat probabilistic causation, the book reviews historical treatments of causation and explores recent developments in experimental psychology on studies of the perception of causation. It looks at how to perceive causal

  9. Causal relationship: a new tool for the causal characterization of Lorentzian manifolds

    International Nuclear Information System (INIS)

    Garcia-Parrado, Alfonso; Senovilla, Jose M M

    2003-01-01

    We define and study a new kind of relation between two diffeomorphic Lorentzian manifolds called a causal relation, which is any diffeomorphism characterized by mapping every causal vector of the first manifold onto a causal vector of the second. We perform a thorough study of the mathematical properties of causal relations and prove in particular that two given Lorentzian manifolds (say V and W) may be causally related only in one direction (say from V to W, but not from W to V). This leads us to the concept of causally equivalent (or isocausal in short) Lorentzian manifolds as those mutually causally related and to a definition of causal structure over a differentiable manifold as the equivalence class formed by isocausal Lorentzian metrics upon it. Isocausality is a more general concept than the conformal relationship, because we prove the remarkable result that a conformal relation φ is characterized by the fact of being a causal relation of the particular kind in which both φ and φ -1 are causal relations. Isocausal Lorentzian manifolds are mutually causally compatible, they share some important causal properties, and there are one-to-one correspondences, which are sometimes non-trivial, between several classes of their respective future (and past) objects. A more important feature is that they satisfy the same standard causality constraints. We also introduce a partial order for the equivalence classes of isocausal Lorentzian manifolds providing a classification of all the causal structures that a given fixed manifold can have. By introducing the concept of causal extension we put forward a new definition of causal boundary for Lorentzian manifolds based on the concept of isocausality, and thereby we generalize the traditional Penrose constructions of conformal infinity, diagrams and embeddings. In particular, the concept of causal diagram is given. Many explicit clarifying examples are presented throughout the paper

  10. Space-time as a causal set

    International Nuclear Information System (INIS)

    Bombelli, L.; Lee, J.; Meyer, D.; Sorkin, R.D.

    1987-01-01

    We propose that space-time at the smallest scales is in reality a causal set: a locally finite set of elements endowed with a partial order corresponding to the macroscopic relation that defines past and future. We explore how a Lorentzian manifold can approximate a causal set, noting in particular that the thereby defined effective dimensionality of a given causal set can vary with length scale. Finally, we speculate briefly on the quantum dynamics of causal sets, indicating why an appropriate choice of action can reproduce general relativity in the classical limit

  11. Amodal causal capture in the tunnel effect.

    Science.gov (United States)

    Bae, Gi Yeul; Flombaum, Jonathan I

    2011-01-01

    In addition to identifying individual objects in the world, the visual system must also characterize the relationships between objects, for instance when objects occlude one another or cause one another to move. Here we explored the relationship between perceived causality and occlusion. Can one perceive causality in an occluded location? In several experiments, observers judged whether a centrally presented event involved a single object passing behind an occluder, or one object causally launching another (out of view and behind the occluder). With no additional context, the centrally presented event was typically judged as a non-causal pass, even when the occluding and disoccluding objects were different colors--an illusion known as the 'tunnel effect' that results from spatiotemporal continuity. However, when a synchronized context event involved an unambiguous causal launch, participants perceived a causal launch behind the occluder. This percept of an occluded causal interaction could also be driven by grouping and synchrony cues in the absence of any explicitly causal interaction. These results reinforce the hypothesis that causality is an aspect of perception. It is among the interpretations of the world that are independently available to vision when resolving ambiguity, and that the visual system can 'fill in' amodally.

  12. Electromagnetic pulses, localized and causal

    Science.gov (United States)

    Lekner, John

    2018-01-01

    We show that pulse solutions of the wave equation can be expressed as time Fourier superpositions of scalar monochromatic beam wave functions (solutions of the Helmholtz equation). This formulation is shown to be equivalent to Bateman's integral expression for solutions of the wave equation, for axially symmetric solutions. A closed-form one-parameter solution of the wave equation, containing no backward-propagating parts, is constructed from a beam which is the tight-focus limit of two families of beams. Application is made to transverse electric and transverse magnetic pulses, with evaluation of the energy, momentum and angular momentum for a pulse based on the general localized and causal form. Such pulses can be represented as superpositions of photons. Explicit total energy and total momentum values are given for the one-parameter closed-form pulse.

  13. Quantum retrodiction and causality principle

    International Nuclear Information System (INIS)

    Shirokov, M.I.

    1994-01-01

    Quantum mechanics is factually a predictive science. But quantum retrodiction may also be needed, e.g., for the experimental verification of the validity of the Schroedinger equation for the wave function in the past if the present state is given. It is shown that in the retrodictive analog of the prediction the measurement must be replaced by another physical process called the retromeasurement. In this process, the reduction of a state vector into eigenvectors of a measured observable must proceed in the opposite direction of time as compared to the usual reduction. Examples of such processes are unknown. Moreover, they are shown to be forbidden by the causality principle stating that the later event cannot influence the earlier one. So quantum retrodiction seems to be unrealizable. It is demonstrated that the approach to the retrodiction given by S.Watanabe and F.Belinfante must be considered as an unsatisfactory ersatz of retrodicting. 20 refs., 3 figs

  14. The gut microbiota and obesity: from correlation to causality.

    Science.gov (United States)

    Zhao, Liping

    2013-09-01

    The gut microbiota has been linked with chronic diseases such as obesity in humans. However, the demonstration of causality between constituents of the microbiota and specific diseases remains an important challenge in the field. In this Opinion article, using Koch's postulates as a conceptual framework, I explore the chain of causation from alterations in the gut microbiota, particularly of the endotoxin-producing members, to the development of obesity in both rodents and humans. I then propose a strategy for identifying the causative agents of obesity in the human microbiota through a combination of microbiome-wide association studies, mechanistic analysis of host responses and the reproduction of diseases in gnotobiotic animals.

  15. Causal ubiquity in quantum physics. A superluminal and local-causal physical ontology

    International Nuclear Information System (INIS)

    Neelamkavil, Raphael

    2014-01-01

    A fixed highest criterial velocity (of light) in STR (special theory of relativity) is a convention for a layer of physical inquiry. QM (Quantum Mechanics) avoids action-at-a-distance using this concept, but accepts non-causality and action-at-a-distance in EPR (Einstein-Podolsky-Rosen-Paradox) entanglement experiments. Even in such allegedly [non-causal] processes, something exists processually in extension-motion, between the causal and the [non-causal]. If STR theoretically allows real-valued superluminal communication between EPR entangled particles, quantum processes become fully causal. That is, the QM world is sub-luminally, luminally and superluminally local-causal throughout, and the Law of Causality is ubiquitous in the micro-world. Thus, ''probabilistic causality'' is a merely epistemic term.

  16. Causal ubiquity in quantum physics. A superluminal and local-causal physical ontology

    Energy Technology Data Exchange (ETDEWEB)

    Neelamkavil, Raphael

    2014-07-01

    A fixed highest criterial velocity (of light) in STR (special theory of relativity) is a convention for a layer of physical inquiry. QM (Quantum Mechanics) avoids action-at-a-distance using this concept, but accepts non-causality and action-at-a-distance in EPR (Einstein-Podolsky-Rosen-Paradox) entanglement experiments. Even in such allegedly [non-causal] processes, something exists processually in extension-motion, between the causal and the [non-causal]. If STR theoretically allows real-valued superluminal communication between EPR entangled particles, quantum processes become fully causal. That is, the QM world is sub-luminally, luminally and superluminally local-causal throughout, and the Law of Causality is ubiquitous in the micro-world. Thus, ''probabilistic causality'' is a merely epistemic term.

  17. METODE PENAPISAN CABAI (CAPSICUM ANNUUM L. UNTUK KETAHANAN TERHADAP CHILLI VEINAL MOTTLE VIRUS (Chi VMV DAN CUCUMBER MOSAIC VIRUS (CMV

    Directory of Open Access Journals (Sweden)

    Latifah, Sri Hendrastuti Hidayat, dan Sriani Sujiprihati .

    2011-11-01

    Full Text Available Screening Method for Chilli Veinal Mottle Virus  (Chi VMV and Cucumber Mosaic Virus  (CMV Resistance in Chillipepper.  ChiVMV and CMV have been reported as the causal agents of main diseases in chillipepper in Indonesia and other Asian countries.  Mix infection of this two viruses was commonly occurred in the field, causing severe disease .  The use of resistance varieties has been proposed for dealing with the yield losses causing by  the viruses.  Breeding program is undergoing for development of chillipepper varieties resistant to ChiVMV and CMV.  Methodology for routine screening activity of chillipepper for resistance to both ChiVMV and CMV needs to be established. This research was conducted in Cikabayan Glass House and Plant Virology Laboratory, Plant Protection Department, Bogor Agricultural University from May 2006 to June 2007. Aim of the research was to develop screening method for simultaneous infection by the two viruses, ChiVMV and CMV.  Inoculation of ChiVMV and CMV was done by single inoculation or repetitive inoculation methods.  In both methods, ChiVMV and CMV were inoculated in different sequences, either ChiVMV or CMV first.  The result showed that incubation period was shorter when CMV was inoculated in advance both in single and repetitive inoculation method.  Mosaic, mottle and malformation type symptom was observed in infected plants. Based on disease incidence, infection of ChiVMV was higher compared to CMV in repetitive inoculation as well as in single inoculation.  Repetitive inoculation methods with virus sequence ChiVMV-CMV-ChiVMV-CMV  was selected for resistance evaluation of chillipepper genotypes.

  18. Cytomegalovirus and BK-Virus co-infection of a clinically non-functioning adrenal adenoma: innocent bystanders or new pathogenetic agents?

    Science.gov (United States)

    Pomara, G; Cappello, F; Barzon, L; Morelli, G; Rappa, F; Benvegna, L; Giannarini, G; Palù, G; Selli, C

    2006-01-01

    We report a case of a 64-year-old woman who underwent left adrenalectomy with removal of a 8,5 cm clinically non-functioning adrenocortical adenoma and a 4-cm myelolipoma. Molecular testing for viral infection demonstrated the presence of cytomegalovirus (CMV) DNA sequences in the adrenal adenoma, but not in the myelolipoma (confirmed by immunohistochemistry). Moreover, the adrenal adenoma was also positive for parvovirus B19, and both adrenal tumor samples were positive for polyomavirus BK (BKV) and adenovirus DNA sequences. This is the first report of co-infection of an adrenocortical adenoma by CMV and BKV. The role of these viruses in adrenal tumorigenesis was postulated.

  19. A Theory of Causal Learning in Children: Causal Maps and Bayes Nets

    Science.gov (United States)

    Gopnik, Alison; Glymour, Clark; Sobel, David M.; Schulz, Laura E.; Kushnir, Tamar; Danks, David

    2004-01-01

    The authors outline a cognitive and computational account of causal learning in children. They propose that children use specialized cognitive systems that allow them to recover an accurate "causal map" of the world: an abstract, coherent, learned representation of the causal relations among events. This kind of knowledge can be perspicuously…

  20. Further properties of causal relationship: causal structure stability, new criteria for isocausality and counterexamples

    International Nuclear Information System (INIS)

    Garcia-Parrado, Alfonso; Sanchez, Miguel

    2005-01-01

    Recently (Garcia-Parrado and Senovilla 2003 Class. Quantum Grav. 20 625-64) the concept of causal mapping between spacetimes, essentially equivalent in this context to the chronological map defined in abstract chronological spaces, and the related notion of causal structure, have been introduced as new tools to study causality in Lorentzian geometry. In the present paper, these tools are further developed in several directions such as (i) causal mappings-and, thus, abstract chronological ones-do not preserve two levels of the standard hierarchy of causality conditions (however, they preserve the remaining levels as shown in the above reference), (ii) even though global hyperbolicity is a stable property (in the set of all time-oriented Lorentzian metrics on a fixed manifold), the causal structure of a globally hyperbolic spacetime can be unstable against perturbations; in fact, we show that the causal structures of Minkowski and Einstein static spacetimes remain stable, whereas that of de Sitter becomes unstable, (iii) general criteria allow us to discriminate different causal structures in some general spacetimes (e.g. globally hyperbolic, stationary standard); in particular, there are infinitely many different globally hyperbolic causal structures (and thus, different conformal ones) on R 2 (iv) plane waves with the same number of positive eigenvalues in the frequency matrix share the same causal structure and, thus, they have equal causal extensions and causal boundaries

  1. Molecular characterization and experimental host range of an isolate of Wissadula golden mosaic St. Thomas virus.

    Science.gov (United States)

    Collins, A M; Mujaddad-ur-Rehman, Malik; Brown, J K; Reddy, C; Wang, A; Fondong, V; Roye, M E

    2009-12-01

    conditions, confirming that this virus is a causal agent of Wissadula yellow mosaic disease in W. amplissima.

  2. Campbell's and Rubin's Perspectives on Causal Inference

    Science.gov (United States)

    West, Stephen G.; Thoemmes, Felix

    2010-01-01

    Donald Campbell's approach to causal inference (D. T. Campbell, 1957; W. R. Shadish, T. D. Cook, & D. T. Campbell, 2002) is widely used in psychology and education, whereas Donald Rubin's causal model (P. W. Holland, 1986; D. B. Rubin, 1974, 2005) is widely used in economics, statistics, medicine, and public health. Campbell's approach focuses on…

  3. mediation: R Package for Causal Mediation Analysis

    Directory of Open Access Journals (Sweden)

    Dustin Tingley

    2014-09-01

    Full Text Available In this paper, we describe the R package mediation for conducting causal mediation analysis in applied empirical research. In many scientific disciplines, the goal of researchers is not only estimating causal effects of a treatment but also understanding the process in which the treatment causally affects the outcome. Causal mediation analysis is frequently used to assess potential causal mechanisms. The mediation package implements a comprehensive suite of statistical tools for conducting such an analysis. The package is organized into two distinct approaches. Using the model-based approach, researchers can estimate causal mediation effects and conduct sensitivity analysis under the standard research design. Furthermore, the design-based approach provides several analysis tools that are applicable under different experimental designs. This approach requires weaker assumptions than the model-based approach. We also implement a statistical method for dealing with multiple (causally dependent mediators, which are often encountered in practice. Finally, the package also offers a methodology for assessing causal mediation in the presence of treatment noncompliance, a common problem in randomized trials.

  4. Causal Mediation Analysis: Warning! Assumptions Ahead

    Science.gov (United States)

    Keele, Luke

    2015-01-01

    In policy evaluations, interest may focus on why a particular treatment works. One tool for understanding why treatments work is causal mediation analysis. In this essay, I focus on the assumptions needed to estimate mediation effects. I show that there is no "gold standard" method for the identification of causal mediation effects. In…

  5. A General Approach to Causal Mediation Analysis

    Science.gov (United States)

    Imai, Kosuke; Keele, Luke; Tingley, Dustin

    2010-01-01

    Traditionally in the social sciences, causal mediation analysis has been formulated, understood, and implemented within the framework of linear structural equation models. We argue and demonstrate that this is problematic for 3 reasons: the lack of a general definition of causal mediation effects independent of a particular statistical model, the…

  6. A Causal Model of Faculty Research Productivity.

    Science.gov (United States)

    Bean, John P.

    A causal model of faculty research productivity was developed through a survey of the literature. Models of organizational behavior, organizational effectiveness, and motivation were synthesized into a causal model of productivity. Two general types of variables were assumed to affect individual research productivity: institutional variables and…

  7. Counterfactual overdetermination vs. the causal exclusion problem.

    Science.gov (United States)

    Sparber, Georg

    2005-01-01

    This paper aims to show that a counterfactual approach to causation is not sufficient to provide a solution to the causal exclusion problem in the form of systematic overdetermination. Taking into account the truthmakers of causal counterfactuals provides a strong argument in favour of the identity of causes in situations of translevel, causation.

  8. Causal Indicators Can Help to Interpret Factors

    Science.gov (United States)

    Bentler, Peter M.

    2016-01-01

    The latent factor in a causal indicator model is no more than the latent factor of the factor part of the model. However, if the causal indicator variables are well-understood and help to improve the prediction of individuals' factor scores, they can help to interpret the meaning of the latent factor. Aguirre-Urreta, Rönkkö, and Marakas (2016)…

  9. Quasi-Experimental Designs for Causal Inference

    Science.gov (United States)

    Kim, Yongnam; Steiner, Peter

    2016-01-01

    When randomized experiments are infeasible, quasi-experimental designs can be exploited to evaluate causal treatment effects. The strongest quasi-experimental designs for causal inference are regression discontinuity designs, instrumental variable designs, matching and propensity score designs, and comparative interrupted time series designs. This…

  10. Determining Directional Dependency in Causal Associations

    Science.gov (United States)

    Pornprasertmanit, Sunthud; Little, Todd D.

    2012-01-01

    Directional dependency is a method to determine the likely causal direction of effect between two variables. This article aims to critique and improve upon the use of directional dependency as a technique to infer causal associations. We comment on several issues raised by von Eye and DeShon (2012), including: encouraging the use of the signs of…

  11. Ebola Virus and Marburg Virus

    Science.gov (United States)

    Ebola virus and Marburg virus Overview Ebola virus and Marburg virus are related viruses that cause hemorrhagic fevers — illnesses marked by severe bleeding (hemorrhage), organ failure and, in many ...

  12. Vidarabine, an Anti-Herpes Virus Agent, Protects Against the Development of Heart Failure With Relatively Mild Side-Effects on Cardiac Function in a Canine Model of Pacing-Induced Dilated Cardiomyopathy.

    Science.gov (United States)

    Nakamura, Takashi; Fujita, Takayuki; Kishimura, Megumi; Suita, Kenji; Hidaka, Yuko; Cai, Wenqian; Umemura, Masanari; Yokoyama, Utako; Uechi, Masami; Ishikawa, Yoshihiro

    2016-11-25

    In heart failure patients, chronic hyperactivation of sympathetic signaling is known to exacerbate cardiac dysfunction. In this study, the cardioprotective effect of vidarabine, an anti-herpes virus agent, which we identified as a cardiac adenylyl cyclase inhibitor, in dogs with pacing-induced dilated cardiomyopathy (DCM) was evaluated. In addition, the adverse effects of vidarabine on basal cardiac function was compared to those of the β-blocker, carvedilol.Methods and Results:Vidarabine and carvedilol attenuated the development of pacing-induced systolic dysfunction significantly and with equal effectiveness. Both agents also inhibited the development of cardiac apoptosis and fibrosis and reduced the Na + -Ca 2+ exchanger-1 protein level in the heart. Importantly, carvedilol significantly enlarged the left ventricle and atrium; vidarabine, in contrast, did not. Vidarabine-treated dogs maintained cardiac response to β-AR stimulation better than carvedilol-treated dogs did. Vidarabine may protect against pacing-induced DCM with less suppression of basal cardiac function than carvedilol in a dog model. (Circ J 2016; 80: 2496-2505).

  13. Heterogeneous Causal Effects and Sample Selection Bias

    DEFF Research Database (Denmark)

    Breen, Richard; Choi, Seongsoo; Holm, Anders

    2015-01-01

    The role of education in the process of socioeconomic attainment is a topic of long standing interest to sociologists and economists. Recently there has been growing interest not only in estimating the average causal effect of education on outcomes such as earnings, but also in estimating how...... causal effects might vary over individuals or groups. In this paper we point out one of the under-appreciated hazards of seeking to estimate heterogeneous causal effects: conventional selection bias (that is, selection on baseline differences) can easily be mistaken for heterogeneity of causal effects....... This might lead us to find heterogeneous effects when the true effect is homogenous, or to wrongly estimate not only the magnitude but also the sign of heterogeneous effects. We apply a test for the robustness of heterogeneous causal effects in the face of varying degrees and patterns of selection bias...

  14. Repair of Partly Misspecified Causal Diagrams.

    Science.gov (United States)

    Oates, Chris J; Kasza, Jessica; Simpson, Julie A; Forbes, Andrew B

    2017-07-01

    Errors in causal diagrams elicited from experts can lead to the omission of important confounding variables from adjustment sets and render causal inferences invalid. In this report, a novel method is presented that repairs a misspecified causal diagram through the addition of edges. These edges are determined using a data-driven approach designed to provide improved statistical efficiency relative to de novo structure learning methods. Our main assumption is that the expert is "directionally informed," meaning that "false" edges provided by the expert would not create cycles if added to the "true" causal diagram. The overall procedure is cast as a preprocessing technique that is agnostic to subsequent causal inferences. Results based on simulated data and data derived from an observational cohort illustrate the potential for data-assisted elicitation in epidemiologic applications. See video abstract at, http://links.lww.com/EDE/B208.

  15. Causality, spin, and equal-time commutators

    International Nuclear Information System (INIS)

    Abdel-Rahman, A.M.

    1975-01-01

    We study the causality constraints on the structure of the Lorentz-antisymmetric component of the commutator of two conserved isovector currents between fermion states of equal momenta. We discuss the sum rules that follow from causality and scaling, using the recently introduced refined infinite-momentum technique. The complete set of sum rules is found to include the spin-dependent fixed-mass sum rules obtained from light-cone commutators. The causality and scaling restrictions on the structure of the electromagnetic equal-time commutators are discussed, and it is found, in particular, that causality requires the spin-dependent part of the matrix element for the time-space electromagnetic equal-time commutator to vanish identically. It is also shown, in comparison with the electromagnetic case, that the corresponding matrix element for the time-space isovector current equal-time commutator is required, by causality, to have isospin-antisymmetric tensor and scalar operator Schwinger terms

  16. A Causal Model of Career Development and Quality of Life of College Students with Disabilities

    Science.gov (United States)

    Chun, Jina

    2017-01-01

    Researchers have assumed that social cognitive factors play significant roles in the career development of transition youth and young adults with disabilities and those without disabilities. However, research on the influence of the career decision-making process as a primary causal agent in one's psychosocial outcomes such as perceived level of…

  17. Natural co-infection of Solanum tuberosum crops by the Potato yellow vein virus and potyvirus in Colombia

    Directory of Open Access Journals (Sweden)

    Angela Villamil-Garzón

    2014-08-01

    Full Text Available The Potato yellow vein virus (PYVV, a Crinivirus with an RNA tripartite genome, is the causal agent of the potato yellow vein disease, reported in Colombian since 1950, with yield reductions of up to 50%. Co-infection of two or more viruses is common in nature and can be associated with differences in virus accumulation and symptom expression. No evidence of mixed infection between PYVV and other viruses has been reported. In this study, eight plants showing yellowing PYVV symptoms: four Solanum tuberosum Group Phureja (P and four Group Andigena (A, were collected in Cundinamarca, Colombia to detect mixed infection in the isolates using next generation sequencing (NGS. The Potato virus Y (PVY complete genome (similar to N strain and the Potato virus V (PVV partial genomes were detected using NGS and re-confirmed by RT-PCR. Preliminary field screening in a large sample showed that PYVV and PVY co-infect potato plants with a prevalence of 21% within the P group and 23% within the A group. This is the first report of co-infection of PYVV and potyvirus in Colombia and with the use of NGS. Considering that potyviruses enhance symptom severity and/or yield reductions in mixed infections, our results may be relevant for disease diagnosis, breeding programs and tuber certification.

  18. Summarizing Simulation Results using Causally-relevant States

    Science.gov (United States)

    Parikh, Nidhi; Marathe, Madhav; Swarup, Samarth

    2016-01-01

    As increasingly large-scale multiagent simulations are being implemented, new methods are becoming necessary to make sense of the results of these simulations. Even concisely summarizing the results of a given simulation run is a challenge. Here we pose this as the problem of simulation summarization: how to extract the causally-relevant descriptions of the trajectories of the agents in the simulation. We present a simple algorithm to compress agent trajectories through state space by identifying the state transitions which are relevant to determining the distribution of outcomes at the end of the simulation. We present a toy-example to illustrate the working of the algorithm, and then apply it to a complex simulation of a major disaster in an urban area. PMID:28042620

  19. Causal ubiquity in quantum physics a superluminal and local-causal physical ontology

    CERN Document Server

    Neelamkavil, Raphael

    2014-01-01

    A fixed highest criterial velocity (of light) in STR (special theory of relativity) is a convention for a layer of physical inquiry. QM (Quantum Mechanics) avoids action-at-a-distance using this concept, but accepts non-causality and action-at-a-distance in EPR (Einstein-Podolsky-Rosen-Paradox) entanglement experiments. Even in such allegedly non-causal processes, something exists processually in extension-motion, between the causal and the non-causal. If STR theoretically allows real-valued superluminal communication between EPR entangled particles, quantum processes become fully causal. That

  20. Causality violations in Lovelock theories

    Science.gov (United States)

    Brustein, Ram; Sherf, Yotam

    2018-04-01

    Higher-derivative gravity theories, such as Lovelock theories, generalize Einstein's general relativity (GR). Modifications to GR are expected when curvatures are near Planckian and appear in string theory or supergravity. But can such theories describe gravity on length scales much larger than the Planck cutoff length scale? Here we find causality constraints on Lovelock theories that arise from the requirement that the equations of motion (EOM) of perturbations be hyperbolic. We find a general expression for the "effective metric" in field space when Lovelock theories are perturbed around some symmetric background solution. In particular, we calculate explicitly the effective metric for a general Lovelock theory perturbed around cosmological Friedman-Robertson-Walker backgrounds and for some specific cases when perturbed around Schwarzschild-like solutions. For the EOM to be hyperbolic, the effective metric needs to be Lorentzian. We find that, unlike for GR, the effective metric is generically not Lorentzian when the Lovelock modifications are significant. So, we conclude that Lovelock theories can only be considered as perturbative extensions of GR and not as truly modified theories of gravity. We compare our results to those in the literature and find that they agree with and reproduce the results of previous studies.

  1. Cytomegalovirus and BK-Virus co-infection of a clinically non-functioning adrenal adenoma: innocent bystanders or new pathogenetic agents?

    Directory of Open Access Journals (Sweden)

    G Pomara

    2009-06-01

    Full Text Available We report a case of a 64-year-old woman who underwent left adrenalectomy with removal of a 8,5 cm clinically non-functioning adrenocortical adenoma and a 4-cm myelolipoma. Molecular testing for viral infection demonstrated the presence of cytomegalovirus (CMV DNA sequences in the adrenal adenoma, but not in the myelolipoma (confirmed by immunohistochemistry. Moreover, the adrenal adenoma was also positive for parvovirus B19, and both adrenal tumor samples were positive for polyomavirus BK (BKV and adenovirus DNA sequences. This is the first report of co-infection of an adrenocortical adenoma by CMV and BKV. The role of these viruses in adrenal tumorigenesis was postulated.

  2. A QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP AND MOLECULAR DOCKING STUDY ON A SERIES OF PYRIMIDINES ACTING AS ANTI-HEPATITIS C VIRUS AGENTS

    Directory of Open Access Journals (Sweden)

    Sakshi Gupta

    2013-12-01

    Full Text Available A QSAR and molecular modeling study was performed on a series of pyrimidines acting as hepatitis C virus inhibitors. In this case, anti-HCV potency of the compounds was found to be significantly correlated with the hydrophobic property of the molecule, Kier’s first-order valence molecular connectivity index for a particular substituent, total structure connectivity index of the molecule, and an indicator parameter used for the presence of benzothiazole ring. The validity of the correlation was judged by leave-one-out jackknife procedure and predicting the activity of some test compounds. Using the correlation obtained, some new compounds of high potency have been predicted in the series. A docking study using Molegro Virtual Docker was performed on these predicted compounds to decipher their interactions with the receptor. It was observed that all the predicted compounds had better interaction energy and docking score than the ligand complexed with the protein.

  3. A Multi-Agent Alphavirus DNA Vaccine Delivered by Intramuscular Electroporation Elicits Robust and Durable Virus Specific Immune Responses in Mice and Rabbits and Completely Protects Mice against Lethal Venezuelan, Western, and Eastern Equine Encephalitis Virus Aerosol Challenges

    Science.gov (United States)

    2016-07-26

    expression 128 of the structural proteins by adapting the gene sequence to reflect the codon bias of highly-129 expressed Homo sapiens genes...optimized expression in Homo sapiens followed by synthesis of the codon-167 optimized genes (Geneart). VEEV, WEEV, and EEEV DNA vaccine plasmids were...735 to biological warfare agents. Clin Lab Med 21:435-473. 736 9. Hanson RP, Sulkin SE, Beuscher EL , Hammon WM, McKinney RW, Work TH. 1967. Arbovirus

  4. Human murine mammary tumour virus-like agents are genetically distinct from endogenous retroviruses and are not detectable in breast cancer cell lines or biopsies

    International Nuclear Information System (INIS)

    Mant, Christine; Gillett, Cheryl; D'Arrigo, Corrado; Cason, John

    2004-01-01

    It has been reported that a human murine mammary tumour virus (MMTV)-like virus (HMLV), which may be an endogenous human retrovirus (HERV), occurs in the human breast cancer cell lines T47D and MCF-7 and, in 38% of human breast cancer biopsies. As the aetiology of most breast cancers remains unknown, it is important to verify these observations in differing breast cancer populations worldwide. Thus, we sought to determine the genetic relationships between HMLVs, MMTVs, and HERVs, and to investigate the association between HMLVs and breast cancer biopsies from South London, UK. Phylogenetic analyses of the env/pol region indicated that HMLVs are indistinct from MMTVs, and that MMTVS/HMLVs exhibit only low sequence homologies with HERVs. A search of the human genome confirmed that HMLVs are not endogenous. Using MMTV polymerase chain reaction (PCR) primers described previously, we amplified DNA from all cell lines except MCF-7 and from 7 of 44 (16%) breast cancer biopsies. A restriction fragment length polymorphism assay was designed to distinguish between HMLVs and MMTVs, and upon analyses, PCR amplicons appeared to be HMLVs. To confirm these findings, amplicons from the T47D cell line and from four randomly selected breast cancer patients were sequenced. Of 106 DNA sequences obtained, 103 were homologous with a short arm of human chromosome (Chr) 3 (3p13), two with Chr 4, and one with Chr 8. None of the sequences exhibited significant nucleotide homology with MMTVs, HMLVs, or with HERVs (all <50%). Thus, we conclude that (i) HMLVs are integral members of the MMTV family; (ii) MMTVs/HMLVs are genetically distinct from HERVs; (iii) MMTV/HMLV DNA is not present in human breast cancer cell lines or clinical biopsies in our locality

  5. 42 CFR 73.3 - HHS select agents and toxins.

    Science.gov (United States)

    2010-10-01

    ... been genetically modified. (d) HHS select agents or toxins that meet any of the following criteria are... Recombinant Organisms: (1) Nucleic acids that can produce infectious forms of any of the select agent viruses...

  6. (Highly pathogenic) Avian Influenza as a zoonotic agent

    OpenAIRE

    Kalthoff , Donata; Globig , Anja; Beer , Martin

    2010-01-01

    Summary Zoonotic agents challenging the world every year afresh are influenza A viruses. In the past, human pandemics caused by influenza A viruses had been occurring periodically. Wild aquatic birds are carriers of the full variety of influenza virus A subtypes, and thus, most probably constitute the natural reservoir of all influenza A viruses. Whereas avian influenza viruses in their natural avian reservoir are generally of low pathogenicity (LPAIV), some have gained virulence b...

  7. Causal localizations in relativistic quantum mechanics

    Science.gov (United States)

    Castrigiano, Domenico P. L.; Leiseifer, Andreas D.

    2015-07-01

    Causal localizations describe the position of quantum systems moving not faster than light. They are constructed for the systems with finite spinor dimension. At the center of interest are the massive relativistic systems. For every positive mass, there is the sequence of Dirac tensor-localizations, which provides a complete set of inequivalent irreducible causal localizations. They obey the principle of special relativity and are fully Poincaré covariant. The boosters are determined by the causal position operator and the other Poincaré generators. The localization with minimal spinor dimension is the Dirac localization. Thus, the Dirac equation is derived here as a mere consequence of the principle of causality. Moreover, the higher tensor-localizations, not known so far, follow from Dirac's localization by a simple construction. The probability of localization for positive energy states results to be described by causal positive operator valued (PO-) localizations, which are the traces of the causal localizations on the subspaces of positive energy. These causal Poincaré covariant PO-localizations for every irreducible massive relativistic system were, all the more, not known before. They are shown to be separated. Hence, the positive energy systems can be localized within every open region by a suitable preparation as accurately as desired. Finally, the attempt is made to provide an interpretation of the PO-localization operators within the frame of conventional quantum mechanics attributing an important role to the negative energy states.

  8. Causal inference, probability theory, and graphical insights.

    Science.gov (United States)

    Baker, Stuart G

    2013-11-10

    Causal inference from observational studies is a fundamental topic in biostatistics. The causal graph literature typically views probability theory as insufficient to express causal concepts in observational studies. In contrast, the view here is that probability theory is a desirable and sufficient basis for many topics in causal inference for the following two reasons. First, probability theory is generally more flexible than causal graphs: Besides explaining such causal graph topics as M-bias (adjusting for a collider) and bias amplification and attenuation (when adjusting for instrumental variable), probability theory is also the foundation of the paired availability design for historical controls, which does not fit into a causal graph framework. Second, probability theory is the basis for insightful graphical displays including the BK-Plot for understanding Simpson's paradox with a binary confounder, the BK2-Plot for understanding bias amplification and attenuation in the presence of an unobserved binary confounder, and the PAD-Plot for understanding the principal stratification component of the paired availability design. Published 2013. This article is a US Government work and is in the public domain in the USA.

  9. Can chance cause cancer? A causal consideration.

    Science.gov (United States)

    Stensrud, Mats Julius; Strohmaier, Susanne; Valberg, Morten; Aalen, Odd Olai

    2017-04-01

    The role of randomness, environment and genetics in cancer development is debated. We approach the discussion by using the potential outcomes framework for causal inference. By briefly considering the underlying assumptions, we suggest that the antagonising views arise due to estimation of substantially different causal effects. These effects may be hard to interpret, and the results cannot be immediately compared. Indeed, it is not clear whether it is possible to define a causal effect of chance at all. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Dual Causality and the Autonomy of Biology.

    Science.gov (United States)

    Bock, Walter J

    2017-03-01

    Ernst Mayr's concept of dual causality in biology with the two forms of causes (proximate and ultimate) continues to provide an essential foundation for the philosophy of biology. They are equivalent to functional (=proximate) and evolutionary (=ultimate) causes with both required for full biological explanations. The natural sciences can be classified into nomological, historical nomological and historical dual causality, the last including only biology. Because evolutionary causality is unique to biology and must be included for all complete biological explanations, biology is autonomous from the physical sciences.

  11. Mathematical implications of Einstein-Weyl causality

    International Nuclear Information System (INIS)

    Borchers, H.J.; Sen, R.N.

    2006-01-01

    The present work is the first systematic attempt at answering the following fundamental question: what mathematical structures does Einstein-Weyl causality impose on a point-set that has no other previous structure defined on it? The authors propose an axiomatization of Einstein-Weyl causality (inspired by physics), and investigate the topological and uniform structures that it implies. Their final result is that a causal space is densely embedded in one that is locally a differentiable manifold. The mathematical level required of the reader is that of the graduate student in mathematical physics. (orig.)

  12. The mistake of the causal relationship

    Directory of Open Access Journals (Sweden)

    О. Д. Комаров

    2015-03-01

    Full Text Available The article deals with issues of the mistake of the causal relationship. The modern criminal law science approaches to the content of the mistake of the causal relationship and its significance to the qualification of the crime are described. It is proved that in cases of dolus generalis different mental attitude of the guilty person to two separate acts of his conduct exist. Consequently, in mentioned above cases mistake of the causal relationship does not have place. The rules of qualification of the crimes commited with the mistake of causation and in cases of dolus generalis are proposed .

  13. Bayesian nonparametric generative models for causal inference with missing at random covariates.

    Science.gov (United States)

    Roy, Jason; Lum, Kirsten J; Zeldow, Bret; Dworkin, Jordan D; Re, Vincent Lo; Daniels, Michael J

    2018-03-26

    We propose a general Bayesian nonparametric (BNP) approach to causal inference in the point treatment setting. The joint distribution of the observed data (outcome, treatment, and confounders) is modeled using an enriched Dirichlet process. The combination of the observed data model and causal assumptions allows us to identify any type of causal effect-differences, ratios, or quantile effects, either marginally or for subpopulations of interest. The proposed BNP model is well-suited for causal inference problems, as it does not require parametric assumptions about the distribution of confounders and naturally leads to a computationally efficient Gibbs sampling algorithm. By flexibly modeling the joint distribution, we are also able to impute (via data augmentation) values for missing covariates within the algorithm under an assumption of ignorable missingness, obviating the need to create separate imputed data sets. This approach for imputing the missing covariates has the additional advantage of guaranteeing congeniality between the imputation model and the analysis model, and because we use a BNP approach, parametric models are avoided for imputation. The performance of the method is assessed using simulation studies. The method is applied to data from a cohort study of human immunodeficiency virus/hepatitis C virus co-infected patients. © 2018, The International Biometric Society.

  14. Synthesis, antiviral evaluation and molecular docking studies of N4-aryl substituted/unsubstituted thiosemicarbazones derived from 1-indanones as potent anti-bovine viral diarrhea virus agents.

    Science.gov (United States)

    Soraires Santacruz, María C; Fabiani, Matías; Castro, Eliana F; Cavallaro, Lucía V; Finkielsztein, Liliana M

    2017-08-01

    A series of N 4 -arylsubstituted thiosemicarbazones derived from 1-indanones and a set of compounds lacking such substitution in the N 4 position of the thiosemicarbazone moiety were synthesized and evaluated for their anti-bovine viral diarrhea virus (BVDV) activity. Among these, derivatives 2 and 15 displayed high activity (EC 50 =2.7±0.4 and 0.7±0.1µM, respectively) as inhibitors of BVDV replication. Novel key structural features related to the anti-BVDV activity were identified by structure-activity relationship (SAR) analysis. In a previous study, the thiosemicarbazone of 5,6-dimethoxy-1-indanone (5,6-TSC) was characterized as a non-nucleoside inhibitor (NNI) of the BVDV RNA-dependent RNA polymerase. In the present work, cross-resistance assays were performed with the most active compounds. Such studies were carried out on 5,6-TSC resistant BVDV (BVDV-TSC r T1) carrying mutations in the viral polymerase. This BVDV mutant was also resistant to compound 15. Molecular docking studies and MM/PBSA calculations were performed to assess the most active derivatives at the 5,6-TSC viral polymerase binding site. The differences in the interaction pattern and the binding affinity of derivative 15 either to the wild type or BVDV-TSC r T1 polymerase were key factors to define the mode of action of this compound. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Direct-acting antiviral agent efficacy and safety in renal transplant recipients with chronic hepatitis C virus infection: A PRISMA-compliant study.

    Science.gov (United States)

    Chen, Keliang; Lu, Pei; Song, Rijin; Zhang, Jiexiu; Tao, Rongzhen; Wang, Zijie; Zhang, Wei; Gu, Min

    2017-07-01

    The efficacy and safety of direct-acting antivirals (DAAs) for treating hepatitis C virus (HCV)-infected renal transplant recipients (RTRs) has not been determined. We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials and assessed the quality of eligible studies using the Joanna Briggs Institute scale. DAA efficacy and safety were assessed using standard mean difference (SMD) with 95% confidence intervals (95%CIs). Six studies (360 RTRs) were included. Two hundred thirty six RTRs (98.3%) achieved sustained virological response within 12 weeks; HCV infection was cleared in 239 RTRs after 24-week treatment. Liver function differed significantly pre- and posttreatment (alanine aminotransferase, SMD: 0.96, 95%CIs: 0.65, 1.26; aspartate aminotransferase, SMD: 0.89, 95%CIs: 0.60, 1.18); allograft function pre- and posttreatment was not statistically different (serum creatinine, SMD: -0.13, 95%CIs: -0.38, 0.12; estimated glomerular filtration rate, SMD: 0.20, 95%CIs: -0.11, 0.51). General symptoms (fatigue nausea dizziness or headache) were the most common adverse events (AEs) (39.3%). Severe AEs, that is, anemia, portal vein thrombosis, and streptococcus bacteraemia and pneumonia, were present in 1.1%, 0.6%, and 1.1% of RTRs, respectively. Our findings suggest that DAAs are highly efficacious and safe for treating HCV-infected RTRs and without significant AE.

  16. Assessing students' beliefs, emotions and causal attribution ...

    African Journals Online (AJOL)

    Keywords: academic emotion; belief; causal attribution; statistical validation; students' conceptions of learning ... Sadi & Lee, 2015), through their effect on motivation and learning strategies .... to understand why they may or may not be doing.

  17. Granger Causality Testing with Intensive Longitudinal Data.

    Science.gov (United States)

    Molenaar, Peter C M

    2018-06-01

    The availability of intensive longitudinal data obtained by means of ambulatory assessment opens up new prospects for prevention research in that it allows the derivation of subject-specific dynamic networks of interacting variables by means of vector autoregressive (VAR) modeling. The dynamic networks thus obtained can be subjected to Granger causality testing in order to identify causal relations among the observed time-dependent variables. VARs have two equivalent representations: standard and structural. Results obtained with Granger causality testing depend upon which representation is chosen, yet no criteria exist on which this important choice can be based. A new equivalent representation is introduced called hybrid VARs with which the best representation can be chosen in a data-driven way. Partial directed coherence, a frequency-domain statistic for Granger causality testing, is shown to perform optimally when based on hybrid VARs. An application to real data is provided.

  18. Causality Between Urban Concentration and Environmental Quality

    Directory of Open Access Journals (Sweden)

    Amin Pujiati

    2015-08-01

    Full Text Available Population is concentrated in urban areas can cause the external diseconomies on environment if it exceeds the carrying capacity of the space and the urban economy. Otherwise the quality of the environment is getting better, led to the concentration of population in urban areas are increasingly high. This study aims to analyze the relationship of causality between the urban concentration and environmental quality in urban agglomeration areas. The data used in the study of secondary data obtained from the Central Bureau of statistics and the City Government from 2000 to 2013. The analytical method used is the Granger causality and descriptive. Granger causality study results showed no pattern of reciprocal causality, between urban concentration and the quality of the environment, but there unidirectional relationship between the urban concentration and environmental quality. This means that increasing urban concentration led to decreased environmental quality.

  19. Selecting appropriate cases when tracing causal mechanisms

    DEFF Research Database (Denmark)

    Beach, Derek; Pedersen, Rasmus Brun

    2016-01-01

    The last decade has witnessed resurgence in the interest in studying the causal mechanisms linking causes and outcomes in the social sciences. This article explores the overlooked implications for case selection when tracing mechanisms using in-depth case studies. Our argument is that existing case...... selection guidelines are appropriate for research aimed at making cross-case claims about causal relationships, where case selection is primarily used to control for other causes. However, existing guidelines are not in alignment with case-based research that aims to trace mechanisms, where the goal...... is to unpack the causal mechanism between X and Y, enabling causal inferences to be made because empirical evidence is provided for how the mechanism actually operated in a particular case. The in-depth, within-case tracing of how mechanisms operate in particular cases produces what can be termed mechanistic...

  20. Rate-Agnostic (Causal) Structure Learning.

    Science.gov (United States)

    Plis, Sergey; Danks, David; Freeman, Cynthia; Calhoun, Vince

    2015-12-01

    Causal structure learning from time series data is a major scientific challenge. Extant algorithms assume that measurements occur sufficiently quickly; more precisely, they assume approximately equal system and measurement timescales. In many domains, however, measurements occur at a significantly slower rate than the underlying system changes, but the size of the timescale mismatch is often unknown. This paper develops three causal structure learning algorithms, each of which discovers all dynamic causal graphs that explain the observed measurement data, perhaps given undersampling. That is, these algorithms all learn causal structure in a "rate-agnostic" manner: they do not assume any particular relation between the measurement and system timescales. We apply these algorithms to data from simulations to gain insight into the challenge of undersampling.

  1. K-causality and degenerate spacetimes

    Science.gov (United States)

    Dowker, H. F.; Garcia, R. S.; Surya, S.

    2000-11-01

    The causal relation K+ was introduced by Sorkin and Woolgar to extend the standard causal analysis of C2 spacetimes to those that are only C0. Most of their results also hold true in the case of metrics with degeneracies which are C0 but vanish at isolated points. In this paper we seek to examine K+ explicitly in the case of topology-changing `Morse histories' which contain degeneracies. We first demonstrate some interesting features of this relation in globally Lorentzian spacetimes. In particular, we show that K+ is robust and the Hawking and Sachs characterization of causal continuity translates into a natural condition in terms of K+. We then examine K+ in topology-changing Morse spacetimes with the degenerate points excised and then for the Morse histories in which the degenerate points are reinstated. We find further characterizations of causal continuity in these cases.

  2. Manipulating Morality: Third-Party Intentions Alter Moral Judgments by Changing Causal Reasoning.

    Science.gov (United States)

    Phillips, Jonathan; Shaw, Alex

    2015-08-01

    The present studies investigate how the intentions of third parties influence judgments of moral responsibility for other agents who commit immoral acts. Using cases in which an agent acts under some situational constraint brought about by a third party, we ask whether the agent is blamed less for the immoral act when the third party intended for that act to occur. Study 1 demonstrates that third-party intentions do influence judgments of blame. Study 2 finds that third-party intentions only influence moral judgments when the agent's actions precisely match the third party's intention. Study 3 shows that this effect arises from changes in participants' causal perception that the third party was controlling the agent. Studies 4 and 5, respectively, show that the effect cannot be explained by changes in the distribution of blame or perceived differences in situational constraint faced by the agent. © 2014 Cognitive Science Society, Inc.

  3. Efficient nonparametric estimation of causal mediation effects

    OpenAIRE

    Chan, K. C. G.; Imai, K.; Yam, S. C. P.; Zhang, Z.

    2016-01-01

    An essential goal of program evaluation and scientific research is the investigation of causal mechanisms. Over the past several decades, causal mediation analysis has been used in medical and social sciences to decompose the treatment effect into the natural direct and indirect effects. However, all of the existing mediation analysis methods rely on parametric modeling assumptions in one way or another, typically requiring researchers to specify multiple regression models involving the treat...

  4. Inference of Boundaries in Causal Sets

    OpenAIRE

    Cunningham, William

    2017-01-01

    We investigate the extrinsic geometry of causal sets in $(1+1)$-dimensional Minkowski spacetime. The properties of boundaries in an embedding space can be used not only to measure observables, but also to supplement the discrete action in the partition function via discretized Gibbons-Hawking-York boundary terms. We define several ways to represent a causal set using overlapping subsets, which then allows us to distinguish between null and non-null bounding hypersurfaces in an embedding space...

  5. The Continuum Limit of Causal Fermion Systems

    OpenAIRE

    Finster, Felix

    2016-01-01

    This monograph introduces the basic concepts of the theory of causal fermion systems, a recent approach to the description of fundamental physics. The theory yields quantum mechanics, general relativity and quantum field theory as limiting cases and is therefore a candidate for a unified physical theory. From the mathematical perspective, causal fermion systems provide a general framework for describing and analyzing non-smooth geometries and "quantum geometries." The dynamics is described by...

  6. The Reactive-Causal Architecture: Introducing an Emotion Model along with Theories of Needs

    Science.gov (United States)

    Aydin, Ali Orhan; Orgun, Mehmet Ali

    In the entertainment application area, one of the major aims is to develop believable agents. To achieve this aim, agents should be highly autonomous, situated, flexible, and display affect. The Reactive-Causal Architecture (ReCau) is proposed to simulate these core attributes. In its current form, ReCau cannot explain the effects of emotions on intelligent behaviour. This study aims is to further improve the emotion model of ReCau to explain the effects of emotions on intelligent behaviour. This improvement allows ReCau to be emotional to support the development of believable agents.

  7. Causal strength induction from time series data.

    Science.gov (United States)

    Soo, Kevin W; Rottman, Benjamin M

    2018-04-01

    One challenge when inferring the strength of cause-effect relations from time series data is that the cause and/or effect can exhibit temporal trends. If temporal trends are not accounted for, a learner could infer that a causal relation exists when it does not, or even infer that there is a positive causal relation when the relation is negative, or vice versa. We propose that learners use a simple heuristic to control for temporal trends-that they focus not on the states of the cause and effect at a given instant, but on how the cause and effect change from one observation to the next, which we call transitions. Six experiments were conducted to understand how people infer causal strength from time series data. We found that participants indeed use transitions in addition to states, which helps them to reach more accurate causal judgments (Experiments 1A and 1B). Participants use transitions more when the stimuli are presented in a naturalistic visual format than a numerical format (Experiment 2), and the effect of transitions is not driven by primacy or recency effects (Experiment 3). Finally, we found that participants primarily use the direction in which variables change rather than the magnitude of the change for estimating causal strength (Experiments 4 and 5). Collectively, these studies provide evidence that people often use a simple yet effective heuristic for inferring causal strength from time series data. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  8. Kant on causal laws and powers.

    Science.gov (United States)

    Henschen, Tobias

    2014-12-01

    The aim of the paper is threefold. Its first aim is to defend Eric Watkins's claim that for Kant, a cause is not an event but a causal power: a power that is borne by a substance, and that, when active, brings about its effect, i.e. a change of the states of another substance, by generating a continuous flow of intermediate states of that substance. The second aim of the paper is to argue against Watkins that the Kantian concept of causal power is not the pre-critical concept of real ground but the category of causality, and that Kant holds with Hume that causal laws cannot be inferred non-inductively (that he accordingly has no intention to show in the Second analogy or elsewhere that events fall under causal laws). The third aim of the paper is to compare the Kantian position on causality with central tenets of contemporary powers ontology: it argues that unlike the variants endorsed by contemporary powers theorists, the Kantian variants of these tenets are resistant to objections that neo-Humeans raise to these tenets.

  9. Causality violation, gravitational shockwaves and UV completion

    Energy Technology Data Exchange (ETDEWEB)

    Hollowood, Timothy J.; Shore, Graham M. [Department of Physics, Swansea University,Swansea, SA2 8PP (United Kingdom)

    2016-03-18

    The effective actions describing the low-energy dynamics of QFTs involving gravity generically exhibit causality violations. These may take the form of superluminal propagation or Shapiro time advances and allow the construction of “time machines”, i.e. spacetimes admitting closed non-spacelike curves. Here, we discuss critically whether such causality violations may be used as a criterion to identify unphysical effective actions or whether, and how, causality problems may be resolved by embedding the action in a fundamental, UV complete QFT. We study in detail the case of photon scattering in an Aichelburg-Sexl gravitational shockwave background and calculate the phase shifts in QED for all energies, demonstrating their smooth interpolation from the causality-violating effective action values at low-energy to their manifestly causal high-energy limits. At low energies, these phase shifts may be interpreted as backwards-in-time coordinate jumps as the photon encounters the shock wavefront, and we illustrate how the resulting causality problems emerge and are resolved in a two-shockwave time machine scenario. The implications of our results for ultra-high (Planck) energy scattering, in which graviton exchange is modelled by the shockwave background, are highlighted.

  10. Domain-specific perceptual causality in children depends on the spatio-temporal configuration, not motion onset

    Directory of Open Access Journals (Sweden)

    Anne eSchlottmann

    2013-07-01

    Full Text Available Humans, even babies, perceive causality when one shape moves briefly and linearly after another. Motion timing is crucial in this and causal impressions disappear with short delays between motions. However, the role of temporal information is more complex: It is both a cue to causality and a factor that constrains processing. It affects ability to distinguish causality from non-causality, and social from mechanical causality. Here we study both issues with 3- to 7-year-olds and adults who saw two computer-animated squares and chose if a picture of mechanical, social or non-causality fit each event best. Prior work fit with the standard view that early in development, the distinction between the social and physical domains depends mainly on whether or not the agents make contact, and that this reflects concern with domain-specific motion onset, in particular, whether the motion is self-initiated or not. The present experiments challenge both parts of this position. In Experiments 1 and 2, we showed that not just spatial, but also animacy and temporal information affect how children distinguish between physical and social causality. In Experiments 3 and 4 we showed that children do not seem to use spatio-temporal information in perceptual causality to make inferences about self- or other-initiated motion onset. Overall, spatial contact may be developmentally primary in domain-specific perceptual causality in that it is processed easily and is dominant over competing cues, but it is not the only cue used early on and it is not used to infer motion onset. Instead, domain-specific causal impressions may be automatic reactions to specific perceptual configurations, with a complex role for temporal information.

  11. The Processing of Causal and Hierarchical Relations in Semantic Memory as Revealed by N400 and Frontal Negativity.

    Directory of Open Access Journals (Sweden)

    Xiuling Liang

    Full Text Available Most current studies investigating semantic memory have focused on associative (ring-emerald or taxonomic relations (bird-sparrow. Little is known about the question of how causal relations (virus-epidemic are stored and accessed in semantic memory. The goal of this study was to examine the processing of causally related, general associatively related and hierarchically related word pairs when participants were required to evaluate whether pairs of words were related in any way. The ERP data showed that the N400 amplitude (200-500 ms elicited by unrelated related words was more negative than all related words. Furthermore, the late frontal distributed negativity (500-700 ms elicited by causally related words was smaller than hierarchically related words, but not for general associated words. These results suggested the processing of causal relations and hierarchical relations in semantic memory recruited different degrees of cognitive resources, especially for role binding.

  12. Illness causal beliefs in Turkish immigrants

    Directory of Open Access Journals (Sweden)

    Klimidis Steven

    2007-07-01

    Full Text Available Abstract Background People hold a wide variety of beliefs concerning the causes of illness. Such beliefs vary across cultures and, among immigrants, may be influenced by many factors, including level of acculturation, gender, level of education, and experience of illness and treatment. This study examines illness causal beliefs in Turkish-immigrants in Australia. Methods Causal beliefs about somatic and mental illness were examined in a sample of 444 members of the Turkish population of Melbourne. The socio-demographic characteristics of the sample were broadly similar to those of the Melbourne Turkish community. Five issues were examined: the structure of causal beliefs; the relative frequency of natural, supernatural and metaphysical beliefs; ascription of somatic, mental, or both somatic and mental conditions to the various causes; the correlations of belief types with socio-demographic, modernizing and acculturation variables; and the relationship between causal beliefs and current illness. Results Principal components analysis revealed two broad factors, accounting for 58 percent of the variation in scores on illness belief scales, distinctly interpretable as natural and supernatural beliefs. Second, beliefs in natural causes were more frequent than beliefs in supernatural causes. Third, some causal beliefs were commonly linked to both somatic and mental conditions while others were regarded as more specific to either somatic or mental disorders. Last, there was a range of correlations between endorsement of belief types and factors defining heterogeneity within the community, including with demographic factors, indicators of modernizing and acculturative processes, and the current presence of illness. Conclusion Results supported the classification of causal beliefs proposed by Murdock, Wilson & Frederick, with a division into natural and supernatural causes. While belief in natural causes is more common, belief in supernatural causes

  13. Illness causal beliefs in Turkish immigrants.

    Science.gov (United States)

    Minas, Harry; Klimidis, Steven; Tuncer, Can

    2007-07-24

    People hold a wide variety of beliefs concerning the causes of illness. Such beliefs vary across cultures and, among immigrants, may be influenced by many factors, including level of acculturation, gender, level of education, and experience of illness and treatment. This study examines illness causal beliefs in Turkish-immigrants in Australia. Causal beliefs about somatic and mental illness were examined in a sample of 444 members of the Turkish population of Melbourne. The socio-demographic characteristics of the sample were broadly similar to those of the Melbourne Turkish community. Five issues were examined: the structure of causal beliefs; the relative frequency of natural, supernatural and metaphysical beliefs; ascription of somatic, mental, or both somatic and mental conditions to the various causes; the correlations of belief types with socio-demographic, modernizing and acculturation variables; and the relationship between causal beliefs and current illness. Principal components analysis revealed two broad factors, accounting for 58 percent of the variation in scores on illness belief scales, distinctly interpretable as natural and supernatural beliefs. Second, beliefs in natural causes were more frequent than beliefs in supernatural causes. Third, some causal beliefs were commonly linked to both somatic and mental conditions while others were regarded as more specific to either somatic or mental disorders. Last, there was a range of correlations between endorsement of belief types and factors defining heterogeneity within the community, including with demographic factors, indicators of modernizing and acculturative processes, and the current presence of illness. Results supported the classification of causal beliefs proposed by Murdock, Wilson & Frederick, with a division into natural and supernatural causes. While belief in natural causes is more common, belief in supernatural causes persists despite modernizing and acculturative influences. Different

  14. Localization and subcellular association of Grapevine Pinot Gris Virus in grapevine leaf tissues.

    Science.gov (United States)

    Tarquini, Giulia; Ermacora, Paolo; Bianchi, Gian Luca; De Amicis, Francesca; Pagliari, Laura; Martini, Marta; Loschi, Alberto; Saldarelli, Pasquale; Loi, Nazia; Musetti, Rita

    2018-05-01

    Despite the increasing impact of Grapevine Pinot gris disease (GPG-disease) worldwide, etiology about this disorder is still uncertain. The presence of the putative causal agent, the Grapevine Pinot Gris Virus (GPGV), has been reported in symptomatic grapevines (presenting stunting, chlorotic mottling, and leaf deformation) as well as in symptom-free plants. Moreover, information on virus localization in grapevine tissues and virus-plant interactions at the cytological level is missing at all. Ultrastructural and cytochemical investigations were undertaken to detect virus particles and the associated cytopathic effects in field-grown grapevine showing different symptom severity. Asymptomatic greenhouse-grown grapevines, which tested negative for GPGV by real time RT-PCR, were sampled as controls. Multiplex real-time RT-PCR and ELISA tests excluded the presence of viruses included in the Italian certification program both in field-grown and greenhouse-grown grapevines. Conversely, evidence was found for ubiquitous presence of Grapevine Rupestris Stem Pitting-associated Virus (GRSPaV), Hop Stunt Viroid (HSVd), and Grapevine Yellow Speckle Viroid 1 (GYSVd-1) in both plant groups. Moreover, in every field-grown grapevine, GPGV was detected by real-time RT-PCR. Ultrastructural observations and immunogold labelling assays showed filamentous flexuous viruses in the bundle sheath cells, often located inside membrane-bound organelles. No cytological differences were observed among field-grown grapevine samples showing different symptom severity. GPGV localization and associated ultrastructural modifications are reported and discussed, in the perspective of assisting management and control of the disease.

  15. El virus del papiloma humano (HPV, agente viral importante precusor de la mayoría de las displasias o cáncer cervical

    Directory of Open Access Journals (Sweden)

    Claudia Patricia Consuegra Mayor

    2004-01-01

    Full Text Available Una de las patologías más frecuentes con la que el hombre ha tenido que luchar en las últimas décadas es el cáncer. Los países industrializados y aun aquellos en vía de desarrollo se han dado a la tarea de combatir el cáncer, han hecho grandes esfuerzos e invertido cantidades de dinero con el propósito de conocer el origen y seguimiento de esta enfermedad y buscar alternativas que ayuden a erradicarla o a limitarla. Son impresionantes los datos recientes respecto al origen del cáncer a nivel molecular y se conocen con más precisión los procesos de progresión, invasión y metástasis tumoral (1. Todos estos experimentos han podido dilucidar algunos factores potenciadores o estimuladores para la aparición de esta enfermedad. El cáncer de cuello uterino es el segundo cáncer más común en la mujer después del cáncer de mama, y existe un desproporcionado aumento del cáncer cervical en mujeres jóvenes (2. Como el cáncer de cuello uterino se desarrolla en mujeres más jóvenes que el de mama, es una de las neoplasias malignas más devastadoras y es el principal cáncer genital femenino en los países en desarrollo (3,4. En Colombia es la segunda causa de mortalidad femenina (5. Desde hace más de 100 años se ha considerado que el cáncer cervical tiene una causa infecciosa (1. Posteriormente se demostró que los virus del papiloma humano (HPV, por su sigla en inglés human papillomavirus contribuyen directamente en la carcinogénesis. Es de anotar que el HPV es causa necesaria para el desarrollo del cáncer de cérvix, pero no es suficiente, ya que otros factores están involucrados en la progresión de infección a cáncer (6

  16. Predominance of hepatitis C virus Q80K among NS3 baseline-resistance-associated amino acid variants in direct-antiviral-agent-naïve patients with chronic hepatitis: single-centre experience.

    Science.gov (United States)

    Ruggiero, Tina; Proietti, Alex; Boglione, Lucio; Milia, Maria Grazia; Allice, Tiziano; Burdino, Elisa; Orofino, Giancarlo; Bonora, Stefano; Di Perri, Giovanni; Ghisetti, Valeria

    2015-11-01

    In the era of direct-acting antiviral agents (DAAs), hepatitis C virus (HCV) genotyping tests at baseline are controversial. The HCV NS3-Q80K polymorphism is associated with resistance to the recently approved NS3 inhibitor simeprevir (SMV) when combined with PEG-interferon and ribavirin (PEG-IFN/RBV) and alternative therapy should be considered for patients with baseline Q80K. The aim of this study was to provide an estimate of Q80K prevalence at baseline in a study group of 205 DAA-naïve patients (21% of them with HIV coinfection) using NS3 full-population direct sequencing to detect resistance-associated amino acid variants (RAVs). NS3 RAVs were identified in 56 patients (27.3%). Q80K was the most frequently reported one (41%), in both HIV/HCV-coinfected and HCV-monoinfected patients, but it was only detectable in cases of HCV-subtype 1a infection. Therefore, in clinical practice, an NS3-Q80K genotyping test prior to simeprevir plus PEG-IFN/RBV treatment is highly recommended.

  17. Developing a Novel Parameter Estimation Method for Agent-Based Model in Immune System Simulation under the Framework of History Matching: A Case Study on Influenza A Virus Infection

    Science.gov (United States)

    Li, Tingting; Cheng, Zhengguo; Zhang, Le

    2017-01-01

    Since they can provide a natural and flexible description of nonlinear dynamic behavior of complex system, Agent-based models (ABM) have been commonly used for immune system simulation. However, it is crucial for ABM to obtain an appropriate estimation for the key parameters of the model by incorporating experimental data. In this paper, a systematic procedure for immune system simulation by integrating the ABM and regression method under the framework of history matching is developed. A novel parameter estimation method by incorporating the experiment data for the simulator ABM during the procedure is proposed. First, we employ ABM as simulator to simulate the immune system. Then, the dimension-reduced type generalized additive model (GAM) is employed to train a statistical regression model by using the input and output data of ABM and play a role as an emulator during history matching. Next, we reduce the input space of parameters by introducing an implausible measure to discard the implausible input values. At last, the estimation of model parameters is obtained using the particle swarm optimization algorithm (PSO) by fitting the experiment data among the non-implausible input values. The real Influeza A Virus (IAV) data set is employed to demonstrate the performance of our proposed method, and the results show that the proposed method not only has good fitting and predicting accuracy, but it also owns favorable computational efficiency. PMID:29194393

  18. Developing a Novel Parameter Estimation Method for Agent-Based Model in Immune System Simulation under the Framework of History Matching: A Case Study on Influenza A Virus Infection

    Directory of Open Access Journals (Sweden)

    Tingting Li

    2017-12-01

    Full Text Available Since they can provide a natural and flexible description of nonlinear dynamic behavior of complex system, Agent-based models (ABM have been commonly used for immune system simulation. However, it is crucial for ABM to obtain an appropriate estimation for the key parameters of the model by incorporating experimental data. In this paper, a systematic procedure for immune system simulation by integrating the ABM and regression method under the framework of history matching is developed. A novel parameter estimation method by incorporating the experiment data for the simulator ABM during the procedure is proposed. First, we employ ABM as simulator to simulate the immune system. Then, the dimension-reduced type generalized additive model (GAM is employed to train a statistical regression model by using the input and output data of ABM and play a role as an emulator during history matching. Next, we reduce the input space of parameters by introducing an implausible measure to discard the implausible input values. At last, the estimation of model parameters is obtained using the particle swarm optimization algorithm (PSO by fitting the experiment data among the non-implausible input values. The real Influeza A Virus (IAV data set is employed to demonstrate the performance of our proposed method, and the results show that the proposed method not only has good fitting and predicting accuracy, but it also owns favorable computational efficiency.

  19. 9 CFR 121.3 - VS select agents and toxins.

    Science.gov (United States)

    2010-01-01

    ... genetically modified. (d) VS select agents or toxins that meet any of the following criteria are excluded from... AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS POSSESSION, USE, AND... recombinant organisms: (1) Nucleic acids that can produce infectious forms of any of the select agent viruses...

  20. [Alkylating agents].

    Science.gov (United States)

    Pourquier, Philippe

    2011-11-01

    With the approval of mechlorethamine by the FDA in 1949 for the treatment of hematologic malignancies, alkylating agents are the oldest class of anticancer agents. Even though their clinical use is far beyond the use of new targeted therapies, they still occupy a major place in specific indications and sometimes represent the unique option for the treatment of refractory diseases. Here, we are reviewing the major classes of alkylating agents and their mechanism of action, with a particular emphasis for the new generations of alkylating agents. As for most of the chemotherapeutic agents used in the clinic, these compounds are derived from natural sources. With a complex but original mechanism of action, they represent new interesting alternatives for the clinicians, especially for tumors that are resistant to conventional DNA damaging agents. We also briefly describe the different strategies that have been or are currently developed to potentiate the use of classical alkylating agents, especially the inhibition of pathways that are involved in the repair of DNA lesions induced by these agents. In this line, the development of PARP inhibitors is a striking example of the recent regain of interest towards the "old" alkylating agents.

  1. Entanglement entropy in causal set theory

    Science.gov (United States)

    Sorkin, Rafael D.; Yazdi, Yasaman K.

    2018-04-01

    Entanglement entropy is now widely accepted as having deep connections with quantum gravity. It is therefore desirable to understand it in the context of causal sets, especially since they provide in a natural manner the UV cutoff needed to render entanglement entropy finite. Formulating a notion of entanglement entropy in a causal set is not straightforward because the type of canonical hypersurface-data on which its definition typically relies is not available. Instead, we appeal to the more global expression given in Sorkin (2012 (arXiv:1205.2953)) which, for a Gaussian scalar field, expresses the entropy of a spacetime region in terms of the field’s correlation function within that region (its ‘Wightman function’ W(x, x') ). Carrying this formula over to the causal set, one obtains an entropy which is both finite and of a Lorentz invariant nature. We evaluate this global entropy-expression numerically for certain regions (primarily order-intervals or ‘causal diamonds’) within causal sets of 1  +  1 dimensions. For the causal-set counterpart of the entanglement entropy, we obtain, in the first instance, a result that follows a (spacetime) volume law instead of the expected (spatial) area law. We find, however, that one obtains an area law if one truncates the commutator function (‘Pauli–Jordan operator’) and the Wightman function by projecting out the eigenmodes of the Pauli–Jordan operator whose eigenvalues are too close to zero according to a geometrical criterion which we describe more fully below. In connection with these results and the questions they raise, we also study the ‘entropy of coarse-graining’ generated by thinning out the causal set, and we compare it with what one obtains by similarly thinning out a chain of harmonic oscillators, finding the same, ‘universal’ behaviour in both cases.

  2. Plants as sources of antiviral agents | Abonyi | African Journal of ...

    African Journals Online (AJOL)

    Antivirals are substances other than a virus or virus containing vaccine or specific antibody which can produce either a protective or therapeutic effect to the clear detectable advantage of the virus infected host. The search for antiviral agents began in earnest in the 1950s but this was directed mainly by chance, with little or ...

  3. Aspectos moleculares del virus de la parvovirosis canina y sus implicaciones en la enfermedad

    Directory of Open Access Journals (Sweden)

    César A. Díaz R.

    2008-06-01

    Full Text Available El parvovirus canino tipo 2 (CPV-2 es el agente causal de una enfermedad infecto-contagiosa que produce una gastroenteritis aguda hemorrágica que afecta a caninos jóvenes. El CPV-2 se adaptó a la especie canina por mutación del virus de la Panleucopenia felina (FPV luego de su paso por animales silvestres como el hurón y los zorros. La alta variabilidad de la proteína viral 2 (VP2 es la causa principal del amplio rango de hospedadores y de las reacciones cruzadas entre las variantes. En la actualidad, la secuenciación de esta proteína ha permitido identificar tres variantes del virus conocidas como 2a, 2b y 2c que conviven en el mundo con diferencias en tropismo celular, infecciocidad y patogenicidad. El virus ssADN ha presentado una gran variación génica en cortos períodos de tiempo lo que indica un alto grado de selección por evolución sólo comparable con virus RN, esta alta variabilidad no se ha aclarado totalmente. El empleo de las técnicas moleculares permitirá diferenciar entre cepas vacunales y de campo, tanto como contar con técnicas diagnósticas confiables y específicas.

  4. Coat protein sequence shows that Cucumber mosaic virus isolate

    Indian Academy of Sciences (India)

    A viral disease was identified on geraniums (Pelargonium spp.) grown in a greenhouse at the Institute of Himalayan Bioresource Technology (IHBT), Palampur, exhibiting mild mottling and stunting. The causal virus (Cucumber mosaic virus, CMV) was identified and characterized on the basis of host range, aphid ...

  5. The Relevance of Causal Social Construction

    Directory of Open Access Journals (Sweden)

    Marques Teresa

    2017-02-01

    Full Text Available Social constructionist claims are surprising and interesting when they entail that presumably natural kinds are in fact socially constructed. The claims are interesting because of their theoretical and political importance. Authors like Díaz-León argue that constitutive social construction is more relevant for achieving social justice than causal social construction. This paper challenges this claim. Assuming there are socially salient groups that are discriminated against, the paper presents a dilemma: if there were no constitutively constructed social kinds, the causes of the discrimination of existing social groups would have to be addressed, and understanding causal social construction would be relevant to achieve social justice. On the other hand, not all possible constitutively socially constructed kinds are actual social kinds. If an existing social group is constitutively constructed as a social kind K, the fact that it actually exists as a K has social causes. Again, causal social construction is relevant. The paper argues that (i for any actual social kind X, if X is constitutively socially constructed as K, then it is also causally socially constructed; and (ii causal social construction is at least as relevant as constitutive social construction for concerns of social justice. For illustration, I draw upon two phenomena that are presumed to contribute towards the discrimination of women: (i the poor performance effects of stereotype threat, and (ii the silencing effects of gendered language use.

  6. Preschoolers prefer to learn causal information

    Directory of Open Access Journals (Sweden)

    Aubry eAlvarez

    2015-02-01

    Full Text Available Young children, in general, appear to have a strong drive to explore the environment in ways that reveal its underlying causal structure. But are they really attuned specifically to casual information in this quest for understanding, or do they show equal interest in other types of non-obvious information about the world? To answer this question, we introduced 20 three-year-old children to two puppets who were anxious to tell the child about a set of novel artifacts and animals. One puppet consistently described causal properties of the items while the other puppet consistently described carefully matched non-causal properties of the same items. After a familiarization period in which children learned which type of information to expect from each informant, children were given the opportunity to choose which they wanted to hear describe each of eight pictured test items. On average, children chose to hear from the informant that provided causal descriptions on 72% of the trials. This preference for causal information has important implications for explaining the role of conceptual information in supporting early learning and may suggest means for maximizing interest and motivation in young children.

  7. Gravity and matter in causal set theory

    International Nuclear Information System (INIS)

    Sverdlov, Roman; Bombelli, Luca

    2009-01-01

    The goal of this paper is to propose an approach to the formulation of dynamics for causal sets and coupled matter fields. We start from the continuum version of the action for a Klein-Gordon field coupled to gravity, and rewrite it first using quantities that have a direct correspondent in the case of a causal set, namely volumes, causal relations and timelike lengths, as variables to describe the geometry. In this step, the local Lagrangian density L(f;x) for a set of fields f is recast into a quasilocal expression L 0 (f;p,q) that depends on pairs of causally related points pprq and is a function of the values of f in the Alexandrov set defined by those points, and whose limit as p and q approach a common point x is L(f;x). We then describe how to discretize L 0 (f;p,q) and use it to define a causal-set-based action.

  8. A frequency domain subspace algorithm for mixed causal, anti-causal LTI systems

    NARCIS (Netherlands)

    Fraanje, Rufus; Verhaegen, Michel; Verdult, Vincent; Pintelon, Rik

    2003-01-01

    The paper extends the subspacc identification method to estimate state-space models from frequency response function (FRF) samples, proposed by McKelvey et al. (1996) for mixed causal/anti-causal systems, and shows that other frequency domain subspace algorithms can be extended similarly. The method

  9. Causal inheritance in plane wave quotients

    International Nuclear Information System (INIS)

    Hubeny, Veronika E.; Rangamani, Mukund; Ross, Simon F.

    2003-01-01

    We investigate the appearance of closed timelike curves in quotients of plane waves along spacelike isometries. First we formulate a necessary and sufficient condition for a quotient of a general spacetime to preserve stable causality. We explicitly show that the plane waves are stably causal; in passing, we observe that some pp-waves are not even distinguishing. We then consider the classification of all quotients of the maximally supersymmetric ten-dimensional plane wave under a spacelike isometry, and show that the quotient will lead to closed timelike curves iff the isometry involves a translation along the u direction. The appearance of these closed timelike curves is thus connected to the special properties of the light cones in plane wave spacetimes. We show that all other quotients preserve stable causality

  10. Inference of boundaries in causal sets

    Science.gov (United States)

    Cunningham, William J.

    2018-05-01

    We investigate the extrinsic geometry of causal sets in (1+1) -dimensional Minkowski spacetime. The properties of boundaries in an embedding space can be used not only to measure observables, but also to supplement the discrete action in the partition function via discretized Gibbons–Hawking–York boundary terms. We define several ways to represent a causal set using overlapping subsets, which then allows us to distinguish between null and non-null bounding hypersurfaces in an embedding space. We discuss algorithms to differentiate between different types of regions, consider when these distinctions are possible, and then apply the algorithms to several spacetime regions. Numerical results indicate the volumes of timelike boundaries can be measured to within 0.5% accuracy for flat boundaries and within 10% accuracy for highly curved boundaries for medium-sized causal sets with N  =  214 spacetime elements.

  11. Normalizing the causality between time series

    Science.gov (United States)

    Liang, X. San

    2015-08-01

    Recently, a rigorous yet concise formula was derived to evaluate information flow, and hence the causality in a quantitative sense, between time series. To assess the importance of a resulting causality, it needs to be normalized. The normalization is achieved through distinguishing a Lyapunov exponent-like, one-dimensional phase-space stretching rate and a noise-to-signal ratio from the rate of information flow in the balance of the marginal entropy evolution of the flow recipient. It is verified with autoregressive models and applied to a real financial analysis problem. An unusually strong one-way causality is identified from IBM (International Business Machines Corporation) to GE (General Electric Company) in their early era, revealing to us an old story, which has almost faded into oblivion, about "Seven Dwarfs" competing with a giant for the mainframe computer market.

  12. Spatial hypersurfaces in causal set cosmology

    International Nuclear Information System (INIS)

    Major, Seth A; Rideout, David; Surya, Sumati

    2006-01-01

    Within the causal set approach to quantum gravity, a discrete analogue of a spacelike region is a set of unrelated elements, or an antichain. In the continuum approximation of the theory, a moment-of-time hypersurface is well represented by an inextendible antichain. We construct a richer structure corresponding to a thickening of this antichain containing non-trivial geometric and topological information. We find that covariant observables can be associated with such thickened antichains and transitions between them, in classical sequential growth models of causal sets. This construction highlights the difference between the covariant measure on causal set cosmology and the standard sum-over-histories approach: the measure is assigned to completed histories rather than to histories on a restricted spacetime region. The resulting re-phrasing of the sum-over-histories may be fruitful in other approaches to quantum gravity

  13. Testing the causal theory of reference.

    Science.gov (United States)

    Domaneschi, Filippo; Vignolo, Massimiliano; Di Paola, Simona

    2017-04-01

    Theories of reference are a crucial research topic in analytic philosophy. Since the publication of Kripke's Naming and Necessity, most philosophers have endorsed the causal/historical theory of reference. The goal of this paper is twofold: (i) to discuss a method for testing experimentally the causal theory of reference for proper names by investigating linguistic usage and (ii) to present the results from two experiments conducted with that method. Data collected in our experiments confirm the causal theory of reference for people proper names and for geographical proper names. A secondary but interesting result is that the semantic domain affects reference assignment: while with people proper names speakers tend to assign the semantic reference, with geographical proper names they are prompted to assign the speaker's reference. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Bulk viscous cosmology with causal transport theory

    International Nuclear Information System (INIS)

    Piattella, Oliver F.; Fabris, Júlio C.; Zimdahl, Winfried

    2011-01-01

    We consider cosmological scenarios originating from a single imperfect fluid with bulk viscosity and apply Eckart's and both the full and the truncated Müller-Israel-Stewart's theories as descriptions of the non-equilibrium processes. Our principal objective is to investigate if the dynamical properties of Dark Matter and Dark Energy can be described by a single viscous fluid and how such description changes when a causal theory (Müller-Israel-Stewart's, both in its full and truncated forms) is taken into account instead of Eckart's non-causal one. To this purpose, we find numerical solutions for the gravitational potential and compare its behaviour with the corresponding ΛCDM case. Eckart's and the full causal theory seem to be disfavoured, whereas the truncated theory leads to results similar to those of the ΛCDM model for a bulk viscous speed in the interval 10 −11 || cb 2 ∼ −8

  15. Causal inheritance in plane wave quotients

    Science.gov (United States)

    Hubeny, Veronika E.; Rangamani, Mukund; Ross, Simon F.

    2004-01-01

    We investigate the appearance of closed timelike curves in quotients of plane waves along spacelike isometries. First we formulate a necessary and sufficient condition for a quotient of a general space-time to preserve stable causality. We explicitly show that the plane waves are stably causal; in passing, we observe that some pp waves are not even distinguishing. We then consider the classification of all quotients of the maximally supersymmetric ten-dimensional plane wave under a spacelike isometry, and show that the quotient will lead to closed timelike curves iff the isometry involves a translation along the u direction. The appearance of these closed timelike curves is thus connected to the special properties of the light cones in plane wave space-times. We show that all other quotients preserve stable causality.

  16. Characteristics of Filoviridae: Marburg and Ebola Viruses

    Science.gov (United States)

    Beer, Brigitte; Kurth, Reinhard; Bukreyev, Alexander

    Filoviruses are enveloped, nonsegmented negative-stranded RNA viruses. The two species, Marburg and Ebola virus, are serologically, biochemically, and genetically distinct. Marburg virus was first isolated during an outbreak in Europe in 1967, and Ebola virus emerged in 1976 as the causative agent of two simultaneous outbreaks in southern Sudan and northern Zaire. Although the main route of infection is known to be person-to-person transmission by intimate contact, the natural reservoir for filoviruses still remains a mystery.

  17. Neural correlates of continuous causal word generation.

    Science.gov (United States)

    Wende, Kim C; Straube, Benjamin; Stratmann, Mirjam; Sommer, Jens; Kircher, Tilo; Nagels, Arne

    2012-09-01

    Causality provides a natural structure for organizing our experience and language. Causal reasoning during speech production is a distinct aspect of verbal communication, whose related brain processes are yet unknown. The aim of the current study was to investigate the neural mechanisms underlying the continuous generation of cause-and-effect coherences during overt word production. During fMRI data acquisition participants performed three verbal fluency tasks on identical cue words: A novel causal verbal fluency task (CVF), requiring the production of multiple reasons to a given cue word (e.g. reasons for heat are fire, sun etc.), a semantic (free association, FA, e.g. associations with heat are sweat, shower etc.) and a phonological control task (phonological verbal fluency, PVF, e.g. rhymes with heat are meat, wheat etc.). We found that, in contrast to PVF, both CVF and FA activated a left lateralized network encompassing inferior frontal, inferior parietal and angular regions, with further bilateral activation in middle and inferior as well as superior temporal gyri and the cerebellum. For CVF contrasted against FA, we found greater bold responses only in the left middle frontal cortex. Large overlaps in the neural activations during free association and causal verbal fluency indicate that the access to causal relationships between verbal concepts is at least partly based on the semantic neural network. The selective activation in the left middle frontal cortex for causal verbal fluency suggests that distinct neural processes related to cause-and-effect-relations are associated with the recruitment of middle frontal brain areas. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. BOLD Granger causality reflects vascular anatomy.

    Directory of Open Access Journals (Sweden)

    J Taylor Webb

    Full Text Available A number of studies have tried to exploit subtle phase differences in BOLD time series to resolve the order of sequential activation of brain regions, or more generally the ability of signal in one region to predict subsequent signal in another region. More recently, such lag-based measures have been applied to investigate directed functional connectivity, although this application has been controversial. We attempted to use large publicly available datasets (FCON 1000, ADHD 200, Human Connectome Project to determine whether consistent spatial patterns of Granger Causality are observed in typical fMRI data. For BOLD datasets from 1,240 typically developing subjects ages 7-40, we measured Granger causality between time series for every pair of 7,266 spherical ROIs covering the gray matter and 264 seed ROIs at hubs of the brain's functional network architecture. Granger causality estimates were strongly reproducible for connections in a test and replication sample (n=620 subjects for each group, as well as in data from a single subject scanned repeatedly, both during resting and passive video viewing. The same effect was even stronger in high temporal resolution fMRI data from the Human Connectome Project, and was observed independently in data collected during performance of 7 task paradigms. The spatial distribution of Granger causality reflected vascular anatomy with a progression from Granger causality sources, in Circle of Willis arterial inflow distributions, to sinks, near large venous vascular structures such as dural venous sinuses and at the periphery of the brain. Attempts to resolve BOLD phase differences with Granger causality should consider the possibility of reproducible vascular confounds, a problem that is independent of the known regional variability of the hemodynamic response.

  19. Prevalence of hepatitis C virus-resistant association substitutions to direct-acting antiviral agents in treatment-naïve hepatitis C genotype 1b-infected patients in western China

    Directory of Open Access Journals (Sweden)

    Li Z

    2017-10-01

    Full Text Available Zhao Li,* Zhi-wei Chen,* Hu Li, Hong Ren, Peng Hu Department of Infectious Diseases, Institute for Viral Hepatitis, Key Laboratory of Molecular Biology for Infectious Diseases, Chinese Ministry of Education, Second Affiliated Hospital of Chongqing Medical University, Chongqing, China *These authors contributed equally to this work. Background: Direct-acting antivirals (DAAs against hepatitis C virus (HCV are potent and highly efficacious. However, resistance-associated substitutions (RASs relevant to DAAs can impair treatment effectiveness even at baseline. Moreover, the prevalence of baseline RASs in HCV genotype 1b-infected patients in western China is still unclear. Materials and methods: Direct sequencing of the HCV NS3, NS5A, and NS5B regions was performed in baseline serum samples of 70 DAAs treatment-naïve HCV 1b-infected patients in western China. The sequences were analyzed with MEGA version 5.05 software. Evolutionary patterns of RASs and amino-acid covariance patterns in the NS3, NS5A, and NS5B genes were analyzed by MEGA and Cytoscape (version 3.2.1, respectively.Results: The presence of at least one RAS in the NS3 region (C16S, T54S, Q80R/L, A87T, R117H, S122G, V132I, V170I was observed in 85.48% (53 of 62 of patients, RASs in the NS5A region (L28M, R30Q, Q54H, P58S/T, Q62H/R, Y93H were observed in 42.42% (28 of 66 of patients, and RASs in the NS5B region (N142S, A300T, C316N, A338V, S365A, L392I, M414L, I424V, A442T, V499A, S556G were observed in 100% (44 of 44 of patients. Evolutionary patterns of RASs and amino-acid covariance patterns for the NS3, NS5A, and NS5B genes are reported.Conclusion: The prevalence of RASs relevant to DAAs detected in the NS3, NS5A, and NS5B regions of HCV 1b from DAA treatment-naïve patients is high. Therefore, more attention should be paid to RASs associated with DAAs in the upcoming DAA-treatment era in China. Keywords: hepatitis C virus, unstructured proteins, resistance

  20. Causal interpretation of stochastic differential equations

    DEFF Research Database (Denmark)

    Sokol, Alexander; Hansen, Niels Richard

    2014-01-01

    We give a causal interpretation of stochastic differential equations (SDEs) by defining the postintervention SDE resulting from an intervention in an SDE. We show that under Lipschitz conditions, the solution to the postintervention SDE is equal to a uniform limit in probability of postintervention...... structural equation models based on the Euler scheme of the original SDE, thus relating our definition to mainstream causal concepts. We prove that when the driving noise in the SDE is a Lévy process, the postintervention distribution is identifiable from the generator of the SDE....

  1. Morse theory on timelike and causal curves

    International Nuclear Information System (INIS)

    Everson, J.; Talbot, C.J.

    1976-01-01

    It is shown that the set of timelike curves in a globally hyperbolic space-time manifold can be given the structure of a Hilbert manifold under a suitable definition of 'timelike.' The causal curves are the topological closure of this manifold. The Lorentzian energy (corresponding to Milnor's energy, except that the Lorentzian inner product is used) is shown to be a Morse function for the space of causal curves. A fixed end point index theorem is obtained in which a lower bound for the index of the Hessian of the Lorentzian energy is given in terms of the sum of the orders of the conjugate points between the end points. (author)

  2. Inferring causality from noisy time series data

    DEFF Research Database (Denmark)

    Mønster, Dan; Fusaroli, Riccardo; Tylén, Kristian

    2016-01-01

    Convergent Cross-Mapping (CCM) has shown high potential to perform causal inference in the absence of models. We assess the strengths and weaknesses of the method by varying coupling strength and noise levels in coupled logistic maps. We find that CCM fails to infer accurate coupling strength...... and even causality direction in synchronized time-series and in the presence of intermediate coupling. We find that the presence of noise deterministically reduces the level of cross-mapping fidelity, while the convergence rate exhibits higher levels of robustness. Finally, we propose that controlled noise...

  3. Vaccines to Prevent Cancers Not Caused by Viruses - Annual Plan

    Science.gov (United States)

    We have vaccines against viruses that cause cancer, but what about vaccines for cancers not caused by viruses? Learn about NCI's development of safe and effective vaccines for cancers not caused by infectious agents.

  4. viruses associated with human and animal influenza - a review 40

    African Journals Online (AJOL)

    DR. AMINU

    These include Influenza A,B and C. Influenza viruses are members of the family. Orthomyxoviridae. .... low pathogenicity avian influenza may be as mild as ruffled feathers, a ... influenza A viruses are zoonotic agents recognized as continuing ...

  5. Chemical Agents

    Science.gov (United States)

    ... CR) see Riot Control Agents Digitalis Distilled mustard (HD) see Sulfur mustard E Ethylene glycol F Fentanyls and other opioids H Hydrazine Hydrofluoric acid (hydrogen fluoride) Hydrogen chloride Hydrogen cyanide (AC) Hydrogen ...

  6. Influenza virus inactivated by artificial ribonucleases as a prospective killed virus vaccine.

    Science.gov (United States)

    Fedorova, Antonina A; Goncharova, Elena P; Kovpak, Mikhail P; Vlassov, Valentin V; Zenkova, Marina A

    2012-04-19

    The inactivation of viral particles with agents causing minimal damage to the structure of surface epitopes is a well-established approach for the production of killed virus vaccines. Here, we describe new agents for the inactivation of influenza virus, artificial ribonucleases (aRNases), which are chemical compounds capable of cleaving RNA molecules. Several aRNases were identified, exhibiting significant virucidal activity against the influenza A virus and causing a minimal effect on the affinity of monoclonal antibodies for the inactivated virus. Using a murine model of the influenza virus infection, a high protective activity of the aRNase-inactivated virus as a vaccine was demonstrated. The results of the experiments demonstrate the efficacy of novel chemical agents in the preparation of vaccines against influenza and, perhaps, against other infections caused by RNA viruses. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Apolipoprotein B-associated cholesterol is a determinant of treatment outcome in patients with chronic hepatitis C virus infection receiving anti-viral agents interferon-alpha and ribavirin.

    Science.gov (United States)

    Sheridan, D A; Price, D A; Schmid, M L; Toms, G L; Donaldson, P; Neely, D; Bassendine, M F

    2009-06-15

    Hepatitis C virus (HCV) co-opts very-low-density lipoprotein (VLDL) pathways for replication, secretion and entry into hepatocytes and associates with apolipoprotein B (apoB) in plasma. Each VLDL contains apoB-100 and variable amounts of apolipoproteins E and C, cholesterol and triglycerides. To determine whether baseline lipid levels predicted treatment outcome. Retrospective analysis was performed of 250 chronic hepatitis C (CHC) patients who had received anti-viral agents interferon-alpha and ribavirin; 165 had a sustained virological response (SVR). Pre- and post-treatment nonfasting lipid profiles were measured and non-high-density lipoprotein (non-HDL) cholesterol (i.e. apoB-associated) was calculated. Binary logistic regression analysis assessed factors independently associated with treatment outcome. There was an independent association between higher apoB-associated cholesterol (non-HDL-C) and increased odds of SVR (odds ratio 2.09, P = 0.042). In multivariate analysis, non-HDL-C was significantly lower in HCV genotype 3 (g3) than genotype 1 (P = 0.007); this was reversible upon eradication of HCVg3 (pre-treatment non-HDL-C = 2.8 mmol/L, SVR = 3.6 mmol/L, P < 0.001). Higher apoB-associated cholesterol is positively associated with treatment outcome in CHC patients receiving anti-viral therapy, possibly due to competition between apoB-containing lipoproteins and infectious low-density HCV lipo-viral particles for hepatocyte entry via shared lipoprotein receptors.

  8. Uso recomendado de antirretrovíricos en embarazadas infectadas por el VIH-1 para reducir la transmisión perinatal del virus Recommendations on the use of antiretroviral agents in pregnant women infected with HIV-1

    Directory of Open Access Journals (Sweden)

    2001-05-01

    Full Text Available In February 1994, a clinical trial by the Pediatrics AIDS Clinical Trials Group (PACTG 076 demonstrated, for the first time, that it was possible to reduce the risk of vertical transmission of human immunodeficiency virus type 1 (HIV-1 by nearly 70% by means of a triple therapeutic regimen: 1 oral zidovudine (ZDV beginning anytime between the 14th and 34th week of gestation until the end of pregnancy; 2 intravenous ZDV during pregnancy, and 3 administration of oral ZDV to neonates during the first 6 weeks of life. Later, epidemiologic studies performed in the United States of America and France showed that this regimen drastically reduced perinatal transmission in clinical practice. Since then, important strides have been made, not only in terms of treatment (new drugs and highly effective therapeutic regimens and diagnosis (tests that can measure the viral load, but also in terms of an increased understanding of the pathogenesis of perinatal transmission of HIV-1. This report contains: a a review of special considerations to be kept in mind when administering antiretroviral agents to pregnant women; b a current overview of the results of clinical and epidemiologic trials dealing with the prevention of perinatal transmission of HIV-1; c a look at the use of tests for measuring HIV-1 RNA (viral load during pregnancy; d the most recent recommendations on the use of antiretroviral chemoprophylaxis and elective cesarean section for reducing perinatal viral transmission. These recommendations apply to the United States, and other countries may prefer to use different approaches.

  9. ECHO virus

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/001340.htm ECHO virus To use the sharing features on this page, please enable JavaScript. Enteric cytopathic human orphan (ECHO) viruses are a group of viruses that can lead ...

  10. Causal Meta-Analysis : Methodology and Applications

    NARCIS (Netherlands)

    Bax, L.J.

    2009-01-01

    Meta-analysis is a statistical method to summarize research data from multiple studies in a quantitative manner. This dissertation addresses a number of methodological topics in causal meta-analysis and reports the development and validation of meta-analysis software. In the first (methodological)

  11. Information-causality and extremal tripartite correlations

    International Nuclear Information System (INIS)

    Yang, Tzyh Haur; Cavalcanti, Daniel; Almeida, Mafalda L; Teo, Colin; Scarani, Valerio

    2012-01-01

    We study the principle of information-causality (IC) in the presence of extremal no-signaling correlations on a tripartite scenario. We prove that all, except one, of the non-local correlations lead to violation of IC. The remaining non-quantum correlation is shown to satisfy any bipartite physical principle. (paper)

  12. Comments: Causal Interpretations of Mediation Effects

    Science.gov (United States)

    Jo, Booil; Stuart, Elizabeth A.

    2012-01-01

    The authors thank Dr. Lindsay Page for providing a nice illustration of the use of the principal stratification framework to define causal effects, and a Bayesian model for effect estimation. They hope that her well-written article will help expose education researchers to these concepts and methods, and move the field of mediation analysis in…

  13. Inductive reasoning about causally transmitted properties.

    Science.gov (United States)

    Shafto, Patrick; Kemp, Charles; Bonawitz, Elizabeth Baraff; Coley, John D; Tenenbaum, Joshua B

    2008-11-01

    Different intuitive theories constrain and guide inferences in different contexts. Formalizing simple intuitive theories as probabilistic processes operating over structured representations, we present a new computational model of category-based induction about causally transmitted properties. A first experiment demonstrates undergraduates' context-sensitive use of taxonomic and food web knowledge to guide reasoning about causal transmission and shows good qualitative agreement between model predictions and human inferences. A second experiment demonstrates strong quantitative and qualitative fits to inferences about a more complex artificial food web. A third experiment investigates human reasoning about complex novel food webs where species have known taxonomic relations. Results demonstrate a double-dissociation between the predictions of our causal model and a related taxonomic model [Kemp, C., & Tenenbaum, J. B. (2003). Learning domain structures. In Proceedings of the 25th annual conference of the cognitive science society]: the causal model predicts human inferences about diseases but not genes, while the taxonomic model predicts human inferences about genes but not diseases. We contrast our framework with previous models of category-based induction and previous formal instantiations of intuitive theories, and outline challenges in developing a complete model of context-sensitive reasoning.

  14. Exploring Causal Models of Educational Achievement.

    Science.gov (United States)

    Parkerson, Jo Ann; And Others

    1984-01-01

    This article evaluates five causal model of educational productivity applied to learning science in a sample of 882 fifth through eighth graders. Each model explores the relationship between achievement and a combination of eight constructs: home environment, peer group, media, ability, social environment, time on task, motivation, and…

  15. Sequential causal learning in humans and rats

    NARCIS (Netherlands)

    Lu, H.; Rojas, R.R.; Beckers, T.; Yuille, A.; Love, B.C.; McRae, K.; Sloutsky, V.M.

    2008-01-01

    Recent experiments (Beckers, De Houwer, Pineño, & Miller, 2005;Beckers, Miller, De Houwer, & Urushihara, 2006) have shown that pretraining with unrelated cues can dramatically influence the performance of humans in a causal learning paradigm and rats in a standard Pavlovian conditioning paradigm.

  16. The Causal Foundations of Structural Equation Modeling

    Science.gov (United States)

    2012-02-16

    and Baumrind (1993).” This, together with the steady influx of statisticians into the field, has left SEM re- searchers in a quandary about the...considerations. Journal of Personality and Social Psychology 51 1173–1182. Baumrind , D. (1993). Specious causal attributions in social sciences: The

  17. Causal Measurement Models: Can Criticism Stimulate Clarification?

    Science.gov (United States)

    Markus, Keith A.

    2016-01-01

    In their 2016 work, Aguirre-Urreta et al. provided a contribution to the literature on causal measurement models that enhances clarity and stimulates further thinking. Aguirre-Urreta et al. presented a form of statistical identity involving mapping onto the portion of the parameter space involving the nomological net, relationships between the…

  18. A quantum probability model of causal reasoning

    Directory of Open Access Journals (Sweden)

    Jennifer S Trueblood

    2012-05-01

    Full Text Available People can often outperform statistical methods and machine learning algorithms in situations that involve making inferences about the relationship between causes and effects. While people are remarkably good at causal reasoning in many situations, there are several instances where they deviate from expected responses. This paper examines three situations where judgments related to causal inference problems produce unexpected results and describes a quantum inference model based on the axiomatic principles of quantum probability theory that can explain these effects. Two of the three phenomena arise from the comparison of predictive judgments (i.e., the conditional probability of an effect given a cause with diagnostic judgments (i.e., the conditional probability of a cause given an effect. The third phenomenon is a new finding examining order effects in predictive causal judgments. The quantum inference model uses the notion of incompatibility among different causes to account for all three phenomena. Psychologically, the model assumes that individuals adopt different points of view when thinking about different causes. The model provides good fits to the data and offers a coherent account for all three causal reasoning effects thus proving to be a viable new candidate for modeling human judgment.

  19. A Causal Model of Faculty Turnover Intentions.

    Science.gov (United States)

    Smart, John C.

    1990-01-01

    A causal model assesses the relative influence of individual attributes, institutional characteristics, contextual-work environment variables, and multiple measures of job satisfaction on faculty intentions to leave their current institutions. Factors considered include tenure status, age, institutional status, governance style, organizational…

  20. Catastrophizing and Causal Beliefs in Whiplash

    NARCIS (Netherlands)

    Buitenhuis, J.; de Jong, P. J.; Jaspers, J. P. C.; Groothoff, J. W.

    2008-01-01

    Study Design. Prospective cohort study. Objective. This study investigates the role of pain catastrophizing and causal beliefs with regard to severity and persistence of neck complaints after motor vehicle accidents. Summary of Background Data. In previous research on low back pain, somatoform

  1. Probable autoimmune causal relationship between periodontitis and ...

    African Journals Online (AJOL)

    Periodontitis is a multifactorial disease with microbial dental plaque as the initiator of periodontal disease. However, the manifestation and progression of the disease is influenced by a wide variety of determinants and factors. The strongest type of causal relationship is the association of systemic and periodontal disease.

  2. On minimizers of causal variational principles

    International Nuclear Information System (INIS)

    Schiefeneder, Daniela

    2011-01-01

    Causal variational principles are a class of nonlinear minimization problems which arise in a formulation of relativistic quantum theory referred to as the fermionic projector approach. This thesis is devoted to a numerical and analytic study of the minimizers of a general class of causal variational principles. We begin with a numerical investigation of variational principles for the fermionic projector in discrete space-time. It is shown that for sufficiently many space-time points, the minimizing fermionic projector induces non-trivial causal relations on the space-time points. We then generalize the setting by introducing a class of causal variational principles for measures on a compact manifold. In our main result we prove under general assumptions that the support of a minimizing measure is either completely timelike, or it is singular in the sense that its interior is empty. In the examples of the circle, the sphere and certain flag manifolds, the general results are supplemented by a more detailed analysis of the minimizers. (orig.)

  3. Causality and analyticity in quantum fields theory

    International Nuclear Information System (INIS)

    Iagolnitzer, D.

    1992-01-01

    This is a presentation of results on the causal and analytical structure of Green functions and on the collision amplitudes in fields theories, for massive particles of one type, with a positive mass and a zero spin value. (A.B.)

  4. Causality and Time in Historical Institutionalism

    DEFF Research Database (Denmark)

    Mahoney, James; Mohamedali, Khairunnisa; Nguyen, Christoph

    2016-01-01

    This chapter explores the dual concern with causality and time in historical institutionalism using a graphical approach. The analysis focuses on three concepts that are central to this field: critical junctures, gradual change, and path dependence. The analysis makes explicit and formal the logi...

  5. Inductive Reasoning about Causally Transmitted Properties

    Science.gov (United States)

    Shafto, Patrick; Kemp, Charles; Bonawitz, Elizabeth Baraff; Coley, John D.; Tenenbaum, Joshua B.

    2008-01-01

    Different intuitive theories constrain and guide inferences in different contexts. Formalizing simple intuitive theories as probabilistic processes operating over structured representations, we present a new computational model of category-based induction about causally transmitted properties. A first experiment demonstrates undergraduates'…

  6. Black Hole Complementarity and Violation of Causality

    OpenAIRE

    Rozenblit, Moshe

    2017-01-01

    Analysis of a massive shell collapsing on a solid sphere shows that black hole complementarity (BHC) violates causality in its effort to save information conservation. In particular, this note describes a hypothetical contraption based on BHC that would allow the transfer of information from the future to the present.

  7. Encoding dependence in Bayesian causal networks

    Science.gov (United States)

    Bayesian networks (BNs) represent complex, uncertain spatio-temporal dynamics by propagation of conditional probabilities between identifiable states with a testable causal interaction model. Typically, they assume random variables are discrete in time and space with a static network structure that ...

  8. Causality in the semantics of Esterel : revisited

    NARCIS (Netherlands)

    Mousavi, M.R.; Klin, B.; Sobocinski, P.

    2010-01-01

    We re-examine the challenges concerning causality in the semantics of Esterel and show that they pertain to the known issues in the semantics of Structured Operational Semantics with negative premises. We show that the solutions offered for the semantics of SOS also provide answers to the semantic

  9. Scalar field Green functions on causal sets

    International Nuclear Information System (INIS)

    Nomaan Ahmed, S; Surya, Sumati; Dowker, Fay

    2017-01-01

    We examine the validity and scope of Johnston’s models for scalar field retarded Green functions on causal sets in 2 and 4 dimensions. As in the continuum, the massive Green function can be obtained from the massless one, and hence the key task in causal set theory is to first identify the massless Green function. We propose that the 2d model provides a Green function for the massive scalar field on causal sets approximated by any topologically trivial 2-dimensional spacetime. We explicitly demonstrate that this is indeed the case in a Riemann normal neighbourhood. In 4d the model can again be used to provide a Green function for the massive scalar field in a Riemann normal neighbourhood which we compare to Bunch and Parker’s continuum Green function. We find that the same prescription can also be used for de Sitter spacetime and the conformally flat patch of anti-de Sitter spacetime. Our analysis then allows us to suggest a generalisation of Johnston’s model for the Green function for a causal set approximated by 3-dimensional flat spacetime. (paper)

  10. Are bruxism and the bite causally related?

    NARCIS (Netherlands)

    Lobbezoo, F.; Ahlberg, J.; Manfredini, D.; Winocur, E.

    2012-01-01

    In the dental profession, the belief that bruxism and dental (mal-)occlusion (‘the bite’) are causally related is widespread. The aim of this review was to critically assess the available literature on this topic. A PubMed search of the English-language literature, using the query ‘Bruxism [Majr

  11. Causality relationship between energy demand and economic ...

    African Journals Online (AJOL)

    This paper attempts to examine the causal relationship between electricity demand and economic growth in Nigeria using data for 1970 – 2003. The study uses the Johansen cointegration VAR approach. The ADF and Phillips – Perron test statistics were used to test for stationarity of the data. It was found that the data were ...

  12. Profile of small interfering RNAs from cotton plants infected with the polerovirus Cotton leafroll dwarf virus

    Directory of Open Access Journals (Sweden)

    Schrago Carlos EG

    2011-08-01

    Full Text Available Abstract Background In response to infection, viral genomes are processed by Dicer-like (DCL ribonuclease proteins into viral small RNAs (vsRNAs of discrete sizes. vsRNAs are then used as guides for silencing the viral genome. The profile of vsRNAs produced during the infection process has been extensively studied for some groups of viruses. However, nothing is known about the vsRNAs produced during infections of members of the economically important family Luteoviridae, a group of phloem-restricted viruses. Here, we report the characterization of a population of vsRNAs from cotton plants infected with Cotton leafroll dwarf virus (CLRDV, a member of the genus Polerovirus, family Luteoviridae. Results Deep sequencing of small RNAs (sRNAs from leaves of CLRDV-infected cotton plants revealed that the vsRNAs were 21- to 24-nucleotides (nt long and that their sequences matched the viral genome, with higher frequencies of matches in the 3- region. There were equivalent amounts of sense and antisense vsRNAs, and the 22-nt class of small RNAs was predominant. During infection, cotton Dcl transcripts appeared to be up-regulated, while Dcl2 appeared to be down-regulated. Conclusions This is the first report on the profile of sRNAs in a plant infected with a virus from the family Luteoviridae. Our sequence data strongly suggest that virus-derived double-stranded RNA functions as one of the main precursors of vsRNAs. Judging by the profiled size classes, all cotton DCLs might be working to silence the virus. The possible causes for the unexpectedly high accumulation of 22-nt vsRNAs are discussed. CLRDV is the causal agent of Cotton blue disease, which occurs worldwide. Our results are an important contribution for understanding the molecular mechanisms involved in this and related diseases.

  13. Profile of small interfering RNAs from cotton plants infected with the polerovirus Cotton leafroll dwarf virus.

    Science.gov (United States)

    Silva, Tatiane F; Romanel, Elisson A C; Andrade, Roberto R S; Farinelli, Laurent; Østerås, Magne; Deluen, Cécile; Corrêa, Régis L; Schrago, Carlos E G; Vaslin, Maite F S

    2011-08-24

    In response to infection, viral genomes are processed by Dicer-like (DCL) ribonuclease proteins into viral small RNAs (vsRNAs) of discrete sizes. vsRNAs are then used as guides for silencing the viral genome. The profile of vsRNAs produced during the infection process has been extensively studied for some groups of viruses. However, nothing is known about the vsRNAs produced during infections of members of the economically important family Luteoviridae, a group of phloem-restricted viruses. Here, we report the characterization of a population of vsRNAs from cotton plants infected with Cotton leafroll dwarf virus (CLRDV), a member of the genus Polerovirus, family Luteoviridae. Deep sequencing of small RNAs (sRNAs) from leaves of CLRDV-infected cotton plants revealed that the vsRNAs were 21- to 24-nucleotides (nt) long and that their sequences matched the viral genome, with higher frequencies of matches in the 3- region. There were equivalent amounts of sense and antisense vsRNAs, and the 22-nt class of small RNAs was predominant. During infection, cotton Dcl transcripts appeared to be up-regulated, while Dcl2 appeared to be down-regulated. This is the first report on the profile of sRNAs in a plant infected with a virus from the family Luteoviridae. Our sequence data strongly suggest that virus-derived double-stranded RNA functions as one of the main precursors of vsRNAs. Judging by the profiled size classes, all cotton DCLs might be working to silence the virus. The possible causes for the unexpectedly high accumulation of 22-nt vsRNAs are discussed. CLRDV is the causal agent of Cotton blue disease, which occurs worldwide. Our results are an important contribution for understanding the molecular mechanisms involved in this and related diseases.

  14. Sharka: how do plants respond to Plum pox virus infection?

    Science.gov (United States)

    Clemente-Moreno, María J; Hernández, José A; Diaz-Vivancos, Pedro

    2015-01-01

    Plum pox virus (PPV), the causal agent of sharka disease, is one of the most studied plant viruses, and major advances in detection techniques, genome characterization and organization, gene expression, transmission, and the description of candidate genes involved in PPV resistance have been described. However, information concerning the plant response to PPV infection is very scarce. In this review, we provide an updated summary of the research carried out to date in order to elucidate how plants cope with PPV infection and their response at different levels, including the physiological, biochemical, proteomic, and genetic levels. Knowledge about how plants respond to PPV infection can contribute to the development of new strategies to cope with this disease. Due to the fact that PPV induces an oxidative stress in plants, the bio-fortification of the antioxidative defences, by classical or biotechnological approaches, would be a useful tool to cope with PPV infection. Nevertheless, there are still some gaps in knowledge related to PPV-plant interaction that remain to be filled, such as the effect of PPV on the hormonal profile of the plant or on the plant metabolome. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  15. Fate of Clavibacter michiganensis ssp. sepedonicus, the causal organism of bacterial ring rot in potato, in weeds and field crops.

    NARCIS (Netherlands)

    Wolf, van der J.M.; Beckhoven, van J.R.C.M.; Hukkanen, A.; Karjalainen, R.; Muller, P.

    2005-01-01

    Crops and weeds were tested for their ability to host Clavibacter michiganensis ssp. sepedonicus (Cms), the causal agent of bacterial ring rot in potato. Ten crops grown in rotation with potato in Europe, namely maize, wheat, barley, oat, bush bean, broad bean, rape, pea and onion and five cultivars

  16. BLACK-BACKED JACKAL EXPOSURE TO RABIES VIRUS, CANINE DISTEMPER VIRUS, AND BACILLUS ANTHRACIS IN ETOSHA NATIONAL PARK, NAMIBIA

    Science.gov (United States)

    Bellan, Steve E.; Cizauskas, Carrie A.; Miyen, Jacobeth; Ebersohn, Karen; Küsters, Martina; Prager, Katie; Van Vuuren, Moritz; Sabeta, Claude; Getz, Wayne M.

    2017-01-01

    Canine distemper virus (CDV) and rabies virus (RABV) occur worldwide in wild carnivore and domestic dog populations and pose threats to wildlife conservation and public health. In Etosha National Park (ENP), Namibia, anthrax is endemic and generates carcasses frequently fed on by an unusually dense population of black-backed jackals (Canis mesomelas). Using serology and phylogenetic analyses (on samples obtained from February, 2009 to July, 2010), and historical mortality records (1975–2011), we assessed jackal exposure to Bacillus anthracis (BA; the causal bacterial agent of anthrax), CDV, and RABV. Seroprevalence to all three pathogens was relatively high with 95% (n = 86), 73% (n = 86), and 9% (n = 81) of jackals exhibiting antibodies to BA, CDV, and RABV, respectively. Exposure to BA, as assessed with an anti-Protective Antigen ELISA test, increased significantly with age and all animals >1 yr old tested positive. Seroprevalence of exposure to CDV also increased significantly with age, with similar age-specific trends during both years of the study. No significant effect of age was found on RABV seroprevalence. Three of the seven animals exhibiting immunity to RABV were monitored for more than one year after sampling and did not succumb to the disease. Mortality records revealed that rabid animals are destroyed nearly every year inside the ENP tourist camps. Phylogenetic analyses demonstrated that jackal RABV in ENP is part of the same transmission cycle as other dog-jackal RABV cycles in Namibia. PMID:22493112

  17. Causal Factors for The Adoption Innovation Teacher’s Tv for Teachersand Educational Personnel

    Directory of Open Access Journals (Sweden)

    Thanadol Phuseerit

    2016-12-01

    aire for the experts to examine the causal factors for the adoption innovation teacher’s TV for teachers and education personnel model by focus groups, 4 questionnaire to confirm the causal factors to an innovation teacher’s TV model for teachers and educational personnel Committee of the teacher’s TV, 5 the causal factor for the adoption innovation teacher’s TV for teachers and education personnel model, 6 evaluation form of the causal factor for the adoption of the innovation teacher’s TV for teachers and education personnel model from the specialists. The research results were: 1 The causal factors for the adoption innovation teacher’s TV for Teachers and educational personnel Model. Elements and factors are as follows: 1.1 Elements of the causes and factors of innovation teacher’s TV. Teachers and educational personnel The Review of literature and semi-structured questionnaire, interviewing Collecting quality data from in-depth interviews with a total 9 causal as fallow: (1 Characteristics of innovation, included: relative Advantage, Compatibility, Complexity, Trial ability, Observable (2 Communication Channels, included: interpersonal communication, the media as press, radio, television, communication specialized media (3 Innovation-Decision Process, included: Knowledge, Persuasion, Decision, Implementation, Confirmation (4 Economy and Social System, include: compensation and benefits. Social interaction, (5 Attitude, included: understanding the emotions, behavior (6 Motivation, included: Intrinsic motivation. External motivation (7 Support of Administrator, include: support for innovation, the budget support and materials, Academic support (8 Change agent, included: knowledge and ability, Skill-oriented capabilities Ability attitude (9 Opinion Leaders, included: access to others easily, Creative and 1element of the Adoption of the Innovation: TTV, included: the perceived ease of use, and Perceived benefits. The model’s validity of the consistency

  18. Does Causality Matter More Now? Increase in the Proportion of Causal Language in English Texts.

    Science.gov (United States)

    Iliev, Rumen; Axelrod, Robert

    2016-05-01

    The vast majority of the work on culture and cognition has focused on cross-cultural comparisons, largely ignoring the dynamic aspects of culture. In this article, we provide a diachronic analysis of causal cognition over time. We hypothesized that the increased role of education, science, and technology in Western societies should be accompanied by greater attention to causal connections. To test this hypothesis, we compared word frequencies in English texts from different time periods and found an increase in the use of causal language of about 40% over the past two centuries. The observed increase was not attributable to general language effects or to changing semantics of causal words. We also found that there was a consistent difference between the 19th and the 20th centuries, and that the increase happened mainly in the 20th century. © The Author(s) 2016.

  19. An Immune Agent for Web-Based AI Course

    Science.gov (United States)

    Gong, Tao; Cai, Zixing

    2006-01-01

    To overcome weakness and faults of a web-based e-learning course such as Artificial Intelligence (AI), an immune agent was proposed, simulating a natural immune mechanism against a virus. The immune agent was built on the multi-dimension education agent model and immune algorithm. The web-based AI course was comprised of many files, such as HTML…

  20. Causal knowledge and the development of inductive reasoning.

    Science.gov (United States)

    Bright, Aimée K; Feeney, Aidan

    2014-06-01

    We explored the development of sensitivity to causal relations in children's inductive reasoning. Children (5-, 8-, and 12-year-olds) and adults were given trials in which they decided whether a property known to be possessed by members of one category was also possessed by members of (a) a taxonomically related category or (b) a causally related category. The direction of the causal link was either predictive (prey→predator) or diagnostic (predator→prey), and the property that participants reasoned about established either a taxonomic or causal context. There was a causal asymmetry effect across all age groups, with more causal choices when the causal link was predictive than when it was diagnostic. Furthermore, context-sensitive causal reasoning showed a curvilinear development, with causal choices being most frequent for 8-year-olds regardless of context. Causal inductions decreased thereafter because 12-year-olds and adults made more taxonomic choices when reasoning in the taxonomic context. These findings suggest that simple causal relations may often be the default knowledge structure in young children's inductive reasoning, that sensitivity to causal direction is present early on, and that children over-generalize their causal knowledge when reasoning. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Molecular characterization of Prunus necrotic ringspot virus isolated from rose in Brazil

    Directory of Open Access Journals (Sweden)

    Thor Vinícius Martins Fajardo

    2015-12-01

    Full Text Available ABSTRACT: There is no molecular characterization of Brazilian isolates of Prunus necrotic ringspot virus (PNRSV, except for those infecting peach. In this research, the causal agent of rose mosaic was determined and the movement (MP and coat (CP protein genes of a PNRSV isolate from rose were molecularly characterized for the first time in Brazil. The nucleotide and deduced amino acid sequences of MP and CP complete genes were aligned and compared with other isolates. Molecular analysis of the MP and CP nucleotide sequences of a Brazilian PNRSV isolate from rose and others from this same host showed highest identities of 96.7% and 98.6%, respectively, and Rose-Br isolate was classified in PV32 group.

  2. Human Papilloma Virus in Oral Squamous Cell Carcinoma - The Enigma Unravelled.

    Science.gov (United States)

    Khot, Komal P; Deshmane, Swati; Choudhari, Sheetal

    2016-03-01

    Squamous cell carcinoma of the head and neck (HNSCC) has long been regarded as a disease entity having a remarkable incidence worldwide and a fairly onerous prognosis; thus encouraging further research on factors that might modify disease outcome. Squamous cell carcinomas encompass at least 90% of all oral malignancies. Several factors like tobacco and tobacco-related products, alcohol, genetic predisposition and hormonal factors are suspected as possible causative factors. Human papilloma virus (HPV), the causal agent of cervical cancer also appears to be involved in the aetiology of oral and oropharyngeal cancer. HPVpositive squamous cell carcinoma (SCC) seems to differ from HPV-negative SCC. Many questions about the natural history of oral HPV infection remain under investigation. The aim of this review is to highlight the current understanding of HPV-associated oral cancer with an emphasis on its prognosis, detection and management.

  3. The causal link between energy and output growth: Evidence from Markov switching Granger causality

    International Nuclear Information System (INIS)

    Kandemir Kocaaslan, Ozge

    2013-01-01

    In this paper we empirically investigate the causal link between energy consumption and economic growth employing a Markov switching Granger causality analysis. We carry out our investigation using annual U.S. real GDP, total final energy consumption and total primary energy consumption data which cover the period between 1968 and 2010. We find that there are significant changes in the causal relation between energy consumption and economic growth over the sample period under investigation. Our results show that total final energy consumption and total primary energy consumption have significant predictive content for real economic activity in the U.S. economy. Furthermore, the causality running from energy consumption to output growth seems to be strongly apparent particularly during the periods of economic downturn and energy crisis. We also document that output growth has predictive power in explaining total energy consumption. Furthermore, the power of output growth in predicting total energy consumption is found to diminish after the mid of 1980s. - Highlights: • Total energy consumption has predictive content for real economic activity. • The causality from energy to output growth is apparent in the periods of recession. • The causality from energy to output growth is strong in the periods of energy crisis. • Output growth has predictive power in explaining total energy consumption. • The power of output growth in explaining energy diminishes after the mid of 1980s

  4. Beet necrotic yellow vein virus accumulates inside resting spores and zoosporangia of its vector Polymyxa betae BNYVV infects P. betae

    Directory of Open Access Journals (Sweden)

    Payton Mark

    2007-04-01

    Full Text Available Abstract Background Plasmodiophorids and chytrids are zoosporic parasites of algae and land plant and are distributed worldwide. There are 35 species belonging to the order Plasmodiophorales and three species, Polymyxa betae, P. graminis, and Spongospora subterranea, are plant viral vectors. Plasmodiophorid transmitted viruses are positive strand RNA viruses belonging to five genera. Beet necrotic yellow vein virus (BNYVV and its vector, P. betae, are the causal agents for rhizomania. Results Evidence of BNYVV replication and movement proteins associating with P. betae resting spores was initially obtained using immunofluorescence labeling and well characterized antisera to each of the BNYVV proteins. Root cross sections were further examined using immunogold labeling and electron microscopy. BNYVV proteins translated from each of the four genomic and subgenomic RNAs accumulate inside P. betae resting spores and zoospores. Statistical analysis was used to determine if immunolabelling detected viral proteins in specific subcellular domains and at a level greater than in control samples. Conclusion Virus-like particles were detected in zoosporangia. Association of BNYVV replication and movement proteins with sporangial and sporogenic stages of P. betae suggest that BNYVV resides inside its vector during more than one life cycle stage. These data suggest that P. betae might be a host as well as a vector for BNYVV

  5. Beet necrotic yellow vein virus accumulates inside resting spores and zoosporangia of its vector Polymyxa betae BNYVV infects P. betae.

    Science.gov (United States)

    Lubicz, Jeanmarie Verchot; Rush, Charles M; Payton, Mark; Colberg, Terry

    2007-04-05

    Plasmodiophorids and chytrids are zoosporic parasites of algae and land plant and are distributed worldwide. There are 35 species belonging to the order Plasmodiophorales and three species, Polymyxa betae, P. graminis, and Spongospora subterranea, are plant viral vectors. Plasmodiophorid transmitted viruses are positive strand RNA viruses belonging to five genera. Beet necrotic yellow vein virus (BNYVV) and its vector, P. betae, are the causal agents for rhizomania. Evidence of BNYVV replication and movement proteins associating with P. betae resting spores was initially obtained using immunofluorescence labeling and well characterized antisera to each of the BNYVV proteins. Root cross sections were further examined using immunogold labeling and electron microscopy. BNYVV proteins translated from each of the four genomic and subgenomic RNAs accumulate inside P. betae resting spores and zoospores. Statistical analysis was used to determine if immunolabelling detected viral proteins in specific subcellular domains and at a level greater than in control samples. Virus-like particles were detected in zoosporangia. Association of BNYVV replication and movement proteins with sporangial and sporogenic stages of P. betae suggest that BNYVV resides inside its vector during more than one life cycle stage. These data suggest that P. betae might be a host as well as a vector for BNYVV.

  6. Elements of Causal Inference: Foundations and Learning Algorithms

    DEFF Research Database (Denmark)

    Peters, Jonas Martin; Janzing, Dominik; Schölkopf, Bernhard

    A concise and self-contained introduction to causal inference, increasingly important in data science and machine learning......A concise and self-contained introduction to causal inference, increasingly important in data science and machine learning...

  7. The causal relationship between Foreign Direct Investment (FDI ...

    African Journals Online (AJOL)

    The causal relationship between Foreign Direct Investment (FDI) and the ... of selected west African countries: Panel ARDL/Granger Causality Analysis. ... among this developing countries and an important revelation for policy implication.

  8. Virus en Endodoncia

    OpenAIRE

    Hernández Vigueras, Scarlette; Salazar Navarrete, Luis; Pérez Tomás, Ricardo; Segura Egea, Juan José; Viñas, Miguel; López-López, José

    2014-01-01

    La infección endodóntica es la infección que afecta al sistema de conductos radiculares y, sin duda, es el principal agente etiológico de las periodontitis apicales. Además, de las bacterias patógenas endodónticas, se ha buscado en los últimos años asociar la presencia de virus en distintos tipos de patología endodóntica. Los virus que más se han buscado y asociado son los pertenecientes a la familia herpesvirus, los cuales se han encontrado presentes en patologías periapicales principalmente...

  9. The Hankel transform of causal distributions

    Directory of Open Access Journals (Sweden)

    Manuel A. Aguirre T.

    2012-03-01

    Full Text Available In this note we evaluate the unidimensional distributional Hankel transform of \\dfrac{x^{\\alpha-1}_{+}}{\\Gamma^{\\alpha}},\\dfrac{x^{\\alpha-1}_{-}}{\\Gamma^{\\alpha}},dfrac{|x|^{\\alpha-1}}{\\Gamma^{\\frac{\\alpha}{2}}},dfrac{|x|^{\\alpha-1}sgn(x}{\\Gamma^{\\frac{\\alpha +1}{2}}} and (x± i0^{\\alpha-1} and then we extend the formulae to certain kinds of n-dimensional distributions calles "causal" and "anti-causal" distributions. We evaluate the distributional Handel transform of \\dfrac{(m^2+P^{\\alpha -1}_{-}}{\\Gamma^{(\\alpha} }, \\dfrac{|m^2+P|^{\\alpha -1}_{-}}{\\Gamma^{(\\frac{\\alpha}{2}}}, \\dfrac{|m^2+P|^{\\alpha -1}sgn(m^2+P}{\\Gamma (\\frac{\\alpha +1}{2 }} and (m^2+P±i0^{\\alpha-1}

  10. A new spin on causality constraints

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, Thomas; Jain, Sachin; Kundu, Sandipan [Department of Physics, Cornell University, Ithaca, New York (United States)

    2016-10-26

    Causality in a shockwave state is related to the analytic properties of a four-point correlation function. Extending recent results for scalar probes, we show that this constrains the couplings of the stress tensor to light spinning operators in conformal field theory, and interpret these constraints in terms of the interaction with null energy. For spin-1 and spin-2 conserved currents in four dimensions, the resulting inequalities are a subset of the Hofman-Maldacena conditions for positive energy deposition. It is well known that energy conditions in holographic theories are related to causality on the gravity side; our results make a connection on the CFT side, and extend it to non-holographic theories.

  11. Reciprocity, passivity and causality in Willis materials.

    Science.gov (United States)

    Muhlestein, Michael B; Sieck, Caleb F; Alù, Andrea; Haberman, Michael R

    2016-10-01

    Materials that require coupling between the stress-strain and momentum-velocity constitutive relations were first proposed by Willis (Willis 1981 Wave Motion 3 , 1-11. (doi:10.1016/0165-2125(81)90008-1)) and are now known as elastic materials of the Willis type, or simply Willis materials. As coupling between these two constitutive equations is a generalization of standard elastodynamic theory, restrictions on the physically admissible material properties for Willis materials should be similarly generalized. This paper derives restrictions imposed on the material properties of Willis materials when they are assumed to be reciprocal, passive and causal. Considerations of causality and low-order dispersion suggest an alternative formulation of the standard Willis equations. The alternative formulation provides improved insight into the subwavelength physical behaviour leading to Willis material properties and is amenable to time-domain analyses. Finally, the results initially obtained for a generally elastic material are specialized to the acoustic limit.

  12. Granger-Causality Maps of Diffusion Processes

    Czech Academy of Sciences Publication Activity Database

    Wahl, B.; Feudel, U.; Hlinka, Jaroslav; Wächter, M.; Peinke, J.; Freund, J.A.

    2016-01-01

    Roč. 93, č. 2 16 February (2016), č. článku 022213. ISSN 2470-0045 R&D Projects: GA ČR GA13-23940S; GA MZd(CZ) NV15-29835A Institutional support: RVO:67985807 Keywords : Granger causality * stochastic process * diffusion process * nonlinear dynamical systems Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 2.366, year: 2016

  13. Curvature constraints from the causal entropic principle

    International Nuclear Information System (INIS)

    Bozek, Brandon; Albrecht, Andreas; Phillips, Daniel

    2009-01-01

    Current cosmological observations indicate a preference for a cosmological constant that is drastically smaller than what can be explained by conventional particle physics. The causal entropic principle (Bousso et al.) provides an alternative approach to anthropic attempts to predict our observed value of the cosmological constant by calculating the entropy created within a causal diamond. We have extended this work to use the causal entropic principle to predict the preferred curvature within the 'multiverse'. We have found that values larger than ρ k =40ρ m are disfavored by more than 99.99% peak value at ρ Λ =7.9x10 -123 and ρ k =4.3ρ m for open universes. For universes that allow only positive curvature or both positive and negative curvature, we find a correlation between curvature and dark energy that leads to an extended region of preferred values. Our universe is found to be disfavored to an extent depending on the priors on curvature. We also provide a comparison to previous anthropic constraints on open universes and discuss future directions for this work.

  14. Structure induction in diagnostic causal reasoning.

    Science.gov (United States)

    Meder, Björn; Mayrhofer, Ralf; Waldmann, Michael R

    2014-07-01

    Our research examines the normative and descriptive adequacy of alternative computational models of diagnostic reasoning from single effects to single causes. Many theories of diagnostic reasoning are based on the normative assumption that inferences from an effect to its cause should reflect solely the empirically observed conditional probability of cause given effect. We argue against this assumption, as it neglects alternative causal structures that may have generated the sample data. Our structure induction model of diagnostic reasoning takes into account the uncertainty regarding the underlying causal structure. A key prediction of the model is that diagnostic judgments should not only reflect the empirical probability of cause given effect but should also depend on the reasoner's beliefs about the existence and strength of the link between cause and effect. We confirmed this prediction in 2 studies and showed that our theory better accounts for human judgments than alternative theories of diagnostic reasoning. Overall, our findings support the view that in diagnostic reasoning people go "beyond the information given" and use the available data to make inferences on the (unobserved) causal rather than on the (observed) data level. (c) 2014 APA, all rights reserved.

  15. Causal inference of asynchronous audiovisual speech

    Directory of Open Access Journals (Sweden)

    John F Magnotti

    2013-11-01

    Full Text Available During speech perception, humans integrate auditory information from the voice with visual information from the face. This multisensory integration increases perceptual precision, but only if the two cues come from the same talker; this requirement has been largely ignored by current models of speech perception. We describe a generative model of multisensory speech perception that includes this critical step of determining the likelihood that the voice and face information have a common cause. A key feature of the model is that it is based on a principled analysis of how an observer should solve this causal inference problem using the asynchrony between two cues and the reliability of the cues. This allows the model to make predictions abut the behavior of subjects performing a synchrony judgment task, predictive power that does not exist in other approaches, such as post hoc fitting of Gaussian curves to behavioral data. We tested the model predictions against the performance of 37 subjects performing a synchrony judgment task viewing audiovisual speech under a variety of manipulations, including varying asynchronies, intelligibility, and visual cue reliability. The causal inference model outperformed the Gaussian model across two experiments, providing a better fit to the behavioral data with fewer parameters. Because the causal inference model is derived from a principled understanding of the task, model parameters are directly interpretable in terms of stimulus and subject properties.

  16. A developmental approach to learning causal models for cyber security

    Science.gov (United States)

    Mugan, Jonathan

    2013-05-01

    To keep pace with our adversaries, we must expand the scope of machine learning and reasoning to address the breadth of possible attacks. One approach is to employ an algorithm to learn a set of causal models that describes the entire cyber network and each host end node. Such a learning algorithm would run continuously on the system and monitor activity in real time. With a set of causal models, the algorithm could anticipate novel attacks, take actions to thwart them, and predict the second-order effects flood of information, and the algorithm would have to determine which streams of that flood were relevant in which situations. This paper will present the results of efforts toward the application of a developmental learning algorithm to the problem of cyber security. The algorithm is modeled on the principles of human developmental learning and is designed to allow an agent to learn about the computer system in which it resides through active exploration. Children are flexible learners who acquire knowledge by actively exploring their environment and making predictions about what they will find,1, 2 and our algorithm is inspired by the work of the developmental psychologist Jean Piaget.3 Piaget described how children construct knowledge in stages and learn new concepts on top of those they already know. Developmental learning allows our algorithm to focus on subsets of the environment that are most helpful for learning given its current knowledge. In experiments, the algorithm was able to learn the conditions for file exfiltration and use that knowledge to protect sensitive files.

  17. Mind and Meaning: Piaget and Vygotsky on Causal Explanation.

    Science.gov (United States)

    Beilin, Harry

    1996-01-01

    Piaget's theory has been characterized as descriptive and not explanatory, not qualifying as causal explanation. Piaget was consistent in showing how his theory was both explanatory and causal. Vygotsky also endorsed causal-genetic explanation but, on the basis of knowledge of only Piaget's earliest works, he claimed that Piaget's theory was not…

  18. How to Be Causal: Time, Spacetime and Spectra

    Science.gov (United States)

    Kinsler, Paul

    2011-01-01

    I explain a simple definition of causality in widespread use, and indicate how it links to the Kramers-Kronig relations. The specification of causality in terms of temporal differential equations then shows us the way to write down dynamical models so that their causal nature "in the sense used here" should be obvious to all. To extend existing…

  19. Causal Relations and Feature Similarity in Children's Inductive Reasoning

    Science.gov (United States)

    Hayes, Brett K.; Thompson, Susan P.

    2007-01-01

    Four experiments examined the development of property induction on the basis of causal relations. In the first 2 studies, 5-year-olds, 8-year-olds, and adults were presented with triads in which a target instance was equally similar to 2 inductive bases but shared a causal antecedent feature with 1 of them. All 3 age groups used causal relations…

  20. Animal Models of Virus-Induced Neurobehavioral Sequelae: Recent Advances, Methodological Issues, and Future Prospects

    Directory of Open Access Journals (Sweden)

    Marco Bortolato

    2010-01-01

    Full Text Available Converging lines of clinical and epidemiological evidence suggest that viral infections in early developmental stages may be a causal factor in neuropsychiatric disorders such as schizophrenia, bipolar disorder, and autism-spectrum disorders. This etiological link, however, remains controversial in view of the lack of consistent and reproducible associations between viruses and mental illness. Animal models of virus-induced neurobehavioral disturbances afford powerful tools to test etiological hypotheses and explore pathophysiological mechanisms. Prenatal or neonatal inoculations of neurotropic agents (such as herpes-, influenza-, and retroviruses in rodents result in a broad spectrum of long-term alterations reminiscent of psychiatric abnormalities. Nevertheless, the complexity of these sequelae often poses methodological and interpretational challenges and thwarts their characterization. The recent conceptual advancements in psychiatric nosology and behavioral science may help determine new heuristic criteria to enhance the translational value of these models. A particularly critical issue is the identification of intermediate phenotypes, defined as quantifiable factors representing single neurochemical, neuropsychological, or neuroanatomical aspects of a diagnostic category. In this paper, we examine how the employment of these novel concepts may lead to new methodological refinements in the study of virus-induced neurobehavioral sequelae through animal models.

  1. Das Epstein-Barr-Virus ( = Epstein-Barr virus)

    OpenAIRE

    Niller, H. H.; Wolf, Hans J.

    1993-01-01

    Epstein-Barr virus is an ubiquitous humanpathogenic herpesvirus. It has been identified as the etiologic agent of infectious mononucleosis. In addition it is associated with the cancers nasopharyngeal carcinoma and Burkitt's lymphoma. Like other herpesviruses it infects cells in a lytic way or it persists in a latent state. Classically, the serologic diagnosis of Epstein-Barr virus infections is done by the agglutination of sheep erythrocytes according to Paul and Bunnell as a rapid testing m...

  2. Causal beliefs about depression in different cultural groups—what do cognitive psychological theories of causal learning and reasoning predict?

    OpenAIRE

    Hagmayer, York; Engelmann, Neele

    2014-01-01

    Cognitive psychological research focuses on causal learning and reasoning while cognitive anthropological and social science research tend to focus on systems of beliefs. Our aim was to explore how these two types of research can inform each other. Cognitive psychological theories (causal model theory and causal Bayes nets) were used to derive predictions for systems of causal beliefs. These predictions were then applied to lay theories of depression as a specific test case. A systematic lite...

  3. Hyperthermophilic Archaeal Viruses as Novel Nanoplatforms

    DEFF Research Database (Denmark)

    Uldahl, Kristine Buch

    Viruses are the most abundant biological entities on earth, and with an estimated 1031 virus-like particles in the biosphere, viruses are virtually everywhere. Traditionally, the study of viruses has focused on their roles as infectious agents. However, over the last decades with the development...... presents an in depth investigation of the hyperthermophilic archaeal virus SMV. Decisive steps in the viral life-cycle are studied with focus on the early stages of infection. TEM observations suggest that SMV1 virions enter into host cells via a fusion entry mechanism, involving three distinct stages...

  4. Structure and Connectivity Analysis of Financial Complex System Based on G-Causality Network

    International Nuclear Information System (INIS)

    Xu Chuan-Ming; Yan Yan; Zhu Xiao-Wu; Li Xiao-Teng; Chen Xiao-Song

    2013-01-01

    The recent financial crisis highlights the inherent weaknesses of the financial market. To explore the mechanism that maintains the financial market as a system, we study the interactions of U.S. financial market from the network perspective. Applied with conditional Granger causality network analysis, network density, in-degree and out-degree rankings are important indicators to analyze the conditional causal relationships among financial agents, and further to assess the stability of U.S. financial systems. It is found that the topological structure of G-causality network in U.S. financial market changed in different stages over the last decade, especially during the recent global financial crisis. Network density of the G-causality model is much higher during the period of 2007–2009 crisis stage, and it reaches the peak value in 2008, the most turbulent time in the crisis. Ranked by in-degrees and out-degrees, insurance companies are listed in the top of 68 financial institutions during the crisis. They act as the hubs which are more easily influenced by other financial institutions and simultaneously influence others during the global financial disturbance. (interdisciplinary physics and related areas of science and technology)

  5. Structure and Connectivity Analysis of Financial Complex System Based on G-Causality Network

    Science.gov (United States)

    Xu, Chuan-Ming; Yan, Yan; Zhu, Xiao-Wu; Li, Xiao-Teng; Chen, Xiao-Song

    2013-11-01

    The recent financial crisis highlights the inherent weaknesses of the financial market. To explore the mechanism that maintains the financial market as a system, we study the interactions of U.S. financial market from the network perspective. Applied with conditional Granger causality network analysis, network density, in-degree and out-degree rankings are important indicators to analyze the conditional causal relationships among financial agents, and further to assess the stability of U.S. financial systems. It is found that the topological structure of G-causality network in U.S. financial market changed in different stages over the last decade, especially during the recent global financial crisis. Network density of the G-causality model is much higher during the period of 2007-2009 crisis stage, and it reaches the peak value in 2008, the most turbulent time in the crisis. Ranked by in-degrees and out-degrees, insurance companies are listed in the top of 68 financial institutions during the crisis. They act as the hubs which are more easily influenced by other financial institutions and simultaneously influence others during the global financial disturbance.

  6. A Bayesian Theory of Sequential Causal Learning and Abstract Transfer.

    Science.gov (United States)

    Lu, Hongjing; Rojas, Randall R; Beckers, Tom; Yuille, Alan L

    2016-03-01

    Two key research issues in the field of causal learning are how people acquire causal knowledge when observing data that are presented sequentially, and the level of abstraction at which learning takes place. Does sequential causal learning solely involve the acquisition of specific cause-effect links, or do learners also acquire knowledge about abstract causal constraints? Recent empirical studies have revealed that experience with one set of causal cues can dramatically alter subsequent learning and performance with entirely different cues, suggesting that learning involves abstract transfer, and such transfer effects involve sequential presentation of distinct sets of causal cues. It has been demonstrated that pre-training (or even post-training) can modulate classic causal learning phenomena such as forward and backward blocking. To account for these effects, we propose a Bayesian theory of sequential causal learning. The theory assumes that humans are able to consider and use several alternative causal generative models, each instantiating a different causal integration rule. Model selection is used to decide which integration rule to use in a given learning environment in order to infer causal knowledge from sequential data. Detailed computer simulations demonstrate that humans rely on the abstract characteristics of outcome variables (e.g., binary vs. continuous) to select a causal integration rule, which in turn alters causal learning in a variety of blocking and overshadowing paradigms. When the nature of the outcome variable is ambiguous, humans select the model that yields the best fit with the recent environment, and then apply it to subsequent learning tasks. Based on sequential patterns of cue-outcome co-occurrence, the theory can account for a range of phenomena in sequential causal learning, including various blocking effects, primacy effects in some experimental conditions, and apparently abstract transfer of causal knowledge. Copyright © 2015

  7. Comparative analysis of virus-derived small RNAs within cassava (Manihot esculenta Crantz) infected with cassava brown streak viruses.

    Science.gov (United States)

    Ogwok, Emmanuel; Ilyas, Muhammad; Alicai, Titus; Rey, Marie E C; Taylor, Nigel J

    2016-04-02

    Infection of plant cells by viral pathogens triggers RNA silencing, an innate antiviral defense mechanism. In response to infection, small RNAs (sRNAs) are produced that associate with Argonaute (AGO)-containing silencing complexes which act to inactivate viral genomes by posttranscriptional gene silencing (PTGS). Deep sequencing was used to compare virus-derived small RNAs (vsRNAs) in cassava genotypes NASE 3, TME 204 and 60444 infected with the positive sense single-stranded RNA (+ssRNA) viruses cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV), the causal agents of cassava brown streak disease (CBSD). An abundance of 21-24nt vsRNAs was detected and mapped, covering the entire CBSV and UCBSV genomes. The 21nt vsRNAs were most predominant, followed by the 22 nt class with a slight bias toward sense compared to antisense polarity, and a bias for adenine and uracil bases present at the 5'-terminus. Distribution and frequency of vsRNAs differed between cassava genotypes and viral genomes. In susceptible genotypes TME 204 and 60444, CBSV-derived sRNAs were seen in greater abundance than UCBSV-derived sRNAs. NASE 3, known to be resistant to UCBSV, accumulated negligible UCBSV-derived sRNAs but high populations of CBSV-derived sRNAs. Transcript levels of cassava homologues of AGO2, DCL2 and DCL4, which are central to the gene-silencing complex, were found to be differentially regulated in CBSV- and UCBSV-infected plants across genotypes, suggesting these proteins play a role in antiviral defense. Irrespective of genotype or viral pathogen, maximum populations of vsRNAs mapped to the cytoplasmic inclusion, P1 and P3 protein-encoding regions. Our results indicate disparity between CBSV and UCBSV host-virus interaction mechanisms, and provide insight into the role of virus-induced gene silencing as a mechanism of resistance to CBSD. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  8. Análisis proteómico de Plasmodium, el agente causal de la malaria Proteomic analysis of Plasmodium, the causal agent of Malaria

    Directory of Open Access Journals (Sweden)

    Ivone Castro R

    2009-01-01

    Full Text Available Los plasmodios son protozoarios cuyo complejo ciclo de vida se lleva a cabo en dos hospederos, el vertebrado y el mosquito. La infección de los seres humanos produce la enfermedad conocida como malaria. La secuenciación del genoma de Plasmodium falciparum y el desarrollo de la proteómica han permitido un gran avance en el conocimiento de la biología de este letal parásito. La presente revisión se centra en describir los logros recientes en el estudio del proteoma de Plasmodium falciparum y algunas de las implicaciones en la búsqueda de nuevos fármacos antimaláricos, así como en la generación de vacunas para el control de la enfermedad.Plasmodia are protozoa whose complex life cycle takes place in two different hosts, the vertebrate and the mosquito. The human infection produces the malaria disease. The genome sequence of Plasmodium falciparum and the proteomic tools have enabled a huge advance in knowledge of the biology of this parasite. This review will focus on the recent advances in proteomic studies of Plasmodium falciparum and some implications for the search of new antimalarial drugs as well as vaccines for the control of the disease.

  9. [Biological agents].

    Science.gov (United States)

    Amano, Koichi

    2009-03-01

    There are two types of biological agents for the treatment of rheumatoid arthritis (RA); monoclonal antibodies and recombinant proteins. Among the latter, etanercept, a recombinant fusion protein of soluble TNF receptor and IgG was approved in 2005 in Japan. The post-marketing surveillance of 13,894 RA patients revealed the efficacy and safety profiles of etanercept in the Japanese population, as well as overseas studies. Abatacept, a recombinant fusion protein of CTLA4 and IgG, is another biological agent for RA. Two clinical trials disclosed the efficacy of abatacept for difficult-to-treat patients: the AIM for MTX-resistant cases and the ATTAIN for patients who are resistant to anti-TNF. The ATTEST trial suggested abatacept might have more acceptable safety profile than infliximab. These biologics are also promising for the treatment of RA for not only relieving clinical symptoms and signs but retarding structural damage.

  10. Information causality from an entropic and a probabilistic perspective

    International Nuclear Information System (INIS)

    Al-Safi, Sabri W.; Short, Anthony J.

    2011-01-01

    The information causality principle is a generalization of the no-signaling principle which implies some of the known restrictions on quantum correlations. But despite its clear physical motivation, information causality is formulated in terms of a rather specialized game and figure of merit. We explore different perspectives on information causality, discussing the probability of success as the figure of merit, a relation between information causality and the nonlocal ''inner-product game,'' and the derivation of a quadratic bound for these games. We then examine an entropic formulation of information causality with which one can obtain the same results, arguably in a simpler fashion.

  11. Interactions of information transfer along separable causal paths

    Science.gov (United States)

    Jiang, Peishi; Kumar, Praveen

    2018-04-01

    Complex systems arise as a result of interdependences between multiple variables, whose causal interactions can be visualized in a time-series graph. Transfer entropy and information partitioning approaches have been used to characterize such dependences. However, these approaches capture net information transfer occurring through a multitude of pathways involved in the interaction and as a result mask our ability to discern the causal interaction within a subgraph of interest through specific pathways. We build on recent developments of momentary information transfer along causal paths proposed by Runge [Phys. Rev. E 92, 062829 (2015), 10.1103/PhysRevE.92.062829] to develop a framework for quantifying information partitioning along separable causal paths. Momentary information transfer along causal paths captures the amount of information transfer between any two variables lagged at two specific points in time. Our approach expands this concept to characterize the causal interaction in terms of synergistic, unique, and redundant information transfer through separable causal paths. Through a graphical model, we analyze the impact of the separable and nonseparable causal paths and the causality structure embedded in the graph as well as the noise effect on information partitioning by using synthetic data generated from two coupled logistic equation models. Our approach can provide a valuable reference for an autonomous information partitioning along separable causal paths which form a causal subgraph influencing a target.

  12. The selective power of causality on memory errors.

    Science.gov (United States)

    Marsh, Jessecae K; Kulkofsky, Sarah

    2015-01-01

    We tested the influence of causal links on the production of memory errors in a misinformation paradigm. Participants studied a set of statements about a person, which were presented as either individual statements or pairs of causally linked statements. Participants were then provided with causally plausible and causally implausible misinformation. We hypothesised that studying information connected with causal links would promote representing information in a more abstract manner. As such, we predicted that causal information would not provide an overall protection against memory errors, but rather would preferentially help in the rejection of misinformation that was causally implausible, given the learned causal links. In two experiments, we measured whether the causal linkage of information would be generally protective against all memory errors or only selectively protective against certain types of memory errors. Causal links helped participants reject implausible memory lures, but did not protect against plausible lures. Our results suggest that causal information may promote an abstract storage of information that helps prevent only specific types of memory errors.

  13. 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

  14. Causal asymmetry across cultures: Assigning causal roles in symmetric physical settings

    Directory of Open Access Journals (Sweden)

    Andrea eBender

    2011-09-01

    Full Text Available In the cognitive sciences, causal cognition in the physical domain has featured as a core research topic, but the impact of culture has been rarely ever explored. One case in point for a topic on which this neglect is pronounced is the pervasive tendency of people to consider one of two (equally important entities as more important for bringing about an effect. In order to scrutinize how robust such tendencies are across cultures, we asked German and Tongan participants to assign prime causality in nine symmetric settings. For most settings, strong asymmetries in both cultures were found, but not always in the same direction, depending on the task content. This indicates that causal asymmetries, while indeed being a robust phenomenon across cultures, are also subject to culture-specific concepts. Moreover, the asymmetries were found to be modulated by figure-ground relations, but not by marking agency.

  15. How multiple causes combine: independence constraints on causal inference.

    Science.gov (United States)

    Liljeholm, Mimi

    2015-01-01

    According to the causal power view, two core constraints-that causes occur independently (i.e., no confounding) and influence their effects independently-serve as boundary conditions for causal induction. This study investigated how violations of these constraints modulate uncertainty about the existence and strength of a causal relationship. Participants were presented with pairs of candidate causes that were either confounded or not, and that either interacted or exerted their influences independently. Consistent with the causal power view, uncertainty about the existence and strength of causal relationships was greater when causes were confounded or interacted than when unconfounded and acting independently. An elemental Bayesian causal model captured differences in uncertainty due to confounding but not those due to an interaction. Implications of distinct sources of uncertainty for the selection of contingency information and causal generalization are discussed.

  16. Toxicology and Epidemiology: Improving the Science with a Framework for Combining Toxicological and Epidemiological Evidence to Establish Causal Inference

    Science.gov (United States)

    Adami, Hans-Olov; Berry, Sir Colin L.; Breckenridge, Charles B.; Smith, Lewis L.; Swenberg, James A.; Trichopoulos, Dimitrios; Weiss, Noel S.; Pastoor, Timothy P.

    2011-01-01

    Historically, toxicology has played a significant role in verifying conclusions drawn on the basis of epidemiological findings. Agents that were suggested to have a role in human diseases have been tested in animals to firmly establish a causative link. Bacterial pathogens are perhaps the oldest examples, and tobacco smoke and lung cancer and asbestos and mesothelioma provide two more recent examples. With the advent of toxicity testing guidelines and protocols, toxicology took on a role that was intended to anticipate or predict potential adverse effects in humans, and epidemiology, in many cases, served a role in verifying or negating these toxicological predictions. The coupled role of epidemiology and toxicology in discerning human health effects by environmental agents is obvious, but there is currently no systematic and transparent way to bring the data and analysis of the two disciplines together in a way that provides a unified view on an adverse causal relationship between an agent and a disease. In working to advance the interaction between the fields of toxicology and epidemiology, we propose here a five-step “Epid-Tox” process that would focus on: (1) collection of all relevant studies, (2) assessment of their quality, (3) evaluation of the weight of evidence, (4) assignment of a scalable conclusion, and (5) placement on a causal relationship grid. The causal relationship grid provides a clear view of how epidemiological and toxicological data intersect, permits straightforward conclusions with regard to a causal relationship between agent and effect, and can show how additional data can influence conclusions of causality. PMID:21561883

  17. Emergent Geometry from Entropy and Causality

    Science.gov (United States)

    Engelhardt, Netta

    In this thesis, we investigate the connections between the geometry of spacetime and aspects of quantum field theory such as entanglement entropy and causality. This work is motivated by the idea that spacetime geometry is an emergent phenomenon in quantum gravity, and that the physics responsible for this emergence is fundamental to quantum field theory. Part I of this thesis is focused on the interplay between spacetime and entropy, with a special emphasis on entropy due to entanglement. In general spacetimes, there exist locally-defined surfaces sensitive to the geometry that may act as local black hole boundaries or cosmological horizons; these surfaces, known as holographic screens, are argued to have a connection with the second law of thermodynamics. Holographic screens obey an area law, suggestive of an association with entropy; they are also distinguished surfaces from the perspective of the covariant entropy bound, a bound on the total entropy of a slice of the spacetime. This construction is shown to be quite general, and is formulated in both classical and perturbatively quantum theories of gravity. The remainder of Part I uses the Anti-de Sitter/ Conformal Field Theory (AdS/CFT) correspondence to both expand and constrain the connection between entanglement entropy and geometry. The AdS/CFT correspondence posits an equivalence between string theory in the "bulk" with AdS boundary conditions and certain quantum field theories. In the limit where the string theory is simply classical General Relativity, the Ryu-Takayanagi and more generally, the Hubeny-Rangamani-Takayanagi (HRT) formulae provide a way of relating the geometry of surfaces to entanglement entropy. A first-order bulk quantum correction to HRT was derived by Faulkner, Lewkowycz and Maldacena. This formula is generalized to include perturbative quantum corrections in the bulk at any (finite) order. Hurdles to spacetime emergence from entanglement entropy as described by HRT and its quantum

  18. A Causal Theory of Mnemonic Confabulation

    Directory of Open Access Journals (Sweden)

    Sven Bernecker

    2017-07-01

    Full Text Available This paper attempts to answer the question of what defines mnemonic confabulation vis-à-vis genuine memory. The two extant accounts of mnemonic confabulation as “false memory” and as ill-grounded memory are shown to be problematic, for they cannot account for the possibility of veridical confabulation, ill-grounded memory, and well-grounded confabulation. This paper argues that the defining characteristic of mnemonic confabulation is that it lacks the appropriate causal history. In the confabulation case, there is no proper counterfactual dependence of the state of seeming to remember on the corresponding past representation.

  19. De Broglie's causal interpretations of quantum mechanics

    International Nuclear Information System (INIS)

    Ben-Dov, Y.

    1989-01-01

    In this article we trace the history of de Broglie's two causal interpretations of quantum mechanics, namely the double solution and the pilot wave theories, at the two periods in which he developed them: 1924-27 and 1952 onwards. Examining the reasons for which he always preferred the first theory to the second, reasons that are mainly concerned with the question of the physical nature of the quantum wave function, we try to show the continuity and the coherence of his underlying vision

  20. On asymmetric causal relationships in Petropolitics

    Directory of Open Access Journals (Sweden)

    Balan Feyza

    2016-01-01

    Full Text Available The aim of this paper is to examine whether the First Law of Petropolitics denominated by Friedman in 2006 is valid for OPEC countries. To do this, this paper analyses the relationship between political risk and oil supply by applying the asymmetric panel causality test suggested by Hatemi-J (2011 to these countries for the period 1984-2014. The results show that the First Law of Petropolitics is valid for Angola, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, and the UAE, given that positive oil supply shocks significantly lead to negative political stability shocks, and negative oil supply shocks significantly lead to positive shocks in political stability.

  1. Conditional Granger Causality of Diffusion Processes

    Czech Academy of Sciences Publication Activity Database

    Wahl, B.; Feudel, U.; Hlinka, Jaroslav; Wächter, M.; Peinke, J.; Freund, J.A.

    2017-01-01

    Roč. 90, č. 10 (2017), č. článku 197. ISSN 1434-6028 R&D Projects: GA ČR GA13-23940S; GA MZd(CZ) NV15-29835A Institutional support: RVO:67985807 Keywords : Granger causality * stochastic process * diffusion process * nonlinear dynamical systems Subject RIV: BB - Applied Statistics, Operational Research OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 1.461, year: 2016

  2. 42 CFR 73.4 - Overlap select agents and toxins.

    Science.gov (United States)

    2010-10-01

    ... genetically modified. (d) Overlap select agents or toxins that meet any of the following criteria are excluded... Equine Encephalitis virus (c) Genetic Elements, Recombinant Nucleic Acids, and Recombinant Organisms: (1...

  3. Isolation of avian influenza virus in Texas.

    Science.gov (United States)

    Glass, S E; Naqi, S A; Grumbles, L C

    1981-01-01

    An avian influenza virus with surface antigens similar to those of fowl plague virus (Hav 1 Nav 2) was isolated in 1979 from 2 commercial turkey flocks in Central Texas. Two flocks in contact with these infected flocks developed clinical signs, gross lesions, and seroconversion but yielded no virus. This was the first recorded incidence of clinical avian influenza in Texas turkeys and only the second time that an agent with these surface antigens was isolated from turkeys in U.S.

  4. Trading Agents

    CERN Document Server

    Wellman, Michael

    2011-01-01

    Automated trading in electronic markets is one of the most common and consequential applications of autonomous software agents. Design of effective trading strategies requires thorough understanding of how market mechanisms operate, and appreciation of strategic issues that commonly manifest in trading scenarios. Drawing on research in auction theory and artificial intelligence, this book presents core principles of strategic reasoning that apply to market situations. The author illustrates trading strategy choices through examples of concrete market environments, such as eBay, as well as abst

  5. Indicators of causal agency in physical interactions: the role of the prior context.

    Science.gov (United States)

    Mayrhofer, Ralf; Waldmann, Michael R

    2014-09-01

    The question how agent and patient roles are assigned to causal participants has largely been neglected in the psychological literature on force dynamics. Inspired by the linguistic theory of Dowty (1991), we propose that agency attributions are based on a prototype concept of human intervention. We predicted that the number of criteria a participant in a causal interaction shares with this prototype determines the strength of agency intuitions. We showed in two experiments using versions of Michotte's (1963) launching scenarios that agency intuitions were moderated by manipulations of the context prior to the launching event. Altering features, such as relative movement, sequence of visibility, and self-propelled motion, tended to increase agency attributions to the participant that is normally viewed as patient in the standard scenario. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Isolation and Characterization of Encephalomyocarditis Virus from Dogs in China

    NARCIS (Netherlands)

    Luo, Ya-Kun; Liang, Lin; Tang, Qing-Hai; Zhou, Ling; Shi, Li-Jun; Cong, Ying-Ying; Lin, Wen-Cheng; Cui, Shang-Jin

    2017-01-01

    Encephalomyocarditis virus (EMCV) is as a potential zoonotic agent with a wide host range. Here, we describe an EMC virus isolate, identified as EMCV C15, which was successfully obtained from the serum of dogs from animal hospitals. Virus production in cell culture was confirmed by EMCV-specific

  7. Small round structured viruses (SRSVs) and transmission electron ...

    African Journals Online (AJOL)

    Administrator

    immune-electron microscopy (IEM) from patients' feces. They reported this virus particle as the causative agent of winter vomiting outbreaks in Norwalk (Kapikian et al.,. 1972). This is the remarkable landmark study of non- bacterial gastroenteritis viruses, especially for small round structured viruses (SRSVs). After that, many.

  8. Foundational perspectives on causality in large-scale brain networks

    Science.gov (United States)

    Mannino, Michael; Bressler, Steven L.

    2015-12-01

    A profusion of recent work in cognitive neuroscience has been concerned with the endeavor to uncover causal influences in large-scale brain networks. However, despite the fact that many papers give a nod to the important theoretical challenges posed by the concept of causality, this explosion of research has generally not been accompanied by a rigorous conceptual analysis of the nature of causality in the brain. This review provides both a descriptive and prescriptive account of the nature of causality as found within and between large-scale brain networks. In short, it seeks to clarify the concept of causality in large-scale brain networks both philosophically and scientifically. This is accomplished by briefly reviewing the rich philosophical history of work on causality, especially focusing on contributions by David Hume, Immanuel Kant, Bertrand Russell, and Christopher Hitchcock. We go on to discuss the impact that various interpretations of modern physics have had on our understanding of causality. Throughout all this, a central focus is the distinction between theories of deterministic causality (DC), whereby causes uniquely determine their effects, and probabilistic causality (PC), whereby causes change the probability of occurrence of their effects. We argue that, given the topological complexity of its large-scale connectivity, the brain should be considered as a complex system and its causal influences treated as probabilistic in nature. We conclude that PC is well suited for explaining causality in the brain for three reasons: (1) brain causality is often mutual; (2) connectional convergence dictates that only rarely is the activity of one neuronal population uniquely determined by another one; and (3) the causal influences exerted between neuronal populations may not have observable effects. A number of different techniques are currently available to characterize causal influence in the brain. Typically, these techniques quantify the statistical

  9. Chikungunya virus

    Science.gov (United States)

    Chikungunya virus infection; Chikungunya ... Where Chikungunya is Found Before 2013, the virus was found in Africa, Asia, Europe, and the Indian and Pacific oceans. In late 2013, outbreaks occurred for the first time in the ...

  10. Zika Virus

    Science.gov (United States)

    ... through blood transfusions. There have been outbreaks of Zika virus in the United States, Africa, Southeast Asia, the ... not travel to areas where there is a Zika virus outbreak. If you do decide to travel, first ...

  11. Zika Virus

    Science.gov (United States)

    ... Funding CDC Activities For Healthcare Providers Clinical Evaluation & Disease Sexual Transmission HIV Infection & Zika Virus Testing for Zika Test Specimens – At Time of Birth Diagnostic Tests Understanding Zika Virus Test Results ...

  12. ¿CONFIEREN PODERES CAUSALES LOS UNIVERSALES TRASCENDENTES?

    Directory of Open Access Journals (Sweden)

    José Tomás Alvarado Marambio

    2013-11-01

    Full Text Available This work discusses the so-called ‘Eleatic’ argument against the existence of transcendent universals, i. e. universals which does not require instantiation for its existence. The Eleatic Principle states that everything produces a difference in the causal powers of something. As transcendent universals seem not to produce such a difference, transcendent universals seem not to exist. The argument depends crucially on the justification and the interpretation of the Eleatic Principle. It is argued, first, that it is not very clear that the principle is justified, and, second, that there are several alternatives for its interpretation, in relation with the different theories one can endorse about modality or causality. Anti-realist theories of modality or causality are not very appropriate for the understanding of what should be a ‘causal power’. Neither does a realist theory of causality conjoined with a combinatorial theory of possible worlds. A ‘causal power’ seems to be better understood in connection with a realist –non-reductionist– theory of causality and a causal theory of modality. Taken in this way the Eleatic Principle, nonetheless, it is argued that transcendent universals do ‘produce’ a difference in causal powers, for every causal connection requires such universals for its existence.

  13. Are bruxism and the bite causally related?

    Science.gov (United States)

    Lobbezoo, F; Ahlberg, J; Manfredini, D; Winocur, E

    2012-07-01

    In the dental profession, the belief that bruxism and dental (mal-)occlusion ('the bite') are causally related is widespread. The aim of this review was to critically assess the available literature on this topic. A PubMed search of the English-language literature, using the query 'Bruxism [Majr] AND (Dental Occlusion [Majr] OR Malocclusion [Majr])', yielded 93 articles, of which 46 papers were finally included in the present review*. Part of the included publications dealt with the possible associations between bruxism and aspects of occlusion, from which it was concluded that neither for occlusal interferences nor for factors related to the anatomy of the oro-facial skeleton, there is any evidence available that they are involved in the aetiology of bruxism. Instead, there is a growing awareness of other factors (viz. psychosocial and behavioural ones) being important in the aetiology of bruxism. Another part of the included papers assessed the possible mediating role of occlusion between bruxism and its purported consequences (e.g. tooth wear, loss of periodontal tissues, and temporomandibular pain and dysfunction). Even though most dentists agree that bruxism may have several adverse effects on the masticatory system, for none of these purported adverse effects, evidence for a mediating role of occlusion and articulation has been found to date. Hence, based on this review, it should be concluded that to date, there is no evidence whatsoever for a causal relationship between bruxism and the bite. © 2012 Blackwell Publishing Ltd.

  14. Diagnostic reasoning using qualitative causal models

    International Nuclear Information System (INIS)

    Sudduth, A.L.

    1992-01-01

    The application of expert systems to reasoning problems involving real-time data from plant measurements has been a topic of much research, but few practical systems have been deployed. One obstacle to wider use of expert systems in applications involving real-time data is the lack of adequate knowledge representation methodologies for dynamic processes. Knowledge bases composed mainly of rules have disadvantages when applied to dynamic processes and real-time data. This paper describes a methodology for the development of qualitative causal models that can be used as knowledge bases for reasoning about process dynamic behavior. These models provide a systematic method for knowledge base construction, considerably reducing the engineering effort required. They also offer much better opportunities for verification and validation of the knowledge base, thus increasing the possibility of the application of expert systems to reasoning about mission critical systems. Starting with the Signed Directed Graph (SDG) method that has been successfully applied to describe the behavior of diverse dynamic processes, the paper shows how certain non-physical behaviors that result from abstraction may be eliminated by applying causal constraint to the models. The resulting Extended Signed Directed Graph (ESDG) may then be compiled to produce a model for use in process fault diagnosis. This model based reasoning methodology is used in the MOBIAS system being developed by Duke Power Company under EPRI sponsorship. 15 refs., 4 figs

  15. Introducing mechanics by tapping core causal knowledge

    International Nuclear Information System (INIS)

    Klaassen, Kees; Westra, Axel; Emmett, Katrina; Eijkelhof, Harrie; Lijnse, Piet

    2008-01-01

    This article concerns an outline of an introductory mechanics course. It is based on the argument that various uses of the concept of force (e.g. from Kepler, Newton and everyday life) share an explanatory strategy based on core causal knowledge. The strategy consists of (a) the idea that a force causes a deviation from how an object would move of its own accord (i.e. its force-free motion), and (b) an incentive to search, where the motion deviates from the assumed force-free motion, for recurring configurations with which such deviations can be correlated (interaction theory). Various assumptions can be made concerning both the force-free motion and the interaction theory, thus giving rise to a variety of specific explanations. Kepler's semi-implicit intuition about the force-free motion is rest, Newton's explicit assumption is uniform rectilinear motion, while in everyday explanations a diversity of pragmatic suggestions can be recognized. The idea is that the explanatory strategy, once made explicit by drawing on students' intuitive causal knowledge, can be made to function for students as an advance organizer, in the sense of a general scheme that they recognize but do not yet know how to detail for scientific purposes

  16. Causal Inference in the Perception of Verticality.

    Science.gov (United States)

    de Winkel, Ksander N; Katliar, Mikhail; Diers, Daniel; Bülthoff, Heinrich H

    2018-04-03

    The perceptual upright is thought to be constructed by the central nervous system (CNS) as a vector sum; by combining estimates on the upright provided by the visual system and the body's inertial sensors with prior knowledge that upright is usually above the head. Recent findings furthermore show that the weighting of the respective sensory signals is proportional to their reliability, consistent with a Bayesian interpretation of a vector sum (Forced Fusion, FF). However, violations of FF have also been reported, suggesting that the CNS may rely on a single sensory system (Cue Capture, CC), or choose to process sensory signals based on inferred signal causality (Causal Inference, CI). We developed a novel alternative-reality system to manipulate visual and physical tilt independently. We tasked participants (n = 36) to indicate the perceived upright for various (in-)congruent combinations of visual-inertial stimuli, and compared models based on their agreement with the data. The results favor the CI model over FF, although this effect became unambiguous only for large discrepancies (±60°). We conclude that the notion of a vector sum does not provide a comprehensive explanation of the perception of the upright, and that CI offers a better alternative.

  17. Quantum causality conceptual issues in the causal theory of quantum mechanics

    CERN Document Server

    Riggs, Peter J; French, Steven RD

    2009-01-01

    This is a treatise devoted to the foundations of quantum physics and the role that causality plays in the microscopic world governed by the laws of quantum mechanics. The book is controversial and will engender some lively debate on the various issues raised.

  18. Links between causal effects and causal association for surrogacy evaluation in a gaussian setting.

    Science.gov (United States)

    Conlon, Anna; Taylor, Jeremy; Li, Yun; Diaz-Ordaz, Karla; Elliott, Michael

    2017-11-30

    Two paradigms for the evaluation of surrogate markers in randomized clinical trials have been proposed: the causal effects paradigm and the causal association paradigm. Each of these paradigms rely on assumptions that must be made to proceed with estimation and to validate a candidate surrogate marker (S) for the true outcome of interest (T). We consider the setting in which S and T are Gaussian and are generated from structural models that include an unobserved confounder. Under the assumed structural models, we relate the quantities used to evaluate surrogacy within both the causal effects and causal association frameworks. We review some of the common assumptions made to aid in estimating these quantities and show that assumptions made within one framework can imply strong assumptions within the alternative framework. We demonstrate that there is a similarity, but not exact correspondence between the quantities used to evaluate surrogacy within each framework, and show that the conditions for identifiability of the surrogacy parameters are different from the conditions, which lead to a correspondence of these quantities. Copyright © 2017 John Wiley & Sons, Ltd.

  19. Causal inference in nonlinear systems: Granger causality versus time-delayed mutual information

    Science.gov (United States)

    Li, Songting; Xiao, Yanyang; Zhou, Douglas; Cai, David

    2018-05-01

    The Granger causality (GC) analysis has been extensively applied to infer causal interactions in dynamical systems arising from economy and finance, physics, bioinformatics, neuroscience, social science, and many other fields. In the presence of potential nonlinearity in these systems, the validity of the GC analysis in general is questionable. To illustrate this, here we first construct minimal nonlinear systems and show that the GC analysis fails to infer causal relations in these systems—it gives rise to all types of incorrect causal directions. In contrast, we show that the time-delayed mutual information (TDMI) analysis is able to successfully identify the direction of interactions underlying these nonlinear systems. We then apply both methods to neuroscience data collected from experiments and demonstrate that the TDMI analysis but not the GC analysis can identify the direction of interactions among neuronal signals. Our work exemplifies inference hazards in the GC analysis in nonlinear systems and suggests that the TDMI analysis can be an appropriate tool in such a case.

  20. Trivariate causality between economic growth, urbanisation and electricity consumption in Angola: Cointegration and causality analysis

    International Nuclear Information System (INIS)

    Solarin, Sakiru Adebola; Shahbaz, Muhammad

    2013-01-01

    This paper investigates the causal relationship between economic growth, urbanisation and electricity consumption in the case of Angola, while utilizing the data over the period of 1971–2009. We have applied Lee and Strazicich (2003. The Review of Economics and Statistics 63, 1082–1089; 2004. Working Paper. Department of Economics, Appalachian State University) unit root tests to examine the stationarity properties of the series. Using the Gregory–Hansen structural break cointegration procedure as a complement, we employ the ARDL bounds test to investigate long run relationships. The VECM Granger causality test is subsequently used to examine the direction of causality between economic growth, urbanisation, and electricity consumption. Our results indicate the existence of long run relationships. We further observe evidence in favour of bidirectional causality between electricity consumption and economic growth. The feedback hypothesis is also found between urbanisation and economic growth. Urbanisation and electricity consumption Granger cause each other. We conclude that Angola is energy-dependent country. Consequently, the relevant authorities should boost electricity production as one of the means of achieving sustainable economic development in the long run. - Highlights: • We consider the link between electricity consumption and economic growth in Angola. • Urbanisation is added to turn the research into a trivariate investigation. • Various time series procedures are used. • Results show that increasing electricity will improve economic growth in Angola. • Results show urbanisations reduced economic growth during civil war