2,980 research outputs found

    Entanglement reciprocation using three level atoms in a lambda configuration

    Full text link
    We propose a scheme in which entanglement can be transferred from atoms (discrete variables) to entangled states of cavity fields (continuous variables). The cavities play the role of a kind of quantum memory for entanglement, in such a way that it is possible to retrieve it back to the atoms. In our method, two three level atoms in a lambda configuration, previously entangled, are set to interact with single mode cavity fields prepared in coherent states. During the process, one e-bit of entanglement may be deposited in the cavities in an efficient way. We also show that the stored entanglement may be transferred back to flying atoms

    Reply to Itin, Obukhov and Hehl paper "An Electric Charge has no Screw Sense - A Comment on the Twist-Free Formulation of Electrodynamics by da Rocha & Rodrigues"

    Full text link
    In this note we briefly comment a paper by Itin, Obukhov and Hehl criticising our previous paper. We show that all remarks by our critics are ill conceived or irrelevant to our approach and moreover we provide some pertinent new comments to their critical paper, with the aim to clarify even more our view on the subject.Comment: This paper is a reply to arXiv:0911.5175 [physics.class-ph] which made some criticisms on our paper "Pair and Impar, Even and Odd Form Fields and Electromagnetism" arXiv:0811.1713 [math-ph] to appear in Annalen der Physik. A short version of our reply will also appear in Annalen de Physi

    New results for the two neutrino double beta decay in deformed nuclei with angular momentum projected basis

    Get PDF
    Four nuclei which are proved to be 2νββ2\nu\beta\beta emitters (76^{76}Ge, 82^{82}Se, 150^{150}Nd, 238^{238}U), and four suspected, due to the corresponding Q-values, to have this property (148^{148}Nd, 154^{154}Sm, 160^{160}Gd, 232^{232}Th), were treated within a proton-neutron quasiparticle random phase approximation (pnQRPA) with a projected spherical single particle basis. The advantage of the present procedure over the ones using a deformed Woods Saxon or Nilsson single particle basis is that the actual pnQRPA states have a definite angular momentum while all the others provide states having only K as a good quantum number. The model Hamiltonian involves a mean field term yielding the projected single particle states, a pairing interaction for alike nucleons and a dipole-dipole proton-neutron interaction in both the particle-hole (ph) and particle-particle (pp) channels. The effect of nuclear deformation on the single beta strength distribution as well as on the double beta Gamow-Teller transition amplitude (MGT_{{\rm GT}}) is analyzed. The results are compared with the existent data and with the results from a different approach, in terms of the process half life T1/2_{1/2}. The case of different deformations for mother and daughter nuclei is also presented.Comment: 45 pages, 13 figure

    Chronic intermittent hypoxia disrupts cardiorespiratory homeostasis and gut microbiota composition in adult male guinea-pigs

    Get PDF
    peer-reviewedBackground: Carotid body (peripheral oxygen sensor) sensitisation is pivotal in the development of chronic intermittent hypoxia (CIH)-induced hypertension. We sought to determine if exposure to CIH, modelling human sleep apnoea, adversely affects cardiorespiratory control in guinea-pigs, a species with hypoxia-insensitive carotid bodies. We reasoned that CIH-induced disruption of gut microbiota would evoke cardiorespiratory morbidity. Methods: Adult male guinea-pigs were exposed to CIH (6.5% O2 at nadir, 6 cycles.hour−1) for 8 h.day−1 for 12 consecutive days. Findings: CIH-exposed animals established reduced faecal microbiota species richness, with increased relative abundance of Bacteroidetes and reduced relative abundance of Firmicutes bacteria. Urinary corticosterone and noradrenaline levels were unchanged in CIH-exposed animals, but brainstem noradrenaline concentrations were lower compared with sham. Baseline ventilation was equivalent in CIH-exposed and sham animals; however, respiratory timing variability, sigh frequency and ventilation during hypoxic breathing were all lower in CIH-exposed animals. Baseline arterial blood pressure was unaffected by exposure to CIH, but β-adrenoceptor-dependent tachycardia and blunted bradycardia during phenylephrine-induced pressor responses was evident compared with sham controls. Interpretation: Increased carotid body chemo-afferent signalling appears obligatory for the development of CIH-induced hypertension and elevated chemoreflex control of breathing commonly reported in mammals, with hypoxia-sensitive carotid bodies. However, we reveal that exposure to modest CIH alters gut microbiota richness and composition, brainstem neurochemistry, and autonomic control of heart rate, independent of carotid body sensitisation, suggesting modulation of breathing and autonomic homeostasis via the microbiota-gut-brainstem axis. The findings have relevance to human sleep-disordered breathing

    Comparative Genomics of Cyanobacterial Symbionts Reveals Distinct, Specialized Metabolism in Tropical Dysideidae Sponges.

    Get PDF
    Marine sponges are recognized as valuable sources of bioactive metabolites and renowned as petri dishes of the sea, providing specialized niches for many symbiotic microorganisms. Sponges of the family Dysideidae are well documented to be chemically talented, often containing high levels of polyhalogenated compounds, terpenoids, peptides, and other classes of bioactive small molecules. This group of tropical sponges hosts a high abundance of an uncultured filamentous cyanobacterium, Hormoscilla spongeliae Here, we report the comparative genomic analyses of two phylogenetically distinct Hormoscilla populations, which reveal shared deficiencies in essential pathways, hinting at possible reasons for their uncultivable status, as well as differing biosynthetic machinery for the production of specialized metabolites. One symbiont population contains clustered genes for expanded polybrominated diphenylether (PBDE) biosynthesis, while the other instead harbors a unique gene cluster for the biosynthesis of the dysinosin nonribosomal peptides. The hybrid sequencing and assembly approach utilized here allows, for the first time, a comprehensive look into the genomes of these elusive sponge symbionts.IMPORTANCE Natural products provide the inspiration for most clinical drugs. With the rise in antibiotic resistance, it is imperative to discover new sources of chemical diversity. Bacteria living in symbiosis with marine invertebrates have emerged as an untapped source of natural chemistry. While symbiotic bacteria are often recalcitrant to growth in the lab, advances in metagenomic sequencing and assembly now make it possible to access their genetic blueprint. A cell enrichment procedure, combined with a hybrid sequencing and assembly approach, enabled detailed genomic analysis of uncultivated cyanobacterial symbiont populations in two chemically rich tropical marine sponges. These population genomes reveal a wealth of secondary metabolism potential as well as possible reasons for historical difficulties in their cultivation

    Role of Sterile Neutrino Warm Dark Matter in Rhenium and Tritium Beta Decays

    Full text link
    Sterile neutrinos with mass in the range of one to a few keV are important as extensions of the Standard Model of particle physics and are serious dark matter (DM) candidates. This DM mass scale (warm DM) is in agreement with both cosmological and galactic observations. We study the role of a keV sterile neutrino through its mixing with a light active neutrino in Rhenium 187 and Tritium beta decays. We pinpoint the energy spectrum of the beta particle, 0 < T_e < (Q_{beta} - m_s), as the region where a sterile neutrino could be detected and where its mass m_s could be measured. This energy region is at least 1 keV away rom the region suitable to measure the mass of the light active neutrino, located near the endpoint Q_{beta} . The emission of a keV sterile neutrino in a beta decay could show up as a small kink in the spectrum of the emitted beta particle. With this in view, we perform a careful calculation of the Rhenium and Tritium beta spectra and estimate the size of this perturbation by means of the dimensionless ratio R of the sterile neutrino to the active neutrino contributions. We comment on the possibility of searching for sterile neutrino signatures in two experiments which are currently running at present, MARE and KATRIN, focused on the Rhenium 187 and Tritium beta decays respectively.Comment: 16 pages, 10 figures. Version to appear in Nucl. Phys. B. Results and conclusions unchange

    Effective Lagrangian Approach to pion photoproduction from the nucleon

    Full text link
    We present a pion photoproduction model on the free nucleon based on an Effective Lagrangian Approach (ELA) which includes the nucleon resonances (Δ(1232)\Delta(1232), N(1440), N(1520), N(1535), Δ(1620)\Delta (1620), N(1650), and Δ(1700)\Delta (1700)), in addition to Born and vector meson exchange terms. The model incorporates a new theoretical treatment of spin-3/2 resonances, first introduced by Pascalutsa, avoiding pathologies present in previous models. Other main features of the model are chiral symmetry, gauge invariance, and crossing symmetry. We use the model combined with modern optimization techniques to assess the parameters of the nucleon resonances on the basis of world data on electromagnetic multipoles. We present results for electromagnetic multipoles, differential cross sections, asymmetries, and total cross sections for all one pion photoproduction processes on free nucleons. We find overall agreement with data from threshold up to 1 GeV in laboratory frame.Comment: Misprints corrected. 60 pages. 33 figures.5 tables. Accepted for publication in Annals of Physics (NY

    Assessing and augmenting SCADA cyber security: a survey of techniques

    Get PDF
    SCADA systems monitor and control critical infrastructures of national importance such as power generation and distribution, water supply, transportation networks, and manufacturing facilities. The pervasiveness, miniaturisations and declining costs of internet connectivity have transformed these systems from strictly isolated to highly interconnected networks. The connectivity provides immense benefits such as reliability, scalability and remote connectivity, but at the same time exposes an otherwise isolated and secure system, to global cyber security threats. This inevitable transformation to highly connected systems thus necessitates effective security safeguards to be in place as any compromise or downtime of SCADA systems can have severe economic, safety and security ramifications. One way to ensure vital asset protection is to adopt a viewpoint similar to an attacker to determine weaknesses and loopholes in defences. Such mind sets help to identify and fix potential breaches before their exploitation. This paper surveys tools and techniques to uncover SCADA system vulnerabilities. A comprehensive review of the selected approaches is provided along with their applicability

    A Recombinant Potato virus Y Infectious Clone Tagged with the Rosea1 Visual Marker (PVY-Ros1) Facilitates the Analysis of Viral Infectivity and Allows the Production of Large Amounts of Anthocyanins in Plants

    Get PDF
    "This Document is Protected by copyright and was first published by Frontiers. All rights reserved. It is reproduced with permission."[EN] Potato virus Y (PVY) is a major threat to the cultivation of potato and other solanaceous plants. By inserting a cDNA coding for the Antirrhinum majus Rosea1 transcription factor into a PVY infectious clone, we created a biotechnological tool (PVY-Ros1) that allows infection by this relevant plant virus to be tracked by the naked eye with no need for complex instrumentation. Rosea1 is an MYB-type transcription factor whose expression activates the biosynthesis of anthocyanin pigments in a dose-specific and cell-autonomous manner. Our experiments showed that the mechanical inoculation of solanaceous plants with PVY-Ros1 induced the formation of red infection foci in inoculated tissue and solid dark red pigmentation in systemically infected tissue, which allows disease progression to be easily monitored. By using silver nanoparticles, a nanomaterial with exciting antimicrobial properties, we proved the benefits of PVY-Ros1 to analyze novel antiviral treatments in plants. PVY-Ros1 was also helpful for visually monitoring the virus transmission process by an aphid vector. Most importantly, the anthocyanin analysis of infected tobacco tissues demonstrated that PVY-Ros1 is an excellent biotechnological tool for molecular farming because it induces the accumulation of larger amounts of anthocyanins, antioxidant compounds of nutritional, pharmaceutical and industrial interest, than those that naturally accumulate in some fruits and vegetables well known for their high anthocyanin content. Hence these results support the notion that the virus-mediated expression of regulatory factors and enzymes in plants facilitates easy quick plant metabolism engineering.This research was supported by grants BIO2014-54269-R and AGL2013-49919-EXP to J-AD and AGL2013-42537-R to J-JL-M from the Ministerio de Economia y Competitividad (MINECO, co-financed FEDER funds), Spain. MM was supported by the Erasmus Mundus Scholarship-ACTION 2 WELCOME program of the European Commission. Research in CRAG is supported in part by CERCA (Generalitat de Catalunya) and by "Severo Ochoa Programme for Centres of Excellence in R&D" 2016-2019 (SEV-2015-0533).Cordero, T.; Mohamed, M.; Lopez Moya, J.; Daros Arnau, JA. (2017). A Recombinant Potato virus Y Infectious Clone Tagged with the Rosea1 Visual Marker (PVY-Ros1) Facilitates the Analysis of Viral Infectivity and Allows the Production of Large Amounts of Anthocyanins in Plants. Frontiers in Microbiology. 8:1-11. https://doi.org/10.3389/fmicb.2017.00611S1118Abdel-Hafez, S. I. I., Nafady, N. A., Abdel-Rahim, I. R., Shaltout, A. M., Daròs, J.-A., & Mohamed, M. A. (2016). Assessment of protein silver nanoparticles toxicity against pathogenic Alternaria solani. 3 Biotech, 6(2). doi:10.1007/s13205-016-0515-6Allan, A. C., Hellens, R. P., & Laing, W. A. (2008). MYB transcription factors that colour our fruit. Trends in Plant Science, 13(3), 99-102. doi:10.1016/j.tplants.2007.11.012An, C. H., Lee, K.-W., Lee, S.-H., Jeong, Y. J., Woo, S. G., Chun, H., … Kim, C. Y. (2015). Heterologous expression of IbMYB1a by different promoters exhibits different patterns of anthocyanin accumulation in tobacco. Plant Physiology and Biochemistry, 89, 1-10. doi:10.1016/j.plaphy.2015.02.002Atreya, P. L., Lopez-Moya, J. J., Chu, M., Atreya, C. D., & Pirone, T. P. (1995). Mutational analysis of the coat protein N-terminal amino acids involved in potyvirus transmission by aphids. Journal of General Virology, 76(2), 265-270. doi:10.1099/0022-1317-76-2-265Baulcombe, D. C., Chapman, S., & Cruz, S. (1995). Jellyfish green fluorescent protein as a reporter for virus infections. The Plant Journal, 7(6), 1045-1053. doi:10.1046/j.1365-313x.1995.07061045.xBedoya, L., Martínez, F., Rubio, L., & Daròs, J.-A. (2010). Simultaneous equimolar expression of multiple proteins in plants from a disarmed potyvirus vector. Journal of Biotechnology, 150(2), 268-275. doi:10.1016/j.jbiotec.2010.08.006Bedoya, L. C., & Daròs, J.-A. (2010). Stability of Tobacco etch virus infectious clones in plasmid vectors. Virus Research, 149(2), 234-240. doi:10.1016/j.virusres.2010.02.004Bedoya, L. C., Martínez, F., Orzáez, D., & Daròs, J.-A. (2012). Visual Tracking of Plant Virus Infection and Movement Using a Reporter MYB Transcription Factor That Activates Anthocyanin Biosynthesis. Plant Physiology, 158(3), 1130-1138. doi:10.1104/pp.111.192922Boyer, J.-C., & Haenni, A.-L. (1994). Infectious Transcripts and cDNA Clones of RNA Viruses. Virology, 198(2), 415-426. doi:10.1006/viro.1994.1053Chalfie, M., Tu, Y., Euskirchen, G., Ward, W., & Prasher, D. (1994). Green fluorescent protein as a marker for gene expression. Science, 263(5148), 802-805. doi:10.1126/science.8303295Cordero, T., Cerdán, L., Carbonell, A., Katsarou, K., Kalantidis, K., & Daròs, J.-A. (2017). Dicer-Like 4 Is Involved in Restricting the Systemic Movement of Zucchini yellow mosaic virus in Nicotiana benthamiana. Molecular Plant-Microbe Interactions®, 30(1), 63-71. doi:10.1094/mpmi-11-16-0239-rDolja, V. V., McBride, H. J., & Carrington, J. C. (1992). Tagging of plant potyvirus replication and movement by insertion of beta-glucuronidase into the viral polyprotein. Proceedings of the National Academy of Sciences, 89(21), 10208-10212. doi:10.1073/pnas.89.21.10208Elbeshehy, E. K. F., Elazzazy, A. M., & Aggelis, G. (2015). Silver nanoparticles synthesis mediated by new isolates of Bacillus spp., nanoparticle characterization and their activity against Bean Yellow Mosaic Virus and human pathogens. Frontiers in Microbiology, 6. doi:10.3389/fmicb.2015.00453Engler, C., & Marillonnet, S. (2013). Golden Gate Cloning. Methods in Molecular Biology, 119-131. doi:10.1007/978-1-62703-764-8_9FRENCH, R., JANDA, M., & AHLQUIST, P. (1986). Bacterial Gene Inserted in an Engineered RNA Virus: Efficient Expression in Monocotyledonous Plant Cells. Science, 231(4743), 1294-1297. doi:10.1126/science.231.4743.1294Gibbs, A., & Ohshima, K. (2010). Potyviruses and the Digital Revolution. Annual Review of Phytopathology, 48(1), 205-223. doi:10.1146/annurev-phyto-073009-114404Johansen, I. E. (1996). Intron insertion facilitates amplification of cloned virus cDNA in Escherichia coli while biological activity is reestablished after transcription in vivo. Proceedings of the National Academy of Sciences, 93(22), 12400-12405. doi:10.1073/pnas.93.22.12400Joshi, R. L., Joshi, V., & Ow, D. W. (1990). BSMV genome mediated expression of a foreign gene in dicot and monocot plant cells. The EMBO Journal, 9(9), 2663-2669. doi:10.1002/j.1460-2075.1990.tb07451.xKarasev, A. V., & Gray, S. M. (2013). Continuous and Emerging Challenges of Potato virus Y in Potato. Annual Review of Phytopathology, 51(1), 571-586. doi:10.1146/annurev-phyto-082712-102332Kelloniemi, J., Mäkinen, K., & Valkonen, J. P. T. (2008). Three heterologous proteins simultaneously expressed from a chimeric potyvirus: Infectivity, stability and the correlation of genome and virion lengths. Virus Research, 135(2), 282-291. doi:10.1016/j.virusres.2008.04.006Krenz, B., Bronikowski, A., Lu, X., Ziebell, H., Thompson, J. R., & Perry, K. L. (2015). Visual monitoring of Cucumber mosaic virus infection in Nicotiana benthamiana following transmission by the aphid vector Myzus persicae. Journal of General Virology, 96(9), 2904-2912. doi:10.1099/vir.0.000185Lara, H. H., Ixtepan-Turrent, L., Garza Treviño, E. N., & Singh, D. K. (2011). Use of silver nanoparticles increased inhibition of cell-associated HIV-1 infection by neutralizing antibodies developed against HIV-1 envelope proteins. Journal of Nanobiotechnology, 9(1), 38. doi:10.1186/1477-3155-9-38López-Moya, J. J., & Garcı́a, J. A. (2000). Construction of a stable and highly infectious intron-containing cDNA clone of plum pox potyvirus and its use to infect plants by particle bombardment. Virus Research, 68(2), 99-107. doi:10.1016/s0168-1702(00)00161-1Majer, E., Llorente, B., Rodríguez-Concepción, M., & Daròs, J.-A. (2017). Rewiring carotenoid biosynthesis in plants using a viral vector. Scientific Reports, 7(1). doi:10.1038/srep41645Marillonnet, S., Thoeringer, C., Kandzia, R., Klimyuk, V., & Gleba, Y. (2005). Systemic Agrobacterium tumefaciens–mediated transfection of viral replicons for efficient transient expression in plants. Nature Biotechnology, 23(6), 718-723. doi:10.1038/nbt1094Mishra, S., & Singh, H. B. (2014). Biosynthesized silver nanoparticles as a nanoweapon against phytopathogens: exploring their scope and potential in agriculture. Applied Microbiology and Biotechnology, 99(3), 1097-1107. doi:10.1007/s00253-014-6296-0Nie, B., Singh, M., Sullivan, A., Singh, R. P., Xie, C., & Nie, X. (2011). Recognition and Molecular Discrimination of Severe and Mild PVYO Variants of Potato virus Y in Potato in New Brunswick, Canada. Plant Disease, 95(2), 113-119. doi:10.1094/pdis-04-10-0257Olspert, A., Chung, B. Y., Atkins, J. F., Carr, J. P., & Firth, A. E. (2015). Transcriptional slippage in the positive‐sense RNA virus family Potyviridae. EMBO reports, 16(8), 995-1004. doi:10.15252/embr.201540509Passeri, V., Koes, R., & Quattrocchio, F. M. (2016). New Challenges for the Design of High Value Plant Products: Stabilization of Anthocyanins in Plant Vacuoles. Frontiers in Plant Science, 7. doi:10.3389/fpls.2016.00153Quenouille, J., Vassilakos, N., & Moury, B. (2013). Potato virus Y: a major crop pathogen that has provided major insights into the evolution of viral pathogenicity. Molecular Plant Pathology, 14(5), 439-452. doi:10.1111/mpp.12024Revers, F., & García, J. A. (2015). Molecular Biology of Potyviruses. Advances in Virus Research, 101-199. doi:10.1016/bs.aivir.2014.11.006Rodamilans, B., Valli, A., Mingot, A., San León, D., Baulcombe, D., López-Moya, J. J., & García, J. A. (2015). RNA Polymerase Slippage as a Mechanism for the Production of Frameshift Gene Products in Plant Viruses of the Potyviridae Family. Journal of Virology, 89(13), 6965-6967. doi:10.1128/jvi.00337-15Rodriguez, E. A., Campbell, R. E., Lin, J. Y., Lin, M. Z., Miyawaki, A., Palmer, A. E., … Tsien, R. Y. (2017). The Growing and Glowing Toolbox of Fluorescent and Photoactive Proteins. Trends in Biochemical Sciences, 42(2), 111-129. doi:10.1016/j.tibs.2016.09.010Rupar, M., Faurez, F., Tribodet, M., Gutiérrez-Aguirre, I., Delaunay, A., Glais, L., … Ravnikar, M. (2015). Fluorescently Tagged Potato virus Y: A Versatile Tool for Functional Analysis of Plant-Virus Interactions. Molecular Plant-Microbe Interactions®, 28(7), 739-750. doi:10.1094/mpmi-07-14-0218-taSaxena, P., Hsieh, Y.-C., Alvarado, V. Y., Sainsbury, F., Saunders, K., Lomonossoff, G. P., & Scholthof, H. B. (2010). Improved foreign gene expression in plants using a virus-encoded suppressor of RNA silencing modified to be developmentally harmless. Plant Biotechnology Journal, 9(6), 703-712. doi:10.1111/j.1467-7652.2010.00574.xSCHOLTHOF, K.-B. G., ADKINS, S., CZOSNEK, H., PALUKAITIS, P., JACQUOT, E., HOHN, T., … FOSTER, G. D. (2011). Top 10 plant viruses in molecular plant pathology. Molecular Plant Pathology, 12(9), 938-954. doi:10.1111/j.1364-3703.2011.00752.xThole, V., Worland, B., Snape, J. W., & Vain, P. (2007). The pCLEAN Dual Binary Vector System for Agrobacterium-Mediated Plant Transformation. Plant Physiology, 145(4), 1211-1219. doi:10.1104/pp.107.108563Tilsner, J., & Oparka, K. J. (2010). Tracking the green invaders: advances in imaging virus infection in plants. Biochemical Journal, 430(1), 21-37. doi:10.1042/bj20100372Zhang, Y., Butelli, E., & Martin, C. (2014). Engineering anthocyanin biosynthesis in plants. Current Opinion in Plant Biology, 19, 81-90. doi:10.1016/j.pbi.2014.05.011Zhao, X., Yuan, Z., Fang, Y., Yin, Y., & Feng, L. (2012). Characterization and evaluation of major anthocyanins in pomegranate (Punica granatum L.) peel of different cultivars and their development phases. European Food Research and Technology, 236(1), 109-117. doi:10.1007/s00217-012-1869-
    corecore