Articles de revues : « PeV region »

1

Tolchkov, Eugene V., Vanya I. Rasheva, Silvia Bonaccorsi, Thomas Westphal et Vladimir A. Gvozdev. « The Size and Internal Structure of a Heterochromatic Block Determine Its Ability to Induce Position Effect Variegation in Drosophila melanogaster ». Genetics 154, n^o 4 (1 avril 2000) : 1611–26. http://dx.doi.org/10.1093/genetics/154.4.1611.

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Abstract In the In(1LR)pn2a rearrangement, the 1A-2E euchromatic segment is transposed to the vicinity of X heterochromatin (Xh), resulting in position effect variegation (PEV) of the genes in the 2BE region. Practically the whole X-linked heterochromatin is situated adjacent to variegated euchromatic genes. Secondary rearrangements showing weakening or reversion of PEV were obtained by irradiation of the In(1LR)pn2a. These rearrangements demonstrate a positive correlation between the strength of PEV of the wapl locus and the sizes of the adjacent heterochromatic blocks carrying the centromere. The smallest PEV-inducing fragment consists of a block corresponding to ~10% of Xh and containing the entire XR, the centromere, and a very proximal portion of XL heterochromatin. Heterochromatic blocks retaining the entire XR near the 2E region, but lacking the centromere, show no PEV. Reversion of PEV was also observed as a result of an internal rearrangement of the Xh blocks where the centromere is moved away from the eu-heterochromatin boundary but the amount of X heterochromatin remaining adjacent to 2E is unchanged. We propose a primary role of the X pericentromeric region in PEV induction and an enhancing effect of the other blocks, positively correlated with their size.

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Kaku, Yoshihiro, Akinori Sarai et Yosuke Murakami. « Genetic reclassification of porcine enteroviruses ». Journal of General Virology 82, n^o 2 (1 février 2001) : 417–24. http://dx.doi.org/10.1099/0022-1317-82-2-417.

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The genetic diversity of porcine teschoviruses (PTVs; previously named porcine enterovirus 1) and most serotypes of porcine enteroviruses (PEVs) was studied. Following the determination of the major portion of the genomic sequence of PTV reference strain Talfan, the nucleotide and derived amino acid sequences of the RNA-dependent RNA polymerase (RdRp) region, the capsid VP2 region and the 3′ non-translated region (3′-NTR) were compared among PTVs and PEVs and with other picornaviruses. The sequences were obtained by RT–PCR and 3′-RACE with primers based on the sequences of Talfan and available PEV strains. Phylogenetic analysis of RdRp/VP2 and analysis of the predicted RNA secondary structure of the 3′-NTR indicated that PEVs should be reclassified genetically into at least three groups, one that should be assigned to PTVs and two PEV subspecies represented by strain PEV-8 V13 and strain PEV-9 UKG410/73.

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Clegg, N. J., I. P. Whitehead, J. K. Brock, D. A. Sinclair, R. Mottus, G. Stromotich, M. J. Harrington et T. A. Grigliatti. « A cytogenetic analysis of chromosomal region 31 of Drosophila melanogaster. » Genetics 134, n^o 1 (1 mai 1993) : 221–30. http://dx.doi.org/10.1093/genetics/134.1.221.

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Abstract Cytogenetic region 31 of the second chromosome of Drosophila melanogaster was screened for recessive lethal mutations. One hundred and thirty nine new recessive lethal alleles were isolated that fail to complement Df(2L)J2 (31A-32A). These new alleles, combined with preexisting mutations in the region, define 52 complementation groups, 35 of which have not previously been described. Among the new mutations were alleles of the cdc2 and mfs(2)31 genes. Six new deficiencies were also isolated and characterized identifying 16 deficiency subintervals within region 31. The new deficiencies were used to further localize three loci believed to encode non-histone chromosomal proteins. Suvar(2)1/Su(var)214, a dominant suppressor of position-effect variegation (PEV), maps to 31A-B, while the recessive suppressors of PEV mfs(2)31 and wdl were localized to regions 31E and 31F-32A, respectively. In addition, the cytological position of several mutations that interact with heterochromatin were more precisely defined.

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Erlykin, A. D., et A. W. Wolfendale. « Spectral features and masses in the PeV region ». Nuclear Physics B - Proceedings Supplements 122 (juillet 2003) : 209–12. http://dx.doi.org/10.1016/s0920-5632(03)80380-8.

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Sabl, Joy F., et Steven Henikoff. « Copy Number and Orientation Determine the Susceptibility of a Gene to Silencing by Nearby Heterochromatin in Drosophila ». Genetics 142, n^o 2 (1 février 1996) : 447–58. http://dx.doi.org/10.1093/genetics/142.2.447.

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Abstract The classical phenomenon of position-effect variegation (PEV) is the mosaic expression that occurs when a chromosomal rearrangement moves a euchromatic gene near heterochromatin. A striking feature of this phenomenon is that genes far away from the junction with heterochromatin can be affected, as if the heterochromatic state “spreads.” We have investigated classical PEV of a Drosophila brown transgene affected by a heterochromatic junction ~60 kb away. PEV was enhanced when the transgene was locally duplicated using P transposase. Successive rounds of P transposase mutagenesis and phenotypic selection produced a series of PEV alleles with differences in phenotype that depended on transgene copy number and orientation. As for other examples of classical PEV, nearby heterochromatin was required for gene silencing. Modifications of classical PEV by alterations at a single site are unexpected, and these observations contradict models for spreading that invoke propagation of heterochromatin along the chromosome. Rather, our results support a model in which local alterations affect the affinity of a gene region for nearby heterochromatin via homology-based pairing, suggesting an alternative explanation for this 65-year-old phenomenon.

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Adriani, Oscar, et Lorenzo Pacini. « Results from high energy direct measurements and future prospects ». EPJ Web of Conferences 283 (2023) : 02001. http://dx.doi.org/10.1051/epjconf/202328302001.

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In this contribution a review of the recent results from high energy cosmic ray measurements, in the ’above TeV’ energy regions, will be presented. The future experiments that will be realised to significantly improve the current measurements, aiming to explore the PeV region with direct measurements, will also be described.

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Sinclair, D. A., A. A. Ruddell, J. K. Brock, N. J. Clegg, V. K. Lloyd et T. A. Grigliatti. « A cytogenetic and genetic characterization of a group of closely linked second chromosome mutations that suppress position-effect variegation in Drosophila melanogaster. » Genetics 130, n^o 2 (1 février 1992) : 333–44. http://dx.doi.org/10.1093/genetics/130.2.333.

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Abstract Characterization of a group of dominant second chromosome suppressor of position-effect variegation (PEV) (Su(var)) mutants has revealed a variety of interesting properties, including: maternal-effect suppression of PEV, homozygous lethality or semilethality and male-specific hemizygous lethality, female infecundity, acute sensitivity to the amount of heterochromatin in the cell and sensitivity to sodium butyrate. Deficiency/duplication mapping and complementation tests have revealed that eight of the mutants define at least two genes in section 31 of the left arm of chromosome 2 and they suggest that a ninth corresponds to an additional nonessential Su(var) gene within or near this region. The effects of specific deficiencies and a duplication on PEV indicate that the expression of one or more of the Su(var) genes in this region of the chromosome is dose-dependent, i.e., capable of haplo-abnormal suppression and triplo-abnormal enhancement. Interestingly, the appearance of certain visible phenotypes among a subset of the mutants suggests that they may possess antimorphic properties. Our results are consistent with the hypothesis that two of these Su(var) genes encode structural components of heterochromatin. We also report that two previously isolated mutants located in 31E and 31F-32A act as recessive suppressors of PEV.

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Spofford, Janice B., et Rob DeSalle. « Nucleolus organizer-suppressed position-effect variegation in Drosophila melanogaster ». Genetical Research 57, n^o 3 (juin 1991) : 245–55. http://dx.doi.org/10.1017/s0016672300029396.

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SummaryThe white locus is inactivated in a cell-by-cell variegated pattern when juxtaposed with the proximal or distal parts of the nucleolus organizer region (NO) by X chromosome inversion. Recombinants for two such inversions, wm51b and wm4, were obtained and randomized for genetic background. White locus activity was much higher in the wm4 recombinant duplicated for most of the NO and much lower in the wm51b recombinant deficient for it. Although there may be other molecular differences between the heterochromatic regions of the recombinants, the most obvious is the dosage of NO. Suppression of a NO region-evoked variegated phenotype by additional NO doses is discussed in relation to four different classes of models for position-effect variegation (PEV): chromatin structure, nuclear geometry, incomplete transposition of mobile elements, and heterochromatin promoter-driven transcription. A corollary of the structural model is functional subdivision of heterochromatin, which would enable the use of PEV as a tool for its study.

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Habuka, Rie, Yuta Aizawa, Ryohei Izumita, Hisanori Domon, Yutaka Terao et Akihiko Saitoh. « 2853. Innate Immune Response in Serum and Cerebrospinal Fluid of Neonates and Infants Infected with Parechovirus-A3 and Enteroviruses ». Open Forum Infectious Diseases 6, Supplement_2 (octobre 2019) : S74. http://dx.doi.org/10.1093/ofid/ofz359.158.

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Abstract Background Parechovirus-A3 (PeV-A3) and enteroviruses (EVs) are the most common viral causes of neonatal and infantile sepsis. We previously reported that the clinical manifestations of PeV-A3 infection—e.g., high body temperature, tachycardia, and poor peripheral circulation, but not cerebrospinal fluid (CSF) pleocytosis—tend be more severe than those of EV infection. We tested the hypothesis that innate immune responses to PeV-A3 and EVs are distinct. Methods Using serum and CSF samples, we investigated immune responses of febrile neonates and infants <4 months in Niigata, Japan, from 2015 through 2018. PeV-A and EV infections were diagnosed with real-time PCR. PeV-A3 infection was diagnosed by sequence analysis of the VP1 region. The control was clinically well patients without serum and CSF findings suggestive of bacterial or viral etiology. The Milliplex MAP human cytokine/chemokine magnetic bead panel (Merck Millipore, Germany) was used to analyze 22 cytokines/chemokines related to innate immunity in serum and CSF. Results We evaluated 14 PeV-A3-infected and 15 EV-infected patients and 8 controls. Serum levels of proinflammatory cytokines/chemokines (fractalkine, interferon-α2, interleukin [IL]-1 receptor α, IL-6, IL-8, and IL-15) were significantly higher in PeV-A3-infected patients than in EV-infected patients (P < 0.005). Serum cytokine/chemokine profiles of EV-infected patients did not differ from those of controls. However, while most pro- and anti-inflammatory cytokines/chemokines in CSF were elevated in EV-infected patients, levels were low or undetectable in PeV-A3-infected patients and controls (P < 0.005). Conclusion PeV-A3-infected patients had high serum levels of proinflammatory cytokines/chemokines, which may explain why clinical manifestations were more severe in this patient group than in EV-infected patients. Conversely, the limited or nonexistent innate immune response in CSF from PeV-A3-infected patients might explain the absence of CSF pleocytosis. These findings improve our understanding of the differing pathophysiological characteristics of PeV-A3 and EV infection in neonates and young infants. Disclosures All Authors: No reported Disclosures.

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Baksa, K., H. Morawietz, V. Dombrádi, M. Axton, H. Taubert, G. Szabó, I. Török, A. Udvardy, H. Gyurkovics et B. Szöör. « Mutations in the protein phosphatase 1 gene at 87B can differentially affect suppression of position-effect variegation and mitosis in Drosophila melanogaster. » Genetics 135, n^o 1 (1 septembre 1993) : 117–25. http://dx.doi.org/10.1093/genetics/135.1.117.

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Abstract The suppressor of position effect variegation (PEV) locus Su-var(3)6 maps to 87B5-10. The breakpoints of deficiencies that define this interval have been placed on a 250-kb molecular map of the region. The locus is allelic to the ck19 complementation group previously shown to encode a type 1 serine-threonine protein phosphatase (PP1) catalytic subunit. When introduced into flies by P element-mediated transformation, a 5.8-kb genomic fragment carrying this gene overcomes the suppressor phenotype of Su-var(3)6(01) and recessive lethality of all mutations of the locus. Four of the mutant alleles at the locus show a broad correlation between high levels of suppression of PEV, a high frequency of aberrant mitosis and low PP1 activity in larval extracts. However, some alleles with low PP1 activity show weak suppression of PEV with a high frequency of abnormal mitosis, whereas others show strong suppression of PEV with normal mitosis. The basis for these discussed.

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Balasov, M. L. « Genetic factors controlling white gene expression of the transposon AR4-24 at a telomere in Drosophila melanogaster ». Genome 45, n^o 6 (1 décembre 2002) : 1025–34. http://dx.doi.org/10.1139/g02-074.

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The position effect of the AR 4-24 P[white, rosy] transposon was studied at cytological position 60F. Three copies of the transposon (within ~50-kb region) resulted in a spatially restricted pattern of white variegation. This pattern was modified by temperature and by removal of the Y chromosome, suggesting that it was due to classical heterochromatin-induced position effect variegation (PEV). In contrast with classical PEV, extra dose of the heterochromatin protein 1 (HP1) suppressed white variegation and one dose enhanced it. The effect of Pc-G, trx-G, and other PEV suppressors was also tested. It was found that E(Pc)1, TrlR85, and mutations of Su(z)2C relieve AR 4-24- silencing and z1 enhances it. To explain the results obtained with these modifiers, it is proposed that PEV and telomeric position effect can counteract each other at this particular cytological site.Key words: position effect variegation, heterochromatin protein 1, Drosophila melanogaster.

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Lloyd, Vett K., Donald A. Sinclair et Thomas A. Grigliatti. « Competition Between Different Variegating Rearrangements for Limited Heterochromatic Factors in Drosophila melanogaster ». Genetics 145, n^o 4 (1 avril 1997) : 945–59. http://dx.doi.org/10.1093/genetics/145.4.945.

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Position effect variegation (PEV) results from the juxtaposition of a euchromatic gene to heterochromatin. In its new position the gene is inactivated in some cells and not in others. This mosaic expression is consistent with variability in the spread of heterochromatin from cell to cell. As many components of heterochromatin are likely to be produced in limited amounts, the spread of heterochromatin into a normally euchromatic region should be accompanied by a concomitant loss or redistribution of the protein components from other heterochromatic regions. We have shown that this is the case by simultaneously monitoring variegation of a euchromatic and a heterochromatic gene associated with a single chromosome rearrangement. Secondly, if several heterochromatic regions of the genome share limited components of heterochromatin, then some variegating rearrangements should compete for these components. We have examined this hypothesis by testing flies with combinations of two or more different variegating rearrangements. Of the nine combinations of pairs of variegating rearrangements we studied, seven showed nonreciprocal interactions. These results imply that many components of heterochromatin are both shared and present in limited amounts and that they can transfer between chromosomal sites. Consequently, even nonvariegation portions of the genome will be disrupted by re-allocation of heterochromatic proteins associated with PEV. These results have implications for models of PEV.

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Donaldson, Kathryn M., et Gary H. Karpen. « Trans-Suppression of Terminal Deficiency-Associated Position Effect Variegation in a Drosophila Minichromosome ». Genetics 145, n^o 2 (1 février 1997) : 325–37. http://dx.doi.org/10.1093/genetics/145.2.325.

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Position effect variegation (PEV) is the clonal inactivation of euchromatic or heterochromatic genes that are abnormally positioned within a chromosome. PEV can be influenced by modifiers in trans, including single gene mutations and the total amount of heterochromatin present in the genome. Terminal deletions of a Drosophila minichromosome (Dp1187) dramatically increase PEV of a yellow + body-color gene located in cis, even when the terminal break is >100 kb distal to the yellow gene. Here we demonstrate that terminal deficiency-associated PEV can be suppressed by the presence of a second minichromosome, a novel phenomenon termed “trans-suppression.” The chromosomal elements responsible for trans-suppression were investigated using a series of minichromosomes with molecularly characterized deletions and inversions. The data suggest that trans-suppression does not involve communication between transcriptional regulatory elements on the homologues, a type of transvection known to act at the yellow locus. Furthermore, trans-suppression is not accomplished by titration through the addition of extra centric heterochromatin, a general mechanism for PEV suppression. We demonstrate that trans-suppression is disrupted by significant changes in the structure of the suppressing minichromosome, including deletions of the yellow region and centric heterochromatin, and large inversions of the centric heterochromatin. We conclude that chromosome pairing plays an important role in trans-suppression and discuss the possibility that terminal deficiency-associated PEV and trans-suppression reflect changes in nuclear positioning of the chromosomes and the gene, and/or the activity and distribution of telomere-binding proteins.

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Erlykin, Anatoly D., et Arnold W. Wolfendale. « DO WE SEE THE ‘IRON PEAK’ ? » Acta Polytechnica 53, A (18 décembre 2013) : 724–27. http://dx.doi.org/10.14311/ap.2013.53.0724.

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Recent measurements of the cosmic ray (CR) energy spectrum in the PeV region and above have confirmed the remarkable sharpness of the knee and revealed another structure at about 70PeV which we call the ‘Iron Peak’. The position and the shape of this structure lead us to associate its likely origin with the same single source responsible for the the knee. We have analysed the shape of the single source spectrum and concluded that its mass composition is rather similar to that for the bulk of CR in the TeV ÷ PeV region. Since it is generally accepted that these CR originate mainly in supernova explosions, this gives an additional argument in favour of our single source being a supernova remnant.

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Kalikulov, O. A., N. O. Saduyev, S. B. Shaulov, V. V. Zhukov, D. Beznosko, Y. S. Mukhamejanov, N. O. Yerezhep et al. « Study of the spatiotemporal structure of extensive air showers at high energies ». Journal of Instrumentation 17, n^o 04 (1 avril 2022) : C04014. http://dx.doi.org/10.1088/1748-0221/17/04/c04014.

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Abstract In a series of works carried out at the Tien-Shan High Altitude Science Station (TSHASS), a penetrating component of extensive air showers (EAS) caused by cosmic rays (CR) with energy of the primary particle above 1 PeV was discovered. The local increase in the energy of secondary hadrons in the EAS cores in the region of the CR spectrum slope change around energy of 3 PeV, the so-called “knee”. The problem of knee formation currently is one of the currently still open mysteries in astrophysics. The studies carried out at the TSHASS show that more information on the knee region can be obtained by studying the characteristics of the EAS cores. At present, a large installation with an area of several hundred square meters is being constructed at the station to study the EAS cores in the “knee” region. The installation is located at an altitude of 3330 meters above sea level near the city of Almaty, Kazakhstan.

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SINEGOVSKY, S. I., A. A. KOCHANOV, T. S. SINEGOVSKAYA, A. MISAKI et N. TAKAHASHI. « ATMOSPHERIC MUON FLUX AT PEV ENERGIES ». International Journal of Modern Physics A 25, n^o 18n19 (30 juillet 2010) : 3733–40. http://dx.doi.org/10.1142/s0217751x10049748.

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In the near future, the energy region above few hundreds of TeV may really be accessible for measurements of the atmospheric muon spectrum with IceCube array. Therefore, one expects that muon flux uncertainties above 50 TeV, related to a poor knowledge of charm production cross-sections and insufficiently examined primary spectra and composition, will be diminished. We give predictions for the very high-energy muon spectrum at sea level, obtained with the three hadronic interaction models, taking into account also the muon contribution due to decays of the charmed hadrons.

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Morcillo, Patrick, et Ross J. MacIntyre. « Genetic and molecular characterization of a variegating hsp70-lacZ fusion gene in the euchromatic 31B region of Drosophila melanogaster ». Genome 44, n^o 4 (1 août 2001) : 698–707. http://dx.doi.org/10.1139/g01-038.

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A hsp70lacZ fusion gene introduced into Drosophila melanogaster at the euchromatic 31B region by P-element transformation displayed a variegated expression with respect to the lacZ fusion protein in the salivary gland cells under heat-shock conditions. The variegation is also reflected by the chromosome puffing pattern. Subsequent transposition of the 31B P element to other euchromatic positions restored wild-type activity, that is, a nonvariegated phenotype. A lower developmental temperature reduced the amount of expression under heat-shock conditions, similar to genes undergoing position-effect variegation (PEV). However, other modifiers of PEV did not affect the expression pattern of the gene. These results show a novel euchromatic tissue-specific variegation that is not associated with classical heterochromatic PEV.Key words: Drosophila, euchromatic position effect, heat shock construct.

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Ismail, A. Haj, et A. AbdelKader. « Optimizing the zenith angle dependence of cosmic ray muons from Charm particles in the knee region : simulation study ». Journal of Physics : Conference Series 2429, n^o 1 (1 février 2023) : 012013. http://dx.doi.org/10.1088/1742-6596/2429/1/012013.

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Abstract The muonic component of air showers is one of the most abundant component of charged particles arriving at the Earth’s surface, and able to penetrate deeply underground, and is very sensitive to the primary mass and energy of the initial cosmic particle. Atmospheric muons are produced in the propagation of different components of extensive air showers. Therefore, variations in the muon ratio, defined as the number of positive over negative charged muons, must be well understood. In this paper, we study the variation of the muon charge ratio of cosmic muons at different zenith angles, and we study the contribution of charm particles in producing atmospheric muons using Monte Carlo showers initiated by two cosmic primaries, proton and iron, with four energies [10 PeV, 100 PeV, 1 EeV, 10 EeV], in the zenith range of [0° to 60°].

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Doherty, Michelle, Daniel Todd, Neil McFerran et Elizabeth M. Hoey. « Sequence analysis of a porcine enterovirus serotype 1 isolate : relationships with other picornaviruses ». Journal of General Virology 80, n^o 8 (1 août 1999) : 1929–41. http://dx.doi.org/10.1099/0022-1317-80-8-1929.

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The majority of the genomic sequence of a porcine enterovirus serotype 1 (PEV-1) isolate was determined. The genome was found to contain a large open reading frame which encoded a leader protein prior to the capsid protein region. This showed no sequence identity to other picornavirus leader regions and the sequence data suggested that it does not possess proteolytic activity. The 2A protease was small and showed considerable sequence identity to the aphthoviruses and to equine rhinovirus serotype 2. The 2A/2B junction possessed the typical cleavage site (NPG/P) exhibited by these viruses. The other proteins shared less than 40% sequence identity with equivalent proteins from other picornavirus genera. Phylogenetic analyses of the P1 and 3D sequences indicated that this virus forms a distinct branch of the family Picornaviridae. On the basis of results presented in this paper PEV-1 has been assigned to a new picornavirus genus. The phylogeny of the virus in relation to other picornaviruses is discussed.

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Westphal, Thomas, et Gunter Reuter. « Recombinogenic Effects of Suppressors of Position-Effect Variegation in Drosophila ». Genetics 160, n^o 2 (1 février 2002) : 609–21. http://dx.doi.org/10.1093/genetics/160.2.609.

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Abstract Compact chromatin structure, induction of gene silencing in position-effect variegation (PEV), and crossing-over suppression are typical features of heterochromatin. To identify genes affecting crossing-over suppression by heterochromatin we tested PEV suppressor mutations for their effects on crossing over in pericentromeric regions of Drosophila autosomes. From the 46 mutations (28 loci) studied, 16 Su(var) mutations of the nine genes Su(var)2-1, Su(var)2-2, Su(var)2-5, Su(var)2-10, Su(var)2-14, Su(var) 2-15, Su(var)3-3, Su(var)3-7, and Su(var)3-9 significantly increase in heterozygotes or by additive effects in double and triple heterozygotes crossing over in the ri-pp region of chromosome 3. Su(var)2-201 and Su(var) 2-1401 display the strongest recombinogenic effects and were also shown to enhance recombination within the light-rolled heterochromatic region of chromosome 2. The dominant recombinogenic effects of Su(var) mutations are most pronounced in proximal euchromatin and are accompanied with significant reduction of meiotic nondisjunction. Our data suggest that crossing-over suppression by heterochromatin is controlled at chromatin structure as well as illustrate the possible effects of heterochromatin on total crossing-over frequencies in the genome.

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Büchner, Kerstin, Peggy Roth, Gunnar Schotta, Veiko Krauss, Harald Saumweber, Gunter Reuter et Rainer Dorn. « Genetic and Molecular Complexity of the Position Effect Variegation Modifier mod(mdg4) in Drosophila ». Genetics 155, n^o 1 (1 mai 2000) : 141–57. http://dx.doi.org/10.1093/genetics/155.1.141.

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Abstract mod(mdg4), also known as E(var)3-93D, is involved in a variety of processes, such as gene silencing in position effect variegation (PEV), the control of gypsy insulator sequences, regulation of homeotic gene expression, and programmed cell death. We have isolated a large number of mod(mdg4) cDNAs, representing 21 different isoforms generated by alternative splicing. The deduced proteins are characterized by a common N terminus of 402 amino acids, including the BTB/POZ-domain. Most of the variable C termini contain a new consensus sequence, including four positioned hydrophobic amino acids and a Cys2His2 motif. Using specific antibodies for two protein isoforms, we demonstrate different distributions of the corresponding proteins on polytene chromosomes. Mutations in the genomic region encoding exons 1–4 show enhancement of PEV and homeotic transformation and affect viability and fertility. Homeotic and PEV phenotypes are enhanced by mutations in other trx-group genes. A transgene containing the common 5′ region of mod(mdg4) that is present in all splice variants known so far partially rescues the recessive lethality of mod(mdg4) mutant alleles. Our data provide evidence that the molecular and genetic complexity of mod(mdg4) is caused by a large set of individual protein isoforms with specific functions in regulating the chromatin structure of different sets of genes throughout development.

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Zell, Roland, Malte Dauber, Andi Krumbholz, Andreas Henke, Eckhard Birch-Hirschfeld, Axel Stelzner, Dieter Prager et Rudiger Wurm. « Porcine Teschoviruses Comprise at Least Eleven Distinct Serotypes : Molecular and Evolutionary Aspects ». Journal of Virology 75, n^o 4 (15 février 2001) : 1620–31. http://dx.doi.org/10.1128/jvi.75.4.1620-1631.2001.

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ABSTRACT Nucleotide sequencing and phylogenetic analysis of 10 recognized prototype strains of the porcine enterovirus (PEV) cytopathic effect (CPE) group I reveals a close relationship of the viral genomes to the previously sequenced strain F65, supporting the concept of a reclassification of this virus group into a new picornavirus genus. Also, nucleotide sequences of the polyprotein-encoding genome region or the P1 region of 28 historic strains and recent field isolates were determined. The data suggest that several closely related but antigenically and molecular distinct serotypes constitute one species within the proposed genus Teschovirus. Based on sequence data and serological data, we propose a new serotype with strain Dresden as prototype. This hitherto unrecognized serotype is closely related to porcine teschovirus 1 (PTV-1, former PEV-1), but induces type-specific neutralizing antibodies. Sequencing of field isolates collected from animals presenting with neurological disorders prove that other serotypes than PTV-1 may also cause polioencephalomyelitis of swine.

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Shaulov, S. B., L. I. Vil’danova, E. A. Kupriyanova, V. A. Ryabov et A. L. Shepetov. « Scaling violation in interaction of cosmic ray hadrons and the nature of the 3 PeV knee in the spectrum of primary cosmic rays ». Journal of Physics G : Nuclear and Particle Physics 48, n^o 12 (29 octobre 2021) : 125202. http://dx.doi.org/10.1088/1361-6471/ac2e58.

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Abstract Energy spectra of the most energetic hadrons in the core region of extensive air showers (EASs) were studied in dependence on the EAS energy E 0 in the hybrid experiment HADRON at the Tien Shan mountain cosmic ray station. For the first time by direct measurement it was found in this experiment that the slope of the power energy spectrum of EAS hadrons diminishes itself locally, and the average hadron energy, correspondingly, increases between the E 0 borders 3 PeV and 20 PeV. Such behavior agrees with threshold appearance in EAS, in the same energy range, of a long-flying penetrative component which was earlier revealed at the Tien Shan station. Now we reconsider this Tien Shan result in comparison with the new data of modern collider experiments. The analysis permits to state unambiguously an astrophysical nature of the penetrative EAS component, and to discuss its probable connection with the origin of the famous knee in the energy spectrum of cosmic rays at E 0 ≃ 3 PeV.

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Khangulyan, Dmitry, Masanori Arakawa et Felix Aharonian. « Detection of ultra-high-energy gamma rays from the Crab Nebula : physical implications ». Monthly Notices of the Royal Astronomical Society 491, n^o 3 (10 décembre 2019) : 3217–24. http://dx.doi.org/10.1093/mnras/stz3261.

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ABSTRACT The Crab Nebula is an extreme particle accelerator that boosts the energy of electrons up to a few PeV ($10^{15} \ \rm eV$), close to the maximum energy allowed theoretically. The physical conditions in the acceleration site and the nature of the acceleration process itself remain highly uncertain. The key information about the highest-energy accelerated particles is contained in the synchrotron and inverse Compton (IC) channels of radiation at energies above 1 MeV and 100 TeV, respectively. A recent report of the detection of an ultra-high-energy gamma-ray signal from the Crab Nebula up to 300 TeV allows us to determine the energy distribution of the highest-energy electrons and to derive the magnetic field strength in the acceleration region, $B\le 120\rm \, \mu G$, in a parameter-free way. This estimate brings new constraints on the properties of non-thermal particle distributions and places important constraints on the magnetohydrodynamic models for the Crab Nebula, in particular on the feasible magnetization and anisotropy of the pulsar wind. The calculations of synchrotron and IC emission show that future observations with instruments that allow detection of the Crab Nebula above 300 TeV and above 1 MeV will clarify the conditions that allow acceleration of electrons beyond PeV energies in the Crab Nebula. In particular, we will be able to verify the hypothetical multicomponent composition of the electron energy distribution, and we will determine the magnetic field strength in the regions responsible for the acceleration of PeV electrons.

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Ulrich, H., R. Glasstetter, T. Antoni, W. D. Apel, F. Badea, K. Bekk, A. Bercuci et al. « Energy spectrum and elemental composition of cosmic rays in the PeV region ». European Physical Journal C 33, S1 (3 février 2004) : s944—s946. http://dx.doi.org/10.1140/epjcd/s2004-03-1632-2.

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Amenomori, M., S. Asano, Y. W. Bao, X. J. Bi, D. Chen, T. L. Chen, W. Y. Chen et al. « Observation of Gamma Rays up to 320 TeV from the Middle-aged TeV Pulsar Wind Nebula HESS J1849−000 ». Astrophysical Journal 954, n^o 2 (1 septembre 2023) : 200. http://dx.doi.org/10.3847/1538-4357/acebce.

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Abstract Gamma rays from HESS J1849−000, a middle-aged TeV pulsar wind nebula (PWN), are observed by the Tibet air shower array and the muon detector array. The detection significance of gamma rays reaches 4.0σ and 4.4σ levels above 25 TeV and 100 TeV, respectively, in units of the Gaussian standard deviation σ. The energy spectrum measured between 40 TeV < E < 320 TeV for the first time is described with a simple power-law function of dN / dE = ( 2.86 ± 1.44 ) × 10 − 16 ( E / 40 TeV ) − 2.24 ± 0.41 TeV − 1 cm − 2 s − 1 . The gamma-ray energy spectrum from the sub-TeV (E < 1 TeV) to sub-PeV (100 TeV < E < 1 PeV) ranges, including the results of previous studies, can be modeled with the leptonic scenario, i.e., inverse Compton scattering by high-energy electrons accelerated by the PWN of PSR J1849−0001. On the other hand, the gamma-ray energy spectrum can also be modeled with the hadronic scenario in which gamma rays are generated from the decay of neutral pions produced by collisions between accelerated cosmic-ray protons and the ambient molecular cloud found in the gamma-ray-emitting region. The cutoff energy of cosmic-ray protons E p,cut is estimated as log 10 ( E p , cut / TeV ) = 3.73 − 0.66 + 2.98 , suggesting that protons are accelerated up to the PeV energy range. Our study thus proposes that HESS J1849−000 should be further investigated as a new candidate as a Galactic PeV cosmic-ray accelerator, or “PeVatron.”

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Martin-Morris, L. E., et S. Henikoff. « Conservation of brown gene trans-inactivation in Drosophila. » Genetics 140, n^o 1 (1 mai 1995) : 193–99. http://dx.doi.org/10.1093/genetics/140.1.193.

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Abstract The mechanism underlying trans-inactivation associated with dominant position effect variegation (PEV) of the Drosophila melanogaster brown gene has been addressed by a comparison with its D. virilis homologue. This comparison revealed: 86% identity between conceptual translation products of the brown gene from these two species, functional homology, as the D. virilis gene rescues a D. melanogaster null brown mutation, and conservation of the sequences required for trans-inactivation, as the D. virilis gene in D. melanogaster is subject to dominant PEV. An extended region of sequence similarity upstream of the open reading frame is observed. As the D. virilis homologue is functionally interchangeable with the D. melanogaster gene, these genes must share regulatory sequences as well as protein coding homology. These results support a model in which trans-inactivation is mediated by a heterochromatin-sensitive transcription factor.

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Cao, Zhen. « LHAASO Status and Physics Results ». EPJ Web of Conferences 280 (2023) : 01003. http://dx.doi.org/10.1051/epjconf/202328001003.

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Status of the LHAASO experiment and its latest results in both γ-ray astronomic observations and charged cosmic ray (CR) measurements are reported in this paper. The discovery of photons around 1 PeV from the Crab, 12 PeVatrons in our galaxy and new sources with emissions above 100 TeV declare the onset of the utral-high-energy γ-ray astronomy. The capability of measurements of spectra of the individual species of CRs, e.g. protons and iron nuclei, starts the new era of the high precision measurement of CRs using the ground based extensive air shower technique. The detection of the highest energy photon at 1.4 PeV from the remote potential source in Cygnus region allows to test of the violation of fundamental physics rules, such as the Lorentz Invariance, and set the highest limits in the tests.

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Iwasaki, Aoi, Keitaro Fujita, Shoichi Ogio, Toshihiro Fujii et Yoshiki Tsunesada. « Performance of the TALE infill experiment as a TA-TALE extension down to the PeV region ». EPJ Web of Conferences 283 (2023) : 06015. http://dx.doi.org/10.1051/epjconf/202328306015.

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The TALE infill experiment is a further extension of TA-TALE detectors to observe low-energy cosmic rays down to the PeV region. TALE infill utilizes the existing TALE-FD detectors, and newly developed "infill" surface detectors with 100 m and 200 m spacing. The new detectors will be deployed at the TALE site in October-November 2022. We present the design and performance of the TALE infill array in the hybrid mode, in terms of the resolutions and biases of arrival direction, energy, and Xmax.

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Vernì, Fiammetta, Renu Gandhi, Michael L. Goldberg et Maurizio Gatti. « Genetic and Molecular Analysis of wings apart-like (wapl), a Gene Controlling Heterochromatin Organization in Drosophila melanogaster ». Genetics 154, n^o 4 (1 avril 2000) : 1693–710. http://dx.doi.org/10.1093/genetics/154.4.1693.

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Abstract Mutations in the X-linked gene wings apart-like (wapl) result in late larval lethality associated with an unusual chromosome morphology. In brain cell metaphases of wapl mutants, sister chromatids of all chromosomes are aligned parallel to each other instead of assuming the typical morphology observed in wild type. This effect is due to a loosening of the adhesion between sister chromatids in the heterochromatic regions of the chromosomes. Despite this aberrant chromosome morphology, mutant brains exhibit normal mitotic parameters, suggesting that heterochromatin cohesion is not essential for proper centromere function. On the basis of these observations, we examined the role of wapl in meiotic chromosome segregation in females. wapl exhibits a clear dominant effect on achiasmate segregation, giving further support to the hypothesis that proximal heterochromatin is involved in chromosome pairing during female meiosis. We also examined whether wapl modulates position-effect variegation (PEV). Our analyses showed that wapl is a dominant suppressor of both white and Stubble variegation, while it is a weak enhancer of brown variegation. wapl maps to region 2D of the X chromosome between Pgd and pn. We identified the wapl gene within a previously conducted chromosomal walk in this region. The wapl transcriptional unit gives rise to two alternatively spliced transcripts 6.5- and 5-kb long. The protein encoded by the larger of these transcripts appears to be conserved among higher eukaryotes and contains a tract of acidic amino acids reminiscent of many chromatin-associated proteins, including two [HP1 and SU(VAR)3-7] encoded by other genes that act as suppressors of PEV.

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Qiao, Bing-Qiang, Yu-Hua Yao, Wei Liu, Qiang Yuan, Xiao-Jun Bi, Hong-Bo Hu et Yi-Qing Guo. « Constraining the Thickness of the Galactic Halo through Cosmic-Ray Anisotropy Using the Spatial-Dependent-Propagation Model ». Universe 9, n^o 8 (4 août 2023) : 363. http://dx.doi.org/10.3390/universe9080363.

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The spatial-dependent-propagation (SDP) model with a nearby source works well to reproduce the coevolving features of both cosmic-ray (CR)-nuclei spectra and anisotropy. However, it is well known that the Sun is actually deviating from the galactic disk. This will lead to a dominating anisotropy in the direction perpendicular to the galactic disk, which is discrepant with current observations. Thus, it is necessary to further investigate the effect of the solar offset on anisotropy. In this work, to the best of our knowledge, this is the first time that the combined studies of the solar offset, nuclei spectra, and anisotropy have been performed based on the SDP model. As a result, to reproduce CR spectra and anisotropy, the thickness of the inner halo (ZIH) needs to increase linearly with the displacement of the Sun. We also know that the PeV anisotropy could be used to estimate the value of the diffusion coefficient, thus breaking the degeneracy between the diffusion coefficient and halo thickness. Therefore, it is a good approach to constrain the halo thickness. Moreover, the anisotropy in the PeV energy region, as a new probe, might also shed new light on constraining the solar offset. It is hoped that the anisotropy of the energies from ∼TeV to PeV can be finely measured with the LHAASO experiment, leading to a better understanding of the thick halo.

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Perrina, Chiara. « The future of the high energy cosmic ray detection : HERD ». EPJ Web of Conferences 209 (2019) : 01040. http://dx.doi.org/10.1051/epjconf/201920901040.

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The High Energy cosmic-Radiation Detection (HERD) facility will be one of the space astronomy payloads on board the future Chinese space station. The ambitious aim of HERD is the direct detection of cosmic rays towards the “knee” region (~ 1 PeV), with a detector able to measure electrons, photons and nuclei with an excellent energy resolution (1% for electrons and photons at 200 GeV and 20% for nuclei at 100 GeV - PeV), an acceptance 10 times the one of present generation missions (~ 1 m2 sr), and long life-time (> 10 years). The primary objectives of HERD are the indirect search for dark matter particles and the precise measurement of energy distribution and composition of cosmic rays from 30 GeV up to a few PeV, determining the origin of the “knee” structure of the spectrum. Furthermore, HERD will monitor the high energy gamma-ray sky from 500 MeV, observing gamma-ray bursts, active galactic nuclei, galactic microquasars, etc. HERD will be composed of a homogeneous calorimeter, surrounded by a particle tracker and a plastic scintillator detector. Two possible trackers are under study: a 5-side tracker made of silicon strip detectors and a 4-side scintillating fiber tracker with a silicon strip top tracker. The total volume of HERD will be (2.3 × 2.3 × 2.6) m3 with a weight of about 4 t. The HERD design, perspectives, expected performances in terms of energy sensitivity and acceptance will be presented in this contribution.

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GOWDA, Jeevan, Anwesha BEHERA, Annam Pavan KUMAR et Ashok JAİSWAR. « First Record of Rhynchorhamphus naga Collette, 1976 (Beloniformes : Hemiramphidae) From Kerala, India, South Eastern Arabian Sea ». Marine Science and Technology Bulletin 11, n^o 4 (31 décembre 2022) : 533–39. http://dx.doi.org/10.33714/masteb.1182270.

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Species, under the genus Rhynchorhamphus (Family: Hemiramphidae), are widely distributed marine groups of fishes. Among four species described from India, only two species, i.e., Rhynchorhamphus georgii and R. maabarica, are reported along the Indian coast. However, during the present study, a specimen collected from the Western Indian Ocean, Chetty harbour, Kerala, the south-west coast of India, has been identified as Rhynchorhamphus naga (Collette, 1976), based on morphology and molecular characters. The species is characterized by D-14; A-14; Pec-9; Pev-6; GR-50 and a prolonged beak (171.82% HL). The species has been reported from Western Central Pacific and several other countries like Brunei Darussalam, Cambodia, Malaysia, Philippines, Singapore, Thailand and Vietnam considered to be endemic to that region. This finding reveals that the species has a wider distribution, as we recorded the species from Kerala, south-west coast of India along the Indian Ocean.

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Roth, M., T. Antoni, W. D. Apela, F. Badea, K. Bekk, A. Bercuci, H. Blümera et al. « Determination of primary energy and mass in the PeV region by Bayesian unfolding techniques ». Nuclear Physics B - Proceedings Supplements 122 (juillet 2003) : 317–20. http://dx.doi.org/10.1016/s0920-5632(03)80408-5.

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Gabici, Stefano, Felix A. Aharonian, Emmanuel Moulin et Aion Viana. « Acceleration of particles up to PeV energies at the galactic centre ». Proceedings of the International Astronomical Union 12, S324 (septembre 2016) : 317–21. http://dx.doi.org/10.1017/s1743921317002332.

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AbstractRecent very high energy observations of the galactic centre region performed by H.E.S.S. revealed the presence of a powerful PeVatron. This is the first of such objects detected, and its most plausible counterpart seems to be associated to Sgr A*, the supermassive black hole in the centre of our galaxy. The implications of this discovery will be discussed, in particular in the context of the problem of the origin of galactic cosmic rays.

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Ner, Sarbjit S., Michael J. Harrington et Thomas A. Grigliatti. « A Role for the Drosophila SU(VAR)3-9 Protein in Chromatin Organization at the Histone Gene Cluster and in Suppression of Position-Effect Variegation ». Genetics 162, n^o 4 (1 décembre 2002) : 1763–74. http://dx.doi.org/10.1093/genetics/162.4.1763.

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Abstract Mutations in the gene for Su(var)3-9 are dominant suppressors of position-effect variegation (PEV). We show that SU(VAR)3-9 is a chromatin-associated protein and identify the large multicopy histone gene cluster (HIS-C) as one of its target loci. The organization of nucleosomes over the entire HIS-C region is altered in Su(var)3-9 mutants and there is a concomitant increase in expression of the histone genes. SU(VAR)3-9 is a histone H3 methyltransferase and, using chromatin immunoprecipitation, we show that SU(VAR)3-9 is present at the HIS-C locus and that the histone H3 at the HIS-C locus is methylated. We propose that SU(VAR)3-9 is involved in packaging HIS-C into a distinct chromatin domain that has some of the characteristics of β-heterochromatin. We suggest that methylation of histone H3 is important for the chromatin structure at HIS-C. The chromosomal deficiency for the HIS-C is also a suppressor of PEV. In contrast to what might be expected, we show that hemizygosity for the HIS-C locus leads to a substantial increase in the histone transcripts.

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Leal, Élcio, Adriana Luchs, Flávio Augusto de Pádua Milagres, Shirley Vasconcelos Komninakis, Danielle Elise Gill, Márcia Cristina Alves Brito Sayão Lobato, Rafael Brustulin et al. « Recombinant Strains of Human Parechovirus in Rural Areas in the North of Brazil ». Viruses 11, n^o 6 (29 mai 2019) : 488. http://dx.doi.org/10.3390/v11060488.

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We characterized the 24 nearly full-length genomes of human parechoviruses (PeV) from children in the north of Brazil. The initial phylogenetic analysis indicated that 17 strains belonged to genotype 1, 5 to genotype 4, and 1 to genotype 17. A more detailed analysis revealed a high frequency of recombinant strains (58%): A total of 14 of our PeV-As were chimeric, with four distinct recombination patterns identified. Five strains were composed of genotypes 1 and 5 (Rec1/5); five strains shared a complex mosaic pattern formed by genotypes 4, 5, and 17 (Rec4/17/5); two strains were composed of genotypes 1 and 17 (Rec1/17); and two strains were composed of genotype 1 and an undetermined strain (Rec1/und). Coalescent analysis based on the Vp1 gene, which is free of recombination, indicated that the recombinant strains most likely arose in this region approximately 30 years ago. They are present in high frequencies and are circulating in different small and isolated cities in the state of Tocantins. Further studies will be needed to establish whether the detected recombinant strains have been replacing parental strains or if they are co-circulating in distinct frequencies in Tocantins.

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Peretti, Enrico, Pasquale Blasi, Felix Aharonian, Giovanni Morlino et Pierre Cristofari. « Contribution of starburst nuclei to the diffuse gamma-ray and neutrino flux ». Monthly Notices of the Royal Astronomical Society 493, n^o 4 (13 mars 2020) : 5880–91. http://dx.doi.org/10.1093/mnras/staa698.

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ABSTRACT In nuclei of starburst galaxies (SBGs), the combination of an enhanced rate of supernova explosions and a high gas density suggests that cosmic rays (CRs) can be efficiently produced, and that most of them lose their energy before escaping these regions, resulting in a large flux of secondary products, including neutrinos. Although the flux inferred from an individual starburst region is expected to be well below the sensitivity of current neutrino telescopes, such sources may provide a substantial contribution to the diffuse neutrino flux measured by IceCube. Here, we compute the gamma-ray and neutrino flux due to SBGs based on a physical model of CR transport in a starburst nucleus, and accounting for the redshift evolution of the number density of starburst sources as inferred from recent measurements of the star formation rate. The model accounts for gamma-ray absorption both inside the sources and in the intergalactic medium. The latter process is responsible for electromagnetic cascades, which also contribute to the diffuse gamma-ray background at lower energies. The conditions for acceleration of CR protons up to energies exceeding $\sim 10 \, \rm PeV$ in starburst regions, necessary for the production of PeV neutrinos, are investigated in a critical way. We show that starburst nuclei can account for the diffuse neutrino flux above $\sim 200 \, \rm TeV$, thereby producing $\lesssim 40 {\rm { per\, cent}}$ of the extragalactic diffuse gamma-ray background. Below $\sim 200 \, \rm TeV$, the flux from starburst appears to be somewhat lower than the observed one, where both the Galactic contribution and the flux of atmospheric neutrinos may account for the difference.

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Ayoub, Nabieh, Idit Goldshmidt et Amikam Cohen. « Position Effect Variegation at the Mating-Type Locus of Fission Yeast : A cis-Acting Element Inhibits Covariegated Expression of Genes in the Silent and Expressed Domains ». Genetics 152, n^o 2 (1 juin 1999) : 495–508. http://dx.doi.org/10.1093/genetics/152.2.495.

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Abstract Schizosaccharomyces pombe switches its mating type by transposing a copy of unexpressed genes from the respective mat2 or mat3 cassettes to mat1. The donor cassettes are located in a silent domain that is separated from the expressed mat1 cassette by the L region. We monitored the expression of ade6 from sites in the L region and examined the relationship between the expression state at these sites and at sites within the silent domain. Results indicate that: (1) the silent domain extends into the L region, but repression is gradually alleviated with increasing distance from mat2, and overexpression of swi6 enhances PEV in the L region; (2) a transcriptionally active chromatin state, associated with reporter gene expression in the L region, spreads toward the silent domain; (3) a cis-acting element, located at the junction between the L region and mat2-P, ensures repression in the silent domain, regardless of the expression state in the L region; and (4) repression in mat1-P cells is less stringently controlled than in mat1-M cells. We discuss the functional organization of the mat region and genetic elements that ensure separation between repressed and derepressed domains.

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Morlino, G., P. Blasi, E. Peretti et P. Cristofari. « Particle acceleration in winds of star clusters ». Monthly Notices of the Royal Astronomical Society 504, n^o 4 (15 mars 2021) : 6096–105. http://dx.doi.org/10.1093/mnras/stab690.

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ABSTRACT The origin of cosmic rays in our Galaxy remains a subject of active debate. While supernova remnant (SNR) shocks are often invoked as the sites of acceleration, it is now widely accepted that the difficulties of such sources in reaching PeV energies are daunting and it seems likely that only a subclass of rare remnants can satisfy the necessary conditions. Moreover, the spectra of cosmic rays escaping the remnants have a complex shape that is not obviously the same as the spectra observed at the Earth. Here, we investigate the process of particle acceleration at the termination shock that develops in the bubble excavated by star clusters’ winds in the interstellar medium. While the main limitation to the maximum energy in SNRs comes from the need for effective wave excitation upstream so as to confine particles in the near-shock region and speed up the acceleration process, at the termination shock of star clusters the confinement of particles upstream is guaranteed by the geometry of the problem. We develop a theory of diffusive shock acceleration at such shock and we find that the maximum energy may reach the PeV region for powerful clusters in the high end of the luminosity tail for these sources. A crucial role in this problem is played by the dissipation of energy in the wind to magnetic perturbations. Under reasonable conditions, the spectrum of the accelerated particles has a power-law shape with a slope 4/4.3, in agreement with what is required based upon standard models of cosmic ray transport in the Galaxy.

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Abdulsttar, Marwah M., A. A. Al-Rubaiee et Abdul Halim K. Ali. « Demonstrating of Cosmic Ray Characteristics by Estimating the Cherenkov Light Lateral Distribution Function for Yakutsk Array as a Function of the Zenith Angle ». International Letters of Chemistry, Physics and Astronomy 67 (juin 2016) : 21–30. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.67.21.

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Cherenkov light lateral distribution function (CLLDF) in Extensive Air Showers (EAS) for different primary particles (e-, n , p, F, K and Fe) was simulated using CORSIKA code for conditions and configurations of Yakutsk EAS array with the fixed primary energy 3 PeV around the knee region at different zenith angles. Basing on the results of CLLDF numerical simulation, sets of approximated functions are reconstructed for different primary particles as a function of the zenith angle. A comparison of the parametrized CLLDF with that simulated with Yakutsk EAS array is verified.The parameterized CLLDF also is compared with that measured on the Yakutsk EAS array.

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Abdulsttar, Marwah M., A. A. Al-Rubaiee et Abdul Halim K. Ali. « Demonstrating of Cosmic Ray Characteristics by Estimating the Cherenkov Light Lateral Distribution Function for Yakutsk Array as a Function of the Zenith Angle ». International Letters of Chemistry, Physics and Astronomy 67 (30 juin 2016) : 21–30. http://dx.doi.org/10.56431/p-p51584.

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Cherenkov light lateral distribution function (CLLDF) in Extensive Air Showers (EAS) for different primary particles (e-, n , p, F, K and Fe) was simulated using CORSIKA code for conditions and configurations of Yakutsk EAS array with the fixed primary energy 3 PeV around the knee region at different zenith angles. Basing on the results of CLLDF numerical simulation, sets of approximated functions are reconstructed for different primary particles as a function of the zenith angle. A comparison of the parametrized CLLDF with that simulated with Yakutsk EAS array is verified.The parameterized CLLDF also is compared with that measured on the Yakutsk EAS array.

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Zhang, Yanchao, Jinfu Du, Jin Mao et Min Xu. « Dynamic Analysis of High-Speed Helical Gear Transmission in Pure Electric Vehicle Gearbox ». Shock and Vibration 2020 (5 décembre 2020) : 1–19. http://dx.doi.org/10.1155/2020/6639372.

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This study is to systematically analyze the influences of time-varying meshing stiffness (TVMS) and meshing impact on the dynamic characteristics of high-speed gear transmission in the two-stage pure electric vehicle (PEV) gearbox, as well as the effect of tooth surface modification on the vibration control. First, the dynamic model was established, and the TVMS and meshing impact were calculated. Then, the vibration characteristics of single-stage and two-stage helical gear transmission were analyzed under three different excitation conditions, excitation of TVMS, excitation of meshing impact, and excitation of both. The results show that the effect of rotating speed on the system vibration is not significant outside the resonant region under the excitation of TVMS, while the effect of meshing impact becomes the main exciting component with the increasing rotating speed. The vibrations of the two gear pairs interact with each other; the vibration frequency of one gear pair contains both its meshing frequency and the coupling frequency of the other gear pair. Tooth surface modification in the input-stage gear pair can reduce the vibration of both the input- and the output-stage obviously; that is, more attention should be paid to the input-stage gear pair in the modification design of PEV gearbox.

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Hanif, Fatima, et Ahsan Ali. « Direct runoff hydrograph model’s collation for a Pakistan’s region ». Mehran University Research Journal of Engineering and Technology 41, n^o 4 (14 février 2023) : 198. http://dx.doi.org/10.22581/muet1982.2204.20.

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Rainfall-Runoff modeling is among the classical applications of hydrology. This paper examines the results of 3 hydrologic approaches, particularly Clark Model, Nash Model, and Geomorphic Instantaneous Unit Hydrograph Model. Assumptions are forwarded for the long run use of the Rawalpindi Division, Pakistan’s Small Dam Organization. The catchment of Shahpur Dam was an area under consideration for the study. The Digital elevation model (DEM) was implicated to measure the Nash and Clark model’s geomorphic parameters. Using ArcGIS, catchment satellite imagery was processed to estimate geomorphological parameters. The models have been applied to multiple storm cases. Geographic Instantaneous Unit Hydrograph (GIUH) model gave direct surface runoff hydrograph, whereas, on measured precipitation excess rainfall hyetograph was obtained. Four types of statistical parameters, namely efficiency of the model (EFF), percentage defect in time to attain peak (PETP), percent defect in attained peak Q (PEP), percentage defect in runoff rate (PEV) are used to check model’s efficiency. The comparison is done between the findings of Clark and Nash GIUH models and the original Clark and Nash models. It was observed that GIUH models are equally good even when optimization is done for Clark and Nash model’s parameters. Since the results obtained from these models are more credible, so, these models can be used in ungauged catchments to estimate the hydrographs.

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Marinelli, A., A. Ambrosone, W. I. Ibnsalih, G. Miele, P. Migliozzi, O. Pisanti, A. Sharma et al. « KM3NeT/ARCA expectations in view of a novel multimessenger study of starburst galaxies ». Journal of Instrumentation 16, n^o 12 (1 décembre 2021) : C12016. http://dx.doi.org/10.1088/1748-0221/16/12/c12016.

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Abstract Starburst galaxies (SBGs) and more in general star-forming galaxies represent a class of galaxies with a high star formation rate (up to 100M ⊙/year). Despite their low luminosity, they can be considered as guaranteed “factories” of high energy neutrinos, being “reservoirs” of accelerated cosmic rays and hosting a high density target gas in the central region. In this contribution we present a novel multimessenger study of these sources and the possibility of observing their neutrino signals with the KM3NeT/ARCA telescope. The differential sensitivity for different SBG scenarios is reported considering track-like neutrino events in the 100 GeV–100 PeV energy range.

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Pallis, Constantinos. « PeV-Scale SUSY and Cosmic Strings from F-Term Hybrid Inflation ». Universe 10, n^o 5 (8 mai 2024) : 211. http://dx.doi.org/10.3390/universe10050211.

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We consider F-term hybrid inflation (FHI) and SUSY breaking in the context of a B−L extension of the MSSM that largely respects a global U(1)R symmetry. The hidden sector Kaehler manifold enjoys an enhanced SU(1,1)/U(1) symmetry, with the scalar curvature determined by the achievement of a SUSY-breaking de Sitter vacuum without undesirable tuning. FHI turns out to be consistent with the data, provided that the magnitude of the emergent soft tadpole term is confined to the range (1.2–100) TeV, and it is accompanied by the production of B−L cosmic strings. If these are metastable, they are consistent with the present observations from PTA experiments on the stochastic background of gravitational waves with dimensionless tension Gμcs≃(1−9.2)·10−8. The μ parameter of the MSSM arises by appropriately adapting the Giudice–Masiero mechanism and facilitates the out-of-equilibrium decay of the R saxion at a reheat temperature lower than about 71 GeV. Due to the prolonged matter-dominated era, the gravitational wave signal is suppressed at high frequencies. The SUSY mass scale turns out to lie in the PeV region.

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Boros, Ákos, Péter Pankovics, Nick J. Knowles et Gábor Reuter. « Natural interspecies recombinant bovine/porcine enterovirus in sheep ». Journal of General Virology 93, n^o 9 (1 septembre 2012) : 1941–51. http://dx.doi.org/10.1099/vir.0.041335-0.

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Members of the genus Enterovirus (family Picornaviridae) are believed to be common and widespread among humans and different animal species, although only a few enteroviruses have been identified from animal sources. Intraspecies recombination among human enteroviruses is a well-known phenomenon, but only a few interspecies examples have been reported and, to our current knowledge, none of these have involved non-primate enteroviruses. In this study, we report the detection and complete genome characterization (using RT-PCR and long-range PCR) of a natural interspecies recombinant bovine/porcine enterovirus (ovine enterovirus type 1; OEV-1) in seven (44 %) of 16 faecal samples from 3-week-old domestic sheep (Ovis aries) collected in two consecutive years. Phylogenetic analysis of the complete coding region revealed that OEV-1 (ovine/TB4-OEV/2009/HUN; GenBank accession no. JQ277724) was a novel member of the species Porcine enterovirus B (PEV-B), implying the endemic presence of PEV-B viruses among sheep. However, the 5′ UTR of OEV-1 showed a high degree of sequence and structural identity to bovine enteroviruses. The presumed recombination breakpoint was mapped to the end of the 5′ UTR at nucleotide position 814 using sequence and SimPlot analyses. The interspecies-recombinant nature of OEV-1 suggests a closer relationship among bovine and porcine enteroviruses, enabling the exchange of at least some modular genetic elements that may evolve independently.

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Bertaina, M., G. Battistoni, S. Muraro, G. Navarra et A. Stamerra. « The cosmic ray primary spectrum in the transition region between direct and indirect measurements (10 TeV - 10 PeV) ». Journal of Physics : Conference Series 120, n^o 6 (1 juillet 2008) : 062023. http://dx.doi.org/10.1088/1742-6596/120/6/062023.

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E. Bertaina, M., G. Battistoni, S. Muraro, G. Navarra et A. Stamerra. « The Cosmic Ray Primary Spectrum in the Transition Region between Direct and Indirect Measurements (10 TeV–10 PeV) ». Journal of the Physical Society of Japan 78, Suppl.A (janvier 2009) : 210–13. http://dx.doi.org/10.1143/jpsjs.78sa.210.

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Velpuri, Naga Manohar, Gabriel B. Senay, Jessica M. Driscoll, Samuel Saxe, Lauren Hay, William Farmer et Julie Kiang. « Gravity Recovery and Climate Experiment (GRACE) Storage Change Characteristics (2003–2016) over Major Surface Basins and Principal Aquifers in the Conterminous United States ». Remote Sensing 11, n^o 8 (18 avril 2019) : 936. http://dx.doi.org/10.3390/rs11080936.

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In this research, we characterized the changes in the Gravity Recovery and Climate Experiment (GRACE) monthly total water storage anomaly (TWSA) in 18 surface basins and 12 principal aquifers in the conterminous United States during 2003–2016. Regions with high variability in storage were identified. Ten basins and four aquifers showed significant changes in storage. Eight surface basins and eight aquifers were found to show decadal stability in storage. A pixel-based analysis of storage showed that the New England basin and North Atlantic Coastal Plain aquifer showed the largest area under positive storage change. By contrast, the Lower Colorado and California basins showed the largest area under negative change. This study found that historically wetter regions (with more storage) are becoming wetter, and drier regions (with less storage) are becoming drier. Fourier analysis of the GRACE data showed that while all basins exhibited prominent annual periodicities, significant sub-annual and multi-annual cycles also exist in some basins. The storage turnover period was estimated to range between 6 and 12 months. The primary explanatory variable (PEV) of TWSA was identified for each region. This study provides new insights on several aspects of basin or aquifer storage that are important for understanding basin and aquifer hydrology.

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