100 research outputs found
Stem cell factor receptor (c-KIT) codon 816 mutations predict development of bilateral testicular germ-cell tumors
Testicular germ-cell tumors (TGCTs) of adolescents and adults originate
from intratubular germ cell neoplasia (ITGCN), which is composed of the
malignant counterparts of embryonal germ cells. ITGCN cells are
characterized, among others, by the presence of stem cell factor receptor
c-KIT. Once established, ITGCN will always progress to invasiveness.
Approximately 2.5-5% of patients with a TGCT will develop bilateral
disease and require complete castration, resulting in infertility, a need
for lifelong androgen replacement, and psychological stress. To date, the
only way to predict a contralateral tumor is surgical biopsy of the
contralateral testis to demonstrate ITGCN. We did a retrospective study of
224 unilateral and 61 proven bilateral TGCTs (from 46 patients, in three
independently collected series in Europe) for the presence of activating
c-KIT codon 816 mutations. A c-KIT codon 816 mutation was found in three
unilateral TGCT (1.3%), and in 57 bilateral TGCTs (93%; P < 0.0001). In
the two wild-type bilateral tumors for which ITGCN was available, the
preinvasive cells contained the mutation. The mutations were somatic in
origin and identical in both tumors. We conclude that somatic activating
codon 816 c-KIT mutations are associated with development of bilateral
TGCT. Detection of c-KIT codon 816 mutations in unilateral TGCT identifies
patients at risk for bilateral disease. These patients may undergo
tailored treatment to prevent the development of bilateral disease, with
retention of testicular hormonal function
Identification of independent association signals and putative functional variants for breast cancer risk through fine-scale mapping of the 12p11 locus.
BACKGROUND: Multiple recent genome-wide association studies (GWAS) have identified a single nucleotide polymorphism (SNP), rs10771399, at 12p11 that is associated with breast cancer risk. METHOD: We performed a fine-scale mapping study of a 700 kb region including 441 genotyped and more than 1300 imputed genetic variants in 48,155 cases and 43,612 controls of European descent, 6269 cases and 6624 controls of East Asian descent and 1116 cases and 932 controls of African descent in the Breast Cancer Association Consortium (BCAC; http://bcac.ccge.medschl.cam.ac.uk/ ), and in 15,252 BRCA1 mutation carriers in the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). Stepwise regression analyses were performed to identify independent association signals. Data from the Encyclopedia of DNA Elements project (ENCODE) and the Cancer Genome Atlas (TCGA) were used for functional annotation. RESULTS: Analysis of data from European descendants found evidence for four independent association signals at 12p11, represented by rs7297051 (odds ratio (OR) = 1.09, 95 % confidence interval (CI) = 1.06-1.12; P = 3 × 10(-9)), rs805510 (OR = 1.08, 95 % CI = 1.04-1.12, P = 2 × 10(-5)), and rs1871152 (OR = 1.04, 95 % CI = 1.02-1.06; P = 2 × 10(-4)) identified in the general populations, and rs113824616 (P = 7 × 10(-5)) identified in the meta-analysis of BCAC ER-negative cases and BRCA1 mutation carriers. SNPs rs7297051, rs805510 and rs113824616 were also associated with breast cancer risk at P < 0.05 in East Asians, but none of the associations were statistically significant in African descendants. Multiple candidate functional variants are located in putative enhancer sequences. Chromatin interaction data suggested that PTHLH was the likely target gene of these enhancers. Of the six variants with the strongest evidence of potential functionality, rs11049453 was statistically significantly associated with the expression of PTHLH and its nearby gene CCDC91 at P < 0.05. CONCLUSION: This study identified four independent association signals at 12p11 and revealed potentially functional variants, providing additional insights into the underlying biological mechanism(s) for the association observed between variants at 12p11 and breast cancer risk.UK funding includes Cancer Research UK and NIH.This is the final version of the article. It first appeared from BioMed Central via http://dx.doi.org/10.1186/s13058-016-0718-
Measurement of jet suppression in central Pb-Pb collisions at root s(NN)=2.76 TeV
The transverse momentum(p(T)) spectrum and nuclear modification factor (R-AA) of reconstructed jets in 0-10% and 10-30% central Pb-Pb collisions at root s(NN) = 2.76 TeV were measured. Jets were reconstructed using the anti-k(T) jet algorithm with a resolution parameter of R = 0.2 from charged and neutral particles, utilizing the ALICE tracking detectors and Electromagnetic Calorimeter (EMCal). The jet p(T) spectra are reported in the pseudorapidity interval of \eta(jet)\ 5 GeV/c to suppress jets constructed from the combinatorial background in Pb-Pb collisions. The leading charged particle requirement applied to jet spectra both in pp and Pb-Pb collisions had a negligible effect on the R-AA. The nuclear modification factor R-AA was found to be 0.28 +/- 0.04 in 0-10% and 0.35 +/- 0.04 in 10-30% collisions, independent of p(T), jet within the uncertainties of the measurement. The observed suppression is in fair agreement with expectations from two model calculations with different approaches to jet quenching. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V.Peer reviewe
Genome-Wide Association Study in BRCA1 Mutation Carriers Identifies Novel Loci Associated with Breast and Ovarian Cancer Risk
BRCA1-associated breast and ovarian cancer risks can be modified by common genetic variants. To identify further cancer risk-modifying loci, we performed a multi-stage GWAS of 11,705 BRCA1 carriers (of whom 5,920 were diagnosed with breast and 1,839 were diagnosed with ovarian cancer), with a further replication in an additional sample of 2,646 BRCA1 carriers. We identified a novel breast cancer risk modifier locus at 1q32 for BRCA1 carriers (rs2290854, P = 2.7×10-8, HR = 1.14, 95% CI: 1.09-1.20). In addition, we identified two novel ovarian cancer risk modifier loci: 17q21.31 (rs17631303, P = 1.4×10-8, HR = 1.27, 95% CI: 1.17-1.38) and 4q32.3 (rs4691139, P = 3.4×10-8, HR = 1.20, 95% CI: 1.17-1.38). The 4q32.3 locus was not associated with ovarian cancer risk in the general population or BRCA2 carriers, suggesting a BRCA1-specific associat
The predictive ability of the 313 variant–based polygenic risk score for contralateral breast cancer risk prediction in women of European ancestry with a heterozygous BRCA1 or BRCA2 pathogenic variant
PURPOSE : To evaluate the association between a previously published 313 variant–based breast cancer (BC) polygenic risk score
(PRS313) and contralateral breast cancer (CBC) risk, in BRCA1 and BRCA2 pathogenic variant heterozygotes.
METHODS : We included women of European ancestry with a prevalent first primary invasive BC (BRCA1 = 6,591 with 1,402
prevalent CBC cases; BRCA2 = 4,208 with 647 prevalent CBC cases) from the Consortium of Investigators of Modifiers of BRCA1/2
(CIMBA), a large international retrospective series. Cox regression analysis was performed to assess the association between overall
and ER-specific PRS313 and CBC risk.
RESULTS : For BRCA1 heterozygotes the estrogen receptor (ER)-negative PRS313 showed the largest association with CBC risk, hazard
ratio (HR) per SD = 1.12, 95% confidence interval (CI) (1.06–1.18), C-index = 0.53; for BRCA2 heterozygotes, this was the ER-positive
PRS313, HR= 1.15, 95% CI (1.07–1.25), C-index = 0.57. Adjusting for family history, age at diagnosis, treatment, or pathological
characteristics for the first BC did not change association effect sizes. For women developing first BC < age 40 years, the cumulative
PRS313 5th and 95th percentile 10-year CBC risks were 22% and 32% for BRCA1 and 13% and 23% for BRCA2 heterozygotes,
respectively.
CONCLUSION : The PRS313 can be used to refine individual CBC risks for BRCA1/2 heterozygotes of European ancestry, however the
PRS313 needs to be considered in the context of a multifactorial risk model to evaluate whether it might influence clinical decisionmaking.This work was supported by the Alpe d’HuZes/Dutch Cancer Society (KWF
Kankerbestrijding) project 6253 and Dutch Cancer Society (KWF Kankerbestrijding)
project UL2014-7473. CIMBA: The CIMBA data management and data analysis were
supported by Cancer Research–UK grants C12292/A20861, C12292/A11174. G.C.T.
and A.B.S. are NHMRC Research Fellows. iCOGS: the European Community’s Seventh
Framework Programme under grant agreement number 223175 (HEALTH-F2-2009-
223175) (COGS), Cancer Research UK (C1287/A10118, C1287/A 10710, C12292/
A11174, C1281/A12014, C5047/A8384, C5047/A15007, C5047/A10692, C8197/
A16565), the National Institutes of Health (CA128978) and Post-Cancer GWAS
initiative (1U19 CA148537, 1U19 CA148065 and 1U19 CA148112–the GAME-ON
initiative), the Department of Defence (W81XWH-10-1-0341), the Canadian Institutes
of Health Research (CIHR) for the CIHR Team in Familial Risks of Breast Cancer (CRN-
87521), and the Ministry of Economic Development, Innovation and Export Trade
(PSR-SIIRI-701), Komen Foundation for the Cure, the Breast Cancer Research
Foundation, and the Ovarian Cancer Research Fund. OncoArray: the PERSPECTIVE
and PERSPECTIVE I&I projects funded by the Government of Canada through
Genome Canada and the Canadian Institutes of Health Research, the Ministère de
l’Économie, de la Science et de l’Innovation du Québec through Genome Québec,
and the Quebec Breast Cancer Foundation; the NCI Genetic Associations and
Mechanisms in Oncology (GAME-ON) initiative and Discovery, Biology and Risk of
Inherited Variants in Breast Cancer (DRIVE) project (NIH grants U19 CA148065 and
X01HG007492); and Cancer Research UK (C1287/A10118 and C1287/A16563). BCFR:
UM1 CA164920 from the National Cancer Institute. The content of this paper does
not necessarily reflect the views or policies of the National Cancer Institute or any of
the collaborating centers in the Breast Cancer Family Registry (BCFR), nor does
mention of trade names, commercial products, or organizations imply endorsement
by the US Government or the BCFR. BFBOCC: Lithuania (BFBOCC-LT): Research
Council of Lithuania grant SEN-18/2015. BIDMC: Breast Cancer Research Foundation.
BMBSA: Cancer Association of South Africa (PI Elizabeth J. van Rensburg). BRI-COH: S.
L.N. is partially supported by the Morris and Horowitz Families Professorship. CNIO:
Spanish Ministry of Health PI16/00440 supported by FEDER funds, the Spanish
Ministry of Economy and Competitiveness (MINECO) SAF2014-57680-R and the Spanish Research Network on Rare diseases (CIBERER). COH-CCGCRN: Research
reported in this publication was supported by the National Cancer Institute of the
National Institutes of Health under grant number R25CA112486, and RC4CA153828
(PI: J. Weitzel) from the National Cancer Institute and the Office of the Director,
National Institutes of Health. The content is solely the responsibility of the authors
and does not necessarily represent the official views of the National Institutes of
Health. CONSIT TEAM: Associazione Italiana Ricerca sul Cancro (AIRC; IG2015 number
16732) to P. Peterlongo. DEMOKRITOS: European Union (European Social Fund–ESF)
and Greek national funds through the Operational Program “Education and Lifelong
Learning” of the National Strategic Reference Framework (NSRF)–Research Funding
Program of the General Secretariat for Research & Technology: SYN11_10_19 NBCA.
Investing in knowledge society through the European Social Fund. DFKZ: German
Cancer Research Center. EMBRACE: Cancer Research UK Grants C1287/A10118 and
C1287/A11990. D.G.E. and F.L. are supported by an NIHR grant to the Biomedical
Research Centre, Manchester. The Investigators at The Institute of Cancer Research
and The Royal Marsden NHS Foundation Trust are supported by an NIHR grant to the
Biomedical Research Centre at The Institute of Cancer Research and The Royal
Marsden NHS Foundation Trust. R.E. and E.B. are supported by Cancer Research UK
Grant C5047/A8385. R.E. is also supported by NIHR support to the Biomedical
Research Centre at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust. FCCC: A.K.G. was in part funded by the NCI (R01 CA214545), The
University of Kansas Cancer Center Support Grant (P30 CA168524), The Kansas
Institute for Precision Medicine (P20 GM130423), and the Kansas Bioscience Authority
Eminent Scholar Program. A.K.G. is the Chancellors Distinguished Chair in Biomedical
Sciences Professorship. FPGMX: A. Vega is supported by the Spanish Health Research
Foundation, Instituto de Salud Carlos III (ISCIII), partially supported by FEDER funds
through Research Activity Intensification Program (contract grant numbers: INT15/
00070, INT16/00154, INT17/00133), and through Centro de Investigación Biomédica
en Red de Enferemdades Raras CIBERER (ACCI 2016: ER17P1AC7112/2018);
Autonomous Government of Galicia (Consolidation and structuring program:
IN607B), and by the Fundación Mutua Madrileña. The German Consortium for
Hereditary Breast and Ovarian Cancer (GC-HBOC) is funded by the German Cancer
Aid (110837, 70111850, coordinator: Rita K. Schmutzler, Cologne) and the Ministry for
Innovation, Science and Research of the State of North Rhine-Westphalia (#323-
8.0302.16.02-132142). GEMO: initially funded by the French National Institute of
Cancer (INCa, PHRC Ile de France, grant AOR 01 082, 2001-2003, grant 2013-1-BCB-01-
ICH-1), the Association “Le cancer du sein, parlons-en!” Award (2004), the Association
for International Cancer Research (2008-2010), and the Foundation ARC pour la
recherche sur le cancer (grant PJA 20151203365). It also received support from the
Canadian Institute of Health Research for the “CIHR Team in Familial Risks of Breast
Cancer” program (2008–2013), and the European commission FP7, Project
«Collaborative Ovarian, breast and prostate Gene-environment Study (COGS),
Large-scale integrating project» (2009–2013). GEMO is currently supported by the
INCa grant SHS-E-SP 18-015. GEORGETOWN: The Survey, Recruitment, and Biospecimen
Collection Shared Resource at Georgetown University (NIH/NCI grant P30-
CA051008), the Fisher Center for Hereditary Cancer and Clinical Genomics Research,
and the Nina Hyde Center for Breast Cancer Research. G-FAST: Bruce Poppe is a
senior clinical investigator of FWO. Mattias Van Heetvelde obtained funding from
IWT. HCSC: Spanish Ministry of Health PI15/00059, PI16/01292, and CB-161200301
CIBERONC from ISCIII (Spain), partially supported by European Regional Development
FEDER funds. HEBCS: Helsinki University Hospital Research Fund, the Finnish Cancer
Society and the Sigrid Juselius Foundation. The HEBON study is supported by the
Dutch Cancer Society grants NKI1998-1854, NKI2004-3088, NKI2007-3756, the Netherlands Organisation of Scientific Research grant NWO 91109024, the Pink
Ribbon grants 110005 and 2014-187.WO76, the BBMRI grant NWO 184.021.007/CP46
and the Transcan grant JTC 2012 Cancer 12-054. HRBCP: Hong Kong Sanatorium and
Hospital, Dr Ellen Li Charitable Foundation, The Kerry Group Kuok Foundation,
National Institute of Health1R 03CA130065, and North California Cancer Center.
HUNBOCS: Hungarian Research Grants KTIA-OTKA CK-80745, NKFI_OTKA K-112228
and TUDFO/51757/2019-ITM. ICO: Contract grant sponsor: Supported by the Carlos III
National Health Institute funded by FEDER funds–a way to build Europe–(PI16/00563,
PI19/00553 and CIBERONC); the Government of Catalonia (Pla estratègic de recerca i
innovació en salut (PERIS) Project MedPerCan, 2017SGR1282 and 2017SGR496); and
CERCA program.IHCC: supported by grant PBZ_KBN_122/P05/2004 and the program
of the Minister of Science and Higher Education under the name “Regional Initiative
of Excellence” in 2019–2022 project number 002/RID/2018/19 amount of financing 12
000 000 PLN. ILUH: Icelandic Association “Walking for Breast Cancer Research” and by
the Landspitali University Hospital Research Fund. INHERIT: Canadian Institutes of
Health Research for the “CIHR Team in Familial Risks of Breast Cancer” program–grant
CRN-87521 and the Ministry of Economic Development, Innovation and Export
Trade–grant # PSR-SIIRI-701. IOVHBOCS: Ministero della Salute and “5×1000” Istituto
Oncologico Veneto grant. IPOBCS: Liga Portuguesa Contra o Cancro. kConFab: The
National Breast Cancer Foundation, and previously by the National Health and
Medical Research Council (NHMRC), the Queensland Cancer Fund, the Cancer
Councils of New South Wales, Victoria, Tasmania and South Australia, and the Cancer
Foundation of Western Australia. KOHBRA: the Korea Health Technology R&D Project
through the Korea Health Industry Development Institute (KHIDI), and the National
R&D Program for Cancer Control, Ministry of Health & Welfare, Republic of Korea
(HI16C1127; 1020350; 1420190). KUMC: NIGMS P20 GM130423 (to A.K.G.). MAYO: NIH
grants CA116167, CA192393 and CA176785, an NCI Specialized Program of Research
Excellence (SPORE) in Breast Cancer (CA116201), and a grant from the Breast Cancer
Research Foundation. MCGILL: Jewish General Hospital Weekend to End Breast
Cancer, Quebec Ministry of Economic Development, Innovation and Export Trade.
Marc Tischkowitz is supported by the funded by the European Union Seventh
Framework Program (2007Y2013)/European Research Council (Grant No. 310018).
MODSQUAD: MH CZ–DRO (MMCI, 00209805) and LM2018125, MEYS–NPS I–LO1413 to LF, and by Charles University in Prague project UNCE204024 (MZ). MSKCC: the
Breast Cancer Research Foundation, the Robert and Kate Niehaus Clinical Cancer
Genetics Initiative, the Andrew Sabin Research Fund and a Cancer Center Support
Grant/Core Grant (P30 CA008748). NAROD: 1R01 CA149429-01. NCI: the Intramural
Research Program of the US National Cancer Institute, NIH, and by support services
contracts NO2-CP-11019-50, N02-CP-21013-63 and N02-CP-65504 with Westat, Inc,
Rockville, MD. NICCC: Clalit Health Services in Israel, the Israel Cancer Association and
the Breast Cancer Research Foundation (BCRF), NY. NNPIO: the Russian Foundation
for Basic Research (grants 17-00-00171, 18-515-45012 and 19-515-25001). NRG Oncology: U10 CA180868, NRG SDMC grant U10 CA180822, NRG Administrative
Office and the NRG Tissue Bank (CA 27469), the NRG Statistical and Data Center (CA
37517) and the Intramural Research Program, NCI. OSUCCG: Ohio State University
Comprehensive Cancer Center. PBCS: supported by the “Fondazione Pisa per la
Scienza, project nr. 127/2016. Maria A Caligo was supported by the grant: “n. 127/16
Caratterizzazione delle varianti missenso nei geni BRCA1/2 per la valutazione del
rischio di tumore al seno” by Fondazione Pisa, Pisa, Italy; SEABASS: Ministry of
Science, Technology and Innovation, Ministry of Higher Education (UM.C/HlR/MOHE/
06) and Cancer Research Initiatives Foundation. SMC: the Israeli Cancer Association.
SWE-BRCA: the Swedish Cancer Society. UCHICAGO: NCI Specialized Program of
Research Excellence (SPORE) in Breast Cancer (CA125183), R01 CA142996,
1U01CA161032 and by the Ralph and Marion Falk Medical Research Trust, the
Entertainment Industry Fund National Women’s Cancer Research Alliance and the
Breast Cancer research Foundation. O.I.O. is an ACS Clinical Research Professor. UCLA:
Jonsson Comprehensive Cancer Center Foundation; Breast Cancer Research
Foundation. UCSF: UCSF Cancer Risk Program and Helen Diller Family Comprehensive
Cancer Center. UKFOCR: Cancer Research h UK. UPENN: Breast Cancer Research
Foundation; Susan G. Komen Foundation for the cure, Basser Research Center for
BRCA. UPITT/MWH: Hackers for Hope Pittsburgh. VFCTG: Victorian Cancer Agency,
Cancer Australia, National Breast Cancer Foundation. WCP: B.Y.K. is funded by the
American Cancer Society Early Detection Professorship (SIOP-06-258-01-COUN) and
the National Center for Advancing Translational Sciences (NCATS), grant
UL1TR000124.https://www.gimjournal.org/am2023Genetic
J/psi production as a function of charged-particle pseudorapidity density in p-Pb collisions at root s(NN)=5.02 TeV
We report measurements of the inclusive J/ψ yield and average transverse momentum as a function of charged-particle pseudorapidity density dNch/dη in p–Pb collisions at sNN=5.02TeV with ALICE at the LHC. The observables are normalised to their corresponding averages in non-single diffractive events. An increase of the normalised J/ψ yield with normalised dNch/dη, measured at mid-rapidity, is observed at mid-rapidity and backward rapidity. At forward rapidity, a saturation of the relative yield is observed for high charged-particle multiplicities. The normalised average transverse momentum at forward and backward rapidities increases with multiplicity at low multiplicities and saturates beyond moderate multiplicities. In addition, the forward-to-backward nuclear modification factor ratio is also reported, showing an increasing suppression of J/ψ production at forward rapidity with respect to backward rapidity for increasing charged-particle multiplicity
Centrality dependence of high-pT D meson suppression in Pb-Pb collisions at 1asNN = 2.76 TeV
The nuclear modification factor, RAA, of the prompt charmed mesons D0, D+ and D 17+, and their antiparticles, was measured with the ALICE detector in Pb-Pb collisions at a centre-of-mass energy 1asNN = 2.76 TeV in two transverse momentum intervals, 5 < pT < 8GeV/c and 8 < pT < 16GeV/c, and in six collision centrality classes. The RAA shows a maximum suppression of a factor of 5\u20136 in the 10% most central collisions. The suppression and its centrality dependence are compatible within uncertainties with those of charged pions. A comparison with the RAA of non-prompt J/\u3c8 from B meson decays, measured by the CMS Collaboration, hints at a larger suppression of D mesons in the most central collisions
Elliptic flow of identified hadrons in Pb-Pb collisions at 1asNN = 2.76 TeV
The elliptic flow coefficient (v2) of identified particles in Pb-Pb collisions at 1asNN = 2.76 TeV was measured with the ALICE detector at the Large Hadron Collider (LHC). The results were obtained with the Scalar Product method, a two-particle corre- lation technique, using a pseudo-rapidity gap of | 06\u3b7| > 0.9 between the identified hadron under study and the reference particles. The v2 is reported for \u3c0\ub1, K\ub1, K0S, p+p, \u3c6, \u39b+\u39b, \u39e 12+\u39e+ and \u3a9 12+\u3a9+ in several collision centralities. In the low transverse momentum (pT) region, pT 3 GeV/c
Centrality dependence of inclusive J/\u3c8 production in p-Pb collisions at 1asNN = 5.02 TeV
We present a measurement of inclusive J/\u3c8 production in p-Pb collisions at 1asNN = 5.02TeV as a function of the centrality of the collision, as estimated from the energy deposited in the Zero Degree Calorimeters. The measurement is performed with the ALICE detector down to zero transverse momentum, pT, in the backward ( 124.46 < ycms < 122.96) and forward (2.03 < ycms < 3.53) rapidity intervals in the dimuon decay channel and in the mid-rapidity region ( 121.37 < ycms < 0.43) in the dielectron decay channel. The backward and forward rapidity intervals correspond to the Pb-going and p-going direction, respectively. The pT-differential J/\u3c8 production cross section at backward and forward rapidity is measured for several centrality classes, together with the corresponding average pT and pT2 values. The nuclear modification factor is presented as a function of centrality for the three rapidity intervals, and as a function of pT for several centrality classes at backward and forward rapidity. At mid- and forward rapidity, the J/\u3c8 yield is suppressed up to 40% compared to that in pp interactions scaled by the number of binary collisions. The degree of suppression increases towards central p-Pb collisions at forward rapidity, and with decreasing pT of the J/\u3c8. At backward rapidity, the nuclear modification factor is compatible with unity within the total uncertainties, with an increasing trend from peripheral to central p-Pb collisions
Superflares on Giant Stars
The Kepler mission identified huge flares on various stars including some of
solar type. These events are substantially more energetic than solar flares,
and so they are referred to as superflares. Even a small probability of such a
superflare on the Sun would be a menace to modern society. A flare comparable
in energy with that of superflares was observed on 24th and 25th September on
the binary HK Lac. Unlike the Kepler stars, there are observations of
differential rotation for HK Lac. This differential rotation appears to be
anti-solar. For anti-solar differential rotation, dynamo models can give
magnetic activity waves of dipole symmetry as well as quasi-stationary magnetic
configurations with quadrupole symmetry. The magnetic energy of such stationary
configurations is usually about two orders of magnitude higher than that
associated with activity waves. We believe that this mechanism could provide
sufficient energy to produce superflares on late type stars, and present some
simple models in support of this idea.Comment: 7 pages, 3 figures, 1 table. Accepted to Astronomy Reports, 2018,
Vol.62, No.
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