Cosmo-pl

cosmo-pl@cosmo.torun.pl

120 discussions

sf2a : vos dernieres nouvelles (fwd)
by Boud Roukema 16 Apr '08

16 Apr '08

hi cosmo-pl, A few interesting (last minute!) conference annoncements, and one (ASTRONET) which is for people willing to invest time in astropolitics (grants, long term big ground or space telescope projects). pozdr boud > ---------- Forwarded message ---------- > Date: Tue, 8 Apr 2008 18:25:10 +0200 > ... SF2A cesr fr > > Message SF2A No 337 - 8/04/08 > Sur le web: http://www.sf2a.asso.fr/spip.php?article108 > --------------------------------------------------------------------------- > 5. Rencontres de Blois: Challenges in Astroparticle Physics (18-23 mai) > --------------------------------------------------------------------------- > > Sujet: Colloque international sur les derniers resultats et projets > dans le domaine d'Astroparticules. > > Le colloque sera un melange de papiers invites, et de contributions, > sur tout aspect, theorique et experimental, des astroparticules, de > l'astronomie gamma et de l'astronomie neutrino. > > Les contributions de jeunes chercheurs sont particulierement bienvenues. > > Transmis par Ludwik Celnikier international conference on the latest results and projects in astroparticles - a mix of invited papers, contributions on theoretical and experimental aspsects of astroparticles, gamma astronomy and neutrino astronomy http://blois.in2p3.fr/2008/ - deadline yesterday! > --------------------------------------------------------------------------- > 6. Dark Energy and Dark Matter: Observations, Experiments and Theories > --------------------------------------------------------------------------- > > The Centre de Recherche Astrophysique de Lyon (CRAL) and Institut de > Physique Nucleaire de Lyon (IPNL) are making the second announcement > for the second international conference in the CRAL/IPNL Conference > Series: "Dark Energy and Dark Matter: Observations, Experiments and > Theories" to be held July 7-11, 2008 in the city of Lyon, France. > > Registration and abstract submission is open and the deadline has been > extended to April 25, 2008. The full scientific rational and many > more information are available on: http://cralconf.univ-lyon1.fr/2008 > > Transmis par Antoine Bouchard > --------------------------------------------------------------------------- > 8. The Early Phase of Star Formation (date limite 1er mai) > --------------------------------------------------------------------------- > > Second announcement of the conference EPoS 2008: The Early Phase of > Star Formation 2008 - The Future of the Field > > The Early Phase of Star Formation 2008 - The Future of the Field > July 28 - August 1, 2008 > Max-Planck Society Conference Center Ringberg Castle, Germany > Registration Deadline: ***** 1st of May, 2008 ***** > Organized by J. Steinacker & A. Bacmann > > The conference focuses on early low- and high-mass star formation. > > The topics covered are:triggered star formation, clustered star > formation, cores, chemistry, collapse, fragmentation, jets, > competitive accretion, giant molecular clouds, binarity, magnetic > fields, initial mass function, turbulence, and early phases of disks. > > EPoS 2008 aims to explore the future of the field. Special attention > will be paid to the observational and theoretical perspectives > promising substantial progress in the field. More information & > registration: http://www.mpia.de/homes/stein/EPoS2008/ > > Transmis par Aurore Bacmann > --------------------------------------------------------------------------- > 7. ASTRONET Symposium - Second Announcement > --------------------------------------------------------------------------- > > Registration is now open for the ASTRONET Infrastructure Roadmap > Symposium to be held in Liverpool, U.K. on the dates of 16-19 June > 2008. > > Further information can be obtained at: http://www.astro.livjm.ac.uk/~airs2008/ > > IMPORTANT DEADLINES > * Application for financial support: 30 April 2008 > * Abstract Submission: 23 May 2008 > * Registration: 29 May 2008 > > REGISTRATION > > Registration for the symposium can be made online through the > following website: http://www.ljmu.ac.uk/conferences/93776.asp > Registration is free of charge and covers the cost of the venue, > coffee breaks and lunches, and the conference dinner and other social > events. Please note that the number of participants will be capped at > 400. Register early to avoid disappointment. > > FINANCIAL SUPPORT > > Limited funds will be available for supporting participants from less > privileged European countries and/or at the early stages of their > careers. More details on eligibility and how to apply are available > at: http://www.astro.livjm.ac.uk/~airs2008/Support.html. > > ABSTRACTS > > This meeting will focus specifically on the first draft of the > ASTRONET Infrastructure Roadmap, which will be made publicly available > by the beginning of May 2008. We now invite short contributions on > facilities and infrastructures within the following themes related to > the Infrastructure Roadmap: > > * High energy astrophysics, astroparticle physics and gravitational waves > * UVOIR and radio/mm facilities > * Solar telescopes, solar system missions, laboratory studies > * Theory, computing facilities and networks, Virtual Observatory > * Education, recruitment and training, public outreach, industrial links > > The principal aim of this call is to obtain feedback on the ASTRONET > Infrastructure Roadmap prior to its final publication in the Autumn of > 2008. In order to submit an abstract you must register in the first > instance. You will then receive an email with further instructions. > > ACCOMMODATION > > Please book your accommodation as soon as possible after you have > registered. We are aware of at least one other large conference is > being held in the exact same venue and period of time. Thus, demand > for accommodation in the immediate vicinity of the Arena and > Convention Centre (ACC) Liverpool will almost certainly be very > high. Leaving your booking until late may result in a longer journey > to the ACC Liverpool each day. > > Transmis par Jean-Marie Hameury

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http://arxiv.org/abs/0708.0530
by Bogusław Broda 08 Feb '08

08 Feb '08

Compilation of various pieces of original remarks and answers ============================================== REMARK: ... the cosmological constant with its usual Planck scale value is present in Eq. 11 of the manuscript. Then, in going on to Eq. 24, a subtraction is introduced (the square root of the metric determinant is replaced by the square root minus one). This constitutes the usual ad hoc subtraction of the bare cosmological constant. ANSWER: ... at first sight, the subtraction could seem ad hoc, but it is not quite so. (i) Standard argument: it follows from generally accepted rules of quantum field theory, e.g. in the path-integral formalism it corresponds to a normalization of measure; (ii) Our argument: the "one" (constant) corresponds to a contribution without any external lines, i.e. it does not influence external fields by construction, and therefore it should be excluded. REMARK: Following Eq. 24, the expression is expanded about the present time, and a residual is obtained which vanishes today but which has a similar time-dependence as that of dark energy. Hence, a connection with dark energy is postulated. However, the expansion about a fixed time does not make sense. There is nothing special about the present time which allows a subtraction to be linked with the present time. ANSWER: In principle, we could expand about any fixed time. It is only a technical assumption. But to obtain present experimental values (e.g. density) we should use present experimental data (e.g. the present Hubble constant). REMARK: The purpose of this paper is to derive the contribution to the vacuum energy of the universe from the single loop of a free quantum matter field, in order to achieve better understanding of the cosmological constant problems. Needless to say that this calculation has been approached previously in many different ways. Authors adopt a very simple approach and postulate that the mentioned quantum loop should be cut-off at the Planck scale. Then, using the Schwinger-DeWitt expansion and taking only the massless scalar field case they notice that only the a0 coefficient gives contribution to the proper cosmological constant. Furthermore, they notice that making the expansion of the metric around the flat background, the first order term can be eliminated by the coordinate transformation and therefore end up with the second order term which is a product of the squares of the Hubble parameter H and the cut-off parameter, that is the Planck mass. As a result they arrive at the induced cosmological constant which has a ”correct” order of magnitude. ANSWER: Ideologically, our work consists of two parts. The first part presents the very idea, whereas the second part presents a realization of that idea. We do not insist that the realization proposed is the best and final one. REMARK: Despite the above scheme looks appealing, it has obvious weak points. For instance, if authors incorporate the field with the mass M, the next Schwinger-DeWitt term a_1 will produce contribution which will be a product of the squares of the mass M and the Planck mass. Indeed, even for neutrino this contribution will be 60 orders of magnitude greater than the ”correct” value. The origin of this occurences is that the scheme suggested by the authors is not correct from the quantum field theory viewpoint. In fact, after the effective action is calculated, one can not perform the expansion around the flat background, because the cosmological constant term should be covariant, exactly as other terms in the effective action of gravity. The explanation of the coordinate dependence of the linear in H term is that the effective action of gravity is covariant and therefore can not include terms which are odd in metric derivatives. The discussion of this point has been given recently in gr-qc/0801.0216, where one can also find many other references on the subject. ANSWER: A massive field with the mass M poses a problem. We can propose the following two independent solutions of that problem: a “theoretical” and a “technical” one. The “theoretical” solution would assume, rather a widely accepted idea, that the mass of a particle is not a fundamental entity but rather a derived one. In principle, all masses in the standard model are generated via the Higgs mechanism. According to this point of view we could legitimately assume that all masses should be neglected at this stage. The “technical” solution instead would order us to treat the M^2 part of the a_1 coefficient analogously to the a_0 coefficient. In fact, functional dependence on metric field, and only metric dependence matters, in the both terms is identical. The only difference resides in coefficients and consists in different powers of M and s (UV cutoff), i.e. we have M^0 s^-2 and M^2 s^-1, respectively. Therefore, actually the contribution of M^2 part of a_1 would be even less than that of a_0. REMARK: ... the cosmological constant problem is much deeper than the conflict between the calculation based on the Planck cut-off and the observable value. At the first place this problem involves the fine-tuning between the induced and vacuum components of the cosmological constant, as it is explained, e.g., in [2]. ANSWER: Firstly, the huge value of the vacuum energy density is a very annoying feature in itself, and, it seems, it is desirable to explain it somehow, independently of the further issue of the cosmological constant. Secondly, there is an old and a bit controversial idea of induced gravity. Intriguingly, it appears that it also yields a correct order of magnitude of the coefficient in front of the Hilbert–Einstein gravitational action. But one of the arguments against that idea says that the huge value of the cosmological constant invalidates the very idea, at least in its Sakharov’s version (demand one-loop dominance in Visser’s classification [7]), i.e. when there are only induced terms, without bare ones. Now, the tamed cosmological term and the Hilbert–Einstein gravitational action with the purely induced coefficient (only) of a correct order of magnitude, both would fit the Sakharov’s version of induced gravity idea consistently.

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http://arxiv.org/abs/0708.0530
by Bogusław Broda 08 Feb '08

08 Feb '08

Dear Colleagues, I have been suggested to comment on the paper http://arxiv.org/abs/0708.0530 . Since I am one of the authors my opinion sounds: Had we have some doubts we would not have posted the paper. Anyway, it is not a conference proceedings, and we are going to publish it. I would be very glad to hear your opinion. All your comments are welcome. In the meantime, several persons have expressed their various opinions, positive as well as criticizing. Positive opinions, "an interesting idea" or something like that, are, as usual, short. A compilation of various original critical remarks and answers I will post shortly, and it is the only thing I can do at this moment. Regards, Bogusław Broda

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DE+DM conference in Lyon (France) 7-11 July 2008 [fwd from sf2a]
by Boud Roukema 08 Feb '08

08 Feb '08

witam >From the SF2A (French astro society). pozdr boud > ---------- Forwarded message ---------- > Date: Mon, 28 Jan 2008 14:05:27 +0100 > From: SF2A... > --------------------------------------------------------------------------- > 9. Dark Energy and Dark Matter: First announcement of the CRAL/IPNL 2008 > conference > --------------------------------------------------------------------------- > The Centre de Recherche Astrophysique de Lyon (CRAL) and Institut de > Physique Nucléaire de Lyon (IPNL) are proud to announce the second > international conference in the CRAL/IPNL Conference Series: > "Dark Energy and Dark Matter: Observations, Experiments and Theories" > to be held July 7-11, 2008 in the beautiful city of Lyon, France. > http://cralconf.univ-lyon1.fr > > The conference will cover the following main themes (see further for > the full rationale): > - Dark Energy: > * Cosmology by Distance > * CMB, Large Scale Structures and Baryon Acoustic Oscillations > * Cosmology by the Growth of Structure > * Relativistic Cosmology > - Dark Matter: > * Astrophysical Evidence for Dark Matter > * Theoretical Candidates and Models for Dark Matter > * Direct and Indirect Searches for Particle Dark Matter > > Reviewers and invited speakers include: > * Elena Aprile > * Alain Blanchard > * George Ellis > * Kathy Freese > * Syksy Rasanen > * Subir Sarkar > * Carlo Schimd > * Brian Schmidt > * Dominik Schwarz > > Registration will open on February 4 2008 and we encourage you to apply > early. See our web site : http://cralconf.univ-lyon1.fr for information > and registration. > > Transmis par The Local Organizing Committee > > ---------------------------------------------------------------------- >

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Spotkanie Sieci Cz-A-K (fwd)
by Boud Roukema 15 Jan '08

15 Jan '08

witam cosmo-pl, Zapomnia³em to forwardowaæ wcze¶niej do listy, przepraszam... pozdr boud > > ---------- forwarded message ---------- > Date: Thu, 10 Jan 2008 19:52:57 +0100 (CET) > From: Tok Warsaw ... > To: Boud Roukema: ; > Subject: Spotkanie Sieci Cz-A-K > > Szanowni Panstwo, > > serdecznie zapraszamy czlonkow naszej Sieci do udzialu w warsztatach ``Particles > and Cosmology'' organizowanych przez Katedre Teorii Czastek i Oddzialywan > Elementarnych UW w ramach projektu > Transfer of Knowledge (ToK): > ``Particle Physics and Cosmology: the Interface'' (strona web > http://www.fuw.edu.pl/~tok/). Warsztaty rozpoczna sie w srode 13go lutego 2008 a > zakonczy w sobote 16go lutego 2008. > W czwartek 14go lutego, w ramach warsztatow, poczawszy od > 14:30 planujemy 8-9 20-minutowych > wystapien przedstawicieli instytucji zrzeszonych w Sieci. > Tego dnia wieczorem, po wysluchaniu referatow, mogloby sie odbyc > spotkanie polskich uczestnikow warsztatow. > > Prosimy o pilne, do 15go stycznia 2008, przesylanie zgloszen, w tym tytulow > prezentacji (w jezyku angielskim). > > Trwa proces rozpatrywania naszej aplikacji. Zostala ona przyjeta pod wzgledem > formalnym bez zadnych zastrzezen ani poprawek. > > Serdecznie pozdrawiamy, > Stefan Pokorski, Krzysztof Meissner i Zygmunt Lalak >

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conferences: XMM kwietnia 2008, Moriond-Cosmo marzec 2008 (fwd)
by Boud Roukema 30 Nov '07

30 Nov '07

> ---------- Forwarded message ---------- > Date: Fri, 30 Nov 2007 16:24:47 +0100 (CET) > From: Programme National de Cosmologie <pnc... > To: Programme National de Cosmologie <pnc... > Subject: [iso-8859-1] Diffusion PNC - mess. n° 303 > > ----------------------------------------------------------------------- > PNC PNC PNC http://www2.iap.fr/pnc/ PNC PNC PNC PNC > ----------------------------------------------------------------------- > message # 303 30 Nov. 2007 > > 1) Atelier XMM ? Paris du 14 au 16 avril 2008 > > 2) Moriond 2008 Cosmology > ----------------------------------------------------------------------- > PNC PNC PNC http://www2.iap.fr/pnc/ PNC PNC PNC PNC > ----------------------------------------------------------------------- > 1) Atelier XMM ? Paris du 14 au 16 avril 2008 > > Dans le cadre des projets de la 2eme decenie d'XMM, un atelier > international se tiendra a Paris du 14 au 16 avril 2008. > Le but de cette rencontre est d'examiner les arguments scientifiques > et la faisabilite d'un survey de ~ 100 deg2 avec XMM. > Une large place sera aussi faite a l'etude de surveys associes en > optique, SZ, IR, UV et radio. > - les propositions de contributions sont attendues pour le 15 janvier > 2008 - 2nd decade of XMM - workshop 14-16 April 2008 - Is a 200 sq.deg. survey with XMM feasible and scientifically worth it? - association with optical, SZ, IR, UV, radio surveys - deadline for contributions 15 Jan 2008 > Site web > http://www.astro.ulg.ac.be/RPub/Colloques/XXL/index.html > > Renseignements > marguerite.pierre at cea fr > ----------------------------------------------------------------------- > PNC PNC PNC http://www2.iap.fr/pnc/ PNC PNC PNC PNC > ----------------------------------------------------------------------- > 2) Moriond 2008 Cosmology > > The next Rencontres de Moriond meeting devoted to Cosmology > will be organized in La Thuile (Valle d'Aosta, Italy), > March 15-22, 2008. > > Registration is open on http://moriond.in2p3.fr/J08/ > where more details can be found (including abstract submission) > > The main topics covered in the conference will be : > > A. Dark Energy > + Cosmological probes (Reviews, experimental results > and/or new projects) > Type Ia Supernovae > Weak Lensing > Baryon Acoustic Oscillations > Galaxy Clusters: Deep Surveys > Future Projects > + Dark Energy Models and the Cosmological Constant > > B. Dark Matter > + Dark matter in galaxies and clusters of galaxies > + Gravitational lensing and dark matter > + Lyalpha forest > + Dark Matter: direct searches > + Dark Matter indirect detection with galactic gamma rays > > C. Structure Formation: prediction of simulations > + Evolution of baryonic structures in large cosmological simulations and > confrontation with observations > + Cluster simulations: Estimation of uncertainties in Dark Energy > projects > > D. CMB > + Present observations > + Combining CMB with other cosmological probes > + Polarization > + Foregrounds > + R&D > > E. Theoretical Perspectives > + Dark Energy models > + Modified gravity and alternatives (MOND) > + Inflationary Model and alternatives > + Brane Cosmology > + Back reaction > + Beyond the Standard Model: Dark Matter candidates >

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Zmiana godziny spotkania Sieci 05.09.2007 na 11.00
by Jerzy Król 03 Sep '07

03 Sep '07

Szanowni Państwo, W związku z sugestiami niektórych z Państwa i w związku ze zgłoszonymi 4-ma referatami możemy rozpocząć nasze spotkanie o *godz. 11.00*. Zatem, plan Spotkania może być już sprecyzowany: 11.00 Powitanie (wzajemne) Uczestników Spotkania w Planetarium I. Referaty: 11.10 Pawel Maslanka UŁ Łódź, 'Kwantowanie teorii opisanych przez lagranżjany zawierające drugie pochodne - obszar perturbacyjny' 11.25 Janusz Garecki US Szczecin, 'Energia wszechswiatow friedmanowskich' 11.40 Boud Roukema UT Toruń, 'Do we live in a Poincare Dodecahedral Space?' 11.55 Marek Biesiada UŚ Katowice, 'Testy modeli ciemnej materii i ciemnej energii' 11.55-12.15 Przerwa na kawę II. 12.15 Dyskusja o organizacji i bieżacych sprawach Sieci- prof. Maria Krawczyk ok. 14.30 Zakończenie Obiad można zjeść na terenie Parku w jednej z pobliskich restauracji. Odnośnie dojazdu do Planetarium to, jeśli dobrze rozumiem, nikt z Państwa nie reflektuje na przejazd z IF UŚ do planetarium. Jeśli ktoś jednak chciałby skorzystać z tego dojazdu to proszę o informację. Wyjazd wtedy odbyłby się ok. godz. 10-tej. Spotkanie w sekretariacie Zakładów Fizyki Teoretycznej UŚ ul. Bankowa 14, 3-cie piętro (tel. 032 359 14 09). Dla pozostałych osób opis dojazdu z Katowic można znaleźć na stronie Planetarium http://www.planetarium.chorzow.net.pl/dojazd.html Serdecznie pozdrawiam i do zobaczenia, Jerzy Król IF UŚ Katowice

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Spotkanie Sieci Czastki-Astrofizyka 05.09.2007
by Jerzy Król 03 Sep '07

03 Sep '07

Szanowni Panstwo, Na wszelki wypadek wklejam ponownie poprzednią wiadomość od organizatorów spotkania Sieci 05.09.2007 w Planetarium. Bardzo proszę o potwierdzenie przyjazdu lub potwierdzenie niepojawienia się reprezentanta z Państwa ośrodków- uczestników Sieci. Do tej pory wiemy o przyjezdzie reprezentantów Łodzi, Szczecina, Torunia i Warszawy. Szanowni Państwo, W związku z planowanym spotkaniem Sieci "Cząstki- Astrofizyka" (5-go 09.2007 o godz 10.00) w Planetarium Śląskim w Chorzowie bardzo proszę o informacje odnośnie ew. tematów wystąpień (15 min.; do tej pory mamy zgłoszenia tematów od prof. J. Gareckiego, prof. P. Maślanki i prof. B. Roukema). Jeśli ktoś jeszcze z Państwa chciałby przenocować w hotelu UŚ w pobliżu Planetarium, proszę również o informację. Po zebraniu danych odnośnie wystąpień będziemy mogli ustalić bardziej szczegółowy harmonogram naszego spotkania, którego głównym tematem jest oczywiście dyskusja związana z organizacją Sieci, pozyskiwaniem środków i szkołą doktorantów. Planujemy rozpocząć spotkanie o 10.00 już w Planetarium, zatem jeśli ktoś z Państwa przyjedzie pociągiem do Katowic to ok. godz. 9-tej zorganizujemy przewóz samochodami z Instututu Fizyki UŚ do Planetarium. Można wtedy spotkać się w sekretariacie Zakładów Fizyki Teoretycznej UŚ ul. Bankowa 14, 3-cie piętro (tel. 032 359 14 09). Jeśli ktoś z Państwa chciałby trafić samemu to opis dojazdu z Katowic można znaleźć na stronie Planetarium http://www.planetarium.chorzow.net.pl/dojazd.html. Bardzo proszę o informację kto z Państwa chciałby jechać spod IF UŚ a kto dojedzie sam. Serdecznie pozdrawiam i dziekuje, Jerzy Krol IF US Katowice

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Re: [Cosmo-pl] Spotkanie Sieci Czastki-Astrofizyka 05.09.2007
by soltan＠camk.edu.pl 03 Sep '07

03 Sep '07

Szanowni Panstwo, z przykroscia informuje, ze nie bede mogl uczestniczyc w najblizszym spotkaniu Sieci w Planetarium. Serdecznie pozdrawiam, Andrzej Soltan CAMK

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Spotkanie Sieci Katowice 05.09.2007
by Jerzy Król 29 Aug '07

29 Aug '07

Szanowni Państwo, W związku z planowanym spotkaniem Sieci "Cząstki- Astrofizyka" (5-go 09.2007 o godz 10.00) w Planetarium Śląskim w Chorzowie bardzo proszę o informacje odnośnie ew. tematów wystąpień (15 min.; do tej pory mamy zgłoszenia tematów od prof. M. Dąbrowskiego, prof. P. Maślanki i prof. B. Roukema). Jeśli ktoś jeszcze z Państwa chciałby przenocować w hotelu UŚ w pobliżu Planetarium, proszę również o informację. Po zebraniu danych odnośnie wystąpień będziemy mogli ustalić bardziej szczegółowy harmonogram naszego spotkania, którego głównym tematem jest oczywiście dyskusja związana z organizacją Sieci, pozyskiwaniem środków i szkołą doktorantów. Planujemy rozpocząć spotkanie o 10.00 już w Planetarium, zatem jeśli ktoś z Państwa przyjedzie pociągiem do Katowic to ok. godz. 9-tej zorganizujemy przewóz samochodami z Instututu Fizyki UŚ do Planetarium. Można wtedy spotkać się w sekretariacie Zakładów Fizyki Teoretycznej UŚ ul. Bankowa 14, 3-cie piętro (tel. 032 359 14 09). Jeśli ktoś z Państwa chciałby trafić samemu to opis dojazdu z Katowic można znaleźć na stronie Planetarium http://www.planetarium.chorzow.net.pl/dojazd.html. Bardzo proszę o informację kto z Państwa chciałby jechać spod IF UŚ a kto dojedzie sam. Serdecznie pozdrawiam i dziękuję, Jerzy Król IF UŚ Katowice

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