21,942 research outputs found
Ill-posedness results for the (generalized) Benjamin-Ono-Zakharov-Kuznetsov equation
No full textFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Here we consider results concerning ill-posedness for the Cauchy problem associated with the Benjamin-Ono-Zakharov-Kuznetsov equation, namely, (IVP) {u(t) - Hu(xx) + u(xyy) +u(k)u(x) = 0, (x, y) is an element of R(2), t is an element of R(+), u(x, y, 0) = phi(x, y). For k = 1, (IVP) is shown to be ill-posed in the class of anisotropic Sobolev spaces H(s1, s2) (R(2)), s(1),s(2) is an element of R, while for k >= 2 ill-posedness is shown to hold in H(s1,s2) (R(2)), 2s(1) + s(2) < 3/2 - 2/k. Furthermore, for k = 2,3, and some particular values of s(1), s(2), a stronger result is also established.Here we consider results concerning ill-posedness for the Cauchy problem associated with the Benjamin-Ono-Zakharov-Kuznetsov equation, namely, (IVP) {u(t) - Hu(xx) + u(xyy) +u(k)u(x) = 0, (x, y) is an element of R(2), t is an element of R(+), u(x, y, 0) =1393943956FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2008/58892-6]CNPq [152234/2007-1]2008/58892-6152234/2007-1This paper was written when the second author had a post-doctoral position IMPA/Brazil. He gratefully acknowledges IMPA'
Paravillersia grata Kuznetsov 1978
No full textParavillersia grata Kuznetsov, 1978 (Figs. 6–9) Paravillersia grata Kuznetsov, 1978: 50, fig. 1. FIGURE 6. Paravillersia grata Kuznetsov, 1978, female: A—seta ve, B—seta sci, C—seta c 1, D—seta e 2, E—seta f 1, F—seta h 1. Supplementary description. FEMALE (Figs. 6–9). Dorsal idiosomal setae not so heavily barbed as in original description (Fig. 6), distinctly thickened distally and sparsely barbed in distal half. Setae c 1 and d 1 almost clavate. Diameter of eyes 12. Length of dorsal setae: vi 37, ve 55, sci 38, sce 45, c 1 37, c 2 20, d 1 40, d 2 40, e 1 53, e 2 43, f 1 58, h 1 44, h 2 37. Distances between setae: vi– vi 37, ve–ve 82, sci–sci 150, c 1 – c 1 140, d 1 – d 1 135, d 2 – d 2 250, e 1 – e 1 135, e 2 – e 2 205, f 1 – f 1 92. Сallosities situated very close to each other (Fig. 7 A); inner callosity bean-like, outer oval. Setae c 2 situated on humeral shield (Fig. 7 A). Length of ventral setae: 1 a 32, 1 b 28, 1 c 26, 2 b 28, 2 c 23, 3 a 31, 3 b 24, 3 c 25, 4 a 24, 4 b 20, 4 c 19, ag 1 18, ag 2 19, ag 3 18, ps 1 20, ps 2 15, ps 3 15. Gnathosoma (Fig. 7 B). Palps as in P. jamaliensis sp. nov. Rostrum of subcapitulum long, similar with that of P. j am al i e n s i s sp. nov. Setae or 1 thickened and curved. Length of subcapitular setae: m 25, n 24, or 1 13, or 2 18. Legs (Figs. 8–9). Empodial raylets weakly capitate. Leg I (Fig. 8 A). Coxae I posterodorsally with seta-like supracoxal setae (el). Setae d on tibia and (p), (tc), (ft) on tarsus represented by eupathidia. Setae d, l” on genu and d on femur distinctly thickened, baculiform, sparsely barbed. Seta k 10. Solenidion ω 21 long, finger-shaped; solenidion φ 12 long baculiform, φp attenuate, 25 long. Leg II (Fig. 8 B). Setae d on tibia, p’ and tc’ on tarsus represented by eupathidia. Setae d on genu and femur distinctly thickened, baculiform, sparsely barbed. Solenidion ω 14 long, finger–shaped; solenidion φ 20 long, attenuate. Seta k 6 long. Leg III (Fig. 9 A). Solenidion ω 6 long, baculiform; solenidion φ 18 long, attenuate. Setae d on tibia, genu and femur distinctly thickened, baculiform, sparsely barbed. Leg IV (Fig. 9 B). Solenidion ω 4 long, baculiform; solenidion φ 21 long, attenuate. Setae d on tibia, genu and femur distinctly thickened, baculiform, sparsely barbed. Material examined. Holotype female, RUSSIA: Voronezh Province, Voronezh, in litter under coniferous, 30 October 1972, coll. N.N. Kuznetsov. Type deposition. The holotype is deposited in the mite collection of the Nikita Botanical Gardence, Yalta, Crimea, Russia. Remarks. The female holotype is in rather bad condition, especially idiosoma and I provided only supplementary description because some body structures are almost invisible. The dorsal body setae are not so heavily barbed as in the original description. Setae c 2 are situated on the humeral shield instead out of the shield in the original description.Published as part of Khaustov, Alexander A., 2014, A new species of the genus Paravillersia (Acari: Prostigmata: Stigmaeidae) from Western Siberia, with supplementary description of Paravillersia grata Kuznetsov, 1978 in Zootaxa 3873 (1), DOI: 10.11646/zootaxa.3873.1.5, http://zenodo.org/record/22878
Protecting Animals 36: Author Witi Ihimaera
No full textIn this very special episode of Knowing Animals I am joined by beloved New Zealand author Witi Ihimaera. Witi has written many books featuring nonhuman animals. He offers us a non-colonial lens through which to think about the human/nonhuman relationship
Reproduction of human fibrous dysplasia of bone in immunocompromised mice by transplanted mosaics of normal and Gsalpha -mutated skeletal progenitor cells
No full textWe have isolated progenitor cells from the stromal system of the fibrous dysplastic marrow of patients with McCune-Albright Syndrome. Analysis of the Gsalpha gene from individual colonies provided direct evidence for the presence of two different genotypes within single fibrous dysplastic lesions: marrow stromal cells containing two normal Gsalpha alleles, and those containing one normal allele and an allele with an activating mutation. Transplantation of clonal populations of normal cells into the subcutis of immunocompromised mice resulted in normal ossicle formation. In contrast, transplantation of clonal populations of mutant cells always led to the loss of transplanted cells from the transplantation site and no ossicle formation. However, transplantation of a mixture of normal and mutant cells reproduced an abnormal ectopic ossicle recapitulating human fibrous dysplasia and providing an in vivo cellular model of this disease. These results provide experimental evidence for the necessity of both normal and mutant cells in the development of McCune-Albright Syndrome fibrous dysplastic lesions in bone
I Think I Am Philip K. Dick
No full textFor years, noted writer Laurence A. Rickels often found himself compared to novelist Philip K. Dickthough in fact Rickels had never read any of the science fiction writers work. When he finally read his first Philip K. Dick novel, while researching for his recent book The Devil Notebooks , it prompted a prolonged immersion in Dicks writing as well as a recognition of Rickelss own long-documented intellectual pursuits. The result of this engagement is I Think I Am: Philip K. Dick , a profound thought experiment that charts the wide relevance of the pulp sci-fi author and paranoid visionary. I Think I Am: Philip K. Dick explores the science fiction authors meditations on psychic reality and psychosis, Christian mysticism, Eastern religion, and modern spiritualism. Covering all of Dicks science fiction, Rickels corrects the lack of scholarly interest in the legendary Californian author and, ultimately, makes a compelling case for the philosophical and psychoanalytic significance of Philip K. Dicks popular and influential science fiction.Intro -- Contents -- Introjection -- Part I -- Endopsychic Allegories -- Schreber Guardian -- Belief System Surveillance -- Part II -- Deeper Problems -- Veil of Tears -- Go West -- Dick Manfred -- Timing -- Glimmung -- Part III -- Spiritualism Analogy -- Imitating the Dead -- Indexical Layer -- Ilse -- Hammers and Things -- Crucifictions -- Over There -- Martyrology -- Can't Live, Can't Live -- Lola -- Umwelt, Mitwelt, and Eigenwelt -- Outer Race -- The German Introject -- Part IV -- Materialism, Idealism, and Cybernetics -- Startling Stories -- A Couple of Years -- Android Empathy -- Homunculus and Robot -- ALL OF YOU ARE DEAD. I AM ALIVE. -- Go with the Flow -- Part V -- Room for Thought -- Caduceus -- Jump -- Still -- A Wake -- Spätwerk -- Let the Dead Be -- Play Bally -- Das Hund -- Notes -- BibliographyFor years, noted writer Laurence A. Rickels often found himself compared to novelist Philip K. Dickthough in fact Rickels had never read any of the science fiction writers work. When he finally read his first Philip K. Dick novel, while researching for his recent book The Devil Notebooks , it prompted a prolonged immersion in Dicks writing as well as a recognition of Rickelss own long-documented intellectual pursuits. The result of this engagement is I Think I Am: Philip K. Dick , a profound thought experiment that charts the wide relevance of the pulp sci-fi author and paranoid visionary. I Think I Am: Philip K. Dick explores the science fiction authors meditations on psychic reality and psychosis, Christian mysticism, Eastern religion, and modern spiritualism. Covering all of Dicks science fiction, Rickels corrects the lack of scholarly interest in the legendary Californian author and, ultimately, makes a compelling case for the philosophical and psychoanalytic significance of Philip K. Dicks popular and influential science fiction.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
Tracking School-Related Stressors in Accelerated Epigenetic Aging
No full textKuznetsov D, Weigel L, Schowe AM, Andreas A, Liu Y, Diewald M. Tracking School-Related Stressors in Accelerated Epigenetic Aging. In: Abstracts of the 54th Annual Meeting of the Behavior Genetics Association, London, UK. Behavior Genetics. Vol 54. New York: Springer; 2024: 552
Paravillersia grata Kuznetsov 1978
No full text<i>Paravillersia grata</i> Kuznetsov, 1978 <p>(Figs. 6–9)</p> <p> <i>Paravillersia grata</i> Kuznetsov, 1978: 50, fig. 1.</p> <p> <b>FIGURE 6</b>. <i>Paravillersia grata</i> Kuznetsov, 1978, female: A—seta <i>ve</i>, B—seta <i>sci</i>, C—seta <i>c</i> 1, D—seta <i>e</i> 2, E—seta <i>f</i> 1, F—seta <i>h</i> 1.</p> <p> <b>Supplementary description</b>. FEMALE (Figs. 6–9). Dorsal idiosomal setae not so heavily barbed as in original description (Fig. 6), distinctly thickened distally and sparsely barbed in distal half. Setae <i>c</i> 1 and <i>d</i> 1 almost clavate. Diameter of eyes 12. Length of dorsal setae: <i>vi</i> 37, <i>ve</i> 55, <i>sci</i> 38, <i>sce</i> 45, <i>c</i> 1 37, <i>c</i> 2 20, <i>d</i> 1 40, <i>d</i> 2 40, <i>e</i> 1 53, <i>e</i> 2 43, <i>f</i> 1 58, <i>h</i> 1 44, <i>h</i> 2 37. Distances between setae: <i>vi– vi</i> 37, <i>ve–ve</i> 82, <i>sci–sci</i> 150, <i>c</i> 1– <i>c</i> 1 140, <i>d</i> 1– <i>d</i> 1 135, <i>d</i> 2– <i>d</i> 2 250, <i>e</i> 1– <i>e</i> 1 135, <i>e</i> 2– <i>e</i> 2 205, <i>f</i> 1– <i>f</i> 1 92. Сallosities situated very close to each other (Fig. 7 A); inner callosity bean-like, outer oval. Setae <i>c</i> 2 situated on humeral shield (Fig. 7 A). Length of ventral setae: 1 <i>a</i> 32, 1 <i>b</i> 28, 1 <i>c</i> 26, 2 <i>b</i> 28, 2 <i>c</i> 23, 3 <i>a</i> 31, 3 <i>b</i> 24, 3 <i>c</i> 25, 4 <i>a</i> 24, 4 <i>b</i> 20, 4 <i>c</i> 19, <i>ag</i> 1 18, <i>ag</i> 2 19, <i>ag</i> 3 18, <i>ps</i> 1 20, <i>ps</i> 2 15, <i>ps</i> 3 15. Gnathosoma (Fig. 7 B). Palps as in <i>P. jamaliensis</i> <b>sp. nov</b>. Rostrum of subcapitulum long, similar with that of <i>P. j am al i e n s i s</i> <b>sp. nov</b>. Setae <i>or</i> 1 thickened and curved. Length of subcapitular setae: <i>m</i> 25, <i>n</i> 24, <i>or</i> 1 13, <i>or</i> 2 18. Legs (Figs. 8–9). Empodial raylets weakly capitate. Leg I (Fig. 8 A). Coxae I posterodorsally with seta-like supracoxal setae (<i>el</i>). Setae <i>d</i> on tibia and (<i>p</i>), (<i>tc</i>), (<i>ft</i>) on tarsus represented by eupathidia. Setae <i>d</i>, <i>l”</i> on genu and <i>d</i> on femur distinctly thickened, baculiform, sparsely barbed. Seta <i>k</i> 10. Solenidion <i>ω</i> 21 long, finger-shaped; solenidion <i>φ</i> 12 long baculiform, <i>φp</i> attenuate, 25 long. Leg II (Fig. 8 B). Setae <i>d</i> on tibia, <i>p’</i> and <i>tc’</i> on tarsus represented by eupathidia. Setae <i>d</i> on genu and femur distinctly thickened, baculiform, sparsely barbed. Solenidion <i>ω</i> 14 long, finger–shaped; solenidion <i>φ</i> 20 long, attenuate. Seta <i>k</i> 6 long. Leg III (Fig. 9 A). Solenidion <i>ω</i> 6 long, baculiform; solenidion <i>φ</i> 18 long, attenuate. Setae <i>d</i> on tibia, genu and femur distinctly thickened, baculiform, sparsely barbed. Leg IV (Fig. 9 B). Solenidion <i>ω</i> 4 long, baculiform; solenidion <i>φ</i> 21 long, attenuate. Setae <i>d</i> on tibia, genu and femur distinctly thickened, baculiform, sparsely barbed.</p> <p> <b>Material examined</b>. Holotype female, <b>RUSSIA</b>: Voronezh Province, Voronezh, in litter under coniferous, 30 October 1972, coll. N.N. Kuznetsov.</p> <p> <b>Type deposition</b>. The holotype is deposited in the mite collection of the Nikita Botanical Gardence, Yalta, Crimea, Russia.</p> <p> <b>Remarks</b>. The female holotype is in rather bad condition, especially idiosoma and I provided only supplementary description because some body structures are almost invisible. The dorsal body setae are not so heavily barbed as in the original description. Setae <i>c</i> 2 are situated on the humeral shield instead out of the shield in the original description.</p>Published as part of <i>Khaustov, Alexander A., 2014, A new species of the genus Paravillersia (Acari: Prostigmata: Stigmaeidae) from Western Siberia, with supplementary description of Paravillersia grata Kuznetsov, 1978 in Zootaxa 3873 (1)</i>, DOI: 10.11646/zootaxa.3873.1.5, <a href="http://zenodo.org/record/228781">http://zenodo.org/record/228781</a>
Liftings for noncomplete probability spaces
No full textThe current state of knowledge concerning liftings for noncomplete probability spaces is discussed. This is a somewhat expanded version of the author's talk given at the 1991 Summer Conference on General Topology and Applications in Honor of Mary Ellen Rudin and Her Work.PT: S; CR: BURKE MR, IN PRESS P AM MATH S BURKE MR, 1991, ISRAEL J MATH, V73, P33 BURKE MR, 1992, ISRAEL J MATH, V79, P289 CARLSON T, THEOREM LIFTING CHRISTENSEN JPR, 1974, TOPOLOGY BOREL STRUC FREMLIN DH, 1989, HDB BOOLEAN ALGEBRAS, P877 INOESCUTULCEA A, 1966, 5TH P BERK S MATH ST, V2 IONESCUTULCEA A, 1967, CONTRIBUTIONS PROB 1, P63 IONESCUTULCEA A, 1969, TOPICS THEORY LIFTIN JECH TJ, 1978, SET THEORY JOHNSON RA, 1980, P AM MATH SOC, V80, P234 JUST W, IN PRESS T AM MATH S KUPKA J, 1983, INDIANA U MATH J, V32, P717 LOSERT V, 1983, LNM, V1080, P95 MAHARAM D, 1958, P AM MATH SOC, V9, P987 SHELAH S, 1983, ISRAEL J MATH, V45, P90 TALAGRAND M, 1982, P AM MATH SOC, V84, P379 VONNEUMANN J, 1931, CRELLES J MATH, V165, P109; NR: 18; TC: 0; J9: ANN N Y ACAD SCI; PG: 4; GA: BZ86BSource type: Electronic(1
Verification of Monte Carlo transport codes by activation experiments
No full textWith the increasing energies and intensities of heavy-ion accelerator facilities, the problem of an excessive activation of the accelerator components caused by beam losses becomes more and more important. Numerical experiments using Monte Carlo transport codes are performed in order to assess the levels of activation. The heavy-ion versions of the codes were released approximately a decade ago, therefore the verification is needed to be sure that they give reasonable results. Present work is focused on obtaining the experimental data on activation of the targets by heavy-ion beams. Several experiments were performed at GSI Helmholtzzentrum für Schwerionenforschung. The interaction of nitrogen, argon and uranium beams with aluminum targets, as well as interaction of nitrogen and argon beams with copper targets was studied. After the irradiation of the targets by different ion beams from the SIS18 synchrotron at GSI, the γ-spectroscopy analysis was done: the γ-spectra of the residual activity were measured, the radioactive nuclides were identified, their amount and depth distribution were detected. The obtained experimental results were compared with the results of the Monte Carlo simulations using FLUKA, MARS and SHIELD. The discrepancies and agreements between experiment and simulations are pointed out. The origin of discrepancies is discussed. Obtained results allow for a better verification of the Monte Carlo transport codes, and also provide information for their further development. The necessity of the activation studies for accelerator applications is discussed. The limits of applicability of the heavy-ion beam-loss criteria were studied using the FLUKA code. FLUKA-simulations were done to determine the most preferable from the radiation protection point of view materials for use in accelerator components.Die Aktivierung von Beschleunigerkomponenten durch Strahlverluste ist einer der wichtigsten Faktoren der Intensitätsbegrenzung für hochenergetische und hochintensive Hadronenbeschleuniger. Erhöhte Dosisleistungen in der Nähe von bestrahlten Materialien erschweren die Hands-On-Wartung der Maschine. Deshalb ist die Aktivierung von Beschleunigerkomponenten von großem Belang für die “Facility for Antiproton and Ion Research“ (FAIR). Dies führt zur Notwendigkeit einer Messung der Restaktivität in den Tiefenschichten von bestrahlten Festkörpern.
Im Rahmen dieser Arbeit wurden Grenzen für Strahlverluste von Schwerionenstrahlen ermittelt, welche bzgl. der Zugänglichkeit einer Beschleunigeranlage zu Wartungszwecken etc. einzuhalten sind.
Der Schwerpunkt der vorliegenden Studie war die Messung der Restaktivität im Material, hervorgerufen durch Ionenstrahlen verschiedener Spezies: Stickstoff (Z = 7), Argon (Z = 18) und Uran (Z = 92). Als zu bestrahlende Materialien wurden Aluminium und Kupfer ausgewählt – als Repräsentanten für den niedrigen und mittleren Z-Bereich. Im Hinblick auf Beschleunigeranwendungen sollten Aluminiumkomponenten in den Bereichen mit hohen Strahlverlusten bevorzugt werden, da dieses Material offenbar weniger aktiviert wird als Hoch-Z-Materialien, andererseits ist Kupfer ein übliches Material für viele Beschleunigerkomponenten wie z.b. für Spulen der Magnete. Deshalb ist der Vergleich von Aluminium und Kupfer vom besonderen Interesse.
Zwei Arten von Targets wurden bestrahlt: gestapelte Folien- und Einzelfolien-Targets. Die dicken Aluminium-Targets wurden mit 498 AMeV Stickstoff 14N7+, 496 AMeV Argon 40Ar18+ und 483 AMeV Uran 238U73+, die dicken Kupfer-Targets wurden mit 498 AMeV Stickstoff und 496 AMeV Argon bestrahlt. Die dünnen Aluminium-Folien wurden mit 426 AMeV Argon und mit 85, 174, 279, 325, 381, 483, 584, 684, 785, 935 AMeV Uran bestrahlt.
Insgesamt fünf dicke und zehn Einzelfolientargets wurden für die vorliegende Doktorarbeit bestrahlt. Mehr als 5000 Spektren wurden gemessen und analysiert, 45 Tiefenprofile verschiedener Nuklide in den durchgeführten Experimenten erhalten.
Für das Design von Beamdumps und Strahlabschirmungen (und für vielfältige andere Anwendungen) verwendet man die Monte Carlo Transportcodes, welche die Bewegung und Wechselwirkung von Teilchen mit Materie berechnen. Die Schwerionen-Versionen der Monte Carlo Transportcodes wurden etwa vor fünfzehn Jahren eingeführt und sind noch nicht in allen Energie- und Z-Bereichen bestätigt. Es gibt nur wenige Daten für die Aktivierung der Materialien durch Schwerionenstrahlen.
Die Verifikation der Monte-Carlo-Codes durch Aktivierungsexperimente ermöglicht die Überprüfung von Transport und nuklearer Erzeugung explizit durch den Vergleich der Typen, der Häufigkeit und der Tiefenprofile der Radionuklide, die im bestrahlten Material erzeugt oder gestoppt werden.
In der vorliegenden Arbeit wurden die Codes FLUKA, MARS und SHIELD für die Verifizierung gewählt. Das Stoppen der Ionen mit Energien von bis zu 500 AMeV wird von allen drei Codes gut beschrieben. Gemäß den durchgeführten Experimenten und Simulationen wird die Gesamtzahl der erkannten Nuklide im gesamten Targetvolumen von FLUKA mit durchschnittlich ~ 5% Abweichung, durch MARS mit einer ~ 15%-igen Abweichung angegeben, und SHIELD unterscheidet sich um ca. 50% vom Experiment. Die erhaltenen experimentellen Ergebnisse erlauben nicht nur eine Bestätigung dieser Monte-Carlo-Transportcodes, sondern auch deren weitere Entwicklung.
Andere Ziele waren, die Grenzen der Anwendbarkeit der Schwerionenstrahlverlust- Kriterien zu erforschen und herauszufinden, welches Material in Beschleunigeranwendungen bezüglich des Strahlenschutzes zu bevorzugen ist.
Folgende Grenzen für erlaubte Strahlleistungsdepositionen entlang eines Beschleunigers wurden ermittelt:
Fall A: Nach 100 Tagen Strahlzeit soll die Maschine nach einer Wartezeit von 4 Stunden zugänglich sein. Für 50 AMeV Uranstrahlen auf Eisen wurde ein Grenzwert von 200 W/m bestimmt. Bei Verdopplung der Strahlenergie auf 100 AMeV sinkt die zulässige Strahlverlustleistung auf 60 W/m in Eisen. Tauscht man das Eisentarget gegen ein Kupfertarget aus, so sind die entsperechenden Grenzwerte 120 W/m bzw. 80 W/m.
Fall B: Nach 20 Jahren Strahlbetrieb soll die Maschine nach einer Wartezeit von wiederum 4 Stunden zugänglich sein. In diesem Fall sinken die erlaubten Strahlverlustleistugen auf 120 W/m bzw. 40 W/m in Eisen und auf 85 W/m bzw. 50 W/m in Kupfer.
Die Aktivierung derjenigen Materialien, die am häufigsten in Beschleunigern verwendet werden, wurde mit FLUKA durchgeführt. Die Dosisleistungen im Abstand von 30 cm von der Targetfläche sind am höchsten für Ni, Nb und Mo, sodass der Anteil dieser Materialien in den Beschleunigerkomponenten minimiert werden muss. Die Dosisleistungen in der Nähe der Targets aus C, Al, Ti, Cr, Mn, Fe, Cu und Pb waren mindestens zweimal niedriger; deshalb können aus Sicht der Hands-On-Wartung diese Materialien eher verwendet werden. Bei langer Bestrahlung und langer Kühlzeit zeigten Al, Ti, Mn, Ni und Cu die höchsten Dosisleistungen. Dies sollte berücksichtigt werden, wenn lange Bestrahlungszeiten vorgesehen sind und ferner eine nachfolgende Lagerung der bestrahlten Materialien erforderlich ist
Fluorpyromorphite, Pb5(PO4)3F, a new apatite-group mineral from Sukhovyaz Mountain, Southern Urals, and Tolbachik volcano, Kamchatka
No full textFluorpyromorphite, ideally Pb5(PO4)3F, a new apatite-group member, an F-dominant analog of pyromorphite and hydrox-ylpyromorphite. It is a supergene mineral found at two localities: Sukhovyaz Mountain, Ufaley District, Southern Urals (holotype) and Mountain 1004, Tolbachik volcano, Kamchatka (co-type), both in Russia. At Sukhovyaz, fluorpyromorphite forms anhedral grains up to 0.2 mm across (usually much smaller), filling cavities in quartz and sometimes partially replacing fluorapatite. Associated supergene minerals include pyromorphite, hydroxylpyromorphite, fluorphosphohedy-phane, mimetite, and nickeltsumcorite. At Tolbachik, fluorpyromorphite occurs in the oxidation zone of paleo-fumarolic deposits in close association with pyromorphite, fluorphosphohedyphane, wulfenite, cerussite, munakataite, vanadinite, chrysocolla, and opal. It forms crude long-prismatic to acicular crystals up to 0.1 mm long and up to 5 mu m thick com-bined in bunches and spherulites up to 0.2 mm. Fluorpyromorphite is colorless (Sukhovyaz) or yellow (Tolbachik), translucent to transparent and has a vitreous luster. It is brittle, with an uneven fracture and poor cleavage on (001). The calculated density values are 7.382 (holotype) and 6.831 (cotype) g/cm3. Fluorpyromorphite is optically uniaxial (-). In reflected light, it is light-grey, weakly anisotropic. The reflectance values (Rmin/Rmax, %) are: 15.8/16.6 (470 nm), 16.2/17.2 (546 nm), 15.9/16.9 (589 nm), 15.4/16.2 (650 nm). The chemical composition is (electron microprobe, wt. %; holotype/co-type): CaO 0.10/3.16, SrO 0.17/0.00, PbO 83.51/77.39, P2O516.13/16.35, CrO3 0.00/0.49, SeO3 0.00/0.98, F 1.00/1.35, Cl 0.29/0.40, H2Ocalc 0.13/0.00, -O=(F,Cl) -0.49/-0.66, total 100.84/99.46. The empirical formulae based on 13 anions (O +F + Cl+OH)pfu are Pb4.95Ca0.02Sr0.02P3.00O12F0.70(OH)0.19Cl0.11 (holotype) and Pb4.26Ca0.69P2.83Se6+0.09Cr6+0.06 O11.99F0.87Cl0.14 (co-type). Fluorpyromorphite is hexagonal, space group P63/m, unit-cell parameters (from powder X-ray diffraction data; holotype / co-type) are: a = 9.779(5) / 9.732(1), c = 7.241(9) / 7.242(1) angstrom, V = 599.6(7) / 594.0(2) angstrom 3, and Z = 2. The crystal structure was refined using the Rietveld method to Rp= 0.1764 (holotype). Fluorpyromorphite is isostructural with other members of the apatite group, a subdivision of the apatite supergroup
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