1,269 research outputs found

    In situ investigations on the respiration and behaviour of the eelpout Zoarces viviparus under short-term hypoxia

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    Respiration and activity of eelpouts Zoarces viviparus L. were measured in an underwater respiration chamber in Kiel Bay (Germany) under short-term hypoxia. Respiration and swimming activity both declined almost continuously with decreasing oxygen saturation..

    On the Quantum Invariant for the Brieskorn Homology Spheres

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    We study an exact asymptotic behavior of the Witten-Reshetikhin-Turaev invariant for the Brieskorn homology spheres Ξ£(p1,p2,p3)\Sigma(p_1,p_2,p_3) by use of properties of the modular form following a method proposed by Lawrence and Zagier. Key observation is that the invariant coincides with a limiting value of the Eichler integral of the modular form with weight 3/2. We show that the Casson invariant is related to the number of the Eichler integrals which do not vanish in a limit Ο„β†’N∈Z\tau\to N \in \mathbb{Z}. Correspondingly there is a one-to-one correspondence between the non-vanishing Eichler integrals and the irreducible representation of the fundamental group, and the Chern-Simons invariant is given from the Eichler integral in this limit. It is also shown that the Ohtsuki invariant follows from a nearly modular property of the Eichler integral, and we give an explicit form in terms of the L-function.Comment: 26 pages, 2 figure

    Synthesis and Spectroscopy of Buckminsterfullerene Cation C<sub>60</sub><sup>+</sup> in a Cryogenic Ion Trapping Instrument

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    The assignment of several diffuse interstellar bands in the near-infrared to C60+ ions present at high abundance in space has renewed interest in the astrochemical importance of fullerenes and analogues. Many of the latter have not been produced in macroscopic quantities, and their spectroscopic properties are not available for comparison with astronomical observations. An apparatus has been constructed that combines laser vaporisation synthesis with spectroscopic characterisation at low temperature in a cryogenic trap. This instrument is used here to record the electronic absorptions of C60+ produced by laser vaporisation of graphite. These are detected by (helium tagged) messenger spectroscopy in a cryogenic trap. By comparison with spectra obtained using a sublimed sample of Buckminsterfullerene, the observed data show that this isomer is the dominant C60+ structure tagged with helium at m/z=724, indicating that the adopted approach can be used to access the spectra of other fullerenes and derivatives of astrochemical interest

    On the Quantum Density of States and Partitioning an Integer

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    This paper exploits the connection between the quantum many-particle density of states and the partitioning of an integer in number theory. For NN bosons in a one dimensional harmonic oscillator potential, it is well known that the asymptotic (N -> infinity) density of states is identical to the Hardy-Ramanujan formula for the partitions p(n), of a number n into a sum of integers. We show that the same statistical mechanics technique for the density of states of bosons in a power-law spectrum yields the partitioning formula for p^s(n), the latter being the number of partitions of n into a sum of s-th powers of a set of integers. By making an appropriate modification of the statistical technique, we are also able to obtain d^s(n) for distinct partitions. We find that the distinct square partitions d^2(n) show pronounced oscillations as a function of n about the smooth curve derived by us. The origin of these oscillations from the quantum point of view is discussed. After deriving the Erdos-Lehner formula for restricted partitions for the s=1s=1 case by our method, we generalize it to obtain a new formula for distinct restricted partitions.Comment: 17 pages including figure captions. 6 figures. To be submitted to J. Phys. A: Math. Ge

    Electronic Spectroscopy of Monocyclic Carbon Ring Cations for Astrochemical Consideration

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    [Image: see text] Gas phase electronic spectra of pure carbon cations generated by laser vaporization of graphite in a supersonic jet and cooled to below 10 K and tagged with helium atoms in a cryogenic trap are presented. The measured C(2n)(+)–He with n from 6 to 14, are believed to be monocyclic ring structures and possess an origin band wavelength that shifts linearly with the number of carbon atoms, as recently demonstrated through N(2) tagging by Buntine et al. (J. Chem. Phys.2021, 155, 21430234879679). The set of data presented here further constrains the spectral characteristics inferred for the bare C(2n)(+) ions to facilitate astronomical searches for them in diffuse clouds by absorption spectroscopy

    Challenges to Political Campaigns in the Media: Commercialization, Framing, and Personalization

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    Due to an increasing interdependence between mass communication and political processes, the role of media in political campaigns generated much debate.In this paper, we identify commercialization, framing and personalization as three key challenges to the way the media face political campaigns. We theoretically derive three hypotheses, one for each of those challenges. Based on data from expert interviews as well as from a content analysis, the validity of each hypothesis is surveyed. The results do not confi rm an assumed lack of providing campaign relevant news in the media coverage as proposed by considering the media as purely commercially driven organizations. Further they demonstrate the use of different frames for the presentation of competing positions in a political debate. Finally, personalization appears as an important strategy of news selection, focusing on a small number of prominent actors

    Quantum Invariants, Modular Forms, and Lattice Points II

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    We study the SU(2) Witten--Reshetikhin--Turaev invariant for the Seifert fibered homology spheres with M-exceptional fibers. We show that the WRT invariant can be written in terms of (differential of) the Eichler integrals of modular forms with weight 1/2 and 3/2. By use of nearly modular property of the Eichler integrals we shall obtain asymptotic expansions of the WRT invariant in the large-N limit. We further reveal that the number of the gauge equivalent classes of flat connections, which dominate the asymptotics of the WRT invariant in N ->\infinity, is related to the number of integral lattice points inside the M-dimensional tetrahedron

    Electronic Spectroscopy of He@C60+ for Astrochemical Consideration

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    The electronic spectrum of the endohedral fullerene He@C+60 observed by messenger spectroscopy in a cryogenic ion trap is presented. The role played by the messanger tag in the adopted experimental method is evaluated by recording spectra of He@C+60 βˆ’ Hen with n = 1βˆ’4. The results indicate a linear shift of ∼ 0.7 Γ… in the wavelengths allowing accurate gas phase values to be reported. The presence of the helium inside the cage shifts the absorption bands by 2βˆ’3 Γ… toward shorter wavelengths compared to C+60. The magnitude of this displacement will enable searches for the spectral signatures of this fullerene analogue in interstellar environments by absorption spectroscopy. The implications for potential astronomical detection are discussed

    ЗакономСрности измСнСния коэффициСнта динамичности Π² Π»ΠΈΠ½ΠΈΠΈ ΠΏΡ€ΠΈΠ²ΠΎΠ΄Π° ΠΏΡ€ΠΎΠΊΠ°Ρ‚Π½ΠΎΠΉ ΠΊΠ»Π΅Ρ‚ΠΈ Π² процСссС Π΅Ρ‘ Ρ€Π°Π±ΠΎΡ‚Ρ‹

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    Показано, Ρ‡Ρ‚ΠΎ процСссС Ρ€Π°Π±ΠΎΡ‚Ρ‹ ΠΊΠ»Π΅Ρ‚ΠΈ коэффициСнт динамичности Π½Π° шпиндСльном ΠΈ ΠΌΠΎΡ‚ΠΎΡ€Π½ΠΎΠΌ участках пСриодичСски сущСствСнно измСняСтся Π·Π° счСт износа сочлСняСмых элСмСнтов ΠΈ развития Π·Π°Π·ΠΎΡ€ΠΎΠ². УстановлСнныС закономСрности ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡŽΡ‚ ΠΏΡ€ΠΎΠ³Π½ΠΎΠ·ΠΈΡ€ΠΎΠ²Π°Ρ‚ΡŒ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡŒΠ½Ρ‹Π΅ динамичСскиС Π½Π°Π³Ρ€ΡƒΠ·ΠΊΠΈ Π² Π»ΠΈΠ½ΠΈΠΈ ΠΏΡ€ΠΈΠ²ΠΎΠ΄Π°
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