1,269 research outputs found
In situ investigations on the respiration and behaviour of the eelpout Zoarces viviparus under short-term hypoxia
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
We study an exact asymptotic behavior of the Witten-Reshetikhin-Turaev
invariant for the Brieskorn homology spheres 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 . 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
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
This paper exploits the connection between the quantum many-particle density
of states and the partitioning of an integer in number theory. For 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 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
[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)(+)βHe 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
Electronic absorptions of C<sub>5</sub><sup>+</sup> detected in the visible through action spectroscopy in a cryogenic trap
Challenges to Political Campaigns in the Media: Commercialization, Framing, and Personalization
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
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
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 β Hen with n = 1β4. The results indicate a linear shift of βΌ 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 2β3 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
ΠΠ°ΠΊΠΎΠ½ΠΎΠΌΠ΅ΡΠ½ΠΎΡΡΠΈ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΡ ΠΊΠΎΡΡΡΠΈΡΠΈΠ΅Π½ΡΠ° Π΄ΠΈΠ½Π°ΠΌΠΈΡΠ½ΠΎΡΡΠΈ Π² Π»ΠΈΠ½ΠΈΠΈ ΠΏΡΠΈΠ²ΠΎΠ΄Π° ΠΏΡΠΎΠΊΠ°ΡΠ½ΠΎΠΉ ΠΊΠ»Π΅ΡΠΈ Π² ΠΏΡΠΎΡΠ΅ΡΡΠ΅ Π΅Ρ ΡΠ°Π±ΠΎΡΡ
ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΠΏΡΠΎΡΠ΅ΡΡΠ΅ ΡΠ°Π±ΠΎΡΡ ΠΊΠ»Π΅ΡΠΈ ΠΊΠΎΡΡΡΠΈΡΠΈΠ΅Π½Ρ Π΄ΠΈΠ½Π°ΠΌΠΈΡΠ½ΠΎΡΡΠΈ Π½Π° ΡΠΏΠΈΠ½Π΄Π΅Π»ΡΠ½ΠΎΠΌ ΠΈ ΠΌΠΎΡΠΎΡΠ½ΠΎΠΌ ΡΡΠ°ΡΡΠΊΠ°Ρ
ΠΏΠ΅ΡΠΈΠΎΠ΄ΠΈΡΠ΅ΡΠΊΠΈ ΡΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎ ΠΈΠ·ΠΌΠ΅Π½ΡΠ΅ΡΡΡ Π·Π° ΡΡΠ΅Ρ ΠΈΠ·Π½ΠΎΡΠ° ΡΠΎΡΠ»Π΅Π½ΡΠ΅ΠΌΡΡ
ΡΠ»Π΅ΠΌΠ΅Π½ΡΠΎΠ² ΠΈ ΡΠ°Π·Π²ΠΈΡΠΈΡ Π·Π°Π·ΠΎΡΠΎΠ². Π£ΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½Π½ΡΠ΅ Π·Π°ΠΊΠΎΠ½ΠΎΠΌΠ΅ΡΠ½ΠΎΡΡΠΈ
ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡ ΠΏΡΠΎΠ³Π½ΠΎΠ·ΠΈΡΠΎΠ²Π°ΡΡ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΡΠ΅ Π΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΈΠ΅ Π½Π°Π³ΡΡΠ·ΠΊΠΈ Π² Π»ΠΈΠ½ΠΈΠΈ
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