Virtual Pitch and Pitch Shifts in Church Bells

It is well established that musical sounds comprising multiple partials with frequencies approximately in the ratio of small integers give rise to a strong sensation of pitch even if the lowest or fundamental partial is missing—the so-called virtual pitch effect. Experiments on thirty test subjects demonstrate that this virtual pitch is shifted significantly by changes in the spacing of the constituent partials. The experiments measured pitch by comparison of sounds of similar timbre and were automated so that they could be performed remotely across the Internet. Analysis of the test sounds used shows that the pitch shifts are not predicted by Terhardt’s classic model of virtual pitch. The test sounds used were modelled on the sounds of church bells, but a further experiment on seventeen test subjects showed that changes in partial amplitude only had a minor effect on the pitch shifts observed, and that a pitch shift was still observed when two of the lowest frequency partials were removed, so that the effects reported are of general interest

Partial frequencies and Chladni’s law in church bells

The rim partials of a church bell (those with an antinode at the soundbow) generate the strike pitch or perceived note of the bell. The spacing in frequency of the higher rim partials has an important effect on the tonal quality of the bell. Investigations into the partial frequencies of 2752 bells, both bronze and steel, of a wide variety of dates, founders and sizes, show a simple and unexpected relationship between the frequencies of the rim partials. This relationship explains why attempts to tune the higher rim partials independently have failed. A modified version of Chladni’s law provides insight into the musical relationship of the partials, and predicts the partials of individual bells well, but fails to give a simple model of the spacing between the partials seen in bells with different profiles

Photoionization of Co+^{+} and electron-impact excitation of Co2+^{2+} using the Dirac R-matrix method

Modelling of massive stars and supernovae (SNe) plays a crucial role in understanding galaxies. From this modelling we can derive fundamental constraints on stellar evolution, mass-loss processes, mixing, and the products of nucleosynthesis. Proper account must be taken of all important processes that populate and depopulate the levels (collisional excitation, de-excitation, ionization, recombination, photoionization, bound-bound processes). For the analysis of Type Ia SNe and core collapse SNe (Types Ib, Ic and II) Fe group elements are particularly important. Unfortunately little data is currently available and most noticeably absent are the photoionization cross-sections for the Fe-peaks which have high abundances in SNe. Important interactions for both photoionization and electron-impact excitation are calculated using the relativistic Dirac Atomic $R$-matrix Codes (DARC) for low ionization stages of cobalt. All results are calculated up to photon energies of 45 eV and electron energies up to 20 eV. The wavefunction representation of Co III has been generated using GRASP0 by including the dominant 3d$^7$, 3d$^6$[4s, 4p], 3p$^4$3d$^9$ and 3p$^6$3d$^9$ configurations, resulting in 292 fine structure levels. Electron-impact collision strengths and Maxwellian averaged effective collision strengths across a wide range of astrophysically relevant temperatures are computed for Co III. In addition, statistically weighted level-resolved ground and metastable photoionization cross-sections are presented for Co II and compared directly with existing work.Comment: 11 pages, 8 figures and 4 table

Theory and applications of atomic and ionic polarizabilities

Atomic polarization phenomena impinge upon a number of areas and processes in physics. The dielectric constant and refractive index of any gas are examples of macroscopic properties that are largely determined by the dipole polarizability. When it comes to microscopic phenomena, the existence of alkaline-earth anions and the recently discovered ability of positrons to bind to many atoms are predominantly due to the polarization interaction. An imperfect knowledge of atomic polarizabilities is presently looming as the largest source of uncertainty in the new generation of optical frequency standards. Accurate polarizabilities for the group I and II atoms and ions of the periodic table have recently become available by a variety of techniques. These include refined many-body perturbation theory and coupled-cluster calculations sometimes combined with precise experimental data for selected transitions, microwave spectroscopy of Rydberg atoms and ions, refractive index measurements in microwave cavities, ab initio calculations of atomic structures using explicitly correlated wave functions, interferometry with atom beams, and velocity changes of laser cooled atoms induced by an electric field. This review examines existing theoretical methods of determining atomic and ionic polarizabilities, and discusses their relevance to various applications with particular emphasis on cold-atom physics and the metrology of atomic frequency standards.Comment: Review paper, 44 page

Interference effects in the photorecombination of argonlike Sc3+ ions: Storage-ring experiment and theory

Absolute total electron-ion recombination rate coefficients of argonlike Sc3+(3s2 3p6) ions have been measured for relative energies between electrons and ions ranging from 0 to 45 eV. This energy range comprises all dielectronic recombination resonances attached to 3p -> 3d and 3p -> 4s excitations. A broad resonance with an experimental width of 0.89 +- 0.07 eV due to the 3p5 3d2 2F intermediate state is found at 12.31 +- 0.03 eV with a small experimental evidence for an asymmetric line shape. From R-Matrix and perturbative calculations we infer that the asymmetric line shape may not only be due to quantum mechanical interference between direct and resonant recombination channels as predicted by Gorczyca et al. [Phys. Rev. A 56, 4742 (1997)], but may partly also be due to the interaction with an adjacent overlapping DR resonance of the same symmetry. The overall agreement between theory and experiment is poor. Differences between our experimental and our theoretical resonance positions are as large as 1.4 eV. This illustrates the difficulty to accurately describe the structure of an atomic system with an open 3d-shell with state-of-the-art theoretical methods. Furthermore, we find that a relativistic theoretical treatment of the system under study is mandatory since the existence of experimentally observed strong 3p5 3d2 2D and 3p5 3d 4s 2D resonances can only be explained when calculations beyond LS-coupling are carried out.Comment: 11 pages, 7 figures, 3 tables, Phys. Rev. A (in print), see also: http://www.strz.uni-giessen.de/~k

IMAPS Observations of Interstellar Neutral Argon and the Implications for Partially Ionized Gas

We use the absorption features from neutral argon at 1048 and 1066 A to determine interstellar abundances or their lower limits toward nine early-type stars. These features were observed with the Interstellar Medium Absorption Profile Spectrograph (IMAPS) along sight lines with low reddening and low fractional abundances of molecular hydrogen. We find that the interstellar Ar I is below its solar and B-star abundance with respect to hydrogen toward zeta Pup, gamma2 Vel and beta Cen A with (logarithmic) reduction factors -0.37+/-0.09, -0.18+/-0.10, and -0.61+/-0.12 dex, respectively. While Ar can condense onto the surfaces of dust grains in the interiors of dense clouds, it is unlikely that argon atoms are depleted by this process in the low-density lines of sight considered in this study. Instead, we propose that the relatively large photoionization cross section of Ar makes it much easier to hide in its ionized form than H. In regions that are about half ionized, this effect can lower Ar I/H I by -0.11 to -0.96 dex, depending on the energy of the photoionizing radiation and its intensity divided by the local electron density. We apply this interpretation for the condition of the gas in front of beta Cen A, which shows the largest deficiency of Ar. Also, we determine the expected magnitudes of the differential ionizations for He, N, O, Ne and Ar in the partly ionized, warm gas in the local cloud around our solar system. For the local cloud and others that can be probed by UV studies, the observed Ar I to H I ratio may be a good discriminant between two possible alternatives, collisional ionization or photoionization, for explaining the existence of partly ionized regions.Comment: 36 pages, 3 figure

Low dose effects of ethanol on suckling rats: Enzymes activity, histological alterations and growth parameters.

زمینه و هدف: غلظت های پایین اتانول می توانند از طریق جفت به جنین و از طریق شیر مادر به نوزاد تازه متولد شده منتقل شوند. این مطالعه با هدف بررسی اثرات دوزهای مختلف اتانول در طول دوره شیردهی بر تغییرات آنزیمی، بافتی و شاخص های رشد نوزادان شیرخوار در موش صحرایی انجام شد. روش بررسی: در این مطالعه تجربی، 21 سر موش صحرایی ماده بالغ نژاد ویستار به سه گروه شامل دو گروه تیمار و یک گروه شاهد تقسیم شدند. به گروه های تیمار از روز یک زایمان تا روز 24 شیردهی آب آشامیدنی به همراه اتانول با غلظت حجمی 2 و 4 درصد تجویز شد و گروه شاهد تنها به آب آشامیدنی دسترسی داشتند. از هر گروه، 9 سر نوزاد موش صحرایی 25 روزه انتخاب و فعالیت سرمی آنزیم های آلانین آمینوترانسفراز، گاماگلوتامیک ترانسفراز، آسپارتات آمینوترانسفراز، آلکالین فسفاتاز، لاکتات دهیدروژناز، کراتین فسفوکیناز، نیتروژن اوره خون و کراتینین اندازه گیری شدند. همچنین مطالعات آسیب شناسی بر روی بافت های مغز، کبد و کلیه انجام شد. داده ها به کمک آزمون های آماری آنالیزواریانس و تست دانت در نرم افزار SPSS تجزیه و تحلیل شدند. یافته ها: در گروه های تجربی میزان فعالیت سرمی آنزیم های آلانین آمینوترانسفراز، آسپارتات آمینوترانسفراز، نیتروژن اوره خون، کراتین فسفوکیناز و آلکالین فسفاتاز اختلاف معنی داری را نسبت به گروه شاهد نشان ندادند (05/0P). مطالعات هیستوپاتولوژیک آسیب های مختلفی را در بافت مغز، کبد و کلیه نوزادان در معرض اتانول 4 حجمی را نشان داد. نتیجه گیری: بر اساس نتایج این مطالعه، مصرف نوشیدنی های الکلی در دوران شیردهی می تواند ضایعات جبران ناپذیری بر روی نوزاد داشته باشد

UV Absorption Lines from High-Velocity Gas in the Vela Supernova Remnant: New insights from STIS Echelle Observations of HD72089

The star HD72089 is located behind the Vela supernova remnant and shows a complex array of high and low velocity interstellar absorption features arising from shocked clouds. A spectrum of this star was recorded over the wavelength range 1196.4 to 1397.2 Angstroms at a resolving power lambda/Delta lambda = 110,000 and signal-to-noise ratio of 32 by STIS on the Hubble Space Telescope. We have identified 7 narrow components of C I and have measured their relative populations in excited fine-structure levels. Broader features at heliocentric velocities ranging from -70 to +130 km/s are seen in C II, N I, O I, Si II, S II and Ni II. In the high-velocity components, the unusually low abundances of N I and O I, relative to S II and Si II, suggest that these elements may be preferentially ionized to higher stages by radiation from hot gas immediately behind the shock fronts.Comment: 11 pages, 2 figures, Latex. Submitted for the special HST ERO issue of the Astrophysical Journal Letter