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Rocky reefs throughout the temperate zone are dominated by large brown algae, which are major foundation species and ecosystem engineers. There is usually an ecological bottleneck at the early life stage of such algae when they are vulnerable to a wide range of stressors. A large earthquake that affected the coastline of southern New Zealand highlighted the combined effects of sudden changes to multiple stressors on large algal assemblages. In particular, the regime of temperature, sediment and light suddenly changed as the coastal platform was lifted, and sediments from the catchment occluded the light environment of nearshore waters. Here we tested the effects of these stressors on early survival and growth of 3 formerly dominant species—the fucoids Landsburgia quercifolia and Durvillaea antarctica and the laminarian Lessonia variegata—over 100 d using a culture laboratory. After 42 d, interactive effects were found for growth of all species. Decreasing light and increasing temperature had the greatest negative effect on L. variegata and D. antarctica growth. Growth was minimal at the lowest light treatment (PAR: 16 µmol m-2 s-1) for all species, but often least growth was found at the highest sediment treatment (PAR: 32 µmol m-2 s-1). L. quercifolia was resilient to increasing temperature, whereas survival and growth decreased with increasing temperature for D. antarctica and L. variegata. These results are highly suggestive of the coincident influences of major stressors on the post-earthquake marine ecosystem. These results also highlight that recovery of large brown algae following disturbance events is likely to be slow due to an increase in coastal sedimentation and extreme water temperature.

The present article describes some activities performed with high-school students in the Solar Physics course developed in a Brazilian science centre. The topics of chemical composition, temperature and stellar evolution were taught in a room totally dedicated to study of the Sun, a solar room, designed with simple and inexpensive equipment. The course strongly emphasized practical, observational and enquiry-based activities, such as estimating the solar surface temperature, observation of the visible solar spectrum, identification of solar absorption lines, and understanding how they are produced and what kind of information can be extracted from the observed spectral lines. Some of the course goals were to foster the comprehension of the key role played by spectroscopy in astrophysics, to contextualize contents with practical activities, and to allow interdisciplinary approaches including modern physics and chemistry in physics teaching.

The IR spectra of all three Si isotopes in the form of bulk single crystals (28Si with an enrichment of more than 99.9%, and 29Si and 30Si with an enrichment of more than 90%) have been studied at T = 300, 17, and 5 K in the spectral range 550–1200 cm−1. The IR active local vibrational modes (LVM) of Si-12C centered at 605 cm−1 and Si-16O-Si quasi-molecules in the region of 1136 cm−1 for all the Si isotopes, in comparison with Si possessing a natural isotopic composition, as well as their isotopic shift at 300 and 17 K, have been determined. The dependence of the shape of the antisymmetric stretching vibration band for 28Si-16O-28Si in the spectrum of 28Si on spectral resolution has been studied. The possibility of generalizing the IR spectroscopy method for the determination of carbon and oxygen impurities in Si possessing a natural isotopic composition to monoisotopic Si have been discussed.

A sensitive technique for detecting interstitial ${\mathrm{O}}_{2}$ molecules in ${\mathrm{SiO}}_{2}$ is demonstrated by measuring their infrared $\stackrel{\ensuremath{\rightarrow}}{a}X$ luminescence at 1272.2 nm under a Ti-sapphire laser excitation into the ${\mathrm{O}}_{2}\stackrel{\ensuremath{\rightarrow}}{X}b$ absorption band at 765 nm. Contrary to the case of ${\mathrm{O}}_{2}$ trapped in inert gas matrices, the visible emission of ${\mathrm{O}}_{2}$ corresponding to the direct $\stackrel{\ensuremath{\rightarrow}}{b}X$ transition is not found. Examination of different neutron- and gamma-irradiated glassy ${\mathrm{SiO}}_{2}$ and \ensuremath{\alpha}-quartz samples reveals radiation-induced interstitial oxygen molecules in concentrations between ${10}^{14}$ and ${10}^{16}{\mathrm{m}\mathrm{o}\mathrm{l}\mathrm{e}\mathrm{c}\mathrm{u}\mathrm{l}\mathrm{e}\mathrm{s}/\mathrm{c}\mathrm{m}}^{3}.$ The radiolytic ${\mathrm{O}}_{2}$ molecules in \ensuremath{\alpha}-quartz and glassy ${\mathrm{SiO}}_{2}$ experience different structural environments.

The Raman band of the stretching vibration of interstitial oxygen molecules in glassy SiO2 is found at 1548.5±1 cm−1. By comparison with the Raman spectrum of gaseous O2 (Q band at 1555.5 cm−1), the concentration of the interstitial O2 molecules in Suprasil W1 synthetic fused silica is estimated as (8±3.5)×1017 (molecules O2)/cm3. This value is further used to calibrate the intensity of the Nd-YAG laser-excited O2 a→X infrared photoluminescence band at 1272.2 nm against the intensity of the fundamental Raman bands of glassy SiO2. In this way, quantitative measurements of O2 concentrations in SiO2 down to at least ≈1016 molecules/cm3 are possible.

A highly accurate gas chromatographic analytical method has been developed for the determination of the composition of gas mixtures. It was tested using a reference gas as an example consisting of 3.5% of CO, 14% of CO2, 0.2% of propane and residual N2 intended for the use in vehicle emission measurements. The method is based on comparison measurements with samples of a calibration gas, whose composition is iteratively adapted to that of the sample investigated using a gravimetric gas mixing method. For the gas chromatographic measurement, a molecular sieve column and a polymer column are used in parallel and in isothermal operation. All gas components can be determined by a single gas chromatographic measurement, and the relative uncertainty of measurement achievable is ?0.4%.

The oxygen content of YBa 2 Cu 3 O 7−δ epitaxially grown thin films can be quantitatively evaluated from variations of the scattering efficiencies of lattice vibrations as measured by near-infrared excited Raman spectrometry. An empirical procedure allows an accurate ( δ for δ ⩽0.042), absolute and nondashdestructive measurement to be made to a spatial resolution in the micrometer range under ambient conditions, without reference measurements or special sample preparation and on a short time scale. The method is independent of kinetic ordering effects and laser-induced photoconductivity.

The complex OD stretching vibrational Raman profile of 1-propanol (OD) in the gas phase has been analysed with the aid of a quantum mechanical calculation model based on the assumption of an intramolecular interaction between the stretching vibrational and torsional motions of the OD group. An assignment of the three band components caused by rotational isomerism in the molecule has been possible. The transition of the profile from triplet to singlet structure with increasing temperature could be attributed to vibrational transitions in torsionally excited states.

This article examines the American Institute of Certified Public Accountants (AICPA) proposal to make peer reviews mandatory for all CPA firms with public clients. It is concluded that the cost associated with peer reviews are unacceptably high for small firms, and that there exists a perception gap with the public; both of which must be addressed by the AICPA for the proposal to be successful.

Ethanol-OD is a molecule which is well suited for a study of the fine structure of the OX (X = H, D) stretching vibrational profile resulting from rotational isomerism, using Raman spectrometry. The pronounced triplet structure is correctly reproduced by a quantum-mechanical calculation on the basis of interaction between the stretching and torsional motions of the OD group. As a result, the third band between the trans and gauche doublet components can be assigned to stretching vibrational transitions in torsionally excited states with τ⩾2. The temperature dependence of the profile observed between 373 and 553 K appears to be a section of a more general evolution from a doublet structure at low temperature to a singlet at high temperature, due to the decrease of the intramolecular interaction with growing torsional excitation.

This paper describes two variations of different implementations of a (255,191) RS-Coder. The RS-Code is a powerful error correction tool that is used to ensure the detection and necessary correction of errors in communication channels, in this case DVB-H (Digital Video Broadcasting for Handhelds). DVB-H is an extended standard based on DVB-T. The (255,191) RS-Code enables mobile reception on small handheld devices under changing reception conditions. Both implementations focus on VHDL (Very high speed integrated circuit hardware description language). VHDL is a high level programming language for programmable logic devices, in this case FPGAs (field programmable gate arrays). The first implementation using logic gates only is much faster. The second implementation takes care of features like "on chip RAM" and is smaller. Both implementations are discussed and compared. By changing a few parameters it is possible to generate other RS-Coders like the (204,188) RS-Coder used in DVB-T.

It has been proved with the aid of CH3F/CD3F mixtures that the remarkably large non-coincidence effect in the Raman scattering spectrum of the v3 mode of liquid methyl fluoride is due to intermolecular vibrational coupling mediated mainly by transition dipole interaction. The amount of the effect and its temperature and mole fraction dependence are - at least qualitatively - in agreement with Logan's theoretical concept. The rather different behaviour of the isotopic species and the asymmetry and narrow width of the isotropic band, however, raise new questions which require further investigations.

The isotropic OH and SH stretching vibrational Raman scattering profiles of ethanol and ethanethiol have been measured in n-alkane solution at different temperatures. The merging of the two lines with increasing temperature (particularly in the case of ethanol), corresponding to the different molecular conformations, is attributed essentially to an increase in the interconversion rate. By means of a statistical treatment of the conformational dynamics on the basis of a Markov process taking into account further possible line broadening mechanisms, the characteristic time constants of the isomerization reactions are approximately determined as (in 10-12 s) 4·4 at 293 K and 2·0 at 423 K in the case of ethanol, and 16 183 K and 5 at 333 K in the case of ethanethiol.

The Raman scattering profiles of the OH stretching vibrations of methanol, ethanol, and n-propanol in the gas phase and of ethanol in alkane solution are measured and analyzed with regard to the conformational behaviour of the molecules. — The fine structure of the profiles is largely resolved because rotational motions do not appreciably contribute to the band width as the scattering tensor is almost isotropic. In the case of ethanol, the assignment of the two sub-bands to the trans and gauche conformers follows from the intensity ratio. An assignment to the five possible conformers is proposed for the complex profile structure of propanol. A weak satellite on the high frequency wing of the methanol profile can be assigned to a vibrational transition in the first excited torsional state. — Quantitative information on the conformational dynamics can be gained from the temperature dependence of the ethanol profile observed in solution. By applying a theoretical consideration used in NMR spectrometry to explain the dependence of the spectra on molecular dynamics to the present problem on vibrational spectrometry, the following values of the trans ⇌ gauche transition rate are determined: (3.6 ± 0.6) · 1010 s−1 at 20°C and (9.0 ± 1.5) · 1010 s−1 at 137°C.

A quantum mechanical calculation was performed to explain the temperature dependence of the OH stretching vibrational Raman profile of ethanol, which mainly consists in a pronounced increase in scattering intensity on the central region between the two band components caused by rotational isomerism. Introducing the interaction between the stretching vibrational and internal rotational motions of the OH group by means of the angular dependence of the OH stretching frequency, which can be directly taken from the gauche–trans splitting of the OH band in the experimental spectrum, leads to the result that the ‘‘fill‐up’’ effect observed in the central region can be attributed to vibrational transitions between excited torsional states.

The SH Raman profile of ethanethiol has been measured as a function of temperature. A remarkable characteristic of the profile, the temperature sensitive third band in the frequency range between two main band components which are caused by rotational isomerism, is explained by means of a quantum-mechanical calculation as consisting of vibrational transitions between excited torsional states.

The dielectric-loss tangent of liquid cyclohexane, n -hexane, n -heptane and n -octane has been determined in the frequency range 4–300 cm −1 (120 GHz-9 THz) by means of power absorption measurements using rapid-scan FTS. The results agree with literature data for cyclohexane obtained with dispersive FTS and link up well with existing microwave results, corroborating the existence of a low-frequency dielectric-loss maximum with the n -alkanes. The origin of the dielectric loss of these low-loss liquids is considered to be due to relaxational processes of weak permanent dipoles and low-lying intramolecular vibrations in the case of the n -alkanes, and to interaction-induced absorption in the case of cyclohexane.

A different approach is suggested for introducing special relativity. This approach exploits the distinction between the Doppler effect for sound and for light. With the Doppler effect for sound the difference in the frequency when the observer is in motion is not the same as when the emitter is in motion. This is exhibited already in the second order for sound, but for light there is no such shift in any order. An experiment suitable for an advanced undergraduate laboratory has been designed which can detect this second‐order difference in the acoustical shift. The system oberver (microphone) or emitter (loudspeaker) is mounted on an air track and measurement is made with a specially built frequency meter. The theoretical expression for the shift was confirmed in our laboratory for speeds from 3 to 7 m/s at an emitted frequency of 40 kHz.

The application of a commercial general purpose Raman spectrometer in gas analysis is described. The total information content of the rotational Raman spectra measured with moderate resolution in connection with the linear relationship between the concentration and the power of the scattered radiation is exploited by means of a least squares fit of a linear combination of the spectra of the components to that of the mixture for determining the composition. The feasibility of the method is demonstrated for mixtures composed of CO2, O2, N2, and CO. A relative uncertainty of 1% (2% for CO, the least favourable case) can be achieved with the present equipment. Special difficulties inherent in the method and possibilities for further improvements are discussed.

MM-wave spectrometers and receivers with wide tuning bandwidths are needed for the analysis of gases as well as for radioastronomy and EMC-measurements. Up to now, broadband Fourier transform spectrometers (FTS) with a high-precision mechanical set-up and movable mirrors or narrow-band microwave spectrum analysers (MSA) with mixers for each waveguide band are used for these purposes. Divin et al. proposed a very sensitive spectrometric method with an extremly wide tuning bandwidth /1/. No mechanical tuning and no changing of mixers is necessary. The dc voltage-current characteristics of a point-contact Josephson junction is deformed by the incident radiation according to the ac Josephson effect. The spectrum of the radiation is obtained by applying an inverse Hilbert transform on the resulting deformation of the dc characteristic. First experiments were performed. A spectrum consisting of a broad single line at 600 GHz was investigated /1/ and two narrow lines at 68 and 70 GHz were observed simultaneously in /2/. A planar integrated front end, compared to the three-dimensional set-ups used in /1/ and /2/ has the following advantages: - greater tuning bandwidth - better reproducibility - integration of a planar Josephson junction, which is mechanically more stable and needs no adjustment after each temperature cycle. - reliable contacts between the components of the front end. Therefore, a mm-and sub-mm wave Josephson spectrometer with a planar integrated front end was designed and built. This is described in this paper.

It is experimentally shown that an Nb-Nb point contact Josephson junction can be used as a very sensitive spectrometer of good frequency resolution in the range of millimetre waves by applying an inverse Hilbert transform on a characteristic deformation of its I/V characteristic caused by the absorbed RF energy.

The concentration dependences of the first moments of both the isotropic and anisotropic Raman bands of the C O stretching mode ν ( 12 C O) of acetone in chemical mixtures of type [(CH 3 ) 2 CO] x –[CCl 4 ] 1− x are compared with their dependences in isotopic mixtures of type [(CH 3 ) 2 12 CO] x –[(CH 3 ) 2 13 CO] 1− x . The role of the intermolecular resonant vibrational coupling is discussed via the experimentally observable Raman non-coincidence effect, i.e. the difference in the frequency position between the anisotropic and isotropic first moments. The experimental results are in good agreement with (1) molecular dynamics simulations and Monte Carlo simulations and (2) analytical predictions within the framework of the mean-spherical approximation of the dipole–dipole interaction. With the help of [(CH 3 ) 2 13 CO] occurring at natural abundance in the chemical mixture and of [(CH 3 ) 2 13 CO] at close to infinite dilution in the isotopic mixture, we are able to separate the environmentally induced frequency shifts from the measured anisotropic and isotropic first moments, thereby isolating the frequency shifts induced just by the intermolecular resonant vibrational coupling.