bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustics of the flute
Authors: Coltman John W.
Published: January 2009

IN THE LONG HISTORY of scientific investigation of musical instruments the flute has been given particular attention, primarily because of its apparent simplicity. Yet many of the physical factors that determine its behavior have not been well documented. In my experiments I have tried to look at some of these factors quantitatively, concentrating on a comparison of the passive resonance and blown frequencies of the flute, on the details of the blowing mechanism at the mouth hole, and on the energy conversion and losses of the instrument when it is regarded as an oscillator with a resonant circuit and nonlinear feedback. It turns out that the momentum and arrival time of waves on the blowing jet determine the loudness and pitch of the sounded note. Details of the flutist's empirically learned technique can be explained in these terms.
Magnetic fields in biology
Authors: Kolin Alexander
Published: January 2009

SUPERSTITION AND QUACKERY dominated experimentation and speculation on interaction of magnetic fields with living systems for well over a thousand years. More critical inquiry is of relatively recent origin. There is still controversy about a variety of findings, but sound observations and applications of magnetic interactions to biology and medicine are beginning to emerge. Thus, for instance, constant magnetic fields have been shown to affect plant growth and animal development, alternating magnetic fields have been used to stimulate nerves and to evoke visual sensations, and activity of nerves and muscles has been shown to be accompanied by transient magnetic fields. Most advanced is the development of magnetic methods of measurement. These methods include electromagnetic determination of blood flow and magnetic resonance spectrometry of biological molecules.
Phimsy
Authors: Ellis R. Hobart , Lighthead Felix , Freilich Theodore H.
Published: January 2009

Fingerprinting art forgeries; The Electron; When is physics too pure?; Versatility on demand; Numeroff and physics fame.
N-Galaxy Fluctuations May Settle Quasar Arguments
Authors: Scott John T.
Published: January 2009

The arguments over the distance of quasars may be resolved by observed rapid changes in brightness of some N-type galaxies. Measurements made with the 200-inch telescope at Mount Palomar are reported independently by John B. Oke and Allan Sandage (both of Cal Tech) in Astrophysical Journal 150, L5 and L9 (1967). Galaxy 3C 371 has been found to vary by about one magnitude over the last two years and by about 0.10–0.15 magnitude within a few days. Changes in its color have also been seen.
Phimsy
Authors: Ellis R. Hobart
Published: January 2009

That was physics in 1771; Name it and you've got it.
What ever happened to federal funds?
Authors: Hosmer Craig
Published: January 2009

IT HAS BEEN SAID that the way to get rich quick is to many a rich woman. But that is not the only way as the scientific community discovered early in the 1950's. Its way was to romance a rich uncle.
Acoustical measurement of violins
Authors: Hutchins Carleen M. , Fielding Francis L.
Published: January 2009

ACOUSTICAL EXAMINATIONS of the violin family extend over 200 of its more than 300 years but the instruments still defy analysis and complete understanding. The apparent simplicity of the problem is misleading; although the violin can be represented as merely a resonant air cavity in a wooden enclosure, driven by vibrating strings, the number of parameters to be determined for full analysis is very great.
Physics and the nation in a crystal ball
Authors: Branscomb Lewis M.
Published: January 2009

THE UNITED STATES appears obsessed with self-doubt concerning its ability to solve its problems in a manner consistent with its self-image. This doubt flourishes despite a revolution of far-reaching social legislation that embodies at every hand the intention to apply the power of scientific research to the solution of our problems; many of the alienated among us tend to identify our troubles with technology. They see science, and perhaps especially physics, as encouraging a mindless, mechanical approach to life that is dehumanizing our society. Yet the record shows that scientists and, I believe, particularly physicists have consistently led efforts to awaken our society to the dangers of the misuse of technology, of the arms race, of the pollution of our environment, of the choking of our transportation and the physical decay of our cities. The social conscience of the physicist is rooted in the personality of American physics. Knowing the limitations of our expertise, but sure of the soundness of our motives, we are concerned to define correctly the character of our profession and its place in the life of our society.
Muon and Electron Magnetic-Moment Anomalies Disagree with Theory
Authors: Lubkin Gloria B.
Published: January 2009

New determinations of g−2, the anomalous magnetic moment, for the muon and electron show small departures from their theoretically predicted values. The muon value, reported by Francis Farley (Royal Military College of Science, Shrivenham, UK) at the Washington APS meeting, is higher than theory. The electron value is lower, according to Arthur Rich of the University of Michigan who recently recalculated (Phys. Rev. Letters 20, 967, 1968) g−2 using the data of David T. Wilkinson and H. Richard Crane (Phys. Rev. 130, 852, 1963). New experiments to measure the election g-factor anomaly are being done by Rich and by Larry Knight of Stanford University and by G. Gräff at the Physics Institute of the University, Bonn.
Distill or drown: The need for reviews
Authors: Herring Conyers
Published: January 2009

BY NOW THERE can hardly be a physicist who has not been jolted by the challenge of the information explosion. Some men have been so overcome that they have given up subscribing to The Physical Review for lack of shelf space. The widespread concern about this challenge has been reflected in a number of recent articles in PHYSICS TODAY and in similar discussions in magazines of other fields and other countries. Among the great bulk of physicists diverse attitudes prevail: Some remain happy in a speciality narrow enough so that they can feel “in the swim” if they keep in touch with a few colleagues and read a highly specialized journal; others rationalize with the comment that most of the literature is garbage anyway; a few pin their hopes on the vast improvements being made by their documentalist colleagues in the science of indexing and retrieval.
Phimsy
Authors: Ellis R. Hobart , Mackay Alan
Published: January 2009

Integrated Circuit; That 1932 banquet picture; Does excitement make you mean?; O joyous need for jobs.
Electrons in metals
Authors: Harrison Walter A.
Published: January 2009

IT IS REMARKABLE how much of the basic description of electrons in metals was made available to us 40 years ago in the doctoral thesis of Felix Bloch. He not only explained how electrons can travel through perfect crystals without colliding with the constituent atoms, but he also discussed the scattering of those electrons when the crystal lattice is vibrating. The origin of this scattering is now called the “electron-phonon interaction,” but the calculation came some 20 or 30 years before the word “phonon” was even coined. He also evaluated the electronic contribution to the specific heat.
Needs for a national policy
Authors: Daddario Emilio Q.
Published: January 2009

THIRTY YEARS AGO research in physics in the United States was a remote concern of government. Graduate students in this then pure science were the original do-it-yourself leaders and had to become as adept at begging and borrowing as they were in making equipment. Then came the discovery of fission, the second world war and the nuclear chain reaction. You well know the rest of the story. Congress was so impressed with the enormous new power derived from the science of physics that it enacted one of the most extraordinary laws in our history—the Atomic Energy Act of 1946.
30 years of small-angle x-ray scattering
Authors: Guinier André
Published: January 2009

EXPERIMENTAL AND THEORETICAL advances in the study of x-ray diffraction at small angles both started about 30 years ago. With the focusing crystal monochromator experimenters could obtain the intensity and resolution they needed to resolve the diffraction pattern close to the primary beam. Now many other methods allow a study of this kind of scattering. And application of the form-factor concept in scattering theory provided a statistical measure for the average size and shape of the small grains that are responsible for this kind of scattering.
Acoustics
Authors: Beranek Leo L.
Published: January 2009

AN INTELLECTUALLY VITAL and stimulating field, acoustics is rich in unsolved and intriguing research problems. Its areas of interest are pertinent to the activities of many traditional university departments: mathematics, physics, electrical engineering, mechanical engineering, land and naval architecture, behavioral sciences and even biology, medicine and music.
Quasistellar objects and seyfert galaxies
Authors: Colgate Stirling A.
Published: January 2009

CONCEPTS of the size and geometry of our observable universe depend largely on what we make of the mysterious, distant quasistellar objects. Seyfert galaxies, which have a bright nucleus at the center of an otherwise normal galaxy, have been another source of mystery. Observations of their optical and radio emissions show fluctuations. If we can find a relation between quasistellar objects and Seyfert galaxies, suggesting a similar origin and an evolutionary link, we may be able to use the fluctuating emission as a new yardstick for the universe.
A Visit to the Semiconductor Institute in Leningrad
Authors: Lubkin Gloria B.
Published: January 2009

One of the leading Soviet centers for solid-state physics is the Semiconductor Institute in Leningrad, which has 170 scientists and 800 employees. When we visited the Institute shortly after attending the ninth International Conference on the Physics of Semiconductors, we talked with institute director A. R. Regel, one of the conference vice-chairmen. He told us of research and development activities and explained how the scientific soviet helps run the institute.
Phimsy
Authors: Ellis R. Hobart , Blitzstein William
Published: January 2009

Decimal time is here; Gamow gambols; Pulsars in poetry; Purcell on Dicke; A practical Peltier effect; Chicago Tribune speaks; Lasers in the kitchen.
Analysis of musical-instrument tones
Authors: Risset Jean-Claude , Mathews Max V.
Published: January 2009

POWERFUL NEW METHODS are now available for the study of tone quality of both existing and new instruments. The new methods involve both new tools (primarily computers) and new applications of experimental psychology (psychophysics and subjective judgments).
Search for Stable Elements Heavier than Uranium
Authors: Lubkin Gloria B.
Published: January 2009

Recent theoretical calculations suggest that element number 110 may live for millions of years. Researchers are looking for such a stable, superheavy element in platinum ores and cosmic rays and by heavy-ion bombardment of heavy nuclei.
Phimsy
Authors: Ellis R. Hobart
Published: January 2009

Practical surface science; We take to the air…; …and stall on the ground; The earth is still flat; Perchance to wake.
Why has he changed?
Authors: Slater John C.
Published: January 2009

FOR NEARLY A HALF CENTURY, since I started my own graduate work in 1920, I have known physics graduate students. Have they changed in that time and are the changes good or bad? What effect have marriage at an earlier age, fewer really new fields and specialization had on his attitude? Why is there less enthusiasm and proportionately fewer leaders?
Units for logarithmic scales
Authors: McCamy Calvin S.
Published: January 2009

LOGARITHMIC SCALES ARE useful in many fields. Sound power attenuation, musical pitch, star magnitudes, photographic exposure parameters, hydrogen ion concentration and optical densities are all expressed on logarithmic scales, but how different the usages appear! As each technology satisfied its need in an ad hoc manner, the systems took on various peculiar forms. As a result, the essential equivalence of the forms is not generally recognized and the concepts and terminology are usually treated as special cases.
Phimsy
Authors: Ellis R. Hobart , Slabinski Victor J. , Bernstein Barry
Published: January 2009

A console for theater sound; Decimal angle units; Rheology in poetry.
The international union of pure and applied physics
Authors: Kerwin Larkin
Published: January 2009

PHYSICISTS HAVE BEEN GROUPED for most of the century in a continuing international association, but its fortunes have been erratic, particularly during and immediately following World War I. In 1931, the International Union of Pure and Applied Physics (IUPAP) was one of eight scientific unions, including those of chemistry, biology and astronomy, doing business on a world-wide scale. The Union's purpose is to foster international physics meetings, more rapid dissemination of information and the establishment of international standards, units and nomenclature.
Processing and near-field optical properties of self-assembled plasmonic nanoparticle networks
Authors: Bonell Frédéric , Sanchot Audrey , Dujardin Erik , Péchou Renaud , Girard Christian , Li Mei , Mann Stephen
Published: January 2009

We report on recent progress in the production and the deposition on surfaces of dielectric materials of self-assembled metallic nanoparticle systems able to organize into branched networks. We emphasize the interest of these new objects for tailoring novel near-field optical properties that could be the basis for optical energy transport in systems of extremely reduced sizes. The experimental optical spectra of such chain networks in solution can be very well reproduced by applying the coupled-dipole approximation scheme. In this paper, we apply this method to investigate the near-field optical properties of self-assembled plasmonic nanoparticle networks deposited on transparent surfaces.
Adenine monolayers on the Au(111) surface: Structure identification by scanning tunneling microscopy experiment and ab initio calculations
Authors: Lukas Maya , Kelly Ross E. A. , Kantorovich Lev N. , Otero Roberto , Xu Wei , Laegsgaard Erik , Stensgaard Ivan , Besenbacher Flemming
Published: January 2009

From an interplay between scanning tunneling microscopy (STM) and ab initio density functional theory (DFT) we have identified and characterized two different self-assembled adenine (A) structures formed on the Au(111) surface. The STM observations reveal that both structures have a hexagonal geometry in which each molecule forms double hydrogen bonds with three nearest neighbors. One of the A structures, with four molecules in the primitive cell, has p2gg space group symmetry, while the other one, with two molecules in the cell, has p2 symmetry. The first structure is observed more frequently and is found to be the dominating structure after annealing. Experimental as well as theoretical findings indicate that the interaction of A molecules with the gold surface is rather weak and smooth across the surface. This enabled us to unequivocally characterize the observed structures, systematically predict all structural possibilities, based on all known A-A dimers, and provisionally optimize positions of the A molecules in the cell prior to full-scale DFT calculations. The theoretical method is a considerable improvement compared to the approach suggested previously by Kelly and Kantorovich [Surf. Sci. 589, 139 (2005)]. We propose that the less ordered p2gg symmetry structure is observed more frequently due to kinetic effects during island formation upon deposition at room temperature.
Integration of Grassmann variables over invariant functions on flat superspaces
Authors: Kieburg Mario , Kohler Heiner , Guhr Thomas
Published: January 2009

We study integration over functions on superspaces. These functions are invariant under a transformation which maps the whole superspace onto the part of the superspace which only comprises purely commuting variables. We get a compact expression for the differential operator with respect to the commuting variables which results from Berezin integration over all Grassmann variables. Also, we derive Cauchy-like integral theorems for invariant functions on supervectors and symmetric supermatrices. This extends theorems partly derived by other authors. As a physical application, we calculate the generating function of the one-point correlation function in random matrix theory. Furthermore, we give another derivation of supermatrix Bessel functions for U(k1/k2).
Analysis of temperature behavior of polarized photoluminescence in ordered GaInP layer
Authors: Prutskij T. , Pelosi C. , Brito-Orta R. A.
Published: January 2009

We compare measured and calculated polarization-angle dependences of the intensity of the photoluminescence (PL) emission from a GaInP2 epitaxial layer grown by metalorganic vapor phase epitaxy and analyze the change in the strain within the crystal lattice of the layer. We measured the polarization-angle dependences of the PL emission propagating along the [110] direction at different temperatures. Symmetry considerations were used to calculate the polarization-angle dependences of the relative intensity of the PL emission. At room temperature, this dependence shows that the layers have almost no strain. At temperatures near 70 K, we observed changes in the polarized PL pattern induced by the thermal strain due to the differences between the thermal expansion coefficients of the layer and the substrate. At 10 K, this dependence changed drastically showing the presence of a different recombination process, which is consistent with the S-shaped temperature dependence of the PL emission peak maximum. Comparing the experimental and calculated PL polarization-angle dependences obtained at different temperatures, we estimate the amount of crystal lattice biaxial strain.
Third-order dispersion energy from response functions
Authors: Pernal Katarzyna , Szalewicz Krzysztof
Published: January 2009

In the second order of perturbation theory, the dispersion component of the interaction energy of two atoms or molecules can be expressed as an integral of frequency-dependent response functions of monomers. An analogous formula is derived here for the third-order dispersion energies. The general formula involves a nonstandard response function, but for atoms in asymptotic expansion the expression involves only the standard dynamic hyperpolarizabilities.
Anomalous behavior of acoustic phonon and central peak in Pb[(In1/2Nb1/2)0.65Ti0.35]O3 single crystal
Authors: Sivasubramanian V. , Tsukada S. , Kojima S.
Published: January 2009

The temperature dependences of acoustic phonon mode and the central peak have been investigated in Pb[(In1/2Nb1/2)0.65Ti0.35]O3 single crystal by Brillouin scattering. Longitudinal acoustic phonon begins to show marked softening below the Burns temperature TB∼700 K. The longitudinal acoustic phonon mode exhibits clear anomalies at the cubic-tetragonal phase transition temperature of 540 K and at the tetragonal-rhombohedral one of 460 K. Below 600 K, the relaxation time calculated from the phonon mode agrees well with that of the broad central peak, suggesting a coupling between the local polarization and strain fluctuations of polar nanoregions. This temperature has been identified as another characteristic temperature T∗ besides TB, where the formation of long-lived polar nanoregions accompanied by the local strain fields governs the relaxation dynamics.
Octonic second-order equations of relativistic quantum mechanics
Authors: Mironov Victor L. , Mironov Sergey V.
Published: January 2009

We demonstrate a generalization of relativistic quantum mechanics using eight-component value “octons” that generate an associative noncommutative spatial algebra. It is shown that the octonic second-order equation for the eight-component octonic wave function, obtained from the Einstein relation for energy and momentum, describes particles with spin 1/2. It is established that the octonic wave function of a particle in the state with defined spin projection has a specific spatial structure that takes the form of an octonic oscillator with two spatial polarizations: longitudinal linear and transverse circular.
Midinfrared absorption by InAs/GaSb type-II superlattices
Authors: Li L. L. , Xu W. , Zhang J. , Shi Y. L.
Published: January 2009

We present a systematic theoretical study on optical properties of short-period InAs/GaSb type-II superlattices (SLs) which can serve for midinfrared (MIR) detection. Using the standard Kronig–Penney model we calculate the miniband structure of such SLs. The obtained band-gap energies are in line with those realized experimentally. On the basis of the energy-balance equation derived from the Boltzmann equation we develop a simple approach to calculate the optical absorption coefficient for the corresponding SL systems. Our results agree with recent experimental findings. Moreover, the dependence of MIR absorption in InAs/GaSb type-II SLs on temperature and well width are examined. This study is pertinent to the application of InAs/GaSb type-II SLs as MIR photodetectors working in the ambient condition.
Turbulent boundary layers on a systematically varied rough wall
Authors: Schultz Michael P. , Flack Karen A.
Published: January 2009

Results of an experimental investigation of the flow over a model roughness are presented. The series of roughness consists of close-packed pyramids in which both the height and the slope were systematically varied. The aim of this work was to document the mean flow and subsequently gain insight into the physical roughness scales which contribute to drag. The mean velocity profiles for all nine rough surfaces collapse with smooth-wall results when presented in velocity-defect form, supporting the use of similarity methods. The results for the six steepest surfaces indicate that the roughness function ΔU+ scales almost entirely on the roughness height with little dependence on the slope of the pyramids. However, ΔU+ for the three surfaces with the smallest slope does not scale satisfactorily on the roughness height, indicating that these surfaces might not be thought of as surface “roughness” in a traditional sense but instead surface “waviness.”
A comparative study of single- and multiwalled carbon nanotube sensitivity to ammonia
Authors: Picaud F. , Girardet C. , Rao A. M.
Published: January 2009

We interpret the measured sensitivity difference of single walled carbon nanotubes (SWNTs) and multiwalled carbon nanotubes (MWNTs) used as dielectric sensors of ammonia gas traces in terms of adsorption sites and effective coverages. The dielectric constant of a regular set of SWNTs deposited on a plane is compared to that of a single MWNT having the same size when the same pressure of ammonia molecules is applied on them. The corresponding resonance frequency shifts in the two sensors display an enhanced sensitivity of SWNT over the MWNT in excellent agreement with the experimental measurements.
Grain growth kinetics and electrical properties of lanthanum modified lead zirconate titanate (9/65/35) based ferroelectric ceramics
Authors: Roca R. Alvarez , Botero E. R. , Guerrero F. , Guerra J. D. S. , Garcia D. , Eiras J. A.
Published: January 2009

The influence of the microstructural characteristics on the dielectric and electrical properties has been investigated for Nd3+ doped lanthanum modified lead zirconate titanate ferroelectric ceramics, obtained by the conventional solid-state reaction method, by taking into account different sintering conditions. The grain growth mechanism has been investigated and a cubic-type grain growth law was observed for samples with grain size varying from 1.00 up to 2.35 μm. The porosity and grain size dependences of the phase transition parameters, such as the maximum dielectric permittivity and its corresponding temperature (εm and Tm, respectively) were also investigated. The ac conductivity analyses followed the universal Jonscher law. The behavior of the frequency exponent (s) was analyzed through the correlated barrier hopping model. Both ac and dc conductivity results have been correlated with the observed microstructural features.
Relativistic motion in a constant electromagnetic field
Authors: Chin Siu A.
Published: January 2009

For a relativistic charged particle moving in a constant electromagnetic field, its velocity 4-vector has been well studied. However, despite the fact that both the electromagnetic field and the equations of motion are purely real, the resulting 4-velocity is seemingly due to a complex electromagnetic field. This work shows that this is not due to some complex formalism used (such as Clifford algebra) but is intrinsically due to the fact that the o(3,1) Lie algebra of the Lorentz group is equivalent to two commuting complex su(2) algebras. Expressing the complex su(2) generators in terms of the boost and rotation operators then naturally introduces a complex electromagnetic field. This work solves the equation of motion not as a matrix equation, but as an operator evolution equation in terms of the generators of the Lorentz group. The factorization of the real evolution operator into two commuting complex evolution operators then directly gives the time evolution of the velocity 4-vector without any reference to an intermediate field.
Anomalous nonlinearity parameters of solids at low acoustic drive amplitudes
Authors: Yost William T. , Cantrell John H.
Published: January 2009

Measurements of the nonlinearity parameter β as a function of acoustic drive amplitude are reported for polycrystalline aluminum alloy 2024, IN100 nickel-base superalloy, and monocrystalline Al[110]. The measurements show that the variations in β reported by [Barnard, Appl. Phys. Lett. 74, 2447 (1999)] result from the influence of the Peierls barrier on dislocation motion in the material. The dislocation motion is responsible not only for the hooklike behavior at the low drive amplitudes reported by Barnard but also for an oscillatory dependence of β at larger drive amplitudes not previously reported.
Magnetic anisotropy modulation of magnetite in Fe3O4/BaTiO3(100) epitaxial structures
Authors: Vaz C. A. F. , Hoffman J. , Posadas A.-B. , Ahn C. H.
Published: January 2009

Temperature dependent magnetometry and transport measurements on epitaxial Fe3O4 films grown on BaTiO3(100) single crystals by molecular beam epitaxy show a series of discontinuities, due to changes in the magnetic anisotropy induced by strain from the different crystal phases of BaTiO3. The magnetite film is under tensile strain at room temperature, which is ascribed to the lattice expansion of BaTiO3 at the cubic to tetragonal transition, indicating that the magnetite film is relaxed at the growth temperature. From the magnetization versus temperature curves, the variation in the magnetic anisotropy is determined and compared with the magnetoelastic anisotropies. These results demonstrate the possibility of using the piezoelectric response of BaTiO3 to modulate the magnetic anisotropy of magnetite films.
Strongly localized acoustic surface waves propagating along a V-groove
Authors: Liu Fengming , Peng Shasha , Jia Han , Ke Manzhu , Liu Zhengyou
Published: January 2009

Strongly localized acoustic surface waves propagating along an immersed V-groove are numerically analyzed and experimentally demonstrated. We analyze the dispersion relation and the distribution of displacements of such groove waves using the compact two-dimensional finite-difference time-domain method. It is shown that they are dispersionless and strongly confined in the lateral cross section. The variations in their velocities as a function of the apex angle are also presented. Furthermore, we implement experimental observation by the near-field detection of these predicted waves in the 30° polymethyl methacrylate groove. The experimental measurements of the wave velocities agree very well with the numerical results.
Characteristics of output voltage and current of integrated nanogenerators
Authors: Yang Rusen , Qin Yong , Li Cheng , Dai Liming , Wang Zhong Lin
Published: January 2009

Owing to the anisotropic property and small output signals of the piezoelectric nanogenerators (NGs) and the influence of the measurement system and environment, identification of the true signal generated by the NG is critical. We have developed three criteria: Schottky behavior test, switching-polarity tests, and linear superposition of current and voltage tests. The 11 tests can effectively rule out the system artifacts, whose sign does not change with the switching measurement polarity, and random signals, which might change signs but cannot consistently add up or cancel out under designed connection configurations. This study establishes the standards for designing and scale up of integrated nanogenerators.
Electron energy distribution functions in low-pressure oxygen plasma columns sustained by propagating surface waves
Authors: Stafford L. , Khare R. , Donnelly V. M. , Margot J. , Moisan M.
Published: January 2009

Electron energy distribution functions (EEDFs) were measured in a 50 mTorr oxygen plasma column sustained by propagating surface waves. Trace-rare-gas-optical-emission spectroscopy was used to derive EEDFs by selecting lines to extract “electron temperature” (Te) corresponding to either lower energy electrons that excite high-lying levels through stepwise excitation via metastable states or higher energy electrons that excite emission directly from the ground state. Lower energy Te’s decreased from 8 to 5.5 eV with distance from the wave launcher, while Te≈6 eV for higher energy electrons and Te>20 eV for a high-energy tail. Mechanisms for such EEDFs are discussed.
A “crown of thorns” is an inducible defense that protectsDaphniaagainst an ancient predator
Authors: Petrusek Adam , Tollrian Ralph , Schwenk Klaus , Haas Andreas , Laforsch Christian
Published: January 2009

Genetic data has become an essential part of ecological studies, because the analyses of diversity within and among natural populations may grant access to previously overlooked ecological and evolutionary causalities, especially among cryptic species. Here, we present an example of how phylogenetic analysis of molecular data obtained within a DNA barcoding study, in combination with morphological and ecological data from the field and laboratory experiments, unraveled a striking predator-prey interaction between aquatic organisms. The “crown of thorns,” a conspicuous morphological feature among water fleas of theDaphnia atkinsonispecies complex (Crustacea: Cladocera), is considered to represent a species-specific trait. However, our study, initiated by the analysis of sequence variation in 2 mitochondrial genes, shows that this feature is phenotypically plastic and is induced by chemical cues released byTriops cancriformis, the tadpole shrimp (Notostraca). The trait acts as an effective antipredator defense, and is found in severalDaphnialineages coexisting with notostracans. These facts suggest that the “crown of thorns” evolved in coexistence with this ancient predator group.
Trithorax requires Hsp90 for maintenance of active chromatin at sites of gene expression
Authors: Tariq Muhammad , Nussbaumer Ute , Chen Yujie , Beisel Christian , Paro Renato
Published: January 2009

Molecular chaperone heat-shock protein 90 kDa (Hsp90) is known to facilitate the conformational maturation of a diverse range of proteins involved in different signal transduction pathways during development. Recent studies have implicated Hsp90 in transcriptional regulation and an important role for Hsp90 in epigenetic processes has been proposed. Importantly, genetic and pharmacological perturbation of Hsp90 was shown to reveal heritable phenotypic variation and Hsp90 was found to play an important role in buffering genetic and epigenetic variation whose expression led to altered phenotypes. The underlying molecular mechanism remains elusive, however. Here, we show a direct molecular interaction between Hsp90 and Trithorax (Trx). Trx is a member of the TrxG chromatin proteins controlling, together with the members of the Polycomb group, the developmental fate of cells by modulating epigenetic signals. Hsp90 cooperates with Trx at chromatin for maintaining the active expression state of targets like the Hox genes. Pharmacological inhibition of Hsp90 results in degradation of Trx and a concomitant down-regulation of homeotic gene expression. A similar effect is observed with the human orthologue mixed-lineage leukemia. Connecting an epigenetic network controlling major developmental and cellular pathways with a system sensing external cues may explain the rapid fixation and epigenetic inheritance of phenotypic variation as a result of impaired Hsp90.
Activation of the SK potassium channel-calmodulin complex by nanomolar concentrations of terbium
Authors: Li Weiyan , Aldrich Richard W.
Published: January 2009

Small conductance Ca
2+
-activated K
+
(SK) channels sense intracellular Ca
2+
concentrations via the associated Ca
2+
-binding protein calmodulin. Structural and functional studies have revealed essential properties of the interaction between calmodulin and SK channels. However, it is not fully understood how the binding of Ca
2+
to calmodulin leads to channel opening. Drawing on previous biochemical studies of free calmodulin using lanthanide ions as Ca
2+
substitutes, we have used the lanthanide ion, Tb
3+
, as an alternative ligand to study the activation properties of SK channels. We found that SK channels can be fully activated by nanomolar concentrations of Tb
3+
, indicating an apparent affinity >100-fold higher than Ca
2+
. Competition experiments show that Tb
3+
binds to the same sites as Ca
2+
to activate the channels. Additionally, SK channels activated by Tb
3+
demonstrate a remarkably slow deactivation process. Comparison of our results with previous biochemical studies suggests that in the intact SK channel complex, the N-lobe of calmodulin provides ligand-binding sites for channel gating, and that its ligand-binding properties are comparable to those of the N-lobe in isolated calmodulin.
The Effect of Online Chapter Quizzes on Exam Performance in an Undergraduate Social Psychology Course
Authors: Johnson Bethany C. , Kiviniemi Marc T.
Published: January 2009

Assigned textbook readings are a common requirement in undergraduate courses, but students often do not complete reading assignments or do not do so until immediately before an exam. This may have detrimental effects on learning and course performance. Regularly scheduled quizzes on reading material may increase completion of reading assignments and therefore course performance. This study examined the effectiveness of compulsory, mastery-based, weekly reading quizzes as a means of improving exam and course performance. Completion of reading quizzes was related to both better exam and course performance. The discussion includes recommendations for the use of quizzes in undergraduate courses.
Using Virtual Worlds in Education: Second Life® as an Educational Tool
Authors: Baker Suzanne C. , Wentz Ryan K. , Woods Madison M.
Published: January 2009

The online virtual world Second Life ( www.secondlife.com ) has multiple potential uses in teaching. In Second Life (SL), users create avatars that represent them in the virtual world. Within SL, avatars can interact with each other and with objects and environments. SL offers tremendous creative potential in that users can create content within the virtual world, including buildings, environments, and objects. Psychology instructors can use SL as a space to meet with students, and to create labs, buildings, and objects that can be used to learn psychology content and skills. Students' engagement with course content and sense of community with the class can be enhanced using interactions within SL. Potential drawbacks include learning time required and technological issues involved in using the program. We suggest that instructors using SL formulate clear objectives, start with simple activities, and involve their students in designing and assessing learning activities in the virtual world.
Using an Exemplification Exercise to Teach Psychological Disorders
Authors: Balch William R.
Published: January 2009

At the beginning of the semester, 2 introductory psychology classes took 1 pretest requiring them to match 12 psychological disorders with the correct definitions and another requiring them to match the disorders with appropriate examples. Twelve weeks later, both classes heard lecture material on the disorders. One class also performed an exercise in which students wrote an original example of each disorder. At the end of the period in each class, students took posttests identical to the pretests. The lecture-plus-exercise class performed significantly better than the lecture-only class on the posttests but not on the pretests, reflecting the teaching effectiveness of the exemplification exercise as a supplement to lecture material.
Developing Informed Research Participants in an Introductory Psychology Participant Pool
Authors: Sullivan Michael P. , Lashley Sarah L.
Published: January 2009

This activity offers a way to use the informed consent procedure to help students better understand the responsibilities of research participants. During a class activity, students completed a brief study. The study included presentation of consent forms and questionnaires before a surprise quiz over material from the consent form and a discussion about research ethics. Although students in the class performed poorly on this quiz, evaluations completed by researchers conducting studies within the department indicated that these students demonstrated greater attention to consent forms when completing actual research than did study participants who did not experience this activity. By preparing students to be engaged research participants, this activity helps researchers intentionally link students' participation to their classroom experiences.
What's Going on in Your Professor's Head? Demonstrating the Id, Ego, and Superego
Authors: Segrist Dan J.
Published: January 2009

This article describes an in-class activity designed to demonstrate Freud's structural theory of the psyche, specifically the roles of the id, ego, and superego, as well as the interplay among them. Additionally, the activity visually illustrates Freud's ideas about the levels of consciousness associated with these 3 components. Pre–post quiz performance, evaluation data, and student comments demonstrate that students learned from and enjoyed the activity. Suggestions for modifications of this activity are also discussed.
Psychology is a Science: At Least Some Students Think So
Authors: Holmes Jeffrey D. , Beins Bernard C.
Published: January 2009

The American Psychological Association's (2007) curricular guidelines recommend that students develop both an understanding of how psychologists do research and an appreciation for why scientific thinking is necessary. We surveyed a large sample of psychology majors on specific interests, as well as individual difference variables relevant to scientific thinking. Our results suggest that over time, students' knowledge of scientific thinking increased, whereas their tendency to see psychology as a science did not. Further, students reported greater interest in practitioner activities than scientific ones, and these divergent interests were associated with differential ways of thinking and of viewing the field of psychology. We discuss some implications for conceptualizing undergraduate instruction given that some student characteristics are more malleable than others.
Putting words in their mouths: The alignment of identities with system goals through the use of Individual Learning Plans
Authors: Hamilton Mary
Published: January 2009

This article analyses the role of Individual Learning Plans (ILPs) in teachers' work in theSkills for Lifesector. It shows how ILPs, originally a means of formative assessment, have become part of a system of performance indicators and function as a key mediating mechanism between local interactions and system goals. The article draws on theoretical perspectives from the new literacy studies and the sociology of science to reveal the pivotal role of texts in projects of social ordering. The methodology is a version of institutional ethnography, whereby an artefact (the ILP) is tracked as it circulates across the different sites of its production and use. Documentary and interview evidence are used. The article concludes that, in its current form, the ILP shapes teaching and learning relationships and aligns both tutor and student identities. Permissive guidance, combined with a core curriculum, the demands of audit and inspection, positions tutors uncomfortably as active mediators between student experience and the policy discourse.
Children with speech, language and communication needs: their perceptions of their quality of life
Authors: Markham Chris , van Laar Darren , Gibbard Deborah , Dean Taraneh
Published: January 2009

Background: This study is part of a programme of research aiming to develop a quantitative measure of quality of life for children with communication needs. It builds on the preliminary findings of Markham and Dean (2006), which described some of the perception's parents and carers of children with speech language and communication needs had regarding children's experience of quality of life. However, this earlier study did not observe and evaluate the perceptions of children themselves and consequently left a vital gap in the evidence. The study reported here seeks to address this by describing the quality of life experiences reported by children and young people themselves.

Aims: The study aimed to provide a qualitative, child‐centred, description of the quality of life experiences of children and young people with speech language and communication needs.

Methods & Procedures: The study used a qualitative methodology to provide a credible and thick description of the quality of life experiences of children and young people with speech language and communication needs. Children and young people participating in the study were selected to represent a range of speech and language pathologies, according to their capacity to comprehend and participate within the data‐collection activities. A modified focus group technique was used as a method of data collection and data were analysed according to the principles of Grounded Theory and Framework analysis.

Outcomes & Results: Seven focus group interviews were conducted with a range of children and young people in full‐time education and in receipt of speech and language therapy. The data showed a number of key themes regarding children's quality of life experiences. These themes ranged from the participant's perceptions of what improves their daily lives to the difficulties they experience and consequently the negative impacts perceived on their quality of life.

Conclusions & Implications: This study illuminates the quality of life experiences of children with speech language and communication needs. The findings are of direct benefit to clinicians, researchers, and policy‐makers alike as they broaden the understanding of children's speech and language difficulties. Despite the potential bias inherent in qualitative research with children, the findings provide support for the development of a quality of life scale for children with speech language and communication needs. Such an outcome measure would enable clinicians and researchers to quantify children's quality of life, thereby broadening the range of clinical outcomes available.
Direct versus indirect and individual versus group modes of language therapy for children with primary language impairment: principal outcomes from a randomized controlled trial and economic evaluation
Authors: Boyle James M. , McCartney Elspeth , O'Hare Anne , Forbes John
Published: January 2009

Background: Many school‐age children with language impairments are enrolled in mainstream schools and receive indirect language therapy, but there have been, to the authors' knowledge, no previous controlled studies comparing the outcomes and costs of direct and indirect intervention delivered by qualified therapists and therapy assistants, and each delivery mode offered to children individually or in groups.

Aims: To investigate the relative effectiveness of indirect and direct intervention therapy modes delivered individually or in groups for children with primary language impairment.

Methods & Procedures: A multi‐centre randomized controlled trial investigated 161 children with primary language impairment aged 6–11 years randomized to a usual‐therapy control group or to direct individual, indirect individual, direct group or indirect group therapy modes. Intervention was delivered three times a week for 30–40‐min sessions in mainstream schools over 15 weeks. Language performance was assessed at baseline, post‐therapy and at 12 months. Cost analysis was based on salary and travel costs for intervention modes and usual therapy.

Outcomes & Results: Compared with controls, children receiving project therapy made short‐term improvements in expressive (p = 0.031), but not receptive, language immediately following intervention. Children with specific expressive language delay were more likely to show improvement than those with mixed receptive–expressive difficulties. The four project therapy modes did not differ on primary language outcomes (all p‐values>0.392) and there were no further improvements evident at follow‐up. Indirect group therapy was the least costly mode, with direct individual therapy the most costly.

Conclusions & Implications: Intervention in this age group can be effective for expressive language and can be delivered equally effectively though speech and language therapy assistants and to children in groups.
Qualitative study of the therapeutic relationship in speech and language therapy: perspectives of adults with acquired communication and swallowing disorders
Authors: Fourie Robert J.
Published: January 2009

Background: Considerations of the negotiated therapeutic relationship in speech and language therapy are somewhat scarce, with specific therapeutic factors generally framed from psycholinguistic, behavioural, or neurological perspectives.

Aims: To explore the therapeutic relationship in speech and language therapy, focusing on the personal meanings and experiences of adult clients with acquired communication and swallowing disorders.

Methods & Procedures: The study was qualitative, using methods from Grounded theory to analyse eleven interviews with adults who had acquired disorders of communication or swallowing, as they described their perceptions of speech and language therapy and therapists. Five males and six females with a mean age of 62 years, ranging from 25 to 87 years, with varied communication disorders, were interviewed.

Outcomes & Results: A preliminary theoretical framework explains how speech and language therapists supported alienated, demoralized or confused clients with therapeutic qualities, such as Being Understanding, Being Gracious, Being Erudite and Being Inspiring; and with therapeutic actions, such as Being Confident, Being Soothing, Being Practical and Being Empowering. These categories provided a basis for the researcher to construct a substantive theory of restorative poise which characterized the attitudinal and behavioural characteristics of an ideal speech and language therapist from the perspective of the client.

Conclusions & Implications: Participants were aware of the components of a therapeutic relationship and valued these as essential to their own personal understanding of positive outcomes in speech and language therapy. Therefore, specific types of attitudes and actions that constitute the speech and language therapist's contributions to the therapeutic relationship seemed to provide catalytic conditions for successful working together in therapy; and consequently, may have a bearing on effective practice and treatment efficacy.