bluuebunny/crossref_metadata_2025 huggingface dataset:
Role, mission, and change in our introductory collegiate physics courses
Authors: Bartlett Albert A.
Published: March 2005

Efforts are being made to restructure the introductory college course in physics. The effort seems to be to shift the emphasis away from 100-, 200-, and 300-year-old physics to more modern topics. This article argues that the conventional course in physics should be preserved and strengthened for its utility and widespread applicability.
A finite-differences technique for propagating uncertainty in calculations
Authors: Piccard Richard D.
Published: March 2005

The propagation of errors in calculations is conventionally treated analytically. This Journal recently published a new treatment based on a numerical simulation method using pseudorandom numbers. This article presents a deterministic method that requires less extra computation than the simulation method, uses the directly estimated true value and uncertainty for each measured quantity, and naturally generates estimates of the contributions to the uncertainty from each source. By avoiding the relatively subtle concept of the covariances of the measured quantities, the method presented here is more readily appreciated by intermediate level students (physics majors or nonscientists), although it cannot be used to determine whether the random errors of measurement are correlated.
Augmenting traditional undergraduate advanced laboratory experiments by automation using IEEE-488 and RS-232 interfaces
Authors: Nornes S. , Tu Y. Z.
Published: March 2005

Meaningful and effective use of the computer in undergraduate physics teaching has been unexpectedly and somewhat paradoxically slow. Some upper division laboratory experiments are described in which the computer is used in a way that preserves the traditional value and importance of classic experiments and minimizes the intrusion of the computer. Experiments and the equipment are chosen to minimize programming and focus attention on the physics of the experiment. Both the IEEE-488 and RS-232 standards have been used to interface several experiments including one on the mass spectrometer, gamma-ray spectroscopy, and the Franck–Hertz experiment. The computer is interfaced only with experiments in which its use enhances the experiment by providing an immediate response to a change of input variables, such as a real-time plot of output variables, or where its use will facilitate collecting and analyzing large amounts of data that would otherwise be prohibitively time consuming.
Hermann von Helmholtz and his students
Authors: Mulligan Joseph F.
Published: March 2005

During the years 1871–1888, when Hermann von Helmholtz was professor of physics at the University of Berlin, physicists from all over the world flocked to Berlin to study and do research with him. Among these were the German physicists Max Planck, Heinrich Kayser, Eugen Goldstein, Wilhelm Wien, and Heinrich Hertz, and Americans Henry Rowland, A. A. Michelson, and Michael Pupin. Examples of Helmholtz’s scientific and personal interactions with these students and research associates show why he is justly considered the outstanding physics mentor of the 19th century. Both his ideas and his students played a major role in the development of physics in the late 19th and early 20th centuries.
Conserved vectors and orbit equations for autonomous systems governed by the equation of motion r̈+f ṙ+g
r=0
Authors: Gorringe V. M. , Leach P. G. L.
Published: March 2005

The existence of conserved vectors that are analogous to the conserved angular momentum and Laplace–Runge–Lenz vectors of the classical Kepler problem makes it possible to determine the orbit equations for a wide variety of autonomous systems governed by the equation of motion of the form r̈+f ṙ+gr=0.
An experiment on the physical reality of edge-diffracted waves
Authors: Ganci Salvatore
Published: March 2005

An experiment that deals with the physical reality of the edge-diffracted wave in the boundary wave theory of diffraction is described in this article. The basic philosophy is simple and the experimental evidence is strong.
Actually, Eötvös did publish his results in 1910, it’s just that no one knows about it...
Authors: Nieto Michael Martin , Hughes Richard J. , Goldman T.
Published: March 2005

Actually Eötvös did publish his results in 1910, but no one knows about it because it was added at the end of a geophysics paper published in the proceedings of an international conference. After a short review of Eötvös’ life, this article reports how the first publication of the results of his famous experiment was ‘‘lost.’’ This and other historical curiosities about his work are related to the current interest in his results and modern theories of quantum gravity. The appendices explain how the Eötvös balance works and also describe the controversy over the modern reanalysis of Eötvös’ results.
Multiple scattering approach to one-dimensional potential problems
Authors: Anderson Arlen
Published: March 2005

By calculating the reflection and transmission coefficients for a square potential barrier in terms of a series of scatterings at step potential discontinuities, a multiple scattering approach to potential problems is presented. This approach is applied to WKB potential problems by interpreting the WKB connection formulas in terms of reflection and transmission coefficients at each turning point. An algorithm for the systematic construction of the energy Green’s function is given. The significance of complex coordinate turning points is demonstrated. The equivalence of this approach and that of the Gaussian approximation of the path integral is mentioned briefly.
How Rutherford missed discovering quantum mechanical identity
Authors: Temmer G. M.
Published: March 2005

An interesting quirk in the energy dependence of alpha-particle scattering from helium caused Lord Rutherford to miss a major discovery—namely, the consequences of quantum mechanical identity—before their prediction by Mott a short time later.
Electrodynamics of moving dipoles: The case of the missing torque
Authors: Namias Victor
Published: March 2005

In a recent article, Bedford and Krumm [‘‘On the Origin of Magnetic Dynamics,’’ Am. J. Phys. 54, 1036 (1986)], examine in detail the interaction between a moving line of charges and a magnetic dipole consisting of a conducting ring of current from the point of view of different frames of reference. One particular orientation of the magnetic dipole leads to an apparently paradoxical situation of a torque acting in one inertial frame but not in another. These authors explain the situation by considering the rate of change of mass of the charge carriers and a wall force that prevents them from accelerating in the direction of their motion. They also hint at an intriguing analogy with some kind of inertial or fictitious force such as occurs in noninertial frames. First, the general expression is derived for the torque on a moving magnetic dipole in any orientation and the term representing the missing torque is explicitly revealed. Then the physical origin of this torque is investigated in the particular case considered by Bedford and Krumm, where the magnetic dipole consists of a small current-carrying conducting loop. It appears that, in this case, the elusive torque arises from the interaction between the current carriers in the magnetic dipole loop and the magnetic field due to the surface current generated by the motion of the induced charges on the surface of the conducting loop.
Applications of Bohr’s correspondence principle
Authors: Crawford Frank S.
Published: March 2005

The Bohr correspondence-principle (cp) formula dE/dn=ℏω is presented (ω is the classical angular frequency) and its predicted energy levels En are compared to those given by the stationary state solutions of the Schrödinger equation, first for several examples in one dimension (1D), including the ‘‘quantum bouncer,’’ and then for several examples in three dimensions (3D), including the hydrogen atom and the isotropic harmonic oscillator. For the 3-D cases, the cp predictions based on classical circular orbits are compared with the ‘‘circlelike’’ Schrödinger solutions (those with the lowest energy eigenvalue for a given l) and the cp predictions based on classical ‘‘needle’’ orbits (having zero angular momentum) with the Schrödinger l=0 solutions. For the H atom and the isotropic oscillator, the cp prediction does not depend on the classical orbit chosen because of a ‘‘degeneracy’’: the fact that for these systems ω is independent of the orbit. As a more stringent test of the cp, analogous nondegenerate systems V=−k/r3/2 in place of the H-atom potential V=−e2/r and V=kr4 in place of the oscillator potential V=(1/2)mω2r2 are therefore considered. An interesting anomaly that occurs for the harmonic oscillator and its nondegenerate analog V=kr4 is encountered (but not for the H atom nor its nondegenerate analog V=−k/r3/2), wherein half of the states predicted by application of the cp to the needle orbits are ‘‘spurious’’ in that there are no corresponding Schrödinger l=0 states. The assumption that generated the spurious cp states is uncovered—a plausible, but erroneous factor of 2 in calculating the classical frequency—and thus the spurious states are eliminated.
A double pendulum swing experiment: In search of a better bat
Authors: Cross Rod
Published: March 2005

Experimental results on the large-amplitude motion of a double pendulum are presented, with emphasis on the first half cycle. The initial part of the swing is reproducible and is of interest in modeling various human movement activities such as running, throwing, kicking, and the swing of a bat or racquet. Beyond this time, the motion is chaotic. The forces and torques acting on each pendulum segment are analyzed to explain its motion. The results show how a “perfect” bat could be designed where all the kinetic energy from the player’s arms is transferred to the ball and none is retained in the arms or the bat after the impact.
A scaling approach to ideal quantum gases
Authors: Nattermann Thomas
Published: March 2005

The thermodynamic properties of ideal quantum gases are derived solely from dimensional arguments, the Pauli principle, and thermodynamic relations, without resorting to statistical mechanics.
Material property measurement using the quasi-Scholte mode—A waveguide sensor
Authors: Cegla F. B. , Cawley P. , Lowe M. J. S.
Published: March 2005

In the food industry and other industries, rheological measurements and determination of particle sizes in suspensions and emulsions is of great importance for process and quality control. Current test cell based ultrasonic methods exist but are often inconvenient. An attractive alternative could be to insert a simple measurement “dipstick” into the fluid; this paper presents an initial study of the feasibility of using measurements of the velocity and attenuation of the quasi-Scholte mode on a plate to obtain the longitudinal velocity and attenuation of an embedding medium. The attenuation of the quasi-Scholte mode is caused by two mechanisms: shear leakage and attenuation due to the bulk longitudinal attenuation of the embedding material. In a calibration test the bulk longitudinal velocity and viscosity of glycerol were determined experimentally. Measurements agreed well with results from conventional methods and literature data. Quantitative results and an independent validation for honey, a very viscous fluid, are also presented. For Newtonian liquids like glycerol and honey, the shear leakage and longitudinal bulk attenuation are both related to viscosity. To demonstrate the sensitivity to nonviscous attenuation mechanisms, qualitative measurement results on fluids that mainly exhibit attenuation due to scattering are presented.
An efficient method for evaluating diffuse field joint acceptance functions for cylindrical and truncated conical geometries
Authors: Coyette Jean-Pierre , Lielens Grégory , Robbé Mickaël , Neple Pascale
Published: March 2005

The evaluation of the response of elastic structures subjected to distributed random excitations is usually performed in the modal space. Random excitations (like acoustic diffuse fields) are usually modeled as weakly stationary random processes and are assumed to be homogeneous. Their characterization basically relies on the power spectral density (PSD) function of the pressure at a particular reference position and a suitable spatial correlation function. In the modal space, the distributed random excitation is characterized by a modal PSD matrix made from the joint acceptance functions related to the mode pairs. The joint acceptance function is a double surface integral involving the product of the considered mode shapes and the spatial correlation function. The paper shows how to evaluate efficiently this quadruple integral for cylindrical and truncated conical structures excited by an acoustic diffuse field. Basically, the procedure relies on the derivation of alternative expressions for the spatial correlation function. The related expressions prove to be more convenient for these geometries and are leading to a reduction of the double surface integral to a combination of simple integrals. A very substantial breakdown of the computational cost can be achieved using the resulting expressions.
Characteristics of the audio sound generated by ultrasound imaging systems
Authors: Fatemi Mostafa , Alizad Azra , Greenleaf James F.
Published: March 2005

Medical ultrasound scanners use high-energy pulses to probe the human body. The radiation force resulting from the impact of such pulses on an object can vibrate the object, producing a localized high-intensity sound in the audible range. Here, a theoretical model for the audio sound generated by ultrasound scanners is presented. This model describes the temporal and spectral characteristics of the sound. It has been shown that the sound has rich frequency components at the pulse repetition frequency and its harmonics. Experiments have been conducted in a water tank to measure the sound generated by a clinical ultrasound scanner in various operational modes. Results are in general agreement with the theory. It is shown that a typical ultrasound scanner with a typical spatial-peak pulse-average intensity value at 2 MHz may generate a localized sound-pressure level close to 100 dB relative to 20 μPa in the audible (<20 kHz) range under laboratory conditions. These findings suggest that fetuses may become exposed to a high-intensity audio sound during maternal ultrasound examinations. Therefore, contrary to common beliefs, ultrasound may not be considered a passive tool in fetal imaging.
Spectral subtraction-based speech enhancement for cochlear implant patients in background noise
Authors: Yang Li-Ping , Fu Qian-Jie
Published: March 2005

A single-channel speech enhancement algorithm utilizing speech pause detection and nonlinear spectral subtraction is proposed for cochlear implant patients in the present study. The spectral subtraction algorithm estimates the short-time spectral magnitude of speech by subtracting the estimated noise spectral magnitude from the noisy speech spectral magnitude. The artifacts produced by spectral subtraction (such as “musical noise”) were significantly reduced by combining variance-reduced gain function and spectral flooring. Sentence recognition by seven cochlear implant subjects was tested under different noisy listening conditions (speech-shaped noise and 6-talker speech babble at +9, +6, +3, and 0 dB SNR) with and without the speech enhancement algorithm. For speech-shaped noise, performance for all subjects at all SNRs was significantly improved by the speech enhancement algorithm; for speech babble, performance was only modestly improved. The results suggest that the proposed speech enhancement algorithm may be beneficial for implant users in noisy listening.
Radiative transfer theory for high-frequency power flows in fluid-saturated, poro-visco-elastic media
Authors: Savin Eric
Published: March 2005

Some recent mathematical results are used to study the propagation features of the high-frequency vibrational energy density in three-dimensional fluid-saturated, isotropic poro-visco-elastic media. The theory of high-frequency asymptotics of the solutions of hyperbolic partial differential equations shows that their energy satisfies Liouville-type transport or radiative transfer equations for randomly heterogeneous materials. For long propagation times these equations can be approached by diffusion equations. The corresponding diffusion parameters—mean-free paths and diffusion constants—associated with Biot’s linear model for such media, are derived. The analysis accounts for the thermal and viscous memory effects of the fluid phase, and the viscous memory effect of the solid phase through time convolution operators. In this respect it also extends the existing mathematical results.
Encoding of vowel-like sounds in the auditory nerve: Model predictions of discrimination performance
Authors: Tan Qing , Carney Laurel H.
Published: March 2005

The sensitivity of listeners to changes in the center frequency of vowel-like harmonic complexes as a function of the center frequency of the complex cannot be explained by changes in the level of the stimulus [Lyzenga and Horst, J. Acoust. Soc. Am. 98, 1943–1955 (1995)]. Rather, a complex pattern of sensitivity is seen; for a spectrum with a triangular envelope, the greatest sensitivity occurs when the center frequency falls between harmonics, whereas for a spectrum with a trapezoidal envelope, greatest sensitivity occurs when the center frequency is aligned with a harmonic. In this study, the thresholds of a population model of auditory-nerve (AN) fibers were quantitatively compared to these trends in psychophysical thresholds. Single-fiber and population model responses were evaluated in terms of both average discharge rate and the combination of rate and timing information. Results indicate that phase-locked responses of AN fibers encode phase transitions associated with minima in these amplitude-modulated stimuli. The temporal response properties of a single AN fiber, tuned to a frequency slightly above the center frequency of the harmonic complex, were able to explain the trends in thresholds for both triangular- and trapezoidal-shaped spectra.
Retrofocusing techniques for high rate acoustic communications
Authors: Stojanovic Milica
Published: March 2005

High rate underwater communications have traditionally relied on equalization methods to overcome the intersymbol interference (ISI) caused by multipath propagation. An alternative technique has emerged in the form of time-reversal, which comes at virtually no cost in computational complexity, but sacrifices the data rate and relies on the use of large arrays to reduce ISI. In this paper, spatiotemporal processing for optimal multipath suppression is addressed analytically. A communication link between a single element and an array is considered in several scenarios: uplink and downlink transmission, with and without channel state information and varying implementation complexity. Transmit/receive techniques are designed which simultaneously maximize the data detection signal-to-noise ratio and minimize the residual ISI, while maintaining maximal data rate in a given bandwidth and satisfying a constraint on transmitted energy. The performance of so-obtained focusing techniques is compared to the standard ones on a shallow water channel operating in a 5 kHz bandwidth around a 15 kHz center frequency. Results demonstrate benefits of focusing techniques whose performance is not conditioned on the array size. Optimal configurations are intended as a basis for adaptive system implementation in which channel estimates will replace the actual values.
Insertional Polymorphisms of Endogenous Feline Leukemia Viruses
Authors: Roca Alfred L. , Nash William G. , Menninger Joan C. , Murphy William J. , O'Brien Stephen J.
Published: March 2005

The number, chromosomal distribution, and insertional polymorphisms of endogenous feline leukemia viruses (enFeLVs) were determined in four domestic cats (Burmese, Egyptian Mau, Persian, and nonbreed) using fluorescent in situ hybridization and radiation hybrid mapping. Twenty-nine distinct enFeLV loci were detected across 12 of the 18 autosomes. Each cat carried enFeLV at only 9 to 16 of the loci, and many loci were heterozygous for presence of the provirus. Thus, an average of 19 autosomal copies of enFeLV were present per cat diploid genome. Only five of the autosomal enFeLV sites were present in all four cats, and at only one autosomal locus, B4q15, was enFeLV present in both homologues of all four cats. A single enFeLV occurred in the X chromosome of the Burmese cat, while three to five enFeLV proviruses occurred in each Y chromosome. The X chromosome and nine autosomal enFeLV loci were telomeric, suggesting that ectopic recombination between nonhomologous subtelomeres may contribute to enFeLV distribution. Since endogenous FeLVs may affect the infectiousness or pathogenicity of exogenous FeLVs, genomic variation in enFeLVs represents a candidate for genetic influences on FeLV leukemogenesis in cats.
Human Papillomavirus Type 16 E1
∧
E4-Induced G
2
Arrest Is Associated with Cytoplasmic Retention of Active Cdk1/Cyclin B1 Complexes
Authors: Davy Clare E. , Jackson Deborah J. , Raj Kenneth , Peh Woei Ling , Southern Shirley A. , Das Papia , Sorathia Rina , Laskey Peter , Middleton Kate , Nakahara Tomomi , Wang Qian , Masterson Phillip J. , Lambert Paul F. , Cuthill Scott , Millar Jonathan B. A. , Doorbar John
Published: March 2005

Human papillomavirus type 16 (HPV16) can cause cervical cancer. Expression of the viral E1
∧
E4 protein is lost during malignant progression, but in premalignant lesions, E1
∧
E4 is abundant in cells supporting viral DNA amplification. Expression of 16E1
∧
E4 in cell culture causes G
2
cell cycle arrest. Here we show that unlike many other G
2
arrest mechanisms, 16E1
∧
E4 does not inhibit the kinase activity of the Cdk1/cyclin B1 complex. Instead, 16E1
∧
E4 uses a novel mechanism in which it sequesters Cdk1/cyclin B1 onto the cytokeratin network. This prevents the accumulation of active Cdk1/cyclin B1 complexes in the nucleus and hence prevents mitosis. A mutant 16E1
∧
E4 (T22A, T23A) which does not bind cyclin B1 or alter its intracellular location fails to induce G
2
arrest. The significance of these results is highlighted by the observation that in lesions induced by HPV16, there is evidence for Cdk1/cyclin B1 activity on the keratins of 16E1
∧
E4-expressing cells. We hypothesize that E1
∧
E4-induced G
2
arrest may play a role in creating an environment optimal for viral DNA replication and that loss of E1
∧
E4 expression may contribute to malignant progression.
Human Immunodeficiency Virus-Specific Responses in Adult Ugandans: Patterns of Cross-Clade Recognition
Authors: Barugahare Banson , Baker Chris , K'Aluoch Okumu , Donovan Richard , Elrefaei Mohamed , Eggena Mark , Jones Norman , Mutalya Steven , Kityo Cissy , Mugyenyi Peter , Cao Huyen
Published: March 2005

Human immunodeficiency virus (HIV) or AIDS is currently the leading cause of death in Uganda, with at least three HIV clades (subtypes) accounting for most new infections. Whether an effective vaccine formulated on viruses from a single clade will be able to protect against infection from other local clades remains unresolved. We examined the T-cell immune responses from a cohort of HIV-seropositive individuals in Uganda with predominantly clade A and D infections. Surprisingly, we observed similar frequencies of cross-clade T-cell responses to the
gag
,
env
, and
nef
regions. Our data suggest that the level of viral sequence variability between distinct HIV strains does not predict the degree of cross-clade responses. High sequence homologies were also observed between consensus peptides and sequences from viral isolates, supporting the use of consensus amino acid sequences to identify immunogenic regions in studies of large populations.
Mechanisms of Nonrandom Human Immunodeficiency Virus Type 1 Infection and Double Infection: Preference in Virus Entry Is Important but Is Not the Sole Factor
Authors: Chen Jianbo , Dang Que , Unutmaz Derya , Pathak Vinay K. , Maldarelli Frank , Powell Douglas , Hu Wei-Shau
Published: March 2005

We previously demonstrated that human immunodeficiency virus type 1 (HIV-1) infection is nonrandom and that double infection occurs more frequently than predicted from random events. To probe the possible mechanisms for nonrandom infection, we examined the role of HIV-1 entry pathways by using viruses pseudotyped with either CCR5-tropic HIV-1 Env or vesicular stomatitis virus G protein (VSV G). These two proteins use different receptors and entry pathways. We found that regardless of the protein used, double infection occurred more frequently than random events, indicating nonrandom HIV-1 infection in both entry pathways. However, the frequency of double infection differed significantly, depending on the envelope protein. In primary CD4
+
T cells, double infection occurred most frequently when both viruses had CCR5-tropic HIV-1 Env and least frequently when the two viruses had different envelopes. These results indicated that the preference in virus entry was a significant but not the only factor contributing to nonrandom double infection. Furthermore, we demonstrated that the CD4 expression level in primary T cells affects their susceptibility to CCR5-tropic HIV-1 infection but not VSV G-pseudotyped HIV-1 infection. We have also examined infection with two viruses pseudotyped with CCR5- or CXCR4-tropic HIV-1 Env and have found that double infection occurred more frequently than random events. These results indicate that coreceptor usage is not a barrier to recombination between the two virus populations. In our previous study, we also demonstrated nonrandom double infection via dendritic cell (DC)-mediated HIV-1 transmission. To test our hypothesis that multiple HIV-1 virions are transmitted during DC-T-cell contact, we used two populations of DCs, each capturing one vector virus, and added both DC populations to T cells. We observed a decreased frequency of double infection compared with experiments in which DCs captured both viruses simultaneously. Therefore, these results support our hypothesis that multiple virions are transmitted from DCs to T cells during cell-mediated HIV-1 transmission.
LOW ENERGY DOUBLE-PION PHOTOPRODUCTION IN NUCLEI
Authors: ALVAREZ-RUSO L. , MÜHLICH P. , BUSS O. , MOSEL U.
Published: March 2005

We have investigated π0π0 and π±π0 photoproduction off complex nuclei. Simulations have been performed by means of a semi-classical BUU transport model including a full coupled-channel treatment of the final state interactions. We show that the target mass dependence of the π0π0 invariant mass spectrum as measured by the TAPS collaboration can be explained without introducing medium effects beyond absorption and quasi-elastic scattering of the final state particles. On the other hand, we find considerable discrepancies with the data in the π±π0 channel, which are not understood.
VECTOR AND AXIAL-VECTOR CORRELATORS IN AN INSTANTON-LIKE QUARK MODEL
Authors: DOROKHOV ALEXANDER E.
Published: March 2005

The behavior of the vector Adler function at spacelike momenta is studied in the framework of a covariant chiral quark model with instanton-like quark-quark interaction. This function describes the transition between the high energy asymptotically free region of almost massless current quarks to the low energy hadronized regime with massive constituent quarks. The model reproduces the Adler function and V-A correlator extracted from the ALEPH and OPAL data on hadronic τ lepton decays, transformed into the Euclidean domain via dispersion relations. The leading order contribution from hadronic part of the photon vacuum polarization to the anomalous magnetic moment of the muon, [Formula: see text], is estimated.
NEW RESULTS ON THE pd→3Heη PRODUCTION NEAR THRESHOLD
Authors: ADAM H.-H. , KHOUKAZ A. , LANG N. , LISTER T. , SANTO R. , STELTENKAMP S. , CZYŻYKIEWICZ R. , JANUSZ M. , JARCZYK L. , KAMYS B. , MOSKAL P. , PISKOR-IGNATOWICZ C. , PRZERWA J. , SMYRSKI J. , GRZONKA D. , KILIAN K. , OELERT W. , SEFZICK T. , WINTER P. , WOLKE M. , WÜSTNER P. , BUDZANOWSKI A. , ROŻEK T. , SIEMASZKO M. , ZIPPER W.
Published: March 2005

Measurements on the η meson production in proton-deuteron collisions have been performed using the COSY-11 facility at COSY (Jülich). Here we present preliminary results on total and differential cross sections for the pd→3 He η reaction at five excess energies between Q=5.1 and Q=40.6 MeV. The obtained angular distributions for the emitted η mesons in the center of mass system expose a transition from an almost isotropic emission to a highly anisotropic distribution. The extracted total cross sections support a strong η-3 He final state interaction and will be compared with model predictions.
Macrostructural Analyses of Race, Ethnicity, and Violent Crime: Recent Lessons and New Directions for Research
Authors: Peterson Ruth D. , Krivo Lauren J.
Published: March 2005

In 1995, Sampson & Wilson assessed the state of knowledge on race and violence and set forth an approach for future research. We review macrostructural analyses of race, ethnicity, and violent crime since 1995 to evaluate progress in explaining inequality in criminal violence across racial and ethnic groups. Among the important advances are studies that attempt to gain insights from explicit comparisons of racially distinct but structurally similar communities, expansion of work beyond the black-white divide, and incorporation of macrostructural factors into multilevel models of racial/ethnic differences in violence. Yet, progress is limited in all these directions, and additional questions remain. Thus, we offer a perspective and suggestions for future research that will expand knowledge on this important topic.
Events at the Host-Microbial Interface of the Gastrointestinal Tract I. Adaptation to a microbial world: role of epithelial bactericidal/permeability-increasing protein
Authors: Canny Geraldine , Colgan Sean P.
Published: March 2005

Epithelial cells of many mucosal organs have adapted to coexist with microbes and microbial products. In general, most studies suggest that epithelial cells benefit from interactions with commensal microorganisms present at the lumenal surface. However, potentially injurious molecules found in this microenvironment also have the capacity to elicit local inflammatory responses and even systemic disease. In this environment, the epithelium has evolved effective mechanisms to cope with microbial products and to provide appropriate responses to potential pathogens. Although our understanding of these mechanisms is clearly in its infancy, a number of recent findings provide insight into phenotypic characteristics that allow for this discrimination. Here, we briefly review some of these mechanisms, with particular attention to epithelial expression of the anti-infective molecule bactericidal/permeability-increasing protein.
Ischemic preconditioning, insulin, and morphine all cause hexokinase redistribution
Authors: Zuurbier Coert J. , Eerbeek Otto , Meijer Alfred J.
Published: March 2005

Association of hexokinase (HK) with mitochondria preserves mitochondrial integrity and is an important mechanism by which cancer cells are protected against hypoxic conditions. Maintenance of mitochondrial integrity also figures prominently as a major characteristic of many cardioprotective manipulations. In this study, we provide evidence that cardioprotective interventions may promote HK redistribution from the cytosol to the mitochondria in the heart. Isolated Langendorff-perfused rat hearts ( n = 6/group) were subjected to normoxic perfusion (control, Con), three 5-min ischemia-reperfusion periods (ischemic preconditioning, IPC), 1 U/l insulin (Ins), or 1 μM morphine (Mor). Hearts were immediately homogenized and centrifuged to obtain whole cell, cytosolic, and mitochondrial fractions. HK, lactate dehydrogenase (LDH), and citrate synthase (CS) enzyme activities were determined. No change in LDH or CS present in the cytosol fraction relative to whole cell activity was observed with any of the cardioprotective interventions. By contrast, HK present in the cytosol fraction relative to whole cell activity decreased significantly ( P < 0.05) with all cardioprotective interventions, from 0.58 ± 0.03 (Con) to 0.46 ± 0.04 (IPC), 0.41 ± 0.01 (Ins), and 0.45 ± 0.02 (Mor). In addition, HK relative to CS activity in the mitochondrial fraction increased significantly with cardioprotection, from 0.15 ± 0.001 (Con) to 0.21 ± 0.002 (IPC), 0.18 ± 0.003 (Ins), and 0.21 ± 0.005 (Mor). Our novel data suggest that well-known cardioprotective interventions share a common end-effector mechanism of cytosolic HK translocation. Association of HK with mitochondria may promote inhibition of the mitochondrial permeability transition pore and thereby reduce cell death and apoptosis.
Reactive oxygen species from smooth muscle mitochondria initiate cold-induced constriction of cutaneous arteries
Authors: Bailey S. R. , Mitra S. , Flavahan S. , Flavahan N. A.
Published: March 2005

Cold constricts cutaneous blood vessels by selectively increasing the activity of smooth muscle α2-adrenoceptors (α2-ARs). In mouse tail arteries, α2-AR constriction is mediated by α2A-ARs at 37°C, whereas the cold-induced augmentation in α2-AR activity is mediated entirely by α2C-ARs. Cold causes translocation of α2C-ARs from the trans-Golgi to the plasma membrane, mediated by cold-induced activation of RhoA and Rho kinase. The present experiments analyzed the mechanisms underlying these responses. Mouse tail arteries were studied in a pressure myograph. Cooling the arteries (28°C) caused a rapid increase in reactive oxygen species (ROS) in smooth muscle cells, determined by confocal microscopy of arteries loaded with the ROS-sensitive probes, dichlorodihydrofluorescein or reduced Mitotracker Red. The inhibitor of mitochondrial complex I rotenone (10 μmol/l), the antioxidant N-acetylcysteine (NAC; 20 mmol/l), or the cell-permeable mimic of superoxide dismutase MnTMPyP (50 μmol/l) did not affect vasoconstriction to α2-AR stimulation (UK-14304) at 37°C but dramatically inhibited the response at 28°C. Indeed, these ROS inhibitors abolished the cold-induced increase in α2-AR constrictor activity. NAC (20 mmol/l) or MnTMPyP (50 μmol/l) also abolished the cold-induced activation of RhoA in human cultured vascular smooth muscle cells and the cold-induced mobilization of α2C-ARs to the cell surface in human embryonic kidney 293 cells transfected with the receptor. The combined results suggest that cold-induced constriction is mediated by redox signaling in smooth muscle cells, initiated by mitochondrial generation of ROS, which stimulate RhoA/Rho kinase signaling and the subsequent mobilization of α2C-ARs to the cell surface. Altered activity of ROS may contribute to cold-induced vasospasm occurring in Raynaud's phenomenon.
Lattice parameter measurement using Le Bail versus structural (Rietveld) refinement: A caution for complex, low symmetry systems
Authors: Peterson V. K.
Published: March 2005

The measurement of lattice parameters using the Le Bail method was shown to be inappropriate for a complex, low symmetry, structure, even with high resolution synchrotron diffraction data. The method failed as a result of ambiguous indexing in the absence of constraints on diffraction intensities, that arise when a structural model is used, combined with the large number of reflections. A caution for the use of the Le Bail and other whole-powder pattern decomposition methods is presented, particularly for high reflection density data.
Racial Misclassification and Disparities in Cardiovascular Disease Among American Indians and Alaska Natives
Authors: Rhoades Dorothy A.
Published: March 2005

Background—

National vital event data suggest that cardiovascular disease (CVD) mortality rates are lower for American Indians and Alaska Natives (AIAN) than for the general US population, but these data are disproportionately flawed for AIAN because of racial misclassification.

Methods and Results—

Vital event data adjusted for racial misclassification and published by the Indian Health Service were used to compare trends in CVD mortality from 1989 to 1991 to 1996 to 1998 between AIAN, US all-races, and US white populations. Without misclassification accounted for, AIAN initially had the lowest mortality rates from major CVD, but by the end of the study, their rates were the highest. Adjustment for misclassification revealed an early and rapidly growing disparity between CVD mortality rates among AIAN compared with rates in the US all-races and white populations. By 1996 to 1998, the age- and misclassification-adjusted number of CVD deaths per 100 000 among AIAN was 195.9 compared with age-adjusted rates of 166.1 and 159.1 for US all races and whites, respectively. The annual percent change in CVD mortality for AIAN was 0.5 compared with −1.8 in the other groups. Regardless of racial misclassification, the most striking and widening disparities were found for middle-aged AIAN, but CVD mortality among AIAN ≥65 years of age was lower than in the other populations.

Conclusions—

A previously underrecognized disparity in CVD mortality exists for AIAN, particularly among middle-aged adults. Moreover, these disparities are increasing. Efforts to reduce CVD mortality in AIAN must begin before the onset of middle age.
Eliminating Disparities in Cardiovascular Health
Authors: Mensah George A.
Published: March 2005

Disparities in cardiovascular health are among the most serious public health problems in the United States today. Despite the remarkable declines in cardiovascular mortality observed nationally over the last 3 decades, many population subgroups defined by race, ethnicity, gender, socioeconomic status, educational level, or geography show striking, and often widening, disparities in cardiovascular health. The pervasive nature of these disparities and compelling evidence of the adverse impact they have on clinical outcomes and quality of life have been well documented. The elimination of these disparities is 1 of the 2 overarching goals of the
Healthy People 2010
national public health agenda; however, few publications provide guidance on what actions to take. In this review, 6 strategic imperatives within a framework for action are presented. Other key elements of the framework include 10 focal areas and 6 major settings within which the framework calls for accelerated interventions to eliminate disparities in cardiovascular health. Success in this endeavor will require innovative and comprehensive interventions built on a foundation of sound clinical and public health science. Strategic partnerships with communities, community-based organizations, state and local governments, and public and private partners from both health and nonhealth sectors are essential. Additionally, investment in local-level disparities surveillance, community-based participatory research, and development of a diverse clinical and public health workforce will be invaluable.
Creating Walk-Through Images from a Video Sequence of a Dynamic Scene
Authors: Kang Hyung W. , Shin Sung Yong
Published: March 2005

Tour into the picture (TIP), proposed by Horry et al. (Horry, Anjyo, & Arai, 1997, ACM SIGGRAPH '97 Conference Proceedings, 225–232) is a method for generating a sequence of walk-through images from a single reference image. By navigating a 3D scene model constructed from the image, TIP provides convincing 3D effects. This paper presents a comprehensive scheme for creating walk-through images from a video sequence by generalizing the idea of TIP. To address various problems in dealing with a video sequence rather than a single image, the proposed scheme is designed to have the following features: First, it incorporates a new modeling scheme based on a vanishing circle identified in the video, assuming that the input video contains a negligible amount of motion parallax effects and that dynamic objects move on a flat terrain. Second, we propose a novel scheme for automatic background detection from the video, based on 4-parameter motion model and statistical background color estimation. Third, to assist the extraction of static or dynamic foreground objects from video, we devised a semiautomatic boundary-segmentation scheme based on enhanced lane (Kang & Shin, 2002, Graphical Models, 64 (5), 282–303). The purpose of this work is to let users experience the feel of navigating into a video sequence with their own interpretation and imagination about a given scene. The proposed scheme covers various types of video films of dynamic scenes, such as sports coverage, cartoon animation, and movie films, in which objects are continuously changing their shapes and locations. It can also be used to produce a variety of synthetic video sequences by importing and merging dynamic foreign objects with the original video.
A Framework for Building and Deploying the Multiparty Audio Service for Collaborative Environments
Authors: Radenkovic Milena
Published: March 2005

Distributed partial mixing (DPM) is an approach to creating a distributed audio service that supports optimization of bandwidth utilization across multiple related audio streams (e.g., from concurrently active audio sources) while maintaining fairness to TCP traffic in best-effort networks. Rate adaptation of streamed audio is difficult because of its rate sensitivity, the relatively limited range of encoding bandwidths available, and the potential impact on the end user of rate-adaptation artifacts (such as changes of encoding). This paper describes and demonstrates how our design combines TCP-fairness with the stability that is desirable for streaming audio and other rate-sensitive media. In particular, our design combines: a distributed multi-stream management/mixing architecture, loss-event and round-trip time monitoring, rate limiting based on a TCP rate equation, tuned increase and decrease strategies, and a loss-driven network-probing mode. Experimental validation is performed against TCP and independent DPM traffic. In particular, we summarize and discuss the two contrasting models for deploying DPM within the context of large dynamic environments that we introduced in Radenkovic and Greenhalgh (2002), Proceedings of ACM VRST 2002, 179–185. We argue that the DPM paradigm remains feasible and desirable in such environments.
Nā⋅iruddīn al-Albānī on Muslim's Sahīh: A Critical Study of His Method
Authors: Amin Kamaruddin
Published: March 2005

Nā⋅iruddīn al-Albānī (d. 1999) was a Muslim autodidact who devoted most of his life to the close study of prophetic hadīths. al-Albānī classified as weak hundreds of hadīths considered authentic by most Muslim scholars, including some hadīth s found in the Sahīh of Muslim. In this essay, I explain al-Albānī's method of determining that a hadīth is either authentic or spurious; d iscuss the implications of his method when applied to other hadīths; and examine the hadīths declared weak by al-Albānī from the perspective of both the traditional hadīth sciences and non-Muslim methods of dating a hadīth. Based on an analysis of 360 hadīths found in the canonical collections that were transmitted by Abū al-Zubayr from Jābir, I argue that Muslim did not regard the transmission terminology u sed by the Successors as a decisive criterion for determining whether or not a transmitter is reliable. This argument calls into question al-Albānī's method, for he used terminology as the decisive criterion for assessing the validity of transmissions. Our reexamination of one hadīth declared weak by al-Albānī, called here the Abū al-Zubayr hadīth , leads us to question the historicity of at least 125 of his hadīths in M uslim's Sahīh.
When Categorization Is Ambiguous: Factors That Facilitate the Use of a Multiple Category Inference Strategy
Authors: Gregan‐Paxton Jennifer , Hoeffler Steve , Zhao Min
Published: March 2005

Prior research has established that categorization plays a central role in new product learning. Very little is known, however, about category‐based learning under conditions of categorization ambiguity. Of particular interest is whether and under what circumstances consumers might employ a multiple‐ (vs. single‐) category strategy to generate inferences about ambiguous products. In this research, we identified 2 factors—category familiarity and the nature of the category cue—that are responsible for determining whether inferences are based on a single category or multiple, competing categories. The results of 3 studies suggest that when an ambiguous product is described in terms of conflicting conceptual and perceptual category cues, a single category inference strategy is employed when the perceptually cued category is more familiar than the conceptually cued category. In particular, inferences are based largely on the perceptually cued category under these circumstances. However, when the perceptually cued category is less than or equal to the conceptually cued category in familiarity, a multiple category inference strategy is employed and inferences are based on both the perceptually and conceptually cued categories.
Additive Effects of the PPARγ, APOE, and FABP-2 Genes in Increasing Daylong Triglycerides of Normolipidemic Women to Concentrations Comparable to Those in Men
Authors: Ribalta Josep , Halkes Constantijn JM , Salazar Juliana , Masana Lluís , Cabezas Manuel Castro
Published: March 2005

Background: Fasting and postprandial triglyceride (TG) concentrations vary considerably among individuals. TG metabolism is more efficient in women than in men, which may partly explain why females are protected against atherosclerosis. Our aim was to identify gender-specific genetic influences on fasting and postprandial TG concentrations under typical living conditions in healthy, lean, normolipidemic women.

Methods: We studied 40 women and 48 men. Diurnal capillary TG profiles were calculated as the integrated area under the capillary TG curve averaged over 3 days. Genotypes of the FABP-2, HL, LPL, APOE, and PPARγ genes and the APOC-III, APOC-III/A-IV intergenic region were determined.

Results: Three genes (FABP-2, APOE, and PPARγ) had a significant additive effect only in women. Mean TG concentrations were fourfold higher in women carriers of the PPARγ wild-type allele (P = 0.044), threefold higher in carriers of the rare FABP-2 allele (P = 0.006), and fivefold higher in carriers of the E2 allele of the APOE gene (P = 0.037) than in noncarriers. None of these effects was observed in men. The presence of two or more of these adverse alleles increased TG concentrations in a dose-dependent manner. Women carriers of three adverse alleles had postprandial TG values comparable to those for men.

Conclusions: An adverse combination of common alleles of the FABP-2, APOE, and PPARγ genes in women increases their TG concentrations to values comparable to those seen in men. Although this influence is not appreciable when studying fasting plasma TGs, it becomes apparent with use of a more sensitive index such as measurements made throughout the day.
Identity in a Post‐Communist Balkan State: An Albania Village Study
Authors: Young Antonia
Published: March 2005

Identity in. Post‐Communist Balkan State: An Albania Village Study. Douglas Saltmarshe .Ashgate: Aldershot, Burlington USA, Singapore, Sydney, 2001. 237pp.