bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Hyperfine Structure of the Rotational Spectra of XYZ3-Type Molecule, Where Nuclei Z Have Electric Quadrupole Moments
Authors: Mizushima Masataka , Ito Takashi
Published: January 2005

Hyperfine structure due to the electric quadrupole moments of nuclei is calculated for a special molecule of XYZ3 type, where nucleus Z has a spin larger than 1/2, and nuclei X and Y have no electric quadrupole moments. The number of the hyperfine structural lines is calculated group-theoretically for the cases where I1=1, 3/2, 2, 5/2, I1 being the spin of nucleus Z. The theoretical spectra of the J=0→1 transition are given for these cases.
The Statistical Mechanical Theory of Solutions. I
Authors: Kirkwood John G. , Buff Frank P.
Published: January 2005

A general statistical mechanical theory of solutions is developed with the aid of the theory of composition fluctuations in the grand canonical ensemble. It is shown that the derivatives of the chemical potentials and osmotic pressure with respect to concentrations, the partial molar volumes, and compressibility may be expressed in terms of integrals of the radial distribution functions of the several types of molecular pairs present in the solution. Explicit coefficients of a q-fraction expansion of the thermodynamic variables are presented in a detailed treatment of the two-component system.
Substituted Methanes. VI. Force Constants and Calculated Thermodynamic Properties for Some Trifluoromethanes
Authors: Decker Charlotte E. , Meister Arnold G. , Cleveland Forrest F.
Published: January 2005

Using previous Raman and infrared data, force constants were calculated for CF4, CF3H, and CF3Cl, by means of the Wilson FG matrix method, with a potential energy function containing all possible second-degree terms. Fundamental frequencies for CF3D were then determined by means of the force constants found for CF3H. Finally, the heat content, free energy, entropy, and heat capacity for the ideal gaseous state at 1 atmos pressure were calculated for these 4 molecules for 11 temperatures, from 100°K to 1000°K, with a rigid rotator, harmonic oscillator approximation.
The Magnetic Susceptibility of Uranium Tetrachloride
Authors: Stoenner R. , Elliott N.
Published: January 2005

The magnetic susceptibility of UCl4 has been measured in the temperature range 76°—354°K. The molar susceptibility is given by the equation, χmole=1.22/(T+39∘).
The Parallel Vibrations of Linear Triatomic Molecules
Authors: Thomas W. J. Orville
Published: January 2005

The possible solutions of the valence force potential constants occurring in the potential function for the stretching modes of some triatomic molecules are found; these are found as functions of a parameter p related to the coordinates describing the parallel modes of vibration.

The form of the normal modes and the potential energy distribution corresponding to a particular set of constants for each molecule is obtained.
Free Volumes and Free Angle Ratios of Molecules in Liquids
Authors: Kincaid John F. , Eyring Henry
Published: January 2005

The free volume is defined as the total integral over that part of the potential energy of the molecule in the liquid which is due to thermal displacements of the center of gravity of the molecule from its equilibrium position. The free angle is the corresponding integral over angular displacements of the molecule. The free volume, Vf is related to the velocity of sound, u, in the liquid by u(liquid)=u (gas) (V/Vf)13.This equation is used to derive a formula connecting the sound velocity in the liquid with its thermal conductivity. The quantity, RT/p exp (ΔH/RT), gives the product of the free angle ratio and the free volume, rather than the free volume itself. Here p is the vapor pressure and ΔH is the heat of vaporization. The free volumes from sound velocities agree with those determined by independent methods. Specific heats, entropies of vaporization, the spectroscopic observations of Cartwright, and the differences between sound velocity, free volumes and the function RT/p ×exp (ΔH/RT) are examined from the point of view of restricted rotation of the molecules in liquids. Lack of free rotation of molecules suffices to explain the abnormalities of the liquids examined. The dielectric constants of polar liquids are interpreted assuming restricted rotation and the following formula is derived: μl2μg−2=1−((1−cos θ1)/2)2,where μl is the apparent dipole moment of the molecule in the liquid, μg is the dipole moment as determined from measurements in the gas phase, and θ1, is the polar angle related to the free angle ratio, δ2, by δ2=(1−cos θ1)/2.The concept of restricted rotation of the molecules in the liquid accounts satisfactorily for the observed dielectric polarizations of water and methyl alcohol.
Order and Disorder in Binary Solid Solutions
Authors: Kirkwood John G.
Published: January 2005

A theory of order and disorder in solid solutions, based upon a direct evaluation of the crystalline partition function, is described. As in the theory of Bethe, the fluctuation in energy within states of a fixed degree of order, is taken into account. The method promises to be of use in the study of other cooperative phenomena.
Statistical Mechanics of Condensing Systems. III
Authors: Mayer Joseph E. , Harrison S. F.
Published: January 2005

A general development of the Gibbs phase integral for a system of chemically saturated molecules gives equations for the thermodynamic properties of the system. The equations predict the usual condensation phenomenon of the gas to form a condensed phase with a surface tension at temperatures below a characteristic temperature Tm. At Tm the surface tension of the condensed phase is zero, and this phase undergoes a discontinuous change without heat of transition. Between Tm and the true critical temperature Tc, there exists a finite volume interval for which P and the Gibbs free energy F is independent of the volume. Above Tc the usual P—V diagram predicted above the critical point is found, with no volume for which (∂P/∂V)T is zero.
Exchange Reactions with Deuterium II. The Photochemical Exchange Between Deuterium and Hydrogen Chloride
Authors: Leighton Philip A. , Cross Paul C.
Published: January 2005

The exchange reaction between hydrogen chloride and deuterium, initiated photochemically, is found to be a chain reaction with quantum yields ranging from 2 to 19 under the experimental conditions employed. The rate determining step is the reaction Cl+D2→DCl+D. The proportions at the photostationary state are shifted from those at thermal equilibrium in a direction which indicates a somewhat stronger absorption by HCl than by DCl in the region 2000–2150A.
Comparison of Exciton and Molecular Orbital Calculations on n→π* Transitions
Authors: Kearns David R. , El-Bayoumi M. Ashraf
Published: January 2005

In this paper we have compared the application of the exciton and the molecular orbital methods to the calculation of n→π* transitions in N-heteroaromatic molecules. A number of the features of the n→π* transitions were treated by these two methods, including energies of the (n, π*) states, the intensities of the allowed n→π* transitions, the ordering of the allowed and forbidden transitions and singlet-triplet splittings. From a comparison of experiment and theory, it is concluded that the assumption, which is made in the exciton calculations, that n→π* transitions are essentially localized ``atomic-like'' transitions, is a poor initial approximation and leads to a number of incorrect predictions. The assumption that the promoted lone-pair electron is delocalized over the pi-aromatic system appears to be a much better initial approximation, and when the effect of electron repulsion between lone-pair electrons is included in the MO calculations, there is very good agreement between the theoretical predictions and experimental observations on n→π* transition in the mono- and polycyclic azines. The relation between MO theory in the one-electron approximation and MO theory in which electron repulsion between the lone-pair electrons has been included and is also discussed.
Absorption Spectrum of Gaseous F- and Electron Affinities of the Halogen Atoms
Authors: Berry R. Stephen , Reimann Curt W.
Published: January 2005

The absorption spectrum of gaseous fluoride ion has been observed in shock-heated vapors of CsF, RbF, and KF. The spectrum is a continuum with two sharp thresholds at 3595 and 3542 Å, similar to those of the other halide ions. The electron affinity determined from the low-energy threshold is 3.448±0.005 eV. The cross-section for photodetachment at 3565 Å is about 2.5±2×10−18 cm2 and at 3525, about 3.3±2×10−18 cm2. The electron affinities of chlorine, bromine and iodine are revised, respectively, to 3.613, 3.363, and 3.063 eV, all with uncertainties of 0.003 eV.
Dielectric Friction on a Moving Ion
Authors: Zwanzig Robert
Published: January 2005

A recent derivation by R. H. Boyd of the frictional force on a slowly moving ion due to dielectric loss in the surrounding medium is corrected and generalized.
Catalytic growth of group III-nitride nanowires and nanostructures by metalorganic chemical vapor deposition
Authors: Su J. , Cui G. , Gherasimova M. , Tsukamoto H. , Han J. , Ciuparu D. , Lim S. , Pfefferle L. , He Y. , Nurmikko A. V. , Broadbridge C. , Lehman A.
Published: January 2005

We report flexible synthesis of group III–nitride nanowires and nanostructures by metalorganic chemical vapor deposition (MOCVD) via a catalytic vapor-liquid-solid (VLS) growth mechanism. Supersaturation and surface stoichiometry strongly influence the stability of liquid droplets and growth selectivity. To facilitate and sustain the VLS growth, indium catalyst is introduced based on thermodynamic consideration. The employment of mesoporous molecular sieves (MCM-41) helps to prevent the coalescence of catalyst droplets and to promote nucleation statistics. Both GaN and AlN nanowires have been synthesized using MOCVD. Three-dimensional AlN∕GaN trunk-branch nanostructures are reported to illustrate the versatility of incorporating the VLS mechanism into MOCVD process.
High mobility transparent thin-film transistors with amorphous zinc tin oxide channel layer
Authors: Chiang H. Q. , Wager J. F. , Hoffman R. L. , Jeong J. , Keszler D. A.
Published: January 2005

Transparent thin-film transistors (TTFTs) with an amorphous zinc tin oxide channel layer formed via rf magnetron sputter deposition are demonstrated. Field-effect mobilities of 5–15 and 20–50cm2V−1s−1 are obtained for devices post-deposition annealed at 300 and 600°C, respectively. TTFTs processed at 300 and 600°C yield devices with turn-on voltage of 0–15 and −5–5V, respectively. Under both processing conditions, a drain current on-to-off ratio greater than 107 is obtained. Zinc tin oxide is one example of a new class of high performance TTFT channel materials involving amorphous oxides composed of heavy-metal cations with (n−1)d10ns0 (n⩾4) electronic configurations.
Vacancy concentrations in silicon determined by the indiffusion of iridium
Authors: Lerner L. , Stolwijk N. A.
Published: January 2005

Diffusion of Ir into Si was investigated in the temperature range from 875 to 1050 °C by means of neutron activation analysis and mechanical sectioning. Within the framework of interstitial-substitutional diffusion, previously established for Ir in Si, the measured penetration profiles were simulated by the simultaneous action of the kick-out mechanism and the dissociative mechanism. This enabled us to assess Si vacancy concentrations in thermal equilibrium.
Superconductivity controlled by polarization in field-effect devices of confined geometry
Authors: Pavlenko Natalia , Schwabl Franz
Published: January 2005

We propose a concept for superconducting electric field-effect devices based on superconducting films sandwiched between ferroelectric layers. We provide theoretical calculations that indicate how the field effect in these devices could be amplified, which can be experimentally probed even at the current stage of film fabrication techniques.
A genetic approach to thede novoidentification of targets of strain-specific immunity in malaria parasites
Authors: Martinelli Axel , Cheesman Sandra , Hunt Paul , Culleton Richard , Raza Ahmed , Mackinnon Margaret , Carter Richard
Published: January 2005

Vaccine research in malaria has a high priority. However, identification of specific antigens as candidates for vaccines against asexual blood stages of malaria parasites has been based on largely circumstantial evidence. We describe here how genes encoding target antigens of strain-specific immunity in malaria can be directly located in the parasite's genome without prior information concerning their identity, by the method we call linkage group selection. Two genetically distinct clones of the rodent malaria parasitePlasmodium chabaudi chabaudi, each of which induces an immunity in laboratory mice that is more protective against challenge with itself than with the heterologous strain, were genetically crossed, and the uncloned cross progeny selected in mice that had been made partially immune by infection and drug cure with one or the other parental strain. Proportions of parental alleles in the selected and unselected cross progeny were compared by using quantitative genome-wide molecular markers. A small number, including groups of linked markers forming so-called selection valleys, were markedly reduced under strain-specific immune pressure. A very prominent selection valley was found to contain the gene for merozoite surface protein-1, a major candidate antigen for malaria vaccine development, at the locus at which the strongest reduction under strain-specific immune selection was detected. Closely linked to the merozoite surface protein-1 gene was a gene containing the signature motif of the ring-infected erythrocyte surface antigen family. Another affected locus, unlinked to this selection valley, contained a member of the serine repeat antigen gene family.
Diversity–productivity relationships: Initial effects, long-term patterns, and underlying mechanisms
Authors: van Ruijven Jasper , Berendse Frank
Published: January 2005

A common pattern emerging from studies on the relationship between plant diversity and ecosystem functioning is that productivity increases with diversity. Most of these studies have been carried out in perennial grasslands, but many lasted only two growing seasons or reported data from a single year. Especially for perennial plant communities, however, the long-term effects of diversity are important. The question whether interactions between few species or among many species lead to increased productivity remained largely unanswered. So far, the main mechanism addressed is the increased input of nitrogen by nitrogen-fixing legumes. We report that other mechanisms can also generate strong increases of productivity with diversity. Results from 4 consecutive years of a plant diversity experiment without legumes show that a positive relationship between plant species richness and productivity emerged in the second year and strengthened with time. We show that increased nutrient use efficiency at high species richness is an important underlying mechanism. This mechanism had not been discussed in earlier studies. Furthermore, our results suggest that complementary nutrient uptake in space and time is important. Together, these mechanisms sustain consistently high productivity at high diversity.
Two cleavage products of the
Drosophila
accessory gland protein ovulin can independently induce ovulation
Authors: Heifetz Yael , Vandenberg Laura N. , Cohn Heather I. , Wolfner Mariana F.
Published: January 2005

Proteins and peptides in
Drosophila melanogaster
seminal fluid induce mated females to increase their rates of egg deposition. One seminal-fluid protein, ovulin (Acp26Aa), stimulates an early step in the egg-laying process, the release of oocytes by the ovary. Ovulin, upon transfer to females, is cleaved sequentially within the mated female's reproductive tract. Here, we show that systemic ectopic expression of ovulin is sufficient to stimulate ovulation in unmated females. By using this assay to assess the functionality of ovulin's cleavage products, we find that two of the four cleavage products of ovulin can stimulate ovulation independently. Thus, ovulin's cleavage in mated females is not destructive and instead may liberate additional functional products with potential to modulate ovulation independently.
The carboligation reaction of acetohydroxyacid synthase II: Steady-state intermediate distributions in wild type and mutants by NMR
Authors: Tittmann Kai , Vyazmensky Maria , Hübner Gerhard , Barak Ze'ev , Chipman David M.
Published: January 2005

The thiamin diphosphate (ThDP)-dependent enzyme acetohydroxyacid synthase (AHAS) catalyzes the first common step in branched-chain amino acid biosynthesis. By specific ligation of pyruvate with the alternative acceptor substrates 2-ketobutyrate and pyruvate, AHAS controls the flux through this branch point and determines the relative rates of synthesis of isoleucine, valine, and leucine, respectively. We used detailed NMR analysis to determine microscopic rate constants for elementary steps in the reactions of AHAS II and mutants altered at conserved residues Arg-276, Trp-464, and Met-250. In Arg276Lys, both the condensation of the enzyme-bound hydroxyethyl-ThDP carbanion/enamine (HEThDP) with the acceptor substrates and acetohydroxyacid release are slowed several orders of magnitude relative to the wild-type enzyme. We propose that the interaction of the guanidinium moiety of Arg-264 with the carboxylate of the acceptor ketoacid provides an optimal alignment of substrate and HEThDP orbitals in the reaction trajectory for acceptor ligation, whereas its interaction with the carboxylate of the covalent HEThDP-acceptor adduct plays a similar role in product release. Both Trp-464 and Met-250 affect the acceptor specificity. The high preference for ketobutyrate in the wild-type enzyme is lost in Trp464Leu as a consequence of similar forward rate constants of carboligation and product release for the alternative acceptors. In Met250Ala, the turnover rate is determined by the condensation of HEThDP with pyruvate and release of the acetolactate product, whereas the parallel steps with 2-ketobutyrate are considerably faster. We speculate that the specificity of carboligation and product liberation may be cumulative if the former is not completely committed.
Notch-1 activation and dendritic atrophy in prion disease
Authors: Ishikura Nako , Clever Jared L. , Bouzamondo-Bernstein Essia , Samayoa Erik , Prusiner Stanley B. , Huang Eric J. , DeArmond Stephen J.
Published: January 2005

In addition to neuronal vacuolation and astrocytic hypertrophy, dendritic atrophy is a prominent feature of prion disease. Because increased Notch-1 expression and cleavage releasing its intracellular domain (NICD) inhibit both dendrite growth and maturation, we measured their levels in brains from mice inoculated with Rocky Mountain Laboratory (RML) prions. The level of NICD was elevated in the neocortex, whereas the level of β-catenin, which stimulates dendritic growth, was unchanged. During the incubation period, levels of the disease-causing prion protein isoform, PrP
Sc
, and NICD increased concomitantly in the neocortex. Additionally, increased levels of Notch-1 mRNA and translocation of NICD to the nucleus correlated well with regressive dendritic changes. In scrapie-infected neuroblastoma (ScN2a) cells, the level of NICD was elevated compared with uninfected control (N2a) cells. Long neurofilament protein-containing processes extended from the surface of N2a cells, whereas ScN2a cells had substantially shorter processes. Transfection of ScN2a cells with a Notch-1 small interfering RNA decreased Notch-1 mRNA levels, diminished NICD concentrations, and rescued the long process phenotype. These results suggest that PrP
Sc
in neurons and in ScN2a cells activates Notch-1 cleavage, resulting in atrophy of dendrites in the CNS and shrinkage of processes on the surface of cultured cells. Whether diminishing Notch-1 activation
in vivo
can prevent or even reverse neurodegeneration in prion disease remains to be established.
Maize diversity and ethnolinguistic diversity in Chiapas, Mexico
Authors: Perales Hugo R. , Benz Bruce F. , Brush Stephen B.
Published: January 2005

The objective of this study is to investigate whether ethnolinguistic diversity influences crop diversity. Factors suggest a correlation between biological diversity of crops and cultural diversity. Although this correlation has been noted, little systematic research has focused on the role of culture in shaping crop diversity. This paper reports on research in the Maya highlands (altitude > 1,800 m) of central Chiapas in southern Mexico that examined the distribution of maize (Zea mays) types among communities of two groups, the Tzeltal and Tzotzil. The findings suggest that maize populations are distinct according to ethnolinguistic group. However, a study of isozymes indicates no clear separation of the region's maize into two distinct populations based on ethnolin-guistic origin. A reciprocal garden experiment shows that there is adaptation of maize to its environment but that Tzeltal maize sometimes out-yields Tzotzil maize in Tzotzil environments. Because of the proximity of the two groups and selection for yield, we would expect that the superior maize would dominate both groups' maize populations, but we find that such domination is not the case. The role of ethnolinguistic identity in shaping social networks and information exchange is discussed in relation to landrace differentiation.
Epstein-Barr virus nuclear antigen 1 does not induce lymphoma in transgenic FVB mice
Authors: Kang Myung-Soo , Lu Hongxiang , Yasui Teruhito , Sharpe Arlene , Warren Henry , Cahir-McFarland Ellen , Bronson Roderick , Hung Siu Chun , Kieff Elliott
Published: January 2005

The lymphoma-inducing potential of Ig heavy-chain enhancer- and promoter-regulated Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1) was evaluated in three transgenic FVB mouse lineages. EBNA1 was expressed at a higher level in transgenic B220(+) splenocytes than in EBV-infected lymphoblastoid cell lines. EBNA1 was also expressed in B220(-) transgenic splenocytes and thymocytes. Before killing and assessments at 18-26 months, EBNA1-transgenic mice did not differ from control mice in mortality. At 18-26 months EBNA1-transgenic mice did not differ from littermate control in ultimate body weight, in spleen size or weight, in lymph node, kidney, liver, or spleen histology, in splenocyte fractions positive for cluster of differentiation (CD)3ε, CD4, CD8, CD62L, B220, CD5, IgM, IgD, MHC class II, CD11b, or CD25, or in serum IgM, IgG, or total Ig levels. Lymphomas were not found in spleens or other organs of 18- to 26-month-old EBNA1-transgenic (
n
= 86) or control (
n
= 45) FVB mice. EBNA1-transgenic lineages had a higher pulmonary adenoma prevalence than did littermate controls (39% versus 7%). However, the adenoma prevalence was not higher in EBNA1-transgenic mice than has been described for FVB mice, and EBNA1 was not expressed in normal pulmonary epithelia or adenomas.
Menin and MLL cooperatively regulate expression of cyclin-dependent kinase inhibitors
Authors: Milne Thomas A. , Hughes Christina M. , Lloyd Ricardo , Yang Zhaohai , Rozenblatt-Rosen Orit , Dou Yali , Schnepp Robert W. , Krankel Cynthia , LiVolsi Virginia A. , Gibbs Denise , Hua Xianxin , Roeder Robert G. , Meyerson Matthew , Hess Jay L.
Published: January 2005

Mutations in the
MEN1
gene are associated with the multiple endocrine neoplasia syndrome type 1 (MEN1), which is characterized by parathyroid hyperplasia and tumors of the pituitary and pancreatic islets. The mechanism by which
MEN1
acts as a tumor suppressor is unclear. We have recently shown that menin, the
MEN1
protein product, interacts with mixed lineage leukemia (MLL) family proteins in a histone methyltransferase complex including Ash2, Rbbp5, and WDR5. Here, we show that menin directly regulates expression of the cyclin-dependent kinase inhibitors

p27
Kip1

and

p18
Ink4c

. Menin activates transcription by means of a mechanism involving recruitment of MLL to the

p27
Kip1

and

p18
Ink4c

promoters and coding regions. Loss of function of either MLL or menin results in down-regulation of

p27
Kip1

and

p18
Ink4c

expression and deregulated cell growth. These findings suggest that regulation of cyclin-dependent kinase inhibitor transcription by cooperative interaction between menin and MLL plays a central role in menin's activity as a tumor suppressor.
Endothelial nitric oxide synthase activation is critical for vascular leakage during acute inflammation
in vivo
Authors: Bucci Mariarosaria , Roviezzo Fiorentina , Posadas Inmaculada , Yu Jun , Parente Luca , Sessa William C. , Ignarro Louis J. , Cirino Giuseppe
Published: January 2005

The role of endothelium-derived nitric oxide (NO) in acute inflammation is not known. Here, we examine acute inflammation in congenic endothelial NO synthase-deficient (eNOS
-/-
) mice. Intraplantar injection of carrageenan induces a biphasic inflammatory response. The early phase (0-6 h) is largely eliminated, and the secondary phase (24-96 h) is markedly reduced in eNOS
-/-
but not WT mice. Inhibition of phosphatidylinositol 3-kinase or hsp90, pathways upstream of eNOS activation, also reduces carrageenan-stimulated edema formation. To separate the ability of eNOS to regulate leukocyte trafficking vs. vascular permeability, zymosan-stimulated leukocyte infiltration and protein extravasation were assessed in WT and eNOS
-/-
mice. Zymosan increases inflammatory cell extravasation to the same extent in WT and eNOS
-/-
mice, whereas the extravasation of plasma protein is lower in eNOS
-/-
mice. Inhibition of phosphatidylinositol 3-kinase and hsp90 also blocks protein leakage, but not leukocyte influx. These data collectively support the critical role for eNOS in regulating the magnitude of the acute inflammatory response and show that eNOS is critical for regulating microcirculatory endothelial barrier function
in vivo
.
Clearance of hepatitis B virus from the liver of transgenic mice by short hairpin RNAs
Authors: Uprichard Susan L. , Boyd Bryan , Althage Alana , Chisari Francis V.
Published: January 2005

Hepatitis B virus (HBV) causes acute and chronic hepatitis and hepatocellular carcinoma. Although a preventive vaccine is available, the therapeutic options for chronically infected patients are limited. It has been shown that RNA interference can prevent HBV gene expression and replication
in vivo
when HBV expression vectors are delivered simultaneously with small interfering RNA (siRNA) or siRNA expression constructs. However, the therapeutic potential of siRNAs to interrupt ongoing HBV replication
in vivo
has not been established. Here, we show that expression of HBV-specific siRNAs in the liver of HBV transgenic mice by recombinant adenoviruses can suppress preexisting HBV gene expression and replication to almost undetectable levels for at least 26 days. These results demonstrate that efficiently delivered siRNAs should be able to silence HBV in chronically infected patients.
Pulse‐Splitting for Some Reaction‐Diffusion Systems in One‐Space Dimension
Authors: Kolokolnikov Theodore , Ward Michael J. , Wei Juncheng
Published: January 2005

Pulse‐splitting, or self‐replication, behavior is studied for some two‐component singularly perturbed reaction‐diffusion systems on a one‐dimensional spatial domain. For the Gierer‐Meinhardt model in the weak interaction regime, characterized by asymptotically small activator and inhibitor diffusivities, a numerical approach is used to verify the key bifurcation and spectral conditions of Ei et al. [Japan. J. Indust. Appl. Math., 18, (2001)] that are believed to be essential for the occurrence of pulse‐splitting in a reaction‐diffusion system. The pulse‐splitting that is observed here is edge‐splitting, where only the spikes that are closest to the boundary are able to replicate. For the Gray–Scott model, it is shown numerically that there are two types of pulse‐splitting behavior depending on the parameter regime: edge‐splitting in the weak interaction regime, and a simultaneous splitting in the semi‐strong interaction regime. For the semi‐strong spike interaction regime, where only one of the solution components is localized, we construct several model reaction‐diffusion systems where all of the pulse‐splitting conditions of Ei et al. can be verified analytically, yet no pulse‐splitting is observed. These examples suggest that an extra condition, referred to here as the multi‐bump transition condition, is also required for pulse‐splitting behavior. This condition is in fact satisfied by the Gierer–Meinhardt and Gray–Scott systems in their pulse‐splitting parameter regimes.
Uncertainty Quantification for Systems with Random Initial Conditions Using Wiener–Hermite Expansions
Authors: Rubinstein Robert , Choudhari Meelan
Published: January 2005

A number of engineering problems, including laminar‐turbulent transition in convectively unstable flows, require predicting the evolution of a nonlinear dynamical system under uncertain initial conditions. The method of Wiener–Hermite expansion is an attractive alternative to modeling methods, which solve for the joint probability density function of the stochastic amplitudes. These problems include the “curse of dimensionality” and closure problems. In this paper, we apply truncated Wiener–Hermite expansions with both fixed and time‐varying bases to a model stochastic system with three degrees of freedom. The model problem represents the combined effects of quadratic nonlinearity and stochastic initial conditions in a generic setting and occurs in related forms in both classical dynamics, turbulence theory, and the nonlinear theory of hydrodynamic stability. In this problem, the truncated Wiener–Hermite expansions give a good account of short‐time behavior, but not of the long‐time relaxation characteristic of this system. It is concluded that successful application of truncated Wiener–Hermite expansions may require special adaptations for each physical problem.
Short‐Lived Large‐Amplitude Pulses in the Nonlinear Long‐Wave Model Described by the Modified Korteweg–De Vries Equation
Authors: Grimshaw Roger , Pelinovsky Efim , Talipova Tatiana , Ruderman Michael , Erdélyi Róbert
Published: January 2005

The appearance and disappearance of short‐lived large‐amplitude pulses in a nonlinear long wave model is studied in the framework of the modified Korteweg–de Vries equation. The major mechanism of such wave generation is modulational instability leading to the generation and interaction of the breathers. The properties of breathers are studied both within the modified Korteweg–de Vries equation, and also within the nonlinear Schrödinger equations derived by an asymptotic reduction from the modified Korteweg–de Vries for weakly nonlinear wave packets. The associated spectral problems (AKNS or Zakharov‐Shabat) of the inverse‐scattering transform technique also are utilized. Wave formation due to this modulational instability is investigated for localized and for periodic disturbances. Nonlinear‐dispersive focusing is identified as a possible mechanism for the formation of anomalously large pulses.
Culicoides midge trap enhancement with animal odour baits in Scotland
Authors: Mands V. , Kline D. L. , Blackwell A.
Published: January 2005

Abstract.  Examples of the commercial trap Mosquito Magnet® Pro™ (MMP emitting attractant 1‐octen‐3‐ol in carbon dioxide 500 mL/min generated from propane fuel), were run 24 h/day on the Isle of Skye, Scotland, during June–August 2001 and evaluated for catching Culicoides biting midges (Diptera: Ceratopogonidae). From 30 days trapping, the catch averaged 2626 ± 1358 Culicoides females/trap/day (mean ± SE, range 558 ± 139 to 6088 ± 3597, for five sets of six consecutive nights), predominantly the pest Culicoides impunctatus Goetghebuer (68% overall), plus C. vexans (Stæger) > C. delta Edwards > C. pulicaris (L.) > C. lupicaris Downs & Kettle > C. albicans (Winnertz) > other Culicoides spp.

Attempts were made to enhance the odour baiting system by adding hexane‐extracts (2.1 mg/day) of hair samples from large host animals, resulting in the following effects on Culicoides collections: sheep − 53 %, red deer − 26 %, calf + 20%, pony + 40%, water buffalo + 262%, with greatest increases for C. impunctatus and C. pulicaris.

Serial concentrations of these animal extracts (10−1 − 10−3 × 2.2 g/mL) were assayed on parous female C. impunctatus response in a Y‐tube olfactometer (air‐flow 150 mL/min), and by electroantennogram (EAG) on Culicoides nubeculosus Meigen laboratory‐reared parous females. Positive behavioural responses to host odours were dose‐dependent: the water buffalo extract being most active (threshold 0.22 g/mL), similar to deer, whereas other host extracts were ≥ 10‐fold less active. Correspondingly, the EAG threshold was lowest for water buffalo, 10‐fold greater for deer, calf and pony, but not detected for sheep. If the active component(s) of these host extracts can be identified and synthesized, they might be employed to improve the capture of Culicoides midges for local control by removal trapping.
Species abundance and insecticide resistance of Anopheles gambiae in selected areas of Ghana and Burkina Faso
Authors: Yawson A. E. , Mccall P. J. , Wilson M. D. , Donnelly M. J.
Published: January 2005

Abstract.  The Ghanaian National Malaria Control Programme has prioritized insecticide‐treated materials as a key strategy for malaria control. We report on a survey of the distribution of the molecular forms of Anopheles gambiae Giles (Diptera: Culicidae) and insecticide resistance (the kdr mutation), carried out by sampling mosquitoes from 11 locations in Ghana and one additional site in Burkina Faso. The molecular M and S forms of An. gambiae were found to occur in sympatry in southern Ghana. The S form predominated throughout its distribution in the coastal savannah, except at one location in the strand and mangrove zone where rice was cultivated. The M form was the only form collected in northern Ghana and was the predominant form (97.5%) in Burkina Faso. No M/S hybrids were detected. The kdr mutation was observed at very high frequencies (98–100%) within the S form but reached a maximum of only 3.38% in the M form in one population at an irrigation scheme in the Ghanaian coastal savannah zone.
Effect of food deprivation on response of the mite, Dermanyssus gallinae, to heat
Authors: Kilpinen O. , Mullens B. A.
Published: January 2005

Abstract.  Freshly blood‐fed adult females of the chicken mite Dermanyssus gallinae DeGeer (Acari: Dermanysidae) were food‐deprived during 1, 2–3, 8–10, 14–16 and 22–23 days. These mites were tested in groups of 10 to determine their sensitivity to a heat cue delivered for a 60 s period under controlled laboratory conditions (24°C, simulated dark conditions of 2 lx). Immobile mites were videotaped and start of activation (for individual mites) and percentage of mites activated in the 60 s period were related to temperature changes. Mites were activated with temperature gradients as low as 0.003–0.005°C/s. Mites that had fed the previous day had a significantly lower activation (20%) than other groups. Activation was highest at 2–3 days (60%) and 8–10 days (75%) post‐feeding. Activation declined significantly to 45% at 14–16 days and to 30% at 22–23 days post‐feeding. Activation patterns probably reflect mite physiological condition and declining responsiveness to heat cues concomitant with starvation and higher risks associated with activation in the prolonged absence of a host.
Could insecticide‐treated cattle reduce Afrotropical malaria transmission? Effects of deltamethrin‐treated Zebu onAnopheles arabiensisbehaviour and survival in Ethiopia
Authors: Habtewold T. , Prior A. , Torr S. J. , Gibson G.
Published: January 2005

Abstract. Anopheles arabiensisPatton (Diptera: Culicidae) is the most widespread vector of malaria in the Afrotropical Region. BecauseAn. arabiensisfeeds readily on cattle as well as humans, the insecticide‐treatment of cattle – as employed to control tsetse (Diptera: Glossinidae) and ticks (Acari: Ixodidae) – might simultaneously affect the malaria vectorial capacity of this mosquito. Therefore, we conducted field experiments in southern Ethiopia to establish whether Zebu cattle (Bos indicusL.) treated with a pour‐on pyrethroid formulation of 1% deltamethrin, widely used to control ticks and tsetse, would be effective againstAn. arabiensisor cause the female mosquitoes to feed more frequently on humans, due to behavioural avoidance of insecticide‐treated cattle. Contact bioassays (3 min exposure) showed that the insecticide remained effective for about 1 month (kill rate > 50%) against mosquitoes feeding on the flanks of treated cattle. A novel behavioural assay demonstrated thatAn. arabiensisreadily fed on insecticide‐treated cattle and were not deflected to human hosts in the presence of treated cattle. DNA‐fingerprinting of bloodmeals revealed thatAn. arabiensisnaturally feeds most frequently on older animals, consistent with the established practice of applying insecticide only to older cattle, while allowing younger untreated animals to gain immunity against infections transmitted by ticks. These encouraging results were tempered by finding that > 90% ofAn. arabiensis,An. pharoensisandAn. tenebrosusfemales feed on the legs of cattle, farthest from the site of pour‐on application along the animal's back and where the treatment may be least residual due to weathering. Observations of mosquitoes feeding naturally on insecticide‐treated cattle showed that the majority of wild female anophelines alighted on the host animal for less than 1 min to feed, with significantly shorter mean duration of feeding bouts on insecticide‐treated animals, and the effective life of the insecticide was only 1 week. Thus the monthly application of deltamethrin to cattle, typically used to control tsetse and ticks, is unlikely to be effective againstAn. arabiensispopulations or their vectorial capacity. Even so, it seems likely that far greater impact on anopheline mosquitoes could be achieved by applying insecticide selectively to the legs of cattle.
Competition between vectors of Chagas disease, Triatoma infestans and T. sordida: effects on fecundity and mortality
Authors: Oscherov E. B. , Damborsky M. P. , Bar M. E. , Gorla D. E.
Published: January 2005

Abstract.  Interspecific competition between two species of triatomine bugs (Hemiptera: Reduviidae), vectors of Chagas disease, was assessed for 16 months through comparative fecundity and mortality of experimental populations in chicken nests, maintained indoors with ambient conditions. Triatoma sordida (Stål), the secondary vector in north‐eastern Argentina, was compared with Triatoma infestans (Klug) the more widespread domestic vector in the southern cone of South America. Both species populations originated from females collected in 1995 from the community of Empedrado, Corrientes, Argentina. Three population units were monitored: T. infestans alone, T. sordida alone and both species together in equal proportions. Each population started with six male and six female adults, 116 eggs, and nymphal instars I to V numbering 82, 48, 16, 11 and 19, respectively. Numbers and weight of individual bugs were recorded monthly (August 1995 to December 1996). The pure populations of T. infestans and T. sordida showed temporal changes in abundance, rising in summer and falling in winter, similar to the typical trends under normal field conditions. In the mixed population, however, T. sordida fell to extinction after 6 months, whereas T. infestans reached similar abundance to the pure (control) population. For each nymphal instar of T. sordida, the mean body weight was significantly less and mortality rate was higher in the mixed population compared to the pure population, but there were no significant differences of adult longevity or fecundity between the pure and mixed populations of T. sordida. The apparent competitive displacement of T. sordida by T. infestans was attributed to the latter species having better ability to obtain bloodmeals. This might explain the rarity of mixed populations where these two species occur in sympatry.
The animal reservoir of Tunga penetrans in severely affected communities of north‐east Brazil
Authors: Heukelbach J. , Costa A. M. L. , Wilcke T. , Mencke N. , Feldmeier H.
Published: January 2005

Abstract.  Tungiasis is a zoonotic ectoparasitosis caused by the sand flea Tunga penetrans L. (Siphonaptera: Tungidae). This disease is hyperendemic in poor communities of north‐east Brazil, causing considerable morbidity in affected human populations, but the animal reservoirs have not been investigated previously in Brazil. To assess the prevalence and intensity of T. penetrans infection in domestic and peri‐domestic animals, as well as in the human population, we surveyed two typical communities of north‐east Brazil: an urban slum and a traditional fishing village. In the slum we examined 849 humans, 121 cats, 82 dogs, 2 pigs, 2 rabbits, 1 monkey and 56 rodents, comprising 34 rats (Rattus rattus L.) and 22 mice (Mus domesticus L). In the fishing village we examined 505 humans, 68 dogs, 37 cats, 7 donkeys, 4 cattle, 3 pigs and 1 monkey. Tungiasis was common among dogs and cats of both communities, with respective prevalence rates of 67.1% (95% CI: 55.8–77.1) and 30.9% (95% CI: 20.2–43.3) in dogs, 49.6% (95% CI: 40.4–58.8) and 32.4% (95% CI: 18.0–49.8) in cats. Slum rats were 41.2% (95% CI: 24.6–59.3) infested, but the other animals were not. Human prevalence rates were 54.4% (95% CI: 51.0–57.8) in the slum and 52.1% (95% CI: 47.6–56.5) in the fishing village. High prevalence rates (range 31–67%) of tungiasis in humans, pets and rats (but apparently not other animals) indicate the need for an eco‐epidemiological approach to control of this anthropo‐zoonotic problem.
Blood‐feeding of Tunga penetrans males
Authors: Witt L. H. , Linardi P. M. , Meckes O. , Schwalfenberg S. , Ribeiro R. A. , Feldmeier H. , Heukelbach J.
Published: January 2005

Abstract.  The jigger Tunga penetrans (Linnaeus, 1758: type‐species of the family Tungidae) is the smallest known species of flea (Siphonaptera), causing serious ectoparasitosis of humans and domestic animals. The adult female Tunga lodges in the epidermis of the mammalian host, grows by neosomy, becomes gravid and expels eggs. Relatively little is known about the free‐living male Tunga adults. Among impoverished communities of Fortaleza in north‐east Brazil, we observed T. penetrans males as well as females penetrating the skin of human hosts. After penetrating the epidermis for a few hours, evidently for capillary feeding from the dermis, males withdrew their mouthparts and crawled away, whereas the females remained completely embedded, hypertrophying to become gravid, eventually dying in situ after oviposition. Caged rats were placed on the sandy soil and examined periodically for Tunga infestation. On five rats we obtained 140 females embedded and we detected 75 males biting, with rat erythrocytes observed in the proventriculus and midgut of all five males dissected and examined microscopically. This confirms that T. penetrans males are hamatophagous ectoparasites of mammals.
Behavioural and electrophysiological responses of the malaria mosquito Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) to human skin emanations
Authors: Qiu Y. T. , Smallegange R. C. , Hoppe S. , Van Loon J. J. A. , Bakker E.‐J. , Takken W.
Published: January 2005

Abstract.  Behavioural and electrophysiological responses of Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) to human skin emanations collected on glass beads were studied using a dual‐port olfactometer and electroantannography. Glass beads to which skin emanations from human hands had been transferred elicited a level of attraction similar to a human hand. The attractiveness of these handled glass beads faded away 4 h after transfer onto the beads. Storage at −20°C for up to 8 weeks showed a decreased but still attractive effect of the beads. In a choice test between one individual and four others, the emanations from the reference individual were significantly more attractive in three out of four cases. The headspace of handled glass beads elicited a dose‐dependent EAG response. The substances causing EAG activity could be removed partially by dichloromethane, ethanol and pentane‐ether. Glass beads provide a suitable neutral substrate for the transfer of human odour to enable chemical analysis of the human skin emanations for identification of kairomones of anthropophilic mosquitoes.
Functional Fixedness in a Technologically Sparse Culture
Authors: German Tim P. , Barrett H. Clark
Published: January 2005

Problem solving can be inefficient when the solution requires subjects to generate an atypical function for an object and the object's typical function has been primed. Subjects become “fixed” on the design function of the object, and problem solving suffers relative to control conditions in which the object's function is not demonstrated. In the current study, such functional fixedness was demonstrated in a sample of adolescents (mean age of 16 years) among the Shuar of Ecuadorian Amazonia, whose technologically sparse culture provides limited access to large numbers of artifacts with highly specialized functions. This result suggests that design function may universally be the core property of artifact concepts in human semantic memory.
Constraining Theories of Embodied Cognition
Authors: Markman Arthur B. , Brendl C. Miguel
Published: January 2005

Influences of perceptual and motor activity on evaluation have led to theories of embodied cognition suggesting that putatively complex judgments can be carried out using only perceptual and motor representations. We present an experiment that revisited a movement-compatibility effect in which people are faster to respond to positive words by pulling a lever than by pushing a lever and are faster to respond to negative words by pushing than by pulling. We demonstrate that the compatibility effect depends on people's representation of their selves in space rather than on their physical location. These data suggest that accounting for embodied phenomena requires understanding the complex interplay between perceptual and motor representations and people's representations of their selves in space.
Superior Performance of Blind Compared With Sighted Individuals on Bimanual Estimations of Object Size
Authors: Smith Melissa , Franz Elizabeth A. , Joy Susan M. , Whitehead Kirsty
Published: January 2005

Five preliminary experiments on sighted individuals revealed marked overestimation on an object size-estimation task using a bimanual response. These experiments ruled out the possibility that overestimation was due to the mode of visual presentation (whether two-dimensional or three-dimensional), the input modality (visual or kinesthetic), or the influence of other visual cues. The main experiment then investigated whether these distortions are due to visual experience by using a variant of the same task to test 24 blind and 24 sighted control participants. Remarkably, the sighted control participants overestimated object size, on average, but the blind participants did not. A follow-up experiment demonstrated that visual memory was the primary influence causing the size overestimations. We conclude that blind individuals are more accurate than sighted individuals in representing the size of familiar objects because they rely on manual representations, which are less influenced by visual experience than are visual memory representations.