bluuebunny/crossref_metadata_2025 huggingface dataset:
A portable earth‐drill system for permafrost studies
Authors: Calmels Fabrice , Gagnon Olivier , Allard Michel
Published: August 2005

This technical note presents a light drill specially designed for coring in permafrost. The drill was improved over several years at Université Laval's Centre d'études nordiques. More efficient than the conventional CRREL coring kit, the equipment allows total‐length recovery of cores 10 cm in diameter nearly without alteration, and works in most kinds of frozen soils. Drilling is possible to 7 m using a two to three‐person operating crew. Copyright © 2005 John Wiley & Sons, Ltd.
Temperature distribution in dc Joule‐heated amorphous ribbons
Authors: Aştefănoaei I. , Radu D. , Chiriac H.
Published: August 2005

The model presented here allows us to find the temperature distribution in an amorphous ribbon through which a dc current passes. With this end in view, we have taken into account the most important dc Joule heating effects: conduction, convection and radiative heat losses as well as the structural changes that appear in the crystallization process. In the domain situated above the temperature that corresponds to the onset of the crystallization process, we have studied the thermal behavior of the sample and we have analyzed the kinetics of the crystallization phenomenon for both the isothermal process and for the nonisothermal crystallization process (based on the Johnson–Mehl–Avrami equation). The computed temperature values (corresponding to amorphous phase) are experimentally verified through magnetic measurements using a fluxmeter method (performed on amorphous ribbons with known Curie temperature), while those corresponding to the crystallization process are experimentally verified using differential scanning calorimetry analysis and X‐ray difraction. We conclude that the dc Joule heating of ribbon is accurately described by this model, the analytically and numerically obtained results being in good agreement with experimental data. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vagus nerve stimulation suppresses pain but has limited effects on neurogenic inflammation in humans
Authors: Kirchner Annette , Stefan Hermann , Bastian Katrin , Birklein Frank
Published: August 2005

Left vagus nerve stimulation reduces pain perception in humans. In animal studies it has been shown that beyond the inhibitory effect, which the vagus nerve exerts via its widespread central connections, there might be also a peripheral effect on nociceptors. In humans, the exact mechanisms of VNS‐mediated analgesia are still unclear.

To test whether VNS also affects activation of primary nociceptive afferents in humans, we investigated 11 patients before and after implantation of a vagus nerve stimulator by using tonic pressure as pain stimulus. Vasodilator axon reflexes (“neurogenic” inflammation) were quantified by laser‐Doppler‐imaging and served as surrogates for primary afferent activation. Pain was measured on a visual analogue scale (VAS). The squeezing experiment was performed three times at 15 min intervals in each session. As controls 9 healthy age‐ and gender‐matched subjects were studied.

As shown in our previous study, VNS significantly reduces pain to tonic pressure. Likewise, there was a moderate reduction of the blood flow within the area of the axon reflex, which indicates a possible but limited inhibitory effect of VNS on peripheral nociceptors.

Our data suggests that VNS might affect peripheral nociceptor function in humans. Since VNS has been shown to be more effective in experimental procedures in which pain magnitude is amplified by central processing, further studies are warranted to elucidate whether the central or peripheral effect is most important for VNS‐mediated analgesia.
Enhancement and inhibition of DNA transcriptional activity by spermine: A marked difference between linear and circular templates
Authors: Luckel François , Kubo Koji , Tsumoto Kanta , Yoshikawa Kenichi
Published: August 2005

We compared the transcriptional activities of the circular and linear forms of short (4 kbp) and giant (106 kbp) DNA molecules in the presence of a polyamine, spermine (4+). With an increase in the spermine concentration, transcriptional activity was enhanced, followed by an inhibitory effect, and complete inhibition was observed in the sole case of long, linear templates. A difference between the transcriptional properties of circular and linear conformations is found for giant DNA molecules. These results are discussed in relation to DNA conformational transitions.
Angiotensin II induces tyrosine nitration and activation of ERK1/2 in vascular smooth muscle cells
Authors: Pinzar Elena , Wang Tianyi , Garrido Maria R. , Xu Wei , Levy Patrick , Bottari Serge P.
Published: August 2005

Angiotensin II (Ang II) induces a prominent and sustained nitration and activation of ERK1/2 in rat vascular smooth muscle cells, both mediated via AT1 receptor. Nitration and activation was also shown for recombinant non‐activated extracellular signal‐regulated kinase (ERK) and MEK. Nitration and phosphorylation of ERK1/2 by Ang II was significantly inhibited by NAD(P)H inhibitors and scavengers of oxygen and nitrogen reactive species and completely blocked by a selective inducible nitric‐oxide synthase inhibitor. MEK inhibitor U0126 did not affect ERK nitration but completely blocked activation. These data indicate that Ang II nitrates and activates ERK1/2 via a reactive species‐sensitive pathway.
Identification of VaD and AD prodromes: The Cache County Study
Authors: Hayden K.M. , Warren L.H. , Pieper C.F. , Østbye T. , Tschanz J.T. , Norton M.C. , Breitner J.C.S. , Welsh‐Bohmer K.A.
Published: August 2005

Background

It is unclear whether vascular dementia (VaD) has a cognitive prodrome, akin to the mild cognitive impairment (MCI) prodrome to Alzheimer's dementia (AD). To evaluate whether VaD has a cognitive prodrome, and if it can be differentiated from prodromal AD, we examined neuropsychological test performance of participants in a nested case‐control study within a population‐based cohort aged 65 or older.

Methods

Participants (n = 485) were identified from the Cache County Study, a large population‐based study of aging and dementia. After an average of 3 years of follow‐up, a total of 62 incident dementia cases were identified (14 VaD, 48 AD). We identified a number of neuropsychological tests (executive and memory) that discriminated between diagnosed VaD and AD cases. Multivariate analyses sought to differentiate between these same groups 3 years before clinical diagnosis.

Results

The Consortium to Establish a Registry for Alzheimer's Disease Word List Recognition Test correct recognition of foils (mean difference, 1.25; 95% confidence interval [CI], 0.42 to 2.07; p < 0.01), Logical Memory I (mean difference, 7.16; 95% CI, 0.78 to 13.55, p < 0.05), Logical Memory II delayed recall (mean difference, 8.67; 95% CI, 1.59 to 15.74, p < 0.05), and percent savings (mean difference, 51.07; 95% CI, 32.58 to 69.56, p < 0.0001) differentiated VaD from AD cases after adjustment for age, sex, education, and dementia severity. Three years before dementia diagnosis, word list recognition (“no” responses mean difference, 1.40; 95% CI, 0.64 to 2.17; p < 0.001, and “yes” responses mean difference, –1.14; 95% CI, –2.14 to –0.13; p < 0.03) discriminated between prodromal VaD and AD.

Conclusion

These results suggest that VaD has a prodromal syndrome, the cognitive features of which are distinguishable from the cognitive prodrome of AD.
Alzheimer's research: Can it help save our nation's entitlement programs?
Authors: McConnell Stephen , Riggs Judith
Published: August 2005

Demographics and government budget policies are on a collision course. The aging of the massive baby boom generation is threatening the future solvency of the nation's entitlement programs. The budget‐driven response by policy makers is to cut entitlements and reduce spending on discretionary programs, such as funding for research supported by the National Institutes of Health (NIH). Sadly, this response is likely to exacerbate the problem by limiting program changes that can better respond to the aging population and draining resources away from scientific inquiry that can help alleviate future fiscal burdens. A more viable solution would be to reform health and long‐term care programs to better address the chronic care needs of the aging population and to fully fund science that can delay onset and slow progression of life‐threatening diseases like Alzheimer's.
Treatment of hypertension and prevention of dementia
Authors: Hanon Olivier , Forette Françoise
Published: August 2005

Because of the aging population, the frequency of dementia will dramatically increase in the coming years. Prevention of cognitive disorders and dementia has become a major public health challenge. High blood pressure is a major risk factor for cerebrovascular diseases and is also correlated closely with cognitive decline and dementia. Several epidemiologic studies have found that cognitive functions are often inversely proportional to blood pressure values measured 15 or 20 years previously. Moreover, the use of antihypertensive drugs has been shown to help prevent cognitive decline, opening the way to the prevention of dementia (vascular or Alzheimer's type). These results indicate that incidence of dementia should constitute a major outcome of future trials comparing different classes of antihypertensive drugs.
Mars Global Surveyor observations of the Halloween 2003 solar superstorm's encounter with Mars
Authors: Crider Dana H. , Espley Jared , Brain David A. , Mitchell David L. , Connerney John E. P. , Acuña Mario H.
Published: August 2005

Like at Earth, disturbances from solar storms affect the space environment as they encounter Mars. The effects of the 28 October 2003 solar superstorm were among the greatest observed by the Mars Global Surveyor spacecraft at Mars to date. The disturbance, defined by an increase in incident solar wind pressure, encountered Mars on 30 October 2003 and persisted for 43 hours. We present the effects of the passage of this high‐pressure disturbance and compare the modified Martian space environment to more quiescent times. We find that the horizontal component of magnetic field is increased on the dayside. In addition, the solar wind interaction region is compressed during the disturbance. The solar wind flow has access to lower altitudes than typical, which likely increases mass loss from the Martian atmosphere. Regions of opened magnetic field lines can be closed at 400 km due to the compression of minimagnetospheres, thus altering locations where ionospheric plasma is protected from solar wind scavenging at 400 km altitude.
Climatological baroclinic forcing of the barotropic flow in the East Greenland Current in Fram Strait
Authors: Schlichtholz Pawel
Published: August 2005

Baroclinic forcing of the barotropic flow in the East Greenland Current in Fram Strait (EGCFS) is studied using theoretical analysis and climatological data. First, the validity of the arrested topographic wave (ATW) vorticity balance is reexamined. Then, a distribution of the net (depth‐averaged) relative geostrophic flow and the associated along‐isobath variations of the bottom density are estimated from the Polar Science Center Hydrographic Climatology (Seattle, Washington, United States). The effect of the along‐isobath bottom density variations is referred to as JEBARb in order to distinguish it from the famous JEBAR (joint effect of baroclinicity and relief), which involves depth‐integrated density variations. It is shown that the JEBARb is able to maintain a significant bottom geostrophic flow in the climatological EGCFS. Estimates of the JEBARb at 79°N correspond to an increase of the magnitude of the flow by ∼3 cm s−1 over a distance of 200 km along the continental slope. An analytical solution for the flow that is driven by a constant JEBARb term and satisfies the ATW vorticity balance is then obtained in a domain bounded by two parallel isobaths. Finally, the JEBARb is related to the JEBAR. It is shown that while the JEBARb maintains the curl of the Coriolis force associated with the bottom geostrophic flow, the JEBAR maintains the curl of the net Coriolis force associated with the absolute geostrophic flow. In the climatological EGCFS over the continental slope, the JEBAR is nearly equal to the JEBARb.
Secondary Hawaiian volcanism formed by flexural arch decompression
Authors: Bianco Todd Anthony , Ito Garrett , Becker Janet M. , Garcia Michael O.
Published: August 2005

This paper explains two forms of secondary Hawaiian volcanism (rejuvenated onshore and Hawaiian Arch offshore) as a direct consequence of lithospheric flexural uplift that surrounds growing shield volcanoes. This uplift decompresses the underlying asthenosphere, which is assumed to be chemically and isotopically heterogeneous, near its solidus, and derived from the Hawaiian mantle plume. Lithospheric uplift is modeled as the axisymmetric response of an elastic plate to a (volcanic) point load that grows linearly in time. To model flow in the asthenosphere, the rate of flexure of the lithosphere is taken as the upper boundary condition on an isoviscous, incompressible, fluid half‐space. This model successfully explains the majority of spatial gaps between secondary and active shield volcanism due to the flexing of a lithospheric plate with an effective elastic thickness of 25–35 km. Second, this work demonstrates that the flexural model can produce realistic magmatic fluxes if magma is focused toward individual eruption sites from the mantle over an area two to ten times the eruption area. Next, this model addresses the isotopic distinction between secondary and shield lavas. In this model, the same heterogeneous mantle plume feeds the secondary and shield lavas, but the compositional components are sampled by melting at rates that differ between the two settings. Flexural decompression mostly melts the component that begins melting shallowest, which we assume to be depleted in incompatible elements with relatively low 87Sr/86Sr and high 143Nd/144Nd. Melting in the center of a mantle plume is assumed to generate shield volcanism and is predicted to mostly melt components that begin melting deepest, which we assume to be enriched in incompatible elements with higher 87Sr/86Sr and lower 143Nd/144Nd. Thus the models successfully predict the observed mean 87Sr/86Sr and 143Nd/144Nd isotopic compositions of secondary and shield lavas to arise out of the melting process alone. The fourth feature addressed is that secondary lavas are alkalic, having formed from relatively low extents of partial melting, and shield lavas are dominantly tholeiitic, consistent with more extensive partial melting. Indeed, models predict lower mean extent of melting for secondary lavas compared to shield lavas if the source material, which is mostly peridotite, contains at least some pyroxenite. Results show that model predictions are consistent with the geochemical constraints for a range of reasonable starting mantle compositions, lithospheric thicknesses, and plume temperatures.
Potential regional climate change and implications to U.S. air quality
Authors: Leung L. Ruby , Gustafson William I.
Published: August 2005

Regional climate change scenarios were generated by dynamical downscaling to assess the potential effects of climate change on U.S. air quality. Comparing the climate simulation for 2045–2055 based on the IPCC A1B scenario with the control simulation of 1995–2005, large atmospheric changes that could affect air quality were found in several regions. Analyses were based on changes in surface air temperature and downward solar radiation, precipitation frequency, stagnation events, and ventilation. Changes in the Midwest and Texas during summer are of opposite sign, suggesting negative impacts on air quality in Texas and small positive or no impact in the Midwest. During fall, large warming, increased solar radiation, reduced rainfall frequency, increased stagnation occurrence, and reduced ventilation in the western U.S. all suggest negative impacts on regional air quality. These changes are related to an anticyclonic pattern in the 500 hPa height change that is also found in other GCM projections.
Abrupt climate change and variability in the past four millennia of the southern Vancouver Island, Canada
Authors: Zhang Qi‐Bin , Hebda Richard J.
Published: August 2005

The identification of past climatic extremes and norms is important for a better understanding of the climate systems and the way they change. Here we present an almost continuous tree‐ring and climate record from Vancouver Island, Canada for the last four millennia from Douglas‐fir trees (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) that are sensitive to precipitation variation. Spring droughts more severe than that of the mid‐1920s occurred in the late 1840s, mid‐1460s AD, and ∼ mid‐1860s BC. A remarkable climatic anomaly occurred in ∼ the 19th century BC during which strong pentadecadal oscillation prevailed and radial growth decreased by 71% in four years. This event could have been the final stage in the process of climatic and environmental transition beginning 2–3 centuries earlier that led to major cultural transformation in regions sensitive to climate change.
Magnetospheric substorms are strongly modulated by interplanetary high‐speed streams
Authors: Tanskanen E. I. , Slavin J. A. , Tanskanen A. J. , Viljanen A. , Pulkkinen T. I. , Koskinen H. E. J. , Pulkkinen A. , Eastwood J.
Published: August 2005

The occurrence of substorms was examined over a complete 11‐year solar cycle, identifying over 5000 substorms. It was found that high‐speed streams strongly modulate the substorm occurrence rate, peak amplitude and ionospheric dissipation in the form of Joule heating and auroral electron precipitation. Substorms occurring during the years of frequent interplanetary high‐speed streams (1994 and 2003) are 32% more intense, on average, and transfer twice as much magnetic energy to the auroral ionosphere as the substorms occurring during the years of few or no high‐speed streams (1993, 1995–2002). To characterize and to predict the substorm activity we form a new measure, the substorm activity parameter Rsu, which we expect to become a powerful tool in analyzing the near‐Earth space climate.
Reexamination of the coronal index of solar activity
Authors: Rybanský M. , Rušin V. , Minarovjech M. , Klocok L. , Cliver E. W.
Published: August 2005

The coronal index (CI) of solar activity is the irradiance of the Sun as a star in the coronal green line (Fe XIV, 530.3 nm or 5303 Å). It is derived from ground‐based observations of the green corona made by the network of coronal stations (currently Kislovodsk, Lomnický Štít, Norikura, and Sacramento Peak). The CI was introduced by Rybanský (1975) to facilitate comparison of ground‐based green line measurements with satellite‐based extreme ultraviolet and soft X‐ray observations. The CI since 1965 is based on the Lomnický Štít photometric scale; the CI was extended to earlier years by Rybanský et al. (1994) based on cross‐calibrations of Lomnický Štít data with measurements made at Pic du Midi and Arosa. The resultant 1939–1992 CI had the interesting property that its value at the peak of the 11‐year cycle increased more or less monotonically from cycle 18 through cycle 22 even though the peak sunspot number of cycle 20 exhibited a significant local minimum between that of cycles 19 and 21. Rušin and Rybanský (2002) recently showed that the green line intensity and photospheric magnetic field strength were highly correlated from 1976 to 1999. Since the photospheric magnetic field strength is highly correlated with sunspot number, the lack of close correspondence between the sunspot number and the CI from 1939 to 2002 is puzzling. Here we show that the CI and sunspot number are highly correlated only after 1965, calling the previously‐computed coronal index for earlier years (1939–1965) into question. We can use the correlation between the CI and sunspot number (also the 2800 MHz radio flux and the cosmic ray intensity) to recompute daily values of the CI for years before 1966. In fact, this method can be used to obtain CI values as far back as we have reliable sunspot observations (∼1850). The net result of this exercise is a CI that closely tracks the sunspot number at all times. We can use the sunspot‐CI relationship (for 1966–2002) to identify which coronal stations can be used as a basis for the homogeneous coronal data set (HDS) before 1966. Thus we adopt the photometric scale of the following observatories for the indicated times: Norikura (1951–1954; the Norikura photometric scale was also used from 1939 to 1954); Pic du Midi (1955–1959); Kislovodsk (1960–1965). Finally, we revised the post‐1965 HDS and made several small corrections and now include data from Kislovodsk, Norikura, and Sacramento Peak to fill gaps at Lomnický Štít.
On the relationship between surface and basal properties on glaciers, ice sheets, and ice streams
Authors: Raymond M. J. , Gudmundsson G. H.
Published: August 2005

The influence of basal disturbances on the steady state surface topography and on surface velocities of glaciers and ice sheets is investigated numerically. This is done for finite amplitude basal perturbations in both bed topography and basal slipperiness using a nonlinear ice rheology and a nonlinear sliding law. The effects of varying the exponent n in Glen's flow law on transfer characteristics are mainly quantitative and do not affect qualitative aspects of the transfer amplitudes and phase shifts, such as the number of maxima and inflection points when plotted as functions of wavelength. In particular, the well‐known maximum in bed‐to‐surface transfer amplitude for a Newtonian medium at sufficiently high slip ratios (ratio between mean sliding velocity and mean ice deformational velocity) also forms for n > 1. Transfer amplitudes generally become smaller with increasing n for wavelengths less than about 3 times the mean ice thickness (h). For larger wavelengths the situation is reversed and transfer amplitudes increase with n. For active ice streams, characterized by high basal slipperiness, low surface slopes (<0.5°), and n = 3, topographic transfer amplitudes are generally large (>0.5) and fairly constant for all wavelengths longer than about 3–5h. With increasing n and decreasing surface slope the lower limit of wavelengths over which horizontal stress gradients can be ignored increases markedly. Perturbation solutions for Newtonian medium are found to give an accurate description of the transfer characteristics for bedrock amplitudes up to 50% ice thickness and for fractional amplitudes of slipperiness perturbations up to 0.5.
Experimental study and modeling of polydimethylsiloxane peristaltic micropumps
Authors: Goulpeau Jacques , Trouchet Daniel , Ajdari Armand , Tabeling Patrick
Published: August 2005

We present here an experimental study of three-valve peristaltic micropumps fabricated using polydimethylsiloxane multilayer soft lithography, along with a simple model representing their behavior. Variations of the generated flow rate with peristaltic cycle frequencies, design parameters, actuation pressures, and fluid viscosities are analyzed experimentally for a set of ten micropumps. The largest flow rates are obtained for particular “optimal” basic parameters (actuation pressures and cycle frequencies) that depend on design features. A single-valve model, based on nonlinear equivalent electrical circuits, is numerically and analytically solved in relevant cases, leading to qualitative and quantitative agreements with experiments. From this theoretical study, useful predictive rules are deduced for pump design. The maximum flow rate we could achieve is 7.5μL∕min, one order-of-magnitude improvement compared to the highest level reported for this particular type of micropump. The design of the actuation system—including both internal and external micropump elements—was found crucial to achieving high flow rates.
Parametric instability of a driven ion-acoustic wave
Authors: Pesme D. , Riconda C. , Tikhonchuk V. T.
Published: August 2005

The stability of a driven coherent ion-acoustic wave (IAW) with regard to its decay into longer wavelengths is investigated. The effects of harmonic generation and wave dispersion are taken into account. The driver frequency and wave number do not necessarily satisfy the linear ion-acoustic wave dispersion relation, allowing a frequency mismatch between the driver frequency and the plasma linear-response frequency. The stability analysis is generally shown to involve a seven wave coupling in which the fundamental and the second-harmonic components of the equilibrium IAW couple to a low-frequency daughter wave and to their Stokes and anti-Stokes satellites. The general dispersion relation corresponding to this seven wave coupling is derived and solved numerically in three-dimensional geometry. A variety of branches of instabilities is found to appear. In order to classify these branches, an approximate dispersion relation is derived, corresponding to the Korteweg–de-Vries limit for the plasma low-frequency nonlinear behavior. This approximate dispersion relation makes it possible to obtain approximate expressions for the growth rate of each branch. The occurrence of each type of instability is discussed as a function of the sign and size of the frequency mismatch. The special case of one-dimensional geometry is also considered, making it possible to investigate the results of one-dimensional numerical simulations.
Resonance contributions to anti-Stokes/Stokes ratios under surface enhanced Raman scattering conditions
Authors: Maher R. C. , Hou J. , Cohen L. F. , Le Ru E. C. , Hadfield J. M. , Harvey J. E. , Etchegoin P. G. , Liu F. M. , Green M. , Brown R. J. C. , Milton M. J. T.
Published: August 2005

Anti-Stokes/Stokes asymmetries under surface enhanced Raman scattering (SERS) conditions are studied for a wide variety of SERS-active media and different analytes. Evidence is provided for the existence of underlying resonances that create these asymmetries. We show here that these resonances are associated with the electromagnetic coupling between the analyte (probe) and the metal. The work demonstrates the use of the anti-Stokes/Stokes ratio as a tool to understand the hierarchy of resonances in the SERS problem, which is essential for quantification purposes.
Laser ablation of silicon in neon gas: Study of excitation mechanism of neon neutrals by ablated silicon ions
Authors: Saeki Morihisa , Hirata Kohichi , Sakka Tetsuo , Ohba Hironori , Yokoyama Atsushi
Published: August 2005

The excitation mechanism of buffer gas in the laser-ablation process was investigated by time- and space-resolved emission spectroscopies. A silicon disk was ablated in neon gas at a pressure of 1 torr by the fundamental beam output of a Nd: yttrium aluminum garnet laser (1064 nm). The time-resolved emission spectra showed the generation of excited silicon ions Sin+*(n=1−3) and excited neon neutrals Ne* to the 2p1 level immediately after laser irradiation. Excitation of Ne to the 2pn(n=2−10) levels was delayed by 150 ns. The temporal evolutions of the space-resolved emission from Ne* indicated excitation by fast (<100ns) and/or slow (<300ns) processes. The slow process contributed to all 2pn levels, while the fast process was observed only in excitation to the 2p1 level. This means that the fast process involves level-selective excitation. Based on temporal evolutions, the energy levels, and the collision cross sections of Ne and Sin+, we assigned the fast and slow processes to excitations by electronic-to-electronic energy transfer from Si2+* and translational-to-electronic energy transfer from Si+, respectively.
Quasi-Classical Trajectory study of Si+O2→SiO+O reaction
Authors: Dayou F. , Tchang-Brillet W.-Ü. L. , Monnerville M.
Published: August 2005

Quasi-classical trajectory calculations for the Si(P3)+O2(XΣg−3)→SiO(XΣ+1)+O(D1) reaction have been carried out using the analytical ground A′1 potential energy surface (PES) recently reported by Dayou and Spielfiedel [J. Chem. Phys. 119, 4237 (2003)]. The reaction has been studied for a wide range of collision energies (0.005–0.6eV) with O2 in its ground rovibrational state. The barrierless PES leads to a decrease of the total reaction cross section with increasing collision energy. It has been brought to evidence that the reaction proceeds through different reaction mechanisms whose contributions to reactivity are highly dependent on the collision energy range. At low collision energy an abstraction mechanism occurs involving the collinear SiOO potential well. The associated short-lived intermediate complex leads to an inverted vibrational distribution peaked at v′=3 and low rotational excitation of SiO(v′,j′) with a preferentially backward scattering. At higher energies the reaction proceeds mainly through an insertion mechanism involving the bent and linear OSiO deep potential wells and associated long-lived intermediate complexes, giving rise to nearly statistical energy disposals into the product modes and a forward-backward symmetry of the differential cross section.
Quasi-monoenergetic electron beam generation during laser pulse interaction with very low density plasmas
Authors: Yamazaki A. , Kotaki H. , Daito I. , Kando M. , Bulanov S. V. , Esirkepov T. Zh. , Kondo S. , Kanazawa S. , Homma T. , Nakajima K. , Oishi Y. , Nayuki T. , Fujii T. , Nemoto K.
Published: August 2005

The results of experiments are presented for the single laser pulse interaction with a very low density gas target, under the conditions when the generated wake wave is below the wave-breaking threshold and the laser pulse power is lower than the critical power for relativistic self-focusing. A quasi-monoenergetic electron beam is found to be stably generated for various laser pulse intensity values by controlling the acceleration length. The results of two-dimensional particle-in-cell simulations show that for the electron acceleration an additional mechanism of electron injection into the acceleration phase is required. It is demonstrated that the longitudinal inhomogeneity of the plasma density leads to the electron injection.
Propagation properties of planar Bragg waveguides studied by an analytical Bloch-mode method
Authors: Sang Hong-Yi , Li Zhi-Yuan , Gu Ben-Yuan
Published: August 2005

We use an analytic Bloch-mode approach to investigate one-dimensional planar Bragg waveguides (PBWGs) with an air- or a glass-core layer sandwiched within two symmetric Bragg gratings formed by alternate arrays of air and glass layers. The calculation results show that there exist simultaneously two kinds of guided modes as the gap-guided modes resulting from the photonic band-gap effect and the index-guided modes formed by the total internal reflection effect. We calculate the electromagnetic (EM)-field distributions of these guided modes with different parallel wave vectors and find remarkably different EM-field profiles between the index-guided modes and the gap-guided modes. In order to explore the propagation properties of the PBWGs, we analyze the group velocity and the group-velocity dispersion of different types of guided modes. The results show that the guided mode properties are significantly influenced by the core material as well as the cladding structure. The analytic Bloch-mode approach can help to investigate and design the PBWGs in a simple, efficient, and accurate manner.
Formation of GaAs∕AlGaAs and InGaAs∕GaAs nanorings by droplet molecular-beam epitaxy
Authors: Gong Z. , Niu Z. C. , Huang S. S. , Fang Z. D. , Sun B. Q. , Xia J. B.
Published: August 2005

GaAs ∕ AlGaAs lattice-matched nanorings are formed on GaAs (100) substrates by droplet epitaxy. The crucial step in the formation of nanorings is annealing Ga droplets under As flux for proper time. The observed morphologic evolution of Ga droplets during annealing does not support the hypothesis that As atoms preferentially react with Ga around the periphery of the droplets, but somehow relates to a dewetting process similar to that of unstable films. Photoluminescene (PL) test results confirm the quantum-confinement effect of these GaAs nanorings. Using similar methods, we have fabricated InGaAs∕GaAs lattice-mismatched rings.
Effect of nisin on ruminal methane production and nitrate/nitrite reduction in vitro
Authors: Sar C. , Mwenya B. , Pen B. , Morikawa R. , Takaura K. , Kobayashi T. , Takahashi J.
Published: August 2005

The suppressing effects of different concentrations of nitrate (0, 5, 10, 15, and 20 mm) or nisin (0, 5, 10, 15, 20, and 30 μmol/L) on in vitro methane production were examined with mixed rumen microbes using the in vitro continuous incubation system. The effects of different concentrations of nisin (10, 20, and 30 μmol/L) on in vitro nitrate/nitrite reduction were examined for methane suppression without any nitrate toxicity. The culture mixture consisted of 400 mL of strained rumen fluid from 2 non-lactating Holstein cows fed a diet of oaten hay, alfalfa hay cube, and concentrates (35 : 35 : 30) at maintenance level, and 400 mL of autoclaved buffer solution. Methane production was decreased with increasing levels of nitrate. As the concentration of nisin increased from 5 to 30 μmol/L, methane production was decreased by 14–40%. A decrease in acetate to propionate ratio and increase in total volatile fatty acids were observed as the concentration of nisin increased. Toxic nitrite accumulation was unaffected by increasing levels of nisin. In conclusion, nisin improved some of the parameters of ruminal fermentation and inhibited methane production, but did not decrease nitrate toxicity when nitrate was used to inhibit methane production.
Effects of spray-dried colostrum and plasmas on the performance and gut morphology of broiler chickens
Authors: King M. R. , Ravindran V. , Morel P. C. H. , Thomas D. V. , Birtles M. J. , Pluske J. R.
Published: August 2005

The influence of feeding with starter diets containing spray-dried bovine colostrum (SBC), spray-dried bovine plasma (SBP), or spray-dried porcine plasma (SPP) on the growth performance and gut morphology of broiler chickens was investigated. The crude protein, lysine, and methionine plus cystine contents (g/kg as received) of SBC, SBP, and SPP were determined to be 766, 736, and 684; 58, 61, and 55; and 27, 28, and 24, respectively. The 3 test proteins were incorporated into a maize–soybean meal diet at a level of 50 g/kg and fed to 6 replicates of 8 male broiler chicks from 1 to 14 days of age. On Day 14, the experimental diets were replaced with a common grower-finisher diet, which was offered until Day 35. Dietary treatments had no effect (P > 0.05) on the weight gain or feed intake of birds during the first 14 days. However, feed/gain of birds fed the SBC diet was lower (P < 0.05) than of those fed the control diet. A trend for a reduction in feed/gain (P = 0.06) was observed in SBP and SPP diets. Dietary treatments had no effect (P > 0.05) on performance during Days 14–35 or Days 1–35. Villus height was increased by 5.7% (P < 0.05) and 4.6% (P = 0.05) in birds fed the SPP and SBP diets, respectively, compared with those fed the control diet. Crypt depth was 6% greater (P < 0.05) in birds fed the SPP diet and tended (P = 0.08) to be greater in birds fed the SBC diet, compared with birds fed the control. The ratio of villus height to crypt depth tended (P = 0.06) to be lower in birds offered the SBC diet compared with the control. Crypt goblet cell density was reduced (P < 0.05) by 13.9% in birds fed the SBC diet, compared with control birds. These results suggest that feeding with diets containing the SBC, SBP, and SPP during 1–14 days of age has some beneficial effects on broiler chickens. Further studies are needed to evaluate these products in less sanitary environments, which may increase the positive responses.
The importance of accounting for maternal genetic effects in Australian fine-wool Merino breeding
Authors: Fozi M. Asadi , Van der Werf J. H. J. , Swan A. A.
Published: August 2005

(Co) variances for greasy fleece weight (GFW), clean fleece weight (CFW), mean fibre diameter (MFD), staple strength (SS), coefficient of variation of fibre diameter (CVFD), birthweight (BW), weaning weight (WW), and yearling weight (YW) were estimated for 5108 Australian Merino sheep from the CSIRO Fine Wool Project, born between 1990 and 1994. Covariances between these traits and number of lambs weaned per ewe joined (NLW) were also estimated. Significant maternal genetic effects were found for GFW, CFW, BW, WW, and YW. Estimates of heritability were biased upwardly when maternal effects were ignored. The maternal heritability estimates for GFW, CFW, BW, WW, and YW were 0.17, 0.15, 0.38, 0.28, and 0.13, respectively. Maternal effects were not important for MFD, CVFD, SS, and NLW. Direct-maternal genetic correlations within each fleece weight and bodyweight trait were estimated to be moderately negative (–0.26 to –0.48). The effect of ignoring maternal genetic effect was explored using selection index theory. Accounting for the maternal effects in both the selection criteria and breeding objective increased the overall response by 14.3%, 4.8%, 2.6%, 1.4%, and 0.0% in 3, 6, 12, 20 and 30% micron premium scenarios, respectively, compared with when the maternal effects were only included in breeding objective. Complete ignorance of the maternal effects led to overestimation in overall response of 2.8–35.7% for different micron premium scenarios in contrast to when the maternal effects were ignored in the selection index weight, but were included in the breeding objective. The results indicate that the maternal genetic effects of fleece weight and bodyweight should be considered in Merino breeding programs.
Further studies on Carrot virus Y: hosts, symptomatology, search for resistance, and tests for seed transmissibility
Authors: Jones R. A. C. , Smith L. J. , Gajda B. E. , Smith T. N. , Latham L. J.
Published: August 2005

Carrot virus Y (CarVY) was studied to provide information on its host range and symptoms, identify any alternative natural hosts and sources of host resistance in carrot germplasm, and determine whether it is seed-borne. Twenty-two species belonging to the Apiaceae were inoculated with CarVY by viruliferous aphids in the glasshouse. Systemic infection with CarVY developed in carrot itself, 4 other Daucus species, 5 herbs, 1 naturalised weed, and 2 Australian native plants. When 7 of these host species were exposed to infection in the field, all became infected systemically. In both glasshouse and field, the types of symptoms that developed in infected plants and their severity varied widely from host to host. Following inoculation with infective sap, the virus was detected in inoculated leaves of 1 additional species in the Apiacaeae, and 2 species of Chenopodiaceae. A field survey did not reveal any alternative hosts likely to be important as CarVY infection reservoirs. When 34 accessions of wild carrot germplasm and 16 of other Daucus spp. were inoculated with infective aphids, symptom severity varied widely among accessions but no source of extreme resistance to CarVY was found. Tests on seedlings grown from seed collected from individual infected plants or field plantings (most with CarVY incidences of >92%) of cultivated carrot (34 135 seeds), wild carrot (20 978 seeds), Anethum graveolens (22 921 seeds), and 3 other host species (3304 seeds) did not detect any seed transmission of CarVY. The implications of these results for control of the virus in carrot crops, minimising the losses it causes, and avoiding its introduction to new locations are discussed.
Crystal structures and mutational analysis of amFP486, a cyan fluorescent protein from Anemonia majano
Authors: Henderson J. Nathan , Remington S. James
Published: August 2005

Fluorescent proteins isolated from coral reef organisms can be roughly grouped into four color classes by emission, cyan, green, yellow, and red. To gain insight into the structural basis for cyan emission, the crystal structure of amFP486 (

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= 486 nm) was determined by molecular replacement, and the model was refined at 1.65-Å resolution. The electron density map reveals a chromophore formed from the tripeptide sequence –K–Y–G– that is indistinguishable from that of GFP (

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= 509 nm). However, the chromophore environment closely parallels those of the yellow- and red-shifted homologs zFP538, DsRed, and eqFP611. Mutagenesis was performed for Glu-150, Ala-165, His-199, and Glu-217, which are immediately adjacent to the chromophore. His-199 and Ala-165 are key side chains responsible for the blue shift, presumably by localizing chromophore charge density on the phenolate moiety. Furthermore, in the H199T mutant the fluorescence quantum yield is reduced by a factor of ≈110. The crystal structures of H199T (

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= 515 nm) and E150Q (

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= 506 nm) were determined. Remarkably, the H199T structure reveals that the stacking interaction of His-199 with the chromophore also controls the fluorescence efficiency, because the chromophore is statistically distributed in a 1:1 ratio between cis (fluorescent) and trans (nonfluorescent) conformations.
Cyp12a4
confers lufenuron resistance in a natural population of
Drosophila melanogaster
Authors: Bogwitz Michael R. , Chung Henry , Magoc Lorin , Rigby Sheena , Wong Wayn , O'Keefe Melanie , McKenzie John A. , Batterham Philip , Daborn Phillip J.
Published: August 2005

Lufenuron is an insect growth regulator insecticide mainly used for the control of the cat flea. To understand mechanisms of resistance to lufenuron, we have characterized lufenuron resistance in a natural population of
Drosophila melanogaster
. In this study we have used precise genetic mapping to identify a mechanism of lufenuron resistance: the overexpression of the cytochrome P450 gene
Cyp12a4. Cyp12a4
is predicted to encode a mitochondrial cytochrome P450 enzyme. Expression of
Cyp12a4
in
D. melanogaster
third-instar larvae was detected in the midgut and Malpighian tubules of both lufenuron-resistant and wild-type strains. The level of
Cyp12a4
expression in the midgut is higher in the lufenuron-resistant strain than in wild-type strains. Driving the expression of
Cyp12a4
in the midgut and Malpighian tubules by using the GAL4/UAS gene expression system results in lufenuron resistance, but it does not result in resistance to three other insecticide classes. Transgenic expression of
Cyp12a4
in a ubiquitous expression pattern results in late embryonic lethality, suggesting that high-level ectopic expression of
Cyp12a4
is detrimental to development.
Kernel energy method: Application to insulin
Authors: Huang Lulu , Massa Lou , Karle Jerome
Published: August 2005

In two recent articles a method has been described for calculating the total energy of large molecules. The method is called the kernel energy method (KEM) and requires knowledge of the crystal structure of interest. Calculations are simplified by adopting the approximation that a full molecule could be represented by smaller kernels of atoms. The KEM was illustrated with peptides ranging in size from 4 to 19 amino acid residues, and was found to deliver accurate results. The use of the KEM does not depend upon a particular choice of basis functions and is applicable across quantum computational methods of differing levels of accuracy. These earlier investigations suggested that the KEM could be used to calculate the
ab initio
quantum mechanical energy of proteins. An application has been made with the protein insulin, composed of 51 aa. Accurate KEM Hartree–Fock energies are obtained for the separate A and B chains of insulin and for their composite structure in the full insulin molecule. A limited basis is used to make possible calculation of the full insulin molecule, which can be used as a standard of accuracy for the KEM calculation. The KEM result obtained is
E
KEM
= –21104.7656 a.u. It differs from a full molecule Hartree–Fock result by only 0.000002%. The solvent molecules can be treated effectively as a separate kernel. The KEM result for the fully solvated insulin molecule is
E
KEM
= –26275.4127 a.u., differing from the full molecule Hartree–Fock result by as little as 0.000023%.
Sustained suppression in congruency tasks
Authors: Notebaert Wim , Soetens Eric
Published: August 2005

In a list version of the Stroop task, Thomas (1977) observed that Stroop interference was smaller when the irrelevant word was repeated through parts of the list. MacLeod (1991) formulated the sustained-suppression hypothesis for this effect. It is assumed that the automatic response activation on the basis of the irrelevant word is selectively suppressed. In this paper this hypothesis is further investigated. In a serial Stroop task with short response–stimulus interval (RSI) we demonstrate that the Stroop effect disappears when the irrelevant word is repeated, whereas the Stroop effect is evident when the word changes. With a long RSI, there is no influence of the sequence of the irrelevant word. The same pattern of results is observed in a flanker task. The results are discussed in terms of the activation-suppression model (Ridderinkhof, 2002) and the sustained-suppression hypothesis.
A Retromerlike Complex Is a Novel Rab7 Effector That Is Involved in the Transport of the Virulence Factor Cysteine Protease in the Enteric Protozoan ParasiteEntamoeba histolytica
Authors: Nakada-Tsukui Kumiko , Saito-Nakano Yumiko , Ali Vahab , Nozaki Tomoyoshi
Published: August 2005

Vesicular trafficking plays an important role in a virulence mechanism of the enteric protozoan parasite Entamoeba histolytica as secreted and lysosomal cysteine protease (CP) contributes to both cytolysis of tissues and degradation of internalized host cells. Despite the primary importance of intracellular sorting in pathogenesis, the molecular mechanism of CP trafficking remains largely unknown. In this report we demonstrate that transport of CP is regulated through a specific interaction of Rab7A small GTPase (EhRab7A) with the retromerlike complex. The amoebic retromerlike complex composed of Vps26, Vps29, and Vps35 was identified as EhRab7A-binding proteins. The amoebic retromerlike complex specifically bound to GTP-EhRab7A, but not GDP-EhRab7A through the direct binding via the carboxy terminus of EhVps26. In erythrophagocytosis the retromerlike complex was recruited to prephagosomal vacuoles, the unique preparatory vacuole of digestive enzymes, and later to phagosomes. This dynamism was indistinguishable from that of EhRab7A, and consistent with the premise that the retromerlike complex is involved in the retrograde transport of putative hydrolase receptor(s) from preparatory vacuoles and phagosomes to the Golgi apparatus. EhRab7A overexpression caused enlargement of lysosomes and decrease of the cellular CP activity. The reduced CP activity was restored by the coexpression of EhVps26, implying that the EhRab7A-mediated transport of CP to phagosomes is regulated by the retromerlike complex.