bluuebunny/crossref_metadata_2025 huggingface dataset:
Imposex of Mauritia arabica on the south-eastern coast of China
Authors: Huang Changjiang , Zhu Shixi , Lin Junda , Dong Qiaoxiang
Published: October 2008

Imposex, the development of male sexual organs in female gastropods, is mainly induced by organotin compounds used as biocides in antifouling paints. As part of our continued efforts to report the occurrence of imposex gastropods along the coast of mainland China, this study investigates the imposex prevalence in Mauritia arabica (Mesogastropod: Cypraeidae). A total of 529 adults were collected from 11 sites in south-eastern China between March 2001 and June 2005. Of these, 303 were females and 226 were males. Imposex is classified into six stages representing the sequence from the initial appearance of the seminal groove or small penis (S1) to the point when this duct blocks the pallial oviduct and aborted egg capsules appear (S6). All six stages of imposex were found in M. arabica with three different types (a, b and c) of expression in stages 1 and 3, two types (a and b) in stage 2, and one type in stages 4, 5, and 6. Imposex development was also measured by various indices such as the vas deferens sequence index (VDS), female penis length (FPL), percentage of affected females (%I), the relative penis length (RPL), and relative penis size (RPS—the cubed form of RPL). Imposex individuals were found in all 11 sites with %I ranged from 26% to 100%. Excluding the data from site 3 (with only one female and one male), VDS scores ranged from 1.05 to 4.07, with an average of 2.86, and the RPL ranged from 0.9 to 56.8. High correlations were observed among VDS, FPL, %I, RPL, and the RPS. Our findings suggest that M. arabica is an ideal bioindicator for organotin pollution along the south-eastern coast of China, and can be used in conjunction with the rock shell, Thais clavigera, a well-established bioindicator of tributyltin and triphenyltin contamination. To our knowledge, this is the first detailed report of imposex in M. arabica.
AN EVAPORATION HEAT ENGINE AND CONDENSATION HEAT PUMP
Authors: BARTON N. G.
Published: October 2008

This paper presents a thermodynamic model for a heat engine based on evaporative cooling of unsaturated air at reduced pressure. Also analysed is a related heat pump based on condensation of water vapour in moist air at reduced pressure. These devices operate as two-stroke reciprocating engines, which are their simplest possible embodiments. The mathematical models for the two devices are based on conservation of mass for both air and water vapour, ideal gas laws, constant specific heats, and, as appropriate, either constant entropy processes or cooling/heating by evaporation/condensation. Both models take the form of coupled algebraic systems in six variables, which require numerical solution for certain stages of the cycle. The specific work output of the heat engine increases as the inlet air becomes hotter and as the expansion ratio of the engine increases. The engine provides evaporative cooling of air from inlet to outlet. The heat pump has a good coefficient of performance, which decreases as the expansion ratio increases. The heat pump also has the effect of drying the air from inlet to outlet, producing distilled water as a by-product.
A COMPUTATIONAL METHOD FOR SOLVING TWO-DIMENSIONAL LINEAR FREDHOLM INTEGRAL EQUATIONS OF THE SECOND KIND
Authors: TARI A. , SHAHMORAD S.
Published: October 2008

In this paper an expansion method, based on Legendre or any orthogonal polynomials, is developed to find numerical solutions of two-dimensional linear Fredholm integral equations. We estimate the error of the method, and present some numerical examples to demonstrate the accuracy of the method.
PERTURBATION THEORY FOR THE LU AND QR FACTORIZATIONS
Authors: WU CHI-YE , HUANG TING-ZHU
Published: October 2008

In this paper we derive perturbation theorems for the LU and QR factors. Moreover, bounds for κL(A)/κL′(A) and κU(A)/κ′U(A) are given for the LU factorization of a nonsingular matrix. By applying pivoting strategies in the LU factorization, estimates for κL(PAQ)/κL′(PAQ) and κU(PAQ)/κ′U(PAQ) are also obtained.
Pathologies or Progress? Evaluating the effects of Divided Government and Party Volatility
Authors: YAP O. FIONA , KIM YOUNGMI
Published: October 2008

A vast body of literature emphasizes that successful political development relies on stable and united political parties that underpin clear and responsive policymaking. By this perspective, divided government and party volatility represent pathologies that imperil political accountability and development. Indeed, studies contend that divided government – where different parties control the executive and legislative branches of government – lead to policy deadlock while party volatility – characterized by frequent party splits, solo switches, mergers, dissolutions or the establishment of new parties – confounds representation and accountability. Clearly, each on its own is seen as a considerable threat to political performance and democratic development; the confluence of the two points virtually to an inevitable political doom.
Executive–Legislature Divide and Party Volatility in Emergent Democracies: Lessons for Democratic Performance from Taiwan
Authors: YAP O. FIONA
Published: October 2008

Are new democracies with divided government and volatile parties politically ill fated? The literature suggests so, but cases of emergent democracies such as Taiwan and Brazil that face both conditions defy the prediction. This paper explains why: party volatility follows from pursuing distinct executive and legislature agendas under divided government; the political ambition that underlies these conditions sustains democratic and even political performance. We evaluate the argument through government spending in Taiwan. The results corroborate our expectations: they show more parties composing the legislature as government spending favors an executive agenda and neglects a legislative welfare-spending agenda. The findings make three contributions to the literature: first, they reveal a political divide between executive and legislature rather than ideological parties to undercut concerns regarding performance. Second, they demonstrate that the strategic use of government spending to institutionalize party development along an executive agenda fuels party fragmentation. Third, they show that legislators split, switch, or create alternative routes to office in reaction to strategic spending to underscore that ambition underlies party volatility and divided government.
Coalition Governments, Party Switching, and the Rise and Decline of Parties: Changing Japanese Party Politics since 1993
Authors: KATO JUNKO , KANNON YUTO
Published: October 2008

Since 1993, coalition governments have replaced the 38-year-long, one-party dominance of the Liberal Democratic Party (the LDP) in Japan. Except for one year, from 1993 to 1994, the LDP has remained a key party in successive governing coalitions, but the dynamics of party competition has been completely transformed since the period of the LDP's dominance. Although the LDP has survived to form a variety of coalitions ranging from a minority to an over-sized majority, since 1998 the Democratic Party of Japan (DPJ) has continued to counter the LDP governments. The transformation of party systems in Japan accompanies the party switching of legislators and the mergers, breakups, extinctions, and formations of parties. In this regard, the Japanese case provides an interesting example to show how parties attempt to change the dynamics of policy competition by switching and reorganizing. Parties also attempt to shift their policy positions to attract public support and to gain a competitive edge in government formation. Using expert survey data about the policy positions of parties, this study explicates the dynamics involved in the reorganization of parties and the formation of governments.
Changes in extreme, cold‐season synoptic precipitation events under global warming
Authors: Gutowski William J. , Willis Stephanie S. , Patton Jason C. , Schwedler Benjamin R. J. , Arritt Raymond W. , Takle Eugene S.
Published: October 2008

We analyze regional climate model (RCM) simulations of daily, spatially distributed extreme precipitation events, using co‐operative network observations and output from 10‐year RCM simulations of present and future‐scenario climates. We examine an Upper Mississippi River Basin region during October–March for daily amounts that exceed the 99.95th percentile and that occur simultaneously at several observation sites or model grid points. For the observations and each simulation, nearly all such extreme regional events occur when a slow moving, cut‐off‐low system develops over the Rockies and Great Plains and steadily pumps moisture into the Upper Mississippi region from the Gulf of Mexico. The threshold for the extreme events increases in the future scenario by an amount similar to the increase in saturation specific humidity. The results suggest robust circulation behavior for such extremes in the face of climate change.
The lower exosphere of Titan: Energetic neutral atoms absorption and imaging
Authors: Garnier P. , Dandouras I. , Toublanc D. , Roelof E. C. , Brandt P. C. , Mitchell D. G. , Krimigis S. M. , Krupp N. , Hamilton D. C. , Dutuit O. , Wahlund J.‐E.
Published: October 2008

The Saturn magnetosphere interacts with the Titan atmosphere through various mechanisms. One of them leads, by charge exchange reactions between the energetic Saturnian ions and the exospheric neutrals of Titan, to the production of energetic neutral atoms (ENAs). The Ion and Neutral Camera (INCA), one of the three sensors that comprise the Magnetosphere Imaging Instrument (MIMI) on the Cassini/Huygens mission to Saturn and Titan, images the ENA emissions in the Saturnian magnetosphere. This study focuses on the ENA imaging of Titan (for 20–50 keV H ENAs), with the example of the Ta Titan flyby (26 October 2004): our objective is to understand the positioning of the ENA halo observed around Titan. Thus we investigate the main ENA loss mechanisms, such as the finite gyroradii effects for the parent ions, or the charge stripping with exospheric neutrals. We show that multiple stripping and charge exchange reactions have to be taken into account to understand the ENA dynamics. The use of an analytical approach, taking into account these reactions, combined with a reprocessing of the INCA data, allows us to reproduce the ENA images of the Ta flyby and indicates a lower limit for ENA emission around the exobase. However, the dynamics of energetic particles through the Titan atmosphere remains complex, with an inconsistency between the ENA imaging at low and high altitudes.
The long‐term freshening and nutrient increases in summer surface water in the northern East China Sea in relation to Changjiang discharge variation
Authors: Siswanto Eko , Nakata Hideaki , Matsuoka Yuji , Tanaka Katsuhisa , Kiyomoto Yoko , Okamura Kazumaro , Zhu Jianrong , Ishizaka Joji
Published: October 2008

Using historical in situ data sets, we investigated long‐term variations in summer surface salinity and dissolved inorganic nitrogen concentration (DIN) in the northern East China Sea (ECS). From 1950 to 2002, there were interannual and decadal variations in sea surface salinity, as well as a long‐term decrease. Along with the Changjiang discharge, wind fields and surface circulations appeared to play roles in determining the interannual salinity variation. Although we attributed the long‐term decrease in surface salinity to a long‐term increase in the Changjiang discharge, the high salinity between 1978 and 1988 appeared to be associated with an increase in the Kuroshio Current transport. The increase in DIN from 1971 to 2001 appeared to be caused by a combination of changes in Changjiang discharge and an increase in nitrogen fertilizer use in China. The long‐term increase in DIN modified the nutrient composition, implying that biological production in the northern ECS changed from a DIN‐limiting to a phosphorous‐limiting. We should pay attention to changes in the northern ECS ecosystem in future decades because the volume of the Changjiang discharge, as well as its physical and chemical properties, may change dramatically because of the continuous anthropogenic perturbations and climate change.
Relaxation of high-energy heavy-ion induced bipolar plasmas in Si epilayer devices as a function of temperature
Authors: Laird Jamie S. , Onoda Shinobu , Hirao Toshio
Published: October 2008

The electronic energy loss of high-energy heavy ions striking a reverse biased junction in an electronic component designed for space induces an electron-hole pair (or bipolar) plasma with ultrahigh injection levels contained within an ionization column of submicron radial dimensions. The relaxation of this highly nonequilibrium plasma induces a large transient current on nodes coupled to the field which propagate down through external circuits, the ramification of which in some devices depends on the transient pulse shape. Pulse shape depends on the bipolar plasma decay under space-charge screening conditions, which is itself a complex function of various parameters including the junction structure, injection level, and ambipolar diffusivity. In this paper we consider the Edmonds model for describing carrier collection in a Si p+-n-n+ epilayer structure as a function of temperature. Experimental data collected from 90 to 300 K are used to examine bipolar plasma dispersion with temperature and confirm the Edmonds model.
Simulation of impulse response degradation from irradiation induced trapping and recombination regions in an InGaAs on InP photodetector
Authors: Laird Jamie S. , Onoda Shinobu , Hirao Toshio , Ohyama Hidenori
Published: October 2008

Degradation in the pulsed responsivity of an In0.53Ga0.47As on InP p-i-n photodiode due to high-energy particle irradiation induced trapping and recombination centers is simulated using quasi-three-dimensional iterative solutions to the drift-diffusion and Poisson equation in the presence of generation-recombination terms. Device physics models necessary to simulate a realistic device are discussed, and the impulse response as a function of trap density is reported for defects uniformly distributed in the InGaAs region. At high trap densities, a sharp decrease in the pulsed responsivity and an increase in dark current can be correlated with the formation of a double-field profile similar to that observed in space charge sign inverted Si and GaAs particle detectors.
A molecular dynamics study of the motion of a nanodroplet of pure liquid on a wetting gradient
Authors: Halverson Jonathan D. , Maldarelli Charles , Couzis Alexander , Koplik Joel
Published: October 2008

The dynamic behavior of a nanodroplet of a pure liquid on a wetting gradient was studied using molecular dynamics simulation. The spontaneous motion of the droplet is induced by a force imbalance at the contact line. We considered a Lennard–Jones system as well as water on a self-assembled monolayer (SAM). The motion of the droplet for the Lennard–Jones case was found to be steady with a simple power law describing its center-of-mass position with time. The behavior of the water droplet was found to depend on the uniformity of the wetting gradient, which was composed of methyl- and hydroxyl-terminated alkanethiol chains on Au(111). When the gradient was nonuniform the droplet was found to become pinned at an intermediate position. However, a uniform gradient with the same overall strength was found to drive a droplet consisting of 2000 water molecules a distance of 25nm or nearly ten times its initial base radius in tens of nanoseconds. A similar result was obtained for a droplet that was twice as large. Despite the many differences between the Lennard–Jones and water-SAM systems, the two show a similar overall behavior for the motion. Fair agreement was seen between the simulation results for the water droplet speed and the theoretical predictions. When the driving force was corrected for contact angle hysteresis, the agreement was seen to improve.
Friction based modeling of multicomponent transport at the nanoscale
Authors: Bhatia Suresh K. , Nicholson David
Published: October 2008

We present here a novel theory of mixture transport in nanopores, which considers the fluid-wall momentum exchange in the repulsive region of the fluid-solid potential in terms of a species-specific friction coefficient related to the low density transport coefficient of that species. The theory also considers nonuniformity of the density profiles of the different species, while departing from a mixture center of mass frame of reference to one based on the individual species center of mass. The theory is validated against molecular dynamics simulations for single component as well as binary mixture flow of hydrogen and methane in cylindrical nanopores in silica, and it is shown that pure component corrected diffusivities, as well as binary Onsager coefficients are accurately predicted for pore sizes sufficiently large to accommodate more than a monolayer of any of the components. It is also found that the assumption of a uniform density profile can lead to serious errors, particularly at small pore diameter, as also the use of a mixture center of mass frame of reference. The theory demonstrates the existence of an optimum temperature for any fluid, at which the fractional momentum dissipation due to wall friction is a minimum.
The Zeeman effect in the (0,0) band of the A Π7−X Σ7+ transition of manganese monohydride, MnH
Authors: Steimle Timothy C. , Wang Hailing , Gengler Jamie J. , Stoll Michael , Meijer Gerard
Published: October 2008

The Zeeman tuning of the P1(0) line (ν=17 568.35 cm−1) of the A Π7−X Σ7+ (0,0) band of manganese monohydride, MnH, has been investigated. The laser induced fluorescence spectrum of a supersonic molecular beam sample was recorded at a resolution of approximately 40 MHz and with field strengths of up to 362.0 mT. The observed spectrum was successfully fitted using a traditional effective Zeeman Hamiltonian to determine an effective magnetic g-factor for the J=2 level of the F1-spin component of the A Π7(v=0) state. Spectral predictions of the P1(0) line at field strengths used in magnetic trapping experiments are presented.
The effects of asymmetric motions on the tunneling splittings in formic acid dimer
Authors: Barnes George L. , Sibert Edwin L.
Published: October 2008

We extend the reaction surface Hamiltonian model for double proton tunneling in formic acid dimer to include all in-plane modes, except the two CH stretch modes. Zero point corrections for the out-of-plane modes are also incorporated. Transition state and equilibrium normal mode representations for the description of the asymmetric modes are developed and compared. The results compare well with reduced dimensional calculations containing just symmetric in-plane modes due to a fortuitous cancellation of tunneling contributions of the out-of-plane and in-plane asymmetric modes. The effects of scaling the potential are examined as well as the effects of asymmetric vibrational excitation on tunneling splittings. Vibrational excitation of the asymmetric dimer rock, in contrast to the symmetric rock, is found to hinder tunneling. We find qualitative agreement with the experimental measurements of Ortlieb and Havenith [J. Phys. Chem. 111, 7355 (2007)] for the tunneling splitting of the ground state; the decrease in splitting upon vibrational excitation of CO stretch, however, is overestimated.
Band gap change and interfacial reaction in Hf-silicate film grown on Ge(001)
Authors: Cho Y.-J. , Lee W. J. , Kim C. Y. , Cho M.-H. , Kim H. , Lee H. J. , Moon D. W. , Kang H. J.
Published: October 2008

The interfacial reaction of hafnium-silicate [(HfO2)x(SiO2)1−x, x=0.5,0.7] thin films grown on Ge(001) by atomic layer deposition was investigated using x-ray photoelectron spectroscopy and medium energy ion scattering spectroscopy. According to the peak changes in Hf 4f and Ge 3d, the Hf-silicate film reacted with the oxidized Ge surface forming Hf-germanate at the interface. The formation of Hf-germanate induced band bending of the Ge substrate at the interface and decreased band gap to 5.1 eV, which was lower than that of GeO2 (5.6 eV). In particular, the interfacial reaction was dependent on the amount of SiO2 in the Hf-silicate film, which resulted in more decrement in the band gap in the film with a high SiO2 fraction.
Rectification effect and electron transport property of CdS/Si nanoheterostructure based on silicon nanoporous pillar array
Authors: Xu Hai Jun , Li Xin Jian
Published: October 2008

A CdS/Si nanoheterostructure was prepared by growing CdS nanocrystallites onto silicon nanoporous pillar array. A rectification effect with an onset voltage of ∼1 V, a forward current density of ∼170 mA cm−2 at 4.5 V, a leakage current density of ∼8×10−2 mA cm−2, and a reverse breakdown voltage of ∼8 V was observed. The rectifying ratio was evaluated to be ∼215 at ±4.5 V. The electron transport across the nanoheterostructure was found to be mainly controlled by sulfur vacancies and obey the trap-limited model. These results indicate that CdS/Si nanoporous pillar array might be a promising material in fabricating photoelectronic nanodevices.
Mg
x
Zn
1
−
x
O
-based photodetectors covering the whole solar-blind spectrum range
Authors: Ju Z. G. , Shan C. X. , Jiang D. Y. , Zhang J. Y. , Yao B. , Zhao D. X. , Shen D. Z. , Fan X. W.
Published: October 2008

A series of MgxZn1−xO thin films has been prepared by metalorganic chemical vapor deposition and metal-semiconductor-metal structured ultraviolet photodetectors are fabricated from these films. The cutoff wavelengths of the photodetectors can cover the whole solar-blind spectrum range (220–280 nm) by varying Mg content in the MgxZn1−xO thin films. As a representative, the photodetector fabricated from Mg0.52Zn0.48O shows an ultraviolet/visible rejection ratio of about four orders of magnitude, and the dark current is 15 pA at 10 V bias. These results demonstrate that high-performance photodetectors operating in the whole solar-blind spectrum range can be realized in MgxZn1−xO films.
Inverted small molecule organic photovoltaic cells on reflective substrates
Authors: Tong Xiaoran , Bailey-Salzman Rhonda F. , Wei Guodan , Forrest Stephen R.
Published: October 2008

We demonstrate top-illuminated, inverted, small molecule photovoltaic cells grown on reflective substrates employing copper phthalocyanine as the donor and 3,4,9,10-perylenetetracarboxylic bis-benzimidazole as the acceptor, with a sputter-deposited transparent indium tin oxide top cathode and a metal anode, thereby reversing the conventional charge extraction properties of these contacts. The best device achieved a peak power conversion efficiency of 0.74±0.03%, reasonably consistent with the optical simulations under 1sun AM1.5G illumination giving 0.83±0.02%. This work suggests that inverted organic solar cells grown on reflective substrates have potential uses such as for power-generating coatings on opaque surfaces.
Temperature dependent dynamic and static magnetic response in magnetic tunnel junctions with Permalloy layers
Authors: Sierra J. F. , Pryadun V. V. , Aliev F. G. , Russek S. E. , García-Hernández M. , Snoeck E. , Metlushko V. V.
Published: October 2008

Ferromagnetic resonance and static magnetic properties of CoFe∕Al2O3∕CoFe∕Py and CoFe∕Al2O3∕CoFeB∕Py magnetic tunnel junctions and of 25nm thick single-layer Permalloy (Py) films have been studied as a function of temperature down to 2K. The temperature dependence of the ferromagnetic resonance excited in the Py layers in magnetic tunnel junctions shows “kneelike” enhancement of the resonance frequency accompanied by an anomaly in the magnetization near 60K. We attribute the anomalous static and dynamic magnetic response at low temperatures to interface stress induced magnetic reorientation transition at the Py interface which could be influenced by dipolar soft-hard layer coupling through the Al2O3 barrier.
Theory of analyzing free energy losses in solar cells
Authors: Brendel R. , Dreissigacker S. , Harder N.-P. , Altermatt P. P.
Published: October 2008

We make up the free energy balance for thermalized electrons and holes in a solar cell. Equations for the loss rates of free energy due to recombination and transport of carriers are derived. The well known expression for Joule heat dissipation also holds for the free energy loss by diffusive transport. All loss rates have units of mW/cm2. Thus transport losses become directly comparable in magnitude to recombination losses. The latter are usually quantified in mA/cm2 rather than mW/cm2. The impact of various loss mechanisms on the power output of the cell, also in mW/cm2, becomes directly apparent.
Three-dimensional organic field-effect transistors: Charge accumulation in the vertical semiconductor channels
Authors: Uno Mayumi , Tominari Y. , Takeya J.
Published: October 2008

A three-dimensional organic field-effect transistor is developed to accumulate charge in its vertical semiconductor channel so that space availability for the field-induced carriers is essentially multiplied. A multicolumnar structure is built incorporating a vertical layer of soluble benzothieno-benzothiophene derivative. Pronounced field-effect performance is realized with the well-defined saturation in the output, where extremely large value of channel width divided by length enables current amplification up to ∼2 μA in a square pixel even with relatively low carrier mobility of 10−4 cm2/V s. The result demonstrates usefulness of the three-dimensional structure in achieving sufficient current for matrix-controlling devices in flat-panel displays.
Measurements of evanescent wave in a sandwich Lamb wave sensor
Authors: Li Feng , Manceau Jean-François , Wu Yihui , Bastien François
Published: October 2008

One method for evanescent wave measurement of the Lamb wave biosensor is proposed by putting another Lamb wave device above the first with the distance less than the evanescent field penetration depth in the liquid. The liquid layer is sandwiched with the two Lamb wave devices. The devices are interacted by an evanescent field; thus the evanescent wave can be studied. The mode is split by the interaction of the evanescent wave. The investigation of the evanescent field gives insight into acoustic biosensors and provides precise and multiparameter measurements.
Relationships between soil temperatures and properties of fire in feathertop spinifex (Triodia schinzii (Henrard) Lazarides) sandridge desert in central Australia
Authors: Wright B. R. , Clarke P. J.
Published: October 2008

Soil temperatures during wildfires are known to influence seed bank and plant resprouting dynamics in arid Australian grasslands. Nevertheless, relationships between soil temperatures and factors such as fuel load, fuel type, season of burn, time-of-day and soil moisture are poorly understood. This study used small-scale experimental burns to determine the effects of these five variables on soil temperature profiles (0–4 cm) during fire in spinifex sandridge country in the Haasts Bluff Aboriginal Reserve, west of Alice Springs. Fuel load and type were found to strongly influence soil temperatures, with soils directly beneath Triodia hummocks experiencing more heating than hummock edges or between-hummock gaps, and soils beneath Triodia hummocks experiencing more heating than either mulga (Acacia aneura F.Muell. ex. Benth.) litter or Aristida holathera Domin. tussocks. Season and time-of-day also had strong effects on below-ground heating, with soil temperatures remaining elevated for longer periods during summer compared to winter burns, and day-time burns producing higher temperature maxima and longer durations of elevated soil temperatures than night burns. Soil moisture also had a strong impact on temperature profiles during fire, with high levels of soil moisture strongly reducing the soil heating during fire. These results indicate that the examined factors will strongly influence soil temperature regimes during spinifex wildfires. Hence, they are likely to affect the composition of plant assemblages in post-fire environments through their impacts on vegetative regeneration and on seed bank processes.
Calotrope (Calotropis procera) control
Authors: Vitelli Joseph , Madigan Barbara , Wilkinson Peter , van Haaren Peter
Published: October 2008

Calotrope [Calotropis procera (Aiton) W.T.Aiton] is an exotic shrub or small tree species that is currently invading the tropical savannahs of northern Australia. A chemical trial involving 11 herbicides and four application methods (foliar, basal bark, cut stump and soil applied) was undertaken to identify effective chemicals to control calotrope. Of the foliar herbicides tested, imazapyr provided 100% mortality at the rates applied, and the higher rate of metsulfuron-methyl killed 100% of the treated plants. The herbicides 2,4-D butyl ester, fluroxypyr, triclopyr and triclopyr/picloram killed greater than 80% of the plants when applied by a basal bark or cut stump (when cut 5 cm above ground level) method of application. Plants cut close to ground level (5 cm) were controlled more effectively than plants cut 20 cm above ground level.
Chemical control (foliar and cut stump spraying) is a cost effective tool to treat calotrope densities <800 plants/ha. Adoption of pasture management practices that promote perennial grasses, in conjunction with strategic chemical control, would further increase the effectiveness and reduce the costs of controlling vast areas of this weed.
Direct transformation from amorphous to crystalline calcium phosphate facilitated by motif-programmed artificial proteins
Authors: Tsuji Toru , Onuma Kazuo , Yamamoto Akira , Iijima Mayumi , Shiba Kiyotaka
Published: October 2008

An animal's hard tissue is mainly composed of crystalline calcium phosphate. In vitro, small changes in the reaction conditions affect the species of calcium phosphate formed, whereas, in vivo, distinct types of crystalline calcium phosphate are formed in a well-controlled spatiotemporal-dependent manner. A variety of proteins are involved in hard-tissue formation; however, the mechanisms by which they regulate crystal growth are not yet fully understood. Clarification of these mechanisms will not only lead to the development of new therapeutic regimens but will also provide guidance for the application of biomineralization in bionanotechnology. Here, we focused on the peptide motifs present in dentin matrix protein 1 (DMP1), which was previously shown to enhance hydroxylapatite (HAP) formation when immobilized on a glass substrate. We synthesized a set of artificial proteins composed of combinatorial arrangements of these motifs and successfully obtained clones that accelerated formation of HAP without immobilization. Time-resolved static light-scattering analyses revealed that, in the presence of the protein, amorphous calcium phosphate (ACP) particles increased their fractal dimension and molecular mass without increasing their gyration radii during a short period before precipitation. The protein thus facilitated reorganization of the internal structure of amorphous particles into ordered crystalline states, i.e., the direct transformation of ACP to HAP, thereby acting as a nucleus for precipitation of crystalline calcium phosphate. Without the protein, the fractal dimension, molecular mass, and gyration radii of ACP particles increased concurrently, indicating heterogeneous growth transformation.
Plasminogen mediates the atherogenic effects of macrophage-expressed urokinase and accelerates atherosclerosis in apoE-knockout mice
Authors: Kremen Michal , Krishnan Ranjini , Emery Isaac , Hu Jie Hong , Slezicki Katherine I. , Wu Alyssa , Qian Kun , Du Liang , Plawman Abigail , Stempien-Otero April , Dichek David A.
Published: October 2008

Urokinase-type plasminogen activator (uPA) is expressed at elevated levels in atherosclerotic human arteries, primarily in macrophages. Plasminogen (Plg), the primary physiologic substrate of uPA, is present at significant levels in blood and interstitial fluid. Both uPA and Plg have activities that could affect atherosclerosis progression. Moreover, correlations between increased Plg activation and accelerated atherosclerosis are reported in several human studies. However, a coherent picture of the role of the uPA/Plg system in atherogenesis has not yet emerged, with at least one animal study suggesting that Plg is atheroprotective. We used a transgenic mouse model of macrophage-targeted uPA overexpression in apolipoprotein E-deficient mice to investigate the roles of uPA and Plg in atherosclerosis. We found that macrophage-expressed uPA accelerated atherosclerotic plaque growth and promoted aortic root dilation through Plg-dependent pathways. These pathways appeared to affect lesion progression rather than initiation and to include actions that disproportionately increase lipid accumulation in the artery wall. In addition, loss of Plg was protective against atherosclerosis both in the presence and absence of uPA overexpression. Transgenic mice with macrophage-targeted uPA overexpression reveal atherogenic roles for both uPA and Plg and are a useful experimental setting for investigating the molecular mechanisms that underlie clinically established relationships between uPA expression, Plg activation, and atherosclerosis progression.
Dynamical relaying can yield zero time lag neuronal synchrony despite long conduction delays
Authors: Vicente Raul , Gollo Leonardo L. , Mirasso Claudio R. , Fischer Ingo , Pipa Gordon
Published: October 2008

Multielectrode recordings have revealed zero time lag synchronization among remote cerebral cortical areas. However, the axonal conduction delays among such distant regions can amount to several tens of milliseconds. It is still unclear which mechanism is giving rise to isochronous discharge of widely distributed neurons, despite such latencies. Here, we investigate the synchronization properties of a simple network motif and found that, even in the presence of large axonal conduction delays, distant neuronal populations self-organize into lag-free oscillations. According to our results, cortico–cortical association fibers and certain cortico–thalamo–cortical loops represent ideal circuits to circumvent the phase shifts and time lags associated with conduction delays.
Prevalence of blood and injection phobia among pregnant women
Authors: LILLIECREUTZ CAROLINE , JOSEFSSON ANN
Published: October 2008

Objective. The aim of the study was to investigate the prevalence of blood and injection phobia in an unselected pregnant population, in order to estimate the need for curative intervention programmes. Design. A cross‐sectional study. Setting. Antenatal care clinics in the southeast region of Sweden. Sample. In total, 1,606 consecutively registered pregnant women attending their first visit with a midwife. Methods. The women were asked to complete the Injection Phobia‐Anxiety scale, measuring phobic symptoms. Women who scored >20 on the questionnaire were telephone‐interviewed and then diagnosed or dismissed according to the DSM‐IV criteria for blood and injection phobia. Main outcome measures. Prevalence of blood and injection phobia according to the DSM‐IV. Results. Of 1,529 women who chose to participate (92.5%), 110 women or 7.2% fulfilled the DSM‐IV criteria for blood and injection phobia. The mean age of the women was 29.1 years. Conclusions. Blood and injection phobia is hitherto unreported in the literature, but seems to be relatively common and needs to be recognized during pregnancy as it causes a great deal of discomfort and fear among pregnant women. The Injection Phobia‐Anxiety scale is suitable as a screening tool in an antenatal care clinic setting.
Relation between neonatal jaundice and oncostatin M, hepatocyte growth factor and soluble gp130 levels in umbilical cord
Authors: NAKATSUKASA HIDEKI , MASUYAMA HISASHI , AKAHORI YOICHIRO , INOUE SEIJI , MASUMOTO AKIO , HIRAMATSU YUJI
Published: October 2008

Objectives. Oncostatin M (OSM), hepatocyte growth factor (HGF) and soluble glycoprotein 130 (sgp130) have been demonstrated to be involved in fetal liver development. In this study, we examined the relation between neonatal jaundice and OSM, gp130 or HGF levels in umbilical cord blood. Design. A cross‐sectional study of 160 neonates born at Okayama University Hospital. Setting. Tertiary referral center serving a population of three million. Methods. The serum concentrations of OSM, HGF and sgp130 in umbilical venous cord blood were measured and compared with the clinical records of these neonates. Results. The HGF level was correlated to both gestational week (p = 0.007) and birthweight (p = 0.015), as well as to total bilirubin on Day 1 (p = 0.032). In preterm neonates, the HGF levels were lower in neonates who received phototherapy (photo group) than in those who did not receive phototherapy (non‐photo group) (p = 0.002). In contrast, in term neonates, OSM levels were lower in the photo group than in the non‐photo group (p = 0.0003). Conclusions. These findings suggest that the phototherapy requirement for neonatal jaundice may be associated with lower umbilical HGF concentration in preterm neonates and with lower umbilical OSM concentration in term neonates.
Elastic coupling of limb joints enables faster bipedal walking
Authors: Dean J.C. , Kuo A.D.
Published: October 2008

The passive dynamics of bipedal limbs alone are sufficient to produce a walking motion, without need for control. Humans augment these dynamics with muscles, actively coordinated to produce stable and economical walking. Present robots using passive dynamics walk much slower, perhaps because they lack elastic muscles that couple the joints. Elastic properties are well known to enhance running gaits, but their effect on walking has yet to be explored. Here we use a computational model of dynamic walking to show that elastic joint coupling can help to coordinate faster walking. In walking powered by trailing leg push-off, the model's speed is normally limited by a swing leg that moves too slowly to avoid stumbling. A uni-articular spring about the knee allows faster but uneconomical walking. A combination of uni-articular hip and knee springs can speed the legs for improved speed and economy, but not without the swing foot scuffing the ground. Bi-articular springs coupling the hips and knees can yield high economy and good ground clearance similar to humans. An important parameter is the knee-to-hip moment arm that greatly affects the existence and stability of gaits, and when selected appropriately can allow for a wide range of speeds. Elastic joint coupling may contribute to the economy and stability of human gait.
Testing the island rule: primates as a case study
Authors: Welch John J
Published: October 2008

The island rule states that after island colonization, larger animals tend to evolve reduced body sizes and smaller animals increased sizes. Recently, there has been disagreement about how often, if ever, this rule applies in nature, and much of this disagreement stems from differences in the statistical tests employed. This study shows, how different tests of the island rule assume different null hypotheses, and that these rely on quite different biological assumptions. Analysis and simulation are then used to quantify the biases in the tests. Many widely used tests are shown to yield false support for the island rule when island and mainland evolution are indistinguishable, and so a Monte Carlo permutation test is introduced that avoids this problem. It is further shown that tests based on independent contrasts lack power to detect the island rule under certain conditions. Finally, a complete reanalysis is presented of recent data from primates. When head–body length is used as the measure of body size, reports of the island rule are shown to stem from methodological artefacts. But when skull length or body mass are used, all tests agree that the island rule does hold in primates.
Isoprenylcysteine Methylation and Demethylation Regulate Abscisic Acid Signaling inArabidopsis
Authors: Huizinga David H. , Omosegbon Olutope , Omery Bilal , Crowell Dring N.
Published: October 2008

Isoprenylated proteins bear an isoprenylcysteine methyl ester at the C terminus. Although isoprenylated proteins have been implicated in meristem development and negative regulation of abscisic acid (ABA) signaling, the functional role of the terminal methyl group has not been described. Here, we show that transgenic Arabidopsis thaliana plants overproducing isoprenylcysteine methyltransferase (ICMT) exhibit ABA insensitivity in stomatal closure and seed germination assays, establishing ICMT as a negative regulator of ABA signaling. By contrast, transgenic plants overproducing isoprenylcysteine methylesterase (ICME) exhibit ABA hypersensitivity in stomatal closure and seed germination assays. Thus, ICME is a positive regulator of ABA signaling. To test the hypothesis that ABA signaling is under feedback regulation at the level of isoprenylcysteine methylation, we examined the effect of ABA on ICMT and ICME gene expression. Interestingly, ABA induces ICME gene expression, establishing a positive feedback loop whereby ABA promotes ABA responsiveness of plant cells via induction of ICME expression, which presumably results in the demethylation and inactivation of isoprenylated negative regulators of ABA signaling. These results suggest strategies for metabolic engineering of crop species for drought tolerance by targeted alterations in isoprenylcysteine methylation.
Effects of acute and chronic angiotensin converting enzyme inhibition by spirapril on cardiovascular regulation in essential hypertensive patients. Assessment by spectral analysis and haemodynamic measurements
Authors: VEERMAN DERK P. , DOUMA CAROLINE E. , JACOBS MARIE‐CECILE , THIEN THEO , VAN MONTFRANS GERT A.
Published: October 2008

1 The effects of a first dose and of chronic treatment with spirapril, a novel angiotensin converting enzyme (ACE) inhibitor, on short‐term blood pressure and heart rate fluctuations were assessed by fast Fourier spectral analysis. The effects on systemic haemodynamics in supine and standing position were also studied. We treated 11 patients with 3 mg and 13 patients with 12 mg spirapril for 8 weeks.

2 Overall blood pressure variability was not changed by spirapril. By spectral analysis the changes in blood pressure and heart rate variability in various frequency bands can be assessed, which may be related to changes in activity of the autonomic nervous system. The relative power in the mid‐frequency band (0.08‐0.12 Hz) of supine systolic pressure was 23±10% during placebo and decreased during treatment with 12 mg to 11±4% (P <0.01 vs placebo, first dose) and to 13±6% (P <0.01, chronic treatment). Standing systolic mid‐frequency power was 38±12% during placebo and decreased to 27±9% (P <0.01 vs placebo) after the first dose of 12 mg, but it did not decrease after chronic treatment (29±13%). Treatment with 3 mg induced no changes in mid‐frequency blood pressure variability. A decrease in power of the mid‐frequency band may point to a decrease in sympathetic vascular drive. The power in the high‐frequency band (0.15‐0.40 Hz) of heart rate did not change after treatment, suggesting that there is no change in the vagal cardiac drive.

3 Supine blood pressure decreased by a decrease in vascular resistance by 16±23% (3 mg) and 14±19% (12 mg) after 8 weeks treatment. Heart rate, stroke volume and cardiac output did not change. No orthostatic hypotension occurred after the first dose. In the 12 mg group the orthostatic induced rise in heart rate (compared with supine) increased from +9±5 beats min‐1 (placebo) to +14±4 beats min‐1 (P <0.05) after the first dose. No changes in the orthostatic heart rate increase occurred in the 3 mg group. The orthostatic changes in stroke volume, cardiac output and vascular resistance were not influenced by spirapril.

4 In conclusion, the decrease in mid‐frequency blood pressure variability may suggest an inhibitory effect of acute and chronic ACE inhibition upon sympathetic vasomotor control. Vagal activity was not influenced as high–frequency heart rate variability did not change. Acute and chronic ACE inhibition did not blunt important cardiovascular reflexes, as the haemodynamic response to orthostasis remained intact.
Effect of ranitidine hydrochloride (150 mg twice daily) on the pharmacokinetics of increasing doses of ethanol (0. 15, 0.3, 0.6 g kg‐1)
Authors: BYE A. , LACEY L. F. , GUPTA S. , POWELL J. R.
Published: October 2008

1 The interaction of ranitidine hydrochloride (150 mg twice daily for 15 doses) with single doses (0.15, 0.3 and 0.6 g kg‐1) of ethanol was investigated in a placebo controlled study in 24 male subjects. Ethanol was given 1 h after a standard breakfast to maximise a drug ethanol effect if there is one. A balanced incomplete block design was used in that each subject received two of the three ethanol doses in the presence or absence of ranitidine. Blood samples (n= 18) were taken for 8h after dosing and blood ethanol concentrations (BAC) were determined by head space analysis using a validated gas liquid chromatographic method.

2 At the lowest dose of ethanol studied the pharmacokinetic profile was largely first order but at the higher doses the usual zero order kinetics were seen. Using the technique of simultaneous fitting across all doses the Km, and Vmax, constants were similar and close to literature value of 100 mg 1‐1 and 200–300 mg h 1‐1 respectively.

3 Ranitidine, in common with other H2‐receptor antagonists tested under the same experimental conditions, caused a small rise in BAC. However this was only evident at the smallest dose of ethanol studied and in common with many other publications, no effects were seen at the higher doses. The mean rise in blood ethanol following the 0.15 g kg‐1 dose was 2.6 mg dl‐1 (13.3 mg dl‐1 for placebo and 15.9 mg dl‐1 for ranitidine) and this change is of no clinical relevance.
Reduced renal fractional excretion of lithium in cystic fibrosis
Authors: BRAGER N. P. D. , REISCH N. R. C. C. H. , CHAUDHURI M. , RABIN H. R.
Published: October 2008

We hypothesized that patients with cystic fibrosis would have abnormal lithium handling because the genetic defect in cystic fibrosis encodes an ion channel which causes a generalized electrolyte transport disorder in epithelial membranes. Eight patients with cystic fibrosis and eight age‐sex matched healthy subjects ingested 600 mg lithium carbonate and had urine and serum lithium levels assessed 24 h later. Compared with healthy subjects, the patients with cystic fibrosis had higher serum lithium levels (0.071 ± 0.038 vs 0.113 ± 0.055 mmol‐1, P= 0.03) and had lower fractional renal excretion of lithium (27.5 ± 14.8 vs 18.8 ± 9.3%, P= 0.03). Caution should be used in prescribing standard doses of lithium to patients with cystic fibrosis until more definitive data are available.
Cutaneous hypersensitivity reactions to thiacetazone, HIV infection and thiacetazone concentrations in plasma
Authors: WATKINS W. M. , MUNGAI M. , MUHIA D. K. , MBERU E. K. , GATHUA S. , WINSTANLEY P. A. , GILKS's C. F. , NUNN P.
Published: October 2008

We have studied the relationship between the plasma concentration‐time profile of thiacetazone over the 24 h between doses [AUC(0,24h)] and the incidence of cutaneous reactions among HIV‐infected patients with tuberculosis in Kenya. Cutaneous reactions due to thiacetazone occurred in 4/14 [28.6%] HIV + ve patients compared with 3/47 [6.4%] HIV‐ve patients [RR = 4.48, 95% CI‐1.1 to 17.71, and all resolved on alternative therapy. Among the HIV + ve patients, those with cutaneous reactions had higher AUC(0,24h) values, although the difference was not significant. These results do not exclude pharmacokinetic change as being at least partly responsible for cutaneous reactions to TCZ in HIV + ve patients, and do not refute an immunological basis for the reaction. With regard to the operational use of TCZ in Africa, there is no indication that a modification of the dose will reduce the frequency of drug reactions.