bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolutionary diversification of pigment pattern inDaniofishes:differentialfmsdependence and stripe loss inD. albolineatus
Authors: Quigley Ian K. , Manuel Joan L. , Roberts Reid A. , Nuckels Richard J. , Herrington Emily R. , MacDonald Erin L. , Parichy David M.
Published: November 2004

The developmental bases for species differences in adult phenotypes remain largely unknown. An emerging system for studying such variation is the adult pigment pattern expressed by Danio fishes. These patterns result from several classes of pigment cells including black melanophores and yellow xanthophores, which differentiate during metamorphosis from latent stem cells of presumptive neural crest origin. In the zebrafish D. rerio,alternating light and dark horizontal stripes develop, in part, owing to interactions between melanophores and cells of the xanthophore lineage that depend on the fms receptor tyrosine kinase; zebrafish fmsmutants lack xanthophores and have disrupted melanophore stripes. By contrast,the closely related species D. albolineatus exhibits a uniform pattern of melanophores, and previous interspecific complementation tests identified fms as a potential contributor to this difference between species. Here, we survey additional species and demonstrate marked variation in the fms-dependence of hybrid pigment patterns, suggesting interspecific variation in the fms pathway or fmsrequirements during pigment pattern formation. We next examine the cellular bases for the evolutionary loss of stripes in D. albolineatus and test the simplest model to explain this transformation, a loss of fmsactivity in D. albolineatus relative to D. rerio. Within D. albolineatus, we demonstrate increased rates of melanophore death and decreased melanophore migration, different from wild-type D. rerio but similar to fms mutant D. rerio. Yet, we also find persistent fms expression in D. albolineatus and enhanced xanthophore development compared with wild-type D. rerio,and in stark contrast to fms mutant D. rerio. These findings exclude the simplest model in which stripe loss in D. albolineatusresults from a loss of fms-dependent xanthophores and their interactions with melanophores. Rather, our results suggest an alternative model in which evolutionary changes in pigment cell interactions themselves have contributed to stripe loss, and we test this model by manipulating melanophore numbers in interspecific hybrids. Together, these data suggest evolutionary changes in the fms pathway or fms requirements,and identify changes in cellular interactions as a likely mechanism of evolutionary change in Danio pigment patterns.
Fe-Rich Clays in a Weathering Profile Developed from Serpentinite
Authors: Caillaud J. , Proust D. , Righi D. , Martin F.
Published: November 2004

Bulk mineralogical and chemical properties of a weathering profile derived from serpentinite were studied using classical pedological methods (Munsell soil colors, particle-size distribution, density, cation exchange capacity, exchangeable bases, among others) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) results. Bulk clay fractions were characterized using X-ray diffraction, thermal analysis, electron microprobe, Mössbauer and infrared spectroscopies. Bulk geochemical mass-balance calculated from ICP-AES results shows leaching of both Mg and Si which reflects the early weathering of serpentine minerals. As a consequence, newly formed clay minerals are enriched with the least mobile elements, i.e. Fe and Al, producing dioctahedral smectites. These dioctahedral smectites are complex, heterogeneous and consist mainly of two populations. One population is an Fe-rich montmorillonite with little or no tetrahedral charge and Fe3+ as the dominant octahedral cation whereas the second population exhibits tetrahedral charge. Both populations occur as interstratified layers in the lower horizon of the weathering profile but show increasing segregation into well-defined end-members towards the surface horizons. Considering total Al and Fe contents, these clays differentiate into two chemical composition domains, Fe-rich clays in the lower profile and Al-rich clays towards the surface horizons.
Effects of Pyrogallol on Al13 Tridecamer Formation And Humification
Authors: Krishnamurti G. S. R. , Wang M. K. , Huang P. M.
Published: November 2004

The Al13 polycation is the predominant hydroxy-Al species in partially neutralized solutions. However, the existence of the Al13 species and the factors governing its formation in terrestrial environments still remain obscure. The objective of this study was to investigate the influence of pyrogallol, a common polyphenol in soils, on the formation of Al13 tridecamer. Hydroxy-Al solutions with an OH/Al molar ratio of 2.2 (pH 4.53) at pyrogallol/Al molar ratios of 0, 0.01, 0.05, 0.1 and 0.5 were prepared and mixed with 0.5 M sodium sulfate to form aluminum sulfate precipitation products. The solid-state 27Al nuclear magnetic resonance (NMR) spectra of the precipitates show that the pyrogallol perturbed the formation of Al13 tridecamer species as indicated by the decrease in the intensity of resonance peak, observed at 62.5 ppm, with increase in the pyrogallol/Al molar ratio. The crystallization of the precipitated Al sulfates was also hampered by pyrogallol, resulting in the formation of X-ray non-crystalline products at a pyrogallol/Al molar ratio of 0.50. The absorbance at 465 and 650 nm of the hydroxy-Al-pyrogallol solutions, the C coprecipitated, the electron spin resonance and 13C CPMAS-NMR spectra of the precipitates indicate the concomitant enhanced abiotic humification of pyrogallol by the X-ray amorphous Al species.
Adsorption and Photo-reactivity of Bensulfuron-Methyl On Homoionic Clays
Authors: Si Youbin , Wang Shenqiang , Zhou Dongmei , Chen Huaiman
Published: November 2004

The adsorption and photolysis of the herbicide bensulfuron-methyl [2-(4, 6-dimethoxypyrimidm-2-carbamoylsulfamoyl)-o-toluic acid methyl ester] on homoionic Na+-, Ca2+- and Fe3+-montmorillonite and kaolinite clays were studied. The Freundlich adsorption coefficient, Kf, measured from isotherms on clays followed the order Na+ < Ca2+ < Fe3+. Montmorillonite showed a greater adsorptive capacity than kaolinite. Analysis of Fourier transform infrared spectra of bensulfuron-methyl adsorbed on clay suggested probable bonding interactions between bensulfuron-methyl and homoionic clays. The photolysis rate of herbicide adsorbed on homoionic clay surfaces was quite slow to its free state and decreased in the order Na+ > Ca2+ > Fe3+, indicating that adsorption may have prevented photolysis.
Dickite and Other Kaolin Polymorphs from an Al-rich Clay Deposit Formed in Volcanic Tuff, Southeastern Korea
Authors: Choo Chang Oh , Kim Soo Jin
Published: November 2004

Kaolins from an Al-rich clay deposit formed in volcanic tuff, southeastern Korea contain predominant dickite and quartz with accessory diaspore, pyrophyllite, alunite, illite, sulfides and calcite. Intergrowth of blocky crystals with thin ones within stacks suggests that blocky crystals gradually replaced thin ones within the same stacks. Numerous dickite plates with pseudo-hexagonal outline are placed in rows eventually forming a U-shaped stack and a vermiform stack. Individual crystals within the stack are of pseudo-hexagonal form and vermiform, accompanying slips across basal planes. The euhedral dickite with blocky habit has basal planes (001) and edge planes (110) perpendicular to each other, and it shows pseudo-hexagonal crystallites elongated in one direction. Fourier transform infrared spectra at OH-stretching and far-infrared regions show that the dickitic mass contains a small proportion of kaolinite or nacrite, indicating interstratification or at least mixtures of kaolin polytypes. The formation of mixtures of various polytypes that are of kaolinite-dickite, dickite and mixtures of dickite-nacrite could be attributed to hydrothermal processes ranging over a broad spectrum of temperature and fluid chemistry.
The Reduction of 2,6‐Dimethoxy‐4‐chloro‐1,3,5‐triazine on Mercury Electrodes in Aqueous Solutions in Relation with the Reduction of s‐Triazine Herbicides
Authors: Rodríguez Mellado J. M. , Ruiz Montoya M. , Galvín R. Marín
Published: November 2004

This paper presents polarographic and voltammetric studies on the electroreduction of 2,6‐dimethoxy‐4‐chloro‐1,3,5‐triazine on mercury electrodes in aqueous solutions and in the acidity range 2 M H2SO4 to pH 7. Above pH 6.5 no signals were obtained. In both DC and DP polarography and voltammetry, one or two partially overlapped reduction waves were observed, depending on the pH of the medium. The overall process corresponded to a four‐electron irreversible reduction. In strongly acidic media (pH<4.5) the protonated reactant was reduced through a two‐electron process to give a dechlorinated molecule that is subsequentely reduced at the potentials of the second wave. It was concluded that the reduction of the chlorinated s‐triazine rings seems to occur through the reductive cleavage of the chlorine irrespective of the nature of the groups bonded to the ring in positions 2, 6.
Facile Synthesis of a Degradable Gel by Radical Copolymerization of Vinyl Sorbate and Molecular Oxygen
Authors: Taketani Shuji , Matsumoto Akikazu
Published: November 2004

Summary: A new kind of degradable gel was prepared by radical copolymerization of vinyl sorbate (VS) with molecular oxygen. A soluble and linear copolymer was produced at the initial stage of the polymerization and the ratio of the gel fraction was rapidly increased in the process of polymerization. An analysis of the polymerization by near infrared (NIR) spectroscopy strongly suggests that the conjugated diene group is much more reactive than the vinyl ester group. The degradation of an insoluble part (VS‐gel) was investigated by thermogravimetric (TG) and differential thermal analyses (DTA). Thermal degradation exothermically occurred around 110 °C. The weight loss of the gel was simultaneously observed. The VS‐gels obtained from polymerizations at various monomer concentrations had different physical properties, but similar degradation properties. The higher the VS monomer concentration in the feed, the lower the swelling ratio of the obtained gels due to an increase in a crosslinking density. The degradation of the VS‐gel under several stimuli other than heating was also investigated.

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The constructive completion of the space 𝒟(ℝ)
Authors: Yoshida Satoru
Published: November 2004

We prove in the framework of Bishop's constructive mathematics that the sequential completion \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$ \tilde {\cal D} $\end{document}(ℝ) of the space 𝒟(ℝ) is filter‐complete. Then it follows as a corollary that the filter‐completeness of 𝒟(ℝ) is equivalent to the principle BD‐ℕ, which can be proved in classical mathematics, Brouwer's intuitionistic mathematics and constructive recursive mathematics of Markov's school, but does not in Bishop's constructive mathematics. We also show that \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$ \tilde {\cal D} $\end{document}(ℝ) is identical with the filter‐completion which was provided by Bishop. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polynomial induction and length minimization in intuitionistic bounded arithmetic
Authors: Moniri Morteza
Published: November 2004

It is shown that the feasibly constructive arithmetic theory IPV does not prove (double negation of) LMIN(NP), unless the polynomial hierarchy CPV‐provably collapses. It is proved that PV plus (double negation of) LMIN(NP) intuitionistically proves PIND(coNP). It is observed that PV + PIND(NP ∪ coNP) does not intuitionistically prove NPB, a scheme which states that the extended Frege systems are not polynomially bounded. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A quick axiomatisation of LTL with past
Authors: Lange Martin
Published: November 2004

The paper defines focus games for satisfiability of linear time temporal logic with past operators. The games are defined in such a way that a complete axiomatisation can easily be obtained from the game rules. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reflection z‐scan measurements of opaque semiconductor thin films
Authors: Ganeev R. A. , Ryasnyansky A. I.
Published: November 2004

We studied the nonlinear refraction of semiconductor thin films (3As2S3/As2Se3 and CdS) at the wavelength of 532 nm using the reflection z‐scan technique (RZ‐scan). The values of nonlinear refractive indices γ of 3As2S3/As2Se3 and CdS were calculated to be 5 × 10–10 cm2 W–1 and –5.2 × 10–11 cm2 W–1. The comparison of RZ‐scans and transmission z‐scans was carried out for CdS film. The sign of nonlinear refraction of these chalcogenides was discussed in the framework of Kramers–Kronig transformations. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectroscopic study of decontaminated corroded carbon steel surfaces
Authors: Eng C. W. , Halada G. P. , Francis A. J. , Dodge C. J.
Published: November 2004

Removal of uranium from contaminated carbon steel surfaces by chelation with hydroxycarboxylic acid has been tested as a cleaning process for decommissioning and decontaminating contaminated surfaces. Comparison of contaminated surfaces prior to decontamination with subsequently cleaned surfaces was done in order to study the effectiveness of this cleaning technique. This was accomplished using various spectroscopic techniques, including x‐ray photoelectron spectroscopy, synchrotron infrared microspectroscopy, Rutherford backscattering spectroscopy and scanning electron microscopy/energy‐dispersive spectroscopy. Mild carbon steel (1010) coupons were exposed to uranyl nitrate solution, which led to the formation of a lightly corroded surface. Some contaminated samples underwent further cyclic humidity treatment, during which additional corrosion took place. In this study, it was found that a citric acid–hydrogen peroxide–citric acid cleaning method successfully removed uranium in lightly corroded areas. However, the method but incompletely decontaminated some heavily corroded areas where more highly crystallized corrosion products are found or where complex surface structure can occlude contaminants. Use of complementary analytical techniques is essential to provide an accurate model of surface chemistry before and after decontamination. Copyright © 2004 John Wiley & Sons, Ltd.
Stress concentration around a hyperboloidal notch under tension in a magnetoelectroelastic material
Authors: Wu X.‐H. , Shen Y.‐P. , Wang X.
Published: November 2004

A transversely isotropic magnetoelectroelastic medium made of piezoelectric BaTiO3 and magnetostrictive CoFe2O4 is bounded by a single sheeted hyperboloid of revolution which is traction, electric charges, and magnetic charges free. This solid is subjected to a finite tensile force and electric and magnetic charges at infinity. A closed‐form solution based upon the potential functions approach is obtained. The present solutions include all the solutions, such as piezoelectric, piezomagnetic, magnetostrictive, and purely elastic solutions, as special cases. Numerical examples of the tensile stress at the narrowest section are presented and show that the stress concentration is significantly affected by material property and applied electric charges, and not appreciably influenced by magnetic charges.
Material characterization of a Kelvin chain from dynamic response
Authors: Ram Y.M. , Voyiadjis G.Z.
Published: November 2004

The springs and dampers comprising a Kelvin chain can be determined from dynamic test data. The paper shows how to construct the parameters of the chain by using: (a) the dynamic response data to constant load, and (b) the poles and zeros of a collocated transfer function at the end of the chain. The results may be used in characterizing the material properties of a sample from laboratory experimental data.
‘THIS HORRID HOLE’: ROYAL AUTHORITY, COMMERCE AND CREDIT AT BONNY, 1690–1840
Authors: LOVEJOY PAUL E. , RICHARDSON DAVID
Published: November 2004

This article suggests that differences in local political structures and credit protection regimes largely account for Bonny's displacement of Old Calabar as the principal slave port of the Bight of Biafra in the eighteenth century, despite Bonny's reputation for being particularly unhealthy for Europeans. We argue that this displacement occurred in the 1730s, several decades earlier than previously thought. We suggest that this was made possible by the early growth and consolidation of royal authority at Bonny. The use of state authority to enforce credit arrangements in Bonny proved more effective than the mechanisms adopted at its closest rival, Old Calabar, where, in the absence of a centralized political authority similar to the monarchy at Bonny, credit protection before 1807 was based on pawnship.
REGULATING THE SOCIAL: SOCIAL SECURITY, SOCIAL WELFARE AND THE STATE IN LATE COLONIAL TANZANIA
Authors: ECKERT ANDREAS
Published: November 2004

This essay discusses British discourses and efforts to regulate social policy in both urban and rural areas in late colonial Tanzania. It focuses mainly on questions of social security and especially on the vague concept of social welfare and development, which after the Second World War became a favoured means of expressing a new imperial commitment to colonial people. The British were very reluctant about implementing international standards of social security in Tanganyika, mainly due to the insight that the cost of providing European-scale benefits could not be borne by the colonial regime in such a poor territory. They were far more enthusiastic in pursuing a policy of social development, embodied in social welfare centres and various other schemes. It is argued that in Tanzania, this policy remained focused on peasantization rather than on proletarianization and was characterized by a disconnection between Colonial Office mandarins in London, attempting to create bourgeois, respectable African middle classes, and colonial officials in Tanganyika, seeking to maintain the political legitimacy of the chiefs and headmen. Most Africans ignored rather than challenged many of these state efforts. However, the nationalist party, the Tanganyika African National Union (TANU) under Julius Nyerere believed in these programmes and continued such dirigiste and poorly financed improvement schemes after independence.
Grain grower perceptions and use of integrated weed management
Authors: Llewellyn R. S. , Lindner R. K. , Pannell D. J. , Powles S. B.
Published: November 2004

Greater adoption of integrated weed management, to reduce herbicide reliance, is an objective of many research and extension programmes. In Australian grain-growing regions, integrated weed management is particularly important for the management of herbicide resistance in weeds. In this study, survey data from personal interviews with 132 Western Australian grain growers are used to characterise the use and perceptions of integrated weed management practices. The main objective was to identify opportunities for improved weed management decision making, through targeted research and extension. The extent to which integrated weed management practices are used on individual farms was measured. Perceptions of the efficacy and reliability of various weed management practices were elicited for control of annual ryegrass (Lolium rigidum Gaud.), along with perceptions of the economic value of integrated weed management practices relative to selective herbicides. All growers were shown to be using several integrated weed management practices, although the use of some practices was strongly associated with the presence of a herbicide-resistant weed population. In general, both users and non-users were found to have high levels of awareness of integrated weed management practices and their weed control efficacy. Herbicide-based practices were perceived to be the most cost-effective. Opportunities for greater adoption of integrated weed management practices, to conserve the existing herbicide resource, exist where practices can be shown to offer greater shorter-term economic value, not necessarily just in terms of weed control, but to the broader farming system.
If long fallow cropping is leaky then shallow groundwaters on the Liverpool Plains should be of recent origin
Authors: Young R. R. , Broughton A. , Bradd J. M. , Holland J. F.
Published: November 2004

Previous groundwater studies have indicated that up to 195 000 ha of the Liverpool Plains catchment, south of Gunnedah, New South Wales, Australia, are at risk from shallow saline watertables. Replacement of hydraulically stable, native perennial grasslands with more ‘leaky’ annual cropping systems since the 1950s, particularly long fallow wheat–sorghum rotations, has been held responsible for an apparent increased frequency of shallow watertables and saline discharge. If so, then it follows that shallow groundwater in the alluvium will be recent (less than about 30 years old) and the solution to the problem is a straightforward reduction in deep drainage under farming systems via increased evapotranspiration. However, in this study, we have found levels of bomb pulse tritium in shallow groundwaters that indicate that about half of the shallow groundwaters in the Mooki subcatchment pre-date current agricultural practices. A hypothesis for this unexpected outcome suggests that the problem is complex and that solutions need to be site-specific.
Social supports and serotonin transporter gene moderate depression in maltreated children
Authors: Kaufman Joan , Yang Bao-Zhu , Douglas-Palumberi Heather , Houshyar Shadi , Lipschitz Deborah , Krystal John H. , Gelernter Joel
Published: November 2004

In this study, measures of the quality and availability of social supports were found to moderate risk for depression associated with a history of maltreatment and the presence of the short (s) allele of the serotonin transporter gene promoter polymorphism (5-HTTLPR). The present investigation (
i
) replicates research in adults showing that 5-HTTLPR variation moderates the development of depression after stress, (
ii
) extends the finding to children, and (
iii
) demonstrates the ability of social supports to further moderate risk for depression. Maltreated children with the s/s genotype and no positive supports had the highest depression ratings, scores that were twice as high as the non-maltreated comparison children with the same genotype. However, the presence of positive supports reduced risk associated with maltreatment and the s/s genotype, such that maltreated children with this profile had only minimal increases in their depression scores. These findings are consistent with emerging preclinical and clinical data suggesting that the negative sequelae associated with early stress are not inevitable. Risk for negative outcomes may be modified by both genetic and environmental factors, with the quality and availability of social supports among the most important environmental factors in promoting resiliency in maltreated children, even in the presence of a genotype expected to confer vulnerability for psychiatric disorder.
The V proteins of paramyxoviruses bind the IFN-inducible RNA helicase, mda-5, and inhibit its activation of the
IFN
-β promoter
Authors: Andrejeva J. , Childs K. S. , Young D. F. , Carlos T. S. , Stock N. , Goodbourn S. , Randall R. E.
Published: November 2004

Most paramyxoviruses circumvent the IFN response by blocking IFN signaling and limiting the production of IFN by virus-infected cells. Here we report that the highly conserved cysteine-rich C-terminal domain of the V proteins of a wide variety of paramyxoviruses binds melanoma differentiation-associated gene 5 (mda-5) product. mda-5 is an IFN-inducible host cell DExD/H box helicase that contains a caspase recruitment domain at its N terminus. Overexpression of mda-5 stimulated the basal activity of the
IFN-
β promoter in reporter gene assays and significantly enhanced the activation of the
IFN-
β promoter by intracellular dsRNA. Both these activities were repressed by coexpression of the V proteins of simian virus 5, human parainfluenza virus 2, mumps virus, Sendai virus, and Hendra virus. Similar results to the reporter assays were obtained by measuring IFN production. Inhibition of mda-5 by RNA interference or by dominant interfering forms of mda-5 significantly inhibited the activation of the
IFN-
β promoter by dsRNA. It thus appears that mda-5 plays a central role in an intracellular signal transduction pathway that can lead to the activation of the
IFN-
β promoter, and that the V proteins of paramyxoviruses interact with mda-5 to block its activity.
Combinatorial antibody libraries from cancer patients yield ligand-mimetic Arg-Gly-Asp-containing immunoglobulins that inhibit breast cancer metastasis
Authors: Felding-Habermann Brunhilde , Lerner Richard A. , Lillo Antonietta , Zhuang Shufei , Weber Martin R. , Arrues Sandra , Gao Changshou , Mao Shenlan , Saven Alan , Janda Kim D.
Published: November 2004

Combinatorial antibody libraries have the potential to display the entire immunological record of an individual, allowing one to detect and recover any antibody ever made, irrespective of whether it is currently being produced. We have termed this the “fossil record” of an individual's antibody response. To determine whether cancer patients have ever made antibodies with disease-fighting potential, we screened combinatorial antibody libraries from cancer patients for immunoglobulins that can identify metastatic tumor cells. This strategy yielded human antibodies specific for the activated conformation of the adhesion receptor integrin αvβ3 that is associated with a metastatic phenotype. In a remarkable example of convergent evolution, two of these antibodies were shown to contain the Arg-Gly-Asp integrin recognition motif of the natural ligand within the third complementarity-determining region of the heavy chain. These antibodies interfered with lung colonization by human breast cancer cells in a mouse model and inhibited existing metastatic disease. Our data imply that, at least at some time, these antibodies were part of a patient's surveillance system against metastatic cells, targeting the activated conformer of integrin αvβ3 and disrupting its functions. The ligand-mimetic nature of these antibodies, combined with specificity for a single receptor, is unique in the integrin–ligand repertoire. The convergent evolution of critical sequences in antibodies and other ligands that bind to the same target means that the immune response has sufficient power to find a best chemical solution for the optimization of binding energy, even though antibodies evolve in real time, as compared with billions of years for the natural ligand.
Quantitative Imaging of Single Live Cells Reveals Spatiotemporal Dynamics of Multistep Signaling Events of Chemoattractant Gradient Sensing inDictyostelium
Authors: Xu Xuehua , Meier-Schellersheim Martin , Jiao Xuanmao , Nelson Lauren E. , Jin Tian
Published: November 2004

Activation of G-protein-coupled chemoattractant receptors triggers dissociation of Gα and Gβγ subunits. These subunits induce intracellular responses that can be highly polarized when a cell experiences a gradient of chemoattractant. Exactly how a cell achieves this amplified signal polarization is still not well understood. Here, we quantitatively measure temporal and spatial changes of receptor occupancy, G-protein activation by FRET imaging, and PIP3levels by monitoring the dynamics of PHCrac-GFP translocation in single living cells in response to different chemoattractant fields. Our results provided the first direct evidence that G-proteins are activated to different extents on the cell surface in response to asymmetrical stimulations. A stronger, uniformly applied stimulation triggers not only a stronger G-protein activation but also a faster adaptation of downstream responses. When naïve cells (which have not experienced chemoattractant) were abruptly exposed to stable cAMP gradients, G-proteins were persistently activated throughout the entire cell surface, whereas the response of PHCrac-GFP translocation surprisingly consisted of two phases, an initial transient and asymmetrical translocation around the cell membrane, followed by a second phase producing a highly polarized distribution of PHCrac-GFP. We propose a revised model of gradient sensing, suggesting an important role for locally controlled components that inhibit PI3Kinase activity.
TheCaenorhabditis elegansUNC-14 RUN Domain Protein Binds to the Kinesin-1 and UNC-16 Complex and Regulates Synaptic Vesicle Localization
Authors: Sakamoto Rie , Byrd Dana T. , Brown Heather M. , Hisamoto Naoki , Matsumoto Kunihiro , Jin Yishi
Published: November 2004

Kinesin-1 is a heterotetramer composed of kinesin heavy chain (KHC) and kinesin light chain (KLC). The Caenorhabditis elegans genome has a single KHC, encoded by the unc-116 gene, and two KLCs, encoded by the klc-1 and klc-2 genes. We show here that UNC-116/KHC and KLC-2 form a complex orthologous to conventional kinesin-1. KLC-2 also binds UNC-16, the C. elegans JIP3/JSAP1 JNK-signaling scaffold protein, and the UNC-14 RUN domain protein. The localization of UNC-16 and UNC-14 depends on kinesin-1 (UNC-116 and KLC-2). Furthermore, mutations in unc-16, klc-2, unc-116, and unc-14 all alter the localization of cargos containing synaptic vesicle markers. Double mutant analysis is consistent with these four genes functioning in the same pathway. Our data support a model whereby UNC-16 and UNC-14 function together as kinesin-1 cargos and regulators for the transport or localization of synaptic vesicle components.
CHARACTERISTICS OF PHOSPHORUS LIMITATION IN CHLAMYDOMONAS REINHARDTH (CHLOROPHYCEAE) AND ITS PALMELLOIDS1
Authors: Olsen Ynguar , Knutsen Gjert , Lien Torleiv
Published: November 2004

Chlamydomonas reinhardtii Dang, was grown in a chemostat culture under phosphate limitation. The steady state concentration of phosphate was below the detection limit (< 1 μg P/L) in all runs. The cellular content of phosphorus (Qp), polyphosphate (Qpp) and chlorophyll a increased with increasing dilution rate, and the growth rate of the alga was described by Qp as well as Qpp in the Droop model. The ratio Qpp/Qp and the activity of alkaline phosphatase were maximal at high and low growth rates, respectively. Palmelloids of Chlamydomonas were found at high dilution rates (D > 0.12 h−1) and became attached to the wall of the culture vessel. They differed from the vegetative stage in both chemical composition and growth rate. Their contents of phosphorus and chlorophyll a were low, as in the vegetative cells, which grew at a low growth rate, whereas the ration Qpp/Qp and the activity of alkaline phosphatase were comparable with those of fast growing vegetative cells. The growth rate of the palmelloids was 0.03 h−1 whereas maximum growth rate (μm) for the vegetative cells was 0.21 h−1.
Primed by the Euro: The Impact of a Referendum Campaign on Public Opinion and Evaluations of Government and Political Leaders
Authors: De Vreese Claes H.
Published: November 2004

The premise of political priming is that public evaluations of political leaders are made on the basis of issues that are on the top of citizens’ minds. This study investigated the impact of a national referendum campaign about a European integration issue on the evaluation of the incumbent government, the prime minister, and the opposition leaders. Drawing on a content analysis of news media and a two‐wave panel survey, the results showed that as the topic of the referendum (the introduction of the euro) became more visible in the media during the campaign the importance of the euro issue for formulating general evaluations of political leaders increased. The incumbent government that was seen to handle the referendum poorly was penalized by the referendum. Exposure to news media outlets that covered the referendum extensively and offered negative evaluations of political leaders boosted the decline in the overall performance rating of political leaders by politically less involved respondents. These results stress the necessity of considering the campaign and the specific content of the media to understand fluctuations in public opinion during a referendum campaign. The study concludes with a discussion of the implications of a referendum campaign for political leaders.
The gift of education: An anthropological perspective on the commoditization of learning
Authors: Cooper Paul
Published: November 2004

Cited from an online BBC News report on 19 February 2003. http://news.bbc.co.uk

Cited in the Times Higher Education Supplement (16 May 2003: 3).

Most of these students are, however, exempt from the payment of fees under current regulations.

It may be objected that the sorts of characteristics I describe here, pertaining to the professional relations obtaining between teachers and students, may be widespread in a variety of client‐professional relationships, such as between, say, doctor and patient, lawyer and client, etc. This may indeed be so in any given case. However, I regard education as the paradigm of a professional relationship that is predicated upon the characteristics of gift exchange.

This point can, I think, be made equally well in respect of the minority of academics who are less than fully committed to their teaching activities and to their students.

The arguments I advance throughout this piece suggest that we should think very carefully about how to employ to best effect such devices as e‐learning technologies and distance learning resources.

An article in the Times Higher Education Supplement (14 November 2003: 20) raises many of these questions, together with the issue of ‘commoditization’, but does so with a focus on the views of parents of university students.
Homing behaviour of juvenile Australian raspy crickets (Orthoptera: Gryllacrididae)
Authors: Hale Roderick J. , Bailey Winston J.
Published: November 2004

Abstract. Juvenile gryllacridid Orthoptera, known as raspy crickets, build nests or burrows as soon as they hatch. Both juveniles and adults are central place foragers that search for food at night and return to the same nest each morning. This study examines the homing abilities of juveniles of an undescribed species of gryllacridid from Western Australia. Juveniles were placed in a simple maze, which consisted of two chambers, one containing the nest and the other empty, linked by wide glass tubes to a central chamber containing food. The food was placed in this chamber with a consistent orientation relative to the exit tubes leading to the nest and empty chambers. Juveniles appeared to learn which chamber contained their nest and thereafter ignored the route towards the empty chamber. By exchanging the connecting glass tubes, it could be established that juvenile crickets were not using chemical trails to find their home. The positions of the empty and nest chambers with respect to the central chamber were exchanged and, in a separate manipulation, the spatial configuration of the food in the central chamber was also changed. Both manipulations resulted in a decrease in successful returns to the nest chamber, the former because the nest had been relocated, the latter presumably because the spatial arrangement of items within the food chamber now presented orientation cues, which led to the empty chamber. Furthermore, juveniles were able to estimate distance travelled, despite the absence of chemical or visual cues. Juvenile raspy crickets appear to be able to maintain nest fidelity from a very early age by using spatial landmarks and appear capable of measuring translational displacement intrinsically.
Movement of the grape berry moth,Endopiza viteana: displacement distance and direction
Authors: Botero‐Garcés Natalia , Isaacs Rufus
Published: November 2004

Abstract. Mark–release–recapture is used to quantify displacement by adults of the North American grape berry moth,Endopiza viteanaClemens (Lepidoptera: Tortricidae) under field conditions. Moths marked with fluorescent dust are released eight times in the centre of a vineyard over 2 years, and recaptured using pheromone traps and interception traps. In vineyards, male moths are recaptured an average of 13.8 ± 0.8 m from the release site (maximum 58.2 m), whereas female displacement is similar with average flight distances of 11.4 ± 6.7 m (maximum 41.2 m). Increasing wind speed during moth flight activity periods suppresses displacement by both sexes, and females are less likely than males to fly in winds above 0.6 m s−1. The majority of males are recaptured upwind from the release site or at a tangent to the overall mean wind direction when responding to pheromone traps, whereas female moths trapped in interception traps exhibit a large variability in direction from the release point. Releases of marked moths in woods adjacent to a vineyard demonstrates interhabitat movement byE. viteanamales and by a single female. The average maximum displacement by males during interhabitat movement is 105.4 ± 3.9 m, significantly greater than the average maximum of 39.7 ± 6.7 m inside the vineyard habitat.
Some characteristics of the visual perception of the ant Myrmica sabuleti
Authors: Cammaerts Marie‐Claire
Published: November 2004

Abstract.  Using classical conditioning techniques, this study aims to determine what the ant Myrmica sabuleti can see and discriminate. It appears that workers see distinctly vertical as well as horizontal segments 1, 2, 3, 5, 10 and 15 mm wide and 1, 2, 3, 5, 10 and 15 cm long. They can also see distinctly horizontal segments (0.5 × 3 cm) located at 1, 2, 3, 5 and 10 cm height, but do not see such a segment situated at 15 cm height. This allowed the assessment of their maximum distance of vision. Myrmica sabuleti workers also see distinctly vertical segments (0.5 × 3 cm) sloping backwards towards the horizontal at different angles (90, 60, 45, 30, 15 and 0 °). Consequently, M. sabuleti workers see cues lying horizontally on the ground and have a stereovision of a portion of their environment. The species also see distinctly black circles of different sizes located horizontally above them. Thus, they are able to see distinctly slightly modified patterns located aside, below, above as well as before them, and have a small area of binocular vision that both eyes can look at. Myrmica sabuleti workers' maximum distance of vision is directly proportional to the square root of the surface of the object observed. Consequently, the smallest vision angular subtense of an object needed to elicit a reaction in M. sabuleti workers is evaluated as being approximately 5 angular degrees.
Effect of Managed Care Enrollment on Primary and Repeat Cesarean Rates Among U.S. Department of Defense Health Care Beneficiaries in Military and Civilian Hospitals Worldwide, 1999–2002
Authors: Linton Andrea , Peterson Michael R.
Published: November 2004

Abstract:  Background: In response to rising cesarean rates, it is reasonable for health care organizations to look to a managed care model as a means of controlling further rate increases. However, little conclusive evidence exists to support this solution. We undertook a study of the Department of Defense health care beneficiary population to assess the impact of enrollment in TRICARE Prime, the Department's managed care health plan, on cesarean delivery rates. Methods: Pooled hospital discharge records from 1999–2002 for live, singleton births were analyzed to calculate primary and repeat cesarean rates for TRICARE Prime and non‐Prime beneficiaries in the military and civilian hospitals that comprise the Department of Defense health care network. Stepwise logistic regression was used to calculate adjusted odds ratios for clinical indicators for each combination of health plan and hospital setting using theχ2difference(p < 0.05)to eliminate nonsignificant variables from the model. Total primary and repeat cesarean rates were compared with primary and repeat cesarean rates for women with no reported clinical complications to account for differences in case mix across subgroups. Statistical significance of the differences calculated for subgroups was assessed usingχ2. Results: Primary cesarean rates were significantly lower for TRICARE Prime enrollees relative to non‐Prime beneficiaries for all race subgroups and three of five age subgroups in military hospitals and four of five age subgroups in civilian hospitals. No significant differences in repeat cesarean rates were observed between Prime and non‐Prime beneficiaries within any race or age subgroup. Breech presentation followed by dystocia, fetal distress, and other complications were significant predictors for primary cesarean. Previous cesarean delivery was the leading predictor for repeat cesarean delivery. Primary and repeat cesarean rates observed for military hospitals were consistently lower than rates observed for civilian hospitals within each health plan type and age group. Conclusions: Enrollment in the managed care health plan was significantly associated with lower risk of primary cesarean delivery relative to membership in other health plans offered to Department of Defense health care beneficiaries. Repeat cesarean rates in this population varied independently of health plan type. Primary cesarean delivery was generally associated with clinical complications, whereas previous cesarean delivery was the strongest indictor for a repeat cesarean delivery. A clear explanation of reduced cesarean rates for Prime enrollees remains elusive, but it is likely that factors beyond individual practitioner decision‐making were at work.
Expression of the liver‐specific gene Cyp7a1 reveals hepatic differentiation in embryoid bodies derived from mouse embryonic stem cells
Authors: Asahina Kinji , Fujimori Hiroaki , Shimizu‐Saito Keiko , Kumashiro Yuji , Okamura Kentaro , Tanaka Yujiro , Teramoto Kenichi , Arii Shigeki , Teraoka Hirobumi
Published: November 2004

Hepatic differentiation from mouse embryonic stem (ES) cells via the formation of embryoid bodies (EBs) has been revealed by the expression of hepatocyte‐related genes such as α‐fetoprotein and albumin. It is known, however, that the visceral endoderm differentiates in early EBs and expresses these hepatocyte‐related genes. Thus, it remains unclear whether ES cells are capable of differentiating into hepatocytes derived from definitive endoderm in vitro. In the present study, yolk sac tissues isolated from the foetal mouse were found to express many hepatocyte‐related genes. Among the hepatocyte‐related genes examined, cytochrome P450 7A1 (Cyp7a1) was identified as a liver‐specific gene that was not expressed in the yolk sac. Cyp7a1 was induced in developing EBs, and hepatic differentiation was preferentially observed in the developing EBs in attached culture as compared to those in suspension culture. Leukaemia inhibitory factor permitted the differentiation of visceral endoderm, but inhibited the expression of gastrulation‐related genes and the hepatic differentiation in cultured EBs. ES cells expressing green fluorescent protein (GFP) under the control of the Cyp7a1 enhancer/promoter showed that cultured EBs contained GFP‐positive epithelial‐like cells. These results demonstrate that ES cells can differentiate in vitro into hepatocytes derived from definitive endoderm.
Acquired factor VIII inhibitors in non‐haemophilic patients: clinical experience of 15 cases
Authors: Huang Y.‐W. , Saidi P. , Philipp C.
Published: November 2004

Summary.  We retrospectively analysed 15 non‐haemophilic patients with acquired factor VIII inhibitors seen in our regional haemophilia centre. The median age was 55 years (range: 21–80). About 70% of patients older than 50 were male, while all five patients younger than 50 were female. The most common underlying condition was pregnancy or postpartum status (20%). About 27% of cases had no identifiable underlying condition. About 27% of patients had medical conditions that were unlikely to be related to acquired inhibitors. The most frequent presenting symptom was spontaneous haemorrhage of soft tissues, skin or joints. Twelve of 13 (92.3%) evaluable patients achieved complete remission (CR) with prednisone alone and/or combined prednisone and cyclophosphamide, but their clinical courses were highly variable. The median time to response was 21.5 weeks (range: 2–176) and the median treatment duration was 9 months (range: 1.25–66). All six patients treated with prednisone initially, and then combined prednisone/cyclophosphamide if no response (NR) to prednisone within 3–4 months (three patients), achieved CR; while four of five patients treated initially with combined prednisone/cyclophosphamide had CR. Patients older than 50 years had a similar response rate, median time to response and median treatment duration as did patients younger than 50 years (83% vs. 100%; 21.5 vs. 32 weeks, and 8 vs 16.5 months, respectively). Furthermore, the differences in the median time to response and treatment duration for patients with high or low baseline or peak inhibitor titres were negligible. Only one patient died of a treatment‐related pulmonary aspergillosis 18 months after an acquired inhibitor was diagnosed. None of these patients died of bleeding complications.

In conclusion, our patients with acquired FVIII inhibitor had highly variable clinical courses and responses to steroid or immunosuppressive therapy. The inhibitors in the majority of patients resolved in less than 6 months although in two cases it persisted for longer than 1 year before resolving. Treatment with prednisone alone as first line, then combined prednisone with cyclophosphamide if NR to prednisone seemed equally effective when compared with using combined prednisone and cyclophosphamide initially. Further studies of newer therapeutic agents such as 2‐chlorodeoxyadenosine (2‐CDA) and rituximab are warranted for patients refractory to conventional immunosupressive therapy.
The applicability of Rapoport's rule to the marine molluscs of the Americas
Authors: Fortes R. R. , Absalão R. S.
Published: November 2004

Aim  We evaluated the applicability of Rapoport's rule (RR) to the marine molluscs of the Americas. The biogeographical pattern predicted by RR has been the subject of a large number of studies, some supporting it and some not. In this exercise, we attempted to generate results free of biases in taxonomy or geographical scale.

Location  The study area encompassed the Pacific and Atlantic sides of the entire North and South American continents.

Methods  Our analysis was based on secondary data. We tested the relationship of the geographical range to gradients of latitude and depth, using the methodologies of Stevens (1989) and midpoint (Rohde et al., 1993). By Spearman's correlation, we related the mean amplitude of the geographical distribution to each gradient. We compared all known molluscan species together, and performed a second analysis limited to certain taxonomically well‐known groups.

Results  Our results were generated from a databank encompassing 4067 species. The analyses corroborated RR on both the Pacific and Atlantic coasts. In applying the pattern to the Atlantic coast, certain methodological issues had to be considered, such as the exclusion of deep‐water species and taxonomically biased groups. Regional features, such as the size of a biogeographical province, seemed to strongly affect the form of the pattern. The results also supported the association of RR with a depth gradient.