bluuebunny/crossref_metadata_2025 huggingface dataset:
Studying Oil, Islam, and Women as if Political Institutions Mattered
Authors: Kang Alice
Published: November 2009

By asserting that oil, not Islam, hurts gender equality, Michael Ross (2008) has made an important contribution to the debate on whether Islam bodes ill for women (Fish 2002; Inglehart and Norris 2003; Spierings, Smits, and Verloo 2009). Ross suggests that oil production decreases the number of female workers in countries with occupational segregation. The more women are left out of the formal economy, the fewer opportunities and resources they have for becoming influential political constituencies. According to Ross, “[t]his leaves oil-producing states with atypically strong patriarchal cultures and political institutions” (p. 107). Employing the same set of countries and data used in Ross (2008), I show that the institution of gender quotas, which is omitted from his statistical analyses, offsets the effects of oil rents on women's political representation. Gender quotas increase women's representation in Muslim majority and non-Muslim majority countries and in countries that are oil rich and oil poor. That “petroleum perpetuates patriarchy” (p. 120) is a tendency, not destiny.
Does Oil Wealth Hurt Women? A Reply to Caraway, Charrad, Kang, and Norris
Authors: Ross Michael L.
Published: November 2009

I am grateful to the editors of Politics & Gender for organizing this exchange. I agree with many of the points raised by Teri Caraway, Mounira Charrad, and Alice Kang, but disagree sharply with Pippa Norris.
Physically based modeling of bedrock incision by abrasion, plucking, and macroabrasion
Authors: Chatanantavet Phairot , Parker Gary
Published: November 2009

Many important insights into the dynamic coupling among climate, erosion, and tectonics in mountain areas have derived from several numerical models of the past few decades which include descriptions of bedrock incision. However, many questions regarding incision processes and morphology of bedrock streams still remain unanswered. A more mechanistically based incision model is needed as a component to study landscape evolution. Major bedrock incision processes include (among other mechanisms) abrasion by bed load, plucking, and macroabrasion (a process of fracturing of the bedrock into pluckable sizes mediated by particle impacts). The purpose of this paper is to develop a physically based model of bedrock incision that includes all three processes mentioned above. To build the model, we start by developing a theory of abrasion, plucking, and macroabrasion mechanisms. We then incorporate hydrology, the evaluation of boundary shear stress, capacity transport, an entrainment relation for pluckable particles, a routing model linking in‐stream sediment and hillslopes, a formulation for alluvial channel coverage, a channel width relation, Hack's law, and Exner equation into the model so that we can simulate the evolution of bedrock channels. The model successfully simulates various features of bed elevation profiles of natural bedrock rivers under a variety of input or boundary conditions. The results also illustrate that knickpoints found in bedrock rivers may be autogenic in addition to being driven by base level fall and lithologic changes. This supports the concept that bedrock incision by knickpoint migration may be an integral part of normal incision processes. The model is expected to improve the current understanding of the linkage among physically meaningful input parameters, the physics of incision process, and morphological changes in bedrock streams.
Regional low‐flow frequency analysis using single and ensemble artificial neural networks
Authors: Ouarda T. B. M. J. , Shu C.
Published: November 2009

In this paper, artificial neural networks (ANNs) are introduced to obtain improved regional low‐flow estimates at ungauged sites. A multilayer perceptron (MLP) network is used to identify the functional relationship between low‐flow quantiles and the physiographic variables. Each ANN is trained using the Levenberg‐Marquardt algorithm. To improve the generalization ability of a single ANN, several ANNs trained for the same task are used as an ensemble. The bootstrap aggregation (or bagging) approach is used to generate individual networks in the ensemble. The stacked generalization (or stacking) technique is adopted to combine the member networks of an ANN ensemble. The proposed approaches are applied to selected catchments in the province of Quebec, Canada, to obtain estimates for several representative low‐flow quantiles of summer and winter seasons. The jackknife validation procedure is used to evaluate the performance of the proposed models. The ANN‐based approaches are compared with the traditional parametric regression models. The results indicate that both the single and ensemble ANN models provide superior estimates than the traditional regression models. The ANN ensemble approaches provide better generalization ability than the single ANN models.
Chlorine isotope variations along the Central American volcanic front and back arc
Authors: Barnes J. D. , Sharp Z. D. , Fischer T. P. , Hilton D. R. , Carr M. J.
Published: November 2009

Volcanic outputs (ash, tephra, and lava samples) of 23 volcanic centers from the volcanic front, secondary front, and back arc in Central America were analyzed for their δ37Cl values with the goal of using chlorine isotopes as a tracer of fluids sourced from the subducting Cocos slab. δ37Cl values range from −2.6 to +3.0‰ with systematic variations along the length of the front. Values from the northernmost (Guatemala and El Salvador) and southernmost (Costa Rica) ends of the front have mantle‐like signatures. In contrast, δ37Cl values are both positive and negative in the center of the front (Nicaragua), implying a sediment and/or serpentinite‐derived component. Geophysical observations are consistent with extensive hydration of the Cocos plate offshore of Nicaragua, in support of a serpentinite‐derived fluid source. Fluids from dehydrating serpentinites may also incorporate Cl from overlying sediments, resulting in a multiple‐source chlorine signature.
Modification of the lithospheric stress field by lateral variations in plate‐mantle coupling
Authors: Naliboff J. B. , Conrad C. P. , Lithgow‐Bertelloni C.
Published: November 2009

The presence of deeply penetrating continental roots may locally increase the magnitude of basal shear tractions by up to a factor of 4 compared to a layered viscosity structure. Here we examine how these increases in mantle‐lithosphere coupling influence stress patterns in the overlying elastic lithosphere. By coupling a mantle flow model to a model for the elastic lithosphere, we show that the amplification of mantle tractions beneath cratons increases elastic stress magnitudes by at most a factor of only 1.5 in a pattern not correlated to local basal traction changes. This disconnect is explained by the transmission of elastic stresses across large distances, which makes them sensitive to regionally‐averaged changes in basal tractions, but not local variations. Our results highlight the importance of regional variations in lithospheric strength, which could allow stress patterns to more closely match regional changes in basal shear.
First in situ observation of the Moon‐originating ions in the Earth's Magnetosphere by MAP‐PACE on SELENE (KAGUYA)
Authors: Tanaka Takaaki , Saito Yoshifumi , Yokota Shoichiro , Asamura Kazushi , Nishino Masaki N. , Tsunakawa Hideo , Shibuya Hidetoshi , Matsushima Masaki , Shimizu Hisayoshi , Takahashi Futoshi , Fujimoto Masaki , Mukai Toshifumi , Terasawa Toshio
Published: November 2009

In contrast to many ground‐based optical observations of the thin lunar alkali exosphere, in situ observations of the exospheric ions by satellite‐borne plasma instruments have been quite rare. MAP‐PACE‐IMA onboard Japanese lunar orbiter SELENE (KAGUYA) succeeded in detecting Moon originating ions at 100 km altitude. Here we make the first report of the ion detection during intervals when the Moon was embedded in the Earth's magnetotail lobe. In the absence of plasma effects on the source process, ion species of H+, He++, He+, C+, O+, Na+, K+ and Ar+ are definitively identified. The ion fluxes were higher when the solar zenith angle was smaller, which is consistent with the idea that the solar photon driven processes dominates in supplying exospheric components.
How strong are the Southern Hemisphere storm tracks?
Authors: Guo Yanjuan , Chang Edmund K. M. , Leroy Stephen S.
Published: November 2009

The real strength of the Southern Hemisphere (SH) storm tracks is poorly known, as the NCEP‐NCAR and ECMWF reanalyses differ significantly in this measure. In this work, the COSMIC GPS radio occultation dataset is used to investigate this issue. The ratio of the strength of the SH storm tracks to that in the Northern Hemisphere (NH) based on the COSMIC dataset can be regarded as close to the true inter‐hemisphere ratio since the dataset has similar biases and errors in both hemispheres. Comparing this ratio with that based on the reanalysis, it is found that the strength of the SH storm tracks in the NCEP‐NCAR reanalysis is significantly biased low by at least 25% at 300 hPa, while those in the ECMWF reanalyses are much closer to that inferred from COSMIC observations but ERA40 may be biased low by 5–10%.
Fluvial network analysis on Titan: Evidence for subsurface structures and west‐to‐east wind flow, southwestern Xanadu
Authors: Burr Devon M. , Jacobsen Robert E. , Roth Danica L. , Phillips Cynthia B. , Mitchell Karl L. , Viola Donna
Published: November 2009

Data of Titan's surface from the Cassini‐Huygens mission show inferred fluvial networks interpreted as products of liquid alkane flow. Using synthetic aperture radar (SAR) data, we delineated drainage networks, measured network parameters, and used these measurements in a simplified algorithm for classifying terrestrial drainage patterns. The results show a variety of patterns, indicating that a variety of factors control fluvial drainage on Titan. Drainage network patterns in southwestern Xanadu are classified as rectangular, suggesting control by a subsurface tectonic structural fabric. Link orientations also suggest that this subsurface tectonic fabric is oriented predominantly east‐west. Spatial variations in drainage networks are consistent with a west‐to‐east precipitation pattern, supporting inferences from aeolian dune morphology. These results illustrate how fluvial landform analysis can yield new information on both atmospheric and subsurface processes.
A re‐evaluation of the coherence between global‐average atmospheric CO2 and temperatures at interannual time scales
Authors: Park Jeffrey
Published: November 2009

Frequency‐dependent coherence between atmospheric CO2 and historical temperatures reveals climate feedbacks within Earth's carbon cycle. Coherence between interannual fluctuations in global‐average temperature and atmospheric CO2 has changed over time. Since 1979, at Mauna Loa and other observation sites, interannual coherence exhibits a 90° phase lag that suggests a direct correlation between temperatures and the time‐derivative of CO2. The coherence transition can be explained if the response time of CO2 to a global temperature fluctuation has lengthened from 6 months to at least 15 months. A longer response time may reflect saturation of the oceanic carbon sink, but a transient shift in ocean circulation may play a role. Coherent annual‐cycle fluctuations in CO2 and temperature are evident in the 1958–1988 time series, but not since 1979. Coherence of interannual CO2 variations with gridpoint temperature anomalies are strongest in the tropical oceans.
Evaluation of flow rate for a one‐dimensional lava flow with power‐law rheology
Authors: Piombo Antonello , Dragoni Michele
Published: November 2009

During the emplacement lava behaves as a non‐Newtonian, pseudoplastic fluid. Laboratory experiments on lava samples suggest that a power‐law constitutive equation may be appropriate. We consider a horizontally unbounded, isothermal layer of lava, flowing down a slope driven by the gravity force. We consider a constitutive equation where shear stress is proportional to strain rate raised to a power n, ranging from 0 to 1, and we take into account the temperature dependence of the rheological parameters. Formulae are obtained relating the lava rheology to the geometric and dynamic parameters of a lava flow. Under the model assumptions, if we know the temperature dependence of the rheological parameters, these formulae allow to evaluate the flow rate from the field measurements of the temperature, and the thickness or the surface velocity of a lava flow.
Reformation of an oblique shock observed by Cluster
Authors: Lefebvre B. , Seki Y. , Schwartz S. J. , Mazelle C. , Lucek E. A.
Published: November 2009

On 16 March 2005, the Cluster spacecraft crossed a shock almost at the transition between the quasi‐perpendicular and quasi‐parallel regimes (θBn = 46°) preceded by an upstream low‐frequency (≈0.02 Hz in the spacecraft frame) wave train observed for more than 10 mn. The wave semicycle nearest to the shock was found to grow in time, steepen and reflect an increasing fraction of the incoming ions. This gives strong indication that this pulsation is becoming a new shock front, standing ∼5λp upstream of the main front and growing to shock‐like amplitude on a timescale of ∼ 35Ωp. Downstream of the main shock transition, remnants of an older front are found indicating that the reformation is cyclic. This provides a unique example where the dynamics of shock reformation can be sequentially followed. The process shares many characteristics with simulations of reforming quasi‐parallel shocks.
Asymmetric magnetic reconnection in the presence of a guide field
Authors: Pritchett P. L. , Mozer F. S.
Published: November 2009

The properties of asymmetric magnetic reconnection in the presence of a guide magnetic field are investigated using two‐dimensional particle‐in‐cell simulations. The reconnection process is initiated by applying a spatially localized and temporally steady convection electric field at the high‐density/low‐magnetic‐field (magnetosheath) side of the current layer. The in‐plane Hall currents are dominated by the electron flows along the separatrices from the high‐density to low‐density side of the layer, and they strongly enhance the out‐of‐plane magnetic field in one hemisphere and decrease it in the other. On the enhanced magnetic field side are situated a bipolar pair of parallel electric fields and an electron velocity shear flow layer, both of which extend several ion inertia lengths (di) away from the X line. The shear flow layer is unstable to the generation of small‐scale (≪di) electron vortices which propagate away from the X line and produce a reduction of the order of 30% in the magnitude of the By field. An example of such a large‐amplitude, short‐duration depression in By is identified in a magnetopause crossing by the THEMIS spacecraft. The Ohm's law (E + Ue × B/c)y = 0 is violated in this parallel field/velocity shear region, and the deviation arises predominantly from the divergence of the electron pressure tensor. Criteria based on the demagnetization of the electrons (large values of the electron agyrotropy and the Lorentz ratio) are found to characterize neither the immediate electron scale region around the X line nor the larger electron shear flow region.
Probing into regional ozone and particulate matter pollution in the United States: 1. A 1 year CMAQ simulation and evaluation using surface and satellite data
Authors: Zhang Yang , Vijayaraghavan Krish , Wen Xin‐Yu , Snell Hilary E. , Jacobson Mark Z.
Published: November 2009

As part 1 in a series of papers describing long‐term simulations using the Community Multiscale Air Quality (CMAQ) modeling system and subsequent process analyses and sensitivity simulations, this paper presents a comprehensive model evaluation for the full year of 2001 over the continental U.S. using both ground‐based and satellite measurements. CMAQ is assessed for its ability to reproduce concentrations and long‐term trends of major criteria pollutants such as surface ozone (O3) and fine particulate matter (PM2.5) and related variables such as indicator species, wet deposition fluxes, and column mass abundances of carbon monoxide (CO), nitrogen oxides (NO2), tropospheric ozone residuals (TORs), and aerosol optical depths (AODs). The domain‐wide and site‐specific evaluation of surface predictions shows an overall satisfactory performance in terms of normalized mean biases for annual mean maximum 1 h and 8 h average O3 mixing ratios (−11.6 to 0.1% and −4.6 to 3.0%, respectively), 24 h average concentrations of PM2.5 (4.2–35.3%), sulfate (−13.0 to 43.5%), and organic carbon (OC) (−37.6 to 24.8%), and wet deposition fluxes (−13.3 to 31.6%). Larger biases, however, occur in the concentrations and wet deposition fluxes of ammonium and nitrate domain‐wide and in the concentrations of PM2.5, sulfate, black carbon, and OC at some urban/suburban sites. The reasons for such model biases may be errors in emissions, chemistry, aerosol processes, or meteorology. The evaluation of column mass predictions shows a good model performance in capturing the seasonal variations and magnitudes of column CO and NO2, but relatively poor performance in reproducing observed spatial distributions and magnitudes of TORs for winter and spring and those of AODs in all seasons. Possible reasons for the poor column predictions include the underestimates of emissions, inaccurate upper layer boundary conditions, lack of model treatments of sea salt and dust, and limitations and uncertainties in satellite data.
Extinction layer detected by the 2003 star occultation on Pluto
Authors: Rannou P. , Durry G.
Published: November 2009

A star occultation by Pluto was monitored in August 2003 by several telescopes, at several wavelengths between 0.7μm and 2.23μm. Besides information concerning pressure and temperature profiles, this observation revealed a chromatic effect in the light transmitted through the atmosphere at the limb. It was attributed to an extinction layer produced by spherical particles of about 0.2 μm, and it was suggested that such large particle size may be due to fractal particles as on Titan. In this paper, we use an aerosol microphysical model to estimate if such extinction could be due to photochemical aerosols only. We use the case of Titan to scale the haze production rate on Pluto and we show that the chromatic effect is not likely to be produced in this way. We then study how a troposphere in Pluto's atmosphere could generate condensation droplets. We conclude that such an extinction layer is produced by condensation droplets that potentially could grow as large as observed. We find that only N2 and CO are able to condense easily. CH4 probably does not condense or, if it does, it needs to reach a very high saturation ratio and, in any case, is supersaturated on Pluto. Noteworthily, a similar layer was observed on Triton by Voyager. Finally, at the end of the paper we discuss which are the conditions to detect a chromatic effect for submicrometer to micrometer particles in future observations.
A regulating role of the JAK2 FERM domain in hyperactivation of JAK2(V617F)
Authors: Zhao Lequn , Ma Yue , Seemann Joachim , Huang Lily Jun-shen
Published: November 2009

JAK2 (Janus tyrosine kinase 2) is important for signalling through many cytokine receptors, and a gain-of-function JAK2 mutation in its pseudokinase domain, V617F, has been implicated in Philadelphia chromosome-negative myeloproliferative neoplasms. How this mutation hyperactivates JAK2 is poorly understood. In the present paper we report our findings that the V617F mutation has little effect on the Vmax of JAK2 kinase activity, but lowers the Km value for substrates. Therefore under physiological conditions where the concentration level of substrates is presumably below saturation, JAK2(V617F) exhibits hyperactivation compared with wild-type JAK2. This lower Km of JAK2(V617F) towards substrates requires the JAK2 FERM (4.1/ezrin/radixin/moesin) domain, as deletion of the FERM domain abolished this effect. We also show that, in contrast with its positive role in JAK2(V617F) hyperactivation, the FERM domain in wild-type JAK2 is inhibitory. Deletion or mutations of the FERM domain resulted in increased basal JAK2 kinase activity. The results of the present study provide the biochemical basis for how V617F hyperactivates JAK2, and identifies novel regulating roles of the JAK2 FERM domain to control kinase activity at different activation states.
Biochemical characterization, membrane association and identification of amino acids essential for the function of Alg11 from Saccharomyces cerevisiae, an α1,2-mannosyltransferase catalysing two sequential glycosylation steps in the formation of the lipid-linked core oligosaccharide
Authors: Absmanner Birgit , Schmeiser Verena , Kämpf Michael , Lehle Ludwig
Published: November 2009

The biosynthesis of asparagine-linked glycans occurs in an evolutionarily conserved manner with the assembly of the unique lipid-linked oligosaccharide precursor Glc3Man9GlcNAc2-PP-Dol at the ER (endoplasmic reticulum). In the present study we characterize Alg11 from yeast as a mannosyltransferase catalysing the sequential transfer of two α1,2-linked mannose residues from GDP-mannose to Man3GlcNAc2-PP-Dol and subsequently to Man4GlcNAc2-PP-Dol forming the Man5GlcNAc2-PP-Dol intermediate at the cytosolic side of the ER before flipping to the luminal side. Alg11 is predicted to contain three hydrophobic transmembrane-spanning helices. Using Alg11 topology reporter fusion constructs, we show that only the N-terminal domain fulfils this criterion. Surprisingly, this domain can be deleted without disturbing glycosyltransferase function and membrane association, indicating also that the other two hydrophobic domains contribute to ER localization, but in a non-transmembrane manner. By site-directed mutagenesis we investigated amino acids important for transferase activity. We demonstrate that the first glutamate residue in the EX7E motif, conserved in a variety of glycosyltransferases, is more critical than the second, and loss of Alg11 function occurs only when both glutamate residues are exchanged, or when the mutation of the first glutamate residue is combined with replacement of another amino acid in the motif. This indicates that perturbations in EX7E are not restricted to the second glutamate residue. Moreover, Gly85 and Gly87, within a glycine-rich domain as part of a potential flexible loop, were found to be required for Alg11 function. Similarly, a conserved lysine residue, Lys319, was identified as being important for activity, which could be involved in the binding of the phosphate of the glycosyl donor.
PKCδ regulates cortical radial migration by stabilizing the Cdk5 activator p35
Authors: Zhao Chun-tao , Li Kun , Li Jun-tao , Zheng Wang , Liang Xu-jun , Geng An-qi , Li Ning , Yuan Xiao-bing
Published: November 2009

Cyclin-dependent kinase 5 (Cdk5) and its activator p35 are critical for radial migration and lamination of cortical neurons. However, how this kinase is regulated by extracellular and intracellular signals during cortical morphogenesis remains unclear. Here, we show that PKCδ, a member of novel PKC expressing in cortical neurons, could stabilize p35 by direct phosphorylation. PKCδ attenuated the degradation of p35 but not its mutant derivative, which could not be phosphorylated by PKCδ. Down-regulation of PKCδ by in utero electroporation of specific small interference RNA (siRNA) severely impaired the radial migration of cortical neurons. This migration defect was similar to that caused by down-regulation of p35 and could be prevented by cotransfection with the wild-type but not the mutant p35. Furthermore, PKCδ could be activated by the promigratory factor brain-derived neurotrophic factor (BDNF) and was required for the activation of Cdk5 by BDNF. Both PKCδ and p35 were required for the promigratory effect of BDNF on cultured newborn neurons. Thus, PKCδ may promote cortical radial migration through maintaining the proper level of p35 in newborn neurons.
A distinctive role of the leukotriene B
4
receptor BLT1 in osteoclastic activity during bone loss
Authors: Hikiji Hisako , Ishii Satoshi , Yokomizo Takehiko , Takato Tsuyoshi , Shimizu Takao
Published: November 2009

Although leukotriene B
4
(LTB
4
) is produced in various inflammatory diseases, its functions in bone metabolism remain unknown. Using mice deficient in the high-affinity LTB
4
receptor BLT1, we evaluated the roles of BLT1 in the development of two bone resorption models, namely bone loss induced by ovariectomy and lipopolysaccharide. Through observations of bone mineral contents and bone morphometric parameters, we found that bone resorption in both models was significantly attenuated in BLT1-deficient mice. Furthermore, osteoclasts from BLT1-deficient mice showed reduced calcium resorption activities compared with wild-type osteoclasts. Osteoclasts expressed BLT1, but not the low-affinity LTB
4
receptor BLT2, and produced LTB
4
. LTB
4
changed the cell morphology of osteoclasts through the BLT1-Gi protein-Rac1 signaling pathway. Given the causal relationship between osteoclast morphology and osteoclastic activity, these findings suggest that autocrine/paracrine LTB
4
increases the osteoclastic activity through the BLT1-Gi protein-Rac1 signaling pathway. Inhibition of BLT1 functions may represent a strategy for preventing bone resorption diseases.
The regulatory mechanism of Hsp90α secretion and its function in tumor malignancy
Authors: Wang Xiaofeng , Song Xiaomin , Zhuo Wei , Fu Yan , Shi Hubing , Liang Yun , Tong Maomeng , Chang Guodong , Luo Yongzhang
Published: November 2009

Heat shock protein 90-α (Hsp90α) is an intracellular molecular chaperone. However, it can also be secreted with the underlying regulatory mechanism remaining far from clear. Here we show that the secreted Hsp90α is a C-terminal truncated form and its secretion is regulated by the C-terminal EEVD motif via interacting with proteins containing tetratricopeptide repeat domains. We also demonstrate that secretion of Hsp90α is determined by the phosphorylation status at residue Thr-90, regulated by protein kinase A and protein phosphatase 5. We further demonstrate that the secretion of Hsp90α is a prerequisite for its proinvasiveness function and blocking the secreted Hsp90α results in significant inhibition of tumor metastasis. Meanwhile, the level of plasma Hsp90α is positively correlated with tumor malignancy in clinical cancer patients. In sum, our results reveal the regulatory mechanism of Hsp90α secretion, and its function in tumor invasiveness, indicating it can be a promising diagnostic marker for tumor malignancy in clinical application.
MicroRNAs couple cell fate and developmental timing in retina
Authors: Decembrini Sarah , Bressan Dario , Vignali Robert , Pitto Letizia , Mariotti Sara , Rainaldi Giuseppe , Wang Xiumei , Evangelista Monica , Barsacchi Giuseppina , Cremisi Federico
Published: November 2009

Cell identity is acquired in different brain structures according to a stereotyped timing schedule, by accommodating the proliferation of multipotent progenitor cells and the generation of distinct types of mature nerve cells at precise times. However, the molecular mechanisms coupling the identity of a specific neuron and its birth date are poorly understood. In the neural retina, only late progenitor cells that divide slowly can become bipolar neurons, by the activation ofotx2andvsx1genes. InXenopus, we found thatXotx2andXvsx1translation is inhibited in early progenitor cells that divide rapidly by a set of cell cycle-related microRNAs (miRNAs). Through expression and functional screenings, we selected 4 miRNAs—mir-129, mir-155, mir-214, and mir-222—that are highly expressed at early developmental stages in the embryonic retina and bind to the 3′ UTR ofXotx2andXvsx1mRNAs inhibiting their translation. The functional inactivation of these miRNAs in vivo releases the inhibition, supporting the generation of additional bipolar cells. We propose a model in which the proliferation rate and the age of a retinal progenitor are linked to each other and determine the progenitor fate through the activity of a set of miRNAs.
Studies on expression and function of the TMEM16A calcium-activated chloride channel
Authors: Huang Fen , Rock Jason R. , Harfe Brian D. , Cheng Tong , Huang Xiaozhu , Jan Yuh Nung , Jan Lily Yeh
Published: November 2009

Calcium-activated chloride channels (CaCC) with similar hallmark features are present in many cell types and mediate important physiological functions including epithelial secretion, sensory signal transduction, and smooth muscle contraction. Having identified TMEM16A of the transmembrane proteins with unknown function (TMEM) 16 family as a CaCC subunit, we have developed antibodies specific for mouse TMEM16A, as evidenced by the absence of immunoreactivity in TMEM16A knockout mice. Here, we show that TMEM16A is located in the apical membranes of epithelial cells in exocrine glands and trachea. In addition, TMEM16A is expressed in airway smooth muscle cells and the smooth muscle cells of reproductive tracts, the oviduct and ductus epididymis. In the gastrointestinal (GI) tract, TMEM16A is absent from smooth muscle cells, but present in the interstitial cells of Cajal (ICC), the pacemaker cells that control smooth muscle contraction. The physiological importance of TMEM16A is underscored by the diminished rhythmic contraction of gastric smooth muscle from TMEM16A knockout mice. The TMEM16A expression pattern established in this study thus provides a roadmap for the analyses of physiological functions of calcium-activated chloride channels that contain TMEM16A subunits.
The appearance of pyrrolysine in tRNA
His
guanylyltransferase by neutral evolution
Authors: Heinemann Ilka U. , O'Donoghue Patrick , Madinger Catherine , Benner Jack , Randau Lennart , Noren Christopher J. , Söll Dieter
Published: November 2009

tRNA
His
guanylyltransferase (Thg1) post-transcriptionally adds a G (position −1) to the 5′-terminus of tRNA
His
. The
Methanosarcina acetivorans
Thg1 (MaThg1) gene contains an in-frame TAG (amber) codon. Although a UAG codon typically directs translation termination, its presence in
Methanosarcina
mRNA may lead to pyrrolysine (Pyl) incorporation achieved by Pyl-tRNA
Pyl
, the product of pyrrolysyl-tRNA synthetase. Sequencing of the MaThg1 gene and transcript confirmed the amber codon. Translation of MaThg1 mRNA led to a full-length, Pyl-containing, active enzyme as determined by immunoblotting, mass spectrometry, and biochemical analysis. The nature of the inserted amino acid at the position specified by UAG is not critical, as Pyl or Trp insertion yields active MaThg1 variants in
M. acetivorans
and equal amounts of full-length protein. These data suggest that Pyl insertion is akin to natural suppression and unlike the active stop codon reassignment that is required for selenocysteine insertion. Only three Pyl-containing proteins have been characterized previously, a set of methylamine methyltransferases in which Pyl is assumed to have specifically evolved to be a key active-site constituent. In contrast, Pyl in MaThg1 is a dispensable residue that appears to confer no selective advantage. Phylogenetic analysis suggests that Thg1 is becoming dispensable in the archaea, and furthermore supports the hypothesis that Pyl appeared in MaThg1 as the result of neutral evolution. This indicates that even the most unusual amino acid can play an ordinary role in proteins.
True and false memory for colour names versus actual colours: Support for the visual distinctiveness heuristic in memory for colour information
Authors: Eslick Andrea N. , Kostic Bogdan , Cleary Anne M.
Published: November 2009

In a colour variation of the Deese–Roediger–McDermott (DRM) false memory paradigm, participants studied lists of words critically related to a nonstudied colour name (e.g., “blood, cherry, scarlet, rouge … ”); they later showed false memory for the critical colour name (e.g., “red”). Two additional experiments suggest that participants generate colour imagery in response to such colour-related DRM lists. First, participants claim to experience colour imagery more often following colour-related than standard non-colour-related DRM lists; they also rate their colour imagery as more vivid following colour-related lists. Second, participants exhibit facilitative priming for critical colours in a dot selection task that follows words in the colour-related DRM list, suggesting that colour-related DRM lists prime participants for the actual critical colours themselves. Despite these findings, false memory for critical colour names does not extend to the actual colours themselves (font colours). Rather than leading to source confusion about which colours were self-generated and which were studied, presenting the study lists in varied font colours actually worked to reduce false memory overall. Results are interpreted within the framework of the visual distinctiveness hypothesis.
A method for defining management units based on genetically determined close relatives
Authors: Økland Jan-Magnus , Haaland Øystein Ariansen , Skaug Hans J.
Published: November 2009

Økland, J-M., Haaland, Ø. A., and Skaug, H. J. 2010. A method for defining management units based on genetically determined close relatives. – ICES Journal of Marine Science, 67: 551–558. We propose a new method for identifying management units from genetic samples (DNA profiles). The main idea is to look at the geographic distribution of genetically determined close relatives and to use these to separate different breeding populations. The method has the potential to detect population structure emerging on a demographic time-scale, as opposed to classical population genetic methods. It is not required that the breeding populations have different allele frequencies. Using simulated datasets, the proposed method has good statistical properties throughout the range of migration rates considered. This may be a powerful method for setting management boundaries.
Artifact on Electromyography Produced by an Implanted Sacral Nerve Stimulator
Authors: O'Carroll Peter , Bertorini Tulio E , Maccarino Sue
Published: November 2009

A patient with muscle cramps was referred for nerve conduction studies and electromyography. Her study demonstrated bursts of spontaneous electromyography activity, which waxed and waned in amplitude with a “dive bomber”-like sound. The abnormal finding was found to be an artifact from an implanted sacral nerve stimulator for bladder incontinence.
Ageing and thermal performance in the sub-Antarctic wingless flyAnatalanta aptera(Diptera: Sphaeroceridae): older is better
Authors: Lalouette L. , Vernon P. , Amat H. , Renault D.
Published: November 2009

Senescence is a progressive biological process expressed in behavioural, morphological, physiological, biochemical and cellular age-related changes. Age-associated alterations in activity are regularly found in insects when examining whole-organism senescence over the adult lifespan. In addition, overall stress resistance usually decreases with senescence. In the present study, we measured the critical thermal minimum (CTmin) and the subsequent recovery period over the lifespan of the sub-Antarctic wingless fly,Anatalanta aptera. Experiments were conducted on males and females in seven age groups: newly emerged, 1.5-, 5-, 7-, 13-, 15- and 18-month-old adults. Surprisingly, CTmindecreased significantly with ageing inA. aptera, from −3.8 ± 0.5°C just after the emergence to −5.6 ± 0.7°C in the 18-month-old flies. The subsequent recovery period remained similar between the seven groups tested. Our unexpected results contradict the previous data collected in other insects. We have demonstrated for the first time that ageing may improve rather than impair locomotor activity during unfavourable thermal conditions. It raises questions and challenges the literature dealing with ageing. These fascinating results also question the underpinning mechanisms involved in the improvement of the thermal performance with ageing inA. aptera.
Adhaeribacter aerophilus sp. nov., Adhaeribacter aerolatus sp. nov. and Segetibacter aerophilus sp. nov., isolated from air samples
Authors: Weon Hang-Yeon , Kwon Soon-Wo , Son Jung-A , Kim Soo-Jin , Kim Yi-Seul , Kim Byung-Yong , Ka Jong-Ok
Published: November 2009

Three bacterial isolates from air samples in Korea, designated strains 6424S-25T, 6515J-31T and 6424S-61T, were characterized using a polyphasic approach. The cells were strictly aerobic, Gram-stain-negative, non-motile, non-spore-forming and rod-shaped. Phylogenetic analysis of their 16S rRNA gene sequences revealed a clear affiliation with the phylum Bacteroidetes. Strains 6424S-25T and 6515J-31T showed 16S rRNA gene sequence similarities of 92.7–94.8 % to type strains of recognized species of the genus Adhaeribacter and strain 6424S-61T was closely related to Segetibacter koreensis Gsoil 664T (93.9 % similarity). The G+C contents of the DNA of strains 6424S-25T, 6515J-31T and 6424S-61T were 44.5, 43.9 and 38.4 mol%, respectively. Major fatty acids of strains 6424S-25T and 6515J-31T were summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B), iso-C15 : 0 and C16 : 1
ω5c. The fatty acid content of strain 6424S-61T mainly comprised iso-C15 : 1 G and iso-C15 : 0. Comparative analysis of phenotypic and phylogenetic traits indicated that strains 6424S-25T and 6515J-31T represented two novel species of the genus Adhaeribacter and that strain 6424S-61T should be considered as a novel species of the genus Segetibacter. The names Adhaeribacter aerophilus sp. nov. (type strain 6424S-25T =KACC 14118T =NBRC 106134T), Adhaeribacter aerolatus sp. nov. (type strain 6515J-31T =KACC 14117T =NBRC 106133T) and Segetibacter aerophilus sp. nov. (type strain 6424S-61T =KACC 14119T =NBRC 106135T) are proposed for these organisms.
The WRKY6 Transcription Factor ModulatesPHOSPHATE1Expression in Response to Low Pi Stress inArabidopsis
Authors: Chen Yi-Fang , Li Li-Qin , Xu Qian , Kong You-Han , Wang Hui , Wu Wei-Hua
Published: November 2009

Arabidopsis thaliana WRKY family comprises 74 members and some of them are involved in plant responses to biotic and abiotic stresses. This study demonstrated that WRKY6 is involved in Arabidopsis responses to low-Pi stress through regulating PHOSPHATE1 (PHO1) expression. WRKY6 overexpression lines, similar to the pho1 mutant, were more sensitive to low Pi stress and had lower Pi contents in shoots compared with wild-type seedlings and the wrky6-1 mutant. Immunoprecipitation assays demonstrated that WRKY6 can bind to two W-boxes of the PHO1 promoter. RNA gel blot and β-glucuronidase activity assays showed that PHO1 expression was repressed in WRKY6-overexpressing lines and enhanced in the wrky6-1 mutant. Low Pi treatment reduced WRKY6 binding to the PHO1 promoter, which indicates that PHO1 regulation by WRKY6 is Pi dependent and that low Pi treatment may release inhibition of PHO1 expression. Protein gel blot analysis showed that the decrease in WRKY6 protein induced by low Pi treatment was inhibited by a 26S proteosome inhibitor, MG132, suggesting that low Pi–induced release of PHO1 repression may result from 26S proteosome–mediated proteolysis. In addition, WRKY42 also showed binding to W-boxes of the PHO1 promoter and repressed PHO1 expression. Our results demonstrate that WRKY6 and WRKY42 are involved in Arabidopsis responses to low Pi stress by regulation of PHO1 expression.
Inequality and the self‐selection of international migrants: theory and new evidence
Authors: Brücker Herbert , Defoort Cécily
Published: November 2009

Purpose

The paper seeks to analyse the self‐selection of international migrants on observable skills.

Design/methodology/approach

Based on an extended version of the Roy model, which considers random migration costs, the authors analyse the self‐selection of migrants on observable skills empirically. For this purpose, the authors employ a new panel data set on the educational attainment of migrants, which covers migration from 143 sending countries into the six main receiving countries in the OECD from 1975 to 2000.

Findings

Migrants tend to be positively self‐selected on observable skills, although the inequality in earnings is larger in the sending country relative to the destination countries. The estimation results indicate that a higher inequality in the distribution of earnings in both the receiving and the sending country affects the skill bias of the migrant population favourably. Moreover, higher migration costs and selective immigration policies increase the skill level of migrants relative to those of stayers in the sending countries.

Research limitations/implications

The results may be affected by measurement error, since it was necessary to approximate the returns to education by measures for the inequality of earnings.

Practical implications

The paper provides, inter alia, insights as to how immigration and other policies affect the self‐selection of migrants on observable skills, which may be relevant for policy makers.

Originality/value

To the authors' knowledge, this is the first paper to analyse the self‐selection of migrants on the basis of a panel data set.
Internal wage dispersion and firm performance: white‐collar evidence
Authors: Hunnes Arngrim
Published: November 2009

Purpose

The purpose of this paper is to investigate the net relationship between internal wage dispersion and firm performance.

Design/methodology/approach

An empirical investigation of the relationship between internal wage dispersion and firm performance is performed using linked employer‐employee data for Norwegian firms from 1986 to 1997.

Findings

Contrary to findings in previous empirical work of a positive relationship between internal wage dispersion and firm performance, the analysis finds no such evidence in Norwegian firms, even though internal wage dispersion has increased.

Originality/value

The paper contributes to the relatively sparse empirical literature on internal wage dispersion and firm performance. Further, the analysis provides a new econometric specification for estimating internal wage dispersion that explicitly takes into account the hierarchical organization of firms. In contrast with previous work, the analysis also distinguishes between dispersion in both the fixed and variable portions of wages.
Operations management research: contemporary themes, trends and potential future directions
Authors: Taylor Andrew , Taylor Margaret
Published: November 2009

Purpose

The purpose of this paper is to identify the contemporary research themes published in IJOPM in order to contribute to current debates about the future directions of operations management (OM) research.

Design/methodology/approach

All 310 articles published in IJOPM from volume 24 issue 9 in 2004 through volume 29, issue 12 in 2009 are analysed using content analysis methods. This period of analysis is chosen because it represents all the articles published in issues for which the authors are able to have full control, during their period of tenure as Editors of the journal. This analysis is supplemented by data on all 1,853 manuscripts submitted to the journal during the same time period and further, by analysis of reviews and feedback sent to all authors after review.

Findings

The paper reports the main research themes and research methods inherent in the 310 published papers. Statistics on the countries represented by these papers and the size and international composition of author teams are provided, together with the publication success rates of the countries that submit in the highest volumes, and the success rates associated with the size of the author team. Finally, data on the reasons for rejection of manuscripts are presented.

Research limitations/implications

There is some residual inaccuracy in content analysis methods, whereby, in extracting research themes there is often more than one topic covered. In the same vein, as regards categorisation of the causes of rejection of manuscripts during the review process, there is frequently more than one reason for rejection, so perhaps a weighted scoring system would have been more insightful. In determining the country of origin of papers, while the country of the corresponding author is used, it should be recognised that some studies originate from international collaborations so that this method may give a slightly distorted picture. Finally, in computing publication success rates by comparison of submissions and published papers there is a time delay between the two data sets within any defined period of analysis.

Practical implications

The analysis adds generally to debates about contemporary research themes; in particular it extends the work of Pilkington and Fitzgerald, which analyses all articles solely in IJOPM between 1994 and 2003. In addition, the findings suggest a need for more frequent exploitation of multiple research methods, for greater rigour in the planning and execution of fieldwork, for greater engagement with the world of OM practice and finally, consideration of how OM research can address wider social and political issues.

Originality/value

This paper represents an inside view of the publication process from a leading OM journal; this kind of insight is rarely available in the public domain.
Knowledge management audit framework and methodology based on processes
Authors: Wang Jiankang , Xiao Jiuling
Published: November 2009

Purpose

The purpose of this paper is to analyze the detailed content and research framework of a knowledge management audit, from the view of operation flow based on a cognition summary of knowledge management audit proposed by many scholars and organizations, in order to put forward some references for effective implementation of an organization knowledge management project.

Design/methodology/approach

The paper carries out a multi‐perspective analysis of the cognition of knowledge management audit summarizes the similarities and differences between the different viewpoints, also a contrasting analysis on the method proposed by various scholars and organizations from the point of view of flow, and then constructs the conceptive framework of knowledge management audit.

Findings

Knowledge management audit is the first important step in a knowledge management project and includes four phases: preparation, analysis, implementation, and summary. Its primary content involves knowledge management environment audit, knowledge property audit, knowledge management ability audit and knowledge management performance audit, and its main modules consist of knowledge demand analysis, knowledge inventory analysis, knowledge map and knowledge flow analysis.

Research limitations/implications

The paper provides a theoretical construction, but has not conducted a case study. In future research development, the framework of the paper will be improved through the case analysis of organization knowledge management practice.

Practical implications

By utilizing the research framework and method of the paper, an organization may understand rapidly the basic content of a knowledge management audit, implement an effective knowledge management audit to help improve organization (including non‐profit organization) performance and implement a knowledge management strategy.

Originality/value

The paper provides a framework for implementing a knowledge management audit.