bluuebunny/crossref_metadata_2025 huggingface dataset:
Upscaled CTAB-Based DNA Extraction and Real-Time PCR Assays for Fusarium culmorum and F. graminearum DNA in Plant Material with Reduced Sampling Error
Authors: Brandfass Christoph , Karlovsky Petr
Published: November 2008

Fusarium graminearum Schwabe (Gibberella zeae Schwein. Petch.) and F. culmorum W.G. Smith are major mycotoxin producers in small-grain cereals afflicted with Fusarium head blight (FHB). Real-time PCR (qPCR) is the method of choice for species-specific, quantitative estimation of fungal biomass in plant tissue. We demonstrated that increasing the amount of plant material used for DNA extraction to 0.5-1.0 g considerably reduced sampling error and improved the reproducibility of DNA yield. The costs of DNA extraction at different scales and with different methods (commercial kits versus cetyltrimethylammonium bromide-based protocol) and qPCR systems (doubly labeled hybridization probes versus SYBR Green) were compared. A cost-effective protocol for the quantification of F. graminearum and F. culmorum DNA in wheat grain and maize stalk debris based on DNA extraction from 0.5-1.0 g material and real-time PCR with SYBR Green fluorescence detection was developed.
Pattern Recognition via PCNN and Tsallis Entropy
Authors: Zhang YuDong , Wu LeNan
Published: November 2008

In this paper a novel feature extraction method for image processing via PCNN and Tsallis entropy is presented. We describe the mathematical model of the PCNN and the basic concept of Tsallis entropy in order to find a recognition method for isolated objects. Experiments show that the novel feature is translation and scale independent, while rotation independence is a bit weak at diagonal angles of 45° and 135°. Parameters of the application on face recognition are acquired by bacterial chemotaxis optimization (BCO), and the highest classification rate is 72.5%, which demonstrates its acceptable performance and potential value.
Fabricación de soportes anódicos metálicos para SOFC por vía pulvimetalúrgica
Authors: Arahuetes E. , Bautista A. , Velasco F. , Sotomayor M. E.
Published: November 2008

La comercialización de tecnologías de producción de energía medioambientalmente respetuosas, como las pilas de óxido sólido (SOFC), implica el abaratamiento de los materiales con que han sido, inicialmente, diseñadas. El empleo de un soporte metálico poroso que reduzca significativamente la cantidad de material cerámico activo es una opción muy interesante. En este trabajo se estudia el procesado de 4 aleaciones diferentes (dos base Fe y dos base Ni) para su posible utilización como soportes metálicos porosos en SOFC. Se propone un sistema ligante que, mezclado con polvos metálicos de gran tamaño, permita obtener materiales con el nivel de porosidad requerida (≥ 30 %). Además, la realización de una etapa de granulado previa a la compactación de las mezclas de polvo metálico permite fabricar piezas que mantienen, pese a su elevada porosidad, la estabilidad dimensional durante el proceso de eliminación del ligante.
Influencia de los tratamientos realizados con diferentes ferroaleaciones de magnesio en la evolución de la calidad metalúrgica y los procesos de solidificación de las fundiciones esferoidales
Authors: Loizaga A. , Sertucha J. , Suárez R.
Published: November 2008

En el presente trabajo se analizan las implicaciones metalúrgicas de efectuar tratamientos con ferroaleaciones de diferente contenido de magnesio para fabricar fundición esferoidal. Los procesos de solidificación del hierro son los responsables de las propiedades mecánicas y la funcionalidad de las piezas en su etapa de servicio. Por esta razón, la comparación de las características de las curvas de solidificación del metal y sus contenidos de oxígeno activo y azufre se han utilizado para cuantificar los efectos de los tratamientos realizados con distintas ferroaleaciones de magnesio comerciales. La adición de magnesio en el metal fundido supone la aparición de fuertes reacciones de desoxidación y desulfuración, por lo que la calidad del hierro tratado sufre degradaciones, que perjudican las características metalúrgicas del material. Por otra parte, se investiga la naturaleza de las escorias formadas y la evolución de las características del metal durante el tiempo de permanencia de éste en el dispositivo de colada. El contenido de magnesio en las ferroaleaciones es un parámetro que ha mostrado una importante influencia en la evolución de la calidad del metal tras finalizar el proceso de tratamiento.
Extracción electroquímica de carburos de microaleación en Nb-acero
Authors: Rivas A. L. , Vidal E. , Matlock D. K. , Speer J. G.
Published: November 2008

La técnica de extracción electroquímica fue empleada para evaluar su efectividad en la caracterización de precipitados en aceros microaleados. Para realizar el estudio, se utilizó un acero SAE 8620 modificado con niobio. La investigación se llevó a cabo variando la composición del electrolito utilizado en la disolución electroquímica de la matriz y el tamaño de poro de los filtros usados para recolectar las partículas precipitadas. La cuantificación del contenido de Nb se hizo por espectroscopia de emisión atómica de plasma (ICP-AES). Además, las muestras obtenidas por réplicas de extracción y las provenientes de los residuos recolectados en los filtros fueron analizadas mediante microscopía electrónica de transmisión. Estas últimas muestras, también fueron caracterizadas por difracción de rayos X. Los resultados mostraron que la velocidad de disolución electroquímica de las muestras es mayor en el electrolito acuoso con 10 vol. % HCl. Adicionalmente, el análisis mediante microscopía electrónica de transmisión, en combinación con los análisis químicos mediante ICP-AES, mostró que las partículas de (Nb,Ti)C son recolectadas en filtros de acetato con tamaños de poro mucho mayor que el tamaño de las partículas precipitadas.
Preferential Interface Nucleation: An Expansion of the VLS Growth Mechanism for Nanowires
Authors: Wacaser Brent A. , Dick Kimberly A. , Johansson Jonas , Borgström Magnus T. , Deppert Knut , Samuelson Lars
Published: November 2008

A review and expansion of the fundamental processes of the vapor–liquid–solid (VLS) growth mechanism for nanowires is presented. Although the focus is on nanowires, most of the concepts may be applicable to whiskers, nanotubes, and other unidirectional growth. Important concepts in the VLS mechanism such as preferred deposition, supersaturation, and nucleation are examined. Nanowire growth is feasible using a wide range of apparatuses, material systems, and growth conditions. For nanowire growth the unidirectional growth rate must be much higher than growth rates of other surfaces and interfaces. It is concluded that a general, system independent mechanism should describe why nanowires grow faster than the surrounding surfaces. This mechanism is based on preferential nucleation at the interface between a mediating material called the collector and a crystalline solid. The growth conditions used mean the probability of nucleation is low on most of the surfaces and interfaces. Nucleation at the collector‐crystal interface is however different and of special significance is the edge of the collector‐crystal interface where all three phases meet. Differences in nucleation due to different crystallographic interfaces can occur even in two phase systems. We briefly describe how these differences in nucleation may account for nanowire growth without a collector. Identifying the mechanism of nanowire growth by naming the three phases involved began with the naming of the VLS mechanism. Unfortunately this trend does not emphasize the important concepts of the mechanism and is only relevant to one three phase system. We therefore suggest the generally applicable term preferential interface nucleation as a replacement for these different names focusing on a unifying mechanism in nanowire growth.
Structure and magnetic properties of regenerated cellulose/Fe3O4 nanocomposite films
Authors: Zhou Jinping , Li Ran , Liu Shilin , Li Qian , Zhang Linzhi , Zhang Lina , Guan Jianguo
Published: November 2008

Cellulose nanocomposites containing high contents of Fe3O4 nanoparticles were successfully prepared with regenerated cellulose films as a matrix and mixture solutions of Fe2+/Fe3+ as precursors. The structure and properties of the magnetic nanocomposite films were investigated with X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and vibrating sample magnetometry. Fe3O4 nanoparticles as prepared were irregular spheres and were homogeneously dispersed in the cellulose matrix. With an increase in the concentration of precursors from 0.2 to 1.0 mol/L, the content of Fe3O4 nanoparticles in the dried nanocomposites increased from 12 to 39 wt %, and the particle diameter increased from 32 to 64 nm. The cellulose nanocomposite films demonstrated superparamagnetic behavior, and their saturation magnetizations were in the range 4.2–21.2 emu/g, which were related to the increase in Fe3O4 nanoparticle content. With increasing nanophase content, the nanocomposite films displayed significantly anisotropic magnetic properties in the parallel and perpendicular directions. This study provided a green and facile method for the preparation of biobased nanocomposite films with high nanophase content and excellent magnetic properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Modeling diameter distributions of poly(N‐isopropylacrylamide‐co‐methacrylic acid) nanoparticles
Authors: Cao Quang , Tian Peng , Wu Qinglin
Published: November 2008

The Weibull distribution was successfully used to describe the diameter distribution of poly(N‐isopropylacrylamide‐co‐methacrylic Acid (PNIPAAm‐MAA) nanoparticles, whereas the lognormal was deemed not adequate for that purpose. The method of moments was used to predict parameters of the Weibull distribution. In this approach, the Weibull parameters were recovered from the diameter mean and variance, both of which were predicted from temperature. The distributions predicted from various temperatures for both MAA/NIPAAm ratios of 0.05 and 0.10 showed trends similar to those displayed in the observed data. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Self‐cleaning, titanium dioxide based, multilayer coating fabricated on polymer and glass surfaces
Authors: Kasanen Jussi , Suvanto Mika , Pakkanen Tuula T.
Published: November 2008

A photocatalytic self‐cleaning titanium dioxide (TiO2) coating was prepared as a multilayer coating structure by the spin‐coating method. Three substrate materials (two thermoplastics and one ceramic) were used: (1) high‐density polyethylene (HDPE), (2) poly(vinyl chloride), and (3) borosilicate glass (BK7). The multilayer structure consisted of a polyurethane protective layer on the substrate, two layers of photocatalytic TiO2 on the protective layer, and finally immobilized TiO2 particles bound in a diluted polyurethane dispersion. Photocatalytically active surfaces were achieved by reactive oxygen‐plasma surface etching of the fabricated coatings. The structure and properties of the coating surfaces were characterized with scanning electron microscopy and contact‐angle measurements. The coatings on HDPE and BK7 were rendered superhydrophilic by an oxygen‐plasma treatment. The photocatalytic activity and self‐cleaning properties of the prepared surfaces were studied with palmitic acid (model soil), the degradation of which was confirmed by contact‐angle measurements and gas chromatography analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mechanical behavior of agro‐residue‐reinforced polypropylene composites
Authors: Ashori Alireza , Nourbakhsh Amir
Published: November 2008

In this research, fully environment‐friendly, sustainable and biodegradable composites were fabricated, using wheat straw and rice husk as reinforcements for thermoplastics, as an alternative to wood fibers. Mechanical properties including tensile, flexural, and impact strength properties were examined as a function of the amount of fiber and coupling agent used. In the sample preparation, three levels of fiber loading (30, 40, and 50 wt %) and two levels of coupling agent content (0 and 2 wt %) were used. As the percentage of fiber loading increased, flexural and tensile properties increased significantly. Notched Izod results showed a decrease in strength as the percentage of fiber increases. With addition of 50% fiber, the impact strengths decreased to 16.3, 14.4, and 16.4 J/m respectively, for wheat straw‐, rice husk‐, and poplar‐filled composites. In general, presence of coupling agent had a great effect on the mechanical strength properties. Wheat straw‐ and rice husk‐filled composites showed an increase in the tensile and flexural properties with the incorporation of the coupling agent. From these results, we can conclude that wheat straw and rice husk fibers can be potentially suitable raw materials for manufacturing biocomposite products. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of a polymeric membrane with a fine porous structure by dry casting
Authors: Kim Jae‐Kyung , Taki Kentaro , Nagamine Shinsuke , Ohshima Masahiro
Published: November 2008

We prepared a polymeric membrane with a fine porous structure from polystyrene (PS), poly(ethylene glycol) (PEG), and solvent solutions by exploiting the phase separation induced in the course of dry casting. To determine the effect of the drying rate and phase separation on the developed porous structure, six different solvents, including toluene, chlorobenzene, tetrahydrofuran, methyl ethyl ketone, 1,4‐dioxane, and chloroform, were used. The pore size and density drastically changed with the different solvents and drying conditions. The polymer concentration at the onset of the phase separation into PEG‐rich and PS‐rich phases also strongly affected the cellular structure. The solubility of PEG into PS and the solvent solutions changed the concentration, which corresponded to the viscosity of the PS‐rich solution at the onset of the phase separation. The higher solubility of PEG in the solutions delayed the onset of phase separation during drying and increased the viscosity. The higher viscosity and the higher drying rate prevented the phase‐separated PEG domains from coalescing and made the resulting pore size smaller and the pore density larger. The finest porous structure, with a pore size of approximately 1 μm and a pore density of 0.08 1/μm2, was prepared from PS/PEG and a 90 wt % chloroform solution. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Legislation and the capacity for rapid‐response management of nonindigenous species of fish in contiguous waters of Canada and the USA
Authors: Thomas Vernon G. , Vásárhelyi Charlotte , NIIMI Arthur J.
Published: November 2008

The provision of Canadian and US hard, enforceable, law to authorize rapid response management of nonindigenous aquatic species originating from aquaculture, live fish sales, bait fish, and the pet trade was analysed at the provincial/state levels of government for the Atlantic, Laurentian Great Lakes, and Pacific regions of North America.

No federal legal capacity for rapid response management exists in either country. US state legislation is generally better developed than Canadian provincial laws to manage the exotic fish trade. However, much discrepancy exists among provincial and state law regarding provisions to restrict or prohibit potentially harmful species. Aquaculture and baitfish use is generally better regulated than live fish markets and the pet fish trade in both countries. Only the state of Maine has laws authorizing rapid‐response management to control escaped exotic fish.

Most species of nonindigenous fish arise from the aquarium, pet, and baitfish trades, and development of improved legislation containing provisions for rapid response management of escapees is warranted in all states and provinces.

It is recommended that Canada amends the Fisheries Act to create the appropriate enabling legislation to monitor, assess risk, and deploy rapid response management of nonindigenous aquatic species, including fish that enter federal fresh and sea waters. Two recently‐introduced US Bills, S. 725 and H.R. 1350, with their explicit measures for early detection and fast action response, could, if passed into law, create provisions to control introduced nuisance species throughout North American waters. They would also create precedents for states and provinces that have most jurisdiction over aquaculture and trade in exotic fish to amend and align their laws in a complementary manner.

Copyright © 2008 John Wiley & Sons, Ltd.
The Chromaffin Vesicle: Advances in Understanding the Composition of a Versatile, Multifunctional Secretory Organelle
Authors: Crivellato Enrico , Nico Beatrice , Ribatti Domenico
Published: November 2008

Chromaffin vesicles (CV) are highly sophisticated secretory organelles synthesized in adrenal medullary chromaffin cells. They contain a complex mixture of structural proteins, catecholamine neurotransmitters, peptide hormones, and the relative processing enzymes, as well as protease inhibitors. In addition, CV store ATP, ascorbic acid, and calcium. During the last decades, extensive studies have contributed to increase our understanding of the molecular composition of CV. Yet, the recent development of biochemical and imaging procedures has greatly increased the list of CV‐soluble constituents and opened new horizons as to the complexity of CV involvement in acute stress responses. Thus, a coherent picture of CV molecular composition is still to be drawn. This review article will provide a detailed account of the content of CV soluble molecules as it emerges from the most recent analytical studies. Moreover, this review article will attempt at focussing on the physiological and pathophysiological implications of the products released by CV. Anat Rec, 291:1587–1602, 2008. © 2008 Wiley‐Liss, Inc.
Requirement of TCTG(G/C) Direct Repeats and Overlapping GATA Site for Maintaining the Cardiac‐Specific Expression of Cardiac troponin T in Developing and Adult Mice
Authors: Harlan Shannon M. , Reiter Rebecca S. , Sigmund Curt D. , Lin Jenny Li‐Chun , Lin Jim Jung‐Ching
Published: November 2008

Transgenic mouse brain shown to the right (top and bottom, dorsal and ventral views, respectively) displays an ectopic expression of LacZ transgene driven by a mutant cardiac troponin T promoter, which contains a 2‐bp substitution destroying the critical TCTG(G/C) direct repeats. In contrast, the wild type promoter drives LacZ transgene specifically in the heart (not shown) but not ectopically in the brain shown to the left (top and bottom, dorsal and ventral views, respectively). See Harlan et al., on page 1574, in this issue.
Open clusters in a dispersing molecular cloud
Authors: Chen H.‐C. , Ko C.‐M.
Published: November 2008

Star clusters are formed in molecular clouds which are believed to be the birth places of most stars. From recent observational data, Lada & Lada (2003) estimated that only 4 to 7% of the proto‐clusters have survived. A possible reason is the dispersion of molecular clouds by UV radiation, stellar winds or supernova explosions. We study the cloud dispersion in the embedded clusters by N‐body simulations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The turbulent ISM and the stellar IMF
Authors: Clark P.C. , Klessen R.S.
Published: November 2008

In this contribution, we focus on the role that turbulence can play in setting the initial mass function (IMF) of stars. Two theories are contrasted. In the first, the so‐called ‘turbulent’ fragmentation theory, the turbulence is directly responsible for breaking up the cloud into ‘cores’ which go on to form either a single star or a small N system. In such a picture, the IMF is primordial, since the mass reservoir form the young protostellar system is assumed to be set by the mass of the natal core. In the alternative picture, ‘competitive accretion’, the final mass of a protostar is determined by its position in the potential well of the cluster. As such the IMF is determined through gravitational dynamics rather than turbulence. We discuss the observation motivation for each of these cases. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐resolution simulations of globular cluster dynamics
Authors: Heggie D.C. , Giersz M.
Published: November 2008

We describe the construction of a dynamical evolutionary model of a Galactic globular cluster, using the nearby cluster M4 as an example. The method is based on a Monte Carlo code for star cluster dynamics, but includes primordial binaries and their interactions, the Galactic tide, and stellar evolution of both single and binary stars. At the age of 12 Gyr the model gives a satisfactory match to the surface brightness profile, the velocity dispersion profile, and the luminosity function in two fields. According to the model, M4 is a post‐collapse cluster, even though the surface‐brightness profile places it within the class of “King profile” clusters.We also consider the evolution of the binary population and the escape velocity from the cluster centre. Full details are given in Heggie & Giersz (2008). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kinematics and chemical abundances ofmetal‐poor stars in the Galactic outer halo
Authors: Ishigaki M. , Chiba M. , Aoki W.
Published: November 2008

A survey of chemical abundances for Galactic metal‐poor stars, which are likely constituents of the outer part of the halo, is currently in progress. The sample analysed so far is comprised of 26 metal‐poor ([Fe/H] < –1) stars, whose estimated orbits reach >5 kpc above and below the Galactic plane. Using these sample stars selected based on their kinematics, we carried out the high‐resolution spectroscopy with Subaru/HDS and obtained their chemical abundances. The detailed abundance pattern of the outer halo stars has important clues for the progenitor systems populating the Galactic outer halo. The current status of our survey is reported. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Gaia project: Technique, performance and status
Authors: Jordan S.
Published: November 2008

Gaia is a satellite mission of the ESA, aiming at absolute astrometric measurements of about one billion stars (all stars down to 20th magnitude, with unprecedented accuracy. Additionally, magnitudes and colors will be obtained for all these stars, while radial‐velocities and spectral properties will be determined only for bright objects (V < 17.5). At 15th magnitude Gaia aims at an angular accuracy of 20 microarcseconds (μ as). This goal can only be reached if the geometry of the telescopes, the detectors, and the pointing of Gaia at each moment (“attitude”) can be inferred from the Gaia measurements itself with μ as accuracy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Young star clusters in the Antennae galaxies and NGC 1487
Authors: Mengel S. , Lehnert M.D. , Thatte N. , Whitmore B. , Vacca W.D. , Chandar R.
Published: November 2008

We estimate the dynamical masses of several young (≈ 10 Myr) massive star clusters in two interacting galaxies, NGC 4038/4039 (“The Antennae”) and NGC 1487, under the assumption of virial equilibrium. These are compared with photometric mass estimates. A dynamical mass substantially higher than the photometric estimate could indicate non‐virial motion of the stars in the cluster, and potentially lead to cluster disruption. All but one of the Antennae clusters have dynamical and photometric mass estimates which are within a factor ≈ 2 of one another, implying both that standard IMFs provide a good approximation to the IMF of these clusters, and that there is no significant extra‐virial motion, as would be expected if they were rapidly dispersing. These results suggest that almost all of the clusters in our sample have survived the gas removal phase as bound or marginally bound objects. But a few targets (two in NGC 1487 and one in the Antennae) have Mdyn estimates which are significantly larger than the photometric mass estimates. At least two of those clusters may be actively in the process of dissolving. The dissolution candidates in both galaxies are amongst the clusters with the lowest pressures/densities measured in our sample. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High M/L ratios of UCDs: A variation of the IMF?
Authors: Mieske S. , Dabringhausen J. , Kroupa P. , Hilker M. , Baumgardt H.
Published: November 2008

Various studies have established that the dynamical M/L ratios of ultra‐compact dwarf galaxies (UCDs) tend to be at the limit or beyond the range explicable by standard stellar populations with canonical IMF. We discuss how IMF variations may account for these high M/L ratios and how observational approaches may in the future allow to discriminate between those possibilities. We also briefly discuss the possibility of dark matter in UCDs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extragalactic archeology in integrated light: A test case with NGC 4030
Authors: Ocvirk P. , Peletier R. , Lançon A.
Published: November 2008

We reconstruct the age‐velocity distribution of the central region of the Sbc galaxy NGC4030, by applying STECKMAP to very high qualityWHT/ISIS data.We find that the main component is a relatively young (≈2 Gyr) bulge with a ≈100 km/s velocity dispersion. The best fit solution also shows a superimposed young, kinematically cold (σv ∼ 30 km/s) component. Monte‐Carlo simulations show that the detection of this component is robust given the observational setup and quality of the data, and that it is not likely to be an artifact of the inversion procedure. We propose that this component is actually a young stellar disk, seen superimposed on the bulge. This demonstrates the feasibility of separating superimposed stellar components and measuring their age and kinematics in integrated light, thereby confirming the results of Ocvirk et al. (2006b), but this time with real data. This is an important success for our tool in a series of tests and towards new results in extragalactic archeology. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling merging galaxies using MINGA: Improving restricted N‐body by dynamical friction
Authors: Petsch H.P. , Theis Ch.
Published: November 2008

Modeling interacting galaxies to reproduce observed systems is still a challenge due to the extended parameter space (among other problems). Orbit and basic galaxy parameters can be tackled by fast simulation techniques like the restricted N‐body method, applied in the fundamental work by Toomre & Toomre (1972). This approach allows today for the study of millions of models in a short time. One difficulty for the classical restricted N‐body method is the missing orbital decay, not allowing for galaxy mergers. Here we present an extension of the restricted N‐body method including dynamical friction. This treatment has been developed by a quantitative comparison with a set of self‐consistent merger simulations. By varying the dynamical friction (formalism, strength and direction), we selected the best‐fitting parameters for a set of more than 250 000 simulations. We show that our treatment reliably reproduces the orbital decay and tidal features of merging disk galaxies for mass ratios up to q = 1/3 between host and satellite. We implemented this technique into our genetic algorithm based modeling code MINGA and present first results. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
APOGEE: The Apache Point Observatory Galactic Evolution Experiment
Authors: Prieto C. Allende , Majewski S.R. , Schiavon R. , Cunha K. , Frinchaboy P. , Holtzman J. , Johnston K. , Shetrone M. , Skrutskie M. , Smith V. , Wilson J.
Published: November 2008

APOGEE is a large‐scale, NIR, high‐resolution (R ∼ 20 000) spectroscopic survey of Galactic stars. It is one of the four experiments in SDSS‐III. Because APOGEE will observe in the H band, where the extinction is six times smaller than in V, it will be the first survey to pierce through Galactic dust and provide a vast, uniform database of chemical abundances and radial velocities for stars across all Galactic populations (bulge, disk, and halo). The survey will be conducted with a dedicated, 300‐fiber, cryogenic, spectrograph that is being built at the University of Virginia, coupled to the ARC 2.5‐m telescope at Apache Point Observatory. APOGEE will use a significant fraction of the SDSS‐III bright time during a three‐year period to observe, at high signal‐to‐noise ratio (S /N > 100), about 100 000 giant stars selected directly from 2MASS down to a typical flux limit ofH < 13. The main scientific objectives of APOGEE are: (1) measuring unbiased metallicity distributions and abundance patterns for the different Galactic stellar populations, (2) studying the processes of star formation, feedback, and chemical mixing in theMilkyWay, (3) surveying the dynamics of the bulge and disk, placing constraints on the nature and influence of the Galactic bar and spiral arms, and (4) using extensive chemodynamical data, particularly in the inner Galaxy, to unravel its formation and evolution. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A dark disc in the Milky Way
Authors: Read J.I. , Lake G. , Agertz O. , Debattista V.
Published: November 2008

Predicting the flux of dark matter particles through the Earth is vital for current and future direct dark matter detection experiments. To date, such predictions have been based on simulations that model the dark matter alone. Here we make the first attempt to include the influence of the baryonic matter. We show that the presence of a stellar/gas disc at high redshift (z ∼ 1) causes merging satellites to be preferentially dragged towards the disc plane. This results in an accreted stellar disc, and a dark matter disc that contributes ρDDISC = 0.25–1 ρHALO at the solar position. Although not likely to be dynamically interesting, the dark disc has important implications for the direct detection of dark matter because of ist low velocity with respect to the Earth. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The construction of equilibrium phase models of stellar systems by the iterative method
Authors: Rodionov S.A. , Athanassoula E. , Sotnikova N.Ya.
Published: November 2008

We describe a method, called the iterative method, which can be used to construct equilibrium N ‐body models with a given mass distribution and with given kinematic properties, parameters, or constraints. This method is both very simple and very powerful and can be used for mass distributions with an arbitrary geometry and a large variety of kinematical constraints. Applications of this method include the creation of initial conditions forN ‐body simulations and the modelling of galaxies from their photometric and kinematic observations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Peculiarities in the stellar velocity distribution of galaxies with a two‐armed spiral structure
Authors: Vorobyov E.I. , Theis Ch.
Published: November 2008

We expand our previous numerical study of the properties of the stellar velocity distribution within the disk of a twoarmed spiral galaxy by considering spiral stellar density waves with different global Fourier amplitudes, C2. We confirm our previous conclusion that the ratio σ1: σ2 of smallest versus largest principal axes of the stellar velocity ellipsoid becomes abnormally small near the outer edges of the stellar spiral arms. The extent to which the stellar velocity ellipsoid is elongated (as compared to the unperturbed value typical for the axisymmetric disk) increases with the strength of the spiral density wave. In particular, the C2 = 0.06 spiral can decrease the unperturbed value of σ1: σ2 by 20%, while the C2 = 0.13 spiral can decrease the unperturbed σ1: σ2 by a factor of 3. The abnormally small values of the σ1: σ2 ratio can potentially be used to track the position of stellar spiral density waves. The σϕϕ: σrr ratio is characterized by a more complex behaviour and exhibits less definite minima near the outer edges of the spiral arms. We find that the epicycle approximation is violated near the spiral arms and cannot be used in spiral galaxies with C2 ≳ 0.05–0.06 or in galaxies with the amplitude of the spiral stellar density wave (relative to the unperturbed background) of order 0.1 or greater. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Star cluster kinematics in the GAIA era
Authors: Baumgardt H.
Published: November 2008

The GAIA astrometric satellite will measure positions, proper motions and parallaxes of millions of stars with microarcsecond accuracy. This will greatly increase our understanding of the stellar populations of the Milky Way and their dynamics. In particular, it will be possible to determine internal and space motions of a large number of open or globular clusters with an accuracy of a few km/s or better, which will bring new insights into the way star clusters evolve and how they and the Milky Way as a whole have formed. It will also be possible to look for clusters which have a common space motion and follow tidal streams from dissolving globular clusters over many orbits by kinematically selecting their members, which will constrain the form of the galactic potential. I illustrate how GAIA will improve our knowledge on the kinematics and dynamics of star clusters and what can be learned by comparing the GAIA data with realistic N ‐body simulations of star clusters, possible with e.g. future GPU or GRAPE computers. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
RAVE: First results and 2nd data release
Authors: Siebert A. , the RAVE collaboration
Published: November 2008

RAVE, the RAdial Velocity Experiment, is an ambitious program to conduct a survey to measure the radial velocities, metallicities and abundance ratios for up to a million stars using the 1.2‐m UK Schmidt Telescope of the Anglo‐Australian Observatory (AAO), over the period 2003–2010. The survey represents a giant leap forward in our understanding of our own Milky Way galaxy, providing a vast stellar kinematic database larger than any other survey proposed for this coming decade. The main data product will be a southern hemisphere survey of about a million stars. This survey would comprise 0.7 million thin disk main sequence stars, 250 000 thick disk stars, 100 000 bulge and halo stars, and a further 50 000 giant stars including some out to 10 kpc from the Sun. RAVE will offer the first truly representative inventory of stellar radial velocities for all major components of the Galaxy. Here we present the first scientific results of this survey as well as its second data release which doubles the number of previously released radial velocities. For the first time, the release also provides atmospheric parameters for a large fraction of the 2nd year data making it an unprecedented tool to study the formation of the Milky Way. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Novel Fluidized‐Bed Membrane Dual‐Type Reactor Concept for Methanol Synthesis
Authors: Rahimpour M. R. , Alizadehhesari K.
Published: November 2008

A novel fluidized‐bed membrane dual‐type methanol reactor (FBMDMR) concept is proposed in this paper. In this proposed reactor, the cold feed synthesis gas is fed to the tubes of the gas‐cooled reactor and flows in counter‐current mode with a reacting gas mixture in the shell side of the reactor, which is a novel membrane‐assisted fluidized bed. In this way, the synthesis gas is heated by heat of reaction which is produced in the reaction side. Hydrogen can penetrate from the feed synthesis gas side into the reaction side as a result of a hydrogen partial pressure difference between both sides. The outlet synthesis gas from this reactor is fed to tubes of the water‐cooled packed bed reactor and the chemical reaction is initiated by the catalyst. The partially converted gas leaving this reactor is directed into the shell of the gas‐cooled reactor and the reactions are completed in this fluidized‐bed side. This reactor configuration solves some drawbacks observed from the new conventional dual‐type methanol reactor, such as pressure drop, internal mass transfer limitations, radial gradient of concentration, and temperature in the gas‐cooled reactor. The two‐phase theory of fluidization is used to model and simulate the proposed reactor. An industrial dual‐type methanol reactor (IDMR) and a fluidized‐bed dual‐type methanol reactor (FBDMR) are used as a basis for comparison. This comparison shows enhancement in the yield of methanol production in the fluidized‐bed membrane dual‐type methanol reactor (FBMDMR).
Microwave Synthesis of SAPO‐11 and AlPO‐11: Aspects of Reactor Engineering
Authors: Gharibeh Murad , Tompsett Geoffrey. A. , Conner William Curtis , Yngvesson K. Sigfrid
Published: November 2008

AlPO‐11 and SAPO‐11 are synthesized using microwave heating. The effects of precursor volume, reaction temperature, reactor geometry, stirring, applicator type and frequency on the microwave synthesis of SAPO‐11 and AlPO‐11 are studied. The nucleation time and crystallization rate are determined from crystallization curves for SAPO‐11 (and/or AlPO‐11), for the various parameters investigated. Increasing volume of the reacting material decreases the reaction rate of SAPO‐11 at 160°C. In particular, the nucleation time increases with increase in the reaction volume. Increasing the reaction temperature increases the crystallization rate and decreases the nucleation time, however it decreases the particle size. Nucleation of SAPO‐11 and AlPO‐11 under microwave heating is strongly dependant on the reaction temperature. Using wider geometry vessel (33 mm compared to 11 mm diameter) enhances the reaction rate, producing larger crystals in the same reaction time, even though the crystallization rate is decreased. The crystallization rate is enhanced by applicator type in the following order CEM MARS‐5 oven>CEM Discover “focused” system>monomode waveguide. Stirring the reacting solution during heating affects primarily the nucleation time. The effect of microwave frequency on the nucleation and growth of SAPO‐11 shows a dependence on the applicator type more than the specific frequency, for the frequency range 2.45–10.5 GHz. The difference between the crystallization rate observed at higher frequencies and that at 2.45 GHz maybe due to the multimode nature of the waveguide at frequencies above 2.45 GHz. Sweeping the microwave frequency linearly between 8.7 and 10.5 GHz at rates of 10 min−1 and 100 min−1 shows an intermediate crystallization curve to that for fixed frequencies of 2.45 GHz and that for 5.8, 8.7 and 10.5 GHz.
Identification and expression of voltage‐gated calcium channel β subunits in Zebrafish
Authors: Zhou Weibin , Horstick Eric James , Hirata Hiromi , Kuwada John Y.
Published: November 2008

Voltage‐gated calcium channels (VGCC) play important roles in electrically excitable cells and embryonic development. The VGCC β subunits are essential for membrane localization of the channel and exert modulatory effects on channel functions. In mammals, the VGCC β subunit gene family contains four members. In zebrafish, there appear to be seven VGCC β subunits including the previously identified β1 subunit. cDNAs for six additional VGCC β subunit homologs were identified in zebrafish, their chromosomal locations determined and their expression patterns characterized during embryonic development. These six genes are primarily expressed in the nervous system withcacnb4aalso expressed in the developing heart. Sequence homology, genomic synteny and expression patterns suggest that there are three pairs of duplicate genes for β2, β3, and β4 in zebrafish with distinct expression patterns during embryonic development. Developmental Dynamics 237:3842–3852, 2008. © 2008 Wiley‐Liss, Inc.
The acyltransferase gene bus‐1 exhibits conserved and specific expression in nematode rectal cells and reveals pathogen‐induced cell swelling
Authors: Gravato‐Nobre Maria J. , Hodgkin Jonathan
Published: November 2008

Susceptibility to the rectal pathogen Microbacterium nematophilum provides a means of examining hindgut differentiation in C. elegans. Mutants of bus‐1 are resistant to infection with this pathogen. We show here that bus‐1 encodes a predicted acyltransferase expressed in rectal epithelial cells (K, F, and U), suggesting its involvement in regional surface modification. bus‐1 reporter genes were used to show spatial regulation by hindgut developmental control genes: egl‐38, mab‐9, and mab‐23. A bus‐1::GFP reporter reveals the conspicuous rectal epithelial swelling induced by M. nematophilum. The C. briggsae ortholog of bus‐1 exhibits conserved function and rectal expression, but it is expressed in vulval as well as rectal cells, correlated with pathogen adhesion to both vulval and rectal cells in this species. Another acyltransferase affecting bacterial adhesion, bus‐18/acl‐10, was also identified, which also shows strong rectal expression, but it is expressed in additional epithelial tissues and is required for general surface integrity. Developmental Dynamics 237:3762–3776, 2008. © 2008 Wiley‐Liss, Inc.
hgf/c‐met expression and functional analysis during zebrafish embryogenesis
Authors: Latimer Andrew J. , Jessen Jason R.
Published: November 2008

Hepatocyte growth factor (HGF) and its receptor tyrosine kinase Met are linked to several processes underlying vertebrate development and cancer progression. Here, we characterized the expression of zebrafish c‐met, hgf1, and hgf2 from cleavage stages through organogenesis and initiated an analysis of Met signaling. We identified c‐met as a marker of endoderm and demonstrated that its expression can be activated downstream of Nodal. Injection of c‐met mRNA drives expression of the endodermal gene sox17. During gastrulation, hgf1 transcripts are visible in mesendodermal cells along the midline. Later, c‐met is expressed in kidney, islet2‐positive neurons, and liver. We show that hgf1 is transcribed during gastrulation while hgf1 and hgf2 are detectable in pharyngeal arches and swim bladder. Similar to mouse, knockdown of zebrafish Met reduces liver size. Our results suggest a role for Met during endoderm specification and indicate that mechanisms of liver development are conserved between mammals and bony fish. Developmental Dynamics 237:3904–3915, 2008. © 2008 Wiley‐Liss, Inc.
Cooperative interaction of Nkx2.5 and Mef2c transcription factors during heart development
Authors: Vincentz Joshua W. , Barnes Ralston M. , Firulli Beth A. , Conway Simon J. , Firulli Anthony B.
Published: November 2008

The interactions of diverse transcription factors mediate the molecular programs that regulate mammalian heart development. Among these, Nkx2.5 and the Mef2c regulate common downstream targets and exhibit striking phenotypic similarities when disrupted, suggesting a potential interaction during heart development. Co‐immunoprecipitation and mammalian two‐hybrid experiments revealed a direct molecular interaction between Nkx2.5 and Mef2c. Assessment of mRNA expression verified spatiotemporal cardiac coexpression. Finally, genetic interaction studies employing histological and molecular analyses showed that, although Nkx2.5−/− and Mef2c−/− individual mutants both have identifiable ventricles, Nkx2.5−/−;Mef2c−/− double mutants do not, and that mutant cardiomyocytes express only atrial and second heart field markers. Molecular marker and cell death and proliferation analyses provide evidence that ventricular hypoplasia is the result of defective ventricular cell differentiation. Collectively, these data support a hypothesis where physical, functional, and genetic interactions between Nkx2.5 and Mef2c are necessary for ventricle formation. Developmental Dynamics 237:3809–3819, 2008. © 2008 Wiley‐Liss, Inc.
The lim domain only protein 7 is important in zebrafish heart development
Authors: Ott Elisabeth B. , van den Akker Nynke M. S. , Sakalis Philippe A. , Gittenberger‐de Groot Adriana C. , Te Velthuis Aartjan J.W. , Bagowski Christoph P.
Published: November 2008

The LIM domain only protein 7 (LMO7), a member of the PDZ and LIM domain‐containing protein family is a candidate gene with possible roles in embryonic development and breast cancer progression. LMO7 has been linked to actin cytoskeleton organization through nectin/afadin and to cell–cell adhesion by means of E‐cadherin/catenin. In addition, LMO7 has been shown to regulate transcription of the nuclear membrane protein Emerin and other muscle relevant genes. In this study, we used in situ hybridization to investigate LMO7 expression during embryonic development in three widely used vertebrate model species: the zebrafish, the chicken and the mouse. Our temporal and spatial gene expression analysis revealed both common and distinct patterns between these species. In mouse and chicken embryos we found expression in the outflow tract, the inflow tract, the pro‐epicardial organ and the second heart field, structures highly important in the developing heart. Furthermore, gene knockdown experiments in zebrafish embryos resulted in severe defects in heart development with effects on the conduction system and on heart localization. In summary, we present here the first developmental study of LMO7. We reveal the temporal and spatial expression patterns of this important gene during mouse, chicken and fish development and our findings suggest essential functions for LMO7 during vertebrate heart development. Developmental Dynamics 237:3940–3952, 2008. © 2008 Wiley‐Liss, Inc.
VEGF‐mediated fusion in the generation of uniluminal vascular spheroids
Authors: Gentile Carmine , Fleming Paul A. , Mironov Vladimir , Argraves Kelley M. , Argraves W. Scott , Drake Christopher J.
Published: November 2008

VEGF‐mediated vascular fusion in the generation of uniluminal spheroids. Luminized vascular networks present in mouse allantoic‐derived tissue spheroids (upper image) fuse when treated with VEGF to form a single central vessel (lower image). Spheroids were immunolabeled with antibodies to PECAM‐1 (green) and SMαA (red). See Gentile et al., Developmental Dynamics 237:2918–2925. Developmental Dynamics 237:2918–2925, 2008. © 2008 Wiley‐Liss, Inc.
Governance challenges and the prevention of industrial environmental accidents: the case of finland
Authors: Wessberg Nina , Molarius Riitta
Published: November 2008

This paper examines the challenges faced in governing accidental industrial emissions. Accidental emissions are unexpected situations where harmful runaway emissions are released into the environment, causing damage to people, ecosystems, human property and company images. We claim that in Finland the practices of environmental authorities do not encourage companies to prevent accidental emissions in the most effective way. According to our study, based on action research and case study augmented with document analysis and interviews, authorities operate under three different kinds of frame: an environmental permit frame, a risk prevention frame and a major accident prevention frame. Accidental industrial emissions are, in our view, best governed under the risk prevention frame, where practices and management systems are addressed covering the entire complex socio‐technical nature of an industrial process. However, environmental authorities, in Finland, focus on environmental permit frames, stressing limit values, hence concentrating on managing the industrial process component by component. This approach may be suitable for the governing of continuous emissions, but not that of accidental emissions. Copyright © 2008 John Wiley & Sons, Ltd and ERP Environment.