bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnosis of Tropospheric Moisture over Saudi Arabia and Influences of IOD and ENSO
Authors: Chakraborty Arun , Behera Swadhin K. , Mujumdar Milind , Ohba Ryohji , Yamagata Toshio
Published: March 2006

A diagnostic study of atmospheric moisture data over Saudi Arabia derived from a 43-yr National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis revealed that moisture convergence in the lower troposphere and divergence in and above the middle troposphere occurs throughout the year. Although the amount of precipitable water content in the middle troposphere is high, precipitation is less than expected over this semiarid region during a boreal summer monsoon season because of strong moisture divergence. The net tropospheric moisture flux over the arid and semiarid regions of Saudi Arabia shows seasonal and interannual variability. The seasonal variability has a strong semiannual signal with its primary peak February–April and its secondary peak June–August. This pattern is consistent with a similar semiannual signal observed in rainfall climatology. The restricted moisture supply to southwestern Saudi Arabia during summer presumably explains the lack of precipitation in other areas of the country. Winter precipitation, however, is widespread. The increased transport of net atmospheric moisture flux is higher during El Niño and positive Indian Ocean dipole (IOD) phenomena. During these events, influx across the Red Sea (west) side of Saudi Arabia increases. The net flux to the region is reduced by a slight increase of outflux across the Persian Gulf (east) side. Reanalysis data and model-sensitivity experiments show that El Niño or a concurrent positive IOD and El Niño event more strongly amplify net transport than does an independent positive IOD event. The partial-lag correlation analysis with net moisture flux from the Red Sea side shows that the positive IOD mode has a peak correlation coefficient of ∼0.5 with close to a 5-month lead and that El Niño has a peak correlation coefficient of ∼0.6 with close to a 2-month lead.
MOS, Perfect Prog, and Reanalysis
Authors: Marzban Caren , Sandgathe Scott , Kalnay Eugenia
Published: March 2006

Statistical postprocessing methods have been successful in correcting many defects inherent in numerical weather prediction model forecasts. Among them, model output statistics (MOS) and perfect prog have been most common, each with its own strengths and weaknesses. Here, an alternative method (called RAN) is examined that combines the two, while at the same time utilizes the information in reanalysis data. The three methods are examined from a purely formal/mathematical point of view. The results suggest that whereas MOS is expected to outperform perfect prog and RAN in terms of mean squared error, bias, and error variance, the RAN approach is expected to yield more certain and bias-free forecasts. It is suggested therefore that a real-time RAN-based postprocessor be developed for further testing.
Sensitivity of Hurricane Intensity Forecast to Convective Momentum Transport Parameterization
Authors: Han Jongil , Pan Hua-Lu
Published: March 2006

A parameterization of the convection-induced pressure gradient force (PGF) in convective momentum transport (CMT) is tested for hurricane intensity forecasting using NCEP's operational Global Forecast System (GFS) and its nested Regional Spectral Model (RSM). In the parameterization the PGF is assumed to be proportional to the product of the cloud mass flux and vertical wind shear. Compared to control forecasts using the present operational GFS and RSM where the PGF effect in CMT is taken into account empirically, the new PGF parameterization helps increase hurricane intensity by reducing the vertical momentum exchange, giving rise to a closer comparison to the observations. In addition, the new PGF parameterization forecasts not only show more realistically organized precipitation patterns with enhanced hurricane intensity but also reduce the forecast track error. Nevertheless, the model forecasts with the new PGF parameterization still largely underpredict the observed intensity. One of the many possible reasons for the large underprediction may be the absence of hurricane initialization in the models.
3DVAR and Cloud Analysis with WSR-88D Level-II Data for the Prediction of the Fort Worth, Texas, Tornadic Thunderstorms. Part I: Cloud Analysis and Its Impact
Authors: Hu Ming , Xue Ming , Brewster Keith
Published: March 2006

In this two-part paper, the impact of level-II Weather Surveillance Radar-1988 Doppler (WSR-88D) reflectivity and radial velocity data on the prediction of a cluster of tornadic thunderstorms in the Advanced Regional Prediction System (ARPS) model are studied. Radar reflectivity data are used primarily in a cloud analysis procedure that retrieves the amount of hydrometeors and adjusts in-cloud temperature, moisture, and cloud fields, while radial velocity data are analyzed through a three-dimensional variational (3DVAR) scheme that contains a mass divergence constraint in the cost function. In Part I, the impact of the cloud analysis and modifications to the scheme are examined while Part II focuses on the impact of radial velocity and the mass divergence constraint.

The case studied is that of the 28 March 2000 Fort Worth, Texas, tornado outbreaks. The same case was studied by Xue et al. using the ARPS Data Analysis System (ADAS) and an earlier version of the cloud analysis procedure with WSR-88D level-III data. Since then, several modifications to the cloud analysis procedure, including those to the in-cloud temperature adjustment and the analysis of precipitation species, have been made. They are described in detail with examples.

The assimilation and predictions use a 3-km grid nested inside a 9-km one. The level-II reflectivity data are assimilated, through the cloud analysis, at 10-min intervals in a 1-h period that ends a little over 1 h preceding the first tornado outbreak. Experiments with different settings within the cloud analysis procedure are examined. It is found that the experiment using the improved cloud analysis procedure with reflectivity data can capture the important characteristics of the main tornadic thunderstorm more accurately than the experiment using the early version of cloud analysis. The contributions of different modifications to the above improvements are investigated.
3DVAR and Cloud Analysis with WSR-88D Level-II Data for the Prediction of the Fort Worth, Texas, Tornadic Thunderstorms. Part II: Impact of Radial Velocity Analysis via 3DVAR
Authors: Hu Ming , Xue Ming , Gao Jidong , Brewster Keith
Published: March 2006

In this two-part paper, the impact of level-II Weather Surveillance Radar-1988 Doppler (WSR-88D) radar reflectivity and radial velocity data on the prediction of a cluster of tornadic thunderstorms in the Advanced Regional Prediction System (ARPS) model is studied. Radar reflectivity data are used primarily in a cloud analysis procedure that retrieves the amount of hydrometeors and adjusts in-cloud temperature, moisture, and cloud fields, while radial velocity data are analyzed through a three-dimensional variational (3DVAR) data assimilation scheme that contains a 3D mass divergence constraint in the cost function. In Part I, the impact of the cloud analysis and modifications to the scheme are discussed. In this part, the impact of radial velocity data and the mass divergence constraint in the 3DVAR cost function are studied.

The case studied is that of the 28 March 2000 Fort Worth tornadoes. The addition of the radial velocity improves the forecasts beyond that experienced with the cloud analysis alone. The prediction is able to forecast the morphology of individual storm cells on the 3-km grid up to 2 h; the rotating supercell characteristics of the storm that spawned two tornadoes are well captured; timing errors in the forecast are less than 15 min and location errors are less than 10 km at the time of the tornadoes.

When forecasts were made with radial velocity assimilation but not reflectivity, they failed to predict nearly all storm cells. Using the current 3DVAR and cloud analysis procedure with 10-min intermittent assimilation cycles, reflectivity data are found to have a greater positive impact than radial velocity. The use of radial velocity does improve the storm forecast when combined with reflectivity assimilation, by, for example, improving the forecasting of the strong low-level vorticity centers associated with the tornadoes. Positive effects of including a mass divergence constraint in the 3DVAR cost function are also documented.
Tests of an Ensemble Kalman Filter for Mesoscale and Regional-Scale Data Assimilation. Part I: Perfect Model Experiments
Authors: Zhang Fuqing , Meng Zhiyong , Aksoy Altug
Published: March 2006

Through observing system simulation experiments, this two-part study exploits the potential of using the ensemble Kalman filter (EnKF) for mesoscale and regional-scale data assimilation. Part I focuses on the performance of the EnKF under the perfect model assumption in which the truth simulation is produced with the same model and same initial uncertainties as those of the ensemble, while Part II explores the impacts of model error and ensemble initiation on the filter performance. In this first part, the EnKF is implemented in a nonhydrostatic mesoscale model [the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5)] to assimilate simulated sounding and surface observations derived from simulations of the “surprise” snowstorm of January 2000. This is an explosive East Coast cyclogenesis event with strong error growth at all scales as a result of interactions between convective-, meso-, and subsynoptic-scale dynamics.

It is found that the EnKF is very effective in keeping the analysis close to the truth simulation under the perfect model assumption. The EnKF is most effective in reducing larger-scale errors but less effective in reducing errors at smaller, marginally resolvable scales. In the control experiment, in which the truth simulation was produced with the same model and same initial uncertainties as those of the ensemble, a 24-h continuous EnKF assimilation of sounding and surface observations of typical temporal and spatial resolutions is found to reduce the error by as much as 80% (compared to a 24-h forecast without data assimilation) for both observed and unobserved variables including zonal and meridional winds, temperature, and pressure. However, it is observed to be relatively less efficient in correcting errors in the vertical velocity and moisture fields, which have stronger smaller-scale components. The analysis domain-averaged root-mean-square error after 24-h assimilation is ∼1.0–1.5 m s−1 for winds and ∼1.0 K for temperature, which is comparable to or less than typical observational errors. Various sensitivity experiments demonstrated that the EnKF is quite successful in all realistic observational scenarios tested. However, as will be presented in Part II, the EnKF performance may be significantly degraded if an imperfect forecast model is used, as is likely the case when real observations are assimilated.
Knowledge Creation in New Product Development Projects
Authors: Schulze Anja , Hoegl Martin
Published: March 2006

In this article, the authors develop and test hypotheses relating the four knowledge creation modes of socialization, externalization, combination, and internalization as performed during the concept and the development phases of new product development projects to new product success. Using data from 94 new product development projects, they find that socialization during the concept phase and combination during the development phase are positively related to new product success but that externalization during the concept phase as well as socialization and internalization during the development phase are negatively related to new product success. Implications for theory and practice are discussed.
Do Organizational Socialization Tactics Influence Newcomer Embeddedness and Turnover?
Authors: Allen David G.
Published: March 2006

The author proposes that socialization tactics influence newcomer turnover by embedding newcomers more extensively into the organization. Hypotheses are tested with a sample of newcomers in a large financial services organization. Results reveal that socialization tactics enable organizations to actively embed new employees; collective, fixed, and investiture tactics were positively related to on-the-job embeddedness. Results also indicate that on-the-job embeddedness is negatively related to turnover and mediates relationships between some socialization tactics and turnover.
Organizational Justice in an Exchange Framework: Clarifying Organizational Justice Distinctions
Authors: Roch Sylvia G. , Shanock Linda R.
Published: March 2006

The authors used exchange theory to clarify distinctions between organizational justice types and considered the implications of recent conceptual developments regarding justice associated with interpersonal treatment (interactional justice) and the inclusion of justice associated with outcomes (distributive justice) for an exchange model of justice. Using two samples (401 part-time and 272 full-time employees), they found unique relationships of interactional justice and justice concerning informational adequacy with supervisor relationship quality, justice concerning procedures with organizational support, and distributive justice with pay satisfaction. Also, an updated measure of interactional justice appears to capture more of the interpersonal fairness domain than the current measure.
Intersubjectivity – interactionist or discursive? Reflections on Habermas’ critique of Brandom
Authors: Strydom Piet
Published: March 2006

This article argues that there is a marked ambivalence in Habermas’ concept of intersubjectivity in that he wavers between an interactionist and a discursive understanding. This ambivalence is demonstrated with reference to his recent critique of Robert Brandom's normative pragmatic theory of discursive practice. Although Habermas is a leading theorist of discourse as an epistemically steered process, he allows his interpretation of Brandom's theory as suffering from objective idealism to compel him to recoil from discourse and to defend a purely interactionist or dialogical position. It is argued that the ambivalence in question is related to Habermas’ incomplete theorization of communication as a process of structure formation that unfolds sequentially through time on different levels. His architectonic of communicative intersubjectivity is marred by a missing concept. His characteristic concept of coordination is insufficient and must be complemented by a concept of synthesis at the discursive level.
Affinities in the socio-political thought of Rorty and Levinas
Authors: Jordaan Eduard
Published: March 2006

This article considers the affinities in the socio-political thought of Emmanuel Levinas and Richard Rorty. The writings of both display considerable concern for the suffering of others. Both authors note the importance of a self-critical subject becoming more aware of its own injustice as very important for recognizing our responsibilities to others. Furthermore, both stress the importance of recognizing the other outside of the usual, objectifying categories, since it is the uniqueness of the other that reminds us of our responsibility for the other. Both writers view the liberal state as the best political forum in which to realize a fuller recognition of and responsibility towards the other, a form of state in which the ethical constantly interrupts the political. Rorty and Levinas disagree, however, on the legitimacy of not responding to the other.
Adorno and the disenchantment of nature
Authors: Stone Alison
Published: March 2006

In this article I re-examine Adorno's and Horkheimer's account of the disenchantment of nature in Dialectic of Enlightenment. I argue that they identify disenchantment as a historical process whereby we have come to find natural things meaningless and completely intelligible. However, Adorno and Horkheimer believe that modernity not only rests on disenchantment but also tends to re-enchant nature, because it encourages us to think that its institutions derive from, and are anticipated and prefigured by, nature. I argue that Adorno's Negative Dialecticsand Aesthetic Theory show how constellations and artworks generate an alternative form of reenchantment which is critical of modernity and its domination of nature. This form of re-enchantment finds natural beings to be mysteriously meaningful because they embody histories of immeasurable suffering. This experience engenders guilt and antipathy to human domination over nature.
Artworks in Word and Image
Authors: Gadamer Hans-Georg
Published: March 2006

The arts, taken as whole, govern the metaphysical heritage of the western philosophical tradition. The arts possess absoluteness in that in the experience of art we recognize something as ‘aright’, as true. Art also possesses absoluteness because it transcends all historical differences between eras. Art - and philosophy - possess a contemporaneity in that they attune themselves to the present time. Art is thus not a refined pleasure but something that shows us a world that is there for itself and as such. The significance of art therefore cannot be understood aesthetically but only through Plato’s theory of ‘the exact’ and the Aristotelian conception of energeia as a motion without a path or a goal.
“No Way My Boys Are Going to Be Like That!”
Authors: Kane Emily W.
Published: March 2006

Drawing on qualitative interviews with parents of preschool children, the author addresses parental responses to children’s gender nonconformity. The author’s analyses indicate that parents welcome what they perceive as gender nonconformity among their young daughters, while their responses in relation to sons are more complex. Many parents across racial and class backgrounds accept or encourage some tendencies they consider atypical for boys. But this acceptance is balanced by efforts to approximate hegemonic ideals of masculinity. The author considers these patterns in the context of gender as an interactional accomplishment, demonstrating that parents are often consciously aware of their own role in accomplishing gender with and for their sons. Heterosexual fathers are especially likely to be motivated in that accomplishment work by their own personal endorsement of hegemonic masculinity, while heterosexual mothers and gay parents are more likely to be motivated by accountability to others in relation to those ideals.
Circumventing Discrimination
Authors: Shih Johanna
Published: March 2006

This article compares the experiences of U.S.-born white women, Asian men, and Asian women immigrant engineers in Silicon Valley. It focuses on two particular characteristics of the region’s economic structure: the norm of job-hopping and the centrality of networks to high-skilled workers’ career livelihoods. While these characteristics might be assumed to exacerbate ethnic and gender inequality, the specific history of these groups’ entrance into Silicon Valley’s hi-tech industry enabled them to use these characteristics to their advantage in circumventing bias. The comparison of white women’s strategies to Asian immigrant men’s and women’s strategies highlights the interaction between the structure of opportunities, group histories, and network resources.
Public Libraries in England: A valuable public service or a service in distress?
Authors: Goulding Anne
Published: March 2006

Compares and contrasts the Department of Culture, Media and Sport Select Committee Reports of 2000 and 2005. Suggests that an increasing focus on public library matters can mean either that public libraries are moving up the political agenda or that they are a cause for concern. Discusses how the two reports show developments but also failings in public library service policy and provision over the five-year period. Both reports cover the regulatory framework governing public libraries but the 2005 report documents changes to reporting systems which, it is feared, will not improve the standard of below standard library services. Concerns about access to library buildings also featured in both reports. The success of the People's Network was praised in both 2000 and 2005 although the practice in some library authorities of charging for access to ICT was condemned strongly in the latter. The two reports emphasized the problem of the decline in the book lending service caused by a fall in the value of the book fund. It is concluded that although the 2005 report contains many criticisms of the provision and management of public library services in England, these should be viewed as an opportunity by the public library community to lobby local and national politicians for funding and action to rectify the problems identified.
Library media program implementation and student achievement
Authors: Farmer Lesley S.J.
Published: March 2006

This study examines possible factors related to school library programs that correlate with student academic achievement. Analyzing library programs as a system, the investigator adapted the American Association of School Librarians (AASL) principles for library media programs in conjunction with standardized tests. For the population examined (60 southern California schools), the measure that correlated most closely with library program principles was standardized reading scores. Specifically, the degree to which information access/delivery principles were implemented correlates significantly with student reading scores. The study results identified key indicators within the library program that impact student academic achievement: access to high-quality library facilities and resources, and collaborative planning with professional library staff.
From Baghdad to Paris
Authors: Cherribi Sam
Published: March 2006

This article analyzes the key ways in which Al-Jazeera brings the veil onto the screen and into its network current affairs, news, and religious programming and how it reported on the story of the veil in France between late 2002 and early 2005. Although much of the extant literature on Al-Jazeera describes it as the “CNN of the Arab world,” it is more like an Islamic version of CBN (Christian Broadcasting Network) than the secular or nonreligious CNN (Cable Network News) because of the time it devotes to the views of Islamic religious leaders and the ways in which it promotes Islamic practices. Al-Jazeera is not a “liberal” or “neutral” channel; it is a religious and news channel that allows other programs that are liberal or neutral to be shown occasionally.If the news broadcast on Al-Jazeera is pluralist,the religious message that it disseminates almost daily is monodenominational.The author argues that Al-Jazeera is using the issue of the veil in France to influence viewers in France and Europe,build a global Muslim identity,mobilize a shared public opinion,and construct an imagined transnational Muslim community.
The Sources of Four Commonly Reported Cutoff Criteria
Authors: Lance Charles E. , Butts Marcus M. , Michels Lawrence C.
Published: March 2006

Everyone can recite methodological “urban legends” that were taught in graduate school, learned over the years through experience publishing, or perhaps just heard through the grapevine. In this article, the authors trace four widely cited and reported cutoff criteria to their (alleged) original sources to determine whether they really said what they are cited as having said about the cutoff criteria, and if not, what the original sources really said. The authors uncover partial truths in tracing the history of each cutoff criterion and in the end endorse a set of 12 specific guidelines for effective academic referencing provided by Harzing that, if adopted, should help prevent the further perpetuation of methodological urban legends.
Method Variance in Organizational Research
Authors: Spector Paul E.
Published: March 2006

It has become widely accepted that correlations between variables measured with the same method, usually self-report surveys, are inflated due to the action of common method variance (CMV), despite a number of sources that suggest the problem is overstated. The author argues that the popular position suggesting CMV automatically affects variables measured with the same method is a distortion and oversimplification of the true state of affairs, reaching the status of urban legend. Empirical evidence is discussed casting doubt that the method itself produces systematic variance in observations that inflates correlations to any significant degree. It is suggested that the term common method variance be abandoned in favor of a focus on measurement bias that is the product of the interplay of constructs and methods by which they are assessed. A complex approach to dealing with potential biases involves their identification and control to rule them out as explanations for observed relationships using a variety of design strategies.
Reproductive consumption
Authors: Fletcher Ruth
Published: March 2006

Significant developments in medical research and technology have meant that the process of reproduction is increasingly affected by the consumption of a variety of services and goods. Individuals intervene in their own reproductive processes as they eat particular foods, take particular drugs and avail themselves of diagnostic and reproductive services. Although such developments have been analysed by feminists in terms of their ethical consequences or their contribution to the commodification of reproduction, they have not been evaluated in terms of their contribution to reproductive consumption. This article argues that we can avoid the reductiveness of critiques of commodified reproduction by developing a conceptual framework of reproductive consumption. Thinking through reproductive consumption also enables feminist analysis to expand our understanding of the gendered aspects of consumption. Most feminist work on consumption practices has focused on the domestic sphere as a site of consumption or on the role of sex and sexuality in promoting consumption. This article's analysis of reproductive consumption adds to this work by revealing ways in which biological reproduction itself is a site of consuming desires and needs, and is permeated by socio-economic forces. In developing a theoretical framework for analysing reproductive consumption, this article argues that consumption produces adaptive value as an object of exchange is acquired and adapted in order to satisfy some need or desire. In making this argument I draw on O'Brien, who argued that reproduction produces syntheticvalue by synthesizing reason and nature in bringing another human being into the world. In doing so she used Marx's method of extracting the concept of commodity value from capitalist exchange relations. Similarly, I analyse the relations of consumption in order to distil a value that is specific to consumption. Reproductive consumption identifies the reproductive consumer as someone who adapts objects of consumption to her own reproductive needs and desires as she negotiates her reproductive nature. Thinking about reproduction and consumption in terms of each other helps us to identify how reproduction is brought about through a taste for particular goods and services, and how consumption works through the reproductive, as well as the sexual, body.
The virtues of vice
Authors: Boryczka Jocelyn M.
Published: March 2006

Virtue and vice remain at the margins of feminist conceptual analysis although both establish a dualism that denies women full citizenship. To make this argument, this analysis explores the historical case of the Lowell mill girls – the first nearly all-female labour force in the United States between 1826 and 1850. Their public debate illustrates how virtue aligns some women with the economic and political status quo while society affiliates those who challenge its dominant beliefs with vice. This moral location reveals the ‘virtues of vice’ or the political benefits that women may derive from vice which places them outside traditional moral and political discourse, enabling them to question existing moral paradigms, consider alternatives, and politically organize against the status quo. As such, the Lowell mill girl debate can inform contemporary feminist theory by raising serious questions about virtue and suggesting how vice opens up a critical space for ideological innovation, referred to here as a moral middle ground, that may result in a more democratic, feminist ethics.
Educational Leadership and the Challenge of Diversity
Authors: Gunter Helen M.
Published: March 2006

Diversity is a normal feature of humanity but it is constructed as positive or negative dependent on political, economic and social structures. How organizations, not least those in the public sector, handle this is the main aim of this article. The emphasis is on surveying how these matters are being approached and how we might as a field develop an agenda for study and practice. Of particular note is the current emphasis on capabilities, and what this means for a field that has traditionally drawn on rational knowledge that has emphasized unity and control.
Effect of test temperature on tensile properties of α/β brass containing lead
Authors: Kashyap B. P. , Verma S. , Mandlik P. , Kumar N. , Toppo S. P.
Published: March 2006

Tensile specimens of α/ β brass with the composition of Zn–56·9Cu–3·5Pb (wt-%) were deformed to failure at constant initial strain rates ϵ of 1 × 10−4 and 1 × 10−2 s−1 in the temperature range of 297−973 K. Unlike the superplastic behaviour of α/ β brass, this material was found to exhibit much lower ductility with the minimum values being 11·2 and 16·2% around 873 K at ϵ=1 × 10−4 s− 1 and 1 × 10−2 s−1 respectively. This behaviour is attributed to the liquid metal embrittlement owing to the presence of lead in this material. As biased by the embrittling effect, rather than thermally activated deformation process, the evaluation of ductility δ and strain rate sensitivity index m as a function of temperature suggests an anomalous relationship between δ and m.
Microstructural investigation on antifriction characteristics of self-lubricating copper hybrid composite
Authors: Zhan Y. Z. , Shi X. B. , Xie H. F.
Published: March 2006

Owing to good antifriction properties and high wear resistance, copper hybrid composites reinforced with hard ceramic particles and solid lubricant components are regarded as promising materials for applications in sliding electrical contacts. The present work investigates the antifriction mechanism of a (SiC+Gr)/Cu composite from a microstructural viewpoint, so as to assist the development and application of this material. A graphite rich tribolayer formed on the worn surface was responsible for good tribological properties of the composites. Testing results showed that nanoparticles of graphite were involved in a mechanically mixing process by adhering to both the other wear debris and the two contacting surfaces, thereby developing a solid lubricant tribolayer. The nanographite to nanographite contacting mode, formed between the composite and the counterface, significantly improved wear resistance and friction stability. The forming and failure process of the graphite rich tribolayer was studied. A mechanism has been developed based on the experimental results.
Development of tubular transition joints of aluminium/stainless steel by deformation diffusion bonding
Authors: Bhanumurthy K. , Fotedar R. K. , Joyson D. , Kale G. B. , Pappachan A. L. , Grover A. K. , Krishnan J.
Published: March 2006

Joining of aluminium and aluminium alloys to stainless steel is frequently required in many low temperature and nuclear applications. The present study describes a relatively new method of bonding these materials by suitably combining the deformation bonding and solid state bonding techniques for joining tubular assemblies. The stainless steel and aluminium specimens have been machined to form cylindrical tube specimens and special grooves have been machined on the inner diameter (ID) side of the stainless steel specimens. The polished stainless steel specimens have been coated with Ni, Cu and Ag in sequence on these grooves and Zn, Cu and Ag in sequence on the outer diameter side (OD) of the aluminium. The specimens have been bonded in hot vacuum press using argon as a pressurising medium and allowing the aluminium to plastically flow into the stainless steel grooves. Metallurgical investigation of the diffusion bonded specimen carried out at 315°C for 4 h indicated excellent bonding and total absence of the intermetallic compounds in the reaction zone. The joints bonded at this temperature indicated that the bond strength was superior to that of the base material of aluminium and the bending angle was >40°. The paper presents the details of this technique and also methodology adopted for optimising the bonding parameters.
Analysis of ridging in three ferritic stainless steel sheets
Authors: da Costa Viana C. S. , Pinto A. L. , Candido F. S. , Matheus R. G.
Published: March 2006

In the present work, three types of ferritic stainless steel sheets AISI 430A (16%Cr), AISI 430E (16%Cr, 0·36%Nb) and AISI 434 (16%Cr, 1%Mo), known to display different ridging behaviours, were characterised in both microstructure and texture using optical metallography and electron backscatter diffraction techniques. It was concluded that surface microridging is a result of the differential plastic behaviour of {111}〈 uvw〉 and {001}〈 uvw〉 grain colonies existing in the sheet; severe ridging (undulations) is a consequence of through thickness texture and microstructure inhomogeneities that lead to grain buckling under internal compressive stresses.
Effect of temperature on reduction of nanocrystalline Fe2O3 into metallic iron
Authors: Bahgat M. , Khedr M. H. , Nasr M. I. , Sedeek E. K.
Published: March 2006

The synthesis of ultrafine magnetic material with large saturation magnetisation and high coercivity has received much attention, owing to its wide applications. The reduction of nanocrystalline Fe2O3 into metallic iron was studied. The iron oxide precursor was synthesised by thermal evaporation of iron acetate and then pressed into cylindrical shape compacts before being fired at 500°C for 1 h in a muffle furnace.

The prepared nanocrystalline Fe2O3 was characterised using X-ray diffraction analysis technique, reflected light microscope and scanning electron microscope. The reduction behaviour of nanocrystalline Fe2O3 in hydrogen atmosphere at 450–600°C has been studied using thermogravimetric techniques. The reduction rate is controlled initially by the interfacial chemical reaction mechanism, while the solid state diffusion is the rate controlling mechanism at final stages. The reduction temperature has a great effect on physicochemical properties of produced metallic iron during reduction of nanocrystalline Fe2O3. Metallic iron was formed in nanosized grains of 100–200 nm, while grain growth and highly coalescence were observed at reduction temperatures higher than at firing temperatures. Diluted magnetic nanoiron metal was formed with Hc ranged from 25 to 94 Oe, Br from 0·5 to 1·8 emu g−1 and Bs from 24·5 to 41·4 emu g−1.
Microstructural characterisation and corrosion behaviour of laser cladded Al–12Si alloy onto magnesium AS41/carbon fibre composite
Authors: Bakkar A. , Galun R. , Neubert V.
Published: March 2006

The quality and properties of laser clad layers are dependent on the microstructure and properties of the interfaces with the substrate. The present paper reports, in details, on the characterisation of microstructure of the coating and interfacial layers evolved as a result of the CO2 laser remelting of previously plasma sprayed Al–12Si alloy onto C short fibres reinforced AS41–Mg composite. Scanning electron microscopy (SEM), wavelength dispersive X-ray (WDX) analysis and X-ray diffraction (XRD) were employed to identify the phases arising in the interfacial layers. The latter are composed mainly of Mg17Al12 and Mg2Si phases. XRD was conducted on the clad layers at different distances from the interface. At the same layers, the potentiodynamic polarisation in sodium chloride solution was measured and it was found that as the Mg content increases in the clad coating, the corrosion resistance decreases. However, the corrosion current of the clad coating is around two orders of magnitude lower than that of the C/Mg composite.
Effects of substrate material and annealing temperature on morphology of zinc oxide films
Authors: Vaezi M. R. , Sadrnezhaad S. K.
Published: March 2006

A two stage chemical deposition (TSCD) technique is used to produce ZnO films on quartz glass (QG), soda lime glass (SLG) and high purity alumina (HPA) from an aqueous solution of zinc complex. The effects of the substrate material on the chemical composition and morphology of the deposited layer are investigated. The effects of different annealing temperatures (180, 300, 500 and 800°C) on the morphology and orientation of the ZnO crystallites are also determined. X-ray diffraction diffractograms show that above 300°C, the intensity of (002) peak considerably decreases with increasing temperature. Results indicate that changing the substrate from QG to SLG does not significantly influence the chemical composition of the deposited layer. These variations can be attributed to different factors including (a) physorption of cold complex solution, (b) growth behaviour of the nuclei forming on the substrate and (c) the surface energy of the substrate. Owing to the existence of the morphological differences bound to the molecular nature of the substrate, properties of the coatings are found not to be the same. HPA substrate causes clustering of the ZnO crystallites, while QG and SLG substrates do not distinguishably show this effect. Observations show that clustering is intensified by annealing at temperatures > 180°C.
Hydrotalcite mineral stabilisation of titanium dioxide photocatalysed degradation of unplasticised polyvinylchloride
Authors: Martin G. P. , Robinson A. J. , Worsley D. A.
Published: March 2006

Hydrotalcite additions (up to 10 PHR) are shown to stabilise unplasticised polyvinylchloride (UPVC) against TiO2 photocatalysed degradation. Without stabilisation, hydrogen chloride, produced through dehydrochlorination, catalyses the TiO2 sensitised degradation after a set period of reaction leading to an increase in rate from 13 to 32 μmol m−2 min−1. Hydrotalcite removes chloride by anion exchange releasing carbonate ions in the PVC removing this autocatalytic pathway.
Non-isothermal grain growth in metals and alloys
Authors: Mishra S. , DebRoy T.
Published: March 2006

A large portion of the previous research on grain growth has been focused on isothermal conditions and excellent reviews on this topic are available in the literature. However, most of the materials processing operations such as casting, rolling and welding take place under non-isothermal conditions. Grain growth in materials under significant spatial and temporal variation of temperature exhibits many important special characteristics. The present paper critically examines these special features of grain growth in several important materials processing operations. Various experimental and theoretical approaches used to study grain growth in non-isothermal systems are examined and compared. The classical isothermal grain growth theories are reviewed, because they are sometimes applied to non-isothermal systems by incorporating thermal history in the calculations. Various numerical techniques and their applications to non-isothermal systems are also examined and compared. Finally, progress made in understanding non-isothermal grain growth in metals and alloys is summarised and several areas of future research are identified. This review is targeted towards an audience of materials scientists and engineers interested in various materials processing operations under non-isothermal conditions.
Deformation texture and microtexture developments in a cold rolled single phase hexagonal Zircaloy 2
Authors: Kiran Kumar M. , Vanitha C. , Samajdar I. , Dey G. K. , Tewari R. , Srivastava D. , Banerjee S.
Published: March 2006

A single phase hexagonal close packed Zircaloy 2 was cold deformed to different reductions by laboratory rolling. Systematic characterisations of the structural developments were carried out. Bulk texture developments were gradual, strongest developments being noticed at the highest strain. Although formation of well defined deformation fibre(s) could not be identified, overall developments in deformation texture were best captured through Taylor type models incorporating only prismatic slip. Strain localisations were observed as single or double walled dislocation structures at approximately 45 and 60° to the rolling direction. Such strain localisations were always associated with significant lattice reorientations or misorientation developments. Relative softening in lattice strain, observed at the higher reductions, can possibly be explained by the appearance of extensive strain localisations and the associated concurrent local dynamic recovery. The grains or orientations with dominant presence of strain localisations could be indirectly related to negative textural softening.
A multivariate prediction model for microarray cross-hybridization
Authors: Chen Yian A , Chou Cheng-Chung , Lu Xinghua , Slate Elizabeth H , Peck Konan , Xu Wenying , Voit Eberhard O , Almeida Jonas S
Published: March 2006

Background

Expression microarray analysis is one of the most popular molecular diagnostic techniques in the post-genomic era. However, this technique faces the fundamental problem of potential cross-hybridization. This is a pervasive problem for both oligonucleotide and cDNA microarrays; it is considered particularly problematic for the latter. No comprehensive multivariate predictive modeling has been performed to understand how multiple variables contribute to (cross-) hybridization.

Results

We propose a systematic search strategy using multiple multivariate models [multiple linear regressions, regression trees, and artificial neural network analyses (ANNs)] to select an effective set of predictors for hybridization. We validate this approach on a set of DNA microarrays with cytochrome p450 family genes. The performance of our multiple multivariate models is compared with that of a recently proposed third-order polynomial regression method that uses percent identity as the sole predictor. All multivariate models agree that the 'most contiguous base pairs between probe and target sequences,' rather than percent identity, is the best univariate predictor. The predictive power is improved by inclusion of additional nonlinear effects, in particular target GC content, when regression trees or ANNs are used.

Conclusion

A systematic multivariate approach is provided to assess the importance of multiple sequence features for hybridization and of relationships among these features. This approach can easily be applied to larger datasets. This will allow future developments of generalized hybridization models that will be able to correct for false-positive cross-hybridization signals in expression experiments.
A simple method for assessing sample sizes in microarray experiments
Authors: Tibshirani Robert
Published: March 2006

Background

In this short article, we discuss a simple method for assessing sample size requirements in microarray experiments.

Results

Our method starts with the output from a permutation-based analysis for a set of pilot data, e.g. from the SAM package. Then for a given hypothesized mean difference and various samples sizes, we estimate the false discovery rate and false negative rate of a list of genes; these are also interpretable as per gene power and type I error. We also discuss application of our method to other kinds of response variables, for example survival outcomes.

Conclusion

Our method seems to be useful for sample size assessment in microarray experiments.
VANTED: A system for advanced data analysis and visualization in the context of biological networks
Authors: Junker Björn H , Klukas Christian , Schreiber Falk
Published: March 2006

Background

Recent advances with high-throughput methods in life-science research have increased the need for automatized data analysis and visual exploration techniques. Sophisticated bioinformatics tools are essential to deduct biologically meaningful interpretations from the large amount of experimental data, and help to understand biological processes.

Results

We present VANTED, a tool for the v isualization and a nalysis of n etworks with related e xperimental d ata. Data from large-scale biochemical experiments is uploaded into the software via a Microsoft Excel-based form. Then it can be mapped on a network that is either drawn with the tool itself, downloaded from the KEGG Pathway database, or imported using standard network exchange formats. Transcript, enzyme, and metabolite data can be presented in the context of their underlying networks, e. g. metabolic pathways or classification hierarchies. Visualization and navigation methods support the visual exploration of the data-enriched networks. Statistical methods allow analysis and comparison of multiple data sets such as different developmental stages or genetically different lines. Correlation networks can be automatically generated from the data and substances can be clustered according to similar behavior over time. As examples, metabolite profiling and enzyme activity data sets have been visualized in different metabolic maps, correlation networks have been generated and similar time patterns detected. Some relationships between different metabolites were discovered which are in close accordance with the literature.

Conclusion

VANTED greatly helps researchers in the analysis and interpretation of biochemical data, and thus is a useful tool for modern biological research. VANTED as a Java Web Start Application including a user guide and example data sets is available free of charge at http://vanted.ipk-gatersleben.de.
Genome-wide analysis of core promoter elements from conserved human and mouse orthologous pairs
Authors: Jin Victor X , Singer Gregory AC , Agosto-Pérez Francisco J , Liyanarachchi Sandya , Davuluri Ramana V
Published: March 2006

Background

The canonical core promoter elements consist of the TATA box, initiator (Inr), downstream core promoter element (DPE), TFIIB recognition element (BRE) and the newly-discovered motif 10 element (MTE). The motifs for these core promoter elements are highly degenerate, which tends to lead to a high false discovery rate when attempting to detect them in promoter sequences.

Results

In this study, we have performed the first analysis of these core promoter elements in orthologous mouse and human promoters with experimentally-supported transcription start sites. We have identified these various elements using a combination of positional weight matrices (PWMs) and the degree of conservation of orthologous mouse and human sequences – a procedure that significantly reduces the false positive rate of motif discovery. Our analysis of 9,010 orthologous mouse-human promoter pairs revealed two combinations of three-way synergistic effects, TATA-Inr-MTE and BRE-Inr-MTE. The former has previously been putatively identified in human, but the latter represents a novel synergistic relationship.

Conclusion

Our results demonstrate that DNA sequence conservation can greatly improve the identification of functional core promoter elements in the human genome. The data also underscores the importance of synergistic occurrence of two or more core promoter elements. Furthermore, the sequence data and results presented here can help build better computational models for predicting the transcription start sites in the promoter regions, which remains one of the most challenging problems.