bluuebunny/crossref_metadata_2025 huggingface dataset:
A Work-Centered Approach for Setting Passing Scores on Performance-Based Assessments
Authors: McKinley Danette Waller , Boulet John R. , Hambleton Ronald K.
Published: August 2005

Standardized patient examinations are being used for high-stakes decisions (e.g., graduation, licensure, and certification) with growing frequency. Concurrently, research on methods to determine the passing score for these types of performance-based assessments has increased. A wide variety of approaches have been considered in the past several years, many based on traditional techniques developed for use with multiple-choice examinations. More and more, techniques that center on review of examinee work have been employed, often resulting in the establishment of defensible, reproducible standards. The purpose of this article is to describe and evaluate a work-centered approach for determining the passing score for a performance-based assessment of clinical skills. A description of an approach to set passing scores that involves expert review of examinee work is presented. Application and evaluation of the method are illustrated using examination materials obtained from a high-stakes certification assessment.
Isomeric Biphenyl Polyimides. (II) Glass Transitions and Secondary Relaxation Processes
Authors: Kochi Masakatsu , Chen Chunhai , Yokota Rikio , Hasegawa Masatoshi , Hergenrother Paul
Published: August 2005

Dynamic mechanical analysis was performed on a series of the isomeric polyimides (PIs) made from the reaction of s-, a-, and i-BPDA each with 4,4′-ODA, 3,3′-ODA, 1,3,3-APB and 1,4,4-APB. The glass transitions (T g s) moved towards higher temperatures in the order of s-, a-, and i-BPDA for the para diamine-based PIs whereas the T g values showed little change for meta diamine-based PI regardless of the BPDA isomer. Conversely, the temperature of the β relaxation process increased in the order of i-, a-, and s-BPDA with any diamine. These behaviors can be interpreted in terms of the steric hindrance effects due to the configuration of BPDA isomers and diamines.
Synthesis of High Molecular Weight Polybenzoxazoles in Polyphosphoric Acid and Investigation of their Hydrolytic Stability under Acidic Conditions
Authors: Kim Young Jun , Einsla Brian R. , Tchatchoua Charles N. , Mcgrath James E.
Published: August 2005

Studies on the synthesis of high molecular weight polybenzoxazoles (PBOs) in polyphosphoric acid (PPA) and investigations of their hydrolytic stability in aqueous methanesulfonic acid are described. The polymerization of PBOs based upon 2,2′-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane (6FAP) and 4,4′-oxydibenzoic acid (ODBA) was investigated as a function of the percentage of P2 O5 content in PPA, polymerization temperature, percentage monomer (total weight of monomers/weight of monomers plus PPA), and reaction time. It was found that the percentage of P2 O5 content was the most important polymerization variable and that PPA with more than 85% P2 O5 content was required to achieve high molecular weight PBOs. Hydrolytic stability of PBOs prepared from selecting 6FAP and either ODBA, isophthalic acid (IA), or terephthalic acid (TA) was investigated by solution viscosity measurements, 1 HNMR and FTIR spectroscopy. The hydrolysis experiments were conducted in aqueous methanesulfonic acid solutions at room temperature, 50, and 80° C. The 6FAP/ODBA PBO showed improved stability over time with respect to the 6FAP-IA and 6FAP-TA PBOs, which may be due to the decreased electrophilicity of the carbon atom of the oxazole ring. But, the inherent viscosities of all the PBOs decreased over time and 1 H-NMR and FTIR spectroscopic evidence for chain scission was obtained. Benzoxazole model compounds, 2,2′-Bis(2-phenylbenzoxazol-6-yl)hexafluoropropane, 2,2′-bis[2-(4-phenoxyphenyl)benzoxazol6-yl]hexafluoropropane, were synthesized from selecting 6FAP and ether 4-phenoxybenzoic acid or benzoic acid in N -cyclohexylpyrrolidinone. Nuclear magnetic resonance spectroscopic data provided direct evidence of hydrolysis of oxazole functional groups.
Reinforcement of Poly(ethylene terephthalate) Fibers with Polyhedral Oligomeric Silsesquioxanes (POSS)
Authors: Zeng J. , Kumar S. , Iyer S. , Schiraldi David A. , Gonzalez R. I.
Published: August 2005

Poly(ethylene terephthalate) (PET)-based composite fibers were prepared by melt spinning three types of PET/polyhedral oligomeric silsesquioxane (POSS) composites. These composites were made by either melt blending POSS with PET at 5 wt% loading level (non-reactive POSS and silanol POSS) or by in-situ polymerization with 2.5 wt% reactive POSS. Significant increases in tensile modulus and tensile strengths were achieved in PET fibers with non-reactive POSS at room temperature. The hightemperature modulus retention was found to be much better for PET/silanol POSS fiber when compared to that of control PET. Although other PET/POSS nancomposite fibers tested did not show this high retention of modulus at elevated temperatures, PET/isooctylPOSS nanocomposite fibers did show increased modulus at elevated temperature compared to that of PET. Higher compressive strengths, compared to PET fibers, were observed for all three nanocomposite fibers. Gel permeation chromatography measurement suggested that there is no significant change in molecular weight during preparation of PET/POSS nanocomposites. SEM observations suggest that there is no obvious phase separation in any of the three PET/POSS systems. Crystallization behavior and thermal stability of the composite were also studied. The fiber spinning and mechanical performance with 10 and 20 wt% of trisilanolisooctyl POSS2 were also investigated1 the composites with higher concentrations of this nanofiller can be spun without any difficulty. At room temperature, the fiber tensile modulus increased steadily with the POSS concentration while fiber tensile strength showed no significant change. The elongation at break decreased significantly with increasing of POSS concentration. The high-temperature moduli of PET/POSS nanocomposite fibers were found to be rather variable, likely due to the modest compatibility between filler and polymers, which can lead to structural anisotropy within the composite.
Buckling and Postbuckling Characteristics of the Superelastic SMA Columns – Numerical Simulation
Authors: Rahman Muhammad Ashiqur , Qiu Jinhao , Tani Junji
Published: August 2005

Numerical simulation has been carried out to analyze several unique buckling and postbuckling behaviors of superelastic shape memory alloy (SMA) columns observed from experimental evidences. Comparison of the experimental critical load with analytical predictions verifies the fact that physical nonlinearity should be taken into account to comprehensively analyze the buckling behaviors of SMA columns. Thus, based on the nonlinear stress–strain relations as well as the large deformation theory, the load–deformation curves of the columns during a complete loading–unloading cycle have been predicted by using the FEM code ANSYS. Simulation has also been performed for the stainless steel (SUS304) columns. The total strain distributions in the column materials have been calculated at different states of loading. Precise and quantitative analyses of the results verify that the unique behaviors of the SMA columns could be attributed to the special nature of the stress–strain curves. It is found that the slender SMA column buckles in the austenite phase. Due to SMA's high strength for large strains, the slender columns can sustain the load with a very small change in magnitude for the postbuckling compression. A special method has been devised to simulate the unique unloading path of the slender superelastic SMA columns and its usefulness has been demonstrated. It has been found that defining a few intermediate unloading curves between the actual loading and unloading curves can help to minimize the stress discontinuity at the beginning of unloading. Simulation results also verify that because of the elastic shape recovery of the buckled slender SMA columns, the load increases when they are unloaded.
Vibration Control of Composite Smart Structures by Feedforward Adaptive Filter in Digital Signal Processor
Authors: Yang S. M. , Sheu G. J. , Liu K. C.
Published: August 2005

Intelligent structures with built-in piezoelectric sensors and actuators have been found to be preferable in vibration control. However, it is difficult to model the uncertainties of interfaces between the composite lamina and the embedded sensor/actuator. This article presents an adaptive filter design for system dynamics identification of composite laminated smart structures. A feedforward adaptive controller based on an adaptive filter with dynamic convergence is also developed for vibration suppression. Both the adaptive filter for system identification and the adaptive controller for vibration suppression are implemented in TMS320C32 digital signal processor for real-time applications. Experimental verifications show that the adaptive control is superior to active damping control and it is effective and robust to vibration suppression of smart structures.
Test-Retest Reliability of Standard and Emotional Stroop Tasks
Authors: Strauss Gregory P. , Allen Daniel N. , Jorgensen Melinda L. , Cramer Stacey L.
Published: August 2005

Previous studies have examined the reliability of scores derived from various Stroop tasks. However, few studies have compared reliability of more recently developed Stroop variants such as emotional Stroop tasks to standard versions of the Stroop. The current study developed four different single-stimulus Stroop tasks and compared test-retest reliabilities. The four Stroop tasks included two standard Stroop tasks (color-word and picture-word) as well as two emotional Stroop tasks (color-word and picture-word). The four Stroop tasks were administered on two occasions, separated by 1 week, to 28 undergraduate students. Test-retest reliability coefficients were high for standard and emotional Stroop tasks when reliability was measured using response latencies alone. However, test-retest coefficients were unacceptably low when reliability estimates were calculated using difference scores. The findings have important implications for clinical and experimental use of standard and emotional Stroop tasks.
Using Structural Analysis of Social Behavior (SASB) Measures of Self- and Social Perception to Give Interpersonal Meaning to Symptoms
Authors: Erickson Thane M. , Pincus Aaron L.
Published: August 2005

Current symptom-based diagnosis, although important, lacks theoretical underpinning that might give meaning to psychiatric symptoms. The structural analysis of social behavior (SASB) fills this void, operationalizing interpersonal theory for investigation of relational aspects of psychopathology. To provide an example of how SASB may be utilized to this end, participants with (n = 40) and without (n = 40) uncontrollable worry and anxiety completed SASB Intrex Questionnaires to explore self-perceptions and perceptions of strangers in a social interaction task. Based on SASB principles and past research on familial factors in childhood anxiety, it was hypothesized that self- and other perceptions would discriminate participant groups along the lines of disrupted and normal attachment. To demonstrate the versatility of SASB, analyses incorporated indexes of varying specificity. Largely, results supported predictions, suggesting the sensitivity of SASB Intrex to assess social perceptions even in a first-meeting context, extending its known possible uses.
The Construct Validity of the Stanford-Binet 5 Measures of Working Memory
Authors: Pomplun Mark , Custer Michael
Published: August 2005

This study examines the validity of the measures of verbal and nonverbal working memory on the Stanford-Binet Fifth Edition (SB5). The validity evidence included Rasch-based, criterion-referenced item mapping, correlations with other clinical measures of memory, and prediction of reading and mathematics scores. The item mapping clearly demonstrates a parallel between increasing item difficulty and a progression of item characteristics that placed increasing demands on verbal and nonverbal working memory. The higher correlations of the SB5 verbal and nonverbal working memory subtests with other measures of verbal and nonverbal memory, respectively, and lower correlations with nonverbal and verbal memory measures, respectively, clearly show convergent and divergent validity. The higher correlations between SB5 verbal working memory and reading skills and between SB5 nonverbal memory and mathematics skills are consistent with past research.
Revisiting the Factor Structure of the WAIS-R
Authors: Gignac Gilles E.
Published: August 2005

Past attempts to model via confirmatory factor analysis (CFA) the Wechsler Adult Intelligence Scale-Revised (WAIS-R) intersubtest covariation have used an oblique factor or a higher order modeling approach. The attempts have failed to yield adequate model fit, based on current CFA recommendations. Using the WAIS-R standardization data, it is demonstrated that the WAIS-R can be better conceptualized as measuring a first-order general factor and three orthogonal group-level factors. The results are discussed in relation to Verbal and Performance Intelligence scoring and failed attempts to find relationships between VIQ/PIQ difference scores and external criteria. Because Arithmetic and Digit Span did not share any variance with the other VIQ subtests, independent of General Intelligence, clinicians should reconsider interpreting a VIQ score that includes information from Arithmetic and Digit Span in nonclinical populations. Researchers are encouraged to model intelligence factors as nested factor models, considering their superior model fit, and the increased clarity in the interpretations of relationships between IQ indices and criteria.
Effects of different teaching styles on the teacher behaviours that influence motivational climate and pupils' motivation in physical education
Authors: Morgan Kevin , Kingston Kieran , Sproule John
Published: August 2005

This study investigated the effects of different teaching styles on the teaching behaviours that influence motivational climate and pupils' cognitive and affective responses in physical education. Four (two male, two female) initial teacher education (ITE) students and 92 pupils (47 boys, 45 girls), from two schools in the UK, participated in the study. The student teachers were filmed teaching three lessons each, adopting a different teaching style for each. The teaching styles (command/practice, reciprocal and guided discovery) were selected from Mosston and Ashworth's (2002) spectrum. The teaching behaviours were measured using a computer-coding system devised for Ames's guidelines on how to create a mastery climate. Focus groups were conducted to examine the pupils' cognitive and affective responses. Results revealed that the reciprocal and guided discovery styles resulted in more mastery and less performance-focused teaching behaviours and more adaptive cognitive and affective responses than the command/practice style.
Trainee teachers' perceptions of job advertisements in England with regard to gender and physical education
Authors: Stidder Gary
Published: August 2005

This article explores the ways in which job advertisements for physical education (PE) teachers in England perpetuate stereotypical notions of gender and how this can affect recruitment within the profession. It assesses the extent to which the 'gendered' vocabulary used in job advertisements can potentially influence the decision-making of women and men seeking secondary school PE teaching posts in England and the implications for professional practice. Discussions with 32 postgraduate trainee teachers were carried out at a teacher training institution in the south of England and focused on their perceptions of 30 job advertisements for PE teachers. The data showed that male and female trainees often felt that employment opportunities for men and women in PE were constrained by the 'gendered' vocabulary included within advertisements and therefore had some impact on their decisions when considering whether to apply for particular posts. Given the dominance of sex-differentiated patterns of staffing within PE in the United Kingdom, the study raises questions related to employment rights of women and men and assesses the extent to which vocabulary can deter or prevent potential applicants from applying for particular teaching posts based on their sex. Likewise, this study considers whether PE job advertisements, particularly for senior PE management positions, can be justified on the grounds of sex within the framework of equal opportunities.
From first-person inquiry to radical social action
Authors: Nolan Patrick
Published: August 2005

A successful social entrepreneurship project in Dublin, Ireland, Fastrack into Information Technology (FIT) forms the backdrop for this article on the value, influence and significance of a dedicated first-person inquiry. The work makes the connections between the early poverty experiences of the author, a subsequent business career of high achievement and this followed by a deliberate choice to sell his assets and to commit himself to the resolution of serious social problems. Underpinning this new orientation is a faith-based spirituality reflected in the Spiritual Exercisesof St. Ignatius (Founder of the Jesuits). The article explores the close relationship between these Spiritual Exercisesand first-person inquiry practice. In tracing their influence over a time span of quarter of a century, it places first-person inquiry appropriately at the core of the activity while, at the same time, describing the organic links which forge growthful outcomes in second and third-person arenas. With a descriptive image of the bloc of influence which make up the FIT project – government, industry and local communities – and emphasizing its co-creative nature, the work concludes with a vision for the next stage. The realisation of this vision will continue to see first-person inquiry in a central and pivotal role.
'Sharpening the instrument'
Authors: Mann Pete
Published: August 2005

This article, drawing on self-reflective experiential research within reciprocally inquiring relationships as expounded by Heron, explores learning derived from an innovative psycho-therapeutic approach. Pesso-Boyden System Psychomotor (PBSP) links mind/body in its philosophy and practice. Two domains of inquiry are reported. In the first, I as chief storyteller map three psychotherapists' reflective learning of PBSP. In the second, I explore how my practice of teaching and supervising and dealing with colleagues at a university is informed by my own PBSP development. Quality criteria of experiential psychological growth and of experiential psychological research are used, respectively, to consider both the content of the learning narrated and the process of the way it has been realized and communicated. The article attempts to 'show data' as well as interrelate their meanings, more than simply 'tell about' data. In this sense, the writing approach is analogically congruent with the themes presented.
Study of Polypropylene Morphology Obtained from Blown and Cast Film Processes: Initial Morphology Requirements for Making Porous Membrane by Stretching
Authors: Sadeghi F. , Ajji A. , Carreau P. J.
Published: August 2005

Four different polypropylene (PP) resins are extruded using the tubular blown and cast film processes. The resin morphology is observed by SEM and the effect of extrusion processing variables on the morphology is investigated. Melt rheological experiments are also carried out to characterize the polymer melts. It has been found that the molecular weight distribution and the chain structure as well as the processing conditions have important effects on the morphology. Efforts have been focused on developing a row-nucleated morphology from PPs through the control of processing conditions. The possibility of generating a porous membrane from the initial row-nucleated morphology using a stretching technique is evaluated. It has been found that the initial lamellae arrangement of the precursor films and the stretching conditions play a significant role in obtaining a porous structure.
Surface Haze and Surface Morphology of Blown Film Compositions
Authors: Patel Rajen , Ratta Varun , Saavedra Pepe , Li Jing
Published: August 2005

Reduction in surface haze is a very attractive way to improve the optical properties of most polyolefin films. This route becomes very viable for coextruded multilayer films where the inner layers may be utilized to provide the desired mechanical properties, such as high modulus, controlled shrinkage, and good tear strength while the outer 'skin' layers are utilized to give low surface and total haze values. This study summarizes the effect on surface haze of various such 'skin' layer compositions with a broader goal to produce high clarity and high modulus multilayer blown films. The surface roughness of multilayer films is measured using atomic force microscopy (AFM) and is directly correlated to the measured surface haze of the films.
Exploring ‘an area of outstanding unnatural beauty’: a treasure hunt around King’s Cross, London
Authors: Battista Kathy , LaBelle Brandon , Penner Barbara , Pile Steve , Rendell Jane
Published: August 2005

In this paper we describe the Pleasure of treasure treasure hunt around London’s King’s Cross area. The pleasure of treasure was devised as a response to Richard Wentworth’s exhibition An area of outstanding unnatural beauty, November 2002. Richard Wentworth sought to explore the character of King’s Cross by creating an exhibition space that would provide somewhere both where the overlooked and hidden histories of King’s Cross could be gathered together and also where people from the King’s Cross area could engage with activities that had been lost or overlooked. Similarly, The pleasure of treasure sought to take people around the area with a view to exploring its histories and oddities. More than this, it hoped to open up the area to fresh eyes, capable of seeing the secret treasures that lay there. In keeping with Wentworth’s project, the beauty of King’s Cross lay not only in the process of exploration but also in the chance encounters (of various kinds) that sometimes surprise and sometimes disappoint.
folded gastrulation, cell shape change and the control of myosin localization
Authors: Dawes-Hoang Rachel E. , Parmar Kush M. , Christiansen Audrey E. , Phelps Chris B. , Brand Andrea H. , Wieschaus Eric F.
Published: August 2005

The global cell movements that shape an embryo are driven by intricate changes to the cytoarchitecture of individual cells. In a developing embryo,these changes are controlled by patterning genes that confer cell identity. However, little is known about how patterning genes influence cytoarchitecture to drive changes in cell shape. In this paper, we analyze the function of the folded gastrulation gene (fog), a known target of the patterning gene twist. Our analysis of fog function therefore illuminates a molecular pathway spanning all the way from patterning gene to physical change in cell shape. We show that secretion of Fog protein is apically polarized, making this the earliest polarized component of a pathway that ultimately drives myosin to the apical side of the cell. We demonstrate that fog is both necessary and sufficient to drive apical myosin localization through a mechanism involving activation of myosin contractility with actin. We determine that this contractility driven form of localization involves RhoGEF2 and the downstream effector Rho kinase. This distinguishes apical myosin localization from basal myosin localization, which we find not to require actinomyosin contractility or FOG/RhoGEF2/Rho-kinase signaling. Furthermore, we demonstrate that once localized apically, myosin continues to contract. The force generated by continued myosin contraction is translated into a flattening and constriction of the cell surface through a tethering of the actinomyosin cytoskeleton to the apical adherens junctions. Our analysis of fog function therefore provides a direct link from patterning to cell shape change.
Fgf8 drives myogenic progression of a novel lateral fast muscle fibre population in zebrafish
Authors: Groves Julie A. , Hammond Christina L. , Hughes Simon M.
Published: August 2005

Fibroblast growth factors (Fgfs) have long been implicated in regulating vertebrate skeletal muscle differentiation, but their precise role(s) in vivo remain unclear. Here, we show that Fgf8 signalling in the somite is required for myod expression and terminal differentiation of a subset of fast muscle cells in the zebrafish lateral somite. In the absence of Fgf8, lateral somite cells transiently express myf5 but fail to make muscle and remain in a dermomyotome-like state characterised by pax3 and meox expression. Slow muscle fibres form and commence normal migration in the absence of Fgf8, but fail to traverse the expanded undifferentiated lateral somite. The Fgf8-independent residual population of medial fast muscle fibres is not Hedgehog dependent. However, Fgf8-independent medial fast muscle precursors are lacking in floatinghead mutants,suggesting that they require another ventral midline-derived signal. We conclude that Fgf8 drives terminal differentiation of a specific population of lateral muscle precursor cells within the early somite.
The evolutionary history of placodes: a molecular genetic investigation of the larvacean urochordate Oikopleura dioica
Authors: Bassham Susan , Postlethwait John H.
Published: August 2005

The evolutionary origin of vertebrate placodes remains controversial because divergent morphologies in urochordates, cephalochordates and vertebrates make it difficult to recognize organs that are clearly homologous to placode-derived features, including the olfactory organ, adenohypophysis,lens, inner ear, lateral line and cranial ganglia. The larvacean urochordate Oikopleura dioica possesses organs that morphologically resemble the vertebrate olfactory organ and adenohypophysis. We tested the hypothesis that orthologs of these vertebrate placodes exist in a larvacean urochordate by analyzing the developmental expression of larvacean homologs of the placode-marking gene families Eya, Pitx and Six. We conclude that extant chordates inherited olfactory and adenohypophyseal placodes from their last common ancestor, but additional independent proliferation and perhaps loss of placode types probably occurred among the three subphyla of Chordata.
Regulating the dynamics of EGF receptor signaling in space and time
Authors: Shilo Ben-Zion
Published: August 2005

The epidermal growth factor receptor (EGFR) signaling cascade represents one of the cardinal pathways that transmits information between cells during development in a broad range of multicellular organisms. Most of the elements that constitute the core EGFR signaling module, as well as a variety of negative and positive modulators, have been identified. Although this molecular pathway is utilized multiple times during development, the spatial and temporal features of its signaling can be modified to fit a particular developmental setting. Recent work has unraveled the various mechanisms by which the EGFR pathway can be modulated.
Fibulin-1C and Fibulin-1D splice variants have distinct functions and assemble in a hemicentin-dependent manner
Authors: Muriel Joaquin M. , Dong Chun , Hutter Harald , Vogel Bruce E.
Published: August 2005

Fibulins are a family of extracellular glycoproteins associated with basement membranes and elastic fibers in vertebrates. Conservation of the fibulin-1 gene throughout metazoan evolution includes fibulin-1C and fibulin-1D alternate splice variants, although little is known about variant specific functions that would justify this striking structural conservation. We have therefore investigated the structure, localization and loss-of-function phenotype specific to both fibulin-1 variants in C. elegans. We find that fibulin-1C has specific roles during pharynx,intestine, gonad and muscle morphogenesis, being required to regulate cell shape and adhesion, whereas fibulin-1D assembles in flexible polymers that connect the pharynx and body-wall-muscle basement membranes. The assembly of fibulin-1C and fibulin-1D in multiple locations is dependent upon the presence of hemicentin, a recently described extracellular member of the immunoglobulin superfamily. We suggest that the distinct developmental roles and hemicentin-dependent assembly for fibulin-1 splice variants demonstrated here may be relevant to fibulin-1 and possibly other fibulin family members in non-nematode species.
An application of Six Sigma methodology to reduce the engine-overheating problem in an automotive company
Authors: Antony J , Kumar M , Tiwari M K
Published: August 2005

Six Sigma is a systematic methodology for continuous process quality improvement and for achieving operational excellence. The overstatement that often accompanies the presentation and adoption of Six Sigma in industry can lead to unrealistic expectations as to what Six Sigma is truly capable of achieving. This paper deals with the application of Six Sigma based methodology in eliminating an engine-overheating problem in an automotive company. The DMAIC (define-measure-analyse-improve-control) approach has been followed here to solve an underlying problem of reducing process variation and the associated high defect rate. This paper explores how a foundry can use a systematic and disciplined approach to move towards the goal of Six Sigma quality level. The application of the Six Sigma methodology resulted in a reduction in the jamming problem encountered in the cylinder head and increased the process capability from 0.49 to 1.28. The application of DMAIC has had a significant financial impact (saving over $US110 000 per annum.) on the bottom-line of the company.
On the effectiveness of numerical simulation in the prediction of profile distortion in extrusion
Authors: Filice L , Gagliardi F , Micari F
Published: August 2005

Among the so-called ‘traditional processes’, extrusion represents one of the most diffused and utilized, since it permits the production of many industrial parts and raw materials. Of course, relevant knowledge on process mechanics and practice is nowadays available in the technical literature and in properly constructed handbooks. On the other hand, the introduction of finite element simulation, as a powerful analysis and design tool, opened new perspectives. Nowadays many researchers are involved in research tasks aimed at explaining some peculiar extrusion aspects.

In this paper the effectiveness of numerical simulation for a complex three-dimensional extrusion process analysis is investigated; in particular, the case of a lack of alignment between the billet/ram axis and the die axis is taken into account in order to verify the effectiveness of numerical predictions as it affects extrusion load and profile distortion. With this aim a proper experimental equipment was developed in order to impose a known misalignment to the die.
Classical wave localization and spectral gap materials
Authors: Sheng Ping , Chan Che Ting
Published: August 2005

In the study of classical waves, i.e., electromagnetic and elastic waves, wave localization and spectral gap materials are two of the most important developments over the past two decades. While the main subject matter of this volume is on spectral gap materials, it is the purpose of this article to attempt a qualitative overview of the two subjects, in terms of the underlying physics.
Acoustic band gap measurements in waveguides with periodic resonant structures
Authors: Ash John , Robertson William M.
Published: August 2005

Experimental measurements, using an impulse response technique, are reported on a one-dimensional acoustic band gap system composed of a waveguide with a series of regularly spaced resonant structures. The amplitude data of the experimental results demonstrate the frequency and extent of the forbidden transmission bands and the phase information is analysed to determine the acoustic dispersion — the band structure — in the one-dimensional array. The results exhibit generally good agreement with previous theoretical analysis both in terms of the location of the forbidden transmission frequencies and in the form of the band structure. This simple system is a good candidate for the exploration of a number of postulated acoustic band gap effects.
Experimental observation of resonant filtering in a two-dimensional phononic crystal waveguide
Authors: Vasseur Jerôme O. , Deymier Pierre A. , Beaugeois Maxime , Pennec Yan , Djafari-Rouhani Bahram , Prevost Dominique
Published: August 2005

Transmission of acoustic waves through a two-dimensional composite material made of PVC cylinders surrounded by air is measured experimentally. The spectrum presents a very large absolute band gap in the audible frequency range. A waveguide created inside this phononic crystal by removing a row of cylinders can transmit very efficiently the waves falling inside the stop band. We show the existence of deaf modes in the band structure of the linear waveguide. Resonant filtering is also demonstrated experimentally by coupling the waveguide to a side branch resonator of variable length. Frequency filtering is observed in the form of narrow dips in the transmission spectrum of the waveguide. Most of these observations compare favorably with theoretical calculations of dispersion curves and transmission coefficients of model structures using the plane wave expansion and the finite difference time domain methods. Narrow dips similar to those of the guide with resonator are also observed in the transmission spectrum of a waveguide with a sharp bend.
Tunneling and dispersion in 3D phononic crystals
Authors: Page John H. , Yang Suxia , Liu Zhengyou , Cowan Michael L. , Chan Che Ting , Sheng Ping
Published: August 2005

Tunneling and dispersion of ultrasonic pulses is investigated in 3D phononic crystals consisting of 0.8 mm-diameter tungsten carbide beads that are close packed in a fcc crystal array embedded in either water or epoxy. Pulsed ultrasonic techniques allow us to measure the phase velocity and group velocity, i.e. the dynamics of wave propagation, as well as the transmission coefficient. Our experimental data are well interpreted using multiple scattering theory (MST). In the tungsten carbide/water crystals, dispersion phenomena were studied at frequencies in and around the gap in the ΓL direction. A strong suppression of the group velocity, and large variations of the group velocity dispersion (GVD) were found at frequencies around the band edges. By contrast, fast group velocities and nearly constant GVD with values around zero were observed at gap frequencies, indicating that tunneling in phononic crystals is essentially dispersionless. In the tungsten carbide/epoxy crystals a wide gap (to our knowledge, largest measured 3D band gap) was measured covering a frequency range from 1.2 MHz to 4.3 MHz along the ΓL crystal direction. The agreement between the theory and experiments gives strong evidence of the existence of a large complete gap (1.5 MHz to 3.9 MHz), which is theoretically predicted from the band structure calculations.
Transmission properties of locally resonant sonic materials with finite slab thickness
Authors: Fung Kin Hung , Liu Zhengyou , Chan Che Ting
Published: August 2005

Using multiple-scattering theory, we studied the transmission properties of a slab of composite material that have sonic band gaps due to local resonances. Thin slabs of such material have transmission properties that are apparently different from conventional band gap material. For example, there can be transmission peaks in the frequency range inside the bulk sonic band gap. If the slab thickness is changed, we found that the top of band gap shifts while the bottom of band gap, being pinned by the resonance frequency, does not. By changing the slab thickness, the “effective band gap” may be narrowed or broadened, depending on the filling fraction of the locally resonant units. In order to provide an intuitive understanding of the phenomena, we constructed a simple model to understand the phenomena by comparing its transmission and band structure with that of the locally resonant sonic materials.
Inverse design of phononic crystals by topology optimization
Authors: Halkjaer Søren , Sigmund Ole , Jensen Jakob S.
Published: August 2005

Band gaps, i.e frequency ranges for which waves cannot propagate, can be found in most elastic structures if the material or structure has a specific periodic modulation of material properties. In this paper, we maximize phononic band gaps for infinite periodic beams modelled by Timoshenko beam theory, for infinite periodic, thick and moderately thick plates, and for finite thick plates. Parallels are drawn between the different optimized crystals and structures and several new designs obtained using the topology optimization method.
Elastic waves in arrays of elliptic inclusions
Authors: Guenneau Sebastien , Movchan Alexander B.
Published: August 2005

We consider in-plane elastic waves propagating through a doubly periodic array of cylinders of Tantalum (with both circular and elliptical cross-sections) which are embedded in a matrix of fused silica. We find some sonic gap for fairly small filling fractions of the cylinders which eventually vanish in the limit of high-filling fraction. In the case of a doubly periodic array of elliptical cylinders, removal of a cylinder within a macro-cell leads to two localised eigenstates.
APPRENTICE ETHNOGRAPHERS AND THE ANTHROPOLOGY OF TOURISM IN COSTA RICA
Authors: Wallace Tim
Published: August 2005

This chapter discusses the structure of North Carolina State University ethnographic field school program held in Costa Rica from 1995–2001 (and now in Guatemala since 2002), in addition to explaining how the program is run and its focus on the anthropology of tourism. It is argued that not all field schools are ethnographic but that ethnographic field schools are essential for apprentice anthropologists who want to understand what anthropology is all about. It explains what makes the NCSU program an ethnographic field school and why it seems to be a successful model. Former program participants also discuss how they have benefited from their experiences.
FULFILLING COMMUNITY NEEDS THROUGH RESEARCH AND SERVICE: THE NORTHWESTERN UNIVERSITY ETHNOGRAPHIC FIELD SCHOOL EXPERIENCE
Authors: Iris Madelyn
Published: August 2005

The Northwestern University Ethnographic Field School (EFS) was started in the early 1970s in order to offer undergraduate and early graduate students an opportunity to explore their affinity for fieldwork and gain firsthand experience with the conduct of original research. Operating on the Navajo Nation in the southwestern United States, this eight‐week program combines rigorous training in ethnographic methods with a cultural immersion experience requiring volunteer service in a Navajo nonprofit or governmental agency or organization. Students may choose from a wide variety of volunteer placements, including work with children, women at risk, seniors, Navajo cultural institutions, or community service agencies dealing with issues such as AIDS, infant and child nutrition, and residential programs for children and adults with disabilities. EFS emphasizes cross‐cultural understanding through direct service, immersion in the host community, and improvement of students' skills in ethnographic methods. Included in the curriculum is exposure to the ethical conduct of research, the practice of participatory action research, and collaboration with Navajo mentors, as well as teachings on Navajo history and culture, and an introduction to the Navajo language.
LEARNING TO PUT ETHNOGRAPHY TO GOOD USE: THE GAMBIA, WEST AFRICA FIELD STUDY PROGRAM
Authors: Roberts Bill
Published: August 2005

The St. Mary's College of Maryland Gambia Field Study Program began in 1996 when ten students with a variety of majors, led by Professor Bill Roberts, learned to apply ethnographic research techniques to their service‐learning or research projects. A total of four programs have been completed to date, the most recent being the subject of the documentary film, Tubabs in Africa (2002). The course is designed to assist students from any major learn basic language and culture skills to live comfortably in The Gambia for seven weeks and carry out an individual, firsthand research project using ethnographic and other appropriate techniques. All students spend the first two weeks together studying the Mandinka language and learning about Gambian culture. Gambian and expatriate guest speakers and field trips around the Greater Banjul Area provide students with the basic grounding they need for success. The group then travels to various sites “upcountry” for about a week to learn more about country ecology and rural life in Gambia. Another trip to the Senegalese capital city of Dakar provides students with further contrasts between countries with different colonial histories, and an opportunity to visit the World Heritage Site of Goree Island. The final half of the course students are directed on individual research projects they devise with the assistance of the instructor on topics that range from primate studies to fisheries to public health. The course challenges students to be flexible and adaptable, to work in team settings and as individual researchers, and to develop skills for acquiring intercultural competency in Gambia. The next field school for the summer of 2004 will also feature an archaeological component.
ETHNOGRAPHIC FIELD SCHOOLS, COMMUNITY SERVICE LEARNING, AND THE HOMESTAY EXPERIENCE
Authors: Diamente Daniela Natale
Published: August 2005

Our experience in training undergraduate and graduate anthropology students during ten consecutive summers of ethnographic field schools in diverse settings (Hungary, Lowland Costa Rica, Highland Guatemala) leads us to believe that students, both graduate and undergraduate need a strong, basic experience in designing and conducting their own field research projects. At the same time, we believe that the ethnographic field school experience is also a type of service learning experience. The ethnographic field school helps students develop analytic and conceptual skills that can be linked with applied experiences. Eventually, both the participants and the members of the local community enter into a mutually reinforcing relationship in which the guests come to appreciate their role as students of the local culture, and as anthropologists (framed within a professional sense of ethical responsibility) and in which the hosts come to understand what research is and how that research can be put to use. Some programs emphasize a more active model of community service with frequent, direct, community involvement and collaboration, while others use a more passive model whose benefits for the local community come through the information generated from research projects and from the homestay experience. This chapter gives several examples of each kind of model.
CONCLUSION: HOW TO PICK A FIELD SCHOOL THAT'S RIGHT FOR YOU
Authors: Iris Madelyn
Published: August 2005

Choosing to participate in an ethnographic or cultural anthropology field school is an important decision. There are a number of questions to consider when making a choice. These include: Know what is expected of you—what are the outcomes? What is the methodological “thrust” of the program—will you be in sync? What is the length of time of commitment—can you meet it? What is the relationship between the host community and the field school? Are you okay with it? Is there a language requirement and if so, can you meet it? How much structure is provided and what are your needs? Do you like to work independently or in a group? Would you feel most comfortable alone or in a group setting? How much day‐to‐day structure or supervision will you need and will you be likely to receive? Does the field school operate in a setting in which you want to be? Country? Locale? Climate? Are there any safety concerns you should consider? Will your university or college accept transfer credits if these are offered? Do you care? How much mentorship is provided? How much do you want? Is there an orientation and what does it cover? Are there prerequisites and are you adequately prepared? This chapter discusses what to think about as you try to answer these questions. To make the best choice possible, you need to think about what you wish to gain from the experience, your preferences, strengths and weaknesses. To get the most out of a field school experience, you should look for a program that challenges you to reach beyond your comfort zone, but not one that places such demands on you that you can never succeed. Because we do not often know the limits of our capacities, the key essential element for any student is the ability to be flexible, creative, and curious. If you can draw on these three characteristics, you are sure to be successful.
ANTHROPOLOGICAL ANGST AND THE TOURIST ENCOUNTER
Authors: DOUGLASS WILLIAM A. , LACY JULIE
Published: August 2005

Informed by and critical of the anthropological critique of tourism, this work is a retrospective examination of one author's willingness to act as consultant to a financially motivated tourism‐development scheme in the Basque region of Spain. Navigating between the Scylla of cultural commodification and the Charybdis of local agency and voice, the anthropologist's role in such a project is fraught with anthropological angst. We consider two critical works on Basque tourism that warn against such involvement, but in the end conclude that the decision must be made on a case‐by‐case basis.
AN ANTHRO‐PLANNING APPROACH TO LOCAL HERITAGE TOURISM: CASE STUDIES FROM APPALACHIA
Authors: LALONE MARY B.
Published: August 2005

This article argues for the use of an anthro‐planning approach in local‐level development projects, focusing here on its use in heritage tourism development. Anthro‐planning is an approach that infuses anthropological perspectives and methods into planning projects. The article starts by discussing some guiding principles for an anthro‐planning approach derived from the author's experiences in planning regional heritage tourism–education sites. The emphases are (1) taking a collaborative or partnership approach that actively seeks public participation in the planning process and (2) extensively incorporating anthropological field methods into the project design. The article then provides some concrete examples by showing how this approach was applied in planning two cultural heritage parks for an Appalachian Virginia region. One case documents the planning of an Appalachian coal‐mining heritage park while the other example focuses on development of an Appalachian farm heritage museum and park.
MORE THAN NATURE: ANTHROPOLOGISTS AS INTERPRETERS OF CULTURE FOR NATURE‐BASED TOURS
Authors: INGLES PALMA
Published: August 2005

Anthropologists have much to offer as interpreters of cultures for tourists traveling to remote areas of the world. Often advertised as ecotours, group travel is now being offered to areas of the world that are still considered off the beaten path. With more and more travel taking place in the form of organized, guided tours, the anthropologist is in a prime position to educate travel companies and tourists concerning the populations with which they come into contact while enhancing the experience for both the tourists and the host populations. Colorful brochures advertise tours that will have a range of naturalists to guide the tourists through the natural environment in a chosen destination. Rarely do tours advertise that they have anthropologists to help tourists learn more about the local cultures. This paper explores the benefits of hiring anthropologists as tour guides for nature‐based tours, using examples from the Amazon.