bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinematic Calibration and Pose Measurement of a Medical Parallel Manipulator by Optical Position Sensors
Authors: Bai Shaoping , Teo Ming Yeong 
Published: March 2003

AbstractIn the applications of parallel manipulators, kinematic calibration is required to eliminate the errors resulting from the manufacturing and assembly of both base and tools. In this paper, a calibration method of base and tool transformation is developed by virtue of optical position sensors. An error model for calibration is constructed using differential geometry method. The pose error is obtained based on pose measurement results of OPTOTRAK 3020, a commercial 3D position measurement system. An iterative least squares procedure is used to identify the error parameters in the base and tool transformations. Simulation and experiment results are presented to demonstrate the effectiveness of the method for transformation matrices calibration. © 2003 Wiley Periodicals, Inc.
Integer and fractional packings in dense 3‐uniform hypergraphs
Authors: Haxell Penny , Nagle Brendan , Rödl Vojtěch 
Published: March 2003

AbstractLet 𝒥0be any fixed 3‐uniform hypergraph. For a 3‐uniform hypergraph ℋ︁ we define ν(ℋ︁) to be the maximum size of a set of pairwise triple‐disjoint copies of 𝒥0in ℋ︁. We say a function ψ from the set of copies of 𝒥0in ℋ︁ to [0, 1] is afractional𝒥0‐packingof ℋ︁ if ∑𝒥∋eψ(𝒥) ≤ 1 for every tripleeof ℋ︁. Then ν(ℋ︁) is defined to be the maximum value of ∑ψ(𝒥) over all fractional 𝒥0‐packings ψ of ℋ︁. We show that ν(ℋ︁) − ν(ℋ︁) =o(|V(ℋ︁)|3) for all 3‐uniform hypergraphs ℋ︁. This extends the analogous result for graphs, proved by Haxell and Rödl (2001), and requires a significant amount of new theory about regularity of 3‐uniform hypergraphs. In particular, we prove a result that we call the Extension Theorem. This states that if ak‐partite 3‐uniform hypergraph is regular [in the sense of the hypergraph regularity lemma of Frankl and Rödl (2002)], then almost every triple is in about the same number of copies ofK(the complete 3‐uniform hypergraph withkvertices). © 2003 Wiley Periodicals, Inc. Random Struct. Alg., 22: 248–310, 2003
The number of k‐SAT functions
Authors: Bollobás Béla , Brightwell Graham R. 
Published: March 2003

AbstractWe study the number SAT(k; n) of Boolean functions of n variables that can be expressed by a k‐SAT formula. Equivalently, we study the number of subsets of the n‐cube 2n that can be represented as the union of (n − k)‐subcubes. In The number of 2‐SAT functions (Isr J Math, 133 (2003), 45–60) the authors and Imre Leader studied SAT(k; n) for k ≤ n/2, with emphasis on the case k = 2. Here, we prove bounds on SAT(k; n) for k ≥ n/2; we see a variety of different types of behavior. © 2003 Wiley Periodicals, Inc. Random Struct. Alg., 22: 227–247, 2003
Understandings of the nature of science and decision making on science and technology based issues
Authors: Bell Randy L. , Lederman Norman G. 
Published: March 2003

AbstractThe purpose of this investigation was to explicate the role of the nature of science in decision making on science and technology based issues and to delineate factors and reasoning associated with these types of decisions. Twenty‐one volunteer participants purposively selected from the faculty of geographically diverse universities completed an open‐ended questionnaire and follow‐up interview designed to assess their decision making on science and technology based issues. Participants were subsequently placed in one of two groups based upon their divergent views of the nature of science as assessed by a second open‐ended questionnaire and follow‐up interview. Profiles of each group's decision making were then constructed, based on participants' previous responses to the decision making questionnaire and follow‐up interviews. Finally, the two groups' decisions, decision influencing factors, and decision making strategies were compared. No differences were found between the decisions of the two groups, despite their disparate views of the nature of science. Participants in both groups based their decisions primarily on personal values, morals/ethics, and social concerns. While all participants considered scientific evidence in their decision making, most did not require absolute “proof,” even though many participants held absolute conceptions of the nature of science. Overall, the nature of science did not figure prominently in either group's decisions. These findings contrast with basic assumptions of current science education reform efforts and call for a re‐examination of the goals of nature of science instruction. Developing better decision making skills—even on science and technology based issues—may involve other factors, including more value‐based instruction and attention to intellectual/moral development. © 2003 Wiley Periodicals, Inc. Sci Ed 87:352–377, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/sce.10063
Innovative science within and against a culture of “achievement”
Authors: Carlone Heidi B. 
Published: March 2003

AbstractAs science educators struggle to reform science education, we need a better understanding of the conundrums associated with the ways educators enact innovative science within and against the “academic,” “rigorous,” and “elite” sociohistorical constructions of science. I ethnographically investigated the meanings of an innovative, reform‐based curriculum (Active Physics) in various micro (classroom) and macro (school and community) contexts. I conducted the study in a high school serving primarily upper middle class students, the majority of whom (97%) planned to attend college. I explored how meanings of the curriculum transformed as the curriculum traveled across space and time. While certain aspects of the context enabled innovative science (e.g., support from the administration, pressure to serve a wider range of students), other aspects of the context constrained the potential of the curriculum (e.g., the need to establish for students, parents, and administrators the legitimacy of Active Physics as “real” and “rigorous” physics). Using practice theory to understand the influence of context and agency in shaping school science practice, this study demonstrates the potential for viewing meanings of science in local settings as partially fluid entities, sometimes reproducing and sometimes contesting sociohistorical legacies. © 2003 Wiley Periodicals, Inc.Sci Ed87:307–328, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/sce.10071
Evolution of KL satellite of F in CaF2
Authors: Uda M. , Yamamoto T. , Ogyu Y. , Yamashita D. , Perera R. C. C. , Mukoyama T. 
Published: March 2003

AbstractPhotoexcited F Kα satellite spectra of CaF2 were studied as a function of excitation energy from threshold. The observed spectra show that the intensity evolution of the KL satellite line is not a monotonic function increasing with excitation energy, in contrast to the prediction from the conventional shake model, but has a small bump. Comparison with the Hartree–Fock calculations indicates that the origin of the bump can be ascribed to resonances of multi‐electron excitation processes in photoabsorption. Copyright © 2003 John Wiley & Sons, Ltd.
Calculation of attenuation and x‐ray fluorescence intensities for non‐parallel x‐ray beams
Authors: Malzer Wolfgang , Kanngießer Birgit 
Published: March 2003

AbstractWith the nowadays widespreaded use of x‐ray optics in x‐ray fluorescence analysis, large convergence or divergence angles can occur. This experimental situation violates a basic assumption of the usual fundamental parameter quantification procedure. In order to take beam divergences in micro x‐ray fluorescence analysis into account, a way of calculating fluorescence intensities numerically by Monte Carlo integration is described. For three examples of typical micro‐XRF set‐ups the fluorescence intensities and their deviation from the parallel beam geometry are calculated. Furthermore, we propose a new approach with ‘equivalent angles’ which correct for the beam divergences in fundamental parameter methods. Copyright © 2003 John Wiley & Sons, Ltd.
FACTORS AFFECTING THE ADOPTION OF LEGUMINOUS COVER CROPS IN NIGERIA AND A COMPARISON WITH THE ADOPTION OF NEW CROP VARIETIES
Authors: MORSE S. , McNAMARA N. 
Published: March 2003

This paper presents the results of:(a) On-farm trials (eight) over a two-year period designed to test the effectiveness of leguminous cover crops in terms of increasing maize yields in Igalaland, Nigeria.(b) A survey designed to monitor the extent of, and reasons behind, adoption of the leguminous cover crop technology in subsequent years by farmers involved, to varying degrees, in the trial programme.Particular emphasis was placed on comparing adoption of leguminous cover crops with that of new crop varieties released by a non-governmental organization in the same area since the mid 1980s. While the leguminous cover crop technology boosted maize grain yields by 127 to 136% above an untreated control yield of between 141 and 171 kg ha−1, the adoption rate (number of farmers adopting) was only 18%. By way of contrast, new crop varieties had a highly variable benefit in terms of yield advantage over local varieties, with the best average increase of around 20%. Adoption rates for new crop varieties, assessed as both the number of farmers growing the varieties and the number of plots planted to the varieties, were 40% on average. The paper discusses some key factors influencing adoption of the leguminous cover crop technology, including seed availability. Implications of these results for a local non-governmental organization, the Diocesan Development Services, concerned with promoting the leguminous cover crop technology are also discussed.
EVALUATION OF INTEGRATED STRIGA HERMONTHICA CONTROL TECHNOLOGIES UNDER FARMER MANAGEMENT
Authors: SCHULZ S. , HUSSAINI M. A. , KLING J. G. , BERNER D. K. , IKIE F. O. 
Published: March 2003

On-farm trials were conducted in the northern Guinea savanna of Nigeria. The objective was to compare integrated Striga hermonthica control measures (soyabean or cowpea trap crop in the first year followed by maize resistant to Striga in the second year) with farmers' traditional practices (cereal-based cropping systems) under farmer-managed conditions.Integrated control proved to be highly effective in terms of reducing Striga incidence both in terms of reduced seed density in the soil and decreased infection in maize. Resistant maize following the soyabean trap crop yielded 1.58 t ha−1 of grain and out-yielded local maize following traditional practices by more than 80%. Similarly, the overall productivity over the period of the experiment was highest with the integrated control treatment using soyabean. Conversely, resistant maize after the cowpea trap crop yielded only 0.92 t ha−1 (possibly due to the poor performance of the cowpea crop in the first year), and maize yields were similar to those obtained with farmer practices. Initial Striga seed density in the soil was negatively correlated (r = −0.33) with soil nitrogen, but nitrogen-fertilizer application rates did not seem to affect the level of Striga infection in maize.
Flow along streamwise corners revisited
Authors: RIDHA A. 
Published: March 2003

In this paper we investigate the three-dimensional laminar incompressible steady flow
along a corner formed by joining two similar quarter-infinite unswept wedges along
a side-edge. We show that a four-region construction of the potential flow arises
naturally for this flow problem, the formulation being generally valid for a corner of
an arbitrary angle (π−2α), including the limiting cases of semi- and quarter-infinite
flat-plate configurations. This construction leads to five distinct three-dimensional
boundary-layer regions, whereby both the spanwise length and velocity scales of the
blending intermediate layers are O(δ), with Re−1/2 [Lt ] δ [Lt ] 1, Re being a reference
Reynolds number supposed to be large. This reveals crucial differences between
concave and convex corner flows. For the latter flow regime, the corner-layer motion
is shown to be mainly controlled by the secondary flow which effectively reduces to
that past sharp wedges with solutions being unique and existing only for favourable
streamwise pressure gradients. In this regime, the corner-layer thickness is shown
to be O(Re−0.5+α/π/δ2α/π), −½π [les ] α [les ] 0, which is much smaller than O(Re−1/2) for
concave corner flows.Crucially, our numerical results show conclusively that, for α ≠ 0, closed streamwise
symmetrically disposed vortices are generated inside the intermediate layers, confirming
thus the prediction made by Moore (1956) for a rectangular corner, which has so
far remained unconfirmed in the literature.For almost planar corners, three-dimensional corner boundary-layer features are
shown, as in (Smith 1975), to arise when α ∼ O(1/ln Re). On the other hand, we
show that the flow past a quarter-infinite flat plate would be attained when both
values of the streamwise pressure gradient and external corner angle (π+2α) become
O(1/ln Re) or smaller.Numerical results for all these flow regimes are presented and discussed.
Elliptic and triangular instabilities in
rotating cylinders
Authors: ELOY CHRISTOPHE , LE GAL PATRICE , LE DIZÈS STÉPHANE 
Published: March 2003

In this article, the multipolar vortex instability of the flow in a finite cylinder is
addressed. The experimental study uses a rotating elastic deformable tube filled
with water which is elliptically or triangularly deformed by two or three rollers.
The experimental control parameters are the cylinder aspect ratio and the Reynolds
number based on the angular frequency.For Reynolds numbers close to threshold, different instability modes are visualized
using anisotropic particles, according to the value of the aspect ratio. These modes
are compared with those predicted by an asymptotic stability theory in the limit
of small deformations and large Reynolds numbers. A very good agreement is
obtained which confirms the instability mechanism; for both elliptic and triangular
configurations, the instability is due to the resonance of two normal modes (Kelvin
modes) of the underlying rotating flow with the deformation field. At least four
different elliptic instability modes, including combinations of Kelvin modes with
azimuthal wavenumbers m = 0 and m = 2 and Kelvin modes m = 1 and m = 3 are
visualized. Two different triangular instability modes which are a combination of
Kelvin modes m = −1 and m = 2 and a combination of Kelvin modes m = 0 and
m = 3 are also evidenced.The nonlinear dynamics of a particular elliptic instability mode, which corresponds
to the combination of two stationary Kelvin modes m = −1 and m = 1, is examined
in more detail using particle image velocimetry (PIV). The dynamics of the phase and
amplitude of the instability mode is shown to be predicted well by the weakly nonlinear
analysis for moderate Reynolds numbers. For larger Reynolds number, a secondary
instability is observed. Below a Reynolds number threshold, the amplitude of this
instability mode saturates and its frequency is shown to agree with the predictions
of Kerswell (1999). Above this threshold, a more complex dynamic develops which is
only sustained during a finite time. Eventually, the two-dimensional stationary elliptic
flow is reestablished and the destabilization process starts again.
The Linguasphere: kaleidoscope of the world's languages
Authors: Dalby David 
Published: March 2003

A description of ‘the mantle of communication ... extended
around the planet’The new perceptions afforded by the era of telecommunications may be compared to those of
the Renaissance or the Enlightenment. That the world is a globe, or that blood circulates around
the body, became obvious only a few centuries ago...as it now becomes apparent that all spoken
and written languages form an organic continuum, a global medium for human communication and
the circulation of ideas.The continuity of communication between communities in contact
has always been maintained by those who speak more than one language, by those whose brains
have attempted to bridge the differences of viewpoint and expression embodied in the use of
differing languages by different communities. It is only in modern times, however,
that networks of bilingual links among thousands of speech communities around the
world can be seen in global perspective. The ancient continuum of multilingual speech is
becoming a system of immediate worldwide communication.
Private tuition in English: the case of two universities in Jordan
Authors: Khuwaileh Abdullah A. , Al-Shoumali Ali 
Published: March 2003

An account from Jordan of an ‘elitist’ phenomenon that is spreading
elsewhere in Asia.This study explores the reasons and conditions which have recently led a
substantial number of families to hire private tutors of English for their sons and/or
daughters studying science and technology through English in Jordanian state universities.
The polemics of Singlish
Authors: Mei Lee-Wong Song 
Published: March 2003

An examination of the culture, identity and function of English in Singapore.The widespread use of English in Singapore has placed Singapore in the Outer Circle, along with India, Pakistan, Sri Lanka, Ghana, Nigeria, the Philippines and others, in contrast with Australia, the United Kingdom, the United States and others who belong to the Inner Circle (Kachru,1991). Placing countries in different circles – inner vs outer or expanding, based on the concept of nativization – has generated questions of democracy in linguistic ideology and related issues of norms and standards. These are discussed.
When is English not the right choice in Sarawak?
Authors: Ting Su-Hie 
Published: March 2003

A discussion of language choices in a multilingual region of Malaysia.Sarawak is a Malaysian state located on the island of Borneo.
More than 20 languages are spoken there among only 1.99 million people in Sarawak. People who
visit Sarawak for the first time are often baffled and intrigued by the diversity of languages
and the ease with which Sarawakians switch between them. To add to the complexity of language
choice, there is also some competition between English and Standard Malay for dominance in language
use.This paper considers the reasons for the complex language scenario in Sarawak, the social
implications of language choices, and the important personal characteristics to consider in making
language choices.
Calling for a truce in the descriptivist-prescriptivist wars
Authors: Garner Bryan A. 
Published: March 2003

A reply to Tom McArthur, ‘Error, Editing, and
World Standard English’, ET65 (Jan 01)When modern linguists focus exclusively on speech, they're overreacting to their
predecessors' preoccupation with writing. Descriptivists have a bias toward
studying speech; prescriptivists have a bias toward studying writing. Both are
important. Speaking precedes writing. It's the essence of language.
Yet writing is a form of language worth studying in its own right. For some reason,
though, many linguists refuse to recognize this.
Comparative foraging ecology of five sympatric terns at a sub‐tropical island in the eastern Indian Ocean
Authors: Surman C. A. , Wooller R. D. 
Published: March 2003

AbstractOver one million pairs of seabirds breed annually on the Houtman Abrolhos island group, off the mid‐western coast of Australia, the largest seabird breeding station in the eastern Indian Ocean. Eight of the 13 species that breed annually on Pelsaert Island are terns. Dietary samples (regurgitates) were collected from the five most numerous tern species from 1993 to 1999. The prey items identified were related to observations of foraging seabirds around the island. The largest species studied, the crested tern Sterna bergii, foraged mainly for reef fish over shallow reef flats near the breeding islands, as well as for schooling clupeid fish over coastal shelf waters. The smallest species, the roseate tern S. dougallii, also foraged within sight of its colonies, but over deeper waters than crested terns. Three larval fish species characteristic of continental shelf waters (a gonorhynchid, a goatfish and a bellowfish) figured prominently in the diets of roseate terns and three other tern species studied. Of these, only the sooty tern S. fuscata also ate squid and lanternfishes, foraging farthest (480–600 km) from its breeding island, off the shelf edge. The lesser noddy Anous tenuirostris and brown noddy A. stolidus took very similar taxa of prey and also overlapped considerably in their foraging ranges, about 180 km from their colonies, between the islands and the continental shelf edge. However, the lesser noddy took smaller fish than did the larger brown noddy. Although these five abundant tropical tern species, that bred sympatrically, showed some segregation in their diets and, more clearly, in their foraging ranges, considerable overlap of both aspects remained.
Segregation of migration by feeding ground origin in North Atlantic humpback whales (Megaptera novaeangliae)
Authors: Stevick Peter T. , Allen Judith , Bérubé Martine , Clapham Phillip J. , Katona Steven K. , Larsen Finn , Lien Jon , Mattila David K. , Palsbøll Per J. , Robbins Jooke , Sigurjónsson Jóhann , Smith Tim D. , Øien Nils , Hammond Philip S. 
Published: March 2003

AbstractResults from a large‐scale, capture—recapture study of humpback whales Megaptera novaeangliae in the North Atlantic show that migration timing is influenced by feeding ground origin. No significant differences were observed in the number of individuals from any feeding area that were re‐sighted in the common breeding area in the West Indies. However, there was a relationship between the proportion (logit transformed) of West Indies sightings and longitude (r2=0.97, F1,3=98.27, P=0.0022) suggesting that individuals feeding farther to the east are less likely to winter in the West Indies. A relationship was also detected between sighting date in the West Indies and feeding area. Mean sighting dates in the West Indies for individuals identified in the Gulf of Maine and eastern Canada were significantly earlier than those for animals identified in Greenland, Iceland and Norway (9.97 days, t179=3.53, P=0.00054). There was also evidence for sexual segregation in migration; males were seen earlier on the breeding ground than were females (6.63 days, t105=1.98, P=0.050). This pattern was consistently observed for animals from all feeding areas; a combined model showed a significant effect for both sex (F1=5.942, P=0.017) and feeding area (F3=4.756, P=0.0038). The temporal difference in occupancy of the West Indies between individuals from different feeding areas, coupled with sexual differences in migratory patterns, presents the possibility that there are reduced mating opportunities between individuals from different high latitude areas.
Rates of population increase in the ricefield rat (Rattus argentiventer) as a function of food supply: an enclosure study in Jatisari, West Java
Authors: Tristiani Harsiwi , Murakami Okimasa 
Published: March 2003

AbstractThe relationship between the population dynamics of ricefield rats Rattus argentiventer and their food supply, rice plants, was investigated in an enclosure in Jatisari, West Java. The density of the rat population fluctuated greatly throughout the year depending on the growth stages of the rice plants. A model illustrating the responses of the rat population to the growth stages of the rice plants is described. The population increased following periods when high‐quality rice plants were available, and decreased following periods when only low‐quality rice plants were available. The highest rate of increase (r) over a 2‐week period was observed during the dry season of 1989 (r=1.77). The lowest rate of increase over 2 weeks was observed during the rainy season of 1989–90 (r=−0.59). The maximum rate of increase for the ricefield rat in the numerical response function was 1.183 month−1, and the best estimate for the numerical response function was robs=−3.890±5.043(1−e−0.026V).