bluuebunny/crossref_metadata_2025 huggingface dataset:
Oelandiella, the earliest Cambrian helcionelloid mollusc from Siberia
Authors: Gubanov Alexander P. , Peel John S.
Published: November 2003

The helcionelloid molluscs Oelandiella korobkoviO. sibirica Vostokova are redescribed on the basis of type material from the lowest Cambrian of northern Siberia. Oelandiella is reinstated as a recognizable genus separated from Latouchella Cobbold, of which it has been considered generally to be a junior synonym, by differences in the prominent comarginal plication. The bilaterally symmetrical shells of both of these genera are readily delimited from Oelandia Westergård, originally described from the Middle Cambrian of Sweden, which has a characteristic asymmetrical alternation of plicae.
A new Carboniferous rugose coral genus from northern England
Authors: Nudds JOHN R.
Published: November 2003

Pleionastraea gen. nov. of the family Lithostrotionidae is described from the Lower Carboniferous Brigantian Stage of northern England. Two species, P. magnaP. matura, are referred to it. This astraeoid/thamnasterioid genus is distinguished from Orionastraea by its larger dimensions, but is considered to have followed the same evolutionary trend of a gradual breakdown of the corallite wall.
A new sigillid ostracod from submarine caves of the Ryukyu Islands, Japan
Authors: Tabuki Ryoichi , Hanai Tetsuro
Published: November 2003

A new troglobitic sigillid genus, Kasella, is found in the submarine caves of the Ryukyu Islands. Sigillids are primitive podocopid ostracods having ancient characters such as unequal valves and many small adductor muscle scars. Kasella is possibly derived from the sigillid Cardobairdia, a deep‐sea muddy bottom inhabitant, or its relatives. Submarine caves are characterized as both ‘safe places’, where biological factors such as competition and predation are reduced, and as ‘crypts’, representing dark and oligotrophic environments. It is likely that Kasella has successfully colonized hard substrates in caves, particularly exploiting the crevices on cave walls and ceilings. Kasella may have adapted to this cryptic habitat in response to strong cytheroidean competition and predation by, for example, gastropods that do not survive well in dark and oligotrophic submarine caves. In adapting to an oligotrophic cave environment, Kasella has undergone significant divergence in carapace morphology, possibly accompanying functional and behavioural changes.
The earliest atrypides and athyridides (Brachiopoda) from the Ordovician of Kazakhstan
Authors: Popov Leonid E. , Nikitin Igor F. , Sokiran Elena V.
Published: November 2003

The middle Ordovician brachiopod faunas of Kazakhstan provide one of the most complete records of the evolution and radiation of some of the oldest known spire‐bearing brachiopods. By contrast with North American faunas, Kazakhstanian atrypide taxa mostly belong to the suborders Atrypidina and Lissatrypidina, whereas the suborder Anazygidina is completely absent. Kazakhstanian species referred previously to ZygospiraKuzgunia are reassigned to Sulcatospira, which appeared in the Caradoc Diplograptus multidensClimacograptus clingani biozones (Sulcatospira? praecursor and Sulcatospira prima sp. nov.). Primitive, and possibly the oldest known Athyridida also appeared in Kazakhstan sometime during the Caradoc (Kellerella misiusi sp. nov.) and became widespread in brachiopod assemblages developed in carbonate mud mounds. Phylogenetic analysis suggests the early divergence of the Anazygidina, Atrypidina and Athyridida, which probably evolved independently from various primitive smooth Lissatrypidina. The new atrypide subfamily Pectenospirinae and two new atrypide genera (Rozmanospira gen. nov. and Pectenospira gen. nov. with P. pectenata sp. nov. as type species) are erected.
The nautiloid cephalopod order Ascocerida in the British Silurian
Authors: Hepworth Holland Charles
Published: November 2003

A brief review of the unusual morphology and ontogeny of the ascoceratid shell is followed by revised description of the meagre British Silurian material assigned already to Ascoceras barrandei Salter and A. vermiforme Blake.
Chemico‐structural evolution of linguloid brachiopod shells
Authors: Cusack Maggie , Williams Alwyn , Buckman James O.
Published: November 2003

Chemico‐structures of shells representing all families presently assigned to the Linguloidea have undergone significant transformations since the Early Cambrian. Superficial hemispherical to hemi‐ellipsoidal pits on the larval and/or mature shells are interpreted as casts of deformable, membrane‐bound vesicles of mucus or rigid vesicles of glycoproteins or GAGs with thickened coats. Flat‐bottomed, sub‐circular imprints characterize acrotheloids and many acrotretides, and could be impressions of biconvex tablets of apatite like those exocytosed within the primary layer of the obolid ‘Lingulella’? antiquissima, whilst the rhomboidal imprints of the Paterula shell could have held tablets of proteinaceous silica like those of living discinid larvae. The ancestral fabric of the linguloid secondary layer was probably composed of rubbly and virgose sets, but trellised rods of apatite (baculation) are characteristic of most linguloids and also acrotheloids. This condition was suppressed in shells identified as ‘Lingula’ from at least the Early Carboniferous to the present day. In early Palaeozoic acrotretides and lingulellotretids, columnar and camerate fabrics evolved in place of baculation. Baculation in Discinisca tenuis and Glottidia pyramidata is associated with the amino acids glutamic acid, glycine, alanine, arginine and proline which may be components of an organic polymer axial to baculate accretion.
Semblant Land Plants from the Middle Ordovician of the Prague Basin Reinterpreted as Animals
Authors: Kenrick Paul , Kvaček Zlatko , Bengtson Stefan
Published: November 2003

Two plant‐like fossil are described from the middle Ordovician of the Prague Basin, Czech Republic. Both fossils bear a strong superficial resemblance to early land plants, but anatomical data indicate an affinity with animals. New evidence on internal structure demonstrates that the putative plant Boiophyton pragense Obrhel is a dendroid graptolite. The relationships of other heavily coalified, branched axes found in associated strata are more obscure. Scanning electron microscopy of surface features suggests that these plant‐like remains are fossils of the collagenous stipes of gorgonacean octocorals.
Palaeoecological and phylogenetic implications of a new scleractiniamorph genus from Permian sponge reefs, south China
Authors: Ezaki Y.
Published: November 2003

Scleractinian corals are the most important constituents of modern coralgal reefs. For many years, it was thought that they first appeared in the Middle Triassic and subsequently underwent explosive radiation. However, abundant scleractinian‐like corals with ancestral morphological traits have recently been recovered from Middle Permian sponge reefs in China, which not only confirms a role in Permian reef ecology but also suggests a possible Palaeozoic origin for the group. Two species of a new Permian scleractiniamorph genus from China are described herein as Houchangocyathus wangi gen. et sp. nov. and Houchangocyathus yaoi gen. et sp. nov.  Putative Palaeozoic Scleractinia may have evolved over a substantial time interval and diverged into stem lineages by the end of the Permian. These forms evolved within both the rigid framework of their basic body plan and the morphological constraints characteristic of each lineage. The Middle Permian development of calcisponge reefs was closely related to habitat expansion, which would have provided an ideal dwelling for scleractinian‐like corals and enhanced their chances of fossilization. Such scleractiniamorphs disappeared at the end‐Permian extinction, but may have survived as progenitors of Triassic Scleractinia.
A new psittaciform bird from the London Clay (Lower Eocene) of England
Authors: Dyke Gareth J. , Cooper Joanne H.
Published: November 2003

A new psittaciform bird from the Lower Eocene (Ypresian) London Clay of England is described. This taxon, Pulchrapollia gracilis gen. et sp. nov., is assigned to the order Psittaciformes (parrots) on the basis of several distinctive structures of the tarsometatarsus, namely the trochlea for metatarsal III (trochlea metatarsi III) bearing a tubercle on its lateral side and the trochlea for metatarsal IV (trochlea metatarsi IV) completely retroverted (fully zygodactyl foot). Comparisons with other fossil and Recent taxa further support this conclusion. Cladistic analysis shows that Pulchrapollia is the sister‐taxon of the single extant family within Psittaciformes, the Psittacidae. Palaeopsittacus georgei, a taxon previously described from the London Clay, is most likely based on some unassociated material and is regarded here as incertae sedis.
Cranial anatomy and palaeobiology of the Miocene marsupial Hondalagus altiplanensis and a phylogeny of argyrolagids
Authors: SÁnchez‐Villagra Marcelo R. , Kay Richard F. , Anaya‐Daza Federico
Published: November 2003

New cranial material of Hondalagus altiplanensis, from the middle Miocene of southern Bolivia, allows a rediagnosis of the genus and an assessment of its palaeobiology and phylogenetic relationships with other argyrolagid marsupials. The new specimens demonstrate several derived (synapomorphic) cranial features shared by HondalagusArgyrolagus: a globular braincase, ventrally directed occipital condyles, a broad zygomatic arch, and a short, deep dentary with a flat and long coronoid notch. Hondalagus had powerful masticatory muscles and its cementum‐encased hypselodont cheek teeth suggests it had a very abrasive diet. The deep fossae on the lateral aspect of the skull of argyrolagids, interpreted by Simpson as large, laterally‐facing orbits, are actually sharply margined temporal fossae. Hondalagus has a very large carotid foramen medially situated within the suture of the basisphenoid and basioccipital. A phylogenetic analysis of five argyrolagid genera was conducted using 32 characters (16 cranial, 16 dental) and a didelphid and a caenolestid as outgroups. Hondalagus‐Argyrolagus‐Microtragulus form a monophyletic group with an undescribed gen. et sp. nov. (MACN‐Ch‐1305) from the lower Miocene (Colhuehuapian) of Argentina as its sister taxon. Proargyrolagus appears as sister group to the other taxa of argyrolagids.
Water in the Middle East peace process
Authors: Haddadin Munther J.
Published: November 2003

Water resources occupy an important role in the bilateral negotiations of the Middle East peace process. This paper mentions the conflicting water plans for the utilization of the Jordan basin by Arabs and Israelis, and describes the issues that are to be handled in the process of peacemaking. It defines the water issues between Israel and each of its neighbouring entities: Jordan, the Palestinians, Syria and Lebanon, and reviews what has been addressed in the peace negotiations thus far. A more detailed review is made of the negotiation tracks where progress was made, and a less detailed review is made of the negotiations that settled the water dispute between Jordan and Israel. The paper alludes to the claims of water wars in the region and provides evidence that water has not been a catalyst for war in the Middle East. It also proposes some topics for research that can be of interest to alleviate water shortage.
Management of transboundary water resources: lessons from international cooperation for conflict prevention
Authors: Uitto Juha I. , Duda Alfred M.
Published: November 2003

Tensions over freshwater resources may become more frequent as pressures on water resources grow due to increased demand and variability of rainfall. Conflicts may take place between or within countries or between competing sectoral users. This paper focuses on institutional approaches for enhancing cooperation between countries for sustainable development of transboundary freshwater bodies and contributing basins. It is assumed that instead of being zones of conflict, shared water resources can provide a basis for cooperation and benefit–sharing provided that threats to the international waters are recognized and collaborative structures are created. The paper draws upon experiences gained within the international waters focal area of the Global Environment Facility, the main funding mechanism for countries to support the environmental management of transboundary water resources. Lessons for promoting peaceful cooperation for environmental management, benefit–sharing and sustainable use of transboundary freshwater resources are highlighted through examples from Africa, Central Asia and Latin America. Experience shows the importance of processes that bring together all sectors and actors whose actions affect the transboundary waterbody at regional, national and local levels. The development of a science–based diagnostic analysis is essential to identify the threats to the transboundary ecosystem and to break down the issues into manageable parts with the aim of developing a strategic action programme. Ensuring political commitment that can result in institutional, policy and legal reforms in the countries concerned is the key to sustainable development of the transboundary resource.
The resistance of delayed xenograft rejection to α(1,3)‐galactosyltransferase gene inactivation and CD4 depletion in a mouse‐to‐rat model
Authors: HANSEN ALASTAIR B. , KIRKEBY SVEND , AASTED BENT , DAHL KIRSTEN , HANSEN AXEL KORNERUP , DIEPERINK HANS , SVENDSEN METTE , KEMP EJVIND , BUSCHARD KARSTEN , D'APICE ANTHONY J.F.
Published: November 2003

Critical to the prevention of xenograft loss is the prevention of delayed xenograft rejection (DXR), due to its resistance to conventional immunosuppression. The role of the carbohydrate galactose‐α1,3‐galactose (α1,3Gal) has been a matter of great debate and it has been proposed that the reaction between α1,3Gal epitopes on donor endothelial cells and recipient anti‐α1,3Gal antibodies (Abs) may damage the graft during DXR. Recipient anti‐α1,3Gal Abs are produced by CD4‐dependent B cells. To test the above‐mentioned hypothesis, hearts from α1,3Gal‐free mice (GT‐Ko mice), generated by α1,3‐galacto‐syltransferase gene disruption, were transplanted to anti‐α1,3Gal antibody‐free Lew/Mol rats. This model consists of an α1,3Gal/α1,3Gal‐antibody‐free environment, eliminating a possible influence of this specific system on DXR. A subgroup of recipients were furthermore CD4 depleted in order to inhibit CD4‐dependent B‐cell antibody production. Rejected hearts were evaluated by light‐ and immunofluorescence microscopy. Treatment effects on recipient T‐cell subsets and cytokine expression were analyzed by flow cytometry, while antibody production was measured by ELISA. All recipients developed DXR with no differences among the groups. DXR was related to thrombosis with IgG and IgM desposition in vessel walls, as well as macrophage and granulocyte accumulation in the myocardium. No complement C3, CD4 cells or NK cells were found. Flow cytometric analysis confirmed peripheral blood CD4 depletion and IFN‐γ suppression in CD4 Ab‐treated recipients. Finally, ELISA showed that specific anti‐α1,3Gal Ab production was absent. However, Ab(s) against an unidentified Galα 1 were found among recipients. In our model, DXR is resistant to α1,3‐galactosyltransferase gene inactivation and CD4 depletion. However, other Galα 1 epitopes and antibodies may play a role during DXR. Further studies are needed to elucidate the precise pathways leading to DXR.
Improved serodiagnosis of early Lyme borreliosis: Immunoblot with local Borrelia afzelii strain
Authors: JOVIČIĆ VILMA Lj. , GREGO EDITA M. , LAKO BRANISLAV L. , RISTOVIĆ BLAGOJE M. , LEPŠANOVIĆ ZORICA A. , STAJKOVIĆ NOVICA T.
Published: November 2003

To improve the serodiagnosis of Lyme borreliosis (LB) the performances of four tests were evaluated. An indirect immunofluorescent assay based on Borrelia burgdorferi s.s. , enzyme‐linked immunosorbent assay (ELISA) based on local isolates of Borrelia afzelii and B. burgdorferi s.s., and immunoblot (IB) of B. afzelii were prepared. The serum panels contained 214 serum samples: control group (n=120) and patients at different stages of LB (n=94). The specificity of IB was 96%, of in‐house ELISA 93%, and of IFA 89%. In early LB the sensitivity of IFA was 36%, ELISA 67%, and IB 93%. In late‐stage LB the sensitivity was: 72% for IFA, 80% for ELISA, and 94% for IB. Comparison of in‐house and Behring ELISA showed that the sensitivity of the serological assay could be increased when the test was based on local Borrelia strains. IgM and IgG antibodies from sera of patients with early and late LB most frequently demonstrated reactivity to OspC. The other significant proteins in early LB were: p39, p41 in IgM IB, and p83/100, p39, Osp17 in IgG IB; in late LB: p39, p41 in IgM IB, and p83/100, Osp17, p21 and p43 in IgG IB. Using IB based on local B. afzelii isolates improves the serodiagnosis of early LB in our geographical region.
Design of a Novel Globular Protein Fold with Atomic-Level Accuracy
Authors: Kuhlman Brian , Dantas Gautam , Ireton Gregory C. , Varani Gabriele , Stoddard Barry L. , Baker David
Published: November 2003

A major challenge of computational protein design is the creation of novel proteins with arbitrarily chosen three-dimensional structures. Here, we used a general computational strategy that iterates between sequence design and structure prediction to design a 93-residue α/β protein called Top7 with a novel sequence and topology. Top7 was found experimentally to be folded and extremely stable, and the x-ray crystal structure of Top7 is similar (root mean square deviation equals 1.2 angstroms) to the design model. The ability to design a new protein fold makes possible the exploration of the large regions of the protein universe not yet observed in nature.
A Full Account of Holey Material
Authors: Suib Steven L.
Published: November 2003

Handbook of Zeolite Science and Technology
. Scott M. Auerbach, Kathleen A. Carrado, and Prabir K. Dutta, Eds. Marcel Dekker, New York, 2003. 1191 pp. $235. ISBN 0-8247-4020-3.

The editors aim to provide novices and experts alike a comprehensive survey of fundamental principles as well as the current state of zeolite research.
Effects of measurement strategy and statistical analysis on dose-response relations between physical workload and low back pain
Authors: Jansen J P , Burdorf A
Published: November 2003

Background:In epidemiological studies on physical workloads and back complaints, among the important features in modelling dose-response relations are the measurement strategy of the exposure and the nature of the dose-response relation that is assumed.

Aim:To evaluate the effect of these two features on the strength of the dose-response relation between physical load and severe low back pain.

Methods:The study population consisted of 769 workers in nursing homes and homes for the elderly. Observations at the workplace were made of 212 subjects. These observations were analysed to determine exposure to physical load according to two measurement strategies: the individual approach and the group approach. The nature of the dose-response relation was evaluated with nested logistic regression models.

Results:The group approach resulted in higher odds ratios for the associations between physical load and low back pain than the individual approach. Spline logistic regression models appeared to describe the dose-response relation between physical load and low back pain best. The corresponding curve showed small changes in risk for small changes in exposure, whereas the categorical model only showed sudden large changes in risk at predefined exposure values.

Conclusion:The choice for a particular measurement strategy of physical load influences the strength of the associations between physical load and severe low back pain. Spline models allow changes in risk over the whole exposure range and are therefore a promising approach to identify quantitative dose-response patterns between physical load and low back pain.
Skin temperature recovery from cold provocation in workers exposed to vibration: a longitudinal study
Authors: Cherniack M , Brammer A , Meyer J , Morse T , Peterson D , Fu R
Published: November 2003

Background:Vibration white finger (VWF) is characterised by arterial hyperresponsiveness and vasoconstriction following cold provocation. Several years after of removal from exposure, most subjects show improved finger systolic blood pressure (FSBP) under conditions of cold challenge, but continue to report cold hands and finger blanching.

Aims:To assess the underlying reasons for the persistence of cold symptoms.

Methods:A total of 204 former users of pneumatic tools with cold related hand symptoms were evaluated and then re-evaluated a year later. Symptoms were evaluated using the Stockholm Workshop Scale. Finger systolic blood pressure per cent (FSBP%) was assessed by comparing digital blood pressure in a cold provoked and normalised state. Fingertip skin temperature was measured during cooling and occlusion and during rewarming and recovery.

Results:There were dramatic improvements in FSBP% (14.3 mm Hg %), modest improvement in recovered skin temperature (0.86°C), and no change in symptom stage. When the most symptomatic subjects (n = 75) were compared with the less symptomatic subjects (n = 129), there were similar inter-test improvements in FSBP%. Skin temperature recovery improved in the less symptomatic (+1.49°C), but did not change in the most symptomatic group (−0.12°C). However, the more symptomatic group had higher temperatures at the initial test, thus qualifying the result.

Conclusions:Skin temperature recovery after cold challenge in subjects with VWF remains reduced in the symptomatic subjects several years after exposure removal. This is evident even when blood pressure has increased in the setting of cold provocation. Results suggest that in VWF, the dermal circulation remains impaired, even after the restoration of arterial blood pressure in the digits.
ENERGY SPECTRUM OF THE GROUND STATE OF A TWO-DIMENSIONAL RELATIVISTIC HYDROGEN ATOM IN THE PRESENCE OF A CONSTANT MAGNETIC FIELD
Authors: VILLALBA VÍCTOR M. , PINO RAMIRO
Published: November 2003

We compute the energy spectrum of the ground state of a 2D Dirac electron in the presence of a Coulomb potential and a constant magnetic field perpendicular to the plane where the the electron is confined. With the help of a mixed-basis variational method we compute the wave function and the energy level and show how it depends on the magnetic field strength. We compare the results with those obtained numerically as well as in the non-relativistic limit.
AB-INITIO CALCULATIONS OF NMR PARAMETERS IN CONDENSED PHASES
Authors: SEBASTIANI DANIEL
Published: November 2003

We review the development of electronic structure methods for the calculation of nuclear magnetic resonance (NMR) properties in condensed matter over the last years. The key element is the extension of well-established approaches for the calculation of magnetic linear response to extended systems which are described under periodic boundary conditions. So far, two implementations have emerged which enable the calculation of NMR parameters within density functional theory in a pseudopotential plane wave scheme. We present the theoretical basis of the methods, further recent developments and a variety of selected applications. These applications are accompanied by comparisons with solid-state NMR experiments, exhibiting the strong impact of the symbiotic combination of high-level ab-initio calculations with experimental research.
Accessing the Literature: Using Bibliographic Databases to Find Journal Articles. Part 1
Authors: Marlborough Helen S
Published: November 2003

Research in primary dental care, re-certification, continuing professional development, lifelong learning, peer review and quality healthcare are all informed by the published literature. Dental practitioners can find out about reliable and up-to-date information available in the published literature by searching bibliographic databases. Published in two parts, this article describes the databases relevant to clinical dental practice and explains the generic skills required to search them effectively, focusing on MEDLINE, the database most relevant for the majority of dental practitioners, which is freely available via the World Wide Web (WWW). The article differentiates between sensitivity (maximum recall) and specificity (relevance of recall), and suggests how to identify a manageable number of relevant citations, how to save the citations, and how to obtain the full text. In part 2, the article concludes by alerting readers to some of the limitations and pitfalls of database-searching.
Visual Standards in a Sample of Dentists Working within Scotland
Authors: Forgie Andrew H , Gearie Tracy , Pine Cynthia M , Pitts Nigel B
Published: November 2003

Introduction

This study aims to measure the visual acuity of practising dentists and to establish the average time elapsed since their last routine eye examination.

Materials and methods

Distance visual acuity, near visual acuity, convergence, accommodation, contrast sensitivity, heterophorias and stereoscopic vision were measured in a diverse group of 46 dentists practising in Scotland.

Results

The results indicated that distance visual acuity was at least 6/6 for all but one of the subjects. All had acceptable near visual acuity. Accommodation followed the expected age-related trend of decreasing with age. No subjects had a definitely abnormal contrast sensitivity score although four were in the borderline zone. No subjects had a horizontal squint but two had a significant vertical phoria. Three subjects had no stereoscopic vision and one subject had a very high threshold level. All other subjects were able to see stereoscopically. Of the subjects 57% had been for an eye examination within the previous two years, with the range being from less than one month to 17 years.

Conclusion

The eyesight of this group of clinicians exceeds generally accepted normal population values. Although the majority of the clinicians had attended for an eye examination within two years, the large range of time since last attendance is of concern and regular eye examinations are to be encouraged.
Towards a theory of conscious art
Authors: Pepperell Robert
Published: November 2003

In this paper I argue that when we try to describe the specifically self-aware part of the mind, as opposed to the host of unconscious psychic activities, we face a potentially fatal difficulty - one I have termed ‘the inconceivability problem’. Because of the entanglement of the subject and the object in observations of subjectivity, and certain conceptual circularities, it seems we might never be able to represent the self-conscious mind with anything other than itself. This could leave consciousness studies in a very awkward position. In an attempt to address this I propose that the concept of infinite regression, which is normally associated with the ‘homuncular fallacy’, be reinterpreted productively, in a way that puts self-reference at the heart of our conception of phenomenal experience. Looking at several examples of self-referential systems and theories of mind, including Zen, it seems one system in particular - video feedback - offers a rich source of analogies that might help us to visualize, if not explain, the operation of ‘world-embedded’ self-consciousness. I explain that this inquiry is an attempt to build a theoretical foundation for the construction of a ‘conscious art’, by which I mean a type of art that is, to some extent, aware of itself and its surroundings.
Earning the Right to Indulge: Effort as a Determinant of Customer Preferences toward Frequency Program Rewards
Authors: Kivetz Ran , Simonson Itamar
Published: November 2003

Although frequency programs (FPs) have become ubiquitous in the marketplace and a key marketing-mix tool for promoting customer relationship and loyalty, little is known about the factors that determine how such programs are evaluated by consumers. The authors investigate the impact of the level of effort participants must invest to obtain the reward on the types of rewards they prefer and, consequently, on the decision to join the FP. In particular, the authors propose that higher required effort shifts consumer preferences from necessity to luxury rewards, because higher efforts reduce the guilt that is often associated with choosing luxuries over necessities. A series of studies with approximately 3100 consumers demonstrated that (1) higher program requirements shift preferences in favor of luxury rewards, (2) this effect is also observed when consumers choose between luxury and necessity rewards (of the same value) that they themselves proposed, and (3) the effect of program requirements on reward preferences is stronger among consumers who tend to feel guilty about luxury consumption and among those for whom the effort is invested in the context of work rather than pleasure. In addition, contrary to an alternative explanation based on the notion that higher requirements signal higher value of luxury rewards, the authors show that (1) when the program requirements are held constant but the individual consumer's effort is higher, the shift in preference toward luxuries is still observed and (2) increasing the monetary cost of participating in the FP decreases consumer preferences for luxury rewards. The authors discuss the theoretical implications of this research and the practical implications with respect to the design, targeting, and promotion of FPs.
Measuring Consumers' Willingness to Pay at the Point of Purchase
Authors: Wertenbroch Klaus , Skiera Bernd
Published: November 2003

Economists, psychologists, and marketing researchers rely on measures of consumers' willingness to pay (WTP) in estimating demand for private and public goods and in designing optimal price schedules. Existing market research techniques for measuring WTP differ in whether they provide an incentive to consumers to reveal their true WTP and in whether they simulate actual point-of-purchase contexts. The authors present an empirical comparison of several procedures for eliciting WTP that are applicable directly at the point of purchase. In particular, the authors test the applicability of Becker, DeGroot, and Marschak's (1964) well-known incentive-compatible procedure for assessing the utility of lotteries to measuring consumers' WTP. In three studies, the authors explore the reliability, validity, and feasibility of the procedure and show that it yields lower WTP estimates than do non-incentive-compatible methods such as open-ended and double-bounded contingent valuation. They show experimentally that differences in WTP estimates arise from the incentive constraint rather than the cognitive effort required in responding. They also control for strategic response behavior.
Fiber‐Optic Transmission
Authors: Freeman Roger L.
Published: November 2003

Fiber optics as a transmission medium offers such advantages in transmission that it has become the medium of choice for both terrestrial and undersea connectivities. From several perspectives it seems to have an infinite bandwidth. Operational systems support single serial bit streams of around 10 Gbps, and 40‐Gbps systems are on the horizon. A multiplying factor up to 45‐fold is available using dense wave division multiplexing such that a single fiber can transport 10 × 45 Gbps or 450 Gbps.

Fiber‐optic links prove‐in over very long distances, typically transcontinental, and over very short distances, on the order of 300 cm (i.e., 1 ft) and anywhere in between.

A fiber‐optic link consists of a light source (i.e., transmitter), fiber‐optic cable with connectors and/or splices, and a detector (i.e., receiver). Long fiber‐optic links require intermediate repeaters. The distance between repeaters is much greater than found in coaxial cable systems, and that distance is being notably extended with the use of erbium‐doped amplifiers.

There are two basic impairments to fiber‐optic transmission: fiber loss and dispersion.

This chapter provides fiber‐optic design and application information for transmission links. Data have been included that deal with generic fiber types, sources, detectors, splices/connectors, amplifiers, wave‐division multiplex, and system design and performance. The reader should appreciate that fiber‐optic technology continues to advance very rapidly.
Radio‐Frequency Data and Regulatory Information
Authors: Freeman Roger L.
Published: November 2003

The electromagnetic spectrum is a natural resource of the world. To achieve optimum utilization of this resource for the public good, it is rigidly regulated. The International Telecommunication Union, based in Geneva, Switzerland, is an international regulatory agency of which nearly every nation in the world is a member and thus a signatory of its
Radio Regulations
.

The “Radio Regulations” embody the regulatory material on which each national regulatory agency (e.g., Federal Communications Commission in the United States, for example) bases its own regulations, often with refinements. The World Administrative Radio Conference (WARC) meets periodically to revise the Radio Regulations. The last WARC was in 1997.

This chapter provides basic planning information regarding the electromagnetic spectrum and its regulated usage. Sources for this chapter are the 1990 Radio Regulations, revised in 1994 with an update in 1996, data from the U.S. National Telecommunications and Information Administration, and data from the Federal Communications Commission (FCC) (1996). Much of the FCC data provided are filed in the appropriate specialty chapter.
High‐Frequency (HF) Radio Systems
Authors: Freeman Roger L.
Published: November 2003

From about 1920 to around 1965, HF radio was the workhorse for long‐distance telecommunication connectivity. Today it serves as an adjunct and backup for more cost‐effective, high‐availability broadband systems. In many situations it can provide a primary means of communications for the world's armed forces.

HF radio operates in the frequency band 3–30 MHz. HF propagation and transmission techniques can be readily used down to 2 MHz and below. HF can be a very economic alternative for narrow‐band, long‐distance transmission. Up to 12‐kHz bandwidth is permitted supporting four nominal 3‐kHz voice channels. However, much of the utilization of HF is based on frequency shift keying (FSK) message transmission in the range of 50–150 bps. HF circuits are used for links up to or greater than 8000 km long. Propagation availabilities range from 70% to 90% or somewhat more. HF is widely used for international propaganda broadcasts. Some countries use parts of the lower HF band (e.g., around 6 MHz) for standard broadcast. Thus, more because of typical HF skywave propagation, the HF band is rampant with interference, which probably is its number one impairment.

The objective of this chapter is to provide design data on HF systems, favoring point‐to‐point operations. In this chapter expect to find data on required signal‐to‐noise ratios, bandwidths, fade margins, propagation predictions, HF system design requirements and specifications, frequency stability implications, digital data modulation plans and waveforms, and relative level of carrier in relation to peak envelope power (PEP).
Transmission Lines and Related Devices
Authors: Freeman Roger L.
Published: November 2003

The assemblage of data presented in this chapter deals with transmission lines and related information. A transmission line provides the conductive transport for carrying signal power between/among system elements.

From the 1950s to about 1985, coaxial cable was a major contender for long distance signal transport (e.g., AT&T L5 transcontinental system). Fiber‐optic systems are far more feasible, do not need equalization, and have lower loss and nearly an infinite bandwidth. They have completely replaced long‐distance coaxial cable systems. Coaxial cable is widely employed for the last mile (last kilometer) or last 100 ft (30 m) of cable television systems. It is almost universally used for comparatively short run transport of RF signals (e.g, connecting transmitter/receiver to antenna). However, its use is declining in the enterprise network.
Data Transmission
Authors: Freeman Roger L.
Published: November 2003

The objective of this chapter is to present a collection of system‐related information on data transmission. Essentially the chapter deals with the basic, generalized physical interface (i.e., OSI layer 1) of a data circuit.

Data communications is the fastest growing segment of telecommunications. Among the several new terms appearing after 1990 is the
enterprise network
. This is a network employing data transmission that is used in the office and industrial environment consisting of local area networks (LANs) and wide area networks (WANs). The underlying technology for the physical layer of these networks is data transmission. The transmission is binary based on the bit or 1s and 0s. Of primordial interest is the speed of transmission measured in bits per second (bps) and its underlying performance measure, the
bit error rate (or ratio)
(BER).

Data transmission has evolved from telegraph transmission, technology of the 1920s. Much of the terminology used to describe data transmission derives from telegraphy terms such as FSK (frequency shift keying), ARQ (automatic repeat request) and “marks and spaces.”

A major thrust of the chapter is the data modem, a device that makes the binary DC (direct current) format of 1s and 0s compatible with an analog connectivity or compatible with the digital voice channel (the 56/64‐kbps channel) via a device called a channel service unit/digital service unit (CSU/DSU).
Community Antenna Television (CATV)
Authors: Freeman Roger L.
Published: November 2003

Community antenna television (CATV) has come a long way since its beginnings in the 1960s. At that time, its thrust was entertainment by providing a customer a choice of multiple TV channels with comparatively good quality pictures. It is now going through a change providing the user with a return path. In other words, the system has changed from a one‐way to a two‐way system while maintaining the capability of multiple TV channels. This new approach is well along towards maturity, where a user can simultaneously have basic plain old telephone service (POTS) telephony, megabit Internet, various two‐way data services, and TV reception.

The chapter begins with a descriptive narrative, then includes an extensive table of channel assignments. These are the standardized 6 MHz frequency slots. This is followed by a review of the Digital Video Transmission Standard for Cable Television. Then there is an overview of data over cable service interface specification (DOCSIS). Work is completed on the IEEE 802.14 specification called the Multimedia Modem Protocol. A section of the chapter briefly reviews the protocol. The
IEEE Spectrum
(May 1999) forecasts a merger between DOCSIS and 802.14 specifications. The chapter then has several subsections dealing the CATV system design issues.
Emergency and Standby Power Systems for Telecommunications
Authors: Freeman Roger L.
Published: November 2003

Availability is one of the most important considerations in the design of a telecommunication system. In many instances, prime power outage is the single largest contributor to the degradation of availability. In addition, many computers and processors have volatile memory and depend on a constant voltage source to keep memories alive. With the loss of prime power, volatile memories may be lost and require reloading.

This chapter treats methods of ensuring continuous power. For a single computer this may only mean a small battery pack. On the other extreme is backup, no‐break power for the entire critical load of a large telecommunications facility. Telephone switching centers are good examples of such a large facility, and it is this group that has pioneered no‐break power. The basic supply for such a facility is −48 volts of
direct current
(
DC
) derived from large banks of secondary cells. Because of this no‐break source of power, other telephone equipment also depend on −48‐VDC power, such as transmission equipment (e.g., radio relay sets, multiplex equipment).

Other installations require 110/220‐VAC or similar sources to support the critical load. Some of these installations still depend on flywheel systems where the inertia of the flywheel (connecting a motor/generator to a diesel or gasoline engine) supplies power for the several‐second interval from the loss of prime power until the diesel or gasoline engine generator cam takes up the load. The inertia in the flywheel not only keeps the generator turning, but also cranks the gasoline or diesel engine. A more modern approach is the battery‐charger system described above with the addition of an inverter to produce 110/220 VAC.

We define
reserve time
as that time the battery supply can carry the full load. Reserve time can be measured in minutes when all that is required is to bring on‐line a backup generator. It can be measured in hours — enough time for a technician to travel to a remote site to bring up a backup generator, or statistically the reasonable maximum time of a power outage.

This chapter provides the reader with the design details to assemble a backup power system with reasonable system parameters. Designing a system with excessive reserve time is costly. The amount of reserve time is a judgment call on the system designer.
Sensor Array Technology, Army
Authors: Schoess Jeffrey
Published: November 2003

Today's commercial and military aircraft require significant manpower to provide operational readiness and flight safety. Aging aircraft fleets are much in need of new and innovative health‐monitoring methods to prevent catastrophic failure and reduce life‐cycle costs. The key needs for characterizing

in situ

structural integrity characteristics of corrosion and barely visible impact damage (BVID) to determine “damage susceptibility” must be addressed. This article presents a new concept for onboard real‐time monitoring using conductive polymer sensor array technology.
Battery Applications
Authors: Manthiram Arumugam
Published: November 2003

Batteries are the major power sources for portable electronic devices and toys. They are also used in automobiles for starting, lighting, and ignition (SLI batteries). At present, the worldwide battery market exceeds $30 billion per year. Rapid technological advances and miniaturization in electronics have created an ever‐increasing demand for compact, lightweight batteries. For example, popular portable electronic devices such as cellular phones, laptop computers, and camcorders require batteries of high energy density. Additionally, a need for more efficient use of available energy resources as well as air‐quality control have created enormous interest in electric vehicles. For example, the major automobile manufacturers around the globe are engaged in developing advanced batteries for electric vehicles in response to increased environmental regulations and legislative mandates. The advanced and high energy density batteries have become possible due to the discovery and development of smart materials and processes. This article, after providing a brief introduction to the basic electrochemical concepts and the principles involved in batteries, presents the materials and electrochemical aspects of high energy density (lithium‐ion) batteries.
Chemical Indicating Devices
Authors: Oriakhi Christopher O.
Published: November 2003

Most people remember a chemical indicator from their high school chemistry. This kind of indicator is a material that changes color to signify the end point of a titration or to provide a relative indication of the acidity or alkalinity of a chemical substance. The use of indicators extends far beyond this. For example, food, cosmetic, pharmaceutical, and other chemical formulations undergo complex chemical, enzymatic, and microbial interactions when they are exposed to UV light or temperature fluctuations over time. Consequently, product quality may be degraded and may lead to additional safety concerns. The challenges facing the produce industry include successful implementation of Good Manufacturing Practices (GMP), Hazard Analysis and Critical Control Point (HACCP), Total Quality Management (TQM) programs, and other regulations that demand compliance.

To address these issues and increase consumer confidence in product quality, safety, and authenticity, many manufacturers incorporate inexpensive monitoring devices into their products during production, packaging, or storage. A large number of consumer‐readable indicators are available commercially.

Generally, chemical indicators may be defined as stimulus responsive materials that can provide useful information about changes in their environment. Organic dyes, hydrogels or “smart polymers,” shape‐memory alloys, thermochromic or photochromic inks, and liquid crystals are some examples. They may function by forming structurally altered ionic or molecular complexes with species in their environment through chemical or physical interactions involving proton exchange, chelation, hydrogen bonding, dipole–dipole interactions, or van der Waal forces. The resulting characteristic biochemical, chemical, optical, magnetic, thermal, or mechanical changes can be tailored to provide the desired indication response.

This article focuses on inexpensive disposable chemical indicating devices such as pH indicators, temperature indicators, time–temperature indicators (TTI), and tampering and counterfeit indicators. The temperature and TTIs are widely used in the food and pharmaceutical products where date coding on a package may sometimes be inadequate.
Ceramics, Piezoelectric and Electrostrictive
Authors: Kholkin Andrei , Jadidian Bahram , Safari Ahmad
Published: November 2003

In a rapidly developing world, the use of smart materials becomes increasingly important when executing sophisticated functions within a designed device. In a common definition, smart materials differ from ordinary materials because they can perform two or several functions, sometimes with a useful correlation or feedback mechanism between them. For piezoelectric or electrostrictive materials, this means that the same component may be used for both sensor and actuator functions. Piezoelectric/electrostrictive sensors convert a mechanical variable (displacement or force) into a measurable electrical quantity by the piezoelectric/electrostrictive effect. Alternately, the actuator converts an electrical signal into a useful displacement or force. Typically, the term transducer is used to describe a component that serves actuator (transmitting) and sensor (receiving) functions. Because piezoelectrics and electrostrictors inherently possess both direct (sensor) and converse (actuator) effects, they can be considered smart materials. The degree of smartness can vary in piezoelectric/electrostrictive materials. A merely smart material (only sensor and actuator functions) can often be engineered into a “very smart” tunable device or further, into an “intelligent structure” whose sensor and actuator functions are intercorrelated with an integrated processing chip.

Recent growth in the transducer market has been rapid and, it is predicted will continue on its current pace through the turn of the century. Piezoelectric/electrostrictive sensors and actuators comprise a significant portion of the transducer market. There is a growing trend due especially to automobile production, active vibration damping, and medical imaging. In this article, the principles of piezoelectric/electrostrictive sensors and actuators are considered along with the properties of the most useful materials and examples of successful devices.