bluuebunny/crossref_metadata_2025 huggingface dataset:
The LRLTRAN compiler
Authors: Mendicino Sam F. , Hughes Robert A. , Martin Jeanne T. , McMahon Frank H. , Ranelletti John E. , Zwakenberg Richard G.
Published: July 2002

Extensive software problems confront an organization which possesses a number of different computers and which frequently acquire new ones. To maintain cohesion, a system must be developed, written in a high level language, which minimizes machine dependencies and isolates those which are necessary. A language and a compiler for that language are discussed here.

The language, called LRLTRAN, is a heavily augmented FORTRAN. The three-pass compiler makes use internally of a postfix Polish notation (pass I to pass II) and a free representation referred to as a “composite blocking table” (pass I to pass III). Machine-independent optimization occurs in pass II and DO-loop and machine-dependent optimization in pass III.
A phonological rule tester
Authors: Bobrow Daniel G. , Fraser J. Bruce
Published: July 2002

Theoretical and practical values of error coefficients useful in bounding the error in integrating periodic analytic functions with the trapezoidal rule are tabulated for various ranges of the parameters.
On conjunctive queries containing inequalities
Authors: Klug Anthony
Published: July 2002

Conjunctive queries are generalized so that inequality comparisons can be made between elements of the query. Algorithms for containment and equivalence of such “inequality queries” are given, under the assumption that the data domains are dense and totally ordered. In general, containment does not imply the existence of homomorphisms (containment mappings), but the homomorphism property does exist for subclasses of inequality queries. A minimization algorithm is defined using the equivalence algorithm. It is first shown that the constants appearing in a query can be divided into “essential” and “nonessential” subgroups. The minimum query can be nondeterministically guessed using only the essential constants of the original query.
Finding a maximum-genus graph imbedding
Authors: Furst Merrick L. , Gross Jonathan L. , McGeoch Lyle A.
Published: July 2002

The computational complexity of constructing the imbeddings of a given graph into surfaces of different genus is not well understood. In this paper, topological methods and a reduction to linear matroid parity are used to develop a polynomial-time algorithm to find a maximum-genus cellular imbedding. This seems to be the first imbedding algorithm for which the running time is not exponential in the genus of the imbedding surface.
Minerva
Authors: Alvarez Guillermo A. , Borowsky Elizabeth , Go Susie , Romer Theodore H. , Becker-Szendy Ralph , Golding Richard , Merchant Arif , Spasojevic Mirjana , Veitch Alistair , Wilkes John
Published: July 2002

Enterprise-scale storage systems, which can contain hundreds of host computers and storage devices and up to tens of thousands of disks and logical volumes, are difficult to design. The volume of choices that need to be made is massive, and many choices have unforeseen interactions. Storage system design is tedious and complicated to do by hand, usually leading to solutions that are grossly over-provisioned, substantially under-performing or, in the worst case, both.To solve the configuration nightmare, we present minerva: a suite of tools for designing storage systems automatically. Minerva uses declarative specifications of application requirements and device capabilities; constraint-based formulations of the various sub-problems; and optimization techniques to explore the search space of possible solutions.This paper also explores and evaluates the design decisions that went into Minerva, using specialized micro- and macro-benchmarks. We show that Minerva can successfully handle a workload with substantial complexity (a decision-support database benchmark). Minerva created a 16-disk design in only a few minutes that achieved the same performance as a 30-disk system manually designed by human experts. Of equal importance, Minerva was able to predict the resulting system's performance before it was built.
Discrete smooth interpolation
Authors: Mallet Jean-Laurent
Published: July 2002

Interpolation of a function ƒ (.) known at some data points of

R
P

is a common problem. Many computer applications (e.g., automatic contouring) need to perform interpolation only at the nodes of a given grid. Whereas most classical methods solve the problem by finding a function defined everywhere, the proposed method avoids explicitly computing such a function and instead produces values only at the grid points. For two-dimensional regular grids, a special case of this method is identical to the Briggs method (see “Machine Contouring Using Minimum Curvature,”
Geophysics 17
, 1 (1974)), while another special case is equivalent to a discrete version of thin plate splines (see J. Duchon,
Fonctions Splines du type Plaque Mince en Dimention 2
, Séminaire d'analyse numérique, n 231, U.S.M.G., Grenoble, 1975; and J. Enriquez, J. Thomann, and M. Goupillot, Application of bidimensional spline functions to geophysics,
Geophysics 48
, 9 (1983)).
Hierarchical planarity testing algorithms
Authors: Lengauer Thomas
Published: July 2002

Using hierarchical definitions, one can describe very large graphs in small space. The blow-up from the length of the hierarchical description to the size of the graph can be as large as exponential. If the efficiency of graph algorithms is measured in terms of the length of the hierarchical description rather than in terms of the graph size, algorithms that do not exploit the hierarchy become hopelessly inefficient. Whether the hierarchy can be exploited to speed up the solution of graph problems depends on the hierarchical graph model. In the literature, hierarchical graph models have been described that allow almost no exploitation of the hierarchy [ 16]. In this paper, a hierarchical graph model that permits taking advantage of the hierarchy is presented. For this model algorithms are given that test planarity of a hierarchically described graph in linear time in the length of the hierarchical description.
Acyclic fork-join queuing networks
Authors: Baccelli François , Massey William A. , Towsley Don
Published: July 2002

In this paper the class of acyclic fork-join queuing networks that arise in various applications, including parallel processing and flexible manufacturing are studied. In such queuing networks, a fork describes the simultaneous creation of several new customers, which are sent to different queues. The corresponding join occurs when the services of all these new customers are completed. The evolution equations that govern the behavior of such networks are derived. From this, the stability conditions are obtained and upper and lower bounds on the network response times are developed. These bounds are based on various stochastic ordering principles and on the notion of association of random variables.
Using histories to implement atomic objects
Authors: Ng Tony P.
Published: July 2002

In this paper we describe an approach to implementing atomicity. Atomicity requires that computations appear to be all-or-nothing and executed in aserialization order. The approach we describe has three characteristics. First, it utilizes the semantics of an application to improve concurrency. Second, it reduces the complexity of application-dependent synchronization code by analyzing the process of writing it. Third, our approach hides the protocol used to arrive at a serialization order from the applications. As a result, different protocols can be used without affecting the applications. Our approach uses a history abstraction. The history captures the ordering relationship among concurrent computations. By determining what types of computations exist in the history and their parameters, a computation can determine whether it can proceed.
Europe 1992: fraternity or fortress?
Authors: Jeelof Gerrit
Published: July 2002

The following 1989 William K. McInally Memorial lecture was presented at the University of Michigan by Gerrit Jeelof, a champion of the movement toward European enconomic unity. He discusses the upcoming European integration and its implications for world trade.
A cross-cultural comparison of IS designer values
Authors: Kumar Kuldeep , Bjorn-Andersen Niels
Published: July 2002

The values of system designers have a significant influence on the extent to which information system meet the broad effectiveness needs of an
organization.
MEMBRANE TRANSPORT CARRIERS
Authors: Tanner W. , Caspari T.
Published: July 2002

▪ Abstract  Plant and fungal membrane proteins catalyzing the transmembrane translocation of small molecules without directly using ATP or acting as channels are discussed in this review. Facilitators, ion-cotransporters, and exchange translocators mainly for sugars, amino acids, and ions that have been cloned and characterized from Saccharomyces cerevisiae and from various plant sources have been tabulated. The membrane topology and structure of the most extensively studied carriers (lac permease of Escherichia coli, Glut1 of man, HUP1 of Chlorella) are discussed in detail as well as the kinetic analysis of specific Na+and H+cotransporters. Finally, the knowledge concerning regulatory phenomena of carriers—mainly of S. cerevisiae—is summarized.
CYTOKINESIS AND BUILDING OF THE CELL PLATE IN PLANTS
Authors: Verma Desh Pal S
Published: July 2002

▪ Abstract  Cytokinesis in plant cells is more complex than in animals, as it involves building a cell plate as the final step in generating two cells. The cell plate is built in the center of phragmoplast by fusion of Golgi-derived vesicles. This step imposes an architectural problem where ballooning of the fused structures has to be avoided to create a plate instead. This is apparently achieved by squeezing the vesicles into dumbbell-shaped vesicle-tubule-vesicle (VTV) structures with the help of phragmoplastin, a homolog of dynamin. These structures are fused at their ends in a star-shaped body creating a tubulovesicular “honeycomb-like” structure sandwiched between the positive ends of the phragmoplast microtubules. This review summarizes our current understanding of various mechanisms involved in budding-off of Golgi vesicles, delivery and fusion of vesicles to initiate cell plate, and the synthesis of polysaccharides at the forming cell plate. Little is known about the molecular mechanisms involved in determining the site, direction, and the point of attachment of the growing cell plate with the parental cell wall. These gaps may be filled soon, as many genes that have been identified by mutations are analyzed and functions of their products are deciphered.
It All Started on a Streetcar in Boston
Authors: Tabor Celia White , Tabor Herbert
Published: July 2002

We first met on a Boston streetcar in 1940, being introduced by a mutual friend. Celia was returning from research work at the Massachusetts General Hospital as part of her senior thesis at Radcliffe College, and Herb was returning from a concert by the Boston Symphony. We were married in 1946 after Celia had finished her medical training. We started working together in 1952, and we are still actively collaborating in our studies on various aspects of the biosynthesis and function of polyamines. We are honored to have been invited by the editors of the Annual Review of Biochemistry to summarize our activities in biochemical research over the past 60 years. During most of this time we have been at the National Institutes of Health in Bethesda, Md., and we have witnessed the enormous expansion of biomedical research that has occurred during this period. In addition to summarizing our research, Herb summarizes his association with the Journal of Biological Chemistry and the remarkable developments that have occurred recently in electronic publication and dissemination of scientific literature.
MICROBIAL DIVERSITY: Domains and Kingdoms
Authors: Williams David M. , Embley T. Martin
Published: July 2002

▪ Abstract  With the discovery of the eukaryote nucleus, all living organisms were neatly divided into prokaryotes, which lacked a nucleus, and eukaryotes, which possessed it. As data derived directly from the genome became available, it was clear that prokaryotes were comprised of two groups, Eubacteria and Archaebacteria. These were subsequently renamed at the new taxonomic level of Domain as Bacteria and Archaea, with the eukaryotes named as the Eucarya Domain. The interrelationships of the three Domains are still subject to discussion and evaluation, as is their monophyly. Further data, drawn from various protein sequences, suggest conflicting schemes, and resolution may not be straightforward. Additionally, Bacteria and Archaea as well as Eucarya are largely based on organisms already in culture. Investigation of the potentially enormous quantity of uncultured organisms in nature is likely to have as broad-ranging implications as the exploration of new protein sequences.
Analysis of Selection on Enzyme Polymorphisms
Authors: Eanes Walter F.
Published: July 2002

▪ Abstract  Allozyme polymorphisms have been the focus of studies of selection at single enzyme loci, and most involve the enzymes of central metabolism. DNA sequencing of enzyme loci has shown numerous examples of multiple amino acid polymorphisms segregating within electromorphs. The amino acid heterogeneity underlying many allozyme polymorphisms should confound analysis of functional differences and selection. Metabolic control theory proposed that pathways will be insensitive to functional changes in allozymes; however, there is evidence that many polymorphisms modulate fluxes. Studies of model systems have provided detailed evidence for selection acting on enzyme polymorphisms in metabolic genes. There is also evidence that regulatory changes are superimposed on structural changes. Codon bias implies that the functional differences encountered in allozyme studies should be detectable by natural selection; however, amino acid polymorphisms may also represent weakly deleterious mutations. Future studies should connect structural changes with effects on function and stability, and they should emphasize the multilocus nature of responses to selection.
Evolutionary Patterns Among Permo-Triassic Therapsids
Authors: Rubidge Bruce S. , Sidor Christian A.
Published: July 2002

▪ Abstract  A rich fossil record documents nonmammalian evolution. In recent years, the application of cladistic methodology has shed valuable light on the relationships within the therapsid clades Biarmosuchia, Dinocephalia, Anomodontia, and Cynodontia. Recent discoveries from South Africa suggest that Gondwana, rather than Laurasia, was the center of origin and radiation for many early therapsids. Because of their relative abundance and global distribution, therapsids have enjoyed widespread use in biostratigraphy, basin analysis, and paleo-environmental and -continental reconstructions. Synapsids (including therapsids) form the bulk of tetrapod diversity (in terms of both number of species and abundance) from Early Permian to Middle Triassic times and thus can provide critical information on the nature of the Permo-Triassic extinction in the terrestrial realm. Quantitative techniques have produced headway into understanding the relative importance of homoplasy and convergent evolution in the origin of mammals.
Impact of the Internet on Entomology Teaching and Research
Authors: Zenger J. T. , Walker T. J.
Published: July 2002

▪ Abstract  The Internet is affecting entomology teaching and research. Internet tools help students communicate and easily find and access information. Entomology instructors who adopt these tools may discover they are surprisingly time consuming to implement. Requiring students to use the Internet teaches them to glean from the glut of available information and to communicate electronically, both vital skills in today’s workplace. The Internet helps meet the growing need for distance education by providing a medium that allows students to conveniently access course materials and to communicate with the instructor and other students. Researchers benefit from using the Internet for one-to-one and one-to-many communication and from access to large cooperative databases, for example, in molecular biology and systematics. Perhaps the greatest impact on research will be the migration to the Web of journals and other specialized research literature. This may permit free access and will change the content and format of journal articles.
REDUCED-SIZE HEPATIC ALLOGRAFTS
Authors: Malagó, M.D M. , Rogiers, M.D X. , Broelsch, M.D., Ph.D C.E.
Published: July 2002

▪ Abstract  Reduced-size hepatic transplantation (RSHT) was developed to alleviate the mortality resulting from the scarcity of suitable cadaveric grafts. RSHT consists of various techniques that reduce a full liver to a smaller size. These techniques include reduced-size cadaveric liver transplantation (RLT), split liver transplantation (SLT), and living-related liver transplantation (LRLT). RLT utilizes part of a liver, while the rest is discarded; in SLT, the whole liver is used for two recipients after bipartition; and in LRLT, a portion of the liver retrieved from a living donor is transplanted. Whereas RLT only redistributes the pool of organs to the advantage of pediatric recipients, both SLT and LRLT increase the availability of grafts for transplantation. RSHT yields results comparable to full-liver allografting and drastically reduces the mortality of patients waiting for transplantation. The procedures involved are technically demanding and should be restricted to experienced liver centers.
PHYSICS OPPORTUNITIES OFe+e−LINEAR COLLIDERS
Authors: Murayama Hitoshi , Peskin Michael E.
Published: July 2002

▪ Abstract  We describe the anticipated experimental program of an e+e−linear collider in the energy region 500 GeV—1.5 TeV, emphasizing topics relevant to the mystery of electroweak symmetry breaking.
METABOLIC LESSONS FROM GENETICALLY LEAN MICE
Authors: Reitman Marc L.
Published: July 2002

▪ Abstract  Different types of lean mice have been produced by genetic manipulation. Leanness can result from deficiency of stored energy or a lack of adipocytes to store the lipid. Mice lacking functional adipocytes are usually insulin resistant and have fatty livers, and elevated circulating triglyceride levels. Insulin resistance may result from the lack of adipocyte hormones (such as leptin) and increased metabolite (such as triglyceride) levels in nonadipose tissue. Mice with depleted adipocyte triglyceride levels typically are insulin sensitive and have normal or low liver and circulating triglycerides. Mechanisms to produce depleted adipocytes include increased energy expenditure by peripheral tissues, peripheral mechanisms to decrease food intake, and altered central regulation of these processes.
Molecular Chaperones in the Kidney
Authors: Borkan Steven C. , Gullans Steven R.
Published: July 2002

▪ Abstract  The normal milieu of the kidney includes hypoxia, large osmotic fluxes, and an enormous amount of fluid/solute reabsorption. Renal adaptation to these conditions requires a host of molecular chaperones that stabilize protein conformation, target nascent proteins to their final intracellular destination, and prevent protein aggregation. Under physiologic or pharmacologic stress, inducible molecular chaperones provide additional mechanisms for repairing or degrading non-native proteins and for inhibiting stress-induced apoptosis. In contrast to intracellular chaperones, chaperones present on the cell surface regulate the immune system and have cytokine-like effects. A diverse range of chaperones and chaperone functions provide the renal cell with an armamentarium of responses to improve the chances of survival.
Personnel Policy and Racial Inequality in the Pre-World War II North
Authors: Maloney Thomas N.
Published: July 2002

Hundreds of thousands of African-Americans left the southern United States for the North between World War I and World War II. The willingness of employers in northern industries to “experiment” with this new labor pool depended on the training, turnover, and promotion policies that characterized their internal labor markets.
Mnemonic Notations: A Decade of Art Practice within a Digital Environment
Authors: George Phillip
Published: July 2002

The author's work Mnemonic Notations represents the evolution of one computer graphic file, first generated in 1990. The author has modified the file for over a decade in response to exposure to many ideas and influences. The Mnemonic Notations file has been output and visually represented as paintings and prints. Mnemonic Notations files were also used as the basis of the Mnemonic Notations CD-ROMs and interactive installations, as well as digital photographic works dealing with fictional documentations.
The Corporeal Stenographer: Language, Gesture, and Cyberspace
Authors: Holmes Tiffany
Published: July 2002

The author describes her research and creative practice exploring the intersection between digital, biomedical, and linguistic modes of bodi ly representation. She synthesizes traditional forms of painting with new computer and medical imaging technologies to call into question the relationship between visible and invisible bodily forms and actions. Her paintings and installations use scientifically rendered images of the body (from symbolic DNA sequences to developing cel lular structures) in order to consider the role of the tools and technologies used to organize and view these images. The issue of visual, linguistic, and scientific literacy is thus a corollary concern.
Stable Encoding of Finite-State Machines in Discrete-Time Recurrent Neural Nets with Sigmoid Units
Authors: Carrasco Rafael C. , Forcada Mikel L. , Valdés-Muñoz M. Ángeles , Ñeco Ramón P.
Published: July 2002

There has been a lot of interest in the use of discrete-time recurrent neural nets (DTRNN) to learn finite-state tasks, with interesting results regarding the induction of simple finite-state machines from input–output strings. Parallel work has studied the computational power of DTRNN in connection with finite-state computation. This article describes a simple strategy to devise stable encodings of finite-state machines in computationally capable discrete-time recurrent neural architectures with sigmoid units and gives a detailed presentation on how this strategy may be applied to encode a general class of finite-state machines in a variety of commonly used first- and second-order recurrent neural networks. Unlike previous work that either imposed some restrictions to state values or used a detailed analysis based on fixed-point attractors, our approach applies to any positive, bounded, strictly growing, continuous activation function and uses simple bounding criteria based on a study of the conditions under which a proposed encoding scheme guarantees that the DTRNN is actually behaving as a finite-state machine.
Efficient Block Training of Multilayer Perceptrons
Authors: Navia-Vázquez A. , Figueiras-Vidal A. R.
Published: July 2002

The attractive possibility of applying layerwise block training algorithms to multilayer perceptrons MLP, which offers initial advantages in computational effort, is refined in this article by means of introducing a sensitivity correction factor in the formulation. This results in a clear performance advantage, which we verify in several applications. The reasons for this advantage are discussed and related to implicit relations with second-order techniques, natural gradient formulations through Fisher's information matrix, and sample selection. Extensions to recurrent networks and other research lines are suggested at the close of the article.
Bias/Variance Decompositions for Likelihood-Based Estimators
Authors: Heskes Tom
Published: July 2002

The bias/variance decomposition of mean-squared error is well understood and relatively straightforward. In this note, a similar simple decomposition is derived, valid for any kind of error measure that, when using the appropriate probability model, can be derived from a Kullback-Leibler divergence or log-likelihood.
Natural Gradient Learning for Over- and Under-Complete Bases in ICA
Authors: Amari Shun-ichi
Published: July 2002

Independent component analysis or blind source separation is a new technique of extracting independent signals from mixtures. It is applicable even when the number of independent sources is unknown and is larger or smaller than the number of observed mixture signals. This article extends the natural gradient learning algorithm to be applicable to these overcomplete and undercomplete cases. Here, the observed signals are assumed to be whitened by preprocessing, so that we use the natural Riemannian gradient in Stiefel manifolds.
Evolution of Time Coding Systems
Authors: Carr C. E. , Friedman M. A.
Published: July 2002

The auditory and electrosensory systems contain circuits that are specialized for the encoding and processing of microsecond time differences. Analysis of these circuits in two specialists, weakly electric fish and barn owls, has uncovered common design principles and illuminated some aspects of their evolution.
“You Are Here”: The DNA of Performance
Authors: Taylor Diana
Published: July 2002

Among the mothers and the children of the “disappeared” in Argentina, performance of various kinds is a way of marking, accusing, and remembering. How can performance transmit traumatic memory? How do those of us who have not suffered the violence come to understand it? And how do we participate, in our own ways, in further transmitting it?
Ohmage to Resistance
Authors: Lipschutz Ronnie D.
Published: July 2002

This essay disputes the arguments made by Robert Paehlke and John Dryzek in their contributions to this issue of Global Environmental Politics. Both reform and resistance are necessary, but not sufficient, elements in collective efforts to facilitating global and local environmental protection and sustainable development. What is essential, as well, are campaigns to establish alternative institutional frameworks for the fulfillment of these goals. This essay suggests that initiatives such as those found around the issue of sustainable forestry practices might be the basis for such frameworks and, in the long run, could pressure both capital and governments to agree on strengthened and effective systems of public environmental regulation. The essay also notes the so-called democratic deficit among non-governmental organizations and movements, but questions whether there is any democracy among capitals and international institutions.
The Organization of the Impossible
Authors: Moltke Konrad von
Published: July 2002

Proposals for the creation of a World Environment Organization (WEO) are considered in light of the wide range of arrangements for environmental management at the national level. Organizational difficulties are compounded at the international level, suggesting that a WEO is neither possible nor desirable. Proposals to improve international environmental management must consider not only the weaknesses of current arrangements but also the sources of their effectiveness. Carefully designed steps to strengthen the institutions of international environmental management are desirable. Organizational proposals, other than strengthening the United Nations Environment Programme (UNEP), are a diversion from the pressing international environmental agenda.
The Case of Theaetetus
Authors: Adalier Gokhan
Published: July 2002

Any comprehensive interpretation of the Theaetetus has to provide answers to, among others, two very general questions concerning that dialogue: "What is Plato's relation to the problems faced in the Theaetetus?" and "What is the significance of the absence of the Forms from the discussion of the Theaetetus, given their undoubted relevance to the topic of the dialogue, i.e. knowledge?" Predominantly, the answer given to the first question in the literature has been that the problems are those that Plato is trying to tackle and the one to the second question, when it has been addressed at all, that the Forms are left out of the discussion because Plato no longer thought them relevant, either for having abandoned or seriously revised them, by the time of writing the Theaetetus. In this study of the Wax Block and the Aviary models of judgment that occur in the second part of the Theaetetus as part of its discussion of the problem of false judgment, I argue that the problems faced there actually arise because of the neglect of Forms. The discussion of the second part is, I contend, carried out on a materialist ontology, an ontology assumed because it suits the definition of knowledge as true judgment which inaugurates that part of the dialogue, an ontology in no way subscribed to by Plato. The Wax Block is, I explain, a materialist model and fails in the case of judgments about numbers for treating them on a par with material subjects, ignoring their intelligible status. In particular, it fails to distinguish judging 5 and 7 to be 11 from judging 12 to be 11 because of its neglect of Forms; Plato would distinguish those judgments by distinguishing 5 and 7 from 12 with help from his part-whole analysis, to which the Forms are essential.
Themistius on Evil
Authors: Guldentops Guy
Published: July 2002

Although Themistius does not develop a theodicy, his observations on evil are fairly consistent. Both in his paraphrases of Aristotle and in his speeches, he argues that since God is the intelligent and powerful cause of all good things in the universe, evil is due to the στ ρησιsigma in matter and to the νοια of human beings. Despite some (Neo-)Platonic and Stoic influences, Themistius defends a basically Peripatetic world-view, in which evil is minimized.
TRADE OFFS IN HABITAT-SPECIFIC FORAGING EFFICIENCY AND THE NASCENT ADAPTIVE DIVERGENCE OF STICKLEBACKS IN LAKES
Authors: Robinson Beren
Published: July 2002

I assessed habitat-specific foraging efficiency of shallow-water and open-water forms from a morphologically variable population of threespine sticklebacks. Individuals sampled from open-water or shallow-water habitats tend to be morphologically divergent, although the morphology of the modal form is intermediate between the better-known benthic and limnetic pairs of stickleback species that coexist in other local lakes. I tested two hypotheses about this intraspecific variation. First, that heritable genetic variation in body form exists between forms. Morphological differences occurred between progeny reared under common laboratory conditions indicating that heritable genetic variation contributes to morphological variation. Second, that open-water and shallow-water forms face trade offs involving foraging on habitat-specific prey. The foraging efficiency of both forms was measured in two types of habitat (benthos and open-water) simulated in lab aquaria. Foraging efficiency was related to morphological differences between morphs. Relative morph efficiencies were reversed between habitats in a predictable fashion. More streamlined open-water forms consumed Artemia nauplii at a higher rate and with fewer bites than more robust shallow-water morphs. Conversely, shallow-water morphs required fewer bites to capture and consume more and larger amphipods than open-water forms. An asymmetry in the trade offs indicates that shallow-water types may be the more specialized form. These results are consistent with a hypothesis that trade offs in habitat use efficiency can be involved early in the adaptive divergence of sticklebacks into different lake environments. Similar trade offs exist for the coexisting pairs of stickleback species, suggesting that trade offs are more likely a cause, rather than a consequence, of speciation in sticklebacks that colonize lakes.
Patterns and processes in the evolution of animal parasitic nematodes
Authors: Ley Paul De , Dorris Mark , Blaxter Mark
Published: July 2002

The parasitic Nematoda have traditionally been classified distinct from free-living species, and animal parasites treated separately from plant parasites. In classical concepts of phylogenetic relationships within the phylum, parasitic groups are usually afforded ordinal status and their origins are often obscure. We have been using molecular phylogenetics to examine the interrelationships of animal parasites with free-living and plant-parasitic groups, and find that a new view of the origins and radiation of animal parasites is warranted. Using sequence from the nuclear small subunit ribosomal RNA gene, we have constructed an alignment that allows robust phylogenetic inference. With this dataset, we place the Strongylida as a monophyletic clade nested within the Rhabditina. The Ascaridida, Oxyurida and Spirurida are closely related, but currently have no clear closest free-living sister taxon. Strongyloides spp. are rooted in a radiation of cephalobid/tylenchid species. Where available, other sequences in general confirm these relationships. Les Nematoda parasites ont été traditionnellement classifiés séparément des espèces libres, les parasites d’animaux étant traités séparément des parasites de plantes. Suivant les concepts classiques des relations phylogénétiques à l’intérieur du phylum, les groupes parasites sont habituellement traités au niveau ordinal et leurs origines sont souvent inconnues. Utilisant la phylogénie moléculaire, les interrelations des parasites animaux avec les groupes d’espèces libres et parasites de plantes ont été étudiées conduisant à la conclusion qu’une nouvelle approche des origines et de l’évolution des parasites animaux est nécessaire. Sur la base de la petite sous-unité nucléaire du gène de l’ARN ribosomal, un alignement est proposé qui permet une inférence phylogénétique solide. Avec cet ensemble de données, les Strongylida sont considérés comme un clade monophylétique emboîté au sein des Rhabditina. Les Ascaridida, Oxyurida et Spirurida sont étroitement reliés, mais jusqu’à présent sans relation étroite claire avec des taxons de nématode libre. Les Strongyloides spp. ont évolué à partir des cephalobides/tylenchides. Lorsqu’elles sont disponibles, les données issues d’autres séquences confirment le plus souvent ces relations.
Insect aggregations and entomopathogenic nematode occurrence
Authors: Bečvář Stanislav , Mráček Zdeněk
Published: July 2002

Entomopathogenic nematodes of the family Steinernematidae may significantly reduce insect populations. They inhabit most terrestrial habitats and their prevalence can be influenced by biotic factors. Some sawfly species, the geometrid and noctuid moth complexes, and bibionid and sciarid flies characteristically aggregate as diapausing or hibernating larvae in the soil. A survey for entomopathogenic nematodes from habitats characterized by these aggregations was performed in the Czech Republic by collecting soil samples and utilizing Galleria traps in the laboratory. Steinernematids were recovered from 61 of 87 (70.1%) sampled localities. Seven Steinernema species, S. kraussei, S. feltiae, S. affine, S. intermedium, S. bicornutum and two designated as species B and F were identified. Among these, S. kraussei was prevalent in sawfly localities (77.8%) while, in winter moth localities, S. feltiae (55.6%) dominated and S. kraussei (22.2%) and S. affine (25.9%) were common. Soil-dwelling insect aggregations seem to provide an opportunity for entomopathogenic nematode multiplication.Les nématodes entomopathogènes de la famille des Steinernematidae peuvent réduire significativement les populations d'insectes. Ils occupent la plupart des habitats terrestres et leur prévalence peut être influencée par des facteurs biotiques. Quelques espèces de tenthrèdes move, des Géométrides et des aleurodes Noctuides, de même que les mouches Sciarides et Bibionides forment des aggrégats caractéristiques lorsque leurs larves sont en diapause ou hivernent dans le sol. Une enquête sur ces nématodes entomopathogènes dans des habitats caractérisés par ces aggrégations d'insectes a été réalisée en République tchèque en collectant des échantillons de sol et en utilisant au laboratoire des pièges à Galleria. Des Steinernematides ont été trouvés dans 61 des 87 (70,1%) des localités échantillonnées. Cinq espèces connues de Steinernema (S. kraussei, S. feltiae, S. affine, S. intermedium, S. bicornutum) et deux espèces désignées comme espèces B et F ont été identifiées. S. kraussei était prévalent dans les localités à tenthrèdes (77,8%) tandis que S. feltiae dominait dans les localités à arpenteuse tardive (55,6%) ou S. kraussei (22,2%) et S. affine (25,9%) apparaissaient communs. Les aggrégats d'insectes terricoles semblent ainsi offrir une situation propice à la multiplication des nématodes entomopathogènes.
Damage to melon (Cucumis melo L.) cv. Durango by Meloidogyne incognita in Southern California
Authors: Phillips Mark , Ploeg Antoon
Published: July 2002

The relationship between increasing Meloidogyne incognita inoculum density and the growth of melon plants in pots was well described by the Seinhorst model. The estimated tolerance level was not affected by the age of the plant at time of exposure to the nematodes, but minimum yields increased significantly when nematode inoculation was delayed until 2 weeks after seeding. Similarly, in field grown plants, melon fruit yields decreased with increasing pre-plant nematode levels. Tolerance levels estimated from the field study were one second stage juvenile (J2) per 200 g soil sampled before planting, and the estimated yield loss at high nematode densities was 65%. The yield loss resulted primarily from fewer fruits being harvested per plant, rather than from the fruits being smaller. This may be due to a redirection of plant nutrients towards sustaining the nematodes developing in the root systems, inhibiting fruit set. The results indicate that preventing immediate access of the nematodes to very young seedlings may prevent severe yield losses, but may also result in high populations at harvest.
Response of soil nematode fauna to naturally elevated CO2 levels influenced by soil pattern
Authors: Newton Paul C.D. , Yeates Gregor W. , Ross Des J.
Published: July 2002

As experimental elevation of CO2 in short-term experiments may produce
organic matter with decomposition characteristics different from those
produced under long-term equilibrated conditions, we sampled the soil
nematode fauna near a natural CO2 vent in Northland, New Zealand. Various
indices of the nematode fauna showed significant effects, with all being
significantly correlated with soil pH, microbial carbon and atmospheric CO2
across the 33 sampling points. There was a general decrease in nematode
abundance and diversity, but an increase in dominance and proportion of
bacterial-feeding nematodes with increasing atmospheric CO2 concentration.
However, when the nematode data from gley and organic soils present at the
site were differentiated most of the significant correlations were with soil
microbial carbon; they were positive in the organic soil but negative in the
gley soil. That these responses can be related to soil carbon and to
microbial carbon demonstrates that any general response to long-term CO2
enrichment represents an integration of specific responses by the soil biota
in the various soils present. Die Reaktion der Bodennematodenfauna auf durch
Bodenbedingungen beeinflusste naturlich erhohte CO2-Werte - Da eine
experimentelle Erhohung von CO2 in Kurzzeitversuchen organisches Material
erzeugen konnte, das andere Zersetzungseigenschaften hat als das unter
ausgeglichenen Langzeitbedingungen entstehende, haben wir die Nematodenfauna
in Bodenproben aus der Nahe eines naturlichen CO2-Austrittes in Northland,
Neuseeland untersucht. Bei mehreren Kennzeichen der Nematodenfauna zeigten
sich deutliche Wirkungen, die alle signifikant korreliert waren mit dem
Boden-pH, dem mikrobiellen Kohlenstoff und dem atmospharischen CO2, und zwar
quer durch alle 33 Entnahmestellen. Mit steigender Konzentration des
atmospharischen CO2 trat eine allgemeine Abnahme der Haufigkeit und der
Verschiedenartigkeit der Nematoden ein, aber eine Zunahme der Vorherrschaft
und des Anteils bakterienfressender Nematoden. Wenn aber die Nematodenwerte
von an einer Entnahmestelle vorhandenen Gley- und organischen Boden
vergleichen wurden, bestanden die meisten der signifikanten Beziehungen mit
dem mikrobiellen Kohlenstoff. Sie waren positiv im organischen Boden und
negativ im Gleyboden. Die Tatsache, dass diese Reaktionen zum
Bodenkohlenstoff und dem mikrobiellen Kohlenstoff in Beziehung gebracht
werden konnen zeigt, dass jede allgemeine Reaktion auf eine langfristige
Anreicherung von CO2 eine Integration spezischer Reaktionen durch die in den
verschiedenen Boden vorhandenen biotischen Faktoren darstellt.
Conventions of Madness:Bürgerlichkeitand the Asylum in theVormärz
Authors: Goldberg Ann
Published: July 2002

Soonafter his wife's incarceration in the Eberbach asylum in 1827, Herr S., a rector and soon to becomeGymnasiumprofessor in Weilburg, wrote to Philipp H. Lindpaintner, the asylum's director. The letter was about the pressing problem of his wife's illness, but, strangely, Herr S. spent a great deal of time chatting about himself — about his new position as professor; his recent salary raise; his new apartment “near the castle garden, where the Hofmarschal used to live”; his library; hisNaturalien-Kabinett(natural history collection), which will be put on display at theRathaus“for the use of schools and the enjoyment of the friends of nature and art.” Finally, Herr S. turned to the issue at hand: his wife's mental illness.
Fracturing, overpressure release and carbonate cementation in the Everest Complex, North Sea
Authors: Conybeare D. M. , Shaw H. F.
Published: July 2002

The Palaeocene Everest Complex, located in the Central Graben of the North Sea, comprises interbedded sandstones and mudrocks deposited in a submarine fan environment and overlies Cretaceous limestones. Depositional facies are the main influence on reservoir quality, although the latter is reduced significantly locally by ferroan calcite cementation, particularly in the lower part of the complex. Carbon and O stable isotope analyses have been made from cements in sandstones and mudrocks and from shear fractures and injection features within mudrock intervals. These indicate a marine source of detrital carbonate becoming mixed with HCO3− from decarboxylation higher in the succession. Petrographic observation and microprobe analyses indicate that dissolution of coccoliths and foraminifera in limestones are the principal sources of cementation. The similar composition of cements in sandstones, fractures and injection features suggests a common formation. Burial history modelling shows cement precipitation is synchronous with periods of excess pressure and therefore excess pressure release associated with rock failure is proposed as a prominent mechanism for initiating cementation.
Time-of-flight neutron diffraction studies of clay-fluid interactions under basin conditions
Authors: Skipper N. T. , Williams G. D. , de Siqueira A. V. C. , Lobban C. , Soper A. K.
Published: July 2002

Neutron diffraction experiments can provide an extremely high-resolution structural picture of clay-fluid systems. Here we describe the application of time-of-flight neutron scattering to hydrated clays, including discussion of issues such as isotopic labelling, sample containment, and data analysis. Recent studies of hydrated vermiculites under ambient conditions are used as an example. We then describe a new high-pressure/high-temperature sample environment that is being used to study clay-fluid interactions, in situ under hydrostatic sedimentary basin conditions. This environment enables us to approximate conditions encountered during burial, at depths of up to 10 km.
SIMS stable isotope measurement: counting statistics and analytical precision
Authors: Fitzsimons I. C. W. , Harte B. , Clark R. M.
Published: July 2002

Analytical precision is vital in the interpretation of stable isotope data collected by secondary ion mass spectrometry (SIMS) given the small analysis volumes and the small magnitude of natural isotopic variations. The observed precision of a set of measurements is represented by the standard deviation(precision of an individual measurement) or the standard error of the mean (precision of the mean value). The SIMS data show both systematic variations with time and random Poisson variability, but the former largely cancel out when data for two different isotopes are expressed as a ratio. The precision of a SIMS isotope ratio routinely matches that predicted by Poisson counting statistics and can approach that of conventional bulk analysis techniques for counting times of several hours. All sample analyse must be calibrated for instrumental mass fractionation using SIMS analyses of a standard material. There is often a gradual drift in the mass fractionation with time, but this can be modelled by least-squares regression of the standard isotope ratios. Drift in the sample analyses is eliminated by using the relevant point on this regression line to calibrate each sample. The final precision of a corrected isotope ratio must take into account the scatter in both the sample and the standard data.
Effect of growth conditions on the birefringence of mixed crystals revealed in alum solid solutions
Authors: Shtukenberg A. G. , Punin Yu. O. , Soloviev V. N.
Published: July 2002

An experimental study of optical anomalies in solid solutions of alums in relation to their composition, growth temperatures and rates, and hydrodynamic regime was carried out. Theoretical analysis of the data showed that they can be understood in terms of a mechanism of kinetic ordering of the isomorphous atoms (the phenomenon of so-called ‘growth dissymmetrization’). A theoretical model is presented which is supported by data for a number of minerals and synthetic compounds, which are known for their optical anomalies due to growth dissymmetrization.
Th-rich loparite from the Khibina alkaline complex, Kola Peninsula: isomorphism and paragenesis
Authors: Mitchell Roger H. , Chakhmouradian Anton R.
Published: July 2002

Th-rich (up to 18.4 wt% ThO2) loparite occurs as an accessory phase in foyaite pegmatites at Mt. Eveslogchorr, Khibina complex, Russia. It is associated with aegirine, astrophyllite, eudialyte, lorenzenite, lamprophyllite, magnesio-arfvedsonite and gerasimovskite. Loparite crystals are zoned from niobian loparite (core) to niobian thorian and thorian niobian loparite (rim). Th-enrichment is accompanied by a decrease in Na, LREE, Sr and increase in A-site vacancies. The most Th-rich composition approaches (Na0.39LREE0.19Th0.12Ca0.05Sr0.02)Σ0.77(Ti0.76Nb0.27)Σ1.03O3. The mineral is partly or completely metamict and after annealing gives an X-ray diffraction powder pattern similar to that of synthetic NaLaTi2O6 and naturally occurring loparite of different composition. For the Th-rich rim sample, the five strongest diffraction lines (Å) are: 2.72 (100) 110, 1.575 (60) 211, 1.925 (40), 1.368 (30) 220, 1.222 (20) 310; a = 3.867(2) Å. The X-ray diffraction patterns do not exhibit peak splitting or other diffraction lines typical of low-symmetry and ordered perovskite-type structures. Composition determinations, infrared transmission spectroscopy and X-ray diffractometry show that thorian loparite is partly replaced by betafite with LREE and Th as dominant A-site cations (‘ceriobetafite’). Some loparite samples also exhibit thin replacement mantles of belyankinite with high LREE2O3 and ThO2 contents. Both ‘ceriobetafite’ and belyankinite were formed due to metasomatic alteration of loparite.