bluuebunny/crossref_metadata_2025 huggingface dataset:
Infant-mother attachment and behavior problems in healthy and chronically ill preschoolers
Authors: Goldberg Susan , Gotowiec Andrew , Simmons Robert J.
Published: March 2009

Analysis of longitudinal data for 145 children [51 healthy, 40 with cystic fibrosis (CF), and 54 with congenital heart disease (CHD)] was conducted: (a) to ascertain whether behavioral problems evident in older medically compromised children would be reported as early as 2–3 years-of-age; and (b) to test theoretical predictions concerning the role of infant-mother attachment in the etiology of behavior problems. As predicted, children with a medical diagnosis received higher scores from parents on the Child Behavior Checklist (CBCL), primarily on the Internalizing scale. Reports of somatic symptoms did not account for this effect. Contrary to predictions, children with CHD were reported to have more behavior problems than those with CF. Secure attachment was associated with lower CBCL scores for internalizing problems regardless of medical status. The increase in behavior problem reports associated with insecure attachment was shown to reflect an effect of avoidance rather than insecurity per se. The importance of distinguishing effects of different types of insecurity and the need for meta-analytic strategies to do so is emphasized.
The social problem-solving skills of anxious-withdrawn children
Authors: Stewart Shannon L. , Rubin Kenneth H.
Published: March 2009

The purpose of this investigation was to contrast the social competencies of groups of extremely withdrawn and average children. Fifty-five kindergarten, Grade 2 and Grade 4 children were observed during dyadic play in a laboratory setting. Results indicated that (a)withdrawnchildren displayed fewer social problem-solving initiations, produced fewer socially assertive strategies, and were less successful in their attempts, compared to their more sociable age-mates; (b)averagechildren experienced fewer failures in meeting their social goals with increasing age but withdrawn children did not; (c) the discrepancy in failure rates for “high cost” social goals between the two target groups increased with increasing age; and (d) withdrawn children were less likely than average children to reinitiate a social problem-solving attempt subsequent to failure.
Social and school adjustment of shy and aggressive children in China
Authors: Chen Xinyin , Rubin Kenneth H. , Li Boshu
Published: March 2009

Fifty-seven extremely shy-inhibited children, 59 extremely aggressive children, and 352 of their average counterparts, 8 and 10 years-of-age, residing in Shanghai, the People's Republic of China, were compared on sociometric nominations of peer acceptance and rejection, teachers' assessments of school related competencies, a self-report measure of depression, and Chinese measures of normative school behavior, honorship, leadership, and academic achievement. The results indicated that, as in the Western literature, aggressive children in China were more likely to have difficulties in adjustment than their average age-mates. Inconsistent with the results in Western literature, shy-inhibited children in China were found to be more accepted by peers than their average age-mates. Furthermore, compared with the average and aggressive children, shy-inhibited children were most likely to be considered for honorship and leadership positions and were regarded by teachers as the most competent in school. Finally, the three comparison groups did not differ on a measure of depression. Children in China, however, evidenced higher depression scores than a comparison group in the West. Given these findings, it seems to be important to examine, in the future, the processes of socialization that lead to social adjustment and maladjustment of shy-inhibited and aggressivedisruptive children in non-Western cultures.
Adjustment of antisocial and nonantisocial rejected adolescents
Authors: French Doran C. , Conrad Jody , Turner Tamara M.
Published: March 2009

This study was designed to expand the investigation of peer-rejected subgroup differences to adolescence. A sample of 501 eighth-grade adolescents (age 13–14 years) were assessed. These students and their classmates (1,082 15–16-year-olds) were assessed at 10th grade. Rejected-antisocial and rejected-nonantisocial subgroups were identified at both time periods using peer ratings of social status and antisocial behavior. They were compared with accepted, accepted-antisocial, and accepted-nonantisocial subgroups. Results are consistent with past research indicating significant heterogeneity within the rejected population. Rejected-antisocial adolescents exhibited elevated problem behavior (substance use and deviant peer involvement), depression, and school adjustment difficulties (low attendance, low achievement, and school discipline problems). Rejected-nonantisocial students in contrast exhibited little problem behavior, but were characterized by low physical attractiveness and lower involvement in athletics. Discussions of psychopathological risk associated with peer rejection must account for the heterogeneity and extreme differences between antisocial and nonantisocial-rejected adolescents. Comparison of antisocial and nonantisocial-rejected children with their respective antisocial and nonantisocial-accepted comparison groups revealed few differences. This calls into question the unique contribution of rejection in the development of psychopathology.
Behavior problems in 5-year-old monozygotic and dizygotic twins: Genetic and environmental influences, patterns of regulation, and internalization of control
Authors: Zahn-Waxler Carolyn , Schmitz Stephanie , Fulker David , Robinson Joann , Emde Robert
Published: March 2009

Genetic influence on externalizing problems, internalizing problems, and attentional/activity problems in 5-year-olds was consistently identified across informants and assessment contexts. Effects of the shared environment were identified as well but with less consistency (i.e., only from parents, not teachers, and more from father than mother reports). Correlations between observed patterns of regulation at ages 3, 4, and 5 years and behavior problems at age 5 years were often significant, but low in magnitude and specific to teacher reports. Adaptive internalization of control at each age (e.g., frustration tolerance, capacity to attend and focus, good impulse control) predicted fewer externalizing problems. Internalization of standards, reflected in children's moral themes, understanding of reciprocity, and constructive social problem solving, also were sometimes associated with fewer problems. Significant correlations were low in magnitude and again specific to teacher reports. Externalizing problems were more prevalent for boys than girls, and regulation (i.e., internalization of control and standards) was more characteristic of girls than boys.
Regulatory processes and the development of cognitive representations
Authors: Derryberry Douglas , Reed Marjorie A.
Published: March 2009

Although the construct of regulation is usually applied to ongoing behavior, it also has implications for ongoing cognition and the development of cognitive representations. We propose that subcortical motivational systems influence cortical representations in two general ways. First, they regulate response processes, promoting a general selection of information to which the child is exposed. Second, motivational systems regulate attention, promoting a more selective stabilization of representations for motivationally relevant sources of information. Together with the environment, these regulatory processes shape the child's developing representations. Individual differences in these processes result in cortical representational systems that enhance the motivational systems* ability to detect relevant inputs and to guide behavior in light of them. Examples are provided that focus on fearful children, discussing how their self-representation may contribute to anxious psychopathology.
Logical, analogical, and psychological reasoning in autism: A test of the Cosmides theory
Authors: Scott Fiona J. , Baron-Cohen Simon
Published: March 2009

An important regulatory process in the development of behavior is cognition. However, cognition as a blanket term is far too broad to be useful. Rather, specific types of cognition need to be examined separately. One proposal is that one type of human reasoning evolved in a social context, to solve social problems. Here, we report two experiments that use autism to test a prediction from that theory: that social intelligence should be independent of nonsocial intelligence. Autism was chosen because deficits in social reasoning (“theory of mind”) are well known. The question we tested was whether their theory of mind deficit was dissociable from abstract and relational reasoning ability. In particular, we expected that the abnormalities in the behavioral development of children with autism would be regulated by abnormalities in theory of mind reasoning rather than other forms of reasoning. Children with autism and matched controls were given tests of abstracting reasoning, which did not involve mental state understanding. Results showed that children with autism performed comparably to the control groups, both on a test of transitive inferential reasoning and on a test of analogical reasoning. These results lend support to the specificity of the theory of mind hypothesis for autism and to Cosmides' theory of the evolution of social intelligence. They also show that cognition as a regulatory process in development needs to be examined in highly specific ways.
Paternal alcohol use and the mother-infant relationship
Authors: Eiden Rina Das , Leonard Kenneth E.
Published: March 2009

The purpose of this study was to examine the association between paternal alcohol use and the mother-infant relationship. A related goal was to investigate the role of maternal depression and marital satisfaction in moderating this relationship. Subjects were 55 mother-infant dyads (12–24-month-old infants) who were observed in the Strange Situation paradigm to assess infant attachment and in structured play interactions. There were 23 families with heavy drinking fathers and 32 with light drinking fathers. As predicted, infants of heavy drinking fathers were more likely to be insecurely attached compared to infants of light drinking fathers. Contrary to expectations, neither maternal depression nor marital interaction mediated the relationship between paternal alcohol use and mother-infant interactions. However, maternal depression did interact with paternal alcohol use to predict infant attachment security and maternal sensitivity. There was also an interactive effect of marital satisfaction and paternal alcohol use on maternal sensitivity. The results suggest that paternal alcohol use may influence family functioning and the mother-child relationship as early as infancy and suggest one possible pathway toward maladjustment among infants of heavy drinking fathers. However, in addition to investigating the impact of paternal alcohol use on the father-infant relationship, the influence of various familial factors associated with paternal alcohol use need to be more closely examined from a longitudinal perspective.
The developmental pathways to schizophrenia: Potential moderating effects of stress
Authors: Walker Elaine F. , Neumann Craig C. , Baum Kym , Davis Dana M. , Diforio Donald , Bergman Andrea
Published: March 2009

The observations of family members as well as the results of past research suggest that a variety of developmental pathways can precede the onset of schizophrenia in early adulthood. In this article, we describe recent findings from our research on the childhood precursors of schizophrenia. Taken together, the results indicate that childhood behavioral, emotional, and motoric dysfunction occur at a higher rate in preschizophrenia subjects when compared to control subjects. Further, there are developmental changes as well as significant variability among schizophrenia patients in the nature and severity of childhood impairment. Drawing on the prevailing diathesis-stress model, we explore the moderating role that stress exposure and reactivity may play in the expression of the organic diathesis for schizophrenia. Specifically, we consider the role of the biological stress response in the production of developmental changes and individual differences in the pathways to schizophrenia. Given extant models of dopamine involvement in the neuropathology of schizophrenia, stress-induced Cortisol release may alter the expression of subcortical abnormalities in dopamine neurotransmission. Thus, we present a neural mechanism for the hypothesized behavioral sensitivity to stress exposure in schizophrenia, and explore the capacity of the model to account for the changing behavioral manifestations of vulnerability.
Finality in the eye of the beholder: Multiple sources, multiple time points, multiple paths
Authors: Feiring Candice , Lewis Michael
Published: March 2009

This study explores the coherence between different raters of adolescent psychopathology and examines the coherence of these ratings with earlier and later events associated with the development of psychopathology. In particular, teachers', mothers', and adolescents' ratings of the 13-year-old adolescents are examined. Additionally, the earlier factors of attachment status, environmental stress, and the friendship network are related to the different ratings. Both earlier factors and rater judgments are used to examine subsequent use of psychotherapy. The results show little coherence between raters on the presence of psychopathology in 13-year-olds and little coherence between earlier events and subsequent raters' judgments of psychopathology. However, earlier stress events and teachers' ratings of 13-year-olds' psychopathology are related to subsequent therapy use.
The genetic etiology of childhood depressive symptoms: A developmental perspective
Authors: Thapar Anita , McGuffin Peter
Published: March 2009

Although there is some evidence to suggest that depressive symptoms show age-related changes, it remains uncertain as to whether there are also developmental variations in the etiology of depression. In this article, we present findings from a population-based study of twins aged 8 to 16 years with the aim of examining the genetic etiology of depressive symptoms and the effects of age. The results suggest that environmental factors influence the transmission of depressive symptoms in childhood. However depressive symptoms in adolescence appear to be highly heritable. The etiology of depressive symptoms was further explored using factor-derived scores that again suggested the importance of genetic factors in adolescence. However there was some suggestion that genetic influences may contribute to certain types of symptoms (self-deprecation/self-esteem) even in childhood.
Genetically informative designs for distinguishing developmental pathways during adolescence: Responsible and antisocial behavior
Authors: Neiderhiser Jenae M. , Reiss David , Hetherington E. Mavis
Published: March 2009

During the transition from early to middle adolescence there are numerous changes internal to the adolescent, such as the onset of puberty and changes in cognitive functioning, and external to the adolescent in terms of social reactions to the adolescent and changes in expectations. These changes may also be explained in terms of genetic and environmental influences on change and stability. This study employs the longitudinal sample from both waves of the Nonshared Environment in Adolescent Development (NEAD) project (395 families). The NEAD project includes adolescent siblings residing in never-divorced families (MZ and DZ twins and full siblings) and in stepfamilies (full, half, and unrelated siblings). The sample was assessed on two measurement occasions, 3 years apart. On average, the first measurement occasion assessed the families during early adolescence and the second measurement occasion occurred during middle adolescence. Composite measures of parent reports, adolescent self-reports and observer ratings of three constructs of adolescent adjustment (antisocial behavior, autonomy, and social responsibility) were examined in this analysis. Each construct showed a different pattern of genetic and environmental contributions to stability and change, suggesting different developmental pathways for each domain of adolescent adjustment. For example, genetic influences were important for both change and stability in antisocial behavior. Stability in social responsibility, on the other hand, was influenced by primarily genetic factors, while nonshared environmental factors were predominantly responsible for change. Finally, genetic and shared environmental influences contributed nearly equally to stability and change in autonomous functioning. These findings emphasize the importance of considering genetic as well as environmental factors when change in development is examined. Additionally, these data provide an armature for a comprehensive developmental theory for each of these domains of adolescent adjustment.
Autonomy and relatedness in adolescent-family interactions as predictors of young adults' states of mind regarding attachment
Authors: Allen Joseph P. , Hauser Stuart T.
Published: March 2009

This study examined the extent to which the diverging pathways taken by adolescents and their parents in establishing autonomy and relatedness in their interactions at age 14 served as stage-specific markers of underlying attachment processes that could help predict states of mind regarding attachment of the adolescents 11 years later as young adults. Adolescents in two-parent families (N=73) and their parents, originally selected from either a high school sample or a psychiatrically hospitalized sample, participated in a revealed differences family interaction task when adolescents were 14 years of age. At age 25, subjects were reinterviewed using the Adult Attachment Interview, which yielded ratings of specific states of mind and overall organization of models of attachment relationships. After accounting for the prior psychiatric history of the sample (which was highly related to attachment insecurity) and global indices of functioning in both adolescence and young adulthood, coherence/ security in adults' states of mind regarding attachment was predicted from maternal behaviors promoting adolescent autonomy and relatedness 11 years earlier. One indicator of adult preoccupation with attachment relationships, passivity of thought processes, was predicted from adolescents' autonomy-inhibiting behaviors, specifically from the presence of enmeshing behaviors and the absence of distancing behaviors. Results are interpreted as suggesting that establishing autonomy and relatedness with parents may be an attachment-related, developmental task for both normal and at-risk adolescents, and that serious psychopathology and difficulties establishing autonomy and relatedness in adolescence may represent two independent pathways to insecure attachment models in young adulthood.
Step bisimulation is pomset equivalence on a parallel language without explicit internal choice
Authors: Troeger Douglas R.
Published: March 2009

We focus attention on a language ℒ generated by a set of elementary actions under operations of sequential composition, external binary choice, iteration, and non-nested disjoint parallel composition: that is, on an especially simple parallel language without explicit internal, or ‘local’, nondeterminism. ℒ is nondeterministic, despite the restriction to external choice, since a given action may occur in both subterms F and G of the parallel composition F ║ G. We exhibit a single set of equations that axiomatizes both step bisimulation and pomset equivalence on ℒ Given that step bisimulation and pomset equivalence are incomparable on the language ℒ+ obtained from ℒ by relaxing just the constraint on choice, the coincidence of these equivalences on ℒ suggests that the elimination of explicit internal choice can result in simplifications at the semantic level. We reinforce this impression by showing for ℒ that step bisimulation (i) coincides with pomset bisimulation equivalence, (ii) is real-time consistent, and (iii) has step trees as concrete representatives of its equivalence classes. Moreover, we show that none of these results holds for the language ℒ+ Finally, step trace equivalence is proved not to coincide with step bisimulation equivalence on ℒ.
Universal domains and the amalgamation property
Authors: Droste Manfred , Gübel Rüdiger
Published: March 2009

In the theory of denotational semantics of programming languages, several authors have constructed various kinds of universal domains. We present here a categorical generalization of a well-known result in model theory, which we use to characterize large classes of reasonable categories that contain universal homogeneous objects. The existence of such objects is characterized by the condition that the finite objects in the category satisfy the amalgamation property. We derive from this the existence and uniqueness of universal homogeneous domains for several categories of bifinite domains, with embedding-projection-pairs as morphisms. We also obtain universal homogeneous objects for various categories of stable bifinite domains. In contrast, several categories of event domains and concrete domains and the category of all coherent Scott-domains do not contain universal homogeneous objects. Finally, we show that all our constructions can be performed effectively.
Hypercoherences: a strongly stable model of linear logic
Authors: Ehrhard Thomas
Published: March 2009

We present a new model of classical linear logic based on the notion of strong stability that was introduced recently in a work about sequentiality written jointly with Antonio Bucciarelli.
Demonic operators and monotype factors
Authors: Backhouse Roland , van der Woude Jaap
Published: March 2009

This paper tackles the problem of constructing a compact, point-free proof of the associativity of demonic composition of binary relations and its distributivity through demonic choice. In order to achieve this goal, a definition of demonic composition is proposed in which angelic composition is restricted by means of a so-called ‘monotype factor’. Monotype factors are characterised by a Galois connection similar to the Galois connection between composition and factorisation of binary relations. The identification of such a connection is argued to be highly conducive to the desired compactness of calculation.
Categories, relations and dynamic programming
Authors: Moor Oege De
Published: March 2009

Dynamic programming is a strategy for solving optimisation problems. In this paper, we show how many problems that may be solved by dynamic programming are instances of the same abstract specification. This specification is phrased using the calculus of relations offered by topos theory. The main theorem underlying dynamic programming can then be proved by straightforward equational reasoning.

The generic specification of dynamic programming makes use of higher-order operators on relations, akin to the fold operators found in functional programming languages. In the present context, a data type is modelled as an initial F-algebra, where F is an endofunctor on the topos under consideration. The mediating arrows from this initial F-algebra to other F-algebras are instances of fold – but only for total functions. For a regular category ε, it is possible to construct a category of relations Rel(ε). When a functor between regular categories is a so-called relator, it can be extended (in some canonical way) to a functor between the corresponding categories of relations. Applied to an endofunctor on a topos, this process of extending functors preserves initial algebras, and hence fold can be generalised from functions to relations.

It is well-known that the use of dynamic programming is governed by the principle of optimality. Roughly, the principle of optimality says that an optimal solution is composed of optimal solutions to subproblems. In a first attempt, we formalise the principle of optimality as a distributivity condition. This distributivity condition is elegant, but difficult to check in practice. The difficulty arises because we consider minimum elements with respect to a preorder, and therefore minimum elements are not unique. Assuming that we are working in a Boolean topos, it can be proved that monotonicity implies distributivity, and this monotonicity condition is easy to verify in practice.
A universality theorem for PCF with recursive types, parallel-or and ∃
Authors: Streicher Thomas
Published: March 2009

In a PCF-like call-by-name typed λ-calculus with a minimal fixpoint operator, ‘parallelor’, Plotkin's ‘continuous existential quantifier’ ∃ and recursive types together with constructors and destructors, all computable objects can be denoted by terms of the programming language. According to A. Meyer's terminology (cf. Meyer (1988)), such a programming language is called universal in the sense that any extension of it must be conservative, as all computable objects can already be expressed by program terms.

As a byproduct, we get that, in principle, recursive types could be totally avoided, as they appear as syntactically expressible retracts of the non-recursive type → , where and are the flat domains of natural numbers and boolean values, respectively.
Partial hyperdoctrines: categorical models for partial function logic and Hoare logic
Authors: Knijnenburg Peter , Nordemann Frank
Published: March 2009

In this paper we provide a categorical interpretation of the first-order Hoare logic of a small programming language by giving a weakest precondition semantics for the language. To this end, we extend the well-known notion of a (first-order) hyperdoctrine to include partial maps. The most important new aspect of the resulting partial (first-order) hyperdoctrine is a different notion of morphism between the fibres. We also use this partial hyperdoctrine to give a model for Beeson's Partial Function Logic such that (a version of) his axiomatization is complete with respect to this model. This shows the usefulness of the notion, independent of its intended use as a model for Hoare logic.
Sketches and computation – II: dynamic evaluation and applications
Authors: Duval Dominique , Reynaud Jean-Claude
Published: March 2009

In the first part of this paper (Duval and Reynaud 1994), we defined a categorical framework, based on the notion of sketch, for specification and evaluation in the senses of algebraic specifications and algebraic programming. Static evaluation in quasi-projective sketches was defined in Part I; in this paper, dynamic evaluation is introduced. It deals with more general structures, which may have no initial model. Until now, this process has not been used in algebraic specification systems, but computer algebra systems are beginning to use it as a basic tool. Finally, we give some applications of dynamic evaluation to computation in field extensions.
An Oxford survey of order sorted algebra
Authors: Goguen Joseph , Diaconescu Răzvan
Published: March 2009

This paper surveys several different variants of order sorted algebra (abbreviatedOSA), comparing some of the main approaches (overloaded OSA, universe OSA, unified algebra, term declaration algebra,etc.), emphasising motivation and intuitions, and pointing out features that distinguish the original ‘overloaded’ OSA approach from some later developments. These features include sort constraints and retracts; the latter is particularly useful for handling multiple data representations (including automatic coercions among them). Many examples are given, for most of which, runs are shown on the OBJ3 system.

This paper also significantly generalises overloaded OSA by dropping the regularity and monotonicity assumptions, and by adding signatures of non-monotonicities, which support simple semantics for some aspects of object oriented programming. A number of new results for this generalisation are proved, including initiality, variety, and quasi-variety theorems. Axiomatisability results àlaBirkhoff are also proved for unified algebras.
Categorical concepts for parameterized partial specifications
Authors: Claßen Ingo , GroßE-Rhode Martin , Wolter Uwe
Published: March 2009

Categorical constructions inherent to a theory of algebras with strict partial operations are presented and exploited to provide a categorical deduction calculus for conditional existence equations and an alternative definition of such algebras based on the notion of syntactic categories. A compact presentation of the structural theory of parameterized (partial) specifications is given using the categorical approach. This theory is shown to be suitable for providing initial semantics as well as the compositionality results necessary for the definition of specification languages likeACT ONEandACT TWO
Algebraic high-level net transformation systems
Authors: Padberg Julia , Ehrig Hartmut , Ribeiro Leila
Published: March 2009

The concept of algebraic high-level net transformation systems combines two important lines of research recently introduced in the literature:algebraic high-level nets(AHL-nets for short) andhigh-level replacement systems(HLR-systems for short). In both cases a categorical formulation of the corresponding theory has turned out to be highly important and is also a good basis for the integration of these concepts in this paper.

AHL-nets combine Petri nets with algebraic specifications and provide a powerful specification technique for distributed systems including data types and processes.

HLR-systems are transformation systems for high-level structures such as graphs, hypergraphs, algebraic specifications and different kinds of Petri nets. The theory of HLRsystems - formulated already in a categorical framework - is applied in this paper to AHLnets. Thus we obtain AHL-net transformation systems as an instantiation of HLR-systems to AHL-nets. This allows us to build up AHL-nets from basic components and to transform the net structure using rules or productions in the sense of graph grammars. This concept is illustrated by extending the well-known example of ‘dining philosophers’. We are able to show that AHL-net-transformation systems satisfy several important compatibility properties. On the one hand we obtain a local Church-Rosser and Parallelism Theorem, which is well-known for graph grammars and has recently been generalized to HLR-systems. This allows us to analyse concurrency in AHL-nets not only on the token level but also on the level of transformations of the net structure. On the other hand, we consider the ‘fusion’ and ‘union’ constructions for high-level structures, motivated by corresponding concepts for high-level Petri nets in the literature, and we show compatibility of these constructions with derivations of HLR-systems in general and AHL-nettransformations in particular. This means compatibility of vertical and horizontal structuring in terms of software development.
Causal dependencies in multiplicative linear logic with MIX
Authors: Asperti Andrea
Published: March 2009

A new correctness criterion for discriminating Proof Nets among Proof Structures of Multiplicative Linear Logic with the MIX rule is provided. This criterion is inspired by an original interpretation of Proof Structures as distributed systems, and logical formulae as processes. The computation inside a system corresponds to the logical flow of information inside a proof, that is, roughly speaking, a distributed version of Girard's token trip. Proof Nets are then characterised as deadlock free Proof Structures (deadlock free distributed systems). This result follows by explicitly considering the causal dependencies among logical formulae inside proofs, and it provides a new understanding of notions such as acyclicity, chains and empires in terms of concurrent computations.
A generalization of the trie data structure
Authors: Connelly Richard H. , Morris F. Lockwood
Published: March 2009

Tries, a form of string-indexed look-up structure, are generalized, in a manner first discovered by Wadsworth, to permit indexing by terms built according to an arbitrary signature. The construction is parametric with respect to the type of data to be stored as values; this is essential, because the recursion that defines tries appeals from one value type to others. ‘Trie’ (for any fixed signature) is then a functor, and the corresponding look-up function is a natural isomorphism.

The trie functor is in principle definable by the ‘initial fixed point’ semantics of Smyth and Plotkin. We simplify the construction, however, by introducing the ‘category-cpo’, a class of category within which calculations can retain some domain-theoretic flavor. Our construction of tries extends easily to many-sorted signatures.
A note on the structure of bilattices
Authors: Avron A.
Published: March 2009

A notion ofbilatticewas first proposed by Ginsberg as a general framework for many applications. Related notions were further investigated and applied for various goals by Fitting. In the present paper a general definition of bilattices is proposed, which covers all particular cases that have actually been used in the literature. It is shown also that in the finite case every bilattice in our sense is graphically representable by a special type of a two-dimensional diagram.
Equivalent definitions of recognizability for sets of graphs of bounded tree-width
Authors: Courcelle Bruno , Lagergren Jens
Published: March 2009

We show that a set of finite graphs of tree-width at most k is recognizable (with respect to the algebra of graphs with an unbounded number of sources) if and only if it is recognizable with respect to the algebra of graphs of tree-width at most k with at most k sources.
The structure of interlaced bilattices
Authors: Avron A.
Published: March 2009

Bilattices were introduced and applied by Ginsberg and Fitting for a diversity of applications, such as truth maintenance systems, default inferences and logic programming. In this paper we investigate the structure and properties of a particularly important class of bilattices called interlaced bilattices, which were introduced by Fitting. The main results are that every interlaced bilattice is isomorphic to the Ginsberg-Fitting product of two bounded lattices and that the variety of interlaced bilattices is equivalent to the variety of bounded lattices with two distinguishable distributive elements, which are complements of each other. This implies that interlaced bilattices can be characterized using a finite set of equations. Our results generalize to interlaced bilattices some results of Ginsberg, Fitting and Jónsson for distributive bilattices.
! and ? – Storage as tensorial strength
Authors: Blute R. F. , Cockett J. R. B. , Seely R. A. G.
Published: March 2009

We continue our study of the negation-free structure of multiplicative linear logic, as represented by the structure of weakly distributive categories, to consider the ‘exponentials’! and ? in the weakly distributive context. In addition to the usual triple and cotriple structure that one would expect on each of the two operators, there must be some connection between them to replace the de Morgan relationship found in the linear logic context. This turns out to be the notion of tensorial strength. We analyze coherence for this situation, using a modification of the usual nets due to Danos, which is a form suitable for linear logic with exponentials but without negation.
Connected limits, familial representability and Artin glueing
Authors: Carboni Aurelio , Johnstone Peter
Published: March 2009

We consider the following two properties of a functor F from a presheaf topos to the category of sets: (a) F preserves connected limits, and (b) the Artin glueing of F is again a presheaf topos. We show that these two properties are in fact equivalent. In the process, we develop a general technique for associating categorical properties of a category obtained by Artin glueing with preservation properties of the functor along which the glueing takes place. We also give a syntactic characterization of those monads on Set whose functor parts have the above properties, and whose units and multiplications are cartesian natural transformations.
Church-Rooser property and homology of monoids
Authors: Lafont Yves , Prouté Alain
Published: March 2009

We present a result of C.C. Squier relating two topics:

— the canonical rewriting systems, which have been widely studied by computer scientists as a tool for solving word problems,

— the homology of groups (more generally of monoids), which belongs to the core of pure mathematics, on the borders of algebra and topology.
Semantics of the second order lambda calculus
Authors: Jacobs Bart
Published: March 2009

In the literature ther are two main notins of model for the second order λ-calculus: one by Bruce, Meyer and Mitchell (the BMM-model, for short) in set-theoretical formulation and one category-theoretical by Seely. Here we generalise Seely's notion, using semifunctors and semi-adjunctions from Hayashi, and introduce λ2-algebras, λη2-algebras, λ2-models and λη-models, similarly to the untyped λ-calculus. Non-extensional abstraction of both term and type variables is described by semi-adjunctions (essentially as in Martini's thesis). We show that also for second order sume, the β-(and commutation!) conversions correspond to semi-functoriality and that the (additional) η-conversion corresponds to ordinary fuctioriality.

In the above framework various examples – well known ones and variations – are described. Also, we determine the place of the BMM-models; an earlier version of the latter has been reported by Jacobs.
Engeler's scientific work
Authors: Specker E.
Published: March 2009

Erwin Engeler was born in Schaffhausen on 13 February 1930 a citizen of Wagenhausen (Thurgovia). He attended school in Diessenhofen (TG) and Schaffhausen and looks back on his various schools warmly as having provided a conducive environment. His schoolwork also left him time for other activities. For one, he pursued a career as a boy scout which he crowned by attaining the position of Rover Commissary of all Thurgovia. For another, he was an avid client of the municipal library of Schaffhausen. One book which he found there was Hilbert-Bernays' ‘Grundlagen der Mathematik’. One wonders what Erwin would have said if a soothsayer had told him that the author's own copy would one day be passed on to him by the late Bernays' family.
Functions as processes
Authors: Milner Robin
Published: March 2009

This paper exhibits accurate encodings of the λ-calculus in the π-calculus. The former is canonical for calculation with functions, while the latter is a recent step (Milner et al. 1989) towards a canonical treatment of concurrent processes. With quite simple encodings, two λ-calculus reduction strategies are simulated very closely; each reduction in λ-calculus is mimicked by a short sequence of reductions in π-calculus. Abramsky's precongruence of applicative bisimulation (Abramsky 1989) over λ-calculus is compared with that induced by the encoding of the lazy λ-calculus into π-calculus; a similar comparison is made for call-by-value λ-calculus.
A new approach to abstract data types, I Informal development
Authors: Feferman Solomon
Published: March 2009

The concept of abstract data types (ADTs) has emerged in the last fifteen years or so as one of the major programming design tools, with the emphasis on modular construction of large-scale programe. ADTs provide the means for seperating how data objects may be used from the different ways in which they actually are, or might be, implemented. A foundation for the theory of compputation with ADTs must provide answers to such questions as: What are ADTs and how may they be specified? What does it mean to implement an ADT? How may we construct new ADTs from old ones? What does it mean to compute with ADTs? This paper is devoted to a new and rather general, constructively based approach to these questions.
Building domains from graph models
Authors: Phoa Wesley
Published: March 2009

In this paper we study partial equivalence relations (PERs) over graph models of the λcalculus. We define categories of PERs that behave like predomains, and like domains. These categories are small and complete; so we can solve domain equations and construct polymorphic types inside them. Upper, lower and convex powerdomain constructions are also available, as well as interpretations of subtyping and bounded quantification. Rather than performing explicit calculations with PERs, we work inside the appropriate realizability topos: this is a model of constructive set theory in which PERs, can be regarded simply as special kinds of sets. In this framework, most of the definitions and proofs become quite smple and attractives. They illustrative some general technicques in ‘synthetic domain theory’ that rely heavily on category theory; using these methods, we can obtain quite powerful results about classes of PERs, even when we know very little about their internal structure.
Projections for polymorphic first-order strictness analysis
Authors: Hughes John , Launchbury John
Published: March 2009

We apply the categorical properties of polymorphic functions to compile-time analysis, specifically projection-based strictness analysis. First we interpret parameterised types as functors in a suitable category, and show that they preserve monics and epics. Then we define “strong” and “weak” polymorphism, the latter admitting certain projections that are not polymorphic in the usual sense. We prove that, under the right conditions, a weakly polymorphic function is characterised by a single instance. It follows that the strictness analysis of one simple instance of a polymorphic function yields results that apply to all. We show how this theory may be applied. In comparison with earlier polymorphic strictness analysis methods, ours can apply polymorphic information to a particular instance very simply. The categorical approach simplifies our proofs, enabling them to be carried out at a higher level, and making them independent of the precise form of the programming language to be analysed. The major limitation of our results is that they apply only to first-order functions.
Helicobacter pyloriis not associated with anaemia in Latin America: results from Argentina, Brazil, Bolivia, Cuba, Mexico and Venezuela
Authors: Santos Ina S , Boccio Jose , Davidsson Lena , Hernandez-Triana Manuel , Huanca-Sardinas Elizabeth , Janjetic Mariana , Moya-Camarena Silvia Y , Paez-Valery Maria C , Ruiz-Alvarez Vladimir , Valencia Mauro E , Valle Neiva CJ , Vargas-Pinto Greta , Solano Liseti , Thomas Julian
Published: March 2009

Objective

To investigate the association betweenHelicobacter pyloriinfection and anaemia.

Design

Six cross-sectional studies.H. pyloriinfection was assessed by the [13C]urea breath test using MS or IR analysis. Hb was measured for all countries. Ferritin and transferrin receptors were measured for Argentina, Bolivia, Mexico, and Venezuela.

Setting

Health services in Argentina, Brazil and Mexico or public schools in Bolivia, Cuba and Venezuela.

Subjects

In Argentina, 307 children aged 4–17 years referred to a gastroenterology unit; in Bolivia, 424 randomly selected schoolchildren aged 5–8 years; in Brazil, 1007 adults (157 men, 850 women) aged 18–45 years attending thirty-one primary health-care units; in Cuba, 996 randomly selected schoolchildren aged 6–14 years; in Mexico, seventy-one pregnant women in their first trimester attending public health clinics; in Venezuela, 418 children aged 4–13 years attending public schools.

Results

The lowest prevalence ofH. pylorifound was among children in Argentina (25·1 %) and the highest in Bolivia (74·0 %). In Bolivia, Cuba and Venezuela children showed similar prevalence ofH. pyloriinfection as in Brazilian and Mexican adults (range 47·5 % to 81·8 %). Overall anaemia prevalence was 11·3 % in Argentina, 15·4 % in Bolivia, 20·6 % in Brazil, 10·5 % in Cuba and 8·9 % in Venezuela. Adjusted analyses allowing for confounding variables showed no association betweenH. pyloricolonization and anaemia in any study. Hb, ferritin and transferrin receptor levels were also not associated withH. pyloriinfection in any country.

Conclusions

The present study showed no evidence to support the hypothesis thatH. pyloricontributes to anaemia in children, adolescents, adults or pregnant women in six Latin American countries.
Nitrate isotope anomalies reflect N2 fixation in the Azores Front region (subtropical NE Atlantic)
Authors: Bourbonnais Annie , Lehmann Moritz F. , Waniek Joanna J. , Schulz‐Bull Detlef E.
Published: March 2009

The subtropical northeast Atlantic has previously been identified as a marine environment with an apparent imbalance between low nitrate supply to the surface and concurrent high export production. To better constrain the sources and fluxes of mixed layer nitrate and to assess the potential role of N2 fixation in providing new nitrogen (N), we investigated the depth distribution of nitrate δ15N and δ18O at six stations across the Azores Front in the NE Atlantic. In addition, we measured the δ15N of dissolved organic N (DON) in surface waters and of sinking particulate N collected in sediment traps at 2000 m depth between 2003 and 2005 at Station KIEL276. The nitrate isotope profiles at the majority of the hydrographic stations displayed a decrease in the δ15N from depth toward low‐nitrate surface waters, concomitant with an increase in δ18O. Given that nitrate uptake by phytoplankton leads to a proportional increase in nitrate δ15N and δ18O, the observed surface water nitrate isotope anomalies (Δ(15;18) up to −6‰) indicate that nitrate assimilation is not the sole process controlling the isotopic composition of nitrate in the photic zone and implicate a significant addition of newly fixed N that is remineralized in surface and subsurface waters. Both the concentration of DON and its δ15N in surface water were spatially invariant, showing mean values of 4.7 ± 0.5 μmol L−1 and 2.6 ± 0.4‰ (n = 35), respectively, supporting the conjecture of a mostly recalcitrant DON pool. The weighted biannual mean δ15N of sinking particulate N (1.8 ± 0.8‰, n = 33) was low with respect to thermocline nitrate. The anomalous dual nitrate isotope signatures together with the low δ15N of export production and elevated nitrate‐to‐phosphate ratios in surface and subsurface waters strongly suggest that N2 fixation represents a substantive source of N in this part of the subtropical northeast Atlantic. Simple isotope mass balance suggests that, locally, N2 fixation supplies between 56 and 259 mmol N m−2 a−1 for phytoplankton growth in the photic zone, accounting for up to ∼40% of the estimated export production.