bluuebunny/crossref_metadata_2025 huggingface dataset:
Early behavior problems: Pathways to mental disorders in adolescence
Authors: Egeland Byron , Pianta Robert , Ogawa John
Published: March 2009

From teachers' rating in kindergarten through third grade, mutually exclusive groups of internalized, externalized, and mixed behavior problems were examined as pathways to three groups of psychiatric diagnosis in later adolescence: depression/anxiety, conduct/oppositional defiant, and other disorders. In looking both forward and backwards, the relation between behavior problems in the early school years, regardless of type, and psychopathology in adolescence, regardless of diagnosis, was very strong. The relations between type of early problems and specific outcomes were weak. The findings provided support for both the constructs of multifinality and equifinality; however the nature of the pathways differed somewhat by disorder. There was a substantial amount of multifinality (dispersion of outcomes) for the early internalizing pathway. There was less multifinality for the externalizing pathway, in that there was greater correspondence between early externalizing and later antisocial outcomes than for the internalizing pathway and depressed/anxious outcomes.
Multiple pathways to self-reported depression and psychological adjustment among adolescents
Authors: Harter Susan , Whitesell Nancy R.
Published: March 2009

This study built upon earlier work documenting a theoretically derived model of four antecedents of depression, defined by a composite of global self-worth, affect (cheerful to depressed, and hope (hopefulness or hopelessness), among normative samples of adolescents. The four antecedents were: (a) perceived competence/adequacy in peer-salient domains (perceived appearance, peer likability, and athletic competence); (b) peer support; (c) perceived competence/adequacy in parent-salient domains (scholastic competence and behavioral conduct); and (d) parent support. However, not all components are observed in the profiles of individual adolescents. Thus, in this study, we examined the multiple pathways among those reporting depressive reactions (defined by the composite) as well as the different routes to positive adjustment, among those with high scores on the composite. Six profiles were identified among each group. For those reporting depressive reactions, perceived deficiencies in both peer- and parent-salient domains were particularly critical predictors. In contrast, for those reporting positive adjustment, peer and parent support were central components. The discussion emphasized the need to consider individual profile differences in planning interventions for adolescents at risk.
Other evidence for at least two alcoholisms II: Life course variation in antisociality and heterogeneity of alcoholic outcome
Authors: Zucker Robert A. , Ellis Deborah A. , Fitzgerald Hiram E. , Bingham C. Raymond , Sanford Keith
Published: March 2009

Within the framework of a cumulation/nesting theory for the emergence of adult psychopathology, a typing structure for alcoholism based upon variations in life course continuity of antisocial behavior over childhood and adulthood was examined for its ability to differentiate symptomatic and life history variations among alcoholic and nonalcoholic men accessed by way of a population-based recruitment strategy. Results supported the theory and identified two alcoholic types, one high on lifetime antisociality (antisocial alcoholic = AAL), the other low (nonantisocial alcoholic = NAAL), and a third nonalcoholic type with low lifetime antisociality. Types differed in age of onset, severity, number, and life course of alcohol problems, measures of social adaptation, amount and severity of other psychopathology, and salience of family history load of alcoholism. Antisociality and alcoholism tended to be nested characteristics.
Operations on records
Authors: Cardelli Luca , Mitchell John C.
Published: March 2009

We define a simple collection of operations for creating and manipulating record structures, where records are intended as finite associations of values to labels. A second-order type system over these operations supports both subtyping and polymorphism. We provide typechecking algorithms and limited semantic models.

Our approach unifies and extends previous notions of records, bounded quantification, record extension, and parametrization by row-variables. The general aim is to provide foundations for concepts found in object-oriented languages, within a framework based on typed lambda-calculus.
A categorical manifesto
Authors: Goguen Joseph A.
Published: March 2009

This paper tries to explain why and how category theory is useful in computing science, by giving guidelines for applying seven basic categorical concepts: category, functor, natural transformation, limit, adjoint, colimit and comma category. Some examples, intuition, and references are given for each concept, but completeness is not attempted. Some additional categorical concepts and some suggestions for further research are also mentioned. The paper concludes with some philosophical discussion.
From Petri nets to linear logic
Authors: Martí-Oliet Narciso , Meseguer José
Published: March 2009

Linear logic has recently been introduced by Girard as a logic of actions that seems well suited for concurrent computation. In this paper, we establish a systematic correspondence between Petri nets, linear logic theories, and linear categories. Such a correspondence sheds new light on the relationships between linear logic and concurrency, and on how both areas are related to category theory. Categories are here viewed as concurrent systems the objects of which are states, and the morphisms of which are transitions. This is an instance of the Lambek-Lawvere correspondence between logic and category theory that cannot be expressed within the more restricted framework of the Curry-Howard correspondence.
Admissible and derivable rules in intuitionistic logic
Authors: Rozière Paul
Published: March 2009

This paper gives some sufficient conditions for admissible rules to be derivable in intuitionistic propositional calculus. For example, if the premises are Harrop formulas, the rule is admissible only if it is derivable.

In deriving the results, a particular class of substitutes is introduced, which are also useful when dealing with other questions of admissibility.
Least fixpoints of endofunctors of cartesian closed categories
Authors: Lambek J.
Published: March 2009

Least fixpoints are constructed for finite coproducts of definable endofunctors of Cartesian closed categories that have weak polynomial products and joint equalizers of arbitrary families of pairs of parallel arrows. Both conditions hold in PER, the category whose objects are partial equivalence relations on N, and whose arrows are partial recursive functions. Weak polynomial products exist in any cartesian closed category with a finite number of objects as well as in any model of second order polymorphic lambda calculus: that is, in the proof theory of any second order positive intuitionistic propositional calculus, but such a category need not have equalizers. However, any finite coproduct of definable endofunctors of a cartesian closed category with weak polynomial products will have a least fixpoint in a larger category with equalizers whose objects are right ideals (or sieves) of modulo certain congruence relations, and whose arrows are induced from .
Introduction to distributive categories
Authors: Cockett J. R. B.
Published: March 2009

Distributive category theory is the study of categories with two monoidal structures, one of which “distributes” over the other in some manner. When these are the product and coproduct, this distribution is taken to be the law

which asserts that the obvious canonical map has an inverse. A distributive category is here taken to mean a category with finite products and binary coproducts such that this law is satisfied.

In any distributive category the coproduct of the final object with itself, 1 + 1, forms a boolean algebra. Thus, maps into 1 + 1 provide a boolean logic: if each such map recognizes a unique subobject, the category is a recognizable distributive category. If, furthermore, the category is such that these recognizers classify detachable subobjects (coproduct embeddings), it is an extensive distributive category.

Extensive distributive categories can be approached in various ways. For example, recognizable distributive categories, in which coproducts are disjoint or all preinitials are isomorphic, are extensive. Also, a category X having finite products and binary coproducts satisfying the slice equation (due to Schanuel and Lawvere) is extensive. This paper describes a series of embedding theorems. Any distributive category has a full faithful embedding into a recognizable distributive category. Any recognizable distributive category can be "solidified" faithfully to produce an extensive distributive category. Any extensive distributive category can be embedded into a topos.

A peculiar source of extensive distributive categories is the coproduct completion of categories with familial finite products. In particular, this includes the coproduct completion of cartesian categories, which is serendipitously, therefore, also the distributive completion. Familial distributive categories can be characterized as distributive categories for which every object has a finite decomposition into indecomposables.
Categorical data types in parametric polymorphism
Authors: Hasegawa Ryu
Published: March 2009

The categorical data types in models of second order lambda calculus are studied. We prove that Reynolds parametricity is a sufficient and necessary condition for the categorical data types to fulfill the universal properties.
A categorical approach to database semantics
Authors: Baclawski Kenneth , Simovici Dan , White William
Published: March 2009

We propose a formalization of standard database management systems using topos theory. In this treatment, all constructions take place within an ambient topos, which thereby serves as the ‘universe of discourse’. A database schema is defined using objects and morphisms in the ambient topos. A database state for a given schema involves not only the ambient topos but also an internal category within the topos. This approach neatly separates the schema from the state data by placing them in distinct category structures. It is shown that database states can either be regarded syntactically as objects in an external topos or semantically as morphisms in an internal slice category. A number of operations are introduced that correspond to operations used in standard database systems. Extraction selects some of the tables, attributes and domains of a database state. The squeeze operation performs an ‘elimination of duplicates’, which can be combined with extraction to obtain an operation called ‘projection’ in standard relational database systems. A join operation is defined, which generalizes the relational join operation and can be used for the cartesian product and selection operations. Finally, ‘boolean’ operations of intersection, union and difference are introduced and related to the other operations.
Languages under concatenation and shuffling
Authors: Tschantz Steven T.
Published: March 2009

The shuffle product of two words u and v, denoted u‖v, is the set of all words of the form x1y1x2y2…xnyn for some n and for some (possible empty) words x1, …xn, y1, …yn, such that u = x1x2…xn, and v = y1y2…yn. In other words, u‖v is the set of all possible words that can be obtained by merging u and v so that the letters of u and v separately maintain their original orders but are allowed to alternate arbitrarily. The shuffle product of languages L and M, denoted L‖M, is the union of all u‖v for u ∈ L and v ∈ M.
Completeness of category-based equational deduction
Authors: Diaconescu Răzvan
Published: March 2009

Equational deduction is generalised within a category-based abstract model theory framework, and proved complete under a hypothesis of quantifier projectivity, using a semantic treatment that regards quantifiers as models rather than variables, and valuations as model morphisms rather than functions. Applications include many- and order-sorted (conditional) equational logics, Horn clause logic, equational deduction modulo a theory, constraint logics, and more, as well as any possible combination among them. In the cases of equational deduction modulo a theory and of constraint logic the completeness result is new. One important consequence is an abstract version of Herbrand's Theorem, which provides an abstract model theoretic foundation for equational and constraint logic programming.
An approach to object semantics based on terminal co-algebras
Authors: Reichel Horst
Published: March 2009

The categorical dual construction of initial abstract data types is studied. The resulting terminal co-algebras represent not only an implementation independent semantics of infinite objects such as streams, but also a suitable formal basis for object types in the sense of the object-oriented programming paradigm. Instances of object types may be interpreted as abstract automata with several state transition functions representing the methods of an object, and several output functions representing the attributes. By structuring the index set of the possibly infinite family of methods, and by structuring the output set, one can specify specific object types. For dealing simultaneously with complex data types and object types, it is not necessary to live within a cartesian closed category. In ccc's there are standard functional constructions for object types, but object types are not necessarily a higher-order construction. A world of data types and object types may be combined with the Rewriting Logic of Meseguer to obtain a formal basis for concurrent object systems.
D-oids: a model for dynamic data-types
Authors: Astesiano Egidio , Zucca Elena
Published: March 2009

We propose a semantic framework for dynamic systems, which, in a sense, extends the well-known algebraic approach for modelling static data structures to the dynamic case. The framework is based on a new mathematical structure, called a d-oid, consisting of a set of instant structures and a set of dynamic operations. An instant structure is a static structure, e.g. an algebra; a dynamic operation is a transformation of instant structures with an associated point to point map, which allows us to keep track of the transformations of single objects and thus is called a tracking map. By an appropriate notion of morphism, the d-oids over a dynamic signature constitute a category.

It is shown that d-oids can model object systems and support an abstract notion of possibly unique object identity; moreover, for a d-oid satisfying an identity preserving condition, there exists an essentially equivalent d-oid where the elements of instant structures are just names.
Finitary sketches and finitely accessible categories
Authors: Adámek Jiří , Rosický Jiří
Published: March 2009

Every accessible category is proved to be sketchable by a sketch with finite colimits. In contrast, a finitely accessible category is presented that cannot be sketched by a finitary sketch, i.e., a sketch with finite limits and finite colimits. Also, a category sketchable by a finitary sketch is found that is not finitely accessible.
Equivalences between logics and their representing type theories
Authors: Gardner Philippa
Published: March 2009

We propose a new framework for representing logics, called LF+, which is based on the Edinburgh Logical Framework. The new framework allows us to give, apparently for the first time, general definitions that capture how well a logic has been represented. These definitions are possible because we are able to distinguish in a generic way that part of the LF+entailment corresponding to the underlying logic. This distinction does not seem to be possible with other frameworks. Using our definitions, we show that, for example, natural deduction first-order logic can be well-represented in LF+, whereas linear and relevant logics cannot. We also show that our syntactic definitions of representation have a simple formulation as indexed isomorphisms, which both confirms that our approach is a natural one and provides a link between type-theoretic and categorical approaches to frameworks.
Datatype laws without signatures
Authors: Fokkinga Maarten M.
Published: March 2009

Using the well-known categorical notion of ‘functor’, one may define the concept of datatype (algebra) without being forced to introduce a signature (that is, names and typings for the individual sorts (types) and operations involved). This has proved to be advantageous for those theory developments where one is not interested in the syntactic appearance of an algebra.

The categorical notion of ‘transformer’ developed in this paper allows the same approach to laws: without using signatures one can define the concept of law for datatypes (lawful algebras), and investigate the equational specification of datatypes in a syntax-free manner. A transformer is a special kind of functor and also a natural transformation on the level of dialgebras. Transformers are quite expressive, satisfy several closure properties, and are related to naturality and Wadler'' Theorems For Free Theorem. In fact, any colimit is an initial lawful algebra.
Non-strict don't care algebras and specifications
Authors: Astesiano Egidio , Cerioli Maura
Published: March 2009

Non-strict don't care functions, whose foremost representative is the ubiquitousif_then_else, play an essential role in computer science. As far as the semantics is concerned, they can be modelled by their totalizations with the appropriate use of elements representing undefinedness, as D. Scott has shown in his denotational approach. The situation is not so straightforward when we consider non-strict functions in the context of an algebraic framework; this point is discussed in the last section, where we explore the relationship between non-strict don't care and total algebras. The central part of this paper, after presenting the basic properties of the category of non-strict algebras, is an investigation of conditional algebraic specifications. It is shown that non-strict conditional specifications are equivalent to disjunctive specifications, and necessary and sufficient conditions for the existence of initial models are given. Since non-strict don't care specifications generalize both the total and the partial case, it is shown how the results for initiality can be obtained as specializations.
A polynomial-time algorithm for deciding bisimulation equivalence of normed Basic Parallel Processes
Authors: Hirshfeld Yoram , Jerrum Mark , Moller Faron
Published: March 2009

A polynomial-time algorithm is presented for deciding bisimulation equivalence of so-called Basic Parallel Processes: multisets of elementary processes combined by a commutative parallel-composition operator.
Reflexive objects in topological categories
Authors: Rice Michael D.
Published: March 2009

This paper presents several basic results about the non-existence of reflexive objects in cartesian closed topological categories of Hausdorff spaces. In particular, we prove that there are no non-trivial countably compact reflexive objects in the category of Hausdorff k-spaces and, more generally, that any non-trivial reflexive Tychonoff space in this category contains a closed discrete subspace corresponding to a numeral system in the sense of Wadsworth. In addition, we establish that a reflexive Tychonoff space in a cartesian-closed topological category cannot contain a non-trivial continuous image of the unit interval. Therefore, if there exists a non-trivial reflexive Tychonoff space, it does not have a nice geometric structure.
Reductions in Intuitionistic Linear Logic
Authors: Soloviev Sergei
Published: March 2009

In this work we show how some useful reductions known from ordinary intuitionistic propositional calculus can be modified for Intuitionistic Linear Logic (without modalities). The main reductions we consider are: (1) the reduction of the depth of formulas in the sequents by addition of new variables, and (2) the elimination of linear disjunction, tensor and constant F. Both transformations preserve deducibility, that is, a transformed sequent is deducible if and only if the initial one was deducible. The size of the sequent grows linearly in case (1) and ≤ On8 in case (2).
Constructive natural deduction and its ‘ω-set’ interpretation
Authors: Longo Giuseppe , Moggi Eugenio
Published: March 2009

Various Theories of Types are introduced, by stressing the analogy ‘propositions-as-types’: from propositional to higher order types (and Logic). In accordance with this, proofs are described as terms of various calculi, in particular of polymorphic (second order) λ-calculus. A semantic explanation is then given by interpreting individual types and the collection of all types in two simple categories built out of the natural numbers (the modest sets and the universe of ω-sets). The first part of this paper (syntax) may be viewed as a short tutorial with a constructive understanding of the deduction theorem and some work on the expressive power of first and second order quantification. Also in the second part (semantics, §§6–7) the presentation is meant to be elementary, even though we introduce some new facts on types as quotient sets in order to interpret ‘explicit polymorphism’. (The experienced reader in Type Theory may directly go, at first reading, to §§6–8).
A new constructive logic: classic logic
Authors: Girard Jean-Yves
Published: March 2009

There are two ways to present this work; the most efficient is of course to start with the main syntactical definitions, and to end with semantics: this is the presentation that we follow in the body of the text: section 1, syntex; section 2, semantics. Another possibility is to follow the order of discovery of the concepts, which (as expected) starts with the semantics and ends with the syntex; we adopt this second way for our introduction, hoping that this orthogonal look at the same object will help to apprehend the concepts.
Unfold/fold transformations of logic programs
Authors: Shepherdson J. C.
Published: March 2009

Unfold/fold transformations have been used in logic programming for some years to transform programs into more efficient ones. We describe recent work on the extent to which these transformations produce programs which are equivalent to the original one. Various notions of equivalence are considered: same success set; finite failure set; least Herbrand model; completion. This is used to illustrate the rather unsatisfactory relationship between logic programming and logic shown by the wide variety of different declarative semantics proposed for logic programs.
Sheaf semantics for concurrent interacting objects
Authors: Goguen Joseph A.
Published: March 2009

This paper uses concepts from sheaf theory to explain phenomena in concurrent systems, including object, inheritance, deadlock, and non-interference, as used in computer security. The approach is very; general, and applies not only to concurrent object oriented systems, but also to systems of differential equations, electrical circuits, hardware description languages, and much more. Time can be discrete or continuous, linear or branching, and distribution is allowed over space as well as time. Concepts from categpru theory help to achieve this generality: objects are modelled by sheaves; inheritance by sheaf morphisms; systems by diagrams; and interconnection by diagrams of diagrams. In addition, behaviour is given by limit, and the result of interconnection by colimit. The approach is illustrated with many examples, including a semantics for a simple concurrent object-based programming language.
Processes as terms: non-well-founded models for bisimulation
Authors: Rutten J. J. M. M.
Published: March 2009

A compositional semantics characterizing bisimulation equivalence is derived from transition system specifications in the SOS style, satisfying certain syntactic syntactic conditions. We use Aczel's nonstandard set theory for solving a recursive equation for a domain fo processes. It contains non-well-founded elements modelling possibly infinite behaviour. Semantic interpretations of syntactic operators are obtained by defining the operational semantics for terms consisting of both syntactic and semantic (processes)entities. Finally, we return to standard set theory by observing that a similar, though less general, result can be obtained with the use of complete metric spaces.
Categorical models for non-extensional λ-calculi and combinatory logic
Authors: Martini Simone
Published: March 2009

The notions of weak Cartesian closed category and very weak CCC are introduced by dropping the extensionality (and the naturality) requirements in the adjunction defining the closed structure of a CCC. A number of specific examples of these categories are given. The weak notions are shown to be equivalent from both the semantic and syntactic standpoint to the typed non-extensional lambda-calculus and to the typed Combinatory Logic, extended with surjective pairs. Type-free models are characterized as reflexive objects in wCCCs. Finally, categorical models for the second-order non-extensional calculus are defined, by introducing a simple generalization of the notion of PL-category.
Comprehending monads
Authors: Wadler Philip
Published: March 2009

Category theorists invented monads in the 1960's to express concisely certain aspects of universal algebra. Functional programmers invented list comprehensions in the 1970's to express concisely certain programs involving lists. This paper shows how list comprehensions may be generalised to an arbitrary monad, and how the resulting programming feature can express concisely in a pure functional language some programs that manipulate state, handle exceptions, parse text, or invoke continuations. A new solution to the old problem of destructive array update is also presented. No knowledge of category theory is assumed.
Reproducibility of food and nutrient intake estimates using a semi-quantitative FFQ in Australian adults
Authors: Ibiebele Torukiri I , Parekh Sanjoti , Mallitt Kylie-ann , Hughes Maria Celia , O’Rourke Peter K , Webb Penelope M ,   for the Australian Ovarian Cancer Study Group and the Australian Cancer Study
Published: March 2009

Objective

To assess the reproducibility of a 135-item self-administered semi-quantitative FFQ.

Design

Control subjects who had previously completed an FFQ relating to usual dietary intake in a nationwide case–control study of cancer between November 2003 and April 2004 were randomly selected, re-contacted, and invited to complete the same FFQ a second time approximately one year later (between January and April 2005). Agreement between the two FFQ was compared using weighted kappa statistics and intraclass correlation coefficients (ICC) for food groups and nutrients. Summary questions, included in the FFQ, were used to assess overall intakes of vegetables, fruits and meat.

Setting

General community in Australia.

Subjects

One hundred men and women aged 22–79 years, randomly selected from the previous control population.

Results

The weighted κ and ICC measures of agreement for food groups were moderate to substantial for seventeen of the eighteen food groups. For nutrients, weighted κ ranged from 0·44 for starch to 0·83 for alcohol while ICC ranged from 0·51 to 0·91 for the same nutrients. Estimates of meat, fruit and vegetable intake using summary questions were similar for both survey periods, but were significantly lower than estimates from summed individual food items.

Conclusions

The FFQ produced reproducible results and is reasonable in assessing the usual intake of various foods and nutrients among an Australian adult population.
The multidimensional background of malnutrition among rural older individuals in Bangladesh – a challenge for the Millennium Development Goal
Authors: Ferdous Tamanna , Kabir Zarina Nahar , Wahlin Åke , Streatfield Kim , Cederholm Tommy
Published: March 2009

Objective

To investigate the associations and relative impact of illness, socio-economic and social indicators for nutritional status among elderly persons in rural Bangladesh.

Design

A multidisciplinary, cross-sectional study employing home interviews to collect information on demographic, socio-economic and social status; clinical examination to classify medical diagnoses; and Mini Nutritional Assessment (MNA) to assess the nutritional status of each participant.

Setting

Matlab, Bangladesh.

Subjects

A total of 625 randomly selected individuals (≥60 years of age) participated in home interviews and 473 underwent clinical examination. Complete information on nutritional status was available for 457 individuals, median age 68 years, 55 % women.

Results

Twenty-six per cent of the elderly participants were undernourished and 62 % were at risk of malnutrition according to MNA. More than three-quarters of the participants had acute infections, 66 % suffered from chronic illnesses, 36 % had sensory impairments and 81 % were suffering from gastrointestinal disorders. Acute infections (P < 0·001), gastrointestinal disorders (P < 0·01), depressive symptoms (P < 0·001) and impaired cognitive function (P < 0·01) were significantly and independently associated with poorer nutritional status. Moreover, female gender (P < 0·05), having no income (P < 0·01), being illiterate (P < 0·01) and not receiving regular financial support (P < 0·05) were also independently associated with poor nutritional status.

Conclusions

Malnutrition among elderly people in rural Bangladesh is associated with female gender, medical, psychological, socio-economic and social indicators. A multidimensional approach is probably needed to reduce undernutrition in older populations in low-income countries like Bangladesh.
Influence of clouds and diffuse radiation on ecosystem‐atmosphere CO2 and CO18O exchanges
Authors: Still C. J. , Riley W. J. , Biraud S. C. , Noone D. C. , Buenning N. H. , Randerson J. T. , Torn M. S. , Welker J. , White J. W. C. , Vachon R. , Farquhar G. D. , Berry J. A.
Published: March 2009

This study evaluates the potential impact of clouds on ecosystem CO2 and CO2 isotope fluxes (“isofluxes”) in two contrasting ecosystems (a broadleaf deciduous forest and a C4 grassland) in a region for which cloud cover, meteorological, and isotope data are available for driving the isotope‐enabled land surface model (ISOLSM). Our model results indicate a large impact of clouds on ecosystem CO2 fluxes and isofluxes. Despite lower irradiance on partly cloudy and cloudy days, predicted forest canopy photosynthesis was substantially higher than on clear, sunny days, and the highest carbon uptake was achieved on the cloudiest day. This effect was driven by a large increase in light‐limited shade leaf photosynthesis following an increase in the diffuse fraction of irradiance. Photosynthetic isofluxes, by contrast, were largest on partly cloudy days, as leaf water isotopic composition was only slightly depleted and photosynthesis was enhanced, as compared to adjacent clear‐sky days. On the cloudiest day, the forest exhibited intermediate isofluxes: although photosynthesis was highest on this day, leaf‐to‐atmosphere isofluxes were reduced from a feedback of transpiration on canopy relative humidity and leaf water. Photosynthesis and isofluxes were both reduced in the C4 grass canopy with increasing cloud cover and diffuse fraction as a result of near‐constant light limitation of photosynthesis. These results suggest that some of the unexplained variation in global mean δ18O of CO2 may be driven by large‐scale changes in clouds and aerosols and their impacts on diffuse radiation, photosynthesis, and relative humidity.
Carbonyl sulfide as an inverse tracer for biogenic organic carbon in gas and aerosol phases
Authors: de Gouw J. A. , Warneke C. , Montzka S. A. , Holloway J. S. , Parrish D. D. , Fehsenfeld F. C. , Atlas E. L. , Weber R. J. , Flocke F. M.
Published: March 2009

Carbonyl sulfide (COS) is a long‐lived trace gas in the atmosphere with an oceanic source and a surface sink through the uptake by vegetation and soils. We demonstrate the use of COS as an inverse tracer for the impact of biogenic emissions on an air mass including the formation of secondary organic aerosol (SOA). Using airborne data from the summer of 2004 over the northeastern U.S., we find that air masses with reduced COS in the continental boundary layer had on average higher mixing ratios of biogenic VOCs (isoprene, monoterpenes, methanol) and their photo‐oxidation products (methacrolein, methyl vinyl ketone, methyl furan and MPAN, a peroxyacyl nitrate derived from isoprene). Measurements of water‐soluble organic carbon were only weakly correlated with COS, indicating that SOA formation from biogenic precursors was a small contribution to the total.
High‐order oscillatory contributions to shear stress under standing regular wave groups: Theory and experimental evidence
Authors: Sánchez‐Badorrey Elena , Mans Christian , Bramato Simona , Losada Miguel A.
Published: March 2009

In this paper, the oscillatory contributions to the steady shear stress of regular wave groups propagating over plane beds in the laminar regime are investigated theoretically and experimentally. Assuming weak nonlinearity, it was found that weak‐unsteady motions induced by regular wave groups and second‐order harmonics induced by nonlinear bottom boundary layer (BBL) dynamics contribute to the same order. Wave reflection was found to be an additional mechanism to generate high‐order contributions to the steady shear stress. High‐order oscillatory contributions to the steady shear stress generate small‐amplitude perturbations to the steady streaming through the BBL. As a result, steady secondary circulation cells can be distinguished in the wave group–induced BBL. The magnitude and length scale of the measured small‐amplitude perturbations are consistent with the theoretical predictions. Moreover, it is shown that the oscillatory contributions are selected according to their characteristic timescale with distance to the bed. The results could have important implications for understanding BBL dynamics and transport and the transition to the perturbed laminar regime in multiple‐scale oscillatory flows.
Currents in Monterey Submarine Canyon
Authors: Xu J. P. , Noble Marlene A.
Published: March 2009

Flow fields of mean, subtidal, and tidal frequencies between 250 and 3300 m water depths in Monterey Submarine Canyon are examined using current measurements obtained in three yearlong field experiments. Spatial variations in flow fields are mainly controlled by the topography (shape and width) of the canyon. The mean currents flow upcanyon in the offshore reaches (>1000 m) and downcanyon in the shallow reaches (<800 m) of the canyon. Tidal currents, especially the semidiurnal components, are dominant and account for more than 90% of total energy. Pulses of strong currents near the canyon floor, which last several days at a time and have a magnitude as high as 60+ cm/s, are attributed to intense baroclinic processes occurring within the canyon. The V‐shaped canyon walls and the near‐critical slope of the canyon floor focus the baroclinic tides of semidiurnal and higher frequencies to the canyon bottom to produce the >100‐m amplitude isotherm oscillations and associated high‐speed rectilinear currents. The 15‐day spring‐neap cycle and a “3‐day” band are the two prominent frequencies in subtidal flow field. Neither of them seems directly correlated with the spring‐neap cycle of the sea level.
Nonlocal boundary layer: The pure buoyancy‐driven and the buoyancy‐shear‐driven cases
Authors: Colonna N. M. , Ferrero E. , Rizza U.
Published: March 2009

A Reynolds‐averaged Navier‐Stokes (RANS) model including nonlocality was developed and tested. The aim of this paper was to investigate different boundary layer conditions with the RANS model. In particular we focused our attention on boundary layers where convection plays a major role: the shear‐free buoyancy‐driven boundary layer and the buoyancy‐shear‐driven one. We presented a new model which solves dynamical equations for all the turbulence moments up to the third order. The model assumes the fourth‐order moments to be Gaussian‐distributed according to the quasi‐normal approximation. A new approach to avoid the unphysical growth of the third‐order moments, connected to the quasi‐normal hypothesis, is suggested. The new physical ingredient of this method is in essence the parameterization of the relaxation and dissipation time scales related to the return to isotropy terms in the triple‐pressure correlations and to the dissipation rate of the potential temperature variance, respectively. This new parameterization takes into account the dependence of the third‐order moments on the integral length scale of the dissipation rate, a quantity related to the eddy size variation across the boundary layer. The time scales are reduced as the integral length increases, and these reductions provide the proper damping of the turbulent vertical transport. In order to test our model, we carried out large eddy simulations (LESs) of boundary layers with shear and buoyancy. We present the results of the comparison with LESs, aircraft measurements, and DNS, which show that the model performs rather well in all the stability conditions and that the proposed damping gives reliable third‐order moments that satisfy the realizability constraints.
Factors controlling the evolution of the Perdido Fold Belt, northwestern Gulf of Mexico, determined from numerical models
Authors: Gradmann Sofie , Beaumont Christopher , Albertz Markus
Published: March 2009

The Perdido Fold Belt (PFB) is a prominent salt‐cored deep water structure in the northwestern Gulf of Mexico. It is characterized by symmetric, kink‐banded folds of a ∼4.5 km thick prekinematic layer and its vicinity to the extensive Sigsbee Salt Canopy. We use 2‐D finite element numerical models to study the evolution of the PFB as a gravity‐driven fold belt both in a local context and in the context of the larger‐scale passive margin, influenced by adjacent allochthonous salt structures. We show that parameters such as overburden strength, salt geometry, or salt viscosity determine timing, extent, and location of the modeled fold belt. Simplified models of the Gulf of Mexico show that toe‐of‐slope folding is a viable mechanism to develop diapirs in the deep salt basin and to delay folding of the distal overburden. In this scenario, the PFB likely represents the terminal folding of a much larger, diachronously formed fold belt system.
Improving runoff risk estimates: Formulating runoff as a bivariate process using the SCS curve number method
Authors: Shaw Stephen B. , Walter M. Todd
Published: March 2009

The Soil Conservation Service curve number (SCS‐CN) method is widely used to predict storm runoff for hydraulic design purposes, such as sizing culverts and detention basins. As traditionally used, the probability of calculated runoff is equated to the probability of the causative rainfall event, an assumption that fails to account for the influence of variations in soil moisture on runoff generation. We propose a modification to the SCS‐CN method that explicitly incorporates rainfall return periods and the frequency of different soil moisture states to quantify storm runoff risks. Soil moisture status is assumed to be correlated to stream base flow. Fundamentally, this approach treats runoff as the outcome of a bivariate process instead of dictating a 1:1 relationship between causative rainfall and resulting runoff volumes. Using data from the Fall Creek watershed in western New York and the headwaters of the French Broad River in the mountains of North Carolina, we show that our modified SCS‐CN method improves frequency discharge predictions in medium‐sized watersheds in the eastern United States in comparison to the traditional application of the method.
Cobalamin- and Corrinoid-Dependent Enzymes
Authors: Matthews Rowena G.
Published: March 2009

This chapter reviews the literature on cobalamin- and corrinoid-containing enzymes. These enzymes fall into two broad classes, those using methylcobalamin or related methylcorrinoids as prosthetic groups and catalyzing methyl transfer reactions, and those using adenosylcobalamin as the prosthetic group and catalyzing the generation of substrate radicals that in turn undergo rearrangements and/or eliminations.
Management of Adult Vocal Fold Nerve Injury
Authors: Woo Peak , Carroll Linda M.
Published: March 2009

Diagnosis and management of nerve impairment in adults can be difficult due to the myriad of other diagnoses that must be considered. Accurate diagnosis of severity of a nerve impairment and determination of prognostic indicators for return of adequate function are paramount to best management. The strongest prognostic test of nerve function is electromyography. Team management by an otolaryngologist and speech-language pathologist of vocal fold paralysis needs to be sensitive to the patient's needs, both short-term and long-term. This article summarizes the current diagnostic tests and options. Case studies are included to guide the reader through team management and surgical options.
Analysis of recording in bit patterned media with parameter distributions
Authors: Livshitz Boris , Inomata Akihiro , Bertram H. Neal , Lomakin Vitaliy
Published: March 2009

Recording in bit patterned media (BPM) requires strict synchronization of the signal misregistration time. A scheme is presented based on micromagnetic simulation of a single element which allows defining a writing window (WW) permitting for synchronized recording. The WW behavior for random distributions of the anisotropy field is studied. The width of WW is shown to be determined by the medium parameters deviations, the BPM element separation, and the head field strength. It is shown that significant limitations can be imposed on the BPM density and required head fields because of the random distributions of the BPM properties.
The extraordinary Hall effect of SrRuO3 in the ultrathin limit
Authors: Schultz Moty , Reiner James W. , Klein Lior
Published: March 2009

We have measured the temperature dependence of the extraordinary Hall effect (EHE) in ultrathin films of the itinerant ferromagnet SrRuO3. We find that while the resistivity ρ of the films varies significantly with their thickness, the EHE at low temperatures appears to be determined solely by ρ. We discuss possible implications of this observation.
A discrete variable representation method for studying the rovibrational quantum dynamics of molecules with more than three atoms
Authors: Wang Xiao-Gang , Carrington Tucker
Published: March 2009

Established multidimensional discrete variable representations (DVRs) are derived from a direct product basis. They are commonly used to compute vibrational spectra and have also been employed to determine rovibrational spectra of triatomic molecules. We show that for J>0 calculations the DVR is also advantageous for molecules with more than three atoms. We use a basis of products of Wigner functions (for rotation) and DVR functions (for vibration). A key advantage of the DVR is the fact that one can prune the basis: many DVR functions can be discarded from the original direct product basis. This significantly reduces the cost of the calculation. We have implemented a mapping procedure to exploit this prune-ability. We explain how to treat Coriolis terms in a parity-adapted basis. The method is tested by computing rovibrational levels of HFCO.
Brownian dynamics simulations of single-stranded DNA hairpins
Authors: Kenward Martin , Dorfman Kevin D.
Published: March 2009

We present a Brownian dynamics model which we use to study the kinetics and thermodynamics of single-stranded DNA hairpins, gaining insights into the role of stem mismatches and the kinetics rates underlying the melting transition. The model is a base-backbone type in which the DNA bases and sugar-phosphate backbone are represented as single units (beads) in the context of the Brownian dynamics simulations. We employ a minimal number of bead-bead interactions, leading to a simple computational scheme. To demonstrate the veracity of our model for DNA hairpins, we show that the model correctly captures the effects of base stacking, hydrogen bonding, and temperature on both the thermodynamics and the kinetics of hairpin formation and melting. When cast in dimensionless form, the thermodynamic results obtained from the present model compare favorably with default predictions of the m-fold server, although the present model is not sufficiently robust to provide dimensional results. The kinetic data at low temperatures indicate frequent but short-lived opening events, consistent with the measured chain end-to-end probability distribution. The model is also used to study the effect of base mismatches in the stem of the hairpin. With the parameters used here, the model overpredicts the relative shift in the melting temperature due to mismatches. The melting transition can be primarily attributed to a rapid increase in the hairpin opening rate rather than an equivalent decrease in the closing rate, in agreement with single-molecule experimental data.
Femtosecond laser-induced formation of nanometer-width grooves on synthetic single-crystal diamond surfaces
Authors: Shinoda Masataka , Gattass Rafael R. , Mazur Eric
Published: March 2009

We form periodic linear grooves in synthetic single-crystal diamond with femtosecond pulses at 800 nm. The grooves are 40 nm wide, 500 nm deep, up to 0.3 mm long, and have an average spacing of 146±7 nm. The grooves are perpendicular to the direction of the laser polarization and are formed below the threshold for ablation throughout the focal volume. The submicrometer periodicity is caused by interference between a laser-induced plasma and the incident laser beam, which locally enhances the field at the surface so the ablation threshold is exceeded. Using Raman spectroscopy we find that the structures retain the original diamond composition.
Plasma current position measurements in the Korea Superconducting Tokamak Advanced Research device
Authors: Seo Seong-Heon
Published: March 2009

The plasma current position is measured based on the current multipole moment method in the Korea Superconducting Tokamak Advanced Research (KSTAR) device [G. S. Lee et al., Nucl. Fusion 41, 1515 (2001)]. Since a limited number of magnetic probes and flux loops were installed for the first campaign, an iteration method is used to interpolate the magnetic field in the area absent of probes. A numerical technique is developed which automatically compensates for the linear drift of the integrator. The measured plasma position is cross checked with the charge coupled device images. In KSTAR, the plasma current is displaced toward the lower outboard direction during the current initiation phase. This displacement is expected due to eddy currents but the exact amount and direction needs more study.
Influence of noise on the sample entropy algorithm
Authors: Ramdani Sofiane , Bouchara Frédéric , Lagarde Julien
Published: March 2009

We study the effect of static additive noise on the sample entropy (SampEn) algorithm [J. S. Richman and J. R. Moorman, Am. J. Physiol. Heart Circ. Physiol. 278, 2039 (2000); R. B. Govindan et al., Physica A 376, 158 (2007)] for analyzing time series. Using surrogate data tests, we empirically investigate the ability of the SampEn index to detect nonlinearity in simulated time series corrupted by increased amounts of noise. Discrete and continuous chaotic and nonchaotic systems are included in the numerical experiments. Both Gaussian and uniformly distributed noises are considered. The results indicate that the SampEn statistic is a robust index for detecting nonlinearity in time series corrupted by observational noise.