2,162 research outputs found
Formal Foundations for the Specification of Software Architecture
This investigation establishes a formal foundation for software architecture that allows for the specification of large, non-trivial software systems using well founded, consistency preserving construction techniques. Two fundamental problems were addressed: how to define and express architectures formally using the concept of theories, and how architecture theories can be practically applied in specification construction. The initial stages of this investigation sought to establish a formal, mathematical relationship between functional specifications of behavior and specifications defining system structure. Experimental results lead to the conclusion that architectures defining the structure of functional operations can be defined using functional logic, but more complex architectures require a separate process logic. A process logic based on Hoare\u27s Communicating Sequential Processes (CSP) was selected for representing and reasoning about system structure and was used in the definition of a process-based specification development system. Specifically, CSP was used to define a category of process-based specifications and specification morphisms. This allowed well-founded specification construction techniques such as specification morphisms, colimits, and interpretations to be applied to the construction of consistent software architecture. Architecture theories expressed in terms of functional and process-based specifications were defined, and translations between these architecture theories were investigated. A feasibility analysis on an image processing application demonstrated that architecture theories can be used to develop specifications for large, non-trivial applications. (KAR) P. 2
Self-Esteem and Interpersonal Relationships
Problem: What a person thinks of himself and how he gets along with others are issues of crucial concern in our families, our churches, and in our community. Some Seventh-day Adventist Christians have tended to believe that an emphasis on propositional theology will automatically make Christians better people, but this is shown to be inadequate. Indeed Adventist teaching has always insisted man functions best in four dimensions. It was the purpose of this project to focus on a relational theology as well as some of the important principles of psychology and sociology to see to what extent an understanding of these things would bring about a growth in self esteem and interpersonal relationships.
Method: Two human relationship workshops were conducted in different Adventist Churches to establish an environment in which there would be freedom to examine, discuss, communicate, experience, and evaluate relationship issues. The workshops were structured around lectures and group dynamics. The first workshop was conducted at Hillview Seventh-day Adventist Church over nine weeks with an average attendance of fifty-eight and the second at Kurri Kurri Seventh-day Adventist Church over five weeks with an average attendance of eighteen.
Results: The evidence from the objective and subjective data gathered at the workshops indicated that the majority of participants experienced significant growth in self esteem, interpersonal relationships and the ability to manage personal conflicts.
Conclusion: Systematic human relationship training can effectively aid in the development of one\u27s self concept and interpersonal relationships. It appears that regardless of the size of the group some degree of increase in relational growth will take place. It is felt that this training is an important part of developing the Body of Christ so it can function as He desired. By this all men will know you are my disciples, if you have love for one another (John 13:35)
Wide range and tunable linear TMR sensor using two exchange pinned electrodes
A magnetic tunnel junction sensor is proposed, with both the detection and
the reference layers pinned by IrMn. Using the differences in the blocking
temperatures of the IrMn films with different thicknesses, crossed anisotropies
can be induced between the detection and the reference electrodes. The pinning
of the sensing electrode ensures a linear and reversible output. It also allows
tuning both the sensitivity and the linear range of the sensor. The authors
show that the sensitivity varies linearly with the ferromagnetic thickness of
the detection electrode. It is demonstrated that an increased thickness leads
to a rise of sensitivity and a reduction of the operating range
Heterotic-string amplitudes at one loop: modular graph forms and relations to open strings
We investigate one-loop four-point scattering of non-abelian gauge bosons in heterotic string theory and identify new connections with the corresponding open-string amplitude. In the low-energy expansion of the heterotic-string amplitude, the integrals over torus punctures are systematically evaluated in terms of modular graph forms, certain non-holomorphic modular forms. For a specific torus integral, the modular graph forms in the low-energy expansion are related to the elliptic multiple zeta values from the analogous open-string integrations over cylinder boundaries. The detailed correspondence between these modular graph forms and elliptic multiple zeta values supports a recent proposal for an elliptic generalization of the single-valued map at genus zero
Conformational Preferences of 3-(Dimethylazinoyl)propanoic Acid as a Function of pH and Solvent; Intermolecular versus Intramolecular Hydrogen Bonding
The conformational equilibrium of 3-(dimethylazinoyl)propanoic acid (DMAPA, azinoyl = N^+(O^−) has a weak pH-dependence in D_2O, with a slight preference for trans in alkaline solutions. The acid ionization constants of the protonated amine oxide and carboxylic functional groups as determined by NMR spectroscopy were 7.9 × 10^(−4) and 6.3 × 10^(−6), respectively. The corresponding value of K_1/K_2 of 1.3 × 10^2 is not deemed large enough to provide experimental NMR evidence for a significant degree of intramolecular hydrogen bonding in D_2O. Conformational preferences of DMAPA are mostly close to statistical (gauche/trans = 2/1) in other protic solvents, e.g., alcohols. However, the un-ionized form of DMAPA appears to be strongly intramolecularly hydrogen-bonded and gauche in aprotic solvents
Coulomb-U and magnetic moment collapse in -Pu
The around-the-mean-field version of the LDA+U method is applied to
investigate electron correlation effects in -Pu. It yields a
non-magnetic ground state of Pu, and provides a good agreement with
experimental equilibrium volume, bulk modulus and explains important features
of the photoelectron spectra
Shifting CCR7 towards Its Monomeric Form Augments CCL19 Binding and Uptake.
The chemokine receptor CCR7, together with its ligands, is responsible for the migration and positioning of adaptive immune cells, and hence critical for launching adaptive immune responses. CCR7 is also induced on certain cancer cells and contributes to metastasis formation. Thus, CCR7 expression and signalling must be tightly regulated for proper function. CCR7, like many other members of the G-protein coupled receptor superfamily, can form homodimers and oligomers. Notably, danger signals associated with pathogen encounter promote oligomerisation of CCR7 and is considered as one layer of regulating its function. Here, we assessed the dimerisation of human CCR7 and several single point mutations using split-luciferase complementation assays. We demonstrate that dimerisation-defective CCR7 mutants can be transported to the cell surface and elicit normal chemokine-driven G-protein activation. By contrast, we discovered that CCR7 mutants whose expression are shifted towards monomers significantly augment their capacities to bind and internalise fluorescently labelled CCL19. Modeling of the receptor suggests that dimerisation-defective CCR7 mutants render the extracellular loops more flexible and less structured, such that the chemokine recognition site located in the binding pocket might become more accessible to its ligand. Overall, we provide new insights into how the dimerisation state of CCR7 affects CCL19 binding and receptor trafficking
FastaValidator: an open-source Java library to parse and validate FASTA formatted sequences
Background: Advances in sequencing technologies challenge the efficient importing and validation of FASTA formatted sequence data which is still a prerequisite for most bioinformatic tools and pipelines. Comparative analysis of commonly used Bio*-frameworks (BioPerl, BioJava and Biopython) shows that their scalability and accuracy is hampered. Findings: FastaValidator represents a platform-independent, standardized, light-weight software library written in the Java programming language. It targets computer scientists and bioinformaticians writing software which needs to parse quickly and accurately large amounts of sequence data. For end-users FastaValidator includes an interactive out-of-the-box validation of FASTA formatted files, as well as a non-interactive mode designed for high-throughput validation in software pipelines. Conclusions: The accuracy and performance of the FastaValidator library qualifies it for large data sets such as those commonly produced by massive parallel (NGS) technologies. It offers scientists a fast, accurate and standardized method for parsing and validating FASTA formatted sequence data
Behavioral and Imaging Studies of Infant Artificial Grammar Learning
Artificial grammar learning (AGL) paradigms have proven to be productive and useful to investigate how young infants break into the grammar of their native language(s). The question of when infants first show the ability to learn abstract grammatical rules has been central to theoretical debates about the innate vs. learned nature of grammar. The presence of this ability early in development, that is, before considerable experience with language, has been argued to provide evidence for a biologically endowed ability to acquire language. Artificial grammar learning tasks also allow infant populations to be readily compared with adults and non-human animals. Artificial grammar learning paradigms with infants have been used to investigate a number of linguistic phenomena and learning tasks, from word segmentation to phonotactics and morphosyntax. In this review, we focus on AGL studies testing infants\u2019 ability to learn grammatical/structural properties of language. Specifically, we discuss the results of AGL studies focusing on repetition-based regularities, the categorization of functors, adjacent and non-adjacent dependencies, and word order. We discuss the implications of the results for a general theory of language acquisition, and we outline some of the open questions and challenges
Distinct Fates of Chemokine and Surrogate Molecule Gradients: Consequences for CCR7-Guided Dendritic Cell Migration.
Chemokine-guided leukocyte migration is a hallmark of the immune system to cope with invading pathogens. Intruder confronted dendritic cells (DCs) induce the expression of the chemokine receptor CCR7, which enables them to sense and migrate along chemokine gradients to home to draining lymph nodes, where they launch an adaptive immune response. Chemokine-mediated DC migration is recapitulated and intensively studied in 3D matrix migration chambers. A major caveat in the field is that chemokine gradient formation and maintenance in such 3D environments is generally not assessed. Instead, fluorescent probes, mostly labelled dextran, are used as surrogate molecules, thereby neglecting important electrochemical properties of the chemokines. Here, we used site-specifically, fluorescently labelled CCL19 and CCL21 to study the establishment and shape of the chemokine gradients over time in the 3D collagen matrix. We demonstrate that CCL19 and particularly CCL21 establish stable, but short-distance spanning gradients with an exponential decay-like shape. By contrast, dextran with its neutral surface charge forms a nearly linear gradient across the entire matrix. We show that the charged C-terminal tail of CCL21, known to interact with extracellular matrix proteins, is determinant for shaping the chemokine gradient. Importantly, DCs sense differences in the shape of CCL19 and CCL21 gradients, resulting in distinct spatial migratory responses
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