1,721,124 research outputs found
The Study of the Helix-Coil Transition of Polyglutamic Acid in the Presence of the Cupric Ion
No full textSince Pauling and Corey (1) proposed the well ordered helix conformation of polyamino acids, great interest has been shown concerning their behavior in solvent systems. Doty et. al,, (2) in 1957 showed evidence that solvent conditions, including pH, could effect this helical structure. There was strong evidence that the helical structure, if its environment were changed enough, would undergo a conformational change to a random coil, the random coil being a considerably less ordered structure. It was evident that when this conformational change took place, the physical properties of this system also changed. | It is an interesting study in itself to examine and evaluate the different methods of measuring or observing this helix-coil transition. Probably the most obvious indication of the conformational change is the viscosity. (2) While this physical property shows the transition well, it does not enable one to calculate what percent of the total number of polymer residues is involved in the helix, and what part is involved in the coil. Such a method was proposed (3), however, which correlates the helix content with the optical rotatory dispersion (ORD). At the present time, the ORD method is taken as the standard procedure for determining helix content. By use of the ORD, the percent helicity has been related to other physical properties and their changes for systems undergoing the transition.ProQuest Traditional Publishing Optio
PROV-N: The Provenance Notation
No full textProvenance is information about entities, activities, and people involved in producing a piece of data or thing, which can be used to form assessments about its quality, reliability or trustworthiness. PROV-DM is the conceptual data model that forms a basis for the W3C provenance (PROV) family of specifications. PROV-DM distinguishes core structures, forming the essence of provenance information, from extended structures catering for more specific uses of provenance. PROV-DM is organized in six components, respectively dealing with: (1) entities and activities, and the time at which they were created, used, or ended; (2) derivations of entities from entities; (3) agents bearing responsibility for entities that were generated and activities that happened; (4) a notion of bundle, a mechanism to support provenance of provenance; and, (5) properties to link entities that refer to the same thing; (6) collections forming a logical structure for its members. To provide examples of the PROV data model, the PROV notation (PROV-N) is introduced: aimed at human consumption, PROV-N allows serializations of PROV instances to be created in a compact manner. PROV-N facilitates the mapping of the PROV data model to concrete syntax, and is used as the basis for a formal semantics of PROV. The purpose of this document is to define the PROV-N notation
The Rationale of PROV
Full text linkThe PROV family of documents are the final output of the World Wide Web Consortium Provenance Working Group, chartered to specify a representation of provenance to facilitate its exchange over the Web. This article reflects upon the key requirements, guiding principles, and design decisions that influenced the PROV family of documents. A broad range of requirements were found, relating to the key concepts necessary for describing provenance, such as resources, activities, agents and events, and to balancing prov’s ease of use with the facility to check its validity. By this retrospective requirement analysis, the article aims to provide some insights into how prov turned out as it did and why. Benefits of this insight include better inter-operability, a roadmap for alternate investigations and improvements, and solid foundations for future standardization activities
Principles of Provenance (Dagstuhl Seminar 12091)
No full textThis report documents the program and the outcomes of Dagstuhl Seminar 12091 ``Principles of Provenance''. The term ``provenance'' refers to information about the origin, context, derivation, ownership or history of some artifact. In both art and science, provenance information is crucial for establishing the value of a real-world artifact, guaranteeing for example that the artifact is an original work produced by an important artist, or that a stated scientific conclusion is reproducible. Since it is much easier to copy or alter digital information than it is to copy or alter real-world artifacts, the need for tracking and management of provenance information to testify the value and correctness of digital information has been firmly established in the last few years. As a result, provenance tracking and management has been studied in many settings, ranging from databases, scientific workflows, business process modeling, and security to social networking and the Semantic Web, but with relatively few interaction between these areas. This Dagstuhl seminar has focused on bringing together researchers from the above and other areas to identify the commonalities and differences of dealing with provenance; improve the mutual understanding of these communities; and identify main areas for further foundational provenance research
Uranalysis as a means of diagnosis in veterinary diseases
Full text linkCitation: Cheney, James Hamilton. Uranalysis as a means of diagnosis in veterinary diseases. Senior thesis, Kansas State Agricultural College, 1907.Morse Department of Special CollectionsIntroduction: Since uranalysis has come to be a very important factor in the diagnosis of human diseases, it seems reasonable that it might be of some aid in veterinary practice. While it may not be practical for the veterinarian to be so precise or accurate in his calculations as is the human physician, it seems reasonable that he make some use of the subject. For example, it is a comparatively easy matter in the human practice to collect all the urine excreted in twenty-four hours, while in veterinary practice this would be attended with more difficulty. This difficulty:, however, may be remedied somewhat by taking the sample the first thing in the morning. If the composition of the urine is an index of what is going on in the tissues it remains only for us to be able to recognize healthy and diseased conditions and to be able to make the tests fairly accurately. If one becomes familiar with uranalysis and its significance it can be made as valuable a means of diagnosing many diseases as any of the other methods at our disposal
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Data provenance, curation and quality in metrology
Full text linkData metrology -- the assessment of the quality of data -- particularly in
scientific and industrial settings, has emerged as an important requirement for
the UK National Physical Laboratory (NPL) and other national metrology
institutes. Data provenance and data curation are key components for emerging
understanding of data metrology. However, to date provenance research has had
limited visibility to or uptake in metrology. In this work, we summarize a
scoping study carried out with NPL staff and industrial participants to
understand their current and future needs for provenance, curation and data
quality. We then survey provenance technology and standards that are relevant
to metrology. We analyse the gaps between requirements and the current state of
the art
Provenance Management in Curated Databases
Full text linkCurated databases in bioinformatics and other disciplines are the result of a great deal of manual annotation, correction and transfer of data from other sources. Provenance information concerning the creation, attribution, or version history of such data is crucial for assessing its integrity and scientific value. General purpose database systems provide little support for tracking provenance, especially when data moves among databases. This paper investigates general-purpose techniques for recording provenance for data that is copied among databases. We describe an approach in which we track the user's actions while browsing source databases and copying data into a curated database, in order to record the user's actions in a convenient, queryable form. We present an implementation of this technique and use it to evaluate the feasibility of database support for provenance management. Our experiments show that although the overhead of a na ve approach is fairly high, it can be decreased to an acceptable level using simple optimizations
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
