5,163 research outputs found
Data refinement for true concurrency
The majority of modern systems exhibit sophisticated concurrent behaviour, where several system components modify and observe the system state with fine-grained atomicity. Many systems (e.g., multi-core processors, real-time controllers) also exhibit truly concurrent behaviour, where multiple events can occur simultaneously. This paper presents data refinement defined in terms of an interval-based framework, which includes high-level operators that capture non-deterministic expression evaluation. By modifying the type of an interval, our theory may be specialised to cover data refinement of both discrete and continuous systems. We present an interval-based encoding of forward simulation, then prove that our forward simulation rule is sound with respect to our data refinement definition. A number of rules for decomposing forward simulation proofs over both sequential and parallel composition are developed
A Study on Teacher Evaluation System to Improve Professional Development Among Junior High School Teachers in Ghana
The study examined the perceptions of teachers and supervisors in four circuits from the Oforikrom Municipality in the Ashanti Region of Ghana on the impact of the Teacher Evaluation Process on their classroom practices and professional growth. The study sought to determine to what extent the process of evaluation and the role evaluators played in the process influenced the teacherâs classroom practices and their professional growth. The themes that emerged from the data defined a new teacher-centered interpretation of evaluation and leadership expected of supervisors. The study employed the simple qualitative methodology with narrative inquiry as the method. Interviews were conducted on Twenty-Four (24) participants from 12 schools in 4 circuits. The findings indicated that summative evaluation had prominence over the formative and that increased the level of subjectivity. The study therefore recommended that teacher evaluation be aligned with professional development to establish a positive link between them
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Addressing the Need for New Tourism Theory: The Utility of Constructivist Grounded Theory Methodology for Theory Development
Linda L. Lowry, Ph.D., is an Associate Professor in the Department of Hospitality and Tourism Management in the Isenberg School at UMass-Amherst. Her research and teaching interests include: social, cultural, and economic impacts of tourism and sustainable development. She is a qualitative researcher and locates herself in the constructionist paradigm.
Elizabeth A. Cartier is a Doctoral Candidate in the Department of Hospitality and Tourism Management in the Isenberg School at UMass-Amherst. Her research interests include: host and tourist behavior, tourism culture, and the critical aspects of power and control. Human resources, leadership and tourism are the focus of her teaching.
Robin M. Back is a Doctoral Candidate in the Department of Hospitality and Tourism Management in the Isenberg School at UMass-Amherst. His research interests include: wine tourism and marketing, agi/rural tourism and consumer experience tourism. Events management, beverage management, tourism, and services marketing are the focus of his teaching.
John D. Delconte is a Doctoral Student in the Department of Landscape Architecture and Regional Planning at UMass-Amherst. His research interests include wellness and spiritual tourism, sustainability, cultural tourism, and creative place-making. Oral Presentation, Qualitative Research, Qualitative Research Method
A nonsense mutation in B3GALNT2 is concordant with hydrocephalus in Friesian horses
Background: Hydrocephalus in Friesian horses is a developmental disorder that often results in stillbirth of affected foals and dystocia in dams. The occurrence is probably related to a founder effect and inbreeding in the population. The aim of our study was to find genomic associations, to investigate the mode of inheritance, to allow a DNA test for hydrocephalus in Friesian horses to be developed. In case of a monogenic inheritance we aimed to identify the causal mutation.
Results: A genome-wide association study of hydrocephalus in 13 cases and 69 controls using 29,720 SNPs indicated the involvement of a region on ECA1 (P T corresponding to XP_001491595 p.Gln475* was identical to a B3GALNT2 mutation identified in a human case of muscular dystrophy-dystroglycanopathy with hydrocephalus. All 16 available cases and none of the controls were homozygous for the mutation, and all 17 obligate carriers (= dams of cases) were heterozygous. A random sample of the Friesian horse population (n = 865) was tested for the mutation in a commercial laboratory. One-hundred and forty-seven horses were carrier and 718 horses were homozygous for the normal allele; the estimated allele frequency in the Friesian horse population is 0.085.
Conclusions: Hydrocephalus in Friesian horses has an autosomal recessive mode of inheritance. A nonsense mutation XM_001491545 c.1423C>T corresponding to XP_001491595 p.Gln475* in B3GALNT2 (1: 75,859,296-75,909,376) is concordant with hydrocephalus in Friesian horses. Application of a DNA test in the breeding programme will reduce the losses caused by hydrocephalus in the Friesian horse population
Automated Generation of User Guidance by Combining Computation and Deduction
Herewith, a fairly old concept is published for the first time and named
"Lucas Interpretation". This has been implemented in a prototype, which has
been proved useful in educational practice and has gained academic relevance
with an emerging generation of educational mathematics assistants (EMA) based
on Computer Theorem Proving (CTP).
Automated Theorem Proving (ATP), i.e. deduction, is the most reliable
technology used to check user input. However ATP is inherently weak in
automatically generating solutions for arbitrary problems in applied
mathematics. This weakness is crucial for EMAs: when ATP checks user input as
incorrect and the learner gets stuck then the system should be able to suggest
possible next steps.
The key idea of Lucas Interpretation is to compute the steps of a calculation
following a program written in a novel CTP-based programming language, i.e.
computation provides the next steps. User guidance is generated by combining
deduction and computation: the latter is performed by a specific language
interpreter, which works like a debugger and hands over control to the learner
at breakpoints, i.e. tactics generating the steps of calculation. The
interpreter also builds up logical contexts providing ATP with the data
required for checking user input, thus combining computation and deduction.
The paper describes the concepts underlying Lucas Interpretation so that open
questions can adequately be addressed, and prerequisites for further work are
provided.Comment: In Proceedings THedu'11, arXiv:1202.453
Angular anisotropy of the fusion-fission and quasifission fragments
The anisotropy in the angular distribution of the fusion-fission and
quasifission fragments for the O+U, F+Pb and
S+Pb reactions is studied by analyzing the angular momentum
distributions of the dinuclear system and compound nucleus which are formed
after capture and complete fusion, respectively. The orientation angles of
axial symmetry axes of colliding nuclei to the beam direction are taken into
account for the calculation of the variance of the projection of the total spin
onto the fission axis. It is shown that the deviation of the experimental
angular anisotropy from the statistical model picture is connected with the
contribution of the quasifission fragments which is dominant in the
S+Pb reaction. Enhancement of anisotropy at low energies in the
O+U reaction is connected with quasifission of the dinuclear
system having low temperature and effective moment of inertia.Comment: 17 pages 8 figures. Submitted to Euro. Phys. Jour.
Dwarfism with joint laxity in Friesian horses is associated with a splice site mutation in B4GALT7
Background: Inbreeding and population bottlenecks in the ancestry of Friesian horses has led to health issues such as dwarfism. The limbs of dwarfs are short and the ribs are protruding inwards at the costochondral junction, while the head and back appear normal. A striking feature of the condition is the flexor tendon laxity that leads to hyperextension of the fetlock joints. The growth plates of dwarfs display disorganized and thickened chondrocyte columns. The aim of this study was to identify the gene defect that causes the recessively inherited trait in Friesian horses to understand the disease process at the molecular level.
Results: We have localized the genetic cause of the dwarfism phenotype by a genome wide approach to a 3 Mb region on the p-arm of equine chromosome 14. The DNA of two dwarfs and one control Friesian horse was sequenced completely and we identified the missense mutation ECA14:g.4535550C> T that cosegregated with the phenotype in all Friesians analyzed. The mutation leads to the amino acid substitution p.(Arg17Lys) of xylosylprotein beta 1,4-galactosyltransferase 7 encoded by B4GALT7. The protein is one of the enzymes that synthesize the tetrasaccharide linker between protein and glycosaminoglycan moieties of proteoglycans of the extracellular matrix. The mutation not only affects a conserved arginine codon but also the last nucleotide of the first exon of the gene and we show that it impedes splicing of the primary transcript in cultured fibroblasts from a heterozygous horse. As a result, the level of B4GALT7 mRNA in fibroblasts from a dwarf is only 2 % compared to normal levels. Mutations in B4GALT7 in humans are associated with Ehlers-Danlos syndrome progeroid type 1 and Larsen of Reunion Island syndrome. Growth retardation and ligamentous laxity are common manifestations of these syndromes.
Conclusions: We suggest that the identified mutation of equine B4GALT7 leads to the typical dwarfism phenotype in Friesian horses due to deficient splicing of transcripts of the gene. The mutated gene implicates the extracellular matrix in the regular organization of chrondrocyte columns of the growth plate. Conservation of individual amino acids may not be necessary at the protein level but instead may reflect underlying conservation of nucleotide sequence that are required for efficient splicing
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