Bob Marsh - Academia.edu (original) (raw)
Papers by Bob Marsh
List of the presentations included in this collection: Welcome (Gerard McCarthy, NUIM) <strong... more List of the presentations included in this collection: Welcome (Gerard McCarthy, NUIM) <strong>Introduction to the observing arrays</strong> NOAC (Martin Moritz, BSH) Greenland-Scotland Ridge (Berit Rabe, MSS) <strong>Observing the Slope Current</strong> The European Slope Current (Martin White, NUIG) Observing and Understanding the Slope Current (Marie Porter and Neil Fraser, SAMS) Decadal predictions (Andre Duesterhus, NUIM) <strong>Modelling in the Eastern Subpolar Gyre</strong> Modelling the Slope Current (Bob Marsh, Univ. Southampton) Nested models on the shelf (Tomasz Dubrowski, Irish Marine Institute)
Regulations for the Use of Theses Unpublished theses submitted for the Master's and Doctor's degr... more Regulations for the Use of Theses Unpublished theses submitted for the Master's and Doctor's degrees and deposited in the Georgia Institute of Technology Library are opens-.for inspection and consultation, but must be used with dup regard for the rights of the authors. Passages may be copied finly with permission of the authors, and proper credit,must bwgiven in subsequent written or published work. Extensive copying or publication of the thesis in whole or in part requires the consent of the Dean of the Graduate Division of the Georgia Institute of Technology.
Life Sciences, 1992
Liver sections removed from phenobarbital induced rats 24 to 48 hours after a 2 hour exposure to ... more Liver sections removed from phenobarbital induced rats 24 to 48 hours after a 2 hour exposure to 1.0% halothane with 10% oxygen and subjected to immunocytochemical treatment showed evidence of centrilobular damage as well as evidence of the production of a protein which has immunoreactivity with anti HSP 72 antibodies. The cells showing evidence of immunoreactivity were within the area of the centrilobular lesion. The level of immunoreactive protein varied directly with the intensity of the lesion. Liver sections from animals treated with phenobarbital alone, phenobarbital plus 10% oxygen, or phenobarbital plus 20% oxygen and 1.0% halothane all were without lesions as well as the immunoreactive protein.
Psychometrika, 1994
This paper presents some results on identification in multitrait-multimethod (MTMM) confirmatory ... more This paper presents some results on identification in multitrait-multimethod (MTMM) confirmatory factor analysis (CFA) models. Some MTMM models are not identified when the (factorial-patterned) loadings matrix is of deficient column rank. For at least one other MTMM model, identification does exist despite such deficiency. It is also shown that for some MTMM CFA models, Howe's (1955) conditions sufficient for rotational uniqueness can fail, yet the model may well be identified and rotationally unique. Implications of these results for CFA models in general are discussed.
Proceedings of the American Mathematical Society, 2007
Cluster algebras are commutative algebras that were introduced by Fomin and Zelevinsky in order t... more Cluster algebras are commutative algebras that were introduced by Fomin and Zelevinsky in order to model the dual canonical basis of a quantum group and total positivity in algebraic groups. Cluster categories were introduced as a representation-theoretic model for cluster algebras. In this article we use this representation-theoretic approach to prove a conjecture of Fomin and Zelevinsky, that for cluster algebras with no coefficients associated to quivers with no oriented cycles, a seed is determined by its cluster. We also obtain an interpretation of the monomial in the denominator of a non-polynomial cluster variable in terms of the composition factors of an indecomposable exceptional module over an associated hereditary algebra.
Neuropathology and Applied Neurobiology, 2002
Introduction: Dermoid cysts constitute 0.3% of all brain tumours. Carcinomatous differentiation ... more Introduction: Dermoid cysts constitute 0.3% of all brain tumours. Carcinomatous differentiation has been described only in a handful of cases. Material and methods: A 44-year-old-man presented with a several-year history of headaches and a 5-week history of progressive visual deterioration in the left eye. Clinical examination confirmed a normal visual acuity but an impaired left visual field. A magnetic resonance imaging scan showed a lesion in the left paraclinoid area compressing the ipsilateral optic nerve. Signal characteristics of the lesion were consistent with a dermoid or epidermoid cyst. At operation, the lesion was thought to be typical of a dermoid cyst and a near-complete excision was achieved leaving behind parts adherent to the optic nerve. Histology showed invasive squamous cell carcinoma arising within the dermoid tumour. Postoperatively the patient received radiotherapy. Results: The patient's clinical condition initially stabilized. At 15 months follow up, however, there was clinical and radiological evidence of tumour progression and he died 1 year later. Conclusion: Squamous cell carcinoma may rarely arise from an intracranial dermoid tumour. This may hinder total excision of the lesion and confounds the prognosis.
Multivariate Behavioral Research, 1999
Multivariate Behavioral Research, 2001
Bong (1998) extended the internal/external frame of reference (I/E) model by attempting to operat... more Bong (1998) extended the internal/external frame of reference (I/E) model by attempting to operationalize the internal and external comparison processes that are central to the model and expanding the range of academic self-concept domains. Bong concluded that the "I/E failed to receive clear support" (p. 102) in relation to predictions that she derived from her extension of the original model. Our critical evaluation and reanalysis, however, reveals potential complications in the operationalization of the internal and external comparisons, the rationale for post hoc confirmatory factor analysis models and the use of correlated uniquenesses, and, thus, the original conclusions. The failure to appropriately operationalize the internal-external distinction based on the items used in the study meant that new tests of this distinction could not be pursued appropriately. The reanalysis, however, provided strong support for the original I/E model and a new extension to incorporate a wider range of academic domains consistent with Bong's original intent.
Mathematische Zeitschrift, 2009
We generalise the notion of cluster structures from the work of Buan-Iyama-Reiten-Scott to includ... more We generalise the notion of cluster structures from the work of Buan-Iyama-Reiten-Scott to include situations where the endomorphism rings of the clusters may have loops. We show that in a Hom-finite 2-Calabi-Yau category, the set of maximal rigid objects satisfies these axioms whenever there are no 2-cycles in the quivers of their endomorphism rings. We apply this result to the cluster category of a tube, and show that this category forms a good model for the combinatorics of a type B cluster algebra.
Management Research News, 1998
Investigates employee benefits on offer in the USA. Acknowledges that several benefits (such as s... more Investigates employee benefits on offer in the USA. Acknowledges that several benefits (such as social security payments) are required by law but focuses on voluntary or discretionary benefits, which may or may not be taxable, such as child care. Explores the purpose of these benefits, particularly from the employ’s point of view, as a tool for offering incentives and increasing motivation. Provides a brief overview of the history of benefits in the USA, the benefits on offer, the cost of benefit packages to employers, and tax consequences. Notes that the traditional benefit package was based on a male worker with a non‐working spouse and two children, which has not kept pace with demographics. Describes a typical household today as a two‐income family with children, with increased life expectancy and more elderly people. Concedes that benefit packages are beginning to change, particularly in relation to elder care and child care. Terms pick and mix benefits packages as cafeteria‐st...
Journal of the London Mathematical Society, 2009
Associated to any acyclic cluster algebra is a corresponding triangulated category known as the c... more Associated to any acyclic cluster algebra is a corresponding triangulated category known as the cluster category. It is known that there is a one-to-one correspondence between cluster variables in the cluster algebra and exceptional indecomposable objects in the cluster category inducing a correspondence between clusters and cluster-tilting objects. Fix a cluster-tilting object T and a corresponding initial cluster. By the Laurent phenomenon, every cluster variable can be written as a Laurent polynomial in the initial cluster. We give conditions on T equivalent to the fact that the denominator in the reduced form for every cluster variable in the cluster algebra has exponents given by the dimension vector of the corresponding module over the endomorphism algebra of T .
The Journal of Higher Education, 2002
Journal of Educational Psychology, 1997
(1996) factor analyzed responses to 4 ability-related self-perceptions (perceived ability, near e... more (1996) factor analyzed responses to 4 ability-related self-perceptions (perceived ability, near expectancies, distant expectancies, and causal attributions) for each of 3 academic domains (math, reading-English, and school). They interpreted their confirmatory factor analysis as supporting the need to distinguish between these 4 self-perceptions as well as the 3 domains and to extend current academic self-concept theories (e.g., H. W. Marsh, 1990, 1993a) that emphasize the domains. Interpretations based on the authors' reanalysis of Simpson et al.'s data contradicted their major conclusions that apparently reflected idiosyncrasies in their items and their methodology, but supported predictions based on previous theory and research. More generally, the authors demonstrate a construct validity approach that blends theory, data, statistical models, and substantive interpretation to validate and compare competing interpretations.
Journal of Educational Psychology, 1997
Newman (1984) examined the causal relations between math self-concept and math achievement in an ... more Newman (1984) examined the causal relations between math self-concept and math achievement in an 8-year longitudinal study using Linear Structural Relations (LISREL) analyses. He concluded that math self-concept did not influence subsequent math achievement. However, the study suffered in that math self-concept was inferred from a single-item scale. Newman addressed this problem, proposed a reasonable solution to it, and based his findings on this solution. However, an alternative solution used in the present reanalysis of his data did support the causal influence of self-concept on subsequent achievement. The purpose of this investigation is to demonstrate the problems associated with single-item indicators in LISREL analyses. The study refutes Newman's conclusion that self-concept has no causal influence on subsequent academic achievement, and argues that it is necessary for such studies to have at least two or more indicators for each latent construct. (Author/JAZ)
Journal of Educational Statistics, 1990
Previous research based on the large, nationally representative High School and Beyond (HSB) stud... more Previous research based on the large, nationally representative High School and Beyond (HSB) study has compared senior year achievement test scores for public and Catholic high school students after controlling for background variables and sophomore year test scores. These analyses, however, were based on traditional applications of multiple regression with its implausible assumptions that variables are measured without error and that residuals are uncorrelated. The present study demonstrates tests for mean differences on latent constructs using the LISREL approach to multigroup structural equation modeling (SEM) for this substantively important issue. Public/Catholic differences, even after controlling for background and sophomore outcomes, favored Catholic high school students on senior year outcomes (achievement, educational aspirations, and academic course selection) and subsequent college attendance. These public/Catholic differences were similar for students differing in race,...
Journal of Algebra, 2006
We investigate the cluster-tilted algebras of finite representation type over an algebraically cl... more We investigate the cluster-tilted algebras of finite representation type over an algebraically closed field. We give an explicit description of the relations for the quivers for finite representation type. As a consequence we show that a (basic) cluster-tilted algebra of finite type is uniquely determined by its quiver. Also some necessary conditions on the shapes of quivers of cluster-tilted algebras of finite representation type are obtained along the way.
British Journal of Neurosurgery, 2005
List of the presentations included in this collection: Welcome (Gerard McCarthy, NUIM) <strong... more List of the presentations included in this collection: Welcome (Gerard McCarthy, NUIM) <strong>Introduction to the observing arrays</strong> NOAC (Martin Moritz, BSH) Greenland-Scotland Ridge (Berit Rabe, MSS) <strong>Observing the Slope Current</strong> The European Slope Current (Martin White, NUIG) Observing and Understanding the Slope Current (Marie Porter and Neil Fraser, SAMS) Decadal predictions (Andre Duesterhus, NUIM) <strong>Modelling in the Eastern Subpolar Gyre</strong> Modelling the Slope Current (Bob Marsh, Univ. Southampton) Nested models on the shelf (Tomasz Dubrowski, Irish Marine Institute)
Regulations for the Use of Theses Unpublished theses submitted for the Master's and Doctor's degr... more Regulations for the Use of Theses Unpublished theses submitted for the Master's and Doctor's degrees and deposited in the Georgia Institute of Technology Library are opens-.for inspection and consultation, but must be used with dup regard for the rights of the authors. Passages may be copied finly with permission of the authors, and proper credit,must bwgiven in subsequent written or published work. Extensive copying or publication of the thesis in whole or in part requires the consent of the Dean of the Graduate Division of the Georgia Institute of Technology.
Life Sciences, 1992
Liver sections removed from phenobarbital induced rats 24 to 48 hours after a 2 hour exposure to ... more Liver sections removed from phenobarbital induced rats 24 to 48 hours after a 2 hour exposure to 1.0% halothane with 10% oxygen and subjected to immunocytochemical treatment showed evidence of centrilobular damage as well as evidence of the production of a protein which has immunoreactivity with anti HSP 72 antibodies. The cells showing evidence of immunoreactivity were within the area of the centrilobular lesion. The level of immunoreactive protein varied directly with the intensity of the lesion. Liver sections from animals treated with phenobarbital alone, phenobarbital plus 10% oxygen, or phenobarbital plus 20% oxygen and 1.0% halothane all were without lesions as well as the immunoreactive protein.
Psychometrika, 1994
This paper presents some results on identification in multitrait-multimethod (MTMM) confirmatory ... more This paper presents some results on identification in multitrait-multimethod (MTMM) confirmatory factor analysis (CFA) models. Some MTMM models are not identified when the (factorial-patterned) loadings matrix is of deficient column rank. For at least one other MTMM model, identification does exist despite such deficiency. It is also shown that for some MTMM CFA models, Howe's (1955) conditions sufficient for rotational uniqueness can fail, yet the model may well be identified and rotationally unique. Implications of these results for CFA models in general are discussed.
Proceedings of the American Mathematical Society, 2007
Cluster algebras are commutative algebras that were introduced by Fomin and Zelevinsky in order t... more Cluster algebras are commutative algebras that were introduced by Fomin and Zelevinsky in order to model the dual canonical basis of a quantum group and total positivity in algebraic groups. Cluster categories were introduced as a representation-theoretic model for cluster algebras. In this article we use this representation-theoretic approach to prove a conjecture of Fomin and Zelevinsky, that for cluster algebras with no coefficients associated to quivers with no oriented cycles, a seed is determined by its cluster. We also obtain an interpretation of the monomial in the denominator of a non-polynomial cluster variable in terms of the composition factors of an indecomposable exceptional module over an associated hereditary algebra.
Neuropathology and Applied Neurobiology, 2002
Introduction: Dermoid cysts constitute 0.3% of all brain tumours. Carcinomatous differentiation ... more Introduction: Dermoid cysts constitute 0.3% of all brain tumours. Carcinomatous differentiation has been described only in a handful of cases. Material and methods: A 44-year-old-man presented with a several-year history of headaches and a 5-week history of progressive visual deterioration in the left eye. Clinical examination confirmed a normal visual acuity but an impaired left visual field. A magnetic resonance imaging scan showed a lesion in the left paraclinoid area compressing the ipsilateral optic nerve. Signal characteristics of the lesion were consistent with a dermoid or epidermoid cyst. At operation, the lesion was thought to be typical of a dermoid cyst and a near-complete excision was achieved leaving behind parts adherent to the optic nerve. Histology showed invasive squamous cell carcinoma arising within the dermoid tumour. Postoperatively the patient received radiotherapy. Results: The patient's clinical condition initially stabilized. At 15 months follow up, however, there was clinical and radiological evidence of tumour progression and he died 1 year later. Conclusion: Squamous cell carcinoma may rarely arise from an intracranial dermoid tumour. This may hinder total excision of the lesion and confounds the prognosis.
Multivariate Behavioral Research, 1999
Multivariate Behavioral Research, 2001
Bong (1998) extended the internal/external frame of reference (I/E) model by attempting to operat... more Bong (1998) extended the internal/external frame of reference (I/E) model by attempting to operationalize the internal and external comparison processes that are central to the model and expanding the range of academic self-concept domains. Bong concluded that the "I/E failed to receive clear support" (p. 102) in relation to predictions that she derived from her extension of the original model. Our critical evaluation and reanalysis, however, reveals potential complications in the operationalization of the internal and external comparisons, the rationale for post hoc confirmatory factor analysis models and the use of correlated uniquenesses, and, thus, the original conclusions. The failure to appropriately operationalize the internal-external distinction based on the items used in the study meant that new tests of this distinction could not be pursued appropriately. The reanalysis, however, provided strong support for the original I/E model and a new extension to incorporate a wider range of academic domains consistent with Bong's original intent.
Mathematische Zeitschrift, 2009
We generalise the notion of cluster structures from the work of Buan-Iyama-Reiten-Scott to includ... more We generalise the notion of cluster structures from the work of Buan-Iyama-Reiten-Scott to include situations where the endomorphism rings of the clusters may have loops. We show that in a Hom-finite 2-Calabi-Yau category, the set of maximal rigid objects satisfies these axioms whenever there are no 2-cycles in the quivers of their endomorphism rings. We apply this result to the cluster category of a tube, and show that this category forms a good model for the combinatorics of a type B cluster algebra.
Management Research News, 1998
Investigates employee benefits on offer in the USA. Acknowledges that several benefits (such as s... more Investigates employee benefits on offer in the USA. Acknowledges that several benefits (such as social security payments) are required by law but focuses on voluntary or discretionary benefits, which may or may not be taxable, such as child care. Explores the purpose of these benefits, particularly from the employ’s point of view, as a tool for offering incentives and increasing motivation. Provides a brief overview of the history of benefits in the USA, the benefits on offer, the cost of benefit packages to employers, and tax consequences. Notes that the traditional benefit package was based on a male worker with a non‐working spouse and two children, which has not kept pace with demographics. Describes a typical household today as a two‐income family with children, with increased life expectancy and more elderly people. Concedes that benefit packages are beginning to change, particularly in relation to elder care and child care. Terms pick and mix benefits packages as cafeteria‐st...
Journal of the London Mathematical Society, 2009
Associated to any acyclic cluster algebra is a corresponding triangulated category known as the c... more Associated to any acyclic cluster algebra is a corresponding triangulated category known as the cluster category. It is known that there is a one-to-one correspondence between cluster variables in the cluster algebra and exceptional indecomposable objects in the cluster category inducing a correspondence between clusters and cluster-tilting objects. Fix a cluster-tilting object T and a corresponding initial cluster. By the Laurent phenomenon, every cluster variable can be written as a Laurent polynomial in the initial cluster. We give conditions on T equivalent to the fact that the denominator in the reduced form for every cluster variable in the cluster algebra has exponents given by the dimension vector of the corresponding module over the endomorphism algebra of T .
The Journal of Higher Education, 2002
Journal of Educational Psychology, 1997
(1996) factor analyzed responses to 4 ability-related self-perceptions (perceived ability, near e... more (1996) factor analyzed responses to 4 ability-related self-perceptions (perceived ability, near expectancies, distant expectancies, and causal attributions) for each of 3 academic domains (math, reading-English, and school). They interpreted their confirmatory factor analysis as supporting the need to distinguish between these 4 self-perceptions as well as the 3 domains and to extend current academic self-concept theories (e.g., H. W. Marsh, 1990, 1993a) that emphasize the domains. Interpretations based on the authors' reanalysis of Simpson et al.'s data contradicted their major conclusions that apparently reflected idiosyncrasies in their items and their methodology, but supported predictions based on previous theory and research. More generally, the authors demonstrate a construct validity approach that blends theory, data, statistical models, and substantive interpretation to validate and compare competing interpretations.
Journal of Educational Psychology, 1997
Newman (1984) examined the causal relations between math self-concept and math achievement in an ... more Newman (1984) examined the causal relations between math self-concept and math achievement in an 8-year longitudinal study using Linear Structural Relations (LISREL) analyses. He concluded that math self-concept did not influence subsequent math achievement. However, the study suffered in that math self-concept was inferred from a single-item scale. Newman addressed this problem, proposed a reasonable solution to it, and based his findings on this solution. However, an alternative solution used in the present reanalysis of his data did support the causal influence of self-concept on subsequent achievement. The purpose of this investigation is to demonstrate the problems associated with single-item indicators in LISREL analyses. The study refutes Newman's conclusion that self-concept has no causal influence on subsequent academic achievement, and argues that it is necessary for such studies to have at least two or more indicators for each latent construct. (Author/JAZ)
Journal of Educational Statistics, 1990
Previous research based on the large, nationally representative High School and Beyond (HSB) stud... more Previous research based on the large, nationally representative High School and Beyond (HSB) study has compared senior year achievement test scores for public and Catholic high school students after controlling for background variables and sophomore year test scores. These analyses, however, were based on traditional applications of multiple regression with its implausible assumptions that variables are measured without error and that residuals are uncorrelated. The present study demonstrates tests for mean differences on latent constructs using the LISREL approach to multigroup structural equation modeling (SEM) for this substantively important issue. Public/Catholic differences, even after controlling for background and sophomore outcomes, favored Catholic high school students on senior year outcomes (achievement, educational aspirations, and academic course selection) and subsequent college attendance. These public/Catholic differences were similar for students differing in race,...
Journal of Algebra, 2006
We investigate the cluster-tilted algebras of finite representation type over an algebraically cl... more We investigate the cluster-tilted algebras of finite representation type over an algebraically closed field. We give an explicit description of the relations for the quivers for finite representation type. As a consequence we show that a (basic) cluster-tilted algebra of finite type is uniquely determined by its quiver. Also some necessary conditions on the shapes of quivers of cluster-tilted algebras of finite representation type are obtained along the way.
British Journal of Neurosurgery, 2005