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Robert Gray

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Universidad Nacional de Colombia (National University of Colombia)

Armando Marques-Guedes

UNL - New University of Lisbon

University of Zurich, Switzerland

Thomás A S Haddad

Universidade de São Paulo

Daniel Hershenzon

University of Connecticut

Dokuz Eylül University

Zhejiang University

Shih-shan Susan Huang 黃士珊

Rice University

Leibniz-Institut für Europäische Geschichte (IEG), Mainz

Pasquale Terracciano

University of Rome Tor Vergata

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Papers by Robert Gray

Lossy compression of clustered-dot halftones

Proceedings of 1st International Conference on Image Processing

Page 1. LOSSY COMPRESSION OF CLUSTERED-DOT HALFTONES Rick A. Vander Kam and Robert M. Gray Inform... more

Unbalanced tree-growing algorithms for practical image compression

[Proceedings] ICASSP 91: 1991 International Conference on Acoustics, Speech, and Signal Processing, 1991

A vector quantization compression system is presented which is suitable for use in commercial app... more A vector quantization compression system is presented which is suitable for use in commercial applications, i.e., efficient enough to encode a wide variety of images and simple enough to decode the images in real time using software (for machine compatibility). A fixed-rate code with unbalanced tree structure is used, and a method of unbalanced tree growing is extended. Simple prediction techniques are applied to improve coded image quality

Performance of Microwave and Millimeter Wave Power Modules (MPMs) with Linearization

MILCOM 2005 - 2005 IEEE Military Communications Conference, 2005

Microwave and millimeter wave power modules (MPMs) provide compact, low mass and highly efficient... more Microwave and millimeter wave power modules (MPMs) provide compact, low mass and highly efficient power amplification for frequencies from S through Q-band. When combined with a linearizer they can provide the most efficient compact linear microwave and millimeter wave amplification in the 50 to 200 watt power range. This paper will present the most current performance achieved by combining predistortion linearizers with MPMs. Measured performance will be provided for a variety of linearized MPMs including octave bandwidth and multi-band applications for frequencies through Qband.

Wideband TWTA linearized driver amplifier for Ka-band satellites

18th International Communications Satellite Systems Conference and Exhibit, 2000

Toward Interoperability of Mobile-Agent Systems

Lecture Notes in Computer Science, 2002

Growing recognition of the benefits of mobile agents in distributed systems, such as military C4I... more Growing recognition of the benefits of mobile agents in distributed systems, such as military C4ISR, has led to a proliferation of mobile agent systems. However, incompatibilities between proprietary systems prevent the greater potential benefits of ubiquitous mobile agent computing. In particular, agents cannot migrate to a host that runs a different mobile-agent system. Prior approaches to interoperability have tried to force agents to use a common API and so far none have succeeded. This goal led to our efforts to develop mechanisms that support runtime interoperability of mobile-agent systems. This paper describes the Grid Mobile-Agent System, which allows agents to migrate to different mobile-agent systems.

RF Coupling Simulation Model Development for Optimal Placement of Antennas Supporting Wireless Communications Systems

2009 Joint Rail Conference, 2009

The locomotive cab’s limited rooftop area requires that the transmitting and receiving antennas f... more The locomotive cab’s limited rooftop area requires that the transmitting and receiving antennas for communications be placed in close proximity to one another. Currently, no means exist to aid the railroad radio frequency (RF) engineer in placing these antennas so that mutual communications interference is minimized. The goal of this paper is to describe a method that can be used to determine optimal antenna placement in a time- and cost-effective manner. The method described below utilizes various forms of the Friis transmission equation in Monte Carlo simulations.Copyright © 2009 by ASME

A case of recurrent giant cell tumor of bone with malignant transformation and benign pulmonary metastases

Diagnostic pathology, Jan 22, 2010

Giant cell tumor (GCT) of bone is a locally destructive tumor that occurs predominantly in long b... more Giant cell tumor (GCT) of bone is a locally destructive tumor that occurs predominantly in long bones of post-pubertal adolescents and young adults, where it occurs in the epiphysis. The majority are treated by aggressive curettage or resection. Vascular invasion outside the boundary of the tumor can be seen. Metastasis, with identical morphology to the primary tumor, occurs in a few percent of cases, usually to the lung. On occasion GCTs of bone undergo frank malignant transformation to undifferentiated sarcomas. Here we report a case of GCT of bone that at the time of recurrence was found to have undergone malignant transformation. Concurrent metastases were found in the lung, but these were non-transformed GCT.

Visually guided collision avoidance and collision achievement

Trends in Cognitive Sciences, 2000

To survive on today's highways, a driver must have highly developed skills in visually guided col... more To survive on today's highways, a driver must have highly developed skills in visually guided collision avoidance. To play such games as cricket, tennis or baseball demands accurate, precise and reliable collision achievement. This review discusses evidence that some of these tasks are performed by predicting where an object will be at some sharply defined instant, several hundred milliseconds in the future, while other tasks are performed by utilizing the fact that some of our motor actions change what we see in ways that obey lawful relationships, and can therefore be learned. Several monocular and binocular visual correlates of the direction of an object's motion relative to the observer's head have been derived theoretically, along with visual correlates of the time to collision with an approaching object. Although laboratory psychophysics can identify putative neural mechanisms by showing which of the known correlates are processed by the human visual system independently of other visual information, it is only field research on, for example, driving, aviation and sport that can show which visual cues are actually used in these activities. This article reviews this research and describes a general psychophysically based rational approach to the design of such field studies.

Computer programs and mathematical proofs

The Mathematical Intelligencer, 1991

In his Mathematical Intelligencer article [2] about computer science and mathematics, E. W. Dijks... more In his Mathematical Intelligencer article [2] about computer science and mathematics, E. W. Dijkstra states that "the techniques of program design h a v e . . , successfully been applied to proof design." This article provides examples of Dijkstra's statement. How do we know that this procedure terminates? And that it produces a finite subcover? Answering these questions requires a mathematical proof about its behavior. This proof uses the procedure's call tree, which is formed by the procedure calls that occur

Maximal subgroups of free idempotent-generated semigroups over the full transformation monoid

Proceedings of the London Mathematical Society, 2012

Let T n be the full transformation semigroup of all mappings from the set {1, . . . , n} to itsel... more Let T n be the full transformation semigroup of all mappings from the set {1, . . . , n} to itself under composition. Let E = E(T n ) denote the set of idempotents of T n and let e ∈ E be an arbitrary idempotent satisfying |im (e)| = r ≤ n -2. We prove that the maximal subgroup of the free idempotent generated semigroup over E containing e is isomorphic to the symmetric group S r .

Do Monocular Time-to-Collision Estimates Necessarily Involve Perceived Distance?

Perception, 1999

Motivated by the debate between indirect and direct theories of perception, a large number of res... more Motivated by the debate between indirect and direct theories of perception, a large number of researchers have attempted to determine whether judgments of time to collision are based on the ratio of perceived distance to perceived speed or on the ratio θ/(d θ/d t), ie tau. Despite the considerable research effort devoted to this question there seems to be no clear resolution. We used a staircase tracking procedure to estimate errors in estimating time to collision for a simulated approaching object. To investigate the role of perceived distance in the judgment of time to collision, we asked observers to alternate between two viewing distances (100 and 500 cm). For the 500 cm viewing distance, we magnified the visual display by a factor of five so that the retinal images [and the values of θ/(d θ/d t) through time] were identical for the two viewing distances. All visual cues to distance were available. There were no significant differences between estimates of time to collision made...

Growth from Birth to Early Adolescence in Offspring Prenatally Exposed to Cigarettes and Marijuana

Neurotoxicology and Teratology, 1999

Weight, height, and head circumference were examined in children from birth to early adolescence ... more Weight, height, and head circumference were examined in children from birth to early adolescence for whom prenatal exposure to marijuana and cigarettes had been ascertained. The subjects were from a low-risk, predominantly middle-class sample participating in an ongoing longitudinal study. The negative association between growth measures at birth and prenatal cigarette exposure was overcome, sooner in males than females, within the first few years, and by the age of six, the children of heavy smokers were heavier than control subjects. Pre and postnatal environmental tobacco smoke did not have a negative effect upon the growth parameters; however, the choice of bottle-feeding or shorter duration of breast-feeding by women who smoked during pregnancy appeared to play an important positive role in the catch-up observed among the infants of smokers. Prenatal exposure to marijuana was not significantly related to any growth measures at birth, although a smaller head circumference observed at all ages reached statistical significance among the early adolescents born to the heavy marijuana users.

Effects of growth hormone treatment on very-low-density lipoprotein apolipoprotein B100 turnover in adult hypopituitarism

Metabolism, 2000

Adult hypopituitarism is associated with hyperlipidemia, mainly due to an increase of very-low-de... more Adult hypopituitarism is associated with hyperlipidemia, mainly due to an increase of very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) levels. Recent studies have shown that such patients exhibit increased hepatic secretion of VLDL apolipoprotein B100 (VLDL apo B100). To examine the effects of growth hormone (GH) replacement on VLDL apo B100 turnover, 13 GH-deficient hypopituitary patients (8 women and 5 men; aged 47 _+ 3 years, mean -+ SEM; body mass index [BMI], 30 -+ 2 kg/m z) entered a double-blind placebo-controlled study for 6 months (GH 0.125 IU/kg/wk for 4 weeks, and then 0.25 IU/kg/wk). GH was subsequently used in all patients for a further 6 months. A 5-hour [1-13C] leucine infusion was administered at baseline and at 6 months. The secretion rate of VLDL apo B100 was derived by kinetic analysis following quantitation of isotopic enrichment by gas chromatography/mass spectrometry. The GH-treated group (6 patients) demonstrated a similar fractional secretion rate (FSR) for VLDL apo B100 at 0 and 6 months. The pool size and absolute secretion rate (ASR) also were unaffected significantly by GH therapy. No significant changes were observed in the placebo group (7 patients). Treatment with GH for 6 months caused an increase in the high-density lipoprotein (HDL) cholesterol concentration (13 patients, 1.27 -+ 0.13 v 1.16 _+ 0.10 mmol/L, respectively, P = .05), whereas total cholesterol and triglyceride concentrations did not change. Nonesterified fatty acids (NEFAs) increased during GH therapy (471 _ 43 i~mol/L at 6 months v 349 -49 i~mol/L at baseline, P < .0005). The data suggest that GH does not affect VLDL apo B100 turnover in a significant way.

An intelligent business forecaster for strategic business planning

Journal of Forecasting, 1999

In this paper an intelligent business forecaster for strategic business planning is presented. Th... more

Set-homogeneous directed graphs

Journal of Combinatorial Theory, Series B, 2012

A directed graph is set-homogeneous if, whenever U and V are isomorphic finite subdigraphs, there... more A directed graph is set-homogeneous if, whenever U and V are isomorphic finite subdigraphs, there is an automorphism g of the digraph with U g = V . Here, extending work of Lachlan on finite homogeneous digraphs, we classify finite set-homogeneous digraphs, where we allow some pairs of vertices to have arcs in both directions. Under the assumption that such pairs of vertices are not allowed, we obtain initial results on countably infinite set-homogeneous digraphs, classifying those which are not 2-homogeneous.

Hemiparesis Is a Clinical Correlate of General Adaptive Dysfunction in Children and Adolescents with Sturge-Weber Syndrome

Journal of Child Neurology, 2009

This study sought to identify neurologic correlates of adaptive functioning in individuals with S... more This study sought to identify neurologic correlates of adaptive functioning in individuals with Sturge-Weber syndrome. A total of 18 children, adolescents, and young adults with Sturge-Weber syndrome with brain involvement were recruited from our Sturge-Weber center. All underwent neurologic examination (including review of clinical brain magnetic resonance imaging) and neuropsychological assessment. Neuropsychological assessment included measures of intellectual ability and standardized parent report of adaptive functioning. Overall, Full Scale IQ and ratings of global adaptive functioning were both lower than the population-based norms (P < .05). Negative correlations were identified between adaptive functioning ratings, clinician ratings of cortical abnormality, and ratings of neurologic status. Hemiparesis (minimal versus prominent) was the only individual component of the rating scales that differentiated between individuals with nonimpaired and impaired adaptive functioning...

Topics in the two-dimensional sampling and reconstruction of images

International Journal of Remote Sensing, 1984

The arrival of the new generation of satellite sensors with improved spatial and radiometric reso... more The arrival of the new generation of satellite sensors with improved spatial and radiometric resolution (Thematic Mapper and SPOT) requires a re-evaluation of techniques for system performance analysis. Furthermore, the high performance of these systems will place greater demands on resampling algorithms for geometric processing of the imagery. Both of these topics are discussed. A formalism for incorporating random sample-scene

The Aristocracy of Labour in Nineteenth-Century Britain, 1850-1914

The Economic History Review, 1982

THUS George Potter, prominent trade unionist and radical journalist. Similar phrases are scattere... more THUS George Potter, prominent trade unionist and radical journalist. Similar phrases are scattered through contemporary accounts of the working class in the third quarter of the nineteenth century, emphasising the role of an ‘aristocracy of the working classes’ distinguished from other workers by their way of life, values and attitudes, as much as by a superior economic position. They were often seen as a moderating influence on the politics of popular protest, contributing to the mid-century disintegration of mass movements such as Chartism. Historians following the lines of enquiry suggested by this contemporary analysis have adopted the term ‘labour aristocracy’ to indicate such groupings within the working class. How valid are these attempts to identify a distinct upper stratum? And how did divisions within the working class affect the militancy and class consciousness of the labour movement in the decades after 1850? Studies of the labour aristocracy continue to provoke a lively debate around these problems.

Locally-finite connected-homogeneous digraphs

Discrete Mathematics, 2011

A digraph is connected-homogeneous if any isomorphism between finite connected induced subdigraph... more A digraph is connected-homogeneous if any isomorphism between finite connected induced subdigraphs extends to an automorphism of the digraph. We consider locally-finite connectedhomogeneous digraphs with more than one end. In the case that the digraph embeds a triangle we give a complete classification, obtaining a family of tree-like graphs constructed by gluing together directed triangles. In the triangle-free case we show that these digraphs are highly arc-transitive. We give a classification in the two-ended case, showing that all examples arise from a simple construction given by gluing along a directed line copies of some fixed finite directed complete bipartite graph. When the digraph has infinitely many ends we show that the descendants of a vertex form a tree, and the reachability graph (which is one of the basic building blocks of the digraph) is one of: an even cycle, a complete bipartite graph, the complement of a perfect matching, or an infinite semiregular tree. We give examples showing that each of these possibilities is realised as the reachability graph of some connected-homogeneous digraph, and in the process we obtain a new family of highly arc-transitive digraphs without property Z.

Generating Sets of Completely 0-Simple Semigroups

Communications in Algebra, 2005

A formula for the rank of an arbitrary finite completely 0 -simple semigroup, represented as a Re... more A formula for the rank of an arbitrary finite completely 0 -simple semigroup, represented as a Rees matrix semigroup M 0 [G; I, Λ; P ] , is given. The result generalises that of Ruškuc concerning the rank of connected finite completely 0 -simple semigroups. The rank is expressed in terms of |I| , |Λ| , the number of connected components k of P and a number rmin which we define. We go on to show that the number rmin is expressible in terms of a family of subgroups of G the members of which are in one to one correspondence with, and determined by the non-zero entries of, the components of P . A number of applications are given, including a generalisation of a result of Gomes and Howie concerning the rank of an arbitrary Brandt semigroup B(G, {1, . . . , n}) .

Lossy compression of clustered-dot halftones

Proceedings of 1st International Conference on Image Processing

Page 1. LOSSY COMPRESSION OF CLUSTERED-DOT HALFTONES Rick A. Vander Kam and Robert M. Gray Inform... more

Unbalanced tree-growing algorithms for practical image compression

[Proceedings] ICASSP 91: 1991 International Conference on Acoustics, Speech, and Signal Processing, 1991

A vector quantization compression system is presented which is suitable for use in commercial app... more A vector quantization compression system is presented which is suitable for use in commercial applications, i.e., efficient enough to encode a wide variety of images and simple enough to decode the images in real time using software (for machine compatibility). A fixed-rate code with unbalanced tree structure is used, and a method of unbalanced tree growing is extended. Simple prediction techniques are applied to improve coded image quality

Performance of Microwave and Millimeter Wave Power Modules (MPMs) with Linearization

MILCOM 2005 - 2005 IEEE Military Communications Conference, 2005

Microwave and millimeter wave power modules (MPMs) provide compact, low mass and highly efficient... more Microwave and millimeter wave power modules (MPMs) provide compact, low mass and highly efficient power amplification for frequencies from S through Q-band. When combined with a linearizer they can provide the most efficient compact linear microwave and millimeter wave amplification in the 50 to 200 watt power range. This paper will present the most current performance achieved by combining predistortion linearizers with MPMs. Measured performance will be provided for a variety of linearized MPMs including octave bandwidth and multi-band applications for frequencies through Qband.

Wideband TWTA linearized driver amplifier for Ka-band satellites

18th International Communications Satellite Systems Conference and Exhibit, 2000

Toward Interoperability of Mobile-Agent Systems

Lecture Notes in Computer Science, 2002

Growing recognition of the benefits of mobile agents in distributed systems, such as military C4I... more Growing recognition of the benefits of mobile agents in distributed systems, such as military C4ISR, has led to a proliferation of mobile agent systems. However, incompatibilities between proprietary systems prevent the greater potential benefits of ubiquitous mobile agent computing. In particular, agents cannot migrate to a host that runs a different mobile-agent system. Prior approaches to interoperability have tried to force agents to use a common API and so far none have succeeded. This goal led to our efforts to develop mechanisms that support runtime interoperability of mobile-agent systems. This paper describes the Grid Mobile-Agent System, which allows agents to migrate to different mobile-agent systems.

RF Coupling Simulation Model Development for Optimal Placement of Antennas Supporting Wireless Communications Systems

2009 Joint Rail Conference, 2009

The locomotive cab’s limited rooftop area requires that the transmitting and receiving antennas f... more The locomotive cab’s limited rooftop area requires that the transmitting and receiving antennas for communications be placed in close proximity to one another. Currently, no means exist to aid the railroad radio frequency (RF) engineer in placing these antennas so that mutual communications interference is minimized. The goal of this paper is to describe a method that can be used to determine optimal antenna placement in a time- and cost-effective manner. The method described below utilizes various forms of the Friis transmission equation in Monte Carlo simulations.Copyright © 2009 by ASME

A case of recurrent giant cell tumor of bone with malignant transformation and benign pulmonary metastases

Diagnostic pathology, Jan 22, 2010

Giant cell tumor (GCT) of bone is a locally destructive tumor that occurs predominantly in long b... more Giant cell tumor (GCT) of bone is a locally destructive tumor that occurs predominantly in long bones of post-pubertal adolescents and young adults, where it occurs in the epiphysis. The majority are treated by aggressive curettage or resection. Vascular invasion outside the boundary of the tumor can be seen. Metastasis, with identical morphology to the primary tumor, occurs in a few percent of cases, usually to the lung. On occasion GCTs of bone undergo frank malignant transformation to undifferentiated sarcomas. Here we report a case of GCT of bone that at the time of recurrence was found to have undergone malignant transformation. Concurrent metastases were found in the lung, but these were non-transformed GCT.

Visually guided collision avoidance and collision achievement

Trends in Cognitive Sciences, 2000

To survive on today's highways, a driver must have highly developed skills in visually guided col... more To survive on today's highways, a driver must have highly developed skills in visually guided collision avoidance. To play such games as cricket, tennis or baseball demands accurate, precise and reliable collision achievement. This review discusses evidence that some of these tasks are performed by predicting where an object will be at some sharply defined instant, several hundred milliseconds in the future, while other tasks are performed by utilizing the fact that some of our motor actions change what we see in ways that obey lawful relationships, and can therefore be learned. Several monocular and binocular visual correlates of the direction of an object's motion relative to the observer's head have been derived theoretically, along with visual correlates of the time to collision with an approaching object. Although laboratory psychophysics can identify putative neural mechanisms by showing which of the known correlates are processed by the human visual system independently of other visual information, it is only field research on, for example, driving, aviation and sport that can show which visual cues are actually used in these activities. This article reviews this research and describes a general psychophysically based rational approach to the design of such field studies.

Computer programs and mathematical proofs

The Mathematical Intelligencer, 1991

In his Mathematical Intelligencer article [2] about computer science and mathematics, E. W. Dijks... more In his Mathematical Intelligencer article [2] about computer science and mathematics, E. W. Dijkstra states that "the techniques of program design h a v e . . , successfully been applied to proof design." This article provides examples of Dijkstra's statement. How do we know that this procedure terminates? And that it produces a finite subcover? Answering these questions requires a mathematical proof about its behavior. This proof uses the procedure's call tree, which is formed by the procedure calls that occur

Maximal subgroups of free idempotent-generated semigroups over the full transformation monoid

Proceedings of the London Mathematical Society, 2012

Let T n be the full transformation semigroup of all mappings from the set {1, . . . , n} to itsel... more Let T n be the full transformation semigroup of all mappings from the set {1, . . . , n} to itself under composition. Let E = E(T n ) denote the set of idempotents of T n and let e ∈ E be an arbitrary idempotent satisfying |im (e)| = r ≤ n -2. We prove that the maximal subgroup of the free idempotent generated semigroup over E containing e is isomorphic to the symmetric group S r .

Do Monocular Time-to-Collision Estimates Necessarily Involve Perceived Distance?

Perception, 1999

Motivated by the debate between indirect and direct theories of perception, a large number of res... more Motivated by the debate between indirect and direct theories of perception, a large number of researchers have attempted to determine whether judgments of time to collision are based on the ratio of perceived distance to perceived speed or on the ratio θ/(d θ/d t), ie tau. Despite the considerable research effort devoted to this question there seems to be no clear resolution. We used a staircase tracking procedure to estimate errors in estimating time to collision for a simulated approaching object. To investigate the role of perceived distance in the judgment of time to collision, we asked observers to alternate between two viewing distances (100 and 500 cm). For the 500 cm viewing distance, we magnified the visual display by a factor of five so that the retinal images [and the values of θ/(d θ/d t) through time] were identical for the two viewing distances. All visual cues to distance were available. There were no significant differences between estimates of time to collision made...

Growth from Birth to Early Adolescence in Offspring Prenatally Exposed to Cigarettes and Marijuana

Neurotoxicology and Teratology, 1999

Weight, height, and head circumference were examined in children from birth to early adolescence ... more Weight, height, and head circumference were examined in children from birth to early adolescence for whom prenatal exposure to marijuana and cigarettes had been ascertained. The subjects were from a low-risk, predominantly middle-class sample participating in an ongoing longitudinal study. The negative association between growth measures at birth and prenatal cigarette exposure was overcome, sooner in males than females, within the first few years, and by the age of six, the children of heavy smokers were heavier than control subjects. Pre and postnatal environmental tobacco smoke did not have a negative effect upon the growth parameters; however, the choice of bottle-feeding or shorter duration of breast-feeding by women who smoked during pregnancy appeared to play an important positive role in the catch-up observed among the infants of smokers. Prenatal exposure to marijuana was not significantly related to any growth measures at birth, although a smaller head circumference observed at all ages reached statistical significance among the early adolescents born to the heavy marijuana users.

Effects of growth hormone treatment on very-low-density lipoprotein apolipoprotein B100 turnover in adult hypopituitarism

Metabolism, 2000

Adult hypopituitarism is associated with hyperlipidemia, mainly due to an increase of very-low-de... more Adult hypopituitarism is associated with hyperlipidemia, mainly due to an increase of very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) levels. Recent studies have shown that such patients exhibit increased hepatic secretion of VLDL apolipoprotein B100 (VLDL apo B100). To examine the effects of growth hormone (GH) replacement on VLDL apo B100 turnover, 13 GH-deficient hypopituitary patients (8 women and 5 men; aged 47 _+ 3 years, mean -+ SEM; body mass index [BMI], 30 -+ 2 kg/m z) entered a double-blind placebo-controlled study for 6 months (GH 0.125 IU/kg/wk for 4 weeks, and then 0.25 IU/kg/wk). GH was subsequently used in all patients for a further 6 months. A 5-hour [1-13C] leucine infusion was administered at baseline and at 6 months. The secretion rate of VLDL apo B100 was derived by kinetic analysis following quantitation of isotopic enrichment by gas chromatography/mass spectrometry. The GH-treated group (6 patients) demonstrated a similar fractional secretion rate (FSR) for VLDL apo B100 at 0 and 6 months. The pool size and absolute secretion rate (ASR) also were unaffected significantly by GH therapy. No significant changes were observed in the placebo group (7 patients). Treatment with GH for 6 months caused an increase in the high-density lipoprotein (HDL) cholesterol concentration (13 patients, 1.27 -+ 0.13 v 1.16 _+ 0.10 mmol/L, respectively, P = .05), whereas total cholesterol and triglyceride concentrations did not change. Nonesterified fatty acids (NEFAs) increased during GH therapy (471 _ 43 i~mol/L at 6 months v 349 -49 i~mol/L at baseline, P < .0005). The data suggest that GH does not affect VLDL apo B100 turnover in a significant way.

An intelligent business forecaster for strategic business planning

Journal of Forecasting, 1999

In this paper an intelligent business forecaster for strategic business planning is presented. Th... more

Set-homogeneous directed graphs

Journal of Combinatorial Theory, Series B, 2012

A directed graph is set-homogeneous if, whenever U and V are isomorphic finite subdigraphs, there... more A directed graph is set-homogeneous if, whenever U and V are isomorphic finite subdigraphs, there is an automorphism g of the digraph with U g = V . Here, extending work of Lachlan on finite homogeneous digraphs, we classify finite set-homogeneous digraphs, where we allow some pairs of vertices to have arcs in both directions. Under the assumption that such pairs of vertices are not allowed, we obtain initial results on countably infinite set-homogeneous digraphs, classifying those which are not 2-homogeneous.

Hemiparesis Is a Clinical Correlate of General Adaptive Dysfunction in Children and Adolescents with Sturge-Weber Syndrome

Journal of Child Neurology, 2009

This study sought to identify neurologic correlates of adaptive functioning in individuals with S... more This study sought to identify neurologic correlates of adaptive functioning in individuals with Sturge-Weber syndrome. A total of 18 children, adolescents, and young adults with Sturge-Weber syndrome with brain involvement were recruited from our Sturge-Weber center. All underwent neurologic examination (including review of clinical brain magnetic resonance imaging) and neuropsychological assessment. Neuropsychological assessment included measures of intellectual ability and standardized parent report of adaptive functioning. Overall, Full Scale IQ and ratings of global adaptive functioning were both lower than the population-based norms (P < .05). Negative correlations were identified between adaptive functioning ratings, clinician ratings of cortical abnormality, and ratings of neurologic status. Hemiparesis (minimal versus prominent) was the only individual component of the rating scales that differentiated between individuals with nonimpaired and impaired adaptive functioning...

Topics in the two-dimensional sampling and reconstruction of images

International Journal of Remote Sensing, 1984

The arrival of the new generation of satellite sensors with improved spatial and radiometric reso... more The arrival of the new generation of satellite sensors with improved spatial and radiometric resolution (Thematic Mapper and SPOT) requires a re-evaluation of techniques for system performance analysis. Furthermore, the high performance of these systems will place greater demands on resampling algorithms for geometric processing of the imagery. Both of these topics are discussed. A formalism for incorporating random sample-scene

The Aristocracy of Labour in Nineteenth-Century Britain, 1850-1914

The Economic History Review, 1982

THUS George Potter, prominent trade unionist and radical journalist. Similar phrases are scattere... more THUS George Potter, prominent trade unionist and radical journalist. Similar phrases are scattered through contemporary accounts of the working class in the third quarter of the nineteenth century, emphasising the role of an ‘aristocracy of the working classes’ distinguished from other workers by their way of life, values and attitudes, as much as by a superior economic position. They were often seen as a moderating influence on the politics of popular protest, contributing to the mid-century disintegration of mass movements such as Chartism. Historians following the lines of enquiry suggested by this contemporary analysis have adopted the term ‘labour aristocracy’ to indicate such groupings within the working class. How valid are these attempts to identify a distinct upper stratum? And how did divisions within the working class affect the militancy and class consciousness of the labour movement in the decades after 1850? Studies of the labour aristocracy continue to provoke a lively debate around these problems.

Locally-finite connected-homogeneous digraphs

Discrete Mathematics, 2011

A digraph is connected-homogeneous if any isomorphism between finite connected induced subdigraph... more A digraph is connected-homogeneous if any isomorphism between finite connected induced subdigraphs extends to an automorphism of the digraph. We consider locally-finite connectedhomogeneous digraphs with more than one end. In the case that the digraph embeds a triangle we give a complete classification, obtaining a family of tree-like graphs constructed by gluing together directed triangles. In the triangle-free case we show that these digraphs are highly arc-transitive. We give a classification in the two-ended case, showing that all examples arise from a simple construction given by gluing along a directed line copies of some fixed finite directed complete bipartite graph. When the digraph has infinitely many ends we show that the descendants of a vertex form a tree, and the reachability graph (which is one of the basic building blocks of the digraph) is one of: an even cycle, a complete bipartite graph, the complement of a perfect matching, or an infinite semiregular tree. We give examples showing that each of these possibilities is realised as the reachability graph of some connected-homogeneous digraph, and in the process we obtain a new family of highly arc-transitive digraphs without property Z.

Generating Sets of Completely 0-Simple Semigroups

Communications in Algebra, 2005

A formula for the rank of an arbitrary finite completely 0 -simple semigroup, represented as a Re... more A formula for the rank of an arbitrary finite completely 0 -simple semigroup, represented as a Rees matrix semigroup M 0 [G; I, Λ; P ] , is given. The result generalises that of Ruškuc concerning the rank of connected finite completely 0 -simple semigroups. The rank is expressed in terms of |I| , |Λ| , the number of connected components k of P and a number rmin which we define. We go on to show that the number rmin is expressible in terms of a family of subgroups of G the members of which are in one to one correspondence with, and determined by the non-zero entries of, the components of P . A number of applications are given, including a generalisation of a result of Gomes and Howie concerning the rank of an arbitrary Brandt semigroup B(G, {1, . . . , n}) .