CiteULike: Author Byrne

Structural Equation Modeling With AMOS: Basic Concepts, Applications, and Programming (Multivariate Applications Series)

Barbara Byrne — 2008-08-15T12:58:47-00:00

(01 April 2001)

This book illustrates the ease with which AMOS 4.0 can be used to address research questions that lend themselves to structural equation modeling (SEM). This goal is achieved by: 1) presenting a nonmathematical introduction to the basic concepts and applications of structural equation modeling; 2) demonstrating basic applications of SEM using AMOS 4.0; and 3) highlighting features of AMOS 4.0 that address important caveats related to SEM analyses. Written in a "user-friendly" style, the author "walks" the reader through 10 SEM applications from model specification to estimation to the assessment and interpretation of the output. Each of the book's applications is accompanied by: *a statement of the hypothesis being tested; *a schematic representation of the model under study; *the use and function of a wide variety of icons and pull-down menus; *a full explanation of related AMOS Graphic input models and output files; *a model input file based on AMOS BASIC; and *the published reference from which each application was drawn.

A two-fluid model for tissue growth within a dynamic flow environment

RD O'Dea — 2008-08-15T10:22:09-00:00

European Journal of Applied Mathematics, Vol. Forthcoming, No. -1. (2008), pp. 1-28.

We study the growth of a tissue construct in a perfusion bioreactor, focussing on its response to the mechanical environment. The bioreactor system is modelled as a two-dimensional channel containing a tissue construct through which a flow of culture medium is driven. We employ a multiphase formulation of the type presented by G. Lemon, J. King, H. Byrne, O. Jensen and K. Shakesheff in their study (Multiphase modelling of tissue growth using the theory of mixtures. J. Math. Biol. 52(2), 2006, 571–594) restricted to two interacting fluid phases, representing a cell population (and attendant extracellular matrix) and a culture medium, and employ the simplifying limit of large interphase viscous drag after S. Franks in her study (Mathematical Modelling of Tumour Growth and Stability. Ph.D. Thesis, University of Nottingham, UK, 2002) and S. Franks and J. King in their study (Interactions between a uniformly proliferating tumour and its surrounding: Uniform material properties. Math. Med. Biol. 20, 2003, 47–89).

Bivalirudin versus Unfractionated Heparin during Percutaneous Coronary Intervention

Adnan Kastrati — 2008-08-15T01:44:53-00:00

N Engl J Med, Vol. 359, No. 7. (14 August 2008), pp. 688-696.

Background Whether bivalirudin is superior to unfractionated heparin in patients with stable or unstable angina who undergo percutaneous coronary intervention (PCI) after pretreatment with clopidogrel is unknown. Methods We enrolled 4570 patients with stable or unstable angina (with normal levels of troponin T and creatine kinase MB) who were undergoing PCI after pretreatment with a 600-mg dose of clopidogrel at least 2 hours before the procedure; 2289 patients were randomly assigned in a double-blind manner to receive bivalirudin, and 2281 to receive unfractionated heparin. The primary end point was the composite of death, myocardial infarction, urgent target-vessel revascularization due to myocardial ischemia within 30 days after randomization, or major bleeding during the index hospitalization (with a net clinical benefit defined as a reduction in the incidence of the end point). The secondary end point was the composite of death, myocardial infarction, or urgent target-vessel revascularization. Results The incidence of the primary end point was 8.3% (190 patients) in the bivalirudin group as compared with 8.7% (199 patients) in the unfractionated-heparin group (relative risk, 0.94; 95% confidence interval [CI], 0.77 to 1.15; P=0.57). The secondary end point occurred in 134 patients (5.9%) in the bivalirudin group and 115 patients (5.0%) in the unfractionated-heparin group (relative risk, 1.16; 95% CI, 0.91 to 1.49; P=0.23). The incidence of major bleeding was 3.1% (70 patients) in the bivalirudin group and 4.6% (104 patients) in the unfractionated-heparin group (relative risk, 0.66; 95% CI, 0.49 to 0.90; P=0.008). Conclusions In patients with stable and unstable angina who underwent PCI after pretreatment with clopidogrel, bivalirudin did not provide a net clinical benefit (i.e., it did not reduce the incidence of the composite end point of death, myocardial infarction, urgent target-vessel revascularization, or major bleeding) as compared with unfractionated heparin, but it did significantly reduce the incidence of major bleeding. (ClinicalTrials.gov number, NCT00262054 .) 10.1056/NEJMoa0802944

Managing the acute psychotic episode.

P Byrne — 2007-04-21T01:12:23-00:00

BMJ, Vol. 334, No. 7595. (31 March 2007), pp. 686-692.

Presence and activity of anaerobic ammonium-oxidizing bacteria at deep-sea hydrothermal vents.

Nathalie Byrne — 2008-08-04T19:39:27-00:00

The ISME journal (31 July 2008)

Recent studies indicate that ammonia is an important electron donor for the oxidation of fixed nitrogen, both in the marine water column and sediments. This process, known as anammox, has so far only been observed in a large range of temperature habitats. The present study investigated the role of anammox in hydrothermal settings. During three oceanographic expeditions to the Mid-Atlantic Ridge, hydrothermal samples were collected from five vent sites, at depths ranging from 750 to 3650 m from cold to hot habitats. Evidence for the occurrence of anammox in these particular habitats was demonstrated by concurrent surveys, including the amplification of 16S rRNA gene sequences related to known anammox bacteria, ladderanes lipids analysis and measurement of a (14)N(15)N dinitrogen production in isotope-pairing experiments at 60 and 85 degrees C. Together these results indicate that new deep-branching anammox bacteria may be active in these hot habitats.The ISME Journal advance online publication, 31 July 2008; doi:10.1038/ismej.2008.72.

Clinicopathologic and diagnostic imaging characteristics of systemic aspergillosis in 30 dogs.

RM Schultz — 2008-07-30T21:10:18-00:00

Journal of veterinary internal medicine / American College of Veterinary Internal Medicine, Vol. 22, No. 4. (g 2008), pp. 851-859.

Background: Systemic aspergillosis is a serious disease of dogs for which the clinical characteristics are poorly described. Objective: To describe the clinical and diagnostic imaging characteristics of dogs with systemic aspergillosis. Animals: Thirty dogs with systemic aspergillosis. Methods: Retrospective case review. Medical records were reviewed for signalment, clinical features, and results of clinicopathologic testing and diagnostic imaging. Diagnosis was confirmed by culture of Aspergillus terreus (n = 13), Aspergillus deflectus (n = 11), or other Aspergillus spp. (n = 6). Results: Compared with the background hospital population, German Shepherd dogs and female dogs were overrepresented (odds ratio [OR] 43, 95% confidence interval [CI] 20-91, P < .0001, and OR 2.9, 95% CI 1.2-6.7, P= .02), respectively, with 20 of the 30 dogs being German Shepherd dogs and 77% (23 of 30) of the dogs being female. The median age was 4.5 years (range 2-8 years). Anemia, leukocytosis, hyperglobulinemia, azotemia, hypercalcemia, and hypoalbuminemia were present in 8, 21, 12, 9, 8, and 6 dogs, respectively. Diskospondylitis, osteomyelitis and thoracic lymphadenomegaly were present in 16, 10, and 5 dogs, respectively. Sonographic findings were enlarged hypoechoic lymph nodes (n = 12), mottled and irregular kidneys with or without masses (n = 12), pyelectasia, and an aggregate of echogenic material in the renal pelvis (n = 9). Thirteen dogs were treated with antifungal drugs, with survival times ranging from 0 to 25 months after diagnosis. Conclusions and Clinical Importance: Systemic aspergillosis typically involves young to middle-age female German Shepherd dogs, and there are characteristic abdominal ultrasound findings with the disease process. Infection with A. deflectus was as common as A. terreus, and in rare cases, long-term survival was associated with antifungal therapy.

Spider monkey ranging patterns in Mexican subtropical forest: do travel routes reflect planning?

Valero — 2007-08-26T05:14:27-00:00

Animal Cognition, Vol. 10, No. 3. (July 2007), pp. 305-315.

What wild primates know about resources: opening up the black box

Janson — 2007-08-26T05:14:26-00:00

Animal Cognition, Vol. 10, No. 3. (July 2007), pp. 357-367.

Image Retrieval Using Natural Language and Content-Based Techniques

Kate Byrne — 2008-07-23T18:51:20-00:00

This MSc thesis deals with the application of Natural Language Processing and ContentBased Image Retrieval to the practical problem of finding database images to answer user queries. The data collection used contains about 50,000 digital images linked to a large text database. In contrast to many otherwise similar image retrieval projects, the text used comes from a range of data fields, not just captions individually linked to images. The data relates to archaeology and architectural history, ...

Multiple rounds of speciation associated with reciprocal gene loss in polyploid yeasts

Devin Scannell — 2006-03-15T23:36:34-00:00

Nature, Vol. 440, No. 7082., pp. 341-345.

Haemodynamic simulation of aneurysm coiling in an anatomically accurate computational fluid dynamics model: technical note

Aristotelis Mitsos — 2008-07-22T09:17:08-00:00

Neuroradiology, Vol. 50, No. 4. (27 April 2008), pp. 341-347.

Abstract Introduction Computational fluid dynamics (CFD) is a numerical technique that is used for studying haemodynamic parameters in cerebral aneurysms. As it is now possible to represent an anatomically accurate intracranial aneurysm in a computational model, we have attempted to simulate its endosaccular occlusion with coils and demonstrate the haemodynamic changes induced. This is the first attempt to use this particular porous medium-based method for coiling simulation in a CFD model, to our knowledge. Methods Datasets from a rotational 3-D digital subtraction angiogram of a recently ruptured anterior communicating aneurysm were converted into a 3-D geometric model and the discretized data were processed using the computational technique developed. Coiling embolisation simulation was achieved by impediment of flow through a porous medium with characteristics following a series of embolisation coils. Haemodynamic parameters studied were: pressure distribution on the vessel wall, blood velocity and blood flow patterns. Results Significant haemodynamic changes were detected after deployment of the first coil. Similar, but less dramatic changes occurred during subsequent stages of coiling. The blood flow patterns became less vortical in the aneurysm sac as velocity decreased to stagnation and the wall pressure at the fundus was gradually reduced. Furthermore, the haemodynamic characteristics developed at the area of the neck remnant could form the basis for assessing the likelihood of delayed coil compaction and aneurysm regrowth. Conclusion Appropriate computational techniques show great promise in simulating the haemodynamic behaviour of the various stages in coil embolisation and may be a potentially valuable tool in interventional planning and procedural decision-making.

Producing primate embryonic stem cells by somatic cell nuclear transfer

J Byrne — 2007-11-15T08:53:50-00:00

Nature (14 November 2007)

Machiavellian Intelligence : Social Expertise and the Evolution of Intellect in Monkeys, Apes, and Humans (Oxford Science Publications)

Richard Byrne — 2006-06-15T13:36:28-00:00

(14 September 1989)

This book presents an alternative to conventional ideas about the evolution of the human intellect. Instead of placing top priority on the role of tools, the pressure for their skillful use, and the related importance of interpersonal communication as a means for enhanced cooperation, this volume explores quite a different idea-- that the driving force in the evolution of human intellect was social expertise--a force which enabled the manipulation of others within the social group, who themselves are seen as posing the most challenging problems faced by primitive humans. The need to outwit one's clever colleagues then produces an evolutionary spiraling of "Machiavellian intelligence." The book forms a complete and self-contained text on this fast-growing topic. It includes the origins of the basic premise and a wealth of exciting developments, described by an international team of authors from the fields of anthropology, psychology, and zoology. An evaluation of more traditional approaches is also undertaken, with a view to discovering to what extent Machiavellian intelligence represents a complementary concept or one that is truly an alternative. Readers and students will find this fascinating volume carries them to the frontiers of scientific work on the origin of human intellect.

Severe brain injury to neurological determination of death: Canadian forum recommendations.

SD Shemie — 2008-07-03T14:11:47-00:00

CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, Vol. 174, No. 6. (14 March 2006)

Mathematical modelling of engineered tissue growth using a multiphase porous flow mixture theory

Greg Lemon — 2008-06-30T12:34:29-00:00

Journal of Mathematical Biology, Vol. 52, No. 5. (23 May 2006), pp. 571-594.

Abstract This paper outlines the framework of a porous flow mixture theory for the mathematical modelling of in vitro tissue growth, and gives an application of this theory to an aspect of tissue engineering. The problem is formulated as a set of partial differential equations governing the space and time dependence of the amounts of each component of the tissue (phase), together with the physical stresses in each component. The theory requires constitutive relations to specify the material properties of each phase, and also requires relations to specify the stresses developed due to mechanical interactions, both within each phase and between different phases. An application of the theory is given to the study of the mobility and aggregation of a population of cells seeded into an artificial polymeric scaffold. Stability analysis techniques show that the interplay of the forces between the tissue constituents results in two different regimes: either the cells form aggregates or disperse through the scaffold.

Modelling solid tumour growth using the theory of mixtures

Helen Byrne — 2008-06-30T12:29:20-00:00

Math Med Biol, Vol. 20, No. 4. (1 December 2003), pp. 341-366.

In this paper the theory of mixtures is used to develop a two-phase model of an avascular tumour, which comprises a solid, cellular, phase and a liquid phase. Mass and momentum balances which are used to derive the governing equations are supplemented by constitutive laws that distinguish the two phases and enable the stresses within the tumour to be calculated. Novel features of the model include the dependence of the cell proliferation rate on the cellular stress and the incorporation of mass exchange between the two phases. A combination of numerical and analytical techniques is used to investigate the sensitivity of equilibrium tumour configurations to changes in the model parameters. Variation of parameters such as the maximum cell proliferation rate and the rate of natural cell death yield results which are consistent with analyses performed on simpler tumour growth models and indicate that the two-phase formulation is a natural extension of the earlier models. New predictions relate to the impact of mechanical effects on the tumour's equilibrium size which decreases under increasing stress and/or external loading. In particular, as a parameter which measures the reduction in cell proliferation due to cell stress is increased a critical value is reached, above which the tumour is eliminated. 10.1093/imammb/20.4.341

A principle for learning egocentric-allocentric transformation.

P Byrne — 2008-06-27T18:22:32-00:00

Neural computation, Vol. 20, No. 3. (March 2008), pp. 709-737.

Numerous single-unit recording studies have found mammalian hippocampal neurons that fire selectively for the animal's location in space, independent of its orientation. The population of such neurons, commonly known as place cells, is thought to maintain an allocentric, or orientation-independent, internal representation of the animal's location in space, as well as mediating long-term storage of spatial memories. The fact that spatial information from the environment must reach the brain via sensory receptors in an inherently egocentric, or viewpoint-dependent, fashion leads to the question of how the brain learns to transform egocentric sensory representations into allocentric ones for long-term memory storage. Additionally, if these long-term memory representations of space are to be useful in guiding motor behavior, then the reverse transformation, from allocentric to egocentric coordinates, must also be learned. We propose that orientation-invariant representations can be learned by neural circuits that follow two learning principles: minimization of reconstruction error and maximization of representational temporal inertia. Two different neural network models are presented that adhere to these learning principles, the first by direct optimization through gradient descent and the second using a more biologically realistic circuit based on the restricted Boltzmann machine (Hinton, 2002; Smolensky, 1986). Both models lead to orientation-invariant representations, with the latter demonstrating place-cell-like responses when trained on a linear track environment.

Does the Mind Reflect the Mouth? Sensory Profiling and the Future

G Dijksterhuis — 2005-12-21T15:45:56-00:00

Critical Reviews in Food Science and Nutrition, Vol. 45, No. 7-8. (December 2005), pp. 527-534.

Feeding behavior of Aplysia: A model system for comparing cellular mechanisms of classical and operant conditioning

Douglas Baxter — 2008-06-24T06:11:19-00:00

Learn. Mem., Vol. 13, No. 6. (1 November 2006), pp. 669-680.

Feeding behavior of Aplysia provides an excellent model system for analyzing and comparing mechanisms underlying appetitive classical conditioning and reward operant conditioning. Behavioral protocols have been developed for both forms of associative learning, both of which increase the occurrence of biting following training. Because the neural circuitry that mediates the behavior is well characterized and amenable to detailed cellular analyses, substantial progress has been made toward a comparative analysis of the cellular mechanisms underlying these two forms of associative learning. Both forms of associative learning use the same reinforcement pathway (the esophageal nerve, En) and the same reinforcement transmitter (dopamine, DA). In addition, at least one cellular locus of plasticity (cell B51) is modified by both forms of associative learning. However, the two forms of associative learning have opposite effects on B51. Classical conditioning decreases the excitability of B51, whereas operant conditioning increases the excitability of B51. Thus, the approach of using two forms of associative learning to modify a single behavior, which is mediated by an analytically tractable neural circuit, is revealing similarities and differences in the mechanisms that underlie classical and operant conditioning. 10.1101/lm.339206

A comprehensive review of genetic association studies.

JN Hirschhorn — 2007-09-09T19:39:18-00:00

Genet Med, Vol. 4, No. 2. (r 2002), pp. 45-61.

Most common diseases are complex genetic traits, with multiple genetic and environmental components contributing to susceptibility. It has been proposed that common genetic variants, including single nucleotide polymorphisms (SNPs), influence susceptibility to common disease. This proposal has begun to be tested in numerous studies of association between genetic variation at these common DNA polymorphisms and variation in disease susceptibility. We have performed an extensive review of such association studies. We find that over 600 positive associations between common gene variants and disease have been reported; these associations, if correct, would have tremendous importance for the prevention, prediction, and treatment of most common diseases. However, most reported associations are not robust: of the 166 putative associations which have been studied three or more times, only 6 have been consistently replicated. Interestingly, of the remaining 160 associations, well over half were observed again one or more times. We discuss the possible reasons for this irreproducibility and suggest guidelines for performing and interpreting genetic association studies. In particular, we emphasize the need for caution in drawing conclusions from a single report of an association between a genetic variant and disease susceptibility.

Effects of scent and breadth on use of site-specific search on e-commerce Web sites

Michael Katz — 2006-10-04T15:13:39-00:00

ACM Trans. Comput.-Hum. Interact., Vol. 10, No. 3. (September 2003), pp. 198-220.

Crypt dynamics and colorectal cancer: advances in mathematical modelling

Van Leeuwen — 2006-05-01T03:22:19-00:00

Cell Proliferation, Vol. 39, No. 3. (June 2006), pp. 157-181.

Importance of Radiotherapy in the Outcome of Patients With Primary CNS Lymphoma: An Analysis of the CHOD/BVAM Regimen Followed by Two Different Radiotherapy Treatments

EM Bessell — 2008-05-24T10:18:30-00:00

J Clin Oncol, Vol. 20, No. 1. (1 January 2002), pp. 231-236.

PURPOSE: To assess the effect of a reduced dose of radiotherapy (RT) in patients with primary CNS lymphoma (PCNSL) responding to the cyclophosphamide, doxorubicin, vincristine, and dexamethasone (CHOD)/carmustine, vincristine, methotrexate, and cytarabine (BVAM) regimen. PATIENTS AND METHODS: Patients received one cycle of CHOD and two of BVAM. In the first trial, all 31 patients received 45-Gy whole-brain RT (CHOD/BVAM I). In the second, with 26 patients, RT dose was reduced to 30.6 Gy if there was a complete response (CR) after chemotherapy (CHOD/BVAM II). RESULTS: Age, performance status, and chemotherapy received were similar in both protocols. CR rate at the end of all treatment was 68% for CHOD/BVAM I and 77% and for CHOD/BVAM II. Treatment modality was the only predictor of relapse, with 3-year relapse risks of 29% and 70% for CHOD/BVAM I and II, respectively. This was specifically important in the 25 patients less than 60 years old (3-year relapse risk, 25% v 83%; P = .01). The 5-year overall survival (OS) was 36%. Age (< 60 v [>=] 60 years) was the only predictor for OS in the multivariate analysis (relative risk, 2.1; 95% confidence interval, 1.4 to 2.8). RT dose was the only predictor of OS in patients younger than 60 years old who achieved CR at the end of all treatment (3-year OS, 92% v 60% for patients receiving 45 or 30.6 Gy, respectively; P = .04). CONCLUSION: Reduction of the RT dose from 45 Gy to 30.6 Gy in patients younger than 60 years old with PCNSL who achieved CR resulted in an increased risk of relapse and lower OS. 10.1200/JCO.20.1.231

Genome-wide detection and characterization of positive selection in human populations

Pardis Sabeti — 2007-10-17T17:54:19-00:00

Nature, Vol. 449, No. 7164. (18 October 2007), pp. 913-918.

High yield production of graphene by liquid phase exfoliation of graphite

Y Hernandez — 2008-05-23T08:27:28-00:00

(19 May 2008)

Graphene is at the centre of nanotechnology research. In order to fully exploit its outstanding properties, a mass production method is necessary. Two main routes are possible: large-scale growth or large-scale exfoliation. Here, we demonstrate graphene dispersions with concentrations up to ~0.01 mg/ml by dispersion and exfoliation of graphite in organic solvents such as N-methyl-pyrrolidone. This occurs because the energy required to exfoliate graphene is balanced by the solvent-graphene interaction for solvents whose surface energy matches that of graphene. We confirm the presence of individual graphene sheets with yields of up to 12% by mass, using absorption spectroscopy, transmission electron microscopy and electron diffraction. The absence of defects or oxides is confirmed by X-ray photoelectron, infra-red and Raman spectroscopies. We can produce conductive, semi-transparent films and conductive composites. Solution processing of graphene opens up a whole range of potential large-scale applications from device or sensor fabrication to liquid phase chemistry.

An integrated theory of the mind.

JR Anderson — 2005-09-13T21:23:41-00:00

Psychol Rev, Vol. 111, No. 4. (October 2004), pp. 1036-1060.

Adaptive control of thought-rational (ACT-R; J. R. Anderson & C. Lebiere, 1998) has evolved into a theory that consists of multiple modules but also explains how these modules are integrated to produce coherent cognition. The perceptual-motor modules, the goal module, and the declarative memory module are presented as examples of specialized systems in ACT-R. These modules are associated with distinct cortical regions. These modules place chunks in buffers where they can be detected by a production system that responds to patterns of information in the buffers. At any point in time, a single production rule is selected to respond to the current pattern. Subsymbolic processes serve to guide the selection of rules to fire as well as the internal operations of some modules. Much of learning involves tuning of these subsymbolic processes. A number of simple and complex empirical examples are described to illustrate how these modules function singly and in concert.

Polytope Representations for Linear-Programming Decoding of Non-Binary Linear Codes

Vitaly Skachek — 2008-05-14T06:16:20-00:00

(17 Apr 2008)

In previous work, we demonstrated how decoding of a non-binary linear code could be formulated as a linear-programming problem. In this paper, we study different polytopes for use with linear-programming decoding, and show that for many classes of codes these polytopes yield a complexity advantage for decoding. These representations lead to polynomial-time decoders for a wide variety of classical non-binary linear codes.

The Secret (Unabridged, 4-CD Set)

Rhonda Byrne — 2008-05-13T23:46:29-00:00

(28 November 2006)

YOU HOLD IN YOUR HANDS A GREAT SECRET.It has been passed down through the ages, highly coveted, hidden, lost, stolen, and bought for vast sums of money. Fragments of this Great Secret have been found in the oral traditions, in literature, in religions and philosophies throughout the centuries. It has been understood by some of the most prominent people in history: Plato, Galileo, Beethoven, Edison, Carnegie, and Einstein, along with other renowned inventors, theologians, scientists, and great thinkers. For the first time, all the pieces of The Secret come together in an incredible revelation that will be life transforming for all who experience it.In this audiobook you will discover The Secret . . . and you will learn how to have, do, or be anything you want. You will learn how to use The Secret in every single area of your life. You will hear from modern-day teachers -- men and women who have used The Secret to achieve health, prosperity, relationships and happiness. They share their incredible stories of using The Secret to eradicate disease, acquire massive wealth, overcome obstacles, and achieve what many would regard as impossible. Through them, you will begin to understand the hidden, untapped power that is within you, and the true magnificence that awaits you in life.To experience the film version of The Secret visit www.thesecret.tv

Networks in leaf development.

ME Byrne — 2006-11-02T20:25:49-00:00

Curr Opin Plant Biol, Vol. 8, No. 1. (February 2005), pp. 59-66.

Shoots are characterized by indeterminate growth resulting from divisions of undifferentiated cells in the central region of the shoot apical meristem. These cells give rise to peripheral derivatives from which lateral organ initials are recruited. During initial stages of cell recruitment, the three-dimensional form of lateral organs is specified. Lateral organs such as leaves develop and differentiate along proximodistal (base-to-tip), dorsoventral (top-to bottom) and mediolateral (middle-to-margin) planes. Current findings are refining our knowledge of the genes and genetic interactions that regulate these early processes and are providing a picture of how these pathways may contribute to variation in leaf form.

Measurement of latent tracks in amorphous SiO2 using small angle X-ray scattering

P Kluth — 2008-05-09T13:56:04-00:00

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. In Press, Corrected Proof

In this paper we present preliminary yet promising results on the measurement of latent ion tracks in amorphous, 2 [mu]m thick SiO2 layers using small angle X-ray scattering (SAXS). The tracks were generated by ion irradiation with 89 MeV Au ions to fluences between 3 נ1010 and 3 נ1012 ions/cm2. Transmission SAXS measurements show distinct scattering from the irradiated SiO2 as compared to the unirradiated material. Analysis of the SAXS spectra using a cylindrical model suggests a core-shell like density distribution in the ion tracks with a lower density core and a higher density shell as compared to unirradiated material. The total track radius of ~48 Å is in very good agreement with previous experiments and calculations based on an inelastic thermal spike model.

Habitat structure: A fundamental concept and framework for urban soil ecology

Loren Byrne — 2008-05-08T03:41:27-00:00

Urban Ecosystems, Vol. 10, No. 3. (2007), pp. 255-274.

Abstract Habitat structure is defined as the composition and arrangement of physical matter at a location. Although habitat structure is the physical template underlying ecological patterns and processes, the concept is relatively unappreciated and underdeveloped in ecology. However, it provides a fundamental concept for urban ecology because human activities in urban ecosystems are often targeted toward management of habitat structure. In addition, the concept emphasizes the fine-scale, on-the-ground perspective needed in the study of urban soil ecology. To illustrate this, urban soil ecology research is summarized from the perspective of habitat structure effects. Among the key conclusions emerging from the literature review are: (1) habitat structure provides a unifying theme for multivariate research about urban soil ecology; (2) heterogeneous urban habitat structures influence soil ecological variables in different ways; (3) more research is needed to understand relationships among sociological variables, habitat structure patterns and urban soil ecology. To stimulate urban soil ecology research, a conceptual framework is presented to show the direct and indirect relationships among habitat structure and ecological variables. Because habitat structure serves as a physical link between sociocultural and ecological systems, it can be used as a focus for interdisciplinary and applied research (e.g., pest management) about the multiple, interactive effects of urbanization on the ecology of soils.

The relationship of emotional exhaustion to work attitudes, job performance, and organizational citizenship behaviors.

R Cropanzano — 2008-05-06T09:48:40-00:00

The Journal of applied psychology, Vol. 88, No. 1. (February 2003), pp. 160-169.

The authors investigated the negative consequences of emotional exhaustion for individual employees and their employers. On the basis of social exchange theory, the authors proposed that emotional exhaustion would predict job performance, 2 classes of organizational citizenship behavior, and turnover intentions. In addition, the authors posited that the relationship between emotional exhaustion and effective work behaviors would be mediated by organizational commitment. With only a few exceptions, the results of 2 field studies supported the authors' expectations. In addition, emotional exhaustion exerted an independent effect on these criterion variables beyond the impact of age, gender, and ethnicity.

Does primate motion perception depend on the magnocellular pathway?

WH Merigan — 2008-05-01T10:15:51-00:00

J. Neurosci., Vol. 11, No. 11. (1 November 1991), pp. 3422-3429.

Human Mesenchymal Stem Cells Differentiate to a Cardiomyocyte Phenotype in the Adult Murine Heart

Catalin Toma — 2008-04-24T14:28:30-00:00

Circulation, Vol. 105, No. 1. (1 January 2002), pp. 93-98.

Background-- Cellular cardiomyoplasty has been proposed as an alternative strategy for augmenting the function of diseased myocardium. We investigated the potential of human mesenchymal stem cells (hMSCs) from adult bone marrow to undergo myogenic differentiation once transplanted into the adult murine myocardium. Methods and Results-- A small bone marrow aspirate was taken from the iliac crest of healthy human volunteers, and hMSCs were isolated as previously described. The stem cells, labeled with lacZ, were injected into the left ventricle of CB17 SCID/beige adult mice. At 4 days after injection, none of the engrafted hMSCs expressed myogenic markers. A limited number of cells survived past 1 week and over time morphologically resembled the surrounding host cardiomyocytes. Immunohistochemistry revealed de novo expression of desmin, beta-myosin heavy chain, alpha-actinin, cardiac troponin T, and phospholamban at levels comparable to those of the host cardiomyocytes; sarcomeric organization of the contractile proteins was observed. In comparison, neither cardiac troponin T nor phospholamban was detected in the myotubes formed in vitro by MyoD-transduced hMSCs. Conclusions-- The purified hMSCs from adult bone marrow engrafted in the myocardium appeared to differentiate into cardiomyocytes. The persistence of the engrafted hMSCs and their in situ differentiation in the heart may represent the basis for using these adult stem cells for cellular cardiomyoplasty. 10.1161/hc0102.101442

Alternating minimization and Boltzmann machine learning

W Byrne — 2008-04-16T19:38:45-00:00

Neural Networks, IEEE Transactions on, Vol. 3, No. 4. (1992), pp. 612-620.

Training a Boltzmann machine with hidden units is appropriately treated in information geometry using the information divergence and the technique of alternating minimization. The resulting algorithm is shown to be closely related to gradient descent Boltzmann machine learning rules, and the close relationship of both to the EM algorithm is described. An iterative proportional fitting procedure for training machines without hidden units is described and incorporated into the alternating minimization algorithm

The tangled Web we wove: a taskonomy of WWW use

Michael Byrne — 2006-10-04T15:14:52-00:00

(1999), pp. 544-551.

Neuropsychological performance over time in people at high risk of developing schizophrenia and controls.

MC Whyte — 2008-03-27T17:09:14-00:00

Biol Psychiatry, Vol. 59, No. 8. (15 April 2006), pp. 730-739.

BACKGROUND: Neuropsychological assessments of relatives of schizophrenics have shown subtle impairments in verbal memory, executive and intellectual function, which are stable in those beyond the age of maximum risk for the disorder. We sought to: (1) determine baseline neurocognitive predictors of psychosis, and (2) compare performance over time between relatives within the age of maximum risk, and controls. METHODS: (1) and (2) were examined in 118 individuals at familial high risk of schizophrenia (HR) and 30 controls (C), using one-way analyses of variance (ANOVAs) and repeated measures analyses of covariance (ANCOVAs), controlling for intelligence quotient, time between and number of assessments, and correcting for multiple comparisons. RESULTS: HR who became ill (n = 13) performed nonsignificantly less well at baseline than HR who did not (n = 105) on a test of verbal learning (t(109) = 2.1, p = .03). Across assessments, C performed significantly better than the entire HR group on immediate (F(3,133) = 5.11, p = .002) and delayed (F(3,133) = 5.02, p = .002) story recall. There were no significant interactions of time by group. CONCLUSIONS: Results suggest greater verbal memory impairment in HR who go on to develop schizophrenia. Stable differences between groups over time suggest a trait deficit, which is relatively unaffected by the presence of psychotic symptoms and psychosis onset. Alternatively, small numbers may have precluded detection of group by time interactions.

Recognizing rhetoric in health care policy analysis

Russell — 2008-03-04T17:19:34-00:00

Journal of Health Services Research and Policy, Vol. 13, No. 1. (January 2008), pp. 40-46.

Viscoelastic study of the mechanical unfolding of a protein by AFM.

M Kawakami — 2008-03-09T04:11:21-00:00

Biophys J, Vol. 91, No. 2. (15 July 2006)

We have applied a dynamic force modulation technique to the mechanical unfolding of a homopolymer of immunoglobulin (Ig) domains from titin, (C47S C63S I27)5, [(I27)5] to determine the viscoelastic response of single protein molecules as a function of extension. Both the stiffness and the friction of the homopolymer system show a sudden decrease when a protein domain unfolds. The decrease in measured friction suggests that the system is dominated by the internal friction of the (I27)5 molecule and not solvent friction. In the stiffness-extension spectrum we detected an abrupt feature before each unfolding event, the amplitude of which decreased with each consecutive unfolding event. We propose that these features are a clear indication of the formation of the known unfolding intermediate of I27, which has been observed previously in constant velocity unfolding experiments. This simple force modulation AFM technique promises to be a very useful addition to constant velocity experiments providing detailed viscoelastic characterization of single molecules under extension.

The Yeast Gene Order Browser: Combining curated homology and syntenic context reveals gene fate in polyploid species

Kevin Byrne — 2008-03-07T13:46:16-00:00

Genome Res., Vol. 15, No. 10. (1 October 2005), pp. 1456-1461.

We developed the Yeast Gene Order Browser (YGOB; http://wolfe.gen.tcd.ie/ygob) to facilitate visual comparisons and computational analysis of synteny relationships in yeasts. The data presented in YGOB, currently covering seven species, are based on sets of homologous genes that have been intensively manually curated based on both sequence similarity and genomic context (synteny). We reconciled different laboratories' lists of paralogous Saccharomyces cerevisiae gene pairs formed by genome duplication (ohnologs), and present near-exhaustive lists of the ohnolog pairs retained in S. cerevisiae (551, including 22 previously unidentified), Saccharomyces castellii (599), and Candida glabrata (404). 10.1101/gr.3672305

In Search of a 'Good Mix': 'Race', Class, Gender and Practices of Mothering

Bridget Byrne — 2008-03-04T18:52:29-00:00

Sociology, Vol. 40, No. 6. (1 December 2006), pp. 1001-1017.

Drawing on interviews with white middle-class mothers, this article examines the ways in which mothering involves practices and identities which are classed, raced and gendered. In particular, it focuses on the construction and articulation of middle-classness with whiteness. The article examines the women's descriptions of how they constructed social networks as mothers, chose schools for their children and planned their after-school activities. It argues that these activities involved in being mothers and bringing up children can be understood as performative of race, class and gender.That is, practices of mothering are implicated in repeating and re-inscribing classed and raced discourses 10.1177/0038038506069841

Predicted Breeding Values for Nine Plant and Fruit Characteristics of 28 Peach Genotypes

VAB de Souza — 2008-03-03T21:48:07-00:00

Journal of the American Society for Horticultural Science, Vol. 125, No. 4. (1 July 2000), pp. 460-465.

Breeding values (BVs) for four plant (bloom date, fruit development period, fruit density, and blind node propensity) and five fruit (weight, blush, shape, soluble solids, and titratable acidity) traits of 28 peach [Prunus persica (L.) Batsch (Peach Group)] genotypes used as parents in the Texas A&M University peach breeding program were predicted using best linear unbiased prediction (BLUP). Data from seedlings of 108 families developed from 42 peach parents were analyzed by using a mixed linear model, with years treated as fixed and additive genotypes as random factors. The precision of the predictions was high for most parental genotypes, as indicated by the correlations (rTI) between predicted and true BVs and the standard error of the predictions (SEP). In most cases, the higher the number of progeny, the better the agreement between predicted and true BVs for that parent. Parents with observations from more than 30 seedlings had a rTI [≥] 0.90 and smaller SEPs. For all traits analyzed, the lowest precision (low rTI and high SEP) was observed for `Flordaking', whose predicted BVs was based only on pedigree information.

The relation of brain oscillations to attentional networks.

J Fan — 2007-06-10T05:17:39-00:00

J Neurosci, Vol. 27, No. 23. (6 June 2007), pp. 6197-6206.

Previous studies have suggested the relation of particular frequency bands such as theta (4-8 Hz), alpha (8-14 Hz), beta (14-30 Hz), or gamma (>30 Hz) to cognitive functions. However, there has been controversy over which bands are specifically related to attention. We used the attention network test to separate three anatomically defined brain networks that carry out the functions of alerting, orienting, and executive control of attention. High-density scalp electrical recording was performed to record synchronous oscillatory activity and power spectrum analyses based on functional magnetic resonance imaging constrained dipole modeling were conducted for each attentional network. We found that each attentional network has a distinct set of oscillations related to its activity. The alerting network showed a specific decrease in theta-, alpha-, and beta-band activity 200-450 ms after a warning signal. The orienting network showed an increase in gamma-band activity at approximately 200 ms after a spatial cue, indicating the location of a target. The executive control network revealed a complex pattern when a target was surrounded with incongruent flankers compared with congruent flankers. There was an early (<400 ms) increase in gamma-band activity, a later (>400 ms) decrease in beta- and low gamma-band activity after the target onset, and a decrease of all frequency bands before response followed by an increase after the response. These data demonstrate that attention is not related to any single frequency band but that each network has a distinct oscillatory activity and time course.

The Rational Imagination: How People Create Alternatives to Reality (Bradford Books)

Ruth Byrne — 2006-08-17T14:20:52-00:00

(01 July 2005)

The human imagination remains one of the last uncharted terrains of the mind. This accessible and original monograph explores a central aspect of the imagination, the creation of counterfactual alternatives to reality, and claims that imaginative thoughts are guided by the same principles that underlie rational thoughts. Research has shown that rational thought is more imaginative than cognitive scientists had supposed; in The Rational Imagination, Ruth Byrne argues that imaginative thought is more rational than scientists have imagined. People often create alternatives to reality and imagine how events might have turned out "if only" something had been different. Byrne explores the "fault lines" of reality, the aspects of reality that are more readily changed in imaginative thoughts. She finds that our tendencies to imagine alternatives to actions, controllable events, socially unacceptable actions, causal and enabling relations, and events that come last in a temporal sequence provide clues to the cognitive processes upon which the counterfactual imagination depends. The explanation of these processes, Byrne argues, rests on the idea that imaginative thought and rational thought have much in common.

Correction of the Mutation Responsible for Sickle Cell Anemia by an RNA-DNA Oligonucleotide

Allyson Cole-Strauss — 2008-02-11T00:44:12-00:00

Science, Vol. 273, No. 5280. (6 September 1996), pp. 1386-1389.

10.1126/science.273.5280.1386

A global analysis of genetic interactions in Caenorhabditis elegans

Alexandra Byrne — 2007-09-26T18:37:23-00:00

Journal of Biology, Vol. 6 (26 September 2007), 8.

NAL-NL1 procedure for fitting nonlinear hearing aids: characteristics and comparisons with other procedures.

D Byrne — 2008-01-28T16:08:42-00:00

J Am Acad Audiol, Vol. 12, No. 1. (January 2001), pp. 37-51.

A new procedure for fitting nonlinear hearing aids (National Acoustic Laboratories' nonlinear fitting procedure, version 1 [NAL-NL1]) is described. The rationale is to maximize speech intelligibility while constraining loudness to be normal or less. Speech intelligibility is predicted by the Speech Intelligibility Index (SII), which has been modified to account for the reduction in performance associated with increasing degrees of hearing loss, especially at high frequencies. Prescriptions are compared for the NAL-NL1, desired sensation level [input/output], FIG6, and a threshold version of the Independent Hearing Aid Fitting Forum procedures. For an average speech input level, the NAL-NL1 prescriptions are very similar to those of the well-established NAL-Revised, Profound procedure. Compared with the other procedures, NAL-NL1 prescribes less low-frequency gain for flat and upward sloping audiograms. It prescribes less high-frequency gain for steeply sloping high-frequency hearing losses. NAL-NL1 tends to prescribe less compression than the other procedures. All procedures differ considerably from one another for some audiograms.

An international comparison of long-term average speech spectra

Denis Byrne — 2008-01-25T21:44:55-00:00

The Journal of the Acoustical Society of America, Vol. 96, No. 4. (1994), pp. 2108-2120.

The long-term average speech spectrum (LTASS) and some dynamic characteristics of speech were determined for 12 languages: English (several dialects), Swedish, Danish, German, French (Canadian), Japanese, Cantonese, Mandarin, Russian, Welsh, Singhalese, and Vietnamese. The LTASS only was also measured for Arabic. Speech samples (18) were recorded, using standardized equipment and procedures, in 15 localities for (usually) ten male and ten female talkers. All analyses were conducted at the National Acoustic Laboratories, Sydney. The LTASS was similar for all languages although there were many statistically significant differences. Such differences were small and not always consistent for male and female samples of the same language. For one-third octave bands of speech, the maximum short-term rms level was 10 dB above the maximum long-term rms level, consistent across languages and frequency. A “universal” LTASS is suggested as being applicable, across languages, for many purposes including use in hearing aid prescription procedures and in the Articulation Index.

Issues in Recognition of Spanish-Accented Spontaneous English

Ayako Ikeno — 2008-01-25T04:22:55-00:00

We describe a recognition experiment and two analytic experiments on a database of strongly Hispanic-accented English. We show the crucial importance of training on the Hispanicaccented data for acoustic model performance, and describe the tendency of Spanish-accented speakers to use longer, and presumably less-reduced, schwa vowels than native-English speakers.

Profiles of adolescent stress: the development of the adolescent stress questionnaire (ASQ).

DG Byrne — 2008-01-23T20:52:25-00:00

J Adolesc, Vol. 30, No. 3. (June 2007), pp. 393-416.

The importance of stress in the understanding of adolescent health and well-being is widely documented. The measurement of adolescent stress has however been subjected to sufficient methodological and conceptual criticism in recent times to warrant a concerted re-evaluation of the exercise. This study sought information on the nature of adolescent stressors, building on a previous instrument developed by the first author to ask adolescents themselves to inform the development of a pool of new items reflecting stressor experience and to advise on the wording of these items to comprehensively assess that experience. This pool of items was then administered as a self-reported questionnaire to a large sample of school-age adolescents (N>1000) together with a scale to assess the intensity of distress arising from stressor occurrence. Principal components analysis of the questionnaire yielded 10 internally reliable dimensions of adolescent stress, the nature of which were consistent with the available literature on adolescent stressor experience. Scales constructed from this PCA related positively to measures of anxiety and depression, and negatively to a measure of self-esteem, suggesting that they were valid measures of adolescent stress. Test-retest reliability was good for all scales. The resultant Adolescent Stress Questionnaire (ASQ) is therefore suggested to have potential for the measurement of adolescent stress in both research and clinical contexts.