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2002

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Articles 2611 - 2640 of 3435

Full-Text Articles in Physical Sciences and Mathematics

N-Commutator Groups, A. A. Mehrvarz, K. Azizi Jan 2002

N-Commutator Groups, A. A. Mehrvarz, K. Azizi

Turkish Journal of Mathematics

A sufficient condition such that any element of G' (the commutator subgroup of G) can be represented as a product of n commutators, was studied in \cite{GAL62}. In this article we study a necessary and sufficient condition such that any element of G' can be represented as a product of n commutators, Let n be the smallest nature number such that any element of finite group G can be represented as a product of n commutators. A group G with this property will be called an n -commutator group, and n will be denoted by c(G) . Then \frac{\ln( G' …

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A Macwilliams Type Identity, İrfan Şi̇ap Jan 2002

A Macwilliams Type Identity, İrfan Şi̇ap

Turkish Journal of Mathematics

A MacWilliams identity for a \rho complete weight enumerator of linear spaces of matrices with entries from the ring F_q[u]/(u^r-a), where a \in F_q, endowed with a non-Hamming metric is proved.

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Thermal Protective Clothing And Cardiovascular Function, Alison L. Fogarty, Karen A. Armstrong, Christopher Gordon, Herb Groeller, Brian F. Woods, Jodie M. Stocks, Nigel A. S Taylor Jan 2002

Thermal Protective Clothing And Cardiovascular Function, Alison L. Fogarty, Karen A. Armstrong, Christopher Gordon, Herb Groeller, Brian F. Woods, Jodie M. Stocks, Nigel A. S Taylor

Faculty of Science - Papers (Archive)

While the primary purpose of thennal protective uniforms is to minimise heat loading from hostile working environments, such uniforms also add to the physiological load by increasing metabolic rate, and limiting evaporative heat dissipation (I). Before one can provide physiological specifications for the design of thennal protective garments, one requires a thorough understanding ofthe physiological effects of wearing such unifonns. However, research in this area is dominated by field studies, with few cardiovascular variables being investigated. These field studies, while important, often bypass clothing trials under controlled laboratory conditions. As a consequence, very little is known about the cardiac output, …

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Considerations For Capping Metal-Contaminated Sediments In Dynamic Estuarine Environments, Stuart L. Simpson, Ian D. Pryor, Ben R. Mewburn, Graeme E. Batley, Dianne F. Jolley Jan 2002

Considerations For Capping Metal-Contaminated Sediments In Dynamic Estuarine Environments, Stuart L. Simpson, Ian D. Pryor, Ben R. Mewburn, Graeme E. Batley, Dianne F. Jolley

Faculty of Science - Papers (Archive)

The effects of tides, bioturbating organisms and periods of anoxia on metal fluxes from contaminated harbour sediments in a shallow tidal estuarine bay were studied, together with capping technology options for the containment of metal contaminants. Zinc fluxes from the sediments were high, ranging from 10 to 89 mg Zn /m2/day. In the absence of capping, experiments in corer reactors showed that simulated tidal processes increased zinc fluxes 5- fold. Fluxes were also greater in the presence of sediment-dwelling organisms. If organisms were removed, and recolonising organisms later added, their bioturbation activities initially lowered zinc fluxes, but fluxes …

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Clusterin Is An Extracellular Chaperone That Specifically Interacts With Slowly Aggregating Proteins On Their Off-Folding Pathway, Stephen Poon, T. M. Treweek, Mark R. Wilson, Simon B. Easterbrook-Smith, John A. Carver Jan 2002

Clusterin Is An Extracellular Chaperone That Specifically Interacts With Slowly Aggregating Proteins On Their Off-Folding Pathway, Stephen Poon, T. M. Treweek, Mark R. Wilson, Simon B. Easterbrook-Smith, John A. Carver

Faculty of Science - Papers (Archive)

Clusterin is an extracellular mammalian chaperone protein which inhibits stress-induced precipitation of many different proteins. The conformational state(s) of proteins that interact with clusterin and the stage(s) along the folding and off-folding (precipitation-bound) pathways where this interaction occurs were previously unknown. We investigated this by examining the interactions of clusterin with different structural forms of α-lactalbumin, γ-crystallin and lysozyme. When assessed by ELISA and native gel electrophoresis, clusterin did not bind to various stable, intermediately folded states of α-lactalbumin nor to the native form of this protein, but did bind to and inhibit the slow precipitation of reduced α-lactalbumin. Reduction-induced …

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Synthesis Of (+/-)Epipentenomycin I And Iii, Weerachai Phutdhawong, Stephen G. Pyne, Apiwat Baramee, Duang Buddhasukh, Brian W. Skelton, Allan H. White Jan 2002

Synthesis Of (+/-)Epipentenomycin I And Iii, Weerachai Phutdhawong, Stephen G. Pyne, Apiwat Baramee, Duang Buddhasukh, Brian W. Skelton, Allan H. White

Faculty of Science - Papers (Archive)

A synthesis of (±) epipentenomycin I and III is reported from a regioselective epoxidation of racemic 3-hydroxy- and 3-acetoxy-2-methylene-4-cyclopentenone, respectively, with dimethyldioxirane followed by hydrolytic ring-opening of the resulting epoxide.

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Mildly Acidic Ph Activates The Extracellular Molecular Chaperone Clusterin, Stephen Poon, M. S. Rybchyn, S. B. Easterbrook-Smith, J. A. Carver, G. J. Pankhurst, Mark R. Wilson Jan 2002

Mildly Acidic Ph Activates The Extracellular Molecular Chaperone Clusterin, Stephen Poon, M. S. Rybchyn, S. B. Easterbrook-Smith, J. A. Carver, G. J. Pankhurst, Mark R. Wilson

Faculty of Science - Papers (Archive)

Many features of the chaperone action of clusterin are similar to those of the intracellular small heat shock proteins (sHSPs) which, like clusterin, exist in solution as heterogeneous aggregates. Increased temperature induces dissociation of some sHSP aggregates and an enhanced chaperone action, suggesting that a dissociated form is the active chaperone species. We recently reported that clusterin aggregates dissociate at mildly acidic pH. To further explore the similarities between clusterin and the sHSPs, we tested the effects of temperature and pH on the structure of clusterin and its chaperone action. Our results demonstrate that increased temperature does not induce dissociation …

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Was The Ad 1607 Coastal Flooding Event In The Severn Estuary And Bristol Channel (Uk) Due To A Tsunami?, Edward A. Bryant, S. K. Haslett Jan 2002

Was The Ad 1607 Coastal Flooding Event In The Severn Estuary And Bristol Channel (Uk) Due To A Tsunami?, Edward A. Bryant, S. K. Haslett

Faculty of Science - Papers (Archive)

Extensive coastal lowlands known as Levels border the Severn Estuary and Bristol Channel in southwest Britain. The Levels are the result of many years of salt marsh reclamation, apparently initiated during the Roman Period, through a programme of sea bank construction. The altitude of the Levels is typically between 5-6 m Ordnance Datum (OD), an altitude that is below the current Mean High Water Springs level in the Severn Estuary. Therefore, the Levels are vulnerable to flooding, not only from river sources, but also from the sea at times when sea banks are overtopped and/or breached. A number of significant …

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Identification And Distribution Of Masked And Hayden's Shrews (Genus Sorex) In Iowa, Howard P. Whidden, Alison W. Ray, John B. Bowles Jan 2002

Identification And Distribution Of Masked And Hayden's Shrews (Genus Sorex) In Iowa, Howard P. Whidden, Alison W. Ray, John B. Bowles

Journal of the Iowa Academy of Science: JIAS

Masked shrews (Sorex cinereus) and Hayden's shrews (S. haydeni) are both reported from Iowa, but the two species are difficult to tell apart and their relative distributions in Iowa have been unclear. We took 13 skull measurements and examined 2 qualitative features on more than 300 specimens of Sorex from Iowa. The vast majority of our specimens could be identified easily by cranial measurements, and more than half could be identified by the relative position of the maxillary plate. We found no evidence for intergradation between the two species. Masked shrews are present throughout most of Iowa, whereas Hayden's shrews …

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Back Cover Jan 2002

Back Cover

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

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Soybean Canopy Gap Influence On Velvetleaf Seed Production, Shawn R. Wright, Micheal D. K. Owen, Douglas D. Buhler Jan 2002

Soybean Canopy Gap Influence On Velvetleaf Seed Production, Shawn R. Wright, Micheal D. K. Owen, Douglas D. Buhler

Journal of the Iowa Academy of Science: JIAS

Gaps in the soybean row provide locations for velvetleaf (Abutilon theophrasti) plant growth. Gap width, and velvetleaf plant location within the gap, were investigated for effect on seed production. There was no significant difference in velvetleaf capsule production between plants that grew either centered in a gap or at the western end of a gap in east-west oriented soybean rows. Also, there was no difference in plant survival, emergence through the soybean canopy, flowering, locule number per capsule, or average seed weight of velvetleaf based on gap width. However, there was a difference in capsule production based on gap width. …

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Editorial Board & Iowa Academy Of Science Officers And Directors Jan 2002

Editorial Board & Iowa Academy Of Science Officers And Directors

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

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Cover - Table Of Contents Jan 2002

Cover - Table Of Contents

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

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Effects Of Cattle Grazing On Woodlands In Central Iowa, Cathy Mabry Jan 2002

Effects Of Cattle Grazing On Woodlands In Central Iowa, Cathy Mabry

Journal of the Iowa Academy of Science: JIAS

Iowa's forests have undergone a dramatic decline in area since settlement by Europeans. Most of the remaining forests have been degraded by an assortment of human impacts, with cattle grazing the most prominent among them. Using a matched pairs study designed to control for environmental differences among plots, I examined the impact of cattle grazing on the forest understory, canopy trees, and tree regeneration. There were distinct groups of understory species associated with ungrazed and grazed plots. Species associated with ungrazed plots were all native and tended to be perennial herbs with fleshy roots. Ungrazed plots also had species preferring …

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Science Safety Status In Iowa Schools, Gerlovich A. Jack, Rahul Parsa, Bruce Frana, Theresa Stiner Jan 2002

Science Safety Status In Iowa Schools, Gerlovich A. Jack, Rahul Parsa, Bruce Frana, Theresa Stiner

Journal of the Iowa Academy of Science: JIAS

Between May and December 2001, 574 Iowa science teachers participated in a statewide science safety project supported by financial assistance from the Iowa Department of Natural Resources. Part one of the project focused on assessing the status of safety in Iowa secondary science programs. Part two was to provide teachers with information, tools, and training to address the identified needs. Three safety concerns were identified: one was associated with the age of lab facilities and two were related to safety training of teachers.

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Awards And Recognition, Iowa Academy Of Science, 2002 Jan 2002

Awards And Recognition, Iowa Academy Of Science, 2002

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

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Editorial Board & Iowa Academy Of Science Officers And Directors Jan 2002

Editorial Board & Iowa Academy Of Science Officers And Directors

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

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A Proposed Undergraduate Bioinformatics Curriculum For Computer Scientists, Travis E. Doom, Michael L. Raymer, Dan E. Krane, Oscar Garcia Jan 2002

A Proposed Undergraduate Bioinformatics Curriculum For Computer Scientists, Travis E. Doom, Michael L. Raymer, Dan E. Krane, Oscar Garcia

Kno.e.sis Publications

Bioinformatics is a new and rapidly evolving discipline that has emerged from the fields of experimental molecular biology and biochemistry, and from the the artificial intelligence, database, and algorithms disciplines of computer science. Largely because of the inherently interdisciplinary nature of bioinformatics research, academia has been slow to respond to strong industry and government demands for trained scientists to develop and apply novel bioinformatics techniques to the rapidly-growing, freely-available repositories of genetic and proteomic data. While some institutions are responding to this demand by establishing graduate programs in bioinformatics, the entrance barriers for these programs are high, largely due to …

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Tuberculosis Models With Fast And Slow Dynamics: The Role Of Close And Casual Contacts, Baojun Song, Carlos Castillo-Chavez, Juan Pablo Aparicio Jan 2002

Tuberculosis Models With Fast And Slow Dynamics: The Role Of Close And Casual Contacts, Baojun Song, Carlos Castillo-Chavez, Juan Pablo Aparicio

Department of Applied Mathematics and Statistics Faculty Scholarship and Creative Works

Models that incorporate local and individual interactions are introduced in the context of the transmission dynamics of tuberculosis (TB). The multi-level contact structure implicitly assumes that individuals are at risk of infection from close contacts in generalized household (clusters) as well as from casual (random) contacts in the general population. Epidemiological time scales are used to reduce the dimensionality of the model and singular perturbation methods are used to corroborate the results of time-scale approximations. The concept and impact of optimal average cluster or generalized household size on TB dynamics is discussed. We also discuss the potential impact of our …

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Passing The Torch Of Wildlife And Fisheries Management: Comparing The Attitudes And Values Of Younger And Older Conservation Professionals, Robert M. Muth, Rodney R. Zwick, Martha E. Mather, John F. Organ Jan 2002

Passing The Torch Of Wildlife And Fisheries Management: Comparing The Attitudes And Values Of Younger And Older Conservation Professionals, Robert M. Muth, Rodney R. Zwick, Martha E. Mather, John F. Organ

United States Geological Survey: Staff Publications

Wildlife-related values in American society are undergoing considerable change. Within the last few decades, non-consumptive recreational use of wildlife has increased dramatically; groups that subscribe to animal protection values (ranging from animal welfare to animal rights to animal liberation) are exercising increasing influence over wildlife policy, and the ranks of people who practice wildlife rehabilitation have grown significantly. In this time of questioning and change, it should not be surprising that the attitudes and values of conservation professionals are in transition as well. Within many agencies and academic institutions, the traditional focus on game management (Geist et al. 2001) is …

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Photochemical Production Of Dissolved Inorganic Nitrogen And Primary Amines From Dissolved Organic Nitrogen In Waters Of Two Estuaries And Adjacent Surficial Groundwaters, Dj Koopmans, Da Bronk Jan 2002

Photochemical Production Of Dissolved Inorganic Nitrogen And Primary Amines From Dissolved Organic Nitrogen In Waters Of Two Estuaries And Adjacent Surficial Groundwaters, Dj Koopmans, Da Bronk

VIMS Articles

Recent studies have shown that in a number of humic-rich surface waters in North America, NH4+ is released when dissolved organic matter (DOM) is exposed to sunlight. However, photochemical NH4+ production has not been observed in all surface waters, and factors that contribute to it are not well understood. We hypothesized that the presence or absence of NH4+ photoproduction may be affected by the light exposure history of DOM, The present study was undertaken to determine whether DOM from surficial groundwaters, with minimal light exposure history, would produce labile nitrogen (N) photoproducts more consistently, In this study, estuarine surface waters …

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Photo Synthesis/Irradiance Relationships In The Ross Sea, Antarctica, And Their Control By Phytoplankton Assemblage Composition And Environmental Factors, C. M. Van Hilst, Walker O. Smith Jr. Jan 2002

Photo Synthesis/Irradiance Relationships In The Ross Sea, Antarctica, And Their Control By Phytoplankton Assemblage Composition And Environmental Factors, C. M. Van Hilst, Walker O. Smith Jr.

VIMS Articles

The photosynthetic parameters of natural phytoplankton assemblages from the Ross Sea, Antarctica, as well as unialgal cultures of the diatom Pseudonitzschia sp. and the colonial haptophyte Phaeocystis antarctica were investigated to determine if differential responses to irradiance could explain the distribution of phytoplankton in the Ross Sea. Field assemblages had photosynthetic responses that suggested acclimation to low irradiance levels, and the initial rate of photosynthesis per unit chlorophyll (a) and the theoretical maximum rate of production (p(max)(B)) averaged 0,083 mg C (mg chl a)(-1) h(-1) (mumol m(-2) s(-1))(-1) and 2,40 mg C (mg chl a)(-1) h(-1), respectively. An increase in …

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Stated Preference Methods For Environmental Management : Recreational Summer Flounder Angling In The Northeastern United States, Robert L. Hicks Jan 2002

Stated Preference Methods For Environmental Management : Recreational Summer Flounder Angling In The Northeastern United States, Robert L. Hicks

Reports

Environmental managers are becoming increasingly aware that environmental policies must be crafted in a way that incorporates the human dimensions of the ecosystem. Failure to incorporate stakeholder preferences into management measures can lead to policies that fail because people’s preferences, motivations, and behavior concerning their use of the environment were not properly considered even if defensible natural science approaches were incorporated in the management decision. In this paper, we present a new method for quantifying angler preferences for fisheries management. The method, called the Stated Preference Discrete Choice Technique (SPDC) (Louviere et. al) is a particular form of conjoint analysis, …

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A High Resolution Gravity Survey Of The Lake St. Martin Impact Structure, Manitoba, Canada, Christina Davids Jan 2002

A High Resolution Gravity Survey Of The Lake St. Martin Impact Structure, Manitoba, Canada, Christina Davids

Theses and Dissertations

There are roughly 160 known impact craters listed in the Cratering Database (Earth Impact Database, 2002) of these approximately 20% are buried structures. Geophysical methods of investigation are used to study buried impact structures and add to the growing knowledge base of crater properties. Approximately three to five craters are discovered each year, some of which may be identified through gravity anomalies. A high-resolution gravity survey of the Lake St. Martin impact structure, southern Manitoba, Canada, was conducted to further interpret the structure's gravity anomaly. Previous studies have suggested two different crater diameters for Lake St. Martin, one of 23-km …

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Derivation Of A Tasselled Cap Transformation Based On Landsat 7 At-Satellite Reflectance, C. Huang, Wylie L. Yang, Collin Homer, G. Zylstra Jan 2002

Derivation Of A Tasselled Cap Transformation Based On Landsat 7 At-Satellite Reflectance, C. Huang, Wylie L. Yang, Collin Homer, G. Zylstra

United States Geological Survey: Staff Publications

A new tasselled cap transformation based on Landsat 7 at-satellite reflectance was developed. This transformation is most appropriate for regional applications where atmospheric correction is not feasible. The brightness, greenness and wetness of the derived transformation collectively explained over 97% of the spectral variance of the individual scenes used in this study.

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Neutron Resonance Spectroscopy Of 104pd, 105pd, And 110pd, J D. Bowman, D A. Smith, Bret E. Crawford, T Haseyama, C A. Grossmann, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, N R. Roberson, S J. Seestrom, E I. Sharapov, Sharon L. Stephenson, V W. Yuan, A M. Sukhovoj Jan 2002

Neutron Resonance Spectroscopy Of 104pd, 105pd, And 110pd, J D. Bowman, D A. Smith, Bret E. Crawford, T Haseyama, C A. Grossmann, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, N R. Roberson, S J. Seestrom, E I. Sharapov, Sharon L. Stephenson, V W. Yuan, A M. Sukhovoj

Physics and Astronomy Faculty Publications

We have measured neutron resonances in the palladium isotopes 104, 105, and 110 for neutron energies from 1 to 2100 eV. Many new p-wave resonances have been observed. Their neutron widths and, in several cases, the radiative widths were measured. The average level spacings and the s-wave and p-wave neutron strength functions were determined. The time-of-flight method was used for both neutron total cross section measurements and total (n,γ) reaction yield measurements at the pulsed spallation neutron source of Los Alamos Neutron Science Center. Well established resonance spectroscopy for these isotopes is essential for the analysis of parity violation data …

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Analytically Continued Hypergeometric Expression Of The Incomplete Beta Function, Jack C. Straton Jan 2002

Analytically Continued Hypergeometric Expression Of The Incomplete Beta Function, Jack C. Straton

Physics Faculty Publications and Presentations

The Incomplete Beta Function is rewritten as a Hypergeometric Function that is the analytic continuation of the conventional form, a generalization of the finite series, which simpifies the Stieltjes transform of powers of a monomial divided by powers of a binomial.

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Indirect-Drive Noncryogenic Double-Shell Ignition Targets For The National Ignition Facility: Design And Analysis, Peter A. Amendt, J. D. Colvin, R. E. Tipton, D. E. Hinkel, M. J. Edwards, O. L. Landen, John D. Ramshaw, L. J. Suter, W. S. Varnum, R. G. Watt Jan 2002

Indirect-Drive Noncryogenic Double-Shell Ignition Targets For The National Ignition Facility: Design And Analysis, Peter A. Amendt, J. D. Colvin, R. E. Tipton, D. E. Hinkel, M. J. Edwards, O. L. Landen, John D. Ramshaw, L. J. Suter, W. S. Varnum, R. G. Watt

Physics Faculty Publications and Presentations

Analysis and design of indirect-drive National Ignition Facility double-shell targets with hohlraum temperatures of 200 eV and 250 eV are presented. The analysis of these targets includes the assessment of two-dimensional radiation asymmetry and nonlinear mix. Two-dimensional integrated hohlraum simulations indicate that the x-ray illumination can be adjusted to provide adequate symmetry control in hohlraums specially designed to have high laser-coupling efficiency [Suter et al., Phys. Plasmas 7, 2092 (2000)]. These simulations also reveal the need to diagnose and control localized 10?15 keV x-ray emission from the high-Z hohlraum wall because of strong absorption by the high-Z inner shell. Preliminary …

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Clinical Assessment Of The Quantitative Posturography System (Qps), Jacinta Browne, G. O'Hare, A. Finn, J. Colin Jan 2002

Clinical Assessment Of The Quantitative Posturography System (Qps), Jacinta Browne, G. O'Hare, A. Finn, J. Colin

Articles

The objectives of this study were to evaluate a novel design dynamic force platform the Quantitative Posturography System (QPS). The evaluation consisted of identifying the effects due to ageing and disease of the postural control system and also to examine the relationship between functional performance and postural sway. An AOVA design and Pearson-Product correlation design were used. Seventy healthy subjects, seven subjects with Parkinson’s disease and eight subjects with a history of falls took part in the study. It was found that the QPS was able to identify changes due to both the ageing process and disease on the postural …

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Benchmarking Java And .Net, J. Travis Schlist Jan 2002

Benchmarking Java And .Net, J. Travis Schlist

Capstone Research Projects

No abstract provided.

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