15 results on '"Hewitt JD"'
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2. The design and construction of the Wurrungwuri stone sculptures
- Author
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Australasian Structural Engineering Conference (2012 : Perth, W.A.), Hewitt, JD, Casson, JP, and Bull, SM
- Published
- 2012
Catalog
3. The design of special steelwork at no. 1 Bligh Street, Sydney
- Author
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Australasian Structural Engineering Conference (2012 : Perth, W.A.) and Hewitt, JD
- Published
- 2012
4. CsAr, CsXe, and RbXe B 2 Σ 1/2 + Interatomic Potentials Determined from Absorption Spectra and Calculations of Franck-Condon Factors for Free-Free Optical Transitions of Atomic Collision Pairs.
- Author
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Hewitt JD, Campbell C, Raymond KT, Park S, Desai KV, Mironov AE, and Eden JG
- Abstract
Interatomic potentials for the B
2 Σ1/2 + states of CsAr, CsXe, and RbXe have been determined through comparisons of experimental B ← X absorption spectra for alkali vapor-rare gas mixtures with calculations of the Franck-Condon factors (FCFs) associated with free-free transitions of thermal atomic pairs. Simulations of optical transitions of alkali-rare gas atomic pairs between the thermal and vibrational continua of the X2 Σ1/2 + and B2 Σ1/2 + states of the molecule, responsible for the blue satellites of the Cs and Rb D2 resonance lines in a rare gas background, require the incorporation of ground-state J values above ∼400 into the FCF calculations and proper normalization of the free-particle wave functions. Absorption spectra computed on the basis of several X and B state interatomic potentials available in the literature were found to be sensitive to the height of the B2 Σ1/2 + state barrier, as well as the X2 Σ1/2 + state repulsive wall contour and the location of the van der Waals minimum. Other spectral simulations entailed iterative modifications to a selected B2 Σ1/2 + interatomic potential, again coupled with comparison to experimental B ← X spectra. Comparisons of calculated spectra with experiment yield a CsXe B2 Σ1/2 + potential, for example, exhibiting a barrier height of 76 cm-1 at 5.2 Å and yet is nearly flat at smaller values of internuclear separation ( R ). The latter contrasts with previous theoretical calculations of VB ( R ) in the vicinity of the barrier maximum. For the CsAr molecule, the B2 Σ1/2 + barrier height was found to be 221 cm-1 , which is within 3% of the value determined from pseudopotential calculations incorporating the spin-orbit effect. Reproducing Cs-rare gas experimental absorption spectra also requires the existence of a broad, shallow potential well lying beyond the B2 Σ1/2 + barrier that, for CsAr, has a dissociation energy ( De ∼ 24 cm-1 ) a factor of 3 larger than values predicted by theory. Similar results are obtained for the RbXe and CsXe complexes. more...- Published
- 2023
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5. Spin Polarization of Rb and Cs np ^{2}P_{3/2} (n=5, 6) Atoms by Circularly Polarized Photoexcitation of a Transient Diatomic Molecule.
- Author
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Mironov AE, Hewitt JD, and Eden JG
- Abstract
We report the selective population of Rb or Cs np ^{2}P_{3/2} (n=5, 6; F=4, 5) hyperfine states by the photodissociation of a transient, alkali-rare gas diatomic molecule. Circularly polarized (σ^{-}), amplified spontaneous emission (ASE) on the D_{2} line of Rb or Cs (780.0 and 852.1 nm, respectively) is generated when Rb-Xe or Cs-Xe ground state collision pairs are photoexcited by a σ^{+}-polarized optical field having a wavelength within the D_{2} blue satellite continuum, associated with the B^{2}Σ_{1/2}^{+}←X^{2}Σ_{1/2}^{+} (free←free) transition of the diatomic molecule. The degree of spin polarization of Cs (6p ^{2}P_{3/2}), specifically, is found to be dependent on the interatomic distance (R) at which the excited complex is born, a result attributed to the structure of the B^{2}Σ_{1/2}^{+} state. For Cs-Xe atomic pairs, tuning the wavelength of the optical field from 843 to 848 nm varies the degree of circular polarization of the ASE from 63% to almost unity because of the perturbation, in the 5≤R≤6 Å interval, of the ^{2}Σ_{1/2}^{+} potential by a dσ molecular orbital associated with a higher ^{2}Λ electronic state. Monitoring only the Cs 6p ^{2}P_{3/2} spin polarization reveals a previously unobserved interaction of CsXe (B^{2}Σ_{1/2}^{+}) with the lowest vibrational levels of a ^{2}Λ state derived from Cs (5d)+Xe. By inserting a molecular intermediate into the alkali atom excitation mechanism, these experiments realize electronic spin polarization through populating no more than two np ^{2}P_{3/2} hyperfine states, and demonstrate a sensitive spectroscopic probe of R-dependent state-state interactions and their impact on interatomic potentials. more...
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- 2017
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6. Tunable ring laser with internal injection seeding and an optically-driven photonic crystal reflector.
- Author
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Zheng J, Ge C, Wagner CJ, Lu M, Cunningham BT, Hewitt JD, and Eden JG
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- Computer-Aided Design, Crystallization, Equipment Design, Equipment Failure Analysis, Photons, Amplifiers, Electronic, Lasers, Semiconductors
- Abstract
Continuous tuning over a 1.6 THz region in the near-infrared (842.5-848.6 nm) has been achieved with a hybrid ring/external cavity laser having a single, optically-driven grating reflector and gain provided by an injection-seeded semiconductor amplifier. Driven at 532 nm and incorporating a photonic crystal with an azobenzene overlayer, the reflector has a peak reflectivity of ~80% and tunes at the rate of 0.024 nm per mW of incident green power. In a departure from conventional ring or external cavity lasers, the frequency selectivity for this system is provided by the passband of the tunable photonic crystal reflector and line narrowing in a high gain amplifier. Sub - 0.1 nm linewidths and amplifier extraction efficiencies above 97% are observed with the reflector tuned to 842.5 nm. more...
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- 2012
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7. Health-related quality of life measures in routine clinical care: can FACT-fatigue help to assess the management of fatigue in cancer patients?
- Author
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Santana MJ, Au HJ, Dharma-Wardene M, Hewitt JD, Dupere D, Hanson J, Ghosh S, and Feeny D
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- Adult, Aged, Female, Humans, Male, Middle Aged, Neoplasms complications, Psychological Tests, Qualitative Research, Surveys and Questionnaires, Adaptation, Psychological, Fatigue psychology, Neoplasms psychology, Psychometrics, Quality of Life psychology
- Abstract
Objectives: Fatigue is the most common symptom reported by cancer patients. The inclusion of health-related quality of life (HRQL) measures in routine clinical care of cancer patients may improve the management of fatigue. The primary objective of this study is to provide evidence on the magnitude of change in fatigue subscale scores using the Functional Assessment of Cancer Therapy-Fatigue (FACT-F) that is clinically important., Methods: Consecutive patients with advanced primary lung cancer attending a Canadian tertiary care cancer and, prior to undergoing palliative chemotherapy, were enrolled in the study. Patients completed a battery of questionnaires [FACT-F, Qualitative Patients Self-report of Fatigue Level (QPSRF)] at baseline, follow-up and 2 weeks after their final cycle of chemotherapy. Clinicians assessed the patients using the Eastern Cooperative Oncology Group (ECOG) Performance Status Scale at baseline and each follow-up visit. FACT-F change scores were computed as the mean change in score (end of study score minus baseline score)., Results: A total of 43 patients with mean age of 59 years were enrolled in the study. Results revealed a mean change in FACT-F subscale score of 5.0 (SE 1.06) for those who rated themselves as more tired, 1.28 (SE 1.00) for those who rated themselves as the same (no change), and -1.52 (SE 0.84) for those patients who rated themselves as less tired., Conclusions: We provide evidence on the magnitude of change in FACT-F score that is associated with the perception by patients of improvement in fatigue and magnitude of change in score that is associated with worsening in fatigue. more...
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- 2009
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8. The effect of intermittent pneumatic compression on fracture healing.
- Author
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Hewitt JD, Harrelson JM, Dailiana Z, Guilak F, and Fink C
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- Absorptiometry, Photon, Animals, Biomechanical Phenomena, Bone Density, Bony Callus diagnostic imaging, Bony Callus pathology, Bony Callus physiopathology, Disease Models, Animal, Dogs, Male, Osteotomy, Radius Fractures diagnosis, Radius Fractures physiopathology, Fracture Healing, Intermittent Pneumatic Compression Devices, Radius Fractures therapy
- Abstract
Objectives: Continuously increased venous pressure has been shown to enhance bone growth, stimulate fracture healing, and prevent bone loss, but also causes soft-tissue breakdown as a result of chronic edema. This study was designed to test the hypothesis that intermittently increased venous pressure improves fracture healing without injuring soft tissue., Design: An ostectomy was created in the right radius of 30 skeletally mature male beagles. On postoperative day 7, a pneumatic cuff was placed around the forelimb of each dog. In experimental animals (n = 13), the cuff compressed for 5 minutes followed by no compression for 2.5 minutes. This cycle was repeated 100 times per day for 8 weeks. Control animals (n = 15) wore a nonfunctional cuff. Fracture healing was assessed with dual-energy x-ray absorptiometry, histologic analysis, and biomechanical testing., Results: No soft-tissue complications were noted. Bone mineral content at the ostectomy increased significantly more in the experimental group than in the control group (P < 0.05). Histology revealed that the bone defects in the experimental group were significantly more healed than those in the control group (P < 0.005). No differences were noted between groups in the biomechanical properties of the healing bones., Conclusions: Intermittently increased venous pressure proximal to a bone defect seems to enhance the formation of new bone without soft-tissue complications. These findings can potentially be applied to the clinical treatment of "difficult to heal" fractures. Further work is necessary to determine the most effective ratio of the presence and absence of pneumatic compression. more...
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- 2005
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9. On-the-fly fluorescence lifetime detection of humic substances in capillary electrophoresis.
- Author
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Hewitt JD and McGown LB
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- Reproducibility of Results, Sensitivity and Specificity, Benzopyrans analysis, Electrophoresis, Capillary methods, Humic Substances analysis, Soil analysis, Spectrometry, Fluorescence methods
- Abstract
On-the-fly fluorescence lifetime detection was investigated as a tool for studying humic substances in capillary zone electrophoresis (CZE). Humic substances are complex, heterogeneous mixtures of natural products that tend to migrate in a single, broad CZE peak. The intrinsic fluorescence lifetime of five humic substances from the International Humic Substances Society (IHSS) was monitored using excitation at 488 or 364 nm to produce intensity-lifetime electropherograms for each of the substances. Each frequency-domain lifetime measurement, collected at subsecond intervals during the CZE run, contains the equivalent of a complete decay profile. Lifetime analysis of each decay profile was used to construct a lifetime-resolved electropherogram for each lifetime component, from which the variation in relative intensity contributions of each lifetime across the broad CZE peak could be determined. Absorption spectra, fluorescence excitation-emission spectra, and lifetime profiles of batch solutions of the samples were determined as well. It was found that, whereas absorption and fluorescence spectral characteristics tended to discriminate between humic acids and fulvic acids, the batch solution lifetime profiles discriminated instead between samples from different sources, regardless of fraction. On-the-fly lifetime detection provided a more detailed view of the fluorescence decay of the samples, including greater resolution of lifetimes for two of the fulvic acids and greater discrimination among samples based on lifetime profiles across the CZE peaks. more...
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- 2003
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10. The mechanical properties of the human hip capsule ligaments.
- Author
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Hewitt JD, Glisson RR, Guilak F, and Vail TP
- Subjects
- Aged, Aged, 80 and over, Aging physiology, Analysis of Variance, Biomechanical Phenomena, Cadaver, Female, Humans, Male, Middle Aged, Stress, Mechanical, Hip Joint physiology, Joint Capsule physiology, Ligaments, Articular physiology
- Abstract
The human hip capsule is adapted to facilitate upright posture, joint stability, and ambulation, yet it routinely is excised in hip surgery without a full understanding of its mechanical contributions. The objective of this study was to provide information about the mechanical properties of the ligaments that form the hip capsule. Cadaver bone-ligament-bone specimens of the iliofemoral, ischiofemoral, and femoral arcuate ligaments were tested to failure in tension. The hip capsule was found to be an inhomogeneous structure and should be recognized as being composed of discrete constituent ligaments. The anterior ligaments, consisting of the 2 arms of the iliofemoral ligament, were much stronger than the posterior ischiofemoral ligament, withstanding greater force at failure and exhibiting greater stiffness. Knowledge of the anatomy and mechanical properties of the capsule may help the hip surgeon choose an appropriate surgical approach or repair strategy. more...
- Published
- 2002
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11. Mendelian factors underlying quantitative traits in tomato: comparison across species, generations, and environments.
- Author
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Paterson AH, Damon S, Hewitt JD, Zamir D, Rabinowitch HD, Lincoln SE, Lander ES, and Tanksley SD
- Subjects
- Biological Evolution, Breeding, Chromosome Mapping, Crosses, Genetic, Environment, Fruit genetics, Fruit metabolism, Genetic Markers genetics, Genotype, Hydrogen-Ion Concentration, Phenotype, Polymorphism, Restriction Fragment Length, Recombination, Genetic, Species Specificity, Genetic Variation genetics, Plants genetics
- Abstract
As part of ongoing studies regarding the genetic basis of quantitative variation in phenotype, we have determined the chromosomal locations of quantitative trait loci (QTLs) affecting fruit size, soluble solids concentration, and pH, in a cross between the domestic tomato (Lycopersicon esculentum Mill.) and a closely-related wild species, L. cheesmanii. Using a RFLP map of the tomato genome, we compared the inheritance patterns of polymorphisms in 350 F2 individuals with phenotypes scored in three different ways: (1) from the F2 progeny themselves, grown near Davis, California; (2) from F3 families obtained by selfing each F2 individual, grown near Gilroy, California (F3-CA); and (3) from equivalent F3 families grown near Rehovot, Israel (F3-IS). Maximum likelihood methods were used to estimate the approximate chromosomal locations, phenotypic effects (both additive effects and dominance deviations), and gene action of QTLs underlying phenotypic variation in each of these three environments. A total of 29 putative QTLs were detected in the three environments. These QTLs were distributed over 11 of the 12 chromosomes, accounted for 4.7-42.0% of the phenotypic variance in a trait, and showed different types of gene action. Among these 29 QTLs, 4 were detected in all three environments, 10 in two environments, and 15 in only a single environment. The two California environments were most similar, sharing 11/25 (44%) QTLs, while the Israel environment was quite different, sharing 7/20 (35%) and 5/26 (19%) QTLs with the respective California environments. One major goal of QTL mapping is to predict, with maximum accuracy, which individuals will produce progeny showing particular phenotypes. Traditionally, the phenotype of an individual alone has been used to predict the phenotype of its progeny. Our results suggested that, for a trait with low heritability (soluble solids), the phenotype of F3 progeny could be predicted more accurately from the genotype of the F2 parent at QTLs than from the phenotype of the F2 individual. For a trait with intermediate heritability (fruit pH), QTL genotype and observed phenotype were about equally effective at predicting progeny phenotype. For a trait with high heritability (mass per fruit), knowing the QTL genotype of an individual added little if any predictive value, to simply knowing the phenotype. The QTLs mapped in the L. esculentum X L. cheesmanii F2 appear to be at similar locations to many of those mapped in a previous cross with a different wild tomato (L. chmielewskii).(ABSTRACT TRUNCATED AT 400 WORDS) more...
- Published
- 1991
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12. Crime and mental illness in Middletown, 1870-1910: a study in social control.
- Author
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Hoover DW, Hewitt JD, and Kirchner J
- Subjects
- History, Modern 1601-, United States, Mental Disorders history
- Published
- 1983
13. Resolution of quantitative traits into Mendelian factors by using a complete linkage map of restriction fragment length polymorphisms.
- Author
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Paterson AH, Lander ES, Hewitt JD, Peterson S, Lincoln SE, and Tanksley SD
- Subjects
- Gene Frequency, Genetic Linkage, Genetic Markers, Plants genetics, Chromosome Mapping methods, Genes, Polymorphism, Genetic, Polymorphism, Restriction Fragment Length
- Abstract
The conflict between the Mendelian theory of particulate inheritance and the observation of continuous variation for most traits in nature was resolved in the early 1900s by the concept that quantitative traits can result from segregation of multiple genes, modified by environmental effects. Although pioneering experiments showed that linkage could occasionally be detected to such quantitative trait loci (QTLs), accurate and systematic mapping of QTLs has not been possible because the inheritance of an entire genome could not be studied with genetic markers. The use of restriction fragment length polymorphisms (RFLPs) has made such investigations possible, at least in principle. Here, we report the first use of a complete RFLP linkage map to resolve quantitative traits into discrete Mendelian factors, in an interspecific back-cross of tomato. Applying new analytical methods, we mapped at least six QTLs controlling fruit mass, four QTLs for the concentration of soluble solids and five QTLs for fruit pH. This approach is broadly applicable to the genetic dissection of quantitative inheritance of physiological, morphological and behavioural traits in any higher plant or animal. more...
- Published
- 1988
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14. Sink Metabolism in Tomato Fruit : III. Analysis of Carbohydrate Assimilation in a Wild Species.
- Author
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Yelle S, Hewitt JD, Robinson NL, Damon S, and Bennett AB
- Abstract
Carbohydrate composition and key enzymes involved in carbohydrate metabolism were assayed throughout development of Lycopersicon esculentum and L. chmielewskii fruit. Translocation and assimilation of asymmetric sucrose and total soluble solids content was also determined in both species. The data showed that L. chmielewskii accumulated less starch than L. esculentum, and this was related to a lower level of ADPglucose pyrophosphorylase and a higher level of phosphorylase in L. chmielewskii. L. chmielewskii accumulated sucrose throughout fruit development rather than glucose and fructose which were accumulated by L. esculentum. A low level of invertase and nondetectable levels of sucrose synthase were associated with the high level of sucrose in L. chmielewskii. Translocation and assimilation of asymmetrically labeled sucrose indicated that sucrose accumulated in L. chmielewskii fruit was imported and stored directly in the fruit without intervening metabolism along the translocation path. In contrast, the relatively low level of radioactive sucrose found in L. esculentum fruit appeared to arise from hydrolysis and resynthesis of sucrose. The possible relationship between the level of soluble solids and differences in carbohydrate metabolism in sink tissue of the two species is discussed. more...
- Published
- 1988
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15. Sink metabolism in tomato fruit : I. Developmental changes in carbohydrate metabolizing enzymes.
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Robinson NL, Hewitt JD, and Bennett AB
- Abstract
In developing tomato (Lycopersicon esculentum Mill.) fruit, starch levels reach a peak early in development with soluble sugars (hexoses) gradually increasing in concert with starch degradation. To determine the enzymic basis of this transient partitioning of carbon to starch, the activities of key carbohydrate-metabolizing enzymes were investigated in extracts from developing fruits of three varieties (cv VF145-7879, cv LA1563, and cv UC82B), differing in final soluble sugar accumulation. Of the enzymes analyzed, ADPglucose pyrophosphorylase and sucrose synthase levels were temporally correlated with the transient accumulation of starch, having highest activities in cv LA1563, the high soluble sugar accumulator. Of the starch-degrading enzymes, phosphorylase levels were fivefold higher than those of amylase, and these activities did not increase during the period of starch degradation. Fiften percent of the amylase activity and 45 to 60% of the phosphorylase activity was localized in the chloroplast in cv VF145-7879. These results suggest that starch degradation in tomato fruit is predominantly phosphorolytic. The results suggest that starch biosynthetic capacity, as determined by levels of ADPglucose pyrophosphorylase rather than starch degradative capacity, regulate the transient accumulation of starch that occurs early in tomato fruit development. The results also suggest that ADPglucose pyrophosphorylase and sucrose synthase levels correlated positively with soluble sugar accumulation in the three varieties examined. more...
- Published
- 1988
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