1,799 research outputs found
Parton, Leathel (Journalism) (n.d.) [handwritten; 3l.]
Teacher narrative from Leathel E. Parton, untitled, undated, circa 1945https://scholarlycommons.pacific.edu/cook-nisei/1166/thumbnail.jp
Boundary value problems of elasticity theory for plane domains with one-dimensional elastic reinforcements
This article is a translation of an article published in Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No 1, pp 103-114 Jan-Feb 1991.Many authors have examined problems related to the load transmission from an elastic rod to an elastic plane. It was assumed in the majority of investigationa that the stringer is a thin rectilinear rod transmitting only longitudinal forces while the rod contact with the plane is realized along a line. different modifications of sheet contact with a rectilinear tensile stringer considered as an inner stringer of finite length or as an infinite edge stringer were analyzed in [1, 2]. Problems about the reinforcement of holes in a plate by a thin rod of constant section that possesses bending and longitudinal stiffnesses were solved in [3]. The eccentricity of the connection between the shell middle surface and the rod was taken into account in [4] in a study of shells reinforced by thin curvilinear rods. Other models of the one-dimensional element connected to an elastic medium without taking account of its bending stiffness were analyzed in [5, 6]. Solutions of a number of problems with circular reinforcing elements are obtained in [7]. An isotropic finite or infinite, linearly elastic plate reinforced along part or all of the boundary and along certain internal lines by elastic curvilinear rods possessing variable longitudinal and bending stiffnesses, variable curvature and thickness, the eccentricity of the connection to the plate and with an arbitrary transverse section shape symmetric relative to the plate middle surface are studied in this paper. Boundary conditions on the line of plate contact with the inner or edge elastic rods are obtained for the reinforcement models generalizing [1, 2] by using the theory of elastic rods in the case of a plane state of stress. Existence and uniqueness theorems are proved for appropriate boundary value problems; the singularity of the stresses at angles and tips of the rods are proved. The relationships obtained carry over completely to the plane strain problem for an elastic cylinder reinforced by homogeneous cylindrical shells along the generator. Some of the results described here are represented in [8]
High energy scattering in 2+1 QCD
High energy scattering in 2+1 QCD is studied using the recent approach of
Verlinde and Verlinde. We calculate the color singlet part of the quark-quark
scattering exactly within this approach, and discuss some physical implication
of this result. We also demonstrate, by two independent methods, that
reggeization fails for the color singlet channel. We briefly comment on the
problem in 3+1 QCD.Comment: 20 pages, references adde
Primary production of the central grassland region of the United States
Includes bibliographical references (pages 44-45).Aboveground net primary production of grasslands is strongly influenced by the amount and distribution of annual precipitation. Analysis of data collected at 9500 sites throughout the central United States confirmed the overwhelming importance of water availability as a control of production. The regional spatial pattern of production reflected the east-west gradient in annual precipitation. Lowest values of aboveground net primary production were observed in the west and highest values in the east. This spatial pattern was shifted eastward during unfavorable years and westward during favorable years. Variability in production among years was maximum in northern New Mexico and southwestern Kansas and decreased towards the north and south. The regional pattern of production was largely accounted for by annual precipitation. Production at the site level was explained by annual precipitation, soil water-holding capacity, and an interaction term. Our results support the inverse texture hypothesis. When precipitation is 370 mm/yr
Visual neglect after right posterior cerebral artery infarction
This article has been made available through the Brunel Open Access Publishing Fund and is available from the specified link - Copyright © 2006 BMJ Publishing Group.Objectives: To investigate the characteristics and neuroanatomical correlates of visual neglect after right-sided posterior cerebral artery (PCA) infarction.Methods: 15 patients with acute PCA strokes were screened for the presence of neglect on a comprehensive battery of cognitive tests. Extra tests of visual perception were also carried out on six patients. To establish which areas were critically associated with neglect, the lesions of patients with and without neglect were compared.Results: Neglect of varying severity was documented in 8 patients. In addition, higher-order visual perception was impaired in 5 of the 6 patients. Neglect was critically associated with damage to an area of white matter in the occipital lobe corresponding to a white matter tract connecting the parahippocampal gyrus with the angular gyrus of the parietal lobe. Lesions of the thalamus or splenium of the corpus callosum did not appear necessary or sufficient to cause neglect, but may mediate its severity in these patients.Conclusions: PCA stroke can result in visual neglect. Interruption of the white matter fibres connecting the parahippocampal gyrus to the angular gyrus may be important in determining whether a patient will manifest neglect
Digital clocks: simple Boolean models can quantitatively describe circadian systems
Copyright © 2012 The Royal Society
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.The gene networks that comprise the circadian clock modulate biological function across a range of scales, from gene expression to performance and adaptive behaviour. The clock functions by generating endogenous rhythms that can be entrained to the external 24-h day-night cycle, enabling organisms to optimally time biochemical processes relative to dawn and dusk. In recent years, computational models based on differential equations have become useful tools for dissecting and quantifying the complex regulatory relationships underlying the clock's oscillatory dynamics. However, optimizing the large parameter sets characteristic of these models places intense demands on both computational and experimental resources, limiting the scope of in silico studies. Here, we develop an approach based on Boolean logic that dramatically reduces the parametrization, making the state and parameter spaces finite and tractable. We introduce efficient methods for fitting Boolean models to molecular data, successfully demonstrating their application to synthetic time courses generated by a number of established clock models, as well as experimental expression levels measured using luciferase imaging. Our results indicate that despite their relative simplicity, logic models can (i) simulate circadian oscillations with the correct, experimentally observed phase relationships among genes and (ii) flexibly entrain to light stimuli, reproducing the complex responses to variations in daylength generated by more detailed differential equation formulations. Our work also demonstrates that logic models have sufficient predictive power to identify optimal regulatory structures from experimental data. By presenting the first Boolean models of circadian circuits together with general techniques for their optimization, we hope to establish a new framework for the systematic modelling of more complex clocks, as well as other circuits with different qualitative dynamics. In particular, we anticipate that the ability of logic models to provide a computationally efficient representation of system behaviour could greatly facilitate the reverse-engineering of large-scale biochemical networks
Children, family and the state : revisiting public and private realms
The state is often viewed as part of the impersonal public sphere in opposition to the private family as a locus of warmth and intimacy. In recent years this modernist dichotomy has been challenged by theoretical and institutional trends which have altered the relationship between state and family. This paper explores changes to both elements of the dichotomy that challenge this relationship: a more fragmented family structure and more individualised and networked support for children. It will also examine two new elements that further disrupt any clear mapping between state/family and public/private dichotomies: the third party role of the child in family/state affairs and children's application of virtual technology that locates the private within new cultural and social spaces. The paper concludes by examining the rise of the 'individual child' hitherto hidden within the family/state dichotomy and the implications this has for intergenerational relations at personal and institutional levels
Simulation of the effects of photodecay on long-term litter decay using DayCent
Recent studies have found that solar ultraviolet (UV) radiation significantly shifts the mass loss and nitrogen dynamics of plant litter decomposition in semi-arid and arid ecosystems. In this study, we examined the role of photodegradation in litter decomposition by using the DayCent-UV biogeochemical model. DayCent-UV incorporated the following mechanisms related to UV radiation: (1) direct photolysis, (2) facilitation of microbial decomposition via production of labile materials, and (3) microbial inhibition effects. We also allowed maximum photodecay rate of the structural litter pool to vary with litter\u27s initial lignin fraction in the model. We calibrated DayCent-UV with observed ecosystem variables (e.g., volumetric soil water content, live biomass, actual evapotranspiration, and net ecosystem exchange), and validated the optimized model with Long-Term Intersite Decomposition Experiment (LIDET) observations of remaining carbon and nitrogen at three semi-arid sites in Western United States. DayCent-UV better simulated the observed linear carbon loss patterns and the persistent net nitrogen mineralization in the 10-year LIDET experiment at the three sites than the model without UV decomposition. In the DayCent-UV equilibrium model runs, UV decomposition increased aboveground and belowground plant production, surface net nitrogen mineralization, and surface litter nitrogen pool, but decreased surface litter carbon, soil net nitrogen mineralization, and mineral soil carbon and nitrogen. In addition, UV decomposition had minimal impacts on trace gas emissions and biotic decomposition rates. The model results suggest that the most important ecological impact of photodecay of surface litter in dry grasslands is to increase N mineralization from the surface litter (25%), and decay rates of the surface litter (15%) and decrease the organic soil carbon and nitrogen (5%)
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