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101.
Gertrud K. Nürnberg Lewis A. Molot Eavan O'Connor Hamdi Jarjanazi Jennifer Winter Joelle Young 《Journal of Great Lakes research》2013
Hypoxia and cyanobacterial blooms were extensive in Lake Simcoe during the 1980s and are still a problem to a lesser degree despite extensive nutrient load reduction from the catchment basin. The continuing signs of productivity indicate a potential internal phosphorus (P) source. Internal P load, as a redox-dependent release from bottom sediments, is hard to determine in a large, relatively shallow and partially unstratified lake such as Lake Simcoe. Of the lake's three major basins, only Kempenfelt Bay stratifies long enough to develop hypoxia in the stagnant summer hypolimnion. The following indications of sediment P release are available from historic data: 1) hypolimnetic hypoxia still occurs in Kempenfelt Bay although the hypoxic factor (number of days that an area equal to the bay's surface area is overlain by water of ≤ 2 mg/L dissolved oxygen, DO) has decreased substantially and significantly from 15.8 d/yr (1980–1994) to 4.0 d/yr (1995–2011); 2) hypoxic factors for other lake sections and at different DO levels also indicate widespread hypoxia; 3) concentrations of redox dependent metals, Fe and Mn, increase with depth; and 4) euphotic zone P and chlorophyll concentrations increase and water clarity decreases during fall turnover. Cyanobacterial blooms appear to occur in response to internal load as supported by occasional cyanobacteria counts. These indicators provide evidence that internal loading is likely occurring and affecting the water quality in Lake Simcoe. We expect that further monitoring, specific for internal load, will corroborate these results. 相似文献
102.
Methods and results are reported from a study of ships companies' exposure to low-frequency motions on three vessels of the Royal Navy. The aim of the study was to investigate relationships between deck accelerations and the incidence of problems such as difficulties with physical tasks, cognitive activities, motion sickness, and work effort. Ship motions were recorded continuously during sea patrols of 10-14 days. The data collected from the three vessels comprised 105 days of ship motions over 12 patrols, with 779 associated daily diaries from 78 participants. Problems most strongly associated with vessel motions were related to the difficulties with physical tasks. Some cognitive aspects of task performance and motion sickness were associated with vertical acceleration magnitudes, but the correlations were less strong than with physical tasks. Practitioner Summary: Little is known about the severity of ship motions that degrade physical and mental performance. The paper offers preliminary estimates of the motion threshold values below which the performance will not be degraded by motion. 相似文献
103.
R. M. Gordon (2005; see record 2005-08806-011) insists in his commentary on J. S. Wallerstein and J. M. Lewis's (2004; see record 2004-17367-002) work that the impact of divorce on children is fleeting, and he proposes, without supporting evidence, that the long-lasting psychological problems displayed by children of divorce in adolescence and adulthood reflect more the preexisting psychopathology of the parents and their traumatic parenting than any consequence of the disrupted marriage and the unhappy sequelae that so regularly constitute the postdivorce family. The authors' data, based on intensive periodic clinical study of these youngsters and their parents over several decades, indicate the contrary. No research has established that divorcing parents exhibit as a class more mental illness than parents in intact families. The authors' findings speak to the unmet needs of children of divorce for psychological help with their intimate relationships when they enter adulthood. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
104.
Xikui Li Zejia Liu R. W. Lewis 《International journal for numerical methods in engineering》2005,64(5):667-708
A mixed finite element for coupled thermo‐hydro‐mechanical (THM) analysis in unsaturated porous media is proposed. Displacements, strains, the net stresses for the solid phase; pressures, pressure gradients, Darcy velocities for pore water and pore air phases; temperature, temperature gradients, the total heat flux are interpolated as independent variables. The weak form of the governing equations of coupled THM problems in porous media within the element is given on the basis of the Hu–Washizu three‐filed variational principle. The proposed mixed finite element formulation is derived. The non‐linear version of the element formulation is further derived with particular consideration of the THM constitutive model for unsaturated porous media based on the CAP model. The return mapping algorithm for the integration of the rate constitutive equation, the consistent elasto‐plastic tangent modulus matrix and the element tangent stiffness matrix are developed. For geometrical non‐linearity, the co‐rotational formulation approach is utilized. Numerical results demonstrate the capability and the performance of the proposed element in modelling progressive failure characterized by strain localization and the softening behaviours caused by thermal and chemical effects. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
105.
The goal of this research was to operationalize the information technology infrastructure (ITI) concept by identifying its underlying dimensions and establishing a valid and reliable measure for the construct. In order to accomplish this task with the highest degree of certainty, two approaches were sequentially applied: exploratory factor analysis and confirmatory factor analysis. In evaluating the confirmatory factor model, a step-by-step process was employed, assessing unidimensionality, reliability, discriminant validity, and nomological validity. The dimensions of ITI were determined to be: Chief Information Officer, IT Planning, IT Security, Technology Integration, Advisory Committee, Enterprise Model, and Data Administration. Researchers may now make use of this validated ITI measure to conduct investigations of ITI and other organizational measures. Implications of the ITI measure with other organizational initiatives such as electronic commerce and knowledge management are explored. 相似文献
106.
It is argued that the behavior of dielectric particles as they shrink in size through micrometric to nanometric scales will be increasingly dominated by the properties of their interfaces with the environment. The various interatomic and intermolecular forces that determine the structure of these interfaces are reviewed with special emphasis on their electrical nature. A number of situations in which passive and dynamic dielectric properties are traceable to nanometric interfacial properties are considered. It is also demonstrated that such interfaces are nanometric electromechanical (NEM) systems which acting collectively also explain piezoelectricity in macroscopic systems. Interfaces are naturally nanometric entities and must have a major role in the future development of nanotechnology. Their ubiquitous employment in living systems is noted and comparison suggests synergistic opportunities. 相似文献
107.
A new method is described that enables the simultaneous detection of 6-3H thymidine incorporation and acid phosphatase activity in the same tissue section. Histochemically, naphthol AS B1 released by tissue based acid phosphatase activity from the substrate naphthyl AS B1 phosphoric acid is coupled with a range of diazonium salts to produce insoluble azo dyes. The azo dye tests result in a particulate localization of lysosomal acid phosphatase and also label diffuse sources associated with cell death. The tests selected permit the application of photographic emulsion without the necessity of an inert barrier layer to separate the emulsion from the histochemically treated cryosections. The localization of 6-3H thymidine incorporation and cell death in mouse thymus and duodenum is demonstrated and comparative counts estimating the distribution of 6-3H thymidine incorporation and hydrolase labelled cell death in the thymus are presented. Young mouse thymus (5 weeks) was found to contain 1·36 ± 0·12% dying cells and 6·78 ± 0·03% thymidine incorporating cells, whilst old mouse thymus (53 weeks) was found to contain 2·34 ± 0·6% dying cells and 5·29 ± 0·37% thymidine incorporating cells. 相似文献
108.
Ryosuke Saigusa Jenifer Vallejo Rishab Gulati Sujit Silas Armstrong Suthahar Vasantika Suryawanshi Ahmad Alimadadi Jeffrey Makings Christopher P. Durant Antoine Freuchet Payel Roy Yanal Ghosheh William Pandori Tanyaporn Pattarabanjird Fabrizio Drago Angela Taylor Coleen A. McNamara Avishai Shemesh Lewis L. Lanier Catherine C. Hedrick Klaus Ley 《International journal of molecular sciences》2022,23(17)
109.
E-Business management involves monitoring and controlling all forms of business transactions conducted over the Internet,
extranets, and related communications technologies and services. As such, it includes the management of networks, systems,
and software applications. E-Business management is beginning to depend increasingly on knowledge of the cooperative aspects
of partners in a business chain and the cooperative aspects of stake-holders in e-business operations. The study of cooperation
offers many opportunities to apply social network analyses to derive software solutions for the management of e-business.
This article provides a methodology and case study that recognises the dimension of cooperation among a multiplicity of organisations,
coined “Awareness-based Cooperative Management.” It is aimed towards the design or re-engineering of effective e-business
management systems, where the key concept involves the degree of awareness held by e-business stake-holders. Awareness is
defined in terms of stake-holder interactions and artefacts used in those interactions such as buyer specifications, requests
for proposals, offers, service level agreements, and the like. Since awareness is an indispensable, albeit an inherently vague
concept, we cast it and reason about it with the apparatus of fuzzy logic.
相似文献
Lundy LewisEmail: |
110.
Triangulation of planar regions with applications 总被引:24,自引:0,他引:24