Very Hard (very + hard)

Distribution by Scientific Domains


Selected Abstracts


The Sieve Model: An innovative process for identifying alternatives to custody evaluations

CONFLICT RESOLUTION QUARTERLY, Issue 3 2009
Robert B. Silver
This article reviews the development of the Sieve Model, conceived from dissatisfaction with adversarial processes that encouraged endless destructive fighting and depletion of financial and emotional family resources. Adversarial approaches discourage constructive problem solving and cooperation and are very hard on children. Rather than a piecemeal approach toward divorce, a systemic model was conceived. The Sieve Model is being implemented in the 20th Judicial Circuit of the State of Florida through differentiated case management, after a study revealed that protracted cases primarily involved disputes over children. Families are invited to use pertinent elements in an individualized fashion. Family law professionals are challenged to develop other solution-based efforts akin to mediation to assist families of divorce. The Sieve Model encourages participants to practice solving problems rather than creating them, decreasing divorce brutality and postjudgment conflicts. [source]


Effects of amendments of N, P, Fe on phytoextraction of Cd, Pb, Cu, and Zn in soil of Zhangshi by mustard, cabbage, and sugar beet

ENVIRONMENTAL TOXICOLOGY, Issue 6 2007
Lina Sun
Abstract Soil contaminated with Cd, Pb, Cu, and Zn in the Zhangshi irrigation area is very hard to be remediated. Phytoextraction is considered as an efficient method to remove these toxic metals from soil. In the present study, three vegetables including sugar beet (Beta vulgaris), mustard (Brassica juncea L.), and cabbage (Brassica oleracea L. var. capitata Linn.) were used to bioaccumulate heavy metals in soil through pots experiment for 90 days; and nutrient elements were applied to stimulate the phytoextraction of metals. Results of bioconcentration factors (BCF) and translocation factors (TF) from this study showed that these plants could phytoextract heavy metals, but the accumulation and translocation of metals differed with species of plants, categories of heavy metals, and some environmental conditions (e.g. nutrients). Meanwhile, the addition of nutrient elements, such as N, P, and Fe, could affect the phytoremediation of heavy metals via promoting the normal metabolism of vegetables or changing forms of metals. Results of this study could provide some available information for in-site bioremediation of soil from Zhangshi irrigation area. 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 565,571, 2007. [source]


Process Cost Comparison for Conventional and Near-Net-Shape Cermet Fabrication,

ADVANCED ENGINEERING MATERIALS, Issue 3 2010
Yuhong Xiong
Tungsten carbide,cobalt (WC,Co) is a widely used cermet that is generally fabricated into bulk parts via conventional powder metallurgy (P/M) methods. Because this material (and other cermets) is very hard and wear resistant, diamond grinding is generally required to fabricate complex parts. As an alternative, studies have shown the Laser Engineering Net Shaping (LENS) process to be a technically feasible method, allowing for fabrication of near-net-shape parts. The economic trade-offs, however, have not been previously characterized. In this work, technical cost modeling (TCM) is applied to compare the costs of fabricating WC,Co parts with the P/M process to those of the LENS process. Cost drivers are identified and sensitivity analysis is conducted. Results reveal that the uncertainty in functional unit has a significant effect on relative process costs, and the cost is sensitive to order size only if less than ten parts are produced. It is concluded that the LENS process is economically preferable if part size is small or part shape is complex. The P/M process is more suitable to produce large parts in simple shapes. [source]


Graph-theoretical identification of dissociation pathways on free energy landscapes of biomolecular interaction

JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 4 2010
Ling Wang
Abstract Biomolecular association and dissociation reactions take place on complicated interaction free energy landscapes that are still very hard to characterize computationally. For large enough distances, though, it often suffices to consider the six relative translational and rotational degrees of freedom of the two particles treated as rigid bodies. Here, we computed the six-dimensional free energy surface of a dimer of water-soluble alpha-helices by scanning these six degrees of freedom in about one million grid points. In each point, the relative free energy difference was computed as the sum of the polar and nonpolar solvation free energies of the helix dimer and of the intermolecular coulombic interaction energy. The Dijkstra graph algorithm was then applied to search for the lowest cost dissociation pathways based on a weighted, directed graph, where the vertices represent the grid points, the edges connect the grid points and their neighbors, and the weights are the reaction costs between adjacent pairs of grid points. As an example, the configuration of the bound state was chosen as the source node, and the eight corners of the translational cube were chosen as the destination nodes. With the strong electrostatic interaction of the two helices giving rise to a clearly funnel-shaped energy landscape, the eight lowest-energy cost pathways coming from different orientations converge into a well-defined pathway for association. We believe that the methodology presented here will prove useful for identifying low-energy association and dissociation pathways in future studies of complicated free energy landscapes for biomolecular interaction. 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 [source]


Unemployment variation over the business cycles: a comparison of forecasting models

JOURNAL OF FORECASTING, Issue 7 2004
Saeed Moshiri
Abstract Asymmetry has been well documented in the business cycle literature. The asymmetric business cycle suggests that major macroeconomic series, such as a country's unemployment rate, are non-linear and, therefore, the use of linear models to explain their behaviour and forecast their future values may not be appropriate. Many researchers have focused on providing evidence for the non-linearity in the unemployment series. Only recently have there been some developments in applying non-linear models to estimate and forecast unemployment rates. A major concern of non-linear modelling is the model specification problem; it is very hard to test all possible non-linear specifications, and to select the most appropriate specification for a particular model. Artificial neural network (ANN) models provide a solution to the difficulty of forecasting unemployment over the asymmetric business cycle. ANN models are non-linear, do not rely upon the classical regression assumptions, are capable of learning the structure of all kinds of patterns in a data set with a specified degree of accuracy, and can then use this structure to forecast future values of the data. In this paper, we apply two ANN models, a back-propagation model and a generalized regression neural network model to estimate and forecast post-war aggregate unemployment rates in the USA, Canada, UK, France and Japan. We compare the out-of-sample forecast results obtained by the ANN models with those obtained by several linear and non-linear times series models currently used in the literature. It is shown that the artificial neural network models are able to forecast the unemployment series as well as, and in some cases better than, the other univariate econometrics time series models in our test. Copyright 2004 John Wiley & Sons, Ltd. [source]


Optical filtering properties of inhomogeneous isotropic slab waveguides

LASER PHYSICS LETTERS, Issue 7 2004
A. Rostami
Abstract Inhomogeneous optical slab or channel wave-guides are basic alternative for realization of the passive and active devices and systems in the full-optical engineering domain. Usually, the exact treatment for obtaining the reflected and transmitted light is very hard and the numerical methods are used. In this paper, we will investigate the optical filtering properties of the exactly solvable large set of the inhomogeneous index of refraction profiles. We show that tuning of the inhomogeneous media length easily can control the bandwidth of our proposed filter. ( 2004 by ASTRO, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]


Ngongas and ecology: on having a worldview

OIKOS, Issue 1 2001
Joel S. Brown
Ngongas provide a metaphor for some of the opportunities and challenges facing the science of ecology and evolution. Ngongas, the traditional healers of the Shona culture, Zimbabwe, fail in the delivery of quality health by today's standards. Their outdated worldview makes most health related issues seem more complicated and more multi-factorial than when viewed through the worldviews of modern medicine. With the wrong worldview, one can work very hard, be very bright and dedicated, and still be ineffective. With the right worldview, one can work much less hard and still be extremely effective. As ecologists, we should be opinionated and possess clearly articulated worldviews for filtering and interpreting information. As ecologists we are also a bit like ngongas , we often fail to provide answers for society's ecological questions and problems, and we excuse ourselves with a belief that ecological systems are too complex and have too many factors. Unlike ngongas, this invites us to pay a lot of attention to promoting and assessing competing worldviews. We should be open-minded to the anomalies in our worldview and the successes of alternative viewpoints. As an admitted ecological ngonga, I discuss the worldview I use in my own research: the Optimization Research Program, a Darwinian research program that uses game theory to conceptualize and understand ecological systems. I use it illustrate how worldviews can synthesize disparate ideas. (I use kin selection and reciprocal altruism as examples.) I use it to show how new ideas and predictions can be generated. (I use root competition in plants and the possibility that increased crop yield may be forthcoming from knowledge of this game.) [source]


On the Origins of The American Journal of Economics and Sociology: Its Purposes and Objectives

AMERICAN JOURNAL OF ECONOMICS AND SOCIOLOGY, Issue 2 2001
Will Lissner
This essay, written with the help of his devoted wife, Mrs. Dorothy Burnham Lissner, was prepared at the request of the current editor of the AJES. This essay was written during the fall of 1999. On September 10, Mrs. Lissner informed me that, "The early history of the Journal is all done. . . . I hope it is satisfactory . . . Will and I worked very hard on it. Long hours. . . . so I decided to interview him and take down what he said or have him answer on tape. Then I put everything together on the computer, almost like an article. He [Will Lissner] has checked it and thinks it's perfect, that we can do no better" (correspendence of D. B. Lissner with L. Moss, 9/10/99). This is the last known writing of Will Lissner and summarizes his aims, goals, and ambitions for this Journal nearly six decades after its founding. Had Will had more time, this essay would have been the first of a series of reflections on this history of this Journal. [source]