魏晋南北朝的美学思想和盆景艺术

魏晋南北朝是中国古代动乱最多、人民生活最悲惨的时代。战争、动乱使汉王朝“独尊儒术”的旧思想体制大崩溃 ,导致魏晋南北朝时期的古代中国思想最解放、最自由。美学思想和精神的自由 ,酿就了艺术创造精神的勃发 ,因而新的艺术形式、艺术规律应运而生并相互融会贯通。此时的盆景艺术正是在绘画、园林、盆栽、赏石等艺术形式的影响下孕育了自己最初的表现形式和美学规律 ,因此可以说该时期是盆景发展史上的一个重要阶段     

THE EFFICACY AND EFFECTIVENESS OF MARITAL AND FAMILY THERAPY: A PERSPECTIVE FROM META-ANALYSIS

This article reviews the major findings from a multiproject meta-analysis of the effects of marital and family therapy (MFT). Across 163 randomized trials, MFT demonstrates moderate, statistically significant, and often clinically significant effects. No orientation is yet demonstrably superior to any other, nor is MFT superior to individual therapy. Cost effectiveness information is scant in these 163 studies, but supportive. Randomized experiments yield very different answers from nonrandomized experimental studies of the effects of MFT, calling into question whether we should mix the two in reviews. We have also found several new differences in the ways that marital therapy (MT) and family therapy (FT) studies are conducted, making them harder to compare. Finally, important questions still exist about whether any psychotherapy, including MFT, yet has sufficient information about how well research generalizes to everyday clinical practice.     

Estimating the Rayleigh distribution scale parameter from doubly censored samples—Some comments

In a recent paper in this journal, Lee, Kapadia and Brock (1980) developed maximum likelihood (ML) methods for estimating the scale parameter of the Rayleigh distribution from doubly censored samples. They reported convergence difficulties in attempting to solve numerically the nonlinear likelihood equation (LE). To mitigate these difficulties, they employed approximations to simplify the LE, but found that the solution of the resulting simplified equation can give rise to parameter estimates of erratic accuracy. We show that the use of approximations to simplify the LE is unnecessary. In fact, under suitable parametric transformation, the log-likelihood function is strictly concave, the ML estimate always exists, is unique and finite. Furthermore, the LE is easy to solve numerically. A numerical example is given to illustrate the computations involved.     

Construction and selection of tightened-normal-tightened sampling inspection scheme of type TNT-(n1, n2; c)

A table is presented for the construction and selection of tightened-normal-tightened sampling scheme of type TNT-(n1, n2;c). Efficiency of TNT-(n1, n2;c) scheme over conventional single and double sampling plans is discussed.     

Sociological computing: An opportunity missed?

Rapid advances in sociological computing are changing virtually every aspect of scholarly sociological work. These changes offer an opportunity for sociologists to improve the quality of their work and bring new insights and approaches to bear on important sociological problems. Nevertheless, sociologists display a profound ambivalence toward computer work by other sociologists. Left unchecked, this ambivalence threatens to turn sociological computing into an opportunity missed. Inadequate rewards, lack of training, and a general failure to understand the importance of computing in sociology threaten to stifle the development of quality soft-ware, push sociologists competent in computing into other fields, and jeopardize the quality of sociological scholarship. This article documents these ambivalent tendencies and proposes reasonable steps the discipline should take to assure that sociological computing does not become an opportunity missed.     

Tax-based research and data on non-profit organisations

Tax-exempt, non-profit organisations represent a significant and growing sector within the US economy. Between 1975 and 1990, assets of tax-exempt organisations increased in real terms by over 150 per cent while the revenue increased by over 227 per cent. This compares to a growth in real GDP of 52 per cent over the same period. A variety of tax policy issues on tax-exempt organisations and the non-profit sector can be addressed using several sources of data collected by the IRS from federal information and tax returns of exempt organisations. The Statistics of Income (SOI) Division, using sample data, conducts studies of many of the different components of the tax-exempt sector, including non-profit charitable organisations, organisations exempt under sections 501(c)(4)-(c)(9), private foundations and 4947(a) charitable trusts, and the unrelated business income of tax-exempt organisations. Income statement, balance sheet and other financial data, as well as a great amount of non-financial information, are collected in these SOI studies. The primary purposes of this article are: first, to document the role of the non-profit sector in the US economy and the evolving growth and change within the sector from the mid-1970s through to the present; and, second, to describe the ongoing SOI studies of tax-exempt organisations, the products and services available through SOI, and the future statistical plans at SOI for data collection and analysis of tax-exempt organisations and the non-profit sector.     

What to Do at Low Doses: A Bounding Approach for Economic Analysis

To quantify the health benefits of environmental policies, economists generally require estimates of the reduced probability of illness or death. For policies that reduce exposure to carcinogenic substances, these estimates traditionally have been obtained through the linear extrapolation of experimental dose-response data to low-exposure scenarios as described in the U.S. Environmental Protection Agency's Guidelines for Carcinogen Risk Assessment (1986). In response to evolving scientific knowledge, EPA proposed revisions to the guidelines in 1996. Under the proposed revisions, dose-response relationships would not be estimated for carcinogens thought to exhibit nonlinear modes of action. Such a change in cancer-risk assessment methods and outputs will likely have serious consequences for how benefit-cost analyses of policies aimed at reducing cancer risks are conducted. Any tendency for reduced quantification of effects in environmental risk assessments, such as those contemplated in the revisions to EPA's cancer-risk assessment guidelines, impedes the ability of economic analysts to respond to increasing calls for benefit-cost analysis. This article examines the implications for benefit-cost analysis of carcinogenic exposures of the proposed changes to the 1986 Guidelines and proposes an approach for bounding dose-response relationships when no biologically based models are available. In spite of the more limited quantitative information provided in a carcinogen risk assessment under the proposed revisions to the guidelines, we argue that reasonable bounds on dose-response relationships can be estimated for low-level exposures to nonlinear carcinogens. This approach yields estimates of reduced illness for use in a benefit-cost analysis while incorporating evidence of nonlinearities in the dose-response relationship. As an illustration, the bounding approach is applied to the case of chloroform exposure.