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1.
Abstract. This paper presents methods to analyze convergence in cross‐sectional data collected over time using distribution free statistics that are not sensitive to the magnitudes involved. Measures of concordance and discordance are employed in the empirical analysis of real personal income per capita for 48 U.S. States over the period 1929–2002. Although most States are converging with each other, some are converging faster than others. The methods used have the flexibility to focus on specific characteristics such as convergence in absolute differences or convergence in the ratio of rewards. The methods may also be used to consider convergence without switching and additionally be applied to other features such as the percentiles of the distributions.  相似文献   

2.
过渡金属离子与有机物对钢铁的缓蚀协同效应   总被引:1,自引:0,他引:1  
从过渡金属离子的特点、过渡金属离子对钢铁的缓释作用机理、及其与有机物对钢铁的缓释协同等方面,较全面地综述了过渡金属离子与有机物缓蚀体系应用于钢铁的研究现状,并结合铁质文物保护技术要求,提出了模拟制作铁质文物试片,选择合适的过渡金属离子与有机物,借鉴现代钢铁缓释剂研究的分析技术,开展铁质文物保护研究课题的技术路线.  相似文献   

3.
宋代馆阁藏书在品种数量、藏书内容、藏书的方式方法、藏书的利用等方面已远远超过以往任何时代,本文主要论述其独特之处。  相似文献   

4.
The outcome of over fifteen years research on large urban assemblages from the Australian cities of Sydney and Melbourne is discussed in terms of approaches to the archaeology of the modern city as they have evolved over the period. To better understand the archaeology of urban poverty we require innovations in both methods and ideas, the most far-reaching being a transnational archaeology of urban poverty founded on the analysis of migration, consumption and class formation.  相似文献   

5.
Age-estimation methods tend to under-estimate advanced age and consequently life expectancy of populations. Many methods use age-scales ending in categories such as “50 years and over” without explaining how the upper limits are decided; the general belief that in early times life was short may play a part. Instances now exist of contemporary written records showing that, even when expectation of life is low, some people become septuagenarians or even older. Most methods of age-estimation, commencing with Gustafson's using dental criteria, predominantly root translucency, have recently been scrutinized by several workers but tooth wear as a method has escaped such scrutiny. A wide range of published findings based on tooth wear is therefore reviewed here. Most age-estimating criteria can only be assessed in terms of ordinal stages, unlike root translucency which can be measured on a continuous scale. Tooth wear ultimately ends in total loss of the dentition but, until that stage, has the potential, not yet fully developed, of also being so measured. The revision is reported of the 1989 estimated age-at-death distribution of a skeletal population. Based on tooth wear and tooth loss, the ages of most over 50 years of age were advanced by about 15 years and reasons are given for regarding four as likely to have been over 75 years of age. Palaeodemography today needs such survivors to be identified, however tentatively.  相似文献   

6.
Bison breeding behaviour has been used for the last three decades as the basis for developing methods for assigning season‐of‐occupation estimates to archaeological sites on the North American Plains. These methods are based upon the supposition that the North American bison breeding season is extremely short and that genetically controlled ontological characteristics such as foetal growth and tooth eruption sequences can therefore be used to infer site seasonality in a reasonably straightforward and precise manner. This paper reviews bison population studies conducted during the past 30 years to reassess present understandings of the length of North American bison breeding seasons. It is concluded that the bison breeding season regularly extends over a period of three to four months, and that initiation of ontological development will therefore also vary over the same period of time. Bison development characteristics cannot provide a reliable or precise means of assigning seasonality to archaeological sites on the North American Plains. It is suggested that methods using physical characteristics such as dental cementum incrementation which are directly affected by seasonal changes could be more productive. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

7.
The permeability of the Earth's crust commonly varies over many orders of magnitude. Flow velocity can range over several orders of magnitude in structures of interest that vary in scale from centimeters to kilometers. To accurately and efficiently model multiphase flow in geologic media, we introduce a fully conservative node‐centered finite volume method coupled with a Galerkin finite element method on an unstructured triangular grid with a complementary finite volume subgrid. The effectiveness of this approach is demonstrated by comparison with traditional solution methods and by multiphase flow simulations for heterogeneous permeability fields including complex geometries that produce transport parameters and lengths scales varying over four orders of magnitude.  相似文献   

8.
Cluster analysis is the most widely used multivariate technique in archaeometry, with the majority of applications being exploratory in nature. Model‐based methods of clustering have their advocates, but have seen little application to archaeometric data. The paper investigates two such methods. They have potential advantages over exploratory techniques, if successful. Mixture maximum‐likelihood worked well using low‐dimensional lead isotope data, but had problems coping with higher‐dimensional ceramic compositional data. For our most challenging example, classification maximum‐likelihood performed comparably with more standard methods, but we find no evidence to suggest that it should supplant these.  相似文献   

9.
从染草中提取出各种植物染料,然后进行古样品的模拟染色。以薄层色谱法为主要测试手段,并结合化学分析以及高效液相色谱。紫外光谱等近代方法对染料进行分析与鉴定,建立起一套行之有效的天然植物染料分析和鉴定的方法,并成功地用于古代样品的分析,揭示了三千年前古样品染料色素的成分。  相似文献   

10.
Bayesian Areal Wombling for Geographical Boundary Analysis   总被引:4,自引:0,他引:4  
In the analysis of spatially referenced data, interest often focuses not on prediction of the spatially indexed variable itself, but on boundary analysis , that is, the determination of boundaries on the map that separate areas of higher and lower values. Existing boundary analysis methods are sometimes generically referred to as wombling , after a foundational article by Womble (1951). When data are available at point level (e.g., exact latitude and longitude of disease cases), such boundaries are most naturally obtained by locating the points of steepest ascent or descent on the fitted spatial surface (Banerjee, Gelfand, and Sirmans 2003). In this article, we propose related methods for areal data (i.e., data which consist only of sums or averages over geopolitical regions). Such methods are valuable in determining boundaries for data sets that, perhaps due to confidentiality concerns, are available only in ecological (aggregated) format, or are only collected this way (e.g., delivery of health-care or cost information). After a brief review of existing algorithmic techniques (including that implemented in the commercial software BoundarySeer), we propose a fully model-based framework for areal wombling, using Bayesian hierarchical models with posterior summaries computed using Markov chain Monte Carlo methods. We explore the suitability of various existing hierarchical and spatial software packages (notably S-plus and WinBUGS) to the task, and show the approach's superiority over existing nonstochastic alternatives, both in terms of utility and average mean square error behavior. We also illustrate our methods (as well as the solution of advanced modeling issues such as simultaneous inference) using colorectal cancer late detection data collected at the county level in the state of Minnesota.  相似文献   

11.
This study presents lessons learned from the application of mixed methods during three field visits to central Mediterranean islands over an eight-year period to learn about and from visitors who voluntarily paid to experience ecotourism. The study outlines various challenges encountered in research in small island settings. Such challenges include logistical difficulties to reach islands, including those originating from weather conditions, difficulty in practising observation in small communities, sampling dilemmas, different levels of trust and willingness to disclose views among interview participants, lack of standardised data, language barriers that may limit who conducts research on specific islands, and substantial fluctuations in population size throughout the year. Findings show that the choice and application of methods for island research need to be informed by island dynamics; this entails adapting methods and using different data collection techniques to mitigate challenges arising from island settings. The study also outlines the need of more research in the application of mixed methods when studying islands.  相似文献   

12.
M. J. BAXTER 《Archaeometry》2008,50(6):968-982
This review of developments in the use of mathematics and statistics in archaeometry over the past 50 years is partial, personal and ‘broad‐brush’. The view is expressed that it is in the past 30 years or so that the major developments have taken place. The view is also expressed that, with the exception of methods for analysing radiocarbon dates and increased computational power, mathematical and statistical methods that are currently used, and found to be useful in widespread areas of application such as provenance studies, don't differ fundamentally from what was being done 30 years ago.  相似文献   

13.
C. A. POOL 《Archaeometry》2000,42(1):61-76
The benefits of one ceramic firing technology over another are not absolute, but depend upon the interaction of multiple environmental, economic and social factors, as well as the specific design of firing facilities. The coexistence of updraft kilns and open firing methods in the Sierra de los Tuxtlas, Veracruz, Mexico, for over 1700 years provides a case‐in‐point. Evaluation of the performance characteristics of ancient and modern firing technologies in relation to their natural and behavioural contexts offers a more secure basis for understanding this specific historical instance of long‐term polymorphism than explanations based in the generalized technological advantages of kilns or their cross‐cultural association with intensive modes of production.  相似文献   

14.
The collection and analysis of 3D digital data is a rapidly growing field in archaeology, anthropology, and forensics. Even though the 3D scanning of human remains in archaeology has been conducted for over 10 years, it is still frequently considered as a new field. Despite this, the availability of 3D scanning equipment and the number of studies employing these methods are increasing rapidly, and it is arguably damaging to the validity of this field to continue to consider these methods new and therefore not subject to the same standardisations as other researches. This paper considers the current issues regarding the lack of standardisation in the methods, ethics, and ownership of 3D digital data with a focus on human remains research. The aim of this paper is to stimulate further research and discussion, allowing this field to develop, improving the quality and value of future research.  相似文献   

15.
The chemical compositions and microstructures of some 35 faience objects from Egypt spanning the period from the Middle Kingdom through to the 22nd dynasty are determined using analytical scanning electron microscopy. Replicate faience beads glazed in the laboratory using the efflorescence and cementation methods are similarly investigated. In efflorescence glazing, there appears to be preferential efflorescence of soda over potash, and in cementation glazing, preferential take up of potash over soda into the glaze. These data are then used to try to infer the raw materials and methods of glazing employed in the production of the ancient faience. The glaze/glass phases present in the faience differ significantly in composition from that of New Kingdom glass. This could be due either to the use of different plant ashes or to changes in the composition of the plant ashes during the production of faience and/or glass. Although it is only rarely possible to determine with certainty whether ancient faience was glazed by efflorescence, cementation or application, the observed microstructures provide an indication of the approach adopted to achieve desired performance characteristics such as strength.  相似文献   

16.
This paper presents a first attempt to use oblique incidence ionograms over the 4500 km path from Sanae, Antarctica, to Grahamstown, South Africa, to deduce information about the ionosphere in the intervening regions. It is shown that existing methods for the reduction of oblique incidence ionograms to N(h) profiles give reasonable results even over the two-hop path involved. By comparison with vertical incidence ionograms made from a research ship below the reflection regions it is shown that the maximum observed frequency is normally limited by conditions at the southernmost reflection point, though this may be modified by ionospheric tilts, sunrise and sunset.  相似文献   

17.
The author proposes methods for desalting brackish or salty groundwater in the arid zone for use in animal husbandry and crop raising. Stock-raising needs would be met by storing freshwater obtained in winter for year-round use. Crop production would be made possible by freezing a layer of ice over prospective cropland and saturating the soil with meltwater in the spring as in the basin system of once-a-year irrigation.  相似文献   

18.
We develop tests of whether a pattern of geographic variation departs significantly from random variation over an area. Localities are vertices in a graph whose edges are connections based on criteria of geographic contiguity. Ranked variables are assigned to each locality. Distributions of absolute differences in rank along edges between vertices yield various statistics of edge length that are compared with expectations developed in the paper. Several typical patterns such as a cline, depression, or a crazy-quilt are generated and their behavior characterized by this method. Computational and graphical methods allocate observed patterns to one of several types. The methods are general; three illustrative examples from biology and one from regional studies are furnished.  相似文献   

19.
为了了解上海松江广富林遗址出土周代铜器合金配比和加工工艺特点,对18件该地区出土周代铜器进行检测分析。使用X射线荧光光谱仪(XRF)和金相显微镜分析青铜样品的成分组成及金相显微组织并发现:样品中铅锡青铜器占绝大多数,器物含铅量普遍较高,且大多含少量砷;器物基本都是铸造成形,仅有少量实用工具、农具刃口进行过热锻等加工处理,以提高使用性能。结果反映了当时工匠对铸造合金配比和加工工艺的认知和技术水平,也体现了吴越地区独特的青铜技术体系与文化,能够为南方史前及先秦文化的发展脉络提供更多可供探讨的资料。  相似文献   

20.
Charcot-Marie-Tooth disease is a hereditary motor and sensory neuropathy first described in 1886. Our increasing knowledge of this disease correlates well with the development of methods used in neurology over the past 100 years. Although its physiopathology and treatment is still not fully understood, current developments in techniques are opening the way to future discoveries. We have divided its history into three theoretical periods: the first from 1886 to 1956, which was devoted to clinical and pathological study of the disease; the second from 1956 to 1982, which saw the development of electromyography in the investigation of neuromuscular diseases; and the last and current period based upon genetic research, using the methods of molecular biology.  相似文献   

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