Sapwood estimates in the interpretation of tree-ring dates

Many timber finds lack some or all of the outer, sapwood rings formed in the years just before felling. In order to estimate felling date once the outermost remaining ring has been dated, it is necessary to estimate the number of sapwood rings originally present. Methods doing this for oak are reviewed in the light of an intensive study of living trees at one site and an extensive study of 175 samples from living trees in North Wales and northwest England. Some methods reported in the literature are found to be invalid. A method reported by Hollstein (1965) is most reliable, with modifications for known variations in sapwood number with position in the tree. At present the best available estimate is that a value of 30 sapwood rings be used (95% confidence limits: 19–50).     

A Bayesian approach to rapid seismic vulnerability assessment at urban scale

The seismic vulnerability of city centers is commonly assessed by extending the study methods applied to single buildings to urban aggregations. This approach is not always applicable at territorial scale, as it is uneconomical in terms of time and costs. An innovative method provides reasonable large-scale a priori estimation of parameters not directly evaluable from the exterior of buildings by elaborating values which can be measured from the outside. Those parameters are treated as continuous variables, by assigning them a suitable probability density function. The Bayesian approach is adopted, which allows the update of initial hypotheses by using new data gathered during on-site surveys. In this regard, a rapid survey form for the on-site data collection is proposed. An example of its application to a façade of a building structural unit in Santo Stefano di Sessanio in L’Aquila province (Italy) is proposed, showing promising preliminary results for buildings belonging to Italian historical centers.     

3D Digital Survey of Iron Tie-Rods in Masonry Buildings: Cross-Sections Analysis and Error Estimation

Ancient iron tie-rods are handcrafted elements with large geometric irregularities, due to production techniques (they are shaped by hammering and linked by hot-forging) and corrosion processes. In common practice, their cross section (that is one of the main parameter to assess their strength) is manually measured on site with a manual caliber. By analyzing a set of detailed three-dimensional (3D) digital surveys of real ancient tie-rods, this study provide an evaluation of the errors made by in-situ manual geometric measurements. In particular, it shows that, in some cases, manual on-site survey is sufficiently reliable and has errors that fall below 10%. Moreover, it shows that when tie-rods have high corrosion levels in hidden zones (typically those close or within the retaining walls) the on-site survey of visible parts only may produce far greater errors that exceed 100%, leading to a strong overestimation of the cross-section of the tie. The ongoing study is a first step toward the definition of correction coefficients to be applied to the on-site manual measurements of ancient tie-rods, with the final aim to improve the reliability of structural analyses.     

Quantifying artefacts over time: Interval estimation of a Poisson distribution using the Jeffreys prior

This paper presents a new method for estimating the amount of an artefact class in use at a given moment in the past from a random assemblage of archaeological finds. The method is based on the use of simulation, since an analytical solution is computationally impractical. Estimating the number of artefacts in use at any time t is shown to follow a Poisson distribution, which allows for credible intervals to be established using the Jeffreys prior. This estimator works from minimal assumptions about the dating and duration of finds, as well as the intensity of collection, and is applied to coinage from four Roman‐period sites excavated by the Roman Peasant Project (2009–14). The result provides an estimation of the abundance of material according to an interval of certainty.     

Collagen deamidation in archaeological bone as an assessment for relative decay rates

Attempts to extend methods for dating archaeological bones beyond that of radiocarbon dating, such as amino acid racemization, have met with limited success owing to the dependence on multiple environmental factors and controls. Despite facing similar challenges, deamidation of glutamine has recently been investigated as a potential indicator of ‘thermal age' in archaeological bones, as well as a measure of their preservation quality. In this study, we undertook a series of simulated diagenetic experiments to understand the various factors affecting deamidation. Further, we analysed bones from different Middle Palaeolithic layers from Grotte Mandrin (France), with the results suggesting potential use of deamidation for relative dating, but only in case of extremely well‐preserved layers. The results also suggested the possible use of attenuated total reflectance‐Fourier transform infrared (ATR‐FTIR) spectroscopy as a screening test for soluble collagen before proteomic analysis.     

前剂量饱和指数法测定瓷器的热释光年代

用前剂量饱和指数法测定39件历代瓷器的热释光年代。结果表明,热释光年代与考古年代在一个标准偏差(±1σ)为29％以内的一致性非常良好。这样的误差在瓷器年代测定中是可以接受的。     

The estimation of live fish size from archaeological cranial bones of the New Zealand blue cod Parapercis colias

Twenty-four measurements were taken on five of the paired cranial bones and the otoliths of a modern sample of 177 blue cod. Parapercis colias. Regression analysis was performed on these measurements to estimate live fork length and ungutted weight. A number of regression models were examined (linear, logarithmic, exponential and power curve) to work out the optimum estimator for each bone measurement. It was found that live fork length of this species can be estimated with a standard error of less than ±28 mm, and the weight to less than ±140 g. Coefficients are provided for 48 equations linking bone size to live characteristics. This is followed by a study of blue cod from an archaeological site at Waihora in the Chatham Islands. Measurements were made on 8036 archaeological bones with a minimum number of individuals of 2547. It was found that the blue cod catch had near normal characteristics, with a mean fork length of 327 mm and SD of 57 mm. The mean body weight was estimated at 569 g. The usable meat weight represented by these fish is estimated to be 1.0 t. © 1997 John Wiley & Sons, Ltd.     

Exploring the land development process and its impact on urban form in Hamilton, Ontario

The form of many Canadian cities has dramatically evolved over the past six decades due to urban sprawl. Several patterns can characterize this evolution including unlimited horizontal expansion of the city, leapfrog, and low‐density residential development at the outskirts, and widespread strip commercial and power centre retail development. Hamilton, Ontario is an example of a Canadian city that has experienced suburbanization and sprawled development for several decades. However, the nature of this sprawled development is unclear and its impact on urban form is not entirely understood. In this article, several hypotheses pertaining to sprawled land development and urban form are postulated and tested. The tests rely on point source data of the developed land parcels in Hamilton during the period 1950–2003. A number of spatial statistics techniques, including kernel estimation and complete spatial randomness (CSR) K‐function tests, are employed to examine the emerging nature of urban form. We hypothesize that while the city has been sprawling, the ongoing land development process is leading urban form into multinucleation. To support this assumption, we further hypothesize the existence of an interdependent spatial relationship between residential and commercial land uses at the emerging nuclei. Accordingly, we examine the strength of co‐clustering among these land use activities over time. The findings indicate that while the city has been sprawling, several consequent urban nuclei with mixed land use activities have been emerging and become more visible in recent years. This is an indication that the city's form is progressively becoming multinuclear. Furthermore, the estimates for the 1990s indicate interdependence between the locational patterns of residential and commercial land development. Co‐clustering between these two types of land uses is bi‐directional and occurs at a time lag of three to seven years. These findings affirm the existence of interdependence between land use activities at the observed nuclei, which support the emergence of a multinucleation.     

陶器古剂量线性回归方法和误差评估

陶器古剂量P包含等效剂量Q和超线性修正I两个部分,为了提高古剂量测量的准确性,正确地计算古剂量的测量误差,本工作测试了10个古陶片样品,利用线性回归方法计算等效剂量Q和超线性修正I,并对不同的古剂量计算方法进行误差分析和评估。研究表明,线性回归方法(包括归平法和平归法)计算陶器古剂量的准确性优于目前采用的常规法;通过几种不同方法的误差比较和分析,归平法所得误差较其它方法更严谨、合理。该研究在提高古剂量测量的准确性和正确计算古剂量的测量误差两方面具有重要的意义,使得古剂量的测量更加合理,符合数理统计规律。     

Evaluation of IBC Equivalent Static Procedure for Base Shear Distribution of Seismic Isolated Structures

It has been pointed out that the static lateral response procedure for base isolated structures presented in IBC somewhat overestimates the seismic story force [Lashkari and Kircher, 1993 Lashkari, B. and Kircher, C. A. . Evaluation of SEAOC/UBC analysis procedures, Part 1: Stiff superstructure. Proceedings of a Seminar on Seismic Isolation, Passive Energy Dissipation and Active Control. Redwood City, California. ATC Report 17-1.  [Google Scholar]; Constantinou et al., 1993 Constantinou, M. C., Winters, C. W. and Theodossiou, D. . Evaluation of SEAOC and UBC analysis procedures, Part 2: Flexible Superstructure. Proceedings of a Seminar on Seismic Isolation, Passive Energy Dissipation and Active Control. Redwood City, California. ATC Report 17-1.  [Google Scholar]]. In this article IBC equivalent static method for base shear distribution of seismic isolated structures is evaluated. For this purpose one-story to six-story building models are designed according to equivalent lateral response procedure for different elastomeric isolation systems. The results of equivalent lateral response procedure in parameters such as base shear and vertical distribution of base shear are compared with results obtained from dynamic nonlinear analysis and the efficiency and limitations of its application are investigated. In general, the results of equivalent lateral response procedure in base shears are acceptable within the scope of this procedure, but the proposed triangular distribution of base shear is somewhat conservative. So a new formulation for vertical distribution of base shear is proposed which results in a more realistic distribution of shear over the height of isolated buildings. The accuracy of the new formulation is examined by comparing the resulting responses obtained from this study with those calculated by nonlinear time history analysis.