On Theme and Variation

Abstract

The ways in which the author, the sculptor Peter Randall-Page, has made use of the ideas of D’Arcy Thompson are described. How Thompson showed that commonalities of form and pattern exist across the biological and abiotic realms is described, and the implications that physical constraints limit and sometimes dominate the capabilities of evolutionary natural selection are explored. Since we evolved in a world shaped in this manner, the likelihood that this palette of forms is one that carries strong psychological meanings and associations is examined, and the ways in which these forms are a rich source of inspiration and allusion for visual artists are discussed, hinting at the play of opposing tendencies, the dance between order and randomness, and the ways in which nature can derive variations on a theme.     

Identifying of buried archaeological remains with ground penetrating radar,polarized microscope and confocal Raman spectroscopy methods in ancient city of Nysa,Aydin – Turkey

The aim of this study was to image buried remains and appoint buried Hellenistic street system, and identify minerals and rock types of the ancient city of Nysa, one of the most important historical sites of Turkey. This study used polarized microscope and confocal Raman spectroscopy (CRS) ground penetrating radar (GPR) method, to identify the buried remains, rock types and minerals.     

多种科技方法在古月桥勘察修缮设计中的应用

建于南宋嘉定六年(公元1213年),位于浙江省义乌市的古月桥是折边拱桥这种桥梁发展过渡形式中不可多见的典型实证,具有极高的历史、科学、艺术、文化和社会价值。为了明确古月桥目前的状态,分析其主要威胁及病害原因,判断结构稳定性,进而制定有针对性的修缮方案,采用多种科技方法对古月桥进行了勘察和综合判断。面对桥身残破的现状,工作组采取了三维激光扫描、微观实验、结构分析等多种科技方法综合勘察,不仅较为清晰的地了解了古月桥的病害威胁,也分析了其背后致因及相互之间的联系;最终对古月桥稳定性及保存状况做出了综合判断。上述多种方法的应用,不仅相互印证了勘察结论,也为后续保护工作提供了重要的依据。     

Securing the Return: How Enhanced US Border Enforcement Fuels Cycles of Debt Migration

Expanded border enforcement has made unauthorised migration to the US more risky, costly, and prone to failure. Research on the material consequences of border enforcement for migrant‐sending households in Central America reveals that the economic hardships enforcement exacts on migrants at times diminishes enforcement's desired deterrent power. Heightened risks have driven up the cost of migration and pushed many to fund their trips through loans. Consequently, migrant detention, deportation, or death can result in poverty and privation for indebted households and the seizure of loan collateral, typically homes and land, in turn prompting crises in household reproduction. With a US wage the most viable means to ameliorate economic hardships, enforcement outcomes push some to return migration. Our findings suggest that US border enforcement efforts at times perpetuate the very unauthorised migration they seek to impede, while also helping to reproduce the border itself by deepening the marginalisation that drives migration decisions.     

Effects of Geometrical Features on the Seismic Response of Historical Masonry Towers

ABSTRACT

Historical masonry structures are often located in earthquake-prone regions and the majority of them are considered to be seismically vulnerable and unsafe. Historical masonry towers are slender structures that exhibit unique architectural features and may present many inadequacies in terms of seismic performance. The seismic protection of such typologies of structures and the design of effective retrofitting interventions require a deep understanding of their behavior under horizontal loads. This paper presents the results of the seismic performance evaluation of historical masonry towers located in Northern Italy. A large set of case studies is considered, comprising a significant number of towers with high slenderness and marked inclination. First, a preliminary assessment of the dynamic behavior of the different towers is carried out through eigenfrequency analyses. Then, non-linear dynamic simulations are performed using a real accelerogram with different peak ground accelerations. A damage plasticity material model, exhibiting softening in both tension and compression, is adopted for masonry. The huge amount of results obtained from the non-linear dynamic simulations allows a comparative analysis of the towers to be performed in order to assess their seismic vulnerability and to show the dependence of their structural behavior on some geometrical characteristics, such as slenderness, inclination, and presence of openings and belfry. The evaluation of different response parameters and the examination of tensile damage distributions show the high vulnerability of historical masonry towers under horizontal loads, mainly in the presence of marked inclination and high slenderness. Some general trends of the seismic behavior of the towers are deduced as a function of the main typological features.     

The Determinants of Political Cleavages in Jordan,Tunisia, and Yemen: An Analysis of Political Attitudes Structure in the Arab World

This article investigates the determinants of political cleavages composing the structure of political attitudes in Jordan, Tunisia, and Yemen following the Arab Spring. Further, it tests whether political cleavages carry predictive weight on ordinary citizens’ electoral choices in general elections. Using the Sixth Wave of the World Values Survey, discriminant analysis was conducted to generate the dimensionality, type, and structure of political attitudes in the three nations. Findings suggest that the structure of political attitudes in Jordan, Tunisia, and Yemen is multidimensional: the Islamic‐Secular division, a conflict along economic policy visions and an emerging divisive dimension concerning political reform. Evidence indicates that political cleavages do not possess significant predictive power in determining voters’ choice at elections booths. This research also points to the significance of social transformation processes such as modernization and globalization in causing a shift in values among ordinary citizens in the Arab World. This research argues that in countries where the effects of modernization and globalization are higher, a weakening of the Islamic‐Secular division is witnessed. This research is important since it paves the way for further empirical analysis on political ideology in the Middle East. It shatters conjectures concluding that Arab polities are only divided by a single hierarchical dimension: Islamic‐Secular. It contributes to comparative research on the dimensionality of political ideology by showing that the Arab World is similar to the industrialized world in the dimensionality, nature, and structuration of political ideology.     

Electrical Resistivity Tomography with Angular Separation for Characterization of Burial Mounds in Southern China

The study aims at providing the spatial distribution and potential structure of the burial mounds at the Sifangling site, Hepu Han Tombs, in southern China. We implemented an electrical resistivity tomography (ERT) technique to obtain high‐resolution imaging of archaeological targets, considering the challenging environment and the depth of the burials. Three ERT profiles were tested above a small ancient mound previously detected by exhaustive archaeological drillings, following which 18 ERT profiles with angular separation were performed on the largest mound at the test site, without any a priori archaeological evidence below the surface. Then, a series of two‐dimensional (2D) profiles were combined as a ‘pseudo‐3D’ volume, which allowed a detailed characterization of the burial mound, and iso‐resistivity surfaces were also calculated to emphasize the location and spatial extent of the target. The results gave an effective identification of the funeral chamber and its structural details, and allowed detailed pre‐excavation planning.     

IN VITRO DECOMPOSITION OF BONE COLLAGEN BY SOIL BACTERIA: THE IMPLICATIONS FOR STABLE ISOTOPE ANALYSIS IN ARCHAEOMETRY*

To understand biogenic collagen type I decomposition and to establish how diagenesis may bias archaeometric data, modern mammalian bone was inoculated with a selection of ubiquitous soil bacteria. The presence of exogenous microbial biomass in the inoculated specimens was then checked microscopically prior to collagen extraction. The experimentally degraded bone collagen showed altered amino acid compositions, attributable to the selective breakdown of certain amino acids by the bacteria. While both the bulk collagen extract and the single amino acids exhibited shifts to more negative δ¹³ C-values, enrichment was recorded for general δ¹³ N, and a depletion trend relative to unaltered collagen was observed for individual amino acid δ¹³ N. One explanation for the enrichment of the global δ¹⁵N-values is cleavage of peptide bonds, which leaves ¹⁵ N within the substrate, while the change of ¹³C is mostly due to the altered amino acid composition. On the other hand, possible repolymerization of cleavage products under experimental conditions may also be responsible for the depletion trend of individual amino acid δ¹³C- and δ¹⁵ N-values. This paper discusses the results as a basis for the development of a method for the reconstruction of the isotopic abundance of the original collagen, using the amino acid composition of the degraded product, the contribution of individual amino acids to its global δ-values and of isotope discriminations implied in the microbial decomposition.