Canaletto’s paintings open a new window on the relative sea-level rise in Venice

The paintings by Canaletto (1697–1768), made with the help of a camera obscura, are just like real photographs, documenting as they do the Venice of the XVIII century with an accurate reproduction of all the details. The brown–green front left by the Laminaria, an alga living between the high and low tide, constitutes a precise biological indication of the average level of the high tide. By comparing the level of this front at Canaletto’s time with the present level, we can calculate/discover the relative sea level rise which has occurred in the last two and a half centuries.     

A color image segmentation method as used in the study of ancient monument decay

In the cultural heritage area, it is of fundamental importance to characterize and classify the conservation state of the materials constituting ancient monuments, in order to study and monitor their decay. Generally, the decay diagnosis is provided by “naked eye” analysis done by expert scientists “walking around” the artifact and recording the conservation state of each individual element they observe. In this paper, a color image segmentation approach, based on histogram threshold and edge detection techniques is presented, to extract degradation regions, characterized by holes or cavities, from color images of stone-materials. The goal is to provide an aid to the decay diagnosis by segmenting degraded regions from color images, computing quantitative data, such as the area and perimeter of the extracted zones, and processing qualitative information, such as various levels of depth detected into the same zones. Since color is a powerful tool in the distinction between objects, a segmentation technique based on color, instead of intensity only, has been used to provide a clearer discrimination between regions. The study case concerns the impressive remains of the Roman Theatre in the city of Aosta (Italy). In particular, we have processed and analyzed some color images of the theatre puddingstones, acquired by a camera.     

Environmentally-induced stone decay: the cumulative effects of crystallization–hydration cycles on a Lincolnshire oopelsparite limestone

An investigation has been undertaken at St Andrew’s church, Walpole St Andrew, Norfolk, to establish the underlying causes of the observed stone decay to the upper parts of the six stone piers. The stone decay was first recorded in the early 1930s. The salt-contaminated masonry within the church has been shown to undergo severe salt decay during the summer, with little damage occurring over the winter months. The south aisle piers have been shown to decay 2.5 times faster than the north aisle piers. Although crystallization–hydration cycles have been identified, the rate of decay is at its greatest when the cycling is relatively infrequent. This was not the expected trend. Furthermore, it has been shown that during extended periods where the ambient relative humidity is less than 75%, the rate of decay reaches a maximum. It is the length of this ‘drying’ period that apparently has the greatest influence on the rate of decay and could explain the significant difference in the rate of decay between the south and north aisle piers. The results have serious implications for passive conservation, where it is often recommended to lower the ambient relative humidity to well below the equilibrium relative humidity of the salt contaminant, to avoid crystallization–hydration cycles. Since, at the time of building, the church was situated on the coast, it is possible that the sodium chloride contamination occurred during the building process (1440–1520), particularly since the area was prone to sea-flooding at this time. Alternatively, the salt could have been applied as a treatment during the general restoration of 1897. Whatever the source of the salt, it seems likely that the ambient environment was changed by the insertion of a sealed floor in 1897, which could account for the onset of the salt decay.     

中国档案文献近代散佚述论

档案文献是历史研究的第一手资料。由于自然和人为的原因，近百年来，中国档案文献蒙受了重大损失，教训深刻，发人深思。     

卡多话衰变现状研究

卡多话是哈尼族卡多支系人所说的一种语言,属于哈尼语碧卡方言,其使用人口约有18万。近20年来,随着社会的发展,卡多话呈现出一种衰退的趋势。围绕卡多话的衰退现象,从语言使用的现状、词汇能力以及语言本体的衰退表现三个方面来论证和揭示卡多话衰退的现状,并探究其衰退的原因。     

不可压渗流方程解的衰减性

考虑不可压渗流方程,利用半群e^-t（-d）n算子的性质,研究当初值充分小时,方程的解在空间PM^n＋1-2a（Rn）中的整体衰减速率。     

专制文化背景下弱者的自我沦丧--卡夫卡《变形记》新解

片面地强调<变形记>体现的是"资本主义社会中"人的异化似乎淡化了卡夫卡所处的时代及文化背景,显得过于强调其现代性而忽略传统文化的影响.卡夫卡是从传统中来的,其作品在表现"异化"方面与后来的以及当时的一些资本主义高度发达国家的作家、作品尚有一段距离.从20世纪初奥匈帝国的文化环境和卡夫卡的精神特质出发,探讨专制文化在造成<变形记>人物"异化"方面的突出意义十分必要.     

Decay of softwood in archaeological wooden artifacts

Hardwoods and softwoods were used side by side throughout Egyptian history, and importing softwoods that had an attractive color and texture was common. Over the decades, artifacts based on hardwoods and softwoods underwent deterioration phenomena, sometimes reaching either a level of brittleness or turning into a wood powder that may easily crumble. These levels of decay/degradation are often difficult to handle in terms of conservation treatments. To study or identify the reasons for decay has always been a point of interest for conservation purposes, but to assess decay and choose an appropriate treatment according to the state of preservation for the sake of keeping an artifact intact has become a subject of major importance. It is difficult at times to understand the deterioration process, because hardwoods and softwoods are different in structure, properties, and chemical composition. For this preliminary study, decayed samples from three commonly used softwood types, cypress (Cupressus sp.), cedar (Cedrus sp.), and pine (Pinus sp.), were identified and chosen. Scanning electron microscopy (SEM) of the samples indicated the degree of decay. Decayed and non-aged samples of the same wood type were analyzed using Fourier transform infrared spectroscopy (FTIR), and all the major carbohydrate and lignin bands were recorded. The strong hydrogen bonded (O–H) stretching absorption associated with water linked by hydrogen bonds to the –OH groups of cellulose and hemicelluloses in all decayed samples increased with decay. The brown powdery, fragile samples that had been evidently affected by microbial decay had a higher amount of lignin. The lignin/carbohydrate ratio was calculated and results compared. The increase of either lignin percentage or extractives in some of the samples had caused a darkening of color in both cypress and cedar samples, but the pine sample did not have the same texture and appearance. In cases where the lignin percentage decreased the samples had changed to a slightly lighter color. FTIR results explained the decay phenomena observed in SEM micrographs and helped assess wood decay and also confirmed results that had been previously obtained while applying traditional chemical analysis on wood.     

旅游地客源市场空间结构与经济水平之间关系的研究--以扬州瘦西湖风景区为例

以扬州瘦西湖风景区为例，对旅游地客源市场空间结构与经济水平之间的关系进行了深入研究，对客源地经济水平影响游客入游率的规律进行了探讨。研究表明，距离因素和经济水平因素对游客入游率的影响具有协同作用，通过入游率、距离和客源地人均可支配收入统计分析和研究，入游率以对数形式随距离和经济水平而变化，入游率的等高线呈一系列辐射状直线族。     

Neutrinos and our Sun — Part 1

The elusive neutrinos have periodically yielded their secrets to man and at each such juncture major advances have been achieved in our understanding of the sub-atomic phenomena. These particles also carry invaluable information about the centre of the Sun where energy is generated through nuclear fusion. In Part I of this article, history of the discovery of neutrinos is traced, their properties and types are described. Also, the Standard Model which forms the basis of the structure of matter and of which massless neutrinos are an integral part, is described. The role of neutrinos in solar energy generation and the great ‘solar neutrino puzzle’ and its solution will be described later in the series.