System of measurement of the severity of periodontal disease in past populations

This paper presents a review of the antiquity of periodontal disease, discussing past aetiological concepts in comparison to current research on the causes of this condition. As periodontal disease is analysable on dry bone specimens, it is possible to document its natural history. To date, little work has been done on an actual system of measurement for periodontal disease in such specimens. A new system of measurement is proposed, which is confined to evaluating the periodontal status of post-mortem skulls. The system is a modification of the Ramfjord index for periodontal disease (PDI) and can be adapted for both individual specimen measurement and for population studies. Seven skulls, ca. AD 500–700, from the Varden Site at Long Point, Ontario, were examined using the proposed system. Mean attachment loss was computed for each of the seven specimens. The results revealed one specimen with early periodontitis, four with moderate periodontitis and two with advanced periodontitis. This system provides a concise method for classification of the severity of periodontal disease in dry bone specimens that will be useful in documenting the history of this disease.     

多类型微博舆情时空分布关系的差异性及其地理规则

以新浪微博转发行为作为舆情时空分布的研究对象,分别选取4·20雅安地震事件代表重大社会舆情、凤凰古城收费事件代表公众生活舆情、郭某某事件代表网络热点舆情3类案例,总结不同类型微博舆情的时空分布特征及差异性,进而透视客观存在的地理规则。研究发现：①3类舆情事件微博转发量的时间分布分别表现为：长尾型、山峰型、多个时间段上的波浪型。②与时间轴对应的空间分布呈等级结构,信息扩散节点城市等级（转发量）结构还会表现出一定的空间伸缩变形或与距离衰减形成叠加关系,3类事件分别表现为：延续传统规律的“始终金字塔”结构、在相对较长时间过程中具有范围伸缩的“始终金字塔”结构、距离衰减影响下的“始终金字塔”结构。城市规模效应主导和距离摩擦阻尼效应影响构成网络信息空间分布的基本地理规则。③微博舆情时空分布的差异性与事件类型有关,并与不同微博用户的作用有关。微博用户的不平衡区域分布和其跨区域流动对信息空间分布产生直接影响。     

Endocranial lesions in non‐adult skeletons: understanding their aetiology

Reactive new bone on the endocranial surface of the skull in non‐adults has recently received a lot of attention in the palaeopathological literature. These features appear as layers of new bone on the original cortical surface, expanding around meningeal vessels, as isolated plaques, ‘hair‐on‐end’ extensions of the diploë or, as ‘capillary’ impressions extending into the inner lamina of the cranium. These lesions are commonly found on the occipital bone, outlining the cruciate eminence, but have also been recorded on the parietal and frontal bones, and appear to follow the areas of venous drainage. Although recognized as resulting from haemorrhage or inflammation, their precise aetiology is still a matter of controversy. This paper outlines their possible causes and examines their nature and distribution in a group of non‐adults from four archaeological sites in England. It is recommended that, when recording these lesions in the future, additional skeletal pathologies, the age of the child, and nature and distribution of the lesions also be taken into account. Copyright © 2004 John Wiley & Sons, Ltd.     

Differential diagnosis of a prehistoric biological object from the Koster (Illinois) Site

This paper details the differential diagnosis of a biological artifact recovered from a burial within the Koster Middle Archaic site in Illinois. The burial was excavated from the Middle Archaic 3, Helton Phase component (∼5800–4900 BP). The artifact was a calcified nodule of unequivocal biological origin recovered from the pelvic region of an adult (50+ years) female. Morphological and radiographic analysis of the object resulted in the consideration of 19 possible diagnoses; all but four could be eliminated. Possible interpretations of the object as a lithopaedion, calcified lymph node, amputated ovary or simple ovarian cyst are examined in detail. Of these, calcified lymph node or amputated ovary remain most probable. Copyright © 2003 John Wiley & Sons, Ltd.     

Making the Brain Plastic: Early Neuroanatomical Staining Techniques and the Pursuit of Structural Plasticity, 1910–1970

The concept of neuronal plasticity is widely used, but seldom defined in the neurosciences. It can signify many different occurrences, such as structural alterations of axons and dendrites (Cotman & Nadler, 1978), behavioural adaptations (Rosenzweig & Bennett, 1996), or physiological changes in synapse formation (Martin et al., 2000) at different stages of health and disease. Although there is such a wealth of research from many disciplines, the neuroanatomical aspects of plasticity are the focus of this paper. It seeks to illuminate the evolution of different concepts of plasticity concerning the structure and circuitry of the central nervous system (CNS). Early modern morphological research on de- and regeneration phenomena in the 19th- and early 20th-century is well documented. These studies, however, almost exclusively concentrated on the peripheral nervous system (PNS). It was one of the major contributions of Santiago Ramón y Cajal (1852–1934), that he applied the concept of regenerative capacities to the CNS. But the term plasticity seemed to have disappeared for about two decades after his death. The ensuing comeback of the expression may be attributed, at least in part, to new neuroanatomical staining and tracing methods. The pursuit of these techniques will serve as a guidepost through varying approaches in different times: It was the 1950s which seemed to spawn the time for new departures in structural investigations of neuronal plasticity.     

Schmorl's nodes: clinical significance and implications for the bioarchaeological record

Back pain is one of the major contributors to disability and loss of productivity in modern populations. However, osteological correlates of back pain are often absent or, as yet, unidentified. As bioarchaeologists depend on osteological evidence to interpret quality of life in the past, back pain, with its profound effects on modern populations, is largely overlooked in archaeological samples. This study addresses this shortcoming in bioarchaeological analysis by exploring the relationship between a defined vertebral osteological lesion, the Schmorl's node, and its effect on quality of life in a clinical population. Using patient insight, healthcare practitioner diagnoses and MR imaging analyses, this study investigates: (1) Schmorl's nodes and sociodemographic factors; (2) the number, location and quantitative aspects (e.g. length, depth, area) of Schmorl's nodes, and how these influence the reporting of pain; (3) the dynamic effects of Schmorl's nodes, in combination with other variables, in the reporting of pain; and (4) the perception and impact of pain that patients attribute to Schmorl's nodes with regard to quality‐of‐life issues. The results of this study indicate that Schmorl's nodes located in the central portion of the vertebral body are significantly associated with patient reporting of pain, and that the presence of osteophytes, in the affected vertebral region, may increase the likelihood that an individual will report pain. This finding provides bioarchaeologists with an osteological correlate to begin interpreting the presence and impact of pain in archaeological populations, with implications for scoring Schmorl's nodes. Copyright © 2007 John Wiley & Sons, Ltd.     

Schmorl's nodes in a post‐medieval skeletal sample from Klostermarienberg,Austria

The prevalence and distribution pattern of Schmorl's nodes (SNs) were studied in a post‐medieval skeletal sample (n = 473) from the 16^th–18^th century cemetery of Klostermarienberg, Austria. The reasons for the prevalence and distribution pattern of SNs in this sample are discussed with regard to their aetiology. SNs were correlated with age and sex as well as with degenerative spinal joint disease such as vertebral osteophytosis (VO) and apophyseal osteoarthritis (OA). SNs were most commonly found in the lower thoracic region, in agreement with other studies. Males were more affected than females by SNs, especially in the lower thoracic region. SNs show a completely different distribution pattern to VO and OA. Additionally, there was no relationship found between SNs and ageing. Observed differences in the prevalence of SNs in the vertebral column and between the sexes suggest that mechanical factors may be responsible. Copyright © 2008 John Wiley & Sons, Ltd.