Gradual Certified Programming in Coq

Expressive static typing disciplines are a powerful way to achieve high-quality software. However, the adoption cost of such techniques should not be under-estimated. Just like gradual typing allows for a smooth transition from dynamically-typed to statically-typed programs, it seems desirable to support a gradual path to certified programming. We explore gradual certified programming in Coq, providing the possibility to postpone the proofs of selected properties, and to check "at runtime" whether the properties actually hold. Casts can be integrated with the implicit coercion mechanism of Coq to support implicit cast insertion a la gradual typing. Additionally, when extracting Coq functions to mainstream languages, our encoding of casts supports lifting assumed properties into runtime checks. Much to our surprise, it is not necessary to extend Coq in any way to support gradual certified programming. A simple mix of type classes and axioms makes it possible to bring gradual certified programming to Coq in a straightforward manner.Comment: DLS'15 final version, Proceedings of the ACM Dynamic Languages Symposium (DLS 2015

Honeycomb sterna: an unusual case of a developmental abnormality in the sternum

This report details an unusual case of a human sternal developmental abnormality of an anatomical specimen part of the skeletal collection curated by University College London, Anthropology Department skeletal collection. This rarely reported developmental abnormality is caused by the non-fusion of lateral ossification centres in the sternebrae, resulting in the mesosternum having a honeycomb-like appearance. Sternal defects are typically underreported in the clinical literature as many cases being asymptomatic that they are typically diagnosed incidentally, as such there is a dearth in our current understanding of the development and anatomical variants of the sternum. Although in recent years, large-scale CT studies have investigated the prevalence of sternal developmental abnormalities, these studies have not reported sternal defects similar to the individual presented in this report. While most sternal defects are clinically uneventful, the lack of awareness of these variants can result in misinterpretation of radiological and pathological findings as such an understanding of anatomical variants even when asymptomatic is vital

A palaeoepidemiological investigation of osteomata, with reference to medieval Poland

The osteoma, among other forms of benign neoplastic disease, has received little palaeopathological or palaeoepidemiological interest largely because of its asymptomatic nature. This is problematic because these tumours are regarded as common occurrences in bioarchaeological contexts, despite there being scant data to support these claims. This investigation presents a palaeoepidemiological enquiry into osteomata. Five hundred ninety individuals from six skeletal assemblages from Poland, dating from the 9th to 17th century, were macroscopically surveyed for osteomata. This was followed by a palaeoepidemiological analysis, looking at sex‐ and age‐specific prevalence. Ninety‐three osteomata were observed in 67 individuals. The sex‐specific prevalence was 13.5% (95% confidence interval [CI]: 9.7–18.1) for males and 11.6% (95% CI 7.9–16.2) for females. The age‐specific prevalence for middle adults was 2.1% (95% CI: 0.6–5.2) and 5.3% (95% CI: 2.5–9.8) for mature adults. The results indicated the prevalence of benign tumours was similar between males and females and seemed to increase with age. This case study adds to a sparse area of palaeo‐oncological research and calls for further future investigation

Malignancy in three medieval Polish osteological collections

This paper presents the archaeological skeletal remains of four adult females presenting with cranial lesions typical of malignant neoplastic disease. The four cases were sourced from three medieval Polish skeletal assemblages: Milicz (12–13th century), Pawłów Trzebnicki (15–16th century), and Gródek nad Bugiem (13–15th century). The observed pathological skeletal changes were evaluated with a comprehensive macroscopic analysis of the skeleton, and radiography of the affected bones. The observed osteolytic lesions were largely limited to the crania and were multiple and varied in size; further internal lesions were revealed with radiography. Three cases were differentially diagnosed as highly consistent with metastatic carcinoma, and the fourth case was differentially diagnosed as typical of multiple myeloma. This report adds to the scant number of palaeopathological examples of malignant neoplasms in Poland and it discusses the possible impact of cancer on medieval lives, as well as possible factors in the occurrence of malignant neoplasms in medieval Poland

Trend in ice moistening the stratosphere – constraints from isotope data of water and methane

Water plays a major role in the chemistry and radiative budget of the stratosphere. Air enters the stratosphere predominantly in the tropics, where the very low temperatures around the tropopause constrain water vapour mixing ratios to a few parts per million. Observations of stratospheric water vapour show a large positive long-term trend, which can not be explained by change in tropopause temperatures. Trends in the partitioning between vapour and ice of water entering the stratosphere have been suggested to resolve this conundrum. We present measurements of stratospheric H_(2)O, HDO, CH_4 and CH_(3)D in the period 1991–2007 to evaluate this hypothesis. Because of fractionation processes during phase changes, the hydrogen isotopic composition of H_(2)O is a sensitive indicator of changes in the partitioning of vapour and ice. We find that the seasonal variations of H_(2)O are mirrored in the variation of the ratio of HDO to H_(2)O with a slope of the correlation consistent with water entering the stratosphere mainly as vapour. The variability in the fractionation over the entire observation period is well explained by variations in H_(2)O. The isotopic data allow concluding that the trend in ice arising from particulate water is no more than (0.01±0.13) ppmv/decade in the observation period. Our observations suggest that between 1991 and 2007 the contribution from changes in particulate water transported through the tropopause plays only a minor role in altering in the amount of water entering the stratosphere

Direct evidence for the magnetic ordering of Nd ions in NdMn2_2Si2_2 and NdMn2_2Ge2_2 by high resolution inelastic neutron scattering

We have investigated the low energy nuclear spin excitations in NdMn$_2$Si$_2$ and NdMn$_2$Ge$_2$ by high resolution inelastic neutron scattering. Previous neutron diffraction investigations gave ambiguous results about Nd magnetic ordering at low temperatures. The present element-specific technique gave direct evidence for the magnetic ordering of Nd ions. We found considerable difference in the process of the Nd magnetic ordering at low temperature in NdMn$_2$Si$_2$ and NdMn$_2$Ge$_2$. Our results are consistent with those of magnetization and recent neutron diffraction measurements

Digital Dilemma 2018

In October 2018 a one-day conference was held at the UCL Institute of Archaeology focussing on the ‘Digital Dilemma’ in biological archaeology —specifically human remains research where the use of digitisation methods have increased exponentially over the last decade while comparatively little discussion of the ethical and legal considerations of these data has taken place. Papers presented at Digital Dilemma 2018 explored the use of digital data in human remains research, discussing both the benefits provided by these data, areas of ethical or methodological concern and suggestions for future research. This paper and the following conference proceedings will discuss this research demonstrating the importance that this Digital Dilemma in archaeology continues to be discussed and considered in future research