Tip dating supports novel resolutions of controversial relationships among early mammals

The estimation of the timing of major divergences in early mammal evolution is challenging due to conflicting interpretations of key fossil taxa. One contentious group is Haramiyida, the earliest members of which are from the Late Triassic. Many phylogenetic analyses have placed haramiyidans in a clade with multituberculates within crown Mammalia, thus extending the minimum divergence date for the crown group deep into the Triassic. A second taxon of interest is the eutherian Juramaia from the Middle-Late Jurassic Yanliao Biota, which is morphologically very similar to eutherians from the Early Cretaceous Jehol Biota and implies a very early origin for therian mammals. Here we apply Bayesian tip-dating phylogenetic methods to investigate these issues. Tip dating firmly rejects a monophyletic Allotheria (multituberculates and haramiyidans), which are split into three separate clades, a result not found in any previous analysis. Most notably, the Late Triassic Haramiyavia and Thomasia are separate from the Middle Jurassic euharamiyidans. We also test whether the Middle–Late Jurassic age of Juramaia is ‘expected’ given its known morphology by assigning an age prior without hard bounds. Strikingly, this analysis supports an Early Cretaceous age for Juramaia, but similar analyses on twelve other mammaliaforms from the Yanliao biota return the correct, Jurassic age. Our results show that analyses incorporating stratigraphic data can produce results very different from other methods. Early mammal evolution may have involved multiple instances of convergent morphological evolution (e.g., in the dentition), and tip dating may be a method uniquely suitable to recognising this due to the incorporation of stratigraphic data. Our results also confirm that Juramaia is anomalous in exhibiting a much more derived morphology than expected given its age, which in turn implies very high rates of evolution at the base of therian mammals

Lattice-point generating functions for free sums of convex sets

Let \J and \K be convex sets in $\R^{n}$ whose affine spans intersect at a single rational point in \J \cap \K, and let \J \oplus \K = \conv(\J \cup \K). We give formulas for the generating function {equation*} \sigma_{\cone(\J \oplus \K)}(z_1,..., z_n, z_{n+1}) = \sum_{(m_1,..., m_n) \in t(\J \oplus \K) \cap \Z^{n}} z_1^{m_1}... z_n^{m_n} z_{n+1}^{t} {equation*} of lattice points in all integer dilates of \J \oplus \K in terms of \sigma_{\cone \J} and \sigma_{\cone \K}, under various conditions on \J and \K. This work is motivated by (and recovers) a product formula of B.\ Braun for the Ehrhart series of \P \oplus \Q in the case where $\P$ and \Q are lattice polytopes containing the origin, one of which is reflexive. In particular, we find necessary and sufficient conditions for Braun's formula and its multivariate analogue.Comment: 17 pages, 2 figures, to appear in Journal of Combinatorial Theory Series

Beneficial and Harmful Agile Practices for Product Quality

There is the widespread belief that Agile neglects the product quality. This lack of understanding how Agile processes assure the quality of the product prevents especially companies from regulated domains from an adoption of Agile. This work aims to identify which Agile Practices contribute towards product quality. Hence, data from a survey study is analyzed to identify Ag-ile Practices which are beneficial or harmful for the quality of the product. From 49 practices that were used in the survey so far, 36 were perceived to have a positive impact on product quality, while four practices were rated as being harmful. The results enrich understanding of how product quality can be achieved in Agile, and support selection of practices to improve quality

Horn antenna with v-shaped corrugated surface

Corrugated shape is easily machined for millimeter wave application and is better suited for folding antenna designs. Measured performance showed ""V'' corrugations and rectangular corrugations have nearly the same pattern beamwidth, gain, and impedance. Also, ""V'' corrugations have higher relative power loss

Can Long-Range Nuclear Properties Be Influenced By Short Range Interactions? A chiral dynamics estimate

Recent experiments and many-body calculations indicate that approximately 20\% of the nucleons in medium and heavy nuclei ($A\geq12$) are part of short-range correlated (SRC) primarily neutron-proton ($np$) pairs. We find that using chiral dynamics to account for the formation of $np$ pairs due to the effects of iterated and irreducible two-pion exchange leads to values consistent with the 20\% level. We further apply chiral dynamics to study how these correlations influence the calculations of nuclear charge radii, that traditionally truncate their effect, to find that they are capable of introducing non-negligible effects.Comment: 6 pages, 0 figures. This version includes many improvement

An investigation of adhesive/adherend and fiber matrix interactions

Research during the report period focused on continued scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) of lap shear samples and flatwise tensile specimens and on the surface characterization of TiO2, Ti 6-4, and Ti powders with particular emphasis on their interaction with primer solutions of both polyphenylquinoxaline and LaRC-13 polyimide. The use of SEM and XPS in the analysis of Ti 6-4 adherend surfaces is described as well as differences in Ti 6-4 surface composition after different chemical pretreatments. Analysis of fractured surfaces is used to established the failure mode. The surface acidity of Ti 6-4 coupons can be established by reflectance visible spectroscopy using indicator dyes

A framework for utility data integration in the UK

In this paper we investigate various factors which prevent utility knowledge from being fully exploited and suggest that integration techniques can be applied to improve the quality of utility records. The paper suggests a framework which supports knowledge and data integration. The framework supports utility integration at two levels: the schema and data level. Schema level integration ensures that a single, integrated geospatial data set is available for utility enquiries. Data level integration improves utility data quality by reducing inconsistency, duplication and conflicts. Moreover, the framework is designed to preserve autonomy and distribution of utility data. The ultimate aim of the research is to produce an integrated representation of underground utility infrastructure in order to gain more accurate knowledge of the buried services. It is hoped that this approach will enable us to understand various problems associated with utility data, and to suggest some potential techniques for resolving them

BSE crisis and food safety regulation: a comparison of the UK and Germany

The BSE crisis represents one of the worst policy disasters experienced by a UK government in recent years. In material terms, it led to the slaughter of 3.3 million cattle and an estimated economic loss of £3.7 billion. In administrative terms, the crisis led to the dissolution of the Ministry of Agriculture, Fisheries and Food (MAFF), an institution that was heavily criticised by the Phillips Inquiry for its lack of openness and transparency. Although far less severe in terms of its economic impact, with estimated losses of between Euro 0.8 and 1.05 billion, the German BSE crisis resulted in extensive political fallout, leading, inter alia, to the resignation of two government ministers. This paper compares the handling of the crisis in the UK and Germany and the regulation put in place in its aftermath. It explores the reasons for the failure of both governments to manage this crisis in a credible, timely and proactive fashion. Examining the institutional contexts in which decisions about scientific evidence on BSE were made, the paper argues that, in both countries, a centralised system, in which government agencies controlled “science for government”, was vulnerable to expert-interest group alliances which undermined the potential for a credible assessment of public health and safety risks. Looking at the policies adopted in the aftermath of these crises, the paper notes that, although being far less affected by BSE, Germany paradoxically adopted far more rigorous measures for the prevention of future incidents, which included the strict administrative separation of the risk assessment and management functions. Our paper concludes that the extent of administrative reforms which are initiated in response to crises is more likely to correspond to that general receptiveness of the political environment to these reforms, than the ‘objective’ impact of the crisis itself