Examining the case for the use of the Tertiary as a formal period or informal unit

The ‘Tertiary’, omitted from IUGS-approved timescales since 1989, is still in common use. With the recent re-instatement of the Quaternary as a formal unit, the question arises as to whether the Tertiary too should be reinstated as a formal period, with the ‘Paleogene’ and ‘Neogene’ being downgraded to sub-periods. This paper presents arguments for and against this proposal, stemming from discussions by members of the Geological Society Stratigraphy Commission. It is intended to stimulate discussion of the topic in the wider community

Comparison of clustering techniques for determining compositional units on Mercury from MESSENGER spectral observations.

The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) obtained spectra of much of the surface of Mercury during the rst two MESSENGER ybys of the planet. The resulting dataset is composed of several hundred re ectance spectra that have not yet been corrected for any eect due to observing geometry or to surface material phase curves. Our hypothesis is that the separation of surface signal from other contributions can be eciently performed by the use of statistical techniques. We adopt principal component and clustering analyses to identify and characterize spectral units along the MASCS ground tracks. In order to extract the spectral shapes of the primary surface components exposed in the surface area an- alyzed, we applied an R-mode factor analysis, aiming to nd an eigenvector set that minimizes data covariance. Identication of the dierent components and their abundances is accom- plished by principal component analysis together with an evaluation of the eigenvectors and eigenvalues of the covariance matrix (also called covariance matrix decomposition). A compar- ison of the results using only the near-infrared (NIR) and visible (VIS) portions of the spectra indicates that the NIR spectral range is carrying less information than the VIS portion. We also nd that the eigenvectors are essentially unchanged if the full wavelength range is selected (VIS+NIR) rather than limiting observations to the VIS range. The full-range analysis shows that seven eigenvectors are needed to reconstruct the original spectrum to within the level of variability associated with the observational data. Each spectral eigenvector can be regarded as a representative of a distinct spectral class that varies in spatial abundance along the track. The rst eigenvector always displays a strong positive or \red" slope, probably strongly linked to uncorrected eects associated with viewing geometry variations, and all eigenvectors show distinctive spectral signatures. Concentration coecients, or eigenvector abundances, indicate that spectral units show marked geographical variation and a strong correlation with surface units mapped by MESSENGER's Mercury Dual Imaging System (MDIS). Because we do not photometrically correct the data, we apply a decorrelation technique (Mahalanobis transforma- tion) to remove dependence on observation angle in the retrieved concentration coecients. We obtain a set of transformed variables that no longer are eigenvector concentration coecients or abundances. These variables therefore cannot be used to linearly reconstruct the original dataset via inversion of the covariance matrix decomposition transformation. The Mahalanobis decorrelation removes the variation directly linked to viewing geometry variations, but it re- tains the eigenvector abundance variation along each track that can be used to classify the measurements and to identify spectral units. Those coecients are analyzed through three dierent clustering techniques: hierarchical, K-means and self-organizing maps. We evaluate the optimal partition of our set by means of dierent validation criteria, and we compare the output from the dierent algorithms. At the same time, we make use of newly available high- temperature spectra from our Planetary Emissivity Laboratory to assist in the identication of the components of each unit. Application to data from the rst yby provides us with condence in the ability of these techniques to extract physical properties of surface materials

Compositional units on Mercury from MESSENGER spectral observations: comparison of clustering techniques

The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) obtained spectra of much of the surface of Mercury during the first two MESSENGER flybys of the planet [1]. The dataset have not been corrected for any effect due to observing geometry, but only converted to reflectance [2]. The characterization of spectral units is performed by statistical techniques. In order to extract the spectral shapes of the primary surface components exposed in the surface area analyzed, we applied an R-mode factor analysis [3] [4]. That leads to the evaluation of the eigenvectors of the covariance matrix and their abundances along the track. The results indicates that the NIR spectral range is carrying less information than the VIS portion and that the eigenvectors are unchanged if the full wavelength range is selected rather than limiting observations to the VIS. The analysis shows that seven eigenvectors are needed to reconstruct the original data, where each eigenvector can be regarded as a representative of a spectral class that varies in abundance along the track. The first eigenvector always displays a strong positive or “red” slope, carrying the effects associated to the viewing geometry and all eigenvectors show distinctive spectral signatures. The eigenvector abundances show marked geographical variation and a strong correlation with surface units mapped by MESSENGER’s Mercury Dual Imaging System (MDIS). We apply a decorrelation technique (Mahalanobis transformation [5]) to remove dependence on observation angle in the retrieved eigenvector abundances and then used the corrected abundances to classify or cluster the measurements and to identify spectral units. We used three clustering techniques and then we compare the output from the algorithms. At the same time, we make use of newly available high-temperature spectra from our Planetary Emissivity Laboratory [6] to assist in the identification of the components of each unit. Application to data from the first flyby provides us with confidence in the ability of these techniques to extract physical properties of surface materials

Location choice for direct foreign investment in new hospitals in China by using ANP and TOPSIS

Location choice, Foreign direct investment (FDI), Hospital, China, ANP, TOPSIS,

Implante de placa de silicone na substituição parcial da parede traqueal em caninos The sylicon slab implant in substitution of partial canine tracheal wall

Foram operados seis cães, SRD, no intuito de testar a viabilidade do uso de placa de silicone em casos de perda parcial da parede traqueal. Esses animais, submetidos a anestesia volátil, sofreram remoção de um terço da circunferência de três anéis traqueais a nível da região cervical média. No local dessa abertura foi implantada uma placa de silicone com dimensões compatíveis à mesma, fixada a cartilagem traqueal circunvizinha. Os cães foram observados num período de trinta dias, ao final do qual foram realizadas as necropsias com avaliação macro e microscópica do local do implante. Foi detectada a substituição do tecido removido, assim como a sua epitelização.<br>Six dogs were submitted to an operation to test the viability of sylicon slab in partial replecement of tracheal wall. These animais were anesthetized and had removed a third part with compatible dimension of the circunference of three tracheal rings at mid cervical region. At this place a sylicon slab was implanted and fixed to the surrounding tracheal cartilage. The dogs were observed during thirty days. At post morten, they were evalueted by gross and microscopic examination. It was detected the tissue replacement and the growing of the epithelium

A New Analysis of Mars ‘‘Special Regions’’: Findings of the Second MEPAG Special Regions Science Analysis Group (SR-SAG2)

A committee of the Mars Exploration Program Analysis Group (MEPAG) has reviewed and updated the description of Special Regions on Mars as places where terrestrial organisms might replicate (per the COSPAR Planetary Protection Policy). This review and update was conducted by an international team (SR-SAG2) drawn from both the biological science and Mars exploration communities, focused on understanding when and where Special Regions could occur. The study applied recently available data about martian environments and about terrestrial organisms, building on a previous analysis of Mars Special Regions (2006) undertaken by a similar team. Since then, a new body of highly relevant information has been generated from the Mars Reconnaissance Orbiter (launched in 2005) and Phoenix (2007) and data from Mars Express and the twin Mars Exploration Rovers (all 2003). Results have also been gleaned from the Mars Science Laboratory (launched in 2011). In addition to Mars data, there is a considerable body of new data regarding the known environmental limits to life on Earth—including the potential for terrestrial microbial life to survive and replicate under martian environmental conditions. The SR-SAG2 analysis has included an examination of new Mars models relevant to natural environmental variation in water activity and temperature; a review and reconsideration of the current parameters used to define Special Regions; and updated maps and descriptions of the martian environments recommended for treatment as ‘‘Uncertain’’ or ‘‘Special’’ as natural features or those potentially formed by the influence of future landed spacecraft. Significant changes in our knowledge of the capabilities of terrestrial organisms and the existence of possibly habitable martian environments have led to a new appreciation ofwhere Mars Special Regions may be identified and protected. The SR-SAG also considered the impact of Special Regions on potential future human missions to Mars, both as locations of potential resources and as places that should not be inadvertently contaminated by human activity