Applications of Cathodoluminescence of Quartz and Feldspar to Sedimentary Petrology

Cathodoluminescence (CL), the emission of visible light during electron bombardment, was first used in sandstone petrology in the mid-1960\u27s. CL techniques are especially useful for determining the origin and source of quartz and feldspar, two of the most common constituents in elastic rocks. CL properties of both minerals are dependent on their temperature of crystallization, duration of cooling, and/or history of deformation. Detrital quartz and feldspar are typically derived from igneous and metamorphic sources and luminesce in the visible range whereas authigenic quartz and feldspar form at low temperatures and do not luminesce. Quantification of luminescent and non-luminescent quartz and feldspar with the scanning electron microscope, electron microprobe, or a commercial CL device can allow for the determination of origin, diagenesis, and source of elastic rocks when used in conjunction with field and other petrographic analyses. Future expansion and documentation of the classifications and causes of CL in these minerals may increase the usefulness of CL techniques in sandstone petrology

Wirkungen von Medienjournalismus auf Journalisten: eine ökonomische Analyse der Nutzung und Wirkung von Medienjournalismus durch/ auf Journalisten anhand qualitativ ausgewerteter Interviews

'Hintergrund der Fragestellung ist die in der Publizistik- und Kommunikationswissenschaft häufig vertretene These, Medienjournalismus könne zur Qualitätssicherung des Journalismus beitragen. Diese Funktion kann der Medienjournalismus aber nur erfüllen, wenn Journalisten ihn wahrnehmen und wenn Medienjournalismus auf sie wirkt.' ... 'Mit Hilfe des Rational-Choice-Ansatzes wird nach entsprechenden Situationen gesucht. Dem einzelnen Journalisten wird dabei rationales Verhalten unterstellt, d.h. er handelt im eigenen Interesse und auf seinen eigenen Vorteil bedacht. Unter Berücksichtigung der ihm entstehenden Kosten wird er in einer Entscheidungssituation die ihm vorteilhafter erscheinende Alternative wählen. Im Gegensatz zur systemtheoretischen Perspektive kommt bei diesem Ansatz ein methodologischer Individualismus zum Tragen, bei dem der einzelne Journalist in Entscheidungssituationen betrachtet wird.' ... Es handelt sich 'um eine explorative Studie, die den Journalisten als Rezipient von Medienjournalismus sieht und nach seiner Wirkung auf diese journalistischen Rezipienten fragt.' ... 'Mittels einer qualitativen Leitfaden-Befragung wurden insgesamt 29 Journalistinnen und Journalisten aus ganz Deutschland befragt.' Der Autor kommt zu dem Ergebnis, 'dass Situationen, in denen Medienjournalismus eine qualitätssichernde Funktion wirklich erfüllen kann, rar sind.' (HS2

Data Scientists: A New Faction of the Transnational Field of Statistics

Big Data analytics and related methods introduce new possibilities for the generation of official statistics, but also raise the question of whether national statisticians can continue to claim the legitimate authority to generate knowledge of the state. Drawing on a collaborative ethnography of European official statistics, we follow the politics of method where statisticians position themselves in relation to data scientists. We show that data scientists do not replace national statisticians but that both professional groups are relationally reconfigured in material-semiotic practices that cut across national organisations, such as experiments, demonstrations, job descriptions, and transnational negotiations. Through the tentative definition of the ‘iStatistician’, Big Data methodologies reconfigure the f

Protein O-Mannosylation in the Murine Brain: Occurrence of Mono-O-Mannosyl Glycans and Identification of New Substrates

Protein O-mannosylation is a post-translational modification essential for correct development of mammals. In humans, deficient O-mannosylation results in severe congenital muscular dystrophies often associated with impaired brain and eye development. Although various O-mannosylated proteins have been identified in the recent years, the distribution of O-mannosyl glycans in the mammalian brain and target proteins are still not well defined. In the present study, rabbit monoclonal antibodies directed against the O-mannosylated peptide YAT(α1-Man)AV were generated. Detailed characterization of clone RKU-1-3-5 revealed that this monoclonal antibody recognizes O-linked mannose also in different peptide and protein contexts. Using this tool, we observed that mono-O-mannosyl glycans occur ubiquitously throughout the murine brain but are especially enriched at inhibitory GABAergic neurons and at the perineural nets. Using a mass spectrometry-based approach, we further identified glycoproteins from the murine brain that bear single O-mannose residues. Among the candidates identified are members of the cadherin and plexin superfamilies and the perineural net protein neurocan. In addition, we identified neurexin 3, a cell adhesion protein involved in synaptic plasticity, and inter-alpha-trypsin inhibitor 5, a protease inhibitor important in stabilizing the extracellular matrix, as new O-mannosylated glycoproteins

What does the rho-meson do? In-medium mass shift scenarios versus hadronic model calculations

The NA60 experiment has studied low-mass muon pair production in In-In collisions at $158 {\rm AGeV}$ with unprecedented precision. With these results there is hope that the in-medium modifications of the vector meson spectral function can be constrained more thoroughly than before. We investigate in particular what can be learned about collisional broadening by a hot and dense medium and what constrains the experimental results put on in-medium mass shift scenarios. The data show a clear indication of considerable in-medium broadening effects but disfavor mass shift scenarios where the $\rho$-meson mass scales with the square root of the chiral condensate. Scaling scenarios which predict at finite density a dropping of the $\rho$-meson mass that is stronger than that of the quark condensate are clearly ruled out since they are also accompanied by a sharpening of the spectral function.Comment: Proceeding contribution, Talk given by J. Ruppert at Workshop for Young Scientists on the Physics of Ultrarelativistic Nucleus-Nucleus Collisions (Hot Quarks 2006), Villasimius, Sardinia, Italy, 15-20 May 2006. To appear in EPJ

Interpretation of Recent SPS Dilepton Data

We summarize our current theoretical understanding of in-medium properties of the electromagnetic current correlator in view of recent dimuon data from the NA60 experiment in In(158 AGeV)-In collisions at the CERN-SPS. We discuss the sensitivity of the results to space-time evolution models for the hot and dense partonic and hadronic medium created in relativistic heavy-ion collisions and the contributions from different sources to the dilepton-excess spectra.Comment: To appear in the proceedings of the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (Quark Matter 2006) v2: references added, minor typos correcte

Functional generalized additive models

We introduce the functional generalized additive model (FGAM), a novel regression model for association studies between a scalar response and a functional predictor. We model the link-transformed mean response as the integral with respect to t of F{X(t), t} where F(·, ·) is an unknown regression function and X(t) is a functional covariate. Rather than having an additive model in a finite number of principal components as by Müller and Yao (2008), our model incorporates the functional predictor directly and thus our model can be viewed as the natural functional extension of generalized additive models. We estimate F(·, ·) using tensor-product B-splines with roughness penalties. A pointwise quantile transformation of the functional predictor is also considered to ensure each tensor-product B-spline has observed data on its support. The methods are evaluated using simulated data and their predictive performance is compared with other competing scalar-on-function regression alternatives. We illustrate the usefulness of our approach through an application to brain tractography, where X(t) is a signal from diffusion tensor imaging at position, t, along a tract in the brain. In one example, the response is disease-status (case or control) and in a second example, it is the score on a cognitive test. The FGAM is implemented in R in the refund package. There are additional supplementary materials available online. © 2013 American Statistical Association, Institute of Mathematical Statistics, and Interface Foundation of North America