Barremian and Aptian (Cretaceous) sharks and rays from Speeton, Yorkshire, north-east England

Bulk sampling of a number of horizons within the upper part of the Speeton Clay Type section has produced teeth and other remains of sharks and rays from several poorly studied horizons. At least 10 shark and two ray species were recorded, with two sharks, Pteroscyllium speetonensis and Palaeobrachaelurus mitchelli, being described as new. The oldest occurrences of the family Anacoracadae and the genus Pteroscyllium, as well as the youngest occurrence of the genus Palaeobrachaelurus, were recorded. The palaeoenvironmental significance of the faunas is briefly discussed

WTS-1 b

The end of the twentieth century saw a revolution in our knowledge of planetary systems. The detection of the first extrasolar planet in 1992 marked the beginning of a modern era and changed our idea of planets and planetary systems. The discoveries continue rapidly and reveal an extraordinary diversity of planetary systems and physical properties of the exoplanets, raising new questions in the field of planetary science. So far, more than 800 extrasolar planets have been detected, spanning a wide range of masses from a few Earth masses to a few tens of Jupiter masses. This Ph.D. Thesis is devoted to the confirmation via radial velocity follow-up of the candidate planets detected by the WFCAM Transit Survey (WTS), which is an on-going photometric monitoring campaign using the Wide Field Camera on the United Kingdom Infrared Telescope at Mauna Kea (Hawaii, USA). The WTS and the present work were supported by the RoPACS (Rocky Planets Around Cool Stars) group, a Marie Curie Initial Training Network funded by the Seventh Framework Programme of the European Commission. Since the WTS was primarily designed to find planets transiting M-dwarf stars, the observations are obtained in the J-band (1.25 micron). This wavelength is near to the peak of the spectral energy distribution of a typical M-dwarf. Simulations show that operating in the J-band reduces the effects of stellar variability, which became important at optical wavelengths in cool stars. The J-band light curves that show a periodic drop and pass all the selection criteria, progress to the candidate confirmation phase. After a transit depth consistency check performed with i'-band observations, intermediate resolution spectra enable to rule out false-positive eclipsing binaries scenarios. Finally, high-resolution spectroscopic follow-up is performed to confirm, by the radial velocity method, the planetary nature of the stellar companion detected by the WTS. The spectra employed in this phase were observed with the High Resolution Spectrograph (HRS) housed in the basement of the 9.2-m Hobby-Eberly Telescope (HET) in Texas, USA. The pipeline for the reduction and analysis of the HET spectra has been created. Debug, optimization and test of the whole procedure were performed observing several target stars with different apparent magnitude and spectral type. These observations allowed to estimate the precision on the velocity measures for different targets. Errorbars of 10 m/s are expected for solar type stars of magnitude up to mV=10 and SNR of the observed spectra >150. Spectra with a SNR of 30 can be measured for faint (mV=14) M stars, leading to a final radial velocity uncertainty of about 60 m/s. Furthermore, a technical problem occurring under given instrumental configurations could be identified and fixed, removing a possible source of systematic from any later observation. Finally, the zero-point offset with respect to the HARPS data was computed allowing the comparison of the HET measures with those related to any other instruments involved in radial velocity follow-up. The radial velocities computed from the HET high-resolution spectra allowed to confirm the detection of the first two extrasolar planet performed by the WTS. WTS1 b is a 4 MJ planet orbiting in 3.35 days a late F-star with possibly slightly sub-solar metallicity. With a radius of 1.49 RJ, it is the third largest planet of the known extrasolar planets in the mass range 3-5 MJ. Its unusual large radius can not be explained within the standard evolution models, even considering the strong radiation that the planet receives from the parent star. Ohmic heating could be a possible mechanism able to bring energy in the deeper layers of WTS1 b and hence explaining its radius anomaly. WTS2 b is instead a 1 MJ planet orbiting an early K-star in about 1 day only. The measure of its secondary eclipses in the Ks-band will allow to study a highly irradiated planet around a cool star, cooler than many of the currently known very hot-Jupiters host star. This will provide an insight to the effect of the stellar spectrum on the composition and structure of hot-Jupiter atmospheres. Beyond the RoPACS program, the pipeline has been employed in the radial velocity follow-up of the white dwarf NLTT 5306, confirming the presence of a brown dwarf companion of 56 MJ orbiting its host star in 102 minutes, the shortest period ever observed in such systems. The discoveries of WTS1 b and WTS2 b demonstrate the capability of WTS to find planets, even if it operates in a back-up mode during dead time on a queue-schedule telescope and despite of the somewhat randomised observing strategy. Moreover, the two new discovered planets are hot-Jupiters orbiting an F-star and a K-star. Both are hotter than an M-dwarf, the main target sample of the WTS. As described in Kovacs et al. (2012, MNRAS submitted), no planets around M-dwarf stars monitored by the WTS (mV<17) with period shorter than 10 days have been found. According to these results, the upper limit of the very hot-Jupiter planetary occurrence around M-stars can be estimated. The resulting value of 0.017 is a stricter constraint than the one derived for the Kepler M-dwarfs sample (0.04).Ende des zwanzigsten Jahrhunderts erlebte unser Verständnis von Planetensystemen eine Revolution. Die Entdeckung des ersten extrasolaren Planeten im Jahr 1992 markierte den Beginn einer ära und veränderte unser Bild von Planeten und Planetensystemen grundlegend. In den darauf folgende Jahren wurde viele weitere Detektionen erzielt, die eine ausserordentliche Vielfalt an Planetensystemen mit unterschiedlichen physikalischen Eigenschaften aufdeckten welche fortan neue Fragen auf dem Gebiet der lanetologie aufwerfen. Bis heute wurden mehr als 800 extrasolare Planeten nachgewiesen die einen weiten Bereich an Massen abdecken, der von wenigen Erdmassen bis zu ein paar Dutzend Jupitermassen reicht. Die vorliegende Ph.D. Thesis behandelt die Bestätigung von Planetenkandidaten mit Hilfe von Radialgeschwindigkeitsmessungen. Gefunden wurden die Kandidaten im Rahmen des WFCAM Transit Surveys (WTS) - einer photometrische Suchkampagne mit der Wide Field Camera am United Kingdom Infrared Telescope auf dem Mauna Kea (Hawaii, USA). Der WTS und diese Arbeit wurden im Rahmen des siebten Programms der Europäischen Kommission von der RoPACS (Rocky Planets Around Cool Stars) Gruppe, einem Marie Curie Initial Training Network, unterstützt. Da der WTS in erster Linie konzipiert wurde, um Planeten um M-Zwerge zu finden, wurden die Beobachtungen im J- Band bei ca. 1.25 micron aufgenommen. Diese Wellenlänger ist in der Nähe des Maximum der spektralen Energiverteilung eines M-Zwerges. Simulationen zeigen, dass Beobachtungen im J-Band die Effekte von stellarer Variabilität verringern, welche stärker im optischen Spektrum von kühlen Sternen auftreten. Die J-Band Lichtkurven, die einen periodischen Helligkeitsabfall zeigen und die Selektionskriterien erfüllen, wurden in der folgenden Bestätigungs-Phase weiter untersucht. Nach einem Konsistenz-Check der Transittiefe mit Hilfe von photometrischen Nachbeobachtungen im i'-Band wurden Fehldetektionen in Form von Bedeckungsveränderlichen mit Spektren mittlerer Auflösung ausgeschlossen. Danach wurden hochauflösende Spektren aufgenommen, um die WTS-Kandidaten mit der Radialgeschwindigkeits-Methode als Planeten zu bestätigen. Diese hochauflösenden Spektren wurden mit dem High Resolution Spectrograph am 9.2-m Hobby-Eberly Telescope (HET) in Texas, USA, aufgenommen. Die Daten-Analyse Pipeline für die Auswertung der HET Spektren wurde im Rahmen dieser Arbeit entwickelt. Fehlersuche, Optimierungen und Tests der gesamten Prozedur wurden mit Hilfe von Beobachtungen von mehreren Sternen mit unterschiedlicher scheinbaren Helligkeit und unterschiedlichem Spektraltypen durchgeführt. Dies erlaubte es, die Präzision der Radialgeschwindigkeitsmessungen für unterschiedliche Sterne zu bestimmen. Demnach sind Fehlerbalken von 10 m/s für sonnenähnliche Sterne mit Helligkeiten bis mV=10 und SNR der beobachteten Spektren von >150 zu erwarten. Spektren mit einem SNR von 30 können für schwache M-Sterne (mV=14) gemessen werden, für welche eine Radialgeschwindigkeitsgenauigkeit von 60 m/s erreicht wird. Des weiteren wurde ein technisches Problem identifiziert und behoben, welches für bestimmte Konfigurationen des Spektrographen auftritt. Damit wurde eine systematische Fehlerquelle für alle folgenden Beobachtungen eliminiert. Schlussendlich wurde ein Nullpukts-Offset für Daten des HARPS-Spektrographen bestimmt, welcher es erlaubt, die HET Daten mit Messungen von anderen Spektrographen, die im Prozess der Nachbeobachtungen beteiligt waren, zu kombinieren. Die Radialgeschwindigkeiten, welche aus den hochau flösenden HET Spektren bestimmt wurden, haben zur Bestätigung der ersten beiden Detektionen von extrasolaren Planeten im WTS geführt. WTS1 b ist ein 4 MJ Planet welcher in 3.35 Tagen einen späten F-Stern mit möglicherweise geringfügig subsolarer Metallizität umkreist. Mit einem Radius von 1.49 RJ ist er der drittgrösste von allen bisher gefundenen extrasolaren Planet im Massenbereich von 3-5 MJ. Der ungewöhlich grosse Radius kann nicht durch die etablierten Standardentwicklungstheorien erklärt werden, selbst wenn man die starke Einstrahlung berücksichtigt, die der Planet von seinem Mutterstern empfängt. Der Mechanismus des Ohm'schen Heizens könnte Energie in die tieferen Schichten von WTS1 b bringen und damit den anomalen Radius erklären. WTS2 b ist ein 1 MJ Planet, welcher einen frühen K-Sterne in etwa 1 Tag umrundet. Messungen der sekundären Bedeckung im Ks-Band werden es erlauben, die thermische Strahlung dieses besonderen Planeten zu messen, der Einfluss der starken Einstrahlung seines nahen Muttersterns steht, welcher aber deutlich kühler ist, als die Muttersterne anderer bekannter Hot Jupiter. Dies wird darüber Aufschluss geben, welchen Einfluss das stellare Spektrum auf die Zusammensetzung und den Aufbau von Hot Jupiter Atmosphären hat. Zusäzlich zum RoPACS Programm wurde die in dieser Arbeit entwickelte Daten-Analyse Pipeline für die Auswertung von Radialgeschwindigkeits Beobachtungen des Weissen Zwerg Sterns NLTT 5306 verwendet, welche die Existenz eines Braunen Zwerges mit 56 MJ bestätigte, der den Weissen Zwerg in nur 102 Minuten umkreist. Dies ist die kürzeste Periode, die bislang in solchen Systemen beobachtet wurde. Die Entdeckungen von WTS1 b und WTS2 b zeigen, dass der WTS Planeten finden kann, und das obwohl er als back-up Programm für schlechte Beobachtungsbedingen betrieben wird was zu einer mehr oder minder zufälligen Abfolge der Beobachtungen führt. Die beiden detektierten Planeten sind sogenannte Hot-Jupiter die einen F- bzw. einen K-Stern umrunden. Diese Sterne sind heisser als M-Zwerge, welche das Hauptziel des WTS sind. Wie in Kovacs et al. (2012, MNRAS submitted) beschrieben, wurden bislang im WTS keine Planeten um M-Zwerge mit Helligkeiten von mV <17 und Perioden kürzer als 10 Tagen gefunden. Aufgrund dieser Ergebnisse, konnte eine Obergrenze für die Planetenhäugkeit von Jupiterähnlichen Planeten um M-Zwerge bestimmt werden. Diese Obergrenze liegt bei 0.017 und ist damit präziser als die zuvor auf dem Kepler M-Zwerg Datensatz bestimmte Grenze von 0.04

High resolution spectroscopy of the three dimensional cosmic web with close QSO groups

We study the three-dimensional distribution of matter at z~2 using high resolution spectra of QSO pairs and simulated spectra drawn from cosmological hydro-dynamical simulations. We present a sample of 15 QSOs, corresponding to 21 baselines of angular separations evenly distributed between ~1 and 14 arcmin, observed with the Ultraviolet and Visual Echelle Spectrograph (UVES) at the European Southern Observatory-Very Large Telescope (ESO-VLT). The observed correlation functions of the transmitted flux in the HI Lya forest transverse to and along the line of sight are in agreement, implying that the distortions in redshift space due to peculiar velocities are relatively small and - within the relatively large error bars - not significant. The clustering signal is significant up to velocity separations of ~300 km/s, corresponding to about 5 h^{-1} comoving Mpc. Compatibility at the 2 sigma level has been found both for the Auto- and Cross-correlation functions and for the set of the Cross correlation coefficients. The analysis focuses in particular on two QSO groups of the sample. Searching for alignments in the redshift space between Lya absorption lines belonging to different lines of sight, it has been possible to discover the presence of a wide HI structures extending over about ten Mpc in comoving space, and give constraints on the sizes of two cosmic under-dense regions in the intergalactic medium.Comment: Accepted by MNRAS, version matching the published on

Otolithes de poissons pliocènes du sud-est de la France

Otoliths collected from nine localities in the Lower and Middle Pliocene blue marls of southern France revealed the presence of 118 teleost taxa, including 80 named species. Three new species are introduced: Pseudophichthys escaravatierensis, "genus Bythitinorum" vonhachti and Cepola neogenica. The associations studied belong to five different biozones of planktonic foraminifera in the Lower and Middle Pliocene. The relationships of these Pliocene teleost faunas to the Tortonian and Recent Mediterranean faunas are analysed. Because major problems exist in matching otolith-based species with those erected for osteological material from Messinian localities, our comparisons are based exclusively on data obtained from the otoliths. Fifty of our 80 identified species appear only in the Pliocene. This indicates that at the beginning of the Piocene, the Mediterranean realm was subject to extensive faunal replacement. All the studied associations indicate higher temperatures than those of the present day Mediterranean. In the studied area, the associations from the basal Pliocene (Spaeroidinellopsis Acme-zone) at Saint-Martin-du-Var clearly indicate a bathyal environment, corresponding to depths of 300-500 m or even more. Ascending the stratigraphic column, the successive associations in the Pliocene rias of Southeastern France indicate decreasing depths, corresponding to the progressive filling of these basins. In the studied area, data on the teleosts of the terminal Pliocene are lacking, but faunas of this age are known from Southern Italy. They show that the Paleomediterranean fauna, which was substantially modified at the beginning of the Pliocene, appears near the end of this period as a warm water fauna, trapped in a basin where deterioration of climatic conditions led progressively to extinction. The Recent bathyal fauna of the Mediterranean appears extremely impoverished, but the littoral fauna conserves certain aspects of warmer waters, as is apparent in the prolific evolution of gobiids, labrids and blenniids

Révision de quelques Odontaspididae (Neoselachii: Lamniformes) du Paléocène et de l'Eocène du Bassin de la mer du Nord

The revision of some Odontaspididae species from the Paleocene and the Eocene of the North sea Basin has clarified the generic status of some of them and to precise their dental morphologies. A species from the Lutetian of Belgium, Carcharias sp., can be considered as the first representative of the lineage leading to the Recent species C. taurus. Three new genera are described: Brachycarcharias nov. gen. (Lutetian of Belgium), Orpodon nov. gen. (Selandian of Belgium) and Sylvestrilamia nov. gen. (Ypresian of England). The validity of the genus Hypotodus is confirmed and it is recommended that the poorly defined species hopei is abandoned in favour of the species verticalis in order to avoid confusion

An Exploratory Study Examining Interprofessional Collaboration Between Occupational Therapy and Physical Therapy Practitioners and Students

Purpose: The purpose of this research was to explore the relationship between occupational therapy and physical therapy students and practitioners. Historically there has been limited research conducted that pertains specifically to the interprofessional collaboration of occupational and physical therapy students and practitioners. For the purposes of this study the researchers examined the relationships between occupational and physical therapy students, the relationships between practicing occupational therapists and physical therapists, and differences and similarities of their relationships with respect to variables thought to impact interprofessional collaboration. Methods: A non-experimental survey research design was used to gather and analyze information from the participants. All of the participants completed a demographic survey which sought information pel1aining to variables related to interprofessional collaboration such as time spent with other profession, physical environment of departments, interprofessional education, etc. Students completed the Readiness for Interprofessional Learning Scale, a survey with questions pertaining to their readiness to learn about interprofessional collaboration. Practitioners completed the Index of Interdisciplinary Collaboration, a survey intended to gather information regarding the effectiveness and extent of collaboration between therapists. Six-hundred and thirty-six participants completed the survey and included 305 occupational therapy students COTS), 256 physical therapy students (PTS), 47 occupational therapists, and 28 physical therapists. Following data collection, descriptive and inferential analyses of data were completed. Conclusions: Relationships were discovered between OTS and PTS readiness for interprofessional learning and gender, time spent with other profession, class size, degree sought, and physical distance between occupational and physical therapy departments. Relationships were also found between the therapists\u27 extent and effectiveness of interprofessional collaboration and age, work experience, time spent with the other profession, and physical distance between occupational and physical therapy offices. Greater readiness for interprofessional learning was demonstrated by OTS when compared to PTS. There was no difference for extent and effectiveness of intel-professional collaboration between occupational and physical therapists

Agents of Change in Promoting Reflective Abstraction: A Quasi-Experimental, Study on Limits in College Calculus

We measured student performance on the concept of limit by promoting reflection through four agents of change: instructor, peer, curriculum and individual. It is based on Piaget’s four constructs of reflective abstraction: interiorization, coordination, encapsulation, and generalization, and includes the notion of reversal, as refined into a construct by Dubinsky. Our quasi-experimental study examined the performance of two sections of first-semester calculus students at a midwestern community college. Scores by students in the experimental section were significantly higher than scores by students in the control traditional section on a posttest of limits. A deeper examination of a three-tiered subgroup showed the reflective abstraction section had moderate effect size on mathematical knowledge and strategic knowledge and a large effect size on explanation.

Hybodont sharks of the English Bathonian and Callovian (Middle Jurassic).

Recent bulk sampling and study of museum collections has revealed a high diversity of hybodont sharks from the English Bathonian, with 15 species being recognised. In addition, study of dental and skeletal material from the English Callovian has allowed the diagnosis of a new genus and species, Planohybodus peterboroughensis gen. et sp. nov., allowing the Bathonian species Hybodus grossiconus Agassiz to be referred to Planohybodus. Two additional new genera, Secarodus and Frangerodus, are erected for the Bathonian taxa Hybodus polyprion Agassiz and Strophodus lingualis Woodward, respectively. Egertonodus duffini sp. nov. is described and the diagnosis of Egertonodus based on dental material is discussed. The previously unrecorded Hybodus sp., Parvodus sp., and Lonchidion sp. are recognised but left in open nomenclature. Asteracanthus medius (Owen) is recorded in the British Bathonian for the first time, and the status of Bathonian nominal species of Asteracanthus are assessed. Bathonian hybodonts showed great diversity in trophic ecology and many of the species are specific to particular palaeoenvironments

Sharks of the order Carcharhiniformes from the British Coniacian, Santonian and Campanian (Upper Cretaceous).

Bulk sampling of phosphate-rich horizons within the British Coniacian to Campanian (Upper Cretaceous) yielded very large samples of shark and ray teeth. All of these samples yielded teeth of diverse members of the Carcharhiniformes, which commonly dominate the fauna. The following species are recorded and described: Pseudoscyliorhinus reussi (Herman, 1977) comb. nov., Crassescyliorhinus germanicus (Herman, 1982) gen. nov., Scyliorhinus elongatus (Davis, 1887), Scyliorhinus brumarivulensis sp. nov., ? Palaeoscyllium sp., Prohaploblepharus riegrafi (Müller, 1989) gen. nov., ? Cretascyliorhinus sp., Scyliorhinidae inc. sedis 1, Scyliorhinidae inc. sedis 2, Pteroscyllium hermani sp. nov., Protoscyliorhinus sp., Leptocharias cretaceus sp. nov., Palaeogaleus havreensis Herman, 1977, Paratriakis subserratus sp. nov., Paratriakis tenuis sp. nov., Paratriakis sp. indet. and ? Loxodon sp. Taxa belonging to the families ?Proscylliidae, Leptochariidae, and Carcharhinidae are described from the Cretaceous for the first time. The evolutionary and palaeoecological implications of these newly recognised faunas are discussed