A multichannel detector array with 768 pixels developed for electron spectroscopy

Langstaff, David; Chase, T., (2007) 'A multichannel detector array with 768 pixels developed for electron spectroscopy', Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 573(1-2) pp.169-171 RAE2008

Étude de faisabilité pour une mesure fiable de la mobilité après fracture du membre inférieur chez l'enfant

Introduction : Les fractures du membre inférieur (MI) de l'enfant traitées par immobilisation plâtrée engendrent une modification significative de la mobilité exacerbée en cas d'obésité. L'accéléromètre est un outil d'évaluation du degré d'activité physique (AP) de l'enfant scientifiquement validé. Il n'a jamais fait l'objet d'étude chez un enfant ayant souffert d'une fracture du MI. Le but de ce travail était d'identifier les problèmes dans l'utilisation d'un accéléromètre comme moyen de mesure de l'AP après fracture nécessitant une décharge du MI. Une adaptation de la réhabilitation post-traumatique en fonction du BMI pourrait alors être proposée. Méthode : Identification d'enfants âgés de 8 et 15 ans, victimes d'une fracture du membre inférieur, consultant aux urgences de l'Hôpital de l'Enfance d'octobre 2013 à mai 2014 et nécessitant une décharge post-traumatique. Etaient exclus les enfants polytraumatisés ou souffrants d'un déficit mental. Données pré-requises des patients: âge, poids, taille, sexe, mécanisme de l'accident, type de fracture et traitement. Proposition de port d'un Actiwatch® Spectrum au poignet et cheville pour la période de remobilisation en décharge. Identification des avantages et problèmes liés à l'usage de l'appareil durant les premiers 30 jours de la période de réhabilitation. Importance : L'absence totale d'étude sur la mobilité post-fracture, la complexité des problèmes liés à la marche en décharge, les contraintes de l'immobilisation plâtrée et la prévalence grandissante de l'obésité pédiatrique justifient la recherche d'un moyen fiable pour quantifier la mobilité d'un enfant en décharge après traumatisme du MI. Résultats : Sur 43 fractures du MI traitées à l'HEL durant la période de l'étude, 13 enfants identifiés, dont 1 exclu pour maladie psychiatrique, 1 refus de participation, 2 transferts immédiats, 2 non inclus pour causes pratiques. Sept garçons âgés de 11 à 16 ans ont accepté le port de l'Actiwatch® pour une durée variant entre 7 et 27 jours (moyenne 15). Nombre d'activités (NA) médians de 5 enfants: 171,79 ±105,37 [cpm]* à J1 et 219,48 ±145,52 [cpm] à J5. NA totales médianes sur 24h : 114'072±44'791 [cpm] à J1 et 234'452 ±134'775 [cpm] à J5. Une dynamique de regain de mobilité est mise en évidence avec intensités maximales et minimales du nombre d'activités pour chacun. La médiane du temps de sommeil des 5 enfants était de 716± 45,5 [mn]. Les problèmes rencontrés ont été d'ordre mécanique (Un Actiwatch® fut défectueux), d'ordre pratique (un perdu et rendu tardivement, un port intermittent, une réaction allergique au bracelet à 4j de port). Conclusions La compliance à l'utilisation de l'Actiwatch® sur toute la durée de la décharge n'était pas optimale. La mobilité moyenne des enfants était objectivable de par leur dynamique, leur intensité maximale et minimale et comparables vis-à-vis de certaines études. Une différence avec les sujets en surpoids est observable. La durée de sommeil de chaque enfant suggère que l'antalgie administrée en cours de traitement est suffisante. Utiliser ce capteur de manière prolongée et sur un grand collectif d'enfants serait un moyen fiable et simple d'objectiver la dynamique de reprise de l'activité physique chez ces patients. Profil de l'étude : observation de cas.

Na 50 Nachlass Arthur Schopenhauer - 'Schopenhauer-Archiv', 768 - Benachrichtigung über Verspätung in Frankfurt wegen eines Unfalls mit der Kutsche

u.a. Organisation der Reise; Finanzen; Daguerreotypie;

Ms. Ff. Mus. 768 - Feria II. Pentec.

Telemann. [Text: Gottfried Simonis]

Electrical properties of basalts of ODP Sites 124-768 and 124-770

Conductivity of 54 basalt samples from ODP Sites 768 and 770 was measured as a function of temperature and fluid salinity. Porosity was also measured for all samples, and cation exchange capacity was measured for 46 of the samples. Porosity measurements indicated that porosity is underestimated for basalts like these, unless one uses extensive drying at high vacuum. At salinities greater than 29 ppt, and throughout the range of salinity and temperatures likely in situ, sample conductivity (Co) is controlled by porosity (phi) according to the Archie relation Co = 0.22*Cw phi*1-3 (orFF = 4.5/f1.3), where Cw is conductivity of the pore fluids and FF = Cw/CO is the formation factor. At lower salinity, clay-surface conduction or microcrack conduction may dominate. We are unable to distinguish reliably between the two mechanisms, but we do detect their effects subtly at high salinity and strongly at low salinity.

Organic sedimentation of ODP Sites 124-767 and 124-768

This study relates the organic sedimentation characteristics to the lithostratigraphic successionsthat were observed at Site 767 (Celebes Sea) and Site 768 (Sulu Sea) during ODP Leg 124. It is based on the total organic carbon content (TOC) of the sediments, on the petrographictype and maturity of the organic matter, and on the TOC accumulation rates calculated for the lithostratigraphic units. In the Celebes and Sulu Seas sediments, the organic matter is mainly of terrestrial origin with the highest concentrations and TOC accumulation rates occurring in the middle Miocene turbiditic sequences that correspond to a major compressive event between the Philippine Mobile Belt and the Palawan, Cagayan, and Sulu Ridges. Petrographic analysis of the Eocene and lower Miocene organic matter in the Celebes Sea shows that it consists only of highly degraded terrestrial particles. This observation and the very low TOC accumulation rates indicate poor conditions for organic carbon preservation during this open-ocean phase of the Celebes Basin formation. The organic matter, either of marine or terrestrial origin, is much better preserved in the younger sediments, suggesting physico-chemical changes in the depositional environment. Because of the dilution phenomena by turbidites, it is difficult to observe the progressive improvement of the organic matter preservation throughout the turbiditic series. The same change in preservation is broadly observed in the Sulu Sea from the early Miocene (rapid opening phase of the basin with massive pyroclastic deposits) to the present.

Pore-water chemistry of ODP Sites 124-767 and 124-768

The combination of multiple sediment sources and varying rates of sediment accumulation in the Celebes and Sulu seas have had significant impact on the processes of diagenesis, mineralization, and pore-fluid flow. Isotopic and mass-balance calculations help elucidate the various reactions taking place in these western Pacific basins, where ash alteration and basalt-seawater interactions are superimposed on the effects of sulfate oxidation of organic carbon and biogenic methane and of dolomitization of biogenic carbonates. Based on the shape of the calcium and magnesium depth profiles, two major reactive zones have been identified. The first is located near the zone of sulfate depletion and is characterized by carbonate recrystallization, dolomitization and ash alteration reactions at both Ocean Drilling Program Sites 767 and 768. The second reactive zone corresponds to the bottom of the sedimentary sequence and is characterized by alteration reactions in the basement (Site 767) and in the pyroclastic deposits beneath the sediment column (Site 768).

Occurrence and type of dolomite in ODP Site 124-768 samples (Table 1)

Occurrence of deep-sea dolomites has been reported from numerous settings (for discussion see Lumsden, 1988). Different authors agree that dolomite formation in the pelagic realm is a relatively early diagenetic process (e.g., Jorgensen, 1983; Shimmield and Price, 1984; Kablanow et al., 1984; Kulm et al., 1984). Baker and Burns (1985) suggest that most of the pelagic dolomites formed within a few tens of meters below the seafloor within the zone of microbial sulfate reduction. According to Fuechtbauer and Richter (1988), dolomite can form in the deep-sea at a minimum temperature of 10°C. Other deep-sea dolomites are products of fluids derived from underlying evaporites or submarine weathering of basalts (Garrison, 1981). In some cases (Mullins et al., 1985; Dix and Mullins, 1988; Mullins et al., 1988), the existence of dolomite is linked to disconformities and its formation may have resulted from circulation of seawater through the sediment during prolonged exposure (Dix and Mullins, 1988, p. 287). At Site 768 (Fig. 1), lithified carbonate layers, some containing variable amounts of dolomite, occur below 201 mbsf (Miocene). These beds alternate with unconsolidated or semi-lithified marl layers interbedded in clays and siliciclastic turbidites. The irregular depth distribution of the limestone beds and the variation in preservation and recrystallization of the calcareous microfaunas suggest that lithification of carbonates at Site 768 not only reflects burial diagenesis as described by Garrison (1981) and others, but in part may be a selective, early diagenetic process. The different types and distribution of the dolomite additionally seem to support this assumption. The purpose of this report is to document the occurrence and textural nature of the dolomite at Site 768. Methods used were analyses of stained thin sections (Alizarin S and Ferrocyanide) and studies with the scanning electron microscope. No geochemical analyses (e.g., stable isotopes) were carried out; they will be the subject of further investigations.

Light hydrocarbons in sediments of ODP Site 124-768

Geochemical investigations on gases and interstitial waters from ODP Site 768 (Sulu Trench/Philippines) demonstrate the application of molecular gas composition in combination with stable isotope analyses to the genetic classification of light hydrocarbons. 13C/12C and D/H ratios of methane from gas pockets in cores and gases desorbed from frozen sediments by a vacuum/acid treatment suggest a microbial generation of methane by a CO2 reducing process in sediments with low sulfate concentrations. Isotope data and molecular composition of sediment gases liberated by the vacuum/acid treatment seem to be affected by a secondary desorption process during sampling. A comparison between the D/H ratios of methane from gas pockets and interstitial H2O points to an in-situ generation of methane down to a sub-bottom depth of approx. 720 m. Below this depth hydrogen isotope data indicate a migration of light hydrocarbons into pyroclastic sediments at this site. The occurrence of higher hydrocarbons (propane to pentane) in gases from gas pockets coincides with the vertical distribution of mature organic matter. Gases within the zone of mature organic matter are gases of a mixed microbial and thermal origin.