This work provides detailed information of outcrop gamma-ray logging from the Sinemurian-Pliensbachian organic-rich units (Água de Madeiros and Vale das Fontes formations) of the Lusitanian Basin, which are recognized as one of the most important potential oil source rocks interval of Portugal. The study included total and spectral gamma-ray measurements in outcrop and laboratory, Total Organic Carbon (TOC) content and whole-rock mineralogical characterization by X-ray diffraction, carried out in the two most important outcrop areas of the Western Lusitanian Basin (S. Pedro de Moel and Peniche). The outcrop data was compared with subsurface information.The results show high variability of the gamma radiation (26 to 210 cps) and radioactive elements associated with the lithological, mineralogical and geochemical differences. The TOC data yielded the organic matter enrichment of both formations, where the highest values are observed in the Água de Madeiros Formation (maximum=20.4%). The highest U concentration (11 ppm) is consistent with the highest Total Organic Carbon peak mainly supported by the precipitation of authigenic U (10 ppm). The majority of the analysed samples show an obvious authigenic U enrichment, especially in the Água de Madeiros Formation where it represents the main component of the total U content. A highly significant U/TOC correlation (r up to 0.87) with a low ratio (0.3-0.7 ppm/wt.%TOC) was obtained, confirming that U content can be used as a proxy for organic richness in the studied depositional system. The gamma-ray tool was also useful in the identification of 2 nd order Transgressive-Regressive facies cycles (and maximum flooding surfaces) and in the correlation between outcrop and subsurface data.

No abstract

Patient positioning on the surgical table is a critical step in every spine surgery. The most common surgical positions in spine surgery are supine, prone and lateral decubitus. There are countless lesions that can occur during spine surgery due to patient mispositioning. Ulnar nerve and brachial plexus injuries are the most common nerve lesions seen in malpositioned patients. Devastating complications due to increased intraocular pressure or excessive abdominal pressure can also occur in prone decubitus and are real concerns that the surgical team must be aware of. All members of the surgical team (including surgeons, anesthesiologists and nurses) should know how to correctly position the patient, identify possible positioning errors and know how to avoid them in order to prevent postoperative morbidity. This work pretends to do a review of the most common positions during spine surgery, alert to errors that can happen during the procedure and how to avoid them.

No abstract