Geochemical indications for the Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM-2) hyperthermals in terrestrial sediments of the Canadian Arctic

During the late Paleocene to early Eocene, clastic fluvial sediments and coals were deposited in northern high latitudes as part of the Marga­ret Formation at Stenkul Fiord (Ellesmere Island, Nunavut, Canada). Syn-sedimentary tectonic movements of the Eurekan deformation continu­ously affected these terrestrial sediments. Different volcanic ash layers occur, and unconformities subdivide the deposits into four sedimentary units. Rare vertebrate fossils indicate an early Eocene (Graybullian) age for the upper part of the Stenkul Fiord outcrop. Here, we present carbon isotope data of bulk coal, related organic-rich mud and siltstones, a plant leaf wax-derived alkane, and additional plant remains. These data provide a complete carbon isotope record of one stratigraphic section with defined unconformity positions and in relation to other Eurekan deformation features. A previously dated ash layer MA-1 provided a U-Pb zircon age of 53.7 Ma and is used as a stratigraphic tie point, together with a discrete negative carbon isotope excursion found above MA-1 in a closely sampled coal seam. The excursion is identified as the likely expression of the I-1 hyperthermal event. Based on our isotope data that reflect the early Eocene dynamics of the carbon cycle, this tie point, and previous paleontological constraints from vertebrate fossils, the locations of the Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM-2) hyperthermals and their extent along the complete section are herein identified. Within the intervals of the PETM and ETM-2 hyperthermal events, increasing amounts of clastic sediments reached the site toward the respective end of the event. This is interpreted as a response of the fluvial depositional system to an intensified hydrological system during the hyperthermal events. Our study establishes an enhanced stratigraphic framework allowing for the calcula­tion of average sedimentation rates of different intervals and considerations on the completeness of the stratigraphic record. As one of the few high-latitude outcrops of early Eocene terrestrial sediments, the Stenkul Fiord location offers further possibilities to study the effects of extreme warming events in the Paleogene.

Blunt abdominal trauma with duodenal dissection: A case report

We describe a new case of duodenal wound with complete transection in a 22-year-old patient following a motorcycle accident. He presented to the emergency room of the rural Regional Hospital of Edéa in Cameroon with a clinical picture of acute abdomen and post-trauma hemodynamic instability. A peritoneal puncture brought back an incoagulable blood. An exploratory laparotomy revealed a large hemoperitoneum mixed with food debris. A tear of the omentum and transverse mesocolon and a complete section of the third duodenum at the beginning of its free portion were observed. The surgeon performed emergency closure of both duodenal stumps and performed an isoperistaltic lateral gastrojejunal bypass. A transfer to a specialized center for a more anatomical continuity was considered, but the imminence of a humanitarian mission in the hospital prompted the surgeon to seize the opportunity of this mission for the reoperation. This surgical revision was performed on the fifth postoperative day. A resection of the distal duodenal stump and the adjacent jejunal segment including the anastomosis was performed. Continuity was restored by a mechanical duodenal-jejunal anastomosis. The patient was discharged on the 18th postoperative day. This type of lesion is difficult to manage in an emergency situation in a structure with limited technical resources. Unfortunately, surgeons treating polytraumatized civilians are encountering an increasing number of blunt duodenal wounds requiring laborious management.

Complete section of the left vagus nerve does not preclude the efficacy of vagus nerve stimulation: illustrative case

BACKGROUND Vagus nerve stimulation (VNS) represents a valid therapeutic option for patients with medically intractable seizures who are not candidates for epilepsy surgery. Even when complete section of the nerve occurs, stimulation applied cranially to the involved nerve segment does not preclude the efficacy of VNS. Complete vagus nerve section with neuroma causing definitive left vocal cord palsy has never been previously reported in the literature. OBSERVATIONS Eight years after VNS implant, the patient experienced worsening of seizures; the interrogation of the generator revealed high impedance requiring surgical revision. On surgical exploration, complete left vagus nerve section and a neuroma were found. Vocal cord atrophy was found at immediate postoperative laryngeal inspection as a confirmation of a longstanding lesion. Both of these events might have been caused by direct nerve injury during VNS surgery, and they presented in a delayed fashion. LESSONS VNS surgery may be complicated by direct damage to the left vagus nerve, resulting in permanent neurological deficits. A complete section of the nerve also enables an efficacious stimulation if applied cranially to the involved segment. Laryngeal examination should be routinely performed before each VNS surgery to rule out preexisting vocal cord dysfunction.

New high precision U-Pb CA-ID-TIMS zircon ages from the Ediacaran in Namibia

<p>The Ediacaran records a transition from a planet largely dominated by microscopic organisms to macroscopic multicellular organisms during the Phanerozoic. Temporal calibration of the record of changing climates and coevally diversifying biota is crucial to understand how metazoan life gained an early foothold on Earth.</p><p>A causal link between climate-driven environmental perturbations and biotic changes is generally accepted. However, a chronological relationship is needed to prove which event acted as a trigger for the biological turnover, i.e. extinction or the development of new organizational levels. A connection between environmental perturbations associated with the appearance and disappearance of the Ediacaran biota is profoundly complicated because of the scarcity of available geochronological and chemostratigraphical records. Therefore, it is crucial to expand existing datasets for this period, particularly through additional chronology.</p><p>The Nama Group in southern Namibia serves as a unique archive for major geobiological changes across the Ediacaran–Cambrian transition exemplified by a near complete section through the terminal Ediacaran. The region exposes the full stratigraphic range of the Nama assemblage and records several environmental perturbations. Establishing a precise timeframe of the terminal Ediacaran environmental and biological changes in Nama group enables a much-enhanced understanding of the nature and rates of the evolutionary changes.</p><p>Following pioneering research by Grotzinger et al. (1995), the Ediacaran–Cambrian boundary in Namibia has recently been dated ca. 2 Ma younger than previously assumed [1]. Additional high-precision U-Pb CA-ID-TIMS zircon ages from silicified tuffs of the Nama Group allow additional insights for the timeframe of the entire terminal Nama. Our results indicate that (i) the oldest ash bed in the Zaris subbasin is 547.3 Ma old, which makes it more than 0.5 Ma younger than the previously dated tuff in the same subbasin; (ii) a newly explored section at the base of the terminal Ediacaran Spitskop Member near the MTC tower (Witpütz Nord farm) revealed a slightly younger age of 539 Ma, which permits a precise correlation of this section with the Swartpunt section and indicates the position of the Ediacaran-Cambrian boundary.</p><p>[1] Linnemann, U. et al., (2019) Terra Nova 31(1) 49-58.</p>

ON STANDARDIZATION OF LABORATORY SOIL TESTING IN OFFSHORE GEOTECHNICAL SURVEY

Issues of laboratory soil studies standardization in offshore geotechnical survey are discussed in connection with the end of expertise of two new regulative documents – new edition of the Code of practice and Russian national standard developed on the basis of international ISO standard. Since these documents of different level belong also to different categories (geotechnical survey and oil and gas industry), the authors analyze their interrelation and consistency, from one hand, and the preparedness of Russian soil testing practice to implementation of the new standard which results from harmonization with international ones, from the other. Complete section of the standard draft related to soil laboratory testing is presented, preceded by commentary on some important issues regarding the implementation of its specific methodic statements. It is concluded that the new national GOST draft «Petroleum and natural gas industries. Specific requirements for offshore structures. Marine soil investigations» developed on ISO basis will be a useful document supported in general by Russian normative base but expanding a possible range of voluntary methods into well time-tested foreign approaches. This documents can be considered to be a toolkit annex to the Code of practice describing testing approaches beyond the scope of typical tasks

Functional anatomy of the sagittal bands and mechanisms of extensor tendon dislocation: a cadaveric study

We investigated the functional anatomy of the radial sagittal band and possible mechanisms involved in its spontaneous and traumatic rupture using seven cadaveric hands. First, the extensor tendon excursion and the change in angle between the sagittal bands and the tendon path were measured during metacarpophalangeal joint flexion. The radial bands were then divided in two different ways that mimicked spontaneous or traumatic rupture. We found no significant correlation between the extensor tendon excursion and the change in angle of the sagittal bands in the middle and ring fingers. Dislocation could occur when the radial sagittal band was only partially divided. This may explain why conservative treatment of tendon dislocation in the middle and ring fingers is feasible. Complete section of the sagittal bands in the little finger caused ulnar dislocation of the extensor tendon in only one out of seven hands.

Anatomical Study of Minimally Invasive Lateral Release Techniques for Hallux Valgus Treatment

Background: Lateral release (LR) for the treatment of hallux valgus is a routinely performed technique, either by means of open or minimally invasive (MI) surgery. Despite this, there is no available evidence of the efficacy and safety of MI lateral release. Our aim was to study 2 popular techniques for MI LR in cadavers by subsequently dissecting the released anatomical structures. Methods: Twenty-two cadaveric feet were included in the study and allocated into 2 groups, 1 for each procedure: 1 group underwent a MI adductor tendon release (AR), and in the other group, an extensive percutaneous lateral release (EPLR) (adductor tendon, suspensory ligament, phalanx-sesamoid ligament, lateral head of flexor hallucis brevis, and deep transverse metatarsal ligament) was performed. Anatomical dissection was performed to identify neurovascular injuries and to verify the released structures. Results: Both techniques demonstrated to be effective in reproducing a MI LR. A satisfactory release of the adductor tendon was achieved equally in both techniques ( P = .85), being partial in most EPLR cases and full in the majority of AR cases. The EPLR was successful in releasing the intended additional structures ( P < .05). One case of inadvertent complete section of the flexor hallucis longus was identified in the percutaneous adductor tendon release group. No cases of dorsolateral nerve injury were seen with either of the techniques. Conclusion: Percutaneous lateral release was a reliable and accurate technique in this cadaveric model. The MI AR proved to be more effective in fully releasing the adductor tendon while the ER was intended and able to release a number of other structures. Clinical Relevance: MI LR is a safe procedure that could obviate the need for open surgery to achieve the same surgical goal. It can be associated to either open or MI osteotomies in the correction of hallux valgus.

Detailed descriptions of the lower-middle Triassic and Permian formations using cores and gamma-rays from the EPS-1 exploration geothermal borehole (Soultz-sous-Forêts, Upper Rhine Graben, France)

In the 1950s, a petroleum well in Soultz-sous-Forêts (no 4589; Upper Rhine Graben, France) reached the Lettenkohle (Triassic) at 830 m depth. During the exploration phase at Soultz-sous-Forêts, the first enhanced geothermal system pilot project in the world, the well was core-deepened up to 2227 m into the granitic basement (then renamed EPS-1). The objectives of this deeper well were (i) to explore the granitic fractured reservoir and (ii) provide a precise geological characterization of the Soultz-sous-Forêts horst. This paper presents the first complete core analysis of the sedimentary formations observed in the EPS-1 cores (from the middle Muschelkalk to the Permian) in conjunction with the gamma-ray log description and field works. The detailed descriptions of the geological formations encountered in the well are presented with photo boards displaying the most characteristic facies of each formation, since the wells are rarely cored, especially in the Muschelkalk. This study also aims to describe the gamma-ray log to provide a strong baseline for future geothermal well exploration in this area (or old well reinterpretations). At this time, it is the only available reference for the complete section: Muschelkalk to Permian sedimentary formations.

Palmar Arch: Anatomical And Surgical Correlation in Trauma

The irrigation of the palm is provided by arterial arches (shallow and deep) that are made more frequently by the ulnar or radial arteries described as setting a classic pattern. Anatomical variations are described in shaping both arches, most often in the superficial palmar arch; may be the same complete or incomplete. The objective of this work is the anatomical description of the palmar arches, their different patterns and variations in conformation, and their clinical and surgical implications. A descriptive, observational and morphometric study of the arteries involved in the formation of the palmar arches was done in the Faculty of Medicine, University of Buenos Aires. One hundred1(00) cadaveric preparations fixed in formalin solution, of the Third Chair of Anatomy were used. A retrospective analysis of cases with lesions / s artery / main / s that make the palmar arches in the Emergency Hospital of Moron, between 2015-2016 s was also carried out. Most frequently the radial artery forms the deep palmar arch with the deep palmar branch of the ulnar artery. Superficial palmar arch is the most variable. It was complete in 56 % and the most common presentation (83 %) is one that is formed by the anastomosis of the ulnar artery and the superficial palmar branch of the radial artery. The rest of the anastomosis are between ulnar artery and median artery (9%), between deep branch of radial artery and ulnar artery (5 %); triple anastomosis between ulnar artery, median artery and superficial palmar branch of the radial artery (2 %), and anastomosis between the median artery and superficial palmar branch of the radial artery without participation of the ulnar artery (1 %). The rest of the sample (44 %) can be termed as incomplete. The B1a and B1b subtypes were the most found. Two cases, one entire section of the radial artery at the wrist and the other with complete section of ulnar artery with involvement of the ulnar nerve are described. It is essential to a proper understanding of the palmar arches for a suitable surgical approach to hand. The importance of the presence or absence, as well as different variations of palmar arterial arch lies in its clinical application as surgical starting point in the treatment of trauma and other diseases in which there is engagement of arteries.