Finding of the first fossil seep in the emerged coast of Central Chile (33°56’ S). Characterization and implications

Indexación: Scopus.This study presents the main characteristics of the first fossil hydrocarbon seep documented on the emerged coast of Central Chile. The Navidad Paleoseep (NPS) is an outcrop of carbonate and fossil organisms preserved on the beach of the Navidad locality. The carbonate structure is oriented N45° W, perpendicular to the coastline and discordant with sub horizontal Miocene sequences found in the area. This type of authigenic carbonate accumulation, originates on the sea floor as the result of anaerobic oxidation of methane, generated by low temperature fluids released through seafloor fractures. The NPS consists mainly of calcium carbonate in the form of matrix and crystallized precipitate. Based on textural features, dominant facies of the outcrop were defined as mudstone and wackestone. The associated mineralogy consists of magnesian calcite, predominantly as micrite matrix, minor components of quartz, albite, amphibole, orthoclase, microcline and fragments of volcanic lithics are also identified. The NPS also contains a variety of fossils, such as bivalves, gastropods, tube worms, teredolites, microbialites and others. The occurrence of Lucinoma promaucana in the paleoseep, evidences a temporal and spatial correlation with the Navidad Formation i.e., would ranges from lower to middle Miocene. The δ13C values vary between -41.4‰ in the matrix and -29.5‰ PDB in bivalve shells, representing the typical negative δ13C values seen in hydrocarbon seeps.http://www.andeangeology.cl/index.php/revista1/article/view/V44n2-a0

Prophylactic Cefazolin Dosing and Surgical Site Infections: Does the Dose Matter in Obese Patients?

Background Most surgical prophylaxis guidelines recommend a 3-g cefazolin intravenous dose in patients weighing ≥ 120 kg. However, this recommendation is primarily based on pharmacokinetic studies rather than robust clinical evidence. This study aimed to compare the prevalence of surgical site infections (SSIs) in obese and non-obese patients (body mass index ≥ 30 kg/m2 and < 30 kg/m2), and those weighing ≥ 120 kg and < 120 kg, who received 2- g cefazolin preoperatively. Methods A retrospective case-control study was conducted in adult elective surgical patients. Patients receiving 2- g cefazolin were grouped as obese and non-obese, and by weight (≥ 120 kg or < 120 kg). The 90-day prevalence of SSI and potential contributing factors were investigated. Results We identified 152 obese (median 134 kg) and 152 non-obese control (median 73 kg) patients. Baseline characteristics were similar between groups, except for an increased prevalence in the obese group of diabetes (35.5% vs 13.2%; p < 0.001) and an American Society of Anaesthesiologists Score of 3 (61.8% vs 17.1%; p < 0.001). While not statistically significant, the prevalence of SSI in the obese group was almost double that in the non-obese group (8.6% vs 4.6%; p = 0.25) and in patients weighing ≥ 120 kg (n = 102) compared to those weighing < 120 kg (n = 202) (9.8% vs 5.0%; p = 0.17). Conclusion The prevalence of SSI was not significantly increased in obese patients, or those weighing ≥ 120 kg, who received cefazolin 2- g prophylactically; however, trends toward an increase were evident. Large-scale randomised trials are needed to examine whether a 2-g or 3-g cefazolin is adequate to prevent SSI in obese (and ≥ 120 kg) individuals