Erupciones Volcánicas de la Cuenca de México y sus effectos en poblaciones humanas tempranas del Pleistoceno Superior-Holoceno Temprano.

La Cuenca de México esta situada a una altura de 2,500 metros y se localiza dentro del Eje Volcánico Transmexicano. Todas las montañas que rodean a la Cuenca son de origen volcánico. En particular 3 erupciones volcánicas importantes de tipo Pliniano produjeron depósitos volcánicos asociados con cenizas volcánicas “marcadoras” en la Cuenca producidas durante la transición del Pleistoceno Superior – Holoceno Temprano. Estas son: 1) Gran Ceniza Basáltica, producida por la Sierra de Santa Catarina, con una edad de 28,600 años; 2) Pómez con Andesita producida por el Volcán Popocatépetl hace14,600 años 3) Pómez Toluca Superior (Tripatita) producida por el Volcán Nevado de Toluca, hace 10,500 años. Durante este intervalo de tiempo se tienen fechados varios sitios Paleoindios con la presencia tanto de esqueletos humanos embebidos en ceniza volcánica asociada con la Pómez Toluca Superior (Hombre del Metro Balderas), asi como sitios con megafauna asociada con lahares (flujos de lodo volcánico) en el sitio de Mamuts de Tocuila. Las erupciones volcánicas tuvieron un impacto muy importante tanto en el medio ambiente de la Cuenca asi como en las poblaciones humanas Paleoindias y la megafauna asociada (mamuts, camellos, caballos, gliptodontes) durante la transición del Pleistoceno-Holoceno Temprano

Erupciones Volcánicas de la Cuenca de México y sus effectos en poblaciones humanas tempranas del Pleistoceno Superior-Holoceno Temprano.

La Cuenca de Mexico esta situada a una altura de 2,500 metros y se localiza dentro del Eje Volcánico Transmexicano. Todas las montañas que rodean la Cuenca son de origen volcánico. En particular 3 erupciones volcánicas de tipo Pliniano produjeron depósitos volcanicos asociados con cenizas volcánicas marcadoras en la Cuenca producidas durante la transición del Pleistoceno-Holoceno Superior. Estas son: 1) Gran Ceniza Basáltica, producida por la Sierra de Santa Catarina, con una edad de 28,600 años; 2) Pómez con Andesita producida por el Volcán Popocatépetl hace14,600 años y 3) Pómez Toluca Superior (Tripatita) producida por el Volcán Nevado de Toluca, hace 10,500 años. Durante este intervalo de tiempo se tienen fechados, varios sitios Paleoindios con la presencia tanto de esqueletos humanos embebidos en ceniza volcánica asociada con la Pomez Toluca Superior (Hombre del Metro Balderas), asi como sitios con megafauna asociada con lahares (flujos de lodo volcánico) en los sitios de Mamutes de Tocuila. Las erupciones volcanicas han tenido un impacto muy importante tanto en el medio ambiente de la Cuenca asi como en las poblaciones humanas Paleoindias y la megafauna asociada (mamutes, camellos, gliptodontes) durante la transición del Pleistoceno-Holoceno Superior

Cost-effectiveness of a quality improvement bundle for emergency laparotomy.

Background: The recent Emergency Laparotomy Pathway Quality Improvement Care (ELPQuiC) study showed that the use of a specific care bundle reduced mortality in patients undergoing emergency laparotomy. However, the costs of implementation of the ELPQuiC bundle remain unknown. The aim of this study was to assess the in-hospital and societal costs of implementing the ELPQuiC bundle. Methods: The ELPQuiC study employed a before-after approach using quality improvement methodology. To assess the costs and cost-effectiveness of the bundle, two models were constructed: a short-term model to assess in-hospital costs and a long-term model (societal decision tree) to evaluate the patient's lifetime costs (in euros). Results: Using health economic modelling and data collected from the ELPQuiC study, estimated costs for initial implementation of the ELPQuiC bundle were €30 026·11 (range 1794·64-40 784·06) per hospital. In-hospital costs per patient were estimated at €14 817·24 for standard (non-care bundle) treatment versus €15 971·24 for the ELPQuiC bundle treatment. Taking a societal perspective, lifetime costs of the patient in the standard group were €23 058·87, compared with €19 102·37 for patients receiving the ELPQuiC bundle. The increased life expectancy of 4 months for patients treated with the ELPQuiC bundle was associated with cost savings of €11 410·38 per quality-adjusted life-year saved. Conclusion: Implementation of the ELPQuiC bundle is associated with lower mortality and higher in-hospital costs but reduced societal costs

Second cancer risk and mortality in men treated with radiotherapy for stage I seminoma

BACKGROUND: Patients with stage I testicular seminoma are typically diagnosed at a young age and treatment is associated with low relapse and mortality rates. The long-term risks of adjuvant radiotherapy in this patient group are therefore particularly relevant. METHODS: We identified patients and obtained treatment details from 12 cancer centres (11 United Kingdom, 1 Norway) and ascertained second cancers and mortality through national registries. Data from 2629 seminoma patients treated with radiotherapy between 1960 and 1992 were available, contributing 51,151 person-years of follow-up. RESULTS: Four hundred and sixty-eight second cancers (excluding non-melanoma skin cancers) were identified. The standardised incidence ratio (SIR) was 1.61 (95% confidence interval (CI): 1.47-1.76, P<0.0001). The SIR was 1.53 (95% CI: 1.39-1.68, P<0.0001) when the 32 second testicular cancers were also excluded. This increase was largely due to an excess risk to organs in the radiation field; for pelvic-abdominal sites the SIR was 1.62 (95% CI: 1.43-1.83), with no significant elevated risk of cancers in organs elsewhere. There was no overall increase in mortality with a standardised mortality ratio (SMR) of 1.06 (95% CI: 0.98-1.14), despite an increase in the cancer-specific mortality (excluding testicular cancer deaths) SMR of 1.46 (95% CI: 1.30-1.65, P<0.0001). CONCLUSION: The prognosis of stage I seminoma is excellent and it is important to avoid conferring long-term increased risk of iatrogenic disease such as radiation-associated second cancers

Five Younger Dryas black mats in Mexico and their stratigraphic and paleoenvironmental context

The Younger Dryas interval (YD) was a period of widespread, abrupt climate change that occurred between 12,900 and 11,700 cal yr BP (10,900–10,000 14 C BP). Many sites in the Northern Hemisphere preserve a sedimentary record across the onset of the YD interval, including sites investigated in sedimentary basins located in central Mexico (Chapala, Cuitzeo, Acambay), the Basin of Mexico (Tocuila), and northern Mexico (El Cedral). Deposits consist of lacustrine or marginal lake sediments that were deposited during the Pleistocene and the Holocene. At the Tocuila and Acambay sites, Pleistocene fossil vertebrate assemblages, mainly mammoths (Mammuthus columbi), are found in association with a distinctive organic layer, sometimes called the black mat that formed during the YD. At the Chapala, Cuitzeo, Acambay, and Tocuila sites the black mats contain a suite of distinctive microscopic and mineralogical signatures and are accompanied by a sharp change in the depositional environments as supported by diatom and pollen studies reported here. The signatures include magnetic, Fe-rich microspherules, silica melted droplets with aerodynamic shapes (tektites), large amounts of charcoal, and sometimes nanodiamonds (Cuitzeo), all of which were deposited at the onset of the YD. The geochemistry of the microspherules indicates that they are not anthropogenic, authigenic or of cosmic or volcanic origin, and instead, were produced by melting and quenching of terrestrial sediments. Here, we present the stratigraphy at five field sites, the analyses of magnetic microspherules, including major element composition and scanning electron microscopy images. All of these materials are associated with charcoal and soot, which are distinctive stratigraphic markers for the YD layer at several sites in Mexico. © 2017 Springer Science+Business Media B.V

Fluorodeoxyglucose positron emission tomography in the evaluation of germ cell tumours at relapse

Differentiation of active disease from fibrosis/mature teratoma in patients with residual masses or identifying of sites of recurrence in patients with raised markers following treatment of their testicular cancer remains a problem.18F-fluorodeoxyglucose positron emission tomography (FDG-PET) has the potential to identify active disease and thereby influence further management in these patients. We performed a retrospective study of the use of FDG-PET in detecting residual/recurrent testicular carcinoma in 55 patients (seventy FDG-PET scans). Forty-seven scans were for the assessment of residual masses (18 had raised markers) and 23 scans were for the investigation of raised markers in the presence of normal CT scans. True positive results were based on positive histology or clinical follow-up. FDG-PET had a positive predictive value (PPV) of 96% and a negative predictive value (NPV) of 90% in patients with residual masses. This PPV was equivalent to that of markers (94%) but FDG-PET had the advantage of identifying the site of that recurrence. The NPV was higher than that of markers. In patients with raised markers alone the PPV of FDG-PET was 92% but the NPV was only 50%. However, subsequent FDG-PET imaging was frequently the first imaging modality to identify the site of disease. FDG-PET effected a management change in 57% of cases. FDG-PET scanning detected viable tumour in residual masses and identified sites of disease in suspected recurrence. © 2000 Cancer Research Campaig