24 research outputs found

    First directional European palaeosecular variation curve for the Neolithic based on archaeomagnetic data

    Get PDF
    Neolithic, Chalcolithic and Bronze Age anthropogenic cave sediments from three caves from northern Spain have been palaeomagnetically investigated. 662 oriented specimens corresponding to 39 burning events (ash–carbonaceous couplets) from the three sites with an average of 16 samples per fire were collected. 26 new archaeomagnetic directions have been obtained for the time period ranging from 5500 to 2000 yr cal. BC. These results represent the oldest archaeomagnetic directions obtained from burnt archaeological materials throughout all Western Europe. Magnetisation is carried by pseudo-single domain low-coercivity ferromagnetic minerals (magnetite, magnetite with no significant isomorphous substitution and/or maghaemite). Rock-magnetic experiments indicate a thermoremanent origin of the magnetisation although a thermochemical magnetisation cannot be excluded. Combination of the new data presented here and the recent updated Bulgarian database allows us to propose the first European palaeosecular variation (PSV) curve for the Neolithic. A bootstrap method was applied for the curve construction using penalised cubic B-splines in time. The new palaeosecular variation curve is well constrained from 6000 BC to 3700 BC, the period with the highest density of data, showing a declination maximum around 4700 BC and a minimum in inclination at 4300 BC, which are not recorded by the recent global CALS10K.1b and regional SCHA.DIF.8K models due to the use of lake sediment data. Dating resolution by using the proposed PSV curve oscillates from approximately ±30 yr to ±200 yr for the period 6000 to 1000 yr BC, reaching similar resolution as radiocarbon dating. Considering the good preservation, age-control and widespread occurrence of burnt archaeological materials across Southern Europe, they represent a new source of data for geomagnetic field modelling, as well as for archaeomagnetic dating.Published124-1371A. Geomagnetismo e PaleomagnetismoJCR Journalrestricte

    Initial SCHA.DI.00 regional archaeomagnetic model for Europe for the last 2000 years

    No full text
    International audienceThe available Bayesian European Palaeosecular Variation Curves (PSVC) based on archaeomagnetic data have been used to derive an initial regional model for the geomagnetic field in Europe for the last 2000 years by using the Spherical Cap Harmonic Analysis (SCHA) technique. The resulting SCHA.DI.00 model provides the directional behaviour of the Earth's magnetic field, but no information about intensity is supplied because input data are only directional. The first spherical cap harmonic coefficient, , has been used to normalise the rest of the coefficients. The spherical expansion extends up to Kint = 2 which, given the size of the spherical cap used and the maximum data resolution, is equivalent, in terms of spatial wavelength, to a maximum degree of approximately 5 in the ordinary Spherical Harmonic Analysis (SHA). The SCHA.DI.00 model fits the present archaeomagnetic database for Europe more accurately than global models, although it is necessary to consider that regional SCHA model and global models did not use the same database. Palaeosecular variation curves given by SCHA.DI.00 are compared with available archaeomagnetic data from Bulgaria (Sofia), Italy (Etna) and Austria (Radstadt), not used in the development of the model. The SCHA.DI.00 model improves the fit to these palaeomagnetic data with respect to the CALS7K.2 [Korte, M., Constable, C.G., 2005. Continuous geomagnetic field models for the past 7 millennia: 2. CALS7K. Geochem. Geophys. Geosyst. 6, Q02H16. doi:10.1029/2004GC000801] global model, especially for Italy

    2700 years of Mediterranean environmental change in central Italy: a synthesis of sedimentary and cultural records to interpret past impacts of climate on society

    No full text
    Abrupt climate change in the past is thought to have disrupted societies by accelerating environmental degradation, potentially leading to cultural collapse. Linking climate change directly to societal disruption is challenging because socioeconomic factors also play a large role, with climate being secondary or sometimes inconsequential. Combining paleolimnologic, historical, and archaeological methods provides for a more secure basis for interpreting the past impacts of climate on society. We present pollen, nonpollen palynomorph, geochemical, paleomagnetic and sedimentary data from a high-resolution 2700 yr lake sediment core from central Italy and compare these data with local historical documents and archeological surveys to reconstruct a record of environmental change in relation to socioeconomic history and climatic fluctuations. Here we document cases in which environmental change is strongly linked to changes in local land management practices in the absence of clear climatic change, as well as examples when climate change appears to have been a strong catalyst that resulted in significant environmental change that impacted local communities. During the Imperial Roman period, despite a long period of stable, mild climate, and a large urban population in nearby Rome, our site shows only limited evidence for environmental degradation. Warm and mild climate during the Medieval Warm period, on the other hand, led to widespread deforestation and erosion. The ability of the Romans to utilize imported resources through an extensive trade network may have allowed for preservation of the environment near the Roman capital, whereas during medieval time, the need to rely on local resources led to environmental degradation. Cool wet climate during the Little Ice Age led to a breakdown in local land use practices, widespread land abandonment and rapid reforestation. Our results present a highresolution regional case study that explores the effect of climate change on society for an underdocumented region of Europe

    Patients with Crohn's disease have longer post-operative in-hospital stay than patients with colon cancer but no difference in complications' rate

    Get PDF
    BACKGROUNDRight hemicolectomy or ileocecal resection are used to treat benign conditions like Crohn's disease (CD) and malignant ones like colon cancer (CC).AIMTo investigate differences in pre- and peri-operative factors and their impact on post-operative outcome in patients with CC and CD.METHODSThis is a sub-group analysis of the European Society of Coloproctology's prospective, multi-centre snapshot audit. Adult patients with CC and CD undergoing right hemicolectomy or ileocecal resection were included. Primary outcome measure was 30-d post-operative complications. Secondary outcome measures were post-operative length of stay (LOS) at and readmission.RESULTSThree hundred and seventy-five patients with CD and 2,515 patients with CC were included. Patients with CD were younger (median = 37 years for CD and 71 years for CC (P < 0.01), had lower American Society of Anesthesiology score (ASA) grade (P < 0.01) and less comorbidity (P < 0.01), but were more likely to be current smokers (P < 0.01). Patients with CD were more frequently operated on by colorectal surgeons (P < 0.01) and frequently underwent ileocecal resection (P < 0.01) with higher rate of de-functioning/primary stoma construction (P < 0.01). Thirty-day post-operative mortality occurred exclusively in the CC group (66/2515, 2.3%). In multivariate analyses, the risk of post-operative complications was similar in the two groups (OR 0.80, 95%CI: 0.54-1.17; P = 0.25). Patients with CD had a significantly longer LOS (Geometric mean 0.87, 95%CI: 0.79-0.95; P < 0.01). There was no difference in re-admission rates. The audit did not collect data on post-operative enhanced recovery protocols that are implemented in the different participating centers.CONCLUSIONPatients with CD were younger, with lower ASA grade, less comorbidity, operated on by experienced surgeons and underwent less radical resection but had a longer LOS than patients with CC although complication's rate was not different between the two groups

    The impact of stapling technique and surgeon specialism on anastomotic failure after right?sided colorectal resection: an international multicentre, prospective audit

    Get PDF
    Aim There is little evidence to support choice of technique and configuration for stapled anastomoses after right hemicolectomy and ileocaecal resection. This study aimed to determine the relationship between stapling technique and anastomotic failure. Method Any unit performing gastrointestinal surgery was invited to contribute data on consecutive adult patients undergoing right hemicolectomy or ileocolic resection to this prospective, observational, international, multicentre study. Patients undergoing stapled, side?to?side ileocolic anastomoses were identified and multilevel, multivariable logistic regression analyses were performed to explore factors associated with anastomotic leak. Results One thousand three hundred and forty?seven patients were included from 200 centres in 32 countries. The overall anastomotic leak rate was 8.3%. Upon multivariate analysis there was no difference in leak rate with use of a cutting stapler for apical closure compared with a noncutting stapler (8.4% vs 8.0%, OR 0.91, 95% CI 0.54–1.53, P = 0.72). Oversewing of the apical staple line, whether in the cutting group (7.9% vs 9.7%, OR 0.87, 95% CI 0.52–1.46, P = 0.60) or noncutting group (8.9% vs 5.7%, OR 1.40, 95% CI 0.46–4.23, P = 0.55) also conferred no benefit in terms of reducing leak rates. Surgeons reporting to be general surgeons had a significantly higher leak rate than those reporting to be colorectal surgeons (12.1% vs 7.3%, OR 1.65, 95% CI 1.04–2.64, P = 0.04). Conclusion This study did not identify any difference in anastomotic leak rates according to the type of stapling device used to close the apical aspect. In addition, oversewing of the anastomotic staple lines appears to confer no benefit in terms of reducing leak rates. Although general surgeons operated on patients with more high?risk characteristics than colorectal surgeons, a higher leak rate for general surgeons which remained after risk adjustment needs further exploration

    Relationship between method of anastomosis and anastomotic failure after right hemicolectomy and ileo-caecal resection: an international snapshot audit

    Get PDF
    Aim: The anastomosis technique used following right-sided colonic resection is widely variable and may affect patient outcome. This study aimed to assess the association between leak and anastomosis technique (stapled vs handsewn). Method: This was a prospective, multicentre, international audit including patients undergoing elective or emergency right hemicolectomy or ileo-caecal resection operations over a 2-month period in early 2015. The primary outcome measure was the presence of anastomotic leak within 30\ua0days of surgery, determined using a prespecified definition. Mixed effects logistic regression models were used to assess the association between leak and anastomosis method, adjusting for patient, disease and operative cofactors, with centre included as a random-effect variable. Results: This study included 3208 patients, of whom 78.4% (n\ua0=\ua02515) underwent surgery for malignancy and 11.7% (n\ua0=\ua0375) underwent surgery for Crohn's disease. An anastomosis was performed in 94.8% (n\ua0=\ua03041) of patients, which was handsewn in 38.9% (n\ua0=\ua01183) and stapled in 61.1% (n\ua0=\ua01858). Patients undergoing handsewn anastomosis were more likely to be emergency admissions (20.5% handsewn vs 12.9% stapled) and to undergo open surgery (54.7% handsewn vs 36.6% stapled). The overall anastomotic leak rate was 8.1% (245/3041), which was similar following handsewn (7.4%) and stapled (8.5%) techniques (P\ua0=\ua00.3). After adjustment for cofactors, the odds of a leak were higher for stapled anastomosis (adjusted OR\ua0=\ua01.43; 95% CI: 1.04\u20131.95; P\ua0=\ua00.03). Conclusion: Despite being used in lower-risk patients, stapled anastomosis was associated with an increased anastomotic leak rate in this observational study. Further research is needed to define patient groups in whom a stapled anastomosis is safe

    The relationship between method of anastomosis and anastomotic failure after right hemicolectomy and ileo-caecal resection: an international snapshot audit.

    Get PDF
    BACKGROUND: Anastomosis technique following right sided colonic resection is widely variable and may affect patient outcomes. This study aimed to assess the association between leak and anastomosis technique (stapled versus handsewn) METHODS: This was a prospective, multicentre, international audit including patients undergoing elective or emergency right hemicolectomy or ileo-caecal resection operations over a two-month period in early 2015. The primary outcome measure was the presence of anastomotic leak within 30 days of surgery, using a pre-specified definition. Mixed effects logistic regression models were used to assess the association between leak and anastomosis method, adjusting for patient, disease and operative cofactors, with centre included as a random effect variable. RESULTS: This study included 3208 patients, of whom 78.4% (n=2515) underwent surgery for malignancy and 11.7% (n=375) for Crohn's disease. An anastomosis was performed in 94.8% (n=3041) of patients, which was handsewn in 38.9% (n=1183) and stapled in 61.1% (n=1858) cases. Patients undergoing handsewn anastomosis were more likely to be emergency admissions (20.5% handsewn versus 12.9% stapled) and to undergo open surgery (54.7% versus 36.6%). The overall anastomotic leak rate was 8.1% (245/3041), which was similar following handsewn (7.4%) and stapled (8.5%) techniques (p=0.3). After adjustment for cofactors, the odds of a leak were higher for stapled anastomosis (adjusted odds ratio 1.43, 95% confidence interval 1.04-1.95, p=0.03). DISCUSSION: Despite being used in lower risk patients, stapled anastomosis was associated with an increased anastomotic leak rate in this observational study. Further research is needed to define patient groups in whom a stapled anastomosis is safe. This article is protected by copyright. All rights reserve
    corecore