Ancient coastlines of the Black Sea and conditions for human presence – Black Sea expedition 2011

Project DO 02-337, an expedition on the RV Akademik, took place during June 2011 with financial support from the Bulgarian Science Fund. The location for this expedition was the Western Black Sea. 17 core and 8 grapple organic seabed samples were taken. The initial core samples were extracted from the submerged shorelines with subsequent ones taken from deeper water. So submerged shoreline was mapped, samples for dating, isotope analysis and pollen sampling were taken.Проект ДО 02-337, експедиція у східну частину Чорного моря на н/с «Академік» відбулася в червні 2011 року за фінансової підтримки Болгарського наукового фонду. Відібрано 17 проб трубкою і 8 проб драгою. Зразки відбиралися із затопленої берегової лінії, відібрано зразки для датування, ізотопного і пилкового аналізів.Проект ДО 02-337, экспедиция в восточную часть Черного моря на н/с «Академик» состоялась в июне 2011 г. при финансовой поддержке Болгарского научного фонда. Отобраны 17 проб трубкой и 8 проб драгой. Образцы отбирались из затопленной береговой линии, отобраны образцы для датирования, изотопного и пыльцевого анализов

A generic nomogram for multinomial prediction models : theory and guidance for construction

Background The use of multinomial logistic regression models is advocated for modeling the associations of covariates with three or more mutually exclusive outcome categories. As compared to a binary logistic regression analysis, the simultaneous modeling of multiple outcome categories using a multinomial model often better resembles the clinical setting, where a physician typically must distinguish between more than two possible diagnoses or outcome events for an individual patient (e.g., the differential diagnosis). A disadvantage of the multinomial logistic model is that the interpretation of its results is often complex. In particular, the calculation of predicted probabilities for the various outcomes requires a series of careful calculations. Nomograms are widely used in studies reporting binary logistic regression models to facilitate the interpretation of the results and allow the calculation of the predicted probability for individuals. Methods and results In this paper we outline an approach for deriving a generic nomogram for multinomial logistic regression models and an accompanying scoring chart that can further simplify the calculation of predicted multinomial probabilities. We illustrate the use of the nomogram and scoring chart and their interpretation using a clinical example. Conclusions The generic multinomial nomogram and scoring chart can be used irrespective of the number of outcome categories that are present

Problems in detecting misfit of latent class models in diagnostic research without a gold standard were shown

OBJECTIVES: The objective of this study was to evaluate the performance of goodness-of-fit testing to detect relevant violations of the assumptions underlying the criticized 'standard' 2-class latent class model. Often used to obtain sensitivity and specificity estimates for diagnostic tests in the absence of a gold reference standard, this model relies on assuming that diagnostic test errors are independent. When this assumption is violated, accuracy estimates may be biased: goodness-of-fit testing is often used to evaluate the assumption and prevent bias. STUDY DESIGN AND SETTING: We investigate the performance of goodness-of-fit testing by Monte Carlo simulation. The simulation scenarios are based on three empirical examples. RESULTS: Goodness-of-fit tests lack power to detect relevant misfit of the standard 2-class latent class model at sample sizes that are typically found in empirical diagnostic studies. The goodness-of-fit tests that are based on asymptotic theory are not robust to the sparseness of data. A parametric bootstrap procedure improves the evaluation of goodness-of-fit in the case of sparse data. CONCLUSION: Our simulation study suggests that relevant violation of the local independence assumption underlying the standard 2-class latent class model may remain undetected in empirical diagnostic studies, potentially leading to biased estimates of sensitivity and specificity

Problems in detecting misfit of latent class models in diagnostic research without a gold standard were shown

OBJECTIVES: The objective of this study was to evaluate the performance of goodness-of-fit testing to detect relevant violations of the assumptions underlying the criticized 'standard' 2-class latent class model. Often used to obtain sensitivity and specificity estimates for diagnostic tests in the absence of a gold reference standard, this model relies on assuming that diagnostic test errors are independent. When this assumption is violated, accuracy estimates may be biased: goodness-of-fit testing is often used to evaluate the assumption and prevent bias. STUDY DESIGN AND SETTING: We investigate the performance of goodness-of-fit testing by Monte Carlo simulation. The simulation scenarios are based on three empirical examples. RESULTS: Goodness-of-fit tests lack power to detect relevant misfit of the standard 2-class latent class model at sample sizes that are typically found in empirical diagnostic studies. The goodness-of-fit tests that are based on asymptotic theory are not robust to the sparseness of data. A parametric bootstrap procedure improves the evaluation of goodness-of-fit in the case of sparse data. CONCLUSION: Our simulation study suggests that relevant violation of the local independence assumption underlying the standard 2-class latent class model may remain undetected in empirical diagnostic studies, potentially leading to biased estimates of sensitivity and specificity

Hybrid myocardial perfusion SPECT/CT coronary angiography and invasive coronary angiography in patients with stable angina pectoris lead to similar treatment decisions

Objectives To evaluate to what extent treatment decisions for patients with stable angina pectoris can be made based on hybrid myocardial perfusion single-photon emission CT (SPECT) and CT coronary angiography (CCTA). It has been shown that hybrid SPECT/CCTA has good performance in the diagnosis of significant coronary artery disease (CAD). The question remains whether these imaging results lead to similar treatment decisions as compared to standalone SPECT and invasive coronary angiography (CA). Methods We prospectively included 107 patients (mean age 62.8 +/- 10.0 years, 69% male) with stable anginal complaints and an intermediate to high pre-test likelihood for CAD. Hybrid SPECT/CCTA was performed prior to CA in all patients. The study outcome was the treatment decision categorised as: no revascularisation, percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). Treatment decisions were made by two interventional cardiologists and one cardiothoracic surgeon Results Revascularisation (PCI or CABG) was indicated in 54 (50%) patients based on SPECT and CA. Percentage agreement of treatment decisions in all patients based on hybrid SPECT/CCTA versus SPECT and CA on the necessity of revascularisation was 92%. Percentage agreement of treatment decisions in patients with matched, unmatched and normal hybrid SPECT/CCTA findings was 95%, 84% and 100%, respectively. Conclusions Panel evaluation shows that patients could be accurately indicated for and deferred from revascularisation based on hybrid SPECT/CCTA

Short-term Outcomes after Spleen-preserving Minimally Invasive Distal Pancreatectomy with or Without Preservation of Splenic Vessels: A Pan-European Retrospective Study in High-volume Centers

Objective: To compare short-term clinical outcomes after Kimura and Warshaw MIDP. Background: Spleen preservation during distal pancreatectomy can be achieved by either preservation (Kimura) or resection (Warshaw) of the splenic vessels. Multicenter studies reporting outcomes of Kimura and Warshaw spleen-preserving MIDP are scarce. Methods: Multicenter retrospective study including consecutive MIDP procedures intended to be spleen-preserving from 29 high-volume centers (≥15 distal pancreatectomies annually) in 8 European countries. Primary outcomes were secondary splenectomy for ischemia and major (Clavien-Dindo grade ≥III) complications. Sensitivity analysis assessed the impact of excluding ("rescue") Warshaw procedures which were performed in centers that typically (>75%) performed Kimura MIDP. Results: Overall, 1095 patients after MIDP were included with successful splenic preservation in 878 patients (80%), including 634 Kimura and 244 Warshaw procedures. Rates of clinically relevant splenic ischemia (0.6% vs 1.6%, P = 0.127) and major complications (11.5% vs 14.4%, P = 0.308) did not differ significantly between Kimura and Warshaw MIDP, respectively. Mortality rates were higher after Warshaw MIDP (0.0% vs 1.2%, P = 0.023), and decreased in the sensitivity analysis (0.0% vs 0.6%, P = 0.052). Kimura MIDP was associated with longer operative time (202 vs 184 minutes, P = 0.033) and less blood loss (100 vs 150 mL, P < 0.001) as compared to Warshaw MIDP. Unplanned splenectomy was associated with a higher conversion rate (20.7% vs 5.0%, P < 0.001). Conclusions: Kimura and Warshaw spleen-preserving MIDP provide equivalent short-term outcomes with low rates of secondary splenectomy and postoperative morbidity. Further analyses of long-term outcomes are needed

Short-Term Outcomes After Spleen-Preserving Minimally Invasive Distal Pancreatectomy With or Without Preservation of Splenic Vessels: A Pan-European Retrospective Study in High-Volume Centers

Objective: To compare short-term clinical outcomes after Kimura and Warshaw minimally invasive distal pancreatectomy (MIDP). Background: Spleen preservation during distal pancreatectomy can be achieved by either preservation (Kimura) or resection (Warshaw) of the splenic vessels. Multicenter studies reporting outcomes of Kimura and Warshaw spleen-preserving MIDP are scarce. Methods: Multicenter retrospective study including consecutive MIDP procedures intended to be spleen-preserving from 29 high-volume centers (≥15 distal pancreatectomies annually) in eight European countries. Primary outcomes were secondary splenectomy for ischemia and major (Clavien-Dindo grade ≥III) complications. Sensitivity analysis assessed the impact of excluding ('rescue') Warshaw procedures which were performed in centers that typically (&gt;75%) performed Kimura MIDP. Results: Overall, 1095 patients after MIDP were included with successful splenic preservation in 878 patients (80%), including 634 Kimura and 244 Warshaw procedures. Rates of clinically relevant splenic ischemia (0.6% vs. 1.6%, p = 0.127) and major complications (11.5% vs 14.4%, p = 0.308) did not differ significantly between Kimura and Warshaw MIDP, respectively. Mortality rates were higher after Warshaw MIDP (0.0% vs. 1.2%, p = 0.023), and decreased in the sensitivity analysis (0.0% vs 0.6%, p = 0.052). Kimura MIDP was associated with longer operative time (202 vs 184 min, p = 0.033) and less blood loss (100 vs 150 ml, p &lt; 0.001) as compared to Warshaw MIDP. Unplanned splenectomy was associated with a higher conversion rate (20.7% vs 5.0%, p &lt; 0.001). Conclusion: Kimura and Warshaw spleen-preserving MIDP provide equivalent short-term outcomes with low rates of secondary splenectomy and postoperative morbidity. Further analyses of long-term outcomes are needed

Short-term Outcomes after Spleen-preserving Minimally Invasive Distal Pancreatectomy with or Without Preservation of Splenic Vessels: A Pan-European Retrospective Study in High-volume Centers

Objective: To compare short-term clinical outcomes after Kimura and Warshaw MIDP. Background: Spleen preservation during distal pancreatectomy can be achieved by either preservation (Kimura) or resection (Warshaw) of the splenic vessels. Multicenter studies reporting outcomes of Kimura and Warshaw spleen-preserving MIDP are scarce. Methods: Multicenter retrospective study including consecutive MIDP procedures intended to be spleen-preserving from 29 high-volume centers (≥15 distal pancreatectomies annually) in 8 European countries. Primary outcomes were secondary splenectomy for ischemia and major (Clavien-Dindo grade ≥III) complications. Sensitivity analysis assessed the impact of excluding ("rescue") Warshaw procedures which were performed in centers that typically (>75%) performed Kimura MIDP. Results: Overall, 1095 patients after MIDP were included with successful splenic preservation in 878 patients (80%), including 634 Kimura and 244 Warshaw procedures. Rates of clinically relevant splenic ischemia (0.6% vs 1.6%, P = 0.127) and major complications (11.5% vs 14.4%, P = 0.308) did not differ significantly between Kimura and Warshaw MIDP, respectively. Mortality rates were higher after Warshaw MIDP (0.0% vs 1.2%, P = 0.023), and decreased in the sensitivity analysis (0.0% vs 0.6%, P = 0.052). Kimura MIDP was associated with longer operative time (202 vs 184 minutes, P = 0.033) and less blood loss (100 vs 150 mL, P < 0.001) as compared to Warshaw MIDP. Unplanned splenectomy was associated with a higher conversion rate (20.7% vs 5.0%, P < 0.001). Conclusions: Kimura and Warshaw spleen-preserving MIDP provide equivalent short-term outcomes with low rates of secondary splenectomy and postoperative morbidity. Further analyses of long-term outcomes are needed