Geochemistry of Ekenkpon and Nkporo shales, Calabar flank, SE Nigeria: implications for provenance, transportation history and depositional environment

The Cretaceous Nkporo and Ekenkpon Shales within the Calabar Flank were investigated using Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) and Atomic Emission Spectroscopy (ICP-AES) to deduce the provenance, transportation history and depositional environment. The results show the dominance of SiO2 (45.27 – 46.45%; 44.50 – 54.83%), Al2O3 (22.27 – 23.57%; 19.20 – 20.20%) and Fe2O3 (8.30 – 9.04%; 5.64 – 7.30%) constituting the bulk major oxides of Nkporo and Ekenkpon Shales respectively. The Index of Chemical Variation (ICV) ranges from 0.42 – 0.56 and 0.57– 0.68 for Nkporo and Ekenkpon Shales respectively, suggesting moderate and high degree of weathering. The enrichment of Sr (124 – 350ppm; Nkporo Shale and 176 – 856ppm; Ekenkpon Shale) compared to Post Australian Archean Shale (PAAS; 14.6ppm) could be attributed to feldspars in the source area, and is easily incorporated in the clay minerals of the shales. Also the values of Th and U which are 15.00 – 17.20ppm; 14.6- 23.2ppm and 3.5-4.2ppm; 1.9-6.2ppm respectively in Nkporo and Ekenkpon sediments show enrichment compared to PAAS of 14.6ppm and 3.1ppm for respective values of Th and U. The Eu anomaly of 0.04 to 0.07 suggests felsic source rocks for both formations while plots of TiO2 vs. Al2O3 indicate an intermediate to dominantly felsic granodiorite source for both shales, with little input from felsic volcanic provenance plus traces of quartzose sedimentary rocks. The mobility of Na, Ca, and K due to progressive weathering of the shales is evident in the bivariate plots of Na2O wt% vs. PIA, CaOwt% vs. PIA and K2O vs. PIA. Values of Th/U ratios range from 3.37 – 4.91(Nkporo) and 3.10 – 7.68 (Ekenkpon), indicating moderate to high weathering and reworking of sediments. It is envisaged that the area is associated with passive to active continental margin tectonics, where sediments were mainly sourced from felsic rocks of the adjoining terrain and deposited in oxic, continental to transitional marine environment based on Al2O3– K2O +CaO+MgO-Fe2O3+MgO; AKF plot.KEYWORDS: Cretaceous, Calabar Flank, provenance, transportation history, depositional environment

The European Network for Translational Research in Atrial Fibrillation (EUTRAF): objectives and initial results.

Atrial fibrillation (AF) is the most common sustained arrhythmia in the general population. As an age-related arrhythmia AF is becoming a huge socio-economic burden for European healthcare systems. Despite significant progress in our understanding of the pathophysiology of AF, therapeutic strategies for AF have not changed substantially and the major challenges in the management of AF are still unmet. This lack of progress may be related to the multifactorial pathogenesis of atrial remodelling and AF that hampers the identification of causative pathophysiological alterations in individual patients. Also, again new mechanisms have been identified and the relative contribution of these mechanisms still has to be established. In November 2010, the European Union launched the large collaborative project EUTRAF (European Network of Translational Research in Atrial Fibrillation) to address these challenges. The main aims of EUTRAF are to study the main mechanisms of initiation and perpetuation of AF, to identify the molecular alterations underlying atrial remodelling, to develop markers allowing to monitor this processes, and suggest strategies to treat AF based on insights in newly defined disease mechanisms. This article reports on the objectives, the structure, and initial results of this network

The harm of anticoagulation in patients with low-risk by CHADS2 and reclassified as high-risk by CHA2DS2VASc: inferences from TRAF cohort.

OBJECTIVE: There is a gap in the knowledge concerning oral anticoagulation (OAC) in atrial fibrillation (AF) patients with a non-high risk of stroke. CHA2DS2VASc and CHADS2 scores generated imprecise risk estimates for low risk patients. We aimed to assess OAC in patients with low risk by CHADS2 and reclassified as high-risk by CHA2DS2VASc. PATIENTS AND METHODS: In this study, retrospective nationwide population-based study, data were obtained from the Turkish claims and utilization management system. Patients with non-valvular AF (n=451,113) between 2007 and 2012 sub-divided into those with a CHA2DS2VASc≥1 and CHADS2=0 (n=41,273) who were off-warfarin (n=29,448) and on-warfarin (n=11,825). Stroke and systemic embolism, major bleeding, all-cause mortality, net clinical benefit (NCB) and ultimate NCB (UNCB) were assessed. RESULTS: Of the total cohort (mean age 66.1 ± 14.1 years, 56.1% female), CHA2DS2VASc improved the net reclassification index of observed 5-year composite thromboembolic endpoint by 6.9% (p<0.05). CHA2DS2VASc reclassified 9.7% low risk patients as high risk. Among reclassified-high-risk category (patients with a CHA2DS2VASc score of ≥1 and CHADS2 score of 0), major bleeding for that prescribed warfarin was 3% and higher than the rate of thromboembolism among those off-warfarin. NCB (-0.035) and UNCB (-0.021) were negative. Death and hospitalization at 1 year were significantly higher for on-warfarin group. CONCLUSIONS: Clinical outcomes, net clinical benefit indices are negative; rates of death and hospitalization were significantly higher for OAC in reclassified category. This emphasizes the importance of greater attention to balancing the risks and benefits of OAC in patients with low risk by CHADS2 and reclassified as high-risk by CHA2DS2VASc

Separately contacted edge states: A new spectroscopic tool for the investigation of the quantum Hall effect

Using an innovative combination of a quasi-Corbino sample geometry and the cross-gate technique, we have developed a method that enables us to separately contact single edge channels in the quantum Hall regime and investigate equilibration among them. Performing 4-point resistance measurements, we directly obtain information on the energetic and geometric structure of the edge region and the equilibration-length for current transport across the Landau- as well as the spin-gap. Based on an almost free choice in the number of participating edge channels and their interaction-length a systematic investigation of the parameter-space becomes possible.Comment: 8 pages, 7 figure

Peri‐ictal responsiveness to the social environment is greater in psychogenic nonepileptic than epileptic seizures

Objective To look for evidence of peri‐ictal social interaction in psychogenic nonepileptic seizures (PNES) and epileptic seizures exploring the notion of PNES as a form of nonverbal communication. Methods Video recordings of typical seizures experienced by patients with epilepsy and PNES were obtained in a naturalistic social setting (residential epilepsy monitoring unit). Video analysis by three nonexpert clinicians identified 18 predefined semiological and interactional features indicative of apparent impairment of consciousness or of peri‐ictal responsiveness to the social environment with assessment of interrater reliability using Fleiss κ. Features were compared between epileptic seizures and PNES. Results One hundred eighty‐nine seizures from 50 participants (24 epilepsy, 18 PNES, eight combined) were analyzed. At least fair (κ > 0.20) interrater agreement was achieved for 14 features. The PNES and epileptic seizures compared were of similar severity in terms of ictal impairment of consciousness (κ = 0.34, odds ratio [OR] = 1.11, 95% confidence interval [CI] = 0.62‐1.96) and responsiveness (κ = 0.52, OR = 1.01, 95% CI = 0.55‐1.86). PNES were more likely to be preceded by attempts to alert others (κ = 0.52, OR = 12.4, 95% CI = 3.2‐47.7, P < .001), to show intensity affected by the presence of others (κ = 0.44, OR = 199.4, 95% CI = 12.0‐3309.9, P < .001), and to display postictal behavior affected by the presence of others (κ = 0.35, OR = 91.1, 95% CI = 17.2‐482.1, P < .001). Significance Nonexpert raters can, with fair to moderate reliability, rate features characterizing ictal impairment of consciousness and responsivity in video recordings of seizures. PNES are associated with greater peri‐ictal responsiveness to the social environment than epileptic seizures. These findings are consistent with a potential communicative function of PNES and could be of differential diagnostic significance

Transcript of The Dory Derby Accident

This story is an excerpt from a longer interview that was collected as part of the Launching through the Surf: The Dory Fleet of Pacific City project. In this story, Don Grotjohn recounts an accident that occurred during a Dory Derby competition

Small bowel MR enterography: problem solving in Crohn’s disease

Magnetic resonance enterography (MRE) is fast becoming the first-line radiological investigation to evaluate the small bowel in patients with Crohn’s disease. It can demonstrate both mural and extramural complications. The lack of ionizing radiation, together with high-contrast resolution, multiplanar capability and cine-imaging make it an attractive imaging modality in such patients who need prolonged follow-up. A key question in the management of such patients is the assessment of disease activity. Clinical indices, endoscopic and histological findings have traditionally been used as surrogate markers but all have limitations. MRE can help address this question. The purpose of this pictorial review is to (1) detail the MRE protocol used at our institution; (2) describe the rationale for the MR sequences used and their limitations; (3) compare MRE with other small bowel imaging techniques; (4) discuss how MRE can help distinguish between inflammatory, stricturing and penetrating disease, and thus facilitate management of this difficult condition

Low-blood lymphocyte number and lymphocyte decline as key factors in COPD outcomes: a longitudinal cohort study

Background: Smokers with and without chronic obstructive pulmonary disease (COPD) are at risk of severe outcomes like exacerbations, cancer, respiratory failure, and decreased survival. The mechanisms for these outcomes are unclear; however, there is evidence that blood lymphocytes (BL) number might play a role. Objective: The objective of this study is to investigate the relationship between BL and their possible decline over time with long-term outcomes in smokers with and without COPD. Methods: In 511 smokers, 302 with COPD (COPD) and 209 without COPD (noCOPD), followed long term, we investigated whether BL number and BL decline over time might be associated with long-term outcomes. Smokers were divided according to BL number in high-BL (=1, 800 cells/µL) and low-BL (<1, 800 cells/µL). Clinical features, cancer incidence, and mortality were recorded during follow-up. BL count in multiple samples and BL decline over time were calculated and related to outcomes. Results: BL count was lower in COPD (1, 880 cells/µL) than noCOPD (2, 300 cells/µL; p < 0.001). 43% of COPD and 23% of noCOPD had low-BL count (p < 0.001). BL decline over time was higher in COPD than noCOPD (p = 0.040). 22.5% of the whole cohort developed cancer which incidence was higher in low-BL subjects and in BL decliners than high-BL (31 vs. 18%; p = 0.001) and no decliners (32 vs. 19%; p = 0.002). 26% in the cohort died during follow-up. Furthermore, low-BL count, BL decline, and age were independent risk factors for mortality by Cox regression analysis. Conclusion: BL count and BL decline are related to worse outcomes in smokers with and without COPD, which suggests that BL count and decline might play a mechanistic role in outcomes deterioration. Insights into mechanisms inducing the fall in BL count could improve the understanding of COPD pathogenesis and point toward new therapeutic measures

Application of the RIMARC algorithm to a large data set of action potentials and clinical parameters for risk prediction of atrial fibrillation

Ex vivo recorded action potentials (APs) in human right atrial tissue from patients in sinus rhythm (SR) or atrial fibrillation (AF) display a characteristic spike-and-dome or triangular shape, respectively, but variability is huge within each rhythm group. The aim of our study was to apply the machine-learning algorithm ranking instances by maximizing the area under the ROC curve (RIMARC) to a large data set of 480 APs combined with retrospectively collected general clinical parameters and to test whether the rules learned by the RIMARC algorithm can be used for accurately classifying the preoperative rhythm status. APs were included from 221 SR and 158 AF patients. During a learning phase, the RIMARC algorithm established a ranking order of 62 features by predictive value for SR or AF. The model was then challenged with an additional test set of features from 28 patients in whom rhythm status was blinded. The accuracy of the risk prediction for AF by the model was very good (0.93) when all features were used. Without the seven AP features, accuracy still reached 0.71. In conclusion, we have shown that training the machine-learning algorithm RIMARC with an experimental and clinical data set allows predicting a classification in a test data set with high accuracy. In a clinical setting, this approach may prove useful for finding hypothesis-generating associations between different parameters. © 2014, International Federation for Medical and Biological Engineering