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The IRMM-1027 Large-sized dried (LSD) spikes are certified reference materials applied to measure the uranium and plutonium content of dissolved fuel solutions using isotope dilution mass spectrometry. High quality starting metals of uranium and plutonium are dissolved to produce a stock solution, which is dispensed into individual vials and dried down. The present spikes are mixtures of typically 50 mg 20% enriched U and 2 mg enriched 239Pu as dried nitrates, conditioned in an organic substance for stability. Each vial of an IRMM-1027 LSD spike comes with certified masses of uranium (235U and 238U) and 239Pu and isotopic composition with associated uncertainty. This article will discuss major developments since the production of the first batch of LSD spikes and will reflect on the current preparation and certification approaches.

Research Findings: This study used data from a large-scale kindergarten entry assessment (KEA) to understand how well two state screening measures, administered at school entry, predicted the first...

Background Catheter ablations have been traditionally performed with the use of fluoroscopic guidance, which exposes the patient and staff to the inherent risks of radiation. We have developed techniques to eliminate the use of fluoroscopy during cardiac ablations and have been performing completely fluoroless catheter ablations on our patients for over 5 years. Methods We present a retrospective analysis of the safety, efficacy, and feasibility data from 500 consecutive patients who underwent nonfluoroscopic catheter ablation, targeting a total of 639 arrhythmias, including atrioventricular reciprocating tachycardia (AVRT), atrioventricular nodal reentrant tachycardia (AVNRT), atrial tachycardia (AT), atrial fibrillation (AF), premature ventricular contractions (PVCs), and ventricular tachycardia (VT). We perform fluoroless ablations using intracardiac electrograms, electroanatomic mapping, and for most cases intracardiac echocardiography. Our experience includes exclusively endocardial cardiac ablations. Results The mean follow-up was 20.5 months. Recurrence rate for AVRT was 6.5%, for AVNRT 2.5%, for macro-reentrant AT 6.4%, for focal AT 5.4%, for AF 22.6%, for PVC 6.7%, and for VT 21.4%. Major complications occurred in five patients (1.0%); minor complications occurred in three patients (0.6%). No deaths occurred. Fluoroscopy was used in one instance, for 0.3 minutes, to confirm venous access. Conclusions Completely fluoroless catheter ablations may be routinely performed for all endocardial ablations without compromising safety, efficacy, or procedural duration.

In patients with nonvalvular atrial fibrillation (NVAF), the impact of left ventricular diastolic function on the risk for left atrial appendage (LAA) thrombus has not been prospectively studied.At two academic medical centers, patients with NVAF were prospectively enrolled to undergo investigational transthoracic echocardiography immediately before clinically indicated transesophageal echocardiography. Mitral inflow E velocity and tissue Doppler septal and lateral mitral annulus velocities (e') were measured, and E/e' ratios were calculated.Among 266 subjects (mean age, 65 years; 32% women), 17 (6.4%) had LAA thrombus. Patients with LAA thrombus had a higher mean CHA2DS2-VASc score (4.6 ± 1.7 vs 3.0 ± 1.8, P .001), a higher mean lateral E/e' ratio (19.4 ± 10.1 vs 10.2 ± 5.6, P .001), and a lower mean lateral e' velocity (7.0 ± 3.2 vs 10.4 ± 3.7 cm/sec, P = .001). There was a good discriminative capacity for E/e' (area under the curve, 0.83; P .001) and e' velocity (area under the curve, 0.76; P = .001). None of the patients with normal E/e' ratios or normal e' velocities had LAA thrombus. Both E/e' (odds ratio, 1.13 per point; 95% CI, 1.06-1.20; P .001) and e' velocity (odds ratio, 0.76 per 1 cm/sec; 95% CI, 0.63-0.92; P = .005) provided independent and incremental predictive value beyond the CHA2DS2-VASc score; however, E/e' provided greater incremental value than e' velocity (P = .036). Analyses using septal and averaged E/e' and septal e' velocity yielded similar results. Diastolic function parameters were also associated with the presence and intensity of left atrial spontaneous echo contrast, a precursor of LAA thrombus.This prospective and concomitant evaluation of diastolic function and LAA thrombus in patients with NVAF demonstrates that E/e' ratio and e' velocity are associated with LAA thrombus, independent of CHA2DS2-VASc score, and may play a role in identifying patients at low risk for LAA thrombus. These data suggest that diastolic function assessment may improve stroke prediction in patients with NVAF.

We sought to determine and prospectively validate, with concomitantly performed transthoracic (TTE) and transesophageal echocardiograms (TEE), a TTE-assessed E/e′ threshold that can be useful in predicting left atrial appendage (LAA) thrombus in patients with nonvalvular atrial fibrillation (NVAF). The retrospective derivation cohort was comprised of 297 patients with NVAF with TTE performed within 1 year of TEE. The validation cohort was comprised of 266 prospectively enrolled patients with TTE performed immediately prior to TEE. LAA thrombus was detected by TEE in 6.4 % of patients in both cohorts. Receiver operating characteristic (ROC) analyses demonstrated a good discriminatory capacity of lateral E/e′ in predicting LAA thrombus in the derivation cohort (AUC 0.72; CI 0.63–0.82; P = 0.001) which was confirmed in the validation cohort (AUC 0.83; CI 0.75–0.91; P < 0.001). In the derivation cohort, ROC curve point-coordinates identified E/e′ thresholds of both 9.0 and 8.0 to be associated with 100 % sensitivity, with specificities of 36 and 30 %, respectively. An E/e′ threshold of ≥8 was selected a priori for prospective validation, and was associated with 100 % sensitivity and 41 % specificity for LAA thrombus, with positive and negative predictive values of 10 and 100 %, respectively, and positive and negative likelihood ratios of 1.69 and 0, respectively. We determined and validated an E/e′ threshold of 8 as a highly sensitive and useful parameter that can aid in identifying patients at very low risk for LAA thrombus and potentially obviate the need for a TEE prior to electrophysiology procedures and restoration of sinus rhythm.

240Pu and 242Pu targets were prepared by the so-called “molecular plating” on an Al backing for cross-section measurements. The total activity of the actinide layer was determined by low-geometry alpha-particle counting. The atomic abundances of the two Pu materials were determined via thermal ionization mass spectrometry. A radiochemical separation was performed by anion exchange prior to the preparation of the layers to prevent interferences with the ingrown daughter nuclide during the characterization and cross-section measurements. The targets were prepared to be used in the project “Metrology for New Generation Nuclear Power Plants” (MetroFission), within the frame of the European Metrology Research Programme, directed to improve the knowledge on neutron cross sections through metrological approaches. For measurements of the 240Pu(n,f) and 242Pu(n,f) cross sections 240Pu and 242Pu targets were produced and mounted in fission chambers. In parallel, 240Pu and 242Pu targets were prepared for the ANDES project (Accurate Nuclear Data for Nuclear Energy Sustainability) for cross-section measurements at the CERN neutron time-of-flight facility n_TOF, and the Van de Graaff laboratories of IRMM and CNRS/CENBG.

Catheter ablations have been traditionally performed with the use of fluoroscopic guidance, which exposes the patient and staff to the inherent risks of radiation. We have developed techniques to eliminate the use of fluoroscopy during cardiac ablations and have been performing completely fluoroless catheter ablations on our patients for over 5 years.We present a retrospective analysis of the safety, efficacy, and feasibility data from 500 consecutive patients who underwent nonfluoroscopic catheter ablation, targeting a total of 639 arrhythmias, including atrioventricular reciprocating tachycardia (AVRT), atrioventricular nodal reentrant tachycardia (AVNRT), atrial tachycardia (AT), atrial fibrillation (AF), premature ventricular contractions (PVCs), and ventricular tachycardia (VT). We perform fluoroless ablations using intracardiac electrograms, electroanatomic mapping, and for most cases intracardiac echocardiography. Our experience includes exclusively endocardial cardiac ablations.The mean follow-up was 20.5 months. Recurrence rate for AVRT was 6.5%, for AVNRT 2.5%, for macro-reentrant AT 6.4%, for focal AT 5.4%, for AF 22.6%, for PVC 6.7%, and for VT 21.4%. Major complications occurred in five patients (1.0%); minor complications occurred in three patients (0.6%). No deaths occurred. Fluoroscopy was used in one instance, for 0.3 minutes, to confirm venous access.Completely fluoroless catheter ablations may be routinely performed for all endocardial ablations without compromising safety, efficacy, or procedural duration.

Purpose Cryothermal ablation (CTA) for atrioventricular nodal reentrant tachycardia (AVNRT) is considered safer than radiofrequency ablation (RFA) since it eliminates the risk of inadvertent AV block. However, it has not been widely adopted due to high late recurrence rate (LRR). In an effort to improve LRR, we evaluated a new approach to cryothermal mapping (CTM): “time to tachycardia termination” (TTT). Methods This single-center study had 88 consecutive patients who underwent CTA using TTT for AVNRT. The CTA catheter was positioned in sinus rhythm at the posteroseptal tricuspid annulus, and then AVNRT was induced. The CTA target site was identified by prompt tachycardia termination in ≤20 s during CTM. Procedural success was defined as no inducible AVNRT and ≤1 single AV nodal echoes. Results Acute procedural success was achieved in 87 of 88 patients (98.9 %) and was similar to prior studies for both CTA and RFA. No permanent AV block was observed. LRR was 3.7 % at a mean follow-up of 19.7 months. LRR was equivalent to that commonly reported for RFA and improved when compared to conventional CTA. Conclusion TTT for CTA of AVNRT provides enhanced safety and similar long-term efficacy when compared to RFA. Based upon this experience, TTT provides an enhancement to conventional CTA that appears to result in improved long-term outcomes. In light of these findings, it seems reasonable to undertake additional randomized trials to determine whether RFA or CTA using TTT is the optimal approach for the catheter ablation of AVNRT.

This commentary describes practical implications of Schmidt's (International Journal of Selection and Assessment, 20, 1–13 (2012)) rationale supporting content validity evidence for cognitive tests. These implications include descriptions of the meaning of six key inferences about local, specific cognitive tests, four of which are supported by the traditional methods of content evidence, and two of which are not. These help clarify the important incremental inference from Schmidt's proposed methodology that cognitive tests supported by content evidence will also be predictive of job performance in the local setting. A caution is raised that content evidence does not support a general inference that local, specific cognitive tests will take on all empirical properties of general cognitive measures. An additional job analysis step is recommended to strengthen the linkage between the specific cognitive job skills/behaviors and the more general theory of general cognitive ability.

In nuclear safeguards, precise and accurate isotopic analyses are needed for two major elements from the nuclear fuel cycle: uranium and plutonium. This can be achieved by Isotope Dilution Mass Spectrometry (IDMS), which is one of the most reliable analytical techniques for the determination of plutonium amount content to a high level of accuracy. In order to achieve reliable isotope measurements isotopic reference materials with certified amount of plutonium and isotopic composition are required. At the Institute for Reference Materials and Measurements (IRMM) various plutonium spike reference materials for isotopes 239Pu, 240Pu, 242Pu and 244Pu are available. This enabled the setup of an inter-calibration campaign inter-linking selected plutonium spikes on a metrological basis applying state-of-the-art measurement procedures. The aim of this campaign is threefold: firstly to perform measurements on selected plutonium spike isotopic reference materials for quality control purposes, secondly to verify the amount content and the isotopic composition of the recently produced IRMM-1027m large sized dried (LSD) spikes and thirdly to demonstrate IRMM’s measurement capabilities for plutonium analysis via external quality tools. The obtained results using various spike isotopic reference materials will be presented and discussed in this paper. The measurement uncertainties of the IDMS results were calculated according to the guide to the expression of uncertainty in measurement (GUM).

A new series of gravimetrically prepared synthetic isotope reference materials, the so-called IRMM-075 series, with n(236U)/n(238U) isotope ratios varying from 10−4 to 10−9 has been prepared and certified. This series is suited for calibration of n(236U)/n(238U) measurements made by various mass spectrometric techniques such as TIMS (Thermal Ionization Mass Spectrometry), ICPMS (Inductively Coupled Plasma Mass Spectrometry), AMS (Accelerator Mass Spectrometry) and RIMS (Resonance Ionization Mass Spectrometry). Natural uranium with low 236U isotope abundance and highly enriched 236U were both purified using well proven chemical methodology. The oxides were calcined into U3O8 in an oven installed in a glove-box with controlled humidity. Primary solutions of the same concentration were prepared by dissolving the oxides of 236U and natural U. From the 236U solution a series of four dilutions was made by weighing. Weighed amounts of the dilutions of 236U and weighed amounts of natural U were mixed to form a set of n(236U)/n(238U) mixtures at a concentration of 1 mg U g−1. Verification of the mixtures IRMM-075/1–6 was performed by TIMS measurements using Faraday collectors and a secondary electron multiplier in combination with an energy filter for improved abundance sensitivity. The results agreed well with the certified values obtained from the gravimetrical mixing calculations. The uncertainties of the calculated isotopic ratios are significantly lower compared to typical uncertainties from mass spectrometric techniques such as TIMS and ICPMS and in particular to AMS and RIMS. The methods for the preparation and mixing of the IRMM-075/1–6 series are described and the certification and verification procedures are reported.

A new series of gravimetrically prepared uranium isotope reference materials, the so-called IRMM-074 series, with the n((235)U)/n((238)U) isotope ratio held constant at unity and the n((233)U)/n((238)U) isotope ratios varying from 1.0 to 10(-6) has been prepared and certified. This series is suited for calibration or secondary electron multipliers used widely in isotope mass spectrometry, in particular for techniques such as thermal ionization mass spectrometry (TIMS), inductively coupled plasma mass spectrometry (ICPMS), accelerator mass spectrometry (AMS) and resonance ionization mass spectrometry (RIMS). The new IRMM-074 was prepared as a replacement for the already exhausted IRMM-072 predecessor series. Uranium materials with high isotopic enrichments of (233)U, (235)U and (211)U were purified using identical methods involving separation on anion and cation column followed by a precipitation as peroxide. The oxides were calcined to convert them to U(3)O(8) simultaneously, in an oven installed in a glove-box that provided a controlled low-humidity environment. The oxides of (235)U and (238)U were weighed and mixed with a mole ratio n((235)U)/n((211)U)=1.0 and then dissolved. The (233)U oxide was dissolved to form a separate solution with the same concentration and from this primary solution three dilutions were made by weighing. A weighed amount of the n((235)U)/n((238)U) solution and weighed amounts of the (233)U solutions were mixed in various proportions in order to achieve n((233)U)/n((238)U) isotope ratios varying from 1.0 to 10(-6). The methods for the preparation, the mixing and the mixing calculations are described. The expanded uncertainties (coverage factor k-2) of the certified isotope ratios for the IRMM-074 series are 0.015% for the n((235)U)/n((231)U) ratio and 0.025% for the n((233)U)/n((238)U) ratios, which constitutes an improvement compared to those of the predecessor IRMM-072 series. In addition, recent observations regarding the linearity response of secondary electron multipliers (SEMs) and suitable reference materials for investigating detector linearity are reviewed. Two measurement procedures for applying the IRMM-072 and IRMM-073 (diluted from the remaining fraction of IRMM-072) series as well as the new IRMM-074 series for assessing SEM linearity are suggested. The procedures are tailor-made for the specific instrumental characteristics of thermal ionization mass spectrometers (TIMS) and multiple-collector inductively coupled plasma mass spectrometers (MC-ICPMS) but can be adapted also for further types of isotope ratio mass spectrometers. (C) 2009 Elsevier B.V. All rights reserved.

This paper offers an organizational perspective about the Pareto-optimality of trade-offs between selection quality and adverse impact reduction described by De Corte, Lievens and Sackett. Based on considerations of culture and human resource strategy, the need to understand the impact of any trade-off, and a desire to compare this approach to alternatives, it is concluded that organizations may be strategically disinclined to implement such trade-offs and, if interested, organizations would desire more information than is available from the accumulated research in this domain. In particular, validity differences between Pareto-optimal composites are not likely to be good indicators of selection quality differences and the comparative effectiveness of alternative approaches is not clear.

Over the past decade an extraordinary increase has been experienced in the practice of B2B online trading. Portals, hubs, brokerages, and in particular electronic marketplaces (e-marketplaces) have emerged as everyday channels for business trading. The decision process behind joining such an e-marketplace, and evaluating which particular ones offer the best mix of services for a particular business's requirements, is not a straightforward undertaking. There are a host of variants on offer, numerous different membership schemes, service ranges, functionality types, product ranges, and technology platforms in existence, so it can prove to be a very confusing process for any prospective company contemplating joining. In earlier work (Hopkins and Kehoe 2006) an interrelationship matrix-based method was developed for evaluating, and rating, the appropriateness of a range of services offered by e-marketplaces in comparison with specific customer requirements. The system was designed to be used not only for evaluating existing e-marketplaces, but also in assisting with the design of new ones, and was intended be of equal value to both buyers and sellers. This paper now describes how the developed system has been tested, in two case study environments, in order to gauge its suitability for e-marketplace evaluation at both component level and sector level.

Prolonged QRS duration (>120 ms), as a marker of ventricular dyssynchrony, is an independent predictor of mortality in systolic heart failure (HF). Little information exists about the characteristics of patients with preserved ejection fractions (EFs) and prolonged QRS (intraventricular conduction defects [IVCDs]). The electronic records of 334 consecutive patients hospitalized with acutely decompensated HF were reviewed. A significant number of patients hospitalized with decompensated HF had preserved EFs with IVCD. They had similar readmission and mortality rates compared with their systolic HF counterparts and higher rates compared with those with preserved EFs without IVCD. These findings and the resulting possible therapeutic interventions (resynchronization) need further analysis in a larger prospective cohort.