Artifacts In Interpretation Research Articles

Very-early detection of atrial fibrillation after ablation evaluated by a wearable ECG-patch predicts late blanking period recurrence: Preliminary data from a prospective registry

IntroductionAtrial fibrillation (AF) ablation represents a safe and effective procedure to restore sinus rhythm. The idea that post-procedural AF episodes - during theblanking period-are not considered treatment failure has been increasingly challenged. The E-Patch, a single-use adhesive electrode, facilitates extended continuous ECG monitoring for 120 h. This pilot study aims to assess the effectiveness of this ambulatory monitoring device and investigate whether very-early AF recurrence correlates with delayed blanking period ablation outcomes. MethodsWe conducted a single-center, prospective, longitudinal study, including consecutive post-ablation patients monitored with the E-patch. The ability of the device to continuously record was analyzed, as well as the occurrence of AF episodes during external 7-day loop-recorder in the 2nd-month post-ablation. ResultsWe included 40 patients, median age 62 years (IQR 56–70). E-Patch monitoring was obtained for a median of 118 h (IQR 112–120), with no discomfort nor interpretation artefacts. Very-early AF recurrence was detected in 11 (27.5 %) patients, with a median AF burden of 7 % (IQR 6 %–33 %). Late-blanking period AF was detected in 13 (33 %) of theexternal 7-day looprecordings.Of the 11 patients that had very-early AF recurrence, 10 (91 %) had late-blanking AF. Very-early AF detectionshowed77 % (95 % CI 64 %-90 %) sensitivityand 96 % (95 % CI 90–100 %) specificity inpredictinglate-blanking AF, with a non-parametric ROCcurve AUC of 0.903 (95 % 0.797––1.0). ConclusionThe E-Patch was able to detect very-early AF during an extended period. Very-early AF detection emerges as a predictor of AF recurrence during the late blanking period post-ablation.

ECG-patch assessment of atrial fibrillation during the very-early blanking predicts late blanking period recurrence: preliminary data from a prospective registry

Abstract Funding Acknowledgements Type of funding sources: None. Background Ablation of atrial fibrillation (AF) is a procedure that causes significant atrial tissue lesions, with transient, albeit significant tissue oedema and inflammation. These mechanisms may trigger early rhythm abnormalities that do not necessarily correlate with future arrhythmias, and, therefore, evaluation of AF recurrence is currently validated by routine ECG and ambulatory 24h Holter monitoring, only after a 3-month blanking period. However, recent data have shown that AF episodes occurring during the blanking period are common and may predict late AF recurrences. The E-Patch (Bio Tel Heart) is an innovative, thin single-use adhesive electrode with extended continuous ECG monitoring for up to 120h. Aim To assess if continuous extended monitoring in the very-early blanking period can be associated with event recorder data performed in the late blanking period after AF ablation. Methods Single-centre, prospective, longitudinal study, including consecutive patients (P) 24h after AF ablation, monitored with the E-patch. The effectiveness of the device in continuously recording within 5 days after ablation was analyzed, as well as the occurrence of AF episodes during an external 7- day loop-recorder, obtained in the 2nd-month post-ablation. Results A total of 30P were included (57% male, 63±8 years). AF ablation was performed with radiofrequency (RF) energy in 14P and with a balloon of cryoenergy in 16P. All P were in sinus rhythm at the beginning of the recording. The mean number of hours of recording was 113±16, with no discomfort complaints in the use of the device or interpretation artefacts. During the E-patch monitoring, a total of 10P (33%) presented AF (AF burden 6.8% of the recording, IQR 3.0-20%). All 30P underwent an external loop recorder for 7 days 2 months post-ablation, with 40% showing AF periods (> 30 seconds duration). All 10P that had AF detection in the very-early E-patch recording had also recurrence in the 2 nd month of extended 7-day continuous recording. Very- early AF detection had a sensitivity of 83.3% and a specificity of 100% to detect late blanking period AF (ROC 0.916±0.06; 95%CI 080-1.0). Conclusions The use of the E-patch very-early after AF ablation is effective for AF detection and is highly predictive of AF recurrence in the late blanking period. These findings require validation in larger studies to assess the potential of very-early assessment in the determination of a higher risk for AF recurrence.

UV LIGHT INDUCED FLUORESCENCE RECOVERY OF GFP AFTER PHOTOBLEACHING IN MICROSCOPY IMAGING

Fluorescence microscopy has become one of the most important tools for biologists to visualize and study organelles and molecules in a cell. Fluorescent markers are used to visualize specific molecules. One of the most used markers is green fluorescent protein (GFP), which can be expressed along with a protein of interest. However, it is known that the intensity of fluorescence decreases with observation time. To combat this problem, researchers and companies have developed protocols and additives to mitigate photobleaching. In this study, we tested the effects of the three most used culture media on photobleaching and developed a new approach of short-wavelength fluorescence recovery after photobleaching (FRAP). Photobleaching was analyzed by comparing pixel brightness on images taken with a fluorescence microscope. We determined photobleaching of GFP-expressing cells from images taken with a fluorescence microscope by comparing pixel brightness. Statistical analysis was performed to determine the average bleaching for specific culture media. The culture media analyzed had no significant effect on the photobleaching of GFP. However, a brief UV burst (15 sec) restores 50% of the original fluorescence and neither increases ROS nor decreases cell viability. To avoid artifacts in image analysis and interpretation, our study suggests using this simple method of GFP fluorescence recovery with UV light induced FRAP to extend the fluorescence lifetime and imaging of GFP molecules.

Reconstruction of distorted structures in the fault shadow zone based on the fully connected network

Lateral changes in velocity about faults can give rise to fault shadow (FS) zones on time-migrated data volumes, which can result in structural interpretation artifacts in the fault trap reservoir. To address this issue, we have adopted a new reconstruction method of FS distortion structures based on a deep learning fully connected network (FCN). We use the 3D stratigraphic dip attributes to quantitatively delineate the extent of the FS zone. Then, we train a model to construct a nonlinear trend surface based on the structures of the stratigraphic reflectors that fall outside of the shadow zone. Finally, we use this nonlinear trend surface to compensate for the distorted structure within the FS zone. We calibrate our method using synthetic data and find that the method can accurately recover structural data within the FS distortion zone. We then test the effectiveness of our workflow by applying it to recover real FS distortion structures in the Pearl River Mouth Basin of the South China Sea. The results confirm that our method significantly reduces drilling depth errors in the FS zone. Compared to the traditional polynomial fitting method, the multilayer, multiparameter, and flexible nonlinear activation function of FCN is more capable of reconstructing nonlinear geologic structures in the FS zone. We find the FCN-based geologic reconstruction method to be efficient and effective for exploring potential structures in the FS zone and thereby in avoiding the risks of structural failure.

A Python Toolbox for Unbiased Statistical Analysis of Fluorescence Intermittency of Multilevel Emitters.

We report on a Python toolbox for unbiased statistical analysis of fluorescence intermittency properties of single emitters. Intermittency, that is, step-wise temporal variations in the instantaneous emission intensity and fluorescence decay rate properties, is common to organic fluorophores, II–VI quantum dots, and perovskite quantum dots alike. Unbiased statistical analysis of intermittency switching time distributions, involved levels, and lifetimes are important to avoid interpretation artifacts. This work provides an implementation of Bayesian changepoint analysis and level clustering applicable to time-tagged single-photon detection data of single emitters that can be applied to real experimental data and as a tool to verify the ramifications of hypothesized mechanistic intermittency models. We provide a detailed Monte Carlo analysis to illustrate these statistics tools and to benchmark the extent to which conclusions can be drawn on the photophysics of highly complex systems, such as perovskite quantum dots that switch between a plethora of states instead of just two.

Measurement Invariance of the Flourishing Scale among a Large Sample of Canadian Adolescents.

Our aim was to examine measurement invariance of the Flourishing Scale (FS)—a concise measure of psychological wellbeing—across two study samples and by population characteristics among Canadian adolescents. Data were retrieved from 74,501 Canadian secondary school students in Year 7 (2018–2019) of the COMPASS Study and from the original validation of the FS (n = 689). We assessed measurement invariance using a confirmatory factor analysis in which increasingly stringent equality constraints were specified for model parameters between the following groups: study sample (i.e., adolescents vs. adults), gender, grade, and ethno-racial identity. In all models, full measurement invariance of the FS across all sub-groups was demonstrated. Our findings support the validity of the FS for measuring psychological wellbeing among Canadian adolescents in secondary school. Observed differences in FS score among subgroups therefore represent true differences in wellbeing rather than artifacts of differential interpretation.

On Modelling Big Data Guided Supply Chains in Knowledge-Base Geographic Information Systems

We examine the existing goals of business- and geographic - information systems and their influence on logistics and supply chain management systems. Modelling supply chain management systems is held back because of lack of consistent and poorly aligned data with supply chain elements and processes. The issues constraining the decision-making process limit the connectivity between supply chains and geographically controlled database systems. The heterogeneous and unstructured data are added challenges to connectivity and integration processes. The research focus is on analysing the data heterogeneity and multidimensionality relevant to supply chain systems and geographically controlled databases. In pursuance of the challenges, a unified methodological framework is designed with data structuring, data warehousing and mining, visualization and interpretation artefacts to support connectivity and integration process. Multidimensional ontologies, ecosystem conceptualization and Big Data novelty are added motivations, facilitating the relationships between events of supply chain operations. The models construed for optimizing the resources are analysed in terms of effectiveness of the integrated framework articulations in global supply chains that obey laws of geography. The integrated articulations analysed with laws of geography can affect the operational costs, sure for better with reduced lead times and enhanced stock management.

The North West Shelf (NWS), a Digital Petroleum Ecosystem (PDE) in a Big Data Scale

The North West Shelf (NWS) and its associated petroleum systems have varied geographies, geomorphologies and complex geological environments. In spite of the ongoing exploration activities in many sedimentary basins, the appraisal and field development campaigns are challenging. Besides, interpreting the connectivity between petroleum systems is challenging. The heterogeneity and multidimensionality of multi-stacked reservoirs associated with multiple oil and gas fields complicate the data integration process. Volumes and varieties of data existing in these basins are in different scales, sizes and formats, demanding new storage and retrieval methods, emphasizing both data integration and data structuring. Since the data are in terabyte size; the multiple dimensions and domains need to be brought in a single repository, we take advantage of Big Data tools and technologies. In this context, we aim at articulating the digital petroleum ecosystems and petroleum database management systems, with new data modelling, data warehousing and mining, visualization and interpretation artefacts. This approach facilitates the data management not only for individual basins but groups of basins of the NWS. Warehoused cuboid metadata can explore the connections providing new insights in the data interpretation and knowledge of new prospective areas. The multidimensional warehousing repository that supported by cloud computing, data analytics and virtualization features, provide new opportunities for delivering quality and just-in-time online ecosystem services. Other goals are deducing an integrated unified metadata model and characterizing the connectivity among the basins of the NWS and associated oil & gas fields. The study supports the features of PDE and its knowledge management.

Planting and Tending Digital-Nature Hybrids in a Walled Kitchen Garden

This paper presents various digital-nature artifacts designed to support visitor engagement in a National Trust garden environment. While selected critical theory guided the initial design of interpretation artifacts, we discuss how a research through design approach (RtD) and our attendance at the Research through Design (RTD) 2015 conference informed our subsequent design practice, notably in relation to iterations of the artifacts. In particular, we reflect on how each design iteration within the RtD process revealed knowledge about materials, values, engagement and place.

Accessible areas in ecological niche comparisons of invasive species: Recognized but still overlooked

Understanding biological invasions is crucial for their control and prevention. Specially, establishing whether invasive species operate within the constraint of conservative ecological niches, or if niche shifts occur at all commonly as part of the invasion process, is indispensable to identifying and anticipating potential areas of invasion. Ecological niche modeling (ENM) has been used to address such questions, but improvements and debate in study design, model evaluation, and methods are still needed to mature this field. We reanalyze data for Gray Squirrels (Sciurus carolinensis), native to North America, but invasive in Europe. Our main finding was that, when the analysis extent is established carefully based on analogous sets of environmental conditions, all evidence of niche shifts disappears, suggesting that previous reports of niche shifts for this species are artifacts of methods and interpretation, rather than biological reality. Niche conservatism should be tested only within appropriate, similar, environmental spaces that are accessible to both species or populations being compared, thus avoiding model extrapolation related to model transfers. Testing for environmental similarity between native and invaded areas is critical to identifying niche shifts during species invasion robustly, but also in applications of ENM to understanding temporal dimensions of niche dynamics.

KRILLBASE: a circumpolar database of Antarctic krill and salp numerical densities, 1926–2016

Abstract. Antarctic krill (Euphausia superba) and salps are major macroplankton contributors to Southern Ocean food webs and krill are also fished commercially. Managing this fishery sustainably, against a backdrop of rapid regional climate change, requires information on distribution and time trends. Many data on the abundance of both taxa have been obtained from net sampling surveys since 1926, but much of this is stored in national archives, sometimes only in notebooks. In order to make these important data accessible we have collated available abundance data (numerical density, no. m−2) of postlarval E. superba and salp individual (multiple species, and whether singly or in chains). These were combined into a central database, KRILLBASE, together with environmental information, standardisation and metadata. The aim is to provide a temporal-spatial data resource to support a variety of research such as biogeochemistry, autecology, higher predator foraging and food web modelling in addition to fisheries management and conservation. Previous versions of KRILLBASE have led to a series of papers since 2004 which illustrate some of the potential uses of this database. With increasing numbers of requests for these data we here provide an updated version of KRILLBASE that contains data from 15 194 net hauls, including 12 758 with krill abundance data and 9726 with salp abundance data. These data were collected by 10 nations and span 56 seasons in two epochs (1926–1939 and 1976–2016). Here, we illustrate the seasonal, inter-annual, regional and depth coverage of sampling, and provide both circumpolar- and regional-scale distribution maps. Krill abundance data have been standardised to accommodate variation in sampling methods, and we have presented these as well as the raw data. Information is provided on how to screen, interpret and use KRILLBASE to reduce artefacts in interpretation, with contact points for the main data providers. The DOI for the published data set is doi:10.5285/8b00a915-94e3-4a04-a903-dd4956346439.

Big Data Guided Design Science Information System (DSIS) Development for Sustainability Management and Accounting

Sustainability is a dynamic, complex and composite data relationship among geographically distributed human and environment ecosystems. The ecosystems may have strong interactions among their elements and processes, but with dynamic implicit boundaries. Multi-scalable and multidimensional ecosystems have significance based on a commonality of basic structural units and domains. We intend to develop a holistic information system for managing different ecosystems within a sustainability framework/context, using an empirical qualitative and quantitative interpretation and analysis of the measured observations. Design Science Research (DSR) approach is aimed at developing an information system using the volumes of unstructured Big Data observations. Collaborating multiple domains, interpreting and evaluating the commonality, uncovering the connectivity among multiple systems are key aspects of the study. The Design Science Information System (DSIS), evolved from DSR approach is used in solving the ecosystem issues associated with multiple domains, in which the sustainability challenges manifest. In this context, we propose a human-environment-economic ecosystem (HEES) framework consisting of human, environment and economic elements and processes. In broad terms, human, environment and economic domains are conceptualized as different players/agents that operate within a range of sustainability scenarios. This approach recognizes the existing constraints of the systems as well as the emerging knowledge of the boundaries of ecosystems and their connectivity. The connectivity and interaction among the systems are analyzed by data mining, visualization and interpretation artefacts within a sustainability policy framework.

On a Holistic Modeling Approach for Managing Carbon Emission Ecosystems

Effective use of historical volumes of heterogeneous and multidimensional data is a major challenge, especially projects associated with potential applications of carbon emission ecosystems. Data science in these applications becomes tedious when such varied data are accumulated and or distributed in multiple domains. Design, development, and implementation of sustainable geological storages are crucial for managing carbon dioxide (CO2) emissions and its modeling process. The purpose of the research is to address major challenges and how best a robust “ontology-based multidimensional data warehousing and mining” approach can resolve issues associated with carbon ecosystems. The conceptualized relationships deduced among multiple domains, integration of domain ontologies, data mining, visualization, and interpretation artefacts are highlights of the study. Several data, plot, and map views are extracted from metadata storage for interpreting new knowledge on carbon emissions. Statistical mining models describe data attributes’ correlations, patterns, and trends that can help in predicting future forecast of CO2 emissions worldwide.

Reconstruction and visualization of nanoparticle composites by transmission electron tomography

This paper examines the limits of transmission electron tomography reconstruction methods for a nanocomposite object composed of many closely packed nanoparticles. Two commonly used reconstruction methods in TEM tomography were examined and compared, and the sources of various artefacts were explored. Common visualization methods were investigated, and the resulting “interpretation artefacts” ( i.e., deviations from “actual” particle sizes and shapes arising from the visualization) were determined. Setting a known or estimated nanoparticle volume fraction as a criterion for thresholding does not in fact give a good visualization. Unexpected effects associated with common built-in image filtering methods were also found. Ultimately, this work set out to establish the common problems and pitfalls associated with electron beam tomographic reconstruction and visualization of samples consisting of closely spaced nanoparticles.

Realizing the Literate Traveller

A current research project is addressing the problem of finding appropriate geographical information by developing a (geo)information realization resource based upon the concepts of the Literate Traveller. It has as its main goal to provide tools for geographical knowledge building and exploration, by providing conventional spatial information plus geographical interpretation and appreciation artifacts. These artifacts are delivered in an interactive multimedia environment. This research examines the formulation of an initial prototype component to assist in providing geographical knowledge. The prototype is based on a study site in Townsville, Australia, and is being used as a vehicle to explore enhanced spatial information provision through the use of rich media. The research examines new ways to prospect for, discover and disseminate spatial knowledge within an intelligence-briefing context. The paper reports on the concepts behind the design of the application developed for the test site, and presents initial findings from the early evaluation of the prototype.

Hydrogen/Deuterium Scrambling during Quadrupole Time-of-Flight MS/MS Analysis of a Zinc-Binding Protein Domain

It remains an open question as to whether experiments involving collision-induced dissociation (CID) can provide a viable approach for monitoring spatially resolved deuteration levels in electrosprayed polypeptide ions. A number of laboratories reported the successful application of CID following solution-phase H/D exchange (HDX), whereas others found that H/D scrambling precluded site-specific measurements. The aim of the current work is to help clarify the general feasibility of HDX-CID methods, using a 22-residue zinc-bound protein domain (Zn-ZBD) as model system. Metal binding in Zn-ZBD should confer structural rigidity, and the presence of several basic residues should sequester mobile charge carriers in the gas phase. Both of these factors were expected to suppress the extent of scrambling. HDX was carried out by employing rapid on-line mixing, thereby mimicking conditions typically encountered in kinetic pulse-labeling studies. Quadrupole time-of-flight MS/MS of pulse-labeled Zn-ZBD provides high sequence coverage. However, the measured fragment deuteration levels do not correlate with the known H-bonding pattern of Zn-ZBD, suggesting the occurrence of extensive scrambling. Instead of showing a uniform distribution, the fragment ions reveal a distinct nonrandom pattern of deuteration levels. In the absence of prior information, these data could erroneously be ascribed to the presence of protected sites. However, the observed patterns clearly originate from other factors; possibly they are caused by modulations of the amide CID efficiency by kinetic isotope effects. It is concluded that scrambling does not represent the only conceptual problem in HDX-CID studies and that control experiments on uniformly labeled samples are essential for ruling out interpretation artifacts.

Technical issues in electrodiagnostic recording.

Electroretinogram (ERG) and visual-evoked potentials (VEPs) are used in veterinary ophthalmology to assess the functional integrity of the retina and the central visual pathway. The interpretation of altered electrophysiologic potentials in diseases can be of great diagnostic value, although it is important to be aware of technical factors and the limitations of these techniques which may result in over-interpretation and misinterpretation of the recordings, such that they are similar to those found in disease-related electrophysiologic changes. The recorded potentials represent the differences in voltage between the active and reference electrodes. The ground electrode serves as zero. A differential or instrumentation amplifier selectively amplifies signals of interest while rejecting noise. Differences between inputs are amplified, whereas common signals are rejected in a process called common mode rejection (CMR). In order for CMR to be most effective in reducing noise, the electrode impedances should be balanced. Filters are part of the differential amplifier as they remove unwanted noise of a certain frequency. The frequency bandwidth, or passband, is the range of frequencies between low- and high-frequency filter settings that are not filtered out. Major sources of noise that cause interpretation artifacts are power lines, amplifier noise, physiologic activity, electrochemical electrode noise and circular grounds. Noise reduction is achieved with high amplifier input impedance, balanced electrode impedances, CMR, filters and signal averaging. Maintaining electrodes in good condition, achieving proper contact between electrode and animal, and keeping electrode leads short aid in achieving noise reduction.

“The Reality of Repressed Memories” Revisited and Principles of Science

An article in the 1993 issue of the American Psychologist entitled “The reality of repressed memories” (Loftus, 1993) forms the foundation for how many contemporary professionals understand the recovered memory/false memory controversy. The message conveyed to the readership was that recovered memories are by-products of therapy. Paradoxically, the message enjoys wide-ranging influence on the basis of “facts” that lack the rigor of science. Status was established on the basis of speculative theory, artifacts of interpretation, and the power of selectively filtered information. The message illustrates the dilemma posed for readers without personal familiarity with the subject matter, when messages are advanced on the basis of imperfect disclosure of prevailing knowledge. This article revisits the “evidence” and acquaints readers with the many errors of omission and fact that plague the false memory message (Loftus, 1993), and that cloud the science concerning memory and learning.

Potential artifacts in interpretation of differential breakthrough of colloids and dissolved tracers in the context of transport in a zero-valent iron permeable reactive barrier.

Many published studies have used visual comparison of the timing of peak breakthrough of colloids versus conservative dissolved tracers (hereafter referred to as dissolved tracers or tracers) in subsurface media to determine whether they are advected differently, and to elucidate the mechanisms of differential advection. This purely visual approach of determining differential advection may have artifacts, however, due to the attachment of colloids to subsurface media. The attachment of colloids to subsurface media may shift the colloidal peak breakthrough to earlier times, causing an apparent "faster" peak breakthrough of colloids relative to dissolve tracers even though the transport velocities for the colloids and the dissolved tracers may actually be equivalent. In this paper, a peak shift analysis was presented to illustrate the artifacts associated with the purely visual approach in determining differential advection, and to quantify the peak shift due to colloid attachment. This peak shift analysis was described within the context of microsphere and bromide transport within a zero-valent iron (ZVI) permeable reactive barrier (PRB) located in Fry Canyon, Utah. Application of the peak shift analysis to the field microsphere and bromide breakthrough data indicated that differential advection of the microspheres relative to the bromide occurred in the monitoring wells closest to the injection well in the PRB. It was hypothesized that the physical heterogeneity at the grain scale, presumably arising from differences in inter- versus intra-particle porosity, contributed to the differential advection of the microspheres versus the bromide in the PRB. The relative breakthrough (RB) of microspheres at different wells was inversely related to the ionic strength of ground water at these wells, in agreement with numerous studies showing that colloid attachment is directly related to solution ionic strength.

Anatomic variants and artifacts in ERCP interpretation.

ERCP is a complex diagnostic procedure requiring manual dexterity, careful attention to endoscopic and radiographic technique, and correct interpretation of the resulting images. Not surprisingly, the procedure is associated with many potential pitfalls. Many of these are related to normal anatomic pancreatic and biliary variants and to artifacts associated with the examination itself. Knowledge of these variants and artifacts is necessary to perform procedures and interpret the results effectively. Our discussion and illustrations are based on a retrospective review of approximately 1300 ERCP studies performed at a single center during a 2-year period.