Temporal Bias Research Articles

Using injury severity to improve occupational injury trend estimates.

Hospitalization-based estimates of trends in injury incidence are also affected by trends in health care practices and payer coverage that may differentially impact minor injuries. This study assessed whether implementing a severity threshold would improve occupational injury surveillance. Hospital discharge data from four states and a national survey were used to identify traumatic injuries (1998-2009). Negative binomial regression was used to model injury trends with/without severity restriction, and to test trend divergence by severity. Trend estimates were generally biased downward in the absence of severity restriction, more so for occupational than non-occupational injuries. Restriction to severe injuries provided a markedly different overall picture of trends. Severity restriction may improve occupational injury trend estimates by reducing temporal biases such as increasingly restrictive hospital admission practices, constricting workers' compensation coverage, and decreasing identification/reporting of minor work-related injuries. Injury severity measures should be developed for occupational injury surveillance systems.

Estimating sampling biases and measurement uncertainties of AIRS/AMSU-A temperature and water vapor observations using MERRA reanalysis

We use MERRA (Modern Era Retrospective-Analysis for Research Applications) temperature and water vapor data to estimate the sampling biases of climatologies derived from the AIRS/AMSU-A (Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit-A) suite of instruments. We separate the total sampling bias into temporal and instrumental components. The temporal component is caused by the AIRS/AMSU-A orbit and swath that are not able to sample all of time and space. The instrumental component is caused by scenes that prevent successful retrievals. The temporal sampling biases are generally smaller than the instrumental sampling biases except in regions with large diurnal variations, such as the boundary layer, where the temporal sampling biases of temperature can be ± 2 K and water vapor can be 10% wet. The instrumental sampling biases are the main contributor to the total sampling biases and are mainly caused by clouds. They are up to 2 K cold and > 30% dry over midlatitude storm tracks and tropical deep convective cloudy regions and up to 20% wet over stratus regions. However, other factors such as surface emissivity and temperature can also influence the instrumental sampling bias over deserts where the biases can be up to 1 K cold and 10% wet. Some instrumental sampling biases can vary seasonally and/or diurnally. We also estimate the combined measurement uncertainties of temperature and water vapor from AIRS/AMSU-A and MERRA by comparing similarly sampled climatologies from both data sets. The measurement differences are often larger than the sampling biases and have longitudinal variations.

List-level transfer effects in temporal learning: Further complications for the list-level proportion congruent effect

Congruency effects are larger when most trials are congruent relative to incongruent. According to the conflict adaptation account, this proportion congruent effect is due to the decreased attention to words when most of the trials are conflicting. This paper extends on previous work arguing that list-level (contingency-unbiased) proportion congruent effects might be explainable by temporal learning biases. That is, congruency effects are larger in an easier task (i.e., mostly congruent) due to the faster pace of the task. Two non-conflict analogues of the proportion congruent effect are presented, one with a contrast manipulation and another with a contingency manipulation. Critically, both experiments control for potential item-specific temporal learning biases by intermixing biased context and unbiased transfer items. Results show a proportion congruent-like interaction for both item types, supporting the notion of task-wide temporal learning as an explanation for list-level proportion congruency effects. Distributional analyses lend further credence to the temporal learning account by showing that proportion congruent and proportion congruent-like effects are localised in the fastest and intermediate responses.

Bridging Yesterday, Today, and Tomorrow: CEO Temporal Focus, Environmental Dynamism, and Rate of New Product Introduction

Using a multidimensional framework of CEO temporal focus (the degree to which CEOs characteristically devote attention to perceptions of the past, present, and future), we propose that a company's rate of new product introduction (NPI) is predicted by a CEO's focus on each of the three distinct time frames in interaction with environmental dynamism. Based on a longitudinal (from 1996 to 2003) analysis of 221 firms in 19 industries, we show that, in stable environments, new products are introduced faster in firms headed by CEOs with high past focus, high present focus, and low future focus. In dynamic environments, new products are introduced faster in firms headed by CEOs with low past focus, high present focus, and high future focus. These findings demonstrate how CEO temporal attentional bias shapes the rate of NPI.

Distance Effects in Mental Space and Time Travels

Distance Effects in Mental Space and Time Travels

Effects of Piecewise Spatial Smoothing in 4-D SPECT Reconstruction

In nuclear medicine, cardiac gated SPECT images are known to suffer from significantly increased noise owing to limited data counts. Consequently, spatial (and temporal) smoothing has been indispensable for suppressing the noise artifacts in SPECT reconstruction. However, recently we demonstrated that the benefit of spatial processing in motion-compensated reconstruction of gated SPECT (aka 4-D) could be outweighed by its adverse effects on the myocardium, which included degraded wall motion and perfusion defect detectability. In this work, we investigate whether we can alleviate these adverse effects by exploiting an alternative spatial smoothing prior in 4-D based on image total variation (TV). TV based prior is known to induce piecewise smoothing which can preserve edge features (such as boundaries of the heart wall) in reconstruction. However, it is not clear whether such a property would necessarily be beneficial for improving the accuracy of the myocardium in 4-D reconstruction. In particular, it is unknown whether it would adversely affect the detectability of perfusion defects that are small in size or low in contrast. In our evaluation study, we first use Monte Carlo simulated imaging with 4-D NURBS-based cardiac-torso (NCAT) phantom wherein the ground truth is known for quantitative comparison. We evaluated the accuracy of the reconstructed myocardium using a number of metrics, including regional and overall accuracy of the myocardium, accuracy of the phase activity curve (PAC) of the LV wall for wall motion, uniformity and spatial resolution of the LV wall, and detectability of perfusion defects using a channelized Hotelling observer (CHO). For lesion detection, we simulated perfusion defects with different sizes and contrast levels with the focus being on perfusion defects that are subtle. As a preliminary demonstration, we also tested on three sets of clinical acquisitions. From the quantitative results, it was demonstrated that TV smoothing could further reduce the error level in the myocardium in 4-D reconstruction along with motion-compensated temporal smoothing. In contrast to quadratic spatial smoothing, TV smoothing could reduce the noise level in the LV at a faster pace than the increase in the bias level, thereby achieving a net decrease in the error level. In particular, at the same noise level, TV smoothing could reduce the bias by about 30% compared to quadratic smoothing. Moreover, the CHO results indicate that TV could also improve the lesion detectability even when the lesion is small. The PAC results show that, at the same noise level, TV smoothing achieved lower temporal bias, which is also consistent with the improved spatial resolution of the LV in reconstruction. The improvement in blurring effects by TV was also observed in the clinical images.

Mixed Frequency Structural VARs

A mismatch between the time scale of a structural VAR (SVAR) model and that of the time series data used for its estimation can have serious consequences for identification, estimation and interpretation of the impulse response functions. However, the use of mixed frequency data, combined with a proper estimation approach, can alleviate the temporal aggregation bias, mitigate the identification issues, and yield more reliable responses to shocks. The problems and possible remedy are illustrated analytically and with both simulated and actual data.

Reliability and validity of an accele-rometric system for assessing vertical jumping performance.

The validity of an accelerometric system (Myotest©) for assessing vertical jump height, vertical force and power, leg stiffness and reactivity index was examined. 20 healthy males performed 3ד5 hops in place”, 3ד1 squat jump” and 3× “1 countermovement jump” during 2 test-retest sessions. The variables were simultaneously assessed using an accelerometer and a force platform at a frequency of 0.5 and 1 kHz, respectively. Both reliability and validity of the accelerometric system were studied. No significant differences between test and retest data were found (p < 0.05), showing a high level of reliability. Besides, moderate to high intraclass correlation coefficients (ICCs) (from 0.74 to 0.96) were obtained for all variables whereas weak to moderate ICCs (from 0.29 to 0.79) were obtained for force and power during the countermovement jump. With regards to validity, the difference between the two devices was not significant for 5 hops in place height (1.8 cm), force during squat (-1.4 N · kg−1) and countermovement (0.1 N · kg−1) jumps, leg stiffness (7.8 kN · m−1) and reactivity index (0.4). So, the measurements of these variables with this accelerometer are valid, which is not the case for the other variables. The main causes of non-validity for velocity, power and contact time assessment are temporal biases of the takeoff and touchdown moments detection.

Species coexistence and the dynamics of phenotypic evolution in adaptive radiation

Interactions between species can promote evolutionary divergence of ecological traits and social signals, a process widely assumed to generate species differences in adaptive radiation. However, an alternative view is that lineages typically interact when relatively old, by which time selection for divergence is weak and potentially exceeded by convergent selection acting on traits mediating interspecific competition. Few studies have tested these contrasting predictions across large radiations, or by controlling for evolutionary time. Thus the role of species interactions in driving broad-scale patterns of trait divergence is unclear. Here we use phylogenetic estimates of divergence times to show that increased trait differences among coexisting lineages of ovenbirds (Furnariidae) are explained by their greater evolutionary age in relation to non-interacting lineages, and that--when these temporal biases are accounted for--the only significant effect of coexistence is convergence in a social signal (song). Our results conflict with the conventional view that coexistence promotes trait divergence among co-occurring organisms at macroevolutionary scales, and instead provide evidence that species interactions can drive phenotypic convergence across entire radiations, a pattern generally concealed by biases in age.

Impact of a New Senior Emergency Department on Emergency Department Recidivism, Rate of Hospital Admission, and Hospital Length of Stay

Senior (geriatric) emergency departments (EDs) are an emerging phenomenon across the United States, designed to provide greater comfort for elders, screening for common morbidities, and selective contact with social workers. We hypothesize that the senior ED will reduce recidivism, rate of admission, and hospital length of stay. This was a pre/postintervention observational study of seniors (≥65 years) before and after opening of a new senior ED in a large community hospital. Older nonseniors treated during the same periods were included to detect temporal trend bias. Outcomes included admission to the hospital, hospital length of stay, and ED return visits. Cox proportional hazards models, controlling for patient age, sex, triage level, insurance type, admission on the index visit, and hospital length of stay, were used to test association with time to return within 30 and 180 days. Multivariable regression modeling was used to determine whether the intervention was associated with admission on the index visit, and hospital length of stay. There was no significant difference in time to return within 30 days (HR=1.09; 95% confidence interval [CI] 0.95 to 1.23), 180 days (HR=0.99; 95% CI 0.91 to 1.08), or average hospital length of stay. Risk of being admitted on the index visit was lower for seniors treated in the senior ED compared with the regular ED (Relative Risk=0.93; 95% CI 0.89 to 0.98). A new senior ED was not associated with reduced ED recidivism or hospital length of stay, but was associated with decreased rate of admission.

Diagnosis of famine: a discursive contribution

This paper recommends the incorporation of an additional discursive dimension in famine diagnosis that draws on the number of reports referring to famine in the United Nations Office for the Coordination of Humanitarian Affairs (OCHA)'s ReliefWeb database. Present-day diagnostic tools already apply the principle of triangulation with multiple indicators; the addition of a discursive diagnostic dimension would enable even more refined analysis, allowing more forcefully for the incorporation of the aspect of change. The newly devised discursive famine indices are used both to identify famines--in Ethiopia (2000), Malawi (2002), and Somalia (2011)--and to analyse key socioeconomic determinants of famine. The study finds that income (or poverty) together with state fragility appear to be the major determinants of cross-country variations in famine reporting, while political regimes do not appear to have any independent effect. The indices appear largely robust with regard to concerns about cross-country, semantic, and temporal biases.

Temporal Learning and List-Level Proportion Congruency: Conflict Adaptation or Learning When to Respond?

The current report presents a temporal learning account as a potential alternative to the conflict adaptation account of list-level proportion congruent effects in the Stroop paradigm. Specifically, retrieval of information about response times on previous trials influences a participant's preparedness to respond at a similar time on following trials. First, an adaptation of the Parallel Episodic Processing (PEP) model is presented, and a list-level effect is produced with a temporal learning mechanism. Next, linear mixed effect model analyses show that temporal learning biases are present in list-level proportion congruent data. A non-conflict experiment is then presented in which a list-level effect is observed with a contrast, rather than congruency, manipulation. Analyses of the experimental and simulated data could not, however, provide a clear picture of whether temporal learning was the sole contributor to the list-level proportion congruent effect. These results do, however, demonstrate that caution is warranted when interpreting list-level proportion congruent effects.

Notes on the wire: ballads, biases, and borders of performance journalism

Performance plays a lead role in the story of journalism. From the speeches of town criers to the spectacles of television comedians, the news has always relied on performers. Media scholars, however, have largely accounted for journalism’s history with a bias toward space and print at the expense of time and performance. This article argues that corridistas (balladeers) balance the spatial bias of print with the temporal bias of performance in order to preserve the historical connection between music and news. Corridos (news ballads) induce scholars and reporters to rethink the role of objectivity in journalism with methods that show more than one truth. A textual analysis of two ballads from different centuries illuminates the importance and relevance of performance journalism today.

Is there a weekend bias in clutch-initiation dates from citizen science? Implications for studies of avian breeding phenology

Accurate phenology data, such as the timing of migration and reproduction, is important for understanding how climate change influences birds. Given contradictory findings among localized studies regarding mismatches in timing of reproduction and peak food supply, broader-scale information is needed to understand how whole species respond to environmental change. Citizen science-participation of the public in genuine research-increases the geographic scale of research. Recent studies, however, showed weekend bias in reported first-arrival dates for migratory songbirds in databases created by citizen-science projects. I investigated whether weekend bias existed for clutch-initiation dates for common species in US citizen-science projects. Participants visited nests on Saturdays more frequently than other days. When participants visited nests during the laying stage, biased timing of visits did not translate into bias in estimated clutch-initiation dates, based on back-dating with the assumption of one egg laid per day. Participants, however, only visited nests during the laying stage for 25% of attempts of cup-nesting species and 58% of attempts in nest boxes. In some years, in lieu of visit data, participants provided their own estimates of clutch-initiation dates and were asked "did you visit the nest during the laying period?" Those participants who answered the question provided estimates of clutch-initiation dates with no day-of-week bias, irrespective of their answer. Those who did not answer the question were more likely to estimate clutch initiation on a Saturday. Data from citizen-science projects are useful in phenological studies when temporal biases can be checked and corrected through protocols and/or analytical methods.

Evaluation of the effectiveness of simple nuclei-segmentation methods on Caenorhabditis elegans embryogenesis images

BackgroundFor the analysis of spatio-temporal dynamics, various automated processing methods have been developed for nuclei segmentation. These methods tend to be complex for segmentation of images with crowded nuclei, preventing the simple reapplication of the methods to other problems. Thus, it is useful to evaluate the ability of simple methods to segment images with various degrees of crowded nuclei.ResultsHere, we selected six simple methods from various watershed based and local maxima detection based methods that are frequently used for nuclei segmentation, and evaluated their segmentation accuracy for each developmental stage of the Caenorhabditis elegans. We included a 4D noise filter, in addition to 2D and 3D noise filters, as a pre-processing step to evaluate the potential of simple methods as widely as possible. By applying the methods to image data between the 50- to 500-cell developmental stages at 50-cell intervals, the error rate for nuclei detection could be reduced to ≤ 2.1% at every stage until the 350-cell stage. The fractions of total errors throughout the stages could be reduced to ≤ 2.4%. The error rates improved at most of the stages and the total errors improved when a 4D noise filter was used. The methods with the least errors were two watershed-based methods with 4D noise filters. For all the other methods, the error rate and the fraction of errors could be reduced to ≤ 4.2% and ≤ 4.1%, respectively. The minimum error rate for each stage between the 400- to 500-cell stages ranged from 6.0% to 8.4%. However, similarities between the computational and manual segmentations measured by volume overlap and Hausdorff distance were not good. The methods were also applied to Drosophila and zebrafish embryos and found to be effective.ConclusionsThe simple segmentation methods were found to be useful for detecting nuclei until the 350-cell stage, but not very useful after the 400-cell stage. The incorporation of a 4D noise filter to the simple methods could improve their performances. Error types and the temporal biases of errors were dependent on the methods used. Combining multiple simple methods could also give good segmentations.

Resource Provisioning for Routing with Priorities

In this paper, a novel load balancing technique is proposed to handle biased call request patterns efficiently. The knowledge of call request patterns is used from trace-based analysis; call patterns are affected by various factors such as geographical context, user mobility, network usage patterns and temporal bias. A call routing system is modelled as a network of queues and a provisioning algorithm is developed. The proposed model employs a combination of predictive and reactive provisioning methods. The idea of Capacity Distribution is introduced- a heuristic for heterogeneous capacity allocation among adjacent cell pairs. The proposed model retains simplicity while being able to effectively learn from the variations in call patterns. The performance of the model is evaluated using extensive simulation techniques.

Quantifying temporal ventriloquism in audiovisual synchrony perception

The integration of visual and auditory inputs in the human brain works properly only if the components are perceived in close temporal proximity. In the present study, we quantified cross-modal interactions in the human brain for audiovisual stimuli with temporal asynchronies, using a paradigm from rhythm perception. In this method, participants had to align the temporal position of a target in a rhythmic sequence of four markers. In the first experiment, target and markers consisted of a visual flash or an auditory noise burst, and all four combinations of target and marker modalities were tested. In the same-modality conditions, no temporal biases and a high precision of the adjusted temporal position of the target were observed. In the different-modality conditions, we found a systematic temporal bias of 25-30 ms. In the second part of the first and in a second experiment, we tested conditions in which audiovisual markers with different stimulus onset asynchronies (SOAs) between the two components and a visual target were used to quantify temporal ventriloquism. The adjusted target positions varied by up to about 50 ms and depended in a systematic way on the SOA and its proximity to the point of subjective synchrony. These data allowed testing different quantitative models. The most satisfying model, based on work by Maij, Brenner, and Smeets (Journal of Neurophysiology 102, 490-495, 2009), linked temporal ventriloquism and the percept of synchrony and was capable of adequately describing the results from the present study, as well as those of some earlier experiments.

Assessing Historical Archaeology Site Significance in Cultural Resource Management

Archaeologists conducting cultural resource management studies are often confronted with unique challenges in assessing the significance of historic archaeological sites. Archaeological sites dating to the recent past, due to temporal bias, are sometimes casually dismissed as possessing limited research significance or information value. Further, without the benefit of detailed documentary context, the significance of a site might be overlooked during significance evaluation. In the following article, suggestions are offered for assessing the significance of historical archaeology sites encountered during cultural resource management studies.

What determines species richness of parasitic organisms? A meta‐analysis across animal, plant and fungal hosts

Although a small set of external factors account for much of the spatial variation in plant and animal diversity, the search continues for general drivers of variation in parasite species richness among host species. Qualitative reviews of existing evidence suggest idiosyncrasies and inconsistent predictive power for all proposed determinants of parasite richness. Here, we provide the first quantitative synthesis of the evidence using a meta-analysis of 62 original studies testing the relationship between parasite richness across animal, plant and fungal hosts, and each of its four most widely used presumed predictors: host body size, host geographical range size, host population density, and latitude. We uncover three universal predictors of parasite richness across host species, namely host body size, geographical range size and population density, applicable regardless of the taxa considered and independently of most aspects of study design. A proper match in the primary studies between the focal predictor and both the spatial scale of study and the level at which parasite species richness was quantified (i.e. within host populations or tallied across a host species' entire range) also affected the magnitude of effect sizes. By contrast, except for a couple of indicative trends in subsets of the full dataset, there was no strong evidence for an effect of latitude on parasite species richness; where found, this effect ran counter to the general latitude gradient in diversity, with parasite species richness tending to be higher further from the equator. Finally, the meta-analysis also revealed a negative relationship between the magnitude of effect sizes and the year of publication of original studies (i.e. a time-lag bias). This temporal bias may be due to the increasing use of phylogenetic correction in comparative analyses of parasite richness over time, as this correction yields more conservative effect sizes. Overall, these findings point to common underlying processes of parasite diversification fundamentally different from those controlling the diversity of free-living organisms.

Validation of MOPITT Version 5 thermal‐infrared, near‐infrared, and multispectral carbon monoxide profile retrievals for 2000–2011

AbstractValidation results are reported for the MOPITT (Measurements of Pollution in the Troposphere) “Version 5” (V5) product for tropospheric carbon monoxide (CO) and are compared to results for the “Version 4” product. The V5 retrieval algorithm introduces (1) a method for reducing retrieval bias drift associated with long‐term instrumental degradation, (2) a more exact representation of the effects of random errors in the radiances and, for the first time, (3) the use of MOPITT's near‐infrared (NIR) radiances to complement the thermal‐infrared (TIR) radiances. Exploiting TIR and NIR radiances together facilitates retrievals of CO in the lowermost troposphere. V5 retrieval products based (1) solely on TIR measurements, (2) solely on NIR measurements and (3) on both TIR and NIR measurements are separately validated and analyzed. Actual retrieved CO profiles and total columns are compared with equivalent retrievals based on in situ measurements from (1) routine NOAA aircraft sampling mainly over North America and (2) the “HIAPER Pole to Pole Observations” (HIPPO) field campaign. Particular attention is focused on the long‐term stability and geographical uniformity of the retrieval errors. Results for the retrieved total column clearly indicate reduced temporal bias drift in the V5 products compared to the V4 product, and do not exhibit a positive bias in the Southern Hemisphere, which is evident in the V4 product.