21 research outputs found
Virtual palaeontology: the effects of mineral composition and texture of fossil shell and hosting rock on the quality of X-ray microtomography (XMT) outcomes using Palaeozoic brachiopods
X-ray microtomography (XMT) has become a popular tool for detailed investigations of a diverse range of fossils. However, XMT has not always guaranteed a satisfactory result, as the resolution of XMT images critically depends on the contrast between the fossil and its hosting rock. In this paper, XMT was applied to 11 Palaeozoic brachiopod specimens selected from a range of sedimentary rocks in order to investigate the extent of effects of mineral composition and texture in the rock and fossil shell on the quality of XMT outcomes. Our study shows that sufficient contrast in mineral composition and texture between the brachiopod shell and its infilling material is required to reproduce high-quality XMT results. Specifically, brachiopod specimens with their original calcium carbonate shell, infilled mainly with quartz grains, appear to produce the best XMT results characterized by sharply defined shell internal structures. We also found that diagenesis is significant in determining the XMT quality. Diagenetic processes including silicification and recrystallization in the brachiopod shell and/or the infilling material generally tends to diminish the resolution of the XMT results, although this impact is considerably complicated by the degree and aspect of diagenesis. Another factor of minor significance concerns the presence of bioclasts scattered in the hosting sediment that potentially could be confused with genuine shell internal structures
A giant stem-group chaetognath
Chaetognaths, with their characteristic grasping spines, are the oldest known pelagic predators, found in the lowest Cambrian (Terreneuvian). Here, we describe a large stem chaetognath, Timorebestia koprii gen. et sp. nov., from the lower Cambrian Sirius Passet Lagerstätte, which exhibits lateral and caudal fins, a distinct head region with long antennae and a jaw apparatus similar to Amiskwia sagittiformis. Amiskwia has previously been interpreted as a total-group chaetognathiferan, as either a stem-chaetognath or gnathostomulid. We show that T. koprii shares a ventral ganglion with chaetognaths to the exclusion of other animal groups, firmly placing these fossils on the chaetognath stem. The large size (up to 30 cm) and gut contents in T. koprii suggest that early chaetognaths occupied a higher trophic position in pelagic food chains than today
A giant stem-group chaetognath.
Chaetognaths, with their characteristic grasping spines, are the oldest known pelagic predators, found in the lowest Cambrian (Terreneuvian). Here, we describe a large stem chaetognath, gen. et sp. nov., from the lower Cambrian Sirius Passet Lagerstätte, which exhibits lateral and caudal fins, a distinct head region with long antennae and a jaw apparatus similar to . has previously been interpreted as a total-group chaetognathiferan, as either a stem-chaetognath or gnathostomulid. We show that shares a ventral ganglion with chaetognaths to the exclusion of other animal groups, firmly placing these fossils on the chaetognath stem. The large size (up to 30 cm) and gut contents in suggest that early chaetognaths occupied a higher trophic position in pelagic food chains than today
Metamorphism obscures primary taphonomic pathways in the early Cambrian Sirius Passet Lagerstätte, North Greenland
Correct interpretation of soft-bodied fossils relies on a thorough understanding of their taphonomy. While the focus has often been on the primary roles of decay and early diagenesis, the impacts of deeper burial and metamorphism on fossil preservation are less well understood. We document a sequence of late-stage mineral replacements in panarthropod fossils from the Sirius Passet Lagerstätte (North Greenland), an important early Cambrian Burgess Shale–type (BST) biota. Muscle and gut diverticula were initially stabilized by early diagenetic apatite, prior to being pervasively replaced by quartz and then subordinate chlorite, muscovite, and chloritoid during very low- to low-grade metamorphism. Each new mineral replicates the soft tissues with different precision and occurs in particular anatomical regions, imposing strong biases on the biological information retained. Muscovite and chloritoid largely obliterate the tissues’ original detail, suggesting that aluminum-rich protoliths may have least potential for conserving mineralized soft tissues in metamorphism. Overall, the fossils exhibit a marked shift toward mineralogical equilibration with the matrix, obscuring primary taphonomic modes. Sequential replacement of the phosphatized soft tissues released phosphorus to form new accessory monazite (and apatite and xenotime), whose presence in other BST biotas might signal the prior, more widespread, occurrence of this primary mode of preservation. Our results provide critical context for interpreting the Sirius Passet biota and for identifying late-stage overprints in other biotas
ASSESSING THE VARIABILITY IN ETHNIC GROUP DIFFERENCES ON A POLICE OFFICER SELECTION TEST
Aggregating data across several test administrations is a useful strategy for increasing the statistical power of adverse impact analysis. Typically, before such an analysis is conducted, a test of homogeneity is conducted to ensure that the degree of adverse impact is consistent across samples. An alternative approach would be to use hierarchical linear modeling to estimate the average and variability in adverse impact. The current study explored the patterns of variability of adverse impact in a police officer selection test across test administrations, departments, and geographic regions. Significant mean test score differences were found between African-American and White test takers. Further, the size of mean group differences varied significantly across test administration and departments, but not between geographic regions. The implications of these findings for scientists and practitioners alike are discussed.M.S. in Psychology, May 201
Development of service standards and manpower calculation criteria for hospital clinical pharmacies in South Korea: a survey-based study
Abstract Background After the revision of the Korean Pharmaceutical Affairs Act, the certification of specialized pharmacists is scheduled to be legally recognized in 2023. Considering that the specialized pharmacist certification was developed based on the working model of hospital clinical pharmacists, it is necessary to establish standards for clinical pharmacists in hospitals and to calculate appropriate manpower. Through this study, we aim to establish practical standards for clinical pharmacists and propose a method for calculating staffing levels based on an investigation of actual workloads. Methods This survey-based study consisted of two phases. In the first phase, a literature review was conducted to establish standards for clinical pharmacy services, and tasks in relevant literature were classified to identify clinical pharmacy service tasks that are applicable to the practice of Korean hospitals. Additionally, a preliminary survey was conducted to investigate the essential tasks. In the second phase of the investigation, a multicenter survey was conducted targeting pharmacists in facilities with more than 1,000 beds to explore their perceptions and actual workloads related to tasks. Results According to the standards for clinical pharmacists in Korea, clinical pharmacy services consist of a total of 23 tasks, of which 16 have been identified as essential tasks. Essential tasks accounted for 93% of the total tasks in clinical pharmacy services. The average full-time equivalent (FTE) through workload calculation was 2.5 ± 1.9 for each field, while the FTE allocated to actual practice was 2.1 ± 1.6. The distribution of each type of clinical pharmacy service was as follows: 77% for medication therapy management, 13% for medication education, 8% for multidisciplinary team activities, and 3% for medication use evaluation. Conclusion This study identified essential tasks common to clinical pharmacy services across different healthcare institutions. However, the FTE of clinical pharmacists in actual practice was insufficient compared to the required amount. In order to establish and expand clinical pharmacy services in a hospital, it is necessary to ensure an adequate workforce for essential tasks
Comparison of Diagnostic Performance of Ultrasonography and Magnetic Resonance Enterography in the Assessment of Active Bowel Lesions in Patients with Crohn’s Disease: A Systematic Review and Meta-Analysis
We aimed to evaluate and compare the diagnostic performances of ultrasonography (US) and magnetic resonance enterography (MRE) in assessing active bowel lesions in patients with Crohn’s disease (CD). Materials and Methods: We searched PubMed and EMBASE for studies in which US and MRE were used to assess active bowel lesions in CD patients. Bivariate random effect meta-analytic methods were used to estimate pooled sensitivity, specificity, and hierarchical summary receiver operating characteristic (HSROC) curves. We performed a meta-regression analysis to explore the source of study heterogeneity. Results: Eleven studies involving 752 patients were included. US exhibited a pooled sensitivity of 86% (95% confidence interval (CI) 72–94), pooled specificity of 88% (95% CI 78–94), and HSROC of 0.93 in 10 studies. MRE exhibited a pooled sensitivity of 88% (95% CI 76–95), pooled specificity of 87% (95% CI 73–95), and an HSROC of 0.94 in eight studies. In seven studies comparing the diagnostic performances of US and MRE, the summary sensitivity of US and MRE were 86% (95% CI 65–96, I2 = 92.1) and 86% (95% CI 72–93, I2 = 88.1) (p = 0.841), respectively. The summary specificity of US and MRE were 87% (95% CI 78–93, I2 = 79.8%) and 84% (72–90, I2 = 72.5%) (p = 0.431), respectively, which showed no statistical differences. On meta-regression analysis, studies from Europe (p = 0.002), those that used linear US probes (p = 0.012), those on small bowel lesions (p = 0.01), and those with outcomes as combined features (active inflammation) reported higher US sensitivity than those from other regions, those that used both linear and convex US probes, those on small and large bowels, and those with outcome as one feature (bowel wall thickening or ulcer). Studies with pediatric patients (p = 0.001), those with reference standards including US (p = 0.001), and outcomes as combined features (p = 0.01) reported higher MRE specificity than those with adult populations, reference standards other than the US, and outcomes as one feature. Conclusions: In spite of considerable heterogeneity in the included studies, both US and MRE can diagnose active bowel lesions with comparable diagnostic accuracy in patients with CD. The study region, type of US probe, lesion location, investigated outcome for US sensitivity and study population, reference standards, and investigated outcomes for MRE specificity were potential sources of heterogeneity
Impact of prior mammograms on combined reading of digital mammography and digital breast tomosynthesis
Decision Tree Algorithm-Based Prediction of Vulnerability to Depressive and Anxiety Symptoms in Caregivers of Children With Glaucoma
PURPOSE: Development and validation of a decision tree model (DTM) for prediction of mental health status in Korean caregivers of children with glaucoma. DESIGN: Cross-sectional study. METHODS: Caregivers of children younger than 18 years with diagnosed primary childhood glaucoma (n = 42), secondary childhood glaucoma (n = 51), and glaucoma suspect (GS; n = 36) were prospectively enrolled at Seoul National University Children's Hospital, Seoul, Korea. The participants completed 2 questionnaires, the 9-item Patient Health Questionnaire (PHQ-9) and the 7-item Generalized Anxiety Disorder (GAD-7) Assessment. A DTM analysis for discrimination of those with moderate-to-severe depressive (PHQ-9 score >= 10) and anxiety (GAD-7 score >= 11) symptoms was performed with recursive partitioning algorithms based on the obtained clinical, demographic, and socioeconomic data. RESULTS: The mean PHQ-9 and GAD-7 scores did not significantly differ among the 3 groups ( P = .823 for PHQ-9 score; P = .730 for GAD-7 score). The DTM's balanced accuracies were 0.875 (95% CI = 0.778-0.972) for the PHQ-9 score and 0.880 (95% CI = 0.800-0.960) for theGAD-7 score. The DTM of the PHQ-9 revealed that in caregivers of children with glaucoma, depressive symptoms should be strongly suspected when (1) the child has undergone more than 2 glaucoma surgeries; or (2) the visual acuity (VA, converted to logarithm of minimum angle of resolution [log -MAR]) in the better eye is worse than 0.4 if the child has had only 1 or no surgery. CONCLUSIONS: Evaluation of the number of glaucoma surgeries and VA in the better eye can be a useful decision support tool in predicting mental illness in caregivers of children with glaucoma. ((C) 2022 Elsevier Inc. All rights reserved.)N
Prognostic factors of cytomegalovirus retinitis after hematopoietic stem cell transplantation.
PurposeTo identify the visual prognostic factors in patients with cytomegalovirus (CMV) retinitis after hematopoietic stem cell transplantation (HSCT).MethodsThis retrospective cohort study included 4241 patients who underwent HSCT from April 1, 2010 to March 31, 2019 at Seoul St. Mary's Hospital. Of them, 1063 patients presented CMV viremia, and 67 patients (93 eyes) were diagnosed with CMV retinitis. We enrolled 66 patients (91 eyes). The main outcomes included the initial best-corrected visual acuity (BCVA), BCVA at the diagnosis of retinitis and last visit, involved retinal zone, peak CMV DNA levels in the peripheral blood and aqueous humor, time between HSCT and the diagnosis of retinitis, time between the diagnosis of viremia and retinitis, complications, recurrence, survival, and so on.ResultsThe mean BCVA (logarithm of the minimum angle of resolution) values before HSCT, at the time of retinitis diagnosis, and at the last visit were 0.041 ± 0.076, 0.262 ± 0.529, and 0.309 ± 0.547, respectively. Multiple regression analysis revealed that the involved zone (P = 0.001), time between HSCT and retinitis diagnosis (P = 0.019), and survival status (P = 0.001) were associated with the final visual acuity.ConclusionsThe final visual prognosis was worse in patients with greater invasion of the central retinal zone, those with a longer interval between HSCT and the diagnosis of retinitis, and those who died. Prompt diagnosis of CMV retinitis through periodic fundus examinations of patients with CMV viremia can prevent severe vision loss. Once CMV viremia is confirmed, we recommend fundus examinations to be immediately performed and repeated every 2 weeks for at least 2 months, even if the CMV DNA titer in the peripheral blood becomes negative