Exploration of Context in Widespread and Subjective Application: A Study with Archivists of Rare Repositories in the United States

Characterized by their structure, standards, and unique collections of records, archival repositories have maintained their distinct identities in the field of information science as their practices has evolved and adapted over time. The concept of context has distinct roles in repositories, in theory and practice, but it is also flexible in how it may be precisely described and understood. This study examines the innerworkings of five rare archival repositories as they consider and understand this concept of context and the impact it has within each organization. All archives hold unique records, but this study addresses those with more highly specialized materials. Comparisons are made amongst the interviewed repositories, as well as with archival and information science practices overall. The results display a range of impact in how context influences the archivists and repositories overall, but the rare nature of the records is a driving force in curating and interacting with the repositories’ internal environment and external community.Master of Science in Library Scienc

Anterior Talofibular Ligament and Superior Extensor Ankle Retinaculum Thicknesses: Relationship with Balance

Purpose This study determined if anterior talofibular ligament (ATFL)/superior extensor ankle retinaculum (SEAR) thicknesses are related to dynamic balance in individuals with chronic ankle instability (CAI). Materials and Methods The subjects were 14 males and 15 females (age=24.52±3.46 years). Ankle instability was assessed using the Cumberland Ankle Instability Tool (CAIT) with a cut off score of 25 to define two groups. SonoSite MTurbo (Fugifilm Sonosite, Inc.) musculoskeletal ultrasound (MSKUS) unit was used to assess ATFL and SEAR thicknesses. Dynamic balance was measured with the Y Balance Test (YBT) and two NeuroCom balance tests. Results There were no significant differences in the average ATFL thickness between stable and unstable ankles in those subjects with CAI (0.25±0.03 cm and 0.21±0.05 cm, respectively) or in the SEAR thickness (0.09±0.04 cm and 0.10±0.03 cm, respectively). There were also no significant differences in the right and left ATFL thicknesses (0.23±0.07 cm and 0.21±0.04 cm, respectively) or the SEAR thicknesses (0.09±0.01 cm and 0.09±0.01 cm, respectively) in those without CAI. There were no differences between limbs in composite scores on YBT in those with CAI (p=0.35) and those without CAI (p=0.33). There was a moderate correlation between the left SEAR thickness and the large forward/backward perturbations on the NeuroCom (Natus) motor control test (r=0.51, p=0.006 and r=0.54, p=0.003, respectively). Conclusion There were no differences in the ATFL/SEAR thicknesses or balance measures between or within the groups, likely because CAI is multi-factorial and related to mechanisms other than tissue changes alone. More sensitive technology and a better definition of the measurement process may provide more definitive results

F.A.R.O.G. FORUM, Vol. 9 No. 2

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Le FORUM, Vol. 9 No. 4

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F.A.R.O.G. FORUM, Vol. 9 No. 2

https://digitalcommons.library.umaine.edu/francoamericain_forum/1082/thumbnail.jp

Developmental, cellular, and biochemical basis of transparency in the glasswing butterfly Greta oto

Numerous species of Lepidoptera have transparent wings, which often possess scales of altered morphology and reduced size, and the presence of membrane surface nanostructures that dramatically reduce reflection. Optical properties and anti-reflective nanostructures have been characterized for several ‘clearwing’ Lepidoptera, but the developmental basis of wing transparency is unknown. We apply confocal and electron microscopy to create a developmental time-series in the glasswing butterfly, Greta oto, comparing transparent and non-transparent wing regions. We find that scale precursor cell density is reduced in transparent regions, and cytoskeletal organization differs between flat scales in opaque regions, and thin, bristle-like scales in transparent regions. We also reveal that sub-wavelength nanopillars on the wing membrane are wax-based, derive from wing epithelial cells and their associated microvillar projections, and demonstrate their role in enhancing-anti-reflective properties. These findings provide insight into morphogenesis of naturally organized micro- and nanostructures and may provide bioinspiration for new anti-reflective materials

A comparison of automated atrophy measures across the frontotemporal dementia spectrum: Implications for trials

Background Frontotemporal dementia (FTD) is a common cause of young onset dementia, and whilst there are currently no treatments, there are several promising candidates in development and early phase trials. Comprehensive investigations of neuroimaging markers of disease progression across the full spectrum of FTD disorders are lacking and urgently needed to facilitate these trials. Objective To investigate the comparative performance of multiple automated segmentation and registration pipelines used to quantify longitudinal whole-brain atrophy across the clinical, genetic and pathological subgroups of FTD, in order to inform upcoming trials about suitable neuroimaging-based endpoints. Methods Seventeen fully automated techniques for extracting whole-brain atrophy measures were applied and directly compared in a cohort of 226 participants who had undergone longitudinal structural 3D T1-weighted imaging. Clinical diagnoses were behavioural variant FTD (n = 56) and primary progressive aphasia (PPA, n = 104), comprising semantic variant PPA (n = 38), non-fluent variant PPA (n = 42), logopenic variant PPA (n = 18), and PPA-not otherwise specified (n = 6). 49 of these patients had either a known pathogenic mutation or postmortem confirmation of their underlying pathology. 66 healthy controls were included for comparison. Sample size estimates to detect a 30% reduction in atrophy (80% power; 0.05 significance) were computed to explore the relative feasibility of these brain measures as surrogate markers of disease progression and their ability to detect putative disease-modifying treatment effects. Results Multiple automated techniques showed great promise, detecting significantly increased rates of whole-brain atrophy (pConclusionThis work expands current knowledge and builds on the limited longitudinal investigations currently available in FTD, as well as providing valuable information about the potential of fully automated neuroimaging biomarkers for sporadic and genetic FTD trials

Prominent effects and neural correlates of visual crowding in a neurodegenerative disease population.

Crowding is a breakdown in the ability to identify objects in clutter, and is a major constraint on object recognition. Crowding particularly impairs object perception in peripheral, amblyopic and possibly developing vision. Here we argue that crowding is also a critical factor limiting object perception in central vision of individuals with neurodegeneration of the occipital cortices. In the current study, individuals with posterior cortical atrophy (n=26), typical Alzheimer's disease (n=17) and healthy control subjects (n=14) completed centrally-presented tests of letter identification under six different flanking conditions (unflanked, and with letter, shape, number, same polarity and reverse polarity flankers) with two different target-flanker spacings (condensed, spaced). Patients with posterior cortical atrophy were significantly less accurate and slower to identify targets in the condensed than spaced condition even when the target letters were surrounded by flankers of a different category. Importantly, this spacing effect was observed for same, but not reverse, polarity flankers. The difference in accuracy between spaced and condensed stimuli was significantly associated with lower grey matter volume in the right collateral sulcus, in a region lying between the fusiform and lingual gyri. Detailed error analysis also revealed that similarity between the error response and the averaged target and flanker stimuli (but not individual target or flanker stimuli) was a significant predictor of error rate, more consistent with averaging than substitution accounts of crowding. Our findings suggest that crowding in posterior cortical atrophy can be regarded as a pre-attentive process that uses averaging to regularize the pathologically noisy representation of letter feature position in central vision. These results also help to clarify the cortical localization of feature integration components of crowding. More broadly, we suggest that posterior cortical atrophy provides a neurodegenerative disease model for exploring the basis of crowding. These data have significant implications for patients with, or who will go on to develop, dementia-related visual impairment, in whom acquired excessive crowding likely contributes to deficits in word, object, face and scene perception