Formation of Dendritic Spines with GABAergic Synapses Induced by Whisker Stimulation in Adult Mice

AbstractDuring development, alterations in sensory experience modify the structure of cortical neurons, particularly at the level of the dendritic spine. Are similar adaptations involved in plasticity of the adult cortex? Here we show that a 24 hr period of single whisker stimulation in freely moving adult mice increases, by 36%, the total synaptic density in the corresponding cortical barrel. This is due to an increase in both excitatory and inhibitory synapses found on spines. Four days after stimulation, the inhibitory inputs to the spines remain despite total synaptic density returning to pre-stimulation levels. Functional analysis of layer IV cells demonstrated altered response properties, immediately after stimulation, as well as four days later. These results indicate activity-dependent alterations in synaptic circuitry in adulthood, modifying the flow of sensory information into the cerebral cortex

Toward a Regional Classification to Provide a More Inclusive Examination of the Ocean Biogeochemistry of Iron-Binding Ligands

Iron-binding ligands are paramount to understanding iron biogeochemistry and its potential to set the productivity and the magnitude of the biological pump in >30% of the ocean. However, the nature of these ligands is largely uncharacterized and little is known about their sources, sensitivity to photochemistry and biological transformation, or scavenging behavior. Despite many uncertainties, there is no doubt that ligands are produced by a wide range of biotic and abiotic processes, and that the bulk ligand pool encompasses a diverse range of molecules. Despite widespread recognition of the likelihood of a continuum of ligand classes making up the bulk ligand pool, studies to date largely focused on the dominant ligand. Thus, most studies have overlooked the need to assess where these targeted molecules fit across the spectrum of ligands that comprise the bulk ligand pool. Here we summarize present knowledge to critically assess the source(s), function(s), production pathways, and loss mechanisms of three important iron-binding organic ligand groups in order to assess their distinctive characteristics and how they link with observed ligand distributions. We considered that ligands are contained in broad groupings of exopolymer substances (EPS), humic substances (HS), and siderophores; using literature data for speciation modeling suggested that this adequately described the iron speciation reported in the ocean. We hypothesize that a holistic viewpoint of the multi-faceted controls on ligands dynamics is essential to begin to understand why some ligands can be expected to dominate in particular oceanic regions, depth strata, or exhibit seasonality and/or lateral gradients. We advocate that the development of a regional classification will enhance our understanding of the changing composition of the bulk ligand pool across the global ocean and to help address to what extent seasonality influences the makeup of this pool. This classification, based on selected functional ligand classes, can act as a bridge to use future ligand datasets to fill in the gaps in the continuum

Utilization and long‐term persistence of direct oral anticoagulants among patients with nonvalvular atrial fibrillation and liver disease

Aims: We characterized the utilization and long-term treatment persistence of direct oral anticoagulants (DOACs) in patients with nonvalvular atrial fibrillation (NVAF) and liver disease. Method: Using the UK Clinical Practice Research Datalink, we assembled a population-based cohort of NVAF patients with liver disease initiating oral anticoagulants between 2011 and 2020. Logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs) of the association between patient characteristics and initiation of DOACs vs vitamin K antagonists (VKAs). Cox proportional hazards models estimated hazard ratios (HRs) and 95% CIs of the association between patient characteristics and the switch from VKAs to DOACs vs remaining on VKAs. We also assessed the 5-year treatment persistence with DOACs vs VKAs, and whether ischemic stroke or bleeding preceded treatment discontinuation. Results: Our cohort included 3167 NVAF patients with liver disease initiating DOACs (n = 2247, 71%) or VKAs (n = 920, 29%). Initiators of DOACs were more likely to have prior ischemic stroke (OR 1.44, 95% CI 1.12-1.85) than VKA initiators but less likely to have used antiplatelet agents (OR 0.66, 95% CI 0.53-0.82). Patients switching to DOACs were more likely to have used selective serotonin reuptake inhibitors (HR 1.64, 95% CI 1.13-2.37) than those remaining on VKAs. At 5 years, 31% of DOAC initiators and 9% of VKA initiators remained persistent. Only few patients were diagnosed with ischemic stroke or bleeding prior to treatment discontinuation. Conclusion: Most NVAF patients with liver disease initiated treatment with DOACs. Long-term persistence with DOACs was higher than with VKAs but remained relatively low

Reliability and validity of the Brief Illness Perception Questionnaire (B-IPQ) in individuals with a recently acquired spinal cord injury

Objective To assess the reliability and validity of the Brief Illness Perception Questionnaire (B-IPQ) and possible subscales, and to interpret Brief Illness Perception Questionnaire (B-IPQ) total scores, in individuals with a spinal cord injury. Design Cross-sectional Setting Seven Dutch rehabilitation centres Subjects Individuals with a recently acquired traumatic or non-traumatic spinal cord injury at the start of inpatient spinal cord injury rehabilitation (N = 270). Main measure The Brief Illness Perception Questionnaire (B-IPQ) consists of eight items on an individual's cognitive and emotional representation of one's health conditions. Principal component analysis was performed to identify possible Brief Illness Perception Questionnaire (B-IPQ) subscales. Validity was assessed by testing hypotheses on correlations between the Brief Illness Perception Questionnaire (B-IPQ) and other measures. Cut-off points of the Brief Illness Perception Questionnaire (B-IPQ) total score were determined. Results Mean (SD) age of participants was 60.1 (16.5) years, 188 (71%) were male, and 119 (44%) had tetraplegia. Three potential subscales were revealed. Cronbach's alpha was acceptable for only one subscale. This subscale was named 'consequences' and included the items 'consequences', 'symptom burden', 'concern', and 'emotions'. The Brief Illness Perception Questionnaire (B-IPQ) total and the consequence subscale showed the expected strong correlations (>.50) with symptoms of anxiety and depression. Mean (SD) scores were 40.9 (12.3) on the 8-item Brief Illness Perception Questionnaire (B-IPQ) (range 0-80) and 25.1 (8.1) on the consequences subscale (range 0-40). Cut-off points for the Brief Illness Perception Questionnaire (B-IPQ) total score were determined as follows: = 50 indicating high experienced threat. Conclusion The Brief Illness Perception Questionnaire (B-IPQ) total and consequences subscale seem applicable in individuals with a spinal cord injury in the rehabilitation practice and research

Influence of Mature Overstory Trees on Adjacent 12-Year Regeneration and the Woody Understory: Aggregated Retention versus Intact Forest

Retention harvesting, an approach that intentionally retains legacy features such as mature overstory trees, provides options for achieving ecological objectives. At the same time, retained overstory trees may compete with the nearby recovering understory for resources, and much remains to be learned about potential trade-offs with regeneration objectives, particularly over extended time periods. We assessed the influence of aggregated retention (reserved mature overstory and understory patches) versus intact forest on structure and productivity (standing biomass) of the adjacent woody understory and regeneration 12 years after harvest in northern Minnesota, USA. Each site was dominated by Populus tremuloides Michx., a species that regenerates prolifically via root sprouts following disturbance. Overall, fewer differences than expected occurred between the effects of intact forest and aggregated retention on regeneration, despite the small size (0.1 ha) of aggregates. Instead, harvest status and distance from harvest edge had a greater influence on structure and standing woody biomass. Proximity to aggregates reduced large sapling biomass (all species, combined) relative to open conditions, but only up to 5 m into harvested areas. This suggests the trade-off for achieving productivity objectives might be minimal if managers use retention aggregates in this region to achieve ecological objectives and meet management guidelines

High-level feature detection from video in TRECVid: a 5-year retrospective of achievements

Successful and effective content-based access to digital video requires fast, accurate and scalable methods to determine the video content automatically. A variety of contemporary approaches to this rely on text taken from speech within the video, or on matching one video frame against others using low-level characteristics like colour, texture, or shapes, or on determining and matching objects appearing within the video. Possibly the most important technique, however, is one which determines the presence or absence of a high-level or semantic feature, within a video clip or shot. By utilizing dozens, hundreds or even thousands of such semantic features we can support many kinds of content-based video navigation. Critically however, this depends on being able to determine whether each feature is or is not present in a video clip. The last 5 years have seen much progress in the development of techniques to determine the presence of semantic features within video. This progress can be tracked in the annual TRECVid benchmarking activity where dozens of research groups measure the effectiveness of their techniques on common data and using an open, metrics-based approach. In this chapter we summarise the work done on the TRECVid high-level feature task, showing the progress made year-on-year. This provides a fairly comprehensive statement on where the state-of-the-art is regarding this important task, not just for one research group or for one approach, but across the spectrum. We then use this past and on-going work as a basis for highlighting the trends that are emerging in this area, and the questions which remain to be addressed before we can achieve large-scale, fast and reliable high-level feature detection on video

Methodological Reflection on the Co-Construction of Meaning within the South African Domestic Worker Sector: Challenging the Notion of “Voicelessness”

Globally the domestic worker sector is characterised by a sense of “voicelessness”. Given the centrality of participant engagement within the interpretivist paradigm, accessing those with firsthand knowledge of the phenomena under investigation proved challenging. This is attributed to the institutionalised nature of the sector and the initial outsider status of the researchers. This article presents a transparent account of the methodological considerations that guided the co-construction of meaning within this context. Two thousand leaflets were distributed. By describing the intended study, inviting participation and providing assurances of confidentiality an initial rapport was established. Purposive, respondent-driven self-sampling resulted in 20 female participants employed as domestic workers. The pilot study indicated the value of using metaphors while exploring tentative topics. An interview guide facilitated the exploration of key concepts during our engagement. In-depth interviews were transcribed and analysed through an inductive process of data reduction. Rich, dense descriptive verbatim accounts of participants’ lived realities confirmed data saturation. Emerging themes confirmed that the South African domestic worker sector is far from being voiceless if we are willing to listen. Making these voices heard constitutes a vital step in future efforts to empower this neglected sector of the labour market. DOI: 10.5901/mjss.2014.v5n20p72