Confidence in assessing the effectiveness of bath treatments for the control of sea lice on Norwegian salmon farms

The salmon louse Lepeophtheirus salmonis is the most important ectoparasite of farmed salmonids in the Northern hemisphere, having a major economic and ecological impact on the sustainability of this sector of the aquaculture industry. To a large extent, control of L. salmonis relies on the use of topical delousing chemical treatments in the form of baths. Improvements in methods for the administration and assessment of bathtreatments have not kept pace with the rapid modernization and intensification of the salmon industry. Bathtreatments present technical and biological challenges, including best practice methods for the estimation of the effect of licetreatment interventions. In this communication, we compare and contrast methods to calculate and interpret treatmenteffectiveness at pen and site level. The methods are illustrated for the calculation of the percentage reduction in mean abundance of mobile lice with a measure of confidence. Six different methods for the calculation of confidence intervals across different probability levels were compared. We found the quasi-Poisson method with a 90% confidence interval to be informative and robust for the measurement of bathtreatment performance

Composite fermion-boson mapping for fermionic lattice models

We present a mapping of elementary fermion operators onto a quadratic form of composite fermionic and bosonic operators. The mapping is an exact isomorphism as long as the physical constraint of one composite particle per cluster is satisfied. This condition is treated on average in a composite particle mean-field approach, which consists of an ansatz that decouples the composite fermionic and bosonic sectors. The theory is tested on the one- and two-dimensional Hubbard models. Using a Bogoliubov determinant for the composite fermions and either a coherent or Bogoliubov state for the bosons, we obtain a simple and accurate procedure for treating the Mott insulating phase of the Hubbard model with mean-field computational cost

COMPETITIVE CELL-SPECIFIC INTEGRATION AND SURVIVAL OF ADULT-BORN NEURONS IN THE MOUSE OLFACTORY BULB

In several areas of the adult brain, notably the olfactory bulb, new neurons are generated and integrated into existing mature circuits. This observation raises questions about how an ongoing developmental process shapes adult brain circuitry and opens potential treatment avenues for neurological disorders such as traumatic brain injury, ischemia, depression, and degenerative diseases. In the networks where adult neurogenesis occurs, the integration of adult-born neurons is modulated by activity. The experiments in this dissertation are designed to address the hypothesis that adult-born neurons integrate into mature circuits in a competitive, activity-dependent manner. Specifically, we sought to address the question of whether activity in adult-born neurons directly causes enhanced survival of particular active newborn neurons in a cell-autonomous fashion, or whether survival is a competitive process in which the most active cells in the network have the highest chance of survival. To differentiate between these two hypotheses required manipulating activity both of the adult-born neurons and other neurons within the network. Here we used both virus-mediated reduction of cell intrinsic activity and reduced sensory stimuli to show that survival is a competitive process in which the most active cells in the network have the highest chance of survival. RNA-based knockdown of Na+ channels resulted in decreased survival of adult-born neurons from 10-21 d.p.i. We then investigated the role of circuit level activity by inducing sensory deprivation through naris occlusion. Adult-born neurons with normal cell-intrinsic activity showed a reduction in survival in a sensory deprived circuit. But, interestingly, adult-born neurons with reduced intrinsic excitability showed an increased rate of survival in a sensory deprived circuit. These results provide important insights into the role of activity in the integration and therapeutic potential of neural stem cells in mature functional brain circuits

A Ubiquitous Learning Model for Education and Training Processes Supported by TV Everywhere Platforms

Advances in technology and digital convergence, for example Netflix, enable users to view TV and video without time or place restrictions. These advances can be applied in education and training processes to enable ubiquitous learning (u-learning). However, a literature review (of the years 2002 to 2018) on u-learning models yielded scarce information about its implementation, specifically demonstrating a lack of application alternatives that could provide access to TV regardless of place and device. To contribute to this and other challenges in education, the objective of this study is to propose a reference model for u-learning implementation involving cloud-supported TV/video platforms. The model was validated in a university context by a group of experts and applied through a prototype in a real setting with students, and it showed favourable results and improvement in student performance

Morphological Analysis of Activity-Reduced Adult-Born Neurons in the Mouse Olfactory Bulb

Adult-born neurons (ABNs) are added to the olfactory bulb (OB) throughout life in rodents. While many factors have been identified as regulating the survival and integration of ABNs into existing circuitry, the understanding of how these factors affect ABN morphology and connectivity is limited. Here we compare how cell intrinsic [small interfering RNA (siRNA) knock-down of voltage gated sodium channels NaV1.1–1.3] and circuit level (naris occlusion) reductions in activity affect ABN morphology during integration into the OB. We found that both manipulations reduce the number of dendritic spines (and thus likely the number of reciprocal synaptic connections) formed with the surrounding circuitry and inhibited dendritic ramification of ABNs. Further, we identified regions of ABN apical dendrites where the largest and most significant decreases occur following siRNA knock-down or naris occlusion. In siRNA knock-down cells, reduction of spines is observed in proximal regions of the apical dendrite. This suggests that distal regions of the dendrite may remain active independent of NaV1.1–1.3 channel expression, perhaps facilitated by activation of T-type calcium channels and NMDA receptors. By contrast, circuit level reduction of activity by naris occlusion resulted in a global depression of spine number. Together, these results indicate that ABNs retain the ability to develop their typical overall morphological features regardless of experienced activity, and activity modulates the number and location of formed connections

Multivariate evaluation of the effectiveness of treatment efficacy of cypermethrin against sea lice (Lepeophtheirus salmonis) in Atlantic salmon (Salmo salar)

Background: The sea louse Lepeophtheirus salmonis is the most important ectoparasite of farmed Atlantic salmon (Salmo salar) in Norwegian aquaculture. Control of sea lice is primarily dependent on the use of delousing chemotherapeutants, which are both expensive and toxic to other wildlife. The method most commonly used for monitoring treatment effectiveness relies on measuring the percentage reduction in the mobile stages of Lepeophtheirus salmonis only. However, this does not account for changes in the other sea lice stages and may result in misleading or incomplete interpretation regarding the effectiveness of treatment. With the aim of improving the evaluation of delousing treatments, we explored multivariate analyses of bath treatments using the topical pyrethroid, cypermethrin, in salmon pens at five Norwegian production sites.Results: Conventional univariate analysis indicated reductions of over 90% in mobile stages at all sites. In contrast, multivariate analyses indicated differing treatment effectiveness between sites (p-value < 0.01) based on changes in the proportion and abundance of the chalimus and PAAM (pre-adult and adult males) stages. Low water temperatures and shortened intervals between sampling after treatment may account for the differences in the composition of chalimus and PAAM stage groups following treatment. Using multivariate analysis, such factors could be separated from those which were attributable to inadequate treatment or chemotherapeutant failure.Conclusions: Multivariate analyses for evaluation of treatment effectiveness against multiple life cycle stages of L. salmonis yield additional information beyond that derivable from univariate methods. This can aid in the identification of causes of apparent treatment failure in salmon aquaculture

Tuning the endocytosis mechanism of Zr-based metal−organic frameworks through linker functionalization

A critical bottleneck for the use of metal-organic frameworks (MOFs) as drug delivery systems has been allowing them to reach their intracellular targets without being degraded in the acidic environment of the lysosomes. Cells take up particles by endocytosis through multiple biochemical pathways, and the fate of these particles depends on these routes of entry. Here, we show the effect of functional group incorporation into a series of Zr-based MOFs on their endocytosis mechanisms, allowing us to design an effi-cient drug delivery system. In particular, naphthalene-2,6-dicarboxylic acid and 4,4'-biphenyldicarboxylic acid ligands promote entry through the caveolin-pathway, allowing the particles to avoid lysosomal degradation and be delivered into the cytosol, en-hancing their therapeutic activity when loaded with drugs