Side-emitting fibers: targeted light scattering in optical fibers

Light scattering in optical fibers can transform the fiber into a linear light source with customizable emission properties: a side-emitting fiber. Side-emitting fibers are light sources with special angular and longitudinal emission characteristics, not generally encountered in other light sources: they emit radiation in all directions like a diffuse light source, but the emission is preferentially directed forward. Also, the fiber’s surface emission may decrease exponentially or vary along the fiber. The contribution of this dissertation to the literature on side-emitting fibers is twofold; first, it will show how these fiber emission parameters will influence the generated light field in the proximity and the far field. Second, it will show how to customize the emission properties by using femtosecond laser-generated scattering centers: Arranging these building blocks can generate customized longitudinal emission profiles. Furthermore, it will derive an electromagnetic model of the scattering behavior of these modifications to show how their stochastic properties, shape, and volume affect the angular emission profile and their scattering power

“A whole new language and a new world”: Seconded Teachers’ Experiences in a Faculty of Education

It is common practice in university faculties of education to second teachers for limited periods. However, few recent studies have examined how secondees perceive themselves in this role, particularly in relation to the increased demands to assume research as well as teaching duties. Three seconded school personnel were interviewed to explore their experiences of secondment in a faculty of education in Canada. One had previously been a teacher, one an educational consultant, and the third a principal. Qualitative data analysis revealed (a) the differences between schools and faculty; (b) the benefits of secondment for secondees and the institution; (c) secondees’ identity as teachers; (d) secondees’ mixed feelings about research; and finally (e) the drawbacks and issues in being seconded. Recommendations for future secondments and research directions conclude the article.Dans les facultés d'éducation à l'université, le détachement de personnel pour une période limitée constitue une pratique courante. Quelques études récentes portent sur la perception qu'ont les employés détachés de leur rôle, notamment en fonction de la hausse de demandes exigeant qu'ils accomplissent des tâches liées à la recherche en plus de celles relatives à l'enseignement. Nous avons interviewé trois membres du personnel scolaire détaché par rapport à leurs expériences de détachement dans une faculté de formation des enseignants au Canada. Parmi ces membres, il avait un ancien enseignant, un conseiller pédagogique et un directeur d'école. Une analyse qualitative des données a révélé: (a) les différences entre les écoles et le personnel; (b) les avantages du détachement pour les employés détachés et les institutions; (c) l'identité d'enseignant des employés détachés; (d) les sentiments ambivalents des employés détachés par rapport à la recherche; et finalement (e) les inconvénients et les enjeux liés au détachement. L'article conclut en présentant des recommandations qui visent les détachements et les orientations en recherche à l'avenir

“There’s No Big Book on How to Care”: Primary Pre-Service Teachers’ Experiences of Caring

This study investigated primary, pre-service teachers\u27 experiences regarding their caring role, and the barriers they face when caring for students. Thirteen Australian primary pre-service teachers were individually interviewed. Within a qualitative framework, transcripts were thematically analysed, alongside member checks. While results indicated highly individualised notions of care, common themes included difficulties in navigating the caring teacher role, the caring student-teacher relationship and gaps in training around notions of care. A continuum of care was identified, mediated by student and teacher factors as well as school location. This continuum provides a framework within which pre-service teachers might explore boundary issues

‘We Were All Green and Brand New’: Mentoring in Theories of Child Development for Australian Early Career Preschool Teachers

Three Australian Government commissioned reports from 2011-2017 convey a longstanding child development theory-practice gap in early childhood education. This study explores what informs mentors’ discussions of theories of child development with early career preschool teachers. Grounded in Interpretative Phenomenological Analysis, themes relate to the wide role of the early childhood teacher, variation in initial teacher education, developing teacher identity, emotional connections, and consolidation and extension of university learning of child development theories. Critical discussion of themes from a Freirean perspective illustrates how mentors conveyed experiences of oppression, marginalisation, and liberation. We offer that though the child development theory-practice gap is historically presented as problematic, those interviewed suggest it is a natural and necessary part of the journey for beginning teachers. Although implications for Australian initial teacher education policy and practice are presented, this study serves as a case example for future comparative international research in this field

Angular scattering pattern of femtosecond laser‐induced refractive index modifications in optical fibers

Abstract Focused femtosecond laser irradiation is used to induce light scattering modifications in the core of an optical fiber. This turns the fiber into a diffuse, line‐shaped light source. The scattering is investigated by imaging almost the full solid angle far‐field pattern for the first time. Additionally, an electromagnetic scattering model is developed to explain the observations. The findings herein change how the relationship between light scattering and the refractive index fluctuations is perceived by showing that the far‐field scattering pattern is the power spectral density of the polarization current inside the scattering center. Further, the authors contribute to a better estimation of the scattering process by showing that the total scattering power scales quadratically with the laser‐induced refractive index change and its volume

Development of genomic resources for Rhodes grass (Chloris gayana), draft genome and annotated variant discovery

Genomic resources for grasses, especially warm-season grasses are limited despite their commercial and environmental importance. Here, we report the first annotated draft whole genome sequence for diploid Rhodes grass (Chloris gayana), a tropical C4 species. Generated using long read nanopore sequencing and assembled using the Flye software package, the assembled genome is 603 Mbp in size and comprises 5,233 fragments that were annotated using the GenSas pipeline. The annotated genome has 46,087 predicted genes corresponding to 92.0% of the expected genomic content present via BUSCO analysis. Gene ontology terms and repetitive elements are identified and discussed. An additional 94 individual plant genotypes originating from three diploid and two tetraploid Rhodes grass cultivars were short-read whole genome resequenced (WGR) to generate a single nucleotide polymorphism (SNP) resource for the species that can be used to elucidate inter- and intra-cultivar relationships across both ploidy levels. A total of 75,777 high quality SNPs were used to generate a phylogenetic tree, highlighting the diversity present within the cultivars which agreed with the known breeding history. Differentiation was observed between diploid and tetraploid cultivars. The WGR data were also used to provide insights into the nature and evolution of the tetraploid status of the species, with results largely agreeing with the published literature that the tetraploids are autotetraploid

Calcium-tin alloys as anodes for rechargeable non-aqueous calcium-ion batteries at room temperature

Rechargeable calcium batteries possess attractive features for sustainable energy-storage solutions owing to their high theoretical energy densities, safety aspects and abundant natural resources. However, divalent Ca-ions and reactive Ca metal strongly interact with cathode materials and non-aqueous electrolyte solutions, leading to high charge-transfer barriers at the electrode-electrolyte interface and consequently low electrochemical performance. Here, we demonstrate the feasibility and elucidate the electrochemical properties of calcium-tin (Ca–Sn) alloy anodes for Ca-ion chemistries. Crystallographic and microstructural characterizations reveal that Sn formed from electrochemically dealloying the Ca–Sn alloy possesses unique properties, and that this in-situ formed Sn undergoes subsequent reversible calciation/decalciation as CaSn(3). As demonstration of the suitability of Ca–Sn alloys as anodes for Ca-ion batteries, we assemble coin cells with an organic cathode (1,4-polyanthraquinone) in an electrolyte of 0.25 M calcium tetrakis(hexafluoroisopropyloxy)borate in dimethoxyethane. These electrochemical cells are charged/discharged for 5000 cycles at 260 mA g(−1), retaining a capacity of 78 mAh g(−1) with respect to the organic cathode. The discovery of new class of Ca–Sn alloy anodes opens a promising avenue towards viable high-performance Ca-ion batteries

Needs, expectations and consequences for the child growing up in a family with a parent with mental illness

Parental mental illness is considered one of the strongest risk-factors for development of offspring psychopathology. The lack of pan-European guidelines for empowering children of parents with mental illness led to EU project CAMILLE - Empowerment of Children and Adolescents of Mentally Ill Parents through Training of Professionals working with children and adolescents. The first task in this project, was to analyse needs, expectations and consequences for children, with respect to living with a parent with mental illness. The aim this paper is to report results of these analyses. The qualitative research was conducted in England, Finland, Germany, Italy, Norway, Poland and Scotland (N=96). There were 3 types of focus groups: (1) professionals (doctors, nurses, psychologists, social workers), (2) adult children and partners of a person with mental illness, (3) parents who have experienced mental illness during their parenthood. Framework analysis method was used. Results of the study highlighted that the main consequences for children of parental mental illness were role reversal, emotional and behavioural problems, lack of parent’s attention and stigma. The main needs of these children were emotional support, security and multidisciplinary help. Implications for practice are: (1) professionals working with parents with mental illness should be aware of the specific consequences for the children; (2) to empower children they should focus on them, but not excluding parents from the parental roles; (3) the multi-agency collaboration is necessary; (4) schools should provide counselling and teach staff and students about mental health problems to reduce stigm

Establishing a Stable Anode–Electrolyte Interface in Mg Batteries by Electrolyte Additive

Simple magnesium salts with high electrochemical and chemical stability and adequate ionic conductivity represent a new-generation electrolyte for magnesium (Mg) batteries. Similar to other Mg electrolytes, the simple-salt electrolyte also suffers from high charge-transfer resistance on the Mg surface due to the adsorbed species in the solution. In the current study, we built a model Mg cell system with the Mg[B(hfip)4]2/DME electrolyte and Chevrel phase Mo6S8 cathode, to demonstrate the effect of such anode–electrolyte interfacial properties on the full-cell performance. It was found that the cell required additional activation cycles to achieve its maximal capacity. The activation process is mainly attributed to the conditioning of the anode–electrolyte interface, which could be boosted by introducing an additive amount of Mg(BH4)2 to the Mg[B(hfip)4]2/DME electrolyte. Electrochemical and spectroscopic analyses revealed that the Mg(BH4)2 additive helps to remove the native oxide layer and promotes the formation of a solid electrolyte interphase layer on Mg. As a result, the full cell with the additive-containing electrolyte delivered a stable capacity from the second cycle onward. Further battery tests showed a reversible cycling for 600 cycles and an excellent rate capability, indicating good compatibility of the Mg(BH4)2 additive. The current study not only provides fundamental insights into the interfacial phenomena in Mg batteries but also highlights the facile tunability of the simple-salt Mg electrolytes