Survey of VLF electric fields in the magnetosphere with the polar orbiting spacecraft, 1964-45a

Very low frequency electric fields in magnetosphere sampled by polar orbiting satellit

Diamond thin film temperature and heat-flux sensors

Diamond film temperature and heat-flux sensors are developed using a technology compatible with silicon integrated circuit processing. The technology involves diamond nucleation, patterning, doping, and metallization. Multi-sensor test chips were designed and fabricated to study the thermistor behavior. The minimum feature size (device width) for 1st and 2nd generation chips are 160 and 5 micron, respectively. The p-type diamond thermistors on the 1st generation test chip show temperature and response time ranges of 80-1270 K and 0.29-25 microseconds, respectively. An array of diamond thermistors, acting as heat flux sensors, was successfully fabricated on an oxidized Si rod with a diameter of 1 cm. Some problems were encountered in the patterning of the Pt/Ti ohmic contacts on the rod, due mainly to the surface roughness of the diamond film. The use of thermistors with a minimum width of 5 micron (to improve the spatial resolution of measurement) resulted in lithographic problems related to surface roughness of diamond films. We improved the mean surface roughness from 124 nm to 30 nm by using an ultra high nucleation density of 10(exp 11)/sq cm. To deposit thermistors with such small dimensions on a curved surface, a new 3-D diamond patterning technique is currently under development. This involves writing a diamond seed pattern directly on the curved surface by a computer-controlled nozzle

Evolution of Koch's postulates: towards a twenty-first century understanding of microbial infection

This editorial discusses strengths and limitations of Koch's postulates reviews modifications that have been used over time, and provides a brief introductory comment to the four papers that comprise the themed section herein

Bacterial Communities in Women with Bacterial Vaginosis: High Resolution Phylogenetic Analyses Reveal Relationships of Microbiota to Clinical Criteria

Bacterial vaginosis (BV) is a common condition that is associated with numerous adverse health outcomes and is characterized by poorly understood changes in the vaginal microbiota. We sought to describe the composition and diversity of the vaginal bacterial biota in women with BV using deep sequencing of the 16S rRNA gene coupled with species-level taxonomic identification. We investigated the associations between the presence of individual bacterial species and clinical diagnostic characteristics of BV.Broad-range 16S rRNA gene PCR and pyrosequencing were performed on vaginal swabs from 220 women with and without BV. BV was assessed by Amsel's clinical criteria and confirmed by Gram stain. Taxonomic classification was performed using phylogenetic placement tools that assigned 99% of query sequence reads to the species level. Women with BV had heterogeneous vaginal bacterial communities that were usually not dominated by a single taxon. In the absence of BV, vaginal bacterial communities were dominated by either Lactobacillus crispatus or Lactobacillus iners. Leptotrichia amnionii and Eggerthella sp. were the only two BV-associated bacteria (BVABs) significantly associated with each of the four Amsel's criteria. Co-occurrence analysis revealed the presence of several sub-groups of BVABs suggesting metabolic co-dependencies. Greater abundance of several BVABs was observed in Black women without BV.The human vaginal bacterial biota is heterogeneous and marked by greater species richness and diversity in women with BV; no species is universally present. Different bacterial species have different associations with the four clinical criteria, which may account for discrepancies often observed between Amsel and Nugent (Gram stain) diagnostic criteria. Several BVABs exhibited race-dependent prevalence when analyzed in separate groups by BV status which may contribute to increased incidence of BV in Black women. Tools developed in this project can be used to study microbial ecology in diverse settings at high resolution

A Model of Turbulence in Magnetized Plasmas: Implications for the Dissipation Range in the Solar Wind

This paper studies the turbulent cascade of magnetic energy in weakly collisional magnetized plasmas. A cascade model is presented, based on the assumptions of local nonlinear energy transfer in wavenumber space, critical balance between linear propagation and nonlinear interaction times, and the applicability of linear dissipation rates for the nonlinearly turbulent plasma. The model follows the nonlinear cascade of energy from the driving scale in the MHD regime, through the transition at the ion Larmor radius into the kinetic Alfven wave regime, in which the turbulence is dissipated by kinetic processes. The turbulent fluctuations remain at frequencies below the ion cyclotron frequency due to the strong anisotropy of the turbulent fluctuations, k_parallel << k_perp (implied by critical balance). In this limit, the turbulence is optimally described by gyrokinetics; it is shown that the gyrokinetic approximation is well satisfied for typical slow solar wind parameters. Wave phase velocity measurements are consistent with a kinetic Alfven wave cascade and not the onset of ion cyclotron damping. The conditions under which the gyrokinetic cascade reaches the ion cyclotron frequency are established. Cascade model solutions imply that collisionless damping provides a natural explanation for the observed range of spectral indices in the dissipation range of the solar wind. The dissipation range spectrum is predicted to be an exponential fall off; the power-law behavior apparent in observations may be an artifact of limited instrumental sensitivity. The cascade model is motivated by a programme of gyrokinetic simulations of turbulence and particle heating in the solar wind.Comment: 29 pages, 14 figure

Practices and motives behind antibiotics provision in drug outlets in Tanzania : a qualitative study

Funding: This study was part of the larger 3-country Holistic Approach to Unravel Antibacterial Resistance in East Africa (HATUA) project funded by the National Institute for Health Research, Medical Research Council and the Department of Health and Social Care, Award (MR/S004785/1).Dispensing antibiotics without prescription is among the major factors leading to antimicrobial resistance. Dispensing of antibiotics without prescription has negative impact at the individual and societal level leading to poor patient outcomes, and increased risks of resistant bacteria facilitated by inappropriate choice of antibiotics doses/courses. Antimicrobial resistance is a global public health threat which is projected to cause 10 million deaths by 2050 if no significant actions are taken to address this problem This study explored the practices and motives behind dispensing of antibiotics without prescription among community drug outlets in Tanzania. Finding of this study provides more strategies to antibiotics stewardship intervention. In-depth interviews with 28 drug dispensers were conducted for three months consecutively between November 2019 and January 2020 in 12 community pharmacies and 16 Accredited Drug Dispensing Outlets (ADDOs) in the Mwanza, Kilimanjaro and Mbeya regions of Tanzania. Transcripts were coded and analyzed thematically using NVivo12 software. Majority of dispensers admitted to providing antibiotics without prescriptions, selling incomplete courses of antibiotics and not giving detailed instructions to customers on how to use the drugs. These practices were motivated by several factors including customers’ pressure/customers’ demands, business orientation-financial gain of drug dispensers, and low purchasing power of patients/customers. It is important to address the motives behind the unauthorized dispensing antibiotics. On top of the existing regulation and enforcement, we recommend the government to empower customers with education and purchasing power of drugs which can enhance the dispensers adherence to the dispensing regulations. Furthermore, we recommend ethnographic research to inform antibiotic stewardship interventions going beyond awareness raising, education and advocacy campaigns. This will address structural drivers of AMR such as poverty and inadequate government health services, and the disconnect between public messaging and/or policy and the public itself.Publisher PDFPeer reviewe

Estimating Level of Engagement from Ocular Landmarks

E-learning offers many advantages like being economical, flexible and customizable, but also has challenging aspects such as lack of – social-interaction, which results in contemplation and sense of remoteness. To overcome these and sustain learners’ motivation, various stimuli can be incorporated. Nevertheless, such adjustments initially require an assessment of engagement level. In this respect, we propose estimating engagement level from facial landmarks exploiting the facts that (i) perceptual decoupling is promoted by blinking during mentally demanding tasks; (ii) eye strain increases blinking rate, which also scales with task disengagement; (iii) eye aspect ratio is in close connection with attentional state and (iv) users’ head position is correlated with their level of involvement. Building empirical models of these actions, we devise a probabilistic estimation framework. Our results indicate that high and low levels of engagement are identified with considerable accuracy, whereas medium levels are inherently more challenging, which is also confirmed by inter-rater agreement of expert coders

An exploratory case study of Olympiad students’ attitudes towards and passion for science

Much is known about high school students’ attitudes towards science but there is almost no research on what passion for science might look like and how it might be manifested. This exploratory case study took advantage of a unique group of highly gifted science students participating in the Australian Science Olympiad (n=69) to explore their attitudes towards school science and science as presented in the Olympiad summer camp. In particular the role the summer camp might play in igniting the students’ passion for science was a focus of the research. Data were collected through a two tiered survey of students’ attitudes towards school science, an evaluative survey of the Olympiad summer camp and in-depth interviews with six participants. Findings indicated that Olympiad students generally had positive attitudes towards school science with most selecting science as one of their favourite subjects. However, an underlying ambivalence about school science was noted in the data. In contrast, the Olympiad summer camp transformed students’ positive attitudes into passion for science. Seven themes emerged from the data providing a foundation for a model of what academic passion for science looks like

Distance travelled : Outcomes and evidence in flexible learning options

Flexible learning options (FLOs) provide individualised learning pathways for disengaged young people with strong emphasis on inclusivity and wellbeing support. Amidst a rapid expansion of Australia’s flexible learning sector, service providers are under increasing pressure to substantiate participant outcomes. This paper stems from a national study of the value of FLOs to young people and the broader Australian community. The study enumerates the outcomes valued by flexible learning practitioners, as well as the various evidence forms they cite to substantiate participant outcomes. Framing success as ‘distance travelled’ (i.e. an individual’s progress relative to his or her own starting point), practitioners demonstrate critical awareness of the social and structural mechanisms by which young people are marginalised from mainstream schooling. Holistic assessment practices also reveal practitioners’ efforts to expand the terms of reference by which educational outcomes may be validated in alternative education settings