63 research outputs found
Simple and analytical function for the Stark profile of the Hα line and its application to plasma characterization
The increasing application of plasma based technologies over a wide range of fields has led to the necessity of an optimal determination of the characteristic parameters of the plasma systems. Optical Emission Spectroscopy techniques have been proved as an excellent tool to that end. These techniques are based on the collection and analysis of the radiation coming from the plasma, being classified between molecular and atomic emission. Among atomic emission lines, Hydrogen Balmer series lines are the most measured. The Hβ line is usually the most employed one for plasma diagnosis but under some conditions, the Hβ line is not always detectable and only the Hα line can be detected. For these lines, it is well known that their shapes are the result of the convolution of three profile types: Lorentzians, Gaussians and Starks. But while the first two types present analytical functions, models explaining the Stark profile do not offer these. So, in this paper we propose an accurate analytical function for the Stark profile of the Hα line allowing improving the determination of characteristic parameters of plasma with respect to the methods traditionally used
A simple and accurate analytical model of the Stark profile and its application to plasma characterization
Optical Emission Spectroscopy techniques are among the most employed to perform the characterization of laboratory plasmas. The analysis of the obtained data is based on the convolution of three different types of profiles: Lorentzians, Gaussians and Starks. While analytic expressions are available for the first two types, the Stark profile has been traditionally obtained through theoretical calculations using different models. In this paper, we propose is a simple and accurate analytical function that can be employed as approximation of a Stark profile. The application of this new model may simplify the analysis of plasmas
Bringing farmers back into breeding. Experiences with participatory plant breeding and challenges for institutionalization
Município de Cascavel: atualização cadastral e a sua aplicação ao exercício de planeamento urbanístico
A proximidade da revisão do Plano Diretor 2012 (PD2012) tornou essencial uma reflexão dos últimos anos de planeamento do Município de Cascavel - Brasil, e o estabelecimento de uma estratégia de futuro, que integre o Cadastro Multifinalitário (CdM) e os Sistema de Informações Territoriais, já que têm vindo a ganhar importância no processo de tomada de decisões em diversas áreas da administração municipal no Brasil.
Este estudo, realizado a dois tempos, começou por demonstrar o potencial das imagens de satélite, de grande resolução espacial, no auxílio da tarefa de atualização de bases de dados cadastrais. Por fim, tendo por base a informação cadastral em formato digital analisaram-se três indicadores e respetivos subindicadores - finalidade, pedologia e património - que foram confrontados com o PD2012, em vigor.
Através da compreensão das estratégias de planeamento territorial, suportada pelas ferramentas dos Sistemas de Informação Geográfica, podemos demonstrar que a informação cadastral presente no CdM e a utilização de dados de deteção remota para a produção de cartografia, sustentam as análises temáticas e estatística espacial, podendo apoiar tanto planeadores como decisores, nas suas funções
Protein aggregation and calcium dysregulation are hallmarks of familial Parkinson's disease in midbrain dopaminergic neurons
Mutations in the SNCA gene cause autosomal dominant Parkinson’s disease (PD), with loss of dopaminergic neurons in the substantia nigra, and aggregation of α-synuclein. The sequence of molecular events that proceed from an SNCA mutation during development, to end-stage pathology is unknown. Utilising human-induced pluripotent stem cells (hiPSCs), we resolved the temporal sequence of SNCA-induced pathophysiological events in order to discover early, and likely causative, events. Our small molecule-based protocol generates highly enriched midbrain dopaminergic (mDA) neurons: molecular identity was confirmed using single-cell RNA sequencing and proteomics, and functional identity was established through dopamine synthesis, and measures of electrophysiological activity. At the earliest stage of differentiation, prior to maturation to mDA neurons, we demonstrate the formation of small β-sheet-rich oligomeric aggregates, in SNCA-mutant cultures. Aggregation persists and progresses, ultimately resulting in the accumulation of phosphorylated α-synuclein aggregates. Impaired intracellular calcium signalling, increased basal calcium, and impairments in mitochondrial calcium handling occurred early at day 34–41 post differentiation. Once midbrain identity fully developed, at day 48–62 post differentiation, SNCA-mutant neurons exhibited mitochondrial dysfunction, oxidative stress, lysosomal swelling and increased autophagy. Ultimately these multiple cellular stresses lead to abnormal excitability, altered neuronal activity, and cell death. Our differentiation paradigm generates an efficient model for studying disease mechanisms in PD and highlights that protein misfolding to generate intraneuronal oligomers is one of the earliest critical events driving disease in human neurons, rather than a late-stage hallmark of the disease
The association between family and community social capital and health risk behaviours in young people: an integrative review
Background:
Health risk behaviours known to result in poorer outcomes in adulthood are generally established in late childhood and adolescence. These ‘risky’ behaviours include smoking, alcohol and illicit drug use and sexual risk taking. While the role of social capital in the establishment of health risk behaviours in young people has been explored, to date, no attempt has been made to consolidate the evidence in the form of a review. Thus, this integrative review was undertaken to identify and synthesise research findings on the role and impact of family and community social capital on health risk behaviours in young people and provide a consolidated evidence base to inform multi-sectorial policy and practice.<p></p>
Methods:
Key electronic databases were searched (i.e. ASSIA, CINAHL, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects, Embase, Medline, PsycINFO, Sociological Abstracts) for relevant studies and this was complemented by hand searching. Inclusion/exclusion criteria were applied and data was extracted from the included studies. Heterogeneity in study design and the outcomes assessed precluded meta-analysis/meta-synthesis; the results are therefore presented in narrative form.<p></p>
Results:
Thirty-four papers satisfied the review inclusion criteria; most were cross-sectional surveys. The majority of the studies were conducted in North America (n=25), with three being conducted in the UK. Sample sizes ranged from 61 to 98,340. The synthesised evidence demonstrates that social capital is an important construct for understanding the establishment of health risk behaviours in young people. The different elements of family and community social capital varied in terms of their saliency within each behavioural domain, with positive parent–child relations, parental monitoring, religiosity and school quality being particularly important in reducing risk.<p></p>
Conclusions:
This review is the first to systematically synthesise research findings about the association between social capital and health risk behaviours in young people. While providing evidence that may inform the development of interventions framed around social capital, the review also highlights key areas where further research is required to provide a fuller account of the nature and role of social capital in influencing the uptake of health risk behaviours.<p></p>
Global disparities in surgeons’ workloads, academic engagement and rest periods: the on-calL shIft fOr geNEral SurgeonS (LIONESS) study
: The workload of general surgeons is multifaceted, encompassing not only surgical procedures but also a myriad of other responsibilities. From April to May 2023, we conducted a CHERRIES-compliant internet-based survey analyzing clinical practice, academic engagement, and post-on-call rest. The questionnaire featured six sections with 35 questions. Statistical analysis used Chi-square tests, ANOVA, and logistic regression (SPSS® v. 28). The survey received a total of 1.046 responses (65.4%). Over 78.0% of responders came from Europe, 65.1% came from a general surgery unit; 92.8% of European and 87.5% of North American respondents were involved in research, compared to 71.7% in Africa. Europe led in publishing research studies (6.6 ± 8.6 yearly). Teaching involvement was high in North America (100%) and Africa (91.7%). Surgeons reported an average of 6.7 ± 4.9 on-call shifts per month, with European and North American surgeons experiencing 6.5 ± 4.9 and 7.8 ± 4.1 on-calls monthly, respectively. African surgeons had the highest on-call frequency (8.7 ± 6.1). Post-on-call, only 35.1% of respondents received a day off. Europeans were most likely (40%) to have a day off, while African surgeons were least likely (6.7%). On the adjusted multivariable analysis HDI (Human Development Index) (aOR 1.993) hospital capacity > 400 beds (aOR 2.423), working in a specialty surgery unit (aOR 2.087), and making the on-call in-house (aOR 5.446), significantly predicted the likelihood of having a day off after an on-call shift. Our study revealed critical insights into the disparities in workload, access to research, and professional opportunities for surgeons across different continents, underscored by the HDI
Interparental Violence: Similarities and Discrepancies Between Narratives of Mothers and Their Children
Shapley value-based approaches to explain the quality of predictions by classifiers
The use of algorithm-agnostic approaches for explainable machine learning is an emerging area of research. When explaining the contribution of features towards the predicted outcome, traditionally, the focus remains on explaining the prediction itself, however a little has been done on explaining the quality of prediction of these models, where the quality can be assessed by the algorithm performance when changing the thresholds for classification. In this paper, we propose the use of Shapley values to explain the contribution of features towards the overall algorithm performance, measured in terms of Receiver-operating Characteristics (ROC) curve and the Area under the ROC curve (AUC). With the help of an illustrative example, we demonstrate the proposed idea of explaining the ROC curve, and visualising the uncertainties in these curves. For imbalanced datasets, the use of Precision-Recall Curve (PRC) is considered more appropriate, therefore we also demonstrate how to explain the PRCs with the help of Shapley values. The explanation of the model performance can help analysts in a number of ways, for example, in feature selection by identifying the irrelevant features that can be removed to reduce the computational complexity. It can also help in identifying the features having critical contributions towards the overall algorithm performance
Which factors influence number updating in working memory? The effects of size distance and suppression
Updating information in working memory is a critical process which makes possible to
have available, at every moment, the information most relevant for mind operations.
However, the specific mechanisms underlying the updating process have rarely been
analysed. This paper examines the importance of two of the mechanisms implicated in a
numerical updating task: item comparison and item substitution. The item comparison
mechanism was studied by manipulating the size distance between items. The item
substitution mechanism was investigated by increasing/decreasing the number of
updates within trials. Furthermore, in order to examine the effects of time constraints,
presentation rate was manipulated. Over three experiments, the results obtained
highlighted that updating performance is mainly influenced by suppression request,
even when the presentation rate is self-paced. However, errors depend on the distance
between items. The implications of the results for the understanding of updating are
discussed
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