54 research outputs found
A longitudinal study on the development of the professional identity of future physics teachers
This presentation derives from a Masterâs thesis that aimed to understand some aspects of the conceptions of undergraduates in Physics on topics such as scientific knowledge, science teaching, and the process of constitution of knowledge for teaching. This study is longitudinal; data were taken from admission to completion of the course and looks for understanding the influence of the pedagogical project and the structuring of the course in the formative profile of future Physics teachers.
To assist in the investigative process, the following question was established: How do the conceptions of future Physics teachers regarding scientific knowledge, science teaching, and the process of constitution of knowledge for teaching change throughout the course and outline their professional identity?
The production context of this study took place in the Physics teacher training course at a Brazilian public university. The constitution of the research data occurred through questionnaires answered by the undergraduates annually, from university admission until the completion of the course. In addition, semi structured interviews were also carried out at the end of graduation.
The theoretical and methodological references that supported the development of this research were the Pecheutian Discourse Analysis (Orlandi, 2015; PĂȘcheux, 2002) and the references in the area of teacher education (Freire, 2020; Goodnough, 2010; McIntyre, 2005; among others).
From the analysis of the interviews and questionnaires, it was possible to understand that the pedagogical project of the course and the curricular structure have an important role in the changes in the conceptions of future Physics teachers and in the construction of their teaching identity.
In addition, it was identified that the teachers' conceptions about the teaching profession are inserted in the perspective of the reflective teacher, which corroborates the constitution of a professional teaching identity in the perspective of the naturalization of an instrumental model of reflective practice, making it impossible for the teacher to reflect critically about the world.
REFERENCES
Freire, P. (2020). Pedagogia da autonomia: saberes necessĂĄrios Ă prĂĄtica educativa (63th ed.). SĂŁo Paulo: Paz e Terra.
Goodnough, K. (2010). Teacher Learning and Collaborative Action Research: Generating a ââKnowledge-of-Practiceââ in the Context of Science Education. Journal of Science Teacher Education, 21, 916-935.
McIntyre, D. (2005). Bridging the gap between research and practice. Cambridge Journal of Education, 35(3), 357-382.
Orlandi, E. P. (2015). AnĂĄlise de Discurso: PrincĂpios & Procedimentos (12th ed.). Campinas: Pontes.
PĂȘcheux, M. (2002). O discurso: estrutura ou acontecimento (3th ed.). Campinas: Pontes
Remineralization strategies in oral hygiene: a position paper of Italian Society of Oral Hygiene Sciences-S.I.S.I.O. working group
Background/Objective:
The clinical conditions that lead to an alteration of the enamel structure are numerous. The diet high in sugars and acidifying
substances, psychological stress that triggers parafunctional behaviors, the reduced intake of fiber-rich foods or alkalizing substances,
together with other factors, contribute to demineralization of the tooth enamel. Dental mineralizing products on the current market
are distinguished according to the dosage form, the active ingredient, the release technology, clinical indications and patient choice.
Currently, it is necessary to propose to oral health professionals a guide to orient themselves in this chaotic choice, in order to prefer
the most effective product for their own clinical target.
Methods:
Italian Society of Oral Hygiene Sciences-S.I.S.I.O. is one of the leading scientific Italian societies representing those dental
hygienists working with high-quality standards and in agreement with scientific evidence: in the last year, the SISIO working group
has carried out a study focused on remineralizing agents in dentistry, in order to give an authoritative point of view to indicate a
guideline in the decision process of the choice of a remineralizing agent. We will report the results pointed out from the last
consensus meeting in 2017.
Results:
We have reported the good the bad and the ugly have been discussed in a critical discussion of such topic.
Conclusion:
The SISIO experience has been reported in this position paper with the aim to serve as a useful aid in the daily choice of the clinical
steps to perform, when dental professionals need to treat demineralized teeth.
Keywords: Dental Hygiene, Oral health, Dental Remineralizing, Enamel, Toothpaste, Mouthwash
Twenty-three unsolved problems in hydrology (UPH) â a community perspective
This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focussed on process-based understanding of hydrological variability and causality at all space and time scales.
Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come
Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study
Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28â2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65â3·22], p\textless0·0001), American Society of Anesthesiologists grades 3â5 versus grades 1â2 (2·35 [1·57â3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01â2·39], p=0·046), emergency versus elective surgery (1·67 [1·06â2·63], p=0·026), and major versus minor surgery (1·52 [1·01â2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research
Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world
Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic.
Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality.
Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States.
Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis.
Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and lowâmiddle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of âsingle-useâ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for lowâmiddle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both highâ and lowâmiddleâincome countries
Avaliação de potenciais biomarcadores de efeito precoces na exposição ocupacional Ă sĂlica cristalina
Garimpeiros de ametistas estĂŁo ocupacionalmente expostos Ă sĂlica cristalina, um agente quĂmico que, ao ser inalado, provoca dano oxidativo e reação inflamatĂłria nos pulmĂ”es, resultando em silicose. Neste sentido, este estudo objetivou avaliar componentes perifĂ©ricos envolvidos na resposta inflamatĂłria e no estresse oxidativo como potenciais biomarcadores de efeito precoces na toxicidade da sĂlica cristalina nestes trabalhadores. Para esta avaliação foram recrutados 30 indivĂduos nĂŁo expostos ocupacionalmente Ă sĂlica cristalina, 38 trabalhadores sem silicose expostos em garimpos e 24 indivĂduos aposentados por silicose. O grupo de expostos foi dividido conforme o tempo de exposição, sendo 19 indivĂduos com 1 a 15 anos de exposição e 19 trabalhadores com mais de 16 anos de exposição. Os biomarcadores inflamatĂłrios avaliados foram a expressĂŁo proteica de L-selectina, ÎČ-2 integrina e molĂ©cula de adesĂŁo intercelular 1 (ICAM-1) na superfĂcie de monĂłcitos e linfĂłcitos, nĂveis sĂ©ricos de C3, C4, proteĂna C reativa ultrassensĂvel (PCRus) e atividade sĂ©rica da enzima adenosina deaminase (ADA). Os biomarcadores de estresse oxidativo avaliados foram malondialdeĂdo (MDA) plasmĂĄtico e vitamina C sĂ©rica. TambĂ©m foram avaliados parĂąmetros bioquĂmicos e hematolĂłgicos. A expressĂŁo de L-selectina na superfĂcie de linfĂłcitos foi significativamente menor nos indivĂduos com mais de 16 anos de exposição comparados aos nĂŁo-expostos (p<0.05), indicando que este Ă© um potencial biomarcador precoce para silicose. Os nĂveis de MDA foram significativamente aumentados nos expostos e nos silicĂłticos comparados aos nĂŁo expostos (p<0.05), enquanto os nĂveis de vitamina C estavam diminuĂdos nos silicĂłticos comparados aos nĂŁo expostos (p<0.05). C3, PCRus, ADA e AST tiveram nĂveis significativamente elevados nos silicĂłticos comparados aos nĂŁo expostos (p<0.05). Glicose e ureia estavam aumentadas em todos os grupos em comparação aos nĂŁo expostos (p<0.05). CorrelaçÔes parciais significativas foram observadas entre os parĂąmetros inflamatĂłrios e de estresse oxidativo, e a L-selectina correlacionou-se negativamente com o tempo de exposição (p<0.001), reforçando a importĂąncia deste componente como potencial biomarcador precoce para ocorrĂȘncia de silicose.Workers of mining activities are exposed to crystalline silica, an agent that leads to pulmonary inflammatory reaction and oxidative damage, resulting in silicosis. Therefore, this work aimed to evaluate inflammatory and oxidative stress parameters as potential early biomarkers of effect to assess crystalline silica toxicity in these workers. For this, 38 crystalline silica exposed workers without silicosis, 24 silicotic individuals and 30 non-occupationally exposed workers were enrolled. Exposed workers were according to the time of exposure: 19 workers with 1-15 years of occupational exposure and 19 workers above 16 years of occupational exposure. The inflammatory parameters assessed were L-selectin, ÎČ-2 integrin and intercellular adhesion molecule-1 (ICAM-1) surface protein expression in lymphocytes and monocytes, C3, C4, high sensitivity-C reactive protein (hs-CRP) and adenosine deaminase (ADA) in serum. As biomarkers of oxidative stress, plasma levels of malondyaldehyde (MDA) and serum levels of vitamin C were determined. Biochemical and hematological parameters were also evaluated. L-selectin surface protein expression was significantly decreased in workers above 16 years of exposure compared to non-exposed individuals (p<0.05). MDA levels were significantly increased in both exposed workers and silicotic groups compared to non-exposed (p<0.05), while vitamin C levels were decreased in silicotic individuals compared to non-exposed (p<0.05). C3, hs-CRP, ADA and aspartate aminotransferase (AST) levels were increased in siliotic individuals compared to non-exposed group (p<0.05). Glucose and urea levels were significantly higher in exposed and silicotic groups compared to NEW group (p<0.05). Significant partial correlations were observed among inflammatory and oxidative stress parameters, and L-selectin was negatively correlated with time of exposure, supporting the relevance of this potential biomarker evaluation in long time exposure to crystalline silica in miners chronically exposed
Three-dimensional scour due to circular jet in cohesive soil
[ITA] Numerose strutture idrauliche, quali scaricatori di piena, dighe e soglie in genere, danno luogo a getti dâacqua con elevato potenziale erosivo nei confronti del terreno sottostante. La progettazione di tali strutture richiede ai progettisti una stima quanto piĂč possibile accurata delle caratteristiche geometriche dello scavo che si potrĂ originare a valle, onde scongiurare danni alle fondazioni. La maggior parte degli studi inerenti ai fenomeni erosivi a valle di getti dâacqua riguarda terreni granulari quali sabbia e ghiaia, il cui comportamento Ăš determinato unicamente da forze inerziali. Al contrario, i terreni coesivi sono caratterizzati da forze attrattive interne che contribuiscono a determinarne il comportamento meccanico e la resistenza allâerosione. Tali forze dipendono da molteplici fattori e sono la causa principale delle diverse modalitĂ erosive che caratterizzano i terreni coesivi. A causa dellâinerente complessitĂ del problema, i terreni coesivi hanno ricevuto minore attenzione dalla comunitĂ scientifica. Lâobiettivo di questa tesi Ăš analizzare il processo di scavo che si produce a valle di un getto dâacqua che impatta su un suolo coesivo. A questo scopo, sono stati condotti test sperimentali con lâutilizzo di un getto a sezione circolare posto a diversi angoli di inclinazione rispetto allâorizzontale (45°, 60°, 75° e 90°), e di unâargilla da manifattura costituente il materiale del fondo mobile. Oggetto principale dellâanalisi sono stati i meccanismi e le morfologie di scavo, ivi compresa la loro evoluzione temporale. I risultati sperimentali hanno permesso di derivare equazioni empiriche per la stima delle principali caratteristiche geometriche della buca di scavo e della loro evoluzione nel tempo. Il presente lavoro contribuisce a chiarire gli aspetti fenomenologici inerenti lo scavo in terreni coesivi e la sua evoluzione temporale, nonchĂ© lâeffetto dellâinclinazione del getto sulle caratteristiche del processo erosivo.
[ENG] Assessing the erosive potentiality of turbulent jets is essential for a safe design of hydraulic structures such as dam spillways, culverts, and grade-control structures. While most studies on jet scour deal with cohesionless soils such as sand and gravel, the erosion of cohesive sediment has received less attention. Nevertheless, cohesive soils are omnipresent in fluvial environments, as riverbeds are usually characterized by a mixture of sand, clay, and silt. Consequently, to avoid structural damages of hydraulic structures and ensure their functionality, the erosional characteristics of cohesive soils must be carefully assessed. Cohesive soils are characterized by interparticle and interaggregate forces which significantly contribute to their resistance to erosion. Such forces depend on a wide number of parameters and are the main cause of the different modes of erosion exhibited by cohesive materials. This thesis aims at advancing current knowledge on scour due to a circular jet in cohesive soil. To this end, a series of experiments were conducted, involving a circular jet impinging on a bed made of pottery clay, at different inclinations with respect to the horizontal (45°, 60°, 75°, and 90°). Observed erosion mechanisms and scour hole morphologies are analyzed, including their evolution. Empirical equations are proposed to estimate the main geometrical features of scour hole at equilibrium and their time evolution. In so doing, this thesis offers further insights on the different modes of erosion of cohesive soils, on the peculiar temporal evolution of scour hole, and on the effect of the impinging angle on scour features
Experimental and theoretical analysis of jet induced scour depth under unsteady flow conditions
In this thesis we address the problem of scour hole caused by a jet plunging into a water pool, laying on a bottom of granular cohesionless material. This is a crucial problem, as scour phenomena occur in many engineering applications. Researchers have widely explored this topic by adopting empirical or semi-theoretical approaches. Although these studies furnished many practical equations to predict the scour geometry, such formulas are valid only in the tested range of parameters and they do not provide exhaustive insights on the physics of the process. This thesis follows the recent theoretical advancements pioneered by Bombardelli and collaborators, who derived completely theoretical formulas to predict the equilibrium scour depth of the pothole and its evolution under steady flow conditions, using dimensional arguments and the phenomenological theory of turbulence (PTT). We focused on the physics of the scour process under unsteady flow conditions and extended the theory proposed by Bombardelli et al. (2018). Our experimental data confirmed their findings, i.e., two phases occur during the scour evolution (developing and developed) regardless of the jet flow characteristics. The PTT-based model developed by Bombardelli et al. (2018) shows a good predicting capability of the scour evolution under unsteady flow conditions, thus confirming the validity of the scaling expression adopted for the shear stress. Our analysis provides further confirmations of the universal applicability of the PTT-based approach for jet-driven scour problems
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