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1.
J Radiol Prot ; 43(4)2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37669663

RESUMO

In September 2022, the International Commission on Radiological Protection (ICRP) organised a workshop in Estoril, Portugal, on the 'Review and Revision of the System of Radiological Protection: A Focus on Research Priorities'. The workshop, which was a side event of the European Radiation Protection Week, offered an opportunity to comment on a recent paper published by ICRP on areas of research to support the System of Radiological Protection. Altogether, about 150 individuals participated in the workshop. After the workshop, 16 of the 30 organisations in formal relations with ICRP provided written feedback. All participants and organisations followed ICRP's view that further research in various areas will offer additional support in improving the System in the short, medium, and long term. In general, it was emphasised that any research should be outcome-focused in that it should improve protection of people or the environment. Many research topics mentioned by the participants were in line with those already identified by ICRP in the paper noted above. In addition, further ideas were expressed such as, for example, that lessons learned during the COVID-19 pandemic with regards to the non-radiological social, economic and environment impacts, should be analysed for their usefulness to enhance radiological protection, and that current protection strategies and application of current radiological protection principles may need to be adapted to military scenarios like those observed recently during the military conflict in the Ukraine or the detonation of a nuclear weapon. On a broader perspective, it was discussed how radiation research and radiological protection can contribute towards the Sustainable Development Goals announced by the United Nations in 2015. This paper summarises the views expressed during the workshop and the major take home messages identified by ICRP.

2.
Educ Inf Technol (Dordr) ; : 1-19, 2023 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-37361834

RESUMO

Designing strategic pedagogical change through the lens of a student experience that is yet to be experienced offers a critical frame for embedding the impacts of transition, uncertainty, belonging and the complexity of the student journey into the co-design of teaching and learning. A digital storytelling approach extends the notion of the student experience beyond the singular and metricised descriptions common in online student satisfaction survey instruments into a rhizomatic, resonant living community that resides in the intersecting spaces of work, life, play and learning. This paper describes an ethnographic-like model of collecting and evaluating the student experience through a semi-structured digital storytelling methodology that supports both co-design and cogenerative dialogue as a form of curriculum enhancement. The paper outlines how the Student Experience Digital Storytelling model was iteratively designed, deployed, and then evaluated through participatory action research-informed case studies at the University of Sydney Business School (Australia) and the London School of Economics and Political Science (United Kingdom) that embedded the student experience into the co-design of curriculum and assessment interventions.

3.
J Surg Res ; 280: 557-566, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36096021

RESUMO

INTRODUCTION: Traumatic brain injury (TBI) management includes serial neurologic examinations to assess for changes dictating neurosurgical interventions. We hypothesized hourly examinations are overassigned. We conducted a decision tree analysis to determine an algorithm to judiciously assign hourly examinations. METHODS: A retrospective cohort study of 1022 patients with TBI admitted to a Level 1 trauma center from January 1, 2019, to December 31, 2019, was conducted. Patients with penetrating TBI or immediate or planned interventions and those with nonsurvivable injuries were excluded. Patients were stratified by whether they underwent an unplanned intervention (e.g., craniotomy or invasive intracranial monitoring). Univariate analysis identified factors for inclusion in chi-square automatic interaction detection technique, classifying those at risk for unplanned procedures. RESULTS: A total of 830 patients were included, 287 (35%) were assigned hourly (Q1) examinations, and 17 (2%) had unplanned procedures, with 16 of 17 (94%) on Q1 examinations. Patients requiring unplanned procedures were more likely to have mixed intracranial hemorrhage pattern (82% versus 39%; P = 0.001), midline shift (35% versus 14%; P = 0.023), an initial poor neurologic examination (Glasgow Comas Scale ≤8, 77% versus 14%; P < 0.001), and be intubated (88% versus 17%; P < 0.001). Using chi-square automatic interaction detection, the decision tree demonstrated low-risk (2% misclassification) and excellent discrimination (area under the curve = 0.915, 95% confidence interval 0.844-0.986; P < 0.001) of patients at risk of an unplanned procedure. By following the algorithm, 167 fewer patients could have been assigned Q1 examinations, resulting in an estimated 6012 fewer examinations. CONCLUSIONS: Using a 4-factor algorithm can optimize the assignment of neuro examinations and substantially reduce neuro examination burden without sacrificing patient safety.


Assuntos
Lesões Encefálicas Traumáticas , Humanos , Estudos Retrospectivos , Lesões Encefálicas Traumáticas/complicações , Lesões Encefálicas Traumáticas/diagnóstico , Escala de Coma de Glasgow , Centros de Traumatologia , Exame Neurológico
4.
Exp Gerontol ; 163: 111803, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35413409

RESUMO

INTRODUCTION: Many falls in older adults are due to a loss of mediolateral stability during gait. This investigation examines if a simple beam-walking task can assess fall risk in older adults by taxing mediolateral control during gait. MATERIAL AND METHODS: 50 older adults (65-96 yrs.) and 20 younger adults (20-35 yrs.) walked along three 6 m long beams (12, 9 and 6 cm wide). Distance walked, number of steps and velocity were recorded. Participants also completed the Narrow Path Walking Test on a computerized gait mat and walked unrestricted across the mat. The number of falls in the 6 months pre- and post-testing were recorded. RESULTS: The beam data revealed significant differences between fallers and non-fallers in distance walked and number of steps taken on the 9 cm beam but not on the other beam widths. The coefficient of variation (CV) for step time and step length for unrestricted walking and for the NPWT were also significantly different between fallers and non-fallers. Falls in the 6 months before testing was not correlated with gait velocity but was significantly correlated with the number of steps and the distance walked on the 9 cm beam and with step length and step time CV. Falls in the 6 months following testing were strongly correlated with distance walked on the 9 cm beam. CONCLUSION: This research suggests that examining an older adult's ability to walk on a 9 cm wide beam might contribute significantly to the assessment of that person's fall risk.


Assuntos
Marcha , Caminhada , Acidentes por Quedas/prevenção & controle , Idoso , Suscetibilidade a Doenças , Humanos , Teste de Caminhada
5.
J Radiol Prot ; 41(4)2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34181587

RESUMO

There is widespread recognition of the challenge of an ageing profession and the need to recruit, train and retain the next generation of radiation protection professionals. This challenge was the topic of a special session at the International Radiation Protection Association IRPA15 International Congress. It is necessary to address three key aspects: capturing the future professional: gaining RP knowledge and skills: addressing retention, development and career progression. We must support the flow of students into science-based topics and attractively promote our profession. The availability of university and other training courses, together with research opportunities, must be supported. Mentoring of young professionals is key, supported by empathetic seniors in the profession. The overall challenge necessitates cooperation across a wide range of organisations at both international and national level.


Assuntos
Proteção Radiológica , Humanos
6.
J Radiol Prot ; 41(3)2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-33853040

RESUMO

Over the last 10 years there have been increasing concerns raised about a potential skills gap in the field of radiation protection (RP). Noting these concerns in 2019, the Society for Radiological Protection, the UK's Chartered Professional Body, launched a study to determine the RP demand in the UK going forward along with the capacity of the profession. The initial results show that over 50% of the SRP membership retires in the next 10-15 years, coupled with an increase in RP demand across the nuclear fuel cycle, medical sector and advancement of new technologies or applications requiring RP advice. This provides strong evidence supporting the concerns of a future skills gap. This paper presents a framework highlighting three core objectives that need to be met to resolve the skills gap. A review of the existing initiatives being undertaken by the Society of Radiological Protection to meet these objectives is included, identifying both areas of good practice and areas for further work and development. A key theme in tackling this challenge has been identified as the need to foster greater collaboration between RP professionals, and organizations both within the UK and abroad, such as IRPA, national societies, employers, academia and industry. This brings a unique opportunity to direct efforts and resources toward a common goal, allowing the sharing of good practice, whilst reducing the strain and burden on any one organization. Another key output of the review was the need to embrace new and innovative solutions to developing our profession and importantly inspiring and communicating into the future of the profession.


Assuntos
Proteção Radiológica , Previsões , Humanos , Sociedades
7.
Environ Resour Econ (Dordr) ; 76(4): 1107-1115, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32836829

RESUMO

The COVID-19 imposed lockdown has led to a number of temporary environmental side effects (reduced global emissions, cleaner air, less noise), that the climate community has aspired to achieve over a number of decades. However, these benefits have been achieved at a massive cost to welfare and the economy. This commentary draws lessons from the COVID-19 crisis for climate change. It discusses whether there are more sustainable ways of achieving these benefits, as part of a more desirable, low carbon resilient future, in a more planned, inclusive and less disruptive way. In order to achieve this, we argue for a clearer social contract between citizens and the state. We discuss how COVID-19 has demonstrated that behaviours can change abruptly, that these changes come at a cost, that we need a 'social mandate' to ensure these changes remain in the long-term, and that science plays an important role in informing this process. We suggest that deliberative engagement mechanisms, such as citizens' assemblies and juries, could be a powerful way to build a social mandate for climate action post-COVID-19. This would enable behaviour changes to become more accepted, embedded and bearable in the long-term and provide the basis for future climate action.

8.
Biol Bull ; 237(2): 111-118, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31714853

RESUMO

Despite the fact that Hydra has been studied for more than 200 years, we know surprisingly little about its life history. We show that Hydra vulgaris embryos hatch sporadically over a period ranging from a few days to nine months. We also report, for what seems to be the first time, the presence of Hydra in a vernal pool. Phylogenetic analysis and sexual crossing show that this Hydra is a member of the cosmopolitan Vulgaris clade and is not reproductively isolated from other members of the clade. Our findings lead us to hypothesize that Hydra evolved in an unstable freshwater habitat in which survival required that its life cycle include the use of a bet-hedging reproductive strategy and the formation of an embryo that is desiccation resistant and that can remain dormant for long periods of time.


Assuntos
Hydra , Animais , Filogenia , Reprodução , Estações do Ano
9.
PLoS One ; 14(10): e0218848, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31652271

RESUMO

Most, but not all cnidarian species in the class Hydrozoa have a life cycle in which a colonial, asexually reproducing hydroid phase alternates with a free-swimming, sexually reproducing medusa phase. They are not well known, in part because many of them are microscopic, at least in the medusa phase. Matching the two phases has previously required rearing of the organism from one phase to another, which has not often been possible. Here we show that DNA barcoding makes it possible to easily link life-cycle phases without the need for laboratory rearing. Hydrozoan medusae were collected by zooplankton tows in Newport Bay and the Pacific Ocean near Newport Beach, California, and hydroid colonies were collected from solid substrates in the same areas. Specimens were documented by videomicroscopy, preserved in ethanol, and sent to the Canadian Centre for DNA Barcoding at the University of Guelph, Ontario, Canada for sequencing of the COI DNA barcode. In the order Anthoathecata (athecate hydroids), DNA barcoding allowed for the discrimination between the medusae of eight putative species of Bougainvillia, and the hydroid stages were documented for two of these. The medusae of three putative species of Amphinema were identified, and the hydroid stages were identified for two of them. DNA barcodes were obtained from medusae of one species of Cladonema, one adult of the by-the wind Sailor, Velella velella, five putative species of Corymorpha with the matching hydroid phase for one; and Coryne eximia, Turritopsis dohrnii and Turritopsis nutricula with the corresponding hydroid phases. The actinula larvae and hydroid for the pink-hearted hydroid Ectopleura crocea were identified and linked by DNA barcoding. In the order Leptothecata (thecate hydroids) medusae were identified for Clytia elsaeoswaldae, Clytia gracilis and Clytia sp. 701 AC and matched with the hydroid phases for the latter two species. Medusae were matched with the hydroid phases for two species of Obelia (including O. dichotoma) and Eucheilota bakeri. Obelia geniculata was collected as a single hydroid. DNA barcodes were obtained for hydroids of Orthopyxis everta and three other species of Orthopyxis. One member of the family Solmarisidae, representing the order Narcomedusae, and one member (Liriope tetraphylla) of the order Trachymedusae were recognized as medusae. The results show the utility of DNA barcoding for matching life-cycle stages as well as for documenting the diversity of this class of organisms.


Assuntos
Biodiversidade , Código de Barras de DNA Taxonômico , Hidrozoários , Estágios do Ciclo de Vida/fisiologia , Zooplâncton , Animais , Hidrozoários/classificação , Hidrozoários/genética , Hidrozoários/crescimento & desenvolvimento , Microscopia de Vídeo , Oceano Pacífico , Zooplâncton/genética , Zooplâncton/crescimento & desenvolvimento
10.
Front Psychol ; 10: 194, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30800088

RESUMO

A personality scale that identifies individuals' general attitude to what happens to them as largely a matter of luck or fate or of powerful others (externality) or whether they feel they can influence the consequences (internality) is known as locus of control (LOC). A continuous scale can distinguish those who are more external from those who are more internal. Lower scholastic achievement is associated with externality and higher achievement with internality, but little is known about the association of parental LOC on children's academic performance. Data collected within the Avon Longitudinal Study of Parents and Children (ALSPAC) are analyzed to assess associations between mothers' LOC orientation, measured during pregnancy, and their children's abilities in mathematics and science reasoning. We found that maternal external LOC is associated with lower scores for her child assessed by tests measuring mental arithmetic as well as understanding of mathematical and scientific concepts. Additionally, we determined the extent to which three separate sets of factors previously found to positively influence the developing child's ability mediate these findings: (a) perinatal and infant exposures, such as prenatal smoking, binge drinking, consumption of oily fish, and postnatal breast feeding; (b) parenting attitudes and strategies; and (c) the interface of the parents with their child's school. The three factors identify at least 50% of the mechanism by which maternal externality is associated with poor academic outcomes in her child and may be candidates for further investigation as possible intervention targets.

11.
Sci Rep ; 7: 46317, 2017 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-28397869

RESUMO

Wettability is the affinity of a liquid for a solid surface. For energetic reasons, macroscopic drops of liquid form nearly spherical caps. The degree of wettability is then captured by the contact angle where the liquid-vapor interface meets the solid-liquid interface. As droplet volumes shrink to the scale of attoliters, however, surface interactions become significant, and droplets assume distorted shapes. In this regime, the contact angle becomes ambiguous, and a scalable metric for quantifying wettability is needed, especially given the emergence of technologies exploiting liquid-solid interactions at the nanoscale. Here we combine nanoscale experiments with molecular-level simulation to study the breakdown of spherical droplet shapes at small length scales. We demonstrate how measured droplet topographies increasingly reveal non-spherical features as volumes shrink. Ultimately, the nanoscale droplets flatten out to form layer-like molecular assemblies at the solid surface. For the lack of an identifiable contact angle at small scales, we introduce a droplet's adsorption energy density as a new metric for a liquid's affinity for a surface. We discover that extrapolating the macroscopic idealization of a drop to the nanoscale, though it does not geometrically resemble a realistic droplet, can nonetheless recover its adsorption energy if line tension is included.

12.
Nano Lett ; 17(5): 2741-2746, 2017 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-28414911

RESUMO

Analysis of nanoscale liquids, including wetting and flow phenomena, is a scientific challenge with far reaching implications for industrial technologies. We report the conception, development, and application of an integrated platform for the experimental characterization of liquids at the nanometer scale. The platform combines the functionalities of a two-dimensional electronic array of sensor devices with in situ application of highly sensitive optical microspectroscopy and atomic force microscopy. We demonstrate the performance capabilities of the platform with an embodiment based on an array of optically transparent graphene sensors. The application of electronic and optical sensing in the platform allows for differentiating between liquids electronically, for determining a liquid's molecular fingerprint, and for monitoring surface wetting dynamics in real time. In order to explore the platform's sensitivity limits, we record topographies and optical spectra of individual, spatially isolated sessile oil emulsion droplets having volumes of less than ten attoliters. The results demonstrate that integrated measurement functionalities based on two-dimensional materials have the potential to push lab-on-chip based analysis from the microscale to the nanoscale.

13.
Sci Rep ; 7: 43273, 2017 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-28230183

RESUMO

Drosophila imaginal disc growth factor 2 (IDGF2) is a member of chitinase-like protein family (CLPs) able to induce the proliferation of imaginal disc cells in vitro. In this study we characterized physiological concentrations and expression of IDGF2 in vivo as well as its impact on the viability and transcriptional profile of Drosophila cells in vitro. We show that IDGF2 is independent of insulin and protects cells from death caused by serum deprivation, toxicity of xenobiotics or high concentrations of extracellular adenosine (Ado) and deoxyadenosine (dAdo). Transcriptional profiling suggested that such cytoprotection is connected with the induction of genes involved in energy metabolism, detoxification and innate immunity. We also show that IDGF2 is an abundant haemolymph component, which is further induced by injury in larval stages. The highest IDGF2 accumulation was found at garland and pericardial nephrocytes supporting its role in organismal defence and detoxification. Our findings provide evidence that IDGF2 is an important trophic factor promoting cellular and organismal survival.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/imunologia , Drosophila/metabolismo , Metabolismo Energético , Glicoproteínas/metabolismo , Imunidade Inata , Inativação Metabólica , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Perfilação da Expressão Gênica , Hemolinfa/química
14.
Radiat Prot Dosimetry ; 173(1-3): 93-99, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-27885081

RESUMO

Across the world, we are seeing a resurgence in Nuclear New Build. In the UK alone, plans are under way for the construction of 10 new reactors, using 4 different reactor designs all of which are to be provided by foreign vendors, and operated by 3 newly formed licensees within the UK. As these new licensees embark on the task of establishing themselves and progressing the design and build of these reactors, there are challenges faced in integrating the Radiation Protection Requirements and Culture from the various Foreign Investors and Vendors into the UK 'Context'. The following paper identifies the origin of the Radiation Protection Requirements within the UK and foreign investor/vendor countries, in an attempt to integrate them into the UK licensing and approval process. Thus, allowing due credit to be taken for the regulatory regime of the foreign countries where these reactors originate.


Assuntos
Reatores Nucleares , Proteção Radiológica , Humanos , Reino Unido
15.
Artigo em Inglês | MEDLINE | ID: mdl-25585392

RESUMO

The route to phase-pure BiFeO3 (BFO) ceramics with excellent ferroelectric and electromechanical properties is severely impeded by difficulties associated with the perovskite phase stability during synthesis. This has meant that dopants and solid solutions with BFO have been investigated as a means of not only improving the functional properties, but also of improving the perovskite phase formation of BFO-based ceramics. The present work focuses on Sm-modified BFO ceramics of composition Bi0.88Sm0.12FeO3. The polarization and strain behaviors were investigated as a function of the phase composition, microstructure, and chemical composition. Addition of Sm reduces the susceptibility of the BFO perovskite to phase degradation by Si impurities. Si was observed to react into Sm-rich grains dispersed within the microstructure, with no large increases in the amount of bismuth-parasitic phases, namely Bi25FeO39 and Bi2Fe4O9. These as-prepared ceramics exhibited robust polarization behavior showing maximum remnant polarizations of ~40 to 50 µC/cm(2). The electric-fieldinduced strain showed an appreciable stability in terms of the driving field frequency with maximum peak-to-peak strains of ~0.3% and a coercive field of ~130 kV/cm.


Assuntos
Bismuto/química , Cerâmica/química , Compostos Férricos/química , Compostos de Cálcio , Teste de Materiais , Óxidos , Titânio , Difração de Raios X
16.
Br J Educ Psychol ; 84(Pt 2): 211-25, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24251419

RESUMO

BACKGROUND: Most psychologists who study children's reading assume that their hypotheses are relevant to children's success at school. This assumption is rarely tested. AIMS: The study's aims were to see whether two successful measures of the processes underlying children's learning to read and write are related to their success in English, science, and mathematics as measured by school assessments. SAMPLE: Data from the Avon Longitudinal Study of Parents and Children were available for between 2,500 and 5,900 children (in different analyses) on their use of graphophonic and morphemic units in reading and writing and on their achievement in Key Stage 2 and Key Stage 3 assessments. METHOD: Hierarchical multiple regressions assessed the relationship between children's use of grapho-phonic and morphemic units at 8- and 9-years and their performance in the Key Stage 2 (11-years) and Key Stage 3 (14-years) assessments in English, mathematics, and science. RESULTS: The children's grapho-phonic and morphemic skills predicted their achievement in all three subjects at Key Stage 2, 3 years later, and at Key Stage 3, 5 years later, even after stringent controls for differences in age and IQ. The connection between the two types of orthographic skills and the children's educational success was largely mediated by their reading ability as measured by standardised tests. CONCLUSIONS: Children's knowledge and use of grapho-phonic and morphemic rules has a lasting effect on the progress that they make at school. This knowledge has an impact on their reading ability which in turn affects their success in learning about English, mathematics and science.


Assuntos
Logro , Aprendizagem , Matemática/estatística & dados numéricos , Fonética , Leitura , Ciência/estatística & dados numéricos , Adolescente , Fatores Etários , Aptidão , Criança , Apresentação de Dados , Avaliação Educacional/métodos , Avaliação Educacional/estatística & dados numéricos , Inglaterra , Feminino , Humanos , Idioma , Estudos Longitudinais , Masculino , Análise de Componente Principal , Análise de Regressão , Redação
17.
Mutagenesis ; 27(6): 737-41, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22935224

RESUMO

Previous studies from our laboratory have identified a link between intracellular topoisomerase IIα (topo IIα) levels and chromosomal radiosensitivity, as measured by the frequencies of chromatid breaks in the so-called G2-assay. Lower topo IIα levels were associated with reduced chromosomal radiosensitivity in cultured human cells. These findings supported a model, in which it is proposed that such chromatid breaks are the result of radiation-induced errors made by topoisomerase IIα during decatenation of chromatids. Studies from our and other laboratories, using the G2-assay, have shown that phytohaemagglutinin (PHA)-stimulated peripheral blood T-lymphocytes from 40% of female breast cancer cases show elevated chromatid break frequencies when exposed to a small standard dose of ionizing radiation, i.e. elevated above the 90th percentile of a group of female control samples. In the present study we have used a modified G2-assay to test whether elevated frequency of chromatid breaks in breast cancer cases is linked with elevated intracellular topo IIα level in PHA-stimulated T-lymphocytes, and also whether there is a general correlation between chromosomal radiosensitivity and topo IIα level. Our results confirm previous studies that 40% of breast cancer cases show elevated radiosensitivity as compared with controls. Also, the mean chromatid break frequency in breast cancer cases was significantly higher than in controls (P = 0.0001). We found that the mean topo IIα level in the cohort of breast cancer cases studied was significantly raised, as compared with controls (P = 0.0016), which could indicate a genetic propensity towards a raised intracellular production of topo IIα in these individuals. There was no direct correlation between chromosomal radiosensitivity and topo IIα level for individual samples either in the breast cancer cohort or in controls. However, a comparison between control and breast cancer samples shows a higher mean topo IIα level in breast cancer samples that correlates with the elevated mean chromatid break frequency seen in these patient samples. We found no meaningful correlations between either chromatid break frequency or topo IIα level and either tumour grade or hormone status. We conclude that elevated intracellular topo IIα level is likely to be a significant factor in determining the chromosomal response of stimulated T-lymphocytes from certain breast cancer cases.


Assuntos
Antígenos de Neoplasias/análise , Neoplasias da Mama/genética , Dano ao DNA , DNA Topoisomerases Tipo II/análise , Proteínas de Ligação a DNA/análise , Tolerância a Radiação/genética , Linfócitos T/efeitos da radiação , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/patologia , Estudos de Casos e Controles , Linhagem Celular Tumoral , Cromátides/genética , Cromossomos Humanos , Feminino , Humanos , Pessoa de Meia-Idade , Radiação Ionizante , Linfócitos T/metabolismo
18.
J Exp Child Psychol ; 113(4): 469-86, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22995445

RESUMO

Recent research on children's conceptual and procedural knowledge has suggested that there are individual differences in the ways that children combine these two types of knowledge across a number of mathematical topics. Cluster analyses have demonstrated that some children have more conceptual knowledge, some children have more procedural knowledge, and some children have an equal level of both. The current study investigated whether similar individual differences exist in children's understanding of fractions and searches for explanations for these differences. Grade 6 students (n=119) and Grade 8 students (n=114) were given measures of conceptual and procedural knowledge of fractions as well as measures of general fraction knowledge, general conceptual ability, and general procedural ability. Grade 6 children demonstrated a four-cluster solution reflecting those who do poorly on procedural and conceptual fraction knowledge, those who do well on both, those whose strength is procedural knowledge, and those whose strength is conceptual knowledge. Grade 8 children demonstrated a two-cluster solution reflecting those whose strength is procedural knowledge and those whose strength is conceptual knowledge. Cluster in either grade, however, did not vary in distribution across schools and was not related to general conceptual ability or general procedural ability. Overall, these results provide a more detailed picture of individual differences in conceptual and procedural knowledge in mathematical cognition.


Assuntos
Aptidão , Compreensão , Formação de Conceito , Individualidade , Matemática , Resolução de Problemas , Adolescente , Criança , Feminino , Humanos , Masculino , Reconhecimento Psicológico , Reino Unido
19.
Br J Educ Psychol ; 82(Pt 1): 136-56, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22429062

RESUMO

BACKGROUND: Two distinct abilities, mathematical reasoning and arithmetic skill, might make separate and specific contributions to mathematical achievement. However, there is little evidence to inform theory and educational practice on this matter. AIMS: The aims of this study were (1) to assess whether mathematical reasoning and arithmetic make independent contributions to the longitudinal prediction of mathematical achievement over 5 years and (2) to test the specificity of this prediction. SAMPLE: Data from Avon Longitudinal Study of Parents and Children (ALSPAC) were available on 2,579 participants for analyses of KS2 achievement and on 1,680 for the analyses of KS3 achievement. METHOD: Hierarchical regression analyses were used to assess the independence and specificity of the contribution of mathematical reasoning and arithmetic skill to the prediction of achievement in KS2 and KS3 mathematics, science, and English. Age, intelligence, and working memory (WM) were controls in these analyses. RESULTS: Mathematical reasoning and arithmetic did make independent contributions to the prediction of mathematical achievement; mathematical reasoning was by far the stronger predictor of the two. These predictions were specific in so far as these measures were more strongly related to mathematics than to science or English. Intelligence and WM were non-specific predictors; intelligence contributed more to the prediction of science than of maths, and WM predicted maths and English equally well. CONCLUSIONS: There is clear justification for making a distinction between mathematical reasoning and arithmetic skills. The implication is that schools must plan explicitly to improve mathematical reasoning as well as arithmetic skills.


Assuntos
Logro , Aptidão , Conceitos Matemáticos , Resolução de Problemas , Criança , Inglaterra , Feminino , Humanos , Estudos Longitudinais , Masculino , Memória de Curto Prazo , Psicometria , Escalas de Wechsler/estatística & dados numéricos
20.
Langmuir ; 27(6): 2176-80, 2011 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-21338126

RESUMO

The film formation of an acrylate latex with a glass-transition temperature of 38 °C has been achieved through the use of near-infrared (NIR) radiative heating. A hard, crack-free coating was obtained without the addition of plasticizers. Sintering of acrylate particles was confirmed through measurements using atomic force microscopy. The addition of an NIR-absorbing polymer increased the rate of particle deformation such that it was significantly greater than obtained in a convection oven at 60 °C. The results are consistent with a lower polymer viscosity under infrared radiation, according to a simple analysis using a standard model of sintering.

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