855 resultados para Critical whiteness studies
Resumo:
This thesis engages black critical thought on the human and its contemporary iterations in posthumanism and transhumanism. It articulates five categories of analysis: displace, interrupt, disrupt, expand, and wither. Each is meant to allude to the generative potential in different iterations of black thought that engages the human. Working through Sylvia Wynter’s theories of the rise of Man-as-human in particular, the project highlights how black thought on the human displaces the uncritical whiteness of posthumanist thought. It argues that Afrofuturism has the potential to interrupt the linear progression from human to posthuman and that Octavia Butler’s Fledgling proffers a narrative of race as a technology that disrupts the presumed post-raciality of posthumanism and transhumanism. It then contends that Katherine McKittrick’s rearticulation of the Promise of Science can be extended to incorporate the promise of science fiction. In so doing, it avers that a more curated conversation between McKittrick and Wynter, one already ongoing, and Octavia Butler, through Mind of My Mind from her Patternist series, expands our notions of the human as a category even at the risk of seeing it wither as a politic or praxis. It ends on a speculative note meant to imagine the possibilities within the promise of science fiction.
Resumo:
This qualitative study explores the barriers and dilemmas faced by beginning and novice mentors in post-compulsory education in the southeast of England. It analyses critical incidents (Tripp, 2012) taken from the everyday practice of mentors who were supporting new teachers and lecturers in the southeast of England. It categorises different types of critical incidents that mentors encountered and describes the strategies and rationales mentors used to support mentees and (indirectly) their learners and colleagues. The study explores ways in which mentors' own values, beliefs and life experiences affected their mentoring practice. Methodology As part of a specialist master’s-level professional development module, 21 mentors wrote about two critical incidents (Tripp, 2012) taken from their own professional experiences, which aimed to demonstrate their support for their mentee’s range of complex needs. These critical incidents were written up as short case studies, which justified the rationale for their interventions and demonstrated the mentors' own professional development in mentoring. Critical incidents were used as units of analysis and categorised thematically by topic, sector and mentoring strategies used. Findings The research demonstrated the complex nature of decision-making and the potential for professional learning within a mentoring dyad. The study of these critical incidents found that mentors most frequently cited the controversial nature of teaching observations, the mentor’s role in mediating professional relationships, the importance of inculcating professional dispositions in education, and the need to support new teachers so that they can use effective behaviour management strategies. This study contributes to our understanding of the central importance of mentoring for professional growth within teacher education. It identifies common dilemmas that novice mentors face in post-compulsory education, justifies the rationale for their interventions and mentoring strategies, and helps to identify ways in which mentors' professional development needs can be met. It demonstrates that mentoring is complex, non-linear and mediated by mentors’ motivation and values.
Resumo:
The Ran GTPase protein is a guanine nucleotide-binding protein (GNBP) with an acknowledged profile in cancer onset, progression and metastases. The complex mechanism adopted by GNBPs in exchanging GDP for GTP is an intriguing process and crucial for Ran viability. The successful completion of the process is a fundamental aspect of propagating downstream signalling events. QM/MM molecular dynamics simulations were employed in this study to provide a deeper mechanistic understanding of the initiation of nucleotide exchange in Ran. Results indicate significant disruption of the metal-binding site upon interaction with RCC1 (the Ran guanine nucleotide exchange factor), overall culminating in the prominent shift of the divalent magnesium ion. The observed ion drifting is reasoned to occur as a consequence of the complex formation between Ran and RCC1 and is postulated to be a critical factor in the exchange process adopted by Ran. This is the first report to observe and detail such intricate dynamics for a protein in Ras superfamily.
Resumo:
Skeletal muscle wasting and weakness are major complications of critical illness and underlie the profound physical and functional impairments experienced by survivors after discharge from the intensive care unit (ICU). Exercise-based rehabilitation has been shown to be beneficial when delivered during ICU admission. This review aimed to determine the effectiveness of exercise rehabilitation initiated after ICU discharge on primary outcomes of functional exercise capacity and health-related quality of life. We sought randomized controlled trials, quasi-randomized controlled trials, and controlled clinical trials comparing an exercise intervention commenced after ICU discharge vs. any other intervention or a control or ‘usual care’ programme in adult survivors of critical illness. Cochrane Central Register of Controlled Trials, Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica Database, and Cumulative Index to Nursing and Allied Health Literature databases were searched up to February 2015. Dual, independent screening of results, data extraction, and quality appraisal were performed. We included six trials involving 483 patients. Overall quality of evidence for both outcomes was very low. All studies evaluated functional exercise capacity, with three reporting positive effects in favour of the intervention. Only two studies evaluated health-related quality of life and neither reported differences between intervention and control groups. Meta-analyses of data were precluded due to variation in study design, types of interventions, and selection and reporting of outcome measurements. We were unable to determine an overall effect on functional exercise capacity or health-related quality of life of interventions initiated after ICU discharge for survivors of critical illness. Findings from ongoing studies are awaited. Future studies need to address methodological aspects of study design and conduct to enhance rigour, quality, and synthesis.
Resumo:
Background
It is unknown whether a conservative approach to fluid administration or deresuscitation (active removal of fluid using diuretics or renal replacement therapy) is beneficial following haemodynamic stabilisation of critically ill patients.
Purpose
To evaluate the efficacy and safety of conservative or deresuscitative fluid strategies in adults and children with acute respiratory distress syndrome (ARDS), sepsis or systemic inflammatory response syndrome (SIRS) in the post-resuscitation phase of critical illness.
Methods
We searched Medline, EMBASE and the Cochrane central register of controlled trials from 1980 to June 2016, and manually reviewed relevant conference proceedings from 2009 to the present. Two reviewers independently assessed search results for inclusion and undertook data extraction and quality appraisal. We included randomised trials comparing fluid regimens with differing fluid balances between groups, and observational studies investigating the relationship between fluid balance and clinical outcomes.
Results
Forty-nine studies met the inclusion criteria. Marked clinical heterogeneity was evident. In a meta-analysis of 11 randomised trials (2051 patients) using a random-effects model, we found no significant difference in mortality with conservative or deresuscitative strategies compared with a liberal strategy or usual care [pooled risk ratio (RR) 0.92, 95 % confidence interval (CI) 0.82–1.02, I2 = 0 %]. A conservative or deresuscitative strategy resulted in increased ventilator-free days (mean difference 1.82 days, 95 % CI 0.53–3.10, I2 = 9 %) and reduced length of ICU stay (mean difference −1.88 days, 95 % CI −0.12 to −3.64, I2 = 75 %) compared with a liberal strategy or standard care.
Conclusions
In adults and children with ARDS, sepsis or SIRS, a conservative or deresuscitative fluid strategy results in an increased number of ventilator-free days and a decreased length of ICU stay compared with a liberal strategy or standard care. The effect on mortality remains uncertain. Large randomised trials are needed to determine optimal fluid strategies in critical illness.
Resumo:
Galactokinase, the enzyme which catalyses the first committed step in the Leloir pathway, has attracted interest due to its potential as a biocatalyst and as a possible drug target in the treatment of type I galactosemia. The mechanism of the enzyme is not fully elucidated. Molecular dynamics (MD) simulations of galactokinase with the active site residues Arg-37 and Asp-186 altered predicted that two regions (residues 174-179 and 231-240) had different dynamics as a consequence. Interestingly, the same two regions were also affected by alterations in Arg-105, Glu-174 and Arg- 228. These three residues were identified as important in catalysis in previous computational studies on human galactokinase. Alteration of Arg-105 to methionine resulted in a modest reduction in activity with little change in stability. When Arg-228 was changed to methionine, the enzyme’s interaction with both ATP and galactose was affected. This variant was significantly less stable than the wild-type protein. Changing Glu-174 to glutamine (but not to aspartate) resulted in no detectable activity and a less stable enzyme. Overall, these combined in silico and in vitro studies demonstrate the importance of a negative charge at position 174 and highlight the critical role of the dynamics in to key regions of the protein. We postulate that these regions may be critical for mediating the enzyme’s structure and function.
Resumo:
Incomplete reporting has been identified as a major source of avoidable waste in biomedical research.
Essential information is often not provided in study reports, impeding the identification, critical
appraisal, and replication of studies. To improve the quality of reporting of diagnostic accuracy
studies, the Standards for Reporting Diagnostic Accuracy (STARD) statement was developed. Here
we present STARD 2015, an updated list of 30 essential items that should be included in every
report of a diagnostic accuracy study. This update incorporates recent evidence about sources of
bias and variability in diagnostic accuracy and is intended to facilitate the use of STARD. As such,
STARD 2015 may help to improve completeness and transparency in reporting of diagnostic accuracy
studies.
Resumo:
Det amerikanska subjektets rekonstruktion: en studie av prisbelönad amerikansk skönlitterär prosa från 1990-talet
Resumo:
A Depressão na infância e adolescência, tal como na população adulta, é uma das perturbações mentais mais comuns. Uma vez que o seu aparecimento nestas faixas etárias conduz a graves consequências na idade adulta, é fundamental identificar os sintomas depressivos precocemente. Desta forma, os instrumentos de autorrelato têm um papel fundamental, uma vez que permitem com facilidade, de forma fidedigna e válida, ter acesso a formas de pensar, sentir e agir dos sujeitos. O objetivo do presente trabalho consistiu na tradução, adaptação e estudo da Center for Epidemiological Studies Depression Scale for Children (CES-DC) (Weissman, Orvash & Padian, 1980) para os adolescentes portugueses. A amostra é constituída por 417 adolescentes, com idades compreendidas entre os 12 e os 18 anos a frequentar o 3º ciclo do ensino básio e ensino secundário. Para o estudo da validade convergente e divergente da CES-DC, foram utilizados a Depression Anxiety Stress Scales (DASS 21) (Lovibond & Lovibond, 1995), o Children's Depresssion Inventory (CID) (Marujo, 1994) e a Students' Life Satisfaction Scale (SLSS) (Marques, Pais-Ribeiro & Lopez, 2007) que avaliam, respetivamente, os estados emocionais negativos (depressão, ansiedade e stress), a sintomatologia depressiva e a satisfação global com a vida. Os resultados obtidos mostram que a escala possui uma boa consistência interna, uma estabilidade temporal adequada, assim como uma boa validade. Sugerem, ainda, tratar-se de uma escala tridimensional: fator humor, fator interpessoal e fator felicidade. Estes dados permitem o avanço da Psicologia, no que diz respeito à avaliação e prática clínica com adolescentes. A utilidade do questionário deve ser verificada noutras faixas etárias, principalmente, nas de menos de 12 anos de idade, e também numa amostra clínica. Não obstante as limitações apontadas, os resultados sugerem que a CES-DC é um questionário útil na avaliação de sintomas depressivos nos adolescentes. / Depression in children and adolescents, as well as in adults, is one of the most common mental disorders. Since its appearance in these age groups leads to serious consequences in adulthood, it is critical to identify depressive symptoms in early stages. Therefore, self-report instruments play a key role in this contexto since they allow to easily, reliably and validly have access to ways the subject thinks, feels and acts. The aim of this study was to translate, adapt and study the Center for Epidemiological Studies Depression Scale for Children (CES-DC) (Weissman, Orvash & Padian, 1980) for portuguese adolescents. The sample consists of 417 adolescents, aged between 12 and 18 years old, attending the 3rd cycle of basic education and secondary education schools. To study the convergent and divergent validity of the CES-DC, the Depression Anxiety Stress Scales (DASS 21) (Lovibond & Lovibond, 1995) was used, along with the Children's depression Inventory (CDI) (Sailor, 1994) and the Students' Life Satisfaction Scale (SLSS) (Marques, Pais-Ribeiro & Lopez, 2007) that evaluate, respectively, the negative emotional states (depression, anxiety and stress), depressive symptoms and overall satisfaction with life. The results show that the evaluated scale presents a good internal consistency, an adequate temporal stability as well as good validity. They also suggest that this is a three-dimensional scale: humor factor, interpersonal factor and happiness factor. These data allow for the progress of psychology, regarding the assessment and clinical practice among adolescents. The usefulness of the questionnaire should be verified in other age groups, especially in children with less than 12 years old and in a clinical sample. Despite these limitations, the results suggest that CES-DC is useful in the assessment questionnaire of depressive symptoms in adolescents.
Resumo:
Moisture desorption observations from two bentonite clay mats subjected to ten environmental zones with individually different combinations of laboratory-controlled constant temperatures (between 20 °C and 40 °C) and relative humidity (between 15% and 70%) are presented. These laboratory observations are compared with predictions from mathematical models, such as thin-layer drying equations and kinetic drying models proposed by Page, Wang and Singh, and Henderson and Pabis. The quality of fit of these models is assessed using standard error (SE) of estimate, relative percent of error, and coefficient of correlation. The Page model was found to better predict the drying kinetics of the bentonite clay mats for the simulated tropical climates. Critical study on the drying constant and moisture diffusion coefficient helps to assess the efficacy of a polymer to retain moisture and control desorption through water molecule bonding. This is further substantiated with the Guggenheim–Anderson–De Boer (GAB) desorption isotherm model which is presented.
Resumo:
In the last thirty years, the emergence and progression of biologging technology has led to great advances in marine predator ecology. Large databases of location and dive observations from biologging devices have been compiled for an increasing number of diving predator species (such as pinnipeds, sea turtles, seabirds and cetaceans), enabling complex questions about animal activity budgets and habitat use to be addressed. Central to answering these questions is our ability to correctly identify and quantify the frequency of essential behaviours, such as foraging. Despite technological advances that have increased the quality and resolution of location and dive data, accurately interpreting behaviour from such data remains a challenge, and analytical methods are only beginning to unlock the full potential of existing datasets. This review evaluates both traditional and emerging methods and presents a starting platform of options for future studies of marine predator foraging ecology, particularly from location and two-dimensional (time-depth) dive data. We outline the different devices and data types available, discuss the limitations and advantages of commonly-used analytical techniques, and highlight key areas for future research. We focus our review on pinnipeds - one of the most studied taxa of marine predators - but offer insights that will be applicable to other air-breathing marine predator tracking studies. We highlight that traditionally-used methods for inferring foraging from location and dive data, such as first-passage time and dive shape analysis, have important caveats and limitations depending on the nature of the data and the research question. We suggest that more holistic statistical techniques, such as state-space models, which can synthesise multiple track, dive and environmental metrics whilst simultaneously accounting for measurement error, offer more robust alternatives. Finally, we identify a need for more research to elucidate the role of physical oceanography, device effects, study animal selection, and developmental stages in predator behaviour and data interpretation.
Resumo:
Single-walled carbon nanotubes (SWNTs) have been studied as a prominent class of high performance electronic materials for next generation electronics. Their geometry dependent electronic structure, ballistic transport and low power dissipation due to quasi one dimensional transport, and their capability of carrying high current densities are some of the main reasons for the optimistic expectations on SWNTs. However, device applications of individual SWNTs have been hindered by uncontrolled variations in characteristics and lack of scalable methods to integrate SWNTs into electronic devices. One relatively new direction in SWNT electronics, which avoids these issues, is using arrays of SWNTs, where the ensemble average may provide uniformity from device to device, and this new breed of electronic material can be integrated into electronic devices in a scalable fashion. This dissertation describes (1) methods for characterization of SWNT arrays, (2) how the electrical transport in these two-dimensional arrays depend on length scales and spatial anisotropy, (3) the interaction of aligned SWNTs with the underlying substrate, and (4) methods for scalable integration of SWNT arrays into electronic devices. The electrical characterization of SWNT arrays have been realized by polymer electrolyte-gated SWNT thin film transistors (TFTs). Polymer electrolyte-gating addresses many technical difficulties inherent to electrical characterization by gating through oxide-dielectrics. Having shown polymer electrolyte-gating can be successfully applied on SWNT arrays, we have studied the length scaling dependence of electrical transport in SWNT arrays. Ultrathin films formed by sub-monolayer surface coverage of SWNT arrays are very interesting systems in terms of the physics of two-dimensional electronic transport. We have observed that they behave qualitatively different than the classical conducting films, which obey the Ohm’s law. The resistance of an ultrathin film of SWNT arrays is indeed non-linear with the length of the film, across which the transport occurs. More interestingly, a transition between conducting and insulating states is observed at a critical surface coverage, which is called percolation limit. The surface coverage of conducting SWNTs can be manipulated by turning on and off the semiconductors in the SWNT array, leading to the operation principle of SWNT TFTs. The percolation limit depends also on the length and the spatial orientation of SWNTs. We have also observed that the percolation limit increases abruptly for aligned arrays of SWNTs, which are grown on single crystal quartz substrates. In this dissertation, we also compare our experimental results with a two-dimensional stick network model, which gives a good qualitative picture of the electrical transport in SWNT arrays in terms of surface coverage, length scaling, and spatial orientation, and briefly discuss the validity of this model. However, the electronic properties of SWNT arrays are not only determined by geometrical arguments. The contact resistances at the nanotube-nanotube and nanotube-electrode (bulk metal) interfaces, and interactions with the local chemical groups and the underlying substrates are among other issues related to the electronic transport in SWNT arrays. Different aspects of these factors have been studied in detail by many groups. In fact, I have also included a brief discussion about electron injection onto semiconducting SWNTs by polymer dopants. On the other hand, we have compared the substrate-SWNT interactions for isotropic (in two dimensions) arrays of SWNTs grown on Si/SiO2 substrates and horizontally (on substrate) aligned arrays of SWNTs grown on single crystal quartz substrates. The anisotropic interactions associated with the quartz lattice between quartz and SWNTs that allow near perfect horizontal alignment on substrate along a particular crystallographic direction is examined by Raman spectroscopy, and shown to lead to uniaxial compressive strain in as-grown SWNTs on single crystal quartz. This is the first experimental demonstration of the hard-to-achieve uniaxial compression of SWNTs. Temperature dependence of Raman G-band spectra along the length of individual nanotubes reveals that the compressive strain is non-uniform and can be larger than 1% locally at room temperature. Effects of device fabrication steps on the non-uniform strain are also examined and implications on electrical performance are discussed. Based on our findings, there are discussions about device performances and designs included in this dissertation. The channel length dependences of device mobilities and on/off ratios are included for SWNT TFTs. Time response of polymer-electrolyte gated SWNT TFTs has been measured to be ~300 Hz, and a proof-of-concept logic inverter has been fabricated by using polymer electrolyte gated SWNT TFTs for macroelectronic applications. Finally, I dedicated a chapter on scalable device designs based on aligned arrays of SWNTs, including a design for SWNT memory devices.
Resumo:
Abstract: The importance of e-government models lies in their offering a basis to measure and guide e-government. There is still no agreement on how to assess a government online. Most of the e-government models are not based on research, nor are they validated. In most countries, e-government has not reached higher stages of growth. Several scholars have shown a confusing picture of e-government. What is lacking is an in-depth analysis of e-government models. Responding to the need for such an analysis, this study identifies the strengths and weaknesses of major national and local e-government evaluation models. The common limitations of most models are focusing on the government and not the citizen, missing qualitative measures, constructing the e-equivalent of a bureaucratic administration, and defining general criteria without sufficient validations. In addition, this study has found that the metrics defined for national e-government are not suitable for municipalities, and most of the existing studies have focused on national e-governments even though local ones are closer to citizens. There is a need for developing a good theoretical model for both national and local municipal e-government.
Resumo:
Introduction and background: Survival following critical illness is associated with a significant burden of physical, emotional and psychosocial morbidity. Recovery can be protracted and incomplete, with important and sustained effects upon everyday life, including family life, social participation and return to work. In stark contrast with other critically ill patient groups (eg, those following cardiothoracic surgery), there are comparatively few interventional studies of rehabilitation among the general intensive care unit patient population. This paper outlines the protocol for a sub study of the RECOVER study: a randomised controlled trial evaluating a complex intervention of enhanced ward-based rehabilitation for patients following discharge from intensive care. Methods and analysis: The RELINQUISH study is a nested longitudinal, qualitative study of family support and perceived healthcare needs among RECOVER participants at key stages of the recovery process and at up to 1 year following hospital discharge. Its central premise is that recovery is a dynamic process wherein patients’ needs evolve over time. RELINQUISH is novel in that we will incorporate two parallel strategies into our data analysis: (1) a pragmatic health services-oriented approach, using an a priori analytical construct, the ‘Timing it Right’ framework and (2) a constructivist grounded theory approach which allows the emergence of new themes and theoretical understandings from the data. We will subsequently use Qualitative Health Needs Assessment methodology to inform the development of timely and responsive healthcare interventions throughout the recovery process. Ethics and dissemination: The protocol has been approved by the Lothian Research Ethics Committee (protocol number HSRU011). The study has been added to the UK Clinical Research Network Database (study ID. 9986). The authors will disseminate the findings in peer reviewed publications and to relevant critical care stakeholder groups.