3,306 research outputs found
Four dimensions to induce learning: The challenge profile.
No full textKnowledge generation is critical for company survival and managers need to face a new role: becoming educators. This requires an understanding of how knowledge is generated and what triggers individual learning. We propose that each individual has a personal predisposition to use a particular learning profile. Our findings show the Educational Dimensions Portfolio (EDP) as a gallery of profiles that match each individual's problem-solving challenge. A manager-educator can use the EDP model for triggering individual learning. We have verified, using statistical methods, that there are four EDP dimensions. They are related to both David Kolb's and Peter Honey's learning styles. We have verified that each individual has a personal predisposition to use a particular profile. We call it the challenge profile. That specific combination provides the individual's gateway not only to his own learning but also to inducing learning in others.manager as educator; innovation; challenge; learning styles; knowledge management;
The Effectiveness of Interventions on Sustained Childhood Physical Activity: A Systematic Review and Meta-Analysis of Controlled Studies
No full textBackground
Increased physical activity (PA) has been associated with a reduction in non-communicable disease risk factors and outcomes. However, interventions to increase childhood PA typically produce small to negligible effects. Recent reviews are limited due to lack of post-intervention follow-up measurement. This review aimed to examine measured effects at least six months post-intervention.
Methods and Findings
We searched PubMed, MEDLINE, EMBASE, PsychINFO, ScienceDirect, SportDiscus and Google Scholar between 1st January 1991 and 1st November 2014 for controlled studies reporting six-month post-intervention measurement for children aged 5 to 18 years. 14 studies met inclusion criteria; 12 reported moderate-to-vigorous PA (MVPA) (n = 5790) and 10 reported total PA (TPA) (n = 4855). We calculated overall effect estimates and 95% CI’s using random effects modelling with inverse variance weighting. Mean difference was calculated for MVPA, with standardised mean difference calculated to TPA due to measurement variation. Meta-regression assessed heterogeneity by continuous level variables. Negligible mean difference in MVPA existed in favour of the intervention group, amounting to 1.47 (95% CI -1.88, 4.82) mins/day compared to controls, while no difference was recorded on TPA. Sub-group analyses revealed males (2.65 mins/day: 95% CI 2.03, 3.27) reported higher levels of MVPA than females (-0.42 mins/day: 95% CI -7.77, 6.94), community settings (2.67 mins/day: 95% CI 2.05, 3.28) were more effective than school settings (1.70 mins/day: 95% CI -4.84, 8.25), and that treatment (4.47 mins/day: 95% CI -0.81, 9.76) demonstrated greater effects than population approaches (1.03 mins/day: 95% CI -2.54, 4.60). Meta-regression revealed no significant differences by factor on pooled effects. Significant heterogeneity existed between studies and potential for small study effects was present.
Conclusions
Improved PA levels subsequent to intervention were not maintained six month post-intervention. A potentially useful avenue of future research is to specifically explore community treatment of high risk individuals
Identification and imaging of lipids in tissues using TOF-SIMS
No full textIntroduction: Normal lipid metabolism in the adipose tissue, skeletal muscle and aortic wall
is important for the physiological function of these tissues. Dyslipidemia that is often
associated with intake of high energy diet and sedentary lifestyles can lead to the development
of insulin resistance and cardiovascular diseases. Existing methods for imaging the
heterogeneous distribution of lipids in the skeletal muscle and adipose tissue is limited. Our
aim is to, without probing and chemical fixation, identify and image the spatial distribution of
lipids in the skeletal muscle, adipose tissue and aorta, and to reveal an altered lipid pattern in
the skeletal muscle associated with obesity and in the aorta associated with high glucose
intake. To achieve this, we used time-of-flight secondary-ion mass spectrometry (TOF-SIMS)
equipped with a bismuth (Bi)-cluster gun which is a new technique for molecular imaging of
biological samples. Principal component analysis (PCA) was used for studying changes
between experimental and control groups.
Methods: Human adipose and skeletal muscle tissue were obtained from obese youths and
aortas were taken from Wistar Rats with or without glucose drinking. The samples were
prepared by high pressure freezing, freeze-fracturing. Gastrocnemius skeletal muscle was
taken from obese ob/ob mice and lean wild-type mice. The tissue was cryofixed and
cryosectionized. All samples were dehydrated by a freeze drying process in ultra high
vaacum. The tissue was analyzed by TOF-SIMS. Semi-quantitative measurements in the rat
aorta and in the mice skeletal muscle were based on principal component analysis.
Results: In the negative spectra, we identified fatty acids and triacylglycerol. In the positive
spectra, we identified the phosphocholine, cholesterol and diacylglycerol. Heterogeneous
distribution of these molecules was observed in the skeletal muscle and adipose tissue. By
using PCA, we identified a reduced signal of cholesterol in rats with high glucose intake
compared to control rats. The obese ob/ob mice showed an increased level of fatty acids and
diacylglycerol. The ratio between fatty acid peaks showed changed fatty acid composition in
the rat aorta associated with high glucose intake and in the mice skeletal muscle associated
with obesity.
Conclusions: With the help of imaging TOF-SIMS, it is possible to depict the heterogeneous
localization of fatty acids, phosphocholine, cholesterol, diacylglycerol and triacylglycerol in
the adipose tissue, skeletal muscle and aortic wall. Moreover, imaging TOF-SIMS together
with PCA analysis of TOF-SIMS spectra is a promising tool for studying lipid alterations in
tissues
Are forecasting models usable for policy analysis?
No full textIn this article, Christopher A. Sims argues the answer to his title is yes. Sims explains that any decisionmaking model must incorporate some identifying assumptions to enable it to forecast the effects of alternative decisions. He argues that although all identifying assumptions in econometric policymaking models are of uncertain validity, those incorporated in vector autoregression (VAR) forecasting models have the advantage of allowing their uncertainty to be measured. Sims concludes by demonstrating a method for identifying a small macroeconomic VAR model so that it can be used to analyze monetary policyForecasting ; Economic policy
The Effectiveness of Interventions on Sustained Childhood Physical Activity: A Systematic Review and Meta-Analysis of Controlled Studies
No full textDetection of hopanes and steranes in single oil-bearing fluid inclusions using ToF-SIMS
No full textHopanes and steranes are key biomarkers when tracking early evolution of life on Earth. A potential contamination-free source of Precambrian biomarkers is oil-bearing fluid inclusions as the oil has been secluded from the environment since the formation of the inclusion. Due to presence of often several generations of inclusions it can be problematic to assign the biomarkers to specific inclusions. It has, however, because of the small size of inclusions (5-30 µm), not been possible to analyse single oil-bearing fluid inclusions. We present here an approach employing time-of-flight secondary ion mass spectrometry (ToF-SIMS) to selectively open individual oil inclusions in situ by ion etching, and precisely analyse their picoliter content for steranes and hopanes. A number of oil-bearing inclusions from hydrothermal veins in the Siljan impact structure in south-central Sweden were analysed. The approach used for analysis of a single inclusion consisted of the following steps i) localization of suitable inclusion in double polished thin section with optical microscopy, ii) opening of inclusion by ion etching with C60+ gun inside the ToF-SIMS instrument while recording in real-time the opening of the inclusion and, iii) analysis of the exposed inclusion contents with ToF-SIMS. The micrographs and the ToF-SIMS ion images collected before, during and after analysis ensured the correct inclusion had been analysed. ToF-SIMS spectra reconstructed from analysis times and 2D regions of interest with increased organic ion signal showed a large number of organic peaks (up to m/z 500) that are characteristic for a crude oil. Comparison of the reconstructed spectra with those of a Siljan seep oil, which has previously been analysed with ToF-SIMS, showed a high degree of resemblance, as expected from the geological interpretation of the origin on the oils. All major characteristic peaks for several hopanes and steranes were detected in the mass spectra from the single fluid inclusion (Fig. 1). The agreement with respect to mass accuracy (< 50 ppm), fragment pattern and isotope distributions between these peaks and those observed in spectra from standard samples and from hopanes and steranes in the Siljan seep oil, provide strong evidence for the presence of hopanes and steranes in the analysed single fluid inclusions. The results thus demonstrate that the approach presented here has the capability to detect specific biomarkers in individual single oil inclusions. It is to our knowledge the first time hopanes and steranes have been detected in single oil-bearing fluid inclusins and the next step will be to analyse single oil-bearing fluid inclusions in Precambrian rocks with ToF-SIMS in search for organic biomarkers. Detection of hopanes and steranes in such an inclusion could help to answer questions regarding early evolution of life on Earth, including the first appearance of the eukaryotes on Earth.</p
Visualisation of amphetamine contamination in fingerprints using tof-sims technique
No full textTime-of-flight secondary ion mass spectrometry (TOF-SIMS) was applied to detect traces of amphetamine on fingerprints. In the present study, three different lift tapes and latent powder fingerprints were tested. The obtained results show that it is possible to identify traces of a drug as well as its distribution over the tested fingerprint after its transfer from the primary base onto an adhesive lifter (secondary base). Moreover, images obtained by the TOF-SIMS technique enable the observation of very small areas of the analysed fingerprint as well as the identification of micro-objects (residues of a contaminant) that were left on the fingerprint. The use of the black latent fingerprint powder did not interfere with the TOF-SIMS analysis, which makes it possible to effectively use this technique to study the traces of substances on the revealed fingerprints.ChemE/Advanced Soft Matte
Detection of organic biomarkers in crude oils using ToF-SIMS
No full textIn this study, we show that time of flight-secondary ion mass spectrometry (ToF-SIMS) can be used to detect organic biomarkers, such as hopanes and steranes, in non-fractionated crude oils, without extraction and chemical preparation. Hopanes and steranes may provide valuable information on the history of life on early Earth, particularly if they are present in fluid inclusions in ancient rocks. Due to the presence of different generations of inclusions in even very small rock samples, it would be advantageous to find a method capable of detecting biomarkers in single oil rich fluid inclusions. The capability of ToF-SIMS for detailed chemical analysis of very small sample amounts makes it a potential technique for such analysis, and in this work this possibility is explored. The presence of hopanes and steranes in four different crude oils of different ages and stages of biodegradation was investigated using ToF-SIMS and GC-MS. By combining analyses of biomarker standards, crude oils and chromatographic oil fractions, specific peaks for the different biomarkers were identified in the ToF-SIMS spectra. The presence of these peaks in the spectra from the crude oil samples could be attributed to the biomarkers based on exact mass determination and by comparison with the spectra from the biomarker containing and biomarker lacking fractions, respectively. In addition, the results show that a significant biomarker signal may be obtained from a 10 m,2 oil sample, demonstrating the potential of ToF-SIMS for analysis of single oil bearing fluid inclusions, which in turn may contribute to a better understanding of the early history of life on Earth. (C) 2008 Elsevier Ltd. All rights reserved
AN INTERVIEW WITH CHRISTOPHER A. SIMS
No full textChristopher Sims is a well-known intellectual leader in time-series econometrics and applied macroeconomics. Among his many honors and distinctions, he has been the President of the Econometric Society and he is a member of the National Academy of Sciences. He has made fundamental contributions to both statistical theory of time series and empirical macroeconomics. Sims work is influential precisely because it was motivated by important problems in macroeconomics. Not only did Sims study questions of statistical approximation in abstract environments, he showed how to apply the resulting apparatus to a variety of specific problems confronting applied researchers. The applications include seasonality in economic time series, aggregation over time, and approximation in formulating statistical models with economic underpinnings. Moreover, Sims contributions to causality in time series and to the development of vector autoregressive methods were complemented by an important body of empirical research. Sims has served as an effective advocate and critic of the extensively used vector autoregressive statistical methods. Motivated by his own and related empirical research, Sims is one of the leaders in rethinking how monetary policy should be modeled and reconsidering the channels by which monetary policy influences economic aggregates. This interview with Chris Sims gives an opportunity to explore further the context of many of these contributions. Sims typically has a unique perspective on many economic problems, a perspective that is articulated in his answers to a variety of questions.
A secularização segundo Peter L. Berger e Rodney Stark/William Sims Bainbridge
No full textEste estudo é sobre a secularização segundo Peter L. Berger (teoria da secularização) e segundo Rodney Stark/William Sims Bainbridge (teoria da escolha racional). Berger (capítulo 1) afirma, na obra O dossel sagrado, a diminuição da religião na modernidade, enquanto Stark/Bainbridge (capítulo 2) defendem, na obra Uma teoria da religião, seu aumento ou manutenção. Mas ambas as teorias apresentam problemas (capítulo 3); Berger é criticado porque afirma a equivalência entre modernidade e secularização, a crença em uma pregressa idade da fé e a necessidade de monopólio religioso; Stark/Bainbridge são criticados porque defendem o poder preditivo da teoria da escolha racional, uma racionalidade universal descontextualizada e uma abordagem puramente econômica do fenômeno religiosoThis study is about the secularization according to Peter L. Berger (theory of secularization) and according to Rodney Stark/William Sims Bainbridge (rational choice theory). Berger (chapter 1) affirms in Sacred Canopy the decrease of religion in modernity, whereas Stark/Bainbridge (chapter 2) supports in A theory of religion its increasing or maintenance. However, both theories have problems (chapter 3). Berger is criticized to affirm the equivalence between modernity and secularization, the belief in a previous age of the faith and the necessity of religious monopoly; Stark/Bainbridge are criticized to defend previous power of rational choice theory, a decontextualized universal rationality and an merely economic approach of religious phenomenonCoordenação de Aperfeiçoamento de Pessoal de Nível Superio
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