161 research outputs found
Evolution education. A study of teachers\u27 pedagogical content knowledge
Ausgangspunkt dieser Studie war die Entwicklung des Modells der Didaktischen Rekonstruktion für Lehrerbildung. Das Modell bildet den integrativen Rahmen für Studien zum fachdidaktischen Wissen von Lehrkräften. Die vorliegende Studie über fachdidaktisches Wissen zur Evolution gibt einen Einblick darin, welche Kenntnisse die Lehrenden von den Verständnisproblemen der Lernenden mit der Evolutionstheorie haben und wie sie auf diese Probleme reagieren. Außerdem zeigt die Studie exemplarisch, wie die fachlichen und pädagogischen Kenntnisse der Lehrenden ihr fachdidaktisches Wissen beeinflussen. (DIPF/Orig.)The starting point of the research project has been the development of the Model of Educational Reconstruction for Teacher Education (ERTE-Model), which constitutes the basis for studies of teachers\u27 Pedagogical Content Knowledge (PCK). The PCK-study on evolution provides detailed insights into the knowledge that teachers have of the students\u27 difficulties with understanding evolutionary theory, in relation to the teachers\u27 ways to react to these problems. In addition, the study demonstrates how the teachers\u27 subject matter knowledge and pedagogical knowledge influence their PCK. (DIPF/Orig.
Effects of macronutrient intake in obesity:A meta-analysis of low-carbohydrate and low-fat diets on markers of the metabolic syndrome
The metabolic syndrome (MetS) comprises cardiometabolic risk factors frequently found in individuals with obesity. Guidelines to prevent or reverse MetS suggest limiting fat intake, however, lowering carbohydrate intake has gained attention too. The aim for this review was to determine to what extent either weight loss, reduction in caloric intake, or changes in macronutrient intake contribute to improvement in markers of MetS in persons with obesity without cardiometabolic disease. A meta-analysis was performed across a spectrum of studies applying low-carbohydrate (LC) and low-fat (LF) diets. PubMed searches yielded 17 articles describing 12 separate intervention studies assessing changes in MetS markers of persons with obesity assigned to LC (<40% energy from carbohydrates) or LF (<30% energy from fat) diets. Both diets could lead to weight loss and improve markers of MetS. Meta-regression revealed that weight loss most efficaciously reduced fasting glucose levels independent of macronutrient intake at the end of the study. Actual carbohydrate intake and actual fat intake at the end of the study, but not the percent changes in intake of these macronutrients, improved diastolic blood pressure and circulating triglyceride levels, without an effect of weight loss. The homeostatic model assessment of insulin resistance improved with both diets, whereas high-density lipoprotein cholesterol only improved in the LC diet, both irrespective of aforementioned factors. Remarkably, changes in caloric intake did not play a primary role in altering MetS markers. Taken together, these data suggest that, beyond the general effects of the LC and LF diet categories to improve MetS markers, there are also specific roles for weight loss, LC and HF intake, but not reduced caloric intake, that improve markers of MetS irrespective of diet categorization. On the basis of the results from this meta-analysis, guidelines to prevent MetS may need to be re-evaluated
Optimised padlock probe ligation and microarray detection of multiple (non-authorised) GMOs in a single reaction
Background To maintain EU GMO regulations, producers of new GM crop varieties need to supply an event-specific method for the new variety. As a result methods are nowadays available for EU-authorised genetically modified organisms (GMOs), but only to a limited extent for EU-non-authorised GMOs (NAGs). In the last decade the diversity of genetically modified (GM) ingredients in food and feed has increased significantly. As a result of this increase GMO laboratories currently need to apply many different methods to establish to potential presence of NAGs in raw materials and complex derived products. Results In this paper we present an innovative method for detecting (approved) GMOs as well as the potential presence of NAGs in complex DNA samples containing different crop species. An optimised protocol has been developed for padlock probe ligation in combination with microarray detection (PPLMD) that can easily be scaled up. Linear padlock probes targeted against GMO-events, -elements and -species have been developed that can hybridise to their genomic target DNA and are visualised using microarray hybridisation. In a tenplex PPLMD experiment, different genomic targets in Roundup-Ready soya, MON1445 cotton and Bt176 maize were detected down to at least 1%. In single experiments, the targets were detected down to 0.1%, i.e. comparable to standard qPCR. Conclusion Compared to currently available methods this is a significant step forward towards multiplex detection in complex raw materials and derived products. It is shown that the PPLMD approach is suitable for large-scale detection of GMOs in real-life samples and provides the possibility to detect and/or identify NAGs that would otherwise remain undetecte
Comparison and transfer testing of multiplex ligation detection methods for GM plants
<p>Abstract</p> <p>Background</p> <p>With the increasing number of GMOs on the global market the maintenance of European GMO regulations is becoming more complex. For the analysis of a single food or feed sample it is necessary to assess the sample for the presence of many GMO-targets simultaneously at a sensitive level. Several methods have been published regarding DNA-based multidetection. Multiplex ligation detection methods have been described that use the same basic approach: i) hybridisation and ligation of specific probes, ii) amplification of the ligated probes and iii) detection and identification of the amplified products. Despite they all have this same basis, the published ligation methods differ radically. The present study investigated with real-time PCR whether these different ligation methods have any influence on the performance of the probes. Sensitivity and the specificity of the padlock probes (PLPs) with the ligation protocol with the best performance were also tested and the selected method was initially validated in a laboratory exchange study.</p> <p>Results</p> <p>Of the ligation protocols tested in this study, the best results were obtained with the PPLMD I and PPLMD II protocols and no consistent differences between these two protocols were observed. Both protocols are based on padlock probe ligation combined with microarray detection. Twenty PLPs were tested for specificity and the best probes were subjected to further evaluation. Up to 13 targets were detected specifically and simultaneously. During the interlaboratory exchange study similar results were achieved by the two participating institutes (NIB, Slovenia, and RIKILT, the Netherlands).</p> <p>Conclusions</p> <p>From the comparison of ligation protocols it can be concluded that two protocols perform equally well on the basis of the selected set of PLPs. Using the most ideal parameters the multiplicity of one of the methods was tested and 13 targets were successfully and specifically detected. In the interlaboratory exchange study it was shown that the selected method meets the 0.1% sensitivity criterion. The present study thus shows that specific and sensitive multidetection of GMO targets is now feasible.</p
Selection of Reference Genes for Transcriptional Analysis of Edible Tubers of Potato (Solanum tuberosum L.)
Potato (Solanum tuberosum) yield has increased dramatically over the last 50 years and this has been achieved by a combination of improved agronomy and biotechnology efforts. Gene studies are taking place to improve new qualities and develop new cultivars. Reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) is a bench-marking analytical tool for gene expression analysis, but its accuracy is highly dependent on a reliable normalization strategy of an invariant reference genes. For this reason, the goal of this work was to select and validate reference genes for transcriptional analysis of edible tubers of potato. To do so, RT-qPCR primers were designed for ten genes with relatively stable expression in potato tubers as observed in RNA-Seq experiments. Primers were designed across exon boundaries to avoid genomic DNA contamination. Differences were observed in the ranking of candidate genes identified by geNorm, NormFinder and BestKeeper algorithms. The ranks determined by geNorm and NormFinder were very similar and for all samples the most stable candidates were C2, exocyst complex component sec3 (SEC3) and ATCUL3/ ATCUL3A/CUL3/CUL3A (CUL3A). According to BestKeeper, the importin alpha and ubiquitin-associated/ts-n genes were the most stable. Three genes were selected as reference genes for potato edible tubers in RT-qPCR studies. The first one, called C2, was selected in common by NormFinder and geNorm, the second one is SEC3, selected by NormFinder, and the third one is CUL3A, selected by geNorm. Appropriate reference genes identified in this work will help to improve the accuracy of gene expression quantification analyses by taking into account differences that may be observed in RNA quality or reverse transcription efficiency across the samples
Risk of breast cancer in women after a salivary gland carcinoma or pleomorphic adenoma in the Netherlands
Salivary and mammary gland tumors show morphological similarities and share various characteristics, including frequent overexpression of hormone receptors and female preponderance. Although this may suggest a common etiology, it remains unclear whether patients with a salivary gland tumor carry an increased risk of breast cancer (BC). Our purpose was to determine the risk of BC in women diagnosed with salivary gland carcinoma (SGC) or pleomorphic adenoma (SGPA). BC incidence (invasive and in situ) was assessed in two nationwide cohorts: one comprising 1567 women diagnosed with SGC and one with 2083 women with SGPA. BC incidence was compared with general population rates using standardized incidence ratio (SIR). BC risk was assessed according to age at SGC/SGPA diagnosis, follow-up time and (for SGC patients) histological subtype. The mean follow-up was 7.0 years after SGC and 9.9 after SGPA diagnosis. During follow-up, 52 patients with SGC and 74 patients with SGPA developed BC. The median time to BC was 6 years after SGC and 7 after SGPA. The cumulative risk at 10 years of follow-up was 3.1% after SGC and 3.5% after SGPA (95% Confidence Interval (95%CI) 2.1%-4.7% and 2.6%-4.6%, respectively). BC incidence was 1.59 times (95%CI 1.19-2.09) higher in the SGC-cohort than expected based on incidence rates in the general population. SGPA-patients showed a 1.48 times (95%CI 1.16-1.86) higher incidence. Women with SGC or SGPA have a slightly increased risk of BC. The magnitude of risk justifies raising awareness, but is no reason for BC screening
Heterogeneity of atmospheric ammonia at the landscape scale and consequences for environmental impact assessment
We examined the consequences of the spatial heterogeneity of atmospheric ammonia (NH3) by measuring and modelling NH3 concentrations and deposition at 25 m grid resolution for a rural landscape containing intensive poultry farming, agricultural grassland, woodland and moorland. The emission pattern gave rise to a high spatial variability of modelled mean annual NH3 concentrations and dry deposition. Largest impacts were predicted for woodland patches located within the agricultural area, while larger moorland areas were at low risk, due to atmospheric dispersion, prevailing wind direction and low NH3 background. These high resolution spatial details are lost in national scale estimates at 1 km resolution due to less detailed emission input maps. The results demonstrate how the spatial arrangement of sources and sinks is critical to defining the NH3 risk to semi-natural ecosystems. These spatial relationships provide the foundation for local spatial planning approaches to reduce environmental impacts of atmospheric NH3
Social and Economic Challenges of Implementing Sustainable Materials on Buildings in Kuwait
Many factors affect attaining the required credits for LEED materials and Many factors affect attaining the required credits for LEED materials and
resources (MR) section. There are disadvantages in obtaining credits and LEED
certifying an existing building in Kuwait to become a sustainable green building. LEED
is still relatively new in Kuwait and the Gulf region, therefore, when certifying an
existing governmental building, difficultly is faced with obtaining complete building
owners, building upper management and occupant cooperation. This raises challenges
when requiring cooperation from building occupants and cleaning staff for the solid
waste management credits which require dedication to reduce the amount of waste going
to landfills and incinerating facilities. The mindset of the contractor and subcontractor
has to change to gain full understanding and cooperation in the waste management of
construction materials when constructing new buildings and performing facility
alterations on site. The selection of sustainable materials is more challenging as many
materials are not available in Kuwait and the surrounding Gulf countries. Transportation
from aboard should be decreased as much as possible to reduce cost as well as decreasing
negative environmental impacts. Green certified materials are more expensive, therefore
decision maker have to be willing to pay the extra cost.
This paper discusses the challenges faced by KISR team as a consultancy body to
certify an existing building according to LEED rating system from the material and
resources aspect. It discusses the acceptance of the building owners, building upper
management and the building occupants to this change and their understanding and
cooperation. Many materials for MR credits 2 and 3 were found difficult to be obtained in
Kuwait and the surrounding gulf region. Some materials were found to be available in the
resources (MR) section. There are disadvantages in obtaining credits and LEED
certifying an existing building in Kuwait to become a sustainable green building. LEED
is still relatively new in Kuwait and the Gulf region, therefore, when certifying an
existing governmental building, difficultly is faced with obtaining complete building
owners, building upper management and occupant cooperation. This raises challenges
when requiring cooperation from building occupants and cleaning staff for the solid
waste management credits which require dedication to reduce the amount of waste going
to landfills and incinerating facilities. The mindset of the contractor and subcontractor
has to change to gain full understanding and cooperation in the waste management of
construction materials when constructing new buildings and performing facility
alterations on site. The selection of sustainable materials is more challenging as many
materials are not available in Kuwait and the surrounding Gulf countries. Transportation
from aboard should be decreased as much as possible to reduce cost as well as decreasing
negative environmental impacts. Green certified materials are more expensive, therefore
decision maker have to be willing to pay the extra cost.
This paper discusses the challenges faced by KISR team as a consultancy body to
certify an existing building according to LEED rating system from the material and
resources aspect. It discusses the acceptance of the building owners, building upper
management and the building occupants to this change and their understanding and
cooperation. Many materials for MR credits 2 and 3 were found difficult to be obtained in
Kuwait and the surrounding gulf region. Some materials were found to be available in th
Development of a multiplex DNA-based traceability tool for crop plant materials
The authenticity of food is of increasing importance for producers, retailers and consumers. All groups benefit from the correct labelling of the contents of food products. Producers and retailers want to guarantee the origin of their products and check for adulteration with cheaper or inferior ingredients. Consumers are also more demanding about the origin of their food for various socioeconomic reasons. In contrast to this increasing demand, correct labelling has become much more complex because of global transportation networks of raw materials and processed food products. Within the European integrated research project ‘Tracing the origin of food’ (TRACE), a DNA-based multiplex detection tool was developed—the padlock probe ligation and microarray detection (PPLMD) tool. In this paper, this method is extended to a 15-plex traceability tool with a focus on products of commercial importance such as the emmer wheat Farro della Garfagnana (FdG) and Basmati rice. The specificity of 14 plant-related padlock probes was determined and initially validated in mixtures comprising seven or nine plant species/varieties. One nucleotide difference in target sequence was sufficient for the distinction between the presence or absence of a specific target. At least 5% FdG or Basmati rice was detected in mixtures with cheaper bread wheat or non-fragrant rice, respectively. The results suggested that even lower levels of (un-)intentional adulteration could be detected. PPLMD has been shown to be a useful tool for the detection of fraudulent/intentional admixtures in premium foods and is ready for the monitoring of correct labelling of premium foods worldwide
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