4,202 research outputs found
'Bad teacher? Using films as texts when teaching business ethics: Exploring the issues'
The contemporary teaching of business ethics necessarily involves the recognition that texts, materials and modes of assessment ought to be rendered appealing to students, while at the same time ensuring the quality of teaching. Prima facie the use of film can be seen as a way to address this dilemma: Students may be attracted to the âdeliveryâ of course content through the medium of film as opposed to, for example, standard lecture format, participation in online activities or, at a stretch, reading and writing. An alternative scenario can also be envisioned where the use of film in teaching business ethics is bad professional practice, pandering to both the requirement for positive assessments from students and for technological change. This paper discusses these issues by critically examining the films recommended by a contemporary business ethics text, Crane and Matten (2010). We identify significant problems with the use of two films, The Corporation (2005) and Michael Clayton (2007). Against our own criticisms of these two texts, the paper then focuses upon Ken Loachâs (2007) film Itâs a Free World, arguing that it is a useful text for the illustration of what students, more often than not, regard as the clichĂ©d issue of unskilled foreign wage labourers being exploited in âadvancedâ western economies. Despite the considerable virtues of Loachâs particular text, we argue that any recourse to film as an alternative method of examining a range of issues in business ethics has to be treated with caution
Illuminating Choices for Library Prep: A Comparison of Library Preparation Methods for Whole Genome Sequencing of Cryptococcus neoformans Using Illumina HiSeq.
The industry of next-generation sequencing is constantly evolving, with novel library preparation methods and new sequencing machines being released by the major sequencing technology companies annually. The Illumina TruSeq v2 library preparation method was the most widely used kit and the market leader; however, it has now been discontinued, and in 2013 was replaced by the TruSeq Nano and TruSeq PCR-free methods, leaving a gap in knowledge regarding which is the most appropriate library preparation method to use. Here, we used isolates from the pathogenic fungi Cryptococcus neoformans var. grubii and sequenced them using the existing TruSeq DNA v2 kit (Illumina), along with two new kits: the TruSeq Nano DNA kit (Illumina) and the NEBNext Ultra DNA kit (New England Biolabs) to provide a comparison. Compared to the original TruSeq DNA v2 kit, both newer kits gave equivalent or better sequencing data, with increased coverage. When comparing the two newer kits, we found little difference in cost and workflow, with the NEBNext Ultra both slightly cheaper and faster than the TruSeq Nano. However, the quality of data generated using the TruSeq Nano DNA kit was superior due to higher coverage at regions of low GC content, and more SNPs identified. Researchers should therefore evaluate their resources and the type of application (and hence data quality) being considered when ultimately deciding on which library prep method to use
Three "universal" mesoscopic Josephson effects
1. Introduction
2. Supercurrent from Excitation Spectrum
3. Excitation Spectrum from Scattering Matrix
4. Short-Junction Limit
5. Universal Josephson Effects
5.1 Quantum Point Contact
5.2 Quantum Dot
5.3 Disordered Point Contact (Average supercurrent, Supercurrent
fluctuations)Comment: 21 pages, 2 figures; legacy revie
Experimental evaluation of the extractability of Fe-bound organic carbon in sediments as a function of carboxyl content
The majority of organic carbon (OC) burial in marine sediments occurs on continental shelves, of which an estimated 10â20% is associated with reactive iron (FeR). The association of OC with FeR (OC-FeR) is thought to facilitate preservation of organic matter (OM) in sediments and therefore represents an important carbon sink. The citrate-bicarbonate-dithionite (CBD) method is used to quantify OC-FeR in marine sediments by reductively dissolving FeR, thereby releasing bound OC. While the CBD method is widely used, it may be less efficient at measuring OC-FeR than currently thought, due to the incomplete reduction of FeR, resulting from the neutral pH conditions required to prevent OM hydrolysis. Additionally, the typical range of values reported for OC-FeR in marine sediments is narrow, despite variation in OM and FeR inputs, OM source types and chemical compositions. This suggests a limitation exists on the amount of OC that can become associated with FeR, and/or that the CBD method is limited in the OC-FeR that it is able to quantify. In assessing the efficiency of the CBD method, we aimed to understand whether methodological errors or (mis)interpretation of these extraction results may contribute to the apparent limitation on OC-FeR values. Here, we synthesised OC-FeR composites with a known FeR phase and known OM moieties, varying in carboxyl content, at neutral pH. These were spiked into OC-free marine sediment, and subject to a CBD extraction to investigate i) the efficiency of CBD for OC extraction; ii) the efficiency of CBD for FeR extraction; ii) how the OC moiety affects the physical parameters of associated FeR minerals; and iii) the impact of OM moiety on OC and Fe release. We show that the CBD method results in only partial dissolution of the most susceptible FeR phase (ferrihydrite) and therefore incomplete removal of bound OC. While as little as ~20% of Fe is released from OC-free ferrihydrite, structural disorder of the mineral phase increases with the inclusion of more OC, resulting in greater losses of up to 62% Fe for carboxyl rich OC-FeR complexes. In addition, our results show that the NaCl control step performed in the CBD method is capable of removing weakly bound OC from FeR, such that inclusion of this OC in the total OC-FeR fraction may increase marine sediments OC-FeR estimates by ~33%. Finally, we suggest that the structure of OC involved in OC-FeR binding can affect quantification of the OC-FeR pool. Our results have important implications for assessing the FeR bound OC fraction in marine sediments and the fate of this OC in the global carbon cycle
Technical note: Uncovering the influence of methodological variations on the extractability of iron-bound organic carbon
Association of organic carbon (OC) with reactive iron (FeR) represents an important mechanism by which OC is protected against remineralisation in soils and marine sediments. Recent studies indicate that the molecular structure of organic compounds and/or the identity of associated FeR phases exert a control on the ability of an OCâFeR complex to be extracted by the citrateâbicarbonateâdithionite (CBD) method. However, many variations of the CBD extraction are used, and these are often uncalibrated to each other, rendering comparisons of OCâFeR values extracted via the different methods impossible. Here, we created synthetic ferrihydrite samples coprecipitated with simple organic structures and subjected these to modifications of the most common CBD method. We altered some of the method parameters (reagent concentration, time of the extraction and sample preparation methods) and measured FeR recovery to determine which (if any) modifications affected the release of FeR from the synthetic sample. We provide an assessment of the reducing capacity of Na dithionite in the CBD method (the amount of Fe reduced by a fixed amount of dithionite) and find that the concentration of dithionite deployed can limit OCâFeR extractability for sediments with a high FeR content. Additionally, we show that extending the length of any CBD extraction offers no benefit in removing FeR. Moreover, we demonstrate that for synthetic OCâFeR samples dominated by ferrihydrite, freeze-drying samples can significantly reduce OCâFeR extractability; this appears to be less of an issue for natural marine sediments where natural ageing mechanisms may mimic the freeze-drying process for more stable Fe phases. While our study is not an all-inclusive method comparison and is not aimed at delivering the âperfectâ extraction setup, our findings provide a collected summary of critical factors which influence the efficiency of the CBD extraction for OCâFeR. As such, we provide a platform from which OCâFeR values obtained under different methods can be interpreted and future studies of sediment carbon cycling can build upon
Learning environment associated with use of mixed mode delivery model among secondary business studies students in Singapore
At many teacher education institutes around the world, preservice teachers are empowered to use pedagogical tools and strategies that engage their students. We used a modified version of the Constructivist Learning Environment Survey (CLES) to evaluate the effectiveness of a pedagogical model known as the Mixed Mode Delivery (MMD) model in terms of the CLESâs five scales of personal relevance, uncertainty, critical voice, shared control and negotiation. Comparisons were made between 2,216 secondary school students taught by the preservice teachers in an MMD group and 991 students in a control group in terms of the relative magnitudes of the gap between the actual and preferred learning environment in studentsâ school classrooms. The findings supported the positive impact of using MMD in terms of studentsâ perceptions of their classroom environments for all CLES scales
Effectiveness of student response systems in terms of learning environment, attitudes and achievement
In order to investigate the effectiveness of using Student Response Systems (SRS) among grade 7 and 8 science students in New York, the How Do You Feel About This Class? (HDYFATC) questionnaire was administered to 1097 students (532 students did use SRS and 565 students who did not use SRS). Data analyses attested to the sound factorial validity and internal consistency reliability of the HDYFATC, as well as its ability to differentiate between the perceptions of students in different classrooms. Very large differences between users and non-users of SRS, ranging from 1.17 to 2.45 standard deviations for various learning environment scales, attitudes and achievement, supported the efficacy of using SRS
Mathematizing Darwin
Ernst Mayr called the first part of the evolutionary synthesis the âFisherian synthesisâ on account of the dominant role played by R.A. Fisher in forging a mathematical theory of natural selection together with J.B.S. Haldane and Sewall Wright in the decade 1922â1932. It is here argued that Fisherâs contribution relied on a close reading of Darwinâs work to a much greater extent than did the contributions of Haldane and Wright, that it was synthetic in contrast to their analytic approach and that it was greatly influenced by his friendship with the Darwin family, particularly with Charlesâs son Leonard
Field-study science classrooms as positive and enjoyable learning environments
We investigated differences between field-study classrooms and traditional science classrooms in terms of the learning environment and studentsâ attitudes to science, as well as the differential effectiveness of field-study classrooms for students differing in sex and English proficiency. A modified version of selected scales from the What Is Happening In this Class? questionnaire was used to assess the learning environment, whereas studentsâ attitudes were assessed with a shortened version of a scale from the Test of Science Related Attitudes. A sample of 765 grade 5 students from 17 schools responded to the learning environment and attitude scales in terms of both their traditional science classrooms and classrooms at a field-study centre in Florida. Large effect sizes supported the effectiveness of the field-studies classroom in terms of both the learning environment and student attitudes. Relative to the home school science class, the field-study class was considerably more effective for students with limited English proficiency than for native English speakers
Clinical biological and genetic heterogeneity of the inborn errors of pulmonary surfactant metabolism
Pulmonary surfactant is a multimolecular complex located at the air-water interface within the alveolus to which a range of physical (surface-active properties) and immune functions has been assigned. This complex consists of a surface-active lipid layer (consisting mainly of phospholipids), and of an aqueous subphase. From discrete surfactant sub-fractions one can isolate strongly hydrophobic surf acta nt proteins B (SP-B) and C (SP-C) as well as collectins SP-A and SP-D, which were shown to have specific structural, metabolic, or immune properties. Inborn or acquired abnormalities of the surfactant, qualitative or quantitative in nature, account for a number of human diseases. Beside hyaline membrane disease of the preterm neonate, a cluster of hereditary or acquired lung diseases has been characterized by periodic acid-Schiff-positive material filling the alveoli. From this heterogeneous nosologic group, at least two discrete entities presently emerge. The first is the SP-B deficiency, in which an essentially proteinaceous material is stored within the alveoli, and which represents an autosomal recessive Mendelian entity linked to the SFTPB gene (MIM 1786640). The disease usually generally entails neonatal respiratory distress with rapid fatal outcome, although partial or transient deficiencies have also been observed. The second is alveolar proteinosis, characterized by the storage of a mixed protein and lipid material, which constitutes a relatively heterogeneous clinical and biological syndrome, especially with regard to age at onset (from the neonate through to adulthood) as well as the severity of associated signs. Murine models, with a targeted mutation of the gene encoding granulocyte macrophage colony-stimulating factor (GM-CSF) (Csfgm) or the beta subunit of its receptor (II3rb1) support the hypothesis of an abnormality of surfactant turnover in which the alveolar macrophage is a key player. Apart from SP-B deficiency, in which a near-consensus diagnostic chart can be designed, the ascertainment of other abnormalities of surfactant metabolism is not straightforward. The disentanglement of this disease cluster is however essential to propose specific therapeutic procedures: repeated broncho-alveolar ravages, GM-CSF replacement, bone marrow grafting or lung transplantation
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