A multinational, multi-institutional study of assessment of programming skills of first-year CS students

In computer science, an expected outcome of a student's education is programming skill. This working group investigated the programming competency students have as they complete their first one or two courses in computer science. In order to explore options for assessing students, the working group developed a trial assessment of whether students can program. The underlying goal of this work was to initiate dialog in the Computer Science community on how to develop these types of assessments. Several universities participated in our trial assessment and the disappointing results suggest that many students do not know how to program at the conclusion of their introductory courses. For a combined sample of 216 students from four universities, the average score was 22.89 out of 110 points on the general evaluation criteria developed for this study. From this trial assessment we developed a framework of expectations for first-year courses and suggestions for further work to develop more comprehensive assessments

Consecutive tests, by the fractional method of gastric analysis, in seventy-five cases presenting gastric symptoms

VOLUME I: I . Introduction • II . The Physiology o f the Stomach • III . Various Gastric Secretory and Gastric Motility Tests • IV. The Technique of Fractional Analysis • V. The Features of the Fractional Analysis Chart • VI. Views upon the Practical Value of the Fractional Method of Gastric Analysis • VII. The Analysis of the Charts obtained from the present series of cases • VIII. Summary • IX. Conclusion • • VOLUME II: X. Appendi

Factors affecting the availability of invertebrate food for the chough, Pyrrhocorax pyrrhocorax L

Most of the fieldwork for this study was conducted on the island of Islay, in the Inner Hebrides, the stronghold of the chough, Pyrrhocorax pyrrhocorax L., in Scotland. The aims of this study were to provide baseline data on the phenology of potential invertebrate foods of the chough, and to provide a greater understanding of the factors affecting these invertebrate populations. The literature concerning (a) the chough in Britain and its feeding ecology, (b) the invertebrate fauna of pasture, (c) the invertebrates associated with cow dung, (d) ivermectin and its effect on the invertebrate fauna associated with cattle dung, and (e) the multivariate analysis methods used in this study, is reviewed. An area of heather moorland and four pastures were selected on Islay. Invertebrates were collected from these sites between January 1988 and November 1989 using pitfall traps, and by sampling soil and cow pats. The data obtained was analysed using two multivariate analysis methods -Two-Way-Indicator-Species- Analysis (TWINSPAN) and Detrended Correspondence Analysis (DECORANA). Information on 62 surface-active taxa was obtained from pitfall trapping. Although seasonal taxa assemblages were recognized, the distribution of the invertebrate communities was primarily related to soil moisture content. Grazing intensity and seasonality were also important factors determining the composition of the invertebrate fauna at each site. The taxa active during the summer and winter at the two sand grassland sites, did not appear to differ as markedly as at the other sites sampled. Figures showing the seasonal activity of some of the frequently occurring taxa at each site considered potential chough prey items are provided. Surface-active potential chough food items were present, at all the sites investigated, throughout the year. Soil-sampling provided information on 34 taxa. As with the surface-active fauna, the primary factor influencing the soil fauna was soil moisture content. The time of year was also an important factor governing the soil fauna composition, with the majority of taxa occurring in low numbers during the summer months at all the sites sampled. Figures indicating the seasonal occurrences of some of the taxa considered potential chough prey items at each site are provided. Soil did not appear to be a good source of potential prey items for the chough during the summer months, although, as a result of seasonal increases in size, certain taxa, e.g. Tipulidae larvae, may have been more 'worthwhile' prey items at this time of year than at any other. Information on 54 taxa was obtained from sampling cow dung. Seasonality and age of the dung were very important in determining the composition of the dung fauna. The seasonal variations in the fauna associated with the cow pats are described. Potential chough prey items were associated with cow dung, in any stage of decay, throughout most of the year. Only during the period from October/November to January did there appear to be a lack of suitably sized potential prey items in the dung. The 'summer' months, when fresh dung contained large numbers of beetle adults and developing fly larvae, and late autumn, when pats deposited during the summer months are old enough for the large numbers of Aphodius spp. larvae present to have attained a reasonable size, were considered to be the times at which cow dung presented the best feeding opportunities for the chough. Fifty taxa were identified in samples of chough faeces. Multivariate analysis of these data indicated that the seasonal availability of prey items was the most important factor influencing chough diet throughout the year. Soil-dwelling Tipulidae (January to July) and Bibionidae (January to April) larvae, dung-associated insects (during the spring, and late summer and autumn), and surface-active insects (during the summer) were important invertebrate components of the diet. Cereal grains were extremely important supplementary food items during the early winter months, when invertebrate availability was low. An experiment was conducted at the College to investigate the effects on the dung fauna of spiking cow dung with 2.0, 1.0, or 0.5 mg/kg dung of ivermectin. Pats were placed on pasture between May and September 1988. The pats were lifted, and the soil beneath sampled, after 15 to 90 days exposure. A total of 65 taxa were identified. These data were analysed using TWINSPAN, DECORANA and Canonical Correspondence Analysis (CANOCO). The major factors determining the invertebrate fauna of the pats were length of exposure, exposure date, and ivermectin presence/absence. Ivermectin markedly affected the fauna associated with the pats. Pats exposed in June and August degraded faster than those exposed in May or September. In June, the ivermectin-treated pats degraded significantly slower than the control pats. An attempt to extract ivermectin from cow dung for analysis by high-performance liquid chromatography is described. This proved unsuccessful and the reasons for this failure, and possible improvements, are discussed. The main conclusions of this study are: (1) that Tipulidae larvae are extremely important components of the chough's diet on Islay, and that the climatic conditions of the island favour these insects; (2) livestock farming on Islay, especially the out-wintering of cattle, provides essential feeding opportunities for the chough, as, (a) gazing animals produce the short sward preferred by the chough as a feeding habitat, (b) large numbers of insects are associated with the dung of these animals, and (c) supplementary feed provided for the cattle in winter also provides an essential alternative food source for the chough at a critical time; (3) the chough's preference on Islay for feeding in sandy, coastal pasture is due to the fact that these sites, (a) contain a variety of suitable invertebrate prey items throughout most of the year, (b) are normally intensively grazed and so contain large amounts of dung with its associated fauna, and (c) are used for out-wintering cattle and therefore cereal grains can be found there; (4) treating cattle with ivermectin could have an adverse effect on the chough as it reduces the number and variety of invertebrates associated with the dung, an important food source for the birds, especially in spring and autumn

Improving the science-policy dialogue to meet the challenges of biodiversity conservation: having conversations rather than talking at one-another

A better, more effective dialogue is needed between biodiversity science and policy to underpin the sustainable use and conservation of biodiversity. Many initiatives exist to improve communication, but these largely conform to a ‘linear’ or technocratic model of communication in which scientific “facts” are transmitted directly to policy advisers to “solve problems”. While this model can help start a dialogue, it is, on its own, insufficient, as decision taking is complex, iterative and often selective in the information used. Here, we draw on the literature, interviews and a workshop with individuals working at the interface between biodiversity science and government policy development to present practical recommendations aimed at individuals, teams, organisations and funders. Building on these recommendations, we stress the need to: (a) frame research and policy jointly; (b) promote inter- and trans-disciplinary research and “multi-domain” working groups that include both scientists and policy makers from various fields and sectors; (c) put in place structures and incentive schemes that support interactive dialogue in the long-term. These are changes that are needed in light of continuing loss of biodiversity and its consequences for societal dependence on and benefits from nature

Mapping the transcriptional dynamics of the endothelium during human embryonic stem cell differentiation and cardiac development using single cell RNA sequencing

The endothelium comprises the luminal surface of all blood and lymphatic vessels and is known to first emerge from mesodermal precursors in a process known as vasculogenesis. Following formation of a primitive vascular plexus, the endothelium rapidly expands by angiogenesis and undergoes specification into arterial, venous, capillary, lymphatic, and haemogenic subtypes. Additionally, in response to intrinsic and tissue specific cues, the endothelium undergoes further specialisation to meet the individual requirements of the surrounding tissue. However, despite improving understanding of the sequence of events occurring during endothelial cell (EC) development, the transcriptional control underlying these processes remains largely uncharacterised. The differentiation of human embryonic stem cells (hESC) to endothelium offers an appropriate model to study the transcriptional control of endothelial differentiation in vitro. In this study I applied high throughput single cell RNA sequencing (scRNA-seq) to an efficient 8-day hESC endothelial differentiation protocol, collecting cells at days 0, 4, 6, and 8. Flow cytometric analysis of day 8 cells revealed a population in which 66% of cells co-expressed endothelial markers CD31 and CD144. Analysis of scRNA-seq data from day 0 and 4 revealed homogeneous populations defined by expression of pluripotent and lateral mesoderm markers, respectively. In contrast, scRNA-seq analysis of cells collected at days 6 and 8 show the emergence of distinct endothelial and mesenchymal populations. Repeating scRNA-seq analysis of hESC-endothelial differentiation with a second hESC line as well as using an alternative differentiation protocol revealed highly comparable transcriptional signatures of endothelial differentiation. However, comparison of data from hESC derived endothelial cells (hESC-EC) to equivalent scRNA-seq data from cultured and freshly isolated human organ-specific endothelial cells, demonstrated a clear distinction in their transcriptional state, thus highlighting the likely unspecified nature of hESC-EC. Following on from these findings, I then sought to determine if mapping the dynamic transcriptional landscape of the endothelium during human cardiac development could be used to identify novel regulators of endothelial maturation and specification. CD31+/CD45- endothelial cells isolated by FACS from heart tissue obtained from 13- and 14-week fetuses were processed for scRNA-seq analysis. Subsequent dimensionality reduction and clustering of data revealed distinct endocardial, capillary, venous, arterial, and lymphatic populations each with a unique transcriptional signature. Application of trajectory inference methods predicted a minor endocardial contribution to the coronary vasculature via a venous population, prior to the subsequent arterial specification of capillary EC. Mapping differentially expressed genes over pseudotime revealed the expression of MECOM to coincide with the onset of arterial specification. In conjunction, gene regulatory network analysis also placed MECOM amongst known regulators of arterial EC specification such as HEY1 and SOX17. Subsequent knockdown of MECOM in arterial-like hESC- EC suggested a function in repressing venous identity in arterial EC. Together these studies provide a comprehensive map of the transcriptional landscape accompanying both hESC-EC differentiation and during human cardiac EC development. Mapping these dynamic processes offers new insight into the mechanisms underlying endothelial development, creating future opportunities for vascular regeneration for ischaemic disease. Lastly, in response to the COVID-19 pandemic I determined the susceptibility of endothelial cells to in-vitro infection with human coronaviruses, including SARS-CoV-2. Despite demonstrating productive infection of endothelial cells by HCoV-229E, a lack of replicative infection was observed by SARS-CoV-2. This was most likely due to an absence of the expression of the SARS-CoV-2 receptor, angiotensin converting enzyme 2 (ACE2)

Transcriptional regulators of arteriovenous identity in the developing mammalian embryo

The complex and hierarchical vascular network of arteries, veins, and capillaries features considerable endothelial heterogeneity, yet the regulatory pathways directing arteriovenous specification, differentiation, and identity are still not fully understood. Recent advances in analysis of endothelial-specific gene-regulatory elements, single-cell RNA sequencing, and cell lineage tracing have both emphasized the importance of transcriptional regulation in this process and shed considerable light on the mechanism and regulation of specification within the endothelium. In this review, we discuss recent advances in our understanding of how endothelial cells acquire arterial and venous identity and the role different transcription factors play in this process

A catalogue of verified and characterized arterial enhancers for key arterial identity genes

The establishment and growth of the arterial endothelium requires the coordinated expression of numerous genes. However, the transcriptional and signalling pathways regulating this process are still not fully established, and only a small number of enhancers for key arterial genes have been characterized. Here, we sought to generate a useful and accessible cohort of arterial enhancers with which to study arterial transcriptional regulation. We combined in silico analysis with transgenic zebrafish and mouse models to find and validate enhancers associated with eight key arterial identity genes (Acvrl1/Alk1, Cxcr4, Cxcl12, Efnb2, Gja4/Cx37, Gja5/Cx40, Nrp1 and Unc5b). This identified a cohort of enhancers able to independently direct robust transcription to arterial ECs within the vasculature. To elucidate the regulatory pathways upstream of arterial gene transcription, we determined the occurrence of common endothelial transcription factor binding motifs, and assessed direct binding of these factors across all arterial enhancers compared to similar assessments of non-arterial-specific enhancers. These results find that binding of SOXF and ETS factors is a shared event across arterial enhancers, but also commonly occurs at pan-endothelial enhancers. Conversely, RBPJ/Notch, MEF2 and FOX binding was over-represented but not ubiquitous at arterial enhancers. We found no shared or arterial-specific signature for canonical WNT-associated TCF/LEF transcription factors, canonical TGFβ/BMP-associated SMAD1/5 and SMAD2, laminar shear stress-associated KLF factors or venous-enriched NR2F2 factors. This cohort of well characterized and in vivo-verified enhancers can now provide a platform for future studies into the interaction of different transcriptional and signalling pathways with arterial gene expression

The production and consumption activities relating to the celebrity artist

This paper considers the impact of the celebrity artist on the associated production and consumption activities. It also considers the role which entrepreneurial marketing plays in helping to create the celebrity artist aura. The artist Thomas Kinkade is used to illustrate how this occurs in practice. Here, authenticity and nostalgia dimensions are also influential factors. Underpinning these relationships are the roles played out by the media, including communication of celebrity artist identity, and the catalysing of its commodification within the celebrity artist brandscape. An enduring celebrity brand results due to the market creation activities of the celebrity artist. A conceptual model is developed which synthesises the factors behind the production and consumption of the celebrity artist which can stimulate further research. This paper provides innovative insight into the world of the celebrity artist by interrogating the market making and shaping devices behind successful production and consumption practices

Evaluating the transcriptional regulators of arterial gene expression via a catalogue of characterized arterial enhancers

The establishment and growth of the arterial endothelium require the coordinated expression of numerous genes. However, regulation of this process is not yet fully understood. Here, we combined in silico analysis with transgenic mice and zebrafish models to characterize arterial-specific enhancers associated with eight key arterial identity genes (Acvrl1/Alk1, Cxcr4, Cxcl12, Efnb2, Gja4/Cx37, Gja5/Cx40, Nrp1, and Unc5b). Next, to elucidate the regulatory pathways upstream of arterial gene transcription, we investigated the transcription factors binding each arterial enhancer compared to a similar assessment of non-arterial endothelial enhancers. These results found that binding of SOXF and ETS factors was a common occurrence at both arterial and pan-endothelial enhancers, suggesting neither are sufficient to direct arterial specificity. Conversely, FOX motifs independent of ETS motifs were over-represented at arterial enhancers. Further, MEF2 and RBPJ binding was enriched but not ubiquitous at arterial enhancers, potentially linked to specific patterns of behaviour within the arterial endothelium. Lastly, there was no shared or arterial-specific signature for WNT-associated TCF/LEF, TGFβ/BMP-associated SMAD1/5 and SMAD2/3, shear stress-associated KLF4, or venous-enriched NR2F2. This cohort of well-characterized and in vivo-verified enhancers can now provide a platform for future studies into the interaction of different transcriptional and signaling pathways with arterial gene expression