Profiling human breast epithelial cells using single cell RNA sequencing identifies cell diversity.

Breast cancer arises from breast epithelial cells that acquire genetic alterations leading to subsequent loss of tissue homeostasis. Several distinct epithelial subpopulations have been proposed, but complete understanding of the spectrum of heterogeneity and differentiation hierarchy in the human breast remains elusive. Here, we use single-cell mRNA sequencing (scRNAseq) to profile the transcriptomes of 25,790 primary human breast epithelial cells isolated from reduction mammoplasties of seven individuals. Unbiased clustering analysis reveals the existence of three distinct epithelial cell populations, one basal and two luminal cell types, which we identify as secretory L1- and hormone-responsive L2-type cells. Pseudotemporal reconstruction of differentiation trajectories produces one continuous lineage hierarchy that closely connects the basal lineage to the two differentiated luminal branches. Our comprehensive cell atlas provides insights into the cellular blueprint of the human breast epithelium and will form the foundation to understand how the system goes awry during breast cancer

Puffins, Pigs, Cod, and Barley: Palaeoeconomy at Undir Junkarinsfløtti, Sandoy, Faroe Islands

This paper reports on the zooarchaeological and archaeobotanical remains from the initial season of excavations at the Norse period site at Undir Junkarinsfløtti in the Faroe islands. These remains represent the first zooarchaeological analysis undertaken for the Faroes and only the third archaeobotanical assemblage published from the islands. The excavated deposits are described and the key findings from the palaeoenvironmental remains highlighted within the context of the wider North Atlantic environmental archaeology of the Norse period

The presence of peat and variation in tree species composition are under different hydrological controls in Amazonian wetland forests

This research was funded by the Gordon and Betty Moore Foundation, through grant #5349 ‘Monitoring protected areas in Peru to increase forest resilience to climate change’, and NERC standard grant ‘Carbon Storage in Amazonian Peatlands: Distribution and Dynamics’(NE/R000751/1).The peat-forming wetland forests of Amazonia are characterised by high below-carbon stocks and supply fruit, fibres and timber to local communities. Predicting the future of these ecosystem services requires understanding how hydrological conditions are related to tree species composition and the presence, or absence, of peat. Here, we use continuous measurements of water table depth over 2.5 years and manual measurements of pore-water pH and electrical conductivity to understand the ecohydrological controls of these variables across the large peatland complex in northern Peruvian Amazonia. Measurements were taken in permanent forest plots in four palm swamps, four seasonally flooded forests and four peatland pole forests. All trees ≥10 cm diameter were also measured and identified in the plots to assess floristic composition. Peat occurs in eight of these twelve sites; three seasonally flooded forests and one palm swamp are not associated with peat. Variation in tree species composition among forest types was linked to high flood levels (maximum flooding height) and pH: seasonally flooded forests experience high flood levels (up to 3.66 m from the ground surface) and have high pH values (6?7), palm swamps have intermediate flood levels (up to 1.34 m) and peatland pole forests experience shallow flooding (up to 0.28 m) and have low pH (4). In contrast, the presence of peat was linked to variation in maximum water table depth (ie the depth to which the water table drops below the ground surface). Surface peat is found in all forest types where maximum water table depth does not fall >0.55 m below the ground surface at any time. Peat formation and variation in tree species composition therefore have different ecohydrological controls. Predicted increases in the frequency and strength of flooding events may alter patterns of tree species composition, whereas increases in drought severity and declines in minimum river levels may pose a greater risk to the belowground carbon stores of these peatland ecosystems.Publisher PDFPeer reviewe

Climatic control on Icelandic volcanic activity during the mid-Holocene

Human-induced climate change is causing rapid melting of ice in many volcanically active regions. Over glacial-interglacial time scales changes in surface loading exerted by large variations in glacier size affect the rates of volcanic activity. Numerical models suggest that smaller changes in ice volume over shorter time scales may also influence rates of mantle melt generation. However, this effect has not been verified in the geological record. Furthermore, the time lag between climatic forcing and a resultant change in the frequency of volcanic eruptions is unknown. We present empirical evidence that the frequency of volcanic eruptions in Iceland was affected by glacial extent, modulated by climate, on multicentennial time scales during the Holocene. We examine the frequency of volcanic ash deposition over northern Europe and compare this with Icelandic eruptions. We identify a period of markedly reduced volcanic activity centered on 5.5–4.5 ka that was preceded by a major change in atmospheric circulation patterns, expressed in the North Atlantic as a deepening of the Icelandic Low, favoring glacial advance on Iceland. We calculate an apparent time lag of ∼600 yr between the climate event and change in eruption frequency. Given the time lag identified here, increase in volcanic eruptions due to ongoing deglaciation since the end of the Little Ice Age may not become apparent for hundreds of years

An evaluation of pharmacology curricula in Australian science and health-related degree programs

Background: Pharmacology is a biomedical discipline taught in basic science and professional degree programs. In order to provide information that would facilitate pharmacology curricula to be refined and developed, and approaches to teaching to be updated, a national survey was undertaken in Australia that investigated pharmacology course content, teaching and summative assessment methods. Methods: Twenty-two institutions participated in a purpose-built online questionnaire, which enabled an evaluation of 147 courses taught in 10 different degrees. To enable comparison, degrees were grouped into four major degree programs, namely science, pharmacy, medicine and nursing. The pharmacology content was then classified into 16 lecture themes, with 2-21 lecture topics identified per theme. The resultant data were analysed for similarities and differences in pharmacology curricula across the degree programs. Results: While all lecture themes were taught across degree programs, curriculum content differed with respect to the breadth and hours of coverage. Overall, lecture themes were taught most broadly in medicine and with greatest coverage in pharmacy. Reflecting a more traditional approach, lectures were a dominant teaching method (at least 90% of courses). Sixty-three percent of science courses provided practical classes but such sessions occurred much less frequently in other degree programs, while tutorials were much more common in pharmacy degree programs (70%). Notably, problem-based learning was common across medical programs. Considerable diversity was found in the types of summative assessment tasks employed. In science courses the most common form of in-semester assessment was practical reports, whereas in other programs pen-and-paper quizzes predominated. End-of-semester assessment contributed 50-80% to overall assessment across degree programs. Conclusion: The similarity in lecture themes taught across the four different degree programs shows that common knowledge- and competency-based learning outcomes can be defined for pharmacology. The authors contend that it is the differences in breadth and coverage of material for each lecture theme, and the differing teaching modes and assessment that characterise particular degree programs. Adoption of pharmacology knowledge-based learning outcomes that could be tailored to suit individual degree programs would better facilitate the sharing of expertise and teaching practice than the current model where pharmacology curricula are degree-specific.Hilary Lloyd, Tina Hinton, Shane Bullock, Anna-Marie Babey, Elizabeth Davis, Lynette Fernandes, Joanne Hart, Ian Musgrave and James Zioga

Antipredatory Function of Head Shape for Vipers and Their Mimics

Most research into the adaptive significance of warning signals has focused on the colouration and patterns of prey animals. However, behaviour, odour and body shape can also have signal functions and thereby reduce predators' willingness to attack defended prey. European vipers all have a distinctive triangular head shape; and they are all venomous. Several non-venomous snakes, including the subfamily Natricinae, commonly flatten their heads (also known as head triangulation) when disturbed. The adaptive significance of this potential behavioural mimicry has never been investigated

Climatic control on Icelandic volcanic activity during the mid-Holocene

Human-induced climate change is causing rapid melting of ice in many volcanically active regions. Over glacial-interglacial time scales changes in surface loading exerted by large variations in glacier size affect the rates of volcanic activity. Numerical models suggest that smaller changes in ice volume over shorter time scales may also influence rates of mantle melt generation. However, this effect has not been verified in the geological record. Furthermore, the time lag between climatic forcing and a resultant change in the frequency of volcanic eruptions is unknown. We present empirical evidence that the frequency of volcanic eruptions in Iceland was affected by glacial extent, modulated by climate, on multicentennial time scales during the Holocene. We examine the frequency of volcanic ash deposition over northern Europe and compare this with Icelandic eruptions. We identify a period of markedly reduced volcanic activity centered on 5.5–4.5 ka that was preceded by a major change in atmospheric circulation patterns, expressed in the North Atlantic as a deepening of the Icelandic Low, favoring glacial advance on Iceland. We calculate an apparent time lag of ∼600 yr between the climate event and change in eruption frequency. Given the time lag identified here, increase in volcanic eruptions due to ongoing deglaciation since the end of the Little Ice Age may not become apparent for hundreds of years