1,133 research outputs found
‘Sufurias cannot bring blessings’: change, continuity and resilience in the world of Marakwet pottery, a case from western Kenya
Drawing on fieldwork conducted over multiple seasons between 2012 and 2015, this paper explores aspects of the socio-economic and political history of the Marakwet of Kenya. It does so by focusing on a particular material culture category – pottery – and tracing transformations in its production, use and exchange over several generations from the early twentieth century to the present day. This approach serves to unearth a series of personal and quotidian narratives that not only comprise a unique account of Marakwet’s past, but also shed light on the material consequences of various ongoing processes of infrastructural and economic development. Complementing our previous work on Marakwet farming, landscape and ecological change, we here demonstrate the multiple ways in which change has been dynamically negotiated and enacted throughout the last century via various shifting daily practices. The historical innovations, adaptations and movements that we explore attest to a resilience deeply rooted in Marakwet society that continues to be articulated in the contemporary world
Multiple Equilibria in a Single-Column Model of the Tropical Atmosphere
A single-column model run under the weak temperature gradient approximation,
a parameterization of large-scale dynamics appropriate for the tropical
atmosphere, is shown to have multiple stable equilibria. Under conditions
permitting persistent deep convection, the model has a statistically steady
state in which such convection occurs, as well as an extremely dry state in
which convection does not occur. Which state is reached depends on the initial
moisture profile.Comment: Submitted to Geophysical Research Letter
Small RNA analyses of a ceratobasidium isolate infected with three endornaviruses
Isolates of three endornavirus species were identified co-infecting an unidentified species of Ceratobasidium, itself identified as a symbiont from within the roots of a wild plant of the terrestrial orchid Pterostylis vittata in Western Australia. Isogenic lines of the fungal isolate lacking all three mycoviruses were derived from the virus-infected isolate. To observe how presence of endornaviruses influenced gene expression in the fungal host, we sequenced fungus-derived small RNA species from the virus-infected and virus-free isogenic lines and compared them. The presence of mycoviruses influenced expression of small RNAs. Of the 3272 fungus-derived small RNA species identified, the expression of 9.1% (300 of 3272) of them were up-regulated, and 0.6% (18 of 3272) were down-regulated in the presence of the viruses. Fourteen novel micro-RNA-like RNAs (Cer-milRNAs) were predicted. Gene target prediction of the differentially expressed Cer-milRNAs was quite ambiguous; however, fungal genes involved in transcriptional regulation, catalysis, molecular binding, and metabolic activities such as gene expression, DNA metabolic processes and regulation activities were differentially expressed in the presence of the mycoviruses
NMR experiment factors numbers with Gauss sums
We factor the number 157573 using an NMR implementation of Gauss sums.Comment: 4 pages 5 figure
Moving towards a wave-resolved approach to forecasting mountain wave induced clear air turbulence
Mountain wave breaking in the lower stratosphere is one of the major causes of atmospheric turbulence encountered in commercial aviation, which in turn is the cause of most weather-related aircraft incidents. In the case of clear air turbulence (CAT), there are no visual clues and pilots are reliant on operational forecasts and reports from other aircraft. Traditionally mountain waves have been sub-grid-scale in global numerical weather prediction (NWP) models, but recent developments in NWP mean that some forecast centres (e.g. the UK Met Office) are now producing operational global forecasts that resolve mountain wave activity explicitly, allowing predictions of mountain wave induced turbulence with greater accuracy and confidence than previously possible. Using a bespoke turbulent kinetic energy diagnostic, the Met Office Unified Model (MetUM) is shown to produce useful forecasts of mountain CAT during three case studies over Greenland, and to outperform the current operational Met Office CAT prediction product (the World Area Forecast Centre (WAFC) London gridded CAT product) in doing so. In a long term, 17-month, verification, MetUM forecasts yield a turbulence prediction hit rate of 80% with an accompanying false alarm rate of under 40%. These skill scores are a considerable improvement on those reported for the mountain wave component of the WAFC product, although no direct comparison is available. The major implication of this work is that sophisticated global NWP models are now sufficiently advanced to provide skilful forecasts of mountain wave turbulence
The crystal structure of the catalytic domain of a eukaryotic guanylate cyclase
<p>Abstract</p> <p>Background</p> <p>Soluble guanylate cyclases generate cyclic GMP when bound to nitric oxide, thereby linking nitric oxide levels to the control of processes such as vascular homeostasis and neurotransmission. The guanylate cyclase catalytic module, for which no structure has been determined at present, is a class III nucleotide cyclase domain that is also found in mammalian membrane-bound guanylate and adenylate cyclases.</p> <p>Results</p> <p>We have determined the crystal structure of the catalytic domain of a soluble guanylate cyclase from the green algae <it>Chlamydomonas reinhardtii </it>at 2.55 Ã… resolution, and show that it is a dimeric molecule.</p> <p>Conclusion</p> <p>Comparison of the structure of the guanylate cyclase domain with the known structures of adenylate cyclases confirms the close similarity in architecture between these two enzymes, as expected from their sequence similarity. The comparison also suggests that the crystallized guanylate cyclase is in an inactive conformation, and the structure provides indications as to how activation might occur. We demonstrate that the two active sites in the dimer exhibit positive cooperativity, with a Hill coefficient of ~1.5. Positive cooperativity has also been observed in the homodimeric mammalian membrane-bound guanylate cyclases. The structure described here provides a reliable model for functional analysis of mammalian guanylate cyclases, which are closely related in sequence.</p
The Berry-Keating Hamiltonian and the Local Riemann Hypothesis
The local Riemann hypothesis states that the zeros of the Mellin transform of
a harmonic-oscillator eigenfunction (on a real or p-adic configuration space)
have real part 1/2. For the real case, we show that the imaginary parts of
these zeros are the eigenvalues of the Berry-Keating hamiltonian H=(xp+px)/2
projected onto the subspace of oscillator eigenfunctions of lower level. This
gives a spectral proof of the local Riemann hypothesis for the reals, in the
spirit of the Hilbert-Polya conjecture. The p-adic case is also discussed.Comment: 9 pages, no figures; v2 included more mathematical background, v3 has
minor edits for clarit
Conservation of the PBL-RBOH immune module in land plants
The rapid production of reactive oxygen species (ROS) is a key signaling output in plant immunity. In the angiosperm model species Arabidopsis thaliana (hereafter Arabidopsis), recognition of non- or altered-self elicitor patterns by cell-surface immune receptors activates the receptor-like cytoplasmic kinases (RLCKs) of the AVRPPHB SUSCEPTIBLE 1 (PBS1)-like (PBL) family, particularly BOTRYTIS-INDUCED KINASE1 (BIK1). BIK1/PBLs in turn phosphorylate the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase RESPIRATORY BURST OXIDASE HOMOLOG D (RBOHD) to induce apoplastic ROS production. PBL and RBOH functions in plant immunity have been extensively characterized in flowering plants. Much less is known about the conservation of pattern-triggered ROS signaling pathways in non-flowering plants. In this study, we show that in the liverwort Marchantia polymorpha (hereafter Marchantia), single members of the RBOH and PBL families, namely MpRBOH1 and MpPBLa, are required for chitin-induced ROS production. MpPBLa directly interacts with and phosphorylates MpRBOH1 at specific, conserved sites within its cytosolic N terminus, and this phosphorylation is essential for chitin-induced MpRBOH1-mediated ROS production. Collectively, our work reveals the functional conservation of the PBL-RBOH module that controls pattern-triggered ROS production in land plants
Food for our future: the nutritional science behind the sustainable fungal protein - mycoprotein. A symposium review.
This is the final version. Available from Cambridge University Press via the DOI in this record. Mycoprotein is a well-established and sustainably produced, protein-rich, high-fibre, whole food source derived from the fermentation of fungus. The present publication is based on a symposium held during the Nutrition Society Summer Conference 2022 in Sheffield that explored 'Food for our Future: The Science Behind Sustainable Fungal Proteins'. A growing body of science links mycoprotein consumption with muscle/myofibrillar protein synthesis and improved cardiometabolic (principally lipid) markers. As described at this event, given the accumulating health and sustainability credentials of mycoprotein, there is great scope for fungal-derived mycoprotein to sit more prominently within future, updated food-based dietary guidelines.Marlow Foods Ltd
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