4,125 research outputs found
Migrating functionality from ROMs to embedded multipliers
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Towards an early warning system for Rhodesian sleeping sickness in savannah areas: man-like traps for tsetse flies
Background: In the savannahs of East and Southern Africa, tsetse flies (Glossina spp.) transmit Trypanosoma brucei
rhodesiense which causes Rhodesian sleeping sickness, the zoonotic form of human African trypanosomiasis. The flies feed mainly on wild and domestic animals and are usually repelled by humans. However, this innate aversion to humans can be undermined by environmental stresses on tsetse populations, so increasing disease risk. To monitor changes in risk, we need traps designed specifically to quantify the responsiveness of savannah tsetse to humans, but the traps currently available are designed to simulate other hosts.
Methodology/Principal Findings: In Zimbabwe, two approaches were made towards developing a man-like trap for savannah tsetse: either modifying an ox-like trap or creating new designs. Tsetse catches from a standard ox-like trap used
with and without artificial ox odor were reduced by two men standing nearby, by an average of 34% for Glossina morsitans
morsitans and 56% for G. pallidipes, thus giving catches more like those made by hand-nets from men. Sampling by
electrocuting devices suggested that the men stopped flies arriving near the trap and discouraged trap-entering responses. Most of human repellence was olfactory, as evidenced by the reduction in catches when the trap was used with the odor of hidden men. Geranyl acetone, known to occur in human odor, and dispensed at 0.2 mg/h, was about as repellent as human odor but not as powerfully repellent as wood smoke. New traps looking and smelling like men gave catches like those from men.
Conclusion/Significance: Catches from the completely new man-like traps seem too small to give reliable indices of human repellence. Better indications would be provided by comparing the catches of an ox-like trap either with or without artificial human odor. The chemistry and practical applications of the repellence of human odor and smoke deserve further study
Multiscapes and urbanisation: The case for spatial agroecology
The two most significant signatures of the Anthropocene—agriculture and urbanisation— have yet to be studied synoptically. The term periurban is used to describe territory where the urbanising trend of the planet extends into multiscapes. A periurban praxis is required that spatially reconciles urbanisation and agriculture, simultaneously permitting urban growth and the enhancement of critical ecosystem services provided by agricultural hinterlands. This paper presents a synthesis of four fields of ecological research that converge on periurban multiscapes—ecological urbanism, landscape ecology, ecosystem services science and agroecology. By applying an ecosystem services approach, a diagram is developed that connects these fields as a holistic praxis for spatially optimising periurban multiscapes for ecosystem services performance. Two spatial qualities of agroecology—‘ES Density’ and ‘ES Plasticity’—potentiate recent areas of research in each of the other three fields—ecology for the city from ecological urbanism, landscape metrics from landscape ecology (particularly the potential application of fractals and surface metrics) and ecosystem services supply and demand mapping and ‘ES Space’ theory from ecosystems services science. While the multifunctional value of agroecological systems is becoming widely accepted, this paper focuses on agroecology’s specific spatial value and its unique capacity to supply ecosystem services specifically tailored to the critical ecosystemic demands of periurban multiscapes.R.M. is funded by a Food Transitions 2050 doctoral scholarship (Food Transitions 2050 Joint Postgraduate School, Faculty of Agriculture and Life Sciences, Lincoln University) and the APC was funded by the Lincoln University Open Access Publishing Fund
Controlled depolymerisation, as assessed by analytical ultracentrifugation, of low molecular weight chitosan for potential use in archaeological conservation
The heterogeneity and molecular weight of a chitosan of low molecular weight (molar mass) and low degree of acetylation (0.1), for potential use as a consolidant for decayed archaeological wood, has been examined by sedimentation velocity and sedimentation equilibriumin the analytical ultracentrifuge before and after depolymerisation. Sedimentation velocity before polymerisation revealed a uniform distribution of sedimentation coefficient with little concentration dependence. SEDFIT-MSTAR analysis revealed a weight average molecular weight Mw of (14.2 + 1.2) kDa, and polydispersity index of ~ 1.2. Further analysis using MULTISIG revealed a distribution of material between 2-20 kDa and consistent with the weight average Mw. Controlled depolymerisation using hydrogen peroxide and UV in an acetic acid medium reduced this to (4.9 + 0.7) kDa, with a similar polydispersity. The depolymerised material appears to be within the range that has been predicted to fully penetrate into archaeological wood. The consequences for this and the use of the analytical ultracentrifuge in wood conservation strategies is considered
A new mouse line with reduced GluA2 Q/R site RNA editing exhibits loss of dendritic spines, hippocampal CA1-neuron loss, learning and memory impairments and NMDA receptor-independent seizure vulnerability.
Calcium (Ca2+)-permeable AMPA receptors may, in certain circumstances, contribute to normal synaptic plasticity or to neurodegeneration. AMPA receptors are Ca2+-permeable if they lack the GluA2 subunit or if GluA2 is unedited at a single nucleic acid, known as the Q/R site. In this study, we examined mice engineered with a point mutation in the intronic editing complementary sequence (ECS) of the GluA2 gene, Gria2. Mice heterozygous for the ECS mutation (named GluA2+/ECS(G)) had a ~ 20% reduction in GluA2 RNA editing at the Q/R site. We conducted an initial phenotypic analysis of these mice, finding altered current-voltage relations (confirming expression of Ca2+-permeable AMPA receptors at the synapse). Anatomically, we observed a loss of hippocampal CA1 neurons, altered dendritic morphology and reductions in CA1 pyramidal cell spine density. Behaviourally, GluA2+/ECS(G) mice exhibited reduced motor coordination, and learning and memory impairments. Notably, the mice also exhibited both NMDA receptor-independent long-term potentiation (LTP) and vulnerability to NMDA receptor-independent seizures. These NMDA receptor-independent seizures were rescued by the Ca2+-permeable AMPA receptor antagonist IEM-1460. In summary, unedited GluA2(Q) may have the potential to drive NMDA receptor-independent processes in brain function and disease. Our study provides an initial characterisation of a new mouse model for studying the role of unedited GluA2(Q) in synaptic and dendritic spine plasticity in disorders where unedited GluA2(Q), synapse loss, neurodegeneration, behavioural impairments and/or seizures are observed, such as ischemia, seizures and epilepsy, Huntington's disease, amyotrophic lateral sclerosis, astrocytoma, cocaine seeking behaviour and Alzheimer's disease
Effect of Standard vs Intensive Blood Pressure Control on Cerebral Blood Flow in Small Vessel Disease The PRESERVE Randomized Clinical Trial
Importance: Blood pressure lowering is considered neuroprotective in patients with cerebral small vessel disease, however more “intensive” regimens may increase cerebral hypoperfusion. We examined the effect of intensive vs. standard blood pressure treatment on cerebral perfusion in severe small vessel disease patients.
Objective: To determine whether intensive vs. standard blood pressure lowering over 3 months causes decreased cerebral perfusion.
Design, Setting and Participants: This randomised, parallel, controlled, blinded-outcomes clinical trial took place in 2 English university medical centres. A central, online randomisation system (1:1 ratio) allocated grouping. 70 hypertensive patients with MRI confirmed symptomatic lacunar infarct and confluent white matter hyperintensities were recruited between 2012 and 2015, and randomised (36/34 in standard/intensive arms). Analysable data were available in 62 patients, 33/29 in the standard/intensive groups respectively, for intention to treat analysis. This experiment examines the 3 month follow-up period.
Intervention: Patients were randomised to “standard” (systolic=130-140mmHg) or “intensive” (systolic=<125mmHg) blood pressure targets, to be achieved through medication regimen changes.
Main Outcome and Measure: Cerebral perfusion was determined using arterial spin labelling; the primary end point was change in global perfusion between baseline and 3 months, compared between treatment groups by ANOVA. Linear regression compared change in perfusion against change in blood pressure. MR scan analysis was blinded to treatment arm.
Results: Patients were 69.3 years old (mean) and 59.7% male. Mean(SD) systolic blood pressure reduced by 8(12) and 27(17)mmHg in the standard/intensive groups, respectively (p<0.001), with achieved pressures of 141(13) and 126(10) mmHg respectively. Change in global perfusion did not differ between treatment arms: standard, mean(SD) (ml/min/100g)= -0.5(9.4); intensive, 0.7(8.6), partial ETA2= 0.004, 95% CI= -3.6–5.8, p= 0.63. No differences were observed when analysis examined grey/white matter only, or was confined to those achieving target blood pressure. The number of adverse events did not differ between treatment groups (standard/intensive mean(SD)= .21(.65)/.32(.75), p=.44).
Conclusions and Relevance: Intensive blood pressure lowering did not reduce cerebral perfusion in severe small vessel disease.This study was funded by a joint Stroke Association/British Heart Foundation program grant (TSA BHF 2010/01). The study received additional support from the Newcastle Biomedical Research Centre, which is funded by the National Institute for Health Research (NIHR). Drs O’Brien, Ford, and Markus are supported by NIHR Senior Investigator awards. Drs O’Brien and Markus are also supported by the Cambridge University Hospitals NIHR Comprehensive Biomedical Research Centre
The Atlantic Ocean at the last glacial maximum: 1. Objective mapping of the GLAMAP sea-surface conditions
Recent efforts of the German paleoceanographic community have resulted in a unique data set of reconstructed sea-surface temperature for the Atlantic Ocean during the Last Glacial Maximum, plus estimates for the extents of glacial sea ice. Unlike prior attempts, the contributing research groups based their data on a common definition of the Last Glacial Maximum chronozone and used the same modern reference data for calibrating the different transfer techniques. Furthermore, the number of processed sediment cores was vastly increased. Thus the new data is a significant advance not only with respect to quality, but also to quantity. We integrate these new data and provide monthly data sets of global sea-surface temperature and ice cover, objectively interpolated onto a regular 1°x1° grid, suitable for forcing or validating numerical ocean and atmosphere models. This set is compared to an existing subjective interpolation of the same base data, in part by employing an ocean circulation model. For the latter purpose, we reconstruct sea surface salinity from the new temperature data and the available oxygen isotope measurements
Evaluation of Phage Display Discovered Peptides as Ligands for Prostate-Specific Membrane Antigen (PSMA)
The aim of this study was to identify potential ligands of PSMA suitable for further development as novel PSMA-targeted peptides using phage display technology. The human PSMA protein was immobilized as a target followed by incubation with a 15-mer phage display random peptide library. After one round of prescreening and two rounds of screening, high-stringency screening at the third round of panning was performed to identify the highest affinity binders. Phages which had a specific binding activity to PSMA in human prostate cancer cells were isolated and the DNA corresponding to the 15-mers were sequenced to provide three consensus sequences: GDHSPFT, SHFSVGS and EVPRLSLLAVFL as well as other sequences that did not display consensus. Two of the peptide sequences deduced from DNA sequencing of binding phages, SHSFSVGSGDHSPFT and GRFLTGGTGRLLRIS were labeled with 5-carboxyfluorescein and shown to bind and co-internalize with PSMA on human prostate cancer cells by fluorescence microscopy. The high stringency requirements yielded peptides with affinities KD∼1 μM or greater which are suitable starting points for affinity maturation. While these values were less than anticipated, the high stringency did yield peptide sequences that apparently bound to different surfaces on PSMA. These peptide sequences could be the basis for further development of peptides for prostate cancer tumor imaging and therapy. © 2013 Shen et al
Stablecoins 2.0: Economic Foundations and Risk-based Models
Stablecoins are one of the most widely capitalized type of cryptocurrency.
However, their risks vary significantly according to their design and are often
poorly understood. We seek to provide a sound foundation for stablecoin theory,
with a risk-based functional characterization of the economic structure of
stablecoins. First, we match existing economic models to the disparate set of
custodial systems. Next, we characterize the unique risks that emerge in
non-custodial stablecoins and develop a model framework that unifies existing
models from economics and computer science. We further discuss how this
modeling framework is applicable to a wide array of cryptoeconomic systems,
including cross-chain protocols, collateralized lending, and decentralized
exchanges. These unique risks yield unanswered research questions that will
form the crux of research in decentralized finance going forward
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Biology and evolutionary games
This chapter surveys some evolutionary games used in biological sciences. These include the Hawk-Dove game, the Prisoner’s Dilemma, Rock–Paper–Scissors, the war of attrition, the Habitat Selection game, predatorprey games, and signalling games
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