1,149 research outputs found

    Aid, Public Expenditure and Dutch Disease

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    Contemporary policy debates on the macroeconomics of aid often concentrate on short-run Dutch disease effects, ignoring the possible supply side impact of aidâfinanced public expenditure. We develop a simple model of aid and public expenditure in which public infrastructure capital generates an inter-temporal productivity spillover for both tradable and non-tradable sectors, where these productivity effects may display sector-specific biases. The model also allows for non-homothetic demands. We then use an extended version of this model, calibrated to contemporary conditions in Uganda, to simulate the effect of a step increase in net aid flows. Our simulations show that beyond the short-run, where Dutch disease effects are present, the relationship between enhanced aid flows, real exchange rates and welfare is less straightforward than simple models of aid suggest. We show that public infrastructure which generates a productivity bias in favour of non-tradable production delivers the largest aggregate return to aid, with the real exchange rate appreciation reduced or reversed and enhanced export performance, but it does so at the cost of a deterioration in the income distribution. Income gains accrue predominantly to urban skilled and unskilled households, leaving the rural poor relatively worse off. Under plausible parameterizations of the model the rural poor may also be worse ff in absolute terms.Aid, Dutch Disease, Public Expenditure, Africa

    Fiscal Policy Design in Low-Income Countries

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    Fiscal policy, Macro-economic stabilization, Sub-Saharan Africa

    Developing methods to construct ring pucker free energy hypersurfaces applied to the analysis of glycosidase enzyme catalytic mechanisms

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    Includes bibliographical references.Carbohydrates consist of one or more sub-units usually various 5- and 6-membered cycles (furanoses and pyranoses) which can twist, bend or flip into a variety of conformers that differ in strain - this is ring puckering. These puckers notably the strained puckering conformers are observed during enzymatically assisted bond formation or cleavage of the glycosidic bonds of carbohydrate substrates. In this thesis, the free energy of ring puckering is calculated by implementing the Hill-Reilly reduced coordinate pucker description into the sampling enhancing Free Energies from Adaptive Reaction Coordinate Forces (FEARCF) method. FEARCF non-Boltzmann simulations of prototypical sugars β-Dribose and β-D-glucose converged to yield free energy pucker surfaces and volumes when using several semi-empirical QM methods - AM1, PM3, PM3CARB-1 and SCC-DFTB. From this, the accessible puckering conformations and minimum free energy paths of puckering were reasoned An analysis of the furanose and pyranose free energy pucker surfaces and volumes compared with both Density Functional Theory RB3LYP/6-311++G** optimised structures and a Hartree-Fock free energy surface revealed that SCC-DFTB provides the best semi-empirical description of 5- and 6- membered carbohydrate ring deformation. This illustrates that necessary high energy ring conformations observed in enzymatic binding sites requires the enzyme to induce and preserve high energy conformations required for successful hydrolyses and synthesis of the glycosidic bond. To further test this hypothesis, a 5- and 6-membered cycle were studied within enzymatic environments. The polysaccharide cellulose contains β 1-4 linked glucose subunit and is degraded by cellulase, a glycosidase. Specifically, the retaining cellobiohydrolase I (CBHI) of Trichoderma Reesei which cleaves cellobiose units from crystalline cellulose.The free energy volumes of puckering for the glucose sub-unit (in the catalytic position of an 8 unit cellulosic fragment - cellooctaose) were calculated and explored in vacuum, water and in the active site of CBHI. It was observed that the binding pocket of enzymes limits the ring pucker and that the active site amino acids preferentially stabilise certain puckering conformations. For CBHI, the first part of the glycosidase reaction is the glycosylation step. This was driven to completion during SCC-DFTB QM/MD FEARCF calculations where GLU212, ASP214 and GLU217 and part of the substrate were treated quantum mechanically. The general hybrid orbital method was used to connect the QM and MM regions. The free energy barriers of glycosylation were computed and the puckering statistics during the conversion of cellooctaose to products were correlated with this. Guanosine, a 5-membered ribose derivative is phosphorylated by Purine Nucleoside Phosphorylase (PNP) in order to salvage the guanine base. The effect of the PNP protein environment on ring pucker was studied by using FEARCF SCC-DFTB QM/MD non Boltzmann free energy calculations to quantify the pucker change induced in guanosine when changing environment from vacuum, to water and to the protein. In vacuo, the E4 and E1 pucker conformers were observed as minima. Upon solvation, the puckering phase space became less restricted with the 3T4 and 2T3 pucker conformers as minima. In the PNP active site pucker became restricted with only the 4E conformer observed

    Ambient Aesthetics in the Acousmatic Domain: a portfolio of original compositions

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    This text is the supporting document to a portfolio thesis of musical compositions submitted for the degree of Doctor of Philosophy in the Department of Music at The University of Sheffield. It acts as a guide to the ideas and methodologies behind the creation of the compositions. The portfolio consists of nine acousmatic compositions composed between 2015 and 2020, of which seven are stereophonic, one is quadraphonic, and one is octophonic. Following an introduction to the contextual considerations of this approach, this text discusses the works within the portfolio, in chronological order, revealing the development of a compositional practice rooted in the acousmatic tradition, yet drawing influence from ideas and techniques associated with ambient music. As the discussion unfolds, a working definition of ambience in music - ambient traits - is formed. We see how the musical traits commonly associated with ambient music are equally common to works found in the acousmatic field. Finally, I explain how such traits have informed my own compositional practice, while highlighting the broader ambient approaches within my own compositions. Across its duration, the portfolio explores a wide range of approaches to incorporating ambience within an acousmatic practice, and shows how it is possible for these two streams of composition to be combined in the pursuit of various musical goals

    Oxidative phosphorylation and lacunar stroke: Genome-wide enrichment analysis of common variants.

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    OBJECTIVE: We investigated whether oxidative phosphorylation (OXPHOS) abnormalities were associated with lacunar stroke, hypothesizing that these would be more strongly associated in patients with multiple lacunar infarcts and leukoaraiosis (LA). METHODS: In 1,012 MRI-confirmed lacunar stroke cases and 964 age-matched controls recruited from general practice surgeries, we investigated associations between common genetic variants within the OXPHOS pathway and lacunar stroke using a permutation-based enrichment approach. Cases were phenotyped using MRI into those with multiple infarcts or LA (MLI/LA) and those with isolated lacunar infarcts (ILI) based on the number of subcortical infarcts and degree of LA, using the Fazekas grading. Using gene-level association statistics, we tested for enrichment of genes in the OXPHOS pathway with all lacunar stroke and the 2 subtypes. RESULTS: There was a specific association with strong evidence of enrichment in the top 1% of genes in the MLI/LA (subtype p = 0.0017) but not in the ILI subtype (p = 1). Genes in the top percentile for the all lacunar stroke analysis were not significantly enriched (p = 0.07). CONCLUSIONS: Our results implicate the OXPHOS pathway in the pathogenesis of lacunar stroke, and show the association is specific to patients with the MLI/LA subtype. They show that MRI-based subtyping of lacunar stroke can provide insights into disease pathophysiology, and imply that different radiologic subtypes of lacunar stroke subtypes have distinct underlying pathophysiologic processes.Hugh Markus is supported by an NIHR Senior Investigator award. Hugh Markus and Steve Bevan are supported by the NIHR Cambridge University Hospitals Comprehensive Biomedical Research Centre. Collection of the UK Young Lacunar Stroke Resource was primarily supported by a Functional Genomics grant from the Wellcome Trust with additional support from the Stroke Association. Genotyping and MT were supported by a project grant from the Stroke Association (TSA 2013/01). Dr. Anderson is supported by NIH-NINDS K23 NS086873 and a Fellowship in Therapeutic Investigation sponsored by the Massachusetts General Hospital Department of Neurology and Biogen Idec, Inc.This is the final version of the article. It first appeared from Wolters Kluwer via http://dx.doi.org/10.1212/WNL.000000000000226

    Different strokes for different folks? Revealing the physical characteristics of smartphone users from their swipe gestures

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    AbstractAnthropometrics show that the lengths of many human body segments follow a common proportional relationship. To know the length of one body segment – such as a thumb – potentially provides a predictive route to other physical characteristics, such as overall standing height. In this study, we examined whether it is feasible that the length of a person׳s thumb could be revealed from the way in which they complete swipe gestures on a touchscreen-based smartphone.From a corpus of approx. 19,000 swipe gestures captured from 178 volunteers, we found that people with longer thumbs complete swipe gestures with shorter completion times, higher speeds and with higher accelerations than people with shorter thumbs. These differences were also observed to exist between our male and female volunteers, along with additional differences in the amount of touch pressure applied to the screen.Results are discussed in terms of linking behavioural and physical biometrics

    Hematodinium sp. infection does not drive collateral disease contraction in a crustacean host

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    Host, pathogen, and environment are determinants of the disease triangle, the latter being a key driver of disease outcomes and persistence within a community. The dinoflagellate genus Hematodinium is detrimental to crustaceans globally – considered to suppress the innate defences of hosts, making them more susceptible to co-infections. Evidence supporting immune suppression is largely anecdotal and sourced from diffuse accounts of compromised decapods. We used a population of shore crabs (Carcinus maenas), where Hematodinium sp. is endemic, to determine the extent of collateral infections across two distinct environments (open-water, semi-closed dock). Using a multi-resource approach (PCR, histology, haematology, population genetics, eDNA), we identified 162 Hematodinium-positive crabs and size/sex-matched these to 162 Hematodinium-free crabs out of 1191 analysed. Crabs were interrogated for known additional disease-causing agents; haplosporidians, microsporidians, mikrocytids, Vibrio spp., fungi, Sacculina, trematodes, and haemolymph bacterial loads. We found no significant differences in occurrence, severity, or composition of collateral infections between Hematodinium-positive and Hematodinium-free crabs at either site, but crucially, we recorded site-restricted blends of pathogens. We found no gross signs of host cell immune reactivity towards Hematodinium in the presence or absence of other pathogens. We contend Hematodinium sp. is not the proximal driver of co-infections in shore crabs, which suggests an evolutionary drive towards latency in this environmentally plastic host

    Towards a Pseudocapacitive Battery: Benchmarking the Capabilities of Quantized Capacitance for Energy Storage

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    Despite being capable of very fast charging, the pseudocapacitive properties of electrochemical capacitors still require significant research to attain energy densities comparable to that of batteries. Herein we discuss and theoretically benchmark the physics of quantized capacitance as a Faradaic charge storage mechanism, providing near “ideal” pseudocapacitive properties in the context of batterylike energy storage. Through careful electrolyte and reactant engineering, our physical analysis suggests that this less explored “pseudocapacitive battery” mechanism could provide power densities of approximately 10 4 W/L combined with volumetric energy densities in the range of 100 Wh/L (or potentially greater). These benchmarks are arrived at though a comprehensive analysis of two-dimensional (2D) graphitic nanoparticles considering the impact of solvation, electron-electron interactions, and electron transfer processes. In general, our findings indicate that 2D nanomaterials exhibiting quantized capacitance provide a promising and underexplored physical axis within electrochemical capacitors towards realizing very fast charging at energy densities comparable to that of batteries
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