273 research outputs found
Ekho: A Tool for Recording and Emulating Energy Harvesting Conditions
Harvested energy makes it possible to deploy sensing devices long-term with minimal required upkeep. However, as devices shrink, unpredictable power supplies make it difficult for system designers to anticipate the behavior of these devices. Ekho is tool that records and emulates energy harvesting conditions in order to enable accurate and repeatable testing of these sensing devices. Ekho uses the concept of I-V curves — curves that describe harvesting current in relation to supply voltage — in order to accurately represent harvesting conditions in a form that is independent of the sensing platform and the type of energy that is being harvested. This paper describes extensions to Ekho; it presents the design and an improved implementation, as well as preliminary testing and results. My role in this project has been to reimplement and to extend Ekho. This software was unmaintainable and considerably limited in its ability to emulate energy harvesting conditions. The first implementation of Ekho was a hardware design for an FPGA, which made use of specialized circuits. I refactored this code for a microcontroller, achieving even better performance than before: this new implementation can record harvesting conditions and can emulate changing I-V curves, and I have added back-end programs to ease processing and formatting of data. Initial results show that Ekho is able to replay I-V surfaces while readjusting to the harvesting conditions as frequently as once in 4.3μs. Ekho is able to emulate changing energy conditions, adapting both to changes in supply voltage and energy availability. Ekho can update the I-V curve, which the I-V controller holds in memory during emulation, as frequently as once per millisecond. These results show that Ekho is responsive to changes in the harvesting current and could be working properly
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In Utero Gene Therapy (IUGT) Using GLOBE Lentiviral Vector Phenotypically Corrects the Heterozygous Humanised Mouse Model and Its Progress Can Be Monitored Using MRI Techniques
Funder: UK Thalassaemia SocietyAbstract: In utero gene therapy (IUGT) to the fetal hematopoietic compartment could be used to treat congenital blood disorders such as β-thalassemia. A humanised mouse model of β-thalassemia was used, in which heterozygous animals are anaemic with splenomegaly and extramedullary hematopoiesis. Intrahepatic in utero injections of a β globin-expressing lentiviral vector (GLOBE), were performed in fetuses at E13.5 of gestation. We analysed animals at 12 and 32 weeks of age, for vector copy number in bone marrow, peripheral blood liver and spleen and we performed integration site analysis. Compared to noninjected heterozygous animals IUGT normalised blood haemoglobin levels and spleen weight. Integration site analysis showed polyclonality. The left ventricular ejection fraction measured using magnetic resonance imaging (MRI) in treated heterozygous animals was similar to that of normal non-β-thalassemic mice but significantly higher than untreated heterozygous thalassemia mice suggesting that IUGT ameliorated poor cardiac function. GLOBE LV-mediated IUGT normalised the haematological and anatomical phenotype in a heterozygous humanised model of β-thalassemia
Effects of light environment during growth on the expression of cone opsin genes and behavioral spectral sensitivities in guppies (Poecilia reticulata)
The power of pictures: Vertical picture angles in power pictures
Abstract:
Conventional wisdom suggests that variations in vertical picture angle cause the subject to appear more powerful when depicted from below and less powerful when depicted from above. However, do the media actually use such associations to represent individual differences in power? We argue that the diverse perspectives of evolutionary, social learning, and embodiment theories all suggest that the association between verticality and power is relatively automatic and should, therefore, be visible in the portrayal of powerful and powerless individuals in the media. Four archival studies (with six samples) provide empirical evidence for this hypothesis and indicate that a salience power context reinforces this effect. In addition, two experimental studies confirm these effects for individuals producing media content. We discuss potential implications of this effect
PEARLS: A Potentially Isolated Quiescent Dwarf Galaxy with a TRGB Distance of 31 Mpc
A wealth of observations have long suggested that the vast majority of
isolated classical dwarf galaxies (- M) are currently
star-forming. However, recent observations of the large abundance of
"Ultra-Diffuse Galaxies" beyond the reach of previous large spectroscopic
surveys suggest that our understanding of the dwarf galaxy population may be
incomplete. Here we report the serendipitous discovery of an isolated quiescent
dwarf galaxy in the nearby Universe, which was imaged as part of the PEARLS GTO
program. Remarkably, individual red-giant branch stars are visible in this
near-IR imaging, suggesting a distance of Mpc, and a wealth of archival
photometry point to an sSFR of yr. Spectra obtained
with the Lowell Discovery Telescope find a recessional velocity consistent with
the Hubble Flow and km/s separated from the nearest massive galaxy in
SDSS, suggesting that this galaxy was either quenched from internal mechanisms
or had a very high-velocity interaction with a nearby massive galaxy in the
past. This analysis highlights the possibility that many nearby quiescent dwarf
galaxies are waiting to be discovered and that JWST has the potential to
identify them.Comment: Submitted to ApJ Letters. Comments welcome
Weber and church governance: religious practice and economic activity
The debate about the relationship between religion and economic activity in the wake of Weber has been cast largely in terms of belief and values. This article suggests an alternative focus on practice. It argues that taken for granted practices of church governance formed to-hand resources for the organization of economic activity. The argument is developed through an examination of the historical development of church governance practices in the Presbyterian Church of Scotland, with particular emphasis on the way in which theological belief gave rise to practices of accountability and record keeping. In turn such practices contributed to a ‘culture of organization’ which had implications for economic activity. A focus on governance practices can help to illuminate enduring patterns of difference in the organization of economic activity
Ten facts about land systems for sustainability
Land use is central to addressing sustainability issues, including biodiversity conservation, climate change, food security, poverty alleviation, and sustainable energy. In this paper, we synthesize knowledge accumulated in land system science, the integrated study of terrestrial social-ecological systems, into 10 hard truths that have strong, general, empirical support. These facts help to explain the challenges of achieving sustainability in land use and thus also point toward solutions. The 10 facts are as follows: 1) Meanings and values of land are socially constructed and contested; 2) land systems exhibit complex behaviors with abrupt, hard-to-predict changes; 3) irreversible changes and path dependence are common features of land systems; 4) some land uses have a small footprint but very large impacts; 5) drivers and impacts of land-use change are globally interconnected and spill over to distant locations; 6) humanity lives on a used planet where all land provides benefits to societies; 7) land-use change usually entails trade-offs between different benefits—"win–wins" are thus rare; 8) land tenure and land-use claims are often unclear, overlapping, and contested; 9) the benefits and burdens from land are unequally distributed; and 10) land users have multiple, sometimes conflicting, ideas of what social and environmental justice entails. The facts have implications for governance, but do not provide fixed answers. Instead they constitute a set of core principles which can guide scientists, policy makers, and practitioners toward meeting sustainability challenges in land use
Highly Sensitive and Specific Detection of Rare Variants in Mixed Viral Populations from Massively Parallel Sequence Data
Viruses diversify over time within hosts, often undercutting the effectiveness of host defenses and therapeutic interventions. To design successful vaccines and therapeutics, it is critical to better understand viral diversification, including comprehensively characterizing the genetic variants in viral intra-host populations and modeling changes from transmission through the course of infection. Massively parallel sequencing technologies can overcome the cost constraints of older sequencing methods and obtain the high sequence coverage needed to detect rare genetic variants (<1%) within an infected host, and to assay variants without prior knowledge. Critical to interpreting deep sequence data sets is the ability to distinguish biological variants from process errors with high sensitivity and specificity. To address this challenge, we describe V-Phaser, an algorithm able to recognize rare biological variants in mixed populations. V-Phaser uses covariation (i.e. phasing) between observed variants to increase sensitivity and an expectation maximization algorithm that iteratively recalibrates base quality scores to increase specificity. Overall, V-Phaser achieved >97% sensitivity and >97% specificity on control read sets. On data derived from a patient after four years of HIV-1 infection, V-Phaser detected 2,015 variants across the ∼10 kb genome, including 603 rare variants (<1% frequency) detected only using phase information. V-Phaser identified variants at frequencies down to 0.2%, comparable to the detection threshold of allele-specific PCR, a method that requires prior knowledge of the variants. The high sensitivity and specificity of V-Phaser enables identifying and tracking changes in low frequency variants in mixed populations such as RNA viruses
Search for Ultraheavy Dark Matter from Observations of Dwarf Spheroidal Galaxies with VERITAS
Dark matter is a key piece of the current cosmological scenario, with weakly
interacting massive particles (WIMPs) a leading dark matter candidate. WIMPs
have not been detected in their conventional parameter space (100 GeV 100 TeV), a mass range accessible with current Imaging
Atmospheric Cherenkov Telescopes. As ultraheavy dark matter (UHDM; 100 TeV) has been suggested as an under-explored alternative to the
WIMP paradigm, we search for an indirect dark matter annihilation signal in a
higher mass range (up to 30 PeV) with the VERITAS gamma-ray observatory. With
216 hours of observations of four dwarf spheroidal galaxies, we perform an
unbinned likelihood analysis. We find no evidence of a -ray signal from
UHDM annihilation above the background fluctuation for any individual dwarf
galaxy nor for a joint-fit analysis, and consequently constrain the
velocity-weighted annihilation cross section of UHDM for dark matter particle
masses between 1 TeV and 30 PeV. We additionally set constraints on the allowed
radius of a composite UHDM particle.Comment: 10 pages, 7 figure
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