162 research outputs found
A new invariant on hyperbolic Dehn surgery space
In this paper we define a new invariant of the incomplete hyperbolic
structures on a 1-cusped finite volume hyperbolic 3-manifold M, called the
ortholength invariant. We show that away from a (possibly empty) subvariety of
excluded values this invariant both locally parameterises equivalence classes
of hyperbolic structures and is a complete invariant of the Dehn fillings of M
which admit a hyperbolic structure. We also give an explicit formula for the
ortholength invariant in terms of the traces of the holonomies of certain loops
in M. Conjecturally this new invariant is intimately related to the boundary of
the hyperbolic Dehn surgery space of M.Comment: Published by Algebraic and Geometric Topology at
http://www.maths.warwick.ac.uk/agt/AGTVol2/agt-2-23.abs.htm
âCultivated with great carefulnessâ : Chinese market gardening, urban food supplies and public health in Australasia, 1860s-1950s
Abstract: Our article examines Chinese market gardening in Australasia and changes in their agricultural practices, notably the gradual adoption of artificial fertilisers over the twentieth century, consequent with declining supplies of human and animal manure in cities. We highlight the centrality of Chinese market gardens to urban food supplies in Australasia. In light of the public health revolution, we also demonstrate the contentious issue of Chinese use of human waste or nightsoil as fertiliser. We show that urbanisation and the public health revolution transformed manure from a valued agricultural resource into a problematic waste product. Our article reveals a range of attitudes and beliefs towards Chinese market gardening that complicate simplistic narratives of uniform colonial racism
Measurement of the state of stress in silicon with micro-Raman spectroscopy
Micro-Raman spectroscopy has been widely used to measure local stresses in silicon and other cubic materials. However, a single (scalar) line position measurement cannot determine the complete stress state unless it has a very simple form such as uniaxial. Previously published micro-Raman strategies designed to determine additional elements of the stress tensor take advantage of the polarization and intensity of the Raman-scattered light, but these strategies have not been validated experimentally. In this work, we test one such stategy [S. Narayanan, S. Kalidindi, and L. Schadler, J. Appl. Phys. 82, 2595 (1997)] for rectangular (110)- and (111)-orientated silicon wafers. The wafers are subjected to a bending stress using a custom-designed apparatus, and the state of (plane) stress is modeled with ABAQUS. The Raman shifts are calculated using previously published values for silicon phonon deformation potentials. The experimentally measured values for ÏxxÏxx, ÏyyÏyy, and ÏxyÏxy at the silicon surface are in good agreement with those calculated with the ABAQUS model.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70888/2/JAPIAU-96-12-7195-1.pd
Patterns of production and consumption of coarse to semi-fine pottery at Early Iron Age Knossos
This paper presents the results of a large-scale petrological study of Early Iron Age coarsewares from North-Central Crete. 210 samples were taken for analysis from six locations at Knossos, representing distinct funerary, domestic and ritual contexts. The bulk of these (188) can be divided into seven fabric groups, with 22 loners or pairs. Four of the seven fabrics exhibit a mineralogy that is consistent with local geology. Three of the fabric groups however appear to be non-local, and two of these fabrics are cooking wares. A non-Cretan,Cycladic sources is suggested for these two fabric groups. There appears to be a major change in the source of Knossian fabrics after 850 BC, and this may be linked to wider Mediterranean connections
Exome Sequencing in Suspected Monogenic Dyslipidemias
Abstract
BACKGROUND:
-Exome sequencing is a promising tool for gene mapping in Mendelian disorders. We utilized this technique in an attempt to identify novel genes underlying monogenic dyslipidemias.
METHODS AND RESULTS:
-We performed exome sequencing on 213 selected family members from 41 kindreds with suspected Mendelian inheritance of extreme levels of low-density lipoprotein (LDL) cholesterol (after candidate gene sequencing excluded known genetic causes for high LDL cholesterol families) or high-density lipoprotein (HDL) cholesterol. We used standard analytic approaches to identify candidate variants and also assigned a polygenic score to each individual in order to account for their burden of common genetic variants known to influence lipid levels. In nine families, we identified likely pathogenic variants in known lipid genes (ABCA1, APOB, APOE, LDLR, LIPA, and PCSK9); however, we were unable to identify obvious genetic etiologies in the remaining 32 families despite follow-up analyses. We identified three factors that limited novel gene discovery: (1) imperfect sequencing coverage across the exome hid potentially causal variants; (2) large numbers of shared rare alleles within families obfuscated causal variant identification; and (3) individuals from 15% of families carried a significant burden of common lipid-related alleles, suggesting complex inheritance can masquerade as monogenic disease.
CONCLUSIONS:
-We identified the genetic basis of disease in nine of 41 families; however, none of these represented novel gene discoveries. Our results highlight the promise and limitations of exome sequencing as a discovery technique in suspected monogenic dyslipidemias. Considering the confounders identified may inform the design of future exome sequencing studies
Growth rings show limited evidence for ungulates' potential to suppress shrubs across the Arctic
Global warming has pronounced effects on tundra vegetation, and rising mean temperatures increase plant growth potential across the Arctic biome. Herbivores may counteract the warming impacts by reducing plant growth, but the strength of this effect may depend on prevailing regional climatic conditions. To study how ungulates interact with temperature to influence growth of tundra shrubs across the Arctic tundra biome, we assembled dendroecological data from 20 sites, comprising 1153 individual shrubs and 223 63 annual growth rings. Evidence for ungulates suppressing shrub radial growth was only observed at intermediate summer temperatures (6.5 degrees C-9 degrees C), and even at these temperatures the effect was not strong. Multiple factors, including forage preferences and landscape use by the ungulates, and favourable climatic conditions enabling effective compensatory growth of shrubs, may weaken the effects of ungulates on shrubs, possibly explaining the weakness of observed ungulate effects. Earlier local studies have shown that ungulates may counteract the impacts of warming on tundra shrub growth, but we demonstrate that ungulates' potential to suppress shrub radial growth is not always evident, and may be limited to certain climatic conditions
Search for Eccentric Black Hole Coalescences during the Third Observing Run of LIGO and Virgo
Despite the growing number of confident binary black hole coalescences
observed through gravitational waves so far, the astrophysical origin of these
binaries remains uncertain. Orbital eccentricity is one of the clearest tracers
of binary formation channels. Identifying binary eccentricity, however, remains
challenging due to the limited availability of gravitational waveforms that
include effects of eccentricity. Here, we present observational results for a
waveform-independent search sensitive to eccentric black hole coalescences,
covering the third observing run (O3) of the LIGO and Virgo detectors. We
identified no new high-significance candidates beyond those that were already
identified with searches focusing on quasi-circular binaries. We determine the
sensitivity of our search to high-mass (total mass ) binaries
covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to
compare model predictions to search results. Assuming all detections are indeed
quasi-circular, for our fiducial population model, we place an upper limit for
the merger rate density of high-mass binaries with eccentricities at Gpc yr at 90\% confidence level.Comment: 24 pages, 5 figure
Open data from the third observing run of LIGO, Virgo, KAGRA and GEO
The global network of gravitational-wave observatories now includes five
detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600.
These detectors collected data during their third observing run, O3, composed
of three phases: O3a starting in April of 2019 and lasting six months, O3b
starting in November of 2019 and lasting five months, and O3GK starting in
April of 2020 and lasting 2 weeks. In this paper we describe these data and
various other science products that can be freely accessed through the
Gravitational Wave Open Science Center at https://gwosc.org. The main dataset,
consisting of the gravitational-wave strain time series that contains the
astrophysical signals, is released together with supporting data useful for
their analysis and documentation, tutorials, as well as analysis software
packages.Comment: 27 pages, 3 figure
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