10,729 research outputs found
Pion Charge Exchange on Deuterium
We investigate quantum corrections to a classical intranuclear cascade
simulation of pion single charge exchange on the deuteron. In order to separate
various effects the orders of scattering need to be distinguished and, to that
end, we develop signals for each order of scattering corresponding to
quasi-free conditions. Quantum corrections are evaluated for double scattering
and are found to be large. Global agreement with the data is good.Comment: 30 pages, 12 figure
Monte Carlo simulation of baryon and lepton number violating processes at high energies
We report results obtained with the first complete event generator for
electroweak baryon and lepton number violating interactions at supercolliders.
We find that baryon number violation would be very difficult to establish, but
lepton number violation can be seen provided at least a few hundred L violating
events are available with good electron or muon identification in the energy
range 10 GeV to 1 TeV.Comment: 40 Pages uuencoded LaTeX (20 PostScript figures included),
Cavendish-HEP-93/6, CERN-TH.7090/9
Light controlled magnetoresistance and magnetic field controlled photoresistance in CoFe film deposited on BiFeO3
We present a magnetoresistive-photoresistive device based on the interaction
of a piezomagnetic CoFe thin film with a photostrictive BiFeO3 substrate that
undergoes light-induced strain. The magnitude of the resistance and
magnetoresistance in the CoFe film can be controlled by the wavelength of the
incident light on the BiFeO3. Moreover, a light-induced decrease in anisotropic
magnetoresistance is detected due to an additional magnetoelastic contribution
to magnetic anisotropy of the CoFe film. This effect may find applications in
photo-sensing systems, wavelength detectors and can possibly open a research
development in light-controlled magnetic switching properties for next
generation magnetoresistive memory devices.Comment: 5 pages, 4 figures, journal pape
Cavity spin optodynamics
The dynamics of a large quantum spin coupled parametrically to an optical
resonator is treated in analogy with the motion of a cantilever in cavity
optomechanics. New spin optodynamic phenonmena are predicted, such as
cavity-spin bistability, optodynamic spin-precession frequency shifts, coherent
amplification and damping of spin, and the spin optodynamic squeezing of light.Comment: 4 pages, 3 figure
Seabed Biodiversity Shifts Identify Climate Regimes: The 2011 Climate Regime Shift and Associated Cascades
Using search programs for a long-term SCUBA taxonomic database (3865 dives) for Strait of Georgia seabed sites, 1077 taxa were screened to select rare or highly abundant taxa and to present the data according to climate regime categories. Ocean Niño Index (ONI) climate regime shifts are defined here as the year of the end of the first La Niña closely paired with an El Niño by ≤2 months separation, where anomalies for both El Niño and La Niña exceed 1.0 on the ONI scale. For both rare and abundant taxa, patterns of increased or decreased abundance frequently correspond to years defining climate regimes. Cascading effects of climate regime shifts may occur via changes in community composition. The sea star wasting disease (SSWD) syndrome eliminated urchin predators so that urchins have decreased abundance of a kelp species that is nursery habitat for spot prawns. We conclude that 2011 was a climate regime shift. This 2011 regime shift coincided with loss of 11 seabed species in the Strait of Georgia, none of them at their southern range extreme
Optical bistability involving planar metamaterial with broken structural symmetry
We report on a bistable light transmission through a planar metamaterial
composed of a metal pattern of weakly asymmetric elements placed on a nonlinear
substrate. Such structure bears the Fano-like sharp resonance response of a
trapped-mode excitation. The feedback required for bistability is provided by
the coupling between the strong antiphased trapped-mode-resonance currents
excited on the metal elements and the intensity of inner field in the nonlinear
substrate.Comment: 4 pages, 4 figure
#Funeral and Instagram: death, social media, and platform vernacular
© 2014, © 2014 Taylor & Francis. This paper presents findings from a study of Instagram use and funerary practices that analysed photographs shared on public profiles tagged with ‘#funeral’. We found that the majority of images uploaded with the hashtag #funeral often communicated a person's emotional circumstances and affective context, and allowed them to reposition their funeral experience amongst wider networks of acquaintances, friends, and family. We argue that photo-sharing through Instagram echoes broader shifts in commemorative and memorialization practices, moving away from formal and institutionalized rituals to informal and personalized, vernacular practices. Finally, we consider how Instagram's ‘platform vernacular’ unfolds in relation to traditions and contexts of death, mourning, and memorialization. This research contributes to a broader understanding of how platform vernaculars are shaped through the logics of architecture and use. This research also directly contributes to the understanding of death and digital media by examining how social media is being mobilized in relation to death, the differences that different media platforms make, and the ways social media are increasingly entwined with the places, events, and rituals of mourning
A Search for Instantons at HERA
A search for QCD instanton (I) induced events in deep-inelastic scattering
(DIS) at HERA is presented in the kinematic range of low x and low Q^2. After
cutting into three characteristic variables for I-induced events yielding a
maximum suppression of standard DIS background to the 0.1% level while still
preserving 10% of the I-induced events, 549 data events are found while
363^{+22}_{-26} (CDM) and 435^{+36}_{-22} (MEPS) standard DIS events are
expected. More events than expected by the standard DIS Monte Carlo models are
found in the data. However, the systematic uncertainty between the two
different models is of the order of the expected signal, so that a discovery of
instantons can not be claimed. An outlook is given on the prospect to search
for QCD instanton events using a discriminant based on range searching in the
kinematical region Q^2\gtrsim100\GeV^2 where the I-theory makes safer
predictions and the QCD Monte Carlos are expected to better describe the
inclusive data.Comment: Invited talk given at the Ringberg Workshop on HERA Physics on June
19th, 2001 on behalf of the H1 collaboratio
Posthumous personhood and the affordances of digital media
© 2015 Taylor & Francis. This article identifies and outlines some of the more prominent ways that digital media can extend one’s personhood following death. We consider three examples: when the digital persona of the deceased continues to interact with the living through a human surrogate; the emergence of autonomous and semi-autonomous software enabling the dead to use social media to intervene in current events; and finally the operation of algorithmic presence services like Eterni.me, where artificial intelligence creates a re-enlivened form of the deceased. Situating these examples in relation to sociological, anthropological and cultural literature foundational to ideas of distributed personhood and posthumous symbolic immortality, we suggest that digital codes and computational texts stand as key sites for contemporary forms of ‘distributed personhood’, including posthumous personhood. We then extend this body of literature by examining how the discursive politics of social media contributes to a social and commercial context, which supports ongoing interactions with the dead online. Through this process, we suggest that the persona of the dead, which remains after bodily death, can continue to maintain meaningful posthumous relationships with the living, presenting a new perspective on how we interact with the dead through digital media
Exome Screening to Identify Loss-of-Function Mutations in the Rhesus Macaque for Development of Preclinical Models of Human Disease
BACKGROUND: Exome sequencing has been utilized to identify genetic variants associated with disease in humans. Identification of loss-of-function mutations with exome sequencing in rhesus macaques (Macaca mulatta) could lead to valuable animal models of genetic disease. Attempts have been made to identify variants in rhesus macaques by aligning exome data against the rheMac2 draft genome. However, such efforts have been impaired due to the incompleteness and annotation errors associated with rheMac2. We wished to determine whether aligning exome reads against our new, improved rhesus genome, MacaM, could be used to identify high impact, loss-of-function mutations in rhesus macaques that would be relevant to human disease.
RESULTS: We compared alignments of exome reads from four rhesus macaques, the reference animal and three unrelated animals, against rheMac2 and MacaM. Substantially more reads aligned against MacaM than rheMac2. We followed the Broad Institute\u27s Best Practice guidelines for variant discovery which utilizes the Genome Analysis Toolkit to identify high impact mutations. When rheMac2 was used as the reference genome, a large number of apparent false positives were identified. When MacaM was used as the reference genome, the number of false positives was greatly reduced. After examining the variant analyses conducted with MacaM as reference genome, we identified two putative loss-of-function mutations, in the heterozygous state, in genes related to human health. Sanger sequencing confirmed the presence of these mutations. We followed the transmission of one of these mutations (in the butyrylthiocholine gene) through three generations of rhesus macaques. Further, we demonstrated a functional decrease in butyrylthiocholinesterase activity similar to that observed in human heterozygotes with loss-of-function mutations in the same gene.
CONCLUSIONS: The new MacaM genome can be effectively utilized to identify loss-of-function mutations in rhesus macaques without generating a high level of false positives. In some cases, heterozygotes may be immediately useful as models of human disease. For diseases where homozygous mutants are needed, directed breeding of loss-of-function heterozygous animals could be used to create rhesus macaque models of human genetic disease. The approach we describe here could be applied to other mammals, but only if their genomes have been improved beyond draft status
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