791 research outputs found
Effect of drought stress on pea nutritional quality
info:eu-repo/semantics/publishedVersio
Search-and-replace editing for personal photo collections
We propose a new system for editing personal photo collections, inspired by search-and-replace editing for text. In our system, local edits specified by the user in a single photo (e.g., using the “clone brush” tool) can be propagated automatically to other photos in the same collection, by matching the edited region across photos. To achieve this, we build on tools from computer vision for image matching. Our experimental results on real photo collections demonstrate the feasibility and potential benefits of our approach.Natural Sciences and Engineering Research Council of Canada Postdoctoral FellowshipMassachusetts Institute of Technology. Undergraduate Research Opportunities ProgramNational Science Foundation (U.S.) (CAREER award 0447561)T-Party ProjectUnited States. National Geospatial-Intelligence Agency (NGA NEGI-1582- 04-0004)United States. Office of Naval Research. Multidisciplinary University Research Initiative (Grant N00014-06-1-0734)Microsoft ResearchAlfred P. Sloan Foundatio
The genetic basis and adult reproductive consequences of developmental thermal plasticity
Increasing temperature and thermal variability generate profound selection on populations. Given the fast rate of environmental change, understanding the role of plasticity and genetic adaptation in response to increasing temperatures is critical. This may be especially true for thermal effects on reproductive traits in which thermal fertility limits at high temperatures may be lower than for survival traits. Consequences of changing environments during development on adult phenotypes may be particularly problematic for core traits such as reproduction that begin early in development. Here we examine the consequences of developmental thermal plasticity on subsequent adult reproductive traits and its genetic basis.
We used a panel of Drosophila melanogaster (the Drosophila Genetic Reference Panel; DGRP) in which male fertility performance was previously defined as either showing relatively little (status = ‘high’-performing lines) or substantial (‘low’-performing lines) decline when exposed to increasing developmental temperatures. We used a thermal reaction norm approach to quantify variation in the consequences of developmental thermal plasticity on multiple adult reproductive traits, including sex-specific responses, and to identify candidate genes underlying such variation.
Developmental thermal stress impacted the means and thermal reaction norms of all reproductive traits except offspring sex ratio. Mating success declined as temperature increased with no difference between high and low lines, whereas increasing temperature resulted in declines for both male and female fertility and productivity but depended on line status. Fertility and offspring number were positively correlated within and between the sexes across lines, but males were more affected than females.
We identified 933 SNPs with significant evolved genetic differentiation between high and low lines. In all, 54 of these lie within genomic windows of overall high differentiation, have significant effects of genotype on the male thermal reaction norm for productivity and are associated with 16 genes enriched for phenotypes affecting reproduction, stress responses and autophagy in Drosophila and other organisms.
Our results illustrate considerable plasticity in male thermal limits on several reproductive traits following development at high temperature, and we identify differentiated loci with relevant phenotypic effects that may contribute to this population variation. While our work is on a single population, phenotypic results align with an increasing number of studies demonstrating the potential for stronger selection of thermal stress on reproductive traits, particularly in males. Such large fitness costs may have both short- and long-term consequences for the evolution of populations in response to a warming world.info:eu-repo/semantics/publishedVersio
Mitigating Gender Bias in Machine Learning Data Sets
Artificial Intelligence has the capacity to amplify and perpetuate societal
biases and presents profound ethical implications for society. Gender bias has
been identified in the context of employment advertising and recruitment tools,
due to their reliance on underlying language processing and recommendation
algorithms. Attempts to address such issues have involved testing learned
associations, integrating concepts of fairness to machine learning and
performing more rigorous analysis of training data. Mitigating bias when
algorithms are trained on textual data is particularly challenging given the
complex way gender ideology is embedded in language. This paper proposes a
framework for the identification of gender bias in training data for machine
learning.The work draws upon gender theory and sociolinguistics to
systematically indicate levels of bias in textual training data and associated
neural word embedding models, thus highlighting pathways for both removing bias
from training data and critically assessing its impact.Comment: 10 pages, 5 figures, 5 Tables, Presented as Bias2020 workshop (as
part of the ECIR Conference) - http://bias.disim.univaq.i
Diffusion and viscosity in a supercooled polydisperse system
We have carried out extensive molecular dynamics simulations of a supercooled
polydisperse Lennard-Jones liquid with large variations in temperature at a
fixed pressure. The particles in the system are considered to be polydisperse
both in size and mass. The temperature dependence of the dynamical properties
such as the viscosity () and the self-diffusion coefficients () of
different size particles is studied. Both viscosity and diffusion coefficients
show super-Arrhenius temperature dependence and fit well to the well-known
Vogel-Fulcher-Tammann (VFT) equation. Within the temperature range
investigated, the value of the Angell's fragility parameter (D )
classifies the present system into a strongly fragile liquid. The critical
temperature for diffusion () increases with the size of the
particles. The critical temperature for viscosity () is larger than
that for the diffusion and a sizeable deviations appear for the smaller size
particles implying a decoupling of translational diffusion from viscosity in
deeply supercooled liquid. Indeed, the diffusion shows markedly non-Stokesian
behavior at low temperatures where a highly nonlinear dependence on size is
observed. An inspection of the trajectories of the particles shows that at low
temperatures the motions of both the smallest and largest size particles are
discontinuous (jump-type). However, the crossover from continuous Brownian to
large length hopping motion takes place at shorter time scales for the smaller
size particles.Comment: Revtex4, 7 pages, 8 figure
Molecular dynamics in shape space and femtosecond vibrational spectroscopy of metal clusters
We introduce a method of molecular dynamics in shape space aimed at metal
clusters. The ionic degrees of freedom are described via a dynamically
deformable jellium with inertia parameters derived from an incompressible,
irrotational flow. The shell correction method is used to calculate the
electronic potential energy surface underlying the dynamics. Our finite
temperature simulations of Ag_14 and its ions, following the negative to
neutral to positive scheme, demonstrate the potential of pump and probe
ultrashort laser pulses as a spectroscopy of cluster shape vibrations.Comment: Latex/Revtex, 4 pages with 3 Postscript figure
Kapitza Resistance between Few-Layer Graphene and Water: Liquid Layering Effects
The Kapitza resistance (RK) between few-layer graphene (FLG) and water was studied using molecular dynamics simulations. The R_K was found to depend on the number of the layers in the FLG though, surprisingly, not on the water block thickness. This distinct size dependence is attributed to the large difference in the phonon mean free path between the FLG and water. Remarkably, R_K is strongly dependent on the layering of water adjacent to the FLG, exhibiting an inverse proportionality relationship to the peak density of the first water layer, which is consistent with better acoustic phonon matching between FLG and water. These findings suggest novel ways to engineer the thermal transport properties of solid–liquid interfaces by controlling and regulating the liquid layering at the interface
Pathway to the PiezoElectronic Transduction Logic Device
The information age challenges computer technology to process an
exponentially increasing computational load on a limited energy budget - a
requirement that demands an exponential reduction in energy per operation. In
digital logic circuits, the switching energy of present FET devices is
intimately connected with the switching voltage, and can no longer be lowered
sufficiently, limiting the ability of current technology to address the
challenge. Quantum computing offers a leap forward in capability, but a clear
advantage requires algorithms presently developed for only a small set of
applications. Therefore, a new, general purpose, classical technology based on
a different paradigm is needed to meet the ever increasing demand for data
processing.Comment: in Nano Letters (2015
Controlling the energy flow in nonlinear lattices: a model for a thermal rectifier
We address the problem of heat conduction in 1-D nonlinear chains; we show
that, acting on the parameter which controls the strength of the on site
potential inside a segment of the chain, we induce a transition from conducting
to insulating behavior in the whole system. Quite remarkably, the same
transition can be observed by increasing the temperatures of the thermal baths
at both ends of the chain by the same amount. The control of heat conduction by
nonlinearity opens the possibility to propose new devices such as a thermal
rectifier.Comment: 4 pages with figures included. Phys. Rev. Lett., to be published
(Ref. [10] corrected
CSP alpha reduces aggregates and rescues striatal dopamine release in alpha-synuclein transgenic mice
alpha-Synuclein aggregation at the synapse is an early event in Parkinson's disease and is associated with impaired striatal synaptic function and dopaminergic neuronal death. The cysteine string protein (CSP alpha) and alpha-synuclein have partially overlapping roles in maintaining synaptic function and mutations in each cause neurodegenerative diseases. CSP alpha is a member of the DNAJ/HSP40 family of co-chaperones and like alpha-synuclein, chaperones the SNARE complex assembly and controls neurotransmitter release. alpha-Synuclein can rescue neurodegeneration in CSP alpha KO mice. However, whether alpha-synuclein aggregation alters CSP alpha expression and function is unknown. Here we show that alpha-synuclein aggregation at the synapse is associated with a decrease in synaptic CSP alpha and a reduction in the complexes that CSP alpha forms with HSC70 and STG alpha. We further show that viral delivery of CSP alpha rescues in uitro the impaired vesicle recycling in PC12 cells with alpha-synuclein aggregates and in uiuo reduces synaptic alpha-synuclein aggregates increasing monomeric alpha-synuclein and restoring normal dopamine release in 1-120h alpha Syn mice. These novel findings reveal a mechanism by which alpha-synuclein aggregation alters CSP alpha at the synapse, and show that CSP alpha rescues alpha-synuclein aggregation-related phenotype in 1-120h alpha Syn mice similar to the effect of alpha-synuclein in CSP alpha KO mice. These results implicate CSP alpha as a potential therapeutic target for the treatment of earlystage Parkinson's disease
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