1,469 research outputs found
Optimisation problems and replica symmetry breaking in finite connectivity spin-glasses
A formalism capable of handling the first step of hierarchical replica
symmetry breaking in finite-connectivity models is introduced. The emerging
order parameter is claimed to be a probability distribution over the space of
field distributions (or, equivalently magnetisation distributions) inside the
cluster of states. The approach is shown to coincide with the previous works in
the replica symmetric case and in the two limit cases m=0,1 where m is Parisi's
break-point. As an application to the study of optimization problems, the
ground-state properties of the random 3-Satisfiability problem are investigated
and we present a first RSB solution improving replica symmetric results.Comment: 16 pages Revtex file, 1 figure; amended version with two new
appendices; to be published in J.Phys.
Nanoparticles for bone tissue engineering
Tissue engineering (TE) envisions the creation of functional substitutes for damaged tissues through integrated solutions, where medical, biological, and engineering principles are combined. Bone regeneration is one of the areas in which designing a model that mimics all tissue properties is still a challenge. The hierarchical structure and high vascularization of bone hampers a TE approach, especially in large bone defects. Nanotechnology can open up a new era for TE, allowing the creation of nanostructures that are comparable in size to those appearing in natural bone. Therefore, nanoengineered systems are now able to more closely mimic the structures observed in naturally occurring systems, and it is also possible to combine several approaches - such as drug delivery and cell labeling - within a single system. This review aims to cover the most recent developments on the use of different nanoparticles for bone TE, with emphasis on their application for scaffolds improvement; drug and gene delivery carriers, and labeling techniques.This study was funded by QREN (ON.2 - NORTE-01-0124-FEDER-000018), as well as the European Union’s FP7 Programme under grant agreement number REGPOTCT2012-316331-POLARIS.
Sılvia Vieira was awarded an FCT PhD scholarship (SFRH/BD/102710/2014). The FCT distinction attributed to J.M.O. under the Investigator FCT program (IF/00423/2012 and IF/01285/2015) is also greatly acknowledged.info:eu-repo/semantics/publishedVersio
Development of a pyramidal magneto-optical trap for pressure sensing application
Here, we report the development and working of a compact rubidium (Rb) atom
magneto-optical trap (MOT) operated with a hollow pyramidal mirror and a single
laser beam. This type of compact MOT is suitable for developing portable
atom-optic devices, as it works with less number of optical components as
compared to conventional MOT setup. The application of this compact MOT setup
for pressure sensing has been demonstrated
High-Dimensional Similarity Search with Quantum-Assisted Variational Autoencoder
Recent progress in quantum algorithms and hardware indicates the potential
importance of quantum computing in the near future. However, finding suitable
application areas remains an active area of research. Quantum machine learning
is touted as a potential approach to demonstrate quantum advantage within both
the gate-model and the adiabatic schemes. For instance, the Quantum-assisted
Variational Autoencoder has been proposed as a quantum enhancement to the
discrete VAE. We extend on previous work and study the real-world applicability
of a QVAE by presenting a proof-of-concept for similarity search in large-scale
high-dimensional datasets. While exact and fast similarity search algorithms
are available for low dimensional datasets, scaling to high-dimensional data is
non-trivial. We show how to construct a space-efficient search index based on
the latent space representation of a QVAE. Our experiments show a correlation
between the Hamming distance in the embedded space and the Euclidean distance
in the original space on the Moderate Resolution Imaging Spectroradiometer
(MODIS) dataset. Further, we find real-world speedups compared to linear search
and demonstrate memory-efficient scaling to half a billion data points
A qualitative, grounded theory exploration of the determinants of self-care behavior among Indian patients with a lived experience of chronic heart failure
Prior reports have documented extremely poor adherence to evidence-based medications
among South Asian patients with established chronic cardiovascular diseases. Treatment
adherence is now considered a part of the ‘self-care’ process, the determinants of which
have not been adequately explored or explained among South Asian patients with chronic
heart failure (CHF). Our objective was to qualitatively ascertain the determinants of the selfcare process among Indian patients with a lived experience of heart failure
Amyloid β induces early changes in the ribosomal machinery, cytoskeletal organization and oxidative phosphorylation in retinal photoreceptor cells
Amyloid β (Aβ) accumulation and its aggregation is characteristic molecular feature of the development of Alzheimer’s disease (AD). More recently, Aβ has been suggested to be associated with retinal pathology associated with AD, glaucoma and drusen deposits in age related macular degeneration (AMD). In this study, we investigated the proteins and biochemical networks that are affected by Aβ in the 661 W photoreceptor cells in culture. Time and dose dependent effects of Aβ on the photoreceptor cells were determined utilizing tandem mass tag (TMT) labeling-based quantitative mass-spectrometric approach. Bioinformatic analysis of the data revealed concentration and time dependent effects of the Aβ peptide stimulation on various key biochemical pathways that might be involved in mediating the toxicity effects of the peptide. We identified increased Tau phosphorylation, GSK3β dysregulation and reduced cell viability in cells treated with Aβ in a dose and time dependent manner. This study has delineated for the first-time molecular networks in photoreceptor cells that are impacted early upon Aβ treatment and contrasted the findings with a longer-term treatment effect. Proteins associated with ribosomal machinery homeostasis, mitochondrial function and cytoskeletal organization were affected in the initial stages of Aβ exposure, which may provide key insights into AD effects on the photoreceptors and specific molecular changes induced by Aβ peptide
Hyperon weak radiative decays in chiral perturbation theory
We investigate the leading-order amplitudes for weak radiative decays of
hyperons in chiral perturbation theory. We consistently include contributions
from the next-to-leading order weak-interaction Lagrangian. It is shown that
due to these terms Hara's theorem is violated. The data for the decays of
charged hyperons can be easily accounted for. However, at this order in the
chiral expansion, the four amplitudes for the decays of neutral hyperons
satisfy relations which are in disagreement with the data. The asymmetry
parameters for all the decays can not be accounted for without higher-order
terms. We shortly comment on the effect of the 27-plet part of the weak
interaction.Comment: 8 pages of REVTeX and using macro-package "feynman.tex" (available at
http://xxx.lanl.gov/ftp/hep-ph/papers/macros) for the 2 figure
Randomized controlled trial of a good practice approach to treatment of childhood obesity in Malaysia: Malaysian childhood obesity treatment trial (MASCOT)
Context. Few randomized controlled trials (RCTs) of interventions for the treatment of childhood obesity have taken place outside the Western world. Aim. To test whether a good practice intervention for the treatment of childhood obesity would have a greater impact on weight status and other outcomes than a control condition in Kuala Lumpur, Malaysia. Methods. Assessor-blinded RCT of a treatment intervention in 107 obese 7- to 11-year olds. The intervention was relatively low intensity (8 hours contact over 26 weeks, group based), aiming to change child sedentary behavior, physical activity, and diet using behavior change counselling. Outcomes were measured at baseline and six months after the start of the intervention. Primary outcome was BMI z-score, other outcomes were weight change, health-related quality of life (Peds QL), objectively measured physical activity and sedentary behavior (Actigraph accelerometry over 5 days). Results. The intervention had no significant effect on BMI z score relative to control. Weight gain was reduced significantly in the intervention group compared to the control group (+1.5 kg vs. +3.5 kg, respectively, t-test p < 0.01). Changes in health-related quality of life and objectively measured physical activity and sedentary behavior favored the intervention group. Conclusions. Treatment was associated with reduced rate of weight gain, and improvements in physical activity and quality of life. More substantial benefits may require longer term and more intensive interventions which aim for more substantive lifestyle changes
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