135 research outputs found
Is the incidence of dementia declining?
No full textAction on preventative health could lower the risk of dementia for future generations, argues this report.
Executive summary
The world-wide projections of the prevalence of dementia in the coming decades have been a source of great concern to health systems and societies around the world. The World Alzheimer Report 2010 estimated that there were 36 million people with dementia in 2010, with an expected doubling every 20 years to nearly 115 million in 2050. These sobering figures are based on assumptions that the age-adjusted prevalence of dementia would remain constant and the population would continue to age at the current rate.
The assumption that the incidence of dementia will remain stable is now being put into question. There is emerging evidence to suggest that the incidence of dementia in older individuals may be declining. It appears that this change may be recent and has possibly occurred only in the last one to two decades. It may also be restricted so far to high income countries, although data from low and middle income countries are lacking.
The reasons for this change are not understood, but education, more stimulating environments and better control of vascular risk factors may have contributed. The data are still preliminary and more studies are needed to establish the extent of this change and understand its causes. It should be noted that the decline is not large enough to offset the increase in prevalence of dementia due to the ageing of the population and therefore investment and efforts to develop better treatments and care for people with dementia need to continue.
The fact that dementia rates are malleable is an encouraging finding but the reduction cannot be taken for granted as gains in population health can easily be lost if societies do not remain vigilant and continually proactive. These preliminary findings provide a strong argument for large scale Government investment in dementia-prevention strategies, which should start from early life
Sachdev–Ye–Kitaev model as Liouville quantum mechanics
No full textAbstractWe show that the proper inclusion of soft reparameterization modes in the Sachdev–Ye–Kitaev model of N randomly interacting Majorana fermions reduces its long-time behavior to that of Liouville quantum mechanics. As a result, all zero temperature correlation functions decay with the universal exponent ∝τ−3/2 for times larger than the inverse single particle level spacing τ≫NlnN. In the particular case of the single particle Green function this behavior is manifestation of the zero-bias anomaly, or scaling in energy as ϵ1/2. We also present exact diagonalization study supporting our conclusions
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Algorithms and Architectures for Quantum Simulation with Neutral-atom Arrays
No full textFast and scalable quantum simulations promise to revolutionize our understanding of complex quantum systems,
In this thesis, we primarily aim to develop algorithms and architectures for leveraging programmable quantum devices, to model complex physical phenomena. As quantum computers can natively capture superposition and entanglement, two key attributes which are challenging for classical computers to accurately model, this approach promises significant benefits in the long run.
We focus primarily on neutral-atom arrays, an emerging experimental platform, although many of our results apply more generally as well. The work is structured into three phases, each progressively advancing the complexity and control of considered experimental hardware, and in parallel the importance and applicability of the considered quantum simulations.
In the first phase (Chapters 1–3), we address the challenge of programming and controlling quantum many-body systems through analog techniques. Analog quantum simulation utilizes continuous control parameters to engineer desired quantum states and dynamics. Chapter 1 introduces novel methods for steering entanglement using quantum many-body scars, harnessing special strongly-interacting dynamics to manipulate quantum entanglement robustly. Chapter 2 advances this approach by showing how Floquet engineering can be used to systematically generate interactions, and how this enables sophisticated control over entanglement and access to novel quantum phases. Chapter 3 integrates these developments into a general framework for programming Hamiltonians into analog quantum simulators with time-reversal capabilities, illustrating the power of programmable analog strategies for simulations of lattice gauge theories.
The second phase (Chapters 4–6) shifts focus to topologically ordered quantum states, known for their exotic long-range entanglement and fundamental significance in condensed matter physics and quantum computation. Chapter 4 presents strategies to enhance the experimental detection and verification of topological order using ideas from the renormalization group. The procedure we develop, order parameters dressed by local quantum error correction, significantly improve the practical observability of these delicate quantum phases. In Chapters 5 and 6, we explore novel techniques for realizing topological phases, by exploiting newly developed experimental capabilities, notably atom reconfiguration, to achieve precise digital control. In particular, we show how to engineer chiral Floquet spin liquids - exotic quantum phases exhibiting robust quantum coherence and non-Abelian excitations — as well as simulations of topological fermionic matter. These advancements not only illuminate foundational physics but also bridge towards robust quantum error correction schemes.
The final phase (Chapters 7 and 8) expands the techniques developed thus far towards the simulation of increasingly complex physical systems relevant to chemistry and materials science. Chapter 7 discusses a general framework for digital quantum simulation of effective spin models, prevalent in condensed matter physics, introducing crucial techniques for engineering and characterizing these Hamiltonians. Chapter 8 extends these insights by proving that fermionic quantum systems, essential for realistic simulations of electronic structures in molecules and materials, can be efficiently encoded into qubits. This advance significantly reduces computational complexity and opens pathways for genuine quantum simulations of chemical systems.
Collectively, these contributions represent substantial progress towards practical quantum simulation with neutral-atom quantum processors, laying critical foundations for future applications in physics, chemistry, and quantum information science.Physic
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Cognitive leisure activities, but not watching TV, for future brain benefits
No full textResponse of DNA molecules to external fields: Electric and hydrodynamic
No full textCasimir PhD Series: 2020-03ChemE/Product and Process Engineerin
Novel mutation in the RNASEH1 gene in a chronic progressive external ophthalmoplegia patient
No full textProgrammable techniques for cell stability test and debug in embedded SRAMs Programmable Techniques for Cell Stability Test and Debug in Embedded SRAMs
No full textCitation for published version (APA): Pavlov, A., Sachdev, M., Pineda de Gyvez, J., & Azimane, M. (2005) Please check the document version of this publication: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement: www.tue.nl/taverne Take down policy If you believe that this document breaches copyright please contact us at: [email protected] providing details and we will investigate your claim
Total Anterior Staphyloma Secondary to Acanthamoeba Keratitis.
No full textABSTRACT
There are very few published cases of total anterior staphyloma, all of which have been reported as secondary to fungal keratitis. This study reports the clinical and histopathological findings and subsequent management of a 27-year-old healthy female patient who developed total anterior staphyloma after poor compliance with treatment for clinically diagnosed acanthamoeba keratitis. She underwent a successful evisceration with good long-term results. This case highlights that total anterior staphyloma may also result from untreated keratitis which is not fungal in origin. In cases of fungal and acanthamoeba keratitis, patient compliance with both treatment and follow-up is paramount to avoid vision-threatening sequelae that present significant challenges in their management
Ultrapotent and broad neutralization of SARS-CoV-2 variants by modular, tetravalent, bi-paratopic antibodies
No full textNeutralizing antibodies (nAbs) that target the SARS-CoV-2 spike protein have received emergency use approval for treatment of COVID-19. However, with the emergence of variants of concern, there is a need for new treatment options. We report a format that enables modular assembly of bi-paratopic tetravalent nAbs with antigen-binding sites from two distinct nAbs. The tetravalent nAb purifies in high yield and exhibits biophysical characteristics that are comparable to those of clinically used therapeutic antibodies. The tetravalent nAb binds to the spike protein trimer at least 100-fold more tightly than bivalent IgGs (apparent K(D) < 1 pM) and neutralizes a broad array of SARS-CoV-2 pseudoviruses, chimeric viruses, and authentic viral variants with high potency. Together, these results establish the tetravalent diabody-Fc-Fab as a robust, modular platform for rapid production of drug-grade nAbs with potencies and breadth of coverage that greatly exceed those of conventional bivalent IgGs
Colloquium:Order and quantum phase transitions in the cuprate superconductors
No full textIt is now widely accepted that the cuprate superconductors are characterized by the same long-range order as that present in the Bardeen-Cooper-Schrieffer (BCS) theory: that associated with the condensation of Cooper pairs. The author argues that many physical properties of the cuprates require interplay with additional order parameters associated with a proximate Mott insulator. A classification of Mott insulators in two dimensions is proposed. Experimental evidence so far shows that the class appropriate to the cuprates has collinear spin correlations, bond order, and confinement of neutral, spin S = 1/2 excitations. Proximity to second-order quantum phase tran-sitions associated with these orders, and with the pairing order of BCS, has led to systematic predictions for many physical properties. In this context the author reviews the results of re-cent neutron scattering, fluxoid detection, nuclear magnetic resonance, and scanning tunnellin
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