3,170 research outputs found
Yang-Mills equation for stable Higgs sheaves
We establish a Kobayashi-Hitchin correspondence for the stable Higgs sheaves
on a compact Kaehler manifold. Using it, we also obtain a Kobayashi-Hitchin
correspondence for the stable Higgs G-sheaves, where G is any complex reductive
linear algebraic group
On Simulating Liouvillian Flow From Quantum Mechanics Via Wigner Functions
The interconnection between quantum mechanics and probabilistic classical
mechanics for a free relativistic particle is derived in terms of Wigner
functions (WF) for both Dirac and Klein-Gordon (K-G) equations. Construction of
WF is achieved by first defining a bilocal 4-current and then taking its
Fourier transform w.r.t. the relative 4-coordinate. The K-G and Proca cases
also lend themselves to a closely parallel treatment provided the Kemmer-
Duffin beta-matrix formalism is employed for the former. Calculation of WF is
carried out in a Lorentz-covariant fashion by standard `trace' techniques. The
results are compared with a recent derivation due to Bosanac.Comment: 9 pages, Latex; email: [email protected]
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Experimental evidence on promotion of electric and improved biomass cookstoves.
Improved cookstoves (ICS) can deliver "triple wins" by improving household health, local environments, and global climate. Yet their potential is in doubt because of low and slow diffusion, likely because of constraints imposed by differences in culture, geography, institutions, and missing markets. We offer insights about this challenge based on a multiyear, multiphase study with nearly 1,000 households in the Indian Himalayas. In phase I, we combined desk reviews, simulations, and focus groups to diagnose barriers to ICS adoption. In phase II, we implemented a set of pilots to simulate a mature market and designed an intervention that upgraded the supply chain (combining marketing and home delivery), provided rebates and financing to lower income and liquidity constraints, and allowed households a choice among ICS. In phase III, we used findings from these pilots to implement a field experiment to rigorously test whether this combination of upgraded supply and demand promotion stimulates adoption. The experiment showed that, compared with zero purchase in control villages, over half of intervention households bought an ICS, although demand was highly price-sensitive. Demand was at least twice as high for electric stoves relative to biomass ICS. Even among households that received a negligible price discount, the upgraded supply chain alone induced a 28 percentage-point increase in ICS ownership. Although the bundled intervention is resource-intensive, the full costs are lower than the social benefits of ICS promotion. Our findings suggest that market analysis, robust supply chains, and price discounts are critical for ICS diffusion
Ultrasonic Velocity and other Parameters in Sulphuric Acid-Sodium Hydroxide Solutions
Ultrasonic velocity, adiabatic compressibility and refractive index have been determined in aqueous sulphuric acid=sodium hydroxide mixtures at different concentrations. Variation of these parameters with composition of the mixture was studied with a view of fix the end points of neutralization
Optimal Cloning and Singlet Monogamy
The inability to produce two perfect copies of an unknown state is inherently
linked with the inability to produce maximal entanglement between multiple
spins. Despite this, there is no quantitative link between how much
entanglement can be generated between spins (known as monogamy), and how well
an unknown state can be cloned. This situation is remedied by giving a set of
sufficient conditions such that the optimal Completely Positive map can be
implemented as a teleportation operation into a standard, reference, state. The
case of arbitrary 1 to N asymmetric cloning of d-dimensional spins can then be
solved exactly, yielding the concept of `singlet monogamy'. The utility of this
relation is demonstrated by calculating properties of Heisenberg systems, and
contrasting them with the results from standard monogamy arguments.Comment: 4 pages, 1 figure. v2: conjecture upgraded to proof and generalized
to arbitrary local hilbert space dimensions. v3: published versio
HUNTINGTON’S DISEASE: CURRENT ADVANCES AND FUTURE PROSPECTS
Huntington’s disease is a neurodegenerative disease which is caused by dominantly inherited cytosine-adenine-guanine trinucleotide repeat expansion in the huntingtin gene of chromosome 4. Present survey reveals 2.7 per 100000 people are affected by huntington’s disease worldwide. The symptoms present with these patients are progressive motor, cognitive and psychiatric disorders. The early symptoms are chorea and loss of balance. This review aims to observe the present data available concerning huntington’s disease, symptoms, age of onset, risk factors, benefits of early diagnosis and genetic attribution. There is no cure for the disease. The article searched, selected and reviewed were from google scholar, medscape, NIH MedlinePlus, PubMed database using MeSH terms huntington’s disease, recent therapeutic advancement from 2003 to July 2021 with no language restriction and additional studies were included from the reference lists of relevant articles. The present review provides clinical features, diagnosis, symptomatic management and ongoing research. Hence this review will have an impact to create awareness for the society and researchers to find future treatment for Huntington’s disease
Concurrency-aware thread scheduling for high-level synthesis
When mapping C programs to hardware, high-level synthesis (HLS) tools seek to reorder instructions so they can be packed into as few clock cycles as possible. However, when synthesising multi-threaded C, instruction reordering is inhibited by the presence of atomic operations (‘atomics’), such as compare- and-swap. Atomics, the fundamental concurrency primitive in C, are the basis of more abstract concurrency mechanisms such as locks, and also of efficient lock-free data structures. Whether a particular atomic can be legally reordered within a thread can depend on the memory access patterns of other threads. Existing HLS tools that support atomics typically sched- ule each thread independently, and so must be conservative when optimising around atomics. Yet HLS tools are distinguished from conventional compilers by having the entire program available. Can this information be exploited to allow more reorderings within each thread, and hence to obtain more efficient schedules? In this work, we propose a global analysis that determines, for each thread, which pairs of instructions must not be reordered. Our analysis is sensitive to the C consistency mode of the atomics involved (e.g. relaxed, release, acquire, and sequentially- consistent). We have used the Alloy model checker to validate our analysis against the C language standard, and have implemented it in the LegUp HLS tool. An evaluation on several lock-free data structure benchmarks indicates that our analysis leads to a 1.6 × average global speedup
Decay of nuclear hyperpolarization in silicon microparticles
We investigate the low-field relaxation of nuclear hyperpolarization in
undoped and highly doped silicon microparticles at room temperature following
removal from high field. For nominally undoped particles, two relaxation time
scales are identified for ambient fields above 0.2 mT. The slower, T_1s, is
roughly independent of ambient field; the faster, T_1f, decreases with
increasing ambient field. A model in which nuclear spin relaxation occurs at
the particle surface via a two-electron mechanism is shown to be in good
agreement with the experimental data, particularly the field-independence of
T_1s. For boron-doped particles, a single relaxation time scale is observed.
This suggests that for doped particles, mobile carriers and bulk ionized
acceptor sites, rather than paramagnetic surface states, are the dominant
relaxation mechanisms. Relaxation times for the undoped particles are not
affected by tumbling in a liquid solution.Comment: related papers at http://marcuslab.harvard.ed
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