1,597 research outputs found
Verifying proofs in constant depth
In this paper we initiate the study of proof systems where verification of proofs proceeds by NC circuits. We investigate the question which languages admit proof systems in this very restricted model. Formulated alternatively, we ask which languages can be enumerated by NC functions. Our results show that the answer to this problem is not determined by the complexity of the language. On the one hand, we construct NC proof systems for a variety of languages ranging from regular to NP-complete. On the other hand, we show by combinatorial methods that even easy regular languages such as Exact-OR do not admit NC proof systems. We also present a general construction of proof systems for regular languages with strongly connected NFA's
Adaptive multibeam antennas for spacelab. Phase A: Feasibility study
The feasibility was studied of using adaptive multibeam multi-frequency antennas on the spacelab, and to define the experiment configuration and program plan needed for a demonstration to prove the concept. Three applications missions were selected, and requirements were defined for an L band communications experiment, an L band radiometer experiment, and a Ku band communications experiment. Reflector, passive lens, and phased array antenna systems were considered, and the Adaptive Multibeam Phased Array (AMPA) was chosen. Array configuration and beamforming network tradeoffs resulted in a single 3m x 3m L band array with 576 elements for high radiometer beam efficiency. Separate 0.4m x 0.4 m arrays are used to transmit and receive at Ku band with either 576 elements or thinned apertures. Each array has two independently steerable 5 deg beams, which are adaptively controlled
Second quantisation for skew convolution products of infinitely divisible measures
Suppose and are infinitely divisible Radon measures
on real Banach spaces and , respectively and let be a Borel measurable mapping so that for some Radon probability measure on . Extending
previous results for the Gaussian and the Poissonian case, we study the problem
of representing the `transition operator' given by as the second quantisation of a contraction operator acting
between suitably chosen `reproducing kernel Hilbert spaces' associated with
and .Comment: Some typos have been corrected. To appear in IDAQ
Alleyne on the Ground: Factfinding that Limits Eligibility for Probation or Parole Release
This article addresses the impact of Alleyne v. United States on statutes that restrict an offenderās eligibility for release on parole or probation. Alleyne is the latest of several Supreme Court decisions applying the rule announced in the Courtās 2000 ruling, Apprendi v. New Jersey. To apply Alleyne, courts must for the first time determine what constitutes a minimum sentence and when that minimum is mandatory. These questions have proven particularly challenging in states that authorize indeterminate sentences, when statutes that delay the timing of eligibility for release are keyed to judicial findings at sentencing. The same questions also arise, in both determinate and indeterminate sentencing jurisdictions, under statutes that limit the option of imposing either probation or a suspended sentence upon judicial fact finding. In this Article, we argue that Alleyne invalidates such statutes. We provide analyses that litigants and judges might find useful as these Alleyne challenges make their way through the courts, and offer a menu of options for state lawmakers who would prefer to amend their sentencing law proactively in order to minimize disruption of their criminal justice systems
Anomalous Processes with General Waiting Times: Functionals and Multipoint Structure
Many transport processes in nature exhibit anomalous diffusive properties
with non-trivial scaling of the mean square displacement, e.g., diffusion of
cells or of biomolecules inside the cell nucleus, where typically a crossover
between different scaling regimes appears over time. Here, we investigate a
class of anomalous diffusion processes that is able to capture such complex
dynamics by virtue of a general waiting time distribution. We obtain a complete
characterization of such generalized anomalous processes, including their
functionals and multi-point structure, using a representation in terms of a
normal diffusive process plus a stochastic time change. In particular, we
derive analytical closed form expressions for the two-point correlation
functions, which can be readily compared with experimental data.Comment: Accepted in Phys. Rev. Let
The impact of coping strategies of cancer caregivers on psychophysiological outcomes: an integrative review
A growing number of studies have explored the psychosocial burden experienced by cancer caregivers, but less attention has been given to the psychophysiological impact of caregiving and the impact of caregivers' coping strategies on this association. This paper reviews existing research on the processes underlying distress experienced by cancer caregivers, with a specific focus on the role of coping strategies on psychophysiological correlates of burden
A functional non-central limit theorem for jump-diffusions with periodic coefficients driven by stable Levy-noise
We prove a functional non-central limit theorem for jump-diffusions with
periodic coefficients driven by strictly stable Levy-processes with stability
index bigger than one. The limit process turns out to be a strictly stable Levy
process with an averaged jump-measure. Unlike in the situation where the
diffusion is driven by Brownian motion, there is no drift related enhancement
of diffusivity.Comment: Accepted to Journal of Theoretical Probabilit
Metronidazole in the Prophylaxis and treatment of Anaerobic Infection
The influence of prophylactic metronidazole on vaginal
carriage rates of anaerobes and the development of postoperative
anaerobic infection was studied in 104 women
who underwent abdominal hysterectomy. Metronidazole
prophylaxis in 54 patients led to a decrease in the anaerobe
vaginal carriage rate from 65% pre-operatively to
17% and 28% on the 3rd and 7th postoperative days respectively.
In the control group (50 patients) no significant
decrease in anaerobe yield was noted, corresponding percentages
being 72%, 64%, and 74%. Postoperative infection
occurred in 36 patients (28 controls; 8 on prophylactic
metronidazole). Wound swabs from all 8 patients in
the latter group yielded aerobes, and in 1 patient mixed
infection (aerobes/anaerobes) occurred. In 7 of these
patients (including the patient with mixed infection), the
infection resolved spontaneously, while the 8th patient
responded to therapy with metronidazole, kanamycin and
ampicillin. In the control patients, 21 cases of postoperative
wound infection and 4 of vault infection were seen;
wound swabs from patients in the former group yielded
aerobes in only 6 cases, and mixed growth of aerobes/
anaerobes in 10 cases. Postoperative wound/vault infections
in control patients cleared spontaneously in 18 cases
and responded to imidazole therapy, with or without ampicillin
and kanamycin, in 7 cases.Web of Scienc
Transition Densities and Traces for Invariant Feller Processes on Compact Symmetric Spaces
We find necessary and sufficient conditions for a finite Kābiāinvariant
measure on a compact Gelfand pair (G, K) to have a squareāintegrable
density. For convolution semigroups, this is equivalent to having a
continuous density in positive time. When (G, K) is a compact Riemannian
symmetric pair, we study the induced transition density for
Gāinvariant Feller processes on the symmetric space X = G/K. These
are obtained as projections of Kābiāinvariant LĀ“evy processes on G,
whose laws form a convolution semigroup. We obtain a Fourier series
expansion for the density, in terms of spherical functions, where the
spectrum is described by Gangolliās LĀ“evyāKhintchine formula. The
density of returns to any given point on X is given by the trace of
the transition semigroup, and for subordinated Brownian motion, we
can calculate the short time asymptotics of this quantity using recent
work of BaĖnuelos and Baudoin. In the case of the sphere, there is an
interesting connection with the FunkāHecke theorem
Stochastic Calculus for a Time-changed Semimartingale and the Associated Stochastic Differential Equations
It is shown that under a certain condition on a semimartingale and a
time-change, any stochastic integral driven by the time-changed semimartingale
is a time-changed stochastic integral driven by the original semimartingale. As
a direct consequence, a specialized form of the Ito formula is derived. When a
standard Brownian motion is the original semimartingale, classical Ito
stochastic differential equations driven by the Brownian motion with drift
extend to a larger class of stochastic differential equations involving a
time-change with continuous paths. A form of the general solution of linear
equations in this new class is established, followed by consideration of some
examples analogous to the classical equations. Through these examples, each
coefficient of the stochastic differential equations in the new class is given
meaning. The new feature is the coexistence of a usual drift term along with a
term related to the time-change.Comment: 27 pages; typos correcte
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