In this paper, we analyze some of the main properties of a double base number system, using bases 2 and 3; in particular, we emphasize the sparseness of the representation. A simple geometric ...interpretation allows an efficient implementation of the basic arithmetic operations and we introduce an index calculus for logarithmic-like arithmetic with considerable hardware reductions in lookup table size. We discuss the application of this number system in the area of digital signal processing; we illustrate the discussion with examples of finite impulse response filtering.
Neuroplasticity may play a critical role in developing robust, naturally controlled neuroprostheses. This learning, however, is sensitive to system changes such as the neural activity used for ...control. The ultimate utility of neuroplasticity in real-world neuroprostheses is thus unclear. Adaptive decoding methods hold promise for improving neuroprosthetic performance in nonstationary systems. Here, we explore the use of decoder adaptation to shape neuroplasticity in two scenarios relevant for real-world neuroprostheses: nonstationary recordings of neural activity and changes in control context. Nonhuman primates learned to control a cursor to perform a reaching task using semistationary neural activity in two contexts: with and without simultaneous arm movements. Decoder adaptation was used to improve initial performance and compensate for changes in neural recordings. We show that beneficial neuroplasticity can occur alongside decoder adaptation, yielding performance improvements, skill retention, and resistance to interference from native motor networks. These results highlight the utility of neuroplasticity for real-world neuroprostheses.
•Combined neural and decoder adaptation can yield skillful neuroprosthetic control•Decoder adaptation shapes neural representations of neuroprosthetic control•Learning yields changes in the timing of neural recruitment•Neuroprosthetic skill formation reduces interference from native motor networks
Orsborn et al. demonstrate that neural and decoder adaptation can be combined to achieve and maintain skillful neuroprosthetic control despite changes in neural recordings and control contexts. They show that these adaptation mechanisms interact to shape long-term neuroprosthetic performance.
The multidimensional logarithmic number system (MDLNS), which has similar properties to the classical logarithmic number system (LNS), provides more degrees of freedom than the LNS by virtue of ...having two, or more, orthogonal bases and has the ability to use multiple MDLNS components, or digits. Unlike the LNS, there is no monotonic relationship between standard binary representations and MDLNS representations. Using look-up tables (LUTs) to perform the mapping function can be unrealistic for hardware implementations when large binary ranges or multiple digits are used. This work proposes a novel range-addressable technique for using look-up tables that allows efficient conversion from binary-to-single or multidigit MDLNS with varying accuracies, depending on the selected implementation.
Information-based distortion methods have been used successfully in the analysis of neural coding problems. These approaches allow the discovery of neural symbols and the corresponding stimulus space ...of a neuron or neural ensemble quantitatively, while making few assumptions about the nature of either the code or of relevant stimulus features. The neural codebook is derived by quantizing sensory stimuli and neural responses into a small set of clusters, and optimizing the quantization to minimize an information distortion function. The method of annealing has been used to solve the corresponding high-dimensional nonlinear optimization problem. The annealing solutions undergo a series of bifurcations, which we study using bifurcation theory in the presence of symmetries. In this contribution we describe these symmetry breaking bifurcations in detail, and indicate some of the consequences of the form of the bifurcations. In particular, we show that the annealing solutions break symmetry at pitchfork bifurcations, and that subcritical branches can exist. Thus, at a subcritical bifurcation, there are local information distortion solutions which are not found by the method of annealing. Since the annealing procedure is guaranteed to converge to a local solution eventually, the subcritical branch must turn and become optimal at some later saddle-node bifurcation, which we have shown occur generically for this class of problems. This implies that the rate distortion curve, while convex for noninformation-based distortion measures, is not convex for information-based distortion methods.
Background.
Intensive physical exertion is one of the stress-factors leading to the decrease of non-specific resistance of the body, significant increase in oxygen consumption followed by activation ...of the lipid peroxidation and decrease of endogenic antioxidant system efficacy.
The aim
of the present study was to evaluate the influence of the complex plant remedy on exercise tolerance of laboratory animals and to reveal mechanisms increasing physical endurance.
Materials and methods.
The experiments were carried out on white Wistar rats weighing 190-220 g. The physical endurance of the animals was estimated by recording time of weighted swimming to complete exhaustion in the pool. The weighting was 7 % of the body mass. The water solution of the dry extract derived from five medicinal plants was introduced intragastrically to the animals of the experimental group at the dose of 100 mg/kg in the volume of 10 ml/kg for 7 days (once a day), an hour before testing. The content of ATP, lactic acid and pyruvic acid were determined in the skeletal muscle homogenate; glycogen was determined in the liver homogenate; in the blood serum there was estimated concentration of malonic dialdehyde, the activity of catalase; the concentration of reduced glutathione was determined in the whole blood and the activity of superoxide dismutase was estimated in erythrocytes.
Conclusion.
The course introduction of the complex plant remedy to rats results in resilience to intensive physical exertion due to optimization of energy metabolism, inhibition of free-radical biomacromolecule oxidation processes and increase in endogenic antioxidant system activity.
Generally the anatomy of muscles is rather complex, and the fibres have various inclination angles within the muscles. We suggest a fast and reliable way to calculate extracellular potentials ...produced at a point or rectangular plate electrode by a muscle fibre of finite length with an arbitrary inclination. A muscle fibre was considered to be a linear timeshift-invariant system of potential generation. Then, similar to the fibre without inclination, the extracellular potential produced by an inclined fibre was represented as the output signal of the system; it was calculated as the convolution of the input signal and impulse response. Irrespective of the inclination, the input signal of the system was the first temporal derivative of the intracellular action potential. The impulse response of the system differed for the fibres with inclination. This required a new method of analytical integration over the rectangular electrode area. The approach provides a chance to simulate and analyze motor unit potentials or F-, H- or M-responses produced by muscles of complicated anatomy (circum-pennate or complex pennate type) at electrodes of actual size and location in normals and patients with neuro-muscular disorders.
In this paper, we propose new algorithms for multiple modular exponentiation operations. The major aim of these algorithms is to speed up the performance of some cryptographic protocols based on ...multiexponentiation. Our new algorithms are based on binary-like complex arithmetic, introduced by K. Pekmestzi (1989) and generalized in this paper.
Improved resistive plate chambers for HL-LHC upgrade of CMS Samalan, A.; Thiel, M.; Asilar, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2024, Letnik:
1060, Številka:
C
Journal Article
An abrupt drowning of the Black Sea shelf Ryan, William B.F.; Pitman, Walter C.; Major, Candace O. ...
Marine geology,
April 1997, 1997-04-00, 19970401, Letnik:
138, Številka:
1-2
Journal Article
Recenzirano
Odprti dostop
During latest Quaternary glaciation, the Black Sea became a giant freshwater lake. The surface of this lake drew down to levels more than 100 m below its outlet. When the Mediterranean rose to the ...Bosporus sill at 7,150 yr BP11Unless otherwise noted, all dates reported are raw carbon-14 ages before reservoir corrections (460 yr) and thus are compatible with previously published dates., saltwater poured through this spillway to refill the lake and submerge, catastrophically, more than 100,000 km2 of its exposed continental shelf. The permanent drowning of a vast terrestrial landscape may possibly have accelerated the dispersal of early neolithic foragers and farmers into the interior of Europe at that time.
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