Temporal structure in neuronal activity during working memory in Macaque parietal cortex

A number of cortical structures are reported to have elevated single unit firing rates sustained throughout the memory period of a working memory task. How the nervous system forms and maintains these memories is unknown but reverberating neuronal network activity is thought to be important. We studied the temporal structure of single unit (SU) activity and simultaneously recorded local field potential (LFP) activity from area LIP in the inferior parietal lobe of two awake macaques during a memory-saccade task. Using multitaper techniques for spectral analysis, which play an important role in obtaining the present results, we find elevations in spectral power in a 50--90 Hz (gamma) frequency band during the memory period in both SU and LFP activity. The activity is tuned to the direction of the saccade providing evidence for temporal structure that codes for movement plans during working memory. We also find SU and LFP activity are coherent during the memory period in the 50--90 Hz gamma band and no consistent relation is present during simple fixation. Finally, we find organized LFP activity in a 15--25 Hz frequency band that may be related to movement execution and preparatory aspects of the task. Neuronal activity could be used to control a neural prosthesis but SU activity can be hard to isolate with cortical implants. As the LFP is easier to acquire than SU activity, our finding of rich temporal structure in LFP activity related to movement planning and execution may accelerate the development of this medical application.Comment: Originally submitted to the neuro-sys archive which was never publicly announced (was 0005002

Markov-Yukawa Transversality On Covariant Null-Plane: Baryon Form Factor And Magnetic Moments

The baryon-$qqq$ vertex function governed by the Markov-Yukawa Transversality Principle ($MYTP$), is formulated via the Covariant Null-Plane Ansatz ($CNPA$) as a 3-body generalization of the corresponding $q{\bar q}$ problem, and employed to calculate the proton e.m. form factor and baryon octet magnetic moments.The e.m. coupling scheme is specified by letting the e.m. field interact by turn with the `spectator' while the two interacting quarks fold back into the baryon. The $S_3$ symmetry of the matrix element is preserved in all d.o.f.'s together. The $CNPA$ formulation ensures, as in the $q{\bar q}$ case, that the loop integral is free from the Lorentz mismatch disease of covariant instantaneity ($CIA$), while the simple trick of `Lorentz completion'ensures a Lorentz invariant structure. The $k^{-4}$ scaling behaviour at large $k^2$ is reproduced. And with the infrared structure of the gluonic propagator attuned to spectroscopy, the charge radius of the proton comes out at $0.96 fm$. The magnetic moments of the baryon octet, also in good accord with data, are expressible as $(a+b\lambda)/(2+\lambda)$, where $a,b$ are purely geometrical numbers and $\lambda$ a dynamics-dependent quantity. PACS: 11.10.St ; 12.90.+b ; 13.40.Fn Key Words : Baryon-$qqq$ Vertex; Markov-Yukawa Principle (MYTP); 3D-4D Interlinkage; Covariant null-plane (CNPA); e.m.form factor;baryon magneton

A STUDY OF TRAVELLING SALESMAN PROBLEM USING REINFORCEMENT LEARNING OVER GENETIC ALGORITHM

This paper represents the applications of Genetic Algorithm (GA) to solve a Travelling Salesmanproblem (TSP). TSP is a simple to describe and mathematically well characterized problem but it is quite difficult to solve. This is a NP-hard type problem i.e. this problem is hard as the hardest problem in NPcomplete space. We present the Crossover and Mutation operators, sorting of the solutions to calculate the bestoptimal solutions. Previously, a numerical illustration was used to signify the model with the techniques. This paper employs Reinforcement Learning to solve the Traveling Salesman problem in the mean of Genetic Algorithm. The technique proposes a model (actions, states, reinforcements)

Privatization, underpricing and welfare in the presence of foreign competition

We analyze privatization in a differentiated oligopoly setting with a domestic public firm and foreign profit-maximizing firms. In particular, we examine pricing below marginal cost by public firm, the optimal degree of privatization and, the relationship between privatization and foreign ownership restrictions. When market structure is exogenous, partial privatization of the public firm improves welfare by reducing public sector losses. Surprisingly, even at the optimal level of privatization, the public firm's price lies strictly below marginal cost, resulting in losses. Our analysis also reveals a potential conflict between privatization and investment liberalization (i.e., relaxing restrictions on foreign ownership) in the short run. With endogenous market structure (i.e., free entry of foreign firms), partial privatization improves welfare through an additional channel: more foreign varieties. Furthermore, at the optimal level of privatization, the public firm's price lies strictly above marginal cost and it earns positive profits