Problems with interpretation of 10^{10}He ground state

The continuum of $^{10}$He nucleus is studied theoretically in a three-body $^{8}$He+$n$+$n$ model basing on the recent information concerning $^9$He spectrum [Golovkov, \textit{et al.}, Phys. Rev. C \textbf{76}, 021605(R) (2007)]. The $^{10}$He ground state (g.s.) candidate with structure $[p_{1/2}]^2$ for new g.s. energy of $^9$He is predicted to be at about $2.0-2.3$ MeV. The peak in the cross section associated with this state may be shifted to a lower energy (e.g. $\sim 1.2$ MeV) when $^{10}$He is populated in reactions with $^{11}$Li due to peculiar reaction mechanism. Formation of the low-energy ($E< 250$ keV) ``alternative'' ground state with structure $[s_{1/2}]^2$ is highly probable in $^{10}$He in the case of considerable attraction (e.g. $a<-5$ fm) in the s-wave $^9$He channel, which properties are still quite uncertain. This result either questions the existing experimental low-energy spectrum of $^{10}$He or place a limit on the scattering length in $^9$He channel, which contradicts existing data.Comment: 14 pages, 13 figures, 1 tabl

Static deflection control of flexible beams by piezo-electric actuators

This study deals with the utilization of piezo-electric actuators in controlling the static deformation of flexible beams. An optimum design procedure is presented to enable the selection of the optimal location, thickness and excitation voltage of the piezo-electric actuators in a way that would minimize the deflection of the beam to which these actuators are bonded. Numerical examples are presented to illustrate the application of the developed optimization procedure in minimizing the structural deformation of beams of different materials when subjected to different loading and end conditions using ceramic or polymeric piezo-electric actuators. The results obtained emphasize the importance of the devised rational procedure in designing beam-actuator systems with minimal elastic distortions

Hartman effect and spin precession in graphene

Spin precession has been used to measure the transmission time \tau over a distance L in a graphene sheet. Since conduction electrons in graphene have an energy-independent velocity v, one would expect \tau > L/v. Here we calculate that \tau < L/v at the Dirac point (= charge neutrality point) in a clean graphene sheet, and we interpret this result as a manifestation of the Hartman effect (apparent superluminality) known from optics.Comment: 6 pages, 4 figures; v2: added a section on the case of perpendicularly aligned magnetizations; v3: added a figur

Superconducting Coherent States for an Extended Hubbard Model

An extended Hubbard model with phonons is considered. q-coherent states relative to the superconducting quantum symmetry of the model are constructed and their properties studied. It is shown that they can have energy expectation lower than eigenstates constructed via conventional processes and that they exhibit ODLRO.Comment: 7 pages, 3 figure

Supervision in the extension service in Helmand Arghandab Valley Authority, Afganistan

"A special problem #400 presented to the Department of Extension Education, University of Missouri, Columbia, in partial fulfillment of the requirements for the degree, Master of Science in Extension Education."Supervision is a process by which subordinates are assisted to perform their activities with increasing satisfaction to themselves, to people with whom they work and to the organization. The principal aim of Extension supervision is maximum growth and development of people. Yet, our recent supervisory practices are incongruent with this philosophy. Supervision is considered synonymous to administration and the supervisor major purpose is to make sure that subordinates do not deviate from the administrative rules and regulations. The chief duty of supervisor is inspection of the execution of plans, policies and procedures that are formulated at the higher level of administrative hierarchy. Extension activities are carried out through the H.A.V.A. Agricultural Division. The top administrative authorities who formulate the Extension programs are highly qualified experts; however, they should pay little attention to the significance of human relations. Supervision by most of them therefore, is conceived as a process of commanding subordinates to follow orders and to act according to direction given to them. The writer has a strong belief in the philosophy of democratic supervision. Democracy anywhere is participatory group life enjoyed by free individuals having the greatest opportunities for participation. Plans, policies, methods, techniques, and procedures of implementation are determined by the group. In here, central determination and direction techniques are replaced by a cooperative and coordinated group efforts. People are invited to take part in the development of plans and decisions which are likely to affect their lives. In the light of this philosophy, supervision must be based upon sound principles of human relations. Supervisor must possess a sound knowledge of the principles of supervision and continuous training in their application to his situation. With concept as such, this paper is condensed from reading of volumes of books and literature which are related to the subject. I hope this will be a valuable guide, not only to myself but to all of those who serve as supervisor in the Extension Service of Afghanistan.Introduction -- A look into the past history of extension service in Helmand-Arghandab Valley, Afghanistan -- The significance of extension supervision -- The supervisor as a leader -- Principles of supervision -- Characteristics of effective supervision -- Qualities necessary to the success of supervisors -- Characteristics and traits of extension supervisors -- Functions of the extension supervisor -- Evaluating the supervisor's performance -- Conclusion and recommendation for the extension service in Helmand-Arghandab Valley, Afghanistan.Includes bibliographical references (pages 78-82

Coherent state quantization of paragrassmann algebras

By using a coherent state quantization of paragrassmann variables, operators are constructed in finite Hilbert spaces. We thus obtain in a straightforward way a matrix representation of the paragrassmann algebra. This algebra of finite matrices realizes a deformed Weyl-Heisenberg algebra. The study of mean values in coherent states of some of these operators lead to interesting conclusions.Comment: We provide an erratum where we improve upon our previous definition of odd paragrassmann algebra

The JJ-matrix inverse scattering approach for coupled channels with different thresholds

The inverse scattering method within the $J$-matrix approach to the two coupled-channel problem is discussed. We propose a generalization of the procedure to the case with different thresholds.Comment: 20 pages, 3 figure

Threshold Effects in Multi-channel Coupling and Spectroscopic Factors in Exotic Nuclei

In the threshold region, the cross section and the associated overlap integral obey the Wigner threshold law that results in the Wigner-cusp phenomenon. Due to flux conservation, a cusp anomaly in one channel manifests itself in other open channels, even if their respective thresholds appear at a different energy. The shape of a threshold cusp depends on the orbital angular momentum of a scattered particle; hence, studies of Wigner anomalies in weakly bound nuclei with several low-lying thresholds can provide valuable spectroscopic information. In this work, we investigate the threshold behavior of spectroscopic factors in neutron-rich drip-line nuclei using the Gamow Shell Model, which takes into account many-body correlations and the continuum effects. The presence of threshold anomalies is demonstrated and the implications for spectroscopic factors are discussed.Comment: Accepted in Physical Review C Figure correcte