Effects of antimitotic agents on haploid plant production from unpollinated ovules of sugar beet (beta vulgaris l.)

The effects of antimicrotubule agents on haploid embryo formation from unpollinated ovules of sugar beet (Beta vulgaris L.) were investigated. The antimitotic agent colchicine (at 100 and 150 mg/l) and trifluralin (at 5.0 mg/l) increased the frequency of haploid embryo formation whereas pronamide (at 76.9 and 128.2 mg/l) and trifluralin (at 3.4 mg/l) decreased. Ovules that were non-treated with antimicrotuble agents (i.e., ovules of the control treatment) produced higher percentages of haploid embryos (4.25 %) when compared to the pronamide and trifluralin at 3.4 mg/l concentration. Toxic effects of these agents on embryo formation from ovules were evident. A significant genotypic variation among the lines used was observed. The line M4 produced the highest yield with a mean of 14.71% haploid embryo production while the line M2 producing no embryos at all

Boundary Value Problems For Integrable Equations Compatible With The Symmetry Algebra

Boundary value problems for integrable nonlinear partial differential equations are considered from the symmetry point of view. Families of boundary conditions compatible with the Harry-Dym, KdV and MKdV equations and the Volterra chain are discussed. We also discuss the uniqueness of some of these boundary conditions.Comment: 25 pages , Latex , no figure

Proudly moving forward and feeling connected: Adolescents’ daily temporal comparisons relate to a desire for growth and sense of relatedness

Adolescents often compare themselves favorably to others. Although such downward social comparisons make adolescents feel proud, they entail the risk of focusing adolescents on outperforming others rather than on improving themselves. This daily diary study (N = 389 adolescents, ages 11–15) tested the hypothesis that downward temporal comparisons—comparing one’s present self favorably to one’s past self, rather than to others—may elicit pride while encouraging adolescents to strive for self-improvement rather than superiority. Such a desire for self-improvement may, in turn, cultivate a sense of relatedness. Results show that daily downward and upward comparisons co-occurred with pride and shame, respectively, regardless of whether those comparisons were social or temporal. Importantly, daily downward temporal comparisons (unlike daily downward social comparisons) co-occurred with a desire for self-improvement over superiority as well as with a sense of relatedness. This desire for self-improvement over superiority partially mediated the association between downward temporal comparison and a sense of relatedness. Together, these findings underline the role of social and temporal comparisons in self-conscious emotions and goal pursuit and suggest that temporal comparisons—unlike social comparisons—may help adolescents strive for personal growth and build satisfying relationships

An anticipative scheduling approach with controllable processing times

In practice, machine schedules are usually subject to disruptions which have to be repaired by reactive scheduling decisions. The most popular predictive approach in project management and machine scheduling literature is to leave idle times (time buffers) in schedules in coping with disruptions, i.e. the resources will be under-utilized. Therefore, preparing initial schedules by considering possible disruption times along with rescheduling objectives is critical for the performance of rescheduling decisions. In this paper, we show that if the processing times are controllable then an anticipative approach can be used to form an initial schedule so that the limited capacity of the production resources are utilized more effectively. To illustrate the anticipative scheduling idea, we consider a non-identical parallel machining environment, where processing times can be controlled at a certain compression cost. When there is a disruption during the execution of the initial schedule, a match-up time strategy is utilized such that a repaired schedule has to catch-up initial schedule at some point in future. This requires changing machine–job assignments and processing times for the rest of the schedule which implies increased manufacturing costs. We show that making anticipative job sequencing decisions, based on failure and repair time distributions and flexibility of jobs, one can repair schedules by incurring less manufacturing cost. Our computational results show that the match-up time strategy is very sensitive to initial schedule and the proposed anticipative scheduling algorithm can be very helpful to reduce rescheduling costs

A conceptual model for public relations in museums

Purpose: This paper aims to present a conceptual model for public relations specific to museums. Design/methodology/approach: Based on relevant literature, a contingency model is developed for the public relations practices of museums. Findings: The model offers the market orientation level of the management and the interest level of the publics as the major factors that influence the effectiveness of the public relations programs in museums. The interest level of the publics is offered as a moderating variable. Practical implications: The model suggests that the effectiveness of the public relations programs of museums depends on two major factors. Although the interest level of the publics may seem to be uncontrollable at first glance, its negative impact can be largely controllable by managers by changing their own market orientation level - by adapting the public relations strategy to the targeted public depending on the interest level of that public. Originality/value: The model is specifically designed for museums. It can be accepted as the first public relations model specifically offered for museums. The model here recognises the relationship between marketing and public relations. © Emerald Group Publishing Limited

Integrable boundary conditions for the Toda lattice

The problem of construction of the boundary conditions for the Toda lattice compatible with its higher symmetries is considered. It is demonstrated that this problem is reduced to finding of the differential constraints consistent with the ZS-AKNS hierarchy. A method of their construction is offered based on the B\"acklund transformations. It is shown that the generalized Toda lattices corresponding to the non-exceptional Lie algebras of finite growth can be obtained by imposing one of the four simplest integrable boundary conditions on the both ends of the lattice. This fact allows, in particular, to solve the problem of reduction of the series $A$ Toda lattices into the series $D$ ones. Deformations of the found boundary conditions are presented which leads to the Painlev\'e type equations. Key words: Toda lattice, boundary conditions, integrability, B\"acklund transformation, Lie algebras, Painlev\'e equation

Tunable dynamics of a flake on graphene: Libration frequency

In this paper we investigated the interaction between a graphene nanoflake anchored to the 2D graphene monolayer. This interaction is attractive but weak and is capable of setting a well defined registry in equilibrium. Rotational and linear displacements from equilibrium registry generate restoring forces, which can be controlled by external agents. Similar flakes can be self-assembled and can also execute simple harmonic motion as if a physical pendulum. Oscillation of a nanoflake about their equilibrium registries resulting in a characteristic libration frequency is predicted. This frequency depends on the size and geometry of the flake. Moreover, the libration frequency, as well as the electronic and magnetic properties of the flake+monolayer systems, can be tuned by a foreign molecule anchored to the flake, by electric charging and applied parallel and perpendicular electric and magnetic fields. When the sliding of the flake is combined with rotation, the friction force can be reduced dramatically. It is surprising that weak interaction can offer such features at nanoscale, which may offer potential applications. Our predictions are obtained by first-principles calculations based on density functional theory. © 2017 American Physical Society