A simplified method for application of natural regeneration in black locust (Robinia pseudoacacia L.) stands in Hungary

Black locust (Robinia pseudoacacia L.) is one of the most important forest tree species in Hungary, covering approximately 24% of the forest land and providing 25% of the annual timber supply. One third of these black locust stands are high forests (planted with seedlings) and the remaining stands are coppices. An auxiliary table was developed for planning the black locust natural regeneration in order to determine the sprouting criteria based on stand volume at the final cutting age. Twenty forest subcompartments were selected for investigating the possibility of black locust regeneration by root suckers. The basic yield and stand structure factors were determined using the numerical yield table for black locust stands. The results show that the regeneration of black locust stands from root suckers can be recommended on good and medium quality sites without a decrease in yield or stem quality. Black locust stands of good and medium quality (yield classes I, II, III and IV) may be regenerated from suckers in general until their growing stock attains and if their health is adequate. The simplicity of the practice-oriented auxiliary table based on the black locust yield table may further the development of management and wood utilization of the species.

Mechanical analysis of an auxiliary table with composite structure

This paper gives a brief summary on the application on of finite element methods during the design of a component. The solutions of mechanical and thermal problems are demonstrated on the given component. Among the several numerical methods the paper focuses on the FEM. During the article we present the problems, then define mechanical simulations for the possible solution that was designed and the evaluation of the results.

Staphylococcus Aureus Contamination in a Pediatric Dental Clinic

Staphylococcus aureus strains can be disseminated during dental treatment and occasionally lead to contamination and infection of patients and dentists. The objective of this study was to determine the frequency and compare the number of S.aureus colonies isolated from the nose, hands and tongue of students and patients, as well as from the clinical environment, before and after dental treatment. Staphylococcus species were isolated from the tongue, nose and hands of 30 students and 30 patients and from the environment of a Pediatric Dentistry Clinic. The samples were incubated in SMA plates at 37o C for 48 hours. Results: The colonies that showed the presence of mannitol fermentation were collected as identification for Staphylococcus aureus, using CHROMagar and the coagulase test. The highest amount of S.aureus was found in the nose and tongue of children. In relation to dental students, more contamination was observed on gloved hands, followed by the tongue and hands without gloves, before clinical attendance. At the end of dental treatment, S. aureus colonies isolated from the gloved hands of students decreased significantly. Considering the clinical environment, the most contaminated areas were the auxiliary table and the storeroom, which was located at the center of the clinic. Conclusion: The dental clinic can be considered an environment for S. aureus cross-transmission. Preventative measures should be used to avoid the dissemination of pathogenic microorganisms.

On Compact Encoding of Pagenumber $k$ Graphs

International audience In this paper we show an information-theoretic lower bound of kn - o(kn) on the minimum number of bits to represent an unlabeled simple connected n-node graph of pagenumber k. This has to be compared with the efficient encoding scheme of Munro and Raman of 2kn + 2m + o(kn+m) bits (m the number of edges), that is 4kn + 2n + o(kn) bits in the worst-case. For m-edge graphs of pagenumber k (with multi-edges and loops), we propose a 2mlog2k + O(m) bits encoding improving the best previous upper bound of Munro and Raman whenever m ≤ 1 / 2kn/log2 k. Actually our scheme applies to k-page embedding containing multi-edge and loops. Moreover, with an auxiliary table of o(m log k) bits, our coding supports (1) the computation of the degree of a node in constant time, (2) adjacency queries with O(logk) queries of type rank, select and match, that is in O(logk *minlogk / loglogm, loglogk) time and (3) the access to δ neighbors in O(δ) runs of select, rank or match;.

Static Characteristic Analysis of a 3-DOF Micropositioning Table for Grinding

In order to improve the machining accuracy of the precision surface grinding machine, a 3-DOF micropositioning table is used as an auxiliary table to form the dual infeed system with nanometer level positioning accuracy. This paper mainly deals with the static characteristics of the micropositioning table. The direct and inverse kinematic models are obtained under different orientation descriptions, and the inherent relationship between different orientation descriptions is investigated. By use of Eular angle description, the reachable orientation space of the micro-positioning table is obtained. The theoretical static stiffness on the top surface of the table is also given, and the experimental tests are carried out to verify the established models.