Arrangements of minimal variance—Multidimensional scaling in the symmetrical case

AbstractWe deal with the problem of how to arrange n points in the plane with a given mean and minimal variance. Ordinary and multiple multidimensional scaling are outlined, investigated in the symmetrical case and applied to congenital abnormalities

On the Interpretation of the Redshift in a Static Gravitational Field

The classical phenomenon of the redshift of light in a static gravitational potential, usually called the gravitational redshift, is described in the literature essentially in two ways: on the one hand the phenomenon is explained through the behaviour of clocks which run the faster the higher they are located in the potential, whereas the energy and frequency of the propagating photon do not change with height. The light thus appears to be redshifted relative to the frequency of the clock. On the other hand the phenomenon is alternatively discussed (even in some authoritative texts) in terms of an energy loss of a photon as it overcomes the gravitational attraction of the massive body. This second approach operates with notions such as the "gravitational mass" or the "potential energy" of a photon and we assert that it is misleading. We do not claim to present any original ideas or to give a comprehensive review of the subject, our goal being essentially a pedagogical one.Comment: latex, 16 pages, to be published in American Journal of Physic

The Influence of Watershed Development on the Eutrophication of Shallow Lakes: A Modeling Approach Applied to Lake Balaton

A multiregional, multicriteria watershed development model is presented as a way of describing the eutrophication processes in shallow lakes on an annual basis. Its application to Lake Balaton is illustrated. The simulation and forecasting of eutrophication in the lake, which depend on different watershed development activities, is discussed for the period 1981-85. The formulation of the model rests on the fact that a close connection exists between the eutrophication of a shallow lake and the development of its watersheds which generate nutrient loading. A multicriteria utility function is used to describe watershed development. The applications of the model to Lake Balaton are presented; they are based on the regionalization of the Balaton basin into eleven regional units (four waterbodies and seven watersheds). Watershed development needs are assessed for the various watersheds of the Balaton basin, for the period 1930-1980. The eutrophication indicated by a moving summer average of chlorophyll-a for each of the four basins of the lake depends on the level of watershed development in the corresponding or contributing watershed, their geometric character and the eutrophication in the preceding basin. The spatial distribution of the water quality within basins is not considered. The model parameters are elaborated by regression analysis. The simulation of eutrophication is based on three development variations for each watershed for 1981-85, namely a strong, a medium and a zero growth variation. Using different combinations of the specific watershed variations, more than 30 spatial lake protection strategies and their effects on eutrophication were simulated on an annual time scale. The average uncertainty of the simulated eutrophication values for the whole lake is plus/minus 23%. With the help of this simulation, the spatial efficiency of the comprehensive control actions in the watershed has been measured. The forecast of eutrophication by 1985 is given by the most realistic watershed development strategy. One of the more important recommendations is that the most efficient development management, i.e., control strategy from the viewpoint of the whole lake, is the very one which concentrates all of the limited, available control efforts in the next five years on the Zala watershed, which is the largest source of nutrient loading. This suggestion is based on the relative efficiency figures of the protection measures taken for the various watersheds and calculated by the model. To illustrate the use of the model for evaluating the effectiveness of different management actions and lake protection policies, the possible effects of the Kis-Balaton reservoir on eutrophication are identified. The model can be combined with other models dealing with the Lake Balaton problem and applied to the eutrophication problem of other shallow lakes and man-made storage reservoirs

A Watershed Development Approach to the Eutrophication Problem of Lake Balaton (A Multiregional and Multicriteria Model)

The approach to long-term management of the eutrophication of a lake proposed in this paper is based on the hypothesis that a close relation exists between the human activity in the watershed and the degree of eutrophication in the adjacent waterbody. The method builds on the watershed development approach applied earlier to water resources planning. To test the basic hypothesis and to investigate the relationship in quantitative form an application to the eutrophication problem of Lake Balaton has been attempted. For this purpose the Balaton catchment was separated into regional units with differing degrees of development. In view of the main water transport direction in Lake Balaton, the adjacent waterbodies can be considered as a hierarchical system. For this multiregional, hierarchical system a model was formulated in which the effects of the relevant watershed development factors and natural factors on the nutrient loading from the watershed are expressed in one condensed watershed development figure. Comparison of the development figure for various time instants and various regions with historical and spatial data for the degree of eutrophication should then allow the specification of the relation in a numerical form. The actual application presented in this paper is of preliminary nature because data for the existing level of watershed development (1975-76) were available only. A system of 25 nutrient loading effecting watershed development criteria was designed on the basis of 50 development and natural factors selected from available statistical data. The 25 criteria were then composed into a development indicator for the four watershed regions using 7 alternative weighting systems. The results were compared with 3 alternative eutrophication indices derived from phytoplankton biomass data. The model relationship was analyzed by means of correlation analysis, and a tentative assessment was made of the sensitivity to weighting system and eutrophication index. The first numerical results support the idea behind the basic hypothesis of the watershed development approach. The quantitative results agree with subjective opinions on the present situation in the Balaton region. The overall conclusion is that it is worthwhile to pursue the line of research of this report as a perspective tool in the simulation of the effects of long-term watershed development policies on the eutrophication of the lake. The collection of the necessary historical data for this purpose is highly recommended

Contact Angle Measurement is an Efficient Tool for the Characterization of Corrosion Pro-tection Nanolayers on Copper Alloys and Stainless Steel

With the advent of the nano-era, a pronounced interest in the nanolayers has emerged. The develop-ment of more and more sophisticated measurement devices and techniques made possible the visualiza-tion, characterization and investigation of nanolayers. However, there exists a variety of simple, old means which should not be despised either. In this work, the use of contact angle measurement as a simple, fast, inexpensive and accessible tool for the study of surfaces with and without nanolayers is demonstrated. Furthermore, it is evidenced that in contrast to its simplicity, contact angle measurement can address sur-prisingly complex questions and give proper answers to these. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3525

Interview with Valentine L. Telegdi

Valentine Louis Telegdi was born in Budapest in 1922 and grew up in Bulgaria. He took his Master of Science degree in chemical engineering at Lausanne University in 1946 and received his PhD in 1950 from the ETH (Eidgenössische Technische Hochschule), the Swiss Federal Institute of Technology. Victor Weisskopf and Gregor Wentzel were instrumental in his appointment as an instructor at the University of Chicago in 1951, where he worked with Murray Gell-Mann. In 1954, after Enrico Fermi's death, Telegdi became the head of Fermi's Nuclear Emulsion Group there. In 1956, he went to the Institute for Advanced Study for three months. Later that year, back in Chicago, he and Jerome I. Friedman found parity violation in muon decay, in parallel with the work of Chien-Shiung Wu at Columbia and her collaborators at the National Bureau of Standards, and that of Richard L. Garwin, Leon M. Lederman, and Marcel Weinrich at Columbia. In 1959-1960, on leave from Chicago, Telegdi worked with Garwin at CERN on the anomalous magnetic moment of the muon. In 1966, again on leave from Chicago, he had a visiting lectureship at Harvard. In 1968, Telegdi was elected to the National Academy of Sciences and in 1972 he became the Enrico Fermi Distinguished Service Professor of Physics at Chicago. He left the university four years later--discouraged at what he called the "decay" of the Enrico Fermi Institute since Fermi's death and the increasingly cumbersome grants process--and returned to Switzerland, where he headed a group at the ETH doing atomic physics; he also took up a joint appointment at CERN, heading a particle physics group. In 1981, he began coming regularly as a visiting professor to Caltech, where he worked with (among others) Gell-Mann, Richard Feynman, and Felix Boehm. In 1991 he was awarded (along with Maurice Goldhaber) the Wolf Prize for his work on the weak interactions and in 1995 the American Physics Society's Julius Lilienfeld Prize. In 2003, he was elected a foreign member of the Royal Society. He died in Pasadena, California, on April 8, 2006, at the age of eighty-four

Adsorption of a PEO–PPO–PEO triblock copolymer on metal oxide surfaces with a view to reducing protein adsorption and further biofouling

Biomolecule adsorption is the first stage of biofouling. The aim of this work was to reduce the adsorption of proteins on stainless steel (SS) and titanium surfaces by modifying them with a poly(ethylene oxide) (PEO)–poly(propylene oxide) (PPO)–PEO triblock copolymer. Anchoring of the central PPO block of the copolymer is known to be favoured by hydrophobic interaction with the substratum. Therefore, the surfaces of metal oxides were first modified by self-assembly of octadecylphosphonic acid. PEO–PPO–PEO preadsorbed on the hydrophobized surfaces of titanium or SS was shown to prevent the adsorption of bovine serum albumin (BSA), fibrinogen and cytochrome C, as monitored by quartz crystal microbalance (QCM). Moreover, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry were used to characterize the surfaces of the SS and titanium after competitive adsorption of PEO–PPO–PEO and BSA. The results show that the adsorption of BSA is well prevented on hydrophobized surfaces, in contrast to the surfaces of native metal oxides