Showing papers by "Hungarian Academy of Sciences published in 1981"
TL;DR: It is shown that with probability 1-o(1)all eigenvalues belong to the above intervalI if μ=0, while in case μ>0 only the largest eigenvalueλ1 is outsideI, and λ1 asymptotically has a normal distribution with expectation (n−1)μ+v+(σ2/μ) and variance 2σ2 (bounded variance!).
Abstract: LetA=(a ij ) be ann ×n matrix whose entries fori≧j are independent random variables anda ji =a ij . Suppose that everya ij is bounded and for everyi>j we haveEa ij =μ,D 2 a ij =σ2 andEa ii =v.
779 citations
TL;DR: In this article, the chloroplast type (N. tabacum = NT or N. knightiana = NK) in the plants was determined on the basis of the species specific EcoRI restriction pattern of the chloropslast DNA.
Abstract: Protoplasts of Nicotiana tabacum SRI (streptomycin resistant) and of Nicotiana knightiana (streptomycin sensitive) were fused using polyethylene glycol treatment. From three heterokaryons 500 clones were obtained. From the 43 which were further investigated, 6 resistant, 3 sensitive, and 34 chimeric (consisting of resistant and sensitive sectors) calli were found. From eight clones, a total of 39 plants were regenerated and identified as somatic hybrids. Chloroplast type (N. tabacum = NT or N. knightiana = NK) in the plants was determined on the basis of the species specific EcoRI restriction pattern of the chloroplast DNA. Regenerates contained NT (13 plants) or NK (15 plants) plastids but only the plants with the NT chloroplasts were resistant to streptomycin. This finding and our earlier data on uniparental inheritance points to the chloroplasts as the carriers of the streptomycin resistance factor.
364 citations
TL;DR: R meliloti strain 41 (Rm41) was shown to harbor two indigenous plasmids with molecular weights of 140 Mdal (pRmc41a) and more than 300 Mdal(pRme41b), respectively using a heat-treatment procedure, derivatives of Rm41 defective in nodulation (Nod-) or nitrogen fixation (Fix-) have been readily obtained as discussed by the authors.
Abstract: R meliloti strain 41 (Rm41) was shown to harbour two indigenous plasmids with molecular weights of 140 Mdal (pRmc41a) and more than 300 Mdal (pRme41b), respectively Using a heat-treatment procedure, derivatives of Rm41 defective in nodulation (Nod-) or nitrogen fixation (Fix-) have been readily obtained In some Nod- mutants the deletion of a segment of plasmid pRme41b was found
313 citations
TL;DR: I was asked to write a paper about the major unsolved problems in com-binatorial mathematics, but after some thought it seemed better to modify the title to a less pretentious one, so I state only my three favourite problems.
Abstract: I was asked to write a paper about the major unsolved problems in com-binatorial mathematics. After some thought it seemed better to modify the title to a less pretentious one. Combinatorial mathematics has grown enormously and a genuine survey would have to include not only topics where I have no real competence but also topics about which I n e v er seriously thought, e.g. algorithmic combinatorics, coding theory and matroid theory. There is no doubt that the proof of the conjecture that several simply stated problems have no good algorithm is fundamental and may h a ve i m-portant consequences for many other branches of mathematics, but unfortunately I have no real feeling for these questions and I feel I should leave the subject to those who are more competent. I just heard that Khachiyan 59], has a polynomial algorithm for linear programming. (See also 50].) This is considered a sensational result and during my last stay i n the U.S. many o f m y friends were greatly impressed by i t. First of all I will discuss some problems on set systems. I state only my three favourite problems, but before starting I refer to the survey paper 31].
299 citations
TL;DR: In this paper, domestic synthesized HZSM-5 and HSZM-11 zeolites were shown to have the same crystal morphology and unit cell dimensions as the Mobil materials.
268 citations
TL;DR: It is proved that given any family F of subsets of X having maximum degree n [cardinality n], one can find integers αi, i=1,2,… so that f(n) − 1 and g (n)≤c(n log n) 1 2 are proved.
261 citations
TL;DR: A new and simple method is proposed for finding good encoders both for channels and for sources with side information, which relies on the continuous version of a graph decomposition result of Lovasz.
Abstract: A new and simple method is proposed for finding good encoders both for channels and for sources with side information. This method relies on the continuous version of a graph decomposition result of Lovasz. The presently known best exponential error bounds for both problems follow in a unified manner with an improvement on the source coding bound. The previous bounds for universal codes of the authors and Marton are also improved.
231 citations
01 Jan 1981
TL;DR: In this article, the multiple Wiener-ito integrals with respect to a Gaussian random spectral measure were introduced and some important results about them were proved. But these integrals were not considered in this paper.
Abstract: Here we introduce the multiple Wiener–ito integrals with respect to a Gaussian random spectral measure and prove some important results about them.
221 citations
183 citations
TL;DR: This paper proves a corollary to a more general theorem on not necessarily intersecting hypergraphs, and says that ℋ is intersecting if for anyH,H′ ∈ℋ H ∩H′ ≠ 0.
Abstract: Let ℋ be a family ofr-subsets of a finite setX. SetD(ℋ)=\(\mathop {\max }\limits_{x \in X} \)|{E:x∈E∈ℋ}|, (maximum degree). We say that ℋ is intersecting if for anyH,H′ ∈ ℋ we haveH ∩H′ ≠ 0. In this case, obviously,D(ℋ)≧|ℋ|/r. According to a well-known conjectureD(ℋ)≧|ℋ|/(r−1+1/r). We prove a slightly stronger result. Let ℋ be anr-uniform, intersecting hypergraph. Then either it is a projective plane of orderr−1, consequentlyD(ℋ)=|ℋ|/(r−1+1/r), orD(ℋ)≧|ℋ|/(r−1). This is a corollary to a more general theorem on not necessarily intersecting hypergraphs.
157 citations
TL;DR: This work uses a random construction for giving a sequence that is slightly denser than the above trivial one, and remark that using random construction Erdos and Renyi proved the existence of an infinite sequence S with fs(n) > cn l-e (for all n) such that the number of solutions of the equation is zero.
TL;DR: Irradiation significantly increased the frequency of segregant formation with the non-irradiated N. plumbaginifolia nuclei and had an improved chance of dominating the heterokaryonderived cells, many of which contained N. tabacum chloroplasts, so the system described should be generally applicable for the transfer ofchloroplasts without the use of selectable genetic markers.
Abstract: Protoplasts of a light sensitive plastome mutant of Nicotiana tabacum (2 n=48) were irradiated and fused with iodoacetate-treated Nicotiana plumbaginifolia (2 n=20) protoplasts. Treated parental protoplasts were unable to divide. Metabolic complementation, however, helped the recovery of interspecific fusion products which survived and formed calli. Altogether 40 clones were investigated. N. plumbaginifolia plants were obtained in 15 clones (38%), somatic hybrids in 23 clones, and both types of regenerates were found in 2 clones. Irradiation therefore significantly increased the frequency of segregant formation with the non-irradiated N. plumbaginifolia nuclei (the frequency was 1.4% in the absence of irradiation). Regenerated plants in most cases (31 out of 34) contained chloroplasts from the irradiated parent. In 6 clones plants were obtained with both types of chloroplast. Thus, irradiated N. tabacum chloroplasts had an improved chance of dominating the heterokaryonderived cells, many of which contained N. plumbaginifolia nucleus. The system described should be generally applicable for the transfer of chloroplasts without the use of selectable genetic markers.
TL;DR: A random graph with (1+ε)n/2 edges contains a path of lengthcn.
Abstract: A random graph with (1+e)n/2 edges contains a path of lengthcn. A random directed graph with (1+e)n edges contains a directed path of lengthcn. This settles a conjecture of Erdos.
TL;DR: The DNA sequence of a complete hsp70 † gene of the 87A7 type and of the adjacent regions from both variants, extending to 1·2 × 10 3 bases upstream from the start of the messenger coding region, is presented.
TL;DR: The control of frost resistance in the set of chromosome substitution lines of the variety ‘Cheyenne’ into ‘Chinese Spring’ indicated that the genes responsible for the frost resistance of ‘ Cheyenne' are localised in chromosomes 5A, 7A, 4B, 5B, 4D and 5D.
Abstract: Genetic studies of frost resistance were performed on various wheat varieties using diallel, F2 monosomic and substitution analysis. A six-parental cross including reciprocals was carried out, and F1 hybrids and their parents were used for the freezing tests under controlled conditions. Both the general combining ability (GCA) and the specific combining ability (SCA) were significant, indicating additive and non-additive gene action in the inheritance of frost resistance. The high GCA∶SCA ratio revealed a preponderance of additive genetic variance. No significant reciprocal differences were found between the reciprocal crosses. The variance/covariance graphical analysis indicated the partial dominance of frost sensitivity. Frost sensitive varieties had the largest number of dominant genes, while frost resistant varieties had the highest proportion of recessive genes. The magnitude of the additive component of variation was higher than that of the dominance component, and the overall measure of the degree of dominance was smaller than one, so average dominance is incomplete. The increasing and decreasing alleles are not equally frequent at all loci. In this set of wheat varieties the values of narrow and broad heritability are relatively high. F2 monosomic analysis of the winter wheat variety ‘Arthur’ crossed with the monosomics of ‘Chinese Spring’ revealed that the average frost resistance of all the 21 monosomics was lower than that of the disomic. F2 monosomic hybrids 5A, 2B, 4B and 5D proved to be relatively frost resistant, while monosomics 3A, 3B and 6D were the most sensitive. The control of frost resistance in the set of chromosome substitution lines of the variety ‘Cheyenne’ into ‘Chinese Spring’ (with the exception of 2B) indicated that the genes responsible for the frost resistance of ‘Cheyenne’ are localised in chromosomes 5A, 7A, 4B, 5B, 4D and 5D. The genetic basis of frost resistance and problems of analysis are discussed.
TL;DR: The high free energies of activation and long half-lives of the thermoluminescence bands suggest that thermolUMinescence in the temperature region from -80 degrees C to 80+ C does not reflect the change recombination of primary products but represent the reversal of subsequent stabilization steps of the charge separation process which proceed along the acceptor and donor sides of Photosystem II.
TL;DR: In this article, the authors investigated the possibility of collision-induced transitions of a vacancy between the L subshells of atoms, when the vacancy is created by direct ionisation at heavy-ion impact.
Abstract: The authors investigate the possibility of collision-induced transitions of a vacancy between the L subshells of atoms, when the vacancy is created by direct ionisation at heavy-ion impact. A simple model with a two-step mechanism for the production and rearrangement of a vacancy is presented. The success of this model indicates that intra-shell excitations (de-excitations) during the collision are probably responsible for the previously observed large discrepancies between the theory and experiment in the L-shell ionisation of gold by carbon, nitrogen and oxygen ions.
TL;DR: In this paper, it was shown that the product limit estimator of F is almost sure consistent with rate O(√log log n/n), that is P(sup ¦F====== *� �� ��(u)− F(u)-¦=0(1 −∞0, where T====== F>>\s �� =sup{x∶ F(x)>0}.
Abstract: Let X
1,X
2,...,X
n
be i.i.d. r.v.'-s with P(X>u)=F(u) and Y
1,Y
2,...,Y
n
be i.i.d. P(Y>u)=G(u) where both F and G are unknown continuous survival functions. For i=1,2,...,n set δ
i=1 if X
i
≦Y
i
and 0 if X
i
>y
i
, and Z
i
=min {itXi, Yi}. One way to estimate F from the observations (Z
i
,δ
i
) i=l,...,n is by means of the product limit (P.L.) estimator F
*
(Kaplan-Meier, 1958 [6]). In this paper it is shown that F
n
*
is uniformly almost sure consistent with rate O(√log logn/√n), that is P(sup ¦F
*
(u)− F(u)¦=0(√log log n/n)=1 −∞0, where T
F
=sup{x∶ F(x)>0}. A similar result is proved for the Bayesian estimator [9] of F. Moreover a sharpening of the exponential bound of [3] is given.
TL;DR: In this article, the ring transformation occuring in aqueous media of the dihydro intermediates and their salts, respectively appearing during the synthesis of 2-substitutedamino-as-triazino[6,5-c]quinolines, are reported.
TL;DR: Electron microscopic analysis of serial sections revealed that both superficial tufted cells and small periglomerular neurons were labelled, giving further support for the view that dopamine neurons in the rat olfactory bulb do not represent a homogeneous cell population.
Abstract: Several neurons around the glomeruli in the rat olfactory bulb contain the enzyme tyrosine hydroxylase as revealed by light and electron microscopic immunohistochemistry. Electron microscopic analysis of serial sections revealed that both superficial tufted cells and small periglomerular neurons were labelled. These results give further support for the view that dopamine neurons in the rat olfactory bulb, from a neuroanatomical point of view, do not represent a homogeneous cell population. Furthermore, taken together with previous results in the literature our findings indicate that, from a transmitter histochemical point of view, neither tufted cells nor periglomerular neurons represent a homogeneous cell population.
TL;DR: In this paper, the elastic peak is composed of electrons escaping from a surface layer determined by the inelastic mean free path of primary electrons, and the backscattering cross-sections are determined.
Abstract: Elastic peak electron spectroscopy deals with the spectra of secondary electrons in the neighbourhood of Ep primary energy and determines them in absolute units based on the Ne percentage of elastically reflected electrons. A procedure is described for evaluating elastic peak spectra. Experimental results on graphite, Si, Ge, stainless steel, Mo, W and Au polycrystalline samples are presented in the medium energy (Ep = 1–3 ke V) range. Spectra were measured with a cylindrical mirror analyser operated in the direct current mode. For elements (Si, Mo, etc.) Ne is determined mainly by the atomic number Z, Ne(Z)∼(Z – 26)0.65 was found for Z ≥ 26 and Ep = 3.1 ke V. The Ep dependence of Ne can be approximated by a power law Ne(Ep)∼Ep−β(Z), with β(Z) varying between 2 and 0.4 for the Z = 4–79 atomic number range. The elastic peak is composed of electrons escaping from a surface layer determined by the inelastic mean free path of primary electrons. Using Seah's values and from the Ne experimental data the backscattering cross-sections were determined. They varied between 5 × 10−20(C)−2.8 × 10−18 cm2 (W, Au). Some new results are presented on the volume plasmon losses. In Si and Ge the mean free path of medium energy electrons is determined by the first volume plasmon loss, whereas in metals the contributions of other loss processes are important. It is practical to use the elastic peak and Ne as references for Auger and loss peaks allowing the estimation of ionization cross-sections in Auger electron spectroscopy.
TL;DR: It is proved that R(N)=N1/4+o(1) thus showing that Roth’s original lower bound was essentially best possible, and the notion ofdiscrepancy of hypergraphs is introduced and derive an upper bound from which the above result follows.
Abstract: Letg be a coloring of the set {1, ...,N} = [1,N] in red and blue. For each arithmetic progressionA in [1,N], consider the absolute value of the difference of the numbers of red and of blue members ofA. LetR(g) be the maximum of this number over all arithmetic progression (thediscrepancy ofg). Set
$$R(N) = \mathop {\min }\limits_g R(g)$$
over all two-coloringsg. A remarkable result of K. F. Roth gives*R(N)≫N
1/4. On the other hand, Roth observed thatR(N)≪N
1/3+ɛ and suggested that this bound was nearly sharp. A. Sarkozy disproved this by provingR(N)≪N
1/3+ɛ. We prove thatR(N)=N
1/4+o(1) thus showing that Roth’s original lower bound was essentially best possible. Our result is more general. We introduce the notion ofdiscrepancy of hypergraphs and derive an upper bound from which the above result follows.
TL;DR: Mitochondrial DNA was studied in the leaves of Nicotiana tabacum+Nicotiana knightiana somatic hybrids, finding novel patterns can be explained by new combinations of unaltered parental mtDNA molecules, and by genetic recombination.
Abstract: Mitochondrial DNA (mtDNA) was studied in the leaves of Nicotiana tabacum+Nicotiana knightiana somatic hybrids previously described. Restriction patterns generated by the SalI and BamHI restriction endonucleases were different from both parents in the eight hybrids, and made up of parental and non-parental fragments. Rearrangements in the mtDNAs have been confirmed by DNA-DNA hybridization using, as a probe, labelled 2/12 plasmid DNA which contains the E. coli 16S and 23S rRNA genes. Novel patterns can be explained by new combinations of unaltered parental mtDNA molecules, and by genetic recombination.
TL;DR: The last larval moult of Galleria mellonella is induced by an elevation of ecdysteroid titre to more than 200 ng/g, which indicates that the function of prothoracic glands in intact larvae is restrained, probably by the juvenile hormone (JH).
TL;DR: In this article, the uniform interpretation of gas/solid physical adsorption means that the different types of isotherms can be described by means of a single isotherm equation derived from the dynamical character of adorption.
TL;DR: The isolation of an isoleucine-requiring line from haploid cell cultures of Nicotiana plumbaginifolia and the regeneration of diploid plants with no detectable activity of L-threonine deaminase (EC 4.2.1.16), the first enzyme in isoleUCine biosynthesis.
Abstract: Well characterized auxotrophic mutants would greatly assist the genetic manipulation of flowering plants, but such mutants are rare1–3. Moreover, auxotrophic mutants isolated at the plant level4–8 and some of those isolated in cell cultures9 are leaky. The isolation of the first non-leaky auxotrophic mutant, requiring a source of nitrogen in reduced form, was possible by direct selection for chlorate resistance of this rare mutant type10. A different approach, the individual testing of colonies grown from mutagenized haploid cells of Datura11 and Hyoscyam us12, has resulted in cell lines with absolute nutritional requirement. We report here the isolation of an isoleucine-requiring line from haploid cell cultures of Nicotiana plumbaginifolia and the regeneration of diploid plants. These plants have no detectable activity of L-threonine deaminase (EC 4.2.1.16), the first enzyme in isoleucine biosynthesis.
TL;DR: This method gives direct information about the dendritic arborization of a neuron, and its putative transmitter, and allows the identification of its synaptic connections.
TL;DR: It is proved that almost all graphs are counter-examles in a very strong sense.
Abstract: Hajos conjectured that everys-chromatic graph contains a subdivision ofKs, the complete graph ons vertices. Catlin disproved this conjecture. We prove that almost all graphs are counter-examles in a very strong sense.
TL;DR: The described isolation and purification method yielded relatively pure chromosome suspension and the uptake of the isolated plant chromosomes into recipient wheat, parsley, and maize protoplasts was induced by polyethylene-glycol treatment.
Abstract: For mass isolation of plant metaphase chromosomes, cultured cells of wheat (Triticum monococcum) and parsley (Petroselinum hortense) were synchronized by hydroxyurea and colchicine treatment. This synchronization procedure resulted in high mitotic synchrony, especially in suspension cultures of parsley in which 80% of the cells were found to be at the metaphase stage. Mitotic protoplasts isolated from these synchronized cell cultures served as a source for isolation of chromosomes. The described isolation and purification method yielded relatively pure chromosome suspension. The uptake of the isolated plant chromosomes into recipient wheat, parsley, and maize protoplasts was induced by polyethylene-glycol treatment. Cytological studies provided evidences for uptake of plant chromosomes into plant protoplasts.
TL;DR: The world's largest industrial process, ammonia synthesis, uses promoted iron catalysts as mentioned in this paper, and the importance of this latter process has increased during the last few years because of the current energy crisis.
Abstract: The world's largest industrial process, ammonia synthesis, uses promoted iron catalysts. Fifty years ago fused and promoted iron catalysts were first utilized in the Fischer-Tropsch synthesis. The importance of this latter process has increased during the last few years because of the current energy crisis. Iron sulfide catalysts were also used by Varga [1] for the high pressure hydrogenation of coal. This procese, however, has been substituted by other methods.