THE GENERALIZED NEWTON ITERATIVE PROCEDURE

We suggest a class of generalized Newton method in this paper. As special exampls, it contains the usual Chebyshev method, tangent-hypobolic method and steepest descent method.     

读MBA到底有什么用？

一批评者：学会管理要靠实践．而不能靠课程有批评者认为：学会管理要靠实践,而不能靠课堂学习。MBA课程培养出来的是脱离实战的“皇太子”,虽然理论高深,但他们对将要经营的公司却一无所知。社会上真正需要的是靠实践成长起来的企业家,而不是靠书本理论培养出来的专业经理人。那么,MBA专业的目的到底是什么？     

Characterisation of a 16SrII phytoplasma strain associated with bushy stunt of hawkweed oxtongue (Picris hieracioides) in south-eastern Serbia and the role of the leafhopper Neoaliturus fenestratus (Deltocephalinae) as a natural vector

A 2-year study of host association, molecular characterisation and vector transmission of a phytoplasma related to the 16SrII group in a vineyard of south-eastern Serbia was conducted. Grapevine, eight common weeds and 31 Auchenorrhyncha species were collected and analysed for phytoplasma presence. PCR-RFLP analyses of the 16S rRNA gene identified the presence of a new strain of phytoplasma related to the 16SrII group in P. hieracioides with symptoms of stunting or bushy stunting. Grapevine samples, all without symptoms, were negative for phytoplasma presence. Plants of Erigeron annuus, Cynodon dactylon, Daucus carota and P. hieracioides, either exhibiting symptoms of yellowing or without symptoms, were positive for the presence of stolbur phytoplasma. Among the tested cicada species, seven were infected with phytoplasmas from the aster yellows group, two with stolbur phytoplasma, two with 16SrII phytoplasma, and one with the 16SrV-C phytoplasma subgroup. The phytoplasma strain of the 16SrII group was recorded in approximately 50?% of the collected leafhopper species Neoaliturus fenestratus and in a few specimens of the planthopper Dictyophara europaea. The vector status of N. fenestratus was tested using the second generation of the planthopper in two separate transmission trials with P. hieracioides and periwinkle seedlings. In both tests, the leafhopper successfully transmitted 16SrII phytoplasma to exposed plants, proving its role as a natural vector of this phytoplasma in Europe. A finer molecular characterisation and phylogenetic relatedness of the 16SrII phytoplasma strain by sequence analyses of the 16S rRNA and ribosomal protein genes rpl22-rps3 indicated that it was most closely related to the 16SrII-E subgroup.     

The use of statistical methods to evaluate winter oilseed rape doubled haploids for industrial purposes

Doubled haploid (DH) production is valuable technology in modern plant breeding of oilseed rape. Doubled haploids can be produced from in vitro isolated and cultured microspores, which, instead of forming pollen, develop into haploid embryos. Either spontaneously or after artificial doubling of chromosomes, the arising resulting plants are diploid and fertile, and 100% homozygous for all genes. Biotechnological DH production offers various advantages for plant breeders, including the possibility to obtain homozygous lines rapidly, as well as easy selection due to the absence of heterozygosity. A DH line with desirable agronomic characters can be chosen and introduced into a breeding program as a result of selection for a combination of optimum characters. The study presents the application of uni- and multi-variate statistical methods to evaluate winter oilseed rape DH lines studied in a series of six experiments repeated at different localities and over a number of years. These methods made it possible to estimate individual DH lines under various environmental conditions, including the assessment of the content and stability of two different fatty acid compositions. The aim of the study was to classify and select the best oilseed rape genotypes with regard to the requirements of chemical and biodiesel industry concerning fatty acid compositions at simultaneously high seed yield. The paper contains the results of statistical analysis of 37 genotypes (32 DH lines, 2 parental forms, F₂ and F₃ hybrids and standard cultivar) performed on the basis of experiments carried out at 6 environments. A total of 14 genotypes were found satisfactory (11 stable and 3 unstable) for the chemical industry and 10 genotypes satisfactory (6 stable and 4 unstable) for the biodiesel industry. Among them 5 genotypes had very profitable significant and positive estimates of the main effect for seed yield.     

Cadmium and copper reduce hematopoietic potential in common carp (Cyprinus carpio L.) head kidney

The effects of cadmium and copper on activity of common carp head kidney hematopoietic tissue were evaluated. The fish were subjected to short-term (3 h, Cd-s and Cu-s) or long-term (4 weeks, Cd-l and Cu-l) exposures to 100 % 96hLC₅₀ or 10 % 96hLC₅₀, respectively. Head kidneys were isolated weekly from 5 fish of each group for 4 weeks (post-short-term exposure and during long-term exposure). Percentage of early blast cells among the hematopoietic precursors was calculated. Proliferative and apoptotic activity were evaluated using immunocytochemical staining for proliferating cell nuclear antigen (PCNA) and caspase 3, respectively. Hematopoietic activity was calculated as the ratio of proliferating to apoptotic cells. All metal exposures induced an increase in frequency of early blast cells. The frequency of proliferating (PCNA-positive) cells also significantly increased. A considerable and significant increase in the frequency of apoptotic cells was the most pronounced effect of metal exposures. Both short-term and long-term treatments caused similar effects, but in case of Cd exposures, the reaction was more pronounced. All metal exposures reduced hematopoietic potential of fish measured as the ratio of proliferating to apoptotic precursor cell frequency. However, in all cases, hematopoietic activity was higher than 1 showing that the rate of repair of hematopoietic tissue prevailed over destruction.     

Effect of Freezing Technology and Storage Conditions on Folate Content in Selected Vegetables

Folates (B vitamins) are essential for the proper function of many bodily processes. Although a rich natural source are vegetables, the literature lacks data on the effect of the pre-treatment and freezing technologies used in vegetable processing and frozen storage time on the folate content in these materials. Moreover, since folates are very unstable nutrients, the amount available in processed and stored foods can be significantly lower than in raw products. In tested vegetables (green beans, yellow beans, peas, cauliflower, broccoli and spinach), one folate form was identified, 5-methyltetrahydrofolate (5-CH₃-H₄folate). It was observed that pre-treatment and freezing technology significantly (p?<?0.05) decreased 5-CH₃-H₄folate content only in vegetables with the largest degree of fragmentation (cut and briquetted spinach) and the smallest size (peas). In all analyzed samples, the 5-CH₃-H₄folate content decreased with the time of frozen storage. In frozen cauliflower, the 5-CH₃-H₄folate loss exceeded 95 % compared to the fresh product just after the third month of frozen storage. Meanwhile, in green and yellow beans, significant 5-CH₃-H₄folate losses (at the level of 75 % and 95 %, respectively) were observed no earlier than after the 9th month of frozen storage.     

Isolation of Actinobacillus pleuropneumoniae serovar 15-like strain from a field case of porcine pleuropneumonia in Japan

An Actinobacillus pleuropneumoniae strain isolated from a field case of porcine pleuropneumonia in Japan, was closely related to a reference strain of serovar 15, which is a newly proposed serovar according to an analysis of field isolates originating from Australia. The isolate had biological and biochemical properties consistent with A. pleuropneumoniae biovar 1, and reacted strongly to a rabbit antiserum raised against a reference strain of serovar 15 in an agar gel precipitation test. The nucleotide sequence of a hyper variable region in the 16S RNA gene of the isolate was identical to that of the reference strain of serovar 15. The isolate possessed A. pleuropneumoniae-RTX toxin (Apx) II, III, and IV genes, consistent with serovar 15. Its virulence in mice was lower than that of ApxI-bearing strains but higher than that of other ApxIII-bearing strains. This is the first report describing the isolation of A. pleuropneumoniae serovar 15-like strain from a country or region other than Australia.     

Metal-Metal Interactions in Biological Systems. Part V. Steinernema Carpocapsae (Steinernematidae) and Heterorhabditis Bacteriophora (Heterorhabditidae) Entomopathogenic Nematodes

In spite of a lack of acute toxicity of single metal ions, in 96 hour laboratory tests there was a long term toxicity againstS. carpocapsae andH. bacteriophora nematodes. The 96 hour laboratory tests were carried out in order to prove possible synergistic and antagonistic interactions between pairs of metal ions. Thus, the pairs of ions were arranged from each of Al, Cd, Co(II), Cr(III), Cr(VI), Cu(II), Fe(III), Li, Mo(VI), Ni(II), Sc(IV), V(V) and Zn on one side and Mn(II) and Mg on the other. Mn(II) and Mg ions considerably reduced the nematode mortality and increased their infectivity againstGalleria mellonella caterpillars.