Small-Scale Horizontal Variations in Ionic Concentrations of Bulk Deposition from Hong Kong     

Tanner  Peter A.  Fai  Tam Wing 《Water, air, and soil pollution》2000,122(3-4):433-448

The concentrations of major anions andcations in bulk deposition were found to varyspatially by factors of up to 65, for two samplings at17 sampling sites separated by 45 km or less in theTerritory of Hong Kong. Under predominantly maritimeairstreams, these variations resulted from localemissions, as well as from lower seasaltconcentrations at the more northerly sites. The weakacidity of the bulk deposition resulted fromneutralization of hydrometeors by basic particulatematter, leading to an unusual anticorrelation of theconcentrations of non-seasalt sulphate and hydrogenions. Greater anthropogenic activity at inland andindustrial sites was generally marked by highernitrate concentrations, with the ratio of nitrate ionconcentrations from the two samplings being stronglycorrelated with that of calcium ion. Chloride lossincreased with increasing concentrations ofnon-seasalt nitrate and sulphate. Most of the variancein the bulk deposition data for 8 major anions andcations could be explained by 2 factors: seasalt andanthropogenic, in common with the 1997 EnvironmentalProtection Department data for these species in totalsuspended particulate matter. Results for 14 solubletrace metal species in the bulk deposition at thesites are also reported.  相似文献   

The more we do,the less we gain? Balancing effort and efficacy in managing the Solidago gigantea invasion     

Dávid U. Nagy  Emily S. J. Rauschert  Tamás Henn  Kevin Cianfaglione  Szilvia Stranczinger  Robert W. Pal 《Weed Research》2020,60(3):232-240

Developing invasive plant management strategies is an important task in modern ecology, conservation biology and land management. Solidago gigantea is considered a problematic invader in Europe and Asia, where it forms dominant stands that can decrease species diversity. There is, therefore, an urgent need for effective management to reduce S. gigantea infestations and their negative impacts. We examined the efficacy of multiple approaches to S. gigantea management in Hungary. In our study, we evaluated the effect of several long-term management techniques such as grazing, mowing and periodic flooding on the invader's density as well as native community diversity. In addition, we investigated the short- and long-term effects of mowing combined with other treatment options, to estimate the influence of increased management intensity. Our results indicate that all tested management techniques had negative impacts on S. gigantea density. Short-term mowing did not appear to improve species diversity in the resident community; however, all long-term options improved species diversity. Moreover, combining treatments with mowing varied in its effectiveness; mowing once increased the efficacy of flooding, but decreased the efficacy of grazing, while mowing twice decreased efficacy of flooding. We suspect this is due to the increased intensity of disturbance, which does not allow for the natural recovery of communities, and after management ceases, invasion is able to re-occur. Our results indicate that for effective management, we need to combine management options which act via different mechanisms, leading to cumulative positive effects on the resident community when applied at moderate levels.  相似文献   

Excitatory effect of GABAergic axo-axonic cells in cortical microcircuits     

Szabadics J  Varga C  Molnár G  Oláh S  Barzó P  Tamás G 《Science (New York, N.Y.)》2006,311(5758):233-235

Axons in the cerebral cortex receive synaptic input at the axon initial segment almost exclusively from gamma-aminobutyric acid-releasing (GABAergic) axo-axonic cells (AACs). The axon has the lowest threshold for action potential generation in neurons; thus, AACs are considered to be strategically placed inhibitory neurons controlling neuronal output. However, we found that AACs can depolarize pyramidal cells and can initiate stereotyped series of synaptic events in rat and human cortical networks because of a depolarized reversal potential for axonal relative to perisomatic GABAergic inputs. Excitation and signal propagation initiated by AACs is supported by the absence of the potassium chloride cotransporter 2 in the axon.  相似文献   

Chloroplast diversity indicates two independent maternal lineages in cultivated grapevine (Vitis vinifera L. subsp. vinifera)     

Rita Lózsa  Ning Xia  Tamás Deák  György Dénes Bisztray 《Genetic Resources and Crop Evolution》2015,62(3):419-429

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Optimization of cryoprotectant treatment for the vitrification of immature cumulus-enclosed porcine oocytes: comparison of sugars,combinations of permeating cryoprotectants and equilibration regimens     

Tamás SOMFAI  Nguyen Thi MEN  Junko NOGUCHI  Hiroyuki KANEKO  Naomi KASHIWAZAKI  Kazuhiro KIKUCHI 《The Journal of reproduction and development》2015,61(6):571-579

Our aim was to optimize the cryoprotectant treatment for the preservation of immature porcine cumulus-oocyte complexes (COCs) by solid surface vitrification. In each experiment, the vitrification solution consisted of 50 mg/ml polyvinyl pyrrolidone, 0.3 M of the actual sugar and in total 35% (v/v) of the actual permeating cryoprotectant (pCPA) combination. After warming, the COCs were subjected to in vitro maturation, fertilization and embryo culture. In Experiment 1, trehalose and sucrose were equally effective during vitrification and warming in terms of facilitating oocyte survival and subsequent embryo development. In Experiment 2, when equilibration was performed at 38.5 C in a total of 4% (v/v) pCPA for 15 min, the combination of ethylene glycol and propylene glycol (EG + PG = 1:1) was superior to EG and dimethyl sulfoxide (EG + DMSO = 1:1) in terms of oocyte survival after vitrification and the quality of resultant blastocysts. In Experiment 3, equilibration in 4% (v/v) pCPA for 15 min before vitrification was superior to that in 15% (v/v) CPA for 5 min for achievement of high survival rates irrespective of the pCPA combination used. In Experiment 4, when equilibration was performed in 4% EG + PG for 5 min, 15 min or 25 min, there was no difference in oocyte survival and subsequent embryo development after vitrification and warming; however, the developmental competence of cleaved embryos was tendentiously reduced when equilibration was performed for 25 min. In conclusion, trehalose and sucrose were equally effective in facilitating vitrification, and the optimum pCPA treatment was 5–15 min equilibration in 4% (v/v) of EG + PG followed by vitrification in 35% (v/v) EG + PG.  相似文献   

Cytoskeletal and mitochondrial properties of bovine oocytes obtained by Ovum Pick‐Up: the effects of follicle stimulation and in vitro maturation          下载免费PDF全文

Tamás Somfai  Satoko Matoba  Yasushi Inaba  Michiko Nakai  Kei Imai  Takashi Nagai  Masaya Geshi 《Animal Science Journal》2015,86(12):970-980

Follicle stimulation by follicular stimulating hormone (FSH) is known to improve developmental competence of bovine oocytes obtained by Ovum Pick‐Up (OPU); however, the exact factors in oocytes affected by this treatment have remained unclear. We compared in vitro matured (IVM) oocytes obtained at the immature stage from cows by OPU either without or with stimulation with FSH (non‐stimulated and stimulated OPU, respectively) to those obtained by superstimulation and in vivo maturation in terms of cytoskeleton morphology, mitochondrial distribution, intracellular adenosine triphosphate (ATP) content and H₂O₂ levels at the metaphase‐II stage and intracellular Ca²⁺ levels after in vitro fertilization (IVF). Confocal microscopy after immunostaining revealed reduced size of the meiotic spindle, associated with increased tendencies of microfilament degradation and insufficient mitochondrial re‐distribution in non‐stimulated OPU‐derived IVM oocytes compared with those collected by stimulated OPU, which in turn resembled in vivo matured oocytes. However, there was no difference in mitochondrial functions between oocytes obtained by stimulated or non‐stimulated OPU in terms of ATP content, cytoplasmic H₂O₂ levels, base Ca²⁺ levels and the frequencies and amplitudes of Ca²⁺ oscillations after IVF. Larger size of metaphase spindles in oocytes obtained by stimulated OPU may reflect and potentially contribute to their high developmental competence.  相似文献   

Effects of Foliar Biofertilizer Sprays on Nutrient Uptake,Yield, and Quality Parameters of Blaufrankish (Vitis vinifera L.) Grapes     

Péter Tamás Nagy  Tamás Pintér 《Communications in Soil Science and Plant Analysis》2015,46(4):219-227

Nowadays the main task of scientists is to find natural ways of improving plant productivity that lead to environmentally friendly agriculture. Biofertilizers have a great potential to achieve this aim but unfortunately there is little information about their application in grape growing in Hungary. For this reason, a foliar nutrition experiment was conducted to investigate the effect of two biofertilizers (an algae product and a biostimulator, containing amino acids) on yield, leaf nutrient concentration, and quality parameters of Blaufrankish grape variety. The study was conducted in 2012 at Noszvaj in northeastern Hungary in a 24-year-old grapevine plantation on cv. Blaufrankish. Treatments (application time and doses) were adjusted to the phenological phases of grapevine. Effect of treatments was monitored by soil and leaf analysis, grape quality measurements, and field observations. Treatments increased the yield but did not affect the fruit quality compared to the control. The applied products significantly increased the bunch weight and the size of berries. Applied biofertilizers had no effect on leaf nutrient concentration. According to our field observations, it seemed that treated vines had larger and greener leaves.  相似文献   

Rationale for development of a synthetic vaccine against Plasmodium falciparum malaria   总被引：27，自引：0，他引：27  

F Zavala  J P Tam  M R Hollingdale  A H Cochrane  I Quakyi  R S Nussenzweig  V Nussenzweig 《Science (New York, N.Y.)》1985,228(4706):1436-1440

Protective immunity against malaria can be obtained by vaccination with irradiated sporozoites. The protective antigens known as circumsporozoite (CS) proteins, are polypeptides that cover the surface membrane of the parasite. The CS proteins contain species-specific immunodominant epitopes formed by tandem repeated sequences of amino acids. Here it is shown that the dominant epitope of Plasmodium falciparum is contained in the synthetic dodecapeptide Asn-Ala-Asn-Pro-Asn-Ala-Asn-Pro-Asn-Ala-Pro or (NANP)3. Monoclonal antibodies and most or all polyclonal human antibodies to the sporozoites react with (NANP)3, and polyclonal antibodies raised against the synthetic peptide (NANP)3 react with the surface of the parasite and neutralize its infectivity. Since (NANP)3 repeats are present in CS proteins of P. falciparum from many parts of the world, this epitope is a logical target for vaccine development.  相似文献   

Biodiversity and Biomass Production of Weeds in a Long-Term Fertilization Experiment     

Éva Lehoczky  Gellért Gólya  János Tamás  Tamás Németh 《Communications in Soil Science and Plant Analysis》2015,46(4):390-398

A field experiment was carried out to study the influence of nitrogen (N), phosphorus (P), and potassium (K) nutrient supply on weed flora in maize. The investigations were conducted in a long-term fertilization experiment launched in 2003 on a loamy chernozem soil with lime deposits, in Fejér County, Hungary. The composition, biomass weight, and density of weeds were determined in relation to different nutrient supplies. Seventy-five percent of weeds consisted of three species: Ambrosia artemisiifolia L., Datura stramonium L., and Helianthus annuus L. Density of weeds varied relative to the different nutrient treatments, with a range of 82–131 plants m^?2. The total weed density was significantly lower by 19.9–37.8 percent in the N-containing treatments (NP, NPK) than in non-N treatments. The density of the nitrophil D. stramonium L., Chenopodium album L., Chenopodium hybridum L., and Amaranthus blitoides S. Watson was higher when N supply was greater.  相似文献   

Identification, cloning and characterisation of a HMW-glutenin gene from an old Hungarian wheat variety, Bánkúti 1201     

A. Juhász  L. Tamás  I. Karsai  G. Vida  L. Láng  Z. Bedő 《Euphytica》2001,119(1-2):75-79

Despite its good functional properties, the varietyBánkúti 1201 has been found to possess 2 + 12 or 3 + 12 allelecomposition on chromosome 1D. In order to determine the reason for itsquality traits a gene-specific PCR technique was applied in preliminaryexperiments to examine the HMW glutenin allele composition of thevariety. In the course of the analysis a fragment characteristic ofBánkúti 1201 was identified and the nucleotide sequence wasdetermined. This showed the presence of a 1Ax2^* gene variantwhich, despite near homology, differed from the original 1Ax2^* geneat one important point. At 1181 bp of the 1Ax2^* sequencenucleotide exchange was observed which is the middle nucleotide of theTCT–TGT base triplet, involving the exchange of serine for cysteine. Thegene was designated 1Ax2^*B. The presence of an extrasulphydryl group, like that of the extra cysteine in the 1Dx5 gene,facilitates the formation of further disulphide bonds, might lead to animprovement in gluten quality characters.  相似文献