130,425 research outputs found
Preliminary investigation of Osmia cornuta Latr. (Hymenoptera Megachilidae) as a potential pollinator for Blackberry (Rubus fruticosus L.) under confined environment.
No full textLeptospira spp. and Brucella ovis seroprevalence in sheep: Preliminary results of one year surveillance program
No full textIn order to assess the diffusion of brucellosis by Brucella ovis and leptospirosis in sheep flocks in Tuscany, 410 blood samples were collected from males of 76 breeding farms from January to December 2015. All sera resulted negative for B. ovis. A percentage of 17.80% sera was found positive for Leptospira spp. Among all breeding farms, 34.21% resulted positive. The most represented serovars were Pomona (6.34%), Hardjo (4.14%), Grippotyphosa (3.17%) and Bratislava (1.70%). The highest antibody titers were detected for serovar Hardjo (1:25600) and serovars Pomona and Grippotyphosa (1:1600). These results confirm the role of sheep as maintenance host for serovar Hardjo and highlight the spreading of serovar Grippotyphosa in the study area. Constant field investigation, especially on farm animals, could be useful to determine trends and diffusion of some occupational re-emerging diseases, such as leptospirosis
DNA isolation methods for Nanopore sequencing of the Streptococcus mitis genome
No full textStreptococcus mitis is a Gram-positive bacterium, member of the oral commensal microbiota, which can occasionally be the etiologic agent of diseases such as infective endocarditis, bacteraemia and septicaemia. The highly recombinogenic and repetitive nature of the S. mitis genome impairs the assembly of a complete genome relying only on short sequencing reads. Oxford Nanopore sequencing can overcome this limitation by generating long reads, enabling the resolution of genomic repeated regions and the assembly of a complete genome sequence. Since the output of a Nanopore sequencing run is strongly influenced by genomic DNA quality and molecular weight, the DNA isolation is the crucial step for an optimal sequencing run. In the present work, we have set up and compared three DNA isolation methods on two S. mitis strains, evaluating their capability of preserving genomic DNA integrity and purity. Sequencing of DNA isolated with a mechanical lysis-based method, despite being cheaper and quicker, did not generate ultra-long reads (maximum read length of 59516 bases) and did not allow the assembly of a circular complete genome. Two methods based on enzymatic lysis of the bacterial cell wall, followed by either (i) a modified CTAB DNA isolation procedure, or (ii) a DNA purification after osmotic lysis of the protoplasts allowed the sequencing of ultra-long reads up to 107294 and 181199 bases in length, respectively. The reconstruction of a circular complete genome was possible sequencing DNAs isolated using the enzymatic lysis-based methods
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Analysis of inorganic markers of stress in natural and genetically modified plants in the presence of chemical and physical stresses
No full text"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Ecophysiological responses of Fagus sylvatica L. seedlings to changing light conditions. II. The interaction of clearing, gap and understory environments with soil fertility.
No full textThe survival and growth of natural beech regeneration after canopy removal is variable and little is known about ecophysiological mechanisms of these responses. Biomass, nonstructural carbohydrate levels and nitrogen concentrations were measured in an Italian population of European beech seedlings. Seedlings were container-grown in two types of soil, organic and mineral, collected at the study site. The seedlings were grown under three light treatments: under full beech canopy (understory), exposed to full sun only during midday (gap) and under full sun (clearing). Leaf gas exchange and chlorophyll a fluorescence parameters were measured and then foliar analyses were conducted for chlorophyll, phenolic and tannin levels. Biomass and allocation were significantly affected by light and soil treatments. The clearing seedlings and those in organic soil were larger than seedlings in the other light treatments or soil type. Total nonstructural carbohydrate concentrations were lower in the understory seedlings and significant differences between soil types were present in the gap and clearing seedlings. Nitrogen concentrations were higher in the understory seedlings and those growing in the organic soil compared to the other treatments. Gas exchange rates were highest in clearing and the organic soil seedlings. Gap seedlings exhibited photosynthetic acclimation that allowed them to utilize high light of midday and any sunflecks during the morning and afternoon. Relative fluorescence was significantly influenced by both light treatment and soil type, with the highest values observed in the gap seedlings. Light response curves showed decreasing apparent maximum quantum efficiency from the understory to clearing, while maximum photosynthetic rate was highest in the gap seedlings. Chlorophyll concentration was highest in understory seedlings and those growing in organic soil and higher in seedlings growing in organic than in mineral soil. Both foliar tannin and phenolic levels were highest in clearing seedlings, and only tannin concentrations were affected by soil type. Understory seedlings had the highest mortality and insect herbivory; the latter was found to be inversely related to tannin concentration. Overall, growth and photosynthesis in beech seedlings responded positively to high light associated with small canopy gaps. Organic soil increased seedling size, particularly in the gap and clearing environments. We conclude that forest gaps are favorable for photosynthesis and growth of European beech seedlings
Surface chemistry of Ni-free stainless steel
No full textNowadays there is a strong demand to replace Ni-Cr steels used for biomedical applications such as brackets in orthodoncy with a new generation of more biocompatible austenitic, nickel-free alloys. The aim of this work is the assessment of the substances that leach from the steel and the investigation of the growth and stability of the surface film formed on DIN 1.4456 Ni-free stainless steel in artificial saliva (pH 7.9) at 37°C by electrochemistry and XPS surface analyses. So far the data available in the literature refer to tests carried out at ambient temperature. Previous works of this research group [1] have shown that Ni-free stainless steel immersed into 0.1M NaOH solution form a passive film that changes its composition with immersion time. These results are confirmed in the present investigation: the corrosion current values decrease from 1 to 24 hours exposure time (see Table) to the solution and the passive film becomes more protective and thick. XPS provides evidence that the surface film formed is mainly composed of oxides and hydroxides of Fe (III), Cr(III) and Mn (see figure).
Fe (II) amount in the passive film decreases with immersion time in favor of Fe (III) oxide (Fe2O3) and hydroxide (FeOOH). Cr as well is first present as Cr2O3 and turns to Cr(OH)3 for longer contact time to artificial saliva.
The results will be discussed in comparison with those obtained on at ambient temperature [ref].
References.
1. T. H. Huang, Am. J. Orthod. Dentofac. (2001), 120, 1
2. C.T. Kao, Eur. J. Orthod. (2010), 32, 555-560
3. B. Elsener, Elec. Acta (2011), 56,4489-449
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