159,321 research outputs found
Tephritis azari Mohamadzade Namin & Korneyev
No full textTephritis azari Mohamadzade Namin & Korneyev (Figs. 1 –2, 10– 17) Tephritis azari Mohamadzade & Korneyev 2012: 80. Meterial examined. Type material. Holotype (female): Iran: West Azerbaijan province, 10 km W Ziveh, 2700 m, 37 °08'N, 44 ° 52 'E, 24.vii. 2012 (Mohamadzade & Najarpoor leg.) (JAZM); Paratypes: Azerbaijan: Talysh, vic. Lerik, Dzhoni vil. [=Çoni, 38 ° 36.8 'N 48 ° 30.5 'E, h= 1390 m], 5.vi.1981, 1♀ (V. Ermolenko leg.) (SIZK); Iran: same collection data as in holotype, 3 ♀, 2 ♂; East Azerbaijan Province, Sahand ski resort, 30 km of Tabriz, 37 ° 45.850 ' N 46 ° 30.754 ' E, 2900 m, 30.viii.2011, 1♀, 1 ♂ (Mohamadzade & Najarpoor leg.); Ardabil Province, Sabalan Mountain, 2900 m; 12.vii. 2012, swept from Senecio sp., 1 ♀, 1 ♂ (Mohamadzade & Najarpoor leg.) (JAZM, SIZK and SMNC); Non-type: Sabalan Mountain, 2900 m; 4.vii.2014, 1♂ (Korneyev & Mohamadzade) (SIZK). Distribution. Azerbaijan and Iran (Mohamadzade Namin & Korneyev 2012). Diagnosis. Tephritis azari is similar to T. maccus Hering and T. gharalii sp. nov. in the wing pattern (hyaline basally, with brown radiate pattern on apical two-thirds, and usually with one large hyaline spot in cell r 1), flagellomere 1 pointed, oviscape short, aculeus relatively blunt, with short acute apex and similar spermathecae shape. It differs from both species by the size of the brown ray in cell dm basal to the level of r-m, which is absent or short, usually reaching only the mid-width of cell dm, at most reaching Cu 1 (long, reaching middle of cell cu 1 in T. maccus and T. gharalii).Published as part of Namin, Saeed Mohamadzade, Korneyev, Severyn V., Parchami-Araghi, Mehrdad & Gilasian, Ebrahim, 2015, Revision of the Tephritis maccus species group (Diptera: Tephritidae) with description of a new species from Iran, pp. 589-599 in Zootaxa 3956 (4) on page 591, DOI: 10.11646/zootaxa.3956.4.10, http://zenodo.org/record/23869
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Integrating AI and DTs: challenges and opportunities in railway maintenance application and beyond
No full textIn the last years, there has been a growing interest in the emerging concept of digital twin (DT) as it represents a promising paradigm to continuously monitor cyber–physical systems, as well as to test and validate predictability, safety, and reliability aspects. At the same time, artificial intelligence (AI) is exponentially affirming as an extremely powerful tool when it comes to modeling the behavior of physical assets allowing, de facto, the possibility of making predictions on their potential evolution. However, despite the fact that DTs and AI (and their combination) can act as game-changing technologies in different domains (including the railways), several challenges have to be faced to ensure their effectiveness, especially when dealing with safety-critical systems. This paper provides a narrative review of the scientific literature on DTs for railway maintenance applications, with a special focus on their relationship with AI. The aim is to discuss the opportunities the integration of these two technologies could open in railway maintenance applications (and beyond), while highlighting the main challenges that should be overcome for its effective implementation
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
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
"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.
Semicrystalline polymer deposits on surfaces formed by drop drying
No full textThe deposits formed after the evaporation of aqueous poly(ethylene oxide) (PEO) solution
droplets on hydrophilic glass substrates were investigated, focusing on the influence of initial
solute concentration and polymer molecular weight on the macrostructures and
micro/nanostructures of deposits. Using stereo microscopy and atomic force microscopy (AFM),
along with a mathematical model based on thin-film hydrodynamic theory, the research
experimentally and mathematically investigated how varying initial conditions affect the final
deposition patterns in macro- and micro/nano-scales. Stereo microscopy showed that increasing
the initial solute concentration transformed the deposit’s macrostructure from a ring to a conical
pillar over a puddle-like base, while higher polymer molecular weight reduced stick-slip actions,
altering the macrostructure from multiple semi-concentric rings to a single ring. The AFM study
revealed that the initial solute concentration and the polymer molecular weight significantly
affected the micro/nanostructures in different deposit areas. Deposits contained predominantly
semicrystalline, and occasionally amorphous, micro/nanostructures. The semicrystallites were in
the form of out-of-plane lamellae, requiring high crystallisation driving forces, or in-plane terraces
and spirals, needing lower driving forces. The out-of-plane lamellae varied in size across regions,
being smaller in areas with higher crystallisation driving forces. The mathematical model predicted
the macrostructures of deposits by evaluating the final heights of droplets. The model also
estimated the micro/nanostructures of deposits by analysing the rates of supersaturation
development, which directly impact the crystallisation driving forces across different areas of the
droplets. Overall, the study provided a detailed understanding of how the initial concentration and
molecular weight of polymer influenced the droplet evaporation dynamics and the resulting
deposition patterns, offering valuable insights for applications requiring controlled drying and
deposition processes
Towards AI-assisted digital twins for smart railways: preliminary guideline and reference architecture
No full textIn the last years, there has been a growing interest in the emerging concept of digital twins (DTs) among software engineers and researchers. DTs not only represent a promising paradigm to improve product quality and optimize production processes, but they also may help enhance the predictability and resilience of cyber-physical systems operating in critical contexts. In this work, we investigate the adoption of DTs in the railway sector, focusing in particular on the role of artificial intelligence (AI) technologies as key enablers for building added-value services and applications related to smart decision-making. In this paper, in particular, we address predictive maintenance which represents one of the most promising services benefiting from the combination of DT and AI. To cope with the lack of mature DT development methodologies and standardized frameworks, we detail a workflow for DT design and development specifically tailored to a predictive maintenance scenario and propose a high-level architecture for AI-enabled DTs supporting such workflow
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