Search results for "Secondary"
showing 10 items of 1765 documents
Singular integrals on regular curves in the Heisenberg group
2019
Let $\mathbb{H}$ be the first Heisenberg group, and let $k \in C^{\infty}(\mathbb{H} \, \setminus \, \{0\})$ be a kernel which is either odd or horizontally odd, and satisfies $$|\nabla_{\mathbb{H}}^{n}k(p)| \leq C_{n}\|p\|^{-1 - n}, \qquad p \in \mathbb{H} \, \setminus \, \{0\}, \, n \geq 0.$$ The simplest examples include certain Riesz-type kernels first considered by Chousionis and Mattila, and the horizontally odd kernel $k(p) = \nabla_{\mathbb{H}} \log \|p\|$. We prove that convolution with $k$, as above, yields an $L^{2}$-bounded operator on regular curves in $\mathbb{H}$. This extends a theorem of G. David to the Heisenberg group. As a corollary of our main result, we infer that all …
Existence of doubling measures via generalised nested cubes
2012
Working on doubling metric spaces, we construct generalised dyadic cubes adapting ultrametric structure. If the space is complete, then the existence of such cubes and the mass distribution principle lead into a simple proof for the existence of doubling measures. As an application, we show that for each $\epsilon>0$ there is a doubling measure having full measure on a set of packing dimension at most $\epsilon$.
Morphogenetic (Mucin Expression) as Well as Potential Anti-Corona Viral Activity of the Marine Secondary Metabolite Polyphosphate on A549 Cells
2020
The mucus layer of the nasopharynx and bronchial epithelium has a barrier function against inhaled pathogens such as the coronavirus SARS-CoV-2. We recently found that inorganic polyphosphate (polyP), a physiological, metabolic energy (ATP)-providing polymer released from blood platelets, blocks the binding of the receptor binding domain (RBD) to the cellular ACE2 receptor in vitro. PolyP is a marine natural product and is abundantly present in marine bacteria. Now, we have approached the in vivo situation by studying the effect of polyP on the human alveolar basal epithelial A549 cells in a mucus-like mucin environment. These cells express mucins as well as the ectoenzymes alkaline phospha…
Argumentation Skills as Prerequisites for Collaborative Learning Among Finnish, French and English Secondary School Students.
2005
International audience; Argumentation skills of secondary school students were evaluated in Finland (n = 290), France (n = 54), and England (n = 41). The data were collected from 4 tasks comprising 7 variables. The results indicated that most of the students had correctly justified arguments and conclusions, and composed clear claims and relevant arguments. However, many students had difficulties in recognising the main claim and arguments for it in an expository text, and in commenting analytically on an argumentative text. Thus the students possessed the prerequisites for argumentative reasoning and writing but need further practice in analytical and critical reading.
Student evaluations of the credibility and argumentation of online sources
2021
This study investigated upper secondary school students’ skills in evaluating the credibility and argumentative content of a blog text and a YouTube video. Both sources concerned child vaccination, the blog text opposing and the YouTube video supporting it. Students rated each source as credible, fairly credible or non-credible, justified their ratings, and analyzed the argumentation of both sources. Their justifications were analyzed for trustworthiness and expertise and their argument analyses for identification of the main position of the source and the reasons supporting it. Students’ justification skills proved fairly weak, and they also struggled with recognizing unbalanced argumentat…
Life Cycle Assessment of Asphalt Mixtures with WMR
2023
This study aimed at providing pavement specialists with international average values of greenhouse gas emissions (GHG) and energy consumption related to the manufacturing of asphalt mixtures (cradle-to-gate), with and without waste and secondary materials for roads (WMRs). In order to achieve this goal, TG leaders first referred to current standards to define a methodology for obtaining benchmark values according to ISO 21678:2020. Then, a data collection tool was designed and provided to a group of international partners to build a life cycle inventory for asphalt mixtures including data from materials up to plant manufacturing (A1–A3). Partners were asked to provide information for any ty…
Aircraft-based observations of isoprene-epoxydiol-derived secondary organic aerosol (IEPOX-SOA) in the tropical upper troposphere over the Amazon reg…
2018
During the ACRIDICON-CHUVA field project (September–October 2014; based in Manaus, Brazil) aircraft-based in situ measurements of aerosol chemical composition were conducted in the tropical troposphere over the Amazon using the High Altitude and Long Range Research Aircraft (HALO), covering altitudes from the boundary layer (BL) height up to 14.4 km. The submicron non-refractory aerosol was characterized by flash-vaporization/electron impact-ionization aerosol particle mass spectrometry. The results show that significant secondary organic aerosol (SOA) formation by isoprene oxidation products occurs in the upper troposphere (UT), leading to increased organic aerosol mass concentratio…
Study on ambient concentrations of PM10, PM10-2.5, PM2.5 and gaseous pollutants. Trace elements and chemical speciation of atmospheric particulates
2010
Abstract This study provides the first comprehensive report on mass concentrations of particulate matter of various sizes, inorganic and organic gas concentrations monitored at three sampling sites in the city of Palermo (Sicily, Italy). It also provides information on the water-soluble species and trace elements. A total of 2054 PM10 (1333) and PM2.5 (721) daily measurements were collected from November 2006 to February 2008. The highest mass concentrations were observed at the urban stations, average values being about two times higher than those at the suburban (control) site. Time variations in PM10 and also PM10–2.5 were observed at the urban stations, the highest concentrations being …
General overview: European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI)-integrating aerosol research from nano …
2011
In this paper we describe and summarize the main achievements of the European Aerosol Cloud Climate and Air Quality Interactions project (EUCAARI). EUCAARI started on 1 January 2007 and ended on 31 December 2010 leaving a rich legacy including: (a) a comprehensive database with a year of observations of the physical, chemical and optical properties of aerosol particles over Europe, (b) comprehensive aerosol measurements in four developing countries, (c) a database of airborne measurements of aerosols and clouds over Europe during May 2008, (d) comprehensive modeling tools to study aerosol processes fron nano to global scale and their effects on climate and air quality. In addition a new Pan…
Determination of alkylamines in atmospheric aerosol particles: a comparison of gas chromatography–mass spectrometry and ion chromatography approaches
2014
Abstract. In recent years low molecular weight alkylamines have been recognized to play an important role in particle formation and growth in the lower atmosphere. However, major uncertainties are associated with their atmospheric processes, sources and sinks, mostly due to the lack of ambient measurements and the difficulties in accurate quantification of alkylamines at trace level. In this study, we present the evaluation and optimization of two analytical approaches, i.e., gas chromatography–mass spectrometry (GC-MS) and ion chromatography (IC), for the determination of alkylamines in aerosol particles. Alkylamines were converted to carbamates through derivatization with isobutyl chlorof…