Smarandache Non-Associative (SNA-) rings

In this paper we introduce the concept of Smarandache non-associative rings, which we shortly denote as SNA-rings as derived from the general definition of a Smarandache Structure (i.e., a set A embedded with a week structure W such that a proper subset B in A is embedded with a stronger structure S

Photoplethysmography for Quantitative Assessment of Sympathetic Nerve Activity (SNA) During Cold Stress

The differences in the degree of sympathetic nerve activity (SNA) over cutaneous blood vessels, although known to be more prominent in the periphery than the core vasculature, has not been thoroughly investigated quantitatively. Hence, two studies were carried out to investigate the differences in SNA between the periphery and the core during the cold pressor test (CPT) (right-hand immersion in ice water) and cold exposure (whole body exposed to cold air) using photoplethysmography (PPG). Two methods utilizing PPG, namely differential multi-site PTT measurements and low-frequency spectral analysis were explored for quantitative determination of SNA. Each study involved 12 healthy volunteers, and PPG signals were acquired from the right index finger (RIF), left index finger (LIF) (periphery) and the ear canal (core). During CPT, Pulse Transit Time (PTT) was measured to the respective locations and the mean percentage change in PTT during ice immersion at each location was used as an indicator for the extent of SNA. During cold exposure, the low-frequency spectral analysis was performed on the acquired raw PPGs to extract the power of the sympathetic [low-frequency (LF): 0.04–0.15 Hz] and parasympathetic components [high-frequency (HF): 0.15–0.4 Hz]. The ratio of LF/HF components was then used to quantify the differences in the influence of SNA on the peripheral and core circulation. PTT measured from the EC, and the LIF has dropped by 5 and 7%, respectively during ice immersion. The RIF PTT, on the other hand, has dropped significantly (P < 0.05) by 12%. During the cold exposure, the LF/HF power ratio at the finger has increased to 86.4 during the cold exposure from 19.2 at the baseline (statistically significant P = 0.002). While the ear canal LF/HF ratio has decreased to 1.38 during the cold exposure from 1.62 at baseline (P = 0.781). From these observations, it is evident that differential PTT measurements or low-frequency analysis can be used to quantify SNA. The results also demonstrate the effectiveness of the central auto-regulation during both short and long-term stress stimulus as compared to the periphery

Social network analysis of rural medical school immersion in a rural clinical school

Background: The impact of new medical graduates on the social dimensions of the rural medical workforce is yet to be examined. Social Network Analysis (SNA) is able to visualize and measure these dimensions. We apply this method to examine the workforce characteristics of graduates from a representative Australian Rural Clinical School. Methods: Participants were medical graduates of the Rural Clinical School of Western Australia (RCSWA) from the 2001–2014 cohorts, identified as being in rural work in 2017 by the Australian Health Practitioner Regulation Agency. SNA was used to examine the relationships between site of origin and of work destination. Data were entered into UCInet 6 as tied pairs, and visualized using Netdraw. UCINet statistics relating to node centrality were obtained from the node editor. Results: SNA measures showed that the 124 of 709 graduates in rural practice were distributed around Australia, and that their practice was strongly focused on the North, with a clear centre in the remote Western Australian town of Broome. Women were strongly recruited, and were widely distributed. Conclusions: RCSWA appears to be a “weak tie” according to SNA theory: the School attracts graduates to rural nodes where they had only passing prior contact. The multiple activities that comprise the social capital of the most attractive, remote, node demonstrate the clear workforce effects of being a “bridge, broker and boundary spanner” in SNA terms, and add new understanding about recruiting to the rural workforce

Semantic Network Analysis of Ontologies

A key argument for modeling knowledge in ontologies is the easy re-use and re-engineering of the knowledge. However, current ontology engineering tools provide only basic functionalities for analyzing ontologies. Since ontologies can be considered as graphs, graph analysis techniques are a suitable answer for this need. Graph analysis has been performed by sociologists for over 60 years, and resulted in the vivid research area of Social Network Analysis (SNA). While social network structures currently receive high attention in the Semantic Web community, there are only very few SNA applications, and virtually none for analyzing the structure of ontologies. We illustrate the benefits of applying SNA to ontologies and the Semantic Web, and discuss which research topics arise on the edge between the two areas. In particular, we discuss how different notions of centrality describe the core content and structure of an ontology. From the rather simple notion of degree centrality over betweenness centrality to the more complex eigenvector centrality, we illustrate the insights these measures provide on two ontologies, which are different in purpose, scope, and size

Different routes to chaos via strange nonchaotic attractor in a quasiperiodically forced system

This paper focusses attention on the strange nonchaotic attractors (SNA) of a quasiperiodically forced dynamical system. Several routes, including the standard ones by which the appearance of strange nonchaotic attractors takes place, are shown to be realizable in the same model over a two parameters ($f-\epsilon$) domain of the system. In particular, the transition through torus doubling to chaos via SNA, torus breaking to chaos via SNA and period doubling bifurcations of fractal torus are demonstrated with the aid of the two parameter ($f-\epsilon$) phase diagram. More interestingly, in order to approach the strange nonchaotic attractor, the existence of several new bifurcations on the torus corresponding to the novel phenomenon of torus bubbling are described. Particularly, we point out the new routes to chaos, namely, (1) two frequency quasiperiodicity $\to$ torus doubling $\to$ torus merging followed by the gradual fractalization of torus to chaos, (2) two frequency quasiperiodicity $\to$ torus doubling $\to$ wrinkling $\to$ SNA $\to$ chaos $\to$ SNA $\to$ wrinkling $\to$ inverse torus doubling $\to$ torus $\to$ torus bubbles followed by the onset of torus breaking to chaos via SNA or followed by the onset of torus doubling route to chaos via SNA. The existence of the strange nonchaotic attractor is confirmed by calculating several characterizing quantities such as Lyapunov exponents, winding numbers, power spectral measures and dimensions. The mechanism behind the various bifurcations are also briefly discussed.Comment: 12 pages, 12 figures, ReVTeX (to appear in Phys. Rev. E

Constructing SAMs from the SNA

A SAM (Social Accounting Matrix) approach can be an important aid for the modelling of economic policy and a valuable support in the decision-making process, since it provides a description of the measurable part of a society’s activity. Richard Stone made the first and most fundamental contribution to the System of National Accounts (SNA), implemented by the United Nations. Benefiting from successive improved versions since 1953, this system has defined the rules for using the above-mentioned measurement tool. In turn, statistical offices have considered these rules and adapted them to their specific realities, thus defining their own systems, which they have then used as guidelines for measuring the activity of their countries or groups of countries. With these successive improvements, as embodied in the SNA’s latest version from 2008, the description of the activity of a society, its specific characteristics and the problems that it faces have become more realistic. Therefore, the use of the SNA in a SAM-based approach will certainly contribute towards a better modelling of economic policy. Numerical and algebraic versions of the SAM will be examined, with special attention being paid to the former and to the method of its construction from the SNA. Its basic structure and its consistency within the whole system will be studied, as well as any possible disaggregations, extensions, aggregates, indicators, and balances that can be calculated. Other aspects beyond that basic structure will also be examined. An application will be made to Portugal.Social Accounting Matrix; National Accounts; Economic Modelling; Socio-Economic Modelling Classification-C82; E01; E61

Important Structural Linkages in the Process of Income Circulation Defined by SAMs

The main aim of this paper is to present the analytical possibilities offered by Social Accounting Matrices as regards economic policy. These matrices are synthetic presentations of income flows in the economy, described by the international statistical system - System of National Accounts (SNA). Comparative analyses presented in the paper are based on the structure of transactions observed in SNA for three years (2002, 2007, 2012) for selected countries (Germany, Spain, Poland, Bulgaria). The analysis includes a comparative study of the expenditure and income structure of individual institutional sectors, SAM multipliers as an important analytical tool, and the importance of SNA transactions, evaluated by how their changes influence multipliers.Głównym celem artykułu jest przestawienie wybranych możliwości analitycznych - w szczególności w zakresie polityki ekonomicznej - jakie stwarzają macierze rachunkowości społecznej (SAM). Macierze te są syntetycznym opisem cyrkulacji dochodów w gospodarce prezentowanym przez system międzynarodowej sprawozdawczości statystycznej - System Rachunków Narodowych. Przedstawiona w artykule analiza porównawcza opiera się na strukturach transakcji obserwowanych w SRN w trzech latach (2002, 2007, 2012) w wybranych krajach (w Niemczech, Hiszpanii, Polsce i Bułgarii). Analiza zawiera badanie porównawcze struktury wydatków i dochodów poszczególnych sektorów instytucjonalnych oraz mnożników SAM jako ważnego narzędzia analitycznego, a także ocenę ważności transakcji w SRN poprzez badanie wpływu ich zmian na zmiany mnożników

Exploring internal child sex trafficking networks using social network analysis

This article explores the potential of social network analysis as a tool in supporting the investigation of internal child sex trafficking in the UK. In doing so, it uses only data, software, and training already available to UK police. Data from two major operations are analysed using in-built centrality metrics, designed to measure a network’s overarching structural properties and identify particularly powerful individuals. This work addresses victim networks alongside offender networks. The insights generated by SNA inform ideas for targeted interventions based on the principles of Situational Crime Prevention. These harm-reduction initiatives go beyond traditional enforcement to cover prevention, disruption, prosecution, etc. This article ends by discussing how SNA can be applied and further developed by frontline policing, strategic policing, prosecution, and policy and research