Search results for "ample"
showing 10 items of 2398 documents
Counterexamples to the Kneser conjecture in dimension four.
1995
We construct a connected closed orientable smooth four-manifold whose fundamental group is the free product of two non-trivial groups such that it is not homotopy equivalent toM 0#M 1 unlessM 0 orM 1 is homeomorphic toS 4. LetN be the nucleus of the minimal elliptic Enrique surfaceV 1(2, 2) and putM=N∪ ∂NN. The fundamental group ofM splits as ℤ/2 * ℤ/2. We prove thatM#k(S 2×S2) is diffeomorphic toM 0#M 1 for non-simply connected closed smooth four-manifoldsM 0 andM 1 if and only ifk≥8. On the other hand we show thatM is homeomorphic toM 0#M 1 for closed topological four-manifoldsM 0 andM 1 withπ 1(Mi)=ℤ/2.
Convergence of Markov Chains
2020
We consider a Markov chain X with invariant distribution π and investigate conditions under which the distribution of X n converges to π as n→∞. Essentially it is necessary and sufficient that the state space of the chain cannot be decomposed into subspaces that the chain does not leave, or that are visited by the chain periodically; e.g., only for odd n or only for even n.
Historical Notes on Star Geometry in Mathematics, Art and Nature
2018
Gamma: “I can. Look at this Counterexample 3: a star-polyhedron I shall call it urchin. This consists of 12 star-pentagons. It has 12 vertices, 30 edges, and 12 pentagonal faces-you may check it if you like by counting. Thus the Descartes-Euler thesis is not true at all, since for this polyhedron \(V - E + F = - 6\)”. Delta: “Why do you think that your ‘urchin’ is a polyhedron?” Gamma: “Do you not see? This is a polyhedron, whose faces are the twelve star-pentagons”. Delta: “But then you do not even know what a polygon is! A star-pentagon is certainly not a polygon!”
TERMITE: AnRscript for fast reduction of laser ablation inductively coupled plasma mass spectrometry data and its application to trace element measur…
2017
RATIONALE High spatial resolution Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) determination of trace element concentrations is of great interest for geological and environmental studies. Data reduction is a very important aspect of LA-ICP-MS, and several commercial programs for handling LA-ICPMS trace element data are available. Each of these software packages has its specific advantages and disadvantages. METHODS Here we present TERMITE, an R script for the reduction of LA-ICPMS data, which can reduce both spot and line scan measurements. Several parameters can be adjusted by the user, who does not necessarily need prior knowledge in R. Currently, ten reference m…
DAQs-based wattmeters for high accuracy measurements. Comparison with the Italian power primary standard
2013
Abstract This paper is focused on the use of data acquisition boards (DAQs) for the development of high accuracy PC-based instruments for the measurements of electrical power. The proposed systems are simple, portable and low cost because they are based on commercial data acquisition boards (DAQs) connected to a common personal computer. Data processing is carried out by a commercial software based on an interpolating windowed FFT. In the paper it is shown how the voltage can be sensed directly, thanks to the DAQ input range, thus avoiding expensive voltage dividers. The set up of the DAQs-based solutions is described and the evaluation of their metrological features is made by means of a c…
A cross-cultural analysis of organizational dissent and workplace freedom in five European economies.
2014
Individuals in five European countries—Finland, France, Germany, Spain, and the United Kingdom (n = 1184)—completed a survey exploring the relationship between organizational dissent and workplace freedom of speech. Results revealed workplace freedom of speech is positively correlated with dissent among the entire sample in France and in Germany. Results in Spain were nonsignificant. In the United Kingdom, there was a negative relationship between workplace freedom of speech and dissent. There was a negative relationship between workplace freedom of speech and articulated dissent and a positive relationship with latent dissent in Finland. Moreover, MANCOVA testing showed nationality to have…
The Transcultural Community Resilience Scale: Psychometric Properties and Multinational Validity in the Context of the COVID-19 Pandemic
2021
Few instruments assess community resilience. In the midst of the COVID-19 pandemic, the capacity of communities to support resilience of members deserves to be assessed to develop programs for improving mental health of affected populations. This article presents the development of the Transcultural-Community Resilience Scale (T-CRS), its underlying factorial structure and transcultural validity with a multilingual (English, French, Creole, Kinyarwanda), multinational (DR Congo, Haiti, Rwanda, Togo) and multicultural sample affected by this pandemic. A sample of 1,267 participants (40.9% women) were recruited in the four countries: DRC (n = 626, 43.4% women), Haiti (n = 225, 42.0% women), R…
The Effect of Credit Rating Events on the Emerging CDS Market
2017
We document the cross-border spillover impact of S&P sovereign credit rating events on sovereign CDS using an extensive sample of emerging economies. First, we find on average a competition (imitation) effect of downgrades (upgrades) among emerging portfolios. Results confirms that non-event portfolios responds positively to credit deteriorations in terms of an improvement in sovereign credit risk. Second, the sovereign credit risk of non-event countries within the same portfolio benefit (suffer) from downgrades (upgrades). As expected, this implies a competition effect in terms of sovereign credit risk. Moreover, we find that downgrades are more likely to spill over into other emerging mar…
Technical efficiency and the vertical boundaries of the firm: theory and evidence
2013
This article provides a theoretical and empirical analysis of the relationship between firms’ technical efficiency and the vertical organization of production. Technical inefficiency is explicitly introduced as the source of firms’ heterogeneity in a Bertrand–Nash model of industry competition: the main prediction of the model is that the most efficient firms choose vertical integrated structures and the less-efficient ones choose disintegrated structures. The empirical part of the article rests on a stochastic frontier analysis (SFA) in a sample of about 400 Italian machine tool (MT) builders, and the result supports the prediction of the theoretical model.
The use of complementary alternative medicines in advanced cancer patients followed at home
2021
Objectives: To assess the use of complementary alternative medicines (CAM) in advanced cancer patients followed at home. Methods: A consecutive sample of advanced cancer patients admitted to a home palliative care program was invited to participate in the study in a period of two months. Demographic characteristics, religious belief, education level, diagnosis, and socio-economic condition were recorded. Patients were asked about the use of CAM, considered to be a health-related treatment practiced outside the established health services. Information about CAM indications and those who prescribed or suggested CAM were also collected. Results: Two hundred and eighty-three advanced cancer pat…