Search results for "points"

Multiple solutions for a Sturm-Liouville problem with mixed boundary conditions

2010

When the Blockchain Does Not Block: On Hackings and Uncertainty in the Cryptocurrency Market

2019

A total of 1.1 million bitcoin were stolen in the 2013–2017 period. Noting that the average price for Bitcoin in 2018 was USD 7,572 the corresponding monetary equivalent of losses is USD 8.9 billion which strongly shows the societal impact of this criminal activity. Investigating the response of the uncertainty of Bitcoin when hacking incidents occur, the results of this study point toward a delayed response in volatility. The volatility increases significantly only at day t+5. Incidents of hacking that occur in the Bitcoin market affect uncertainty for another cryptocurrency Ethereum too. Again, the evidence suggests a delayed response. However, Bitcoin and Ethereum do not exhibit asymmetr…

Speculation and Lottery-Like Demand in Cryptocurrency Markets

2020

This is the first paper that explores lottery-like demand in cryptocurrency markets. Since recent research provides evidence that cryptocurrency returns are rather short-memory processes in their nature, we modify Bali et al.’s (2011, 2017) MAX measure and employ a weekly forecast horizon and last week’s daily log-returns for calculating the metric for our portfolio sorts. From an econometric point of view, this study proposes statistical tests that are robust to unknown dynamic dependency structures in the cryptocurrency data. Our results show that average raw and risk adjusted return differences between cryptocurrencies in the lowest and highest MAX deciles exceed 1.50% per week. These re…

Usage des points massiques et des courbes de Bézier pour la modélisation des cubiques

2017

International audience; Cet article étend l'étude des points singuliers et des points d'inflexion des courbes rationnelles cubiques en s'ins-pirant de la méthode proposée par M. Sakai dans le cadre des points massiques. L'intérêt des points massiques est de généraliser le tracé des courbes admettant des points doubles et de contrôler sans calcul supplémentaire l'en-semble des fonctions algébriques cubiques. Un exemple d'application est la réalisation de lettre à l'anglaise ou lettre manuscrite. Les courbes de Bézier permettent d'approcher des profils complexes, le travail présenté permet d'aborder de la même manière l'ensemble des courbes, ce que ne permet pas les splines cubiques d'Hermite.

Points massiques, cubiques Bézier rationnelles et leur points singuliers

2018

National audience; Cet articleétend l'étude des points singuliers des courbes rationnelles cubiques. Ellle porte sur les points d'inflexion, les points doubles et points de rebroussement. Les courbes cubiques rationnelleś etudiées sont décrites au moyen de la technique des points massiques. Un point massique est soit un point pondéré soit un vecteur pur. Il prend le statut de point de contrôle pour une représentation pa-ramétrique exploitable sur ordinateur dans le domaine de la géométrie de la Conception Assistée par Ordinateur. L'intérêt des points massiques est de pouvoir généraliser le tracé des courbes admettant des points doubles et de contrôler sans calcul supplémentaire l'ensemble d…

La política de inmigración en la Unión Europea. Desde tres claves

2005

The European Union's immigration policy regarding the control and management of migratory flow, can be seen from many viewpoints. Of these, three are of particular interest. Firstly, the economic aspect, which is based on reducing the figure of the immigrant to a worker, taking into account the conditions and protection of the European Community's employment market. Secondly, the defensive aspect, which emphasises the need to secure frontiers vulnerable to immigrant migration, in order to ensure both security and law and order. Lastly the social aspect, which focuses on the aim for European homogeneity a reference point for the implementation of this policy and for the need to integrate imm…

Minimal unit vector fields

2002

We compute the first variation of the functional that assigns each unit vector field the volume of its image in the unit tangent bundle. It is shown that critical points are exactly those vector fields that determine a minimal immersion. We also find a necessary and sufficient condition that a vector field, defined in an open manifold, must fulfill to be minimal, and obtain a simpler equivalent condition when the vector field is Killing. The condition is fulfilled, in particular, by the characteristic vector field of a Sasakian manifold and by Hopf vector fields on spheres.

The minimal free resolution of fat almost complete intersections in ℙ1 x ℙ1

2017

AbstractA current research theme is to compare symbolic powers of an ideal I with the regular powers of I. In this paper, we focus on the case where I = IX is an ideal deûning an almost complete intersection (ACI) set of points X in ℙ1 × ℙ1. In particular, we describe a minimal free bigraded resolution of a non-arithmetically Cohen-Macaulay (also non-homogeneous) set 𝒵 of fat points whose support is an ACI, generalizing an earlier result of Cooper et al. for homogeneous sets of triple points. We call 𝒵 a fat ACI.We also show that its symbolic and ordinary powers are equal, i.e, .

How Are Negative Customer Experiences Formed? A Qualitative Study of Customers’ Online Shopping Journeys

2019

This study investigates how negative customer experiences are formed during customers’ online shopping journeys. A qualitative, in-depth dataset collected from 34 participants was employed to identify negatively perceived touchpoints that contribute to the customer experience in a negative way. The findings reveal that negative touchpoints are experienced during customers’ entire journeys, particularly after a purchase is completed. We identified 152 negative touchpoints from the data, of which 53 were experienced during search and consideration, 35 when finalizing a purchase, 33 during delivery, and 31 during after-sales interactions with the company. Within these four main categories, 20 …

Miltirone Induces G2/M Cell Cycle Arrest and Apoptosis in CCRF-CEM Acute Lymphoblastic Leukemia Cells

2015

Miltirone (1) is a diterpene quinone extracted from a well-known Chinese traditional herb (Salvia miltiorrhiza). We investigated the cytotoxic effects of miltirone toward sensitive and multidrug-resistant acute lymphoblastic leukemia cell lines. Miltirone inhibited multidrug-resistant P-glycoprotein (P-gp)-overexpressing CEM/ADR5000 cells better than drug-sensitive CCRF-CEM wild-type cells, a phenomenon termed collateral sensitivity. Flow cytometric analyses revealed that miltirone induced G2/M arrest and apoptosis. Furthermore, miltirone stimulated reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) disruption, which in turn induced DNA damage and activation…