Search results for "HB"

Faraday patterns in bose-Einstein condensates.

2002

Temporal periodic modulation of the interatomic s-wave scattering length in Bose-Einstein condensates is shown to excite subharmonic patterns of atom density through a parametric resonance. The dominating wavelength of the spatial structures is shown to be primarily selected by the excitation frequency but also affected by the depth of the spatial modulation via a nonlinear resonance. These phenomena represent macroscopic quantum analogues of the Faraday waves excited in vertically shaken liquids.

Pairing gap and in-gap excitations in trapped fermionic superfluids

2004

We consider trapped atomic Fermi gases with Feshbach-resonance enhanced interactions in pseudogap and superfluid temperatures. We calculate the spectrum of RF(or laser)-excitations for transitions that transfer atoms out of the superfluid state. The spectrum displays the pairing gap and also the contribution of unpaired atoms, i.e. in-gap excitations. The results support the conclusion that a superfluid, where pairing is a many-body effect, was observed in recent experiments on RF spectroscopy of the pairing gap.

Social media for universities’ strategic communication: how Nigerian universities use Facebook

2020

A university has many stakeholders with varying interests and commitments. Several studies have examined modes and methods of HEIs communication with stakeholders. To the best of our knowledge, it is not evident in the literature how the engagement between universities and their stakeholders proceeds on the social media platforms particularly from a developing country perspective. This study employed stakeholder theory to give newer understanding to social media marketing as a strategy to reach university stakeholders and utilised an inductive, generic, qualitative approach in a netnography context to achieve the aim of this study. Theoretically, this chapter makes three key contributions. …

Vortrag über den Entwurf einer Centralschule für Handel und Gewerbe im Riga, gehalten am 19. Februar 1859 im Locale des Rigaschen Börsen-Comité's

1859

An efficient algorithm for stopping on a sink in a directed graph

2013

Abstract Vertices of an unknown directed graph of order n are revealed one by one in some random permutation. At each point, we know the subgraph induced by the revealed vertices. Our goal is to stop on a sink, a vertex with no out-neighbors. We show that if a sink exists this can be achieved with probability Θ ( 1 / n ) , which is best possible.

Spread of hepatitis B virus infection among family contacts of asymptomatic HBsAg carriers

1979

Family members of 34 asymptomatic HBsAg carriers were tested for different hepatitis B virus (HBV) markers. Among 67 family members tested 24 (36%) presented signs of a past or ongoing HBV-infection. Spread of HBV-infection was particularly high in those families in which the HBsAg carrier was positive for HBeAg and Dane particle-associated DNA polymerase activity. Non-parenteral “horizontal” transmission of HBV among spouses and brothers and sisters and probably parenteral vertical transmission of HBV from carrier mothers to their infants occurred in approximately the same frequency. Fathers transmitted HBV unfrequently to their offsprings. The results show that the risk to acquire a HBV-i…

Combining feature extraction and expansion to improve classification based similarity learning

2017

Abstract Metric learning has been shown to outperform standard classification based similarity learning in a number of different contexts. In this paper, we show that the performance of classification similarity learning strongly depends on the data format used to learn the model. We then present an Enriched Classification Similarity Learning method that follows a hybrid approach that combines both feature extraction and feature expansion. In particular, we propose a data transformation and the use of a set of standard distances to supplement the information provided by the feature vectors of the training samples. The method is compared to state-of-the-art feature extraction and metric lear…

Classification of spatio-temporal point pattern in the presence of clutter using K-th nearest neighbour distances

2019

In a point process spatio-temporal framework, we consider the problem of features detection in the presence of clutters. We extend the methodology of Byers and Raftery (1998) to the spatio-temporal context by considering the properties of the K-th nearest-neighbour distances. We make use of the spatio-temporal distance based on the Euclidean norm where the temporal term is properly weighted. We show the form of the probability distributions of such K-th nearest-neighbour distance. A mixture distribution, whose parameters are estimated with an EM algorithm, is used to classify points into clutters or features. We assess the performance of the proposed approach with a simulation study, togeth…

Financial Management as a Tool for Achieving Stable Firm Growth

2016

Abstract The purpose of this study is to show that financial management in the firm is a tool for achieving stable firm growth and long-term firm stability while problems in firm financial management lead to the inability of firms to ensure sustainable growth of their value. This problem is relevant for firms in all countries. The main objectives of this paper are: to analyse dynamics of value of the largest Latvian firms, to determine the drivers of these dynamics and to establish the main problems slowing the growth of firm value, which are related to the drawbacks in financial management, and to provide suggestions for solving these problems. This study analyses financial management proc…

A two-armed bandit collective for hierarchical examplar based mining of frequent itemsets with applications to intrusion detection

2014

Published version of a chapter in the book: Transactions on Computational Collective Intelligence XIV. Also available from the publisher at: http://dx.doi.org/10.1007/978-3-662-44509-9_1 In this paper we address the above problem by posing frequent item-set mining as a collection of interrelated two-armed bandit problems. We seek to find itemsets that frequently appear as subsets in a stream of itemsets, with the frequency being constrained to support granularity requirements. Starting from a randomly or manually selected examplar itemset, a collective of Tsetlin automata based two-armed bandit players - one automaton for each item in the examplar - learns which items should be included in …