1,033 research outputs found
Intelligent Financial Fraud Detection Practices: An Investigation
Financial fraud is an issue with far reaching consequences in the finance
industry, government, corporate sectors, and for ordinary consumers. Increasing
dependence on new technologies such as cloud and mobile computing in recent
years has compounded the problem. Traditional methods of detection involve
extensive use of auditing, where a trained individual manually observes reports
or transactions in an attempt to discover fraudulent behaviour. This method is
not only time consuming, expensive and inaccurate, but in the age of big data
it is also impractical. Not surprisingly, financial institutions have turned to
automated processes using statistical and computational methods. This paper
presents a comprehensive investigation on financial fraud detection practices
using such data mining methods, with a particular focus on computational
intelligence-based techniques. Classification of the practices based on key
aspects such as detection algorithm used, fraud type investigated, and success
rate have been covered. Issues and challenges associated with the current
practices and potential future direction of research have also been identified.Comment: Proceedings of the 10th International Conference on Security and
Privacy in Communication Networks (SecureComm 2014
Designing Excited States: Theory-Guided Access to Efficient Photosensitizers for Photodynamic Action
Cataloged from PDF version of article.The in silico design of tetraradical S 1 states was validated experimentally through synthesis, followed by characterization including phosphorescence measurements, use of trap molecules, and cell culture studies, leading to a series of orthogonal dimers of Bodipy chromophores with remarkable singlet oxygen efficiencies (see picture). A new path for the rational development of efficient photosensitizers is thus revealed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Collisional and thermal ionization of sodium Rydberg atoms I. Experiment for nS and nD atoms with n=8-20
Collisional and thermal ionization of sodium nS and nD Rydberg atoms with
n=8-20 has been studied. The experiments were performed using a two-step pulsed
laser excitation in an effusive atomic beam at atom density of about 2 10^{10}
cm^{-3}. Molecular and atomic ions from associative, Penning, and thermal
ionization processes were detected. It has been found that the atomic ions were
created mainly due to photoionization of Rydberg atoms by photons of blackbody
radiation at the ambient temperature of 300K. Blackbody ionization rates and
effective lifetimes of Rydberg states of interest were determined. The
molecular ions were found to be from associative ionization in Na(nL)+Na(3S)
collisions. Rate constants of associative ionization have been measured using
an original method based on relative measurements of Na_{2}^{+} and Na^{+} ion
signals.Comment: 23 pages, 10 figure
Inverse magnetocaloric effect in ferromagnetic Ni-Mn-Sn alloys
The magnetocaloric effect (MCE) in paramagnetic materials has been widely
used for attaining very low temperatures by applying a magnetic field
isothermally and removing it adiabatically. The effect can be exploited also
for room temperature refrigeration by using recently discovered giant MCE
materials. In this letter, we report on an inverse situation in Ni-Mn-Sn
alloys, whereby applying a magnetic field adiabatically, rather than removing
it, causes the sample to cool. This has been known to occur in some
intermetallic compounds, for which a moderate entropy increase can be induced
when a field is applied, thus giving rise to an inverse magnetocaloric effect.
However, the entropy change found for some ferromagnetic Ni-Mn-Sn alloys is
just as large as that reported for giant MCE materials, but with opposite sign.
The giant inverse MCE has its origin in a martensitic phase transformation that
modifies the magnetic exchange interactions due to the change in the lattice
parameters.Comment: 12 pages, 4 figures, to appear in Nature Materials (online published,
15 May 2005
Scaling and Formulary cross sections for ion-atom impact ionization
The values of ion-atom ionization cross sections are frequently needed for
many applications that utilize the propagation of fast ions through matter.
When experimental data and theoretical calculations are not available,
approximate formulas are frequently used. This paper briefly summarizes the
most important theoretical results and approaches to cross section calculations
in order to place the discussion in historical perspective and offer a concise
introduction to the topic. Based on experimental data and theoretical
predictions, a new fit for ionization cross sections is proposed. The range of
validity and accuracy of several frequently used approximations (classical
trajectory, the Born approximation, and so forth) are discussed using, as
examples, the ionization cross sections of hydrogen and helium atoms by various
fully stripped ions.Comment: 46 pages, 8 figure
Molecular mechanism of BMP signal control by Twisted gastrulation
Twisted gastrulation (TWSG1) is an evolutionarily conserved secreted glycoprotein which controls signaling by Bone Morphogenetic Proteins (BMPs). TWSG1 binds BMPs and their antagonist Chordin to control BMP signaling during embryonic development, kidney regeneration and cancer. We report crystal structures of TWSG1 alone and in complex with a BMP ligand, Growth Differentiation Factor 5. TWSG1 is composed of two distinct, disulfide-rich domains. The TWSG1 N-terminal domain occupies the BMP type 1 receptor binding site on BMPs, whereas the C-terminal domain binds to a Chordin family member. We show that TWSG1 inhibits BMP function in cellular signaling assays and mouse colon organoids. This inhibitory function is abolished in a TWSG1 mutant that cannot bind BMPs. The same mutation in the Drosophila TWSG1 ortholog Tsg fails to mediate BMP gradient formation required for dorsal-ventral axis patterning of the early embryo. Our studies reveal the evolutionarily conserved mechanism of BMP signaling inhibition by TWSG1
Neurochemical Changes in the Mouse Hippocampus Underlying the Antidepressant Effect of Genetic Deletion of P2X7 Receptors.
Recent investigations have revealed that the genetic deletion of P2X7 receptors (P2rx7) results in an antidepressant phenotype in mice. However, the link between the deficiency of P2rx7 and changes in behavior has not yet been explored. In the present study, we studied the effect of genetic deletion of P2rx7 on neurochemical changes in the hippocampus that might underlie the antidepressant phenotype. P2X7 receptor deficient mice (P2rx7-/-) displayed decreased immobility in the tail suspension test (TST) and an attenuated anhedonia response in the sucrose preference test (SPT) following bacterial endotoxin (LPS) challenge. The attenuated anhedonia was reproduced through systemic treatments with P2rx7 antagonists. The activation of P2rx7 resulted in the concentration-dependent release of [3H]glutamate in P2rx7+/+ but not P2rx7-/- mice, and the NR2B subunit mRNA and protein was upregulated in the hippocampus of P2rx7-/- mice. The brain-derived neurotrophic factor (BDNF) expression was higher in saline but not LPS-treated P2rx7-/- mice; the P2rx7 antagonist Brilliant blue G elevated and the P2rx7 agonist benzoylbenzoyl ATP (BzATP) reduced BDNF level. This effect was dependent on the activation of NMDA and non-NMDA receptors but not on Group I metabotropic glutamate receptors (mGluR1,5). An increased 5-bromo-2-deoxyuridine (BrdU) incorporation was also observed in the dentate gyrus derived from P2rx7-/- mice. Basal level of 5-HT was increased, whereas the 5HIAA/5-HT ratio was lower in the hippocampus of P2rx7-/- mice, which accompanied the increased uptake of [3H]5-HT and an elevated number of [3H]citalopram binding sites. The LPS-induced elevation of 5-HT level was absent in P2rx7-/- mice. In conclusion there are several potential mechanisms for the antidepressant phenotype of P2rx7-/- mice, such as the absence of P2rx7-mediated glutamate release, elevated basal BDNF production, enhanced neurogenesis and increased 5-HT bioavailability in the hippocampus
A multistep process for the dispersal of a Y chromosomal lineage in the Mediterranean area
Tn this work we focus on a microsatellite-defined Y-chromosomal lineage (network 1.2) identified by us and reported in previous studies, whose geographic distribution and antiquity appear to be compatible with the Neolithic spread of farmers. Here, we set network 1.2 in the Y-chromosomal phylogenetic tree, date it with respect to other lineages associated with the same movements by other authors, examine its diversity by means of tri- and tetranucleotide loci and discuss the implications hi reconstructing the spread of this group of chromosomes in the Mediterranean area. Our results define a tripartite phylogeny wit-bin HG 9 (Rosser et al. 2000) with the deepest branching defined by alleles T (Haplogroup Eu 10) or G (Haplogroup Eu9) at M172 (Semino et al. 2000), and a subsequent branching within Eu9 defined by network 1.2. Population distributions of HG 9 and network 1.2 show that their occurrence in the surveyed area is not due to the spread of people from a single parental population but, rather, to a process punctuated by at least two phases. Our data identify the wide area of the Balkans, Aegean and Anatolia as the possible homeland harbouring the largest variation within network 1.2. The use of recently proposed tests based on the stepwise mutation model suggests that its spread was associated to a population expansion, xvith a high rate of male gene flow in the Turkish Greek area
Feasibility and effectiveness of offering a solution-focused follow-up to employees with psychological problems or muscle skeletal pain: a randomised controlled trial
BACKGROUND: Long-term sick leave has been of concern to politicians and decision-makers in Norway for several years. In the current study we assess the feasibility and effectiveness of offering a voluntary, solution-focused follow-up to sick-listed employees. METHODS: Employees on long-term sick leave due to psychological problems or muscle skeletal pain were randomly allocated to be offered a solution-focused follow-up (n = 122) or "treatment as usual" (n = 106). The intervention was integrated within 2 social security offices' regular follow-up. The intervention group was informed about the offer with letters, telephone calls and information meetings. Feasibility was measured by rate of uptake to the intervention, and effectiveness by number of days on sick leave. RESULTS: In general, few were reached with the different information elements. While the letter was sent to all, only 31% were reached by telephone and 15% attended the information meetings. Thirteen employees (11.5%) in the intervention group participated in the solution-focused follow-up. Intention to treat analysis showed no difference in mean length of sick leave between the intervention group (217 days) and the control group (189 days) (p = 0,101). CONCLUSION: Even if the information strategy might be improved, it is not likely that a voluntary solution-focused follow-up offered by the social security offices would result in measurable reduction in length of sick leave on a population level. However, the efficacy of a solution-focused follow-up for the persons reporting a need for this approach should be further investigated
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