4,499 research outputs found
A robust adaptive wavelet-based method for classification of meningioma histology images
Intra-class variability in the texture of samples is an important problem in the domain of histological image classification. This issue is inherent to the field due to the high complexity of histology image data. A technique that provides good results in one trial may fail in another when the test and training data are changed and therefore, the technique needs to be adapted for intra-class texture variation. In this paper, we present a novel wavelet based multiresolution analysis approach to meningioma subtype classification in response to the challenge of data variation.We analyze the stability of Adaptive Discriminant Wavelet Packet Transform (ADWPT) and present a solution to the issue of variation in the ADWPT decomposition when texture in data changes. A feature selection approach is proposed that provides high classification accuracy
Probing the band structure of quadri-layer graphene with magneto-phonon resonance
We show how the magneto-phonon resonance, particularly pronounced in sp2
carbon allotropes, can be used as a tool to probe the band structure of
multilayer graphene specimens. Even when electronic excitations cannot be
directly observed, their coupling to the E2g phonon leads to pronounced
oscillations of the phonon feature observed through Raman scattering
experiments with multiple periods and amplitudes detemined by the electronic
excitation spectrum. Such experiment and analysis have been performed up to 28T
on an exfoliated 4-layer graphene specimen deposited on SiO2, and the observed
oscillations correspond to the specific AB stacked 4-layer graphene electronic
excitation spectrum.Comment: 11 pages, 5 Fi
Few layer graphene on SiC, pyrolitic graphite and graphene: a Raman scattering study
The results of micro-Raman scattering measurements performed on three
different ``graphitic'' materials: micro-structured disks of highly oriented
pyrolytic graphite, graphene multi-layers thermally decomposed from carbon
terminated surface of 4H-SiC and an exfoliated graphene monolayer are
presented. Despite its multi-layer character, most parts of the surface of the
graphitized SiC substrates shows a single-component, Lorentzian shape, double
resonance Raman feature in striking similarity to the case of a single graphene
monolayer. Our observation suggests a very weak electronic coupling between
graphitic layers on the SiC surface, which therefore can be considered to be
graphene multi-layers with a simple (Dirac-like) band structure.Comment: 4 pages, 3 Figures Structure of the paper strongly modified, small
changes in Fig 2 and 3. Same interpretation and same result
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Subregional Hippocampal Thickness Abnormalities in Older Adults with a History of Heavy Cannabis Use.
Background and Aims: Legalization of cannabis (CB) for both medicinal and, in some states, recreational use, has given rise to increasing usage rates across the country. Of particular concern are indications that frequent CB use may be selectively harmful to the developing adolescent brain compared with adult-onset usage. However, the long-term effects of heavy, adolescent CB use on brain structure and cognitive performance in late-life remain unknown. A critical brain region is the hippocampus (HC), where there is a striking intersection between high concentrations of cannabinoid 1 (CB1) receptors and age-related pathology. Design: We investigated whether older adults (average age=66.6+7.2 years old) with a history of early life CB use show morphological differences in hippocampal subregions compared with older, nonusers. Methods: We performed high-resolution magnetic resonance imaging combined with computational techniques to assess cortical thickness of the medial temporal lobe, neuropsychological testing, and extensive drug use histories on 50 subjects (24 formerly heavy cannabis users [CB+ group] abstinent for an average of 28.7 years, 26 nonusers [CB- group]). We investigated group differences in hippocampal subregions, controlling for age, sex, and intelligence (as measured by the Wechsler Test of Adult Reading), years of education, and cigarette use. Results: The CB+ subjects exhibited thinner cortices in subfields cornu ammonis 1 [CA1; F(1,42)=9.96, p=0.0003], and CA2, 3, and the dentate gyrus [CA23DG; F(1,42)=23.17, p<0.0001], and in the entire HC averaged over all subregions [F(1,42)=8.49, p=0.006]. Conclusions: Negative effects of chronic adolescent CB use on hippocampal structure are maintained well into late life. Because hippocampal cortical loss underlies and exacerbates age-related cognitive decline, these findings have profound implications for aging adults with a history of early life usage. Clinical Trial Registration: ClinicalTrials.gov # NCT01874886
Changing with the time: New ventures’ quest for innovation
New ventures are often based on new ideas and innovation. For creating and improving the innovation new ventures can draw on internal and external resources, to which they often have limited access. Our study analyses how new ventures can improve their innovation search by entering collaborative workspaces, so-called co-working spaces. In our qualitative study, we use participative observation and analyze 8 cases of new ventures operating in a coworking-space. Key findings are that forms of innovation search differ with respect to the venture’s life cycle. The new ventures search focus alternates between internal and external search, depending on the current stage of the venture. In general, the co-location of ventures in collaborative workspaces offers rich opportunities for social interactions, information exchange, and collaboration which are especially important for early-stage ventures
Seamless Variability Management With the Virtual Platform
Customization is a general trend in software engineering, demanding systems
that support variable stakeholder requirements. Two opposing strategies are
commonly used to create variants: software clone & own and software
configuration with an integrated platform. Organizations often start with the
former, which is cheap, agile, and supports quick innovation, but does not
scale. The latter scales by establishing an integrated platform that shares
software assets between variants, but requires high up-front investments or
risky migration processes. So, could we have a method that allows an easy
transition or even combine the benefits of both strategies? We propose a method
and tool that supports a truly incremental development of variant-rich systems,
exploiting a spectrum between both opposing strategies. We design, formalize,
and prototype the variability-management framework virtual platform. It bridges
clone & own and platform-oriented development. Relying on
programming-language-independent conceptual structures representing software
assets, it offers operators for engineering and evolving a system, comprising:
traditional, asset-oriented operators and novel, feature-oriented operators for
incrementally adopting concepts of an integrated platform. The operators record
meta-data that is exploited by other operators to support the transition. Among
others, they eliminate expensive feature-location effort or the need to trace
clones. Our evaluation simulates the evolution of a real-world, clone-based
system, measuring its costs and benefits.Comment: 13 pages, 10 figures; accepted for publication at the 43rd
International Conference on Software Engineering (ICSE 2021), main technical
trac
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The Role of ICT in the Transformation of Government and Citizen Trust
We present an empirically tested conceptual model based on exit-voice theory to study the influence
of information and communications technology (ICT)-enabled transformation of government (IETG)
on citizen trust in government. We conceptualize and address the key factors affecting the influence
of transformation of government on citizen trust, including government performance and
transparency. Based on 313 survey responses randomly collected from citizens in Bahrain, the topranked
country in ICT adoption in the Gulf Cooperation Council (GCC) region, we test government
performance and transparency as mediators between transformation of government and citizen trust in
government. The resulting preliminary insights on the measurement and manifestation of citizen trust
in the context of IETG have multiple policy implications and extend our understanding of how IETG
can improve the government-citizen relationship and digital services adoption
Human cytomegalovirus plasmid-based amplicon vector system for gene therapy
We have constructed and evaluated the utility of a helper-dependent virus vector system that is derived from Human Cytomegalovirus (HCMV). This vector is based on the herpes simplex virus (HSV) amplicon system and contains the HCMV orthologs of the two cis-acting functions required for replication and packaging of HSV genomes, the complex HCMV viral DNA replication origin (oriLyt), and the cleavage packaging signal (the a sequence). The HCMV amplicon vector replicated independently and was packaged into infectious virions in the presence of helper virus. This vector is capable of delivering and expressing foreign genes in infected cells including progenitor cells such as human CD34+ cells. Packaged defective viral genomes were passaged serially in fibroblasts and could be detected at passage 3; however, the copy number appeared to diminish upon serial passage. The HCMV amplicon offers an alternative vector strategy useful for gene(s) delivery to cells of the hematopoietic lineage
Analysis of Soot Particle Movement in Diesel Engine under the Influence of Drag Force
The formation of soot is influenced by the composition of air entrainment and structure of hydrocarbon in the fuel. Soot will then form during combustion in a diesel engine. Some of the soot particles will be released from the engine through the exhaust nozzle and some will stick to the cylinder walls. The soot that sticks to the cylinder wall can affect the lifetime of the lubricant oil. Subsequently this will decrease the durability of the diesel engine. By understanding the movement of the soot particles, the effect to the engine can be decreased. Therefore, the initial position and last position of soot particle was recognized through this study. The data for the formation of soot particles in the diesel engine was obtained from previous investigation. The study of soot movement at 8° crankshaft angle under the influence of drag force with different radial, axial and angular settings were carried out using a MATLAB routine. The results showed that the movement of soot particle will change with different parameter settings. Besides that, comparison of the results of soot particle movement influenced by drag force and without drag force has been carried out. It was observed that drag force caused shorter soot particle movement path and moves them away from the cylinder wall
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