212 research outputs found
Fifty shades of grey hat: A socio-psychological analysis of conversations on hacking forums
There remains a lack of understanding as to what determines the path which a young person takes when they first engage with computers and hacking. This research sought to address that gap by exploring the conversations that take place on hacking forums and subreddits. Text in hacking related threads was collected from these sites over the summer period of 2018. Linguistic Inquiry and Word Count (LIWC) software was used to determine the linguistic characteristics of each forum/ subreddit. Thematic analysis was then conducted on a sub-set of text from each source. The results of the LIWC analysis indicated that there are variations in several psychologically relevant factors between these forums and subreddits, including the degree to which users used language that indicated they were being honest, confident, analytical and emotional. There were several results that were inconsistent with stereotypes of hackers, such as a relative absence of language indicating anger. The thematic analysis identified several themes relating to knowledge, skills acquisition, honesty legality and risk. Overall this research demonstrates that there exists an established online community of hackers, which are likely to be encountered by any young person who becomes interested in cybersecurity and hacking. These communities may potentially act as an important source of social support and social identity for their members. Understanding the dynamics of these communities may better help us steer people towards legitimate cybersecurity careers, where their passion and skills can be used for societal good
Recent advances in diffusion neuroimaging: applications in the developing preterm brain
Measures obtained from diffusion-weighted imaging provide objective indices of white matter development and injury in the developing preterm brain. To date, diffusion tensor imaging (DTI) has been used widely, highlighting differences in fractional anisotropy (FA) and mean diffusivity (MD) between preterm infants at term and healthy term controls; altered white matter development associated with a number of perinatal risk factors; and correlations between FA values in the white matter in the neonatal period and subsequent neurodevelopmental outcome. Recent developments, including neurite orientation dispersion and density imaging (NODDI) and fixel-based analysis (FBA), enable white matter microstructure to be assessed in detail. Constrained spherical deconvolution (CSD) enables multiple fibre populations in an imaging voxel to be resolved and allows delineation of fibres that traverse regions of fibre-crossings, such as the arcuate fasciculus and cerebellar-cortical pathways. This review summarises DTI findings in the preterm brain and discusses initial findings in this population using CSD, NODDI, and FBA
The effect of inter-granular constraints on the response of polycrystalline piezoelectric ceramics at the surface and in the bulk
Knowledge is power: An analysis of discussions on hacking forums
There remains a lack of understanding on the social factors that influence the behaviours and beliefs of people who have an interest in hacking. This research sought to address that gap by exploring the conversations that take place on hacking forums and subreddits. Text in hacking related threads was collected from these sites over a period of several months. Linguistic Inquiry and Word Count (LIWC) software was used to determine the linguistic characteristics of each forum/ subreddit. Thematic analysis was then conducted on a sub-set of text from each source. The results of the LIWC analysis indicated that there are variations in several psychologically relevant factors between these forums and subreddits, including the degree to which users used language that indicated they were being honest, confident, analytical and emotional. There were several results that were inconsistent with stereotypes of hackers, such as a relative absence of language indicating anger. The thematic analysis identified several themes relating to knowledge, skills acquisition, honesty legality and risk. Overall, this research demonstrates that there exists an established online community of hackers, which are likely to be encountered by any young person who becomes interested in cybersecurity and hacking. These communities may potentially act as an important source of social support and social identity for their members. Understanding the dynamics of these communities may better help us steer people towards legitimate cybersecurity careers, where their passion and skills can be used for societal good
Tailoring of unipolar strain in lead-free piezoelectrics using the ceramic/ceramic composite approach
The electric-field-induced strain response mechanism in a polycrystalline ceramic/ceramic composite of relaxor and ferroelectric materials has been studied using in situ high-energy x-ray diffraction. The addition of ferroelectric phase material in the relaxor matrix has produced a system where a small volume fraction behaves independently of the bulk under an applied electric field. Inter- and intra-grain models of the strain mechanism in the composite material consistent with the diffraction data have been proposed. The results show that such ceramic/ceramic composite microstructure has the potential for tailoring properties of future piezoelectric materials over a wider range than is possible in uniform compositions.open1
Diffusion magnetic resonance imaging assessment of regional white matter maturation in preterm neonates
PURPOSE: Diffusion magnetic resonance imaging (dMRI) studies report altered white matter (WM) development in preterm infants. Neurite orientation dispersion and density imaging (NODDI) metrics provide more realistic estimations of neurite architecture in vivo compared with standard diffusion tensor imaging (DTI) metrics. This study investigated microstructural maturation of WM in preterm neonates scanned between 25 and 45 weeks postmenstrual age (PMA) with normal neurodevelopmental outcomes at 2 years using DTI and NODDI metrics. METHODS: Thirty-one neonates (n = 17 male) with median (range) gestational age (GA) 32+1 weeks (24+2-36+4) underwent 3 T brain MRI at median (range) post menstrual age (PMA) 35+2 weeks (25+3-43+1). WM tracts (cingulum, fornix, corticospinal tract (CST), inferior longitudinal fasciculus (ILF), optic radiations) were delineated using constrained spherical deconvolution and probabilistic tractography in MRtrix3. DTI and NODDI metrics were extracted for the whole tract and cross-sections along each tract to assess regional development. RESULTS: PMA at scan positively correlated with fractional anisotropy (FA) in the CST, fornix and optic radiations and neurite density index (NDI) in the cingulum, CST and fornix and negatively correlated with mean diffusivity (MD) in all tracts. A multilinear regression model demonstrated PMA at scan influenced all diffusion measures, GA and GAxPMA at scan influenced FA, MD and NDI and gender affected NDI. Cross-sectional analyses revealed asynchronous WM maturation within and between WM tracts.). CONCLUSION: We describe normal WM maturation in preterm neonates with normal neurodevelopmental outcomes. NODDI can enhance our understanding of WM maturation compared with standard DTI metrics alone
Lifshitz-type Quantum Field Theories in Particle Physics
This introduction to Lifshitz-type field theories reviews some of its aspects
in Particle Physics. Attractive features of these models are described with
different examples, as the improvement of graphs convergence, the introduction
of new renormalizable interactions, dynamical mass generation, asymptotic
freedom, and other features related to more specific models. On the other hand,
problems with the expected emergence of Lorentz symmetry in the IR are
discussed, related to the different effective light cones seen by different
particles when they interact.Comment: 26 pages, comments and references adde
A sample cell for in situ electric-field-dependent structural characterization and macroscopic strain measurements
When studying electro-mechanical materials, observing the structural changes during the actuation process is necessary for gaining a complete picture of the structure-property relationship as certain mechanisms may be meta-stable during actuation. In situ diffraction methods offer a powerful and direct means of quantifying the structural contributions to the macroscopic strain of these materials. Here, a sample cell is demonstrated capable of measuring the structural variations of electro-mechanical materials under applied electric potentials up to 10?kV. The cell is designed for use with X-ray scattering techniques in reflection geometry, while simultaneously collecting macroscopic strain data using a linear displacement sensor. The results show that the macroscopic strain measured using the cell can be directly correlated with the microscopic response of the material obtained from diffraction data. The capabilities of the cell have been successfully demonstrated at the Powder Diffraction beamline of the Australian Synchrotron and the potential implementation of this cell with laboratory X-ray diffraction instrumentation is also discussed.A sample cell for in situ electric-field-dependent structural characterization and macroscopic strain measurements is demonstrated. The results show that the macroscopic strain measured using the cell can be directly correlated with the microscopic response of the material obtained from diffraction data
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