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Searches for new physics phenomena with jet final states in the ATLAS detector

Collimated sprays of paticle, known as jets,are abundantly produced in high-energy proton-proton (pp) collisions, and are predicted by many theories of physics beyond the Standard Model. This thesis reports first on the calibration of jets with focus on the data-driven in situ calibration. Two searches for new physics phenomena in events with jets in the final state are then presented. The analyse

Photovoltaic nanowires affect human lung cell proliferation under illumination conditions

Using light to interact with cells is a promising way to steer cell behavior with minimal perturbation. Besides optogenetics, photovoltaic nanostructures such as nanowires can be used to interact with cells using light as a switch. Photovoltaic nanowires have, for instance, been used to stimulate neurons. However, the effects of the photovoltaic activity on cells are still poorly understood and ch

Parenchymal Texture Analysis in Digital Breast Tomosynthesis for Breast Cancer Risk Estimation. A Preliminary Study

Rationale and Objectives: Studies have demonstrated a relationship between mammographic parenchymal texture and breast cancer risk. Although promising, texture analysis in mammograms is limited by tissue superposition. Digital breast tomosynthesis (DBT) is a novel tomographic x-ray breast imaging modality that alleviates the effect of tissue superposition, offering superior parenchymal texture vis

Generation and evaluation of physically inspired synthetic mammograms

A software breast phantom, based upon a breast tissue model derived from physical properties of breast anatomy, has been developed for mammography simulation. Synthetic mammograms, obtained by applying a breast compression model and an x-ray acquisition model to the software breast phantom, were compared by quantitative and qualitative means with real mammograms at different scales. Good agreement

Systematic variation in North American tree species abundance distributions along macroecological climatic gradients

Aim: The species abundance distribution (SAD) is a fundamental pattern in macroecology. Understanding how SADs vary spatially, and identifying the variables that drive any change, is important from a theoretical perspective because it enables greater understanding of the factors that underpin the relative abundance of species. However, precise knowledge on how the form of SADs varies across large

On the validity of different methods to estimate breakup frequency from single drop experiments

Single drop breakup visualizations are the golden standard for experimentally measuring breakup frequency, g, in turbulent flows. There is a growing demand for empirically obtained breakup frequencies, for population balance equation (PBE) based predictive modelling and for comparing to theoretical suggestions. However, five different methods to estimate g from a breakup visualization can be found

Description and Characterization of a Novel Method for Partial Volume Simulation in Software Breast Phantoms

A modification to our previous simulation of breast anatomy is proposed to improve the quality of simulated x-ray projections images. The image quality is affected by the voxel size of the simulation. Large voxels can cause notable spatial quantization artifacts; small voxels extend the generation time and increase the memory requirements. An improvement in image quality is achievable without redu

Estimation of scattered radiation in digital breast tomosynthesis

Digital breast tomosynthesis (DBT) is a promising technique to overcome the tissue superposition limitations found in planar 2D x-ray mammography. However, as most DBT systems do not employ an anti-scatter grid, the levels of scattered radiation recorded within the image receptor are significantly higher than that observed in planar 2D x-ray mammography. Knowledge of this field is necessary as par

A statistically defined anthropomorphic software breast phantom

Purpose: Digital anthropomorphic breast phantoms have emerged in the past decade because of recent advances in 3D breast x-ray imaging techniques. Computer phantoms in the literature have incorporated power-law noise to represent glandular tissue and branching structures to represent linear components such as ducts. When power-law noise is added to those phantoms in one piece, the simulated fibrog

Analysis of parenchymal texture with digital breast tomosynthesis : Comparison with digital mammography and implications for cancer risk assessment

Purpose:To correlate the parenchymal texture features at digital breast tomosynthesis(DBT)and digital mammography with breast percent density(PD), an established breast cancer risk factor, in a screening population of women. Materials and Methods: This HIPAA-compliant study was approved by the institutional review board. Bilateral DBT images and digital mammograms from 71 women (mean age, 54 years

Calculation of the properties of digital mammograms using a computer simulation

A Mote Carlo computer model of mammography has been developed to study and optimise the performance of digital mammographic systems. The program uses high-resolution voxel phantoms to model the breast, which simulate the adipose and fibroglandular tissues, Cooper's ligaments, ducts and skin in three dimensions. The model calculates the dose to each tissue, and also the quantities such as energy im

Breast dosimetry using high-resolution voxel phantoms

A computer model of X-ray mammography has been developed, which uses quasi-realistic high-resolution voxel phantoms to simulate the breast. The phantoms have 400 μm voxels and simulate the three-dimensional distributions of adipose and fibroglandular tissues, Cooper's ligaments, ducts and skin and allow the estimation of dose to individual tissues. Calculations of the incident air kerma to mean gl

Aliasing effects in digital images of line-pair phantoms

Line-pair phantoms are commonly used for evaluating screen-film systems. When imaged digitally, aliasing effects give rise to additional periodic patterns. This paper examines one such effect that medical physicists are likely to encounter, and which can be used as an indicator of super-resolution.

Fossil Fuels Subsidies in the EU: EU State Aid Rules as Control and Phase out Tools - Opportunities and Estimates

The paper aims to identify and analyse potential legal avenues for phasing out fossil fuels in the European Union using EU State aid rules. Our analysis of the EU’s legal framework reveals that the EU State aid rules would allow the European Commission to effectively target and monitor fossil fuel subsidies. In particular, the requirements for notification, examination, transparency, reporting, an