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The inclusion of thin lossy, material layers, such as carbon based composites, is essential for many practical applications modeling the propagation of electromagnetic energy through composite structures such as those found in vehicles and electronic equipment enclosures. Many existing schemes suffer problems of late time instability, inaccuracy at low frequency, and/or large computational costs. This work presents a novel technique for the modeling of thin-layer lossy materials in FDTD schemes which overcomes the instability problem at low computational cost. For this, a 1D-subgrid is used for the spatial discretization of the thin layer material. To overcome the additional time-step constraint posed by the reduction in the spatial cell size, a Crank-Nicolson time-integration scheme is used locally in the subgridded zone, and hybridized with the usual 3D Yee-FDTD method, which is used for the rest of the computational domain. Several numerical experiments demonstrating the accuracy of this approach are shown and discussed. Results comparing the proposed technique with classical alternatives based on impedance boundary condition approaches are also presented. The new technique is shown to have better accuracy at low frequencies, and late time stability than existing techniques with low computational cost.

This thesis investigates singularimetry in both optical and matter wave fields. The utility of optical singularities for performing phase measurements was demonstrated using a three–beam interferometer. Three–wave interference was used to generate a uniform lattice of optical vortices, which was distorted by the presence of an object inserted into one arm of the interferometer. Using theoretical ideas from singular wave optics, a proportionality between the transverse displacement of the vortices and the phase shift in the object wave was derived and experimentally tested. Tracking the vortices permitted the phase of the object to be reconstructed. We demonstrated the method experimentally using a simple lens and a more complex object, namely the wing of a common house fly. Since the technique is implemented in real space, it is capable of reconstructing the phase locally. By studying the extreme opposite of nodal singularities, an alternative phase retrieval technique was designed and numerically tested, which utilizes the natural intensity singularities of caustics. Using catastrophe theory, we showed that, given the formation of a fold caustic in the wave field, the functional form of the wave’s phase may be expressed as a truncated Taylor series. We then outlined how all expansion coefficients in the series may be determined by quantifying unfolding of the caustic through focus, thus framing this otherwise ill–posed inverse problem into a well–posed one. The method was then successfully implemented on simulated data. Possibilities of extending the technique to higher order catastrophes are also discussed. The relationship between caustics and vortices in matter waves was also investigated. By inducing aberrations in the magnetic lenses of a conventional transmission electron microscope, it is shown that diffraction catastrophes may be created in the electron beam. As a consequence of the duality of caustics and vortices—a central theme to the thesis—electron vortices were created in the electron beam in the vicinity of the caustics. To measure and explore the quantized anomalous Gouy shift of focused astigmatic electron waves, caustics were again generated by inducing aberrations in the lenses and the Gouy phase shift determined by phase retrieval. Multiple theoretical descriptions of the Gouy phase anomaly are presented and discussed. It is shown that these various interpretations may be unified into a single theoretical framework. Lastly, we investigated caustics in the context of order–parameter manifolds. We show that caustic surfaces also appear when a real or complex field is mapped to its order–parameter manifold. We exemplify these structures in the context of spin–1/2 fields, where the order– parameter manifold is the Bloch sphere. These generic structures are a manifestation of catastrophe theory and are stable with respect to perturbations. The corresponding field configurations are also stable and represent a new type of topological defect, which we call order–parameter catastrophe defects. Equations governing the conditions for the existence and unfolding of the defects are derived.

Obtaining the optimum surface finish is one of the key factors in machining operations. For this purpose, engineers apply a set of machining parameters to obtain the desired surface quality. On the other hand, tool faces wear during machining operation that itself affects the surface quality of machined surface. Therefore, tool wear and surface finish of machined workpiece should be related to each other. In this research, we employ fractal analysis in order to investigate the correlation between variations of complex structure of machined surface and tool wear in turning operation. In fact, we changed the machining parameters between different experiments and investigated how the machined surface is correlated with the tool wear. Based on the obtained results, we can see the correlation between the complexity of machined surface and tool wear by increasing the depth of cut, spindle speed and feed rate in different experiments. The method of analysis employed in this research can be widely applied to other machining operations in order to find the correlation between the surface quality of machined surface and tool wear.

The referral of patients for open heart surgery, presenting with a history of heparin hypersensitivity instigated a multidisciplinary effort to find an alternative anticoagulant to heparin. The various options mentioned in the literature call for changes in the routine practice of open heart surgery on cardiopulmonary bypass. These changes involve mostly the perfusion setup and conduct on bypass and to a lesser extent the anesthetic and surgical practice. Nevertheless, the different professions involved in the cardiac surgical firm discussed the proposed changes in a multidisciplinary effort. A new protocol was drafted, endorsed, and executed. The authors highlight these changes and their successful use in the subsequent case study.

Describable visual facial attributes are now commonplace in human biometrics and affective computing, with existing algorithms even reaching a sufficient point of maturity for placement into commercial products. These algorithms model objective facets of facial appearance, such as hair and eye color, expression, and aspects of the geometry of the face. A natural extension, which has not been studied to any great extent thus far, is the ability to model subjective attributes that are assigned to a face based purely on visual judgements. For instance, with just a glance, our first impression of a face may lead us to believe that a person is smart, worthy of our trust, and perhaps even our admiration - regardless of the underlying truth behind such attributes. Psychologists believe that these judgements are based on a variety of factors such as emotional states, personality traits, and other physiognomic cues. But work in this direction leads to an interesting question: how do we create models for problems where there is no ground truth, only measurable behavior? In this paper, we introduce a new convolutional neural network-based regression framework that allows us to train predictive models of crowd behavior for social attribute assignment. Over images from the AFLW face database, these models demonstrate strong correlations with human crowd ratings.

Idealised tropical and extratropical cyclones, and a historic medicane are simulated using the Coupled-Ocean-Atmosphere-Wave-Sediment Transport Modeling System. This manuscript examines the sensitivity of: surface wind and waves to ocean temperature for tropical cyclones (TCs); precipitation to atmospheric temperature for extra-tropical cyclones; wind, waves and precipitation to simultaneous increases in atmospheric and oceanic temperature for the medicane. More intense and larger TCs, with higher waves, form when ocean temperature is increased. The maximum significant wave height increases more than the maximum wind speed for TCs up to hurricane-force wind. Above hurricane-force wind this relationship is reversed. This is explained by the wind drag coefficient dependence on wind speed. The relative increase in the footprint of high waves is considerably greater than the increase in the maximum wave height as ocean temperature is increased. This suggests a future warmer ocean will result in a large increase in the surface area of damaging waves generated by TCs. For the extratropical cyclones the footprint of extreme precipitation (total surface area where accumulated precipitation exceeds high thresholds) and the accumulation in different sized catchment areas is examined. The footprint of extreme precipitation grows considerably with temperature. When the catchment areas are ranked in order of total precipitation, super Clausius-Clapeyron behaviour of the 99th percentile is found for all the catchment sizes. This surprising result for larger catchment areas is due to spatially concentrated changes in the extreme precipitation. A more intense, significantly larger medicane generally developed when temperatures were increased. The greater area of high winds led to increases in both the maximum significant wave height and the footprint of high waves. The mean and extreme precipitation increased with temperature slightly and substantial faster than Clausius-Clapeyron scaling respectively, this was accompanied by a larger but less fragmented footprint of extreme precipitation. Open Access

Purpose: To establish radiopharmaceutical standards in a Nuclear Medicine Department in terms of radiochemical purity. Radionuclide standards were assessed in terms of radionuclide and chemical purity as well as pH as part of a quality control (QC) programme., Objectives: An accurate and complete literature search was conducted identifying the needs, specific tests and resources required for the QC programme. A QC protocol was implemented; data collected and findings documented determining current standards and the impact of implementation of a QC programme on work practice., Methodology: Quantitative data was collected by means of a prospective, non-experimental research design. QC of the radionuclide was performed on all the accessible population, while random sampling was utilized to select a sample to determine the radiochemical purity of radiopharmaceuticals included in the study., Results: Findings indicate that the radionuclide always met the required standards, which were in accordance with the European Pharmacopeia. The radionuclide purity was up to standards since 99Mo never exceeded more than 0.1% of the total 99mTc activity. The test for chemical purity showed that no samples contained Al3+ and the pH values measured all fell within the accepted range of 4-8. The results however revealed that substandard radiopharmaceuticals were frequently prepared, since the radiochemical purity of several (60.6%) samples fell below the lower limit of acceptance., Conclusion: The findings indicate that substandard radiopharmaceuticals were a result of preparation error. The results were presented to all staff and work practices are currently being altered to improve radiopharmaceutical standards. The implementation of a full QA programme for radiopharmaceuticals is also in prospect., peer-reviewed

For many problems in computer vision, human learners are considerably better than machines. Humans possess highly accurate internal recognition and learning mechanisms that are not yet understood, and they frequently have access to more extensive training data through a lifetime of unbiased experience with the visual world. We propose to use visual psychophysics to directly leverage the abilities of human subjects to build better machine learning systems. First, we use an advanced online psychometric testing platform to make new kinds of annotation data available for learning. Second, we develop a technique for harnessing these new kinds of information—“perceptual annotations”—for support vector machines. A key intuition for this approach is that while it may remain infeasible to dramatically increase the amount of data and high-quality labels available for the training of a given system, measuring the exemplar-by-exemplar difficulty and pattern of errors of human annotators can provide important information for regularizing the solution of the system at hand. A case study for the problem face detection demonstrates that this approach yields state-of-the-art results on the challenging FDDB data set.

This article presents a boy with bilateral renal artery stenosis who presented with severe hypertension and haemorrhagic stroke. The diagnostic workup along with a complication of eventual surgical intervention are demonstrated., peer-reviewed

Nicotine, the major specific alkaloid in tobacco smoke, exhibits widespread pharmacological effects and may contribute to deterioration in behaviour. The present study thus examined the effects of its chronic administration on some cognitive and mood associated behaviours. Adult rats weighing between 150 and 200g were randomly divided into 4 groups each of 5 females and 5 males. Three groups were administered graded doses of nicotine at 0.25, 2 and 4mg/kg body weight via subcutaneous injections. One group served as control and received normal saline (vehicle for nicotine). Behavioural tests were performed using the Y-maze, elevated-plus maze (EPM) and tail suspension tests (TST) at various time points. Nicotine produced no significant effect in spontaneous alternation on Y-maze, nor on six parameters scored on EPM (open arm entries, time spent in open arms, time per open arm entries, open/closed arm quotient, closed arm entries, and total arm entries), and also no significant effect on immobility time in TST. This lack of effects was observed to be independent of sex and dose administered. The study shows that nicotine does not produce long-term changes in some cognitive and mood associated behaviours, thus suggesting it could be well tolerated even following chronic administration.

We provide a unified description of the Gouy phase anomaly, highlighting the pivotal role of local fluctuations in transverse momentum and quantal phase changes associated with electron trajectories that touch caustics. Using arguments based on wave optics, at the interface between classical and quantum mechanics, we derive the magnitude of the quantized Gouy phase changes for scalar waves. Our analysis unifies disparate descriptions of the Gouy anomaly within a single theoretical framework. In particular, we find that the phase anomaly connects Maslov indices, quantal Berry phases, Heisenberg momentum fluctuations, and confinement-induced L\'evy-Leblond phase shifts.

Singularities in wave fields, such as phase vortices, are of substantial interest for light optics, matter waves and x-ray optics. New theoretical insights [1] and cutting edge nanofabrication techniques have recently created a wide variety of electron vortex beams [2, 3] for the transmission electron microscope (TEM), which can provide spectroscopic information pertaining to the magnetic properties of nanoscale specimens [2]. The rich diffraction physics of singular optics is vast and many concepts can be directly translated to electron microscopy. Interesting physics has been discovered by highlighting differences between electron and optical vortex beams, such as a remarkable interplay between Zeeman coupling, Landau levels and Gouy phases in the TEM [4] or the Faraday effect for electron vortex beams propagating in a magnetic field, which interestingly occurs in vacuum [5].

We measure the Gouy phase anomaly for matter waves using in-line holography to retrieve the full complex field of an astigmatic electron wave function. Sequential phase shifts of \ensuremath{\pi}/2 rad are observed for electron trajectories along the optic axis that pass through each line-focus caustic of subnanometer transverse width. Our observations demonstrate that anomalous phase shifts of matter waves in the vicinity of caustics can be robustly measured using phase retrieval, extending the current scope of singular electron optics.

An aberration corrected electron microscope is used to create electron diffraction catastrophes, containing arrays of intensity zeros threading vortex cores. Vortices are ascribed to these arrays using catastrophe theory, scalar diffraction integrals, and experimentally retrieved phase maps. From measured wave function phases, obtained using focal-series phase retrieval, the orbital angular momentum density is mapped for highly astigmatic electron probes. We observe vortex rings and topological reconnections of nodal lines by tracking the vortex cores using the retrieved phases.

We have developed a differential form of singularimetry, which utilizes phase vortices or intensity gradient singularities as topological fiducial markers in a structured illumination context. This approach analytically measures phase gradients imparted by refracting specimens, yielding quantitative information that is both local and deterministic. We have quantified our phase gradient experiments to demonstrate that lattices of wave field singularities can be used to detect subtle phase gradients imparted by a spherical specimen and fiber optic cylinders.

The leading cause of morbidity and mortality during pregnancy and the puerperium is venous thromboembolism. Though uncommon, the risk is five times higher in a pregnant woman than in a non-pregnant woman of similar age.1,2 In pregnancy, all three underlying factors for venous thrombosis are present: hypercoagulability, venous stasis and vascular damage (Virchow's triad). Of these, the most constant predisposing factor is increasing venous stasis due to the pressure of the gravid uterus on the pelvic vasculature. In addition the presence of a thrombophilia, (congenital or acquired) will increase this risk substantially. During pregnancy hypercoagulability is a physiological preparation for the haemostatic challenge of delivery. There are increases in procoagulant factors, such as von Willebrand factor, factor VIII, factor V, and fibrinogen together with an acquired resistance to activated protein C and a reduction in protein S. Increases in plasminogen activator inhibitors impair fibrinolysis. The third factor of this triad, vascular damage, is a possible complication of trophoblastic invasion of the uterine spiral arterioles or of delivery., peer-reviewed

A 74-year-old man on warfarin for aortic valve replacement presented with recurrent episodes of melaena. An initial oesophagogastroduodenoscopy (OGD) was normal, as were red cell scanning and colonoscopy. It was a third OGD that revealed the cause of the melaena—a vascular lesion in the duodenum, at the junction between D1 and D2. An extragastric Dieulafoy's lesion was diagnosed, and the lesion was injected with epinephrine and tattooed. Over the following months, episodes of bleeding recurred despite further attempts at injection. Percutaneous radiologically assisted embolisation of the gastroduodenal artery, and eventually duodenotomy and oversuturing of the lesion were performed to no avail. The patient has undergone over 10 endoscopies, and has received over 70 units of packed red cells to date, since his initial presentation 6 years ago. Attempts to stop the bleeding permanently have been difficult, highlighting the complexity of managing such a lesion.

Existing models of facial personality trait judgments control a large number of likely sources of variance for real-world trait judgments. ! Our data set includes reliable trait ratings on images with these sources of variance included. ! It is possible to train a computer vision algorithm on trait-rated real-world images that approximates human trait judgments. ! This points to future avenues for empirically studying underexplored factors that contribute to personality judgments. Conclusions Question and Approach

Phase retrieval is widely used in phase contrast microscopy. Here we present an autofocus algorithm that allows the phase of the exit wave function, from a single-material object, to be reconstructed at medium resolution from a single phase contrast image without any a priori knowledge of the imaging system or object. The algorithm is demonstrated on coherent out-of-focus electron micrographs of 30 nm latex sphere calibration standards, giving