Ministry of Defence

The risk of posttraumatic stress disorder (PTSD) following trauma is heritable, but robust common variants have yet to be identified. In a multi-ethnic cohort including over 30,000 PTSD cases and 170,000 controls we conduct a genome-wide association study of PTSD. We demonstrate SNP-based heritability estimates of 5-20%, varying by sex. Three genome-wide significant loci are identified, 2 in European and 1 in African-ancestry analyses. Analyses stratified by sex implicate 3 additional loci in men. Along with other novel genes and non-coding RNAs, a Parkinson's disease gene involved in dopamine regulation, PARK2, is associated with PTSD. Finally, we demonstrate that polygenic risk for PTSD is significantly predictive of re-experiencing symptoms in the Million Veteran Program dataset, although specific loci did not replicate. These results demonstrate the role of genetic variation in the biology of risk for PTSD and highlight the necessity of conducting sex-stratified analyses and expanding GWAS beyond European ancestry populations.

The combination of frequency-modulated continuous-wave (FMCW) technology and synthetic aperture radar (SAR) techniques leads to lightweight cost-effective imaging sensors of high resolution. One limiting factor to the use of FMCW sensors is the well-known presence of nonlinearities in the transmitted signal. This results in contrast- and range-resolution degradation, particularly when the system is intended for high-resolution long-range applications, as it is the case for SAR. This paper presents a novel processing solution, which solves the nonlinearity problem for the whole range profile. Additionally, the conventional stop-and-go approximation used in pulse-radar algorithms is not valid in FMCW SAR applications under certain circumstances. Therefore, the motion within the sweep needs to be taken into account. Analytical development of the FMCW SAR signal model, starting from the deramped signal and without using the stop-and-go approximation, is presented in this paper. The model is then applied to stripmap, spotlight, and single-transmitter/multiple-receiver digital-beamforming SAR operational mode. The proposed algorithms are verified by processing real FMCW SAR data collected with the demonstrator system built at the Delft University of Technology.

This paper presents a theoretical and empirical analysis of Expected Sarsa, a variation on Sarsa, the classic on-policy temporal-difference method for model-free reinforcement learning. Expected Sarsa exploits knowledge about stochasticity in the behavior policy to perform updates with lower variance. Doing so allows for higher learning rates and thus faster learning. In deterministic environments, Expected Sarsas updates have zero variance, enabling a learning rate of 1. We prove that Expected Sarsa converges under the same conditions as Sarsa and formulate specific hypotheses about when Expected Sarsa will outperform Sarsa and Q-learning. Experiments in multiple domains confirm these hypotheses and demonstrate that Expected Sarsa has significant advantages over these more commonly used methods.

We present an overview of our recent progress and the current state-of-the-art techniques of color image fusion for night vision applications. Inspired by previously developed color opponent fusing schemes, we initially developed a simple pixel-based false color-mapping scheme that yielded fused false color images with large color contrast and preserved the identity of the input signals. This method has been successfully deployed in different areas of research. However, since this color mapping did not produce realistic colors, we continued to develop a statistical color-mapping procedure that would transfer the color distribution of a given example image to a multiband nighttime image. This procedure yields a realistic color rendering. However, it is computationally expensive and achieves no color constancy since the mapping depends on the relative amounts of the different materials in the scene. By applying the statistical mapping approach in a color look-up-table framework, we finally achieved both color constancy and computational simplicity. This sample-based color transfer method is specific for different types of materials in a scene and can be easily adapted for the intended operating theatre and the task at hand. The method can be implemented as a look-up-table transform and is highly suitable for real-time implementations.

BACKGROUND: Self-reported values of height and weight are used increasingly despite warnings that these data-and derived body mass index (BMI) values-might be biased. The present study investigates whether differences between self-reported and measured values are the same for populations from different regions, and the influences of gender and age. METHODS: Differences between self-reported and measured weights, heights and resulting BMIs are compared for representative samples of the adult population of Italy, the Netherlands and North America. RESULTS: We observed that weight is under-reported (1.1 ± 2.6 kg for females and 0.4 ± 3.1 kg for males) and height over-reported (1.1 ± 2.2 cm for females and 1.7 ± 2.1 cm for males), in accordance with the literature. This leads to an overall underestimation of BMI values (0.7 ± 1.2 kg/m(2) or 2.8% for females and 0.6 ± 1.1 kg/m(2) or 2.3% for males). When BMI values are assigned to four categories (from 'underweight' to 'obesity'), 11.2% of the females and 12.0% of the males are categorized too low when self-reported weights and heights are used, with an extreme of 17.2% for Italian females. Older people tend to relatively over-report height and under-report weight, but the magnitude differs between countries and gender. CONCLUSION: We conclude that, apart from a general overestimation of height and underestimation of weight resulting in an underestimation of BMI, substantial differences are observed between countries, between females and males and between age groups.

In exposed hearts of anesthetized dogs with total A-V block, a sudden increase or decrease in heart rate changes the duration of refractoriness immediately. A steady state is established only after a few hundred beats. The time course of shortening of the refractory period caused by an increase in driving rate ("on" effect) has the following characteristics. The first beat shortens the refractory period, as determined from strength-interval curves, about 30% of the total shortening; the second beat shortens it 10% more. After the second beat, the rate of change in the duration of the refractory period suddenly becomes slower. Alternation of the refractory period begins with a slightly prolonged refractory period of the third beat and then diminishes rapidly in about the following 10 beats. These changes are in phase throughout the ventricular myocardium. Following sudden transition to a slower rhythm, the time course of lengthening of the refractory period ("off" effect) is opposite to the "on" effect: the alternation that occurs is less marked. Changes in the duration of the functional refractory period near the stimulus site are parallel to those in the threshold curves. These results demonstrate a long persistence of the effect on myocardial refractoriness of a previous cardiac frequency.

We present a novel algorithm for image fusion from irregularly sampled data. The method is based on the framework of normalized convolution (NC), in which the local signal is approximated through a projection onto a subspace. The use of polynomial basis functions in this paper makes NC equivalent to a local Taylor series expansion. Unlike the traditional framework, however, the window function of adaptive NC is adapted to local linear structures. This leads to more samples of the same modality being gathered for the analysis, which in turn improves signal-to-noise ratio and reduces diffusion across discontinuities. A robust signal certainty is also adapted to the sample intensities to minimize the influence of outliers. Excellent fusion capability of adaptive NC is demonstrated through an application of super-resolution image reconstruction.

Stereo vision is an attractive passive sensing technique for obtaining three-dimensional (3-D) measurements. Recent hardware advances have given rise to a new class of real-time dense disparity estimation algorithms. This paper examines their suitability for intelligent vehicle (IV) applications. In order to gain a better understanding of the performance and the computational-cost tradeoff, the authors created a framework of real-time implementations. This consists of different methodical components based on single instruction multiple data (SIMD) techniques. Furthermore, the resulting algorithmic variations are compared with other publicly available algorithms. The authors argue that existing publicly available stereo data sets are not very suitable for the IV domain. Therefore, the authors' evaluation of stereo algorithms is based on novel realistically looking simulated data as well as real data from complex urban traffic scenes. In order to facilitate future benchmarks, all data used in this paper is made publicly available. The results from this study reveal that there is a considerable influence of scene conditions on the performance of all tested algorithms. Approaches that aim for (global) search optimization are more affected by this than other approaches. The best overall performance is achieved by the proposed multiple-window algorithm, which uses local matching and a left-right check for a robust error rejection. Timing results show that the simplest of the proposed SIMD variants are more than twice as fast than the most complex one. Nevertheless, the latter still achieves real-time processing speeds, while their average accuracy is at least equal to that of publicly available non-SIMD algorithms

Post-traumatic stress disorder (PTSD) genetics are characterized by lower discoverability than most other psychiatric disorders. The contribution to biological understanding from previous genetic studies has thus been limited. We performed a multi-ancestry meta-analysis of genome-wide association studies across 1,222,882 individuals of European ancestry (137,136 cases) and 58,051 admixed individuals with African and Native American ancestry (13,624 cases). We identified 95 genome-wide significant loci (80 new). Convergent multi-omic approaches identified 43 potential causal genes, broadly classified as neurotransmitter and ion channel synaptic modulators (for example, GRIA1, GRM8 and CACNA1E), developmental, axon guidance and transcription factors (for example, FOXP2, EFNA5 and DCC), synaptic structure and function genes (for example, PCLO, NCAM1 and PDE4B) and endocrine or immune regulators (for example, ESR1, TRAF3 and TANK). Additional top genes influence stress, immune, fear and threat-related processes, previously hypothesized to underlie PTSD neurobiology. These findings strengthen our understanding of neurobiological systems relevant to PTSD pathophysiology, while also opening new areas for investigation.

This textbook presents in a unified manner the fundamentals of both continuous and discrete versions of the Fourier and Laplace transforms. These transforms play an important role in the analysis of all kinds of physical phenomena. As a link between the various applications of these transforms the authors use the theory of signals and systems, as well as the theory of ordinary and partial differential equations. The book is divided into four major parts: periodic functions and Fourier series, non-periodic functions and the Fourier integral, switched-on signals and the Laplace transform, and finally the discrete versions of these transforms, in particular the Discrete Fourier Transform together with its fast implementation, and the z-transform. This textbook is designed for self-study. It includes many worked examples, together with more than 120 exercises, and will be of great value to undergraduates and graduate students in applied mathematics, electrical engineering, physics and computer science.

BACKGROUND: Circulatory collapse is a leading cause of mortality among traumatic major exsanguination and in ruptured aortic aneurysm patients. Approximately 40% of patients die before hemorrhage control is achieved. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an adjunct designed to sustain the circulation until definitive surgical or endovascular repair. A systematic review was conducted for the current clinical use of REBOA in patients with hemodynamic instability and to discuss its potential role in improving prehospital and in-hospital outcome. METHODS: Systematic review and meta-analysis (1900-2017) using MEDLINE, Cochrane, EMBASE, Web of Science and Central and Emcare using the keywords "aortic balloon occlusion", "aortic balloon tamponade", "REBOA", and "Resuscitative Endovascular Balloon Occlusion" in combination with hemorrhage control, hemorrhage, resuscitation, shock, ruptured abdominal or thoracic aorta, endovascular repair, and open repair. Original published studies on human subjects were considered. RESULTS: A total of 490 studies were identified; 89 met criteria for inclusion. Of the 1436 patients, overall reported mortality was 49.2% (613/1246) with significant differences (p < 0.001) between clinical indications. Hemodynamic shock was evident in 79.3%, values between clinical indications showed significant difference (p < 0.001). REBOA was favored as treatment in trauma patients in terms of mortality. Pooled analysis demonstrated an increase in mean systolic pressure by almost 50 mmHg following REBOA use. CONCLUSION: REBOA has been used in trauma patients and ruptured aortic aneurysm patients with improvement of hemodynamic parameters and outcomes for several decades. Formal, prospective study is warranted to clarify the role of this adjunct in all hemodynamic unstable patients.

BACKGROUND: Virtual reality exposure therapy (VRET) and augmented reality exposure therapy (ARET) are digitally assisted psychotherapies that potentially enhance posttraumatic stress disorder (PTSD) treatment by increasing a patient's sense of presence during exposure therapy. This study aimed to systematically review current evidence regarding the efficacy of VRET and ARET as PTSD treatment. METHODS: A systematic electronic database search, a systematic quality assessment and two meta-analyses were conducted in accordance with PRISMA guidelines. RESULTS: Eleven studies on the efficacy of VRET for PTSD (n = 438) were found, but no studies on the efficacy of ARET. The majority of VRET studies were of a low quality and had heterogeneous results. Meta-analyses showed VRET outperformed waitlist control (standardized mean difference -0.64 (95% CI -1.05 to -0.22)) while no significant difference was found between VRET and active treatment conditions (standardized mean difference -0.25 (95% CI -0.77 to 0.27)). CONCLUSION: VRET was superior to waitlist control groups and as effective as other psychotherapies. However, the results showed considerable heterogeneity due to the low number of studies and variety of VRET methods. VRET may be an effective alternative to current treatments and shows promise for the treatment of PTSD patients that have not responded to previous treatment. Future research should focus on high quality RCTs, including information on side effects and adverse events, with sufficient numbers of participants. This study recognizes a research gap regarding the efficacy of ARET, while it may have potential for PTSD treatment.

In order to determine the impact of the epigenetic response to traumatic stress on post-traumatic stress disorder (PTSD), this study examined longitudinal changes of genome-wide blood DNA methylation profiles in relation to the development of PTSD symptoms in two prospective military cohorts (one discovery and one replication data set). In the first cohort consisting of male Dutch military servicemen (n=93), the emergence of PTSD symptoms over a deployment period to a combat zone was significantly associated with alterations in DNA methylation levels at 17 genomic positions and 12 genomic regions. Evidence for mediation of the relation between combat trauma and PTSD symptoms by longitudinal changes in DNA methylation was observed at several positions and regions. Bioinformatic analyses of the reported associations identified significant enrichment in several pathways relevant for symptoms of PTSD. Targeted analyses of the significant findings from the discovery sample in an independent prospective cohort of male US marines (n=98) replicated the observed relation between decreases in DNA methylation levels and PTSD symptoms at genomic regions in ZFP57, RNF39 and HIST1H2APS2. Together, our study pinpoints three novel genomic regions where longitudinal decreases in DNA methylation across the period of exposure to combat trauma marks susceptibility for PTSD.

This paper discusses the design and analysis of planar circularly symmetric (PCS) electromagnetic band gap (EBG) structures for reducing the surface waves excited by printed antennas on dense dielectric substrates. The key advantage of the circularly symmetric geometries is that a surface wave generated by a source located at its center experiences the same band gap effect in all radial directions. To obtain simple design rules of the PCS-EBGs for the optimization of the bandwidth, an equivalence is established between 2-D-EBGs and PCS-EBGs. Integrated planar printed antennas with bandwidths up to 20% are designed, manufactured and tested.

Calculation of evaporative heat loss is essential to heat balance calculations. Despite recognition that the value for latent heat of evaporation, used in these calculations, may not always reflect the real cooling benefit to the body, only limited quantitative data on this is available, which has found little use in recent literature. In this experiment a thermal manikin, (MTNW, Seattle, WA) was used to determine the effective cooling power of moisture evaporation. The manikin measures both heat loss and mass loss independently, allowing a direct calculation of an effective latent heat of evaporation (λeff). The location of the evaporation was varied: from the skin or from the underwear or from the outerwear. Outerwear of different permeabilities was used, and different numbers of layers were used. Tests took place in 20°C, 0.5 m/s at different humidities and were performed both dry and with a wet layer, allowing the breakdown of heat loss in dry and evaporative components. For evaporation from the skin, λeff is close to the theoretical value (2,430 J/g) but starts to drop when more clothing is worn, e.g., by 11% for underwear and permeable coverall. When evaporation is from the underwear, λeff reduction is 28% wearing a permeable outer. When evaporation is from the outermost layer only, the reduction exceeds 62% (no base layer), increasing toward 80% with more layers between skin and wet outerwear. In semi- and impermeable outerwear, the added effect of condensation in the clothing opposes this effect. A general formula for the calculation of λeff was developed.

BACKGROUND: Smaller hippocampal volume has often been observed in patients with post-traumatic stress disorder (PTSD). However, there is no consensus whether this is a result of stress/trauma exposure, or constitutes a vulnerability factor for the development of PTSD. Second, it is unclear whether hippocampal volume normalizes with successful treatment of PTSD, or whether a smaller hippocampus is a risk factor for the persistence of PTSD. METHOD: Magnetic resonance imaging (MRI) scans and clinical interviews were collected from 47 war veterans with PTSD, 25 healthy war veterans (combat controls) and 25 healthy non-military controls. All veterans were scanned a second time with a 6- to 8-month interval, during which PTSD patients received trauma-focused therapy. Based on post-treatment PTSD symptoms, patients were divided into a PTSD group who was in remission (n = 22) and a group in whom PTSD symptoms persisted (n = 22). MRI data were analysed with Freesurfer. RESULTS: Smaller left hippocampal volume was observed in PTSD patients compared with both control groups. Hippocampal volume of the combat controls did not differ from healthy controls. Second, pre- and post-treatment analyses of the PTSD patients and combat controls revealed reduced (left) hippocampal volume only in the persistent patients at both time points. Importantly, hippocampal volume did not change with treatment. CONCLUSIONS: Our findings suggest that a smaller (left) hippocampus is not the result of stress/trauma exposure. Furthermore, hippocampal volume does not increase with successful treatment. Instead, we demonstrate for the first time that a smaller (left) hippocampus constitutes a risk factor for the persistence of PTSD.

In this paper the ultrawide-band properties of a long slot array are described. The study provides the rigorously derived Green's function (GF) for an infinite long slot array. From these GF active impedances and radiation patterns for various cases were obtained. The ultrawide bandwidths and the array performances of such apertures are highlighted, providing physical insights to understand the mathematical formulation throughout the paper.

Epigenetic differences may help to distinguish between PTSD cases and trauma-exposed controls. Here, we describe the results of the largest DNA methylation meta-analysis of PTSD to date. Ten cohorts, military and civilian, contribute blood-derived DNA methylation data from 1,896 PTSD cases and trauma-exposed controls. Four CpG sites within the aryl-hydrocarbon receptor repressor (AHRR) associate with PTSD after adjustment for multiple comparisons, with lower DNA methylation in PTSD cases relative to controls. Although AHRR methylation is known to associate with smoking, the AHRR association with PTSD is most pronounced in non-smokers, suggesting the result was independent of smoking status. Evaluation of metabolomics data reveals that AHRR methylation associated with kynurenine levels, which are lower among subjects with PTSD. This study supports epigenetic differences in those with PTSD and suggests a role for decreased kynurenine as a contributor to immune dysregulation in PTSD.

An efficient directive antenna is described that can be used to realize essentially non dispersive links over extremely large bandwidths. The antenna is a significantly enhanced version of previously proposed Leaky Lens antennas that use a frequency independent leaky slot radiation mechanism. A theoretical breakthrough now allows the use of this mechanism also in the presence of purely planar structures. This step allows the realization of the feed of a leaky lens antenna in a unique planar structure that is then glued to a standard circularly symmetric elliptical dielectric lens, as integrated technology requires in the mm and sub-mm wave domains. The first part of this sequence deals with a theoretical breakthrough, the consequent antenna concept and a description of the basic physical mechanisms inside and outside the lens antenna. It is shown that Leaky Lens antennas have the potential to be used to realize antenna links over bands exceeding a decade with minimal dispersion, high efficiency and high directivity. The second part of this sequence deals with the demonstration of these claims via the measurement of two prototypes.

The threat of cascading failures across critical infrastructures has been identified as a key challenge for governments. Cascading failure is seen as potentially catastrophic, extremely difficult to predict and increasingly likely to happen. Infrastructures are largely privately operated and private actors are thought to under‐invest in mitigating this threat. Consequently, experts have demanded a more dominant role for government, including the use of regulation. Empirical evidence on cascading failure is, however, extremely scarce. This paper analyses new data drawn from news reports on incidents. We find that, contrary to current thinking, cascades are not rare. Neither do they indicate a wide array of unknown dependencies across infrastructures. Rather, we find a small number of focused, unidirectional pathways around two infrastructures: energy and telecommunications. We also found that most cascades were stopped quickly, in contrast to the oft‐cited ‘domino effect'. These findings undermine the case for more intrusive public oversight of critical infrastructures.