Illustrated argument for CT-scanning a whole car for the forensic investigation of projectile holes, defects, fragments and possible trajectories

Contemporary documentation of a car with bullet defects after a shooting incident can secure the usual tracks and gunshot residue, take photographs, and use trajectory rods and probes. Since the advent of the ”XXL-CT -Scanner” (Fraunhofer Institute, Germany), we have wondered if the advantages of volume scanning CT, already noted for forensic pathology, could be applied to cars. To this end, we damaged a small 3D-printed car model with an electric drill and added CT -dense material with a soldering iron, simulating linearly configured defect morphologies with metal particles. This model was CT -scanned and the resulting data visualized to illustrate how these visualizations can support reconstructive visualization of trajectories. Performing a real XXL-CT scan of a bullet-riddled car requires extensive preparation, transportation, and other logistical measures that are costly and time-consuming. Nonetheless, we suggest that this is a worthwhile research direction to explore

Classification of rib fracture types from postmortem computed tomography images using deep learning

Human or time resources can sometimes fall short in medical image diagnostics, and analyzing images in full detail can be a challenging task. With recent advances in artificial intelligence, an increasing number of systems have been developed to assist clinicians in their work. In this study, the objective was to train a model that can distinguish between various fracture types on different levels of hierarchical taxonomy and detect them on 2D-image representations of volumetric postmortem computed tomography (PMCT) data. We used a deep learning model based on the ResNet50 architecture that was pretrained on ImageNet data, and we used transfer learning to fine-tune it to our specific task. We trained our model to distinguish between “displaced,” “nondisplaced,” “ad latus,” “ad longitudinem cum contractione,” and “ad longitudinem cum distractione” fractures. Radiographs with no fractures were correctly predicted in 95–99% of cases. Nondisplaced fractures were correctly predicted in 80–86% of cases. Displaced fractures of the “ad latus” type were correctly predicted in 17–18% of cases. The other two displaced types of fractures, “ad longitudinem cum contractione” and “ad longitudinem cum distractione,” were correctly predicted in 70–75% and 64–75% of cases, respectively. The model achieved the best performance when the level of hierarchical taxonomy was high, while it had more difficulties when the level of hierarchical taxonomy was lower. Overall, deep learning techniques constitute a reliable solution for forensic pathologists and medical practitioners seeking to reduce workload

An algorithm for automatically generating gas, bone and foreign body visualizations from postmortem computed tomography data

Post mortem computed tomography (PMCT) can aid in localizing foreign bodies, bone fractures, and gas accumulations. The visualization of these findings play an important role in the communication of radiological findings. In this article, we present an algorithm for automated visualization of gas distributions on PMCT image data of the thorax and abdomen. The algorithm uses a combination of region growing segmentation and layering of different visualization methods to automatically generate overview images that depict radiopaque foreign bodies, bones and gas distributions in one image. The presented method was tested on 955 PMCT scans of the thorax and abdomen. The algorithm managed to generate useful images for all cases, visualizing foreign bodies as well as gas distribution. The most interesting cases are presented in this article. While this type of visualization cannot replace a real radiological analysis of the image data, it can provide a quick overview for briefings and image reports

A Mobile, Multi Camera Setup for 3D Full Body Imaging in Combination with Post-Mortem Computed Tomography Procedures

Three dimensional (3D) models of deceased and injured people in combination with 3D scans of injury causing objects can assist forensic investigations in reconstructing event scenes. Medical imaging techniques, such as post-mortem computed tomography (PMCT) and post-mortem magnetic resonance imaging (PMMR), have been successfully applied to forensic investigations and can add beneficial value to standard autopsy examinations. These imaging modalities can be helpful for 3D reconstructions, especially when internal findings, such as bone fractures, organ damage and internal bleeding, are relevant for the investigation. However, none of these techniques can adequately visualize pattern injuries, such as boot prints and bite marks, or any type of blunt force trauma that forms distinct discolorations on the body’s surface. This is why 3D surface imaging techniques have been introduced to the forensic community. Unfortunately, many commercially available optical scanning systems are cost intensive, time consuming and can only be applied before or after a CT scan has been performed. In this article, we present a mobile, multi-camera rig based on close-range photogrammetry that is inexpensive, fast in acquisition time and can be combined with automated CT scanning protocols. The multi-camera setup comprises seven digital single-lens reflex (DSLR) cameras that are mounted on a mobile frame. Each camera is equipped with a remote control that can trigger the shutter release of all cameras simultaneously. In combination with a medical CT scanner, image acquisition of the multi camera setup can be included into an automated CT scanning procedure. In our preliminary study, textured 3D models of one side of the body were created in less than 15 minutes. The photo acquisition time combined with the modified CT scanning protocols lasted 3:34 minutes whereas the subsequent computation of a textured 3D model based on a low resolution mesh lasted 10:55 minutes. The mobile, multi-camera setup can also be used manually in combination with examination couches, lifting carts and autopsy tables. Finally, the system is not limited to post-mortem investigations but can also be applied to living people and may be used in clinical settings

The sign problem across the QCD phase transition

The average phase factor of the QCD fermion determinant signals the strength of the QCD sign problem. We compute the average phase factor as a function of temperature and baryon chemical potential using a two-flavor NJL model. This allows us to study the strength of the sign problem at and above the chiral transition. It is discussed how the $U_A(1)$ anomaly affects the sign problem. Finally, we study the interplay between the sign problem and the endpoint of the chiral transition.Comment: 9 pages and 9 fig

Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions

Significant reductions in stratospheric ozone occur inside the polar vortices each spring when chlorine radicals produced by heterogeneous reactions on cold particle surfaces in winter destroy ozone mainly in two catalytic cycles, the ClO dimer cycle and the ClO/BrO cycle. Chlorofluorocarbons (CFCs), which are responsible for most of the chlorine currently present in the stratosphere, have been banned by the Montreal Protocol and its amendments, and the ozone layer is predicted to recover to 1980 levels within the next few decades. During the same period, however, climate change is expected to alter the temperature, circulation patterns and chemical composition in the stratosphere, and possible geo-engineering ventures to mitigate climate change may lead to additional changes. To realistically predict the response of the ozone layer to such influences requires the correct representation of all relevant processes. The European project RECONCILE has comprehensively addressed remaining questions in the context of polar ozone depletion, with the objective to quantify the rates of some of the most relevant, yet still uncertain physical and chemical processes. To this end RECONCILE used a broad approach of laboratory experiments, two field missions in the Arctic winter 2009/10 employing the high altitude research aircraft M55-Geophysica and an extensive match ozone sonde campaign, as well as microphysical and chemical transport modelling and data assimilation. Some of the main outcomes of RECONCILE are as follows: (1) vortex meteorology: the 2009/10 Arctic winter was unusually cold at stratospheric levels during the six-week period from mid-December 2009 until the end of January 2010, with reduced transport and mixing across the polar vortex edge; polar vortex stability and how it is influenced by dynamic processes in the troposphere has led to unprecedented, synoptic-scale stratospheric regions with temperatures below the frost point; in these regions stratospheric ice clouds have been observed, extending over >106km2 during more than 3 weeks. (2) Particle microphysics: heterogeneous nucleation of nitric acid trihydrate (NAT) particles in the absence of ice has been unambiguously demonstrated; conversely, the synoptic scale ice clouds also appear to nucleate heterogeneously; a variety of possible heterogeneous nuclei has been characterised by chemical analysis of the non-volatile fraction of the background aerosol; substantial formation of solid particles and denitrification via their sedimentation has been observed and model parameterizations have been improved. (3) Chemistry: strong evidence has been found for significant chlorine activation not only on polar stratospheric clouds (PSCs) but also on cold binary aerosol; laboratory experiments and field data on the ClOOCl photolysis rate and other kinetic parameters have been shown to be consistent with an adequate degree of certainty; no evidence has been found that would support the existence of yet unknown chemical mechanisms making a significant contribution to polar ozone loss. (4) Global modelling: results from process studies have been implemented in a prognostic chemistry climate model (CCM); simulations with improved parameterisations of processes relevant for polar ozone depletion are evaluated against satellite data and other long term records using data assimilation and detrended fluctuation analysis. Finally, measurements and process studies within RECONCILE were also applied to the winter 2010/11, when special meteorological conditions led to the highest chemical ozone loss ever observed in the Arctic. In addition to quantifying the 2010/11 ozone loss and to understand its causes including possible connections to climate change, its impacts were addressed, such as changes in surface ultraviolet (UV) radiation in the densely populated northern mid-latitudes

Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions : (RECONCILE) ; activities and results

The international research project RECONCILE has addressed central questions regarding polar ozone depletion, with the objective to quantify some of the most relevant yet still uncertain physical and chemical processes and thereby improve prognostic modelling capabilities to realistically predict the response of the ozone layer to climate change. This overview paper outlines the scope and the general approach of RECONCILE, and it provides a summary of observations and modelling in 2010 and 2011 that have generated an in many respects unprecedented dataset to study processes in the Arctic winter stratosphere. Principally, it summarises important outcomes of RECONCILE including (i) better constraints and enhanced consistency on the set of parameters governing catalytic ozone destruction cycles, (ii) a better understanding of the role of cold binary aerosols in heterogeneous chlorine activation, (iii) an improved scheme of polar stratospheric cloud (PSC) processes that includes heterogeneous nucleation of nitric acid trihydrate (NAT) and ice on non-volatile background aerosol leading to better model parameterisations with respect to denitrification, and (iv) long transient simulations with a chemistry-climate model (CCM) updated based on the results of RECONCILE that better reproduce past ozone trends in Antarctica and are deemed to produce more reliable predictions of future ozone trends. The process studies and the global simulations conducted in RECONCILE show that in the Arctic, ozone depletion uncertainties in the chemical and microphysical processes are now clearly smaller than the sensitivity to dynamic variability

Infection of the Central Nervous System, Sepsis and Amyotrophic Lateral Sclerosis

Severe infections may lead to chronic inflammation in the central nervous system (CNS) which may in turn play a role in the etiopathogenesis of amyotrophic lateral sclerosis (ALS). The relentless progression and invasive supportive treatments of ALS may on the other hand induce severe infections among ALS patients.The present study included 4,004 ALS patients identified from the Swedish Patient Register during 1991-2007 and 20,020 age and sex matched general population controls. Conditional logistic regression was used to estimate the odds ratios (ORs) of ALS given a previous hospitalization for CNS infection or sepsis. Cox models were used to estimate the hazard ratios (HRs) of hospitalization for CNS infection or sepsis after ALS diagnosis. Overall, previous CNS infection (OR: 1.3, 95% confidence interval [CI]: 0.8, 2.4) or sepsis (OR: 1.2, 95% CI: 0.9, 1.6) was not associated with ALS risk. However, compared to ALS free individuals, ALS cases were more likely to be hospitalized for sepsis after diagnosis (HR: 2.6, 95% CI: 1.9, 3.5). We did not observe a higher risk of CNS infection after ALS diagnosis.Our results suggest that acute and severe infections unlikely contribute to the development of ALS; however, ALS patients are at a higher risk of sepsis after diagnosis, compared to ALS free individuals