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Actionable Open-Source Intelligence Architecture for Cold Case Investigations
Get PDFThe number of unsolved homicides in the Netherlands has gradually stacked up over the past few decades resulting in more than 1700 “cold cases” as of 2024. To tackle this problem, this paper presents a socio-technical system that facilitates the semi-automated collection and derivation of actionable intelligence from publicly available information for cold case investigations. The proposed system is designed using a multi-disciplinary approach by integrating solutions from the domains of homicide, ethics and philosophy, intelligence studies and computer science. Additionally, existing requirement engineering literature was used to identify the necessary requirements needed to design the proposed system. Thereby ensuring the safety, security and responsible use of OSINT for cold case investigations. We hope that the proposed socio-technical system can help mitigate cold cases and thus contribute towards the social goo
Evaluation of DNA-poli:Study protocol of a randomized controlled trial to assess a digital platform for family cascade genetic testing and predictive genetic counseling
Get PDFPurpose: The current uptake of predictive genetic counseling among at-risk relatives (ARRs) for cardiogenetic diseases is suboptimal, with 40% to 50% of ARRs undergoing testing within 1 to 3 years after disclosure. Digital technologies are increasingly proposed to improve accessibility, efficiency, and uptake of predictive genetic counseling and, if desired, predictive genetic testing. Therefore, DNA-poli was developed: a digital platform providing family communication support and pre- and posttest genetic counseling for ARRs. Here, we describe the study protocol for a randomized controlled trial evaluating DNA-poli in clinical practice. Methods: A noninferiority multicenter randomized controlled trial with parallel group design will be conducted. The intervention group using the DNA-poli platform will be compared with a control group receiving regular counseling. Probands with genetic hypertrophic or dilated cardiomyopathy will be included along with their ARRs and physicians. The primary outcome is the uptake of cardiogenetic counseling 6- and 12-months after result disclosure and stakeholders’ experiences. Secondary outcomes are informed decision making in ARRs, empowerment, and satisfaction in all stakeholder groups. In addition, the efficiency of consultations and the genetic care process will be analyzed. Descriptive and inferential statistics will be performed to analyze data. Discussion: This study aims to provide insight into the potential of digitalizing the cascade genetic testing process in cardiogenetics. Demonstrating noninferiority of the DNA-poli pathway compared with standard care could have major implications, suggesting that counseling supported by digital tools is at least equally effective. This may enhance the cascade genetic testing process, uptake, and efficiency while maintaining high quality standards.</p
Independent Predictors for Operative Treatment of Chronic Subdural Hematoma
Get PDFObjectives: Treatment of chronic subdural hematoma (CSDH) can be conservative or operative. Since clinical guidelines are lacking, a large variation in daily management of CSDH exists. We aimed to quantify the number of CSDH patients that are treated operatively and conservatively and to develop a prediction model that provides insight into the arguments behind the choice for operative treatment.Methods: All consecutive CSDH patients ≥ 18 years that were treated in three neurosurgical centers in the Netherlands between 2003 and 2019 were retrospectively included. Our outcome measure was the decision for operative treatment after initial diagnosis. Combining conventional multivariable logistic regression analysis and machine learning, four prediction models were developed and compared. The prediction model with the best performance was used for further analyses.Results: Of 684 included patients (29% female, median age 75 years), 428 (63%) were treated operatively. The multivariable logistic regression model performed best with an area under the curve of 0.90, a sensitivity of 0.87, and a specificity of 0.78. Independent predictors for operative treatment were treating facility, younger age, premorbid mRS ≤ 1, focal neurological deficit, cognitive impairment, and MGS score on admission, larger hematoma volume, and ≥ 10 mm midline shift on baseline CT. The highest predictive value for operative treatment was found for treating facility, hematoma volume, and ≥ 10 mm midline shift.Conclusion: While most CSDH patients are treated operatively, over a third are treated conservatively. Decisions for operative treatment are influenced by premorbid level of functioning, symptoms on admission, CT parameters, and, notably, interhospital variation, highlighting the need for standardized treatment guidelines.</p
Unilaterally Rotating Vertebrae:A Unique Movement Behaviour Arising from Wedged Intervertebral Discs in Scoliosis Condition
Get PDFScoliosis condition wedges the intervertebral discs. Once wedged, the core (nucleus pulposus) of a disc migrates permanently off the centre of the annulus fibrosus. In severely wedged discs, the core is pushed all the way towards a limit of its range of motion. As such, these discs hypothetically may lose their capability of wedging further as they cannot surpass the limit. However, this is yet to be studied. On a dataset of X-rays of 9 scoliotic patients, we studied the rotations of 126 vertebrae with respect to their inferior vertebrae. The rotations were measured for lateral movements towards four different positions in the coronal plane. We found that almost half of the vertebrae, irrespective of the spine movement direction, always rotate in the same direction. For example, in both left and right bending spine movements, these vertebrae rotate only towards one side (either left or right), while the rest can rotate both leftwards and rightwards following the spine movement direction. Such unilateral rotational behaviour can have significant indications for scoliosis surgery simulations. In surgery, the spine is subject to high forces to be straightened and a scoliosis model that does not support this unique behaviour may overestimate the spine straightness and produce misleading predictive information, negatively affecting the surgery planning.</p
Formation of equiaxed grains in pure iron during laser powder bed fusion
Get PDFMicrostructural evolution of commercially pure (CP) iron (Fe) fabricated by Laser Powder Bed Fusion (LPBF) was studied to investigate the mechanisms responsible for the formation of equiaxed grains during additive manufacturing, a surprising phenomenon in the additive manufacturing of cubic metals, which normally produces columnar grains. Detailed electron microscopy was performed on the LPBF bulk, adjacent laser tracks, and single-track samples to examine solidification and phase transformation sequences with and without reheating from neighbouring tracks or subsequent layers. The microstructure throughout the LPBF bulk, including the top layer with no reheating from above, was dominated by equiaxed grains with weak texture. In contrast, a single laser track consisted of lath-shaped colonies within prior columnar grains, creating a Widmanstätten pattern. Reheating from neighbouring laser tracks was sufficient to gradually transform these lath-shaped structures into equiaxed grains via recrystallisation and grain growth. Electron backscatter diffraction (EBSD) analysis revealed a transformation path of Liquid→δ-BCC→γ-FCC→α-BCC, in contrast to previously proposed Liquid→δ-BCC→α-BCC where the absence of γ-FCC due to rapid cooling was assumed. This was evidenced by reconstructed columnar γ-FCC from α-BCC EBSD data assuming FCC and BCC orientation relationships (ORs), as well as misorientation relationships across a wide range of specimens. The misorientation distributions were also studied to shed light on the early stages of microstructural development, the potential inheritance of the initial γ microstructure by the resulting α, and the progress of recrystallisation and grain growth throughout the process.</p
Boosting Revisited:Benchmarking and Advancing LP-Based Ensemble Methods
Get PDFDespite their theoretical appeal, totally corrective boosting methods based on linear programming have received limited empirical attention. In this paper, we conduct the first large-scale experimental study of six LP-based boosting formulations, including two novel methods, NM-Boost and QRLP-Boost, across 20 diverse datasets. We evaluate the use of both heuristic and optimal base learners within these formulations, and analyze not only accuracy, but also ensemble sparsity, margin distribution, anytime performance, and hyperparameter sensitivity. We show that totally corrective methods can outperform or match state-of-the-art heuristics like XGBoost and LightGBM when using shallow trees, while producing significantly sparser ensembles. We further show that these methods can thin pre-trained ensembles without sacrificing performance, and we highlight both the strengths and limitations of using optimal decision trees in this context
Identifying mineral chemistry variation with EMIT spaceborne hyperspectral data: a proxy for fluid composition in a high-sulphidation epithermal system.
Get PDFBiomedical β-titanium alloys from pure metal powders - Key role of Sn during additive manufacturing
Get PDFAdditive manufacturing of β -Ti alloys offers a transformative pathway for the development of patient-specific implants tailored to the individual’s needs. While β -Ti alloys are able to reduce stress-shielding effects, the inherent thermal treatment during the manufacturing process inevitably leads to elastic stiffening and embrittlement due to the formation of ω i s o precipitates. In this study, we show that ternary additions of Sn (3 at.%) to a Ti-12at.%Cr alloy, produced by in-situ alloying of elemental powders during laser powder bed fusion, mitigate the effects of thermal history by impeding the decomposition process during repeated thermal cycling that precedes the ω transformation. While the Sn-free alloy underwent a pronounced ω i s o formation accompanied by an increase in Young’s modulus of ≈ 30 % already during printing, the Sn-added alloy maintained a lower Young’s modulus of ≈ 83 ± 5 GPa with no apparent ω i s o precipitation, similar to the conventionally produced alloy. This greatly improved resistance to cyclic reheating is also sustained during long-term low-temperature ageing, whereas the ω i s o formation proceeded unhindered in the Sn-free alloy. In addition to retaining its favourable elastic properties, the alloy exhibited a high corrosion stability in a simulated physiological environment with a current density below 4 µA cm−2 around the body potential. These results highlight the key role that Sn can play in alloy design for additive manufacturing routes. The mitigating effect of Sn as a ternary addition to β -Ti alloys enables their reliable printing, with in-situ alloying approaches opening up possibilities for multi-material alloys compositionally tuned in order to respond to local loading conditions.</p
Nanofabrication of sharp conductive diamond tip probe chips and their application in reverse tip sample scanning probe microscopy
Get PDFRecently, a new scanning probe microscopy (SPM) concept called reverse tip sample scanning probe microscopy (RTS SPM) was introduced. Here, a sample is mounted at the end of a cantilever beam and scans over a tip that is integrated into an array of hundreds of SPM tips, overcoming one of the major limitations of the SPM technique, namely, the time-consuming and experiment-interrupting manual tip exchange step. However, to fully exploit this novel approach, a chip with an array of densely packed, nanometer-sharp, and durable SPM tips is essential. Therefore, we have developed a fabrication process to integrate such an array of sharp, high aspect ratio, doped diamond tips – referred to as hedgehog full diamond tip (HFDT) – into so-called probe chips, facilitating high-resolution SPM measurements and enabling rapid and seamless sample movement from one tip to another within the RTS SPM framework. An array of pyramidally shaped, doped diamond tips is fabricated through consecutive molding and diamond deposition steps. A supporting membrane is formed by metal deposition and electroplating, followed by selective underetching of the silicon substrate to release the tip array membrane and enable probe chip assembly. Finally, a self-patterned dry etching step is employed to generate multiple nanoscopic sharp tips on top of the base diamond pyramids. In this work, we present our developed and optimized probe chip technology and demonstrate its high electrical conductivity, robustness under high tip load force, and excellent spatial resolution, rendering it highly suitable for diverse electrical SPM measurement modes.</p
All in search of the missing:Citizen participation in missing person searches
Get PDFIn the Netherlands, approximately 30,000 people are reported missing to the police each year. In some cases, these disappearances lead to large-scale search efforts organized by citizens. Such citizen-led searches present both opportunities and risks. Citizens can serve as valuable additional eyes and ears, allowing a larger area to be covered. However, these searches can also destroy traces or evidence, or result in a lack of oversight and coordination. Often, the police have little or no formal authority to prevent or direct citizen search efforts.The aim of this dissertation is to gain a deeper understanding of how citizens participate in searches for missing persons. It examines how citizens and the police collaborate, what psychological factors motivate citizens to take part in search efforts and investigators to involve them, and how technology can be used to support citizens during searches.The dissertation consists of five studies. The first is a case study exploring the collaboration between citizens and the police in an actual missing person case. The next two are survey studies that explain citizens’ intentions to participate in searches based on characteristics of the disappearance and on cognitive and affective factors in potential searchers. These studies draw on the Theory of Planned Behavior and Community Engagement Theory. A third survey study examines investigators’ intentions to involve citizens, again from the perspective of the Theory of Planned Behavior. The final study employs a quasi-experimental design to investigate the impact of a specially developed mobile application on a citizen-organized search effort.Overall, the dissertation demonstrates that citizen participation in missing person searches is not static but dynamic, influenced by contextual, cognitive, and affective factors. It also highlights both the advantages and limitations of technological support for citizen-led searches