230 research outputs found
Recent advances in karst research: from theory to fieldwork and applications
Karst landscapes and karst aquifers, which are composed of a variety of soluble rocks such as salt, gypsum, anhydrite, limestone, dolomite and quartzite, are fascinating areas of study. As karst rocks are abundant on the Earth's surface, the fast evolution of karst landscapes and the rapid flow of water through karst aquifers present challenges from a number of different perspectives. This collection of 25 papers deals with different aspects of these challenges, including karst geology, geomorphology and speleogenesis, karst hydrogeology, karst modelling, and karst hazards and management. Together these papers provide a state-of-the-art review of the current challenges and solutions in describing karst from a scientific perspective
360-degree Video Stitching for Dual-fisheye Lens Cameras Based On Rigid Moving Least Squares
Dual-fisheye lens cameras are becoming popular for 360-degree video capture,
especially for User-generated content (UGC), since they are affordable and
portable. Images generated by the dual-fisheye cameras have limited overlap and
hence require non-conventional stitching techniques to produce high-quality
360x180-degree panoramas. This paper introduces a novel method to align these
images using interpolation grids based on rigid moving least squares.
Furthermore, jitter is the critical issue arising when one applies the
image-based stitching algorithms to video. It stems from the unconstrained
movement of stitching boundary from one frame to another. Therefore, we also
propose a new algorithm to maintain the temporal coherence of stitching
boundary to provide jitter-free 360-degree videos. Results show that the method
proposed in this paper can produce higher quality stitched images and videos
than prior work.Comment: Preprint versio
Correction to: Computed tomography angiography versus Agatston score for diagnosis of coronary artery disease in patients with stable chest pain: individual patient data meta-analysis of the international COME-CCT Consortium
Clinical outcomes of ultrasound-assisted coagulation monitoring-adjusted catheter-directed thrombolysis for acute pulmonary embolism
BACKGROUND
Ultrasound-assisted catheter-directed thrombolysis (USAT) may reverse right ventricular dysfunction due to acute pulmonary embolism (PE) with a favorable safety profile.
METHODS
We studied intermediate-high- and high-risk acute PE patients who underwent USAT at the University Hospital Zurich, 2018-2022. The USAT regimen included alteplase 10Â mg per catheter over 15Â h, therapeutic-dosed heparin, and dosage adaptations based on routinely monitored coagulation parameters, notably anti-factor Xa activity and fibrinogen. We focused on the mean pulmonary arterial pressure (mPAP) and the National Early Warning Score (NEWS) before and after USAT, and reported the incidence of hemodynamic decompensation, PE recurrence, major bleeding, and death over 30Â days.
RESULTS
We included 161 patients: 96 (59.6Â %) were men and the mean age was 67.8 (SD 14.6) years. Mean PAP decreased from a mean of 35.6 (SD 9.8) to 25.6 (SD 8.2) mmHg, whereas the NEWS decreased from a median of 5 (Q1-Q3 4-6) to 3 (Q1-Q3 2-4) points. No cases of hemodynamic decompensation occurred. One (0.6Â %) patient had an episode of recurrent PE. Two (1.2Â %) major bleeding events occurred, including one (0.6Â %) intracranial, fatal hemorrhage in a patient with high-risk PE, severe heparin overdosing, and a recent head trauma (with negative CT scan of the brain performed at baseline). No other deaths occurred.
CONCLUSIONS
USAT resulted in a rapid improvement of hemodynamic parameters among patients with intermediate-high risk acute PE and selected ones with high-risk acute PE, without any recorded deaths related to PE itself. A strategy including USAT, therapeutic-dosed heparin, and routinely monitored coagulation parameters may partly explain the overall very low rate of major bleeding
Low-dimensional controllability of brain networks
Network controllability is a powerful tool to study causal relationships in
complex systems and identify the driver nodes for steering the network dynamics
into desired states. However, due to ill-posed conditions, results become
unreliable when the number of drivers becomes too small compared to the network
size. This is a very common situation, particularly in real-world applications,
where the possibility to access multiple nodes at the same time is limited by
technological constraints, such as in the human brain. Although targeting
smaller network parts might improve accuracy, challenges may remain for
extremely unbalanced situations, when for example there is one single driver.
To address this problem, we developed a mathematical framework that combines
concepts from spectral graph theory and modern network science. Instead of
controlling the original network dynamics, we aimed to control its
low-dimensional embedding into the topological space derived from the network
Laplacian. By performing extensive simulations on synthetic networks, we showed
that a relatively low number of projected components is enough to improve the
overall control accuracy, notably when dealing with very few drivers. Based on
these findings, we introduced alternative low-dimensional controllability
metrics and used them to identify the main driver areas of the human connectome
obtained from N=6134 healthy individuals in the UK-biobank cohort. Results
revealed previously unappreciated influential regions compared to standard
approaches, enabled to draw control maps between distinct specialized
large-scale brain systems, and yielded an anatomically-based understanding of
hemispheric functional lateralization. Taken together, our results offered a
theoretically-grounded solution to deal with network controllability in
real-life applications and provided insights into the causal interactions of
the human brain
Mycobacterium tuberculosis Invasion of the Human Lung: First Contact
Early immune responses to Mycobacterium tuberculosis (Mtb) invasion of the human lung play a decisive role in the outcome of infection, leading to either rapid clearance of the pathogen or stable infection. Despite their critical impact on health and disease, these early host–pathogen interactions at the primary site of infection are still poorly understood. In vitro studies cannot fully reflect the complexity of the lung architecture and its impact on host–pathogen interactions, while animal models have their own limitations. In this study, we have investigated the initial responses in human lung tissue explants to Mtb infection, focusing primarily on gene expression patterns in different tissue-resident cell types. As first cell types confronted with pathogens invading the lung, alveolar macrophages, and epithelial cells displayed rapid proinflammatory chemokine and cytokine responses to Mtb infection. Other tissue-resident innate cells like gamma/delta T cells, mucosal associated invariant T cells, and natural killer cells showed partially similar but weaker responses, with a high degree of variability across different donors. Finally, we investigated the responses of tissue-resident innate lymphoid cells to the inflammatory milieu induced by Mtb infection. Our infection model provides a unique approach toward host–pathogen interactions at the natural port of Mtb entry and site of its implantation, i.e., the human lung. Our data provide a first detailed insight into the early responses of different relevant pulmonary cells in the alveolar microenvironment to contact with Mtb. These results can form the basis for the identification of host markers that orchestrate early host defense and provide resistance or susceptibility to stable Mtb infection
Aportes del estudio de los procesos de formación de sitio para el análisis de los restos humanos del sitio Laguna Muscar 2 (Lamadrid, Buenos Aires)
En este trabajo se presentan los resultados del análisis de un entierro humano altamente perturbado, recuperado en el sitio Laguna Muscar 2 (partido de Gral. Lamadrid, provincia de Buenos Aires). Los principales objetivos fueron caracterizar el entierro, determinar la modalidad del mismo y evaluar los procesos de formación responsables de su configuración final. Para esto se llevó a cabo la identificación y cuantificación de las unidades anatómicas, en conjunto con el estudio de las modificaciones tafonómicas y la distribución espacial de los elementos en la matriz sedimentaria. Los resultados indicaron que el entierro estaba conformado por un individuo femenino adulto, con deformación craneana artificial de tipo tabular erecta planofrontal y presencia de algunas patologÃas degenerativas. La modalidad de entierro fue determinada como primaria y el fechado radiocarbónico efectuado arrojó una edad de ca. 2500 años C14 AP. Los resultados mostraron la importancia de implementar el estudio de los procesos de formación en el análisis de conjuntos perturbados por animales de hábitos fosoriales. Finalmente, estos datos fueron discutidos junto con los estudios disponibles para la microrregión de la cuenca del arroyo Salado.In this article we present the results of the analysis of a significantly disturbed human burial, recovered at the archaeological site Laguna Muscar 2 (Lamadrid County, province of Buenos Aires). The main objectives were to characterize the burial, to determine the burial type, and to evaluate the site formation processes that were responsible for its final configuration. To achieve these goals, all the anatomical units were identified and quantified, taphonomic modifications were registered, and the spatial distribution of the elements in the sedimentary matrix was studied. The results indicated that the burial was composed by an adult female individual, with artificial (planofrontal) cranial deformation and some degenerative pathology. The type of burial was determined as primary and the radiocarbon date indicated an age of ca. 2500 years C14 AP. The results showed the importance of implementing the study of formation processes when analyzing assemblages disturbed by fossorial animals. Finally, the resulting data were discussed together with the studies available for the microregion of the Salado creek basin.Fil: Kaufmann, Cristian Ariel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; ArgentinaFil: Bellinzoni, Jonathan. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Sociales. Departamento de ArqueologÃa; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tandil; ArgentinaFil: Alvarez, MarÃa Clara. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; ArgentinaFil: Gonzalez, Mariela Edith. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; ArgentinaFil: Favier Dubois, Cristian Mario. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; ArgentinaFil: Barros, Maria Paula. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; Argentin
What Research Is Needed to Stop TB? Introducing the TB Research Movement
Christian Lienhardt and colleagues describe the development of the TB Research Movement, which aims to create a framework for concrete actions to harmonize and synergize TB research efforts globally
Effect of aging on thermal conductivity of fiber-reinforced aerogel composites: An X-ray tomography study
Silica aerogels display an ultra-low thermal conductivity (λ) and are used as thermal superinsulators. Here, we study the influence of aging and drying processes on the microstructure and thermal conductivity of fiber-reinforced silica aerogel composites. Glass wool-silica gel composites were aged for variable times, hydrophobized, and dried either at ambient pressure or from supercritical CO2 (scCO2). The X-ray micro- tomographic data display three distinct phases: silica aerogel, glass fibers, and macroscopic pores and cracks. The silica aerogel appears as a continuous medium in the tomograms because the spatial resolution (6–11 μm) is insufficient to resolve the aerogel mesopores (∼0.02–0.10 μm). For the composites prepared by ambient pressure drying, insufficient aging led to prominent drying shrinkage and cracking, and a high macro-porosity, as quantified by 3D image analysis. Insufficient aging also led to an increase in λ from 15.7 to 21.5 mW m−1 K−1. On the contrary, composites that were nearly free of cracks and displayed a constant λ of 16.3 ± 0.8 mW m−1 K−1 could be prepared by scCO2, independent of aging time. The thermal conductivity was reproduced from the macro-porosity to within 0.7 mW m−1 K−1 using simple thermal transport models consisting of thermal elements connected in series or parallel. Our results illustrate the usefulness of X-ray micro-tomography to quantify the 3D microstructure and its effects on the bulk composite properties and the data highlight the importance of aging for the production of low λ aerogel-fiber composites by ambient pressure drying
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