Vertex discard occlusion culling

Performing visibility determination in densely occluded environments is essential to avoid rendering unnecessary objects and achieve high frame rates. In this work we present an implementation of the image space Occlusion Culling algorithm done completely in GPU, avoiding the latency introduced by returning the visibility results to the CPU. Our algorithm utilizes the GPU rendering power to construct the Occlusion Map and then performs the image space visibility test by splitting the region of the screen space occludees into parallelizable blocks. Our implementation is especially applicable for lowend graphics hardware and the visibility results are accessible by GPU shaders. It can be applied with excellent results in scenes where pixel shaders alter the depth values of the pixels, without interfering with hardware Early-Z culling methods. We demonstrate the benefits and show the results of this method in real-time densely occluded scenes.WCGIV - XI Workshop computación gráfica, imágenes y visualizaciónRed de Universidades con Carreras en Informática (RedUNCI

Techniques for an image space occlusion culling engine

In this work we present several techniques applied to implement an Image Space Software Occlusion Culling Engine to increase the speed of rendering general dynamic scenes with high depth complexity. This conservative culling method is based on a tiled Occlusion Map that is updated only when needed, deferring and even avoiding the expensive per pixel rasterization process. We show how the tiles become a useful way to increase the speed of visibility tests. Finally we describe how different parts of the engine were parallelized using OpenMP directives and SIMD instructions.Eje: Workshop Computación gráfica, imágenes y visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI

COMEPA (COVID-19 Medicina Policlinico Palermo): a study in hospitalized patients.

Coronavirus disease 2019 (COVID-19) has dramatically changed our lives. In the past months, hospitals were saturated of patients; therefore, it is still important to have simple and standardized prognostic factors and to evaluate the efficacy and safety of medications commonly used for COVID-19. We aimed to collect data of the patients hospitalized in Internal Medicine and Geriatrics Wards at the University Hospital (Policlinico) ‘P. Giaccone’ in Palermo, Italy (COMEPA, COVID-19 Medicina Policlinico Palermo), with the main purpose of finding prognostic tools that can be easily used in clinical practice in order to identify patients hospitalized for/with COVID-19 at higher risk of negative outcomes, such as mortality, transfer to Intensive Care Unit (ICU) and institutionalization, as well as evaluating the efficacy/safety of medications commonly used for COVID-19. For reaching these aims, the medical records of approximately 600 patients will be recorded, having data on several parameters and including as outcomes mortality, ICU placement, institutionalization. With the COMEPA study, we therefore plan to update current literature, giving new data on prognostic factors and on the efficacy/safety of some medications used for COVID-19

Lower Limb Muscle Strength and Muscle Mass Are Associated With Incident Symptomatic Knee Osteoarthritis: A Longitudinal Cohort Study

Recent literature suggests that sarcopenia, often represented by low lower limbs muscle mass and strength, can be considered a potential risk factor for knee osteoarthritis (OA), but the available literature is still limited. We therefore aimed to investigate whether sarcopenia is associated with a higher risk of radiographic (ROA) and symptomatic knee OA (SxOA) in a large cohort of North American people in the context of the OA initiative. Sarcopenia at baseline was diagnosed in case of low skeletal muscle mass (i.e., lower skeletal mass index) and poor performance in the chair stands test. The outcomes of interest for this study included ROA (radiographical osteoarthritis) if a knee developed a Kellgren and Lawrence (KL) grade ≥2 at follow-up, and SxOA (symptomatic osteoarthritis) defined as new onset of a combination of painful knee OA. Altogether, 2,492 older participants (mean age: 68.4 years, 61.4% females) were included. At baseline, sarcopenia was present in 6.1% of the population. No significant difference in ROA prevalence was observed between those with and without sarcopenia (p=0.76), whilst people with sarcopenia reported a significant higher prevalence of SxOA (p<0.0001). Using a logistic regression analysis, adjusting for potential confounders at baseline and the diagnosis of sarcopenia during follow-up, sarcopenia was associated with a higher incidence of knee SxOA (odds ratio, OR=2.29; 95%CI [confidence interval]: 1.42-3.71; p=0.001), but not knee ROA (OR=1.48; 95%CI: 0.53-4.10; p=0.45). In conclusion, sarcopenia could be associated with a higher risk of negative knee OA outcomes, in particular symptomatic forms

Multidimensional prognostic index and the risk of fractures: an 8-year longitudinal cohort study in the Osteoarthritis Initiative

Summary: In this longitudinal study, with a follow-up of 8 years, multidimensional prognostic index (MPI), a product of the comprehensive geriatric assessment, significantly predicted the onset of fractures in older people affected by knee osteoarthritis. Purpose: Frailty may be associated with higher fracture risk, but limited research has been carried out using a multidimensional approach to frailty assessment and diagnosis. The present research aimed to investigate whether the MPI, based on comprehensive geriatric assessment (CGA), is associated with the risk of fractures in the Osteoarthritis Initiative (OAI) study. Methods: Community-dwellers affected by knee OA or at high risk for this condition were followed-up for 8 years. A standardized CGA including information on functional, nutritional, mood, comorbidity, medication, quality of life, and co-habitation status was used to calculate the MPI. Fractures were diagnosed using self-reported information. Cox’s regression analysis was carried out and results are reported as hazard ratios (HRs), with their 95% confidence intervals (CIs), adjusted for potential confounders. Results: The sample consisted of 4024 individuals (mean age 61.0 years, females = 59.0%). People with incident fractures had a significant higher MPI baseline value than those without (0.42 ± 0.18 vs. 0.40 ± 0.17). After adjusting for several potential confounders, people with an MPI over 0.66 (HR = 1.49; 95%CI: 1.11–2.00) experienced a higher risk of fractures. An increase in 0.10 point in MPI score corresponded to an increase in fracture risk of 4% (HR = 1.04; 95%CI: 1.008–1.07). Higher MPI values were also associated with a higher risk of non-vertebral clinical fractures. Conclusion: Higher MPI values at baseline were associated with an increased risk of fractures, reinforcing the importance of CGA in predicting fractures in older people affected by knee OA. © 2021, The Author(s)

Tyr682 in the Aβ-precursor protein intracellular domain regulates synaptic connectivity, cholinergic function, and cognitive performance.

Processing of Aβ-precursor protein (APP) plays an important role in Alzheimer's disease (AD) pathogenesis. The APP intracellular domain contains residues important in regulating APP function and processing, in particular the 682YENPTY687 motif. To dissect the functions of this sequence in vivo, we created an APP knock-in allele mutating Y682 to Gly (APP(YG/YG) mice). This mutation alters the processing of APP and TrkA signaling and leads to postnatal lethality and neuromuscular synapse defects when expressed on an APP-like protein 2 KO background. This evidence prompted us to characterize further the APP(YG/YG) mice. Here, we show that APP(YG/YG) mice develop aging-dependent decline in cognitive and neuromuscular functions, a progressive reduction in dendritic spines, cholinergic tone, and TrkA levels in brain regions governing cognitive and motor functions. These data are consistent with our previous findings linking NGF and APP signaling and suggest a causal relationship between altered synaptic connectivity, cholinergic tone depression and TrkA signaling deficit, and cognitive and neuromuscular decline in APP(YG/YG) mice. The profound deficits caused by the Y682 mutation underscore the biological importance of APP and indicate that APP(YG/YG) are a valuable mouse model to study APP functions in physiological and pathological processes

Toward an Astrochronology-Based Age-Model for a Messinian Pre-Evaporitic Succession: The Example of Torrente Vaccarizzo Section in Sicily (Italy)

Tectonic, paleoenvironmental, and paleoclimatic unstable conditions preceding the onset of the Messinian Salinity Crisis (MSC) highly affected marine life. Changes in calcareous plankton association are overall registered in the Mediterranean. They consist of a general transition from abundant and well-diversified planktonic associations to strictly oligotypic assemblages that precede their total disappearance at the onset of evaporitic precipitation. In this work, an accurate quantitative analysis of calcareous plankton, both foraminifers and nannofossils, has been carried out in the Torrente Vaccarizzo Section of Sicily (southern Italy). The aim is to independently define a chronostratigraphic pattern of bioevents preceding the MSC in the absence of magnetostratigraphic or radiometric constraints. The fluctuating abundance of the genus Orbulina fits well with the 100 ky Eccentricity maxima, and it is successfully applied to build an astronomically calibrated age-model for the section. On this basis, all the biohorizons have been recalibrated and discussed with regard to the previous literature. Abundant influxes of selected species demonstrated to be of local significance since they are highly affected by paleoenvironmental and paleoclimatic conditions. A chronological sequence of foraminifer and nannofossil events marks the onset of the MSC with a derived age of 5.957 My, which agrees well with previous findings from other Mediterranean sections. This methodology and the new biostratigraphic events may be useful for future studies on pre-evaporitic successions of the Mediterranean

Techniques for an image space occlusion culling engine

In this work we present several techniques applied to implement an Image Space Software Occlusion Culling Engine to increase the speed of rendering general dynamic scenes with high depth complexity. This conservative culling method is based on a tiled Occlusion Map that is updated only when needed, deferring and even avoiding the expensive per pixel rasterization process. We show how the tiles become a useful way to increase the speed of visibility tests. Finally we describe how different parts of the engine were parallelized using OpenMP directives and SIMD instructions.Eje: Workshop Computación gráfica, imágenes y visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI

Implementing software occlusion culling for real-time applications

The visualization of complex virtual scenes can be significantly accelerated by applying Occlusion Culling. In this work we introduce a variant of the Hierarchical Occlusion Map method to be used in Real-Time applications. To avoid using real objects geometry we generate specialized conservative Occluders based on Axis Aligned Bounding Boxes which are converted into coplanar quads and then rasterized in CPU using a downscaled Depth Buffer. We implement this method in a 3D scene using a software occlusion map rasterizer module specifically optimized to rasterize Occluder quads into a Depth Buffer. We demonstrate that this approach effectively increases the number of occluded objects without generating significant runtime overhead.Eje: Workshop Computación gráfica, imágenes y visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI