Bootstrapping Conditional GANs for Video Game Level Generation

Generative Adversarial Networks (GANs) have shown im-pressive results for image generation. However, GANs facechallenges in generating contents with certain types of con-straints, such as game levels. Specifically, it is difficult togenerate levels that have aesthetic appeal and are playable atthe same time. Additionally, because training data usually islimited, it is challenging to generate unique levels with cur-rent GANs. In this paper, we propose a new GAN architec-ture namedConditional Embedding Self-Attention Genera-tive Adversarial Network(CESAGAN) and a new bootstrap-ping training procedure. The CESAGAN is a modification ofthe self-attention GAN that incorporates an embedding fea-ture vector input to condition the training of the discriminatorand generator. This allows the network to model non-localdependency between game objects, and to count objects. Ad-ditionally, to reduce the number of levels necessary to trainthe GAN, we propose a bootstrapping mechanism in whichplayable generated levels are added to the training set. Theresults demonstrate that the new approach does not only gen-erate a larger number of levels that are playable but also gen-erates fewer duplicate levels compared to a standard GAN

Cemented horizons and hardpans in the coastal tablelands of Northeastern Brazil.

Horizons with varying degrees of cementation are a common feature of the soils from the coastal tablelands of Northeastern Brazil. In most cases, these horizons are represented by the following subsurface horizons: fragipan, duripan, ortstein, and placic. The aims of this study were to analyze differences regarding the development and the degree of expression of cementation in soils from the coastal tablelands of Northeastern Brazil: Planossolo Háplico (p-SX), Espodossolo Humilúvico (p-EK), Espodossolo Ferrihumilúvico (p-ESK), and Argissolo Acinzentado (p-PAC) pedons. The pedons studied displayed features related to drainage impediments. The cemented horizons from p-SX and p-EK had the same designation (Btgm), displaying a duric character that coincided with gleization features and are under podzolized horizons. In the p-ESK, the podzolization process is of such magnitude that it leads to the cementation of its own spodic horizons, which were both of the ortstein type (Bhsx and Bsm). In the p-PAC cementation is observed in two placic horizons and in the Btx/Bt horizon, as well as in the upper parts of the Bt/Btx horizon. Analysis of the micrographies from the cemented horizons showed predominance of a low porosity matrix. Such porosity is relatively greater in the horizons of ?x? subscript than in the horizons with duric character. The Fe segregation lines were notable in the cemented horizons from p-EK and p-PAC, which corroborates the presence of placic horizons in such pedons. The preponderance of kaolinite in the clay fraction was widely verified in all the cemented horizons analyzed. Water immersion tests were the criteria adopted to define the duric character of the Btgm horizons from p-SX and p-EK, and in the Bsm horizon from the p-ESK. These tests were also used to confirm field morphology. In most cases, the maximum values of Fe, Al, and Si, determined by different extractions, occurred in positions overlaying the cemented horizons, whether they were spodic or not. The extracts of the aqueous solution displayed a noticeable accumulation of Si in the cemented horizons, except in the p-PAC. The presence of argillans in all cemented horizons allows them to be defined as illuvial, with the exception of the placic horizons, regardless of the presence of podzolization processes. The cemented horizons were preponderantly apedal, with a matrix of little porosity. The Fe, Al, and Si contents extracted by acid ammonium oxalate were effective at highlighting the influence of compounds with a low degree of crystallinity in the morphology of cemented horizons

Antibacterial bioadhesive layer-by-layer coatings for orthopedic applications

In this study, thin LbL films were produced by combining the adhesive properties of the hyaluronic acidâ dopamine conjugate with the bioactivity and bactericidal properties of silver doped bioactive glass nanoparticles. The build-up of these films was investigated by quartz crystal microbalance with dissipation monitoring. LbL coatings were then constructed on a glass substrate for further characterization. We found that these antimicrobial bioinspired films display enhanced adhesive strength. In vitro bioactivity tests were performed by immersing them in simulated body fluid solution for 14 days where the constructed films promoted the formation of a bone-like apatite layer. From microbiological assays, it was found that coatings containing silver doped nanoparticles exhibited a remarkable antibacterial effect against Staphylococcus aureus and Escherichia coli cultures. Finally, in vitro cellular behavior tests showed enhanced cell adhesion, proliferation and viability for these antibacterial bioadhesive films. Therefore, the constructed thin films showed promising properties and evidenced great potential to be used as coatings for orthopedic implants.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT) and the European program FEDER/COMPETE for the financial support through project BioSeaGlue: EXPL/CTM-BIO/0646/2013 (FCOMP-01-0124-FEDER041105). This work was co-funded by ‘‘Programa Operacional Regional do Norte’’ (ON.2-O Novo Norte) under the ‘‘Quadro de Referência Estratégico Nacional’’ (QREN), through the ‘‘Fundo Europeu de Desenvolvimento Regional’’ (FEDER). E. T. also thanks the FCT investigator grant (IF/01390/2014)

Fast pseudo-CT synthesis from MRI T1-weighted images using a patch-based approach

MRI-based bone segmentation is a challenging task because bone tissue and air both present low signal intensity on MR images, making it difficult to accurately delimit the bone boundaries. However, estimating bone from MRI images may allow decreasing patient ionization by removing the need of patient-specific CT acquisition in several applications. In this work, we propose a fast GPU-based pseudo-CT generation from a patient-specific MRI T1-weighted image using a group-wise patch-based approach and a limited MRI and CT atlas dictionary. For every voxel in the input MR image, we compute the similarity of the patch containing that voxel with the patches of all MR images in the database, which lie in a certain anatomical neighborhood. The pseudo-CT is obtained as a local weighted linear combination of the CT values of the corresponding patches. The algorithm was implemented in a GPU. The use of patch-based techniques allows a fast and accurate estimation of the pseudo-CT from MR T1-weighted images, with a similar accuracy as the patient-specific CT. The experimental normalized cross correlation reaches 0.9324±0.0048 for an atlas with 10 datasets. The high NCC values indicate how our method can accurately approximate the patient-specific CT. The GPU implementation led to a substantial decrease in computational time making the approach suitable for real applications

Hacia una protonterapia adaptativa: Evaluando el potencial de la nnUNet para la segmentación de órganos en riesgo

La segmentación de órganos en riesgo es un proceso esencial en el tratamiento de protonterapia, especialmente en pacientes con cáncer de cabeza y cuello, donde la presencia de estructuras en riesgo es elevada. Debido a la necesidad de replanificación del tratamiento, así como a la gran carga de trabajo asociada a una delineación manual de las estructuras, es frecuente el uso de algoritmos automáticos de procesamiento de imagen para esta labor. En este marco se encuentra el trabajo propuesto, donde se prueba el potencial de la nnU-Net para la segmentación de 45 estructuras cerebrales. En este sentido, se entrenan cuatro modelos (un modelo bidimensional y tres tridimensionales a diferentes resoluciones) sobre 65 sujetos. Tras la comparación con métodos del estado del arte para la segmentación de estructuras cerebrales, destaca el potencial de la nnU-Net como herramienta para la segmentación de órganos en riesgo en la clínica, no solo por sus resultados, donde se obtiene un Coeficiente de Dice de 0.873 empleando arquitecturas tridimensionales; si no por su reducido tiempo de procesamiento (3:46min) y la robustez arrojada en la fase de test, donde se realiza una evaluación de incertidumbre con el objetivo de determinar la variabilidad de respuesta del modelo ante variaciones sistemáticas en la entrada

La gran erupción de hace 4.2 ka cal en Cerro Blanco, Zona Volcánica Central, Andes: nuevos datos sobre los depósitos eruptivos holocenos en la Puna sur y regiones adyacentes

The eruption of the Cerro Blanco Volcanic Complex, in the southern Puna, NW Argentina dated at 4410–4150 a cal BP, was investigated to produce new information on stratigraphy, geomorphology, physical volcanology, radiocarbon dating, petrography, and geochemistry. Identification of pre–, syn–, and post–caldera products allowed us to estimate the distribution of the Plinian fallout during the paroxysmal syn–caldera phase of the eruption. The new results provide evidence for a major rhyolitic explosive eruption that spread volcanic deposits over an area of ~500,000 km2, accumulating > 100 km3 of tephra (bulk volume). This last value exceeds the lower threshold of Volcanic Explosive Index (VEI) of 7. Ash-fall deposits mantled the region at distances > 400 km from source and thick pyroclastic-flow deposits filled neighbouring valleys up to 35 km away. This eruption is the largest documented during the past five millennia in the Central Volcanic Zone of the Andes, and is probably one of the largest Holocene explosive eruptions in the world. We have also identified two additional rhyolitic eruptions in the region from two other eruptive sources: one during the Early–Holocene and another in the Late–Holocene. The identification and characterisation of these significant volcanic events provide new constraints into regional Holocene geological and archaeological records, and offer extensive regional chronostratigraphic markers over a wide geographical area of South America.La erupción del Complejo Volcánico Cerro Blanco en el sur de la Puna, noroeste de Argentina (4410–4150 a BP) se investigó para obtener nueva información sobre estratigrafía, geomorfología, volcanología física, dataciones por radiocarbono, petrografía y geoquímica. La caracterización de los productos en relación a la evolución de la caldera de Cerro Blanco permitió estimar la distribución de los depósitos de ceniza de la fase paroxísmica Plineana de la erupción. Estos novedosos resultados evidencian una gran erupción explosiva riolítica que generó depósitos cineríticos en un área de aproximadamente 500.000 km2, acumulando > 100 km3 de tefra (volumen total). Este último valor supera el umbral inferior del Índice de Explosividad Volcánica (IEV) de 7. Los depósitos de caída de ceniza cubrieron la región, llegando a más de 400 km desde el Complejo Volcánico de Cerro Blanco, y los potentes depósitos de flujos piroclásticos rellenaron los valles vecinos alcanzando una distancia de 35 km. Esta erupción es la más grande documentada durante los últimos cinco milenios en la Zona Volcánica Central de los Andes y es probablemente una de las mayores erupciones explosivas holocenas del mundo. Además, se han identificado otras dos erupciones riolíticas en la región procedentes de otros dos centros eruptivos: una durante el Holoceno temprano y otra en el Holoceno tardío. La identificación y caracterización de estos grandes eventos volcánicos proporcionan nuevas guías para los registros geológicos y arqueológicos regionales del Holoceno, siendo marcadores cronostratigráficos de aplicación a una extensa área geográfica de América del Sur

Neuroimmune activation and increased brain aging in chronic pain patients after the COVID-19 pandemic onset

The COVID-19 pandemic has exerted a global impact on both physical and mental health, and clinical populations have been disproportionally affected. To date, however, the mechanisms underlying the deleterious effects of the pandemic on pre-existing clinical conditions remain unclear. Here we investigated whether the onset of the pandemic was associated with an increase in brain/blood levels of inflammatory markers and MRI-estimated brain age in patients with chronic low back pain (cLBP), irrespective of their infection history. A retrospective cohort study was conducted on 56 adult participants with cLBP (28 ‘Pre-Pandemic’, 28 ‘Pandemic’) using integrated Positron Emission Tomography/ Magnetic Resonance Imaging (PET/MRI) and the radioligand [11C]PBR28, which binds to the neuroinflammatory marker 18 kDa Translocator Protein (TSPO). Image data were collected between November 2017 and January 2020 (‘Pre-Pandemic’ cLBP) or between August 2020 and May 2022 (‘Pandemic’ cLBP). Compared to the Pre-Pandemic group, the Pandemic patients demonstrated widespread and statistically significant elevations in brain TSPO levels (P =.05, cluster corrected). PET signal elevations in the Pandemic group were also observed when 1) excluding 3 Pandemic subjects with a known history of COVID infection, or 2) using secondary outcome measures (volume of distribution -VT- and VT ratio - DVR) in a smaller subset of participants. Pandemic subjects also exhibited elevated serum levels of inflammatory markers (IL-16; P <.05) and estimated BA (P <.0001), which were positively correlated with [11C]PBR28 SUVR (r’s ≥ 0.35; P’s < 0.05). The pain interference scores, which were elevated in the Pandemic group (P <.05), were negatively correlated with [11C]PBR28 SUVR in the amygdala (r = −0.46; P<.05). This work suggests that the pandemic outbreak may have been accompanied by neuroinflammation and increased brain age in cLBP patients, as measured by multimodal imaging and serum testing. This study underscores the broad impact of the pandemic on human health, which extends beyond the morbidity solely mediated by the virus itself