Search

In the presence of moving visual stimuli, the majority of animals follow the Fourier motion energy (luminance), independently of other stimulus features (edges, contrast, etc.). While the behavioral response to Fourier motion has been studied in the past, how Fourier motion is represented and processed by sensory brain areas remains elusive. Here, we investigated how visual moving stimuli with or without the first Fourier component (square-wave signal or missing fundamental signal) are represented in the main visual regions of the zebrafish brain. First, we monitored the larva's optokinetic response (OKR) induced by square-wave and missing fundamental signals. Then, we used two-photon microscopy and GCaMP6f zebrafish larvae to monitor neuronal circuit dynamics in the optic tectum and the pretectum. We observed that both the optic tectum and the pretectum circuits responded to the square-wave gratings. However, only the pretectum responded specifically to the direction of the missing-fundamental signal. In addition, a group of neurons in the pretectum responded to the direction of the behavioral output (OKR), independently of the type of stimulus presented. Our results suggest that the optic tectum responds to the different features of the stimulus (e.g., contrast, spatial frequency, direction, etc.), but does not respond to the direction of motion if the motion information is not coherent (e.g., the luminance and the edges and contrast in the missing-fundamental signal). On the other hand, the pretectum mainly responds to the motion of the stimulus based on the Fourier energy.

The aluminum to alkaline earth ratio (Al:[AE]) in borosilicate glass is introduced as a novel compositional parameter to produce high index waveguides through femtosecond laser inscription. Alkaline earths are considered to be major refractive index providers for laser written optical waveguides due to their collective migration toward the guiding region. Contrary to the existing belief that increasing the concentration of such index providers within a glass composition will help to produce high index change waveguides, we demonstrate that high index waveguides can be fabricated by tuning the Al:[AE] ratio while keeping the absolute concentration of the index provider to a minimum.

Submarine landslides can generate complicated patterns of seafloor relief that influence subsequent flow behaviour and sediment dispersal patterns. In subsurface studies, the term mass transport deposits (MTDs) is commonly used and covers a range of processes and resultant deposits. While the large-scale morphology of submarine landslide deposits can be resolved in seismic reflection data, the nature of their upper surface and its impact on both facies distributions and stratal architecture of overlying deposits is rarely resolvable. However, field-based studies often allow a more detailed characterisation of the deposit. The early post-rift Middle Jurassic deep-water succession of the Los Molles Formation is exceptionally well-exposed along a dip-orientated WSW-ENE outcrop belt in the Chacay Melehue depocentre, Neuquén Basin, Argentina. We correlate 27 sedimentary logs constrained by marker beds to document the sedimentology and architecture of a >47 m thick and at least 9.6 km long debrite, which contains two different types of megaclasts. The debrite overlies ramps and steps, indicating erosion and substrate entrainment. Two distinct sandstone-dominated units overlie the debrite. The lower sandstone unit is characterised by: 1) abrupt thickness changes, wedging and progressive rotation of laminae in sandstone beds associated with growth strata; and 2) detached sandstone load balls within the underlying debrite. The combination of these features suggests syn-sedimentary foundering processes due to density instabilities at the top of the fluid-saturated mud-rich debrite. The debrite relief controlled the spatial distribution of foundered sandstones. The upper sandstone unit is characterised by thin-bedded deposits, locally overlain by medium-to thick-bedded lobe axis/off-axis deposits. The thin-beds show local thinning and onlapping onto the debrite, where it develops its highest relief. Facies distributions and stacking patterns record the progradation of submarine lobes and their complex interaction with long-lived debrite-related topography. The emplacement of a kilometre-scale debrite in an otherwise mud-rich basinal setting and accumulation of overlying sand-rich deposits suggests a genetic link between the mass-wasting event and transient coarse clastic sediment supply to an otherwise sand-starved part of the basin. Therefore, submarine landslides demonstrably impact the routing and behaviour of subsequent sediment gravity flows, which must be considered when predicting facies distributions and palaeoenvironments above MTDs in subsurface datasets.

In order to prevent the propagation of human diseases transmitted by mosquitoes (as dengue or zika), a solution is to release mosquitoes infected by Wolbachia. In this study, we model the release and the propagation over time and space of such infected mosquitoes in a population of uninfected ones. The aim of this study is to investigate the best location in space of the release to ensure invasion by the infected mosquitoes.

Inherited rift topography controls the sediment routing, timing of sand supply, and sedimentary linkage of early post‐rift depocentres. Exhumed examples of early post‐rift turbidite systems are rare and previous studies have examined the evolution of individual depocentres; in contrast, the detailed evolution of early post‐rift turbidite systems across multiple depocentres has never been documented. Current fill‐and‐spill models do not detail the stratigraphic architecture and evolution of sedimentological characteristics of multiple intraslope fans developed across topography, including bed type distributions. Here, the evolution of three intraslope fans that developed across two early post‐rift depocentres is documented along an 18 km long transect in the southern Neuquén Basin, Argentina. The relative chronology of sand supply in depocentres is constrained with new U–Pb ages, and sediment source areas with provenance analysis. The early post‐rift intraslope fans record progradation of the system and progressive sedimentary linkage of post‐rift depocentres, transverse to local syn‐rift structures, with sediment routing subparallel to the cratonic basin margin. The large‐scale stratigraphic architecture of intraslope fans indicates an evolution as a fill‐and‐spill system, with initial confinement through flow stripping and overspill to spillover with erosion and bypass across a transverse topographic high separating the depocentres. Changes in early post‐rift intraslope fan characteristics, including thickness, sandstone content, lobe complex stacking patterns, stratal termination patterns and bed type distribution, record changing confinement through time within a depocentre, and spatially across depocentres. The strong spatial and vertical stratigraphic variability of transitional flow deposits and hybrid event beds reflects enhanced erosion, sediment bypass and flow transformation across transverse relief between the two depocentres during the spillover phase. These findings advance current understanding of early post‐rift turbidite systems and refine fill‐and‐spill models, which will help the prediction of spatial and vertical changes in rock quality and connectivity in subsurface hydrocarbon reservoirs and CO2 storage sites. [ABSTRACT FROM AUTHOR]

Gabon has a rich flora, many species of which are used in traditional medicine. However, little research has been carried out on this wealth. An ethnopharmacological survey in the Fang language was carried out among traditional practitioners to collect antimicrobial medicinal plants. Phytochemical profiling of ethanolic and methanolic extracts from Erismadelphus exsul Mildbr leaves was carried out using HPLC-ESI-Q/TOF and a molecular network approach. Antibacterial activity was assessed with disk diffusion and microdilution methods, antioxidant activity via DPPH and FRAP methods, and in vitro cell viability via Cell Counting Kit-8. A total of 21 medicinal plants were collected, grouped into 10 families, of which the Fabaceae is the most represented. Erismadelphus exsul was chosen for chemical and biological studies due to its citation frequency (RCF = 0.59) and the absence of previous phytochemical studies. These studies revealed 4 major families of natural compounds and annotated 19 compounds for the first time. The crude leaf extract showed significant antioxidant and antibacterial activity. Cytotoxicity studies showed that the leaves were not cytotoxic, unlike the bark. This study underlines the importance of preserving the ancestral knowledge of the Fang populations, while showing promising results for Erismadelphus exsul. [ABSTRACT FROM AUTHOR]

Associated minerals such as chrysocolla in ores, makes it difficult to extract soluble copper efficiently. This work analyzed samples of mixed copper minerals, varying the doses of reagents in flotation tests to maximize the extraction of soluble copper at La Bonita mining unit, in Arequipa, Peru. It was found that the lower chrysocolla content, the recovery of soluble copper increases significantly. Results allow strategies to be established focused on ore selection and mixing for reducing chrysocolla levels, releasing soluble copper minerals and improving their buoyancy. [ABSTRACT FROM AUTHOR]

Introduction: Healthcare workers continue to be a population at risk of vaccine-preventable diseases. The overall aim of our study was to contribute to the prevention of vaccine-preventable diseases among healthcare workers in Abidjan university teaching hospitals. Material and methods: A descriptive cross-sectional study was conducted over a 6-month period among healthcare workers in Abidjan's university teaching hospitals. Data were collected using two survey forms sent to the staff and management of the university hospitals. The data were processed using Epi info 7 software. Results: One thousand seventeen (1017) workers out of a population of 2550 participated in the study: 54.6% were women with an average age of 36 ± 6 years. They were represented by physicians in 47.7% of cases and had an average professional seniority of 7 ± 5 years. Coverage rates by infectious agent were: 53.1% (hepatitis B), 16.5% (influenza), 67.9% (tetanus), 46.6% (typhoid fever), 78.5% (yellow fever), 47.6% (meningitis). Most of the vaccination costs were covered by the caregivers themselves. Conclusion: The study of vaccination coverage among UHC nursing staff revealed low levels overall. A vaccination policy needs to be put in place. [ABSTRACT FROM AUTHOR]