Fast detector/first responder : interactions between the superior colliculus-pulvinar pathway and stimuli relevant to primates

Primates are distinguished from other mammals by their heavy reliance on the visual sense, which occurred as a result of natural selection continually favoring those individuals whose visual systems were more responsive to challenges in the natural world. Here we describe two independent but also interrelated visual systems, one cortical and the other subcortical, both of which have been modified and expanded in primates for different functions. Available evidence suggests that while the cortical visual system mainly functions to give primates the ability to assess and adjust to fluid social and ecological environments, the subcortical visual system appears to function as a rapid detector and first responder when time is of the essence, i.e., when survival requires very quick action. We focus here on the subcortical visual system with a review of behavioral and neurophysiological evidence that demonstrates its sensitivity to particular, often emotionally charged, ecological and social stimuli, i.e., snakes and fearful and aggressive facial expressions in conspecifics. We also review the literature on subcortical involvement during another, less emotional, situation that requires rapid detection and response—visually guided reaching and grasping during locomotion—to further emphasize our argument that the subcortical visual system evolved as a rapid detector/first responder, a function that remains in place today. Finally, we argue that investigating deficits in this subcortical system may provide greater understanding of Parkinson's disease and Autism Spectrum disorders (ASD)

Influence of Activation Parameters on the Mechanical and Microstructure Properties of an Alkali-Activated BOF Steel Slag

ABSTRACT: Steel slag (SS) is a secondary material from steelmaking production with little commercial value. Its volumetric expansion and low reactivity limit the use of SS in Portland cement (PC)- based materials. This study investigated the potential use of basic oxygen furnace (BOF) slag as a single precursor in alkali-activated matrices (AAMs). Six AAM pastes were assessed by changing the silica modulus (0.75, 1.50 and 2.22) and the sodium concentration (4% or 6% Na2O?wt. SS). The early hydration was assessed using isothermal calorimetry (IC), followed by the assessment of the mechanical performance (compressive strength), apparent porosity, and structure and microstructure characterization (X-ray diffraction, thermogravimetric analysis and scanning electron microscopy). The results indicated that although the BOF slag may be considered a low-reactivity material, the alkaline environment effectively dissolved important crystalline phases to produce hydrates (reaction products). An optimized combination of activator sources was achieved with 4% Na2O and a silica modulus of 1.50?2.22, with a compressive strength up to 20 MPa, a significant amount of reaction products (C-S-H/C-A-S-H gels), and low initial and cumulative heat release. Those properties will help to promote SS recycling use in future engineering projects that do not require high-strength materials.This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—finance code 001, grant PPM-00709-18 (FAPEMIG) and grant 316882/2021-6 (CNPq

VALIDATION OF A METHODOLOGY TO DEVELOP A TEST FACILITY IN REDUCED SCALE RELATED TO BORON DISPERSION IN A PRESSURIZER OF AN iPWR

The conception and the project of a 1:200 reduced scale test facility have been developed in earlier researches [1,2,3,4]. Such a facility aims to investigate boron homogenization process inside the pressurizer of an iPWR (integral PWR) by considering water mixing from this component with that coming from the reactor core. For this kind of reactor, the pressurizer is located at the top of the pressure vessel demanding the need of identifying the proper mechanisms in order to warrant an adequate homogenization for the water mixture. Once the installation of the experimental setup was concluded, its behavior has been analyzed by considering the concentration of a tracer diluted in the circulation water, whose measurements were obtained at the pressurizer outlet orifices. Two experiments representing boration(boron concentration increase)/deboration(boron concentration decrease) scenarios have been accomplished. Sample acquisition was carried out for every ten minutes during a total time equal to180 minutes. Results showed that the combination of Fractional Scaling Analysis with local Froude number consisted of an appropriate methodology to provide the reduced scale test facility parameters, inasmuch the measured concentrations from the experiments reproduced the theoretical behavior with sufficient accuracy

ADSORÇÃO DO CORANTE TÊXTIL AZUL REMAZOL POR PECÍOLO DE BURITI (Mauritia flexuosa L.f.)

No presente trabalho foi investigada a remoção do corante azul remazol usando como adsorvente o pecíolo do buriti. A partir do espectro de infravermelho, foram identificados os principais grupos funcionais do adsorvente. O comprimento de onda de máxima absorção (λmáx) do corante foi obtido por espectrofotometria na região do UV-visível foi 595nm. O pH no ponto de carga zero do adsorvente foi estimado graficamente em torno de 4,6. Foram investigados alguns parâmetros tais como: a influência do pH, o tempo de contato e a concentração do corante. A capacidade de adsorção do corante é maior em pH's mais baixos. Os modelos cinéticos de adsorção que apresentaram os melhores ajustes foram os de pseudossegunda ordem para a menor concentração (R2 ≈ 93%) e Elovich para as concentrações de 400 e 800 mg.L-1 (R2 ≈ 97%). Os modelos isotérmicos utilizados foram os de Freundlich, Sips e Multicamada. Os modelos de Sips e Multicamada foram os que ajustaram melhor os dados de equilíbrio (R2 > 96%). A quantidade máxima adsorvida estimada pelo modelo de Sips foi 33 mg.g-1. Essa capacidade de adsorção relativamente alta torna o pecíolo do buriti um adsorvente com potencial para remover corantes.Palavras-chave: Pecíolo de buriti (Mauritia flexuosa L.f.). Adsorção. Corantes têxteis.ADSORPTION OF BLUE TEXTILE DYE REMAZOL FOR BURITI PETIOLE (Mauritia flexuosa Lf)Abstract: In the present study was investigated the removal of Remazol Blue dye using as adsorbent buriti petiole. From the IR spectrum. the main functional groups of the adsorbent were identified. The wavelength of maximum absorption (λmáx) of the dye was obtained by spectrophotometric in the UV-visible was 595 nm. The pH at the point of zero charge of the adsorbent was estimated graphically at 4,6. Were investigated Some parameters were investigated such as: the influence of pH, the contact time and the concentration of the dye. The adsorption capacity of the dye is higher in lower pH's. The adsorption kinetic models that showed the best fits were the pseudo-second order for the lower concentration (R2 ≈ 93%) and Elovich for  concentrations of 400 and 800 mg.L-1 (R2 ≈ 97%). The isotherm models used were those of Freundlich, Sips and Multilayer. Sips and Multilayer models were best fitted the equilibrium data (R2 > 96%). The maximum amount adsorbed estimated by Sips model was 33 mg.g-1. That relatively high adsorption capacity makes the buriti petiole a potential adsorbent to remove dyes.Keywords: Buriti petiole (Mauritia flexuosa L.f.). Adsorption. Textile dyes.ADSORCIÓN DEL COLORANTE TEXTIL AZUL REMAZOL POR EL PECÍOLO DE BURITI (Mauritia flexuosa L.f.)Resumen: En el presente trabajo fue investigada la retirada del colorante azul remazol usando como adsorbente el peciolo del buriti. Através del espectro infrarrojo se identificaron los principales grupos funcionales del adsorbente. La longitud de onda de absorción máxima (λmáx ) del colorante se obtuvo por espectrofotometria en UV-Visible en 595nm. El pH en el punto de carga cero del adsorbente foi aproximado graficamente en 4,6. Fueron investigados la influencia del pH, tiempo de contacto y la concentración del colorante. La capacidade de adsorción del colorante es mayor en pH's mas bajos. Los modelos cinéticos de adsorción que presentaron los mejores ajustes fueron los de pseudo-segundo orden para la menor concentración (R2 ≈ 93%) e Elovich para las concentraciones de 400 y 800 mg.L-1 (R2 ≈ 97%). Los modelos isotérmicos utilizados fueron los de Freundlich, Sips y de Multicapas. Los modelos de Sips y de Multicapas fueron los que adecuaron mejor los datos del equilibrio (R2 > 96%). La cantidad máxima adsorbida calculada por el modelo de Sips fue de 33 mg.g-1. Esta capacidad relativamente alta de adsorción define al peciolo del buriti como un adsorbente con potencial para retirar colorantes.Keywords: Peciolo de buriti (Mauritia flexuosa L.f.). Adsorción. Colorantes téxtiles

Automated lumen segmentation using multi-frame convolutional neural networks in Intravascular Ultrasound datasets

Aims: Assessment of minimum lumen areas in intravascular ultrasound (IVUS) pullbacks is time-consuming and demands adequately trained personnel. In this work, we introduce a novel and fully automated pipeline to segment the lumen boundary in IVUS datasets. Methods and results First, an automated gating is applied to select end-diastolic frames and bypass saw-tooth artefacts. Second, within a machine learning (ML) environment, we automatically segment the lumen boundary using a multi-frame (MF) convolutional neural network (MFCNN). Finally, we use the theory of Gaussian processes (GPs) to regress the final lumen boundary. The dataset consisted of 85 IVUS pullbacks (52 patients). The dataset was partitioned at the pullback-level using 73 pullbacks for training (20 586 frames), 6 pullbacks for validation (1692 frames), and 6 for testing (1692 frames). The degree of overlapping, between the ground truth and ML contours, median (interquartile range, IQR) systematically increased from 0.896 (0.874–0.933) for MF1 to 0.925 (0.911–0.948) for MF11. The median (IQR) of the distance error was also reduced from 3.83 (2.94–4.98)% for MF1 to 3.02 (2.25–3.95)% for MF11-GP. The corresponding median (IQR) in the lumen area error remained between 5.49 (2.50–10.50)% for MF1 and 5.12 (2.15–9.00)% for MF11-GP. The dispersion in the relative distance and area errors consistently decreased as we increased the number of frames, and also when the GP regressor was coupled to the MFCNN output. Conclusion: These results demonstrate that the proposed ML approach is suitable to effectively segment the lumen boundary in IVUS scans, reducing the burden of costly and time-consuming manual delineation.Fil: Ziemer, Paulo G. P.. Laboratorio Nacional de Computacao Cientifica; BrasilFil: Bulant, Carlos Alberto. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Grupo de Plasmas Densos Magnetizados. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Grupo de Plasmas Densos Magnetizados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: Orlando, José Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Grupo de Plasmas Densos Magnetizados. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Grupo de Plasmas Densos Magnetizados; ArgentinaFil: Maso Talou, Gonzalo D.. University of Auckland; Nueva ZelandaFil: Mansilla Álvarez, Luis A.. Laboratorio Nacional de Computacao Cientifica; BrasilFil: Guedes Bezerra, Cristiano. Universidade de Sao Paulo; BrasilFil: Lemos, Pedro A.. Universidade de Sao Paulo; BrasilFil: García García, Héctor M.. Georgetown University School of Medicine; Estados UnidosFil: Blanco, Pablo J.. Laboratorio Nacional de Computacao Cientifica; Brasi

(2E)-N′-[(E)-4-Chloro­benzyl­idene]-3-phenyl­prop-2-enohydrazide monohydrate

The conformation about each of the imine and ethene bonds in the title hydrazide hydrate, C16H13ClN2O·H2O, is E. The hydrazide mol­ecule is approximately planar (r.m.s. deviation of the 20 non-H atoms = 0.172 Å). The most significant twist occurs about the ethene bond [C—C=C—C = 164.1 (5)°] and the dihedral angle formed between the benzene rings is 5.3 (2)°]. In the crystal, the presence of N—H⋯Ow and O—H⋯Oc (× 2; w = water and c = carbon­yl) hydrogen bonds leads to a supra­molecular array in the bc plane

Monkey pulvinar neurons fire differentially to snake postures

There is growing evidence from both behavioral and neurophysiological approaches that primates are able to rapidly discriminate visually between snakes and innocuous stimuli. Recent behavioral evidence suggests that primates are also able to discriminate the level of threat posed by snakes, by responding more intensely to a snake model poised to strike than to snake models in coiled or sinusoidal postures (Etting and Isbell 2014). In the present study, we examine the potential for an underlying neurological basis for this ability. Previous research indicated that the pulvinar is highly sensitive to snake images. We thus recorded pulvinar neurons in Japanese macaques (Macaca fuscata) while they viewed photos of snakes in striking and non-striking postures in a delayed non-matching to sample (DNMS) task. Of 821 neurons recorded, 78 visually responsive neurons were tested with the all snake images. We found that pulvinar neurons in the medial and dorsolateral pulvinar responded more strongly to snakes in threat displays poised to strike than snakes in non-threat-displaying postures with no significant difference in response latencies. A multidimensional scaling analysis of the 78 visually responsive neurons indicated that threat-displaying and non threatdisplaying snakes were separated into two different clusters in the first epoch of 50 ms after stimulus onset, suggesting bottom-up visual information processing. These results indicate that pulvinar neurons in primates discriminate between poised to strike from those in non-threat-displaying postures. This neuronal ability likely facilitates behavioral discrimination and has clear adaptive value. Our results are thus consistent with the Snake Detection Theory, which posits that snakes were instrumental in the evolution of primate visual systems

AdS and stabilized extra dimensions in multidimensional gravitational models with nonlinear scalar curvature terms 1/R and R^4

We study multidimensional gravitational models with scalar curvature nonlinearities of the type 1/R and R^4. It is assumed that the corresponding higher dimensional spacetime manifolds undergo a spontaneous compactification to manifolds with warped product structure. Special attention is paid to the stability of the extra-dimensional factor spaces. It is shown that for certain parameter regions the systems allow for a freezing stabilization of these spaces. In particular, we find for the 1/R model that configurations with stabilized extra dimensions do not provide a late-time acceleration (they are AdS), whereas the solution branch which allows for accelerated expansion (the dS branch) is incompatible with stabilized factor spaces. In the case of the R^4 model, we obtain that the stability region in parameter space depends on the total dimension D=dim(M) of the higher dimensional spacetime M. For D>8 the stability region consists of a single (absolutely stable) sector which is shielded from a conformal singularity (and an antigravity sector beyond it) by a potential barrier of infinite height and width. This sector is smoothly connected with the stability region of a curvature-linear model. For D<8 an additional (metastable) sector exists which is separated from the conformal singularity by a potential barrier of finite height and width so that systems in this sector are prone to collapse into the conformal singularity. This second sector is not smoothly connected with the first (absolutely stable) one. Several limiting cases and the possibility for inflation are discussed for the R^4 model.Comment: 28 pages, minor cosmetic improvements, Refs. added; to appear in Class. Quantum Gra