Response to comments on "Differential Sensitivity to Human Communication in Dogs, Wolves, and Human Infants."

The comments by Fiset and Marshall-Pescini et al. raise important methodological issues and propose alternative accounts for our finding of perseverative search errors in dogs. Not denying that attentional processes and local enhancement are involved in such object search tasks, we provide here new evidence and argue that dogs’ behavior is affected by a combination of factors, including specific susceptibility to human communicative signals

Review on the Removal of Metal Ions from Effluents Using Seaweeds, Alginate Derivatives and Other Sorbents

Biosorbents, especially those derived from seaweed (macroscopic algae) and alginate derivatives, exhibit high affinity for many metal ions. Because biosorbents are widely abundant (usually biodegradable) and less expensive than industrial synthetic adsorbents, they hold great potential for the removal of toxic metals from industrial effluents. Various studies have demonstrated the efficiency of living and non-living micro-organisms, such as bacteria, yeasts, moulds, micro-algae, cyanobacteria and biomass from water treatment sewage to remove metals from solution. Several types of organic and inorganic biomass have also been used as sorbent materials. In addition, by-products from the forestry industry, as well as agriculture waste and natural sorbents, have also been studied. This paper reviews and summarizes some key recent developments in these areas and it describes and discusses some specific applications of selected natural sorbents.Les biosorbants, particulièrement ceux préparés à partir des algues macroscopiques et des dérivés d’alginate, démontrent une très bonne capacité d’adsorption des ions métalliques toxiques. Ces biosorbants étant facilement disponibles (biodégradable) et moins coûteux que les adsorbants (industriels) synthétiques, ils présentent un grand potentiel d’utilisation pour l’enlèvement des métaux toxiques des effluents industriels. Les récents développements dans ce domaine ont été revus et font l’objet de la présente synthèse. Des applications spécifiques sont décrites et discutées.Diverses technologies sont disponibles pour enlever les métaux des effluents industriels tels que la précipitation (sous forme d’hydroxydes ou de sulfures), la coprécipitation, l’adsorption, l’extraction par solvant, la cémentation, l’électrodéposition, l’électrocoagulation, l’échange d’ions et les technologies de séparation membranaire. Néanmoins, la plupart de ces techniques présentent des coûts d’exploitation élevés et, dans certains cas, sont limitées en terme de rendement d’élimination des métaux. Dans ce contexte, l’utilisation d’adsorbants naturels (dérivés de matière organique ou inorganique) constitue une alternative intéressante aux produits synthétiques. De nombreux articles ont d’ailleurs été publiés au cours des dernières années faisant état de la performance d’une grande variété d’adsorbants naturels pour enlever les métaux des effluents.Plusieurs espèces d’algues marines ont aussi démontré des propriétés pour adsorber les métaux, mais les algues marines brunes, telles que Sargassum et Ascophyllum semblent avoir la plus grande capacité de rétention des métaux, à cause de leur grande concentration en polysaccharides. L’intégrité physique des algues est également importante, ceci afin de prévenir leur désintégration pendant les processus d’adsorption. Afin d’améliorer la stabilité et les propriétés mécaniques des algues fraîches, diverses méthodes ont été suggérées : i) greffage dans des polymères synthétiques; ii) incorporation dans des matériaux inorganiques; iii) liaison sur un support adéquat; et iv) séquestration par un agent de liaison.L’acide alginique est un polymère naturel se trouvant dans les algues brunes. Ce polymère est extrait en traitant les algues avec une solution de carbonate de sodium, puis l’acide alginique est précipité, ou converti en sel d’alginate de calcium. Lorsque l’acide alginique réagit avec des ions polyvalents, tel que le calcium, une séquestration se produit procurant un gel d’alginate ayant des forces structurales significatives. L’alginate de calcium peut être préparé sous plusieurs formes, telles que des billes, de la poudre, des membranes, des fibres ou des supports d’immobilisation cellulaire. Les billes sont particulièrement intéressantes du point de vue de leur application et de leur réutilisation.L’utilisation des algues marines en tant que procédé d’enlèvement des métaux doit tenir compte de plusieurs considérations techniques. Les systèmes de biosorption utilisent les biomasses sous forme solide en un procédé conventionnel de contact solide-liquide et, dans certains cas, les systèmes comprennent plusieurs étapes de biosorption et de désorption. L’effluent à traiter peut entrer en contact avec la biomasse selon un procédé en mode discontinu, semi-continu ou continu. Une fois saturés en métaux lourds, les adsorbants peuvent être disposés de façon sécuritaire, ou être réutilisés après élution des métaux. Dans ce cas, la plupart des métaux lourds (Cd, Co, Cu, Mn, Pb, Zn) peuvent être élués à l’aide d’acides dilués (chlorhydrique, sulfurique, nitrique) ou de solutions salines concentrées. Certains métaux qui sont moins dépendants du pH d’adsorption (Au, Ag, Hg) ne peuvent être élués en utilisant un acide dilué. Des solutions de thiourée ou de mercaptol peuvent être utilisées pour l’or et l’acétate de sodium pour la récupération de l’argent. La combustion des algues est également possible, néanmoins, elle n’est envisageable que si l’adsorbant est peu dispendieux et grandement disponible.Plusieurs types de biomasses organiques ou inorganiques peuvent être utilisés comme matériaux adsorbants. Des études ont démontré l’efficacité des microorganismes vivants ou morts incluant les bactéries, les levures, les moisissures, les microalgues, les cyanobactéries et les biomasses issues du traitement des eaux usées (boues d’épuration). Les rejets de l’industrie forestière, incluant les sciures et les écorces de bois riches en lignine et en tannins, ont été également étudiés de façon intensive. Certaines plantes aquatiques (Ceratophyllum demersum, Lemna minor, Myriophyllum spicatum) ont également été évaluées pour leur capacité en phytofiltration et phytoassainissement. D’autres études ont été effectuées sur la performance de fixation des métaux de la chitine, cette dernière étant un biopolymère naturel très abondant, lequel est classé second après la cellulose en terme d’abondance. Ce biopolymère se retrouve largement dans l’exosquelette des crustacés et des coquillages. Le chitosan est produit en effectuant la dé-acétylation de la chitine en milieu alcalin. La mousse de tourbe, les déchets d’agriculture (résidus de thé et de café, pelures de certains légumes, écailles de noix, d’arachides, de cacao) et divers autres adsorbants de nature inorganique (sable, argile, oxyde, zéolites) ont également été étudiés pour la récupération des métaux en solution.D’un point de vue économique, plusieurs méthodes existent pour traiter les eaux usées. La sélection d’une méthode dépend de plusieurs critères, tels que la compatibilité avec les opérations existantes, les coûts d’exploitation, la flexibilité des procédés afin de pouvoir traiter des variations de charges hydrauliques et de concentrations de contaminants. La méthode doit être aussi fiable, robuste et simple d’utilisation. Dans certains cas, des économies substantielles peuvent être réalisées en faisant appel à l’adsorption des métaux sur des biomasses, comparativement aux procédés conventionnels, tel que la précipitation des métaux

Regional cerebral blood flow changes as a function of delta and spindle activity during slow wave sleep in humans

In the present study, we investigated changes in regional cerebral blood flow (rCBF) in humans during the progression from relaxed wakefulness through slow wave sleep (SWS). These changes were examined as a function of spindle (12-15 Hz) and delta (1.5-4.0 Hz) electroencephalographic (EEG) activity of SWS. rCBF was studied with positron emission tomography (PET) using the H215O bolus method. A maximum of six 60 sec scans were performed per subject during periods of wakefulness and stages 1-4 of SWS, as determined by on-line EEG monitoring. Spectral analysis was performed off-line on the EEG epochs corresponding to the scans for computation of activity in specific frequency bands. The relationship between EEG frequency band activity and normalized rCBF was determined by means of a voxel-by-voxel analysis of covariance. delta activity covaried negatively with rCBF most markedly in the thalamus and also in the brainstem reticular formation, cerebellum, anterior cingulate, and orbitofrontal cortex. After the effect of delta was removed, a significant negative covariation between spindle activity and the residual rCBF was evident in the medial thalamus. These negative covariations may reflect the disfacilitation and active inhibition of thalamocortical relay neurons in association with delta and spindles, as well as the neural substrates underlying the progressive attenuation of sensory awareness, motor responsiveness, and arousal that occur during SWS. delta activity covaried positively with rCBF in the visual and auditory cortex, possibly reflecting processes of dream-like mentation purported to occur during SW

Reading between Eye Saccades

Background: Skilled adult readers, in contrast to beginners, show no or little increase in reading latencies as a function of the number of letters in words up to seven letters. The information extraction strategy underlying such efficiency in word identification is still largely unknown, and methods that allow tracking of the letter information extraction through time between eye saccades are needed to fully address this question. Methodology/Principal Findings: The present study examined the use of letter information during reading, by means of the Bubbles technique. Ten participants each read 5,000 five-letter French words sampled in space-time within a 200 ms window. On the temporal dimension, our results show that two moments are especially important during the information extraction process. On the spatial dimension, we found a bias for the upper half of words. We also show for the first time that letter positions four, one, and three are particularly important for the identification of five-letter words. Conclusions/Significance: Our findings are consistent with either a partially parallel reading strategy or an optimal serial reading strategy. We show using computer simulations that this serial reading strategy predicts an absence of a wordlength effect for words from four- to seven letters in length. We believe that the Bubbles technique will play an importan

Too little, too late: reduced visual span and speed characterize pure alexia

Whether normal word reading includes a stage of visual processing selectively dedicated to word or letter recognition is highly debated. Characterizing pure alexia, a seemingly selective disorder of reading, has been central to this debate. Two main theories claim either that 1) Pure alexia is caused by damage to a reading specific brain region in the left fusiform gyrus or 2) Pure alexia results from a general visual impairment that may particularly affect simultaneous processing of multiple items. We tested these competing theories in 4 patients with pure alexia using sensitive psychophysical measures and mathematical modeling. Recognition of single letters and digits in the central visual field was impaired in all patients. Visual apprehension span was also reduced for both letters and digits in all patients. The only cortical region lesioned across all 4 patients was the left fusiform gyrus, indicating that this region subserves a function broader than letter or word identification. We suggest that a seemingly pure disorder of reading can arise due to a general reduction of visual speed and span, and explain why this has a disproportionate impact on word reading while recognition of other visual stimuli are less obviously affected

Culture shapes how we look at faces

Background: Face processing, amongst many basic visual skills, is thought to be invariant across all humans. From as early as 1965, studies of eye movements have consistently revealed a systematic triangular sequence of fixations over the eyes and the mouth, suggesting that faces elicit a universal, biologically-determined information extraction pattern. Methodology/Principal Findings: Here we monitored the eye movements of Western Caucasian and East Asian observers while they learned, recognized, and categorized by race Western Caucasian and East Asian faces. Western Caucasian observers reproduced a scattered triangular pattern of fixations for faces of both races and across tasks. Contrary to intuition, East Asian observers focused more on the central region of the face. Conclusions/Significance: These results demonstrate that face processing can no longer be considered as arising from a universal series of perceptual events. The strategy employed to extract visual information from faces differs across cultures

Deuteron life-time in hot and dense nuclear matter near equilibrium

We consider deuteron formation in hot and dense nuclear matter close to equilibrium and evaluate the life-time of the deuteron fluctuations within the linear response theory. To this end we derive a generalized linear Boltzmann equation where the collision integral is related to equilibrium correlation functions. In this framework we then utilize finite temperature Green functions to evaluate the collision integrals. The elementary reaction cross section is evaluated within the Faddeev approach that is suitably modified to reflect the properties of the surrounding hot and dense matter.Comment: 15 pages, 5 figure

Letter processing and font information during reading: beyond distinctiveness, where vision meets design

Letter identification is a critical front end of the reading process. In general, conceptualizations of the identification process have emphasized arbitrary sets of distinctive features. However, a richer view of letter processing incorporates principles from the field of type design, including an emphasis on uniformities across letters within a font. The importance of uniformities is supported by a small body of research indicating that consistency of font increases letter identification efficiency. We review design concepts and the relevant literature, with the goal of stimulating further thinking about letter processing during reading

Anesthetic management of patients with class 3 obesity undergoing elective Cesarean delivery: a single-centre historical cohort study

PURPOSE: The preferred neuraxial anesthetic technique for patients with class 3 obesity undergoing elective Cesarean delivery is still under debate. We aimed to describe the anesthetic technique used in our tertiary institution across body mass index (BMI) groups and different surgical incisions. METHOD: In this historical cohort study, we reviewed medical records of patients with a BMI ≥ 40 kg·m-2 undergoing elective Cesarean delivery between July 2014 and December 2020. We collected data on patient characteristics, anesthetic and surgical technique, and procedural times. For data analysis, we stratified patients by BMI into three different groups: 40.0-49.9 kg·m-2, 50.0-59.9 kg·m-2, and ≥ 60.0 kg·m-2. RESULTS: We included 396 deliveries, distributed as follows: 258 with a BMI 40.0-49.9 kg·m-2, 112 with a BMI 50.0-59.9 kg·m-2, and 26 with a BMI ≥ 60.0 kg·m-2. For patients with a BMI 40.0-49.9 kg·m-2, the anesthetic technique of first choice was predominantly spinal anesthesia (71%), whereas for those with a BMI ≥ 60.0 kg·m-2, spinal anesthesia was never used as the anesthetic of first choice. With regard to the surgical incision, spinal anesthesia was almost exclusively used for patients undergoing Pfannenstiel incision and was rarely used for a higher supra- or infraumbilical transverse or midline incision. The overall incidence of general anesthesia was low (7/396, 1.8%). Anesthetic time, surgical time, and operating room time increased almost twofold in patients with a BMI ≥ 60.0 kg·m-2 compared with those with a BMI of 40.0-49.9 kg·m-2. CONCLUSION: Neuraxial anesthesia was successfully used in approximately 98% of patients with class 3 obesity undergoing elective Cesarean delivery. The choice of regional anesthesia technique varied with increasing BMI and with the planned surgical incision. Procedural times increased with increasing BMI. This information should prove useful for comparing anesthetic choices and outcomes in this challenging population