Limited information-processing capacity in vision explains number psychophysics.

Humans and other animals are able to perceive and represent a number of objects present in a scene, a core cognitive ability thought to underlie the development of mathematics. However, the perceptual mechanisms that underpin this capacity remain poorly understood. Here, we show that our visual sense of number derives from a visual system designed to efficiently encode the location of objects in scenes. Using a mathematical model, we demonstrate that an efficient but information-limited encoding of objects' locations can explain many key aspects of number psychophysics, including subitizing, Weber's law, underestimation, and effects of exposure time. In two experiments (N = 100 each), we find that this model of visual encoding captures human performance in both a change-localization task and a number estimation task. In a third experiment (N = 100), we find that individual differences in change-localization performance are highly predictive of differences in number estimation, both in terms of overall performance and inferred model parameters, with participants having numerically indistinguishable inferred information capacities across tasks. Our results therefore indicate that key psychophysical features of numerical cognition do not arise from separate modules or capacities specific to number, but rather as by-products of lower level constraints on perception. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Blue-shifted genetically encoded Ca2+ indicator with enhanced two-photon absorption.

Significance: Genetically encoded calcium ion (Ca2+) indicators (GECIs) are powerful tools for monitoring intracellular Ca2+ concentration changes in living cells and model organisms. In particular, GECIs have found particular utility for monitoring the transient increase of Ca2+ concentration that is associated with the neuronal action potential. However, the palette of highly optimized GECIs for imaging of neuronal activity remains relatively limited. Expanding the selection of available GECIs to include new colors and distinct photophysical properties could create new opportunities for in vitro and in vivo fluorescence imaging of neuronal activity. In particular, blue-shifted variants of GECIs are expected to have enhanced two-photon brightness, which would facilitate multiphoton microscopy. Aim: We describe the development and applications of T-GECO1-a high-performance blue-shifted GECI based on the Clavularia sp.-derived mTFP1. Approach: We use protein engineering and extensive directed evolution to develop T-GECO1. We characterize the purified protein and assess its performance in vitro using one-photon excitation in cultured rat hippocampal neurons, in vivo using one-photon excitation fiber photometry in mice, and ex vivo using two-photon Ca2+ imaging in hippocampal slices. Results: The Ca2+-bound state of T-GECO1 has an excitation peak maximum of 468 nm, an emission peak maximum of 500 nm, an extinction coefficient of 49,300 M-1 cm-1, a quantum yield of 0.83, and two-photon brightness approximately double that of EGFP. The Ca2+-dependent fluorescence increase is 15-fold, and the apparent Kd for Ca2+ is 82 nM. With two-photon excitation conditions at 850 nm, T-GECO1 consistently enabled the detection of action potentials with higher signal-to-noise (SNR) than a late generation GCaMP variant. Conclusions: T-GECO1 is a high-performance blue-shifted GECI that, under two-photon excitation conditions, provides advantages relative to late generation GCaMP variants.

Growth differentiation factor 11 suppresses intrahepatic inflammation via restricting NLRP3 inflammasome activation in LPS-induced liver injury.

Growth differentiation factor 11 (GDF11) is reported as a member of TGF-ß superfamily, which plays a key negative role in various tissue inflammation. However, the specific effect of GDF11 on infectious acute liver injury remains unknown. The current study is designed to certify the role of GDF11 both in LPS-induced RAW 264.7 cell line and rodent model of acute liver injury (ALI) and further investigate its molecular mechanism of inflammatory regulation. In vitro, LPS was used to stimulate the inflammatory activation of RAW 264.7 cells and then recombinant GDF11 (rGDF11) was used to treat the cells. In vivo, we injected LPS and rGDF11 in abdomen of mouse. The inflammatory indexes, GDF11 level, NLRP3 level, liver tissue injury, and liver function were examined using qRT-PCR, western blot, ELISA, IHC, IF and HE staining, respectively. Supplement of GDF11 protected the histology and function of liver tissue in LPS-induced ALI mice, in which the level of AST, ALT and TBiL associated with tissue damage were reduced after ALI. Moreover, increased GDF11 in RAW 264.7 cells and ALI mice reduced the expressions of COX-2, TNF-α, IL-1ß, and IL-6 via inhibiting NLRP3 inflammasome activation, suggesting the anti-inflammatory role of GDF11 in ALI. Besides, owing to the protective role of GDF11, the apoptotic degree in liver after LPS insult was attenuated, such as the reduced c-caspase-3 and annexin-V expressions. The results indicate that overexpression of GDF11 plays an antagonistic role in LPS-induced inflammatory response after ALI. Therefore, GDF11 may become a promising target for preventing infectious acute liver injury.

A blue-shifted genetically encoded Ca2+ indicator with enhanced two-photon absorption.

Significance: Genetically encoded calcium ion (Ca2+) indicators (GECIs) are powerful tools for monitoring intracellular Ca2+ concentration changes in living cells and model organisms. In particular, GECIs have found particular utility for monitoring the transient increase of Ca2+ concentration that is associated with the neuronal action potential. However, the palette of highly optimized GECIs for imaging of neuronal activity remains relatively limited. Expanding the selection of available GECIs to include new colors and distinct photophysical properties could create new opportunities for in vitro and in vivo fluorescence imaging of neuronal activity. In particular, blue-shifted variants of GECIs are expected to have enhanced two-photon brightness, which would facilitate multiphoton microscopy. Aim: We describe the development and applications of T-GECO1 - a high-performance blue-shifted GECI based on the Clavularia sp.-derived mTFP1. Approach: We used protein engineering and extensive directed evolution to develop T-GECO1. We characterize the purified protein and assess its performance in vitro using one-photon excitation in cultured rat hippocampal neurons, in vivo using one-photon excitation fiber photometry in mice, and ex vivo using two-photon Ca2+ imaging in hippocampal slices. Results: The Ca2+-bound state of T-GECO1 has an excitation peak maximum of 468 nm, an emission peak maximum of 500 nm, an extinction coefficient of 49,300 M-1cm-1, a quantum yield of 0.83, and two-photon brightness approximately double that of EGFP. The Ca2+-dependent fluorescence increase is 15-fold and the apparent Kd for Ca2+ is 82 nM. With two-photon excitation conditions at 850 nm, T-GECO1 consistently enabled detection of action potentials with higher signal-to-noise (SNR) than a late generation GCaMP variant. Conclusion: T-GECO1 is a high performance blue-shifted GECI that, under two-photon excitation conditions, provides advantages relative to late generation GCaMP variants.

Latent Diversity in Human Concepts.

Many social and legal conflicts hinge on semantic disagreements. Understanding the origins and implications of these disagreements necessitates novel methods for identifying and quantifying variation in semantic cognition between individuals. We collected conceptual similarity ratings and feature judgements from a variety of words in two domains. We analyzed this data using a non-parametric clustering scheme, as well as an ecological statistical estimator, in order to infer the number of different variants of common concepts that exist in the population. Our results show at least ten to thirty quantifiably different variants of word meanings exist for even common nouns. Further, people are unaware of this variation, and exhibit a strong bias to erroneously believe that other people share their semantics. This highlights conceptual factors that likely interfere with productive political and social discourse.

Biosensor Optimization Using a Förster Resonance Energy Transfer Pair Based on mScarlet Red Fluorescent Protein and an mScarlet-Derived Green Fluorescent Protein.

Genetically encoded biosensors based on Förster resonance energy transfer (FRET) are indispensable tools for monitoring biochemical changes in cells. Green and red fluorescent protein-based FRET pairs offer advantages over the classically employed cyan and yellow fluorescent protein pairs, such as better spectral separation, lower phototoxicity, and less autofluorescence. Here, we describe the development of an mScarlet-derived green fluorescent protein (designated as mWatermelon) and its use as a FRET donor to the red fluorescent protein mScarlet-I as a FRET acceptor. We tested the functionality of this FRET pair by engineering biosensors for the detection of protease activity, Ca2+, and K+. Furthermore, we described a strategy to enhance the FRET efficiency of these biosensors by modulating the intramolecular association between mWatermelon and mScarlet-I.

Complete genome sequence of piezotolerant Stutzerimonas kunmingensis 7850S isolated from the sediment of the Mariana Trench.

Stutzerimonas kunmingensis 7850S is a piezotolerant bacterium isolated from the sediment of the Mariana trench. Here, we described the complete genome of strain 7850S, which contains a single circular chromosome of 4,775,870 base pairs with 62.66% G + C content, and harbors 4494 protein-coding genes, 65 transfer RNA genes, and 12 ribosomal RNA genes. The experimental results showed that strain 7850S could grow under hydrostatic pressure of 0.1-70 MPa. Genomic analyses led to identifications of numbers of high hydrostatic pressure-associated genes, such as the ones associated with unsaturated fatty acids, betaine, and ectoine. A complete set of denitrification genes and some heavy metal detoxification genes were also found in this strain. The presence of these genes suggests metabolic characteristics for adaption to hadal environments and provides insights to further understand adaption strategies and ecological roles of Stutzerimonas in hadal environments.

Different grassland managements significantly change carbon fluxes in an alpine meadow.

Alpine meadow plays vital roles in regional animal husbandry and the ecological environment. However, different grassland managements affect the structure and function of the alpine meadow. In this study, we selected three typical grassland managements including free grazing, enclosure, and artificial grass planting and conducted a field survey to study the effects of grassland managements on carbon fluxes in an alpine meadow. The carbon fluxes were observed by static chamber and environmental factors including vegetation and soil characteristics were measured simultaneously. Our results show that the alpine meadow was a CO2 and CH4 sink, and grassland managements had a significant effect on all CO2 fluxes, including gross ecosystem production (GEP, P< 0.001), net ecosystem production (NEP, P< 0.001) and ecosystem respiration (ER, P< 0.001) but had no significant effect on CH4 fluxes (P > 0.05). The ranking of GEP under the different grassland managements was enclosure > free grazing > artificial grass planting. Furthermore, NEP and ER at enclosure plots were significantly higher than those of the free grazing and artificial grass planting plots. In addition, different grassland managements also affected the vegetation and soil characteristics of the alpine meadow. The aboveground biomass of artificial grass planting was significantly higher than that of the free grazing and enclosure plots. The vegetation coverage under three different grassland managements was ranked in the order of enclosure > artificial grass planting > free grazing and significant differences were observed among them. Moreover, significant differences in the number of species (P< 0.01) and the Margalef richness index (P< 0.05) were detected under three different grassland managements. Further analysis of the relationship between environmental factors and carbon fluxes revealed that GEP and NEP of the alpine meadow were positively correlated with vegetation coverage, the number of species, and the Margalef richness index. Therefore, grassland restoration should be configured with multiple species, which could improve carbon sink capacity while considering the functions of grassland restoration and production.

A sensitive and specific genetically-encoded potassium ion biosensor for in vivo applications across the tree of life.

Potassium ion (K+) plays a critical role as an essential electrolyte in all biological systems. Genetically-encoded fluorescent K+ biosensors are promising tools to further improve our understanding of K+-dependent processes under normal and pathological conditions. Here, we report the crystal structure of a previously reported genetically-encoded fluorescent K+ biosensor, GINKO1, in the K+-bound state. Using structure-guided optimization and directed evolution, we have engineered an improved K+ biosensor, designated GINKO2, with higher sensitivity and specificity. We have demonstrated the utility of GINKO2 for in vivo detection and imaging of K+ dynamics in multiple model organisms, including bacteria, plants, and mice.

Macaques preferentially attend to intermediately surprising information.

Normative learning theories dictate that we should preferentially attend to informative sources, but only up to the point that our limited learning systems can process their content. Humans, including infants, show this predicted strategic deployment of attention. Here, we demonstrate that rhesus monkeys, much like humans, attend to events of moderate surprisingness over both more and less surprising events. They do this in the absence of any specific goal or contingent reward, indicating that the behavioural pattern is spontaneous. We suggest this U-shaped attentional preference represents an evolutionarily preserved strategy for guiding intelligent organisms toward material that is maximally useful for learning.

The Effectiveness of Teacher Support for Students' Learning of Artificial Intelligence Popular Science Activities.

The burgeoning of new technologies is increasingly affecting people's lives. One new technology that is heatedly discussed is artificial intelligence (AI) in education. To allow students to understand the impact of emerging technologies on people's future lives from a young age, some popular science activities are being progressively introduced into elementary school curricula. Popular science activities are informal education programs and practices of universal education. However, two issues need to be discussed in the implementation of these activities. First, because these informal curricula are usually short in duration, the question of whether they only serve to generate motivation or actually enhance learning outcomes requires examination. Second, the role of teacher support in popular science activities and its impact on students' learning results need to be further investigated. To this end, this study aims to explore the effectiveness of popular AI science activities in informal curricula on students' AI achievement and the interrelationship between students' learning outcomes in popular AI science activities with and without teacher support. A 6-h-long AI popular science activity was conducted with 22 fifth- and sixth-grade students in elementary school. This study was conducted using a one-group pretest and posttest design, and the data collection tools included AI achievement pre- and posttests and an artifact scoring rubric. The results showed that with regard to learning outcomes, popular science activities were helpful for cognitive enhancement of AI concepts, but more time was needed for skills to improve. Additionally, this study found that students' learning performance was different with and without teacher support. Activities with teacher support can enhance students' learning outcomes, but students become accustomed to relying on their teachers. In contrast, activities without teacher support seem to be more effective in fostering students' independent computational thinking and problem-solving abilities.

Fluorescent Indicators For Biological Imaging of Monatomic Ions.

Monatomic ions play critical biological roles including maintaining the cellular osmotic pressure, transmitting signals, and catalyzing redox reactions as cofactors in enzymes. The ability to visualize monatomic ion concentration, and dynamic changes in the concentration, is essential to understanding their many biological functions. A growing number of genetically encodable and synthetic indicators enable the visualization and detection of monatomic ions in biological systems. With this review, we aim to provide a survey of the current landscape of reported indicators. We hope this review will be a useful guide to researchers who are interested in using indicators for biological applications and to tool developers seeking opportunities to create new and improved indicators.

Applying data mining techniques to explore user behaviors and watching video patterns in converged IT environments.

Comfortable leisure and entertainment is expected through multimedia. Web multimedia systems provide diversified multimedia interactions, for example, sharing knowledge, experience and information, and establishing common watching habits. People use information technology (IT) systems to watch multimedia videos and to perform interactive functions. Moreover, IT systems enhance multimedia interactions between users. To explore user behaviors in viewing multimedia videos by key points in time, multimedia video watching patterns are analyzed by data mining techniques. Data mining methods were used to analyze users' video watching patterns in converged IT environments. After the experiment, we recorded the processes of clicking the Web multimedia video player. The system logs of using the video player are classified into four variables, playing time, active playing time, played amount, and actively played amount. To explore the four variables, we apply the k-means clustering technique to organize the similar playing behavior patterns of the users into three categories: actively engaged users, watching engaged users, and long engaged users. Finally, we applied statistical analysis methods to compare the three categories of users' watching behaviors. The results showed that there were significant differences among the three categories.

Discourse Prosody in Children's Rhyme Speech Produced by Prelingually Deaf Mandarin-Speaking Children With Cochlear Implants.

Purpose This study aimed to obtain a comprehensive understanding about how Mandarin-speaking children with cochlear implants (CIs) performed speech prosody in a connected discourse and to what extent their prosodic scenario differed from those normal-hearing (NH) peers. Method Fifteen prelingually deaf Mandarin-speaking children with unilateral multichannel CIs were chosen and 15 age-matched NH controls were recruited. Speech samples were spontaneously elicited by children's rhyme speech genre and subject to phonetic annotation. Acoustic analysis was conducted on all speech samples, mainly focusing on the measurements of duration and fundamental frequency (F0). Tempo measures included temporal fluency, syllable-lengthening, and rhythm metrics, whereas melodic measures included both local and global F0 variations under different prosodic domains. Results The CI children generally achieved compatible temporal performance with the NH children in spontaneous discourse, except that they were somewhat arbitrary when operationalizing lengthening strategy and pausing strategy at different prosodic boundaries. With regard to melodic performance, CI children may not sufficiently modulate local phonetic nuances of F0 variation, and meanwhile, they performed atypically in the global F0 declination pattern and overall F0 resetting pattern, failing to signal the specific structure of children's rhyme discourse. Early age at implantation and longer CI experience did not play a significant role in the temporal performance of the CI children but did facilitate their articulation of dynamic pitch variation in the spontaneous discourse to some extent. Conclusion CI children did exhibit atypical prosodic patterns in discourse context, especially the overall mapping between the prosodic manifestation and the discourse structure.

Genetically encoded fluorescent indicators for imaging intracellular potassium ion concentration.

Potassium ion (K+) homeostasis and dynamics play critical roles in biological activities. Here we describe three genetically encoded K+ indicators. KIRIN1 (potassium (K) ion ratiometric indicator) and KIRIN1-GR are Förster resonance energy transfer (FRET)-based indicators with a bacterial K+ binding protein (Kbp) inserting between the fluorescent protein FRET pairs mCerulean3/cp173Venus and Clover/mRuby2, respectively. GINKO1 (green indicator of K+ for optical imaging) is a single fluorescent protein-based K+ indicator constructed by insertion of Kbp into enhanced green fluorescent protein (EGFP). These indicators are suitable for detecting K+ at physiologically relevant concentrations in vitro and in cells. KIRIN1 enabled imaging of cytosolic K+ depletion in live cells and K+ efflux and reuptake in cultured neurons. GINKO1, in conjunction with red fluorescent Ca2+ indicator, enable dual-color imaging of K+ and Ca2+ dynamics in neurons and glial cells. These results demonstrate that KIRIN1 and GINKO1 are useful tools for imaging intracellular K+ dynamics.

Monomerization of far-red fluorescent proteins.

Anthozoa-class red fluorescent proteins (RFPs) are frequently used as biological markers, with far-red (λem ∼ 600-700 nm) emitting variants sought for whole-animal imaging because biological tissues are more permeable to light in this range. A barrier to the use of naturally occurring RFP variants as molecular markers is that all are tetrameric, which is not ideal for cell biological applications. Efforts to engineer monomeric RFPs have typically produced dimmer and blue-shifted variants because the chromophore is sensitive to small structural perturbations. In fact, despite much effort, only four native RFPs have been successfully monomerized, leaving the majority of RFP biodiversity untapped in biomarker development. Here we report the generation of monomeric variants of HcRed and mCardinal, both far-red dimers, and describe a comprehensive methodology for the monomerization of red-shifted oligomeric RFPs. Among the resultant variants is mKelly1 (emission maximum, λem = 656 nm), which, along with the recently reported mGarnet2 [Matela G, et al. (2017) Chem Commun (Camb) 53:979-982], forms a class of bright, monomeric, far-red FPs.

Pyranopterin Coordination Controls Molybdenum Electrochemistry in Escherichia coli Nitrate Reductase.

We test the hypothesis that pyranopterin (PPT) coordination plays a critical role in defining molybdenum active site redox chemistry and reactivity in the mononuclear molybdoenzymes. The molybdenum atom of Escherichia coli nitrate reductase A (NarGHI) is coordinated by two PPT-dithiolene chelates that are defined as proximal and distal based on their proximity to a [4Fe-4S] cluster known as FS0. We examined variants of two sets of residues involved in PPT coordination: (i) those interacting directly or indirectly with the pyran oxygen of the bicyclic distal PPT (NarG-Ser(719), NarG-His(1163), and NarG-His(1184)); and (ii) those involved in bridging the two PPTs and stabilizing the oxidation state of the proximal PPT (NarG-His(1092) and NarG-His(1098)). A S719A variant has essentially no effect on the overall Mo(VI/IV) reduction potential, whereas the H1163A and H1184A variants elicit large effects (ΔEm values of -88 and -36 mV, respectively). Ala variants of His(1092) and His(1098) also elicit large ΔEm values of -143 and -101 mV, respectively. An Arg variant of His(1092) elicits a small ΔEm of +18 mV on the Mo(VI/IV) reduction potential. There is a linear correlation between the molybdenum Em value and both enzyme activity and the ability to support anaerobic respiratory growth on nitrate. These data support a non-innocent role for the PPT moieties in controlling active site metal redox chemistry and catalysis.