296 research outputs found

    Tool-Use Training in a Species of Rodent: The Emergence of an Optimal Motor Strategy and Functional Understanding

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    Tool use is defined as the manipulation of an inanimate object to change the position or form of a separate object. The expansion of cognitive niches and tool-use capabilities probably stimulated each other in hominid evolution. To understand the causes of cognitive expansion in humans, we need to know the behavioral and neural basis of tool use. Although a wide range of animals exhibit tool use in nature, most studies have focused on primates and birds on behavioral or psychological levels and did not directly address questions of which neural modifications contributed to the emergence of tool use. To investigate such questions, an animal model suitable for cellular and molecular manipulations is needed.) to use a rake-like tool with their forelimbs to retrieve otherwise out-of-reach rewards. Eventually, they mastered effective use of the tool, moving it in an elegant trajectory. After the degus were well trained, probe tests that examined whether they showed functional understanding of the tool were performed. Degus did not hesitate to use tools of different size, colors, and shapes, but were reluctant to use the tool with a raised nonfunctional blade. Thus, degus understood the functional and physical properties of the tool after extensive training.Our findings suggest that tool use is not a specific faculty resulting from higher intelligence, but is a specific combination of more general cognitive faculties. Studying the brains and behaviors of trained rodents can provide insights into how higher cognitive functions might be broken down into more general faculties, and also what cellular and molecular mechanisms are involved in the emergence of such cognitive functions

    Trauma exposure and factors associated with ICD-11 PTSD and complex PTSD in adolescence: a cross-cultural study in Japan and Lithuania

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    Aims: Cross-cultural studies of posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD) based on ICD-11 diagnostic criteria are scarce, especially in adolescence. The study aimed to evaluate the trauma exposure, prevalence and factors associated with PTSD and CPTSD in general populations of adolescents in Lithuania and Japan. Methods: The study sample comprised 1746 adolescents from Lithuania (n = 832) and Japan (n = 914), 49.8% female. The mean age of study participants was 15.52 (S.D. = 1.64), ranging from 12 to 18 years. ICD-11 posttraumatic disorders were assessed using the International Trauma Questionnaire – Child and Adolescent version (ITQ-CA). Results: More than half of the adolescents in a total sample (61.5%) reported exposure to at least one traumatic event in their lifetime, 80.0% in Lithuania and 44.6% in Japan, with a higher prevalence of interpersonal trauma in Lithuania and more natural disaster exposure in Japan. The prevalence of PTSD was 5.2% (95% CI 3.8–6.9%) and 2.3% (95% CI 1.4–3.5%), CPTSD 12.3% (95% CI 10.1–14.7%) and 4.1% (95% CI 2.9–5.5%) in Lithuanian and Japanese samples, respectively. Cumulative trauma exposure, female gender, loneliness and financial difficulties in family predicted both PTSD and CPTSD in the total sample. Loneliness discriminated CPTSD v. PTSD in both Lithuanian and Japanese samples. Conclusions: This cross-cultural study is among the first which reported different patterns of trauma exposure in Asian Japanese and Lithuanian adolescents in Europe. Despite differences in trauma exposure and PTSD/CPTSD prevalence, we found similar predictors in both studies, particularly the importance of cumulative trauma exposure for PTSD/CPTSD, and social interpersonal factors for the risk of CPTSD. The study supports the universality of traumatic stress reactions to adverse life experiences in adolescence across cultures and regions and highlights different levels of traumatisation of adolescents in various countries

    Electron transport properties in Nb and NbN cluster-assembled films produced by a plasma-gas-condensation cluster source

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    Nb and NbN cluster-assembled films were produced by a plasma-gas-condensation cluster deposition apparatus and examined by transmission electron microscopy, electrical resistivity, and ultraviolet photoemission spectroscopy. The electron diffraction patterns of the Nb and NbN clusters displayed body-centered-cubic and NaCl-type diffraction rings, respectively. The electrical sheet resistance, R-square, of both Nb and NbN cluster-assembled films, however, showed no superconductivity down to 2 K. We found a linear relation in the log R-square versus T-1/4 plot for the Nb cluster assembly, suggesting an electron localization effect. For the NbN cluster-assembly, on the other hand, R-square showed a semiconductor type temperature dependence, which is consistent with the valence electron spectra. (C) 2003 American Institute of Physics

    Thermal Infrared Imaging Experiments of C-Type Asteroid 162173 Ryugu on Hayabusa2

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    The thermal infrared imager TIR onboard Hayabusa2 has been developed to investigate thermo-physical properties of C-type, near-Earth asteroid 162173 Ryugu. TIR is one of the remote science instruments on Hayabusa2 designed to understand the nature of a volatile-rich solar system small body, but it also has significant mission objectives to provide information on surface physical properties and conditions for sampling site selection as well as the assessment of safe landing operations. TIR is based on a two-dimensional uncooled micro-bolometer array inherited from the Longwave Infrared Camera LIR on Akatsuki (Fukuhara et al., 2011). TIR takes images of thermal infrared emission in 8 to 12 μm with a field of view of 16×12∘ and a spatial resolution of 0.05∘ per pixel. TIR covers the temperature range from 150 to 460 K, including the well calibrated range from 230 to 420 K. Temperature accuracy is within 2 K or better for summed images, and the relative accuracy or noise equivalent temperature difference (NETD) at each of pixels is 0.4 K or lower for the well-calibrated temperature range. TIR takes a couple of images with shutter open and closed, the corresponding dark frame, and provides a true thermal image by dark frame subtraction. Data processing involves summation of multiple images, image processing including the StarPixel compression (Hihara et al., 2014), and transfer to the data recorder in the spacecraft digital electronics (DE). We report the scientific and mission objectives of TIR, the requirements and constraints for the instrument specifications, the designed instrumentation and the pre-flight and in-flight performances of TIR, as well as its observation plan during the Hayabusa2 mission

    Dynamic Social Adaptation of Motion-Related Neurons in Primate Parietal Cortex

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    Social brain function, which allows us to adapt our behavior to social context, is poorly understood at the single-cell level due largely to technical limitations. But the questions involved are vital: How do neurons recognize and modulate their activity in response to social context? To probe the mechanisms involved, we developed a novel recording technique, called multi-dimensional recording, and applied it simultaneously in the left parietal cortices of two monkeys while they shared a common social space. When the monkeys sat near each other but did not interact, each monkey's parietal activity showed robust response preference to action by his own right arm and almost no response to action by the other's arm. But the preference was broken if social conflict emerged between the monkeys—specifically, if both were able to reach for the same food item placed on the table between them. Under these circumstances, parietal neurons started to show complex combinatorial responses to motion of self and other. Parietal cortex adapted its response properties in the social context by discarding and recruiting different neural populations. Our results suggest that parietal neurons can recognize social events in the environment linked with current social context and form part of a larger social brain network

    Transcriptomes of the Anther Sporophyte: Availability and Uses

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    An anther includes sporophytic tissues of three outer cell layers and an innermost layer, the tapetum, which encloses a locule where the gametophytic microspores mature to become pollen. The sporophytic tissues also comprise some vascular cells and specialized cells of the stomium aligning the long anther axis for anther dehiscence. Studies of the anther sporophytic cells, especially the tapetum, have recently expanded from the use of microscopy to molecular biology and transcriptomes. The available sequencing technologies, plus the use of laser microdissection and in silico subtraction, have produced high-quality anther sporophyte transcriptomes of rice, Arabidopsis and maize. These transcriptomes have been used for research discoveries and have potential for future discoveries in diverse areas, including developmental gene activity networking and changes in enzyme and metabolic domains, prediction of protein functions by quantity, secretion, antisense transcript regulation, small RNAs and promoters for generating male sterility. We anticipate that these studies with rice and other transcriptomes will expand to encompass other plants, whose genomes will be sequenced soon, with ever-advancing sequencing technologies. In comprehensive gene activity profiling of the anther sporophyte, studies involving transcriptomes will spearhead investigation of the downstream gene activity with proteomics and metabolomics

    Identification of Substrain-Specific Mutations by Massively Parallel Whole-Genome Resequencing of Synechocystis sp. PCC 6803

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    The cyanobacterium, Synechocystis sp. PCC 6803, was the first photosynthetic organism whose genome sequence was determined in 1996 (Kazusa strain). It thus plays an important role in basic research on the mechanism, evolution, and molecular genetics of the photosynthetic machinery. There are many substrains or laboratory strains derived from the original Berkeley strain including glucose-tolerant (GT) strains. To establish reliable genomic sequence data of this cyanobacterium, we performed resequencing of the genomes of three substrains (GT-I, PCC-P, and PCC-N) and compared the data obtained with those of the original Kazusa strain stored in the public database. We found that each substrain has sequence differences some of which are likely to reflect specific mutations that may contribute to its altered phenotype. Our resequence data of the PCC substrains along with the proposed corrections/refinements of the sequence data for the Kazusa strain and its derivatives are expected to contribute to investigations of the evolutionary events in the photosynthetic and related systems that have occurred in Synechocystis as well as in other cyanobacteria

    Experimental Correlation of Combined Heat and Mass Transfer for NH 3 -H 2 0 falling film absorption

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    vection. The main conclusion from this study is that the negative concentration gradient of the surface tension is a trigger for inducement of Marangoni convection before the additive solubility, while the imbalance of the surface tension and the interfacial tension is a trigger after the solubility limit. Acknowledgment The authors thank Mr. K. Iizuka, Tokyo University of Agriculture and Technology, for his experimental assistance. The authors acknowledge that this work has been partially funded by the Japan Science and Technology Corporation (JST). References Beutler, A., Greiter, I., Wagner, A., Hohhmann, L., Schreier, S., and Alefeld, G., 1996, "Surfactants and Fluid Properties," Int. J. Refrigeration, Vol. 19, No. 5, pp. 342-346. Chavepeyer, G" Salajan, M., Platten, J. K., and Smet, P., 1995, "InterfacialTension and Surface Adsorption in j-Heptanol/Water Systems," Journal of Colloid and Interface Science, Vol. 174, Daiguji, H,, Hihara, E., and Saito, T., 1997, "Mechanism of Absorption Enhancement by Surfactant," Int. J. Heat and Mass Transfer, Vol. 40, No. 8, pp. 1743-1752. Fujita, T., 1993, "Falling Liquid Films in Absorption Machines," Int. J. Refrigeration, Vol. 16, No. 4, pp. 282-294. Hihara, E" and Saito, T., 1993 Journal of Heat Transfer TL = temperature of the fluid far away from the plate t' = time t R = reference time u = velocity of the fluid UD = reference velocity at' = frequency X,, = distance of the transition point from the leading edge |3 = coefficient of volume expansion p = density e = amplitude (constant) 9 = nondimensional temperature u = nondimensional velocity i = y-i Introduction Transient laminar-free convection flow past an infinite vertical plate under different plate conditions was studied by many researchers. The first closed-form solutions for Prandtl number Pr = 1.0 in case of a step change in wall temperature with time was derived by Illingworth (1950) and for Pr # 1.0, he derived the solution in integral form. Siegel (1958) studied the unsteady freeconvection flow past a semi-infinite vertical plate under stepchange in wall temperature or surface heat flux by employing the momentum integral method. Experimental evidence for such a situation was presented by Goldstein and Eckert (1960). For a semi-infinite vertical plate, unsteady free-convection flow was studied analytically b

    Acclimation of Oxygenic Photosynthesis to Iron Starvation Is Controlled by the sRNA IsaR1

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    Oxygenic photosynthesis crucially depends on proteins that possess Fe (2+) or Fe/S complexes as co-factors or prosthetic groups. Here, we show that the small regulatory RNA (sRNA) IsaR1 (Iron-Stress-Activated RNA 1) plays a pivotal role in acclimation to low-iron conditions. The IsaR1 regulon consists of more than 15 direct targets, including Fe (2+)-containing proteins involved in photosynthetic electron transfer, detoxification of anion radicals, citrate cycle, and tetrapyrrole biogenesis. IsaR1 is essential for maintaining physiological levels of Fe/S cluster biogenesis proteins during iron deprivation. Consequently, IsaR1 affects the acclimation of the photosynthetic apparatus to iron starvation at three levels: (1) directly, via posttranscriptional repression of gene expression; (2) indirectly, via suppression of pigment; and (3) Fe/S cluster biosynthesis. Homologs of IsaR1 are widely conserved throughout the cyanobacterial phylum. We conclude that IsaR1 is a critically important riboregulator. These findings provide a new perspective for understanding the regulation of iron homeostasis in photosynthetic organisms.German Federal Ministry of Education and Research [0316165]DFG [HE 2544/9-1]Academy of Finland [253269, 271832, 273870]Portuguese Fundacao para a Ciencia e a Tecnologia [IF/00881/2013, UID/Multi/04326/2013-CCMAR]European Commission FP7 Marie Curie Initial Training Network "Photo.COMM'' [317184]info:eu-repo/semantics/publishedVersio

    Flavodiiron Proteins in Oxygenic Photosynthetic Organisms: Photoprotection of Photosystem II by Flv2 and Flv4 in Synechocystis sp. PCC 6803

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    BACKGROUND: Flavodiiron proteins (FDPs) comprise a group of modular enzymes that function in oxygen and nitric oxide detoxification in Bacteria and Archaea. The FDPs in cyanobacteria have an extra domain as compared to major prokaryotic enzymes. The physiological role of cyanobacteria FDPs is mostly unknown. Of the four putative flavodiiron proteins (Flv1-4) in the cyanobacterium Synechocystis sp. PCC 6803, a physiological function in Mehler reaction has been suggested for Flv1 and Flv3. PRINCIPAL FINDINGS: We demonstrate a novel and crucial function for Flv2 and Flv4 in photoprotection of photosystem II (PSII) in Synechocystis. It is shown that the expression of Flv2 and Flv4 is high under air level of CO(2) and negligible at elevated CO(2). Moreover, the rate of accumulation of flv2 and flv4 transcripts upon shift of cells from high to low CO(2) is strongly dependent on light intensity. Characterization of FDP inactivation mutants of Synechocystis revealed a specific decline in PSII centers and impaired translation of the D1 protein in Delta flv2 and Delta flv4 when grown at air level CO(2) whereas at high CO(2) the Flvs were dispensable. Delta flv2 and Delta flv4 were also more susceptible to high light induced inhibition of PSII than WT or Delta flv1 and Delta flv3. SIGNIFICANCE: Analysis of published sequences revealed the presence of cyanobacteria-like FDPs also in some oxygenic photosynthetic eukaryotes like green algae, mosses and lycophytes. Our data provide evidence that Flv2 and Flv4 have an important role in photoprotection of water-splitting PSII against oxidative stress when the cells are acclimated to air level CO(2). It is conceivable that the function of FDPs has changed during evolution from protection against oxygen in anaerobic microbes to protection against reactive oxygen species thus making the sustainable function of oxygen evolving PSII possible. Higher plants lack FDPs and distinctly different mechanisms have evolved for photoprotection of PSII
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