101,793 research outputs found
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
The devil is in the detail: Zebrafish learn to discriminate visual stimuli only if salient
No full textDue to their unique characteristics, the zebrafish plays a key role in the comprehension of neurobiology of cognition and its pathologies, such as neurodegenerative diseases. More and more molecular tools for this aim are being developed, but our knowledge about the cognitive abilities of zebrafish remains extremely scarce compared to other teleost fish. We aimed to investigate the complex cognitive abilities of zebrafish using a tracking-based automated conditioning chamber that allowed precise experimental control, avoided potential cueing provided by the observer (Clever Hans phenomenon), and was shown to considerably improve learning in other teleosts. A computer presented two visual stimuli in two sectors of the chamber, and zebrafish had to enter the correct sector to obtain a food reward. Zebrafish quickly learned to use the conditioning device and easily performed up to 80 trials per day. In Experiment 1, zebrafish efficiently discriminated between two differently coloured sides, reaching a 75 % accuracy in only 10 training sessions. Surprisingly, zebrafish failed to choose the correct chamber when the stimuli were two shapes, a small circle and a small triangle, even when, in Experiment 2, training on shape discrimination was prolonged for up to 30 sessions. In Experiment 3, we tested the hypothesis that simultaneously learning to use the conditioning chamber and learning discrimination imposes a too-high cognitive load. However, zebrafish that first successfully learned how the conditioning chamber functioned (in the colour discrimination) subsequently failed in the shape discrimination. Conversely, zebrafish that firstly failed the shape discrimination subsequently learned colour discrimination. In Experiment 4, zebrafish showed some evidence of learning when the stimuli were two large shapes, suggesting that zebrafish did not discriminate between the shapes of the previous experiments because they were not salient enough. Altogether, results suggest constraints in the discrimination learning abilities of zebrafish, which should be taken into account when developing cognitive tasks for this species
Handwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Understanding and building upon pioneering work of Nobel Prize in Physics 2021 laureates Syukuro Manabe and Klaus Hasselmann: From greenhouse effect to Earth system science and beyond
No full textThe Nobel Prize in Physics 2021 was awarded jointly to Syukuro Manabe, Klaus Hasselmann, and Giorgio Parisi for their groundbreaking contributions to our understanding of complex systems. This is the first time that climate scientists were awarded the Nobel Physics Prize. Here, we present the evolution of climate science in the past similar to 200 years and highlight the landmarks of the developments in advancing our understanding of climate change, placing the pioneering contributions of Manabe and Hasselmann into a historical perspective. The backbone of modern climate science is further discussed in the context of the development of the discipline from the discovery of the greenhouse effect to the formation of Earth system science. Perspectives on the future development of climate science are also presented
Understanding and building upon pioneering work of Nobel Prize in Physics 2021 laureates Syukuro Manabe and Klaus Hasselmann: From greenhouse effect to Earth system science and beyond
No full textThe Nobel Prize in Physics 2021 was awarded jointly to Syukuro Manabe, Klaus Hasselmann, and Giorgio Parisi for their groundbreaking contributions to our understanding of complex systems. This is the first time that climate scientists were awarded the Nobel Physics Prize. Here, we present the evolution of climate science in the past similar to 200 years and highlight the landmarks of the developments in advancing our understanding of climate change, placing the pioneering contributions of Manabe and Hasselmann into a historical perspective. The backbone of modern climate science is further discussed in the context of the development of the discipline from the discovery of the greenhouse effect to the formation of Earth system science. Perspectives on the future development of climate science are also presented
Pelevin’s Trinity in the novel “t”: author – protagonist – reader
No full textThe article attempts to interpret Pelevin's artistic strategy in the novel "T" by exploring its subject organization and addressing the key problems of the author, the protagonist, and the reader as they are seen by the researcher. The article analyzes the peculiarities of constructing the narrative reality in the novel "T", and goes on to discuss Pelevin's philosophic models of the development of the humankind, and the emergence of his new anthropology
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