169 research outputs found

    Bridging the gap:human emotions and animal emotions

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    Our experiences of the conscious mental states that we call emotions drive our interest in whether such states also exist in other animals. Because linguistic report can be used as a gold standard (albeit indirect) indicator of subjective emotional feelings in humans but not other species, how can we investigate animal emotions and what exactly do we mean when we use this term? Linguistic reports of human emotion give rise to emotion concepts (discrete emotions; dimensional models), associated objectively measurable behavioral and bodily emotion indicators, and understanding of the emotion contexts that generate specific states. We argue that many animal studies implicitly translate human emotion concepts, indicators and contexts, but that explicit consideration of the underlying pathways of inference, their theoretical basis, assumptions, and pitfalls, and how they relate to conscious emotional feelings, is needed to provide greater clarity and less confusion in the conceptualization and scientific study of animal emotion

    The nuclear spectrum of the radio galaxy NGC 5128 (Centaurus A)

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    We present near-infrared spectra of the nuclear disk in the nearby radio galaxy NGC 5128 (Centaurus A). On the basis of the observed strengths of the [S III] 0.9532um and [Fe II] 1.2567um lines, we classify NGC 5128 as a LINER. Modeling of the strengths of these and additional lines suggests that the nuclear region is powered by shocks rather than photoionization.Comment: 12 pages including 2 figures, accepted by ApJ Letter

    Analyzing Mutations of Spt7 Protein That Disrupt Interaction with SF3B Subunits

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    Proper transcription, the process of converting DNA to RNA, is crucial for the health and viability of an organism. This process is regulated by many proteins, such as co-transcriptional activators; one being the protein complex known as Spt-Ada-Gcn5-acetyltransferase, or SAGA. While much is known about the roles of SAGA in cell processes, how SAGA’s subunits promote functionality is still unknown. The focus of this study is to analyze the purpose of SAGA’s SF3B subunits. These subunits are also found in the spliceosome, the compound responsible for generating mature RNA. SAGA has no known functions relating to this process, so the reason the SF3B components are in SAGA is unclear. Spt7, another SAGA subunit, interacts with both SF3B subunits. In this study, a yeast two hybrid assay was performed where different Spt7 mutants were screened. This was done by transforming yeast with Spt7 mutants, analyzing the protein interactions and sequencing the mutants to determine their mutations. A key result of this study is in the determining that the two SF3B subunits interact with different regions of Spt7. Although the overall goal is to find an Spt7 mutant that does not interact with the SF3B components but still maintains interaction with other SAGA subunits, we now have a better idea of what type of Spt7 mutant is needed. This discovery will lay the foundation for future experiments where a mutated SAGA with no SF3B components will be expressed in Drosophila melanogaster and analyzed to determine the function of SF3B subunits in SAGA

    Dissecting the links between reward and loss, decision-making, and self-reported affect using a computational approach

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    Links between affective states and risk-taking are often characterised using summary statistics from serial decision-making tasks. However, our understanding of these links, and the utility of decision-making as a marker of affect, needs to accommodate the fact that ongoing (e.g., within-task) experience of rewarding and punishing decision outcomes may alter future decisions and affective states. To date, the interplay between affect, ongoing reward and punisher experience, and decision-making has received little detailed investigation. Here, we examined the relationships between reward and loss experience, affect, and decision-making in humans using a novel judgement bias task analysed with a novel computational model. We demonstrated the influence of within-task favourability on decision-making, with more risk-averse/'pessimistic' decisions following more positive previous outcomes and a greater current average earning rate. Additionally, individuals reporting more negative affect tended to exhibit greater risk-seeking decision-making, and, based on our model, estimated time more poorly. We also found that individuals reported more positive affective valence during periods of the task when prediction errors and offered decision outcomes were more positive. Our results thus provide new evidence that (short-term) within-task rewarding and punishing experiences determine both future decision-making and subjectively experienced affective states

    Stellar Populations at the Center of IC 1613

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    We have observed the center of the Local Group dwarf irregular galaxy IC 1613 with WFPC2 aboard the Hubble Space Telescope in the F439W, F555W, and F814W filters. We find a dominant old stellar population (aged ~7 Gyr), identifiable by the strong red giant branch (RGB) and red clump populations. From the (V-I) color of the RGB, we estimate a mean metallicity of the intermediate-age stellar population [Fe/H] = -1.38 +/- 0.31. We confirm a distance of 715 +/- 40 kpc using the I-magnitude of the RGB tip. The main-sequence luminosity function down to I ~25 provides evidence for a roughly constant SFR of approximately 0.00035 solar masses per year across the WFPC2 field of view (0.22 square kpc) during the past 250-350 Myr. Structure in the blue loop luminosity function implies that the SFR was ~50% higher 400-900 Myr ago than today. The mean heavy element abundance of these young stars is 1/10th solar. The best explanation for a red spur on the main-sequence at I = 24.7 is the blue horizontal branch component of a very old stellar population at the center of IC 1613. We have also imaged a broader area of IC 1613 using the 3.5-meter WIYN telescope under excellent seeing conditions. The AGB-star luminosity function is consistent with a period of continuous star formation over at least the age range 2-10 Gyr. We present an approximate age-metallicity relation for IC 1613, which appears similar to that of the Small Magellanic Cloud. We compare the Hess diagram of IC 1613 to similar data for three other Local Group dwarf galaxies, and find that it most closely resembles the nearby, transition-type dwarf galaxy Pegasus (DDO 216).Comment: To appear in the September 1999 Astronomical Journal. LaTeX, uses AASTeX v4.0, emulateapj style file, 19 pages, 12 postscript figures, 2 tables. 5 of the figures available separately via the WW
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