2,892 research outputs found

    First results with the boloSource() algorithm: Photometry of faint standard stars observed by Herschel/PACS

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    The boloSource() algorithm is a tool to separate the signal of compact sources from that of the diffuse background in the timeline of far-infrared measurements performed by the PACS camera of the Herschel Space Observatory. An important characteristic and quality indicator of this method is that how well it can reproduce the flux of faint standard stars which have reliable flux estimates. For this propose we selected a few calibrator targets and constructed light curves by extracting point source flux for each repetition of the measurements independently using standard aperture photometry methods. These were compared with the light curves obtained using the boloSource() method on the same dataset. The results indicate that boloSource() provides a similar level of photometric accuracy and reproducibility as the usual flux extraction and photometry methods. This new technique will be developed further and also tested against other methods in more complex fields with the goal to make it usable for large-scale studies in the future.Comment: 10 pages, 7 figures, 4 table

    PACS photometer calibration block analysis

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    The absolute stability of the PACS bolometer response over the entire mission lifetime without applying any corrections is about 0.5% (standard deviation) or about 8% peak-to-peak. This fantastic stability allows us to calibrate all scientific measurements by a fixed and time-independent response file, without using any information from the PACS internal calibration sources. However, the analysis of calibration block observations revealed clear correlations of the internal source signals with the evaporator temperature and a signal drift during the first half hour after the cooler recycling. These effects are small, but can be seen in repeated measurements of standard stars. From our analysis we established corrections for both effects which push the stability of the PACS bolometer response to about 0.2% (stdev) or 2% in the blue, 3% in the green and 5% in the red channel (peak-to-peak). After both corrections we still see a correlation of the signals with PACS FPU temperatures, possibly caused by parasitic heat influences via the Kevlar wires which connect the bolometers with the PACS Focal Plane Unit. No aging effect or degradation of the photometric system during the mission lifetime has been found.Comment: 15 pages, accepted for publication in Experimental Astronom

    A general theory of intertemporal decision-making and the perception of time

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    Animals and humans make decisions based on their expected outcomes. Since relevant outcomes are often delayed, perceiving delays and choosing between earlier versus later rewards (intertemporal decision-making) is an essential component of animal behavior. The myriad observations made in experiments studying intertemporal decision-making and time perception have not yet been rationalized within a single theory. Here we present a theory-Training--Integrated Maximized Estimation of Reinforcement Rate (TIMERR)--that explains a wide variety of behavioral observations made in intertemporal decision-making and the perception of time. Our theory postulates that animals make intertemporal choices to optimize expected reward rates over a limited temporal window; this window includes a past integration interval (over which experienced reward rate is estimated) and the expected delay to future reward. Using this theory, we derive a mathematical expression for the subjective representation of time. A unique contribution of our work is in finding that the past integration interval directly determines the steepness of temporal discounting and the nonlinearity of time perception. In so doing, our theory provides a single framework to understand both intertemporal decision-making and time perception.Comment: 37 pages, 4 main figures, 3 supplementary figure

    "optimism Is a Strategy for Making a Better Future": A Systematic Review on the Associations of Dispositional Optimism with Health-Related Quality of Life in Cancer Patients

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    Cancer is a deadly disease that can lead to psychological suffering and decreased quality of life (QoL). Personality has been proven to have an effect on QoL and, in particular, Dispositional Optimism (DO) has been studied in relation to overcoming health crisis. The aim of this systematic review is to deepen the state of art of the relationship between QoL and DO in cancer patients. PubMed and Embase databases were systematically searched. Fifteen studies were included with a total of 5,249 cancer patients. All of the studies consider the relationship between DO and QoL, some studies analyze the correlation between the two variables and found a positive association. The majority of the studies investigate the predictive power of DO over QoL and most of them found DO to be predictive of a higher QoL. Results confirmed the association between DO and QoL in a sample of cancer patients. These results could influence the clinical practice as DO has been proven to have a beneficial effect on mental and physical health

    Student interaction with the interplay tool

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    [EN] Among the priorities of the Polytechnic University of Valencia¿s Education Science Institute (ICE in Spanish) is the training of university teachers, in which one of the subjects covered is the development and application of technological resources to improve the teaching-learning process. The ICE¿s Educational and Multimedia Resources Bureau (GREM in Spanish) has developed the InterPLAY teaching tool to promote changes that make it necessary to re-invent the teaching process, in which the teachers take on an innovative role and create conditions for the students to acquire new knowledge, experience and elements that generate analytical, reflective and acquisition processes. Apart from being a teaching video, InterPLAY allows the teacher to introduce information (recordings, videos, questions, images, files, graphs, embedded web pages, etc) and construct it in a way to suit teaching criteria, facilitate the students¿ learning, and especially generate interaction with the contents. There are clear standards for the correct use of the teaching resource in the subject [2]. It must be relevant, up-to-date and realistic, as well as have high image and audio quality, and of course assist in learning the contents to be studied. Both its design and production, the resource¿s foundation, and experimentation and evaluation are creatively and dynamically inserted into the teaching-learning process and can be used as a tool to develop competencies and skills in the students, who are benefitted by playing a more active learning role, making education more accessible and dynamic [3], This paper describes the characteristics of the practical formative sessions, which use an experiential method for teachers to learn to design their own teaching resources using InterPLAY [4]. The participants were teachers who give different engineering degree subjects, including master¿s degree courses. We also give an analysis of the evaluations given in the participants¿ responses to the questionnaire specially composed for this purpose at the end of the last two courses. These considered the evaluations as regards the didactic use of the tool, with an analysis of its impact on the learning process, its degree of interest, and the difficulties encountered in the tool¿s different applications, both from the teachers¿ and students¿ point of view. Using InterPLAY is a constant incentive for teachers to give more thought to their teaching methods.Rios, JG.; Garcia, E.; Marton Lluch, I. (2020). Student interaction with the interplay tool. IATED Academy. 4513-4520. https://doi.org/10.21125/edulearn.2020.1190S4513452

    Comet C/2013 A1 (Siding Spring) as seen with the Herschel Space Observatory

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    The thermal emission of comet C/2013 A1 (Siding Spring) was observed on March 31, 2013, at a heliocentric distance of 6.48 au using the PACS photometer camera of the Herschel Space Observatory. The comet was clearly active, showing a coma that could be traced to a distance of 10", i.e. 50000 km. Analysis of the radial intensity profiles of the coma provided dust mass and dust production rate; the derived grain size distribution characteristics indicate an overabundance of large grains in the thermal emission. We estimate that activity started about 6 months before these observations, at a heliocentric distance of 8 au.Comment: 4 pages, 3 figures + a one-page Appendix with 2 figures, accepted for publication in Astronomy & Astrophysics (Letter

    The Polyamine Binding Site in Inward Rectifier K+ Channels

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    Strongly inwardly rectifying potassium channels exhibit potent and steeply voltage-dependent block by intracellular polyamines. To locate the polyamine binding site, we have examined the effects of polyamine blockade on the rate of MTSEA modification of cysteine residues strategically substituted in the pore of a strongly rectifying Kir channel (Kir6.2[N160D]). Spermine only protected cysteines substituted at a deep location in the pore, between the “rectification controller” residue (N160D in Kir6.2, D172 in Kir2.1) and the selectivity filter, against MTSEA modification. In contrast, blockade with a longer synthetic polyamine (CGC-11179) also protected cysteines substituted at sites closer to the cytoplasmic entrance of the channel. Modification of a cysteine at the entrance to the inner cavity (169C) was unaffected by either spermine or CGC-11179, and spermine was clearly “locked” into the inner cavity (i.e., exhibited a dramatically slower exit rate) following modification of this residue. These data provide physical constraints on the spermine binding site, demonstrating that spermine stably binds at a deep site beyond the “rectification controller” residue, near the extracellular entrance to the channel
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