22,770 research outputs found

    A redshift survey towards the CMB Cold Spot

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    We have carried out a redshift survey using the VIMOS spectrograph on the VLT towards the Cosmic Microwave Background cold spot. A possible cause of the cold spot is the Integrated Sachs-Wolfe effect imprinted by an extremely large void (hundreds of Mpc in linear dimension) at intermediate or low redshifts. The redshift distribution of over seven hundred z<1 emission-line galaxies drawn from an I-band flux limited sample of galaxies in the direction of the cold spot shows no evidence of a gap on scales of Delta-z> 0.05 as would be expected if such a void existed at 0.35<z<1. There are troughs in the redshift distribution on smaller scales (Delta-z ~0.01) indicating that smaller scale voids may connect regions separated by several degrees towards the cold spot. A comparison of this distribution with that generated from similarly-sized subsamples drawn from widely-spaced pointings of the VVDS survey does not indicate that the redshift distribution towards the cold spot is anomalous or that these small gaps can be uniquely attributed to real voids.Comment: MNRAS in press, 6 page

    Anxiolytic effect of Mozart music over short and long photoperiods as part of environmental enrichment in captive Rattus norvegicus (Rodentia: Muridae)

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    Music is known to be able to elicit emotional changes, including anxiolytic effects on humans and animals. Photoperiod has also been reported to play an important role in the modulation of anxiety. In the present study, we examined whether the effect of music on anxiety is influenced by day length, comparing, short day (SD; 8:16 h light/dark) and long day (LD; 16:8 h light/dark) with controls (CD; 12:12 h light/dark). After 8 weeks of photoperiod treatment, rats were randomly assigned to 2 groups: silence and music. In the music group, rats were exposed to music 24 h before behavioral tests to quantify anxiety level. Exposure to Mozart music reduced anxiety in rats in the CD group. These effects of music were abolished by LD. Independently of music, rats exposed to SD exhibited higher levels of anxiety-like behavior than rats exposed to CD, in elevated plus-maze and open-field tests. The present findings suggest that the anxiolytic effects of Mozart music are photoperiod-dependent

    Explaining away, augmentation, and the assumption of independence

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    In reasoning about situations in which several causes lead to a common effect, a much studied and yet still not well-understood inference is that of explaining away. Assuming that the causes contribute independently to the effect, if we learn that the effect is present, then this increases the probability that one or more of the causes are present. But if we then learn that a particular cause is present, this cause “explains” the presence of the effect, and the probabilities of the other causes decrease again. People tend to show this explaining away effect in their probability judgments, but to a lesser extent than predicted by the causal structure of the situation. We investigated further the conditions under which explaining away is observed. Participants estimated the probability of a cause, given the presence or the absence of another cause, for situations in which the effect was either present or absent, and the evidence about the effect was either certain or uncertain. Responses were compared to predictions obtained using Bayesian network modeling as well as a sensitivity analysis of the size of normative changes in probability under different information conditions. One of the conditions investigated: when there is certainty that the effect is absent, is special because under the assumption of causal independence, the probabilities of the causes remain invariant, that is, there is no normative explaining away or augmentation. This condition is therefore especially diagnostic of people’s reasoning about common-effect structures. The findings suggest that, alongside earlier explanations brought forward in the literature, explaining away may occur less often when the causes are assumed to interact in their contribution to the effect, and when the normative size of the probability change is not large enough to be subjectively meaningful. Further, people struggled when given evidence against negative evidence, resembling a double negation effect

    Effect of the Milky Way on Magellanic Cloud structure

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    A combination of analytic models and n-body simulations implies that the structural evolution of the Large Magellanic Cloud (LMC) is dominated by its dynamical interaction with the Milky Way. Although expected at some level, the scope of the involvement has significant observational consequences. First, LMC disk orbits are torqued out of the disk plane, thickening the disk and populating a spheroid. The torque results from direct forcing by the Milky Way tide and, indirectly, from the drag between the LMC disk and its halo resulting from the induced precession of the LMC disk. The latter is a newly reported mechanism that can affect all satellite interations. However, the overall torque can not isotropize the stellar orbits and their kinematics remains disk-like. Such a kinematic signature is observed for nearly all LMC populations. The extended disk distribution is predicted to increase the microlensing toward the LMC. Second, the disk's binding energy slowly decreases during this process, puffing up and priming the outer regions for subsequent tidal stripping. Because the tidally stripped debris will be spatially extended, the distribution of stripped stars is much more extended than the HI Magellanic Stream. This is consistent with upper limits to stellar densities in the gas stream and suggests a different strategy for detecting the stripped stars. And, finally, the mass loss over several LMC orbits is predicted by n-body simulation and the debris extends to tens of kiloparsecs from the tidal boundary. Although the overall space density of the stripped stars is low, possible existence of such intervening populations have been recently reported and may be detectable using 2MASS.Comment: 15 pages, color Postscript figures, uses emulateapj.sty. Also available from http://www-astro.phast.umass.edu/~weinberg/weinberg-pubs.htm

    Boundedness of Pseudodifferential Operators on Banach Function Spaces

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    We show that if the Hardy-Littlewood maximal operator is bounded on a separable Banach function space X(Rn)X(\mathbb{R}^n) and on its associate space X′(Rn)X'(\mathbb{R}^n), then a pseudodifferential operator Op⁡(a)\operatorname{Op}(a) is bounded on X(Rn)X(\mathbb{R}^n) whenever the symbol aa belongs to the H\"ormander class Sρ,δn(ρ−1)S_{\rho,\delta}^{n(\rho-1)} with 0<ρ≤10<\rho\le 1, 0≤δ<10\le\delta<1 or to the the Miyachi class Sρ,δn(ρ−1)(ϰ,n)S_{\rho,\delta}^{n(\rho-1)}(\varkappa,n) with 0≤δ≤ρ≤10\le\delta\le\rho\le 1, 0≤δ00\le\delta0. This result is applied to the case of variable Lebesgue spaces Lp(⋅)(Rn)L^{p(\cdot)}(\mathbb{R}^n).Comment: To appear in a special volume of Operator Theory: Advances and Applications dedicated to Ant\'onio Ferreira dos Santo

    The Influence of Pay as a Motivator on the Research Productivity of Educators

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    Research is one of a university’s primary functions. This study aimed to determine the influence of pay as a motivator on the research productivity of educators. It utilized a mixed-methods research design. The respondents are 150 faculty members randomly selected during the 1st semester of the SY 2022-2023. It used a validated survey instrument. The results show a 0.279 weakly positive correlation between the two variables. The computed t-value for this predictor exceeds the 95% confidence interval of (.492, 1.735) by a significant margin of p=0.001, hence the researchers reject the null hypothesis, which states that pay as a motivator significantly does not influence research productivity. For the qualitative phase, the emerging themes include the issues and problems regarding research productivity including lack of time due to work overload, lack of knowledge in research writing, tedious procedures in the research approval, and lack of work motivation/encouragement. Thus, the researchers crafted recommendations that could help enhance faculty members ’ research productivity
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