889 research outputs found

    A Conversation with Dorothy Gilford

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    In 1946, Public Law 588 of the 79th Congress established the Office of Naval Research (ONR). Its mission was to plan, foster and encourage scientific research in support of Naval problems. The establishment of ONR predates the National Science Foundation and initiated the refocusing of scientific infrastructure in the United States following World War II. At the time, ONR was the only source for federal support of basic research in the United States. Dorothy Gilford was one of the first Heads of the Probability and Statistics program at the Office of Naval Research (1955 to 1962), and she went on to serve as Director of the Mathematical Sciences Division (1962 to 1968). During her time at ONR, Dorothy influenced many areas of statistics and mathematics and was ahead of her time in promoting interdisciplinary projects. Dorothy continued her career at the National Center for Education Statistics (1969 to 1974). She was active in starting international comparisons of education outcomes in different countries, which has influenced educational policy in the United States. Dorothy went on to serve in many capacities at the National Academy of Sciences, including Director of Human Resources Studies (1975 to 1978), Senior Statistician on the Committee on National Statistics (1978 to 1988) and Director of the Board on International Comparative Studies in Education (1988 to 1994). The following is a conversation we had with Dorothy Gilford in March of 2004. We found her to be an interesting person and a remarkable statistician. We hope you agree.Comment: Published in at http://dx.doi.org/10.1214/088342307000000023 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

    An Investigation of Novel Object Recognition Memory in a North American River Otter (Lontra canadensis)

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    Memory is the mental processes of receiving and storing information for later retrieval, with long-term memories being those that are stored longer than 30 seconds. Little research has been done to investigate memory in any of the 13 species of otters. Object recognition memory has the potential to aid otters in identifying conspecifics, prey, and predators, which would contribute to better survival and fitness. Object recognition memory has been investigated in many non-human animals using the novel object recognition (NOR) task. This study was the first to investigate long-term object recognition memory in the North American river otter using the NOR task. The subject was one adult male otter, Sailor, that resided at the Seneca Park Zoo in Rochester, NY. The stimulus pairs for this task were multimodal (3D objects and odorants) to take advantage of multisensory facilitation. The current study investigated three memory intervals: 10 minutes, 1 hour, and 24 hours (each interval included 10 sessions). There were two dependent variables: time spent with each stimulus pair and number of explorations (the otter making physical contact with, or being within a few centimeters of the stimulus pair). The results did not provide evidence for memory at any of the memory intervals. This may have been due to the otter spending significantly more time on the left side of the enclosure because of the experimental setup. Other limitations included the single-subject design and lack of information about what is discriminable in both vision and olfaction in otters. Future research should further investigate long-term memory in otters using either the NOR task or a puzzle feeder task, as well as with additional otter subjects. There is still much to be learned about memory in otters, which could have applications for animal welfare in zoos and can inform conservation efforts for otters

    Quasidegeneracy of Majorana Neutrinos and the Origin of Large Leptonic Mixing

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    We propose that the observed large leptonic mixing may just reflect a quasidegeneracy of three Majorana neutrinos. The limit of exact degeneracy of Majorana neutrinos is not trivial, as leptonic mixing and even CP violation may occur. We conjecture that the smallness of ∣U13∣|U_{13}|, when compared to the other elements of UPMNSU_{PMNS}, may just reflect the fact that, in the limit of exact mass degeneracy, the leptonic mixing matrix necessarily has a vanishing element. We show that the lifting of the mass degeneracy can lead to the measured value of ∣U13∣|U_{13}| while at the same time accommodating the observed solar and atmospheric mixing angles. In the scenario we consider for the breaking of the mass degeneracy there is only one CP violating phase, already present in the limit of exact degeneracy, which upon the lifting of the degeneracy generates both Majorana and Dirac-type CP violation in the leptonic sector. We analyse some of the correlations among physical observables and point out that in most of the cases considered, the implied strength of leptonic Dirac-type CP violation is large enough to be detected in the next round of experiments.Comment: 16 pages, 4 figures. Matches published version, references added, improved discussion, results unchange

    Herijking EHS Noord-Holland : een toets vanuit het perspectief van ruimtelijke samenhang

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    De realisatie van de Ecologische Hoofdstructuur in de Provincie Noord-Holland ligt achter op schema. Hierom hebben Gedeputeerde Staten van Noord-Holland besloten te onderzoeken of via een herbegrenzing een groter deel van de EHS nog is te realiseren. De gebieden die in aanmerking komen voor herbegrenzing zijn beoordeeld op de ruimtelijke samenhang van het gebied zelf én de mate waarin het gebied bijdraagt aan de omgeving. Op basis van de analyses mag geconcludeerd worden dat de beoogde herbegrenzing in Noord-Holland goed is voor de ruimtelijke samenhang van de provinciale EHS. Tevens zijn er twee quick-scan analyses uitgevoerd die een positief beeld laten zien van de herbegrenzingen op het niveau van Natuurdoelen en in relatie tot Natura2000-gebieden

    A deterministic method for robust estimation of multivariate location and shape

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    Visual perception of photographs of rotated 3D objects in goldfish (Carassius auratus)

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    © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Wegman, J. J., Morrison, E., Wilcox, K. T., & DeLong, C. M. Visual perception of photographs of rotated 3D objects in goldfish (Carassius auratus). Animals, 12(14), (2022): 1797, https://doi.org/10.3390/ani12141797.This study examined goldfishes’ ability to recognize photographs of rotated 3D objects. Six goldfish were presented with color photographs of a plastic model turtle and frog at 0° in a two-alternative forced-choice task. Fish were tested with stimuli at 0°, 90°, 180°, and 270° rotated in the picture plane and two depth planes. All six fish performed significantly above chance at all orientations in the three rotation planes tested. There was no significant difference in performance as a function of aspect angle, which supported viewpoint independence. However, fish were significantly faster at 180° than at +/−90°, so there is also evidence for viewpoint-dependent representations. These fish subjects performed worse overall in the current study with 2D color photographs (M = 88.0%) than they did in our previous study with 3D versions of the same turtle and frog stimuli (M = 92.6%), although they performed significantly better than goldfish in our two past studies presented with black and white 2D stimuli (M = 67.6% and 69.0%). The fish may have relied on color as a salient cue. This study was a first attempt at examining picture-object recognition in fish. More work is needed to determine the conditions under which fish succeed at object constancy tasks, as well as whether they are capable of perceiving photographs as representations of real-world objectsThis work was supported with a RIT College of Liberal Arts Faculty Development Grant to CMD and the RIT Paul A. and Francena L. Miller Research Fellowship awarded to CMD from the Rochester Institute of Technology

    Dark Vector-Gauge-Boson Model

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    A model based on SU(3)_C X SU(2)_L X U(1)_Y X SU(2)_N has recently been proposed, where the SU(2)_N vector gauge bosons are neutral, so that a vector dark-matter candidate is possible and constrained by data to be less than about 1 TeV. We explore further implications of this model, including a detailed study of its Higgs sector. We improve on its dark-matter phenomenology, as well as its discovery reach at the LHC (Large Hadron Collider).Comment: 15 pages, 4 figure

    X-ray modelling of galaxy cluster gas and mass profiles

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    We present a parametric analysis of the intracluster medium and gravitating mass distribution of a statistical sample of 20 galaxy clusters using the phenomenological cluster model of Ascasibar and Diego. We describe an effective scheme for the estimation of errors on model parameters and derived quantities using bootstrap resampling. We find that the model provides a good description of the data in all cases and we quantify the mean fractional intrinsic scatter about the best-fit density and temperature profiles, finding this to have median values across the sample of 2 and 5 per cent, respectively. In addition, we demonstrate good agreement between r500 determined directly from the model and that estimated from a core-excluded global spectrum. We compare cool core and non-cool core clusters in terms of the logarithmic slopes of their gas density and temperature profiles and the distribution of model parameters and conclude that the two categories are clearly separable. In particular, we confirm the effectiveness of the logarithmic gradient of the gas density profile measured at 0.04 r500 in differentiating between the two types of cluster.Comment: 8 pages, 7 figures, accepted for publication in MNRA
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