1,197 research outputs found

    Early Size Distributions of Chondrule Subgroups Overprinted by the Final Accumulation Process of Particle Components in Allende

    Get PDF
    Populations of compositionally distinct particles are fundamental components of undifferentiated chondritic meteorites. Many theories explain the formation of chondrites, one class of which includes mechanisms for sorting the component particles in the solar nebula prior to their accretion. Mechanisms include sorting by mass, turbulent concentration, X-winds, and photophoresis, which will produce characteristic distributions of observable properties such as particle size. Distinguishing processes that occur in specific astrophysical environments requires characterization of particle types, which include refractory Ca-Al-rich Inclusions (CAIs) and less-refractory chondrules. Previous investigations of modal abundances of CAIs and chondrules exist, but differences within and between these two groups, both of which are made up of diverse subgroups with different thermal histories and chemical compositions, remain mostly unstudied. The presence of rims, a significant event occurring after the formation of at least some chondrules, have also yet to be considered with respect to sorting. Here we present the sizes of CAIs and chondrules in Allende with attention to the smallest sizes, subgroups, and particle rims

    Enhancing Rural Manufacturers Competitiveness Through Design Automation For New Product Development

    Get PDF
    The competitiveness of third world manufacturing has placed pressure on U.S. manufacturers to create new products to survive.Ā Ā Computer aided solid modeling and rapid prototyping technologies accelerate new product development, but rural manufacturers are often left behind.Ā Ā This paper describes a cooperative venture between a state university and a federal agency to improve the new product development process of selected rural manufacturers by introducing them to leading-edge design automation technologies. Use of these tools allows better cross-functional communication among top management, marketing, designers, engineers, and manufacturing as they proceed through the new product creation process. Participating companies produced new product options, enhanced employment, and increased revenues

    Molecular and mass spectroscopic analysis of isotopically labeled organic residues

    Get PDF
    Experimental studies aimed at understanding the evolution of complex organic molecules on interstellar grains were performed. The photolysis of frozen gas mixtures of various compositions containing H2O, CO, NH3, and CH4 was studied. These species were chosen because of their astrophysical importance as deducted from observational as well as theoretical studies of ice mantles on interstellar grains. These ultraviolet photolyzed ices were warmed up in order to produce refractory organic molecules like the ones formed in molecular clouds when the icy mantles are being irradiated and warmed up either by a nearby stellar source or impulsive heating. The laboratory studies give estimates of the efficiency of production of such organic material under interstellar conditions. It is shown that the gradual carbonization of organic mantles in the diffuse cloud phase leads to higher and higher visual absorptivity - yellow residues become brown in the laboratory. The obtained results can be applied to explaining the organic components of comets and their relevance to the origin of life

    Editorial foreword: Angiogenesis: Cells, tissues and organs

    Get PDF
    On the occasion of his 90th birthday, this Special Issue is dedicated to Professor Robert Auerbach. Born 1929 in Berlin, Germany, he and his family escaped Nazi Germany in 1939 and emigrated to the United States, where he became a zoologist and ultimately Professor and Director of the Developmental Biology Training Program at the Department of Zoology, Madison, University of Wisconsin, USA. In Auerbach's laboratory, students and scientists of many different nations, including politically persecuted ones, harmoniously worked together on different aspects of angiogenesis. One of the hallmarks of Auerbach's career as a scientist was and is his generosity towards others, sharing his equipment and ideas freely, his integrity and his collegiality. His significant contributions to angiogenesis and tumour research include the finding that angiogenesis in tumours can occur even after their irradiation (Auerbach, Arensman, Kubai, & Folkman, 1975) and an explanation of organ selectivity in the spread of metastasizing cancer cells (Auerbach, 1988). Through his outstanding papers on in vitro methods in angiogenesis research, he also supported animal welfare (Alby & Auerbach, 1984; Auerbach, Lewis, Shinners, Kubai, & Akhtar, 2003; Gumkowski, Kaminska, Kaminski, Morrissey, & Auerbach, 1987; Obeso, Weber, & Auerbach, 1990)

    Monitoring Fish Diversity in Massies Creek, Ohio

    Get PDF
    Streams are susceptible to numerous threats to their water quality and biodiversity. In our region of southwest Ohio a major driver of these impacts is associated with current and past agricultural practices. These changes include straightening, embanking, dredging, and removal of large rocks and woody debris, increased erosion, and non-point source pollution. These structural and chemical impacts are known to significantly affect biodiversity in these streams. This means a greater understanding of stream ecology is of utter importance to places such as Greene County, Ohio due to the prevalence of agricultural practices in the landscape. In 2010 a 2.2 mile stream restoration project was completed by Greene County on the north fork of Massieā€™s Creek. Biological surveys and stream monitoring began in 2011 and extended on a regular basis through Fall 2014. In our study, conducted in the fall of 2014, we expanded the scope to evaluate fish biodiversity at previously studied sites as well as four additional sites within the watershed. Our objective was to collect data in order to draw comparisons between 2014 and previous yearā€™s data including a study conducted in 1955 on Massieā€™s Creek. We sampled in six different locations, once in all six sites and twice in two specific sites. We used a mix of restored, unrestored, and unaltered stretches of stream as our sample locations. To determine diversity we used two different diversity indices: Shannon (H) and Simpsonā€™s (D). Our Shannon value for the common unrestored site was 1.46 and our Simpsonā€™s value was 0.33. Our Shannon value for the common restored site was 1.22 and our Simpsonā€™s value was 0.36. Combining the data from the previous years with the 2014 data we found dominance to have decreased after restoration (which means there was more diversity)

    Metacognition as Evidence for Evidentialism

    Get PDF
    Metacognition is the monitoring and controlling of cognitive processes. I examine the role of metacognition in ā€˜ordinary retrieval casesā€™, cases in which it is intuitive that via recollection the subject has a justiļ¬ed belief. Drawing on psychological research on metacognition, I argue that evidentialism has a unique, accurate prediction in each ordinary retrieval case: the subject has evidence for the proposition she justiļ¬edly believes. But, I argue, process reliabilism has no unique, accurate predictions in these cases. I conclude that ordinary retrieval cases better support evidentialism than process reliabilism. This conclusion challenges several common assumptions. One is that non-evidentialism alone allows for a naturalized epistemology, i.e., an epistemology that is fully in accordance with scientiļ¬c research and methodology. Another is that process reliabilism fares much better than evidentialism in the epistemology of memory

    The HI and Ionized Gas Disk of the Seyfert Galaxy NGC 1144 = Arp 118: A Violently Interacting Galaxy with Peculiar Kinematics

    Get PDF
    We present observations of the distribution and kinematics of neutral and ionized gas in NGC 1144, a galaxy that forms part of the Arp 118 system. Ionized gas is present over a huge spread in velocity (1100 km/s) in the disk of NGC 1144, but HI emission is detected over only 1/3 of this velocity range, in an area that corresponds to the NW half of the disk. In the nuclear region of NGC 1144, a jump in velocity in the ionized gas component of 600 km/s is observed. Faint, narrow HI absorption lines are also detected against radio sources in the SE part of the disk of NGC 1144, which includes regions of massive star formation and a Seyfert nucleus. The peculiar HI distribution, which is concentrated in the NW disk, seems to be the inverse of the molecular distribution which is concentrated in the SE disk. Although this may partly be the result of the destruction of HI clouds in the SE disk, there is circumstantial evidence that the entire HI emission spectrum of NGC 1144 is affected by a deep nuclear absorption line covering a range of 600 km/s, and is likely blueshifted with respect to the nucleus. In this picture, a high column-density HI stream is associated with the nuclear ionized gas velocity discontinuity, and the absorption effectively masks any HI emission that would be present in the SE disk of NGC 1144.Comment: manuscript, arp118.ps: 28 pages; 1 Table: arp118.tab1.ps; 16 Figures: arp118.fig1-16.ps; Accepted to Ap

    Non-Newtonian fluid flow through three-dimensional disordered porous media

    Full text link
    We investigate the flow of various non-Newtonian fluids through three-dimensional disordered porous media by direct numerical simulation of momentum transport and continuity equations. Remarkably, our results for power-law (PL) fluids indicate that the flow, when quantified in terms of a properly modified permeability-like index and Reynolds number, can be successfully described by a single (universal) curve over a broad range of Reynolds conditions and power-law exponents. We also study the flow behavior of Bingham fluids described in terms of the Herschel-Bulkley model. In this case, our simulations reveal that the interplay of ({\it i}) the disordered geometry of the pore space, ({\it ii}) the fluid rheological properties, and ({\it iii}) the inertial effects on the flow is responsible for a substantial enhancement of the macroscopic hydraulic conductance of the system at intermediate Reynolds conditions. This anomalous condition of ``enhanced transport'' represents a novel feature for flow in porous materials.Comment: 5 pages, 5 figures. This article appears also in Physical Review Letters 103 194502 (2009

    Standing in a Garden of Forking Paths

    Get PDF
    According to the Path Principle, it is permissible to expand your set of beliefs iff (and because) the evidence you possess provides adequate support for such beliefs. If there is no path from here to there, you cannot add a belief to your belief set. If some thinker with the same type of evidential support has a path that they can take, so do you. The paths exist because of the evidence you possess and the support it provides. Evidential support grounds propositional justification. The principle is mistaken. There are permissible steps you may take that others may not even if you have the very same evidence. There are permissible steps that you cannot take that others can even if your beliefs receive the same type of evidential support. Because we have to assume almost nothing about the nature of evidential support to establish these results, we should reject evidentialism

    Whither Evidentialist Reliabilism?

    Get PDF
    Evidentialism and Reliabilism are two of the main contemporary theories of epistemic justification. Some authors have thought that the theories are not incompatible with each other, and that a hybrid theory which incorporates elements of both should be taken into account. More recently, other authors have argued that the resulting theory is well- placed to deal with fine-grained doxastic attitudes (credences). In this paper I review the reasons for adopting this kind of hybrid theory, paying attention to the case of credences and the notion of probability involved in their treatment. I argue that the notion of probability in question can only be an epistemic (or evidential) kind of probability. I conclude that the resulting theory will be incompatible with Reliabilism in one important respect: it cannot deliver on the reductivist promise of Reliabilism. I also argue that attention to the justification of basic beliefs reveals limitations in the Evidentialist framework as well. The theory that results from the right combination of Evidentialism and Reliabilism, therefore, is neither Evidentialist nor Reliabilist
    • ā€¦
    corecore