1,112 research outputs found

    Perceptions from the highline

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    Perceptions from the Highline is a concerto for electric guitar and chamber ensemble. As a composer and a guitarist, I am constantly searching for new and compelling ways to compose for the electric guitar in conjunction with acoustic instruments. The time-based effect known as delay or echo is commonly utilized in the sonic milieu of the electric guitar. This paper will examine the process of scoring musical ideas generated by the use of electric guitar and delay for an acoustic chamber ensemble within the context of Perceptions from the Highline. Many of the electric guitar sounds utilizing delay were initially observed in the context of rock and popular music. This paper will briefly examine three examples of electric guitar playing featuring the use of delay that were influential to the composition of this piece. Analyzing these delay textures generates new models for scoring and orchestration, which in turn creates a series of ensemble-wide composite textures and melodic lines. Perceptions From the Highline is a one-movement concerto for electric guitar and chamber ensemble featuring electronic delay textures scored for acoustic instruments. The composition is the main focus of this thesis, while the accompanying paper further details the compositional process. The score for Perceptions From the Highline is presented in Appendix A

    Comparing two evolutionary algorithm based methods for layout generation: Dense packing versus subdivision

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    We present and compare two evolutionary algorithm based methods for rectangular architectural layout generation: dense packing and subdivision algorithms. We analyze the characteristics of the two methods on the basis of three floor plan scenarios. Our analyses include the speed with which solutions are generated, the reliability with which optimal solutions can be found, and the number of different solutions that can be found overall. In a following step, we discuss the methods with respect to their different user interaction capabilities. In addition, we show that each method has the capability to generate more complex L-shaped layouts. Finally, we conclude that neither of the methods is superior but that each of them is suitable for use in distinct application scenarios because of its different propertie

    Telling the Story of Stepfamily Beginnings: The Relationship between Young-adult Stepchildren’s Stepfamily Origin Stories and their Satisfaction with the Stepfamily

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    The current study adopts a narrative perspective in examining the content of 80 stepchildren’s stepfamily origin stories. Results reveal five types of stepfamily origin stories: Sudden, Dark-sided, Ambivalent, Idealized, and Incremental. Results support the hypothesis that story type would predict differences in family satisfaction; stepchildren who described their stepfamily origins as Idealized were more satisfied than those whose origins were Dark-sided or Sudden. Overall, participants framed their stepfamily identity more positively when their stepfamily beginnings were characterized by closeness, friendship, and even expected ups and downs, rather than when they were left out of the process of negotiating or forming the stepfamily and when the beginnings were tainted by issues they considered to be dark. Stepparents or practitioners may benefit from these findings by examining the means by which stepparents may involve stepchildren in the process of stepfamily courtship, facilitate closeness, and set up realistic expectations for negotiating stepfamily life

    Shaping a mental health curriculum for Canada\u27s teacher education programs: Rationale and brief overview

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    It is a well-known and accepted statistic that one in five Canadian children will experience a significant mental health challenge prior to their 18th birthday; this is a conservative estimate given the many who suffer ‘under the radar’ with transient sadness, depression, and anxiety (Flett & Hewitt, 2013). And if we have yet to be sensitized to this critical period of childhood and adolescence, longitudinal studies indicate that 70% of adults who experience an emotional disorder report having their first onset episode prior to the age of 18 (Kessler et al., 2009)

    A Pan-Carina YSO Catalog: Intermediate-Mass Young Stellar Objects in the Carina Nebula Identified Via Mid-Infrared Excess Emission

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    We present a catalog of 1439 young stellar objects (YSOs) spanning the 1.42 deg^2 field surveyed by the Chandra Carina Complex Project (CCCP), which includes the major ionizing clusters and the most active sites of ongoing star formation within the Great Nebula in Carina. Candidate YSOs were identified via infrared (IR) excess emission from dusty circumstellar disks and envelopes, using data from the Spitzer Space Telescope Vela--Carina survey and the Two-Micron All Sky Survey. We model the 1--24 /mu m IR spectral energy distributions of the YSOs to constrain physical properties. Our Pan-Carina YSO Catalog (PCYC) is dominated by intermediate-mass (2 Msun < m < 10 Msun) objects with disks, including Herbig Ae/Be stars and their less evolved progenitors. The PCYC provides a valuable complementary dataset to the CCCP X-ray source catalogs, identifying 1029 YSOs in Carina with no X-ray detection. We also catalog 410 YSOs with X-ray counterparts, including 62 candidate protostars. Candidate protostars with X-ray detections tend to be more evolved than those without. In most cases, X-ray emission apparently originating from intermediate-mass, disk-dominated YSOs is consistent with the presence of low-mass companions, but we also find that X-ray emission correlates with cooler stellar photospheres and higher disk masses. We suggest that intermediate-mass YSOs produce X-rays during their early pre-main sequence evolution, perhaps driven by magnetic dynamo activity during the convective atmosphere phase, but this emission dies off as the stars approach the main sequence. Extrapolating over the stellar initial mass function scaled to the PCYC population, we predict a total population of >2x10^4 YSOs and a present-day star formation rate (SFR) of >0.008 Msun/yr. The global SFR in the Carina Nebula, averaged over the past ~5 Myr, has been approximately constant.Comment: 23 pages, 11 figures, accepted for the ApJS Special Issue on the Chandra Carina Complex Project (CCCP), scheduled for publication in May 2011. All 16 CCCP Special Issue papers, including a version of this article with high-quality figures and full electronic tables, are available at http://cochise.astro.psu.edu/Carina_public/special_issue.html (through 2011 at least

    Resource partitioning by insectivorous bats in Jamaica

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    In this investigation, we use variation in wing morphology, echolocation behaviour, patterns of habitat use and molecular diet analysis to demonstrate that six species of sympatric insectivorous bats in Jamaica show significant differences that could explain resource partitioning among the species. High-intensity echolocating species that used shorter, broadband signals and had shorter, broader wings (Pteronotus macleayii, Pteronotus quadridens, Mormoops blainvillii) foraged most in edge habitats, but differed in timing of peak activity. P. macleayii and M. blainvillii differed in diet, but low sample size precluded diet analysis for P. quadridens. High-intensity echolocating species that used longer, more narrowband signals and had longer, narrower wings (Molossus molossus, Tadarida brasiliensis) foraged most in open areas and differed in diet from the other species. Two disparate species were most active in clutter (dense vegetation). Pteronotus parnellii used high-duty-cycle echolocation apparently specialized for detecting fluttering targets in clutter. Macrotus waterhousii used low-intensity, broadband echolocation calls and presumably uses prey-generated sounds when foraging. These two species also differed in diet. Our data show that differences in morphology and echolocation behaviour coincide with differences in habitat use and diet, resulting in minimal overlap in resource use among species

    Toward a Unification of Star Formation Rate Determinations in the Milky Way and Other Galaxies

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    The star formation rate (SFR) of the Milky Way remains poorly known, with often-quoted values ranging from 1 to 10 solar masses per year. This situation persists despite the potential for the Milky Way to serve as the ultimate SFR calibrator for external galaxies. We show that various estimates for the Galactic SFR are consistent with one another once they have been normalized to the same initial mass function (IMF) and massive star models, converging to 1.9 +/- 0.4 M_sun/yr. However, standard SFR diagnostics are vulnerable to systematics founded in the use of indirect observational tracers sensitive only to high-mass stars. We find that absolute SFRs measured using resolved low/intermediate-mass stellar populations in Galactic H II regions are systematically higher by factors of ~2-3 as compared with calibrations for SFRs measured from mid-IR and radio emission. We discuss some potential explanations for this discrepancy and conclude that it could be allayed if (1) the power-law slope of the IMF for intermediate-mass (1.5 M_sun < m < 5 M_sun) stars were steeper than the Salpeter slope, or (2) a correction factor was applied to the extragalactic 24 micron SFR calibrations to account for the duration of star formation in individual mid-IR-bright H II regions relative to the lifetimes of O stars. Finally, we present some approaches for testing if a Galactic SFR of ~2 M_sun/yr is consistent with what we would measure if we could view the Milky Way as external observers. Using luminous radio supernova remnants and X-ray point sources, we find that the Milky Way deviates from expectations at the 1-3 sigma level, hinting that perhaps the Galactic SFR is overestimated or extragalactic SFRs need to be revised upwards.Comment: Accepted for publication in A

    The Balloon-Borne Large Aperture Submillimeter Telescope (BLAST) 2005: A 10 deg^2 Survey of Star Formation in Cygnus X

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    We present Cygnus X in a new multi-wavelength perspective based on an unbiased BLAST survey at 250, 350, and 500 micron, combined with rich datasets for this well-studied region. Our primary goal is to investigate the early stages of high mass star formation. We have detected 184 compact sources in various stages of evolution across all three BLAST bands. From their well-constrained spectral energy distributions, we obtain the physical properties mass, surface density, bolometric luminosity, and dust temperature. Some of the bright sources reaching 40 K contain well-known compact H II regions. We relate these to other sources at earlier stages of evolution via the energetics as deduced from their position in the luminosity-mass (L-M) diagram. The BLAST spectral coverage, near the peak of the spectral energy distribution of the dust, reveals fainter sources too cool (~ 10 K) to be seen by earlier shorter-wavelength surveys like IRAS. We detect thermal emission from infrared dark clouds and investigate the phenomenon of cold ``starless cores" more generally. Spitzer images of these cold sources often show stellar nurseries, but these potential sites for massive star formation are ``starless" in the sense that to date there is no massive protostar in a vigorous accretion phase. We discuss evolution in the context of the L-M diagram. Theory raises some interesting possibilities: some cold massive compact sources might never form a cluster containing massive stars; and clusters with massive stars might not have an identifiable compact cold massive precursor.Comment: 42 pages, 31 Figures, 6 table
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