Review of \u3ci\u3e On Turner\u27s Trail: 100 Years of Writing Western History\u3c/i\u3e by Wilbur R. Jacobs

The addition of another study assessing the legacy of Frederick Jackson Turner will surely elicit a few groans among western scholars. This is too bad, for Wilbur Jacobs\u27 On Turner\u27s Trail is a detailed, insightful, and richly rewarding trek that should be undertaken by all western historians. Jacobs\u27 book mixes the best of biography, historiography, and institutional history, while adding a good deal of personal reminiscence as well. As a biography, Jacobs paints a portrait of an ambitious and complex historian, a man struggling to synthesize a huge quantity of data, who retains a genuinely open mind regarding material and methodology, but who increasingly defends his narrow frontier-sectional thesis in order to make sense of his data and to preserve his place in history. As historiography, Jacobs traces the roots of the frontier-sectional thesis in Turner\u27s childhood and education, follows its development and permutations during Turner\u27s life, reviews the life of the thesis in Turner\u27s students and disciples, especially through Frederick Merk and Ray Allen Billington, and brings the story down to the present day writings of Richard White and William Cronon. One of the most fascinating aspects of the book is Jacobs\u27 recreation of the institutional activities of these historians-course lectures which pass word-for-word from Turner to Merk to Billington, book reviews written to silence opposition to the frontier theory, and political battles waged over Turner\u27s legacy. Also interesting is the publication of responses to a survey regarding Turner from his former students. Readings these not only enhances Turner\u27s legacy, but also promotes self-reflection regarding the historian\u27s double role of researcher and teacher

The social system of the lava lizard, Microlophus atacamensis: the interplay between social structure and social organization

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author's publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Background Animal social systems can be described through four main components: social structure, social organization, mating system, and care system. Social structure describes the relationships between individuals in a population, while social organization describes the group composition, size, and spatiotemporal variation of a population. We use the frameworks of social structure and social organization to study the social system of Microlophus atacamensis, a lizard found in the rocky intertidal zone along the Chilean coast. The area M. atacamensis inhabits poses specific challenges stemming from their use of two distinct habitat types in the intertidal zone: they forage in the cool areas near the water’s edge and use large rocks in more inland areas for basking and refuge. Methods Our assessment of their social system focused on two separate populations: one to characterize social structure by means of focal observations and social network analysis, and a second to assess social organization via home range and core area analyses. Further, we examined the social system in two habitat types that comprise the intertidal zone: cobble fields and interspersed large rocks. Results Social network analysis revealed an interconnected network with a few highly central individuals. Body size influenced the outcomes of aggressive interactions, with interactions being more common in cobble fields where males had more associates and more repeated interactions than females. Spatial analyses revealed that the social organization of M. atacamensis is characterized by (1) high home range overlap, specifically in the cobble fields and (2) relatively exclusive core areas dispersed across both habitat types. Conclusion A social system is composed of both cooperative and competitive behaviors. While our study focused on competitive interactions, the extent and influence of cooperative behaviors is still unclear and merits future research. We suggest that M. atacamensis has a variable social system in which territoriality on large rocks affects access to stationary resources in that habitat (e.g., basking sites and refuges), while competition in the cobble fields could lay the foundation for a system of dominance relationships controlling access to variable food resources in cobble field areas of the intertidal zone

Evidence for Dynamically Driven Formation of the GW170817 Neutron Star Binary in NGC 4993

We present a study of NGC 4993, the host galaxy of the GW170817 gravitational-wave event, the GRB 170817A short gamma-ray burst (sGRB), and the AT 2017gfo kilonova. We use Dark Energy Camera imaging, AAT spectra, and publicly available data, relating our findings to binary neutron star (BNS) formation scenarios and merger delay timescales. NGC 4993 is a nearby early-type galaxy, with an i-band Sérsic index n = 4.0 and low asymmetry (A = 0.04 ± 0.01). These properties are unusual for sGRB hosts. However, NGC 4993 presents shell-like structures and dust lanes indicative of a recent galaxy merger, with the optical transient located close to a shell. We constrain the star formation history (SFH) of the galaxy assuming that the galaxy merger produced a star formation burst, but find little to no ongoing star formation in either spatially resolved broadband SED or spectral fitting. We use the best-fit SFH to estimate the BNS merger rate in this type of galaxy, as R^(gal)_(NSM) = 5.7^(+0.57)_(-3.3) x 10^(-6) yr^(-1). If star formation is the only considered BNS formation scenario, the expected number of BNS mergers from early-type galaxies detectable with LIGO during its first two observing seasons is 0.038^(+0.004)_(-0.022), as opposed to ~0.5 from all galaxy types. Hypothesizing that the binary formed due to dynamical interactions during the galaxy merger, the subsequent time elapsed can constrain the delay time of the BNS coalescence. By using velocity dispersion estimates and the position of the shells, we find that the galaxy merger occurred t_(mer) ≾ 200 Myr prior to the BNS coalescence

Detection of Cross-Correlation between Gravitational Lensing and γ Rays

In recent years, many γ-ray sources have been identified, yet the unresolved component hosts valuable information on the faintest emission. In order to extract it, a cross-correlation with gravitational tracers of matter in the Universe has been shown to be a promising tool. We report here the first identification of a cross-correlation signal between γ rays and the distribution of mass in the Universe probed by weak gravitational lensing. We use data from the Dark Energy Survey Y1 weak lensing data and the Fermi Large Area Telescope 9-yr γ-ray data, obtaining a signal-to-noise ratio of 5.3. The signal is mostly localized at small angular scales and high γ-ray energies, with a hint of correlation at extended separation. Blazar emission is likely the origin of the small-scale effect. We investigate implications of the large-scale component in terms of astrophysical sources and particle dark matter emission

The Splashback Feature around DES Galaxy Clusters: Galaxy Density and Weak Lensing Profiles

Splashback refers to the process of matter that is accreting onto a dark matter halo reaching its first orbital apocenter and turning around in its orbit. The clustercentric radius at which this process occurs, r_(sp), defines a halo boundary that is connected to the dynamics of the cluster. A rapid decline in the halo profile is expected near r_(sp). We measure the galaxy number density and weak lensing mass profiles around REDMAPPER galaxy clusters in the first-year Dark Energy Survey (DES) data. For a cluster sample with mean M_(200m) mass ≈2.5 × 10^(14) M⊙, we find strong evidence of a splashback-like steepening of the galaxy density profile and measure r_(sp) = 1.13 ± 0.07 h^(−1) Mpc, consistent with the earlier Sloan Digital Sky Survey measurements of More et al. and Baxter et al. Moreover, our weak lensing measurement demonstrates for the first time the existence of a splashback-like steepening of the matter profile of galaxy clusters. We measure r_(sp) = 1.34 ± 0.21 h^(−1) Mpc from the weak lensing data, in good agreement with our galaxy density measurements. For different cluster and galaxy samples, we find that, consistent with ΛCDM simulations, r_(sp) scales with R_(200m) and does not evolve with redshift over the redshift range of 0.3–0.6. We also find that potential systematic effects associated with the REDMAPPER algorithm may impact the location of r_(sp). We discuss the progress needed to understand the systematic uncertainties and fully exploit forthcoming data from DES and future surveys, emphasizing the importance of more realistic mock catalogs and independent cluster samples

Análise estatística de parâmetros de pneus com base em amostra da frota de Joinville/SC

TCC (graduação) - Universidade Federal de Santa Catarina. Campus Joinville. Engenharia Automotiva.No estudo do comportamento dinâmico de um veículo, toda transmissão de forças entre o veículo e o solo ocorre por meio da área de contato do pneu com a pista. A manutenção deste contato durante a direção permite que condutor possua controle sobre o veículo, sendo esta, uma das premissas para a segurança veicular. Os sulcos presentes na banda de rodagem colaboram para que o atrito entre a borracha e o agregado do solo seja mantido em diferentes condições de pista, seja ela seca, molhada, limpa ou suja. Sua profundidade é uma grandeza fácil de ser medida, sendo regulamentada no Brasil pelo CONTRAN em, no mínimo, 1,6 mm. Entretanto, existem poucos estudos quantitativos sobre o estado de conservação dos pneus atualmente em uso na frota brasileira. Este trabalho buscou analisar, por meio de ferramentas estatísticas, informações sobre a profundidade de sulco de pneus com foco na população de veículos da cidade de Joinville, estado de Santa Catarina. Com a utilização de um profundímetro, a profundidade de sulco foi medida diretamente nos pneus da amostra, formada por veículos de passeio. Os resultados permitiram produzir um panorama do estado de conservação dos pneus da frota, conhecer a profundidade de sulco mínima, média e máxima. Com posse de tais informações foi possível ainda identificar o fabricante e o modelo de pneu com maior parcela de mercado para cada categoria analisada

Cosmic shear analysis of archival HST/ACS data: I. Comparison of early ACS pure parallel data to the HST/GEMS Survey

This is the first paper of a series describing our measurement of weak lensing by large-scale structure using archival observations from the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope (HST). In this work we present results from a pilot study testing the capabilities of the ACS for cosmic shear measurements with early parallel observations and presenting a re-analysis of HST/ACS data from the GEMS survey and the GOODS observations of the Chandra Deep Field South (CDFS). We describe our new correction scheme for the time-dependent ACS PSF based on observations of stellar fields. This is currently the only technique which takes the full time variation of the PSF between individual ACS exposures into account. We estimate that our PSF correction scheme reduces the systematic contribution to the shear correlation functions due to PSF distortions to < 2*10^{-6} for galaxy fields containing at least 10 stars. We perform a number of diagnostic tests indicating that the remaining level of systematics is consistent with zero for the GEMS and GOODS data confirming the success of our PSF correction scheme. For the parallel data we detect a low level of remaining systematics which we interpret to be caused by a lack of sufficient dithering of the data. Combining the shear estimate of the GEMS and GOODS observations using 96 galaxies arcmin^{-2} with the photometric redshift catalogue of the GOODS-MUSIC sample, we determine a local single field estimate for the mass power spectrum normalisation sigma_{8,CDFS}=0.52^{+0.11}_{-0.15} (stat) +/- 0.07 (sys) (68% confidence assuming Gaussian cosmic variance) at fixed Omega_m=0.3 for a LambdaCDM cosmology. We interpret this exceptionally low estimate to be due to a local under-density of the foreground structures in the CDFS.Comment: Version accepted for publication in Astronomy & Astrophysics with 28 pages, 25 figures. A version with full resolution figures can be downloaded from http://www.astro.uni-bonn.de/~schrabba/papers/cosmic_shear_acs1_v2.pd

Design of a Curriculum-Spanning Mechanical Engineering Laboratory Experiment

This paper describes a laboratory experiment that was designed to facilitate education in material science, instrumentation and controls, and thermal sciences. The laboratory module is part of a broader effort to enhance mechanical engineering laboratory curriculum to incorporate modern pedagogical methods and to improve a defined set of student outcomes. The laboratory experiment focuses on a low-cost toaster oven that has been modified to allow students to control temperature and fan operation through either LabVIEW or Arduino systems. The oven experiment has been designed to facilitate long-term testing in the material science laboratory, sensing and control of the temperature in the oven during the mechanical systems laboratory, and precise heating of specimens during the senior level thermal systems laboratory. To assess the effectiveness of the laboratory experiment a student survey was administered and results indicate the new laboratory experiment has been successful in improving student engagement