2,912 research outputs found

    Brief Studies

    Get PDF
    Professor Gordon Rupp: The Optimism of Grace Toward Lutheran Unit

    El bosque petrificado Piedra Chamana

    Get PDF
    The Piedra Chamana Fossil Forest, near the village of Sexi in central Cajamarca, records the vegetation of the South American tropics 39 million years ago, early in the New World tropical forests history and before the rise of the present-day Andes. In this fossil forest, notable discoveries have included the mangrove genus Avicennia, a genus of emergent forest trees (Cynometra), and the second dipterocarp known from the New World. The significance of the fossils rests on the unique circumstances of preservation, the detailed reconstruction of the forest and environment that is possible based on the plant fossils and ancient soils, and the importance of this record for the study of climate change. Sites like the fossil forest are particularly vulnerable to disturbance and loss of the fossil resources. Ongoing monitoring shows that human activities and erosion are having serious effects and, conservation measures are urgently needed. The importance of the fossils for science, the beauty of this area of the Andes, and the potential of the site for education and tourism justify recognition of the fossil forest at an international level. The lowland tropical forest represented by the fossils is very different from the diverse broad-leaf sclerophyllous forest or woodland now growing in the area. Soil loss and erosion of the soft, porous volcanic substrate when the vegetation cover is disturbed poses a threat to both the native biota and the fossils. The conservation measures needed at the fossil site would have multiple benefits for the ecology of the region.El Bosque Petrificado Piedra Chamana, cerca del pueblo de Sexi en Cajamarca, registra la vegetación de los trópicos de Sudamérica de hace 39 millones de años, la que existió en los inicios de la historia de los bosques tropicales del Nuevo Mundo y antes del levantamiento de los Andes. En este bosque, descubrimientos notables incluyen el manglar del género Avicennia, un género de árboles forestales emergentes (Cynometra), y el segundo dipterocarp conocido del Nuevo Mundo. La importancia de los fósiles se basa en sus circunstancias únicas de preservación, es así como fósiles de plantas y suelos antiguos permiten la reconstrucción detallada del bosque y el medio ambiente en que existieron, contribuyendo con el conocimiento del cambio climático. Los sitios como este bosque fósil son muy vulnerables al disturbio y pérdida de los recursos fósiles. El monitoreo muestra que las actividades humanas y la erosión están teniendo efectos serios y que son necesarias medidas urgentes para su conservación. La importancia de los fósiles para la ciencia, la belleza de esta área de los Andes, y el potencial para la educación y turismo justifican el reconocimiento del Bosque Petrificado Piedra Chamana a nivel internacional. El bosque tropical representado por los fósiles es muy diferente del bosque diverso esclerófilo de hoja ancha que se encuentra actualmente en el sitio. La pérdida del suelo y la erosión del substrato suave y poroso por alteración de la cubierta vegetal son una amenaza para la biota nativa y los fósiles. Por lo tanto, las medidas de conservación necesarias para proteger los fósiles tendrían múltiples beneficios para la ecología del área

    El bosque petrificado de Piedra Chamana: preliminary paleoecological interpretations of a late middle Eocene fossil assemblage

    Get PDF
    The Piedra Chamana Fossil Forest in northern Peru, which is associated with Calipuy volcanics dated at 39 Ma, includes a large amount of fossil wood occurring across an 8-km-long area. In one part of the site, woods are weathering out of a volcanic mudflow (lahar) deposit and in growth position in an underlying ashfall that also contains fossil leaves. The general geologic context and inferred taphonomy of the fossils has been described in Woodcock et al, 2009. Recent fieldwork, and ongoing studies of the fossil material, has added to our understanding of the assemblage and also shown that fossil sites are more extensive than had been thought. Analysis of the fossils and their spatial occurrence indicates that three plant associations are represented at the sites we have studied most intensively (Fig. 1): • 1) Lowland tropical forest with a diversity of monocots and dicots. Preliminary study of the fossil woods indicates that a diversity of typically tropical taxa are represented. • 2) A back-mangrove or seasonally flooded association with the mangrove genus Avicennia and other taxa including palms. Avicennia is one of the commonest woods at the site and leaves of this genus are also found in the ashfall de posit • 3) Low diversity coastal/strand vegetation with Avicennia. Presence of Avicennia among both woods and leaves and morphological/anatomical analyses of the leaves and woods are consistent with dry conditions along the shore of the ocean embayment that extended into the continental interior during this period. Estimated specific gravity of the woods averages .50-.55, lower than the average for wet tropical forest, but the range of values (.33-.77) approaches that of lowland tropical forests generally. The fossils document uplift of -2600 m since the late middle Eocene and include a type of ecosystem (coastal mangrove) that is rarely p reserved in the rack record

    REMPI Spectroscopy of HfF

    Get PDF
    The spectrum of electronic states at 30000--33000 cm1^{-1} in hafnium fluoride has been studied using (1+1) resonance-enhanced multi-photon ionization (REMPI) and (1+1') REMPI. Six Ω=3/2\Omega' = 3/2 and ten Π1/2\Pi_{1/2} vibronic bands have been characterized. We report the molecular constants for these bands and estimate the electronic energies of the excited states using a correction derived from the observed isotope shifts. When either of two closely spaced Π1/2\Pi_{1/2} electronic states is used as an intermediate state to access autoionizing Rydberg levels, qualitatively distinct autoionization spectra are observed. The intermediate state-specificity of the autoionization spectra bodes well for the possibility of using a selected Π1/2\Pi_{1/2} state as an intermediate state to create ionic HfF+^+ in various selected quantum states, an important requirement for our electron electric dipole moment (eEDM) search in HfF+^+.Comment: 11 pages, 8 figures, 1 tabl

    Evaluation Research and Institutional Pressures: Challenges in Public-Nonprofit Contracting

    Get PDF
    This article examines the connection between program evaluation research and decision-making by public managers. Drawing on neo-institutional theory, a framework is presented for diagnosing the pressures and conditions that lead alternatively toward or away the rational use of evaluation research. Three cases of public-nonprofit contracting for the delivery of major programs are presented to clarify the way coercive, mimetic, and normative pressures interfere with a sound connection being made between research and implementation. The article concludes by considering how public managers can respond to the isomorphic pressures in their environment that make it hard to act on data relating to program performance.This publication is Hauser Center Working Paper No. 23. The Hauser Center Working Paper Series was launched during the summer of 2000. The Series enables the Hauser Center to share with a broad audience important works-in-progress written by Hauser Center scholars and researchers

    Central collisions of relativistic heavy ions

    Get PDF
    The energy spectra of protons and light nuclei produced by the interaction of 4He and 20Ne projectiles with Al and U targets have been investigated at incident energies ranging from 0.25 to 2.1 GeV per nucleon. Single fragment inclusive spectra have been obtained at angles between 25° and 150°, in the energy range from 30 to 150 MeV/nucleon. The multiplicity of intermediate and high energy charged particles was determined in coincidence with the measured fragments. In a separate study, fragment spectra were obtained in the evaporation energy range from 12C and 20Ne bombardment of uranium. We observe structureless, exponentially decaying spectra throughout the range of studied fragment masses. There is evidence for two major classes of fragments; one with emission at intermediate temperature from a system moving slowly in the lab frame, and the other with high temperature emission from a system propagating at a velocity intermediate between target and projectile. The high energy proton spectra are fairly well reproduced by a nuclear fireball model based on simple geometrical, kinematical, and statistical assumptions. Light cluster emission is also discussed in the framework of statistical models. NUCLEAR REACTIONS U(20Ne,X), E=250 MeV/nucl.; U(20Ne,X), U(α,X) E=400 MeV/nucl.; U(20Ne,X), Al(20Ne,X), E=2.1 GeV/nucl.; measured σ(E,θ), X=p, d, t, 3He,4He. U(20Ne,X), U(α,X), E=400 MeV/nucl.; U(20Ne,X), E=2.1 GeV/nucl.; measured σ(E, θ), Li to O. U(20Ne,X), U(12C,X), E=2.1 GeV/nucl.; measured σ(E, 90°), 4He to B. Nuclear fireballs, coalescence, thermodynamics of light nuclei production

    A Cross-Sectional Study of People with Epilepsy and Neurocysticercosis in Tanzania: Clinical Characteristics and Diagnostic Approaches.

    Get PDF
    Neurocysticercosis (NCC) is a major cause of epilepsy in regions where pigs are free-ranging and hygiene is poor. Pork production is expected to increase in the next decade in sub-Saharan Africa, hence NCC will likely become more prevalent. In this study, people with epilepsy (PWE, n=212) were followed up 28.6 months after diagnosis of epilepsy. CT scans were performed, and serum and cerebrospinal fluid (CSF) of selected PWE were analysed. We compared the demographic data, clinical characteristics, and associated risk factors of PWE with and without NCC. PWE with NCC (n=35) were more likely to be older at first seizure (24.3 vs. 16.3 years, p=0.097), consumed more pork (97.1% vs. 73.6%, p=0.001), and were more often a member of the Iraqw tribe (94.3% vs. 67.8%, p=0.005) than PWE without NCC (n=177). PWE and NCC who were compliant with anti-epileptic medications had a significantly higher reduction of seizures (98.6% vs. 89.2%, p=0.046). Other characteristics such as gender, seizure frequency, compliance, past medical history, close contact with pigs, use of latrines and family history of seizures did not differ significantly between the two groups. The number of NCC lesions and active NCC lesions were significantly associated with a positive antibody result. The electroimmunotransfer blot, developed by the Centers for Disease Control and Prevention, was more sensitive than a commercial western blot, especially in PWE and cerebral calcifications. This is the first study to systematically compare the clinical characteristics of PWE due to NCC or other causes and to explore the utility of two different antibody tests for diagnosis of NCC in sub-Saharan Africa

    An image dataset of cleared, x-rayed, and fossil leaves vetted to plant family for human and machine learning

    Get PDF
    Leaves are the most abundant and visible plant organ, both in the modern world and the fossil record. Identifying foliage to the correct plant family based on leaf architecture is a fundamental botanical skill that is also critical for isolated fossil leaves, which often, especially in the Cenozoic, represent extinct genera and species from extant families. Resources focused on leaf identification are remarkably scarce; however, the situation has improved due to the recent proliferation of digitized herbarium material, live-plant identification applications, and online collections of cleared and fossil leaf images. Nevertheless, the need remains for a specialized image dataset for comparative leaf architecture. We address this gap by assembling an open-access database of 30,252 images of vouchered leaf specimens vetted to family level, primarily of angiosperms, including 26,176 images of cleared and x-rayed leaves representing 354 families and 4,076 of fossil leaves from 48 families. The images maintain original resolution, have user-friendly filenames, and are vetted using APG and modern paleobotanical standards. The cleared and x-rayed leaves include the Jack A. Wolfe and Leo J. Hickey contributions to the National Cleared Leaf Collection and a collection of high-resolution scanned x-ray negatives, housed in the Division of Paleobotany, Department of Paleobiology, Smithsonian National Museum of Natural History, Washington D.C.; and the Daniel I. Axelrod Cleared Leaf Collection, housed at the University of California Museum of Paleontology, Berkeley. The fossil images include a sampling of Late Cretaceous to Eocene paleobotanical sites from the Western Hemisphere held at numerous institutions, especially from Florissant Fossil Beds National Monument (late Eocene, Colorado), as well as several other localities from the Late Cretaceous to Eocene of the Western USA and the early Paleogene of Colombia and southern Argentina. The dataset facilitates new research and education opportunities in paleobotany, comparative leaf architecture, systematics, and machine learning.Fil: Wilf, Peter. State University of Pennsylvania; Estados UnidosFil: Wing, Scott L.. National Museum of Natural History; Estados UnidosFil: Meyer, Herbert W.. State University of Pennsylvania; Estados UnidosFil: Rose, Jacob A.. State University of Pennsylvania; Estados UnidosFil: Saha, Rohit. State University of Pennsylvania; Estados UnidosFil: Serre, Thomas. State University of Pennsylvania; Estados UnidosFil: Cúneo, Néstor Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; ArgentinaFil: Donovan, Michael P.. State University of Pennsylvania; Estados UnidosFil: Erwin, Diane M.. State University of Pennsylvania; Estados UnidosFil: Gandolfo, María A.. Cornell University; Estados UnidosFil: González Akre, Erika. State University of Pennsylvania; Estados UnidosFil: Herrera, Fabiany. National Museum of Natural History; Estados UnidosFil: Hu, Shusheng. State University of Pennsylvania; Estados UnidosFil: Iglesias, Ari. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Johnson, Kirk R.. Smithsonian Tropical Research Institute; PanamáFil: Karim, Talia S.. University of Colorado; Estados UnidosFil: Zou, Xiaoyu. State University of Pennsylvania; Estados Unido

    Development and psychometric testing of an instrument to evaluate cognitive skills of evidence based practice in student health professionals

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Health educators need rigorously developed instruments to evaluate cognitive skills relating to evidence based practice (EBP). Previous EBP evaluation instruments have focused on the acquisition and appraisal of the evidence and are largely based in the medical profession. The aim of this study was to develop and validate an EBP evaluation instrument to assess EBP cognitive skills for entry-level health professional disciplines.</p> <p>Methods</p> <p>The Fresno test of competence in evidence based medicine was considered in the development of the 'Knowledge of Research Evidence Competencies' instrument (K-REC). The K-REC was reviewed for content validity. Two cohorts of entry-level students were recruited for the pilot study, those who had been exposed to EBP training (physiotherapy students, n = 24), and who had not been exposed to EBP training (human movement students, n = 76). The K-REC was administered to one cohort of students (n = 24) on two testing occasions to evaluate test-retest reliability. Two raters independently scored the first test occasion (n = 24) to evaluate the inter-rater reliability of the marking guidelines. Construct validity was assessed by comparison of the two groups, 'exposed' and 'non-exposed', and the percentage of students achieving a 'pass' score in each of these groups. Item difficulty was established.</p> <p>Results</p> <p>Among the 100 participants (24 EBP 'exposed', and 76 EBP 'non-exposed' students), there was a statistically significant (<it>p </it>< 0.0001) difference in the total K-REC scores. The test-retest and inter-rater reliability of the individual items and total scores ranged from moderate to excellent (measured by Cohen's Kappa and ICC, range: 0.62 to perfect agreement).</p> <p>Conclusions</p> <p>The K-REC instrument is a valid and reliable evaluation instrument of cognitive skills of EBP in entry-level student health professionals. The instrument is quick to disseminate and easy to score, making it a suitable instrument for health educators to employ to evaluate students' knowledge of EBP or in the evaluation of entry-level EBP training.</p

    Protest Cycles and Political Process: American Peace Movements in the Nuclear Age

    Full text link
    Since the dawn of the nuclear age small groups of activists have consistently protested both the content of United States national security policy, and the process by which it is made. Only occasionally, however, has concern about nuclear weapons spread beyond these relatively marginal groups, generated substantial public support, and reached mainstream political institutions. In this paper, I use histories of peace protest and analyses of the inside of these social movements and theoretical work on protest cycles to explain cycles of movement engagement and quiescence in terms of their relation to external political context, or the "structure of political opportunity." I begin with a brief review of the relevant literature on the origins of movements, noting parallels in the study of interest groups. Building on recent literature on political opportunity structure, I suggest a theoretical framework for understanding the lifecycle of a social movement that emphasizes the interaction between activist choices and political context, proposing a six-stage process through which challenging movements develop. Using this theoretical framework I examine the four cases of relatively broad antinuclear weapons mobilization in postwar America. I conclude with a discussion of movement cycles and their relation to political alignment, public policy, and institutional politics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68552/2/10.1177_106591299304600302.pd
    corecore