213 research outputs found

    A Milliped New to Michigan (Pselaphognatha: Polyxenus)

    Get PDF
    The authors wish to report the finding of representatives of the genus Polyxenus for the first time in Michigan (Fig. 1). In Bert M. Johnson\u27s survey (1954) of the millipedes of Michigan, no members of the subclass Pselaphognatha were reported. During the period of September through October 1970, the authors collected over 40 specimens of Polyxenus and observed over 100 in the field. All of the specimens were found in a mature pine stand in Ypsilanti Township

    Using Ecological Data as a Foundation for Decision-Making in the USA

    Get PDF
    Decisions that impact the quality of aquatic systems are being made daily throughout the world based on little or no ecological information (Barbour et al., 2004). Monitoring information, based on scientifically and rigorously tested ecological indicators, is integral to water quality management programs for protecting human health, preserving and restoring ecosystem integrity, and sustaining a viable economy. Under the Clean Water Act of the United States, water quality agencies of the states and tribes are required to conduct monitoring and assessment to address the mandates of the law. However, recent critiques of water monitoring programs have claimed that the United States Environmental Protection Agency (U.S. EPA) and State water quality agencies cannot make statistically valid inferences about water quality and the condition of the Nation's waters, i.e., whether they are improving, degrading or remaining the same; furthermore, we lack data to support management decisions regarding the Nation's aquatic resources. The National Wadeable Streams Assessment Program (WSA) was established in early 2004 to answer the question of what is the status of the Nation's waters, and to maximize partnerships among U.S. EPA, States and Tribes, and other agencies to establish a framework to address issues at state and local scales. Ecological data in any form require some measure of translation to be useable by the environmental manager, i.e., a hierarchy exists in the translation process from basic biological data in its rawest form through a series of manipulations in the analysis phase to reporting of the results and interpretation. This nationally focused program is a step towards ensuring adequate monitoring data exist in the future to assess water quality and make sound watershed management decisions throughout the USA; actions are taken to protect and restore water quality that maximize benefits and minimize costs; and sound science forms the basis of making informed decisions regarding our aquatic resource.Diariamente se están tomando decisiones que inciden en la calidad de los sistemas acuáticos basadas en escasa o ninguna información ecológica (Barbour et al., 2004). La información obtenida en programas de gestión, basada en indicadores cient'ıficos y basados en indicadores ecológicos, se integra en programas de gestión de la calidad del agua para la protección de la salud humana, la preservación o restauración de la integridad de los ecosistemas y el sostenimiento de una economía viable. Por mandato del Acta sobre el Agua Limpia de los Estados Unido, se han creado agencias a nivel de Estados o regiones para realizar programas de estudio y gestión para cumplir el mandato de la ley. No obstante, recientemente han surgido críticas a los programas de gestión señalando que la Agencia de Protección Ambiental de los Estados Unidos (U.S. EPA) y las agencias de calidad del agua estatales no pueden realizar inferencias estadísticamente válidas acerca de la calidad del agua y de la situación de las aguas de la nación, p. e. si estan mejorando, degradando o permanecen igual. Además, no tenemos datos para apoyar las decisiones de gestión en relación con los recursos acuáticos nacionales. El Programa de Estudio de los Ríos Vadeables (WSA) se estableció en 2004 para responder a la pregunta de cual es la situación de las aguas de la nación, y para maximizar la colaboración entre U.S. EPA, y las agencias estatales, locales y similares para realizar un marco de trabajo que permita establecer los objetivos a escalas estatal y local. La información ecológica de cualquier tipo requiere algunas medidas de traducción para que sea utilizable por los gestores ambientales, p. e. existe una jerarquía en el proceso de traslación desde datos biológicos básicos, en su forma poco elaborada, hasta una serie de manipulaciones en la fase de análisis para los informes de resultados y su interpretación. Este programa enfocado a nivel nacional es un paso para asegurar que existen datos adecuados de gestión a través de todo el país. Se están realizando actuaciones para proteger y mejorar la calidad del agua que maximice los beneficios y minimice los costes a la vez que establezcan las bases científicas para tomar decisiones teniendo en cuenta nuestros recursos acuáticos

    Pathologies of Quenched Lattice QCD at non--zero Density and its Effective Potential

    Get PDF
    We simulate lattice QCD at non--zero baryon density and zero temperature in the quenched approximation, both in the scaling region and in the infinite coupling limit. We investigate the nature of the forbidden region -- the range of chemical potential where the simulations grow prohibitively expensive, and the results, when available, are puzzling if not unphysical. At weak coupling we have explored the sensitivity of these pathologies to the lattice size, and found that using a large lattice (64×16364 \times 16^3) does not remove them. The effective potential sheds considerable light on the problems in the simulations, and gives a clear interpretation of the forbidden region. The strong coupling simulations were particularly illuminating on this point.Comment: 49 pages, uu-encoded expanding to postscript;also available at ftp://hlrz36.hlrz.kfa-juelich.de/pub/mpl/hlrz72_95.p

    Nucleons or diquarks? Competition between clustering and color superconductivity in quark matter

    Get PDF
    We study the instabilities of quark matter in the framework of a generalized Nambu--Jona-Lasinio model, in order to explore possible competition between three-quark clustering to form nucleons and diquark formation leading to color superconductivity. Nucleon and Δ\Delta solutions are obtained for the relativistic Faddeev equation at finite density and their binding energies are compared with those for the scalar and axial-vector diquarks found from the Bethe-Salpeter equation. In a model with interactions in both scalar and axial diquark channels, bound nucleons exist up to nuclear matter density. However, except at densities below about a quarter of that of nuclear matter, we find that scalar diquark formation is energetically favored. This raises the question of whether a realistic phase diagram of baryonic matter can be obtained from any model which does not incorporate color confinement.Comment: 23 pages (RevTeX), 5 figures (epsf

    Non-Equilibrium Statistical Physics of Currents in Queuing Networks

    Get PDF
    We consider a stable open queuing network as a steady non-equilibrium system of interacting particles. The network is completely specified by its underlying graphical structure, type of interaction at each node, and the Markovian transition rates between nodes. For such systems, we ask the question ``What is the most likely way for large currents to accumulate over time in a network ?'', where time is large compared to the system correlation time scale. We identify two interesting regimes. In the first regime, in which the accumulation of currents over time exceeds the expected value by a small to moderate amount (moderate large deviation), we find that the large-deviation distribution of currents is universal (independent of the interaction details), and there is no long-time and averaged over time accumulation of particles (condensation) at any nodes. In the second regime, in which the accumulation of currents over time exceeds the expected value by a large amount (severe large deviation), we find that the large-deviation current distribution is sensitive to interaction details, and there is a long-time accumulation of particles (condensation) at some nodes. The transition between the two regimes can be described as a dynamical second order phase transition. We illustrate these ideas using the simple, yet non-trivial, example of a single node with feedback.Comment: 26 pages, 5 figure

    Prevalence of concomitant rheumatologic diseases and autoantibody specificities among racial and ethnic groups in SLE patients

    Get PDF
    Objective: Leveraging the Manhattan Lupus Surveillance Program (MLSP), a population-based registry of cases of systemic lupus erythematosus (SLE) and related diseases, we investigated the proportion of SLE with concomitant rheumatic diseases, including Sjögren’s disease (SjD), antiphospholipid syndrome (APLS), and fibromyalgia (FM), as well as the prevalence of autoantibodies in SLE by sex and race/ethnicity. Methods: Prevalent SLE cases fulfilled one of three sets of classification criteria. Additional rheumatic diseases were defined using modified criteria based on data available in the MLSP: SjD (anti-SSA/Ro positive and evidence of keratoconjunctivitis sicca and/or xerostomia), APLS (antiphospholipid antibody positive and evidence of a blood clot), and FM (diagnosis in the chart). Results: 1,342 patients fulfilled SLE classification criteria. Of these, SjD was identified in 147 (11.0%, 95% CI 9.2–12.7%) patients with women and non-Latino Asian patients being the most highly represented. APLS was diagnosed in 119 (8.9%, 95% CI 7.3–10.5%) patients with the highest frequency in Latino patients. FM was present in 120 (8.9%, 95% CI 7.3–10.5) patients with non-Latino White and Latino patients having the highest frequency. Anti-dsDNA antibodies were most prevalent in non-Latino Asian, Black, and Latino patients while anti-Sm antibodies showed the highest proportion in non-Latino Black and Asian patients. Anti-SSA/Ro and anti-SSB/La antibodies were most prevalent in non-Latino Asian patients and least prevalent in non-Latino White patients. Men were more likely to be anti-Sm positive. Conclusion: Data from the MLSP revealed differences among patients classified as SLE in the prevalence of concomitant rheumatic diseases and autoantibody profiles by sex and race/ethnicity underscoring comorbidities associated with SLE

    Exploring medical student learning in the large group teaching environment: examining current practice to inform curricular development

    Get PDF
    Background Lectures continue to be an efficient and standardised way to deliver information to large groups of students. It has been well documented that students prefer interactive lectures, based on active learning principles, to didactic teaching in the large group setting. Despite this, it is often the case than many students do not engage with active learning tasks and attempts at interaction. By exploring student experiences, expectations and how they use lectures in their learning we will provide recommendations for faculty to support student learning both in the lecture theatre and during personal study time. Methods This research employed a hermeneutic phenomenological approach. Three focus groups, consisting of 19 students in total, were used to explore the experiences of second year medical students in large group teaching sessions. Using generic thematic data analysis, these accounts have been developed into a meaningful account of experience. Results This study found there to be a well-established learning culture amongst students and with it, expectations as to the format of teaching sessions. Furthermore, there were set perceptions about the student role within the learning environment which had many implications, including the way that innovative teaching methods were received. Student learning was perceived to take place outside the lecture theatre, with a large emphasis placed on creating resources that can be taken away to use in personal study time. Conclusions Presented here is a constructive review of reasons for student participation, interaction and engagement in large group teaching sessions. Based on this are recommendations constructed with the view to aid educators in engaging students within this setting. Short term, educators can implement strategies that monopolise on the established learning culture of students to encourage engagement with active learning strategies. Long term, it would be beneficial for educators to consider ways to shift the current student learning culture to one that embraces an active learning curriculum

    Instantons and the Chiral Phase Transition at non-zero Baryon Density

    Get PDF
    We study an interacting ensemble of instantons at finite baryon chemical potential. We emphasize the importance of fermionic zero modes and calculate the fermion induced interaction between instantons at non-zero chemical potential. We show that unquenched simulations of the instanton ensemble are feasible in two regimes, for sufficiently small and for very large chemical potential. At very large chemical potential chiral symmetry is restored and the instanton ensemble is dominated by strongly correlated chain-like configurations.Comment: 37 pages, 10 figures, uses revtex, revised version (minor corrections and expanded dicussion

    Creationism and Intelligent Design

    Get PDF
    Until recently, little attention has been paid in the school classroom to creationism and almost none to intelligent design. However, creationism and intelligent design appear to be on the increase and there are indications that there are more countries in which schools are becoming battlegrounds over them. I begin by examining whether creationism and intelligent design are controversial issues, drawing on Robert Dearden’s epistemic criterion of the controversial and more recent responses to and defences of this. I then examine whether the notion of ‘worldviews’ in the context of creationism is a useful one by considering the film March of the Penguins. I conclude that the ‘worldviews’ perspective on creationism is useful for two reasons: first, it indicates the difficulty of using the criterion of reason to decide whether an issue is controversial or not; secondly, it suggests that standard ways of addressing the diversity of student views in a science classroom may be inadequate. I close by examining the implications of this view for teaching in science lessons and elsewhere, for example in religious education lessons and at primary level where subject divisions cannot be made in so clear-cut a manner
    corecore