7,484 research outputs found

    Ixodes brunneus (Acari: Ixodidae) from Two Bird Hosts: A New Michigan Tick

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    The tick Ixodes brunneus Koch (Acari: Ixodidae) is reported for the first time in Michigan from two bird hosts at two locations in the lower peninsula. All stages of this tick exclusively feed on birds, and are primarily known from the southern U.S., although abundant records occur from northern states. The role of this species as a vector of pathogens is discussed

    Trions in a periodic potential

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    The group-theoretical classification of trion states is presented. It is based on considerations of products of irreducible representations of the 2D translation group. For a given BvK period N degeneracy of obtained states is N^2. Trions consist of two identical particles so the symmetrization of states with respect to particles transposition is considered. Completely antisymmetric states can be constructed by introducing antisymmetric spin functions. Two symmetry adapted bases are considered. The third possibility is postponed for the further investigations.Comment: revtex, 5 p., sub. to Physica

    Exploring the Lived Experiences of Adults Who Stutter: A Qualitative Study

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    Stuttering is a phenomenon that affects millions of people worldwide, and up until now the disorder has most often been portrayed in a negative light. The purpose of this study was to understand the lived experiences of young adults who stutter, framing the research with a more holistic perspective. Two participants were interviewed in depth using a qualitative research approach to explore what it is like to live with stuttering and how it has affected their daily lives. Literature to date tends to group people who stutter into quantitative studies that problematize the disorder (Blood, G., Blood, I.M., Maloney, K., Meyer, C. & Qualls, C.D., 2007). Conversely, this research is presented in the form of a narrative inquiry, because the focus of the study was to highlight two individuals’ lives as a holistic picture, rather than just focus on the negative outcomes of stuttering. The results show that living with a stutter is challenging, but the research is also likely to better inform readers about the impact of stuttering and possible positive and/or negative outcomes. Exploring the experience of stuttering from this perspective will benefit the speech-language pathology community to gain client perspective, as well as help others to understand this speech disorder from a more personal perspective

    Quantum Gravitational Bremsstrahlung, Massless versus Massive Gravity

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    The massive spin-2 quantum gauge theory previously developed is applied to calculate gravitational bremsstrahlung. It is shown that this theory is unique and free from defects. In particular, there is no strong coupling if the graviton mass becomes small. The cross sections go over smoothly into the ones of the massless theory in the limit of vanishing graviton mass. The massless cross sections are calculated for the full tensor theory.Comment: 13 pages, 1 figur

    The Standard Model and its Generalizations in Epstein-Glaser Approach to Renormalization Theory II: the Fermion Sector and the Axial Anomaly

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    We complete our study of non-Abelian gauge theories in the framework of Epstein-Glaser approach to renormalization theory including in the model an arbitrary number of Dirac Fermions. We consider the consistency of the model up to the third order of the perturbation theory. In the second order we obtain pure group theoretical relations expressing a representation property of the numerical coefficients appearing in the left and right handed components of the interaction Lagrangian. In the third order of the perturbation theory we obtain the the condition of cancellation of the axial anomaly.Comment: 38 pages, LATEX 2e, extensive rewritting, some errors eliminate

    A possible dearth of hot gas in galaxy groups at intermediate redshift

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    We examine the X-ray luminosity of galaxy groups in the CNOC2 survey, at redshifts 0.1 < z < 0.6. Previous work examining the gravitational lensing signal of the CNOC2 groups has shown that they are likely to be genuine, gravitationally bound objects. Of the 21 groups in the field of view of the EPIC-PN camera on XMM-Newton, not one was visible in over 100 ksec of observation, even though three of the them have velocity dispersions high enough that they would easily be visible if their luminosities scaled with their velocity dispersions in the same way as nearby groups' luminosities scale. We consider the possibility that this is due to the reported velocity dispersions being erroneously high, and conclude that this is unlikely. We therefore find tentative evidence that groups at intermediate redshift are underluminous relative to their local cousins.Comment: 16 pages, 5 figures, reference added in section 1, typos corrected, published in Ap

    The Interaction of Quantum Gravity with Matter

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    The interaction of (linearized) gravitation with matter is studied in the causal approach up to the second order of perturbation theory. We consider the generic case and prove that gravitation is universal in the sense that the existence of the interaction with gravitation does not put new constraints on the Lagrangian for lower spin fields. We use the formalism of quantum off-shell fields which makes our computation more straightforward and simpler.Comment: 25 page
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