2,011 research outputs found

    Properties of Factorial Cumulant to Factorial Moment Ratio

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    It is shown that the ratio of factorial cumulant moments to factorial moments for a multiplicity distribution truncated in the tail reveals oscillations in sign similar to those observed in experimental data. It is suggested that this effect be taken into account in the analysis of data in order to obtain correct physical information on the multiplicity distributions.Comment: (LaTeX + epsfig, 8 pages including 3 PostScript figures, all encoded via uufiles), DFTT 46/9

    An SU(3) model for octet baryon and meson fragmentation

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    The production of the octet of baryons and mesons in e^+ e^- collisions is analysed, based on considerations of SU(3) symmetry and a simple model for SU(3) symmetry breaking in fragmentation functions. All fragmentation functions, D_q^h(x, Q^2), describing the fragmentation of quarks into a member of the baryon octet (and similarly for fragmentation into members of the meson octet) are expressed in terms of three SU(3) symmetric functions, \alpha(x, Q^2), \beta(x, Q^2), and \gamma(x, Q^2). With the introduction of an SU(3) breaking parameter, \lambda, the model is successful in describing hadroproduction data at the Z pole. The fragmentation functions are then evolved using leading order evolution equations and good fits to currently available data at 34 GeV and at 161 GeV are obtained.Comment: 24 pages LaTeX file including 11 postscript figure file

    Heavy Flavour Production in Two-Photon Collisions

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    We review the production of charm and bottom quarks in two-photon collisions at e+e- colliders. The next-to-leading order QCD predictions for total cross sections and differential distributions are compared with recent experimental results.Comment: 6 pages, 2 figures. Talk given at the UK Phenomenology Workshop on Collider Physics, Durham, England, 19-24 Sep 199

    MTSS1 is a critical epigenetically regulated tumor suppressor in CML

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    Chronic myeloid leukemia (CML) is driven by malignant stem cells that can persist despite therapy. We have identified Metastasis suppressor 1 (Mtss1/MIM) to be downregulated in hematopoietic stem and progenitor cells from leukemic transgenic SCLtTA/Bcr-Abl mice and in patients with CML at diagnosis, and Mtss1 was restored when patients achieved complete remission. Forced expression of Mtss1 decreased clonogenic capacity and motility of murine myeloid progenitor cells and reduced tumor growth. Viral transduction of Mtss1 into lineage depleted SCLtTA/Bcr-Abl bone marrow cells decreased leukemic cell burden in recipients, and leukemogenesis was reduced upon injection of Mtss1 overexpressing murine myeloid 32D cells. Tyrosine kinase inhibitor (TKI) therapy and reversion of Bcr-Abl expression increased Mtss1 expression but failed to restore it to control levels. CML patient samples revealed higher DNA methylation of specific Mtss1 promoter CpG sites that contain binding sites for Kaiso and Rest transcription factors. In summary, we identified a novel tumor suppressor in CML stem cells that is downregulated by both Bcr-Abl kinase-dependent and -independent mechanisms. Restored Mtss1 expression markedly inhibits primitive leukemic cell biology in vivo, providing a therapeutic rationale for the Bcr-Abl-Mtss1 axis to target TKI resistant CML stem cells in patients

    Large-Area Scintillator Hodoscope with 50 ps Timing Resolution Onboard BESS

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    We describe the design and performance of a large-area scintillator hodoscope onboard the BESS rigidity spectrometer; an instrument with an acceptance of 0.3 m^{2}sr. The hodoscope is configured such that 10 and 12 counters are respectively situated in upper and lower layers. Each counter is viewed from its ends by 2.5 inch fine-mesh photomultiplier tubes placed in a stray magnetic field of 0.2 Tesla. Various beam-test data are presented. Use of cosmic-ray muons at ground-level confirmed 50 ps timing resolution for each layer, giving an overall time-of-flight resolution of 70 ps rms using a pure Gaussian resolution function. Comparison with previous measurements on a similar scintillator hodoscope indicates good agreement with the scaling law that timing resolution is proportional to 1/Npe\sqrt{N_{\rm pe}}, where NpeN_{\rm pe} is the effective number of photoelectrons.Comment: 16 pages, 14 figure

    American Society for Parenteral and Enteral Nutrition Guidelines for the Selection and Care of Central Venous Access Devices for Adult Home Parenteral Nutrition Administration

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    This document represents the American Society for Parenteral and Enteral Nutrition (ASPEN) clinical guidelines to describe best practices in the selection and care of central venous access devices (CVADs) for the infusion of home parenteral nutrition (HPN) admixtures in adult patients. The guidelines targeted adults >18 years of age in which the intervention or exposure had to include HPN that was administered via a CVAD. Case studies, non‐English studies, or studies of CVAD no longer available in the United States were excluded. In total, 564 abstract citations, 350 from Medline and 214 from PubMed/non‐MEDLINE databases, were scanned for relevance. Of the 564 citations, 13 studies addressed at least 1 of the 6 guideline‐related questions, and none of the studies were prospective and randomized. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria were used to adjust the evidence grade based on assessment of the quality of study design and execution. Recommendations for the CVAD type, composition, or number of lumens to minimize infectious or mechanical complications are based on a limited number of studies and expert opinion of the authors, all very experienced in home infusion therapy. No studies were found that compared best solutions for routine flushing of lumens (eg, heparin versus saline) or for maintaining catheters in situ while treating CVAD mechanical or infectious complications. It is clear that studies to answer these questions are very limited, and further research is needed. These clinical guidelines were approved by the ASPEN Board of Directors.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147811/1/jpen1455_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147811/2/jpen1455.pd

    Superconformal constraints for QCD conformal anomalies

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    Anomalous superconformal Ward identities and commutator algebra in N = 1 super-Yang-Mills theory give rise to constraints between the QCD special conformal anomalies of conformal composite operators. We evaluate the superconformal anomalies that appear in the product of renormalized conformal operators and the trace anomaly in the supersymmetric spinor current and check the constraints at one-loop order. In this way we prove the universality of QCD conformal anomalies, which define the non-diagonal part of the anomalous dimension matrix responsible for scaling violations of exclusive QCD amplitudes at the next-to-leading order.Comment: 30 pages, 2 figures, LaTe

    Relationship Between Spirituality, Meaning in Life, Psychological Distress, Wish for Hastened Death, and Their Influence on Quality of Life in Palliative Care Patients.

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    Spiritual, existential, and psychological issues represent central components of quality of life (QOL) in palliative care. A better understanding of the dynamic nature underlying these components is essential for the development of interventions tailored to the palliative context. The aims were to explore 1) the relationship between spirituality, meaning in life, wishes for hastened death and psychological distress in palliative patients and 2) the extent to which these nonphysical determinants influence QOL. A cross-sectional study involving face-to-face interviews with Swiss palliative patients was performed, including the Schedule for Meaning in Life Evaluation (SMILE), the Functional Assessment of Chronic Illness Therapy-Spiritual Well-Being Scale (FACIT-Sp), the Idler Index of Religiosity (IIR), the Hospital Anxiety and Depression Scale (HADS), and the Schedule of Attitudes toward Hastened Death (SAHD). QOL was measured with a single-item visual analogue scale (0-10). Two hundred and six patients completed the protocol (51.5% female; mean age = 67.5 years). The results indicated a significant negative relationship between FACIT-Sp/SMILE and HADS total scores (P = 0.000). The best model for QOL explained 32.8% of the variance (P = 0.000) and included the FACIT-Sp, SMILE, and SAHD total scores, the IIR "private religiosity" score, as well as the HADS "depression" score. Both spiritual well-being and meaning in life appear to be potential protective factors against psychological distress at the end of life. Since nonphysical determinants play a major role in shaping QOL at the end of life, there is a need for the development of meaning-oriented and spiritual care interventions tailored to the fragility of palliative patients

    Multiplicity distributions inside parton cascades developing in a medium

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    The explanation of the suppression of high-pT hadron yields at RHIC in terms of jet-quenching implies that the multiplicity distributions of particles inside a jet and jet-like particle correlations differ strongly in nucleus-nucleus collisions at RHIC or at the LHC from those observed at e+e- or hadron colliders. We present a framework for describing the medium-induced modification, which has a direct interpretation in terms of a probabilistic medium-modified parton cascade, and which treats leading and subleading partons on an equal footing. We show that our approach can account for the strong suppression of single inclusive hadron spectra measured in Au-Au collisions at RHIC, and that this implies a characteristic distortion of the single inclusive distribution of soft partons inside the jet. We determine, as a function of the jet energy, to what extent the soft fragments within a jet can be measured above some momentum cut.Comment: 5 pages, 4 eps-figures; talk given at Hot Quarks 2006, Villasimius (Sardinia, Italy), May 15-20, 200

    Superposition effect and clan structure in forward-backward multiplicity correlations

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    The main purpose of this paper is to discuss the link between forward-backward multiplicity correlations properties and the shape of the corresponding final charged particle multiplicity distribution in various classes of events in different collisions. It is shown that the same mechanism which explains the shoulder effect and the H_n vs. n oscillations in charged particle multiplicity distributions, i.e., the weighted superposition of different classes of events with negative binomial properties, reproduces within experimental errors also the forward-backward multiplicity correlation strength in e+e- annihilation at LEP energy and allows interesting predictions for pp collisions in the TeV energy region, to be tested at LHC, for instance with the ALICE detector. We limit ourselves at present to study substructures properties in hadron-hadron collisions and e+e- annihilation; they are examined as ancillary examples in the conviction that their understanding might be relevant also in other more complex cases.Comment: 16 page
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