338 research outputs found

    Anatomy of the Soft-Photon Approximation in Hadron-Hadron Bremsstrahlung

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    A modified Low procedure for constructing soft-photon amplitudes has been used to derive two general soft-photon amplitudes, a two-s-two-t special amplitude MμTsTtsM^{TsTts}_{\mu} and a two-u-two-t special amplitude MμTuTtsM^{TuTts}_{\mu}, where s, t and u are the Mandelstam variables. MμTsTtsM^{TsTts}_{\mu} depends only on the elastic T-matrix evaluated at four sets of (s,t) fixed by the requirement that the amplitude be free of derivatives (\partialT/\partials and /or \partialT/t\partial t). Likewise MμTuTtsM^{TuTts}_{\mu} depends only on the elastic T-matrix evaluated at four sets of (u,t). In deriving these amplitudes, we impose the condition that MμTsTtsM^{TsTts}_{\mu} and MμTuTtsM^{TuTts}_{\mu} reduce to MˉμTsTts\bar{M}^{TsTts}_{\mu} and MˉμTuTts\bar{M}^{TuTts}_{\mu}, respectively, their tree level approximations. The amplitude MˉμTsTts\bar{M}^{TsTts}_{\mu} represents photon emission from a sum of one-particle t-channel exchange diagrams and one-particle s-channel exchange diagrams, while the amplitude MˉμTuTts\bar{M}^{TuTts} _{\mu} represents photon emission from a sum of one-particle t-channel exchange diagrams and one-particle u-channel exchange diagrams. The precise expressions for MˉμTsTts\bar{M}^{TsTts}_{\mu} and MˉμTuTts\bar{M}^{TuTts}_{\mu} are determined by using the radiation decomposition identities of Brodsky and Brown. We point out that it is theoretically impossible to describe all bremsstrahlung processes by using only a single class of soft-photon amplitudes. At least two different classes are required: the amplitudes which depend on s and t or the amplitudes which depend on u and t. When resonance effects are important, the amplitude MμTsTtsM^{TsTts}_{\mu}, not MμLow(st)M^{Low(st)}_{\mu}, should be used. For processes with strong u-channel exchange effects, the amplitude MμTuTtsM^{TuTts}_{\mu} should be the first choice.Comment: 49 pages report # LA-UR-92-270

    Phase II trial of intrapleural paclitaxel injection for non-small-cell lung cancer patients with malignant pleural effusions

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    AbstractA phase II clinical trial of intrapleural paclitaxel injection for malignant effusions of non-small-cell lung cancer (NSCLC) was conducted in order to evaluate the efficacy and toxicity profile of paclitaxel pleurodesis in patients with malignant effusions. From February to May of 1996, 15 NSCLC patients with malignant pleural effusions were enrolled on study. After adequate drainage and assurance of lung re-expansion, paclitaxel 125 mg m−2 diluted in normal saline was infused through a preinserted pig-tail catheter which was removed 2 h later. Chest radiography and sonography were scheduled 4 days later; depending on whether there remained a significant amount of pleural effusion, further drainage by needle thoracentesis or by a pig-tail catheter was performed.All patients were assessable for toxicity. Ipsilateral chest and/or shoulder pain, fever, facial flushing and nausea were the most frequent side-effects. Grade 4 neutropenia, grade 3 anaemia, and grade 3 renal impairment occurred in one patient each. Fourteen patients were evaluable for response at the end of the fourth week. Overall response rate of pleural effusion in evaluable patients was 92·9%, with a complete response rate of 28·6%. There was one out of 14 evaluable patients whose measurable tumour lesion decreased by more than 50% (partial response). No disease progression was noted among evaluable patients at the end of the fourth week. It is concluded that paclitaxel is a useful agent for the treatment of malignant pleural effusions. Because of its relatively low systemic toxicity, intrapleural paclitaxel injection in combination with systemic chemotherapy or radiotherapy can be considered in treating NSCLC patients with malignant pleural effusions

    Subordinates' competency : a potential trigger for workplace ostracism

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    While the competence of subordinates is considered desirable in the workplace, it may create challenges in managing people in organizations. This study examines why subordinates’ competence triggers ostracism within the workplace based on social comparison theory and previous insecurity studies. Data from both managers (N=130) and their subordinates (N=231) provided findings which affirm that, first, some managers regard competent subordinates as potential challengers and thus develop a feeling of insecurity, which creates motivation for the ostracism of those competent subordinates. Second, those subordinates who feel ostracized by managers, may show less commitment towards their managers, feel less confident and engage in negative gossip about their managers. The implications of competence triggered ostracism for management include that competent subordinates require active management and development to avoid potentially damaging relationships between managers and subordinates emerging which would be detrimental to the organization

    Particles at oil–air surfaces : powdered oil, liquid oil marbles, and oil foam

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    The type of material stabilized by four kinds of fluorinated particles (sericite and bentonite platelet clays and spherical zinc oxide) in air–oil mixtures has been investigated. It depends on the particle wettability and the degree of shear. Upon vigorous agitation, oil dispersions are formed in all the oils containing relatively large bentonite particles and in oils of relatively low surface tension (γla < 26 mN m⁻¹) like dodecane, 20 cS silicone, and cyclomethicone containing the other fluorinated particles. Particle-stabilized oil foams were obtained in oils having γla > 26 mN m⁻¹ where the advancing air–oil–solid contact angle θ lies between ca. 90° and 120°. Gentle shaking, however, gives oil-in-air liquid marbles with all the oil–particle systems except for cases where θ is <60°. For oils of tension >24 mN m⁻¹ with omniphobic zinc oxide and sericite particles for which advancing θ ≥ 90°, dry oil powders consisting of oil drops in air which do not leak oil could be made upon gentle agitation up to a critical oil:particle ratio (COPR). Above the COPR, catastrophic phase inversion of the dry oil powders to air-in-oil foams was observed. When sheared on a substrate, the dry oil powders containing at least 60 wt % of oil release the encapsulated oil, making these materials attractive formulations in the cosmetic and food industries

    A theoretical model to elucidate the elusive concept ‘voice' for interpreters

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    This paper is an attempt to elucidate the concept of voice for interpreters in relation to the equally elusive concept pleasant voice for interpreters. The point of departure is that the concept voice for interpreting has to do with the physical properties of a speaker’s voice, which may lead to the effect that a speaker’s voice is heard as pleasant or unpleasant by a listener, depending on how a speaker uses or deploys these physical properties. The paper employs an interdisciplinary approach to reviewing relevant literature and shows that for better interpreter education and interpreting assessment, there is a need to unravel, and unify existing understandings of the concept voice. A new definition is therefore proposed. The new definition consists of a cluster of suprasegmental features resulted from supralaryngeal and laryngeal activities and incorporates in what are traditionally known as fluency features in interpreting. The paper goes on to discuss the potential benefits and implications of the newly proposed definition for both interpreter training and interpreting studies

    Maternal Diet Quality During Pregnancy and Offspring Hepatic Fat in Early Childhood: The Healthy Start Study

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    Background: Overnutrition in utero may increase offspring risk of nonalcoholic fatty liver disease (NAFLD), but the specific contribution of maternal diet quality during pregnancy to this association remains understudied in humans. Objectives: This study aimed to examine the associations of maternal diet quality during pregnancy with offspring hepatic fat in early childhood (median: 5 y old, range: 4–8 y old). Methods: Data were from 278 mother–child pairs in the longitudinal, Colorado-based Healthy Start Study. Multiple 24-h recalls were collected from mothers during pregnancy on a monthly basis (median: 3 recalls, range: 1–8 recalls starting after enrollment), and used to estimate maternal usual nutrient intakes and dietary pattern scores [Healthy Eating Index-2010 (HEI-2010), Dietary Inflammatory Index (DII), and Relative Mediterranean Diet Score (rMED)]. Offspring hepatic fat was measured in early childhood by MRI. Associations of maternal dietary predictors during pregnancy with offspring log-transformed hepatic fat were assessed using linear regression models adjusted for offspring demographics, maternal/perinatal confounders, and maternal total energy intake. Results: Higher maternal fiber intake and rMED scores during pregnancy were associated with lower offspring hepatic fat in early childhood in fully adjusted models [Back-transformed β (95% CI): 0.82 (0.72, 0.94) per 5 g/1000 kcal fiber; 0.93 (0.88, 0.99) per 1 SD for rMED]. In contrast, higher maternal total sugar and added sugar intakes, and DII scores were associated with higher offspring hepatic fat [Back-transformed β (95% CI): 1.18 (1.05, 1.32) per 5% kcal/d added sugar; 1.08 (0.99, 1.18) per 1 SD for DII]. Analyses of dietary pattern subcomponents also revealed that lower maternal intakes of green vegetables and legumes and higher intake of “empty calories” were associated with higher offspring hepatic fat in early childhood. Conclusions: Poorer maternal diet quality during pregnancy was associated with greater offspring susceptibility to hepatic fat in early childhood. Our findings provide insights into potential perinatal targets for the primordial prevention of pediatric NAFLD

    Gemcitabine and cisplatin in a multimodality treatment for locally advanced non-small cell lung cancer

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    The role of new cytotoxic agents like gemcitabine has not yet been proven in the neoadjuvant settings. We designed a phase II study to test the feasibility of using gemcitabine and cisplatin before local treatment for stage III non-small cell lung cancer patients. Patients received three cycles of induction chemotherapy of gemcitabine (1000 mg m−2, days 1, 8, 15) and cisplatin (90 mg m−2, day 15) every 4 weeks before evaluation for operability. Operable patients underwent radical resection. Inoperable patients and patients who had incomplete resection received concurrent chemoradiotherapy with daily low dose cisplatin. All patients who did not progress after local treatment received three more cycles of adjuvant chemotherapy of gemcitabine and cisplatin. Fifty-two patients received induction treatment. Two patients had complete response and 31 patients had partial response (response rate 63.5%) after induction chemotherapy. Thirty-six patients (69%) were operable. Eighteen patients (35%) had their tumours completely resected. Two patients had pathological complete response. Median overall survival was 19.1 months, projected 1-year survival was 66% and 2-year survival was 34%. Three cycles of gemcitabine and cisplatin is effective and can be used as induction treatment before surgery for locally advanced non-small cell lung cancer patients

    Computational Characterization of 3′ Splice Variants in the GFAP Isoform Family

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    Glial fibrillary acidic protein (GFAP) is an intermediate filament (IF) protein specific to central nervous system (CNS) astrocytes. It has been the subject of intense interest due to its association with neurodegenerative diseases, and because of growing evidence that IF proteins not only modulate cellular structure, but also cellular function. Moreover, GFAP has a family of splicing isoforms apparently more complex than that of other CNS IF proteins, consistent with it possessing a range of functional and structural roles. The gene consists of 9 exons, and to date all isoforms associated with 3′ end splicing have been identified from modifications within intron 7, resulting in the generation of exon 7a (GFAPδ/ε) and 7b (GFAPκ). To better understand the nature and functional significance of variation in this region, we used a Bayesian multiple change-point approach to identify conserved regions. This is the first successful application of this method to a single gene – it has previously only been used in whole-genome analyses. We identified several highly or moderately conserved regions throughout the intron 7/7a/7b regions, including untranslated regions and regulatory features, consistent with the biology of GFAP. Several putative unconfirmed features were also identified, including a possible new isoform. We then integrated multiple computational analyses on both the DNA and protein sequences from the mouse, rat and human, showing that the major isoform, GFAPα, has highly conserved structure and features across the three species, whereas the minor isoforms GFAPδ/ε and GFAPκ have low conservation of structure and features at the distal 3′ end, both relative to each other and relative to GFAPα. The overall picture suggests distinct and tightly regulated functions for the 3′ end isoforms, consistent with complex astrocyte biology. The results illustrate a computational approach for characterising splicing isoform families, using both DNA and protein sequences
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