16,146 research outputs found

    Tall sections from non-minimal transformations

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    In previous work, we have shown that elliptic fibrations with two sections, or Mordell-Weil rank one, can always be mapped birationally to a Weierstrass model of a certain form, namely, the Jacobian of a P112\mathbb{P}^{112} model. Most constructions of elliptically fibered Calabi-Yau manifolds with two sections have been carried out assuming that the image of this birational map was a "minimal" Weierstrass model. In this paper, we show that for some elliptically fibered Calabi-Yau manifolds with Mordell-Weil rank-one, the Jacobian of the P112\mathbb{P}^{112} model is not minimal. Said another way, starting from a Calabi-Yau Weierstrass model, the total space must be blown up (thereby destroying the "Calabi-Yau" property) in order to embed the model into P112\mathbb{P}^{112}. In particular, we show that the elliptic fibrations studied recently by Klevers and Taylor fall into this class of models.Comment: 16 page

    Coping With Racism: Moderators of the Discrimination-Adjustment Link Among Mexican-Origin Adolescents

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    What strategies help ethnic minority adolescents to cope with racism? The present study addressed this question by testing the role of ethnic identity, social support, and anger expression and suppression as moderators of the discrimination-adjustment link among 269 Mexican-origin adolescents (Mage = 14.1 years), 12-17 years old from the Midwestern U.S. Results from multilevel moderation analyses indicated that ethnic identity, social support, and anger suppression, respectively, significantly attenuated the relations between discrimination and adjustment problems, whereas outward anger expression exacerbated these relations. Moderation effects differed according to the level of analysis. By identifying effective coping strategies in the discrimination-adjustment link at specific levels of analysis, the present findings can guide future intervention efforts for Latino youth

    Erratum Re: “Coping With Racism: Moderators of the Discrimination—Distress Link Among Mexican-Origin Adolescents”

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    The publisher's final edited version of this article is available at Child Dev This corrects the article "Coping With Racism: Moderators of the Discrimination—Adjustment Link Among Mexican-Origin Adolescents" in Child Dev, volume 89 on page e293

    Cluster, Classify, Regress: A General Method For Learning Discountinous Functions

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    This paper presents a method for solving the supervised learning problem in which the output is highly nonlinear and discontinuous. It is proposed to solve this problem in three stages: (i) cluster the pairs of input-output data points, resulting in a label for each point; (ii) classify the data, where the corresponding label is the output; and finally (iii) perform one separate regression for each class, where the training data corresponds to the subset of the original input-output pairs which have that label according to the classifier. It has not yet been proposed to combine these 3 fundamental building blocks of machine learning in this simple and powerful fashion. This can be viewed as a form of deep learning, where any of the intermediate layers can itself be deep. The utility and robustness of the methodology is illustrated on some toy problems, including one example problem arising from simulation of plasma fusion in a tokamak.Comment: 12 files,6 figure

    Efficacy of turmeric (Curcuma longa) to ameliorate the adverse effects of T-2 toxin in broiler chicks

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    Abstract only availableA 3-wk feeding study was conducted to evaluate the efficacy of turmeric (Curcuma longa) powder (TMP), containing a known level of curcumin to ameliorate the adverse effects of T-2 toxin in broiler chicks. Five pen replicates of 5 chicks each were assigned to each of 6 dietary treatments. Dietary treatments evaluated include: 1) basal diet containing no T-2 toxin or TMP; 2) basal diet supplemented with 0.67% TMP containing 220 mg/kg total curcuminoids (TCMN); 3) basal diet supplemented with 1 mg/kg T-2; 4) basal diet supplemented with 1 mg/kg T-2 and 220 mg/kg TCMN; 5) basal diet supplemented with 2 mg/kg T-2; 6) and basal diet supplemented with 2 mg/kg T-2 and 220 mg/kg TCMN. The addition of T-2 toxin or TCMN to the diet had no effect (P > 0.05) on feed intake, body weight gain, or feed conversion which averaged 870g, 685g, and 1.29 g:g, respectively, across all treatments. Similarly, there was no effect (P > 0.05) of T-2 or TCMN on relative liver weight which averaged 3.07g across all treatments. Results indicate that 2 mg/kg T-2 was not toxic to broiler chicks fed dietary treatments for 3 weeks. Results also indicate that the addition of 220 mg/kg TCMN to the basal diet was not beneficial to chicks. It remains to be seen if T-2 toxin negatively affected the antioxidant status and hepatic gene expression of chicks, and if TCMN was beneficial in ameliorating any observed negative effects. Samples are currently being analyzed for antioxidant activity and changes in gene expression.Gyeongsang National Universit

    The Administered-Price Hypothesis Revisited

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    The relationship between market structure and firms’ pricing behaviour has been a major and controversial issue in industrial economics. The question of how firms’ pricing behaviour differs across market structures is the focus of the administered-price thesis. In this paper the authors review theories providing rationales for the administered-price thesis and their empirical underpinnings, and methodological controversies concerning price series of differnt industries

    Self-Assembly of Coil/Liquid-Crystalline Diblock Copolymers in a Liquid Crystal Solvent

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    Diblock copolymers having a random-coil polymer block (polystyrene, PS) connected to a side-group liquid crystal polymer (SGLCP) self-assemble in a nematic liquid crystal (LC), 4-pentyl-4′-cyanobiphenyl, into micelles with PS-rich cores and SGLCP-rich coronas. The morphologies of block copolymers with varying PS content are characterized as a function of temperature and concentration using small-angle neutron scattering, rheometry, and transmission electron microscopy. Unlike conventional solvents, the nematic LC can undergo a first-order transition between distinct fluid phases, accessing the regimes of both strong and slight selectivity in a single polymer/solvent pair. Micelles dissolve away above a microphase separation temperature (MST) that is often equal to the solution’s isotropization point, TNI. However, increasing or decreasing the polymer’s PS content can shift the MST to be above or below TNI, respectively, and in the former case, micelles abruptly swell with solvent at TNI. Comparable effects can be achieved by modulating the overall polymer concentration

    Microscopic colitis: A review of etiology, treatment and refractory disease

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    Microscopic colitis is a common cause of chronic, nonbloody diarrhea. Microscopic colitis is more common in women than men and usually affects patients in their sixth and seventh decade. This article reviews the etiology and medical management of microscopic colitis. The etiology of microscopic colitis is unknown, but it is associated with autoimmune disorders, such as celiac disease, polyarthritis, and thyroid disorders. Smoking has been identified as a risk factor of microscopic colitis. Exposure to medications, such as non-steroidal anti-inflammatory drugs, proton pump inhibitors, and selective serotonin reuptake inhibitors, is suspected to play a role in microscopic colitis, although their direct causal relationship has not been proven. Multiple medications, including corticosteroids, anti-diarrheals, cholestyramine, bismuth, 5-aminosalicylates, and immunomodulators, have been used to treat microscopic colitis with variable response rates. Budesonide is effective in inducing and maintaining clinical remission but relapse rate is as high as 82% when budesonide is discontinued. There is limited data on management of steroid-dependent microscopic colitis or refractory microscopic colitis. Immunomodulators seem to have low response rate 0%-56% for patients with refractory microscopic colitis. Response rate 66%-100% was observed for use of anti-tumor necrosis factor (TNF) therapy for refractory microscopic colitis. Anti-TNF and diverting ileostomy may be an option in severe or refractory microscopic colitis
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