2,059 research outputs found

    Interacting Strings in Matrix String Theory

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    It is here explained how the Green-Schwarz superstring theory arises from Matrix String Theory. This is obtained as the strong YM-coupling limit of the theory expanded around its BPS instantonic configurations, via the identification of the interacting string diagram with the spectral curve of the relevant configuration. Both the GS action and the perturbative weight gsχg_s^{-\chi}, where χ\chi is the Euler characteristic of the world-sheet surface and gsg_s the string coupling, are obtained.Comment: 11 pages, no figures, two references adde

    N=2 SYM RG Scale as Modulus for WDVV Equations

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    We derive a new set of WDVV equations for N=2 SYM in which the renormalization scale Λ\Lambda is identified with the distinguished modulus which naturally arises in topological field theories.Comment: 6 pages, LaTe

    Imaging memory in temporal lobe epilepsy: predicting the effects of temporal lobe resection

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    Functional magnetic resonance imaging can demonstrate the functional anatomy of cognitive processes. In patients with refractory temporal lobe epilepsy, evaluation of preoperative verbal and visual memory function is important as anterior temporal lobe resections may result in material specific memory impairment, typically verbal memory decline following left and visual memory decline after right anterior temporal lobe resection. This study aimed to investigate reorganization of memory functions in temporal lobe epilepsy and to determine whether preoperative memory functional magnetic resonance imaging may predict memory changes following anterior temporal lobe resection. We studied 72 patients with unilateral medial temporal lobe epilepsy (41 left) and 20 healthy controls. A functional magnetic resonance imaging memory encoding paradigm for pictures, words and faces was used testing verbal and visual memory in a single scanning session on a 3T magnetic resonance imaging scanner. Fifty-four patients subsequently underwent left (29) or right (25) anterior temporal lobe resection. Verbal and design learning were assessed before and 4 months after surgery. Event-related functional magnetic resonance imaging analysis revealed that in left temporal lobe epilepsy, greater left hippocampal activation for word encoding correlated with better verbal memory. In right temporal lobe epilepsy, greater right hippocampal activation for face encoding correlated with better visual memory. In left temporal lobe epilepsy, greater left than right anterior hippocampal activation on word encoding correlated with greater verbal memory decline after left anterior temporal lobe resection, while greater left than right posterior hippocampal activation correlated with better postoperative verbal memory outcome. In right temporal lobe epilepsy, greater right than left anterior hippocampal functional magnetic resonance imaging activation on face encoding predicted greater visual memory decline after right anterior temporal lobe resection, while greater right than left posterior hippocampal activation correlated with better visual memory outcome. Stepwise linear regression identified asymmetry of activation for encoding words and faces in the ipsilateral anterior medial temporal lobe as strongest predictors for postoperative verbal and visual memory decline. Activation asymmetry, language lateralization and performance on preoperative neuropsychological tests predicted clinically significant verbal memory decline in all patients who underwent left anterior temporal lobe resection, but were less able to predict visual memory decline after right anterior temporal lobe resection. Preoperative memory functional magnetic resonance imaging was the strongest predictor of verbal and visual memory decline following anterior temporal lobe resection. Preoperatively, verbal and visual memory function utilized the damaged, ipsilateral hippocampus and also the contralateral hippocampus. Memory function in the ipsilateral posterior hippocampus may contribute to better preservation of memory after surgery

    Matone's relation of N=2 super Yang-Mills and spectrum of Toda chain

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    In N=2 super Yang-Mills theory, the Matone's relation relates instanton corrections of the prepotential to instanton corrections of scalar field condensation . This relation has been proved to hold for Omega deformed theories too, using localization method. In this paper, we first give a case study supporting the relation, which does not rely on the localization technique. Especially, we show that the magnetic expansion also satisfies a relation of Matone's type. Then we discuss implication of the relation for the spectrum of periodic Toda chain, in the context of recently proposed Nekrasov-Shatashvili scheme.Comment: 17 pages; v2 minor changes, references added; v3 more material added in 2nd section, clarification in 4th sectio

    Taming open/closed string duality with a Losev trick

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    A target space string field theory formulation for open and closed B-model is provided by giving a Batalin-Vilkovisky quantization of the holomorphic Chern-Simons theory with off-shell gravity background. The target space expression for the coefficients of the holomorphic anomaly equation for open strings are obtained. Furthermore, open/closed string duality is proved from a judicious integration over the open string fields. In particular, by restriction to the case of independence on continuous open moduli, the shift formulas of [7] are reproduced and shown therefore to encode the data of a closed string dual.Comment: 22 pages, no figures; v.2 Refs. and a comment added

    Multiple effects of CDK4/6 inhibition in cancer: From cell cycle arrest to immunomodulation

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    Dysregulation of the cell cycle is a hallmark of cancer that leads to aberrant cellular proliferation. CDK4/6 are cyclin-dependent kinases activated in response to proliferative signaling, which induce RB hyper-phosphorylation and hence activation of E2F transcription factors, thus promoting cell cycle progression through the S phase. Pharmacologic inhibition of CDK4/6 by palbociclib, ribociclib, or abemaciclib has been showing promising activity in multiple cancers with the best results achieved in combination with other agents. Indeed, CDK4/6 inhibitors are currently approved in combination with endocrine therapy for the treatment of estrogen receptor-positive, human epidermal growth factor receptor 2-negative advanced or metastatic breast cancer. Moreover, a number of clinical trials are currently underway to test the efficacy of combining CDK4/6 inhibitors with different drugs not only in breast but also in other types of cancer. Beyond the inhibition of cell proliferation, CDK4/6 inhibitors have recently revealed new effects on cancer cells and on tumor microenvironment. In particular, it has been reported that these agents induce a senescent-like phenotype, impact on cell metabolism and exert both immunomodulatory and immunogenic effects. Here we describe recent data on the anti-tumor effects of CDK4/6 inhibitors as single agents or in combined therapies, focusing in particular on their metabolic and immunomodulatory activities

    Instantons on ALE spaces and Super Liouville Conformal Field Theories

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    We provide evidence that the conformal blocks of N=1 super Liouville conformal field theory are described in terms of the SU(2) Nekrasov partition function on the ALE space O_{P^1}(-2).Comment: 10 page

    Probing gas adsorption in zeolites by variable-temperature IR spectroscopy: An overview of current research

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    The current state of the art in the application of variable-temperature IR (VTIR) spectroscopy to the study of (i) adsorption sites in zeolites, including dual cation sites; (ii) the structure of adsorption complexes and (iii) gas-solid interaction energy is reviewed. The main focus is placed on the potential use of zeolites for gas separation, purification and transport, but possible extension to the field of heterogeneous catalysis is also envisaged. A critical comparison with classical IR spectroscopy and adsorption calorimetry shows that the main merits of VTIR spectroscopy are (i) its ability to provide simultaneously the spectroscopic signature of the adsorption complex and the standard enthalpy change involved in the adsorption process; and (ii) the enhanced potential of VTIR to be site specific in favorable cases

    Nonperturbative Relations in N=2 SUSY Yang-Mills and WDVV equation

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    We find the nonperturbative relation between trϕ2\langle {\rm tr} \phi^2 \rangle, trϕ3\langle {\rm tr} \phi^3\rangle the prepotential F{\cal F} and the vevs ϕi\langle \phi_i\rangle in N=2N=2 supersymmetric Yang-Mills theories with gauge group SU(3)SU(3). Nonlinear differential equations for F{\cal F} including the Witten -- Dijkgraaf -- Verlinde -- Verlinde equation are obtained. This indicates that N=2N=2 SYM theories are essentially topological field theories and that should be seen as low-energy limit of some topological string theory. Furthermore, we construct relevant modular invariant quantities, derive canonical relations between the periods and investigate the structure of the beta function by giving its explicit form in the moduli coordinates. In doing this we discuss the uniformization problem for the quantum moduli space. The method we propose can be generalized to N=2N=2 supersymmetric Yang-Mills theories with higher rank gauge groups.Comment: 12 pages, LaTex. Expanded version. New results, corrections, references and acknowledgements adde

    Seasonal effect on the technological and chemical traits of sheep "ricotta Pistoiese" cheese

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    The "ricotta di pecora pistoiese" is comprised in the list of the traditional agrofood products of Tuscany and the relative PDO (Protected Designation of Origin) has be required. This research, analysing the making process, aimed to evaluate its chemical and nutritive traits as influenced by some factors, with particular attention to the season. During the four seasons of two consecutive years, the making process of ricotta cheese was monitored in four farms for a total of 32 control-days. Yields, chemical composition and fatty acid profile of fat were determined. The amount of milk added to whey influenced the fat and protein content and the yields at 0 and 24 hours. Season affected only the protein content, higher in winter and spring. Fatty acid composition was influenced strongly by the season being the ricotta cheese of summer richer of monounsaturated and polyunsaturated FA than that of autumn and winter, probably due to the feeding regimen based mainly on fresh grass
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