136 research outputs found
Topological Strings and (Almost) Modular Forms
The B-model topological string theory on a Calabi-Yau threefold X has a
symmetry group Gamma, generated by monodromies of the periods of X. This acts
on the topological string wave function in a natural way, governed by the
quantum mechanics of the phase space H^3(X). We show that, depending on the
choice of polarization, the genus g topological string amplitude is either a
holomorphic quasi-modular form or an almost holomorphic modular form of weight
0 under Gamma. Moreover, at each genus, certain combinations of genus g
amplitudes are both modular and holomorphic. We illustrate this for the local
Calabi-Yau manifolds giving rise to Seiberg-Witten gauge theories in four
dimensions and local P_2 and P_1 x P_1. As a byproduct, we also obtain a simple
way of relating the topological string amplitudes near different points in the
moduli space, which we use to give predictions for Gromov-Witten invariants of
the orbifold C^3/Z_3.Comment: 62 pages, 1 figure; v2: minor correction
Direct Integration of the Topological String
We present a new method to solve the holomorphic anomaly equations governing
the free energies of type B topological strings. The method is based on direct
integration with respect to the non-holomorphic dependence of the amplitudes,
and relies on the interplay between non-holomorphicity and modularity
properties of the topological string amplitudes. We develop a formalism valid
for any Calabi-Yau manifold and we study in detail two examples, providing
closed expressions for the amplitudes at low genus, as well as a discussion of
the boundary conditions that fix the holomorphic ambiguity. The first example
is the non-compact Calabi-Yau underlying Seiberg-Witten theory and its
gravitational corrections. The second example is the Enriques Calabi-Yau, which
we solve in full generality up to genus six. We discuss various aspects of this
model: we obtain a new method to generate holomorphic automorphic forms on the
Enriques moduli space, we write down a new product formula for the fiber
amplitudes at all genus, and we analyze in detail the field theory limit. This
allows us to uncover the modularity properties of SU(2), N=2 super Yang-Mills
theory with four massless hypermultiplets.Comment: 75 pages, 3 figure
Metastasis to the breast from an adenocarcinoma of the lung with extensive micropapillary component: a case report and review of the literature
Breast metastasis from extra-mammary malignancy is rare. Based on the literature an incidence of 0.4-1.3% is reported. The primary malignancies most commonly metastasizing to the breast are leukemia-lymphoma, and malignant melanoma. We present a case of metastasis to the breast from a pulmonary adenocarcinoma, with extensive micropapillary component, diagnosed concomitantly with the primary tumor. A 73-year-old female presented with dyspnea and dry cough of 4 weeks duration and a massive pleural effusion was found on a chest radiograph. Additionally, on physical examination a poorly defined mass was noted in the upper outer quadrant of the left breast. The patient underwent bronchoscopy, excisional breast biopsy and medical thoracoscopy. By cytology, histology and immunohistochemistry primary lung adenocarcinoma with metastasis to the breast and parietal pleura was diagnosed. Both the primary and metastatic anatomic sites demonstrated histologically extensive micropapillary component, which is recently recognized as an important prognostic factor. The patient received chemotherapy but passed away within 7 months. Accurate differentiation of metastatic from primary carcinoma is of crucial importance because the treatment and prognosis differ significantly
Engineering the Redox Potential over a Wide Range within a New Class of FeS Proteins
Abstract: MitoNEET is a newly discovered mitochondrial protein and a target of the TZD class of antidiabetes drugs. MitoNEET is homodimeric with each protomer binding a [2Fe-2S] center through a rare 3-Cys and 1-His coordination geometry. Both the fold and the coordination of the [2Fe-2S] centers suggest that it could have novel properties compared to other known [2Fe-2S] proteins. We tested the robustness of mitoNEET to mutation and the range over which the redox potential (EM) could be tuned. We found that the protein could tolerate an array of mutations that modified the EM of the [2Fe-2S] center over a range of ∼700 mV, which is the largest EM range engineered in an FeS protein and, importantly, spans the cellular redox range (+200 to-300 mV). These properties make mitoNEET potentially useful for both physiological studies and industrial applications as a stable, water-soluble, redox agent
Equidistribution for higher-rank Abelian actions on Heisenberg nilmanifolds
2010 Mathematics Subject Classification: Primary: 37C85, 37A17, 37A45; Secondary: 11K36, 11L07.We prove quantitative equidistribution results for actions of Abelian subgroups of the (2g + 1)-dimensional Heisenberg group acting on compact (2g + 1)-dimensional homogeneous nilmanifolds. The results are based on the study of the C∞-cohomology of the action of such groups, on tame estimates of the associated cohomological equations and on a renormalization method initially applied by Forni to surface flows and by Forni and the second author to other parabolic flows. As an application we obtain bounds for finite Theta sums defined by real quadratic forms in g variables, generalizing the classical results of Hardy and Littlewood [25, 26] and the optimal result of Fiedler, Jurkat, and Körner [17] to higher dimension.This work was partially done while L. Flaminio visited the Isaac Newton Institute in Cambridge, UK. He wishes to thank the Institute and the organizers of the program Interactions between Dynamics of Group Actions and Number Theory for their hospitality. L. Flaminio was supported in part by the Labex CEMPI (ANR-11-LABX-07). S. Cosentino was partially supported by CMAT - Centro de Matematica da Universidade do Minho, financed by the Strategic Project PEst-OE/MAT/UI0013/2014
Exposure-in-vivo containing interventions to improve work functioning of workers with anxiety disorder: a systematic review
<p>Abstract</p> <p>Background</p> <p>Anxiety disorders are associated with functional disability, sickness absence, and decreased productivity. Effective treatments of anxiety disorders can result in remission of symptoms. However the effects on work related outcomes are largely unknown. Exposure in vivo is potentially well fit to improve work-related outcomes. This study systematically reviews the effectiveness of exposure-in-vivo containing interventions in reducing work-related adverse outcomes in workers with anxiety disorders.</p> <p>Methods</p> <p>A systematic study search was conducted in Medline, Cinahl, Embase and Psycinfo. Two reviewers independently extracted data and from each study assessed the quality of evidence by using the GRADE approach. We performed a meta-analysis if data showed sufficient clinical homogeneity.</p> <p>Results</p> <p>Seven studies containing 11 exposure-in-vivo interventions were included. Four studies were focused on Obsessive Compulsive Disorder (OCD), two on Post Traumatic Stress Disorder (PTSD), and one on a mixed group of OCD and severe phobias. The studies were grouped according to type of anxiety disorder and subsequently according to type of comparisons. For OCD, exposure-in-vivo containing interventions can yield better work-related outcomes compared to medication (SSRIs) and relaxation but not better compared to response prevention. The results on anxiety outcomes were similar. The net contribution of exposure in vivo in two OCD intervention programs is also presented as a meta-analysis and shows significant positive results on work role limitations. The calculated pooled effect size with 95% confidence interval was 0.72 (0.28, 1.15). For PTSD, exposure-in-vivo containing interventions can yield better work-related and anxiety-related outcomes compared to a waiting-list but not better compared to imaginal exposure.</p> <p>Conclusions</p> <p>Exposure in vivo as part of an anxiety treatment can reduce work-related adverse outcomes in workers with OCD and PTSD better than various other anxiety treatments or a waiting-list. We recommend that it should be studied how the results of these studies can be transferred to the practice of occupational health professionals and how clinicians can make better use of them to improve work-related outcomes. In future research, priority should be given to high-quality randomised controlled trials (RCTs) in which exposure-in-vivo containing interventions are applied to a variety of anxiety disorders and compared with other clinical anxiety treatments such as SSRIs. Work-related outcomes, in particular work functioning and sickness absence, need to be assessed with reliable and valid measures.</p
Empirical Research on Sovereign Debt and Default
The long history of sovereign debt and the associated enforcement problem have attracted researchers in many fields. In this paper, we survey empirical work by economists, historians, and political scientists. As we review the empirical literature, we emphasize parallel developments in the theory of sovereign debt. One major theme emerges. Although recent research has sought to balance theoretical and empirical considerations, there remains a gap between theories of sovereign debt and the data used to test them. We recommend a number of steps that researchers can take to improve the correspondence between theory and data
Catalytic Cycle of Multicopper Oxidases Studied by Combined Quantum- and Molecular-Mechanical Free-Energy Perturbation Methods
We have used combined quantum mechanical and molecular mechanical free-energy perturbation
methods in combination with explicit solvent simulations to study the reaction mechanism of the
multicopper oxidases, in particular the regeneration of the reduced state from the native
intermediate. For 52 putative states of the trinuclear copper cluster, differing in the oxidation states
of the copper ions and the protonation states of water- and O2-derived ligands, we have studied
redox potentials, acidity constants, isomerisation reactions, as well as water- and O2 binding
reactions. Thereby, we can propose a full reaction mechanism of the multicopper oxidases with
atomic detail. We also show that the two copper sites in the protein communicate so that redox
potentials and acidity constants of one site are affected by up to 0.2 V or 3 pKa units by a change
in the oxidation state of the other site
- …