A
bstract
We study two-dimensional
N
=
2
,
2
supersymmetric gauged linear sigma models (GLSM) on the Ω-deformed sphere,
S
Ω
2
, which is a one-parameter deformation of the
A
-twisted sphere. We ...provide an exact formula for the
S
Ω
2
supersymmetric correlation functions using supersymmetric localization. The contribution of each instanton sector is given in terms of a Jeffrey-Kirwan residue on the Coulomb branch. In the limit of vanishing Ω-deformation, the localization formula greatly simplifies the computation of
A
-twisted correlation functions, and leads to new results for non-abelian theories. We discuss a number of examples and comment on the
ϵ
Ω
-deformation of the quantum cohomology relations. Finally, we present a complementary Higgs branch localization scheme in the special case of abelian gauge groups.
A
bstract
Six-dimensional supergravity theories with
= (1, 0) supersymmetry must satisfy anomaly equations. These equations come from demanding the cancellation of gravitational, gauge and mixed ...anomalies. The anomaly equations have implications for the geometrical data of Calabi-Yau threefolds, since F-theory compactified on an elliptically fibered Calabi-Yau threefold with a section generates a consistent six-dimensional
= (1, 0) supergravity theory. In this paper, we show that the anomaly equations can be summarized by three intersection theory identities. In the process we also identify the geometric counterpart of the anomaly coefficients — in particular, those of the abelian gauge groups — that govern the low-energy dynamics of the theory. We discuss the results in the context of investigating string universality in six dimensions.
A
bstract
The Mordell-Weil group of an elliptically fibered Calabi-Yau threefold
X
contains information about the abelian sector of the six-dimensional theory obtained by compactifying F-theory on
X
.... After examining features of the abelian anomaly coefficient matrix and U(1) charge quantization conditions of general F-theory vacua, we study CalabiYau threefolds with Mordell-Weil rank-one as a first step towards understanding the features of the Mordell-Weil group of threefolds in more detail. In particular, we generate an interesting class of F-theory models with U(1) gauge symmetry that have matter with both charges 1 and 2. The anomaly equations — which relate the Néron-Tate height of a section to intersection numbers between the section and fibral rational curves of the manifold — serve as an important tool in our analysis.
Summary Background Outcomes are poor for patients with previously treated, advanced or metastatic non-small-cell lung cancer (NSCLC). The anti-programmed death ligand 1 (PD-L1) antibody atezolizumab ...is clinically active against cancer, including NSCLC, especially cancers expressing PD-L1 on tumour cells, tumour-infiltrating immune cells, or both. We assessed efficacy and safety of atezolizumab versus docetaxel in previously treated NSCLC, analysed by PD-L1 expression levels on tumour cells and tumour-infiltrating immune cells and in the intention-to-treat population. Methods In this open-label, phase 2 randomised controlled trial, patients with NSCLC who progressed on post-platinum chemotherapy were recruited in 61 academic medical centres and community oncology practices across 13 countries in Europe and North America. Key inclusion criteria were Eastern Cooperative Oncology Group performance status 0 or 1, measurable disease by Response Evaluation Criteria In Solid Tumors version 1.1 (RECIST v1.1), and adequate haematological and end-organ function. Patients were stratified by PD-L1 tumour-infiltrating immune cell status, histology, and previous lines of therapy, and randomly assigned (1:1) by permuted block randomisation (with a block size of four) using an interactive voice or web system to receive intravenous atezolizumab 1200 mg or docetaxel 75 mg/m2 once every 3 weeks. Baseline PD-L1 expression was scored by immunohistochemistry in tumour cells (as percentage of PD-L1-expressing tumour cells TC3≥50%, TC2≥5% and <50%, TC1≥1% and <5%, and TC0<1%) and tumour-infiltrating immune cells (as percentage of tumour area: IC3≥10%, IC2≥5% and <10%, IC1≥1% and <5%, and IC0<1%). The primary endpoint was overall survival in the intention-to-treat population and PD-L1 subgroups at 173 deaths. Biomarkers were assessed in an exploratory analysis. We assessed safety in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov , number NCT01903993. Findings Patients were enrolled between Aug 5, 2013, and March 31, 2014. 144 patients were randomly allocated to the atezolizumab group, and 143 to the docetaxel group. 142 patients received at least one dose of atezolizumab and 135 received docetaxel. Overall survival in the intention-to-treat population was 12·6 months (95% CI 9·7–16·4) for atezolizumab versus 9·7 months (8·6–12·0) for docetaxel (hazard ratio HR 0·73 95% CI 0·53–0·99; p=0·04). Increasing improvement in overall survival was associated with increasing PD-L1 expression (TC3 or IC3 HR 0·49 0·22–1·07; p=0·068, TC2/3 or IC2/3 HR 0·54 0·33–0·89; p=0·014, TC1/2/3 or IC1/2/3 HR 0·59 0·40–0·85; p=0·005, TC0 and IC0 HR 1·04 0·62–1·75; p=0·871). In our exploratory analysis, patients with pre-existing immunity, defined by high T-effector–interferon-γ-associated gene expression, had improved overall survival with atezolizumab. 11 (8%) patients in the atezolizumab group discontinued because of adverse events versus 30 (22%) patients in the docetaxel group. 16 (11%) patients in the atezolizumab group versus 52 (39%) patients in the docetaxel group had treatment-related grade 3–4 adverse events, and one (<1%) patient in the atezolizumab group versus three (2%) patients in the docetaxel group died from a treatment-related adverse event. Interpretation Atezolizumab significantly improved survival compared with docetaxel in patients with previously treated NSCLC. Improvement correlated with PD-L1 immunohistochemistry expression on tumour cells and tumour-infiltrating immune cells, suggesting that PD-L1 expression is predictive for atezolizumab benefit. Atezolizumab was well tolerated, with a safety profile distinct from chemotherapy. Funding F Hoffmann-La Roche/Genentech Inc.
Topological matter is known to exhibit unconventional surface states and anomalous transport owing to unusual bulk electronic topology. In this study, we use photoemission spectroscopy and quantum ...transport to elucidate the topology of the room temperature magnet Co
MnGa. We observe sharp bulk Weyl fermion line dispersions indicative of nontrivial topological invariants present in the magnetic phase. On the surface of the magnet, we observe electronic wave functions that take the form of drumheads, enabling us to directly visualize the crucial components of the bulk-boundary topological correspondence. By considering the Berry curvature field associated with the observed topological Weyl fermion lines, we quantitatively account for the giant anomalous Hall response observed in this magnet. Our experimental results suggest a rich interplay of strongly interacting electrons and topology in quantum matter.
Within the ivory tower of academia, the coronavirus disease 2019 (COVID-19) pandemic stands to disproportionately impact the invisible workforce of postdoctoral researchers (postdocs). Faced with ...university closures, hiring freezes, and a general lack of support and benefits, an entire generation of postdocs and their knowledge and skills may be lost to academia without intervention.
Ecological niche models are widely used in ecology and biogeography. Maxent is one of the most frequently used niche modeling tools, and many studies have aimed to optimize its performance. However, ...scholars have conflicting views on the treatment of predictor collinearity in Maxent modeling. Despite this lack of consensus, quantitative examinations of the effects of collinearity on Maxent modeling, especially in model transfer scenarios, are lacking. To address this knowledge gap, here we quantify the effects of collinearity under different scenarios of Maxent model training and projection. We separately examine the effects of predictor collinearity, collinearity shifts between training and testing data, and environmental novelty on model performance. We demonstrate that excluding highly correlated predictor variables does not significantly influence model performance. However, we find that collinearity shift and environmental novelty have significant negative effects on the performance of model transfer. We thus conclude that (a) Maxent is robust to predictor collinearity in model training; (b) the strategy of excluding highly correlated variables has little impact because Maxent accounts for redundant variables; and (c) collinearity shift and environmental novelty can negatively affect Maxent model transferability. We therefore recommend to quantify and report collinearity shift and environmental novelty to better infer model accuracy when models are spatially and/or temporally transferred.
Excluding highly correlated variables does not affect Maxent model performance. Model transfer may lead to novel environment and collinearity shift, while both can negatively affect model performance.
•Adsorption of Cs+ onto expanding clay minerals change the structure.•Cs+ is migrated into deeper interlayer from frayed edge sites and fixed.•The collapse of the frayed edge site and interlayer by ...Cs+ are the mechanism of irreversible fixation.
In this study, we reviewed the selective adsorption and irreversible fixation of cesium (Cs+) on clay minerals. The selective adsorption of Cs+ results from reactions with frayed edge sites (FES) of clay minerals. The content of FES is about 0.1–2.0% of the total cation exchange capacity (CEC). The fractionation of Cs+ in actual accident sites mainly exists as a residue, which is important because it is closely related to the strong binding between Cs+ and soils. Cs+ adsorbed onto FES can move into the deeper interlayer via weathering processes, thereby Cs+ can be irreversibly fixed in the interlayer of non-expanding 2:1 layered clay mineral. Additionally, Cs+ can be adsorbed in the interlayer of the expanding clay mineral and can be fixed by interlayer collapse. For this reason, Cs+ adsorption onto FES is defined as ‘selective adsorption’ subsequent sorption in the interlayer as ‘irreversible fixation’. Furthermore, the extended X-ray absorption fine structure (EXAFS) analysis can confirm that Cs+ bound to illite is coordinated with the outer surface (OOS) and interlayer surface oxygens (OIS) through FES or interlayer sites. Through these processes, Cs+ is adsorbed selectively onto FES, while Cs+ can subsequently move into the interlayer and become more strongly fixed.
Although studies have identified hundreds of loci associated with human traits and diseases, pinpointing causal alleles remains difficult, particularly for non-coding variants. To address this ...challenge, we adapted the massively parallel reporter assay (MPRA) to identify variants that directly modulate gene expression. We applied it to 32,373 variants from 3,642 cis-expression quantitative trait loci and control regions. Detection by MPRA was strongly correlated with measures of regulatory function. We demonstrate MPRA’s capabilities for pinpointing causal alleles, using it to identify 842 variants showing differential expression between alleles, including 53 well-annotated variants associated with diseases and traits. We investigated one in detail, a risk allele for ankylosing spondylitis, and provide direct evidence of a non-coding variant that alters expression of the prostaglandin EP4 receptor. These results create a resource of concrete leads and illustrate the promise of this approach for comprehensively interrogating how non-coding polymorphism shapes human biology.
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•A new version of MPRA with greater throughput and sensitivity•Evaluation of 32,373 variants associated with eQTLs in lymphoblastoid cell lines•842 variants showed differential gene expression between alleles•Use of CRISPR/cas9 to identify a distal eQTL causal allele for PTGER4
A massively parallel reporter assay analyzes thousands of human polymorphisms to identify alleles that impact gene expression, providing a tool with which to move from disease-associated GWAS hits to the identification of functional variants.
The Rayleigh–Taylor (RT) instability occurs at an interface between two fluids of differing density during an acceleration. These instabilities can occur in very diverse settings, from inertial ...confinement fusion (ICF) implosions over spatial scales of ~10−3−10−1 cm (10–1,000 μm) to supernova explosions at spatial scales of ~1012 cm and larger. We describe experiments and techniques for reducing (“stabilizing”) RT growth in high-energy density (HED) settings on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. Three unique regimes of stabilization are described: (i) at an ablation front, (ii) behind a radiative shock, and (iii) due to material strength. For comparison, we also show results from nonstabilized “classical” RT instability evolution in HED regimes on the NIF. Examples from experiments on the NIF in each regime are given. These phenomena also occur in several astrophysical scenarios and planetary science Drake R (2005) Plasma Phys Controlled Fusion 47:B419–B440; Dahl TW, Stevenson DJ (2010) Earth Planet Sci Lett 295:177–186.
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