3,681 research outputs found
Stabilizing All Geometric Moduli in Heterotic Calabi-Yau Vacua
We propose a scenario to stabilize all geometric moduli - that is, the
complex structure, Kahler moduli and the dilaton - in smooth heterotic
Calabi-Yau compactifications without Neveu-Schwarz three-form flux. This is
accomplished using the gauge bundle required in any heterotic compactification,
whose perturbative effects on the moduli are combined with non-perturbative
corrections. We argue that, for appropriate gauge bundles, all complex
structure and a large number of other moduli can be perturbatively stabilized -
in the most restrictive case, leaving only one combination of Kahler moduli and
the dilaton as a flat direction. At this stage, the remaining moduli space
consists of Minkowski vacua. That is, the perturbative superpotential vanishes
in the vacuum without the necessity to fine-tune flux. Finally, we incorporate
non-perturbative effects such as gaugino condensation and/or instantons. These
are strongly constrained by the anomalous U(1) symmetries which arise from the
required bundle constructions. We present a specific example, with a consistent
choice of non-perturbative effects, where all remaining flat directions are
stabilized in an AdS vacuum.Comment: 24 pages, 2 figure
The essential value of long-term experimental data for hydrology and water management
We would like to thank the European Research Council ERC for funding the VeWa project and most of Tetzlaff's time (project GA 335910 VeWa). No data were used in producing this manuscript.Peer reviewedPublisher PD
The electron accelerator for the AWAKE experiment at CERN
The AWAKE collaboration prepares a proton driven plasma wakefield acceleration experiment using the SPS beam at CERN. A long proton bunch extracted from the SPS interacts with a high power laser and a 10 m long rubidium vapour plasma cell to create strong wakefields allowing sustained electron acceleration. The electron bunch to probe these wakefields is supplied by a 20 MeV electron accelerator. The electron accelerator consists of an RF-gun and a short booster structure. This electron source should provide beams with intensities between 0.1 and 1 nC, bunch lengths between 0.3 and 3 ps and an emittance of the order of 2 mm mrad. The wide range of parameters should cope with the uncertainties and future prospects of the planned experiments. The layout of the electron accelerator, its instrumentation and beam dynamics simulations are presented
Validating decentralised frequency control regimes : a distributed hardware in the loop approach
Interface electronic states and boundary conditions for envelope functions
The envelope-function method with generalized boundary conditions is applied
to the description of localized and resonant interface states. A complete set
of phenomenological conditions which restrict the form of connection rules for
envelope functions is derived using the Hermiticity and symmetry requirements.
Empirical coefficients in the connection rules play role of material parameters
which characterize an internal structure of every particular heterointerface.
As an illustration we present the derivation of the most general connection
rules for the one-band effective mass and 4-band Kane models. The conditions
for the existence of Tamm-like localized interface states are established. It
is shown that a nontrivial form of the connection rules can also result in the
formation of resonant states. The most transparent manifestation of such states
is the resonant tunneling through a single-barrier heterostructure.Comment: RevTeX4, 11 pages, 5 eps figures, submitted to Phys.Rev.
Stabilizing the Complex Structure in Heterotic Calabi-Yau Vacua
In this paper, we show that the presence of gauge fields in heterotic
Calabi-Yau compacitifications causes the stabilisation of some, or all, of the
complex structure moduli of the Calabi-Yau manifold while maintaining a
Minkowski vacuum. Certain deformations of the Calabi-Yau complex structure,
with all other moduli held fixed, can lead to the gauge bundle becoming
non-holomorphic and, hence, non-supersymmetric. This leads to an F-term
potential which stabilizes the corresponding complex structure moduli. We use
10- and 4-dimensional field theory arguments as well as a derivation based
purely on algebraic geometry to show that this picture is indeed correct. An
explicit example is presented in which a large subset of complex structure
moduli is fixed. We demonstrate that this type of theory can serve as the
hidden sector in heterotic vacua and can co-exist with realistic particle
physics.Comment: 17 pages, Late
Sequencing of sporadic Attention‐Deficit Hyperactivity Disorder (ADHD) identifies novel and potentially pathogenic de novo variants and excludes overlap with genes associated with autism spectrum disorder
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137575/1/ajmgb32527.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137575/2/ajmgb32527_am.pd
The chicken talpid3 gene encodes a novel protein that is essential for hedgehog signaling
Talpid(3) is a classical chicken mutant with abnormal limb patterning and malformations in other regions of the embryo known to depend on Hedgehog signaling. We combined the ease of manipulating chicken embryos with emerging knowledge of the chicken genome to reveal directly the basis of defective Hedgehog signal transduction in talpid(3) embryos and to identify the talpid(3) gene. We show in several regions of the embryo that the talpid(3) phenotype is completely ligand independent and demonstrate for the first time that talpid(3) is absolutely required for the function of both Gli repressor and activator in the intracellular Hedgehog pathway. We map the talpid(3) locus to chromosome 5 and find a frameshift mutation in a KIAA0586 ortholog (ENSGALG00000012025), a gene not previously attributed with any known function. We show a direct causal link between KIAA0586 and the mutant phenotype by rescue experiments. KIAA0586 encodes a novel protein, apparently specific to vertebrates, that localizes to the cytoplasm. We show that Gli3 processing is abnormal in talpid(3) mutant cells but that Gli3 can still translocate to the nucleus. These results suggest that the talpid(3) protein operates in the cytoplasm to regulate the activity of both Gli repressor and activator proteins
Two cilengitide regimens in combination with standard treatment for patients with newly diagnosed glioblastoma and unmethylated MGMT gene promoter: results of the open-label, controlled, randomized phase II CORE study
Background Survival outcomes for patients with glioblastoma remain poor, particularly for patients with unmethylated O6-methylguanine-DNA methyltransferase (MGMT) gene promoter. This phase II, randomized, open-label, multicenter trial investigated the efficacy and safety of 2 dose regimens of the selective integrin inhibitor cilengitide combined with standard chemoradiotherapy in patients with newly diagnosed glioblastoma and an unmethylated MGMT promoter. Methods Overall, 265 patients were randomized (1:1:1) to standard cilengitide (2000 mg 2×/wk; n = 88), intensive cilengitide (2000 mg 5×/wk during wk 1−6, thereafter 2×/wk; n = 88), or a control arm (chemoradiotherapy alone; n = 89). Cilengitide was administered intravenously in combination with daily temozolomide (TMZ) and concomitant radiotherapy (RT; wk 1−6), followed by TMZ maintenance therapy (TMZ/RT→TMZ). The primary endpoint was overall survival; secondary endpoints included progression-free survival, pharmacokinetics, and safety and tolerability. Results Median overall survival was 16.3 months in the standard cilengitide arm (hazard ratio [HR], 0.686; 95% CI: 0.484, 0.972; P = .032) and 14.5 months in the intensive cilengitide arm (HR, 0.858; 95% CI: 0.612, 1.204; P = .3771) versus 13.4 months in the control arm. Median progression-free survival assessed per independent review committee was 5.6 months (HR, 0.822; 95% CI: 0.595, 1.134) and 5.9 months (HR, 0.794; 95% CI: 0.575, 1.096) in the standard and intensive cilengitide arms, respectively, versus 4.1 months in the control arm. Cilengitide was well tolerated. Conclusions Standard and intensive cilengitide dose regimens were well tolerated in combination with TMZ/RT→TMZ. Inconsistent overall survival and progression-free survival outcomes and a limited sample size did not allow firm conclusions regarding clinical efficacy in this exploratory phase II stud
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