2,864 research outputs found
Dipole portal to heavy neutral leptons
We consider generic neutrino dipole portals between left-handed neutrinos,
photons, and right-handed heavy neutral leptons (HNL) with Dirac masses. The
dominance of this portal significantly alters the conventional phenomenology of
HNLs. We derive a comprehensive set of constraints on the dipole portal to HNLs
by utilizing data from LEP, LHC, MiniBooNE, LSND as well as observations of
Supernova 1987A and consistency of the standard Big Bang Nucleosynthesis. We
calculate projected sensitivities from the proposed high-intensity SHiP beam
dump experiment, and the ongoing experiments at the Short-Baseline Neutrino
facility at Fermilab. Dipole mediated Primakoff neutrino upscattering and
Dalitz-like meson decays are found to be the main production mechanisms in most
of the parametric regime under consideration. Proposed explanations of LSND and
MiniBooNE anomalies based on HNLs with dipole-induced decays are found to be
severely constrained, or to be tested in the future experiments.Comment: 26 pages, 11 figure
DeepAdjoint: An All-in-One Photonic Inverse Design Framework Integrating Data-Driven Machine Learning with Optimization Algorithms
In recent years, hybrid design strategies combining machine learning (ML)
with electromagnetic optimization algorithms have emerged as a new paradigm for
the inverse design of photonic structures and devices. While a trained,
data-driven neural network can rapidly identify solutions near the global
optimum with a given dataset's design space, an iterative optimization
algorithm can further refine the solution and overcome dataset limitations.
Furthermore, such hybrid ML-optimization methodologies can reduce computational
costs and expedite the discovery of novel electromagnetic components. However,
existing hybrid ML-optimization methods have yet to optimize across both
materials and geometries in a single integrated and user-friendly environment.
In addition, due to the challenge of acquiring large datasets for ML, as well
as the exponential growth of isolated models being trained for photonics
design, there is a need to standardize the ML-optimization workflow while
making the pre-trained models easily accessible. Motivated by these challenges,
here we introduce DeepAdjoint, a general-purpose, open-source, and
multi-objective "all-in-one" global photonics inverse design application
framework which integrates pre-trained deep generative networks with
state-of-the-art electromagnetic optimization algorithms such as the adjoint
variables method. DeepAdjoint allows a designer to specify an arbitrary optical
design target, then obtain a photonic structure that is robust to fabrication
tolerances and possesses the desired optical properties - all within a single
user-guided application interface. Our framework thus paves a path towards the
systematic unification of ML and optimization algorithms for photonic inverse
design
Selection of chromosomal DNA libraries using a multiplex CRISPR system.
The directed evolution of biomolecules to improve or change their activity is central to many engineering and synthetic biology efforts. However, selecting improved variants from gene libraries in living cells requires plasmid expression systems that suffer from variable copy number effects, or the use of complex marker-dependent chromosomal integration strategies. We developed quantitative gene assembly and DNA library insertion into the Saccharomyces cerevisiae genome by optimizing an efficient single-step and marker-free genome editing system using CRISPR-Cas9. With this Multiplex CRISPR (CRISPRm) system, we selected an improved cellobiose utilization pathway in diploid yeast in a single round of mutagenesis and selection, which increased cellobiose fermentation rates by over 10-fold. Mutations recovered in the best cellodextrin transporters reveal synergy between substrate binding and transporter dynamics, and demonstrate the power of CRISPRm to accelerate selection experiments and discoveries of the molecular determinants that enhance biomolecule function
New Constraints on Millicharged Particles from Cosmic-ray Production
We study the production of exotic millicharged particles (MCPs) from cosmic
ray-atmosphere collisions which constitutes a permanent MCP production source
for all terrestrial experiments Our calculation of the MCP flux can be used to
reinterpret existing limits from experiments such as MACRO and Majorana on an
ambient flux of ionizing particles. Large-scale underground neutrino detectors
are particularly favorable targets for the resulting MCPs. Using available data
from the Super-K experiment, we set new limits on MCPs, which are the best in
sensitivity reach for the mass range GeV,
and which are competitive with accelerator-based searches for masses up to 1.5
GeV. Applying these constraints to models where a sub-dominant component of
dark matter (DM) is fractionally charged allows us to probe parts of the
parameter space that are challenging for conventional direct-detection DM
experiments, independently of any assumptions about the DM abundance. These
results can be further improved with the next generation of large-scale
neutrino detectors.Comment: 6 pages + 5 pages appendix, 11 figures. Fixed erroneously digitized
ArgoNeuT data in Fig 1. Typo fixed in Eq.(B4
Glial βii spectrin contributes to paranode formation and maintenance
Action potential conduction along myelinated axons depends on high densities of voltage-gated Na channels at the nodes of Ranvier. Flanking each node, paranodal junctions (paranodes) are formed between axons and Schwann cells in the peripheral nervous system (PNS) or oligodendrocytes intheCNS. Paranodal junctions contribute to both no deassembly and maintenance. Despitetheir importance, the molecular mechanisms responsible for paranode assembly and maintenance remain poorly understood. βII spectrin is expressed in diverse cells and is an essential part of the submembranous cytoskeleton. Here, we show that Schwann cell βII spectrin is highly enriched at paranodes. To elucidate the roles of glial βII spectrin, we generated mutant mice lacking βII spectrin in myelinating glial cells by crossing mice with a floxed allele of Sptbn1 with Cnp-Cre mice, and analyzed both male and female mice. Juvenile (4 weeks) and middle-aged (60 weeks) mutant mice showed reduced grip strength and sciatic nerve conduction slowing, whereas no phenotype was observed between 8 and 24 weeks of age. Consistent with these findings, immunofluorescence microscopy revealed disorganized paranodes in the PNS and CNS of both postnatal day 13 and middle-aged mutant mice, but not in young adult mutant mice. Electron microscopy confirmed partial loss of transverse bands at the paranodal axoglial junction in the middle-aged mutant mice in both the PNS and CNS. These findings demonstrate that a spectrin-based cytoskeleton in myelinating glia contributes to formation and maintenance of paranodal junctions.Fil: Susuki, Keiichiro. Baylor College of Medicine; Estados UnidosFil: Zollinger, Daniel R.. Baylor College of Medicine; Estados UnidosFil: Chang, Kae Jiun. Baylor College of Medicine; Estados UnidosFil: Zhang, Chuansheng. Baylor College of Medicine; Estados UnidosFil: Huang, Claire Yu Mei. Baylor College of Medicine; Estados UnidosFil: Tsai, Chang Ru. Baylor College of Medicine; Estados UnidosFil: Galiano, Mauricio Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; Argentina. Baylor College of Medicine; Estados UnidosFil: Liu, Yanhong. Baylor College of Medicine; Estados UnidosFil: Benusa, Savannah D.. Virginia Commonwealth University; Estados UnidosFil: Yermakov, Leonid M.. Wright State University; Estados UnidosFil: Griggs, Ryan B.. Wright State University; Estados UnidosFil: Dupree, Jeffrey L.. Virginia Commonwealth University; Estados UnidosFil: Rasband, Matthew N.. Baylor College of Medicine; Estados Unido
Public Health Implications of Evictions: Modeling the Costs for Landlords, Tenants, and Society
In the United States, more than 13% of renters experience a formal or informal eviction in their lifetime. Forced moves contribute to a decline in job status, mental and physical health, material possessions, safety, social networks, housing aid, and neighborhood stability. Previous research has explored the risk factors, causes, and costs to those burdened by evictions. However, the costs of evictions incurred by all stakeholders involved in the process of evictions and homelessness remain largely unexplored. The homeownership rate in New Haven is less than 30%, and more than 52% of households are ‘cost-burdened,’ meaning more than 30% of income “is spent on housing costs associated with owning or renting a home.” Thus, this project set out to analyze the contributing burdens of costs within New Haven, Connecticut.https://elischolar.library.yale.edu/ysph_pbchrr/1016/thumbnail.jp
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