220 research outputs found
Adaptive Huber Regression
Big data can easily be contaminated by outliers or contain variables with
heavy-tailed distributions, which makes many conventional methods inadequate.
To address this challenge, we propose the adaptive Huber regression for robust
estimation and inference. The key observation is that the robustification
parameter should adapt to the sample size, dimension and moments for optimal
tradeoff between bias and robustness. Our theoretical framework deals with
heavy-tailed distributions with bounded -th moment for any . We establish a sharp phase transition for robust estimation of regression
parameters in both low and high dimensions: when , the estimator
admits a sub-Gaussian-type deviation bound without sub-Gaussian assumptions on
the data, while only a slower rate is available in the regime .
Furthermore, this transition is smooth and optimal. In addition, we extend the
methodology to allow both heavy-tailed predictors and observation noise.
Simulation studies lend further support to the theory. In a genetic study of
cancer cell lines that exhibit heavy-tailedness, the proposed methods are shown
to be more robust and predictive.Comment: final versio
Multiplexed entanglement swapping with atomic-ensemble-based quantum memories in the single excitation regime
Entanglement swapping (ES) between memory repeater links is critical for
establishing quantum networks via quantum repeaters. So far, ES with
atomic-ensemble-based memories has not been achieved. Here, we experimentally
demonstrated ES between two entangled pairs of spin-wave memories via
Duan-Lukin-Cirac-Zoller scheme. With a cloud of cold atoms inserted in a
cavity, we produce non-classically-correlated spin-wave-photon pairs in 12
spatial modes and then prepare two entangled pairs of spin-wave memories via a
multiplexed scheme. Via single-photon Bell measurement on retrieved fields from
two memories, we project the two remaining memories never entangled previously
into an entangled state with the measured concurrence of C = 0.0124(0.003). The
successful probability of ES in our scheme is increased by three times,
compared with that in non-multiplexed scheme. Our presented work shows that the
generation of entanglement (C>0) between the remaining memory ensembles
requires the average cross-correlation function of the spin-wave-photon pairs
to be >30
Magnetically assisted DNA assays: high selectivity using conjugated polymers for amplified fluorescent transduction
We report a strategy for conjugated polymer (CP)-based optical DNA detection with improved selectivity. The high sensitivity of CP-based biosensors arises from light harvesting by the CP and the related amplified fluorescent signal transduction. We demonstrate that the use of magnetic microparticles significantly improves the selectivity of this class of DNA sensors. Compared with previously reported DNA sensors with CP amplification, this novel sensing strategy displays excellent discrimination against non-cognate DNA in the presence of a protein mixture or even human serum. We also demonstrate that the magnetically assisted DNA sensor can conveniently identify even a single-nucleotide mismatch in the target sequence
Cavity-enhanced and spatial-multimode spin-wave-photon quantum interface
Practical realizations of quantum repeaters require quantum memory
simultaneously providing high retrieval efficiency, long lifetime and multimode
storages. So far, the combination of high retrieval efficiency and spatially
multiplexed storages into a single memory remains challenging. Here, we set up
a ring cavity that supports an array including 6 TEM00 modes and then
demonstrated cavity enhanced and spatially multiplexed spin wave photon quantum
interface (QI). The cavity arrangement is according to Fermat' optical theorem,
which enables the six modes to experience the same optical length per round
trip. Each mode includesn horizontal and vertical polarizations. Via DLCZ
process in a cold atomic ensemble, we create non classically correlated pairs
of spin waves and Stokes photons in the 12 modes. The retrieved fields from the
multiplexed SWs are enhanced by the cavity and the average intrinsic retrieval
efficiency reaches 70% at zero delay. The storage time for the case that
cross-correlation function of the multiplexed QI is beyond 2 reaches 0.6ms
G protein-coupled receptor 68 increases the number of B lymphocytes
G protein-coupled receptor 68 (GPR68) is a proton sensor that is activated upon binding to extracellular protons. We have previously found that GPR68 induces a proapoptotic pathway in bone marrow (BM) cells from the patients with myelodysplastic syndromes (MDS) after treated with lenalidomide. However, the function of GPR68 in normal hematopoietic cells remains unclear. With genetic loss of function approach, we found reduced frequency and number of B lymphocytes in the peripheral blood (PB) of whole body Gpr68-/- mice compared to control littermates upon aging. During hematopoietic regeneration, such as in response to fluorouracil (5-FU), we also found reduced frequency and number of B lymphocytes in Gpr68-/- mice compared to wild type mice. Mechanism studies revealed that Gpr68 expression was upregulated in B lymphocytes of BM during aging and in hematopoietic progenitor cells after treatment with 5-FU. In addition, activation of Gpr68 by its activators increased the frequency and number of B lymphocytes. Our studies indicate that Gpr68 expression is upregulated in hematopoietic cells upon aging and during hematopoietic regeneration that ends up with increased number of B lymphocytes
Inherited Cardiomyopathies: Genetics and Clinical Genetic Testing
Inherited cardiomyopathies are major causes of morbidity and mortality and include a group of cardiac disorders such as hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy, arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C), left ventricular noncompaction (LVNC), and restrictive cardiomyopathy (RCM). These diseases have a substantial genetic component and predispose to sudden cardiac death. Since the first gene was identified as a disease-causing gene for HCM over two decades ago, more than eighty genes have been identified to be associated with inherited cardiomyopathies and genetic testing has become prevalent in making clinical diagnosis. With the advent of next-generation sequencing technology, genetic panel testing of inherited cardiomyopathies has become feasible and cost efficient. In this review, we summarize the individual cardiomyopathies with the emphasis on cardiomyopathy genetics and genetic testing
The Biocompatibility of Nanodiamonds and Their Application in Drug Delivery Systems
Nanodiamonds (NDs), as a new member of the carbon nanoparticles family, have attracted more and more attention in biomedicine recently due to their excellent physical and chemical properties. This paper summarizes the main results from the in vitro and in vivo safety assessments of NDs and reports the application of NDs in the development of drug delivery systems. In view of the NDs' characteristics of easy formation of a porous cluster structure in solution, an adsorption model for a variety of functional molecules on the ND clusters is proposed, which provides new ideas for developing a novel smart drug with various features such as sustained-release, targeting, and fluorescence imaging
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