Realizing quantum speedup for practically relevant, computationally hard problems is a central challenge in quantum information science. Using Rydberg atom arrays with up to 289 qubits in two spatial ...dimensions, we experimentally investigate quantum algorithms for solving the Maximum Independent Set problem. We use a hardware-efficient encoding associated with Rydberg blockade, realize closed-loop optimization to test several variational algorithms, and subsequently apply them to systematically explore a class of graphs with programmable connectivity. We find the problem hardness is controlled by the solution degeneracy and number of local minima, and experimentally benchmark the quantum algorithm's performance against classical simulated annealing. On the hardest graphs, we observe a superlinear quantum speedup in finding exact solutions in the deep circuit regime and analyze its origins.
The muscleblind-like (Mbnl) family of RNA-binding proteins plays important roles in muscle and eye development and in myotonic dystrophy (DM), in which expanded CUG or CCUG repeats functionally ...deplete Mbnl proteins. We identified transcriptome-wide functional and biophysical targets of Mbnl proteins in brain, heart, muscle, and myoblasts by using RNA-seq and CLIP-seq approaches. This analysis identified several hundred splicing events whose regulation depended on Mbnl function in a pattern indicating functional interchangeability between Mbnl1 and Mbnl2. A nucleotide resolution RNA map associated repression or activation of exon splicing with Mbnl binding near either 3′ splice site or near the downstream 5′ splice site, respectively. Transcriptomic analysis of subcellular compartments uncovered a global role for Mbnls in regulating localization of mRNAs in both mouse and Drosophila cells, and Mbnl-dependent translation and protein secretion were observed for a subset of mRNAs with Mbnl-dependent localization. These findings hold several new implications for DM pathogenesis.
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► A nucleotide resolution RNA map of the splicing regulatory activity of Mbnl1 ► Functional interchangeability of Mbnl1 and Mbnl2 in splicing regulation ► A global role for Mbnls in regulating mRNA localization in mouse and fly ► Mbnl-dependent regulation of translation and protein secretion of Mbnl-bound mRNAs
Muscleblinds are a family of conserved RNA-binding proteins that are important in development and myotonic dystrophy. In addition to regulating alternative splicing of hundreds of exons, muscleblinds directly bind 3′ ends of mRNAs to regulate their subcellular localization and translation.
The most successful example of large lattice-mismatched epitaxial growth of semiconductors is the growth of III-nitrides on sapphire, leading to the award of the Nobel Prize in 2014 and great success ...in developing InGaN-based blue emitters. However, the majority of achievements in the field of III-nitride optoelectronics are mainly limited to polar GaN grown on c-plane (0001) sapphire. This polar orientation poses a number of fundamental issues, such as reduced quantum efficiency, efficiency droop, green and yellow gap in wavelength coverage, etc. To date, it is still a great challenge to develop longer wavelength devices such as green and yellow emitters. One clear way forward would be to grow III-nitride device structures along a semi-/non-polar direction, in particular, a semi-polar orientation, which potentially leads to both enhanced indium incorporation into GaN and reduced quantum confined Stark effects. This review presents recent progress on developing semi-polar GaN overgrowth technologies on sapphire or Si substrates, the two kinds of major substrates which are cost-effective and thus industry-compatible, and also demonstrates the latest achievements on electrically injected InGaN emitters with long emission wavelengths up to and including amber on overgrown semi-polar GaN. Finally, this review presents a summary and outlook on further developments for semi-polar GaN based optoelectronics.
Our current knowledge of cosmic star-formation history during the first two billion years (corresponding to redshift z > 3) is mainly based on galaxies identified in rest-frame ultraviolet light
. ...However, this population of galaxies is known to under-represent the most massive galaxies, which have rich dust content and/or old stellar populations. This raises the questions of the true abundance of massive galaxies and the star-formation-rate density in the early Universe. Although several massive galaxies that are invisible in the ultraviolet have recently been confirmed at early epochs
, most of them are extreme starburst galaxies with star-formation rates exceeding 1,000 solar masses per year, suggesting that they are unlikely to represent the bulk population of massive galaxies. Here we report submillimetre (wavelength 870 micrometres) detections of 39 massive star-forming galaxies at z > 3, which are unseen in the spectral region from the deepest ultraviolet to the near-infrared. With a space density of about 2 × 10
per cubic megaparsec (two orders of magnitude higher than extreme starbursts
) and star-formation rates of 200 solar masses per year, these galaxies represent the bulk population of massive galaxies that has been missed from previous surveys. They contribute a total star-formation-rate density ten times larger than that of equivalently massive ultraviolet-bright galaxies at z > 3. Residing in the most massive dark matter haloes at their redshifts, they are probably the progenitors of the largest present-day galaxies in massive groups and clusters. Such a high abundance of massive and dusty galaxies in the early Universe challenges our understanding of massive-galaxy formation.
Quantum spin liquids, exotic phases of matter with topological order, have been a major focus in physics for the past several decades. Such phases feature long-range quantum entanglement that can ...potentially be exploited to realize robust quantum computation. We used a 219-atom programmable quantum simulator to probe quantum spin liquid states. In our approach, arrays of atoms were placed on the links of a kagome lattice, and evolution under Rydberg blockade created frustrated quantum states with no local order. The onset of a quantum spin liquid phase of the paradigmatic toric code type was detected by using topological string operators that provide direct signatures of topological order and quantum correlations. Our observations enable the controlled experimental exploration of topological matter and protected quantum information processing.
The Davis—Kahan theorem is used in the analysis of many statistical procedures to bound the distance between subspaces spanned by population eigenvectors and their sample versions. It relies on an ...eigenvalue separation condition between certain population and sample eigenvalues. We present a variant of this result that depends only on a population eigenvalue separation condition, making it more natural and convenient for direct application in statistical contexts, and provide an improvement in many cases to the usual bound in the statistical literature. We also give an extension to situations where the matrices under study may be asymmetric or even non-square, and where interest is in the distance between subspaces spanned by corresponding singular vectors.
Programmed cell death (PCD), referring to apoptosis, autophagy and programmed necrosis, is proposed to be death of a cell in any pathological format, when mediated by an intracellular program. These ...three forms of PCD may jointly decide the fate of cells of malignant neoplasms; apoptosis and programmed necrosis invariably contribute to cell death, whereas autophagy can play either pro‐survival or pro‐death roles. Recent bulk of accumulating evidence has contributed to a wealth of knowledge facilitating better understanding of cancer initiation and progression with the three distinctive types of cell death. To be able to decipher PCD signalling pathways may aid development of new targeted anti‐cancer therapeutic strategies. Thus in this review, we present a brief outline of apoptosis, autophagy and programmed necrosis pathways and apoptosis‐related microRNA regulation, in cancer. Taken together, understanding PCD and the complex interplay between apoptosis, autophagy and programmed necrosis may ultimately allow scientists and clinicians to harness the three types of PCD for discovery of further novel drug targets, in the future cancer treatment.
Multigene and genomic data sets have become commonplace in the field of phylogenetics, but many existing tools are not designed for such data sets, which often makes the analysis time‐consuming and ...tedious. Here, we present PhyloSuite, a (cross‐platform, open‐source, stand‐alone Python graphical user interface) user‐friendly workflow desktop platform dedicated to streamlining molecular sequence data management and evolutionary phylogenetics studies. It uses a plugin‐based system that integrates several phylogenetic and bioinformatic tools, thereby streamlining the entire procedure, from data acquisition to phylogenetic tree annotation (in combination with iTOL). It has the following features: (a) point‐and‐click and drag‐and‐drop graphical user interface; (b) a workplace to manage and organize molecular sequence data and results of analyses; (c) GenBank entry extraction and comparative statistics; and (d) a phylogenetic workflow with batch processing capability, comprising sequence alignment (mafft and macse), alignment optimization (trimAl, HmmCleaner and Gblocks), data set concatenation, best partitioning scheme and best evolutionary model selection (PartitionFinder and modelfinder), and phylogenetic inference (MrBayes and iq‐tree). PhyloSuite is designed for both beginners and experienced researchers, allowing the former to quick‐start their way into phylogenetic analysis, and the latter to conduct, store and manage their work in a streamlined way, and spend more time investigating scientific questions instead of wasting it on transferring files from one software program to another.
We present a new, publicly available library of dust spectral energy distributions (SEDs). These SEDs are characterized by only three parameters: the dust mass (Mdust), the dust temperature (Tdust), ...and the mid-to-total infrared color (IR8 ≡ LIR/L8). The latter measures the relative contribution of polycyclic aromatic hydrocarbon (PAH) molecules to the total infrared luminosity. We used this library to model star-forming galaxies at 0.5 < z < 4 in the deep CANDELS fields, using both individual detections and stacks of Herschel and ALMA imaging, and extending this sample to z = 0 using the Herschel Reference Survey. At first order, the dust SED of a galaxy was observed to be independent of stellar mass, but evolving with redshift. We found trends of increasing Tdust and IR8 with redshift and distance from the SFR–M∗ main sequence, and quantified for the first time their intrinsic scatter. Half of the observed variations of these parameters was captured by the above empirical relations, and after subtracting the measurement errors we found residual scatters of ΔTdust/Tdust = 12% and Δlog IR8 = 0.18 dex. We observed second order variations with stellar mass: massive galaxies (M∗ > 1011M⊙) at z ≤ 1 have slightly lower temperatures indicative of a reduced star formation efficiency, while low mass galaxies (M∗ < 1010M⊙) at z ≥ 1 showed reduced PAH emission, possibly linked to their lower metallicities. Building on these results, we constructed high-fidelity mock galaxy catalogs to predict the accuracy of infrared luminosities and dust masses determined using a single broadband measurement. Using a single James Webb Space Telescope (JWST) MIRI band, we found that LIR is typically uncertain by 0.15 dex, with a maximum of 0.25 dex when probing the rest-frame 8 μm, and this is not significantly impacted by typical redshift uncertainties. On the other hand, we found that ALMA bands 8 to 7 and 6 to 3 measured the dust mass at better than 0.2 and 0.15 dex, respectively, and independently of redshift, while bands 9 to 6 only measured LIR at better than 0.2 dex at z > 1, 3.2, 3.8, and 5.7, respectively. Starburst galaxies had their LIR significantly underestimated when measured by a single JWST or ALMA band, while their dust mass from a single ALMA band were moderately overestimated. This dust library and the results of this paper can be used immediately to improve the design of observing proposals, and interpret more accurately the large amount of archival data from Spitzer, Herschel and ALMA.
Abstract
Myotonic dystrophy (dystrophia myotonica, DM) is a multi-systemic disease caused by expanded CTG or CCTG microsatellite repeats. Characterized by symptoms in muscle, heart and central ...nervous system, among others, it is one of the most variable diseases known. A major pathogenic event in DM is the sequestration of muscleblind-like proteins by CUG or CCUG repeat-containing RNAs transcribed from expanded repeats, and differences in the extent of MBNL sequestration dependent on repeat length and expression level may account for some portion of the variability. However, many other cellular pathways are reported to be perturbed in DM, and the severity of specific disease symptoms varies among individuals. To help understand this variability and facilitate research into DM, we generated 120 RNASeq transcriptomes from skeletal and heart muscle derived from healthy and DM1 biopsies and autopsies. A limited number of DM2 and Duchenne muscular dystrophy samples were also sequenced. We analyzed splicing and gene expression, identified tissue-specific changes in RNA processing and uncovered transcriptome changes strongly correlating with muscle strength. We created a web resource at http://DMseq.org that hosts raw and processed transcriptome data and provides a lightweight, responsive interface that enables browsing of processed data across the genome.
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