Showing papers by "Georgia Institute of Technology published in 2013"
TL;DR: In this article, the Streptococcus pyogenes Cas9 (SpCas9) nuclease can be efficiently targeted to genomic loci by means of single-guide RNAs (sgRNAs) to enable genome editing.
Abstract: The Streptococcus pyogenes Cas9 (SpCas9) nuclease can be efficiently targeted to genomic loci by means of single-guide RNAs (sgRNAs) to enable genome editing. Here, we characterize SpCas9 targeting specificity in human cells to inform the selection of target sites and avoid off-target effects. Our study evaluates >700 guide RNA variants and SpCas9-induced indel mutation levels at >100 predicted genomic off-target loci in 293T and 293FT cells. We find that SpCas9 tolerates mismatches between guide RNA and target DNA at different positions in a sequence-dependent manner, sensitive to the number, position and distribution of mismatches. We also show that SpCas9-mediated cleavage is unaffected by DNA methylation and that the dosage of SpCas9 and sgRNA can be titrated to minimize off-target modification. To facilitate mammalian genome engineering applications, we provide a web-based software tool to guide the selection and validation of target sequences as well as off-target analyses.
4,113 citations
01 Sep 2013
TL;DR: It is found that SpCas9 tolerates mismatches between guide RNA and target DNA at different positions in a sequence-dependent manner, sensitive to the number, position and distribution of mismatches.
Abstract: The Streptococcus pyogenes Cas9 (SpCas9) nuclease can be efficiently targeted to genomic loci by means of single-guide RNAs (sgRNAs) to enable genome editing. Here, we characterize SpCas9 targeting specificity in human cells to inform the selection of target sites and avoid off-target effects. Our study evaluates >700 guide RNA variants and SpCas9-induced indel mutation levels at >100 predicted genomic off-target loci in 293T and 293FT cells. We find that SpCas9 tolerates mismatches between guide RNA and target DNA at different positions in a sequence-dependent manner, sensitive to the number, position and distribution of mismatches. We also show that SpCas9-mediated cleavage is unaffected by DNA methylation and that the dosage of SpCas9 and sgRNA can be titrated to minimize off-target modification. To facilitate mammalian genome engineering applications, we provide a web-based software tool to guide the selection and validation of target sequences as well as off-target analyses.
3,421 citations
University of Western Ontario1, York University2, The Mind Research Network3, University of Bergen4, National Institutes of Health5, University of New Mexico6, University of Chieti-Pescara7, Washington University in St. Louis8, Stanford University9, Georgia Institute of Technology10, Oulu University Hospital11, Indiana University12, Leibniz Institute for Neurobiology13, Otto-von-Guericke University Magdeburg14
TL;DR: Emerging evidence suggests that dynamic FC metrics may index changes in macroscopic neural activity patterns underlying critical aspects of cognition and behavior, though limitations with regard to analysis and interpretation remain.
2,332 citations
TL;DR: This paper reviews the fundamentals of the TENG in the three basic operation modes: vertical contact-separation mode, in-plane sliding mode, and single-electrode mode and predicts that a better enhancement of the output power density will be achieved in the next few years.
Abstract: Triboelectrification is an effect that is known to each and every one probably since ancient Greek time, but it is usually taken as a negative effect and is avoided in many technologies. We have recently invented a triboelectric nanogenerator (TENG) that is used to convert mechanical energy into electricity by a conjunction of triboelectrification and electrostatic induction. As for this power generation unit, in the inner circuit, a potential is created by the triboelectric effect due to the charge transfer between two thin organic/inorganic films that exhibit opposite tribo-polarity; in the outer circuit, electrons are driven to flow between two electrodes attached on the back sides of the films in order to balance the potential. Since the most useful materials for TENG are organic, it is also named organic nanogenerator, which is the first using organic materials for harvesting mechanical energy. In this paper, we review the fundamentals of the TENG in the three basic operation modes: vertical contact-...
2,102 citations
California Institute of Technology1, Lawrence Livermore National Laboratory2, University of California, Berkeley3, Technical University of Denmark4, Columbia University5, Goddard Space Flight Center6, INAF7, SLAC National Accelerator Laboratory8, McGill University9, Hoffmann-La Roche10, University of Toulouse11, Inter-University Centre for Astronomy and Astrophysics12, Durham University13, Sonoma State University14, Roma Tre University15, Santa Cruz Institute for Particle Physics16, Georgia Institute of Technology17, Pontifical Catholic University of Chile18, Pennsylvania State University19, Harvard University20, Massachusetts Institute of Technology21, University of Cambridge22, Virginia Tech23, Los Alamos National Laboratory24, Quest University25, University of Michigan26, Weizmann Institute of Science27, North Carolina State University28, Willamette University29, University of Concepción30, Yale University31
TL;DR: The Nuclear Spectroscopic Telescope Array (NuSTAR) as discussed by the authors is the first focusing high-energy X-ray telescope in orbit, which operates in the band from 3 to 79 keV.
Abstract: The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates in the band from 3 to 79 keV, extending the sensitivity of focusing far beyond the ~10 keV high-energy cutoff achieved by all previous X-ray satellites. The inherently low background associated with concentrating the X-ray light enables NuSTAR to probe the hard X-ray sky with a more than 100-fold improvement in sensitivity over the collimated or coded mask instruments that have operated in this bandpass. Using its unprecedented combination of sensitivity and spatial and spectral resolution, NuSTAR will pursue five primary scientific objectives: (1) probe obscured active galactic nucleus (AGN) activity out to the peak epoch of galaxy assembly in the universe (at z ≾ 2) by surveying selected regions of the sky; (2) study the population of hard X-ray-emitting compact objects in the Galaxy by mapping the central regions of the Milky Way; (3) study the non-thermal radiation in young supernova remnants, both the hard X-ray continuum and the emission from the radioactive element ^(44)Ti; (4) observe blazars contemporaneously with ground-based radio, optical, and TeV telescopes, as well as with Fermi and Swift, to constrain the structure of AGN jets; and (5) observe line and continuum emission from core-collapse supernovae in the Local Group, and from nearby Type Ia events, to constrain explosion models. During its baseline two-year mission, NuSTAR will also undertake a broad program of targeted observations. The observatory consists of two co-aligned grazing-incidence X-ray telescopes pointed at celestial targets by a three-axis stabilized spacecraft. Deployed into a 600 km, near-circular, 6° inclination orbit, the observatory has now completed commissioning, and is performing consistent with pre-launch expectations. NuSTAR is now executing its primary science mission, and with an expected orbit lifetime of 10 yr, we anticipate proposing a guest investigator program, to begin in late 2014.
1,966 citations
Alternatives1, John Innes Centre2, University of Bonn3, University of North Carolina at Chapel Hill4, University of Wisconsin-Madison5, University of Utah6, University of Southern California7, University of Edinburgh8, University of Warwick9, Harvard University10, University College Cork11, University of Queensland12, University of Hertfordshire13, University of Potsdam14, University of California, San Diego15, Goethe University Frankfurt16, University of California, San Francisco17, University of Delaware18, Uppsala University19, Medical University of Vienna20, J. Craig Venter Institute21, University of Hawaii at Manoa22, Leibniz Association23, University of Iowa24, University of Aberdeen25, Georgia Institute of Technology26, University of California, Berkeley27, University of Groningen28, Princeton University29, University of Marburg30, University of Illinois at Urbana–Champaign31, Saarland University32, Norwegian University of Life Sciences33, Massey University34, Toyama Prefectural University35, ETH Zurich36, University of Saskatchewan37, Rutgers University38, Scripps Research Institute39, University of Helsinki40, Texas A&M University41, National Institutes of Health42, Technical University of Berlin43, University of Otago44, University of Cambridge45, University of Alberta46, Michigan State University47, Hofstra University48
TL;DR: This review presents recommended nomenclature for the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), a rapidly growing class of natural products.
1,560 citations
University of Adelaide1, University of Wisconsin-Madison2, Ghent University3, University of Canterbury4, University of Geneva5, Humboldt University of Berlin6, University of California, Irvine7, University of Mainz8, University of California, Berkeley9, Ohio State University10, Université libre de Bruxelles11, Ruhr University Bochum12, University of Wuppertal13, University of Maryland, College Park14, University of Kansas15, Lawrence Berkeley National Laboratory16, RWTH Aachen University17, Uppsala University18, University of Alberta19, Stockholm University20, Vrije Universiteit Brussel21, University of Bonn22, École Polytechnique Fédérale de Lausanne23, Georgia Institute of Technology24, Pennsylvania State University25, Technical University of Dortmund26, Southern University and A&M College27
TL;DR: The presence of a high-energy neutrino flux containing the most energetic neutrinos ever observed is revealed, including 28 events at energies between 30 and 1200 TeV, although the origin of this flux is unknown and the findings are consistent with expectations for a neutRino population with origins outside the solar system.
Abstract: We report on results of an all-sky search for high-energy neutrino events interacting within the IceCube neutrino detector conducted between May 2010 and May 2012. The search follows up on the previous detection of two PeV neutrino events, with improved sensitivity and extended energy coverage down to about 30 TeV. Twenty-six additional events were observed, substantially more than expected from atmospheric backgrounds. Combined, both searches reject a purely atmospheric origin for the 28 events at the 4 sigma level. These 28 events, which include the highest energy neutrinos ever observed, have flavors, directions, and energies inconsistent with those expected from the atmospheric muon and neutrino backgrounds. These properties are, however, consistent with generic predictions for an additional component of extraterrestrial origin.
1,490 citations
TL;DR: In this paper, a two-stage adaptive robust unit commitment model for the security constrained unit commitment problem in the presence of nodal net injection uncertainty is proposed, which only requires a deterministic uncertainty set, rather than a hard-to-obtain probability distribution on the uncertain data.
Abstract: Unit commitment, one of the most critical tasks in electric power system operations, faces new challenges as the supply and demand uncertainty increases dramatically due to the integration of variable generation resources such as wind power and price responsive demand. To meet these challenges, we propose a two-stage adaptive robust unit commitment model for the security constrained unit commitment problem in the presence of nodal net injection uncertainty. Compared to the conventional stochastic programming approach, the proposed model is more practical in that it only requires a deterministic uncertainty set, rather than a hard-to-obtain probability distribution on the uncertain data. The unit commitment solutions of the proposed model are robust against all possible realizations of the modeled uncertainty. We develop a practical solution methodology based on a combination of Benders decomposition type algorithm and the outer approximation technique. We present an extensive numerical study on the real-world large scale power system operated by the ISO New England. Computational results demonstrate the economic and operational advantages of our model over the traditional reserve adjustment approach.
1,454 citations
TL;DR: In this paper, a theoretical model for contact-mode TENGs was constructed based on the theoretical model, its real-time output characteristics and the relationship between the optimum resistance and TENG parameters were derived.
Abstract: A theoretical model for contact-mode TENGs was constructed in this paper. Based on the theoretical model, its real-time output characteristics and the relationship between the optimum resistance and TENG parameters were derived. The theory presented here is the first in-depth interpretation of the contact-mode TENG, which can serve as important guidance for rational design of the TENG structure in specific applications.
1,246 citations
TL;DR: Three problems in network management are identified: enabling frequent changes to network conditions and state, providing support for network configuration in a highlevel language, and providing better visibility and control over tasks for performing network diagnosis and troubleshooting.
Abstract: Network management is challenging. To operate, maintain, and secure a communication network, network operators must grapple with low-level vendor-specific configuration to implement complex high-level network policies. Despite many previous proposals to make networks easier to manage, many solutions to network management problems amount to stop-gap solutions because of the difficulty of changing the underlying infrastructure. The rigidity of the underlying infrastructure presents few possibilities for innovation or improvement, since network devices have generally been closed, proprietary, and vertically integrated. A new paradigm in networking, software defined networking (SDN), advocates separating the data plane and the control plane, making network switches in the data plane simple packet forwarding devices and leaving a logically centralized software program to control the behavior of the entire network. SDN introduces new possibilities for network management and configuration methods. In this article, we identify problems with the current state-of-the-art network configuration and management mechanisms and introduce mechanisms to improve various aspects of network management. We focus on three problems in network management: enabling frequent changes to network conditions and state, providing support for network configuration in a highlevel language, and providing better visibility and control over tasks for performing network diagnosis and troubleshooting. The technologies we describe enable network operators to implement a wide range of network policies in a high-level policy language and easily determine sources of performance problems. In addition to the systems themselves, we describe various prototype deployments in campus and home networks that demonstrate how SDN can improve common network management tasks.
1,122 citations
TL;DR: The ring-LWE distribution is pseudorandom as discussed by the authors, assuming that worst-case problems on ideal lattices are hard for polynomial-time quantum algorithms, which is not the case.
Abstract: The “learning with errors” (LWE) problem is to distinguish random linear equations, which have been perturbed by a small amount of noise, from truly uniform ones. The problem has been shown to be as hard as worst-case lattice problems, and in recent years it has served as the foundation for a plethora of cryptographic applications. Unfortunately, these applications are rather inefficient due to an inherent quadratic overhead in the use of LWE. A main open question was whether LWE and its applications could be made truly efficient by exploiting extra algebraic structure, as was done for lattice-based hash functions (and related primitives).We resolve this question in the affirmative by introducing an algebraic variant of LWE called ring-LWE, and proving that it too enjoys very strong hardness guarantees. Specifically, we show that the ring-LWE distribution is pseudorandom, assuming that worst-case problems on ideal lattices are hard for polynomial-time quantum algorithms. Applications include the first truly practical lattice-based public-key cryptosystem with an efficient security reduction; moreover, many of the other applications of LWE can be made much more efficient through the use of ring-LWE.
TL;DR: An analytical framework is developed for interrogation of subsurface microbial communities distributed across two geologically distinct formations of the unconfined aquifer underlying the Hanford Site in southeastern Washington State that quantitatively estimate influences of Drift, Selection and Dispersal.
Abstract: Spatial turnover in the composition of biological communities is governed by (ecological) Drift, Selection and Dispersal. Commonly applied statistical tools cannot quantitatively estimate these processes, nor identify abiotic features that impose these processes. For interrogation of subsurface microbial communities distributed across two geologically distinct formations of the unconfined aquifer underlying the Hanford Site in southeastern Washington State, we developed an analytical framework that advances ecological understanding in two primary ways. First, we quantitatively estimate influences of Drift, Selection and Dispersal. Second, ecological patterns are used to characterize measured and unmeasured abiotic variables that impose Selection or that result in low levels of Dispersal. We find that (i) Drift alone consistently governs ∼25% of spatial turnover in community composition; (ii) in deeper, finer-grained sediments, Selection is strong (governing ∼60% of turnover), being imposed by an unmeasured but spatially structured environmental variable; (iii) in shallower, coarser-grained sediments, Selection is weaker (governing ∼30% of turnover), being imposed by vertically and horizontally structured hydrological factors;(iv) low levels of Dispersal can govern nearly 30% of turnover and be caused primarily by spatial isolation resulting from limited exchange between finer and coarser-grain sediments; and (v) highly permeable sediments are associated with high levels of Dispersal that homogenize community composition and govern over 20% of turnover. We further show that our framework provides inferences that cannot be achieved using preexisting approaches, and suggest that their broad application will facilitate a unified understanding of microbial communities.
TL;DR: It is concluded that cell-type-specific chromatin organization occurs at the submegabase scale and that architectural proteins shape the genome in hierarchical length scales.
TL;DR: This work demonstrated the practicability of using NG to harvest large-scale mechanical energy, such as footsteps, rolling wheels, wind power, and ocean waves, by constructing a triboelectric nanogenerator with ultrahigh electric output.
Abstract: This article describes a simple, cost-effective, and scalable approach to fabricate a triboelectric nanogenerator (NG) with ultrahigh electric output. Triggered by commonly available ambient mechanical energy such as human footfalls, a NG with size smaller than a human palm can generate maximum short-circuit current of 2 mA, delivering instantaneous power output of 1.2 W to external load. The power output corresponds to an area power density of 313 W/m2 and a volume power density of 54 268 W/m3 at an open-circuit voltage of ∼1200 V. An energy conversion efficiency of 14.9% has been achieved. The power was capable of instantaneously lighting up as many as 600 multicolor commercial LED bulbs. The record high power output for the NG is attributed to optimized structure, proper materials selection and nanoscale surface modification. This work demonstrated the practicability of using NG to harvest large-scale mechanical energy, such as footsteps, rolling wheels, wind power, and ocean waves.
TL;DR: The results showed that justice-performance relationships were mediated by positive and negative affect, with the relevant affect dimension varying across justice and performance variables, and the merit in integrating the social exchange and affect lenses in future research is discussed.
Abstract: Although a flurry of meta-analyses summarized the justice literature at the turn of the millennium, interest in the topic has surged in the decade since. In particular, the past decade has witnessed the rise of social exchange theory as the dominant lens for examining reactions to justice, and the emergence of affect as a complementary lens for understanding such reactions. The purpose of this meta-analytic review was to test direct, mediating, and moderating hypotheses that were inspired by those 2 perspectives, to gauge their adequacy as theoretical guides for justice research. Drawing on a review of 493 independent samples, our findings revealed a number of insights that were not included in prior meta-analyses. With respect to social exchange theory, our results revealed that the significant relationships between justice and both task performance and citizenship behavior were mediated by indicators of social exchange quality (trust, organizational commitment, perceived organizational support, and leader‐member exchange), though such mediation was not apparent for counterproductive behavior. The strength of those relationships did not vary according to whether the focus of the justice matched the target of the performance behavior, contrary to popular assumptions in the literature, or according to whether justice was referenced to a specific event or a more general entity. With respect to affect, our results showed that justice‐performance relationships were mediated by positive and negative affect, with the relevant affect dimension varying across justice and performance variables. Our discussion of these findings focuses on the merit in integrating the social exchange and affect lenses in future research.
TL;DR: These technologies such as multiple-input multiple-output (MIMO) and orthogonal frequency division multiplexing (OFDM), cognitive radio, network coding, cooperative communication, etc.
Abstract: Reducing energy consumption in wireless communications has attracted increasing attention recently. Advanced physical layer techniques such as multiple-input multiple-output (MIMO) and orthogonal frequency division multiplexing (OFDM), cognitive radio, network coding, cooperative communication, etc.; new network architectures such as heterogeneous networks, distributed antennas, multi-hop cellulars, etc.; as well as radio and network resource management schemes such as various cross-layer optimization algorithms, dynamic power saving, multiple radio access technologies coordination, etc. have been proposed to address this issue. In this article, we overview these technologies and present the state-of-the-art on each aspect. Some challenges that need to be solved in the area are also described.
TL;DR: A series of flexible nanocomposite electrodes were fabricated by facile electro-deposition of cobalt and nickel double hydroxide (DH) nanosheets on porous NiCo2O4 nanowires grown radially on carbon fiber paper (CFP) for high capacity, high energy, and power density supercapacitors.
Abstract: A series of flexible nanocomposite electrodes were fabricated by facile electro-deposition of cobalt and nickel double hydroxide (DH) nanosheets on porous NiCo2O4 nanowires grown radially on carbon fiber paper (CFP) for high capacity, high energy, and power density supercapacitors. Among different stoichiometries of CoxNi1–xDH nanosheets studied, Co0.67Ni0.33 DHs/NiCo2O4/CFP hybrid nanoarchitecture showed the best cycling stability while maintaining high capacitance of ∼1.64 F/cm2 at 2 mA/cm2. This hybrid composite electrode also exhibited excellent rate capability; the areal capacitance decreased less than 33% as the current density was increased from 2 to 90 mA/cm2, offering excellent specific energy density (∼33 Wh/kg) and power density (∼41.25 kW/kg) at high cycling rates (up to150 mA/cm2).
TL;DR: It is demonstrated that popular initialization methods often perform poorly and that there are in fact strong alternatives to these methods, and eight commonly used linear time complexity initialization methods are compared.
Abstract: K-means is undoubtedly the most widely used partitional clustering algorithm. Unfortunately, due to its gradient descent nature, this algorithm is highly sensitive to the initial placement of the cluster centers. Numerous initialization methods have been proposed to address this problem. In this paper, we first present an overview of these methods with an emphasis on their computational efficiency. We then compare eight commonly used linear time complexity initialization methods on a large and diverse collection of data sets using various performance criteria. Finally, we analyze the experimental results using non-parametric statistical tests and provide recommendations for practitioners. We demonstrate that popular initialization methods often perform poorly and that there are in fact strong alternatives to these methods.
01 Jan 2013
TL;DR: A novel and fast multiscale feature detection and description approach that exploits the benefits of nonlinear scale spaces and introduces a Modified-Local Difference Binary (M-LDB) descriptor that is highly efficient, exploits gradient information from the non linear scale space, is scale and rotation invariant and has low storage requirements.
Abstract: We propose a novel and fast multiscale feature detection and description approach that exploits the benefits of nonlinear scale spaces. Previous attempts to detect and describe features in nonlinear scale spaces such as KAZE [1] and BFSIFT [6] are highly time consuming due to the computational burden of creating the nonlinear scale space. In this paper we propose to use recent numerical schemes called Fast Explicit Diffusion (FED) [3, 4] embedded in a pyramidal framework to dramatically speed-up feature detection in nonlinear scale spaces. In addition, we introduce a Modified-Local Difference Binary (M-LDB) descriptor that is highly efficient, exploits gradient information from the nonlinear scale space, is scale and rotation invariant and has low storage requirements. Our features are called Accelerated-KAZE (A-KAZE) due to the dramatic speed-up introduced by FED schemes embedded in a pyramidal framework.
TL;DR: Numerical results show that the proposed scheme can significantly improve the performance of the hybrid system in terms of D2D access rate and the overall network throughput.
Abstract: In cellular networks, proximity users may communicate directly without going through the base station, which is called Device-to-device (D2D) communications and it can improve spectral efficiency. However, D2D communications may generate interference to the existing cellular networks if not designed properly. In this paper, we study a resource allocation problem to maximize the overall network throughput while guaranteeing the quality-of-service (QoS) requirements for both D2D users and regular cellular users (CUs). A three-step scheme is proposed. It first performs admission control and then allocates powers for each admissible D2D pair and its potential CU partners. Next, a maximum weight bipartite matching based scheme is developed to select a suitable CU partner for each admissible D2D pair to maximize the overall network throughput. Numerical results show that the proposed scheme can significantly improve the performance of the hybrid system in terms of D2D access rate and the overall network throughput. The performance of D2D communications depends on D2D user locations, cell radius, the numbers of active CUs and D2D pairs, and the maximum power constraint for the D2D pairs.
TL;DR: Large-array three-dimensional circuitry integration of piezotronic transistors based on vertical zinc oxide nanowires as an active taxel-addressable pressure/force sensor matrix for tactile imaging and self-powered, multidimensional active sensing is reported.
Abstract: Designing, fabricating, and integrating arrays of nanodevices into a functional system are the key to transferring nanoscale science into applicable nanotechnology. We report large-array three-dimensional (3D) circuitry integration of piezotronic transistors based on vertical zinc oxide nanowires as an active taxel-addressable pressure/force sensor matrix for tactile imaging. Using the piezoelectric polarization charges created at a metal-semiconductor interface under strain to gate/modulate the transport process of local charge carriers, we designed independently addressable two-terminal transistor arrays, which convert mechanical stimuli applied to the devices into local electronic controlling signals. The device matrix can achieve shape-adaptive high-resolution tactile imaging and self-powered, multidimensional active sensing. The 3D piezotronic transistor array may have applications in human-electronics interfacing, smart skin, and micro- and nanoelectromechanical systems.
TL;DR: A progress report on the use of galvanic replacement for generating complex hollow nanostructures with tunable and well-controlled properties and its capability to fabricate nanomaterials with complex structures and/or compositions by coupling with other processes such as co-reduction and the Kirkendall effect.
Abstract: This article provides a progress report on the use of galvanic replacement for generating complex hollow nanostructures with tunable and well-controlled properties. We begin with a brief account of the mechanistic understanding of galvanic replacement, specifically focused on its ability to engineer the properties of metal nanostructures in terms of size, composition, structure, shape, and morphology. We then discuss a number of important concepts involved in galvanic replacement, including the facet selectivity involved in the dissolution and deposition of metals, the impacts of alloying and dealloying on the structure and morphology of the final products, and methods for promoting or preventing a galvanic replacement reaction. We also illustrate how the capability of galvanic replacement can be enhanced to fabricate nanomaterials with complex structures and/or compositions by coupling with other processes such as co-reduction and the Kirkendall effect. Finally, we highlight the use of such novel metal nanostructures fabricated via galvanic replacement for applications ranging from catalysis to plasmonics and biomedical research, and conclude with remarks on prospective future directions.
TL;DR: These two neutrino-induced events could be a first indication of an astrophysical neutrinos flux; the moderate significance, however, does not permit a definitive conclusion at this time.
Abstract: We report on the observation of two neutrino-induced events which have an estimated deposited energy in the IceCube detector of 1.04 +/- 0.16 and 1.14 +/- 0.17 PeV, respectively, the highest neutrino energies observed so far. These events are consistent with fully contained particle showers induced by neutral-current nu(e,mu,tau) ((nu) over bar (e,mu,tau)) or charged-current nu(e) ((nu) over bar (e)) interactions within the IceCube detector. The events were discovered in a search for ultrahigh energy neutrinos using data corresponding to 615.9 days effective live time. The expected number of atmospheric background is 0.082 +/- 0.004(stat)(-0.057)(+0.041)(syst). The probability of observing two or more candidate events under the atmospheric background-only hypothesis is 2.9 x 10(-3) (2.8 sigma) taking into account the uncertainty on the expected number of background events. These two events could be a first indication of an astrophysical neutrino flux; the moderate significance, however, does not permit a definitive conclusion at this time.
TL;DR: The Cherenkov Telescope Array (CTA) as discussed by the authors is a very high-energy (VHE) gamma ray observatory with an international collaboration with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America.
TL;DR: The developed automated safety checking platform informs construction engineers and managers by reporting, why, where, when, and what safety measures are needed for preventing fall-related accidents before construction starts, the safety area reviewed is fall protection.
TL;DR: A harmonic-resonator-based triboelectric nanogenerator (TENG) is presented as a sustainable power source and an active vibration sensor that greatly expands the applicability of TENGs.
Abstract: A harmonic-resonator-based triboelectric nanogenerator (TENG) is presented as a sustainable power source and an active vibration sensor. It can effectively respond to vibration frequencies ranging from 2 to 200 Hz with a considerably wide working bandwidth of 13.4 Hz. This work not only presents a new principle in the field of vibration energy harvesting but also greatly expands the applicability of TENGs.
18 Aug 2013
TL;DR: Dynodroid views an app as an event-driven program that interacts with its environment by means of a sequence of events through the Android framework, and monitors the reaction of an app upon each event in a lightweight manner, using it to guide the generation of the next event to the app.
Abstract: We present a system Dynodroid for generating relevant inputs to unmodified Android apps. Dynodroid views an app as an event-driven program that interacts with its environment by means of a sequence of events through the Android framework. By instrumenting the framework once and for all, Dynodroid monitors the reaction of an app upon each event in a lightweight manner, using it to guide the generation of the next event to the app. Dynodroid also allows interleaving events from machines, which are better at generating a large number of simple inputs, with events from humans, who are better at providing intelligent inputs. We evaluated Dynodroid on 50 open-source Android apps, and compared it with two prevalent approaches: users manually exercising apps, and Monkey, a popular fuzzing tool. Dynodroid, humans, and Monkey covered 55%, 60%, and 53%, respectively, of each app's Java source code on average. Monkey took 20X more events on average than Dynodroid. Dynodroid also found 9 bugs in 7 of the 50 apps, and 6 bugs in 5 of the top 1,000 free apps on Google Play.
TL;DR: It is demonstrated that CRISPR/Cas9 systems targeting the human hemoglobin β and C-C chemokine receptor type 5 genes have substantial off-target cleavage, especially within the hemoglobin δ and C of 2 genes, respectively, causing gross chromosomal deletions.
Abstract: The ability to precisely modify endogenous genes can significantly facilitate biological studies and disease treatment, and the clustered regularly interspaced short palindromic repeats (CRISPR) systems have the potential to be powerful tools for genome engineering. However, the target specificity of CRISPR systems is largely unknown. Here we demonstrate that CRISPR/Cas9 systems targeting the human hemoglobin β and C-C chemokine receptor type 5 genes have substantial off-target cleavage, especially within the hemoglobin δ and C-C chemokine receptor type 2 genes, respectively, causing gross chromosomal deletions. The guide strands of the CRISPR/Cas9 systems were designed to have a range of mismatches with the sequences of potential off-target sites. Off-target analysis was performed using the T7 endonuclease I mutation detection assay and Sanger sequencing. We found that the repair of the on-and off-target cleavage resulted in a wide variety of insertions, deletions and point mutations. Therefore, CRISPR/Cas9 systems need to be carefully designed to avoid potential off-target cleavage sites, including those with mismatches to the 12-bases proximal to the guide strand protospacer-adjacent motif.
TL;DR: Human skin based triboelectric nanogenerators (TENGs) that can either harvest biomechanical energy or be utilized as a self-powered tactile sensor system for touch pad technology are reported.
Abstract: We report human skin based triboelectric nanogenerators (TENG) that can either harvest biomechanical energy or be utilized as a self-powered tactile sensor system for touch pad technology. We constructed a TENG utilizing the contact/separation between an area of human skin and a polydimethylsiloxane (PDMS) film with a surface of micropyramid structures, which was attached to an ITO electrode that was grounded across a loading resistor. The fabricated TENG delivers an open-circuit voltage up to −1000 V, a short-circuit current density of 8 mA/m2, and a power density of 500 mW/m2 on a load of 100 MΩ, which can be used to directly drive tens of green light-emitting diodes. The working mechanism of the TENG is based on the charge transfer between the ITO electrode and ground via modulating the separation distance between the tribo-charged skin patch and PDMS film. Furthermore, the TENG has been used in designing an independently addressed matrix for tracking the location and pressure of human touch. The fabri...
TL;DR: An array of piezoelectric nanowire LEDs with a pixel density of 6,350 dpi is capable of mapping two-dimensional pressure distributions with a spatial resolution of 2.7 micrometres as mentioned in this paper.
Abstract: An array of piezoelectric nanowire LEDs with a pixel density of 6,350 dpi is capable of mapping two-dimensional pressure distributions with a spatial resolution of 2.7 micrometres. Pressure alters the light emissions from the LEDs, which are then imaged. Possible applications include artificial skin, robotics and touchpads.