3,192 research outputs found

    A high-performance data structure for mobile information systems

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    Mobile information systems can now be provided on small form-factor computers. Dictionary-based data compression extends the capabilities of systems with limited processing and memory to enable data intensive applications to be supported in such environments. The nature of judicial sentencing decisions requires that a support system provides accurate and up-to-date data and is compatible with the professional working experience of a judge. The difficulties caused by mobility and the data dependence of the decision-making process are addressed by an Internet-based architecture for collecting and distributing system data.We describe an approach to dictionary-based data compression and the structure of an information system that makes use of this technology

    Importance of Baryon-Baryon Coupling in Hypernuclei

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    The ΛN−ΣN\Lambda N - \Sigma N coupling in Λ\Lambda--hypernuclei and ΛΛ−ΞN\Lambda \Lambda - \Xi N coupling in ΛΛ\Lambda \Lambda--hypernuclei produce novel physics not observed in the conventional, nonstrange sector. Effects of Λ↔Σ\Lambda \leftrightarrow \Sigma conversion in Λ3^3_{\Lambda}H are reviewed. The role of ΛN−ΣN\Lambda N - \Sigma N coupling suppression in the A=4,5A=4,5 Λ\Lambda--hypernuclei due to Pauli blocking is highlighted, and the implications for the structure of    Λ10^{10}_{\;\, \Lambda}B are explored. Suppression of ΛΛ−ΞN\Lambda \Lambda - \Xi N conversion in ΛΛ     6^{\;\;\, 6}_{\Lambda \Lambda}He is hypothesized as the reason that the matrix element is small. Measurement of ΛΛ     4^{\;\;\, 4}_{\Lambda \Lambda}H is proposed to investigate the full ΛΛ−ΞN\Lambda \Lambda - \Xi N interaction. The implication for ΛΛ\Lambda \Lambda analog states is discussed.Comment: 17 pages LATEX, 1 figure uuencoded postscrip

    Reactive Quenching Of Od A (2)ÎŁ(+) By H-2: Translational Energy Distributions For H- And D-Atom Product Channels

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    The H- and D-atom products from collisional quenching of OD A (2)Sigma(+) by H-2 are characterized through Doppler spectroscopy using two-photon (2 S-2 \u3c-\u3c- 1 S-2) laser-induced fluorescence. Partial deuteration enables separation of the channel forming H + HOD products, which accounts for 75% of reactive quenching events, from the D + H2O product channel. The Doppler profiles, along with those reported previously for other isotopic variants, are transformed into product translational energy distributions using a robust fitting procedure based on discrete velocity basis functions. The product translational energy distribution for the H- atom channel is strongly peaked at low energy (below 0.5 eV) with a long tail extending to the energetic limit. By contrast, the D-atom channel exhibits a small peak at low translational energy with a distinctive secondary peak at higher translational energy (approximately 1.8 eV) before falling off to higher energy. In both cases, most of the available energy flows into internal excitation of the water products. Similar distributions are obtained upon reanalysis of D- and H- atom Doppler profiles, respectively, from reactive quenching of OH A (2)Sigma(+) by D-2. The sum of the translational energy distributions for H- and D- atom channels is remarkably similar to that obtained for OH A (2)Sigma(+) + H-2, where the two channels cannot be distinguished from one another. The product translational energy distributions from reactive quenching are compared with those obtained from a previous experiment performed at higher collision energy, quasiclassical trajectory calculations of the post-quenching dynamics, and a statistical model. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3644763

    Edge theories in Projected Entangled Pair State models

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    We study the edge physics of gapped quantum systems in the framework of Projected Entangled Pair State (PEPS) models. We show that the effective low-energy model for any region acts on the entanglement degrees of freedom at the boundary, corresponding to physical excitations located at the edge. This allows us to determine the edge Hamiltonian in the vicinity of PEPS models, and we demonstrate that by choosing the appropriate bulk perturbation, the edge Hamiltonian can exhibit a rich phase diagram and phase transitions. While for models in the trivial phase any Hamiltonian can be realized at the edge, we show that for topological models, the edge Hamiltonian is constrained by the topological order in the bulk which can e.g. protect a ferromagnetic Ising chain at the edge against spontaneous symmetry breaking.Comment: 5 pages, 4 figure

    Funkcija x→ │x│

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    U predavanju se navodi nekoliko ilustrativnih primjera u kojima se koriste svojstva funkcije x→ │x│

    The Case for Learned Index Structures

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    Indexes are models: a B-Tree-Index can be seen as a model to map a key to the position of a record within a sorted array, a Hash-Index as a model to map a key to a position of a record within an unsorted array, and a BitMap-Index as a model to indicate if a data record exists or not. In this exploratory research paper, we start from this premise and posit that all existing index structures can be replaced with other types of models, including deep-learning models, which we term learned indexes. The key idea is that a model can learn the sort order or structure of lookup keys and use this signal to effectively predict the position or existence of records. We theoretically analyze under which conditions learned indexes outperform traditional index structures and describe the main challenges in designing learned index structures. Our initial results show, that by using neural nets we are able to outperform cache-optimized B-Trees by up to 70% in speed while saving an order-of-magnitude in memory over several real-world data sets. More importantly though, we believe that the idea of replacing core components of a data management system through learned models has far reaching implications for future systems designs and that this work just provides a glimpse of what might be possible

    Revealing and Resolving the Restrained Enzymatic Cleavage of DNA Self-Assembled Monolayers on Gold: Electrochemical Quantitation and ESI-MS Confirmation

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    Herein we report a combined electrochemical and ESI-MS study of the enzymatic hydrolysis efficiency of DNA self-assembled monolayers (SAMs) on gold, platform systems for understanding nucleic acid surface chemistry and for constructing DNA-based biosensors. Our electrochemical approach is based on the comparison of the amounts of surface-tethered DNA nucleotides before and after Exonuclease I (Exo I) incubation using electrostatically bound [Ru(NH3)6]3+ as redox indicators. It is surprising to reveal that the hydrolysis efficiency of ssDNA SAMs does not depend on the packing density and base sequence, and that the cleavage ends with surface-bound shorter strands (9-13 mers). The ex-situ ESI-MS observations confirmed that the hydrolysis products for ssDNA SAMs (from 24 to 56 mers) are dominated with 10-15 mer fragments, in contrast to the complete digestion in solution. Such surface-restrained hydrolysis behavior is due to the steric hindrance of the underneath electrode to the Exo I/DNA binding, which is essential for the occurrence of Exo I-catalyzed processive cleavage. More importantly, we have shown that the hydrolysis efficiency of ssDNA SAMs can be remarkably improved by adopting long alkyl linkers (locating DNA strands further away from the substrates)

    Endoscopic Unroofing of a Choledochocele

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    A 42-year-old man with previous laparoscopic cholecystectomy was referred for further evaluation of recurrent acute pancreatitis. Secretin-enhanced magnetic resonance cholangiopancreatography showed a 16 mm × 11 mm T2 hyperintense cystic lesion at the major papilla (Figure 1). Upper endoscopic ultrasound (EUS) showed a 15 mm × 10 mm oval, intramural, subepithelial lesion at the major papilla (Figure 2). Endoscopic retrograde cholangiopancreatography (ERCP) showed an 18-mm bulging lesion at the major papilla with normal overlying mucosa (Figure 3); injected contrast collected into a 16-mm cystic cavity (Figure 4). Findings were suggestive of type A choledochocele. A 10–12-mm freehand precut papillotomy was made with a monofilament needle-knife (Huibregtse Single-Lumen Needle Knife, Cook Medical, Bloomington, IN) using an ERBE VIO electrocautery system (ERBE USA; Marietta, GA). The incision was made as long as safely possible in an attempt to open the choledochocele completely and thus expose its walls and contents. We used a standard pull sphincterotome and ERBE electrocautery to perform the pancreatic sphincterotomy, followed by placement of a pancreatic stent. Biliary sphincterotomy was performed using the same technique (settings for needle-knife and pull sphincterotomies: Endocut I, blend current, effect 2/duration 2/interval 3). Biopsies of the inverted choledochocele showed biliary mucosa and duodenal columnar epithelium with inflammation and fibrosis, and no dysplasia. Follow-up ERCP at 4 weeks showed adequate unroofing of the choledochocele (Figure 5); the pancreatic stent was subsequently removed. The patient reported no recurrence of acute pancreatitis at 6-, 12-, and 18-month follow-up intervals
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