How Many and What Types of SPARQL Queries can be Answered through Zero-Knowledge Link Traversal?

The current de-facto way to query the Web of Data is through the SPARQL protocol, where a client sends queries to a server through a SPARQL endpoint. Contrary to an HTTP server, providing and maintaining a robust and reliable endpoint requires a significant effort that not all publishers are willing or able to make. An alternative query evaluation method is through link traversal, where a query is answered by dereferencing online web resources (URIs) at real time. While several approaches for such a lookup-based query evaluation method have been proposed, there exists no analysis of the types (patterns) of queries that can be directly answered on the live Web, without accessing local or remote endpoints and without a-priori knowledge of available data sources. In this paper, we first provide a method for checking if a SPARQL query (to be evaluated on a SPARQL endpoint) can be answered through zero-knowledge link traversal (without accessing the endpoint), and analyse a large corpus of real SPARQL query logs for finding the frequency and distribution of answerable and non-answerable query patterns. Subsequently, we provide an algorithm for transforming answerable queries to SPARQL-LD queries that bypass the endpoints. We report experimental results about the efficiency of the transformed queries and discuss the benefits and the limitations of this query evaluation method.Comment: Preprint of paper accepted for publication in the 34th ACM/SIGAPP Symposium On Applied Computing (SAC 2019

Epstein-Barr virus nuclear antigen 3A protein regulates CDKN2B transcription via interaction with MIZ-1

The Epstein-Barr virus (EBV) nuclear antigen 3 family of protein is critical for the EBV-induced primary B-cell growth transformation process. Using a yeast two-hybrid screen we identified 22 novel cellular partners of the EBNA3s. Most importantly, among the newly identified partners, five are known to play direct and important roles in transcriptional regulation. Of these, the Myc-interacting zinc finger protein-1 (MIZ-1) is a transcription factor initially characterized as a binding partner of MYC. MIZ-1 activates the transcription of a number of target genes including the cell cycle inhibitor CDKN2B. Focusing on the EBNA3A/MIZ-1 interaction we demonstrate that binding occurs in EBV-infected cells expressing both proteins at endogenous physiological levels and that in the presence of EBNA3A, a significant fraction of MIZ-1 translocates from the cytoplasm to the nucleus. Moreover, we show that a trimeric complex composed of a MIZ-1 recognition DNA element, MIZ-1 and EBNA3A can be formed, and that interaction of MIZ-1 with nucleophosmin (NPM), one of its coactivator, is prevented by EBNA3A. Finally, we show that, in the presence of EBNA3A, expression of the MIZ-1 target gene, CDKN2B, is downregulated and repressive H3K27 marks are established on its promoter region suggesting that EBNA3A directly counteracts the growth inhibitory action of MIZ-1

First measurement of the Non-instantaneous response Time of a χ(3) nonlinear optical effect

The third harmonic of a few-cycle pulse, generated at different dielectric surfaces, is investigated using interferometric frequency-resolved optical gating. We present direct experimental evidence for a non-instantaneous nonlinear response in a TiO2 thin film whereas surface third-harmonic generation in a SiO2 sample does not show any indication for non-instanteneity. To the best of our knowledge, this constitutes the first report of a non-instantaneous nonlinear optical response of a dielectric optical material

Multi-Sideband RABBIT in Argon

We report a joint experimental and theoretical study of a three-sideband (3-SB) modification of the "reconstruction of attosecond beating by interference of two-photon transitions" (RABBIT) setup. The 3-SB RABBIT scheme makes it possible to investigate phases resulting from interference between transitions of different orders in the continuum. Furthermore, the strength of this method is its ability to focus on the atomic phases only, independent of a chirp in the harmonics, by comparing the RABBIT phases extracted from specific SB groups formed by two adjacent harmonics. We verify earlier predictions that the phases and the corresponding time delays in the three SBs extracted from angle-integrated measurements become similar with increasing photon electron energy. A variation in the angle dependence of the RABBIT phases in the three SBs results from the distinct Wigner and continuum-continuum coupling phases associated with the individual angular momentum channels. A qualitative explanation of this dependence is attempted by invoking a propensity rule. Comparison between the experimental data and predictions from an R-matrix (close-coupling) with time dependence calculation shows qualitative agreement in the observed trends.Comment: 8 pages, 5 figure

Multi-sideband interference structures by high-order photon-induced continuum-continuum transitions in helium

Following up on a previous paper on two-color photoionization of Ar(3p) [Bharti et al., Phys. Rev. A 103 (2021) 022834], we present measurements and calculations for a modified three-sideband (3-SB) version of the "reconstruction of attosecond beating by interference of two-photon transitions" (RABBITT) configuration applied to He(1s). The 3-SB RABBITT approach allows us to explore interference effects between pathways involving different orders of transitions within the continuum. The relative differences in the retrieved oscillation phases of the three sidebands provide insights into the continuum-continuum transitions. The ground state of helium has zero orbital angular momentum, which simplifies the analysis of oscillation phases and their angle-dependence within the three sidebands. We find qualitative agreement between our experimental results and the theoretical predictions for many cases but also observe some significant quantitative discrepancies.Comment: 9 pages, 6 figure

Recent and future trends in synthetic greenhouse gas radiative forcing

Atmospheric measurements show that emissions of hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons are now the primary drivers of the positive growth in synthetic greenhouse gas (SGHG) radiative forcing. We infer recent SGHG emissions and examine the impact of future emissions scenarios, with a particular focus on proposals to reduce HFC use under the Montreal Protocol. If these proposals are implemented, overall SGHG radiative forcing could peak at around 355 mW m[superscript −2] in 2020, before declining by approximately 26% by 2050, despite continued growth of fully fluorinated greenhouse gas emissions. Compared to “no HFC policy” projections, this amounts to a reduction in radiative forcing of between 50 and 240 mW m[superscript −2] by 2050 or a cumulative emissions saving equivalent to 0.5 to 2.8 years of CO2 emissions at current levels. However, more complete reporting of global HFC emissions is required, as less than half of global emissions are currently accounted for.Natural Environment Research Council (Great Britain) (Advanced Research Fellowship NE/I021365/1)United States. National Aeronautics and Space Administration (Upper Atmospheric Research Program Grant NNX11AF17G)United States. National Oceanic and Atmospheric Administratio

Numerical evaluation of a novel double-concentric swirl burner for sulfur combustion

A burner system for the efficient and clean combustion of sulfur is introduced, which serves as a key component in a novel solar power cycle using sulfur as chemical storage medium of solar energy. In order to validate the proposed design concept, highly-resolved numerical simulations have been performed. The current setup is operated with a thermal load of 20 kW or power density of 5 MW/m$^{3}$. Two nozzle configurations with different swirl intensities (SI) of the airflow are studied. A large inner recirculation zone is observed for the nozzle with a high SI (HSI), which leads to a strong radial dispersion of the sulfur spray and a broad, short flame in the combustion chamber; although this HSI design is beneficial from the viewpoint of flame stabilization, it causes a large number of sulfur droplets hitting the chamber wall. In contrast, the nozzle design with a low SI (LSI) yields a narrow spray and a long jet flame, with much less droplets hitting the wall. The HSI nozzle shows an overall higher flame temperature compared with the LSI nozzle, which is confirmed to be caused by burning at a higher local fuel equivalence ratio. This is attributed to the strong inner recirculation flow generated by the high swirl intensity, which results in an enhanced evaporation and mixing of sulfur droplets with air. In terms of operability and NOx emission, the LSI burner is preferred due to less sulfur droplets hitting the chamber wall and the lower flame temperature

Pronounced haemodynamic changes during and after robotic-assisted laparoscopic prostatectomy: a prospective observational study

Objectives Robotic-assisted laparoscopic prostatectomy (RALP) is typically conducted in steep Trendelenburg position (STP). This study investigated the influence of permanent 45 degrees STP and capnoperitoneum on haemodynamic parameters during and after RALP. Design Prospective observational study. Setting Haemodynamic changes were recorded with transpulmonary thermodilution and pulse contour analysis in men undergoing RALP under standardised anaesthesia. Participants Informed consent was obtained from 51 patients scheduled for elective RALP in a University Medical Centre in Germany. Interventions Heart rate, mean arterial pressure, central venous pressure (CVP), Cardiac Index (CI), systemic vascular resistance (SVR), Global End-Diastolic Volume Index (GEDI), global ejection fraction (GEF), Cardiac Power Index (CPI) and stroke volume variation (SVV) were recorded at six time points: 20 min after induction of anaesthesia (T1), after insufflation of capnoperitoneum in supine position (T2), after 30 min in STP (T3), when controlling Santorini's plexus in STP (T4), before awakening in supine position (T5) and after 45 min in the recovery room (T6). Adverse cardiac events were registered intraoperatively and postoperatively. Results All haemodynamic parameters were significantly changed by capnoperitoneum and STP during RALP and partly normalised at T6. CI, GEF and CPI were highest at T6 (CI: 3.9 vs 2.2 L/min/m(2); GEF: 26 vs 22%; CPI: 0.80 vs 0.39 W/m(2); p<0.001). CVP was highest at T4 (31 vs 7 mm Hg, p<0.001) and GEDI at T6 (819 vs 724 mL/m(2), p=0.005). Mean SVR initially increased (T2) but had decreased by 24% at T6 (p<0.001). SVV was highest at T5 (12 vs 9%, p<0.001). Two of the patients developed cardiac arrhythmia during RALP and one patient suffered postoperative cardiac ischaemia. Conclusions RALP led to pronounced perioperative haemodynamic changes. The combination of increased cardiac contractility and heart rate reflects a hyperdynamic situation during and after RALP. Anaesthesiologists should be aware of unnoticed pre-existing heart failure to worsen during STP in patients undergoing RALP

Greenhouse gas measurements from a UK network of tall towers: technical description and first results

A network of three tall tower measurement stations was set up in 2012 across the United Kingdom to expand measurements made at the long-term background northern hemispheric site, Mace Head, Ireland. Reliable and precise in situ greenhouse gas (GHG) analysis systems were developed and deployed at three sites in the UK with automated instrumentation measuring a suite of GHGs. The UK Deriving Emissions linked to Climate Change (UK DECC) network uses tall (165–230 m) open-lattice telecommunications towers, which provide a convenient platform for boundary layer trace gas sampling. In this paper we describe the automated measurement system and first results from the UK DECC network for CO2, CH4, N2O, SF6, CO and H2. CO2 and CH4 are measured at all of the UK DECC sites by cavity ring-down spectroscopy (CRDS) with multiple inlet heights at two of the three tall tower sites to assess for boundary layer stratification. The short-term precisions (1σ on 1 min means) of CRDS measurements at background mole fractions for January 2012 to September 2015 is < 0.05 µmol mol−1 for CO2 and < 0.3 nmol mol−1 for CH4. Repeatability of standard injections (1σ) is < 0.03 µmol mol−1 for CO2 and < 0.3 nmol mol−1 for CH4 for the same time period. N2O and SF6 are measured at three of the sites, and CO and H2 measurements are made at two of the sites, from a single inlet height using gas chromatography (GC) with an electron capture detector (ECD), flame ionisation detector (FID) or reduction gas analyser (RGA). Repeatability of individual injections (1σ) on GC and RGA instruments between January 2012 and September 2015 for CH4, N2O, SF6, CO and H2 measurements were < 2.8 nmol mol−1, < 0.4 nmol mol−1, < 0.07 pmol mol−1, < 2 nmol mol−1 and < 3 nmol mol−1, respectively. Instrumentation in the network is fully automated and includes sensors for measuring a variety of instrumental parameters such as flow, pressures, and sampling temperatures. Automated alerts are generated and emailed to site operators when instrumental parameters are not within defined set ranges. Automated instrument shutdowns occur for critical errors such as carrier gas flow rate deviations. Results from the network give good spatial and temporal coverage of atmospheric mixing ratios within the UK since early 2012. Results also show that all measured GHGs are increasing in mole fraction over the selected reporting period and, except for SF6, exhibit a seasonal trend. CO2 and CH4 also show strong diurnal cycles, with night-time maxima and daytime minima in mole fractions

Probing host pathogen cross-talk by transcriptional profiling of both Mycobacterium tuberculosis and infected human dendritic cells and macrophages

This study provides the proof of principle that probing the host and the microbe transcriptomes simultaneously is a valuable means to accessing unique information on host pathogen interactions. Our results also underline the extraordinary plasticity of host cell and pathogen responses to infection, and provide a solid framework to further understand the complex mechanisms involved in immunity to M. tuberculosis and in mycobacterial adaptation to different intracellular environments