57 research outputs found

    The Spatial Clustering of ROSAT All-Sky Survey AGN: I. The cross-correlation function with SDSS Luminous Red Galaxies

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    We investigate the clustering properties of ~1550 broad-line active galactic nuclei (AGNs) at =0.25 detected in the ROSAT All-Sky Survey (RASS) through their measured cross-correlation function with ~46,000 Luminous Red Galaxies (LRGs) in the Sloan Digital Sky Survey. By measuring the cross-correlation of our AGN sample with a larger tracer set of LRGs, we both minimize shot noise errors due to the relatively small AGN sample size and avoid systematic errors due to the spatially varying Galactic absorption that would affect direct measurements of the auto-correlation function (ACF) of the AGN sample. The measured ACF correlation length for the total RASS-AGN sample (=1.5 x 10^(44) erg/s) is r_0=4.3^{+0.4}_{-0.5} h^(-1) Mpc and the slope \gamma=1.7^{+0.1}_{-0.1}. Splitting the sample into low and high L_X samples at L_(0.5-10 keV)=10^(44) erg/s, we detect an X-ray luminosity dependence of the clustering amplitude at the ~2.5 \sigma level. The low L_X sample has r_0=3.3^{+0.6}_{-0.8} h^(-1) Mpc (\gamma=1.7^{+0.4}_{-0.3}), which is similar to the correlation length of blue star-forming galaxies at low redshift. The high L_X sample has r_0=5.4^{+0.7}_{-1.0} h^(-1) Mpc (\gamma=1.9^{+0.2}_{-0.2}), which is consistent with the clustering of red galaxies. From the observed clustering amplitude, we infer that the typical dark matter halo (DMH) mass harboring RASS-AGN with broad optical emission lines is log (M_DMH/(h^(-1) M_SUN)) =12.6^{+0.2}_{-0.3}, 11.8^{+0.6}_{-\infty}, 13.1^{+0.2}_{-0.4} for the total, low L_X, and high L_X RASS-AGN samples, respectively.Comment: The Astrophysical Journal, 713, 558 (2010), 16 pages, 11 figures, 4 table

    A Randomized and Controlled Crossover Study Investigating the Improvement of Walking and Posture Functions in Chronic Stroke Patients Using HAL Exoskeleton – The HALESTRO Study (HAL-Exoskeleton STROke Study)

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    Background: The exoskeleton HAL (hybrid assistive limb) has proven to improve walking functions in spinal cord injury and chronic stroke patients when using it for body-weight supported treadmill training (BWSTT). Compared with other robotic devices, it offers the possibility to initiate movements actively. Previous studies on stroke patients did not compare HAL-BWSTT with conventional physiotherapy (CPT). Therefore, we performed a crossover clinical trial comparing CPT and HAL-BWSTT in chronic stroke patients with hemiparesis, the HALESTRO study. Our hypothesis was that HAL-training would have greater effects on walking and posture functions compared to a mixed-approach CPT.Methods: A total of 18 chronic stroke patients participated in this study. Treatment consisted of 30 CPT sessions and of 30 sessions of BWSTT with a double leg type HAL exoskeleton successively in a randomized, crossover study design. Primary outcome parameters were walking time and speed in 10-meter walk test (10MWT), time in timed-up-and-go test (TUG) and distance in 6-min walk test (6MWT). Secondary outcome parameters were the functional ambulatory categories (FAC) and the Berg-Balance Scale (BBS). Data were assessed at baseline, at crossover and at the end of the study, all without using and wearing HAL.Results: Our study demonstrate neither a significant difference in walking parameters nor in functional and balance parameters. When HAL-BWSTT was applied to naĂŻve patients, it led to an improvement in walking parameters and in balance abilities. Pooling all data, we could show a significant effect in 10MWT, 6MWT, FAC and BBS, both therapies sequentially applied over 12 weeks. Thereby, FAC improve from dependent to independent category (3 to 4). One patient dropped out of the study due to intensive fatigue after each training session.Conclusion: HAL-BWSTT and mixed-approach CPT were effective therapies in chronic stroke patients. However, compared with CPT, HAL training with 30 sessions over 6 weeks was not more effective. The combination of both therapies led to an improvement of walking and balance functions. Robotic rehabilitation of walking disorders alone still lacks the proof of superiority in chronic stroke. Robotic treatment therapies and classical CPT rehabilitation concepts should be applied in an individualized therapy program

    Spin crossover in Fe(triazole)–Pt nanoparticle self-assembly structured at the sub-5 nm scale

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    A main goal of molecular electronics is to relate the performance of devices to the structure and electronic state of molecules. Among the variety of possibilities that organic, organometallic and coordination chemistries offer to tune the energy levels of molecular components, spin crossover phenomenon is a perfect candidate for elaboration of molecular switches. The reorganization of the electronic state population of the molecules associated to the spin crossover can indeed lead to a significant change in conductivity. However, molecular spin crossover is very sensitive to the environment and can disappear once the molecules are integrated into devices. Here, we show that the association of ultra-small 1.2 nm platinum nanoparticles with FeII triazole-based spin crossover coordination polymers leads to self-assemblies, extremely well organized at the sub-3 nm scale. The quasi-perfect alignment of nanoparticles observed by transmission electron microscopy, in addition to specific signature in infrared spectroscopy, demonstrates the coordination of the long-chain molecules with the nanoparticles. Spin crossover is confirmed in such assemblies by X-ray absorption spectroscopic measurements and shows unambiguous characteristics both in magnetic and charge transport measurements. Coordinating polymers are therefore ideal candidates for the elaboration of robust, well-organized, hybrid self-assemblies with metallic nanoparticles, while maintaining sensitive functional properties, such as spin crossover

    Peri-operative red blood cell transfusion in neonates and infants: NEonate and Children audiT of Anaesthesia pRactice IN Europe: A prospective European multicentre observational study

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    BACKGROUND: Little is known about current clinical practice concerning peri-operative red blood cell transfusion in neonates and small infants. Guidelines suggest transfusions based on haemoglobin thresholds ranging from 8.5 to 12 g dl-1, distinguishing between children from birth to day 7 (week 1), from day 8 to day 14 (week 2) or from day 15 (≄week 3) onwards. OBJECTIVE: To observe peri-operative red blood cell transfusion practice according to guidelines in relation to patient outcome. DESIGN: A multicentre observational study. SETTING: The NEonate-Children sTudy of Anaesthesia pRactice IN Europe (NECTARINE) trial recruited patients up to 60 weeks' postmenstrual age undergoing anaesthesia for surgical or diagnostic procedures from 165 centres in 31 European countries between March 2016 and January 2017. PATIENTS: The data included 5609 patients undergoing 6542 procedures. Inclusion criteria was a peri-operative red blood cell transfusion. MAIN OUTCOME MEASURES: The primary endpoint was the haemoglobin level triggering a transfusion for neonates in week 1, week 2 and week 3. Secondary endpoints were transfusion volumes, 'delta haemoglobin' (preprocedure - transfusion-triggering) and 30-day and 90-day morbidity and mortality. RESULTS: Peri-operative red blood cell transfusions were recorded during 447 procedures (6.9%). The median haemoglobin levels triggering a transfusion were 9.6 [IQR 8.7 to 10.9] g dl-1 for neonates in week 1, 9.6 [7.7 to 10.4] g dl-1 in week 2 and 8.0 [7.3 to 9.0] g dl-1 in week 3. The median transfusion volume was 17.1 [11.1 to 26.4] ml kg-1 with a median delta haemoglobin of 1.8 [0.0 to 3.6] g dl-1. Thirty-day morbidity was 47.8% with an overall mortality of 11.3%. CONCLUSIONS: Results indicate lower transfusion-triggering haemoglobin thresholds in clinical practice than suggested by current guidelines. The high morbidity and mortality of this NECTARINE sub-cohort calls for investigative action and evidence-based guidelines addressing peri-operative red blood cell transfusions strategies. TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT02350348

    EVALITA Evaluation of NLP and Speech Tools for Italian - December 17th, 2020

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    Welcome to EVALITA 2020! EVALITA is the evaluation campaign of Natural Language Processing and Speech Tools for Italian. EVALITA is an initiative of the Italian Association for Computational Linguistics (AILC, http://www.ai-lc.it) and it is endorsed by the Italian Association for Artificial Intelligence (AIxIA, http://www.aixia.it) and the Italian Association for Speech Sciences (AISV, http://www.aisv.it)

    A Putative Non-Canonical Ras-Like GTPase from P. falciparum: Chemical Properties and Characterization of the Protein.

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    During its development the malaria parasite P. falciparum has to adapt to various different environmental contexts. Key cellular mechanisms involving G-protein coupled signal transduction chains are assumed to act at these interfaces. Heterotrimeric G-proteins are absent in Plasmodium. We here describe the first cloning and expression of a putative, non-canonical Ras-like G protein (acronym PfG) from Plasmodium. PfG reveals an open reading frame of 2736 bp encoding a protein of 912 amino acids with a theoretical pI of 8.68 and a molecular weight of 108.57 kDa. Transcript levels and expression are significantly increased in the erythrocytic phase in particular during schizont and gametocyte formation. Most notably, PfG has GTP binding capacity and GTPase activity due to an EngA2 domain present in small Ras-like GTPases in a variety of Bacillus species and Mycobacteria. By contrast, plasmodial PfG is divergent from any human alpha-subunit. PfG was expressed in E. coli as a histidine-tagged fusion protein and was stable only for 3.5 hours. Purification was only possible under native conditions by Nickel-chelate chromatography and subsequent separation by Blue Native PAGE. Binding of a fluorescent GTP analogue BODIPYÂź FL guanosine 5'O-(thiotriphosphate) was determined by fluorescence emission. Mastoparan stimulated GTP binding in the presence of Mg2+. GTPase activity was determined colorimetrically. Activity expressed as absolute fluorescence was 50% higher for the human paralogue than the activity of the parasitic enzyme. The PfG protein is expressed in the erythrocytic stages and binds GTP after immunoprecipitation. Immunofluorescence using specific antiserum suggests that PfG localizes to the parasite cytosol. The current data suggest that the putitative, Ras-like G-protein might be involved in a non-canonical signaling pathway in Plasmodium. Research on the function of PfG with respect to pathogenesis and antimalarial chemotherapy is currently under way
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