2,798 research outputs found

    Marc Antoine dans la série « Rome »

    Get PDF
    Les amateurs de peplum connaissent tous la sĂ©rie britannique Rome, diffusĂ©e en deux saisons successives par la bbc au dĂ©but des annĂ©es 2000. Les plus « addicts » l’ont piratĂ©e sur internet pendant sa diffusion originale. Depuis 2006-7, nous disposons de 2 dvd diffusĂ©s par hbo Entertainment en association avec la bbc. La sĂ©rie « Rome » : prĂ©sentation Voici la fiche signalĂ©tique de la sĂ©rie  :Saison 1 : 12 Ă©pisodes = ~ 600 mn : d’AlĂ©sia aux Ides de mars (52-44 av. J.-C.)Saison 2 : 10 Ă©pisodes =..

    Theoretical And Experimental Analysis Of Supercritical Carbon Dioxide Cooling

    Get PDF
    With on-going developments in the field of trans-critical carbon dioxide (R-744) vapour compression cycles, a need to effectively describe the heat transfer of supercritical carbon dioxide for application in larger diameter tube-in-tube heat exchangers was identified. This study focuses on the in-tube cooling of supercritical carbon dioxide for application in the gas cooler of a trans-critical heat pump. A literature study has revealed Nusselt number correlations specifically developed for the cooling of supercritical carbon dioxide. These correlations were proven to be accurate only for certain operating conditions and tube geometries. A shortcoming identified in the literature reviewed was a generic heat transfer correlation that can be applied over a wide range of fluid conditions for supercritical carbon dioxide cooling. The objective of this study was to compare experimental data obtained from a trans-critical heat pump test bench with different Nusselt number correlations available in literature. The experimental tube diameter used for this study (16mm), was considerably larger than the validated tube diameters used by the researchers who developed Nusselt number correlations specifically for the supercritical cooling of carbon dioxide. The experimental Reynolds number ranges were very high (350’000 \u3c Re \u3c 680’000) compared to those found in literature (Re \u3c 300’000). Experimental results showed that correlations specifically developed for supercritical carbon dioxide cooling generally over-predicts the Nusselt numbers with an average relative error of between 62% and 458% and subsequently also over-predicts the convection heat transfer coefficients. Furthermore, generic heat transfer correlations were compared to the experimental results which over-predicted the Nusselt number with an average relative error of between 20% and 45% over the entire Reynolds number range. More specifically, the correlation by Dittus & Boelter (1985) correlated with an average relative error of 9% for 350’000 \u3c Re \u3c 550’000. From the results of this study it was concluded that cooling heat transfer of supercritical carbon dioxide in larger tube diameters and at higher Reynolds numbers is more accurately predicted by the generic Dittus & Boelter (1985) and Gnielinski (1975) correlations mainly due to the absence of thermo-physical property ratios as seen in the CO2-specific correlations

    Dynamic stability of mineral-associated organic matter: enhanced stability and turnover through organic fertilization in a temperate agricultural topsoil

    Get PDF
    Soil organic matter (SOM) plays a vital role for soil quality, sustainable food production and climate change mitigation. It is common knowledge that SOM consists of different pools with varying qualities, quantities, and turnover times. However, it is still poorly understood how mineral and organic fertilization affects the formation and stabilization of mineral-associated organic matter (MAOM) and how long it can remain there. Here, we report on the long-term effects of different farming systems on the stability and turnover of the fine silt and clay-sized MAOM fraction (<6.3 ÎŒm) of a Haplic Luvisol (0–20 cm) in the DOK long-term trial (Switzerland). We compared three farming systems with contrasting fertilization (CONMIN = pure mineral, CONFYM = mineral + organic, BIODYN = pure organic) with an unfertilized control (NOFERT) between 1982 and 2017. We performed specific surface area (SSA) measurements on fractionated MAOM samples (<6.3 ÎŒm) from 1982 to 2017, before and after removal of OM, measured the 14C activity of all samples during the entire period and estimated the mean residence time (MRT) with a model taking into account ‘bomb 14C’ and radioactive decay. We found constant MAOM-C contents under organic fertilization. Results of SSA analysis indicate best conditions for MAOM-C stabilization under organic fertilization and different sorption mechanisms in MAOM between farming systems with and without organic fertilization. The modelled MRTs were significantly higher in NOFERT (238 ± 40 yrs) and CONMIN (195 ± 27 yrs), compared to CONFYM (138 ± 18 yrs) and BIODYN (140 ± 19 yrs), implying a high C turnover (i.e. more active MAOM) at high C contents under organic fertilization. Our findings show that MAOM is not the dead OM but corroborates the concept of ‘dynamic stability’. Continuous OM inputs from organic fertilizers and their rapid and constant turnover are needed to stabilize the “stable” MAOM-C fraction

    Innovation activities of firms in Germany - results of the German CIS 2012 and 2014 : background report on the surveys of the Mannheim Innovation Panel conducted in the years 2013 to 2016

    Full text link
    Innovation is regarded as a key driver of productivity and market growth and thus has a great potential for increasing wealth. Surveying innovation activities of firms is an important contribution to a better understanding of the process of innovation and how policy may intervene to maximise the social returns of private investment into innovation. Over the past three decades, research has developed a detailed methodology to collect and analyse innovation activities at the firm level. The Oslo Manual, published by OECD and Eurostat (2005) is one important outcome of these efforts. In 1993 both organisations have started a joint initiative, known as the Community Innovation Survey (CIS), to collect firm level data on innovation across countries in concord (with each other). The German contribution to this activity is the so-called Mannheim Innovation Panel (MIP), an annual survey implemented with the first CIS wave in 1993. The MIP fully applies the methodological recommendations laid down in the Oslo Manual. It is designed as a panel survey, i.e. the same gross sample of firms is surveyed each year, with a biannual refreshment of the sample. The MIP is commissioned by the German Federal Ministry of Education and Research (BMBF) and conducted by the Centre for European Economic Research (ZEW) in cooperation with the Fraunhofer Institute for Systems and Innovation Research (ISI) and the Institute for Applied Social Science (infas). This publication reports main results of the MIP surveys conducted in the years 2013, 2014, 2015 and 2016. The surveys of the years 2013 and 2015 were the German contribution to the CIS for the reference years 2012 and 2014. The purpose of this report is to present descriptive results on various innovation indicators for the German enterprise sector

    Fertilizer quality and labile soil organic matter fractions are vital for organic carbon sequestration in temperate arable soils within a long-term trial in Switzerland

    Get PDF
    Agricultural management of soils has led to severe losses of soil organic matter (SOM), accompanied by an increased release of CO2 into the atmosphere and a reduction of soil fertility. Especially under the aspect of global warming and the increasing demand for food, there is a need for sustainable management options increasing soil organic carbon (SOC) storage in agricultural soils, but knowledge gaps exist regarding C persistence in, and its transfer between functional SOC pools, within different farming systems. Here we report on impacts of different farming systems on the temporal dynamics of SOM fractions within the DOK long-term trial (Switzerland), from 1982 to 2017. A purely minerally (CONMIN), a minerally and organically (CONFYM), and a purely organically fertilized farming system (BIODYN) were compared with an unfertilized control (NOFERT). We separated archived soils from the Haplic Luvisol (0–20 cm depth) into particulate (POM) and mineral-associated OM (MAOM) fractions, via physical fractionation, and analyzed the chemical composition of selected fractions via solid-state 13C CPMAS-NMR spectroscopy. We demonstrate that under none of the analyzed farming systems, additional SOC was sequestered in the clay-sized MAOM fraction (<6.3 ”m) over a period of 36 years. In all fertilized systems, the amount of SOC in this pool did not change, but strongly decreased in NOFERT (-27%). Bulk SOC increased in BIODYN (+13%) and CONFYM (+5%), but decreased in CONMIN (-8%) and NOFERT (-20%). As no additional SOC accumulated in the clay-sized MAOM fraction, this implies that bulk SOC increases were solely stored within labile POM fractions. NMR spectra showed comparable POM chemical compositions between different systems. Differences in fertilizer quality (BIODYN = composted farmyard manure vs CONFYM = stacked farmyard manure + mineral fertilizer) and the omission of pesticides resulted in better conditions for POM stabilization and consequently significantly higher C contents of occluded POM (oPOM) within aggregates, in BIODYN. However, this labile fraction is at high risk of being lost within a few days, as illustrated by the strong annual oPOM-C content fluctuations depending on the timing of soil sampling after harvest. The highest post-harvest oPOM-C losses in BIODYN indicate the higher dynamics compared to CONFYM. It is anticipated that only sustainable fertilization methods with continuous application of solely organic fertilizers in the long-run can maintain SOC in the labile POM fractions at elevated levels, thereby ensuring soil fertility. It also illustrates the need for prevention of major losses by careful management of the labile POM fractions, as this OM could associate with fine mineral particles at a later stage and thus contribute to OC sequestration in the stable SOC pool. Overall, the potential of arable soils to accumulate stable OC for long-term sequestration is questioned

    Detection of metastable electronic states by Penning trap mass spectrometry

    Full text link
    State-of-the-art optical clocks achieve fractional precisions of 10−1810^{-18} and below using ensembles of atoms in optical lattices or individual ions in radio-frequency traps. Promising candidates for novel clocks are highly charged ions (HCIs) and nuclear transitions, which are largely insensitive to external perturbations and reach wavelengths beyond the optical range, now becoming accessible to frequency combs. However, insufficiently accurate atomic structure calculations still hinder the identification of suitable transitions in HCIs. Here, we report on the discovery of a long-lived metastable electronic state in a HCI by measuring the mass difference of the ground and the excited state in Re, the first non-destructive, direct determination of an electronic excitation energy. This result agrees with our advanced calculations, and we confirmed them with an Os ion with the same electronic configuration. We used the high-precision Penning-trap mass spectrometer PENTATRAP, unique in its synchronous use of five individual traps for simultaneous mass measurements. The cyclotron frequency ratio RR of the ion in the ground state to the metastable state could be determined to a precision of ÎŽR=1⋅10−11\delta R=1\cdot 10^{-11}, unprecedented in the heavy atom regime. With a lifetime of about 130 days, the potential soft x-ray frequency reference at Îœ=4.86⋅1016 Hz\nu=4.86\cdot 10^{16}\,\text{Hz} has a linewidth of only ΔΜ≈5⋅10−8 Hz\Delta \nu\approx 5\cdot 10^{-8}\,\text{Hz}, and one of the highest electronic quality factor (Q=ΜΔΜ≈1024Q=\frac{\nu}{\Delta \nu}\approx 10^{24}) ever seen in an experiment. Our low uncertainty enables searching for more HCI soft x-ray clock transitions, needed for promising precision studies of fundamental physics in a thus far unexplored frontier

    Biological soil quality and soil organic carbon change in biodynamic, organic, and conventional farming systems after 42 years

    Get PDF
    Soils are the basis of life on land and the ways in which we manage them for crop production, impact their role, functions and quality. Conventional farming uses industrial inputs to a level that is economically justified, whilst organic farming systems avoid mineral fertilizers and synthetic chemical pesticides. This study investigates the long-term effect of organic and conventional farming systems on soil quality. The DOK trial (bioDynamic, bioOrganic, Konventionell (German for conventional)) running since 1978 in Therwil (CH), compares bioorganic (BIOORG), biodynamic (BIODYN), and conventional (CONFYM) farming systems at two farmyard manure intensities corresponding to 0.7 and 1.4 livestock units per hectare with a purely mineral fertilized system (CONMIN) and an unfertilized control (NOFERT). The treatments in the DOK trial vary in plant protection and receive system-specific organic matter inputs differing in rate and quality. With this work, we revisit the soil organic carbon (SOC) dynamics across 42 years and redefine the previous perception of mainly declining SOC contents after 21 years of organic and conventional management (Fliessbach et al. 2007). After 42 years, we found SOC contents to be increased in BIODYN 1.4 and to a lesser extent also in BIOORG 1.4. CONFYM 1.4 showed stable SOC contents, while systems fertilized with manure of 0.7 livestock units and CONMIN lost SOC. SOC loss was highest in NOFERT. Enhanced biological soil quality under organic and particularly biodynamic management highlights the close link between soil biology and SOC changes. The impact of farming systems on SOC was detectable after 2 decades of continuous management. We conclude that recycling manure at a level of 1.4 livestock units per hectare permits maintenance of SOC levels and that composting manure, as performed in BIODYN 1.4, helps to further increase SOC levels and improve biological soil quality

    Determinants of pain interference and headache impact in patients who have chronic migraine with medication overuse: Results from the MOTS trial

    Get PDF
    OBJECTIVE: Pain interference and headache impact refer to negative consequences that pain and headache have on one\u27s life. This study investigated determinants of these negative impacts in a large patient cohort who have chronic migraine with medication overuse. METHODS: Six hundred and eleven adults were enrolled from 34 headache, neurology, and primary care clinics. Negative consequences of chronic migraine with medication overuse were determined using the Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference 6b questionnaire and the Headache Impact Test 6. Relationships between PROMIS-6b and Headache Impact Test 6 scores with demographics, headache characteristics, medication use, anxiety symptoms, and depression symptoms were assessed with linear regression. Elastic Net regression was used to develop a multiple regression model. RESULTS: PROMIS-6b T-Scores averaged 65.2 (SD 5.4) and Headache Impact Test 6 scores averaged 65.0 (SD 5.3), indicating severe negative consequences of chronic migraine with medication overuse. Chronic migraine with medication overuse interfered with enjoyment of life, concentration, daily activities, doing tasks away from home, and socializing. Depression symptom severity had the strongest relationship with pain interference and headache impact. Moderate-to-severe headache frequency, headache intensity, and anxiety symptoms were also associated with pain interference and headache impact. CONCLUSIONS: Chronic migraine with medication overuse is associated with substantial negative consequences, the extent of which is most strongly related to depression symptoms

    MOG-IgG in NMO and related disorders: a multicenter study of 50 patients. Part 3: Brainstem involvement - frequency, presentation and outcome

    Get PDF
    Background Myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) are present in a subset of aquaporin-4 (AQP4)-IgG-negative patients with optic neuritis (ON) and/or myelitis. Little is known so far about brainstem involvement in MOG-IgG-positive patients. Objective To investigate the frequency, clinical and paraclinical features, course, outcome, and prognostic implications of brainstem involvement in MOG-IgG-positive ON and/or myelitis. Methods Retrospective case study. Results Among 50 patients with MOG-IgG-positive ON and/or myelitis, 15 (30 %) with a history of brainstem encephalitis were identified. All were negative for AQP4-IgG. Symptoms included respiratory insufficiency, intractable nausea and vomiting (INV), dysarthria, dysphagia, impaired cough reflex, oculomotor nerve palsy and diplopia, nystagmus, internuclear ophthalmoplegia (INO), facial nerve paresis, trigeminal hypesthesia/dysesthesia, vertigo, hearing loss, balance difficulties, and gait and limb ataxia; brainstem involvement was asymptomatic in three cases. Brainstem inflammation was already present at or very shortly after disease onset in 7/15 (47 %) patients. 16/21 (76.2 %) brainstem attacks were accompanied by acute myelitis and/or ON. Lesions were located in the pons (11/13), medulla oblongata (8/14), mesencephalon (cerebral peduncles; 2/14), and cerebellar peduncles (5/14), were adjacent to the fourth ventricle in 2/12, and periaqueductal in 1/12; some had concomitant diencephalic (2/13) or cerebellar lesions (1/14). MRI or laboratory signs of blood-brain barrier damage were present in 5/12. Cerebrospinal fluid pleocytosis was found in 11/14 cases, with neutrophils in 7/11 (3-34 % of all CSF white blood cells), and oligoclonal bands in 4/14. Attacks were preceded by acute infection or vaccination in 5/15 (33.3 %). A history of teratoma was noted in one case. The disease followed a relapsing course in 13/15 (87 %); the brainstem was involved more than once in 6. Immunosuppression was not always effective in preventing relapses. Interferon-beta was followed by new attacks in two patients. While one patient died from central hypoventilation, partial or complete recovery was achieved in the remainder following treatment with high-dose steroids and/or plasma exchange. Brainstem involvement was associated with a more aggressive general disease course (higher relapse rate, more myelitis attacks, more frequently supratentorial brain lesions, worse EDSS at last follow-up). Conclusions Brainstem involvement is present in around one third of MOG-IgG-positive patients with ON and/or myelitis. Clinical manifestations are diverse and may include symptoms typically seen in AQP4-IgG-positive neuromyelitis optica, such as INV and respiratory insufficiency, or in multiple sclerosis, such as INO. As MOG-IgG-positive brainstem encephalitis may take a serious or even fatal course, particular attention should be paid to signs or symptoms of additional brainstem involvement in patients presenting with MOG-IgG-positive ON and/or myelitis

    Apheresis therapies for NMOSD attacks A retrospective study of 207 therapeutic interventions

    Get PDF
    Objective To analyze whether 1 of the 2 apheresis techniques, therapeutic plasma exchange (PE) or immunoadsorption (IA), is superior in treating neuromyelitis optica spectrum disorder (NMOSD) attacks and to identify predictive factors for complete remission (CR). Methods This retrospective cohort study was based on the registry of the German Neuromyelitis Optica Study Group, a nationwide network established in 2008. It recruited patients with neuromyelitis optica diagnosed according to the 2006 Wingerchuk criteria or with aquaporin-4 (AQP4-ab)-antibody-seropositive NMOSD treated at 6 regional hospitals and 16 tertiary referral centers until March 2013. Besides descriptive data analysis of patient and attack characteristics, generalized estimation equation (GEE) analyses were applied to compare the effectiveness of the 2 apheresis techniques. A GEE model was generated to assess predictors of outcome. Results Two hundred and seven attacks in 105 patients (87% AQP4-ab-antibody seropositive) were treated with at least 1 apheresis therapy. Neither PE nor IA was proven superior in the therapy of NMOSD attacks. CR was only achieved with early apheresis therapy. Strong predictors for CR were the use of apheresis therapy as first-line therapy (OR 12.27, 95% CI: 1.04-144.91, p = 0.047), time from onset of attack to start of therapy in days (OR 0.94, 95% CI: 0.89-0.99, p = 0.014), the presence of AQP4-abantibodies (OR 33.34, 95% CI: 1.76-631.17, p = 0.019), and monofocal attack manifestation (OR 4.71, 95% CI: 1.03-21.62, p = 0.046). Conclusion: s Our findings suggest early use of an apheresis therapy in NMOSD attacks, particularly in AQP4-ab-seropositive patients. No superiority was shown for one of the 2 apheresis techniques
    • 

    corecore