236 research outputs found
The protein puzzle : the consumption and production of meat, dairy and fish in the European Union
In het rapport 'The protein puzzle. The consumption and production of meat, dairy and fish in the European Union' brengen onderzoekers van het Planbureau voor de Leefomgeving (PBL) in kaart wat de gevolgen van de productie en consumptie van dierlijke eiwitten zijn voor milieu, natuur en gezondheid. Vervolgens schetst het PBL welke opties er in Europees verband zijn om de negatieve effecten te verminderen. Met deze studie verschaft het PBL relevante feiten en cijfers ten behoeve van het debat over eiwitconsumptie, inclusief een indicatie van de onzekerheden daarbij
Sprite discharges on Venus, Jupiter and Saturn: a laboratory investigation in planetary gas mixtures
Lightning was detected on several planets in the solar system, where it could also produce sprites
in the upper layers of these atmospheres. Large sprite discharges at mesospheric altitudes on Earth have been found to be physically similar to streamer discharges in air at sea level density. Based on this understanding, we investigate possible sprite discharges on the Gas Giant planets and on Venus through laboratory experiments on streamers in H2-He and CO2-N2 mixtures. Streamer diameters, velocities, radiance and overall morphology are investigated for sprites on Jupiter, Saturn and Venus, by means of a fast ICCD camera. The spectra of the streamer discharges are measured; they are dominated by the minority species N2 on Venus, and by radiative dissociative continuum radiation of H2 in the Gas Giants. The spectrum of a fully developed spark on Venus and Saturn is also measured
Extra-terrestrial sprites: laboratory investigations in planetary gas mixtures
We investigate streamers in gas mixtures representing the atmospheres of Jupiter, Saturn (H2-He) and Venus (CO2-N2). Streamer diameters, velocities, radiance and overall morphology are investigated with fast ICCD camera images. We confirm experimentally the scaling of streamer diameters in these gases by studying streamers with minimal diameters. The brightness of laboratory streamers is investigated, and a scaling model for atmospheric sprites is proposed. Fitting the scaling model with measurements, we give an estimate of minimal sprite brightness on Earth, Jupiter and Saturn. The estimated brightness of terrestrial sprites agrees well with observations and with existing models, and may serve as a benchmark for space-based observations of TLEs by planetary missions such as Cassini and Juno
Prognosis and institutionalization of frail community-dwelling older patients following a proximal femoral fracture:a multicenter retrospective cohort study
SUMMARY: Hip fractures are a serious public health issue with major consequences, especially for frail community dwellers. This study found a poor prognosis at 6 months post-trauma with regard to life expectancy and rehabilitation to pre-fracture independency levels. It should be realized that recovery to pre-trauma functioning is not a certainty for frail community-dwelling patients. INTRODUCTION: Proximal femoral fractures are a serious public health issue in the older patient. Although a significant rise in frail community-dwelling elderly is expected because of progressive aging, a clear overview of the outcomes in these patients sustaining a proximal femoral fracture is lacking. This study assessed the prognosis of frail community-dwelling patients who sustained a proximal femoral fracture. METHODS: A multicenter retrospective cohort study was performed on frail community-dwelling patients with a proximal femoral fracture who aged over 70 years. Patients were considered frail if they were classified as American Society of Anesthesiologists score ≥ 4 and/or a BMI < 18.5 kg/m(2) and/or Functional Ambulation Category ≤ 2 pre-trauma. The primary outcome was 6-month mortality. Secondary outcomes were adverse events, health care consumption, rate of institutionalization, and functional recovery. RESULTS: A total of 140 out of 2045 patients matched the inclusion criteria with a median age of 85 (P(25)–P(75) 80–89) years. The 6-month mortality was 58 out of 140 patients (41%). A total of 102 (73%) patients experienced adverse events. At 6 months post-trauma, 29 out of 120 (24%) were readmitted to the hospital. Out of the 82 surviving patients after 6 months, 41 (50%) were unable the return to their home, and only 32 (39%) were able to achieve outdoor ambulation. CONCLUSION: Frail community-dwelling older patients with a proximal femoral fracture have a high risk of death, adverse events, and institutionalization and often do not reobtain their pre-trauma level of independence. Foremost, the results can be used for realistic expectation management
Probing photo-ionization: Experiments on positive streamers in pure gasses and mixtures
Positive streamers are thought to propagate by photo-ionization whose
parameters depend on the nitrogen:oxygen ratio. Therefore we study streamers in
nitrogen with 20%, 0.2% and 0.01% oxygen and in pure nitrogen, as well as in
pure oxygen and argon. Our new experimental set-up guarantees contamination of
the pure gases to be well below 1 ppm. Streamers in oxygen are difficult to
measure as they emit considerably less light in the sensitivity range of our
fast ICCD camera than the other gasses. Streamers in pure nitrogen and in all
nitrogen/oxygen mixtures look generally similar, but become somewhat thinner
and branch more with decreasing oxygen content. In pure nitrogen the streamers
can branch so much that they resemble feathers. This feature is even more
pronounced in pure argon, with approximately 10^2 hair tips/cm^3 in the
feathers at 200 mbar; this density could be interpreted as the free electron
density creating avalanches towards the streamer stem. It is remarkable that
the streamer velocity is essentially the same for similar voltage and pressure
in all nitrogen/oxygen mixtures as well as in pure nitrogen, while the oxygen
concentration and therefore the photo-ionization lengths vary by more than five
orders of magnitude. Streamers in argon have essentially the same velocity as
well. The physical similarity of streamers at different pressures is confirmed
in all gases; the minimal diameters are smaller than in earlier measurements.Comment: 28 pages, 14 figures. Major differences with v1: - appendix and
spectra removed - subsection regarding effects of repetition frequency added
- many more smaller change
GHOST - safe-guarding home IoT environments with personalised real-time risk control
We present the European research project GHOST, (Safe-guarding home IoT environments with personalised real-time risk control), which challenges the traditional cyber security solutions for the IoT by proposing a novel reference architecture that is embedded in an adequately adapted smart home network gateway, and designed to be vendor-independent. GHOST proposes to lead a paradigm shift in consumer cyber security by coupling usable security with transparency and behavioural engineering
The importance of thermal dissociation in CO2 microwave discharges investigated by power pulsing and rotational Raman scattering
The input power of a CO2 microwave plasma is modulated at kHz rate in scans of duty cycle at constant average power to investigate gas heating dynamics and its relation to dissociation efficiency. Rotational temperature profiles obtained from rotational Raman scattering reveal peak temperatures of up to 3000 K, while the edge temperature remains cold (500 K). During the plasma \u27OFF\u27-period, the gas cools down convectively, but remains overall too hot to allow for strong overpopulation of vibrational modes (2200 K in the core). Fast optical imaging monitors plasma volume variations and shows that power density scales with peak power. As dissociation scales with observed peak rotational temperature, it is concluded that thermal processes dominate. A simple 0D model is constructed which explains how higher power density favors dissociation over radial energy transport. Thermal decomposition is reviewed in relation to quenching oxygen radicals with vibrationally excited CO2, to reflect on earlier reported record efficiencies of 90%.</p
How the alternating degeneracy in rotational Raman spectra of CO2 and C2H2 reveals the vibrational temperature
The contribution of higher vibrational levels to the rotational spectrum of linear polyatomic molecules with a center of symmetry (CO2 and C2H2) is assessed. An apparent nuclear degeneracy is analytically formulated by vibrational averaging and compared to numerical averaging over vibrational levels. It enables inferring the vibrational temperature of the bending and asymmetric stretching modes from the ratio of even to odd peaks in the rotational Raman spectrum. The contribution from higher vibrational levels is already observable at room temperature as g e/o=0.96/0.04 for CO2 and g e/o=1.16/2.84 for C2H2. The use of the apparent degeneracy to account for higher vibrational levels is demonstrated on spectra measured for a CO2 microwave plasma in the temperature range of 300-3500 K, and shown to be valid up to 1500 K.</p
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