2,551 research outputs found
European household waste management schemes: Their effectiveness and applicability in England.
This paper reviews European household waste management schemes and provides an
insight into their effectiveness in reducing or diverting household waste. The
paper also considers the feasibility of replicating such schemes in England.
Selected case studies include those implemented using variable charging schemes,
direct regulation and household incentivisation (reduced disposal charges). A
total of 15 case studies were selected from developed countries in the EU where
some schemes have operated for more than a decade. Criteria for assessing the
effectiveness and replicability of schemes were developed using scheme progress
towards targets, response time, compatibility with government policy, ease of
administration and operation, and public acceptance as attributes. The study
demonstrates the capability of these schemes to significantly reduce household
waste and suggests changes to allow their possible adoption in England. One of
the main barriers to their adoption is the Environmental Protection Act, 1990
that prevents English local authorities (LAs) from implementing the variable
charging method for household waste management. This barrier could be removed
through a change in legislation. The need to derive consistent data and
standardise the method of measuring the effectiveness of schemes is also
highlighted
Martian pedestal craters: Marginal sublimation pits implicate a climate-related formation mechanism
Pedestal craters on Mars are defined by an outward-facing scarp forming a plateau perched tens of meters above the surrounding terrain. Their origin has been attributed to impact armoring of the surface and subsequent removal of inter-crater terrain by either eolian deflation or sublimation of an ice-rich substrate. We identified 2696 pedestal craters between 60N and 60S latitude; 98% are poleward of 33N and 40S. The majority of pedestal crater margins are smoothly sloped, but 3%, concentrated in Utopia Planitia and Malea Planurn, display distinctive marginal pits. These pedestal crater scarps are anomalously tall (usually >80-100 m) and the pits resemble sublimation depressions seen on Earth and elsewhere on Mars, providing evidence for sublimation of volatiles in the scarp, where the armored surface has tapered. The pitted scarps provide insight into the origin of the general pedestal crater population, favoring formation via deposition of a volatile-rich substrate, impact armoring, and sublimation of intervening volatiles. Crater densities and overlapping pedestal craters suggest multiple periods of emplacement and loss of these climate-related, latitude-dependent deposits throughout the Amazonian
Response of benthic nitrogen cycling to estuarine hypoxia
The effects of bottom water oxygen concentration on sediment oxygen uptake, oxygen penetration depth, nitrate and ammonium fluxes, anammox, denitrification, dissimilatory nitrate reduction to ammonium, nitrification, and mineralization were investigated off the Changjiang estuary and its adjacent East China Sea, by combining a seasonal comparison with three artificially induced bottom water oxygen conditions (oxic, ambient, and severe hypoxia). A 50% decrease in in-situ bottom water oxygen concentrations between May and August, led to decreases in the average sediment oxygen uptake and oxygen penetration depth by 23% and 29%, respectively. Anammox rates decreased by a factor of 2.5, and the relative contribution of anammox to the total benthic N-loss decreased from 20% to 7.4%. However, denitrification rates increased, leading to an overall benthic N-loss rate of 0.85 mmol N m(-2)d(-1). At the same time, an increasing contribution of dissimilatory nitrate reduction to ammonium to total nitrate reduction led to higher recycling of inorganic nitrogen during hypoxia in August. Under artificially induced conditions of severe hypoxia, there was a sharp decrease in both sediment oxygen uptake and benthic N-loss rates by 88% and 38%, respectively. Nitrate and ammonium fluxes showed complex behavior at different sites which could be related to the repression of sedimentary nitrification below a bottom water oxygen threshold of 9.7 mu M and increasing dissimilatory nitrate reduction to ammonium. Taken together, our results indicate that changes in benthic nutrient cycling under seasonal hypoxia enhance the retention of both organic and inorganic nitrogen, thereby exacerbating oxygen deficiency
The protective effect of mindfulness and compassion meditation practices on ageing: Hypotheses, models and experimental implementation
Alzheimer's disease (AD) represents a major health and societal issue; there is no treatment to date and the pathophysiological mechanisms underlying this disease are not well understood. Yet, there is hope that AD risk factors and thus the number of AD cases can be significantly reduced by prevention measures based on lifestyle modifications as targeted by non-pharmacological preventive interventions. So far, these interventions have rarely targeted the psycho-affective risk factors related to depression, stress, anxiety, and feeling of loneliness, which are all prevalent in ageing. This paper presents the hypothesis that the regular practice of mindfulness meditation (MM) and loving-kindness and compassion meditation (LKCM) in the ageing population constitutes a lifestyle that is protective against AD. In this model, these practices can promote cognition, mental health, and well-being by strengthening attention control, metacognitive monitoring, emotion regulation and pro-social capacities. Training these capacities could reduce the risk of AD by upregulating beneficial age-related factors such as cognitive reserve, and down-regulating detrimental age-related factors, such as stress, or depression. As an illustration, we present the Medit-Ageing study (public name Silver Santé Study), an on-going European project that assesses the impact and mechanisms of non-pharmacological interventions including meditation, in the ageing population
Effect of stress state and simultaneous hot corrosion on the crack propagation and fatigue life of single crystal superalloy CMSX-4
Operating conditions within industrial gas turbines are changing in response to pressures to reduce environmental impact and enable use of renewable sources. This is driving an increase in the operational temperatures and pressures of combustion in turbine systems. Additionally, diverse operating environments can result in higher sulphur and trace metal contaminant levels, exacerbating hot corrosion in GT systems. Low cycle fatigue (LCF) cycling can also be intensified as a result of increased start/stop shutdowns. The combined effects of hot corrosion and stress are experimentally studied on CMSX-4 single crystal (SC) γ/γ' system under both fatigue and static stress conditions, with either a multi-axial bending or uniaxial stress state. The associated stress intensity thresholds (KTH) under the various stress conditions were evaluated using finite element analysis (FEA). Cracking was observed both under static and fatigue stress conditions in a hot corrosion environment. Crack morphologies were analysed using SEM techniques. Bending stresses and fatigue cycles demonstrated increased crack propagation in the presence of hot corrosion with static uniaxial stresses showing the longest nucleation times and lowest propagation rates
Affective symptoms and risk of progression to mild cognitive impairment or dementia in subjective cognitive decline: A systematic review and meta-analysis
Aims:
To systematically review the literature on outcomes for individuals with subjective cognitive decline (SCD) with concurrent affective symptoms. To conduct a meta-analysis to establish whether either higher depressive symptoms or higher levels of anxiety increased the risk of progression SCD to mild cognitive impairment (MCI) or dementia. /
Methods:
Five databases were searched from inception to February 2021 for longitudinal studies of older adults with SCD, reporting depressive and anxiety symptoms at baseline and risk of MCI or dementia at follow-up. Data were extracted and pooled using a random-effects meta-analysis. /
Results:
Twelve studies were identified. Pooled effect sizes indicated higher depressive symptoms did not increase risk of clinical progression to either MCI (RR = 0.98; 95% CI: 0.75 – 1.26) or dementia (RR = 0.69; 95% CI: 0.27 – 1.79). However, presence of anxiety or SCD-related worry did significantly increase risk of progression from subjective to objective cognitive impairment by 40% (RR = 1.40; 95% CI:1.20 – 1.63). /
Conclusions:
Affective symptoms in the form of anxiety, but not depressive symptoms, increase the risk of progression to objective cognitive impairment in individuals with SCD. Further research should focus on establishing whether psychological interventions aimed at reducing anxiety and worry also reduce the risk of clinical progression
Long range transport of ultra cold atoms in a far-detuned 1D optical lattice
We present a novel method to transport ultra cold atoms in a focused optical
lattice over macroscopic distances of many Rayleigh ranges. With this method
ultra cold atoms were transported over 5 cm in 250 ms without significant atom
loss or heating. By translating the interference pattern together with the beam
geometry the trap parameters are maintained over the full transport range.
Thus, the presented method is well suited for tightly focused optical lattices
that have sufficient trap depth only close to the focus. Tight focusing is
usually required for far-detuned optical traps or traps that require high laser
intensity for other reasons. The transport time is short and thus compatible
with the operation of an optical lattice clock in which atoms are probed in a
well designed environment spatially separated from the preparation and
detection region.Comment: 14 pages, 6 figure
- …