767 research outputs found
Global Governance for Environmentally Sustainable Food Systems: Certified Organics in a North â South and South-South Perspective
Challenged to consume with less environmental impact, consumers buy certified organic products to âproxyâ
environmental governance. The paper explores how far certified organic agriculture is institutionally embedded in
Brazil, China, and Egypt. The three case studies illustrate how regulation, including standard-setting and certification
processes differ between south and north, in terms of the evolution and nature of certification, as well as stakeholders and agency involved in shaping the regulation. A comparative analysis is presented on south-south differences in this regard along with some possible explanations of these. The paper finally discusses the perspectives in the global success of organic certification and whether it has potential to transform global agriculture towards higher overall levels of sustainability
Method of bonding metals with a radio-opaque adhesive/sealant for void detection and product made
A method and structure for providing radio-opaque polymer compounds for use in metal bonding and sealing. A powder filler comprising a high atomic number metal or compound thereof is incorporated into a polymer compound to render it more radio-opaque than the surrounding metal structures. Voids or other discontinuities in the radio-opaque polymer compound can then be detected by x-ray inspection or other non-destructive radiographic procedure
Beyond time-homogeneity for continuous-time multistate Markov models
Multistate Markov models are a canonical parametric approach for data
modeling of observed or latent stochastic processes supported on a finite state
space. Continuous-time Markov processes describe data that are observed
irregularly over time, as is often the case in longitudinal medical and
biological data sets, for example. Assuming that a continuous-time Markov
process is time-homogeneous, a closed-form likelihood function can be derived
from the Kolmogorov forward equations -- a system of differential equations
with a well-known matrix-exponential solution. Unfortunately, however, the
forward equations do not admit an analytical solution for continuous-time,
time-inhomogeneous Markov processes, and so researchers and practitioners often
make the simplifying assumption that the process is piecewise time-homogeneous.
In this paper, we provide intuitions and illustrations of the potential biases
for parameter estimation that may ensue in the more realistic scenario that the
piecewise-homogeneous assumption is violated, and we advocate for a solution
for likelihood computation in a truly time-inhomogeneous fashion. Particular
focus is afforded to the context of multistate Markov models that allow for
state label misclassifications, which applies more broadly to hidden Markov
models (HMMs), and Bayesian computations bypass the necessity for
computationally demanding numerical gradient approximations for obtaining
maximum likelihood estimates (MLEs)
Sow body condition at weaning and reproduction performance in organic piglet production
The objective was to investigate the variation in backfat at weaning and its relations to reproduction results in organic sow herds in Denmark. The study included eight herds and 573 sows. The average backfat at weaning meanïżœ13 mm; SDïżœ4.2 mm) ranging from 10.5 to 17.3 mm among herds shows that it is possible to avoid poor body condition at weaning even with a lactation length of seven weeks or more. No main effect of backfat at weaning on reproduction performance was found, but the probability of a successful reproduction after weaning tended to decrease with decreasing backfat for first parity sows, whereas the opposite was the case for multiparous sows
As a Matter of Factions: The Budgetary Implications of Shifting Factional Control in Japanâs LDP
For 38 years, the Liberal Democratic Party (LDP) maintained single-party control over the Japanese government. This lack of partisan turnover in government has frustrated attempts to explain Japanese government policy changes using political variables. In this paper, we look for intraparty changes that may have led to changes in Japanese budgetary policy. Using a simple model of agenda-setting, we hypothesize that changes in which intraparty factions âcontrolâ the LDP affect the partyâs decisions over spending priorities systematically. This runs contrary to the received wisdom in the voluminous literature on LDP factions, which asserts that factions, whatever their raison dâĂȘtre, do not exhibit different policy preferences. We find that strong correlations do exist between which factions comprise the agenda-setting party âmainstreamâ and how the government allocates spending across pork-barrel and public goods items
Afrika â Fremtidens Ăkologiske Kontinent?
Afrikanske bĂžnders forbrug af fossil energi er lavt â og deres forurening med nitrat, sprĂžjtegifte og klimagasser er begrĂŠnset
Magnetic levitation by rotation
A permanent magnet can be levitated simply by placing it in the vicinity of
another permanent magnet that rotates in the order of 200 Hz. This surprising
effect can be easily reproduced in the lab with off-the-shelf components. Here
we investigate this novel type of magnetic levitation experimentally and
clarify the underlying physics. Using a 19 mm diameter spherical NdFeB magnet
as rotor magnet, we capture the detailed motion of levitating, spherical NdFeB
magnets, denoted floater magnets. We find that as levitation occurs, the
floater magnet frequency-locks with the rotor magnet, and, noticeably, that the
magnetization of the floater is oriented close to the axis of rotation and
towards the like pole of the rotor magnet. This is in contrast to what might be
expected by the laws of magnetostatics as the floater is observed to align its
magnetization essentially perpendicular to the magnetic field of the rotor.
Moreover, we find that the size of the floater has a clear influence on the
levitation: the smaller the floater, the higher the rotor speed necessary to
achieve levitation, and the further away the levitation point shifts. We verify
that magnetostatic interactions between the rotating magnets are responsible
for creating the equilibrium position of the floater. Hence, this type of
magnetic levitation does not rely on gravity as a balancing force to achieve an
equilibrium position. Based on theoretical arguments and a numerical model, we
show that a constant, vertical field and eddy-current enhanced damping is
sufficient to produce levitation from rest. This enables a gyroscopically
stabilised counter-intuitive steady-state moment orientation, and the resulting
magnetostatically stable, mid-air equilibrium point. The numerical model
display the same trends with respect to rotation speed and the floater magnet
size as seen in the experiments.Comment: 15 pages, 6 figures, 10 videos + 8 pages supplementary material.
Videos available at
https://youtube.com/playlist?list=PLOfbFSFa_WoK4PgYQXhuNucS_WcIxXDE
Organic carbon controls water retention and plant available water in cultivated soils from South Greenland
Combining Laser-Induced Breakdown Spectroscopy (LIBS) and Visible Near-Infrared Spectroscopy (VisâNIRS) for Soil Phosphorus Determination
Conventional wet chemical methods for the determination of soil phosphorus (P) pools, relevant for environmental and agronomic purposes, are labor-intensive. Therefore, alternative techniques are needed, and a combination of the spectroscopic techniques—in this case, laser-induced breakdown spectroscopy (LIBS)—and visible near-infrared spectroscopy (vis-NIRS) could be relevant. We aimed at exploring LIBS, vis-NIRS and their combination for soil P estimation. We analyzed 147 Danish agricultural soils with LIBS and vis-NIRS. As reference measurements, we analyzed water-extractable P (Pwater), Olsen P (Polsen), oxalate-extractable P (Pox) and total P (TP) by conventional wet chemical protocols, as proxies for respectively leachable, plant-available, adsorbed inorganic P, and TP in soil. Partial least squares regression (PLSR) models combined with interval partial least squares (iPLS) and competitive adaptive reweighted sampling (CARS) variable selection methods were tested, and the relevant wavelengths for soil P determination were identified. LIBS exhibited better results compared to vis-NIRS for all P models, except for Pwater, for which results were comparable. Model performance for both the LIBS and vis-NIRS techniques as well as the combined LIBS-vis-NIR approach was significantly improved when variable selection was applied. CARS performed better than iPLS in almost all cases. Combined LIBS and vis-NIRS models with variable selection showed the best results for all four P pools, except for Pox where the results were comparable to using the LIBS model with CARS. Merging LIBS and vis-NIRS with variable selection showed potential for improving soil P determinations, but larger and independent validation datasets should be tested in future studies
Springtime nitrogen oxides and tropospheric ozone in Svalbard: results from the measurement station network
Svalbard is a remote and scarcely populated Arctic archipelago and is considered to be mostly influenced by long-range-transported air pollution. However, there are also local emission sources such as coal and diesel power plants, snowmobiles and ships, but their influence on the background concentrations of trace gases has not been thoroughly assessed. This study is based on data of tropospheric ozone (O3) and nitrogen oxides (NOx) collected in three main Svalbard settlements in spring 2017. In addition to these ground-based observations and radiosonde and O3 sonde soundings, ERA5 reanalysis and BrO satellite data have been applied in order to distinguish the impact of local and synoptic-scale conditions on the NOx and O3 chemistry. The measurement campaign was divided into several sub-periods based on the prevailing large-scale weather regimes. The local wind direction at the stations depended on the large-scale conditions but was modified due to complex topography. The NOx concentration showed weak correlation for the different stations and depended strongly on the wind direction and atmospheric stability. Conversely, the O3 concentration was highly correlated among the different measurement sites and was controlled by the long-range atmospheric transport to Svalbard. Lagrangian backward trajectories have been used to examine the origin and path of the air masses during the campaign.publishedVersio
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