557 research outputs found
Linking Farm and Market Models to Analyse the Effects of the EU Nitrate Directive for the Dutch Agricultural Sector
This paper presents a modeling system that can be used to analyze the trade off between economy and environment. It takes into account manure policy, farm structure and manure surpluses at farm level as well as the economic effects of manure surpluses at market level. The modeling system consists of two models that are linked to each other by at the one-hand manure prices and distribution of manure over different destinations and at the other hand changes in agricultural and total manure production. One model is the so-called Manure and Ammonia Model (MAM). This model calculates manure surpluses and deficits at the farm level and distribution of manure to own farm, own region, other regions, export abroad and processing at the regional level. Moreover, MAM also calculates ammonia emissions coming from different sources. The second model is a market model that includes the most important agricultural markets. The models are calibrated for 2002. The modeling system is tested to analyze the effects of sharpened manure policies until 2006.farm models, market models, manure, economy, policy, Agricultural and Food Policy,
Controlled auction in het Nederlandse rechtsbestel: De verhouding tussen de contractsvrijheid en de precontractuele fase
Coherent privaatrech
Lift-and-Round to Improve Weighted Completion Time on Unrelated Machines
We consider the problem of scheduling jobs on unrelated machines so as to
minimize the sum of weighted completion times. Our main result is a
-approximation algorithm for some fixed , improving upon the
long-standing bound of 3/2 (independently due to Skutella, Journal of the ACM,
2001, and Sethuraman & Squillante, SODA, 1999). To do this, we first introduce
a new lift-and-project based SDP relaxation for the problem. This is necessary
as the previous convex programming relaxations have an integrality gap of
. Second, we give a new general bipartite-rounding procedure that produces
an assignment with certain strong negative correlation properties.Comment: 21 pages, 4 figure
Weak dipole moment of in collisions with longitudinally polarized electrons
It is pointed out that certain CP-odd momentum correlations in the production
and subsequent decay of tau pairs in collisions get enhanced when the
is longitudinally polarized. Analytic expressions for these correlations
are obtained for the single-pion decay mode of when have
a ``weak" dipole form factor (WDFF) coupling to . For collisions
at the peak, a sensitivity of about 1-5\mbox{ cm} for
the WDFF can be reached using a {\em single} decay
channel, with 's likely to be available at the SLC at Stanford with
polarization of 62\%-75\%.Comment: 9 pages, Latex, PRL-TH-93/17 (Revised
Dietary protein intake and kidney function decline after myocardial infarction:the Alpha Omega Cohort
BACKGROUND: Post-myocardial infarction (MI) patients have a doubled rate of kidney function decline compared with the general population. We investigated the extent to which high intake of total, animal and plant protein are risk factors for accelerated kidney function decline in older stable post-MI patients. METHODS: We analysed 2255 post-MI patients (aged 60-80 years, 80% men) of the Alpha Omega Cohort. Dietary data were collected with a biomarker-validated 203-item food frequency questionnaire. At baseline and 41 months, we estimated glomerular filtration rate based on the Chronic Kidney Disease Epidemiology Collaboration equations for serum cystatin C [estimated glomerular filtration rate (eGFRcysC)] alone and both creatinine and cystatin C (eGFRcr-cysC). RESULTS: Mean [standard deviation (SD)] baseline eGFRcysC and eGFRcr-cysC were 82 (20) and 79 (19) mL/min/1.73 m2. Of all patients, 16% were current smokers and 19% had diabetes. Mean (SD) total protein intake was 71 (19) g/day, of which two-thirds was animal and one-third plant protein. After multivariable adjustment, including age, sex, total energy intake, smoking, diabetes, systolic blood pressure, renin-angiotensin system blocking drugs and fat intake, each incremental total daily protein intake of 0.1 g/kg ideal body weight was associated with an additional annual eGFRcysC decline of -0.12 (95% confidence interval -0.19 to -0.04) mL/min/1.73 m2, and was similar for animal and plant protein. Patients with a daily total protein intake of ≥1.20 compared with <0.80 g/kg ideal body weight had a 2-fold faster annual eGFRcysC decline of -1.60 versus -0.84 mL/min/1.73 m2. Taking eGFRcr-cysC as outcome showed similar results. Strong linear associations were confirmed by restricted cubic spline analyses. CONCLUSION: A higher protein intake was significantly associated with a more rapid kidney function decline in post-MI patients.</p
Climatology of Mid-latitude Ionospheric Disturbances from the Very Large Array Low-frequency Sky Survey
The results of a climatological study of ionospheric disturbances derived
from observations of cosmic sources from the Very Large Array (VLA)
Low-frequency Sky Survey (VLSS) are presented. We have used the ionospheric
corrections applied to the 74 MHz interferometric data within the VLSS imaging
process to obtain fluctuation spectra for the total electron content (TEC)
gradient on spatial scales from a few to hundreds of kilometers and temporal
scales from less than one minute to nearly an hour. The observations sample
nearly all times of day and all seasons. They also span latitudes and
longitudes from 28 deg. N to 40 deg. N and 95 deg. W to 114 deg. W,
respectively. We have binned and averaged the fluctuation spectra according to
time of day, season, and geomagnetic (Kp index) and solar (F10.7) activity.
These spectra provide a detailed, multi-scale account of seasonal and intraday
variations in ionospheric activity with wavelike structures detected at
wavelengths between about 35 and 250 km. In some cases, trends between spectral
power and Kp index and/or F10.7 are also apparent. In addition, the VLSS
observations allow for measurements of the turbulent power spectrum down to
periods of 40 seconds (scales of ~0.4 km at the height of the E-region). While
the level of turbulent activity does not appear to have a strong dependence on
either Kp index or F10.7, it does appear to be more pronounced during the
winter daytime, summer nighttime, and near dusk during the spring.Comment: accepted for publication in Radio Scienc
CP violation at a linear collider with transverse polarization
We show how transverse beam polarization at colliders can provide a
novel means to search for CP violation by observing the distribution of a
single final-state particle without measuring its spin. We suggest an azimuthal
asymmetry which singles out interference terms between standard model
contribution and new-physics scalar or tensor effective interactions in the
limit in which the electron mass is neglected. Such terms are inaccessible with
unpolarized or longitudinally polarized beams. The asymmetry is sensitive to CP
violation when the transverse polarizations of the electron and positron are in
opposite senses. The sensitivity of planned future linear colliders to
new-physics CP violation in is estimated in a
model-independent parametrization. It would be possible to put a bound of TeV on the new-physics scale at the 90% C.L. for
GeV and , with transverse polarizations of
80% and 60% for the electron and positron beams, respectively.Comment: 15 pages, latex, includes 5 figures. This version (v3) corresponds to
publication in Physical Review; extended version of v2 which corresponded to
LC note LC-TH-2003-099 with corrected figure caption
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