12,895 research outputs found
KRW-maatlat macrofauna voor zoet getijdenwater (R8). Hoofdrapport
In opdracht van de Waterdienst (voorheen RIZA) is met behulp van de beschikbare RWS gegevens vanaf 1992 voor zoet getijdenwater (R8) een macrofauna maatlat opgesteld waarin oever (litoraal), bodem (profundaal) en sedimentverontreiniging zijn opgenomen. Deze maatlat wordt in dit rapport beschreven. De maatlat is opgeleverd in twee rapporten, het onderliggende hoofdrapport en een achtergrondrapport (Peeters et al., 2010) met een uitgebreide beschrijving van de werkzaamheden en verantwoording van de gemaakte keuzes. In hoofdstuk 2 is de aanpak van de ontwikkeling van de maatlat beschreven. Hoofdstuk 3 geeft een globale referentiebeschrijving van zoet getijdenwater (R8). Hoofdstuk 4 beschrijft de deelmaatlatten waaruit de maatlat macrofauna is opgebouwd. In hoofdstuk 5 wordt de berekening van de afzonderlijke deelmaatlatten uitgelegd en de berekening van de Ecologische Kwaliteitsratio (EKR). In hoofdstuk 6 wordt de werking van de maatlat geïllustreerd met een uitgewerkt voorbeeld. Het hoofdrapport wordt afgesloten met discussiepunten en aanbevelingen (hoofdstuk 7)
Achtergrondrapport KRW maatlat macrofauna R8. Bewerking en analyse data
In opdracht van de Waterdienst (voorheen RIZA) is met behulp van de beschikbare RWS gegevens vanaf 1992 voor zoet getijdenwater (R8) een macrofauna maatlat opgesteld waarin oever (litoraal), bodem (profundaal) en sedimentverontreiniging zijn opgenomen. De maatlat is opgeleverd in twee rapporten, het hoofdrapport (Peeters et al., 2010) en dit onderliggende achtergrondrapport met een uitgebreide beschrijving van de werkzaamheden en verantwoording van de gemaakte keuzes. Dit rapport bevat een beschrijving van de gebruikte data, de bewerkingen van de data, de analysetechnieken en aanvullende gegevens die gebruikt zijn bij het opstellen van de maatlat macrofauna R8
Phase space geometry in scalar-tensor cosmology
We study the phase space of spatially homogeneous and isotropic cosmology in
general scalar-tensor theories. A reduction to a two-dimensional phase space is
performed when possible-in these situations the phase space is usually a
two-dimensional curved surface embedded in a three-dimensional space and
composed of two sheets attached to each other, possibly with complicated
topology. The results obtained are independent of the choice of the coupling
function of the theory and, in certain situations, also of the potential.Comment: 18 pages, 9 figures, latex, to appear in Ann. Phys. (NY
Talking in the present, caring for the future: Language and environment
This paper identifies a new source that explains environmental behaviour: the presence of future
tense marking in language. We predict that languages that grammatically mark the future affect speakers' intertemporal preferences and thereby reduce their willingness to address environmental problems. We first show that speakers of languages with future tense marking are less likely to adopt environmentally responsible behaviours and to support policies to prevent environmental damage. We then document that this effect holds across countries: future tense marking is an important determinant of climate change policies and global environmental cooperation. The results suggest that there may be deep and surprising obstacles for attempts to address climate change
Timing manipulations reveal the lack of a causal link across timing of annual-cycle stages in a long-distance migrant
Organisms need to time their annual-cycle stages, like breeding and migration, to occur at the right time of the year. Climate change has shifted the timing of annual-cycle stages at different rates, thereby tightening or lifting time constraints of these annual-cycle stages, a rarely studied consequence of climate change. The degree to which these constraints are affected by climate change depends on whether consecutive stages are causally linked (scenario I) or whether the timing of each stage is independent of other stages (scenario II). Under scenario I, a change in timing in one stage has knock-on timing effects on subsequent stages, whereas under scenario II, a shift in the timing of one stage affects the degree of overlap with previous and subsequent stages. To test this, we combined field manipulations, captivity measurements and geolocation data. We advanced and delayed hatching dates in pied flycatchers (Ficedula hypoleuca) and measured how the timing of subsequent stages (male moult and migration) were affected. There was no causal effect of manipulated hatching dates on the onset of moult and departure to Africa. Thus, advancing hatching dates reduced the male moult–breeding overlap with no effect on the moult–migration interval. Interestingly, the wintering location of delayed males was more westwards, suggesting that delaying the termination of breeding carries over to winter location. Because we found no causal linkage of the timing of annual-cycle stages, climate change could shift these stages at different rates, with the risk that the time available for some becomes so short that this will have major fitness consequences
Gravity and Crossing the Phantom Divide Barrier
The gravity models formulated in Einstein conformal frame are
equivalent to Einstein gravity together with a minimally coupled scalar field.
We shall explore phantom behavior of models in this frame and compare
the results with those of the usual notion of phantom scalar field.Comment: 13 Pages, 9 figures. To appear in Physics Letters
Antimicrobial susceptibility of organisms causing community-acquired urinary tract infections in Gauteng Province, South Africa
Background. Patients with community-acquired urinary tract infections (UTIs) frequently present to healthcare facilities in South Africa (SA).Aim. To provide information on UTI aetiology and antimicrobial susceptibility of pathogens.Methods. We recruited women with UTI-related symptoms, who tested positive for .2 urine dipstick criteria (proteinuria, blood, leucocytes or nitrites) at 1 public and 5 private primary healthcare facilities in 2011. Demographic and clinical data were recorded and mid-stream urine (MSU) specimens were cultured. UTI pathogens were Gram-stained and identified to species level. Etest-based antimicrobial susceptibility testing was performed for amoxicillin/clavulanic acid, cefixime, cefuroxime, ciprofloxacin, fosfomycin, levofloxacin, nitrofurantoin, norfloxacin and trimethoprim/sulphamethoxazole.Results. Of the 460 women recruited, 425 MSU samples were processed and 204 UTI pathogens were identified in 201 samples. Most pathogens were Gram-negative bacilli (GNB) (182; 89.2%) and 22 (10.8%) were Gram-positive cocci (GPC). Escherichia coli was the most frequent GNB (160; 79.6%), while Enterococcus faecalis was the predominant GPC (8; 4.0%). The UTI pathogens had similar susceptibility profiles for fosfomycin (95.5%; 95% confidence interval (CI) 92.6 - 98.4), the 3 fluoroquinolones (94.1%; 95% CI 90.8 - 97.4), nitrofurantoin (91.7%; 95% CI 87.8 - 95.6), cefuroxime (90.1%; 95% CI 86.0 - 94.3) and cefixime (88.2%; 95% CI 83.7 - 92.6). UTI pathogens were less susceptible to amoxicillin/clavulanic acid (82.8%; 95% CI 77.5 - 88.0) when compared with fluoroquinolones and fosfomycin. Trimethoprim/ sulphamethoxazole was the least efficacious antimicrobial agent (44.3% susceptible; 95% CI 37.4 - 51.2).Conclusion. This study provides relevant data for the empirical treatment of community-acquired UTIs in SA
An algebraic SU(1,1) solution for the relativistic hydrogen atom
The bound eigenfunctions and spectrum of a Dirac hydrogen atom are found
taking advantage of the Lie algebra in which the radial part of the
problem can be expressed. For defining the algebra we need to add to the
description an additional angular variable playing essentially the role of a
phase. The operators spanning the algebra are used for defining ladder
operators for the radial eigenfunctions of the relativistic hydrogen atom and
for evaluating its energy spectrum. The status of the Johnson-Lippman operator
in this algebra is also investigated.Comment: to appear in Physics Letters A (2005). We corrected a misprint in
page 7, in the paragraph baggining with "With the value of ..." the ground
state should be |\lambda, \lambda>, not |\lambda, \lambda+1
The Rapid Build-up of Massive Early-type Galaxies. Supersolar Metallicity, High Velocity Dispersion and Young Age for an ETG at z=3.35
Thanks to very deep spectroscopic observations carried out at the Large
Binocular Telescope, we measured simultaneously stellar age, metallicity and
velocity dispersion for C1-23152, an ETG at redshift =3.352, corresponding
to an epoch when the Universe was 1.8 Gyr old. The analysis of its
spectrum shows that this galaxy, hosting an AGN, formed and assembled
210 M shaping its morphology within the 600
Myr preceding the observations, since 4.6. The stellar population has
a mean mass-weighted age 400 Myr and it is formed between
600 Myr and 150 Myr before the observed epoch, this latter being
the time since quenching. Its high stellar velocity dispersion,
=40960 km s, confirms the high mass
(M=10 M) and the high mass density
(= M
kpc), suggesting a fast dissipative process at its origin. The analysis
points toward a supersolar metallicity, [Z/H]=0.25, in
agreement with the above picture, suggesting a star formation efficiency much
higher than the replenishment time. However, sub-solar metallicity values
cannot be firmly ruled out by our analysis. Quenching must have been extremely
efficient to reduce the star formation to SFR6.5 M yr in less
than 150 Myr. This could be explained by the presence of the AGN, even if a
causal relation cannot be established from the data. C1-23152 has the same
stellar and physical properties of the densest ETGs in the local Universe of
comparable mass, suggesting that they are C1-23152-like galaxies which evolved
to unperturbed.Comment: 20 pages, 12 figures. Accepted for publication in ApJ (revised to
match the ApJ version
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