210 research outputs found
Palaeoecological study of a Weichselian wetland site in the Netherlands suggests a link with Dansgaard-Oeschger climate oscillation
Botanical microfossils, macroremains and oribatid mites of a Weichselian interstadial deposit in the central Netherlands point to a temporary, sub-arctic wetland in a treeless landscape. Radiocarbon dates and OSL dates show an age between ca. 54.6 and 46.6 ka cal BP. The vegetation succession, starting as a peat-forming wetland that developed into a lake, might well be linked with a Dansgaard-Oeschger climatic cycle. We suggest that during the rapid warming at the start of a D-O cycle, relatively low areas in the landscape became wetlands where peat was formed. During the more gradual temperature decline that followed, evaporation diminished; the wetlands became inundated and lake sediments were formed. During subsequent sub-arctic conditions the interstadial deposits were covered with wind-blown sand. Apart from changes in effective precipitation also the climate-related presence and absence of permafrost conditions may have played a role in the formation of the observed sedimentological sequence from sand to peat, through lacustrine sediment, with coversand on top. The Wageningen sequence may correspond with D-O event 12, 13 or 14. Some hitherto not recorded microfossils were described and illustrated
The polypill in the primary prevention of cardiovascular disease: cost-effectiveness in the Dutch population
OBJECTIVES: The aim of the present study was to estimate the cost-effectiveness of the polypill in the primary prevention of cardiovascular disease. DESIGN: A health economic modeling study. SETTING: Primary health care in the Netherlands. PARTICIPANTS: Simulated individuals from the general Dutch population, aged 45-75 years of age. INTERVENTIONS: Opportunistic screening followed by prescription of the polypill to eligible individuals. Eligibility was defined as having a minimum 10-year risk of cardiovascular death as assessed with the SCORE function of alternatively 5%, 7.5%, or 10%. Different versions of the polypill were considered, depending on composition: 1) the Indian polycap, with three different types of blood pressure lowering drugs, a statin, and aspirin; 2) as 1) but without aspirin; 3) as 2) but with a double statin dose. In addition, a scenario of (targeted) separate antihypertensive and/or statin medication was simulated. PRIMARY OUTCOME MEASURES: Cases of acute myocardial infarction or stroke prevented, QALYs gained, and the costs per QALY gained. All interventions were compared with usual care. RESULTS: All scenarios were cost-effective with an incremental cost-effectiveness ratio between €7,900-12,300 per QALY compared with usual care. Most health gains were achieved with the polypill without aspirin and containing a double dose of statins. With a 10-year risk of 7.5% as threshold, this pill would prevent approximately 3.5% of all cardiovascular events. CONCLUSIONS: Opportunistic screening based on global cardiovascular risk assessment followed by polypill prescription to those with increased risk offers a cost-effective strategy. Most health gain is achieved by the polypill without aspirin and a double statin dose
Calf and dam characteristics and calf transport age affect immunoglobulin titers and hematological parameters of veal calves
This study aimed to investigate effects of transport
age of calves (14 vs. 28 d), and of calf and dam characteristics,
on immunoglobulin titers and hematological
variables of veal calves. Calves (n = 683) were transported
to a veal farm at 14 or 28 d of age. Natural antibodies
N-IgG, N-IgM, and N-IgA against phosphorylcholine
conjugated to bovine serum albumin (PC-BSA)
were measured in serum of the dams 1 wk before calving
and in first colostrum. These antibodies were also
measured in serum of calves 1 wk after birth, 1 d before
transport, and in wk 2 and 10 posttransport at the veal
farm. Hematological variables were assessed in calves 1
d before transport and in wk 2 posttransport. One day
before transport, titers of N-IgG, N-IgM, N-IgA, and
neutrophil counts were higher, and lymphocyte counts
were lower in 14-d-old calves compared with 28-d-old
calves. In wk 2 at the veal farm, calves transported
at 14 d of age had higher N-IgG titers and neutrophil
counts, but lower N-IgM and N-IgA titers, and lymphocyte
counts than calves transported at 28 d. In wk 1
and 1 d before transport, N-Ig in calves were positively
related to N-Ig in colostrum. In wk 2 and 10 at the veal
farm, N-IgG in calves was positively related to N-IgG
in colostrum. The N-IgG titers in calves at the dairy farm were negatively related to the likelihood of being
individually treated with antibiotics or other medicines
at the veal farm. Our results suggest that calves transported
to the veal farm at 28 d of age showed a more
advanced development of their adaptive immunity than calves transported at 14 d of age. Quality of colostrum
might have long-term consequences for N-IgG titers
and immunity in veal calves.Stichting Brancheorganisatie Kalversector (SBK, Nieuwegein, the Netherlands), ZuivelNL (the organization of the Dutch dairy sector, Den Haag, the Netherlands), and the Dutch Ministry of Agriculture, Nature and Food Quality (Den Haag, the Netherlands).http://www.journals.elsevier.com/journal-of-dairy-science/am2022Veterinary Tropical Disease
A model for the dynamics and internal structure of planar doping fronts in organic semiconductors
The dynamics and internal structure of doping fronts in organic
semiconductors are investigated theoretically using an extended drift-diffusion
model for ions, electrons and holes. The model also involves the injection
barriers for electrons and holes in the partially doped regions in the form of
the Nernst equation, together with a strong dependence of the electron and hole
mobility on concentrations. Closed expressions for the front velocities and the
ion concentrations in the doped regions are obtained. The analytical theory is
employed to describe the acceleration of the p- and n-fronts towards each
other. The analytical results show very good agreement with the experimental
data. Furthermore, it is shown that the internal structure of the doping fronts
is determined by the diffusion and mobility processes. The asymptotic behavior
of the concentrations and the electric field is studied analytically inside the
doping fronts. The numerical solution for the front structure confirms the most
important predictions of the analytical theory: a sharp head of the front in
the undoped region, a smooth relaxation tail in the doped region, and a plateau
at the critical point of transition from doped to undoped regions.Comment: 13 pages, 11 figure
Wages in high-tech start-ups - do academic spin-offs pay a wage premium?
Due to their origin from universities, academic spin‐offs operate at the forefront of the
technological development. Therefore, spin‐offs exhibit a skill‐biased labour demand, i.e. spin‐offs
have a high demand for employees with cutting edge knowledge and technical skills. In order to accommodate
this demand, spin‐offs may have to pay a relative wage premium compared to other
high‐tech start‐ups. However, neither a comprehensive theoretical assessment nor the empirical
literature on wages in start‐ups unambiguously predicts the existence and the direction of wage differentials
between spin‐offs and non‐spin‐offs. This paper addresses this research gap and examines
empirically whether or not spin‐offs pay their employees a wage premium. Using a unique linked
employer‐employee data set of German high‐tech start‐ups, we estimate Mincer‐type wage regressions
applying the Hausman‐Taylor panel estimator. Our results show that spin‐offs do not pay a
wage premium in general. However, a notable exception from this general result is that spin‐offs that
commercialise new scientific results or methods provide higher wages to employees with linkages to
the university sector – either as university graduates or as student workers
Dairy calves' personality traits predict social proximity and response to an emotional challenge
Abstract The assessment of individual traits requires that tests are reliable (i.e. consistency over time) and externally valid, meaning that they predict future responses in similar contexts (i.e. convergent validity) but do not predict responses to unrelated situations (i.e. discriminant validity). The aim of this study was to determine if dairy calf personality traits (Fearfulness, Sociability and Pessimism), derived from behaviours expressed in standardized tests, predict individuals’ responses in related situations. The first experiment tested if the trait ‘Sociability’ was related to the expression of social behaviour in the home-pen, with calves assigned individual proximity scores (based on proximity to other calves) while they were in their home-pen at approximately 113 and 118 d of age. The second experiment aimed at exploring whether traits ‘Fearfulness’ and ‘Pessimism’ were related to the calves’ emotional response to transportation. All calves were subjected to two 10-min transportation challenges done on two consecutive days. Emotional response was assessed using the maximum eye temperature (measured using infrared thermography) and the number of vocalizations emitted. Social proximity scores (Experiment 1), vocalizations emitted and maximum eye temperature after loading (Experiment 2) were consistent over time. In addition, the results showed good convergent validity with calves scoring higher in Sociability also having higher proximity scores in the home-pen, and animals scoring higher in Fearfulness and Pessimism showing a more intense emotional response to transportation. The results also showed good discriminant validity, as neither Fearfulness nor Pessimism were associated with the expression of social behaviours (Experiment 1) and Sociability was not associated with the animal’s emotional response to transportation (Experiment 2). We conclude that the methodology used to measure personality traits shows good reliability and external validity
Order/disorder phase transition in cordierite and its possible relationship to the development of symplectite reaction textures in granulites
Based on a consistent set of empirical interatomic potentials, static structure energy calculations of various Al/Si configurations in the supercell of Mg-cordierite and Monte Carlo simulations the phase transition between the orthorhombic and hexagonal modifications of cordierite (Crd) is predicted at 1623 K. The temperature dependences of the enthalpy, entropy, and free energy of the Al/Si disorder were calculated using the method of thermodynamic integration. The simulations suggest that the commonly observed crystallization of cordierite in the disordered hexagonal form could be related to a tendency of Al to occupy T1 site, which is driven by local charge balance. The increase in the Al fraction in the T1 site over the ratio of 2/3(T1): 1/3(T2), that characterizes the ordered state, precludes formation of the domains of the orthorhombic phase. This intrinsic tendency to the crystallization of the metastable hexagonal phase could have significantly postponed the formation of the association of orthorhombic cordierite and orthopyroxene over the association of quartz and garnet in metapelites subjected to granulite facies metamorphism. The textures of local metasomatic replacement (the formation of Crd + Opx or Spr + Crd symplectites between the grains of garnet and quartz) indicate the thermodynamic instability of the association of Qtz + Grt at the moment of the metasomatic reaction. This instability could have been caused by the difficulty of equilibrium nucleation of orthorhombic cordierite
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