A comprehensive, multi-process box-model approach to glacial-interglacial carbon cycling

The canonical question of which physical, chemical or biological mechanisms were responsible for oceanic uptake of atmospheric CO2 during the last glacial is yet unanswered. Insight from paleo proxies has led to a multitude of hypotheses but none so far have been convincingly supported in three dimensional numerical modelling experiments. The processes that influence the CO2 uptake and export production are inter-related and too complex to solve conceptually while complex numerical models are time consuming and expensive to run which severely limits the combinations of mechanisms that can be explored. Instead, an intermediate inverse box model approach is used here in which the whole parameter space is explored. The glacial circulation and biological production states are derived from these using proxies of glacial export production and the need to draw down CO2 into the ocean. We find that circulation patterns which explain glacial observations include reduced Antarctic Bottom Water formation and high latitude mixing and to a lesser extent reduced equatorial upwelling. The proposed mechanism of CO2 uptake by an increase of eddies in the Southern Ocean, leading to a reduced residual circulation, is not supported. Regarding biological mechanisms, an increase in the nutrient utilization in either the equatorial regions or the northern polar latitudes can reduce atmospheric CO2 and satisfy proxies of glacial export production. Consistent with previous studies, CO2 is drawn down more easily through increased productivity in the Antarctic region than the sub-Antarctic, but that violates observations of lower export production there

Rock-magnetic properties of TRM carrying baked and molten rocks straddling burnt coal seams

The subsurface spontaneous combustion of coal seams in Xinjiang (NW China) during Pleistocene to recent times produced large areas of thermally altered sedimentary rocks with large magnetic moments. The natural remanent magnetization (NRM) and thermoremanent magnetization (TRM) intensities and low-field susceptibilities of such combustion-metamorphic rocks range from 0.1 to 10 A/m and 100 × 10^(-4) to 1000 × 10^(-4) SI, respectively, which is two to three orders of magnitude higher than values typical of their sedimentary protoliths. The dominant magnetic carriers in the burnt rocks appear to include relatively pure forms of magnetite, maghemite and hematite as well as more complex spinel phases. These magnetic phases mainly occur as fine pseudo-single-domain (PSD) particles. Conspicuous is the presence of pure metallic iron (aFe) in some samples. This highly magnetic phase is inferred to appear as more or less elongated super paramagnetic and single-domain (SD) inclusions in host silicate phases, which prevent them from oxidizing. The SD aFe particles can carry a highly stable remanence, having remanent coercivities ranging 70-140mT. The ARM and IRM stability of all burnt rock samples to alternating fields is shown to be relatively high; median destructive fields, B(1/2)A and B(1/2)I, respectively, range of 25-46 and ~20-30mT for dominant spinel-bearing samples, 34-36 and 47-53mT for maghemite-hematite-bearing samples, and 48-89 and 64-84mT for metallic iron-bearing samples. Consequently, burnt rocks are high-quality geomagnetic field recorders. Their very nature makes them useful for paleointensity determinations, although age determination is a limiting factor. Furthermore, remanence intensities and susceptibilities of these magnetically enhanced rocks are sufficient to produce observable magnetic anomalies. This property illustrates the potential to delineate the areal extent and depth of (extinct) coal fires with magnetic exploration. Such information is necessary to refine estimates of hazardous CO2 emission and furthers our understanding of natural coal fires

Hepatic steatosis : metabolic consequences

In this thesis we focused on the causes and consequences of hepatic steatosis. Epidemiological studies in humans, as well as experimental studies in animal models, have shown an association between visceral obesity and dyslipidemia, insulin resistance and type 2 diabetes mellitus. The mechanism underlying this association remains unclear. Recently, attention has focused on the role of excessive accumulation of triglycerides (TG) in the liver (hepatic steatosis) in this association. Hepatic steatosis was considered a benign condition until it was discovered that a nonalcoholic fatty liver is associated with many cardiovascular risk factors. Subsequently, many studies have shown a strong association between hepatic TG content and hepatic insulin resistance. The studies in this thesis show that hepatic steatosis is actively and passively involved in the metabolic disturbances in the glucose and lipid metabolism. The prevalence of hepatic steatosis in western countries is high and will certainly increase with the epidemics of obesity and diabetes. This will put an increasing number of subjects at risk for disturbances in the glucose and lipid metabolism and concomitantly for cardiovascular disease.LEI Universiteit LeidenNWO/ZonMW, Dutch Atherosclerosis society, J.E. Jurriaanse Stichting, TNO Quality of Life, Hope Farms/abdiets, Woerden, Bayer B.V. HealthCare, Boehringer Ingelheim B.V., Novartis Oncology B.V., Eli Lilly Nederland B.V., AstraZeneca B.V., Novo Nordisk Farma B.V.De pathogenese, kliniek en behandeling van arterieel en veneus vaatlijde

The architecture of procurement in sustainable and zero-emission neighborhood projects—strategic challenges and new realities

As an intermediate layer located between buildings and cities, neighborhoods are considered critical with regard to the transition to low-carbon cities and zero-emission societies. Sustainable and zero-emission neighborhood (ZEN) projects can be characterized as both complex and multi-organizational. However, there is currently only limited research available concerning collaboration among organizations in relation to ZEN projects. In particular, there is a lack of evidence as to how lead organizations arrange procurement for ZEN projects. Using a case study approach, this paper explores the potential of procurement to serve as a system integrator in ZEN projects. Our findings indicate that system integration by means of procurement in ZEN projects is difficult due to several challenges. Among the identified challenges, the most important are the complex ownership structure, the lack of supporting regulations, and the unclear mandate of the procurement department. In light of these findings, we propose a conceptual model that lead organizations could apply to support the realization of ZEN projects.</p

On the Lagrangian Realization of Non-Critical W{\cal W}-Strings

A large class of non-critical string theories with extended worldsheet gauge symmetry are described by two coupled, gauged Wess-Zumino-Witten Models. We give a detailed analysis of the gauge invariant action and in particular the gauge fixing procedure and the resulting BRST symmetries. The results are applied to the example of ${\cal W}_3$ strings.Comment: 19 pages, LaTeX (REVTEX macro's

Estimate of the Collins fragmentation function in a chiral invariant approach

We predict the features of the Collins function, which describes the fragmentation of a transversely polarized quark into an unpolarized hadron, by modeling the fragmentation process at a low energy scale. We use the chiral invariant approach of Manohar and Georgi, where constituent quarks and Goldstone bosons are considered as effective degrees of freedom in the non-perturbative regime of QCD. To test the approach we calculate the unpolarized fragmentation function and the transverse momentum distribution of a produced hadron, both of which are described reasonably well. In the case of semi-inclusive deep-inelastic scattering, our estimate of the Collins function in connection with the transversity distribution gives rise to a transverse single spin asymmetry of the order of 10%, supporting the idea of measuring the transversity distribution of the nucleon in this way. In the case of e+ e- annihilation into two hadrons, our model predicts a Collins azimuthal asymmetry of about 5%.Comment: 12 pages, 15 figures. Figs. 11-14 changed, minor changes in discussion, few typos fixed and some references added. Final version to appear in PR

2D Black Hole and Holographic Renormalization Group

In hep-th/0311177, the Large $N$ renormalization group (RG) flows of a modified matrix quantum mechanics on a circle, capable of capturing effects of nonsingets, were shown to have fixed points with negative specific heat. The corresponding rescaling equation of the compactified matter field with respect to the RG scale, identified with the Liouville direction, is used to extract the two dimensional Euclidean black hole metric at the new type of fixed points. Interpreting the large $N$ RG flows as flow velocities in holographic RG in two dimensions, the flow equation of the matter field around the black hole fixed point is shown to be of the same form as the radial evolution equation of the appropriate bulk scalar coupled to 2D black hole.Comment: 21 page

Restraint interventions in people with moderate to profound intellectual disabilities:Perspectives of support staff and family members

Background: Due to incompatibilities in communication, it is key that family members and support staff can take the perspective of people with moderate to profound intellectual disabilities (ID) whilst putting aside their own perspectives. Method: Ten vignettes describing types of restraint interventions (RIs) were presented to 20 unique pairs of support staff and family members related to individuals with moderate to profound ID. Results: In taking their own perspective, more than half of the support staff and family members perceived all RIs as involuntary and severe. In contrast, when asked to put themselves in the position of the client/family member, only three RIs were considered involuntary by a majority of support staff and family members. Conclusions: These results indicate that support staff and family members can take into account the perspective of people with moderate to profound ID in the evaluation and consideration of involuntary care