This paper discusses results from the second phase of the European Ice Sheet Modelling Initiative (EISMINT). It reports the intercomparison of ten operational ice-sheet models and uses a series of ...experiments to examine the implications of thermomechanical coupling for model behaviour. A schematic, circular ice sheet is used in the work which investigates both steady states and the response to stepped changes in climate. The major finding is that the radial symmetry implied in the experimental design can, under certain circumstances, break down with the formation of distinct, regularly spaced spokes of cold ice which extended from the interior of the ice sheet outward to the surrounding zone of basal melt. These features also manifest themselves in the thickness and velocity distributions predicted by the models. They appear to be a common feature to all of the models which took part in the intercomparison, and may stem from interactions between ice temperature, flow and surface form. The exact nature of these features varies between models, and their existence appears to be controlled by the overall thermal regime of the ice sheet. A second result is that there is considerable agreement between the models in their predictions of global-scale response to imposed climate change.
A novel concept for the metal-free synthesis of block copolymers combining enzymatic ring-opening polymerization and nitroxide-mediated living free-radical polymerization from a bifunctional ...initiator is presented. Block copolymers comprising a poly(styrene) and poly(caprolactone) block were obtained in two consecutive polymerization steps (macroinitiation) and in a one-pot cascade approach without intermediate transformation or work up step. By optimization of the reaction conditions a high selectivity of both transformations could be realized in the cascade polymerization, resulting in high block copolymer yields. The same concept was successfully applied to enzymatic resolution polymerization of racemic 4-methyl-ε-caprolactone combined with the living free-radical polymerization of styrene yielding block copolymers with high enantiomeric excess in the 4-methyl-ε-caprolactone block.
Background. Extreme fear of delivery with request of cesarean section is a problem. The obstetric outcome in women given psychological and obstetric support is described.
Methods. Women, ...consecutively referred to the Psychosomatic outpatient clinic because of fear of delivery (n= 100), were compared to a matched reference group (n=100).
Results. The women in the study group had higher frequency of psychic problems than the references. The majority, 68 of the women (68%) initially requested cesarean section (CS). After individualized psychological and obstetrical support, 38 of these women agreed to vaginal delivery (38%) and 30 had an elective CS (30%). In the end another 13 (13%) women had a CS for obstetric or mixed reasons. Complication rate was low and similar in the groups. The 57 women who eventually had a vaginal delivery (57%) showed an obstetric outcome similar to the reference group. They had a higher frequency of induction of labor (p=0.02), and of epidural and pudendal blocks for pain relief (p=0.002 and 0.05 respectively). They had shorter labor time (p=0.05). The cost of the psychological therapy was well compensated for by the savings due to the reduction in the number of CS.
Conclusions. Psychosomatic support for women with severe fear of delivery resulted in a 50% reduction of CS for psychosocial indications and vaginal deliveries similar to a reference group. The cost of psychosomatic support was less than savings due to fewer cesarean sections.
Acoustics and perception of overtone singing Bloothooft, G; Bringmann, E; van Cappellen, M ...
The Journal of the Acoustical Society of America,
10/1992, Letnik:
92, Številka:
4 Pt 1
Journal Article
Recenzirano
Overtone singing, a technique of Asian origin, is a special type of voice production resulting in a very pronounced, high and separate tone that can be heard over a more or less constant drone. An ...acoustic analysis is presented of the phenomenon and the results are described in terms of the classical theory of speech production. The overtone sound may be interpreted as the result of an interaction of closely spaced formants. For the lower overtones, these may be the first and second formant, separated from the lower harmonics by a nasal pole-zero pair, as the result of a nasalized articulation shifting from /c/ to /a/, or, as an alternative, the second formant alone, separated from the first formant by the nasal pole-zero pair, again as the result of a nasalized articulation around /c/. For overtones with a frequency higher than 800 Hz, the overtone sound can be explained as a combination of the second and third formant as the result of a careful, retroflex, and rounded articulation from /c/, via schwa /e/ to /y/ and /i/ for the highest overtones. The results indicate a firm and relatively long closure of the glottis during overtone phonation. The corresponding short open duration of the glottis introduces a glottal formant that may enhance the amplitude of the intended overtone. Perception experiments showed that listeners categorized the overtone sounds differently from normally sung vowels, which possibly has its basis in an independent perception of the small bandwidth of the resonance underlying the overtone. Their verbal judgments were in agreement with the presented phonetic-acoustic explanation.
A medium-length ice core was drilled at the ice divide on the Lomonosovfonna plateau (1230 m a.s.l.), Svalbard, in May 1997. As part of this project, temperature measurements were performed in the ...120m deep borehole. At this site the ice thickness based on radar measurements is 126.5 m and the mean annual accumulation rate is 380 kg m–3. the measurements over the 15–120m depth interval show a nearly isothermal profile with a mean value of –2.8˚C and a standard deviation of 0.2˚C. the measurements reveal a temperature minimum at approximately 70m depth and a temperature gradient of 0.011 ±0.004˚Cm–1 near the bottom. the temperature minimum and relatively low temperature gradient cannot be explained in terms of a steady-state climate. Numerical calculations with a simple one-dimensional diffusion–advection model show that the temperature increased at a maximum rate of 0.02–0.025Ka–1 over the last 100 years, the total temperature increase amounting to 2.0–3.0K. Forcing the model with the observed record at Svalbard airport revealed that in the 19th century the surface temperature was at most 2.5 K lower, and that the instrumental observations started during a period with temperatures comparable to the end of the 19th century. the data are of particular interest for historical simulations since often no other temperature data are available in polar areas.
This paper sets out to place IOR activities for offshore oil fields in a modern reservoir management perspective. Looking for additional oil reserves by IOR technology seems to be a valuable ...supplement to exploration drilling in the North Sea. It also appears to be the right timing for some of our fields, because we have to integrate IOR technology in primary phase production. Four major aspects of IOR activities are mentioned: (1) reservoir description, (2) recovery mechanisms, (3) field predictions, (4) field operation. Several reservoir management tools developed and under rapid development are mentioned and it is also pointed at how these ought to be integrated to yield better results. A field study example is given for Gullfaks, where polymer (Xanthan) is considered added to injection water to improve sweep efficiency. Cet article vise à placer des activités de récupération améliorée des hydrocarbures (Improved Oil Recovery, IOR) dans la perspective d'une stratégie moderne d'exploitation des gisements. La recherche de réserves supplémentaires d'huile par les techniques de récupération améliorée complète et valorise l'activité de forage d'exploration en mer du Nord. Le temps nous paraît être venu d'appliquer cette démarche à certains de nos gisements, car nous devons ajouter les technologies de récupération améliorée à la phase de production primaire. Quatre aspects importants des techniques de récupération améliorée sont indiqués : - la description des réservoirs; - les mécanismes de récupération; - la prédiction du comportement des gisements; - les opérations sur champ. Plusieurs outils visant à l'exploitation des gisements, déjà opérationnels ou en cours de développement, sont mentionnés. On indique la manière de les prendre en compte pour obtenir de meilleurs résultats. Un exemple d'étude de gisement est présenté pour Gullfaks, où il est envisagé d'ajouter des polymères (xanthanes) à l'eau d'injection pour améliorer le coefficient de balayage.
In a socio-economically stable community with free access to medical care, a prospective comparison was made of pregnancy, delivery and neonatal data concerning 480 grand multiparas (> or = 5 ...deliveries) and 325 controls. The mean diastolic blood pressure was slightly higher (79.8 vs. 77.8 mmHg) among the grand multiparas and the rates of episiotomy differed greatly (5.8% in the grand multiparas vs. 45.7% in the controls). The main clinical difference was a slightly higher incidence of placental complications-i.e., praevia, abruptio and retentio (3.4% vs. 0.9%; P < 0.05) in the grand multiparas. The differences had no effect on neonatal outcome. Grand multiparity should be regarded as an obstetrical risk factor, mainly because of the higher frequency of placental complications. With good obstetric care there should be no adverse effects on the mother or the newborn.
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