Hypertensive Disorders of Pregnancy and Future Cardiovascular Health.

Hypertensive disorders of pregnancy (HDP) occur in almost 10% of gestations. These women are known to have higher cardiovascular morbidity and mortality later in life in comparison with parous controls who had normotensive pregnancies. Several studies have demonstrated that women with preeclampsia present in a state of segmental impaired myocardial function, biventricular chamber dysfunction, adverse biventricular remodeling, and hypertrophy, a compromised hemodynamic state and indirect echocardiographic signs of localized myocardial ischemia and fibrosis. These cardiac functional and geometric changes are known to have strong predictive value for cardiovascular disease in non-pregnant subjects. A "dose effect" response seems to regulate this relationship with severe HDP, early-onset HDP, coexistence of fetal growth disorders, and recurrence of HDP resulting in poorer cardiovascular measures. The mechanism underlying the relationship between HDP in younger women and cardiovascular disease later in life is unclear but could be explained by sharing of pre-pregnancy cardiovascular risk factors or due to a direct impact of HDP on the maternal cardiovascular system conferring a state of increased susceptibility to future metabolic or hemodynamic insults. If so, the prevention of HDP itself would become all the more urgent. Shortly after delivery, women who experienced HDP express an increased risk of classic cardiovascular risk factors such as essential hypertension, renal disease, abnormal lipid profile, and diabetes with higher frequency than controls. Within one or two decades after delivery, this group of women are more likely to experience premature cardiovascular events, such as symptomatic heart failure, myocardial ischemia, and cerebral vascular disease. Although there is general agreement that women who suffered from HDP should undertake early screening for cardiovascular risk factors in order to allow for appropriate prevention, the exact timing and modality of screening has not been standardized yet. Our findings suggest that prevention should start as early as possible after delivery by making the women aware of their increased cardiovascular risk and encouraging weight control, stop smoking, healthy diet, and daily exercise which are well-established and cost-effective prevention strategies

Scotch Pine: Variation and Performance in Minnesota

Scotch pine exhibits clinal variation from north to south in two characteristics: viz., the number of days after April 15 to the time of maximum rote of height growth, and total height after the age of 17 years. There is east-west clinal variation with respect to two characteristics: viz., the number of days after April 15 to the beginning of height growth, and to the time of the maximum rote of height growth. The twelve out of the fifteen varieties analyzed showed the existence of valid sub-varieties or ecotypes. Varieties from central Europe were the fastest growing in each of four planting sites in Minnesota. Significant mortality was noticed among the seed sources from the 40°-45° N. latitudinal class, in six outplantings. Production of lammas shoots was found to be under strong environmental influence. The seed sources from the 50°-55° N. zone were found to be the most highly susceptible to attack by the white pine weevil (Pissodes strobi Peck.)

The Changing Role of Non-CO2 Greenhouse Gases

During the last century, the concentrations of several greenhouse gases have increased considerably - most notably carbon dioxide, methane and nitrous oxide. In addition, new, entirely man-made gases have been put into the atmosphere that also cause the greenhouse effect; these include the chlorofluorocarbons. Calculations have shown that during the last century the non-CO₂ greenhouse gases could together be almost as effective as the increase of carbon dioxide in causing global warming. These and similar gases were therefore included in the Kyoto Protocol to develop a comprehensive plan for controlling potentially unfavorable climatic change. Studies show however that the other gases, with few exceptions, are likely to play a smaller than expected role in future global warming. The most significant non-CO₂ manmade greenhouse gases are methane and nitrous oxide. Methane rose from 700 ppbv some 200 years ago to about 1750 ppbv in recent times, while nitrous oxide rose from about 285 ppbv to 318 ppbv over the same time. These trends made methane the most important gas for global warming after carbon dioxide. But now, the rate of increase of methane has slowed down considerably. Budget analyses suggest that we may not see major changes of concentrations in the future comparable to the trends of the last century. Thus the role of methane in future global warming may be less than expected earlier. Nitrous oxide on the other hand, has increased slowly but steadily during recent decades. It is likely to become more important in the future compared with methane. While other greenhouse gases such as the perfluorocarbons, sulfur hexafluoride and hydrochlorofluorocarbons are included in the Kyoto Protocol, these are present in such minute concentrations that it is unlikely that they will have an important role in future global warming

Carbon monoxide in the antarctic atmosphere: Observations of decreasing concentrations

Hydroxyl radicals remove hundreds, perhaps thousands, of organic gases from the atmosphere and are often regarded as am index of the oxidizing capacity of the Earth\u27s atmosphere (Thompson 1992). In recent years, there have been growing concerns that, over the past century and now, human activities may be depleting hydroxyl concentrations by adding huge amounts of carbon monoxide and methane to the atmosphere. Reduction in the hydroxyl concentrations can then indirectly lead to more global warming, stratospheric ozone depletion, and other disturbances in atmospheric chemistry. Carbon monoxide (CO) is a key component in the determination of hydroxyl radical (OH) concentrations: increases of CO would lead to a decline of OH. Global increases of CO had been observed in the 1980s (Khalil and Rasmussen 1985, 1988, 1990), but now it appears that the atmospheric concentrations of CO are falling. Here we will report data from Antarctica that suggest recent decreases in the concentration of CO

Doubled CO2 Experiments With the Global Change Research Center Two-Dimensional Statistical Dynamical Climate Model

The zonally averaged response of the Global Change Research Center two-dimensional statistical dynamical climate model (GCRC 2-D SDCM) to a doubling of atmospheric carbon dioxide (350 parts per million by volume (ppmv) to 700 ppmv) is reported. The model solves the two-dimensional primitive equations in finite difference form (mass continuity, Newton\u27s second law, and the first law of thermodynamics) for the prognostic variables: zonal mean density, zonal mean zonal velocity, zonal mean meridional velocity, and zonal mean temperature on a grid that has 18 nodes in latitude and 9 vertical nodes (plus the surface). The equation of state, p=rhoRT, and an assumed hydrostatic atmosphere, Deltap=rhogDeltaz, are used to diagnostically calculate the zonal mean pressure and vertical velocity for each grid node, and the moisture balance equation is used to estimate the precipitation rate. The model includes seasonal variations in solar intensity, including the effects of eccentricity, and has observed land and ocean fractions set for each zone. Seasonally varying values of cloud amounts, relative humidity profiles, ozone, and sea ice are all prescribed in the model. Equator to pole ocean heat transport is simulated in the model by turbulent diffusion

New Study Of Electrical Conductivity In Ni-Doped Non -Stoichiometric Lithium Tantalite

Electrical conductivity in Ni-doped nonstoichiometric lithium tantalite was described by a new theoretical approach. From the experience, we have proposed the new vacancy models which are able to describe substitutional mechanism in Ni-doped lithium tantalite. A combinaison of phase transition theory and generalised vacancy models allows us to establish a new expression of electrical conductivity which takes into account the defect structure of Ni-doped lithium tantalate. Calculations of the conductivity in Ni-doped nonstoichiometric lithium tantalate reveal good correspondence with experimental results.Electrical conductivity in Ni-doped nonstoichiometric lithium tantalite was described by a new theoretical approach. From the experience, we have proposed the new vacancy models which are able to describe substitutional mechanism in Ni-doped lithium tantalite. A combinaison of phase transition theory and generalised vacancy models allows us to establish a new expression of electrical conductivity which takes into account the defect structure of Ni-doped lithium tantalate. Calculations of the conductivity in Ni-doped nonstoichiometric lithium tantalate reveal good correspondence with experimental results