Freedom and Responsibility: Reflections on Chapter II of Veritatis Splendor

In this chapter of the encyclical the Pope responds to the basic question of morality: How can obedience to universal and unchanging moral norms respect the uniqueness and individuality of the person and not represent a threat to his freedom and dignity? The Catholic vision of our relationship to God says that human freedom and growth is not in opposition to obedience to God and to the moral law, but that the two in fact presuppose one another. This is the heart of the vision of morality which Pope John Paul is asking the Church to live in our present age

Distribution of Hydrogen Peroxide In the Northwest Pacific Ocean

[1] Hydrogen peroxide (H2O2) is a reactive oxygen intermediate involved in the cycling of metals and dissolved organic matter. Because little is known of its distribution in the North Pacific Ocean, we determined H2O2 in surface waters continuously and obtained vertical profiles at nine stations during a cruise from Japan to Hawaii. Surface water H2O2 varied from less than 10 to more than 250 nmol dm(-3). A diel cycle in surface water H2O2 (similar to 25 nmol dm(-3)) was observed only on one day during the monthlong cruise. This is contrary to expectations based on the usual assumption of photo-production as the dominant input of H2O2. Experiments were also conducted during the cruise to examine both photo-production and dark decay. The net rate of photo-production at a station near Hawaii was determined to be 8 nmol dm(-3) h(-1), similar to rates reported for the central Atlantic Ocean and Antarctic. However, this maximum estimate of photo-production is also similar to probable rates of H2O2 input by other mechanisms ( biological production and rain). The pseudo-first-order rate constant for dark decay varied from 0.1 to 0.2 d(-1), which is toward the low end of previous reports of H2O2 decay rates, and was observed to increase proportionately to the dissolved organic carbon concentration. Taken together, these results suggest that photo-production of H2O2 in open ocean waters may be less important than previously thought and therefore H2O2 is likely less of an indicator of the photo-chemical reactivity of surface waters than hoped for. Furthermore, we observed that the H2O2 inventory for the upper 200 m of the water column has a maximum at midlatitudes. We suggest that this results from diminished inputs at high latitude as well as increased decay rates at low latitudes

The influence of solar ultraviolet radiation on the photochemical production of H2O2 in the equatorial Atlantic Ocean

Hydrogen peroxide (H2O2) was measured in marine surface waters of the eastern Atlantic Ocean between 25degreesN and 25degreesS. H2O2 concentrations decreased from 80 nM in the north to 20 nM in the south, in agreement with earlier observations. A diel cycle of H2O2 production as a function of sunlight in surface waters was followed twice whilst the ship steamed southward. Around 23degreesN a distinct diel cycle could be measured which correlated well with irradiance conditions. The wavelength dependency of H2O2 formation was studied near the equator. For 16 hours, water samples were incubated with wavelength hands of the solar spectrum, i.e. visible (VIS: 400-700 nm), VIS and ultraviolet A radiation (UVAR: 320-400 nm) and VIS, UVAR and ultraviolet B radiation (UVBR: 280-320 rim). A significant relationship was found between wavelength band and the production of H2O2. In addition, a clear positive relationship between intensity and production was found. UVAR was 6.5 times more efficient than VIS in producing 1 nM of H2O2, whereas UVBR was 228 times more efficient than VIS. When these data were weighted with respect to the energy of the solar spectrum at zenith hour, 28% of the H2O2 was formed by VIS, 23% was formed by UVAR and 48% was formed by UVBR. Considering the strong attenuation of UVBR in marine waters as compared with UVAR and VIS radiation, the role of UVAR deeper in the water column is recognised. Furthermore results of this research emphasise the importance of VIS radiation in the formation of H2O2