USE OF SYNOGRAPHIC TECHNIQUES IN RESEARCH AND DISSEMINATION OF HYDROLOGICAL INFORMATION1

ABSTRACT: Application of synographic techniques to four separate nonrelated research tasks demonstrated the usefulness of such an approach in interpreting and communicating hydrologic survey data especially when large geographic areas are involved. Nutrient exchange and biotic indicators in coastal estuaries were analyzed to determine residence times in different seasons of the year. Man induced changes in urban runoff patterns were shown to increase the probability of flooding with different recurrences of storm events. Nitrate and indicator bacteria in private wells were analyzed on a county-wide basis to determine the sources and extent of natural occurrence versus contamination origins. Water wells and the surface supply of metropolitan Houston were analyzed for sodium content to assist citizens and physicians with data which are needed for derivation of sodium restricted therapeutic diets.     

Injury risk in behind armor blunt thoracic trauma.

First responders and military personnel are particularly susceptible to behind armor blunt thoracic trauma in occupational scenarios. The objective of this study was to develop an armored thorax injury risk criterion for short duration ballistic impacts. 9 cadavers and 2 anthropomorphic test dummies (AUSMAN and NIJ 0101.04 surrogate) were tested over a range of velocities encompassing low severity impacts, medium severity impacts, and high severity impacts based upon risk of sternal fracture. Thoracic injuries ranged from minor skin abrasions (abbreviated injury scale [AIS] 1) to severe sternal fractures (AIS 3+) and were well correlated with impact velocity and bone mineral density. 8 male cadavers were used in the injury risk criterion development. A 50% risk of AIS 3+ injury corresponded to a peak impact force of 24,900 +/- 1,400 N. The AUSMAN impact force correlated strongly with impact velocity. Recommendations to improve the biofidelity of the AUSMAN include implementing more realistic viscera and decreasing the skin thickness.     

Influence of flooding and vegetation on carbon, nitrogen, and phosphorus dynamics in the pore water of a Spartina alterniflora salt marsh

Four sites were selected in a salt marsh in the Bah′?a Blanca Estuary (Argentina): (1) low marsh (flooded by the tide twice daily) vegetated by S. alterniflora; (2) non-vegetated low marsh; (3) high marsh (flooded only in spring tides) vegetated by S. alterniflora; (4) non-vegetated high marsh. The pH and Eh were measured in sediments, while dissolved nutrients (ammonium, nitrate, nitrite and phosphate) and particulate organic matter (POM) were determined in pore water. pH (6.2–8.7) was only a ected by vegetation in low areas. Eh (from –300 to 250 mV) was lower at low sites than at high ones; in the latter, the values were higher in the non-vegetated sediments. The POM concentration was greater in the high marsh than in the low marsh, with no e ect of vegetation. Ammonium was the most abundant nitrogen nutrient species in pore water, except in the non-vegetated high marsh where nitrate concentration was higher. All nitrogen nutrients were a ected by both flooding and vegetation. Phosphate was always present in pore water at all sites throughout the year and its concentration varied within narrow limits, with no e ect of flooding and greater values always at non-vegetated sites. Our results showed that the variability of the pore water composition within the marsh is greater than the temporal variation, meaning that both tidal flooding and vegetation are important in the dynamics of nutrients and organic matter in the sediment pore water.     

Tree cover in sub-Saharan Africa: rainfall and fire constrain forest and savanna as alternative stable states

Savannas are known as ecosystems with tree cover below climate-defined equilibrium values. However, a predictive framework for understanding constraints on tree cover is lacking. We present (a) a spatially extensive analysis of tree cover and fire distribution in sub-Saharan Africa, and (b) a model, based on empirical results, demonstrating that savanna and forest may be alternative stable states in parts of Africa, with implications for understanding savanna distributions. Tree cover does not increase continuously with rainfall, but rather is constrained to low (<50%, "savanna") or high tree cover (>75%, "forest"). Intermediate tree cover rarely occurs. Fire, which prevents trees from establishing, differentiates high and low tree cover, especially in areas with rainfall between 1000 mm and 2000 mm. Fire is less important at low rainfall (<1000 mm), where rainfall limits tree cover, and at high rainfall (>2000 mm), where fire is rare. This pattern suggests that complex interactions between climate and disturbance produce emergent alternative states in tree cover. The relationship between tree cover and fire was incorporated into a dynamic model including grass, savanna tree saplings, and savanna trees. Only recruitment from sapling to adult tree varied depending on the amount of grass in the system. Based on our empirical analysis and previous work, fires spread only at tree cover of 40% or less, producing a sigmoidal fire probability distribution as a function of grass cover and therefore a sigmoidal sapling to tree recruitment function. This model demonstrates that, given relatively conservative and empirically supported assumptions about the establishment of trees in savannas, alternative stable states for the same set of environmental conditions (i.e., model parameters) are possible via a fire feedback mechanism. Integrating alternative stable state dynamics into models of biome distributions could improve our ability to predict changes in biome distributions and in carbon storage under climate and global change scenarios.     

Photoelectrocatalytic degradation of camphor on TiO2/RuO2 electrodes

The degradation of camphor using titanium/ruthenium dioxide (TiO₂/RuO₂; 70:30) electrodes was investigated in a photoelectrochemical thin-film reactor under near UV light irradiation. Two different electrolytes (Na₂SO₄ and NaCl) were used in this work. Camphor degradation was monitored by solvent extraction methods and gas chromatography (GC) analysis. Comparative studies between photoelectrochemical, electrochemical, photolytic, and heterogeneous photocatalytical process were carried out. When NaCl was used, the degradation efficiency of camphor was improved, probably on account of electrochemical generation of active chlorine species and their photochemical conversion to chlorine radicals. Under these conditions camphor was completely mineralized at reaction times of 30 min.     

Assessment of land influence on a high-latitude marine coastal system: Tierra del Fuego, southernmost Argentina

The study deals with the determination of physico-chemical parameters, inorganic nutrients, particulate organic matter, and photosynthetic pigments on a monthly basis during an annual cycle from nine sampling sites of the coastal zone of a high-latitude ecosystem (Tierra del Fuego, Argentina). Nitrites and phosphates concentrations were similar to other systems of the south Atlantic coast (median, 0.30 and 1.02 ??M, respectively), while nitrates were higher in all sampling periods (median, 45.37 ??M), and silicates were significantly smaller (median, 7.76 ??M). Chlorophyll a and phaeopigments have shown median values of 0.38 and 0.85 mg m^???3, respectively, while saturated values of dissolved oxygen were recorded throughout the study. The analysis reflected that nutrient enrichment seems to be linked to an anthropogenic source, the presence of peatlands areas, and a sink of Nothofagus pumilio woods. The area could be characterized in three zones related to (1) high urban influence, (2) natural inputs of freshwater, and (3) mixed inputs coming from moderate urban impacts.     

Estimating the effects of meteorology on PM2.5 reduction during the 2008 Summer Olympic Games in Beijing, China

Particulate pollution was a critical challenge to the promise of good air quality during the 2008 Beijing Olympic Games, which took place from August 8th to 24th. To ensure good air quality for the Games, several temporary emission control measures were implemented in Beijing and surrounding areas. Ambient particulate matter concentration decreased significantly during the Olympic period; however, it is difficult to distinguish the effectiveness of those control measures since meteorology also affects ambient PM_2.5 concentration. In this work, a multiple linear regression model based on continuous field monitoring at a roadside site was conducted to evaluate the effects of meteorology and emission control measures on the reduction of PM_2.5 during the 2008 Olympic Games. The hourly data set was divided into two time periods, the no control period, June 22nd to July 4th, and the control period, July 28th to August 21st. The response variable was PM_2.5 and the meteorology covariates used in the model were hourly temperature, dew point temperature, wind speed and precipitation. Wind direction was not a significant predictor of PM_2.5 levels in either the control or the no control period. Using the meteorologically-based regression coefficients from the two time periods, meteorology was found to contribute to at least a 16% reduction in PM_2.5 levels in the roadside microenvironment; while the pollution control measures contributed to at least a 43% reduction in PM_2.5 levels.     

Pharmaceuticals and personal care products’ (PPCPs) impact on enriched nitrifying cultures

Environmental Science and Pollution Research - The impact of pharmaceutical and personal care products (PPCPs) on the performance of biological wastewater treatment plants (WWTPs) has been widely...