UV photoreduction of aqueous nitrite in heptane suspensions

Ultraviolet photolysis of aqueous nitrite solutions in contact with a paraffin hydrocarbon causes a reduction of nitrite, by abstracted hydrogen atoms, to occur. This is evidenced by the formation of ammonium whose concentration is found to follow a simple, overall, kinetic pattern.     

Photoreactivity of some organics with aqueous Br− and I− codissolved with nitrate

Our earlier research on the photochlorination of some organics suspended in solutions of aqueous Cl^? codissolved with anionic NO _x ^? is extended to systems comprising either bromides or iodides, and NO ₃ ^? . It is found that the bromide-containing systems follow, under both artificial UV and sunlight, overall reaction patterns quite similar to those of chlorides although the rate term which stands for the bromination of organics is larger and directly proportional to light intensities. Solutions containing iodides also follow a similar overall pattern but the first rate term is now proportional to the square of light intensity. However, they react liberating detectable amounts of iodine which thereafter attack the hydrocarbon. This excess of elementary iodine is thus found to be either dissolved in or adsorbed by the organic; it furthermore also dissolves and becomes complexed in the aqueous phase.     

Photochlorination of organics by aqueous Cl− codissolved with anionic NO x Emphasis>/−

The dissipation of chemical elements from ash basin effluent was determined by use of neutron activation analysis of sediment, water, plant, invertebrate, and vertebrate samples taken from successive sites through the drainage system. Samples were tested for concentrations of 40 elements for a 12 mo period. Three different modes of dissipation were found. The major mechanism for removal of chemical elements from effluent was sedimentation into the benthic sediment. All biota had greater concentrations of chemicals than did water, with invertebrates having slightly higher levels than did plants and vertebrates. Ten elements were more concentrated in at least one biotic group than in the sediment. Concentrations of six elements in the drainage system exceeded the EPA recommended limits for surface waters. The observed modes of dissipation in this aquatic system emphasize the necessity for stable biotic communities present to permit cycling of chemical elements.     

Photocatalytic fixation of nitrogen by aqueous suspensions of silver iodide

The photodecomposition of AgI is but one of the many transformations which natural, anthropogenic and artificial aerosols undergo under light. Our aim here is to show that UV photolysis of AgI is accompanied by the fixation of N₂, whether it occurs in an atmosphere of that gas or in air.     

Photoreactivity of aqueous anionic NOx - with hydrocarbons

Research on ammonium formation, by photoreduction under UV radiation of aqueous nitrite with suspended heptane, is extended to benzene and terpin hydrate. Radiation intensities similar to those found in nature are used this time with the purpose of determining, under laboratory conditions, overall rates of those processes. The photolysis is carried out in a versatile apparatus and the results obtained are regarded as introductory towards investigations to be carried out under conditions of sunlight illumination. While the formation of ammonium in the nitrite — heptane system is found to follow the pattern previously outlined, thus confirming our earlier work, the reaction with both compounds which contain either double bonds or OH groups follows a simpler route which involves much larger yields of ammonium, and an attack of photoformed transients onto those reactive sites.     

Mammary carcinoma in a tiger (Panthera tigris): morphological and immunohistochemical study

The histologic and immunohistochemical features of a case of mammary gland carcinoma are described in a 14-yr-old female tiger (Panthera tigris). Immunoreactivity to estrogen receptor (ER), progesterone receptor (PR), tumoral protein 53 (p53), vascular endothelial growth factor (VEGF), human epidermal growth factor receptor 2 (HER-2), and cyclooxigenase-2 (COX-2) was investigated. Neoplastic cells were negative for ER, PR, and p53 but showed positivity for VEGF, HER-2, and COX-2, both in the primary and the metastatic lesions. Histopathologic findings and immunohistochemistry results suggested that the malignant behavior of the reported case could be comparable with some aggressive cat mammary carcinomas.     

Sportfisheries,conservation and sustainable livelihoods: a multidisciplinary guide to developing best practice

Ecotourism ventures in developing countries are often among the few alternatives for enhancing sustainable livelihoods without altering traditional ways of life. The best way forward is to continually develop and implement best practice guidelines and, in particular, to flexibly develop them to suit individual cases. We conduct a multidisciplinary assessment of best practice guidelines required to develop and sustain sportfishing tourism in developing countries, while enhancing local livelihoods and promoting environmental stewardship. In general, best practice guidelines should be developed around a sustainable livelihood framework that includes short‐term coping mechanisms and longer‐term capacity building. Sportfishing development that conforms to ecological and socially orientated criteria, founded on site‐specific research that captures local environmental and social complexities, has the potential to provide mutual benefits to tourists and local people, fuelling community development and enhancing the cultural experience of tourists. Best practice guidelines for sportfishing that do not address these dimensions are unlikely to result in a viable industry. Given the current interest and growth of sportfishing in developing countries, the proposed guidelines can help a range of end users manage, conserve and maximize livelihood benefits from their fishery.     

On routine colorimetric determination of trace nitrates,by brucine,in the presence of chloride

A colorimetric method was developed for the determination of trace nitrates in solutions containing up to 50 g 1^?1 of sodium chloride. Beer's law applies, in such solutions for concentrations of up to 1 mg of NaNO₃ per liter. Effects of sodium chloride concentration and time on the development of color were quantitatively evaluated with an overall error of about 4%. Temperature effects on solutions analyzed were found to be a major cause of inconsistencies in this otherwise satisfactory method.     

Photoreactivity of aqueous anionic nox − with hydrocarbons

The reduction of aqueous nitrates by suspended N-heptane is investigated under irradiation with a strong unfiltered UV source. Chemical changes are monitored using time-curves of nitrite and ammonium formation in the aqueous phase. Those kinetics suggest overall reactions which involve free radicals and take place over a wide range of NO concentrations, temperatures, pH and light intensity. The research is aimed at a better understanding of some photoprocesses which occur on heterogeneous aerosol substance, in areas polluted by either natural or man-made particulates.     

Photoreactivity of aqueous anionic NOx with hydrocarbons part I nitrite-heptane system under strong UV. radiation

The reduction of nitrous ions, in solutions containing heptane suspended under vigorous stirring and irradiated with a strong UV source, is investigated. The formation of ammonium is used as a monitor of the process which also leads to the concurrent production of organic nitrates and nitrites, as well as of aldehydes and nitro, nitroso and ammino derivatives. An overall mechanism of ammonium formation and destruction is proposed and tested and the effects of NO _inf2 ^sup? concentration, pH, radiation intensity and temperature are evaluated. Implications towards the importance of similar reactions which may occur under sunlight are discussed.