Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Species data deficiency

Descriptive taxonomy might be able to further influence conservation by aiding in the issue of reclassifying Data Deficient (DD) species on the Red List. The DD category is applied to a species when the available information is not sufficient for a full assessment of conservation status to be made, hi reality, there are three reasons why a species might be classifled as DD ... [Pg.36]

In spite of well identified deficiencies, the status of the existing thermodynamic data on solid halides and related compounds is rather satisfactory. By contrast, the data on aqueous halogeno-complexes are fragmentary, sometimes contradictory and in most cases limited to stability constants in such a context, recommendation of best values can be made for a few species only. [Pg.97]

It should be emphasized that very little is quantitatively known about how the total pressures of plutonium-bearing species vary with oxygen potential, stoichiometry, and temperature in the bivariant region of oxygen-deficient plutonia between the phase limits at very high temperatures. New (though limited) oxygen potential data have been obtained in our laboratory above the fluorite, diphasic, and sesquioxide phases in the Pu-0 system at 1750, 2050, and 2250 K. [Pg.113]

Anand et al. 1987). The authors hypothesized that the ocular effects associated with endosulfan may be a result of prolonged hypertension (although no data on blood pressure were presented, and there is no other information to indicate that chronically administered endosulfan induces hypertension) or an endosulfan-induced vitamin A deficiency (which was observed in this study). Although the rabbit may represent a uniquely sensitive species, the possibility that long-term exposure of persons at hazardous waste sites to endosulfan may result in adverse effects on ocular tissues cannot be eliminated. [Pg.155]

Apparently similar flowstream universal buffers have been developed by Alibrandi and others [128,129] for assessing kinetic parameters, such as the pH-dependent hydrolysis of acetylsalicylic acid. The pH-time curves are not as linear as in the SGA system. Other reports of continuous flow pH gradient spectrophotometric data have been described, with application to rank-deficient resolution of solution species, where the number of components detected by rank analysis is lower than the real number of components of the system [130]. The linear pH-time gradient was established in the flowstream containing 25 mM H3PO4 by the continuous addition of 100 mM Na3P04. [Pg.32]

It is generally believed that it was Ingold [1] in the early 1930s who proposed the first global electrophilicity scale to describe electron-deficient (electrophile) and electron-rich (nucleophile) species based on the valence electron theory of Lewis. Much has been accomplished since then. One of the widely used electrophilicity scales derived from experimental data was proposed by Mayr et al. [5-12] ... [Pg.179]

The uncertainties fall into two broad categories. Firstly, there are the uncertainties related to the extrapolation of the key data from experimental animal species to the average human (animal-to-human), and then from the average human to other members of the population with different characteristics (human-to-human), i.e., those with greater sensitivity. Secondly, there are then a number of uncertainties related to the available database including those arising from route-to route extrapolation, duration of exposure, NOAEL not established or not firmly established, and gaps or other deficiencies in the database. [Pg.223]

Renwick et al. (2000) have performed an analysis of the need for an additional UF for infants and children. They considered that the proposal to introduce an additional 10-fold factor when exposure of infants and children is anticipated implies either age-related differences between species or differences within humans, which exceed those present in adults. Alternatively, the extra factor could be related to deficiencies of current testing methods or concerns over irreversibility in developing organ systems. They concluded that the available data did not provide a scientific rationale for an extra factor due to inadequacy of inter- and intraspecies UFs. Justification for the factor therefore must relate to the adequacy and sensitivity of current methods or concern about irreversible effects in the developing organism. They also pointed out that when adequate reproduction, multigeneration, or developmental studies are conducted, there will be no need for an additional 10-fold factor. [Pg.226]

Analytical Chemical Data for Natural Waters. While elemental compositions of various natural waters usually can be determined with good reliability, analytical methods to distinguish between free and complex-bound species, oxidized and reduced forms, simple and polynuclear metal ion forms, and even between dissolved and colloidal or suspended phases are often lacking. Data on the nature and amounts of the individual substances which make up the total concentrations of organic material found in different natural waters are not yet extensive. These analytical deficiencies relate almost solely to the highly reactive, non-conservative elements—e.g., iron, manganese, phosphorus, carbon, nitrogen, aluminum, and other metal ions. [Pg.17]


See other pages where Species data deficiency is mentioned: [Pg.275]    [Pg.34]    [Pg.524]    [Pg.366]    [Pg.123]    [Pg.183]    [Pg.120]    [Pg.54]    [Pg.232]    [Pg.138]    [Pg.147]    [Pg.180]    [Pg.1220]    [Pg.55]    [Pg.208]    [Pg.552]    [Pg.1564]    [Pg.1582]    [Pg.253]    [Pg.184]    [Pg.256]    [Pg.224]    [Pg.119]    [Pg.548]    [Pg.131]    [Pg.228]    [Pg.985]    [Pg.208]    [Pg.552]    [Pg.1610]    [Pg.1628]    [Pg.103]    [Pg.289]    [Pg.366]    [Pg.137]    [Pg.123]    [Pg.126]    [Pg.155]    [Pg.763]   


SEARCH



Species data

© 2024 chempedia.info