A mathematical comparison of classification structures: The case of the USDA Soil Taxonomy

Biologists have not paid much attention to the mathematical structures of biological classifications and their interpretations. A few have made such an analysis mainly using statistical distribution models. Comparisons with nonbiological classifications are needed to know if such structures are the result of biological evolution or of taxonomic practices, utilitarian bias, and/or subconscious cognitive rules. We compare the biological classification of a target group of soil borne plant parasitic nematodes (the Tylenchina suborder) with a non-biological one (the USDA 8th edition of the Keys to Soil Taxonomy). The authors made use of the same tools used in previous papers by biologists introducing other classifications. The results show that both taxonomies are information systems that try to optimize the information flow and fit well to the same distribution models. The analysis does not show any idiosyncrasies of biological classifications with respect to pedological ones, thus, supporting the idea that these products are the result of subconscious cognitive rules used by humankind to classify the world. Published in Russian in Pochvovedenie, 2006, No. 7, pp. 795–803. The text was submitted by the authors in English.     

Phenylphenalenone type compounds from the leaf fibers of abaca (Musa textilis)

A series of phenylphenalenone type compounds, known to play a role as phytoalexins in plants of the Musaceae family, have been identified for the first time in the leaf fibers of abaca (Musa textilis). Among the phenylphenalenone type compounds identified, the structure of a novel compound, (1R)-2,3-dihydro-4,9-dihydroxy-8-methoxy-1-phenylphenalene, has also been described in abaca fibers. Its structure was elucidated by analysis of one- and two-dimensional NMR (correlation spectroscopy, heteronuclear single quantum correlation, and heteronuclear multiple bond correlation) spectroscopic data.     

Photocatalytic Removal of the Antibiotic Cefotaxime on TiO<Subscript>2</Subscript> and ZnO Suspensions Under Simulated Sunlight Radiation

This study presents the main results about the removal of the antibiotic cefotaxime (CTX) under simulated sunlight radiation using heterogeneous photocatalysis with titanium dioxide (TiO₂) and zinc oxide (ZnO) in aqueous solutions. The effects of pH and catalyst initial load on pollutant removal were assessed considering the response surface methodology and a central composite circumscribed experimental design, which allowed to determine the optimized conditions that lead to a higher substrate elimination. Experimental results indicated that evaluated parameters have a significant effect on antibiotic removal in both TiO₂ and ZnO suspensions. In addition, the role of photogenerated holes, hydroxyl, and superoxide anion radicals on CTX degradation was evaluated to clarify the reaction mechanism. Finally, analysis of the dissolved organic carbon content in solutions and the antibacterial activity of treated samples showed that photocatalytic treatments were able to reduce a considerable portion of the organic matter present in the systems and its antimicrobial activity.     

Evolution of forest cover in Portugal: A review of the 12th–20th centuries

Portugal's forests in the 12th century were dominated by the Fagaceae represented by Quercus and Castanea, and several pine species.From the 12th century onwards, forests underwent changes in their management starting with protection and ultimately leading to intense exploitation. The massive naval construction during the maritime expansion(mainly in the 15th–16th centuries) involved felling of approximately 5 million trees mainly Quercus suber, Pinus pinea and other Quercus species. Cumulative fuel-wood consumption of 959 Mm3 during 1300–1854 was attributed to demographic expansion while the deforestation rate during 1636–1854 accounted for a minimum of 72.6% and a maximum of 96% of total forest cover. The volume of timber used in railway sleepers from 1856 onwards might have reached 0.5 Mm3. The last quarter of the 20th century increased the forest cover of Portugal through the World Bank program of Eucalyptus globulus reforestation.     

Hydraulic architecture and water relations of a flood-tolerant tropical tree, Annona glabra

Hydraulic architecture parameters, water relation parameters and wood anatomy were studied in roots and shoots of the flood-tolerant tree Annona glabra L. on Barro Colorado Island, Panama. Hydraulic conductivity, leaf specific conductivity, and Huber value were similar to the corresponding values for tree species living in non-flooded habitats. The vulnerability of stems to loss of hydraulic conductivity resulting from embolism was low (50% loss of conductivity at -3.3 MPa). The lowest leaf water potential measured in the field was about -1.0 MPa, indicating that A. glabra has a large margin of safety from embolism, which may provide protection against rare drought events, or may be an adaptation to brackish mangrove habitats. Low absolute conductivity of roots was compensated for by an increase in the number of roots. More than two-thirds of whole-plant resistance to water flow was located in the roots.     

RESPONSE OF FRIJOLILLO RHYNCHOSIA MINIMA (L) DC. TO SUPPLEMENTARY PHOSPHORUS WITH THREE SOIL MOISTURE CONDITIONS: II. SOLUTE ACCUMULATION

The objective of this study was to evaluate the effects of induced drought conditions and phosphorous (P) application on osmotic adjustment as reflected in the accumulation of organic solutes in the leaves of frijolillo. The experiment took place under greenhouse conditions without climate control. Plastic containers were used measuring 20 cm high × 15 cm in diameter. In each container, five plants were evaluated from emergence to vegetative growth phase. Three soil moisture regimes were evaluated (25%, 50%, and 100% of field capacity) combined with four concentrations of phosphorous (0, 50,100 and 150 mg kg^?1 of soil). A completely randomized block design with a factorial arrangement of 3×4 with four replications was used. The cellular osmotic adjustment as a response to drought stress in frijolillo was associated with the accumulation of sugars, amino acids and proline in that higher concentrations than the control were measured with moisture at 25%. Concentrations of chlorophyll and carotene increased as soil moisture levels decreased.     

Removal of Copper and Cadmium Ions from Diluted Aqueous Solutions by Low Cost and Waste Material Adsorbents

The sorption of copper and cadmium ions using activated carbon,kaolin, bentonite, diatomite and waste materials such as compost,cellulose pulp waste and anaerobic sludge as sorbents is reported. Equilibrium isotherms were obtained for the adsorption of these metals in single and binary solutions. Bentonite presented the highest adsorption capacities for both copper and cadmium. A competitive uptake was observed when both metals are present; copper being preferentially adsorbed by all materials with theexception of anaerobic sludge. Equilibrium data were fitted toLangmuir and Freundlich models, with satisfactory results for most of the adsorbent-metal systems studied.Of all the adsorbents studied, bentonite and compost presentedthe highest removal efficiencies, reaching 99% for copper whencadmium is also present, for initial solution concentrations ofup to 100 mg L^-1. Anaerobic sludge has a greater preferencefor cadmium, even in the presence of copper, with removal efficiencies of 98% for similar concentrations to those mentioned above.     

Chemical composition of the Lippia origanoides essential oils and their antigenotoxicity against bleomycin-induced DNA damage

The present work evaluated the chemical composition of the essential oils (EO) obtained from Lippia origanoides and their DNA protective effect against bleomycin-induced genotoxicity. L. origanoides EO chemical composition was determined by gas chromatography–mass spectrometry (GC–MS). The major compounds of the L. origanoides EOs were thymol (34–58%) and carvacrol (26%). The antigenotoxic effects of the EOs, major compounds and standard compound (epigallocatechin gallate) were assayed in co-incubation procedures using the SOS chromotest in Escherichia coli. Both EOs and their major compounds protected bacterial cells against bleomycin-induced genotoxicity indicating that these two compounds were principally responsible for the antigenotoxicity detected in the oils. Thymol and carvacrol antigenotoxicity was lower than those observed with epigallocatechin gallate. The results were discussed in relation to the chemopreventive potential of L. origanoides EOs and their major components, carvacrol and thymol.     

Effect of 4-amino-6-methyl-3-phenylamino-1,2,4-triazin-5(4H)-one on the integrity of chloroplasts from barley leaves

4-Amino-6-methyl-3-phenylamino-1,2,4-triazin-5(4H)-one alters the integrity of chloroplasts in barley (Hordeum vulgare L. var. Hassan) leaves as judged by their sedimentation profiles in linear gradients of sucrose. This effect may be related to the inhibition caused by 4-amino-6-methyl-3-phenylamino-1,2,4-triazine-5(4H)-one of both ascorbate peroxidase and superoxide dismutase activities, and could thus be explained by an accumulation of toxic reduced-oxygen species in illuminated chloroplasts.