Theoretical Study of the TiO2 and MgO Surface Acidity and the Adsorption of Acids and Bases

We present ab-initio periodic Hartree–Fock calculations (crystal program) of small molecules on TiO₂ and MgO. The adsorption of the molecules may be molecular or dissociative. This depends on their acid and basic properties in the gas phase. For the molecular adsorption, the molecules are adsorbed as bases on Ti(+IV) sites, the adsorption energies correlate with the proton affinities. The dissociations on the surface correlate with the gas phase cleavages: thus, the dissociation of MeOH leads to a preferential basic cleavage (the fragment HO– is adsorbed on a Ti⁺⁴ ion and the fragment Me⁺ is adsorbed on a O²– ion of the oxide). The opposite result is obtained with MeSH. Another important factor is the adsorbate–adsorbate interaction: favorable cases are a sequence of H-bonds for the hydroxyl groups resulting from the water dissociation and the mode of adsorption for the ammonium ions. Lateral interactions also force the adsorbed CO₂ molecules to bend over the surface so that their mutual orientation resembles the geometry of the CO₂ dimer. With respect to water adsorption, MgO appears to be a basic oxide. As experimentally observed, NH₃ adsorbs preferentially on TiO₂ and CO₂ on MgO. However, this difference of reactivity should not be expressed in terms of acid vs. basic behaviour but in terms of hard and soft acidity. The MgO surface is a 'soft' acidic surface that reacts preferentially with the soft base, CO₂.     

Visual pigments in a living fossil,the Australian lungfish <Emphasis Type="Italic">Neoceratodus forsteri</Emphasis>

Background  

One of the greatest challenges facing the early land vertebrates was the need to effectively interpret a terrestrial environment. Interpretation was based on ocular adaptations evolved for an aquatic environment millions of years earlier. The Australian lungfish Neoceratodus forsteri is thought to be the closest living relative to the first terrestrial vertebrate, and yet nothing is known about the visual pigments present in lungfish or the early tetrapods.     

Acute toxicity effects of ibuprofen on behaviour and haematological parameters of African catfish Clarias gariepinus (Burchell, 1822)

Indiscriminate discharge of pharmaceutical waste into the aquatic ecosystem may pose serious health challenges to aquatic biota. The effect of acute exposure to ibuprofen was evaluated using changes in behaviour and haematological parameters under static bio-assay method in Clarias gariepinus. Test specimens were exposed to acute concentrations of ibuprofen (0.28, 0.33, 0.38, 0.43 and 0.48 mg l^?1) for 24, 48, 72 and 96 h durations respectively. Behavioural and phenotypic changes were observed in surviving fish. There were significant (p < 0.05) concentration and duration-dependent increases in erythrocyte (RBC), haemoglobin (Hb), pack cell volume (PCV) and leukocytes (WBC) in treated fish compared to the control. Insignificant decreases (p > 0.05) in mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were observed in treated fish compared to the control. Ibuprofen elicited dose and duration- dependent decrease in neutrophil counts with the decreases being significant (p < 0.05) in the higher doses of 0.43 and 0.48 mg l^?1. Ibuprofen did not elicit any significant changes in monocytes, basophils and eosinophils. Changes observed in this study showed that ibuprofen negatively affected the health of the fish and we recommend that discharge of ibuprofen into the aquatic environment should be monitored and controlled.     

Minisatellite DNA profiling detects lineages and parentage in the endangered kakapo (Strigops habroptilus) despite low microsatellite DNA variation

An important goal of the conservationmanagement program of the critically endangeredground parrot, the New Zealand kakapo (Strigops habroptilus) is the determination ofparentage and levels of genetic diversitywithin the remaining population. Our previousmicrosatellite DNA studies have shown that allindividuals of this species except one arehomozygous at seven loci examined. Incontrast, we now show that a minisatellite DNAanalysis of kakapo provides sufficientvariation to conduct paternity analyses anddetect heterogeneity within the 86 livingkakapo. The sole remaining Fiordland kakapo,Richard Henry, is shown to be geneticallydivergent from individuals originating from theonly other remaining population on StewartIsland, suggesting that two lineages of kakapoare present in the extant population. This hasparticular significance for the conservationmanagement goal of maintenance of the maximumgenetic diversity in the species as a whole. The example of the kakapo illustrates thatminisatellite DNA markers can be useful incases where microsatellite DNA fails to showsufficient variation.     

Inheritance of resistance to the root-knot nematode Meloidogyne arenaria in Myrobalan plum

The inheritance of resistance of the self-incompatible Myrobalan plum Prunus cerasifera to the root-knot nematode Meloidogyne arenaria was studied using first a diallel cross between five parents of variable host suitability (including two highly resistant clones P.1079 and P.2175, a moderate host P.2032, a good host P.2646 and an excellent host P.16.5), followed by the G2 crosses P.16.5 × (P.2646 × P.1079) and P.2646 × (P.16.5 × P.1079). A total of 355 G1 and 72 G2 clones obtained from hard-wood cuttings sampled from trees in the field experimental design, then rooted in the nursery and inoculated individually in containers (5–10 replicates per clone) under greenhouse conditions, were evaluated for their host suitability based on a 0–5 gall-index rating under a high and durable inoculum pressure of the nematode. In the crosses involving the resistant P.1079 and P.2175 and the hosts P.2646 and P.16.5: (1) all of the G1 crosses of P.1079 were resistant while the G2 crosses segregated 1 resistant to 1 host, (2) the G1 crosses between P.2175 and either P.2646 or P.16.5 segregated 1 resistant to 1 host, and (3) all of the G1 progeny between P.2646 and P.16.5 were host. These results indicate that resistance is conferred by a single major dominant resistance gene (homozygous) in P.1079, and the same, or an allelic or a different, major dominant gene (heterozygous) in P.2175, and that P.2646 and P.16.5 are recessive for this (these) major resistance gene(s). As expected according to the hypothesis of a recessive genotype for P.2032, all of its hybrids with P.1079 were resistant, all of its hybrids with P.2646 and P.16.5 were host, and its hybrids with P.2175 segregated for resistance. Nevertheless, the 32 segregation ratio of these latter hybrids suggests that clones bearing the P.2175 gene would have a selective advantage. Both resistance genes are completely dominant and confer a non-host behaviour that totally prevents the multiplication of the nematode. This is the first reported evidence of major nematode resistance genes towards M. arenaria in a species of the subgenus Prunophora in the genus Prunus. The symbols Ma1 for the P.2175 gene and Ma2 for the P.1079 gene are proposed.     

Seasonal home ranges of elephants (Loxodonta africana) and their movements between Sabi Sand Reserve and Kruger National Park

We studied the seasonal home ranges and space use of three breeding herds of elephants (Loxodonta africana) for 3–5 years in an area comprising South Africa’s Sabi Sand Reserve (SSR) and Kruger National Park (KNP). Global Positioning System (GPS) transmitters were attached to the matriarchs of three herds and set to transmit a single daily location. Each herd was located in SSR 31%, 60% and 84% of the time. During the wet summer months, the herds walked longer distances and occupied larger seasonal home ranges than during the corresponding dry winter period. Core areas were centred on riverine habitats within both parks, with all three herds exhibiting closer distances to rivers and artificial water holes than would be expected if they were moving randomly. Home ranges within SSR overlapped much of the park. However, in KNP they occupied discrete areas with little overlap. Much of the movement between the two parks occurred along well‐defined corridors. This study shows that elephant herds depended upon the resources of both parks, providing an insight into their within‐ and between‐seasonal movements. This highlights the importance of ongoing co‐operation between wildlife managers from both parks when forming policy.     

RAPD and SCAR markers linked to the Ma1 root-knot nematode resistance gene in Myrobalan plum (Prunus cerasifera Ehr.)

 The Myrobalan plum (Prunus cerasifera) is a self-incompatible species in which the clones P.2175, P.1079 and P.2980 are highly resistant to all root-knot nematodes (RKN), Meloidogyne spp. Each clone bears a single major dominant gene, designated Ma1, Ma2 and Ma3 respectively, that controls a high and wide-spectrum resistance. Bulked segregant analysis (BSA) and random amplified polymorphic DNA (RAPD) analysis were both performed to detect markers linked to the Ma1 gene using three segregating progenies from P.2175 (Ma1 ma1) crossed by three host parents (ma1 ma1). Four dominant coupling-phase markers were identified from a total of 660 10-base primers tested. The resulting linkage map spans 14.7 cM and comprises three markers located on the same side of Ma1 and one marker located on the other side. The nearest markers (OPAL19₇₂₀ and OPA16₁₄₀₀) are located at 3.7 and 6.7 cM, respectively, on each side of the gene. Among the three markers that could be successfully converted into sequence characterized amplified region (SCAR) markers, two of them (SCAL19₆₉₀ and SCAN12₆₂₀) were scored as dominant markers whereas the third (SCAO19₇₇₀) failed to produce any polymorphism. SCAL19, and to a lesser extent SCAN12, can be used reliably in the marker-assisted selection of Prunus rootstocks. These markers are adequate to identify the Ma1 RKN resistance gene in intraspecific segregating progenies and will be suitable for the creation of interspecific rootstocks involving Myrobalan plum. Some of the RAPD and SCAR markers for Ma1 were also recovered in clones P.1079 and P.2980, but not in additional host clones, suggesting that Ma1, Ma2 and Ma3 are either allelic or at least closely linked. Received: 22 September 1998 / Accepted: 19 December 1998     

Designing Timber Harvesting to Enhance New Zealand Falcon Populations

Previous breeding-season studies of threatened New Zealand falcons (Falco novaeseelandiae) in plantation forests have suggested that falcons benefit when harvesting creates a mosaic of differently aged stands, especially where young and mature tree stands are adjacent. Thus, changes in the rate and pattern of harvesting may affect habitat heterogeneity by altering the size and distribution of forest patches. We sought to determine guidelines for harvesting that would most benefit falcons by increasing the carrying capacity of the forest for falcons. We used radio-tracking to determine the home-range sizes of non-breeding falcons over 3 seasons and compared winter home-range overlap in the most-selected land cover types by falcons (mature-young edges and open patches) with other land cover types. The distribution of open patches and edges between mature stands and recently cleared areas affected falcon home ranges, home-range overlap, and the likelihood of nesting. Specifically, home ranges were smaller as the density of edges and percentage of open patch increased, and there was greater home-range overlap between individuals in the most-selected land cover types. Numbers of falcons decreased as the size of open patches increased, concomitant with a decrease in edge size, the number of edge borders, and the number of open patches. The likelihood of nesting also decreased as open patch size increased. Our results indicate that smaller open patches spread through a forest, maximizing the amount of mature-young edges, will favor smaller home ranges and therefore potentially greater numbers of falcons. We recommend harvesting protocols that ensure that open patches (0–3-yr-old stands) are <4 km² in size and retain at least small stands of mature pine to maintain a high density of edges. Similar protocols may increase the carrying capacity for other species occurring in managed systems involving fragmented landscapes or small reserves. © 2021 The Wildlife Society.