bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of a varied assemblage of seed dispersers of a fleshy‐fruited plant
Authors: Calviño-Cancela María , Martín-Herrero Julio
Published: December 2009

Disperser effectiveness is the number of new plants resulting from the activity of one disperser relative to other dispersers or to nondispersed seeds. Effectiveness remains largely uninvestigated due to the complexity of its measurement. We measured the effectiveness of seed dispersers (Larus michahellis, Turdus merula, and Oryctolagus cuniculus) of the shrub Corema album (Empetraceae) using a simulation model of the recruitment process that was parameterized with field data of seed dispersal, predation, and seedling emergence and validated with independent data on seedling density. The model allows tracking the fate of seeds dispersed by each animal and estimating, for the first time, disperser effectiveness as seedlings per square meter contributed by each disperser. It also allows quantifying the relative importance of different recruitment processes in determining the quantity and spatial distribution of recruitment.

Larus michahellis was the most effective disperser in two of the three habitats studied, contributing 3–125 times more than the other two species, whose lower effectiveness depended mostly on deposition patterns (T. merula) or deleterious effects on seedling emergence (O. cuniculus). The dependence of the plant on each disperser differed between habitats and was the greatest in sparse scrub, where recruitment depended almost exclusively on gulls (90%). Quantity and quality of dispersal were not correlated; quality was a better predictor of disperser effectiveness. Seedling emergence was the most crucial process in determining both the spatial pattern of recruitment among microhabitats (99.8% of variance explained) and the quantity of recruitment within microhabitats (43–83%). A sensitivity analysis showed that increasing seed dispersal improved the recruitment for all dispersers when there was no competition for fruits. However, with limited fruits, increased dispersal of lower quality dispersers reduced overall recruitment.

Our results show important differences in effectiveness among dispersers and illustrate the different influences of the components of effectiveness, which varied depending not only on the disperser but also on the circumstances (e.g., type of habitat).
Turning inducible defenses on and off: adaptive responses of Daphnia to a gape‐limited predator
Authors: Riessen Howard P. , Trevett-Smith Julie B.
Published: December 2009

The use of inducible defenses is a common strategy to reduce predation while minimizing associated costs for prey. The most effective use of these defenses, however, may involve turning them on and off at different stages of ontogenetic development, with the timing dependent on prey body size and the nature of the predation environment. We develop a model based on the strike efficiency of a size‐selective predator that examines the interaction between induced morphological defenses and prey body size, including the consequences of this interaction for the optimal development of the defenses during the prey's ontogeny. We then examine this model with respect to a model system of inducible defenses: neck spine induction in the water flea Daphnia in response to predatory larvae of the phantom midge Chaoborus.

In accordance with predictions of the model, the body size and timing of neck spine acquisition during Daphnia development are related to the relative sizes of the Daphnia and Chaoborus species interacting in a pond or lake. The Daphnia species examined first acquire neck spines in either the first, second, or third juvenile instar, at body lengths that range from 0.58 to 0.83 mm. Neck spine formation is initiated at larger Daphnia body sizes when these prey are subject to predation by a larger Chaoborus species (C. trivittatus) and at smaller sizes when exposed only to a smaller predator (C. americanus). Induction of these morphological defenses in Daphnia occurs later in juvenile development in the smaller of the two species we examined (D. minnehaha) than in the larger (D. pulex). Delayed acquisition of neck spines also occurs when Daphnia are exposed to predation by larger Chaoborus. The close match between model predictions and the patterns observed in nature suggests that these patterns are adaptive developmental responses to different predator environments.
Stable isotope fingerprinting: a novel method for identifying plant, fungal, or bacterial origins of amino acids
Authors: Larsen Thomas , Taylor D. Lee , Leigh Mary Beth , O'Brien Diane M.
Published: December 2009

Amino acids play an important role in ecology as essential nutrients for animals and as currencies in symbiotic associations. Here we present a new approach to tracing the origins of amino acids by identifying unique patterns of carbon isotope signatures generated by amino acid synthesis in plants, fungi, and bacteria (“13C fingerprints”). We measured amino acid δ13C from 10 C3 plants, 13 fungi, and 10 bacteria collected and isolated from a boreal forest in interior Alaska, USA, using gas chromatography‐combustion‐isotope ratio mass spectrometry (GC‐C‐IRMS). Microorganisms were cultured under amino‐acid‐free conditions and identified based on DNA sequences. Bacteria, fungi, and plants generated consistent, unique 13C fingerprints based on the more complex amino acids (five or more biosynthetic steps) that are classified as essential for animals. Linear discriminant analysis classified all samples correctly with >99% certainty and correctly classified nearly all insect samples from a previous study by diet. Our results suggest that 13C fingerprints of amino acids could provide a powerful in situ assay of the biosynthetic sources of amino acids and a potential new tool for understanding nutritional linkages in food webs.
Transmission dynamics of Tasmanian devil facial tumor disease may lead to disease‐induced extinction
Authors: McCallum Hamish , Jones Menna , Hawkins Clare , Hamede Rodrigo , Lachish Shelly , Sinn David L. , Beeton Nick , Lazenby Billie
Published: December 2009

Most pathogens threatening to cause extinction of a host species are maintained on one or more reservoir hosts, in addition to the species that is threatened by disease. Further, most conventional host–pathogen theory assumes that transmission is related to host density, and therefore a pathogen should become extinct before its sole host. Tasmanian devil facial tumor disease is a recently emerged infectious cancer that has led to massive population declines and grave concerns for the future persistence of this largest surviving marsupial carnivore. Here we report the results of mark–recapture studies at six sites and use these data to estimate epidemiological parameters critical to both accurately assessing the risk of extinction from this disease and effectively managing this disease threat. Three sites were monitored from before or close to the time of disease arrival, and at three others disease was well established when trapping began, in one site for at least 10 years. We found no evidence for sex‐specific differences in disease prevalence and little evidence of consistent seasonal variation in the force of infection. At all sites, the disease was maintained at high levels of prevalence (>50% in 2–3‐year‐old animals), despite causing major population declines. We also provide the first estimates of the basic reproductive rateR0for this disease. Using a simple age‐structured deterministic model, we show that our results are not consistent with transmission being proportional to the density of infected hosts but are consistent with frequency‐dependent transmission. This conclusion is further supported by the observation that local disease prevalence in 2–3‐year‐olds still exceeds 50% at a site where population density has been reduced by up to 90% in the past 12 years. These findings lend considerable weight to concerns that this host‐specific pathogen will cause the extinction of the Tasmanian devil. Our study highlights the importance of rapidly implementing monitoring programs to determine how transmission depends on host density and emphasizes the need for ongoing management strategies involving a disease‐free “insurance population,” along with ongoing field monitoring programs to confirm whether local population extinction occurs.
Trade‐offs between predation risk and forage differ between migrant strategies in a migratory ungulate
Authors: Hebblewhite Mark , Merrill Evelyn H.
Published: December 2009

Trade‐offs between predation risk and forage fundamentally drive resource selection by animals. Among migratory ungulates, trade‐offs can occur at large spatial scales through migration, which allows an “escape” from predation, but trade‐offs can also occur at finer spatial scales. Previous authors suggest that ungulates will avoid predation risk at the largest scale, although few studies have examined multi‐scale trade‐offs to test for the relative benefits of risk avoidance across scales. Building on previously developed spatial models of forage and wolf predation risk, we tested for trade‐offs at the broad landscape scale and at a finer, within‐home‐range scale for migratory and non‐migratory resident elk (Cervus elaphus) during summer in the Canadian Rockies in Banff National Park (BNP) and adjacent Alberta, Canada. Migration reduced exposure to wolf predation risk by 70% relative to residents at the landscape scale; at the fine scale, migrants used areas that were, on average, 6% higher in forage digestibility. In contrast, by forgoing migration, resident elk were exposed to higher predation risk, but they reduced predation risk at fine scales to only 15% higher than migrants by using areas close to human activity, which wolves avoided. Thus, residents paid for trying to avoid predation risk with lower forage quality. Residents may have been able to compensate, however, by using areas of abundant forage close to human activity where they may have been able to forage more selectively while avoiding predation risk. Human activity effectively decoupled the positive correlation between high forage quality and wolf predation, providing an effective alternate strategy for residents, similar to recent findings in other systems. Although ungulates appear capable of balancing risk and forage at different spatial scales, risk avoidance at large landscape scales may be more effective in the absence of human‐caused refugia from predation.
Weak effect of climate variability on coexistence in a sagebrush steppe community
Authors: Adler Peter B. , HilleRisLambers Janneke , Levine Jonathan M.
Published: December 2009

Climate variability, which is expected to increase in the future, can promote coexistence through a mechanism called the storage effect. Currently, we have little understanding of how the importance of the storage effect varies among ecosystems. We tested for the three conditions of the storage effect in a sagebrush steppe plant community in Idaho (USA) by combining long‐term observational data with statistical models. The four sagebrush steppe species that we studied satisfied the first two conditions of the storage effect: a long‐lived life stage and species‐specific responses to the environment. But the critical third condition, environment‐competition covariance, was very weak in this community. While the direction of the covariance was consistent with a stabilizing effect of variability (stronger competition in more favorable years), its magnitude was small, reflecting low temporal variability in both competition and species responses to the environment. Consistent with this result, simulations of species population growth rates when rare showed that climate variability had no consistent stabilizing effect on coexistence. This case study provides an important reminder that species‐specific responses to the environment are not sufficient for coexistence via the storage effect. Instead, the magnitude of temporal variability in species performance also plays an important role. Comparison of our results with those from a similar study in Kansas mixed prairie suggests that temporal variability in species performance may reflect both the strength of environmental variability as well as life history strategies.
Controls over leaf litter decomposition in wet tropical forests
Authors: Wieder William R. , Cleveland Cory C. , Townsend Alan R.
Published: December 2009

Tropical forests play a substantial role in the global carbon (C) cycle and are projected to experience significant changes in climate, highlighting the importance of understanding the factors that control organic matter decomposition in this biome. In the tropics, high temperature and rainfall lead to some of the highest rates of litter decomposition on earth, and given the near‐optimal abiotic conditions, litter quality likely exerts disproportionate control over litter decomposition. Yet interactions between litter quality and abiotic variables, most notably precipitation, remain poorly resolved, especially for the wetter end of the tropical forest biome. We assessed the importance of variation in litter chemistry and precipitation in a lowland tropical rain forest in southwest Costa Rica that receives >5000 mm of precipitation per year, using litter from 11 different canopy tree species in conjunction with a throughfall manipulation experiment. In general, despite the exceptionally high rainfall in this forest, simulated throughfall reductions consistently suppressed rates of litter decomposition. Overall, variation between species was greater than that induced by manipulating throughfall and was best explained by initial litter solubility and lignin:P ratios. Collectively, these results support a model of litter decomposition in which mass loss rates are positively correlated with rainfall up to very high rates of mean annual precipitation and highlight the importance of phosphorus availability in controlling microbial processes in many lowland tropical forests.
Plant species richness and functional composition drive overyielding in a six‐year grassland experiment
Authors: Marquard Elisabeth , Weigelt Alexandra , Temperton Vicky M. , Roscher Christiane , Schumacher Jens , Buchmann Nina , Fischer Markus , Weisser Wolfgang W. , Schmid Bernhard
Published: December 2009

Plant diversity has been shown to increase community biomass in experimental communities, but the mechanisms resulting in such positive biodiversity effects have remained largely unknown. We used a large‐scale six‐year biodiversity experiment near Jena, Germany, to examine how aboveground community biomass in grasslands is affected by different components of plant diversity and thereby infer the mechanisms that may underlie positive biodiversity effects. As components of diversity we defined the number of species (1–16), number of functional groups (1–4), presence of functional groups (legumes, tall herbs, small herbs, and grasses) and proportional abundance of functional groups. Using linear models, replacement series on the level of functional groups, and additive partitioning on the level of species, we explored whether the observed biodiversity effects originated from disproportionate effects of single functional groups or species or from positive interactions between them.

Aboveground community biomass was positively related to the number of species measured across functional groups as well as to the number of functional groups measured across different levels of species richness. Furthermore, increasing the number of species within functional groups increased aboveground community biomass, indicating that species within functional groups were not redundant with respect to biomass production. A positive relationship between the number of functional groups and aboveground community biomass within a particular level of species richness suggested that complementarity was larger between species belonging to different rather than to the same functional groups. The presence of legumes or tall herbs had a strong positive impact on aboveground community biomass whereas the presence of small herbs or grasses had on average no significant effect. Two‐ and three‐way interactions between functional group presences were weak, suggesting that their main effects were largely additive. Replacement series analyses on the level of functional groups revealed strong transgressive overyielding and relative yields >1, indicating facilitation. On the species level, we found strong complementarity effects that increased over time while selection effects due to disproportionate contributions of particular species decreased over time. We conclude that transgressive overyielding between functional groups and species richness effects within functional groups caused the positive biodiversity effects on aboveground community biomass in our experiment.
Gross vs. net income: How plant toughness affects performance of an insect herbivore
Authors: Clissold Fiona J. , Sanson Gordon D. , Read Jenny , Simpson Stephen J.
Published: December 2009

Leaf biomechanical properties are thought to impose a significant obstacle to herbivores and as such influence patterns of herbivory more than leaf chemistry. However, evidence for the role of structural traits in influencing herbivore food choice and performance has come from correlative studies, whereas the underlying mechanisms have been given little attention. By manipulating the biomechanical properties of a host grass species through a combination of lyophilization and milling, and providing water separately, we were able to compare behavioral, physiological, and developmental responses of the Australian plague locust, Chortoicetes terminifera, to the biomechanical properties of plant food (exemplified by toughness) independently of the food's macronutrient content and the insect's demand for water. Increasing leaf toughness was associated with reduced rates of locust growth and prolonged development, with potential ecological consequences. Poorer performance on the tougher foods was primarily a consequence of a reduced rate of nutrient supply, which occurred as a result of (1) smaller meals being eaten more slowly, (2) slowed gut passage rates, which limited how quickly the next meal could be taken, and (3) reduced efficiency of assimilation of nutrients from food in the gut. In addition, there were deleterious changes in the ratio of protein to carbohydrate assimilated from the gut. Prolonged development time was associated with increased total nutrient demands throughout the extended developmental period. Because these demands could not be met by increased consumption, there was a decreased efficiency of conversion of assimilated nutrients to growth. By disentangling the effects of biomechanical properties from macronutrient and water content we have shown that leaf biomechanical traits can influence chewing herbivores independently of leaf chemical traits.
Community niche predicts the functioning of denitrifying bacterial assemblages
Authors: Salles Joana F. , Poly Franck , Schmid Bernhard , Roux Xavier Le
Published: December 2009

Predicting biodiversity effects on ecosystem functioning requires adequate evaluation of the mechanisms explaining why more diverse systems could perform better than less diverse ones. In this context, tackling functional diversity has become an important issue. Even though the aggregation of species into functional groups supposes niche differences among groups, the concept of niche has not been fully exploited in the context of the biodiversity–ecosystem functioning research. Here we report the results of microcosm experiments where we used bacteria as a model to explore whether niche differences among species provide a good estimation of community functioning. For that we used experimental communities of denitrifying bacterial species and investigated the effects of bacterial diversity on two community processes, denitrification and anaerobic CO2‐production. We first measured the activities of 16 bacterial species grown individually on six different carbon sources. We then used the same set of species to assemble communities varying in both species richness and composition in microcosms containing a mixture of all six carbon sources. The performances of individual species on individual carbon sources were used to calculate, for each process measured, an a priori index called “community niche” that accounted for the performances of the species present in a given community across the entire range of the six resources. We found that species richness had a positive but small effect on both community processes whereas community niche explained a much larger proportion of the variation. According to the results of a path analysis, community niche was the main driver for the corresponding community process, but species richness affected community niche and thus had an indirect effect on denitrification and CO2 production. In addition to community niche, the presence of particular bacterial species also influenced community functioning, indicating that other effects than the capacity to use carbon sources played a, albeit minor, role in our experiment. Our study provides evidence for the importance of resource niches in shaping biodiversity–ecosystem functioning relationships of bacterial communities.
Multi‐decade, spatially explicit population studies of canopy dynamics in Michigan old‐growth forests
Authors: Woods Kerry D.
Published: December 2009

Established in 1935, a regular grid of 256 permanent plots includes about 20% of a 100‐ha old‐growth forest at the Dukes Research Natural Area in northern Michigan, USA. Woody stems have been re‐measured 3–7 times providing extensive quantitative records of population and community dynamics over periods of up to 72 years. Woody stems in upland hemlock–northern hardwood stands, about half of the study plots, have been mapped and individually tracked since about 1990. Remaining plots are in swampy stands dominated by Fraxinus nigra and Thuja occidentalis. Detailed, long‐term demographic data for late‐successional forests are rare in general; this data set is both of exceptional duration and unusual in spatial intensity and detail. Because sample plots are in a regular array over the stand, they can support analyses of spatiotemporal pattern at various scales. A major wind disturbance in 2002 provides a unique opportunity to compare disturbance response to baseline dynamics. Several publications based on this data set have already provided new insights into late‐successional processes, but general availability of the data set with metadata should permit a range of further comparative and integrative analyses. The study is ongoing, and new measurements will be added to the archived data set.

The complete data sets corresponding to abstracts published in the Data Papers section of the journal are published electronically in Ecological Archives at 〈http://esapubs.org/archive〉. (The accession number for each Data Paper is given directly beneath the title.)
The growing stock of the Republic of Serbia: State and problems
Authors: Bankovic Stanisa , Medarevic Milan , Pantic Damjan , Petrovic Nenad , Sljukic Biljana , Obradovic Snezana
Published: December 2009

Based on the data of the National Forest Inventory, this paper presents the basic characteristics of forest ecosystems in Serbia by different qualitative and quantitative parameters. The following parameters were dealt with: land use, forest ownership, origin, naturalness, preservation status, mixture and structural form of forests, percentage of tree species, stand category, volume distribution by diameter degrees, as well as the quantity of dead wood and carbon stock in the forests of Ser?bia. The analysis of the presented state enables the definition of some of strategic problems which individually and acting together burden our forest ecosystems, and whose detailed elaboration, measures and methods of enhancement will be fully expressed in the highest planning document - National Forest Programme. A special section, but without being sufficiently analytical, presents the main data on the growing stock of the Autonomous Province Kosovo and Metohija taken from the Report of the Norwegian Forestry Group.
The resistance of surfaces treated with oils and waxes to the action of dry heat
Authors: Jaic Milan , Jevtic Petronija
Published: December 2009

Surface treatment of wood can be done with different coatings, and the choice of the appropriate system of processing depends on several factors, such as technological, aesthetic, economic and ecological. Raising awareness of the need to preserve the living and working environment has had a crucial impact on the increase in the use of natural materials for surface treatment of wood - oil and wax. The application of oils and waxes allows surface treated wood to keep the natural look, while protecting it from different influences, which can cause degradation and deterioration of the final product. The paper presents the results of testing the resistance of beech surface (Fagus silvatica L.) processed with linseed oil and beeswax to the action of dry heat. In order to compare the quality of surface treated with oil and/or wax, beech wood treated with 2K-polyurethane coating is taken as a reference of surface treatment of wood. Surfaces treated with beeswax are less resistant to dry heat than those treated with linseed oil, and both showed significantly less resistance than surface treated with 2K-polyurethane coating.
Marketing of non-wood forest products: Case study of the enterprise for forest mushroom processing
Authors: Keca Ljiljana , Rankovic Nenad , Radosavljevic Tomislav
Published: December 2009

Under the impact of climate changes it is increasingly obvious that forestry should rely more strongly on the multi?functional character of the managed resources. In addition to wood, there is a series of non?wood products and services offered by forests. Non?wood forest products and services consist of various fruits of forest trees and shrubs, mushrooms, various objects made of non?wood material, and especially forest social services, such as recreation, tourism, hunting, photo?safari, etc. This paper presents a marketing analysis on the example of the enterprise dealing with the purchase, processing and sale of wild mushrooms and products made of mushrooms. The study applies a modern methodological approach implemented in similar researches.
In vitro interactions between Armillaria species and potential biocontrol fungi
Authors: Keca Nenad
Published: December 2009

Interaction between Armillaria species and seven other fungi were tested in vitro. Tree antagonistic (Trichoderma viride, Trichotecium roseum and Penicillium sp.) and four decaying (Hypholoma fasciculare? Hypholoma capnoides, Phlebiopsis gigantea, and Pleurotus ostreatus) fungi were chosen for this study. The best results were noted for Trichoderma viride, because fungus was able to kill both mycelia and rhizomorphs of Armillaria species, while Hypholoma spp. inhibited both growth of Armillaria colonies and rhizomorph production.
A contribution to the sessile oak site and beech site defining in central Serbia
Authors: Krstic Milun , Cevrljakovic Bojana
Published: December 2009

The study was carried out in sessile oak forests and beech forests in the region central Serbia. The stands are classified as pure stands with the percentage of other species up to 10% per tree number, mixed forests of sessile oak with other species, and mixed forests of beech with other species, whose percentage does not exceed 50%. Altogether 257 stands were monitored - 202 beech stands and 55 sessile oak stands. By the applied method of defining the local heat potential (Lujic, 1960), modified by Ratknic et al. (2001) and Krstic (2004, 2008), which represents possibility of soil heating without vegetation, were determined. In this way, a scale of 162 possible combinations of local heat potential was obtained, which explains more precisely the dependence of beech stands and sessile oak stands on the topographic conditions. By applying the weighted values of the thermal co-ordinates of aspect and slope (E) for each altitudinal belt of 100 m, it was concluded that pure stands have the widest ecological range. Pure beech stands occur at the sites with 34 combinations of thermal co-ordinates E.V=4.6 to 8.12. Pure sessile oak stands occur at the sites with 12 combinations of thermal co-ordinates E.V=5.10 to 8.11. The percentage of mixed beech stands with other broadleaf species is the highest at the sites with the co-ordinate V=10-11 (at the altitudes between 700 and 900 m) is about 60 %. Mixed stands of sessile oak and beech are located on the terrains with combinations of thermal co-ordinates E.V=7.9 to 8.12. By using the local heat potential of a region, it can be identified which sites, i.e. which combinations of exposure, slope and altitude belong to the particular tree species. Consequently, a more reliable selection of tree species can be done for the bio-reclamation of barrens and other deforested terrains.
Ecological and floristic characteristics of the new subassociation Aceri heldreichii-fagetum subass. Carpinetosum betuli on mt. Rudnik
Authors: Perovic Marko , Cvjeticanin Rade
Published: December 2009

Ecological and floristic characteristics of the new subassociation of the Balkan beech and Greek maple plant community with hornbeam (Aceri heldreichii-Fagetum subass. carpinetosum betuli) were studied. This subassociation is recorded and described on Mt. Rudnik, where it occurs at the elevations 950- 1,050 m, on moderate to steep inclinations (10-30?), and cold aspects: northern, northwestern and northeastern. Bedrock consists of sandstones and mudstones. The biological spectrum, ecological spectra and spectrum of distribution types of this community were calculated. The community has phanerophyte-hemicryptophyte character, it is mesophilous regarding soil moisture requirements and temperature requirements, it is neutrophilous to soil acidity, according to light requirements it is tolerant to semi-tolerant. The most numerous group of distribution types is Central European, which confirms the mesophilous character of this community.
Recent trends in extractive metallurgy
Authors: Habashi F.
Published: December 2009

While pyrometallurgical processes are old technology and were the dominant and logical route used to treat sulfide concentrates they are now challenged by new hydrometallurgical processes. In these new processes there have been attempts in the past few years to avoid using autoclaves in the treatment of concentrates of zinc, copper, and nickel. The situation has been recently reversed and pressure hydrometallurgy is being applied in many operations. An outline of these processes is given and the future trend is discussed.
The influence of the silicate slag composition on copper losses during smelting of the sulfide concentrates
Authors: Zivkovic Zivan , Mitevska N. , Mihajlovic Ivan , Nikolic Djordje
Published: December 2009

This paper presents the results of multi-linear regression analysis (MLRA) of the slag composition (SiO2, FeO, Fe3O4, CaO, Al2O3) and the content of copper in the matte on resulting copper content in the slag during smelting of the sulfide concentrates in the reverberatory furnace. When comparing results obtained with MLRA model calculations with values measured at industrial level high degree of fitting is obtained (R2 = 0.974). This indicates that slag composition and content of copper in the matte influences the copper losses in the waste slag with the probability of 95 %.
Thermal behavior of Zefreh dolomite mine (Central Iran)
Authors: Shahraki B.K. , Mehrabi B. , Dabiri R.
Published: December 2009

Dolomite has a large amounts of MgO and is an important raw materials for steel, iron and refractory industries. In this paper thermal behavior of Zefreh dolomite at various temperatures was studied by differential thermal analysis (DTA), Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT - IR) and powder X-ray diffraction (XRD) techniques. The DTA curve shows two endothermic peaks at 772 and 834?C. The first peak is associated with the formation of magnesia (MgO), calcite(CaCO3) and CO2. The second peak represents the decomposition of calcite with formation of CaO and further CO2 release. At 772?C quantitative XRD analysis in atmospheric condition shows small amounts of CaO (less than 2%) which form simultaneously or later than calcite. TGA curve shows total weight loss for decomposition of dolomite is 46.2%. By increasing heating time of samples in furnace, dolomite decomposes in lower temperatures. X-ray diffraction analysis of heat treated samples up to 750?C indicates that dolomite structure changes into calcite. The increases in quartz content accelerated the mechanochemical deformation and amorphization of dolomite phase. At high temperature ( more than 1000?C) Ca3Mg(SiO4)2 and CaSiO4 were formed. XRD and FTIR confirm dolomite decomposition reactions.
Examining the surfaces in used platinum catalysts
Authors: Trumic B. , Stankovic D. , Trujic V.
Published: December 2009

For the purpose of finding more advanced platinum catalyst manufacturing technologies and achieving a higher degree of ammonia oxidation, metallographic characterization has been done on the surface of catalyst gauzes and catalyst gripper gauzes made from platinum and palladium alloys. For the examined samples of gauzes as well as the cross section of the wires, a chemical analysis was provided. The purpose of this paper is the metallographic characterization of examined alloys carried out by way of electronic microscopic scanning, X-rays as well as chemical assays which contributed greatly to a better understanding of the surface deactivation, in other words a better consideration of structural changes occurring on the wire surface.
Thermodynamic modeling of the Al-K system
Authors: Du Y. , Yuan X. , Sun W. , Hu B.
Published: December 2009

A thermodynamic modeling for the Al-K system is conducted. The thermodynamic parameters for liquid, (Al), and (K) are evaluated by using the experimental phase diagram data from the literature. The gas phase is described with an ideal gas model. The calculated Al-K phase diagram agrees well with the experimental data. In particular, the observed monotectic reaction is well described by the present calculation.
Thermodynamic properties of the liquid Bi-Cu-Sn lead-free solder alloys
Authors: Kopyto M. , Garzel G. , Zabdyr L.A.
Published: December 2009

The electromotive force measurement method was employed to determine the thermodynamic properties of liquid Bi-Cu-Sn alloys using solid electrolyte galvanic cells as shown below: Kanthal+Re, Bi-Cu-Sn, SnO2 | Yttria Stabilized Zirconia | air, Pt, Po2=0.2:1 atm Measurements were carried out for three cross-sections with constant Bi/Cu ratio equal to: 1/3, 1 and 3 and for various tin content varying every 10%, resulting in a total of 26 different alloy compositions. The temperature of the measurements varied within the range from 973 to 1325 K. A linear dependence of the e.m.f. on temperature was observed for all alloy compositions and the appropriate line equations were derived. Tin activities were calculated as function of composition and temperature. Results were presented in tables and figures.
Beginning of the metal age in the central Balkans according to the results of the archeometallurgy
Authors: Jovanovic B.
Published: December 2009

The gradual development of the primary copper metallurgy in Balkans starts with production of small jewelry pieces and ends with the serial production of massive tools and weapons. It is confirmed that this metallurgy depended on the contemporary mining, i.e. the available sources of the raw materials. It is also corroborated by the discovery of two Early Eneolithic copper mines: Rudna Glava in Eastern Serbia and Ai-Bunar in Bulgaria /first half and the middle of the 5th millennium BC/. These mines are also the evidence for the local exploitation of the carbonate copper minerals - malachite and azurite. The technology employed is close to the former flint mining in the Late Neolithic; massive pebbles obtained from the neighboring alluvial deposits were used as mining hammers. Identical technology was employed in the mines dating from the later periods /Rudnik, Central Serbia, Jarmovac, Priboj na Limu/. The Vinca culture of the central Balkan followed all metallurgical phases of introduction of metal and use of the carbonate ores /Gradac I - III phase/. This long process of including the metal in wider use lasted generally from the middle of the 5th millennium BC to the end of the 4th millennium BC, i.e. to the appearance of the Bronze Age.
A multi-disciplinary approach to the study of an assemblage of copper-based finds assigned to the prehistory and proto-history of Fucino, Abruzzo, Italy
Authors: Mascelloni M.L. , Cerichelli G. , Ridolfi S.
Published: December 2009

The project aims to characterize, through a body of archaeometric analyses, an assemblage of copperbased finds known as 'Fucino bronzes', most of which lack any finding data. The Fucino bronzes include artefacts that emerged during the drainage of Lake Fucino at the end of the XIX century, as well as bronzes acquired locally or dug out later by several collectors on behalf of the various Italian museums where finds are currently distributed. Our work explores the dynamics related to the objects assembled and relationships between production centres, local workshops, and the emergence of iron. This study proceeds concurrently with the following research and cataloguing procedures: quantification, portable ED-XRF analysis, metallography, and the development of a database. The finds are grouped into three main categories: ornaments and accessories, instruments, and weapons. The quantification is also classed in terms of typology, technology, chronology, and territory whenever possible, in order to establish customized models for the interpretation of data. Metallographic analysis is carried out using optical microscope (OM) and SEM. On this occasion we report the results of selected materials, such as 'Kardiophylakes' that make up about one-third of the known samples in the assemblage, thirty eight of which have a reported provenance from specific Fucino sites.
Early Byzantine metallurgical object at the site Gamzigrad - Romuliana in Eastern Serbia
Authors: Zivic Maja
Published: December 2009

The processing of waste powders from steel production in electric arc furnaces is a world problem. The presence of Fe, Zn, Cd, Pb, etc. in the powders makes them a valuable source for these metals. Zinc is the metal that is most often utilized, which leads to reduction of environmental pollution. The greatest problem in this connection is the presence of chlorine and fluorine in the powders, which influences the electroextraction of zinc in a significantly negative way. The presented paper shows the results from the study of the possibilities for zinc leaching from powders obtained in the steel production in Bulgaria. A detailed characterization of the powders was made using chemical analysis, XRD, DTA and TGA and M?ssbauer spectroscopy. The results from the powder leaching with different solvents give the reason to recommend a technological scheme for the complete and total processing of the waste powders from steel production.
Investigation of archaeometallurgical findings from Felix Romuliana locality
Authors: Zivkovic D. , Strbac N. , Lamut J. , Andjelic B. , Cocic M. , Steharnik M. , Mitovski A.
Published: December 2009

Remains of metallurgical activities have been discovered recently at the locality Felix Romuliana near Zajecar (Eastern Serbia), with a lot of slag occurrences and metal findings. Samples, taken from this locality, have been investigated using different characterization methods - chemical analysis, XRD and SEM-EDX, in order to clarify the Early Byzantine metallurgical activities at Felix Romuliana.
Antimalarial peroxides
Authors: Opsenica Dejan , Solaja Bogdan
Published: December 2009

The problem of endemic malaria continues unabated globally. Malaria affects 40 % of the global population, causing an estimated annual mortality of 1.5-2.7 million people. The World Health Organization (WHO) estimates that 90 % of these deaths occur in sub-Saharan Africa among infants under the age of five. While a vaccine against malaria continues to be elusive, chemotherapy remains the most viable alternative towards treatment of the disease. During last years, the situation has become urgent in many ways, but mainly because of the development of chloroquine-resistant (CQR) strains of Plasmodium falciparum (Pf). The discovery that artemisinin (ART, 1), an active principle of Artemisia annua L., expresses a significant antimalarial activity, especially against CQR strains, opened new approaches for combating malaria. Since the early 1980s, hundreds of semi-synthetic and synthetic peroxides have been developed and tested for their antimalarial activity, the results of which were extensively reviewed. In addition, in therapeutic practice, there is no reported case of drug resistance to these antimalarial peroxides. This review summarizes recent achievements in the area of peroxide drug development for malaria chemotherapy.
Seasonal variations in the leaf surface composition of field grown grapevine plants
Authors: Batovska Daniela , Todorova Iva , Popov Simeon
Published: December 2009

The leaf surface is the first barrier of grapevine plants towards various environmental stressors causing damage in vineyards. For this reason, identification of leaf surface metabolites in grapevine and their putative role in plant-environment interactions is important for viticulture. In this study, the leaf surface components of 16 grapevine plants (Vitis vinifera) growing in an experimental vineyard were analyzed in two consecutive seasons - the summer and the autumn of 2007. Forty-eight individual metabolites typical of the cuticular plant wax were identified by gas chromatography-mass spectrometry (GC-MS). They belonged to the following groups of compounds: hydrocarbons, sterols, terpenes, free and esterified fatty acids, alcohols, aldehydes and ketones. The metabolic profiles of the summer and the autumn samples were statistically different (P < 0.05), which was mainly attributed to the specific insects present in the two seasons and to the adaptation of the grapevine to lower temperatures.
Transition metal complexes with pyrazole-based ligands, Part 29: Reactions of zinc(II) and mercury(II) thiocyanate with 4-acetyl-3-amino-5-methylpyrazole
Authors: Jacimovic Zeljko , Bogdanovic Goran , Holló Berta , Leovac Vukadin , Szécsényi-Mészáros Katalin
Published: December 2009

The work is concerned with the crystal and molecular structures of zinc(II) and mercury(II) complexes with 4-acetyl-3-amino-5-methyl-pyrazole (aamp) of the coordination formulae [Zn(NCS)2(aamp)2[ and (Haamp)2[Hg(SCN)4]. The zinc(II) complex was obtained by the reaction of a warm methanolic solution of aamp with a mixture of zinc(II) nitrate and ammonium thiocyanate, whereas the mercury(II) complex was prepared by the reaction of a warm ethanolic solution of aamp and a warm, slightly acidified aqueous solution of [Hg(SCN)4]2-. Both complexes have a tetrahedral geometry, which in the case of zinc complex is formed by monodentate coordination of two aamp molecules and two isothiocyanate groups. The Zn(II) and Hg(II) atoms have significantly deformed coordination geometry. In both crystal structures the pyrazole derivative has a planar form, probably stabilized by an intramolecular N-H???O hydrogen bond. Apart from the X-ray structural analysis, the isolated complexes were characterized by elemental analysis, IR spectroscopy, conductometric measurements and thermal analysis.
1-naphthylazo derivatives of some 1,3-dicarbonyl compounds and their Cu (II), Ni(II) and Zn(II) complexes
Authors: Krishnankutty K. , Ummathur Basheer , Ummer Perumpalli
Published: December 2009

The coupling of diazotized 1-aminonaphthalene with 1,3-dicarbonyl compounds (acetylacetone, methylacetoacetate and acetoacetanilide) yielded a new series of bidentate ligand systems (HL). Analytical, IR, 1H-NMR and mass spectral data indicate that the compounds exist in the intramolecularly hydrogen bonded keto-hydrazone form. With Ni(II), Cu(II) and Zn(II), these potential monobasic bidentate ligands formed [ML2] type complexes. The IR, 1H- -NMR and mass spectral data of the complexes are consistent with the replacement of the chelated hydrazone proton of the ligand by a metal ion, thus leading to a stable six-membered chelate ring involving the hydrazone nitrogen and the hydrogen bonded carbonyl oxygen. The Ni(II) and Zn(II) chelates are diamagnetic, while the Cu(II) complexes are paramagnetic. In the metal complexes of the naphthylazo derivatives of acetylacetone and methylacetoacetate, the acetyl carbonyl is involved in coordination, whereas in the chelates of the naphthylazo derivative of acetoacetanilide, the anilide carbonyl is bonded with the metal ion.
T-2 toxin adsorption by hectorite
Authors: Dakovic Aleksandra , Sekulic Zivko , Rottinghaus George , Stojanovic Ana , Milicevic Sonja , Kragovic Milan
Published: December 2009

The adsorption of T-2 toxin by the natural smectite mineral-hectorite at pH 3.0, 7.0 and 9.0 was investigated. The results of T-2 toxin adsorption on hectorite showed that the T-2 adsorption capacity decreased with increasing concentration of adsorbent in the suspension for all the investigated pH values. From the adsorption isotherms, an increase in T-2 toxin adsorption with increasing initial T-2 toxin concentration was observed for all the investigated pH values. The T-2 toxin adsorption by hectorite followed a non-linear (Langmuir) type of isotherm at pH 3.0, 7.0 and 9.0, with correlation coefficients (r2) of 0.943 at pH 3.0, 0.919 at pH 7.0 and 0.939 at pH 9.0. The estimated maximum T-2 toxin adsorption by hectorite based on the Langmuir fit to the data (9.178 mg/g at pH 3.0, 9.930 mg/g at pH 7.0, and 19.341 mg/g at pH 9.0), indicated that the adsorption of T-2 toxin by hectorite is pH dependent. The obtained data suggest the existence of specific active sites in hectorite onto which the T-2 toxin is adsorbed.
Densities and excess molar volumes of alcohol + cyclohexylamine mixtures
Authors: Radovic Ivona , Kijevcanin Mirjana , Tasic Aleksandar , Djordjevic Bojan , Serbanovic Slobodan
Published: December 2009

Densities of binary mixtures of 1-propanol, or 2-butanol, or 1-pentanol + cyclohexylamine were measured at temperatures from 288.15 to 313.15 K and atmospheric pressure, while the densities for the system 2-methyl-2-propanol + cyclohexylamine were measured at temperatures from 303.15 to 323.15 K and atmospheric pressure. All measurements were performed using an Anton Paar DMA 5000 digital vibrating-tube densimeter. From the experimental densities, the excess molar volumes, VE, were calculated.