bluuebunny/crossref_metadata_2025_split huggingface dataset:
Demographic life history traits of reproductive natterjack toads (Bufo calamita) vary between northern and southern latitudes
Authors: Sanuy Delfi , Leskovar Christoph , Oromi Neus , Sinsch Ulrich 
Published: August 2006

AbstractDemographic life history traits were investigated in three Bufo calamita populations in Germany (Rhineland-Palatinate: Urmitz, 50°N; 1998-2000) and Spain (Catalonia: Balaguer, Mas de Melons, 41°N; 2004). We used skeletochronology to estimate the age as number of lines of arrested growth in breeding adults collected during the spring breeding period (all localities) and during the summer breeding period (only Urmitz). A data set including the variables sex, age and size of 185 males and of 87 females was analyzed with respect to seven life history traits (age and size at maturity of the youngest first breeders, age variation in first breeders, longevity, potential reproductive lifespan, median lifespan, age-size relationship). Spring and summer cohorts at the German locality differed with respect to longevity and potential reproductive lifespan by one year in favour of the early breeders. The potential consequences on fitness and stability of cohorts are discussed. Latitudinal variation of life history traits was mainly limited to female natterjacks in which along a south-north gradient longevity and potential reproductive lifespan increased while size decreased. These results and a review of published information on natterjack demography suggest that lifetime number of offspring seem to be optimized by locally different trade-offs: large female size at the cost of longevity in southern populations and increased longevity at the cost of size in northern ones.
Sexual size dimorphism in the Cuban treefrog Osteopilus septentrionalis
Authors: Vargas-Salinas Fernando 
Published: August 2006

AbstractTo find out the main cause of the sexual size dimorphism (SSD) in the Cuban treefrog Osteopilus septentrionalis, I studied between April 2002 and April 2004 the breeding behavior and survival of individuals in a population localized in north-western Puerto Rico, West Indies. This species is an explosive breeder whose breeding events lasted one night. Mature females were larger in body size (snout vent-length, SVL) (range 57-107 mm) than mature males (range 41.5-67 mm), and exhibited higher levels of survival (males: 0.72, 95% confidence interval 0.66-0.78; females 0.91, 95% confidence interval 0.88-0.93). Females can increase their reproductive success if they breed with large SVL because large females can lay more eggs than small females. In contrast, the reproductive success of males was not enhanced by large SVL because the mating pattern was random and non-assortative by SVL. Thus, for males it could be better to start to breed with small SVL, and participate in all possible breeding events, which implies high mortality risk. As a consequence, the SSD in O. septentrionalis may be due to fecundity advantages in females, and because males tend to die before reaching larger SVL.
A Re-analysis of the phylogeny of the genus Protobothrops (Reptilia: Viperidae), with particular reference to the systematic position of P. xiangchengensis
Authors: Guo Peng , Zhao Ermi , Zhang Yaping , Pang Junfeng 
Published: August 2006

AbstractBased on three mitochondrial gene fragments (12S rRNA, 16S rRNA, cytochrome b), the phylogeny of Protobothrops is re-analyzed using Maximum-parsimony (MP), Maximum-likelihood (ML), and Bayesian (BI) approaches. All phylogenetic analyses indicate that all putative Protobothrops species examined formed a monophyletic group; however, the intrageneric relationships are still unresolved. The phylogenetic relationships further confirm that P. xiangchengensis is a valid species distinct from P. mucrosquamatus and that it is closely related to P. jerdonii.
Habitat use during the aquatic phase of the newts Triturus vulgaris (L.) and T. cristatus (Laurenti) in central Norway: proposition for a conservation and monitoring area
Authors: Skei Jon , Ringsby Thor , Rønning Lars , Dolmen Dag 
Published: August 2006

AbstractAmphibian populations are declining at an alarming pace in many parts of the world. Consequently, as part of the strategy for establishing a 360 km2 conservation and reference area for amphibians in central Norway, 341 lentic water bodies were surveyed to investigate and briefly describe their hydrography and the occurrence of the newts Triturus vulgaris (L.) and T. cristatus (Laurenti) in the area. In particular we investigated the factors that could explain the presence of the respective newt species, including biotic and abiotic factors. The multiple logistic regression analyses suggested that the presence of T. cristatus was best explained by altitude and ion concentration, both in a nonlinear fashion, whereas fish had a negative effect on T. cristatus, which was never found coexisting with fish. The presence of T. vulgaris was best explained by altitude (linear relationship) and ion concentration (convex relationship), besides the occurrence of T. cristatus. Triturus vulgaris was occasionally found to occur at low densities in ponds having fish. For both species the probability of presence was higher when the opposite newt species was present. pH influenced both species in a convex nonlinear fashion with highest probability of presence around pH 6.5. This area is valuable for conservation, monitoring and reference for marginal amphibian populations. Any decline in their abundance would be discovered relatively quickly, and likely causes could be inferred. It can also serve as a reference area for future comparative studies of amphibians elsewhere.
Body temperature of free-living freshwater turtles, Hydromedusa maximiliani (Testudines, Chelidae)
Authors: Martins Fernando , Souza Franco 
Published: August 2006

AbstractField body temperatures of the Maximilian's snake-necked turtle, Hydromedusa maximiliani, a small freshwater turtle species endemic to Atlantic rainforest mountainous regions in Brazil, were studied. Turtle body temperatures and water temperatures were significantly related, but turtle body temperature averaged 1°C higher than stream water temperature, this difference being statistically significant. A multivariate model revealed that only water temperature was significantly related to turtle body temperature while body size had no effect. There was no effect of sex and life stage on turtle body temperature, implying that water temperature was the main factor determining body temperatures. Thermoconformity was verified for all sampled individuals. The broad implications of these results are also discussed.
Redescription of Leptotyphlops koppesi Amaral, 1954, and description of a new species of the Leptotyphlops dulcis group from Central Brazil (Serpentes: Leptotyphlopidae)
Authors: Passos Paulo , Caramaschi Ulisses , Pinto Roberta 
Published: August 2006

AbstractA new species of Leptotyphlops dulcis group is described from the central Brazilian Cerrado, which is diagnosed by rostral shape, general colour pattern, and number of middorsal and subcaudal scales. This taxon has been commonly misidentified as L. koppesi in some Brazilian collections and by some authors. Leptotyphlops koppesi was described from the municipality of Terenos, State of Mato Grosso do Sul, Brazil, based on a single specimen. Since its original description, only three subsequent records appear in the literature reporting additional specimens of L. koppesi. We redescrib the holotype of Leptotyphlops koppesi, defining its geographic range and diagnose this from all species of L. dulcis group. Data on morphometric and meristic variation are reported for the new species and L. koppesi as well. Comparisons are made between the new species and all other South American species of the L. dulcis group. The hemipenis of the new species has a narrow basal portion and a series of lateral flounces. This general hemipenial morphology is unique among Neotropical leptotyphlopids, otherwise known only from Atlantic Rainforest species L. salgueiroi.
Growth and age of the southernmost distributed gecko of the world (Homonota darwini) studied by skeletochronology
Authors: Piantoni Carla , Cussac Victor , Ibargüengoytía Nora 
Published: August 2006

AbstractHomonota darwini is the southernmost distributed gekkonid species of the world, as it can be found in South America from 35° to 52°S. Age and growth of H. darwini were studied using skeletochronology on diaphyseal femoral cross-sections. Individual ages were assessed after estimating the resorbed rings in relation to snout-vent length (SVL). SVL and age showed a sigmoidal relationship and growth rates showed a shift from premature growth to mature breeding when sexual maturity is achieved. The model indicates that sexual maturity in H. darwini is reached at five years in females and nine in males. Species longevity is estimated to be 17 years, which corresponds to a k-selected trait of late maturity and long life expectancy. Once sexual maturity is achieved, size is a poor indicator of age in this species. These results are discussed in terms of behavioural and physiological adaptations of this species to the strong environmental pressures of the Patagonian steppe. Our results also support the hypothesis that daytime burrow temperatures, which are similar to body temperatures recorded in diurnal lizard species, meet the physiological growth requirements of nocturnal lizard species.
JAZ mediates G1 cell-cycle arrest and apoptosis by positively regulating p53 transcriptional activity
Authors: Yang Mingli , Wu Song , Su Xuekun , May W. Stratford 
Published: August 2006

AbstractWe previously identified JAZ as a novel zinc finger (ZF) protein by screening a murine interleukin-3 (IL-3)–dependent NFS/N1.H7 myeloid cell cDNA library. JAZ is a member of a new class of ZFPs that is evolutionarily conserved and preferentially binds to dsRNA, but its function was unknown. Now, we report that the stress of IL-3 growth factor withdrawal up-regulates JAZ expression in hematopoietic cells in association with p53 activation and induction of cell death. Biochemical analysis reveals that JAZ associates with p53 to stimulate its transcriptional activity in p53-expressing cells, but not in p53-null cells unless complemented with p53. JAZ functions to mediate G1 cell-cycle arrest followed by apoptosis in a p53-dependent mechanism that is associated with up-regulation of p21 and BAX, dephosphorylation of Rb, and repression of cyclin A. Of importance, siRNA “knockdown” of endogenous JAZ inhibits p53 transcriptional activity, decreases the G1/G0 population, and attenuates stress-induced cell death. While JAZ directly binds p53 in vitro in a mechanism requiring p53's C-terminal regulatory domain but independent of dsRNA, the dsRNA-binding ZF domains are required for JAZ's stimulatory role of p53 in vivo by dictating its nuclear localization. Thus, JAZ is a novel negative regulator of cell growth by positively regulating p53.
Mineralogy and Geology of the Maungaparerua Halloysite Deposit in New Zealand
Authors: Murray Haydn H. , Harvey Colin , Smith John M. 
Published: August 2006

AbstractThe Maungaparerua halloysite deposit is located on the North Island of New Zealand some 210 km north of Auckland. The halloysite deposit was formed by hydrothermal alteration of rhyolite flow rocks. Superimposed on the hydrothermally altered halloysite is deep intensive surficial weathering resulting from the humid climate on the extreme tip of the North Island. The deposit has been drilled and the cores have been analyzed mineralogically and chemically. Drilling has shown that the deposit is circular or ovate and covers about 350 acres. The altered rocks contain about 50% quartz and fine amorphous silica and 50% of a mix of halloysite, kaolinite, and allophane with a small amount of plagioclase feldspar in the coarse fraction. The upper 8–30m, with an average of 15m, of the halloysite alteration deposit consists of relatively soft clay. Below this soft clay, which is the result of intense surficial weathering, the clay becomes hard and dense. The halloysite and kaolin from this deposit are mined and beneficiated using wet process techniques of dispersion, centrifugation, leaching, dewatering, and drying. The products are used as filler in paper, paint, and plastics and as a ceramic raw material for producing whiteware and fine china. This deposit is unique in that it contains a very high proportion of halloysite in the clay fraction. The detailed geology, mineralogy, geochemistry, and the physical properties of the clay will be discussed.
Adsorbed Molecules on Solvated Layer Silicates: Surface Mobility and Orientation from ESR Studies
Authors: McBride M. B. 
Published: August 2006

AbstractThe adsorption of nitroxide spin probes on smectites solvated in liquids of greatly different polarity was studied using electron spin resonance (ESR) spectroscopy. Adsorbed probes demonstrate various degrees of restricted rotational motion and alignment at the silicate surfaces, depending upon the properties of the solvating liquid. The results are interpreted in terms of direct surface—molecule interaction modified by solvent competition effects. A fraction of the probe molecules is immobilized in many of the solvated clays because of small spacings between platelets. The data indicate lowered reactivity of surface-adsorbed molecules, especially in the case of hydrated smectites.
Adsorption of Safranine by Na+, Ni2+ and Fe3+ Montmorillonites
Authors: Van Damme H. , Crespin M. , Cruz M. I. , Fripiat J. J. 
Published: August 2006

AbstractThe adsorption of the cationic oxidized safranine S+ by a Na+, Ni2+ and Fe3+ montmorillonite has been studied with X-ray powder diffraction, u.v., visible and i.r. spectroscopy. In solution S+ may be protonated: S+, SH2+ and SH23+ have characteristic spectra in the 500–600 nm region where the clay structure does not absorb. In the Na+ as well as in the Ni2+ and Fe3+ clays, the adsorption of S+ is a cation exchange process accompanied by the protonation of the adsorbed dye such as variable concentrations of M+ (Na+, Ni2+ or Fe3+), S+ and SH2+ are simultaneously present. Protonation activity decreases from Fe3+ to Ni2+ and Na+, being the protonation site the amine group as shown by i.r. In the interlamellar space it seems that a SH2+.. S+ association exists that could be described as a sandwich structure 6.5 Å thick.
Quantitative Analysis of Elements in Sediments and Soils by X-Ray Fluorescence
Authors: Tuncer E. R. , Demirel T. , Lohnes R. A. 
Published: August 2006

AbstractPrevious applications of the method of known additions for quantitative X-ray fluorescent analysis have assumed a linear relationship between peak intensity and concentration of the element being analyzed. This assumption is true for soils or sediments containing small amounts of the element in question. In this paper, an equation is derived which takes into account both absorption and enhancement and thus is applicable to samples containing high concentrations of the element. The equation was tested by analyzing an artificial soil sample containing 60% kaolinite and 40% hematite, i.e. the sample contained 28% by weight iron. The fluorescent analysis utilizing the equation derived here resulted in an iron content of 27%. In addition, nine soils from Hawaii were analyzed by this method and the results of these analyses compared with analyses by atomic absorption. The agreement between the two methods is good. It is concluded that the method and equations proposed here provides a reliable measurement of elements in a soil sample which contains high concentrations of the elements in question.
Clay Mineralogy in Relation to Deltaic Sedimentation Patterns of Desmoinesian Cyclothems in Iowa-Missouri
Authors: Brown L. F. , Bailey S. W. , Cline L. M. , Lister Judith S. 
Published: August 2006

AbstractAlmost four decades of study of Desmoinesian strata of Middle Pennsylvanian age in south-central Iowa and north-central Missouri have provided the stratigraphic control required to test the variation of clay mineralogy vertically and laterally within various paralic clay and shale facies. Local and regional variations in clay mineralogy within Desmoinesian strata are generally predictable and are in agreement with current knowledge of deltaic deposition. A principal environmental variation within a deltaic system is the change from normal marine salinities in deltaic marine environments to brackish- and fresh-water conditions in the marshy delta plains, in upper interdistributary bays, and within flanking interdeltaic embayments. Changes from marine to nonmarine facies coincide with a decrease in illite, and an increase in kaolin, mixed-layer clays, and in the percentage of expansible layers in the mixed-layer clay. The principal clay detritus entering the area was illite, which underwent various degrees of alteration in different aqueous and subaerial environments within deltaic and interdeltaic areas. Clay-mineral composition alone does not provide unique environmental answers. The distribution of clay-mineral suites within these systems, however, both supports the deltaic-interdeltaic depositional model and can be understood within the context of this framework.
Change of b-Dimension with Swelling of Montmorillonite
Authors: Ravina Israela , Low Philip F. 
Published: August 2006

AbstractThe effect of swelling on the b-dimension of Na-saturated, Upton, Wyoming montmorillonite was re-examined using powdered silicon as an internal standard. After being corrected with reference to the internal standard, the b-dimension did not increase through the entire range of swelling as reported previously. It increased up to a water content of ~3.0g/g montmorillonite and remained constant thereafter. However, the diffraction peak of the internal standard shifted towards lower angles at higher water contents. This shift was attributed to a relaxation of the wetter samples away from the knife edge of the diffractometer. Presumably, a similar relaxation occurred in the earlier study and was responsible for the apparent increase in b-dimension at water contents above ~3.0g/g.The b-dimension of Upton montmorillonite saturated with different cations was determined using powdered silicon and a colloidal quartz impurity as internal standards. The water content at maximal swelling decreased as the b-dimension increased.
Synthetic Kaolinites Doped with Fe2+ and Fe3+ Ions
Authors: Angel B. R. , Cuttler A. H. , Richards K. S. , Vincent W. E. J. 
Published: August 2006

AbstractPrevious studies by Electron Spin Resonance (ESR) have established the substitution of Fe3+ and Mg2+ in the kaolinite structure. It is shown that Fe2+ can substitute in kaolinite and stabilize defects which are detectable by ESR in a manner identical to Mg2+. The development of methods of preparing a synthetic kaolinite doped with Fe2+ is described in detail. It is shown that the main ESR signals, which occur at g = 2.0 in natural kaolinites and which previously have been interpreted in terms of iron and magnesium, can be attributed to iron alone.
Identification of Tetramethylammonium Ion in Methylated NH4-Bentonite
Authors: Franco M. A. , Gessa C. , Cariati F. 
Published: August 2006

AbstractTreating NH4-bentonite with diazomethane results in methylation of adsorbed ammonium with the formation of the tetramethylammonium ion. This ion, which can be completely removed through ion exchange, is distinguished in the IR spectrum by a strong band at 1480 cm−1 due to CH3 group bending vibrations. X-ray diffractograms, CEC, and surface area of the clay are not modified by treatment with diazomethane.
Scanning Electron Microscopy of Quartz in Precambrian Cherts and Dolomites from Southern Africa
Authors: le Roux J. , Jackson M. L. 
Published: August 2006

AbstractScanning electron microscopic (SEM) examination of the quartz isolated from chert of Transvaal and Swaziland, of 2000 and 3400 million year (MY) ages, respectively, in southern Africa revealed marked differences in quartz morphology. Well-defined individual euhedral quartz crystals, with polyhedral triple-point faces, were clearly evident on freshly fractured Transvaal chert surfaces as well as with the quartz isolates from the chert. The morphology and coarseness suggest crystal growth with little, if any, metamorphism; however, the δ18O values of 23.8–24.1‰ suggest crystallization temperatures of perhaps 40–45°C. In contrast, fracture surfaces of the older, strongly metamorphosed Swaziland cherts revealed a high degree of grain intergrowth which inhibited fracture between quartz grains. Quartz isolates from these showed strongly interlocked quartz crystal clusters and elongated chips of quartz with poorly defined irregular faces. Intercalation of mineral veins in the cherts on a mm scale and the intergrown character of the quartz grain boundaries provide evidence that the latter cherts have been strongly metamorphosed and recrystallized, in keeping with 14.6–15.1‰ δ18O values, corresponding to 80°C fractionation with water. The SEM micrographs of the fine quartz (1–10 µm) isolated from the Otavi dolomite formation of the 700-MY Damara System and from the 2000-MY Transvaal Dolomite Series revealed well-defined subhedral and euhedral quartz crystals of small size which, together with the 26.9–27.8‰ and 23.8‰ δ18O values, respectively, indicate that these dolomites have been affected little, if any, by post-depositional metamorphism; their crystallization temperatures fall in the range of 25–30 and 40–45°C, respectively.
Amorphous and Crystalline Titanium and Iron-Titanium Oxides in Synthetic Preparations, at Near Ambient Conditions, and in Soil Clays
Authors: Fitzpatrick R. W. , Le Roux J. , Schwertmann U. 
Published: August 2006

AbstractA series of mixed iron and titanium oxide coprecipitates ranging in composition between 0 < Ti/Ti + Fe < 1 was synthesized and aged under varying conditions of pH, temperature and time in order to establish a working model for pedogenic titanium and titano-ferric oxides. X-ray powder diffraction (XRD), selective chemical dissolution, magnetic susceptibility, charge distribution and electron optical data indicate that the freshly prepared Fe-Ti oxides consist of an Fe-rich (Ti-ferrihydrite) phase (Ti/Ti + Fe ⩽ 0.70) having pH-dependent positive charge and a Ti-rich phase (Ti/Ti + Fe ⩾ 0.7) with permanent and pH dependent negative charge.Synthetic Ti-ferrihydrite and amorphous TiO2 were completely soluble in acid ammonium oxalate (2 hr extraction in the dark) whereas poorly crystalline anatase (width at half height, WHH > 2.0°2θ) was partly oxalate soluble. NH4-oxalate soluble Ti was particularly high in soils developed under a cool montane climate (afro-alpine) and lower in soils of warmer subtropical climate, which contain anatase and rutile.Several mixed Fe-Ti crystalline phases were identified after aging NH3 coprecipitates of Fe and Ti nitrate at 70°C and pH 5.5 for 70 days:(1)goethite and hematite in the composition range 0 < Ti/Ti + Fe ⩽ 0.20; at low Ti concentrations (<5 mole %) goethite was favored and/or hematite inhibited(2)microcrystalline pseudorutile in the composition range 0.20 ⩽ Ti/Ti + Fe ⩽ 0.70(3)anatase and ferriferous anatase in the range 0.70 ⩽ Ti/Ti + Fe < 1.0; with decreasing proportion of Ti the crystal-Unity of anatase decreased.The results suggest that secondary or pedogenic Ti-Fe oxides can form by coprecipitation and crystallization in the weathering solution, and emphasize the essential role of water (as opposed to dry oxidation) in the alteration of primary titaniferous minerals.