ALBERT

Description: Ecology, Volume 0, Issue 0, Ahead of Print. The evolutionary pressures that drive long larval planktonic durations in some coastal marine organisms, while allowing direct development in others, have been vigorously debated. We introduce into the argument the asymmetric dispersal of larvae by coastal currents and find that the strength of the currents helps determine which dispersal strategies are evolutionarily stable. In a spatially and temporally uniform coastal ocean of finite extent, direct development is always evolutionarily stable. For passively drifting larvae, long planktonic durations are stable when the ratio of mean to fluctuating currents is small and the rate at which larvae increase in size in the plankton is greater than the mortality rate (both in units of per time). However, larval behavior that reduces downstream larval dispersal for a given time in plankton will be selected for, consistent with widespread observations of behaviors that reduce dispersal of marine larvae. Larvae with long planktonic durations are shown to be favored not for the additional dispersal they allow, but for the additional fecundity that larval feeding in the plankton enables. We analyze the spatial distribution of larval life histories in a large database of coastal marine benthic invertebrates and document a link between ocean circulation and the frequency of planktotrophy in the coastal ocean. The spatial variation in the frequency of species with planktotrophic larvae is largely consistent with our theory; increases in mean currents lead to a decrease in the fraction of species with planktotrophic larvae over a broad range of temperatures.

Description: Homogenous liquid precursor for ZrC – SiC was prepared by blending of Zr ( OC 4 H 9 ) 4 and Poly[(methylsilylene)acetylene]. This precursor could be cured at 250°C and converted into binary ZrC – SiC composite ceramics upon heat treatment at 1700°C. The pyrolysis mechanism and optimal molar ratio of the precursor were investigated by XRD. The morphology and elements analyses were conducted by SEM and corresponding energy-dispersive spectrometer. The evolution of carbon during ceramization was studied by Raman spectroscopy. The results showed that the precursor samples heat treated at 900°C consisted of t- ZrO 2 (main phase) and m- ZrO 2 (minor phase). The higher temperature induced phase transformation and t- ZrO 2 converted into m- ZrO 2 . Further heating led to the formation of ZrC and SiC due to the carbothermal reduction, and the ceramic sample changed from compact to porous due to the generation of carbon oxides. With the increasing molar ratios of C / Zr , the residual oxides in 1700°C ceramic samples converted into ZrC and almost pure ZrC – SiC composite ceramics could be obtained in ZS-3 sample. The Zr , Si , and C elements were well distributed in the obtained ceramics powders and particles with a distribution of 100 ~ 300 nm consisted of well-crystallized ZrC and SiC phases.

Description: Ecology, Volume 94, Issue 9, Page 1955-1965, September 2013. Laboratory studies have demonstrated that the microscopic stages of kelps can rapidly resume development from a delayed state. Like terrestrial seeds or aquatic resting eggs, banks of delayed kelp stages may supplement population recovery after periods of stress, playing an important role for kelp populations that experience adult sporophyte absences due to seasonal or interannual disturbances. We found that removing the microscopic stages from natural rock substratum could prevent the appearance of juvenile kelp sporophytes for three months and the establishment of a diverse kelp assemblage for over four months within a southern California kelp forest. Juveniles were observed within one month in plots where microscopic stages were left intact, which may confer an advantage for the resulting sporophytes as they attain larger sizes before later recruiting neighbors. Microsatellite diversity was high (expected heterozygosity HE ≈ 0.9) for juveniles and adults within our sites. Using a microsatellite-based parentage analysis for the dominant kelp, Macrocystis pyrifera, we estimated that a portion of the new M. pyrifera sporophyte recruits had originated from their parents at least seven months after their parents had disappeared. Similar delay durations have been demonstrated in recent laboratory studies. Additionally, our results suggest that zoospore dispersal distances 〉50 m may be supported by including additional microsatellite loci in the analysis. We propose a mixed-age and, potentially, a mixed-origin bank of M. pyrifera gametophytes promotes maximal genetic diversity in recovering populations and reduces population genetic subdivision and self-fertilization rates for intact populations by promoting the survival of zoospores dispersed 〉10 m and during inhospitable environmental conditions.

Description: Ecology, Volume 94, Issue 9, Page 2109-2110, September 2013. Abstract Total body size, mass or linear measurements, and gonad mass or volumes have been recorded for the North American Pacific coast sea urchins Strongylocentrotus purpuratus, Mesocentrotus (Strongylocentrotus) franciscanus, and Lytechinus pictus by various workers at diverse sites and for varying lengths of time from 1954 to 2009. Some dissections included other body components such as the gut, body wall, and Aristotle's lantern, and some dissections included both wet and dry mass. There are numerous peer-reviewed publications that have used some of these data, but some data have appeared only in graduate theses or in the gray literature. There also are data that have never appeared outside the original data sheets. Historically, data were used to describe reproductive cycles and then to compare responses to stressors such as food limitation or pollution. Differences in temperature among sites also have been explored. More recently, dissection data have linked gonad development to ocean conditions, so called bottom-up forcing. The data set presented here is a historical record of gonad development for a common group of marine invertebrates in intertidal and nearshore environments, which can be used to test hypotheses concerning future changes associated with climate change and ocean acidification along the Pacific Coast of North America.

Description: Ecology, Volume 94, Issue 9, Page 2108-2111, September 2013. Abstract Chytridiomycosis caused by the fungal invasive pathogen Batrachochytrium dendrobatidis (Bd) was first detected in 1999 in Christchurch, New Zealand, in the Australian introduced frog species Litoria raniformis. It was detected in wild native frogs in the critically endangered Leiopelma archeyi in 2001 on the Coromandel Peninsula and has been suggested as responsible for a mass decline (88%) in that population between 1994 and 2002. We report the current distribution, host species and prevalence, where known, of Bd in New Zealand, which is essential for conservation management of New Zealand native frogs (Leiopelma spp.). The data set is structured so that it can be readily added to the Australian Bd database for further analyses. Our data included all regions in New Zealand and six offshore islands at 135 sites with 704 records from 23 contributors spanning collection dates 1930–2010. We report 54 positive sites from 132 positive individuals. We also detail negative findings, but declaring an area free from disease should consider the sensitivity of the test used and numbers of individuals tested. The data also included a comprehensive museum survey testing 152 individuals from five species (20 L. archeyi, 50 L. hochstetteri, 15 L. aurea, 40 L. ewingii, and 27 L. raniformis) from 1930–1999 using histology and Bd-specific immunohistochemistry. All museum specimens were negative, so the 1999 positive result is still the earliest record. In the L. archeyi Coromandel Ranges population, the period prevalence of Bd from 2006 to 2010 was relatively stable at 16%, but the number of animals tested remains low (up to N = 19) due to the now depleted population numbers. The period prevalence of Bd in the L. archeyi Whareorino population has remained both consistent and low (6%) between 2005 and 2010. In L. hochstetteri, L. hamiltoni, and L. pakeka all sampling for Bd has been negative. Positive Bd results have been found in all three Litoria spp., but Bd has not been found in the six offshore areas tested. Most data have been previously unpublished and represent the first confirmed reports of Bd in many regions and species in New Zealand.

Description: Ecology, Volume 94, Issue 9, Page 2055-2065, September 2013. A growing body of research documents the importance of plant genetic effects on arthropod community structure. However, the mechanisms underlying these effects are often unclear. Additionally, plant genetic effects have largely been quantified in common gardens, thus inflating the estimates of their importance by minimizing levels of natural variation. Using Valeriana edulis, a dioecious plant with genetically based sex determination, we conducted surveys and experiments on wild-grown individuals to document field patterns of arthropod association between the sexes and the mechanisms underlying these plant genetic effects. Three years of surveys revealed strong and consistent sex-biased arthropod association in wild-grown plants: female plants supported 4-fold, 1.5-fold, and 4-fold higher densities of aphids, aphid predators, and aphid-tending ants, respectively, compared to males. There was mixed evidence that the female bias for aphids was due to higher plant quality, while we found no difference between plant sexes in aphid preference or the top-down effects of predators and tending ants. Female bias for ants was due to both the greater attractiveness of female plants (direct effect mediated by floral nectar) and an independent, weaker effect of higher aphid abundance on females (density-mediated indirect effect). Conversely, the female bias for predators was driven solely by the greater attractiveness of female plants. We did not find interaction modification, i.e., ant–aphid and predator–aphid interactions were equivalent between plant sexes. Plant sex explained 0.24%, 2.28%, and 4.42% of the variance in aphids, predators, and ants, respectively, values comparable to but slightly weaker than those previously reported from common-garden studies. In contrast to the prediction of diminished plant genetic effects with increasing trophic level, we show how weak indirect effects on predators and parasitoids (via herbivores) can be complemented by strong direct effects via common plant traits (floral resources). In summary, we document direct and indirect effects of genetically based sex on a multi-trophic arthropod community that were expressed in wild-grown plants across multiple years.

Description: Ecology, Volume 94, Issue 9, Page 1893-1897, September 2013. The leaf economics spectrum (LES) has revolutionized the way many ecologists think about quantifying plant ecological trade-offs. In particular, the LES has connected a clear functional trade-off (long-lived leaves with slow carbon capture vs. short-lived leaves with fast carbon capture) to a handful of easily measured leaf traits. Building on this work, community ecologists are now able to quickly assess species carbon-capture strategies, which may have implications for community-level patterns such as competition or succession. However, there are a number of steps in this logic that require careful examination, and a potential danger arises when interpreting leaf-trait variation among species within communities where trait relationships are weak. Using data from 22 diverse communities, we show that relationships among three common functional traits (photosynthetic rate, leaf nitrogen concentration per mass, leaf mass per area) are weak in communities with low variation in leaf life span (LLS), especially communities dominated by herbaceous or deciduous woody species. However, globally there are few LLS data sets for communities dominated by herbaceous or deciduous species, and more data are needed to confirm this pattern. The context-dependent nature of trait relationships at the community level suggests that leaf-trait variation within communities, especially those dominated by herbaceous and deciduous woody species, should be interpreted with caution.

Description: Ecology, Volume 94, Issue 9, Page 2111-2112, September 2013. Abstract We present data from the first five years (2008–2012) of the establishment of the 25.6-ha Smithsonian Conservation Biology Institute (SCBI) Large Forest Dynamics Plot, comprising the initial woody stem census, woody seedling plot surveys, seed rain, and dendrochronological data. The plot is in mature secondary mixed deciduous forest 5 km south of Front Royal, Virginia, USA. The initial plot census enumerated 38 932 free-standing living stems and 29 991 living individuals ≥1 cm dbh comprising 62 species, 38 genera, and 26 families, along with an additional 1248 dead/missing standing stems, for a total of 40 180 stems. Dominant canopy trees include tulip poplar (Liriodendron tulipifera), hickories (Carya spp.), oaks (Quercus spp.), white ash (Fraxinus americana), and black gum (Nyssa sylvatica). Prominent understory components include spicebush (Lindera benzoin), pawpaw (Asimina triloba), American hornbeam (Carpinus caroliniana), witchhazel (Hamamelis virginiana), and eastern redbud (Cercis canadensis). Few species predominate numerically on the plot; seven species have 〉1000 individuals (71.3% of the total). Mean stand density was 1179 living individuals/ha, while mean basal area was 34.1 m2/ha. Of the total plot area, 4 ha have had white-tailed deer (Odocoileus virginianus) exclusion since 1990. Woody seedling surveys from 2010–2012 in 354 1-m2 plots measured 19 415 seedlings of 47 species, from new germinants up to 1 cm dbh. Community-wide seed rain data from 200 0.5-m2 litterfall traps yielded a total of 9197 records from 37 species. Long-term seed data collected from 1986–2011 for Quercus and Carya within the exclosure and two replicate sites are also presented, documenting considerable annual variation in mast production. Dendrochronological data from 492 tree cores suggested the major canopy trees established circa 1900, but scattered trees of several species existed earlier. Large-scale forest dynamics plots employing standardized methodology have a long, rich history in the tropics. Similar plots in the temperate zone have been largely lacking, however. The SCBI plot represents one of the first of its kind in the Smithsonian Global Earth Observatory's recently established network of such plots, complementing its well-known network of tropical forest plots and enabling comparative studies on forest ecology and climate change at the global scale.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. The installation of green roofs, defined here as rooftops with a shallow soil cover and extensive vegetation, has been proposed as a possible measure to mitigate the loss of green space caused by the steady growth of cities. However, the effectiveness of green roofs in supporting arthropod communities, and the extent to which they facilitate connectivity of these communities within the urban environment is currently largely unknown. We investigated the variation of species community composition (β-diversity) of four arthropod groups with contrasting mobility (Carabidae, Araneae, Curculionidae and Apidae) on 40 green roofs and 40 extensively managed green sites on the ground in the city of Zurich, Switzerland. With redundancy analysis and variation partitioning i) we disentangled the relative importance of local environmental conditions, the surrounding land-cover composition, and habitat connectivity on species community composition. ii) We searched for specific spatial scales of habitat connectivity for the different arthropod groups. iii) Finally, we discussed the ecological and functional value of green roofs in cities. Our study revealed that on green roofs community composition of highly mobile arthropod groups (bees and weevils) were mainly shaped by habitat connectivity while low mobile arthropod groups (carabids and spiders) were more influenced by local environmental conditions. A similar but less pronounced pattern was found for ground communities. The high importance of habitat connectivity in shaping highly mobile species community composition indicates that these green roof communities are substantially connected by the frequent exchange of individuals among surrounding green roofs. On the other hand, low mobile species communities on green roofs are more likely connected to ground sites than to other green roofs. The integration of green roofs in urban spatial planning strategies has great potential to enable higher connectivity among green spaces, so that eventually even communities of low mobile species become connected. Furthermore, improving the design of green roofs (composition and configuration of vegetation and soil types) could enhance the ecological value especially for low mobile species.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Assessing trait responses to environmental gradients requires the simultaneous analysis of the information contained in three tables: L (species distribution across samples), R (environmental characteristics of samples) and Q (species traits). Among the available methods, the so-called fourth-corner and RLQ methods are two appealing alternatives that provide a direct way to test and estimate trait-environment relationships. Both methods are based on the analysis of the fourth-corner matrix which crosses traits and environmental variables weighted by species abundances. However, they greatly differ in their outputs: RLQ is a multivariate technique that provides ordination scores to summarize the joint structure among the three tables, whereas the fourth-corner method mainly tests for individual trait-environment relationships (i.e. one trait and one environmental variable at a time). Here, we illustrate how the complementarity between these two methods can be exploited to promote new ecological knowledge and to improve the study of trait-environment relationships. After a short description of each method, we apply them to real ecological data to present their different outputs and provide hints about the gain resulting from their combined use.

Description: Ce -doped BaTiO 3 -based ceramics were prepared and studied to satisfy ultra-broad temperature stability (from −55°C to 300°C, capacitance variation rate based on C 20°C is within ±15%). The sample with 0.6 mol% CeO 2 succeeds to achieve this performance with a remarkably high ceiling temperature of 300°C. Meanwhile, the sample has good dielectric and electrical properties at room temperature (ε r  = 1667, tanδ = 1.478%, ρ V  = 5.9 × 10 12  Ω·cm). Ce ion can substitute for Ti ion as Ce 4+ or Ba ion as Ce 3+ . The substitution decreases the spontaneous polarization of BaTiO 3 , and then weakens the ferroelectricity of BaTiO 3 . As a result, the temperature stability of samples is improved obviously. Besides, CeO 2 addition promotes the formation of exaggerated grains, which are consisting of Ba 6 Ti 17 O 40 .

Description: This study aims to optimize quantitative X-ray diffraction (XRD) mineralogical analysis of the minority phases in clinker. The proposed method consists of applying Rietveld quantitative refinement to the XRD patterns for both clinker and the insoluble residue remaining after it is attacked with methanol and salicylic acid (Takashima method). The method was tested with industrial clinker and the same material after modifying its mineralogy by refiring at 1500°C followed by slow cooling. The findings showed that the C 4 AF / C 3 A ratios for quickly and gradually cooled clinker were much higher when the clinker diffractograms were refined with the Rietveld procedure than when the proposed method was used. The proportion of C 3 A found with the proposed method was ≈2.8-fold higher than when Rietveld only was applied to the diffractograms for clinkers. Taken together, the refinement data for the two materials (clinker and Takashima residua) revealed that Rietveld quantitative XRD applied to clinker underestimates the low C 3 A content. These findings are supported by postsulfate attack durability studies conducted on cements prepared with the two clinkers.

Description: The effect of increasing poling fields on the properties of (1− x )BZT– x BCT compositions across the morphotropic phase boundary (MPB) is studied using large signal polarization and strain, small signal permittivity and piezoelectric coefficient, and XRD measurements. Successive poling causes charge carrier migration inducing an internal bias field, which becomes large with respect to the coercive field resulting in biased ferroelectric and ferroelastic switching. Improvements in piezoelectric coefficient of 9% are significantly smaller in the tetragonal 60BCT composition compared with the improvement of approximately 50% in the rhombohedral 40BCT and MPB 50BCT compositions. While the properties continue to change with increased poling fields, the remnant ferroelastic domain texture parallel to the field direction, as observed from XRD, stays approximately constant. The improvement in overall domain alignment leading to largely enhanced intrinsic piezoelectricity originates from the alignment of 180° domains and possibly non-180° domains in grains with orientations inclined to the electric field. As a result, poling is most effective in BZT–BCT materials that have low coercive fields, show low distortions and possess more polarization orientations, such as compositions in the rhombohedral phase field or near the MPB.

Description: The defect chemistry-modulated dielectric properties of dense yttria-doped zirconia ceramics prepared by conventional sintering (at 1350°C–1500°C) and electric field-assisted flash sintering (55 V/cm at 900°C) were studied by impedance spectroscopy. While the bulk dielectric properties from both sets of samples showed only small and insignificant changes in conductivity and permittivity, respectively, a huge increase of these properties was measured for the grain boundaries in the flash sintered specimens. A close analysis of these results suggests that flash sintering reduced grain-boundary thickness (by about 30%), while increasing the concentration of oxygen vacancies near these interfaces (by about 49%). The underlying mechanism proposed is electric field-assisted generation and accommodation of defects in the space-charge layers adjacent to the grain surface. The changes in measured permittivity are attributed to the boundary thickness effect on capacitance, while conductivity involved variations in its defect density-dependent intrinsic value, accounting for changes also observed in grain-boundary relaxation frequencies. Therefore, in terms of modifications to the specific dielectric properties of these materials, the overall consequence of flash sintering was to considerably lower the semi-blocking character of the grain boundaries.

Description: This article presents a detailed study on the nanoscaled interface between microelongated gold particles (GP) and biphase leucite/feldspar glass-ceramic matrix. The glass-ceramic composite with a nonuniform GP distribution was processed through hot-pressing under vacuum using a commercial dental ceramic furnace for glass-ceramic dental crown manufacturing. Heat treatments at 900°C, 1100°C, and 1300°C were conducted, and microstructural features along the interface were used to verify the chemical reactions between GP and glass-ceramic matrix. It was observed that the amorphous glass-ceramic matrix had nanoscaled biphase structures, and the distributed nanoscaled amorphous leucite phase was attracted to GP during hot-pressing, and was more reactive with GP than the feldspar phase. The thickness of the interfacial phase formed through chemical reactions between GP and glass-ceramic matrix is around 30 nm. The chemically bonded interface has contributed significantly toward the substantial improvements in both strength and toughness of the GP-reinforced glass-ceramic matrix composite. Characterization techniques, including X-ray diffraction and field-emission scanning electron Microscopy, incorporating X-ray microanalysis using energy dispersive spectrometry, have been employed in this study.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Insect mutualisms can have disproportionately large impacts on local arthropod and plant communities and their responses to climatic change. The objective of this study was to determine if the presence of insect mutualisms affects host plant and herbivore responses to warming. Using open-top warming chambers at Harvard Forest, MA, USA, we manipulated temperature and presence of ants and Chaitophorus populicola aphids on Populus tremuloides host plants and monitored ant attendance and persistence of C. populicola, predator abundance, plant stress, and abundance of Myzus persicae, a pest aphid that colonized plants during the experiment. We found that, regardless of warming, C. populicola persistence was higher when tended by ants, and some ant species increased aphid persistence more than others. Warming had negligible direct but strong indirect effects on plant stress. Plant stress decreased with warming only when both ants and C. populicola aphids were present and engaged in mutualism. Plant stress was increased by warming- induced reductions in predator abundance and increases in M. persicae aphid abundance. Altogether, these findings suggest that insect mutualisms could buffer the effects of warming on specialist herbivores and plants, but, when mutualisms are not intact, the direct effects of warming on predators and generalist herbivores yield strong indirect effects of warming on plants.

Description: Recent investigations have revealed the great potential of Raman spectroscopy for the characterization of clinker minerals and commercial Portland cements. The usefulness of this technique for the identification of anhydrous, hydrated, and carbonated phases in cement-based materials has been demonstrated. In the present work, the application of micro-Raman spectroscopy for the characterization of the main clinker phases of calcium aluminate cements and calcium sulfoaluminate cement is explored. The main stable hydrated phases as well as several important carbonated phases are investigated. Raman measurements on the following phases are reported: (i) pure, unhydrated phases: CA, C 12 A 7 , CA 2 , C 2 AS, cubic- C 3 A , C 4 AF, and C 4 A 3 ; (ii) hydrated phases: ettringite, monosulfoaluminate, and hydrogarnet ( C 3 AH 6 ); (iii) carboaluminate phases: hemicarboaluminate and monocarboaluminate. The present results, which are discussed in terms of the internal vibrational modes of the aluminate, carbonate, and sulfate molecular groups as well as stretching O–H vibrations, show the ability of Raman spectroscopy to identify the main hydrated and unhydrated phases in the aluminate and sulfoaluminate cements. The Raman spectra obtained in this work provide an extended database to the existing data published in the literature.

Description: Acmite ( NaFeSi 2 O 6 ) films were formed on steel coupons via solvothermal reaction of silica, sodium hydroxide, and 1, 4-butanediol in an autoclave under autogenous pressure. Systematic variation in processing variables led to homogenous coatings comprised of pinacoidal acmite grains with an average grain size of ~33 μm. The coatings were produced on the steel coupons from reactant conditions of 0.635 m SiO 2 , 2.546 m NaOH , and 3.087 m 1,4-butanediol for 72 h at 240°C.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. The processes that structure assemblages of species in hyper-diverse genera, such as Ficus (Moraceae), are not well understood. Functional diversity of co-occurring species can reveal evidence for assembly processes; however, intraspecific variation may weaken species-level patterns. We studied whether functional and phylogenetic diversity of Ficus species indicated the effects of spatial variation in filters associated with topography or niche partitioning related to resource use and biotic interactions. We also asked whether individual trait patterns supported species-level patterns. We studied six traits (leaf area, succulence, specific leaf area: SLA, maximum DBH, fruit size, and latex exudation) for 22 Ficus species and 335 individuals {greater than or equal to} 10 cm DBH on a 20-ha forest plot in China. We found that higher elevation was correlated to changes in mean and reduced diversity of five traits, possibly due to frequent disturbances at higher elevations that favored fast-growing, poorly defended species with high SLA. Maximum DBH showed phylogenetic conservatism but high diversity among co-occurring species, suggesting adult stature is an important axis of within-quadrat niche partitioning. At the individual level, trait patterns were qualitatively consistent but were stronger than species-level patterns, especially for the leaf traits with the greatest intraspecific variation (SLA and succulence). Individual-level SLA exhibited the strongest evidence for both among and within-quadrat niche partitioning and indicated elevational filtering. Local niche partitioning and elevational filtering likely play an important role in maintaining species and functional diversity in the most speciose genus at our study site. Our results highlight the importance of individual variation, as it may reveal otherwise obscured niche effects.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Inputs of terrestrial organic carbon (t-OC) into lakes are often considered a resource subsidy for aquatic consumer production. Although there is evidence that terrestrial carbon can be incorporated into the tissues of aquatic consumers, its ability to enhance consumer production has been debated. Our research aims to evaluate the net effect of t-OC input on zooplankton. We used a survey of zooplankton production and resource use in ten lakes along a naturally occurring gradient of t-OC concentration to address these questions. Total and group-specific zooplankton production was negatively related to t-OC. Residual variation in zooplankton production that was not explained by t-OC was negatively related to terrestrial resource use (allochthony) by zooplankton. These results challenge the designation of terrestrial carbon as a resource subsidy; rather, the negative effect of reduced light penetration on the amount of suitable habitat and the low resource quality of t-OC appear to diminish zooplankton production. Our findings suggest that ongoing continental-scale increases in t-OC concentrations of lakes will likely have negative impacts on the productivity of aquatic food webs.

Description: A 50:50 vol% MgO – Y 2 O 3 nanocomposite with ~150 nm grain size was prepared in an attempt to make 3–5 μm infrared-transmitting windows with increased durability and thermal shock resistance. Flexure strength of the composite at 21°C is 679 MPa for 0.88 cm 2 under load. Hardness is consistent with that of the constituents with similar grain size. For 3-mm-thick material at 4.85 μm, the total scatter loss is 1.5%, forward scatter is 0.2%, and absorptance is 1.8%. Optical scatter below 2 μm is 100%. Variable intensity OH absorption (~6% absorptance) is observed near 3 μm. The refractive index is ~0.4% below the volume-fraction-weighted average of those of the constituents. Thermal expansion is equal to the volume-fraction-weighted average of expansion of the constituents. Specific heat capacity is equal to the mass-fraction-weighted average of heat capacities of the constituents. Thermal conductivity lies between those of the constituents up to 1200 K. Elastic constants lie between those of the constituents. The Hasselman mild thermal shock resistance parameter for the composite is twice as great as that of common 3–5 μm window materials, but half as great as that of c -plane sapphire.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Ecological structures and processes occur at specific spatio-temporal scales, and interactions that occur across multiple scales mediate scale-specific (e.g. individual, community, local or regional) responses to disturbance. Despite the importance of scale, explicitly incorporating a multi-scale perspective into research and management actions remains a challenge. The discontinuity hypothesis provides a fertile avenue for addressing this problem, by linking measureable proxies to inherent scales of structure within ecosystems. Here we outline the conceptual framework underlying discontinuities, and review the evidence supporting the discontinuity hypothesis in ecological systems. Next we explore the utility of this approach for understanding cross-scale patterns and the organization of ecosystems by describing recent advances for examining non-linear responses to disturbance, and phenomena such as extinctions, invasions, and resilience. To stimulate new research, we present methods for performing discontinuity analysis, detail outstanding knowledge gaps, and discuss potential approaches for addressing these gaps.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Cross-ecosystem fluxes can intertwine otherwise disparate food webs, but the effects of biodiversity at the genotypic level on fluxes across ecosystems boundaries is not known. Fresh leaves, which vary in traits such as defensive compounds against terrestrial herbivores, drop off trees and enter streams, providing a vital resource for riverine organisms. We demonstrate substantial variation in decomposition rates among individual trees in four different rivers in the Olympic Peninsula of Washington State, USA. We show that locally derived red alder leaf litter decomposes on average 24% faster than red alder leaf litter introduced from other riparian zones. Within rivers, leaves downstream of their parent trees decompose nearly as quickly as leaves from local trees. Leaves upstream of the parent tree decomposed as slowly as leaves from trees growing alongside different rivers. Over time, aquatic decomposer communities have locally adapted to the specific trees supplying the riparian subsidies. In energy-limited environments, such as small shaded streams, consumers must be efficient foragers. Our results indicate that this pressure for efficiency has led to adaptation at a particularly fine scale. More broadly, these results illustrate how genetic diversity and the effects of selection in one ecosystem can indirectly shape the structure of other ecosystems through ecological fluxes across boundaries.

Description: In this work, novel Y 2 Si 2 O 7 / ZrO 2 composites were developed for structural and coating applications by taking advantage of their unique properties, such as good damage tolerance, tunable mechanical properties, and superior wear resistance. The γ- Y 2 Si 2 O 7 / ZrO 2 composites showed improved mechanical properties compared to the γ- Y 2 Si 2 O 7 matrix material, that is, the Young's modulus was enhanced from 155 to 188 GPa (121%) and the flexural strength from 135 to 254 MPa (181%); when the amount of ZrO 2 was increased from 0 to 50 vol%, the γ- Y 2 Si 2 O 7 / ZrO 2 composites also presented relatively high facture toughness (〉1.7 MPa·m 1/2 ), but this exhibited an inverse relationship with the ZrO 2 content. The composition–mechanical property–tribology relationships of the Y 2 Si 2 O 7 / ZrO 2 composites were elucidated. The wear resistance of the composites is not only influenced by the applied load, hardness, strength, toughness, and rigidity but also effectively depends on micromechanical stability properties of the microstructures. The easy growth of subcritical microcracks in Y 2 Si 2 O 7 grains and at grain boundaries significantly contributes to the macroscopic fracture toughness, but promotes the pull-out of individual grains, thus resulting in a lack of correlation between the wear rate and the macroscopic fracture toughness of the composites.

Description: The as-prepared BiFeO 3 ceramic shows a piezoelectric d 33 coefficient of −14 pC/N, that is, an obvious ferroelectric self-poling phenomenon. The temperature gradient between the two surfaces of BiFeO 3 ceramic was intentionally enlarged when BiFeO 3 was prepared with a rapid liquid sintering method. This temperature gradient and the corresponding thermal strain can introduce defect dipoles through separating bismuth vacancies from oxygen vacancies. A mass of these dipoles introduce a macroscopic internal electric field ( E in ) which downward poles BiFeO 3 ceramic during its cooling down process. As expected, an E in of 〉10 kV/cm is confirmed by the asymmetrical polarization/strain versus electric field curves.

Description: The effect of Ba content on the stress sensitivity of the antiferroelectric to ferroelectric phase transition in ( Pb 0.94− x La 0.04 Ba x )[( Zr 0.60 Sn 0.40 ) 0.84 Ti 0.16 ] O 3 ceramics is investigated through monitoring electric field-induced polarization and longitudinal strain under compressive prestresses. It is found that incorporation of Ba significantly suppresses the stress sensitivity of the phase transition, as manifested by slight decreases under prestresses up to 100 MPa in the maximum polarization ( P m ) and longitudinal strain ( x m ). The energy storage density is even increased under the mechanical confinement in compositions x  = 0.02 and 0.04. X-ray diffraction, transmission electron microscopy, and dielectric measurements indicate that the suppressed stress sensitivity is associated with the disruption of micrometersized antiferroelectric domains into nanodomains and the transition from antiferroelectric to relaxor behavior.

Description: Powders and nanoceramics composed of composites of CoFe 2 O 4 , CoFe 2 , and a small amount of FeO were prepared by heating CoFe 2 O 4 powder in reducing atmosphere and by sintering the product of reducing reaction at 350°C via spark plasma sintering technology. In the powders, increase in the molar ratios of CoFe 2 : CoFe 2 O 4 and a great change in magnetic parameters were observed with the change in heating temperature from 300°C to 400°C, and the dominance of dipole interaction over exchange coupling in the interparticle interactions was confirmed by the steps in magnetic hysteresis loops and the negative Henkel plots. However, in the nanoceramics, significant enhancement in exchange coupling was found when the sintering temperature was raised to 500°C and 650°C, which was confirmed by both the positivity of Henkel plot and the single-phase style of the magnetic hysteresis loop.

Description: Gas adsorption porosity measurement of geopolymers (GPs) is required for quantitative understanding of such mesoporous structures, but the complex nature of the GP system makes analysis difficult. Previous results in the literature are often ambiguous or contradictory. A systematic investigation of metakaolin GP gas adsorption results was conducted to optimize the use of this measurement technique and verify that results match known theory about GP structure. It was found that GP undergoes structural change upon degassing at 100°C or higher. If and only if this change is prevented by degassing at a lower temperature could it be shown that specific surface area and total gas adsorption increases with both increasing curing temperature and decreased Si : Al ratio. This observation is consistent with previous suggestions of increased zeolitic character under these conditions, where previous gas adsorption investigations had not observed this expected relationship. Hydrogen physisorption is proposed as a substitute technique for micropore isotherms in GPs due to the difficulty of removing trace gasses from GPs and the measurement effect of such gasses at high vacuum. A hydrogen physisorption isotherm qualitatively resembled an equivalent nitrogen micropore isotherm.

Description: In this work, the role of europium doping of glasses formulated in the ternary system ZnO – CdO – TeO 2 is described. The Eu -doped oxide glasses were prepared by the conventional melt-quenching method and by using three different compositions. Structural studies reveal that there exists a good affinity between Cd and some rare earth (RE) ions to form the crystalline phase. The X-ray diffraction (XRD) diagrams display that the structure of these glasses is amorphous and with the increase in CdO content and the compatibility of Eu 3+ , there is a tendency to form nanocrystals of CdTe 2 O 5 . The scanning electron microscopic (SEM) observation of their microstructure confirms the presence of phase separation. Differential thermal analysis (DTA) of these glasses showed small exothermic peaks noted around 450°C for the V2 glass and 480°C for V1 and V3 glasses, which could be attributed to the formation of these crystals. The infrared spectra showed a main absorption band around 800–600 cm −1 corresponding to the Te – O stretching mode in TeO 4 and TeO 3 groups. By optical absorption (OA), the band gap ( E g ) for each glass was determined; these values were 3.27, 3.14, and 3.3 eV for the V1–V3 glasses, respectively. Furthermore, the presence of Eu 3+ was detected in the 370–470 nm short-range wavelengths. The photoluminescence (PL) experiments of the glasses showed light emission due to the following transitions: 5D0 → 7F1, 5D0 → 7F2, 5D0 → 7F3, and 5D0 → 7F4.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Environmental conditions and individual strategies in early life may have a profound effect on fitness. A critical moment in the life of an organism occurs when an individual reaches independence and stops receiving benefits from its relatives. Understanding the consequences of individual strategies at the time of independence requires quantification of their fitness effects. We explored this period in the red grouse (Lagopus lagopus scoticus). In this system, testosterone and parasite (Trichostrongylus tenuis) levels are known to influence survival and reproduction; the two key components of individual fitness. We experimentally and simultaneously manipulated testosterone and parasites at three levels (high, intermediate, and control levels for both factors) in 195 young males in 5 populations using a factorial experimental design. We explored the effects of our treatments on fitness by monitoring reproduction and survival throughout the life of all males and estimating λind, a rate-sensitive index of fitness. Parasite challenges increased the number of worms with a time lag, as previously found. However, we did not find significant effects of parasite manipulations on fitness, possibly because parasite abundance did not increase to harmful levels. Our hormone manipulation was successful at increasing testosterone at three different levels. Such increases in hormone levels decreased overall fitness. This was caused by reduced offspring production in the first breeding attempt rather than by any effect of the treatment on bird survival. Our results highlight that investing in high testosterone levels at independence, a strategy that might enhance short-term recruitment probability in territorial species such as red grouse, has a fitness cost, and can influence the resolution of the trade-off between reproduction and survival later in life.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. The study of population dynamics requires unbiased, precise estimates of abundance and vital rates that account for the demographic structure inherent in all wildlife and plant populations. Traditionally, these estimates have only been available through approaches that rely on intensive capture-recapture data. We extend recently developed N-mixture models to demonstrate how demographic parameters and abundance can be estimated for structured populations using only stage-structured count data. Our modeling framework can be used to make reliable inferences on abundance as well as recruitment, immigration, stage-specific survival, and detection rates during sampling. We present a range of simulations to illustrate the data requirements, including the number of years and locations necessary for accurate and precise parameter estimates. We apply our modeling framework to a population of northern dusky salamanders (Desmognathus fuscus) in the mid-Atlantic region and find that the population is unexpectedly declining. Our approach represents a valuable advance in the estimation of population dynamics using multi-state data from unmarked individuals and should additionally be useful in the development of integrated models that combine data from intensive (e.g., capture-recapture) and extensive (e.g., counts) data sources.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Long distance seed dispersal (LDD) is considered a crucial determinant of tree distributions, but its effects depend on demographic processes that enable seeds to establish into adults and that remain poorly understood at large spatial scales. We estimated rates of seed arrival, germination, and survival and growth for a canopy tree species (Miliusa horsfieldii), in a landscape spanning evergreen forest where the species' abundance is high to deciduous forest where it is extremely low. We then used an individual-based model (IBM) to predict sapling establishment and compare the relative importance of seed arrival and establishment in explaining the observed distribution of seedlings. Individuals in deciduous forest, far from the source population, experienced multiple benefits -- increased germination rate, new recruit height, seedling survival and growth -- from being in a habitat where conspecifics were almost absent. The net effect of these spatial differences in demographic processes was significantly higher estimated sapling establishment probabilities for seeds dispersed long distances into deciduous forest. Despite the high rate of establishment in this habitat, Miliusa is rare in the deciduous forest because arrival of seeds at long distances from the source population is extremely low. Across the entire landscape, the spatial pattern of seed arrival is much more important than the spatial pattern of establishment for explaining observed seedling distributions. By using dynamic models to link demographic data to spatial patterns, we conclude that LDD plays a pivotal role in the distribution of this tree in its native habitat.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Individual growth rates and survival are major determinants of individual fitness, population size structure and community dynamics. The relationships between growth rate, survival and temperature may thus be important for predicting biological responses to climate change. Although it is well known that growth rates and survival are affected by competition and predation in addition to temperature, the combined effect of these factors on growth rates, survival and size structure has rarely been investigated simultaneously in the same ecological system. To address this question, we conducted experiments on the larvae of two species of damselflies and determined the temperature-dependence of growth rates and survival and the resulting cohort size structure under three scenarios of increasing ecological complexity: no competition, intraspecific competition and interspecific competition. In one species, the relationship between growth rate and temperature became steeper in the presence of competitors whereas that of survival remained unchanged. In the other species, the relationship between growth rate and temperature was unaffected by competitive interactions but survival was greatly reduced at high temperatures in the presence of interspecific competitors. We also found that the combined effect of competitive interactions and temperature on cohort size structure differed from the effects of these factors in isolation. Together, these findings suggest that it will be challenging to scale up information from traditional, single-species laboratory studies to the population and community level.

Description: The conductivity of nominal CaWO 4 , CaW 0.99 Ta 0.01 O 4–δ , 0.7( CaWO 4 )–0.3( La 0.99 Ca 0.01 NbO 4–δ ), and Ca 0.9 La 0.1 WO 4+δ has been studied by means of a.c. impedance measurements. Proton conductivity was observed for CaW 0.99 Ta 0.01 O 4–δ , which displayed exothermic hydration with enthalpy and entropy of –82 kJ/mol and –120 J/molK, respectively. The proton mobility in CaW 0.99 Ta 0.01 O 4–δ was low, with enthalpy and preexponential factor of mobility of 82 kJ/mol and 0.7 cm 2 K/Vs. The high enthalpy of mobility is interpreted to reflect association between the acceptor dopant and protonic defects, whereas the low preexponential factor of mobility may reflect a lower proton concentration than assumed. Rietveld refinement indicated low solubilities of La on Ca -site and Ta on W-site. Proton conductivity was also observed in undoped CaWO 4 , however, not in Ca 0.9 La 0.1 WO 4+δ . The conductivity of 0.7( CaWO 4 )–0.3( La 0.99 Ca 0.01 NbO 4–δ ) behaved much like that of undoped LaNbO 4 , likely due to a very low acceptor dopant concentration.

Description: A new lead-free BNT-based piezoelectric ceramics of (1 −  x ) Bi 0.5 Na 0.5 TiO 3 – x Bi ( Al 0.5 Ga 0.5 ) O 3 ( x  = 0, 0.02, 0.03, 0.04, and 0.05) were synthesized using a conventional ceramic fabrication method. Their structures and electrical properties were investigated. All the samples show a typical ferroelectric P ( E ) loops and S ( E ) curves at room temperature. The optimal properties are obtained at the composition of the x  = 0.03. The substitution of Bi ( Al 0.5 Ga 0.5 ) O 3 enhances piezoelectric constant and increases Curie temperature from 58 pC/N and 310°C of pure BNT to 93 pC/N and 325°C of the x  = 0.03. The temperature-dependent P ( E ) loops and S ( E ) curves of 0.97BNT–0.03BAG indicate that phase transition from ferroelectric to antiferroelectric takes place over a very wide temperature region from 80°C to 180°C. The results show that the introduction of BAG improves the electrical properties of BNT.

Description: We studied ancient enamels on gilded copper from a collection of archeological horse harness pendants of the Museo Instituto Valencia de Don Juan (Madrid, Spain) to test the benefits of a new, nondestructive analytical methodology based on chemometric analysis (i.e., Principal Component Analysis, PCA) on micro-ATR-FTIR spectral data and chemical quantification using SEM-EDS. The novelty of this approach was threefold: (i) PCA allowed the discrimination of the different harness pendants of known origin and attributed to the 14th and 15th centuries according to the chemical complex composition, nanostructure, glass weathering, and/or coloring mechanisms of each colored enamel, separately (i.e., red, purple, blue, and white), (ii) it is a cheap, easily available and nondestructive methodology that enables us to (iii) draw archeological conclusions about the quality of the manufacturing process, reassess the chronology of these objects and attempt to attribute them to different workshops according to the different traditional recipes identified. In particular, the enamels were made of alkali and/or alkaline earth lead-glass with a wide range of chemical compounds in the form of pigments or opacifiers. Two types of coloring mechanisms were identified, colloidal particles such as copper-ruby for red enamels, and ionic mechanisms such as Fe (II) and Co (II) to achieve a blue pigments; Mn (III) in the purple pigment; and two kind of white enamels were identified, i.e., tin oxide as an opacifier and uranium oxide. In addition, we established the reason for the poor state of conservation of some of the enamels by means of the identification of depolymerization and ion exchanges, well-known harmful effects of glass weathering, and finally a chronology was assigned for some of these pieces according to the enamel composition.

Description: Novel glass-ceramics with embedded thermoelectric Bi 2 Se 3 crystals were prepared from glass matrices in the Ge 20 Se 100− x Bi x ( x  = 5, 10, 12 mol%) system. Based on DSC results performed at different heating rates, characteristic activation energies ( E c ) and Avrami exponents ( n ) were obtained and analyzed by using Kissinger's relation, Ozawa's method, Augis–Bennett approximation and Matusita–Sakka theory. XRD results showed that pure Bi 2 Se 3 crystalline phase precipitated upon annealing at different temperatures for various time. The crystal size and crystalline fraction in the samples could be tuned by controlling the annealing time.

Description: In the present investigations nano size high alumina cements (HAC) were prepared by very effective co-melt precursor sintering technique from their metal nitrate precursors. The prime cementing phases observed were CA, CA 2 , and C 12 A 7 . The addition of nano structured cements in refractory castables has improved the thermo-chemical-mechanical properties to a significant extent. Each batch of low cement castables (LCC) was prepared from calcined Chinese bauxite, HAC, and superfine additives. The effect of HAC in bauxite castable with the additives similar to Silicon Carbide, reactive alumina, and micro-fine silica on the sinterability and properties of these castables was investigated. Physical properties such as apparent porosity and bulk density, mechanical properties such as hot modulus of rupture (HMOR), cold and hot modulus of rupture (CMOR), and cold crushing strength (CCS) of hydrated and sintered castables were studied. The sintered castables were also characterized for their solid phase compositions and microstructure using X-ray diffraction (XRD) and FE-SEM, respectively. In the castables new phases such as mullite, α-alumina were formed at the expense of bauxite and silica. Solid solution of mullite formed at high temperature acts as a bonding phase and is accounted for high HMOR, CMOR, and CCS values. These excellent properties of such castables may enable their uses in various applications such as refractory lining for fabrication of steel, aluminium, copper, glass, cement, chemicals, and ceramics.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Invasive pathogen - insect symbioses have been extensively studied in many different ecological niches. Whether the damage of symbioses in different introduced regions might be influenced by other microorganisms has, however, received little attention. Eight years of field data showed that the varied levels of the nematode and beetle populations and infested trees of the invasive Bursaphelenchus xylophilus-Monochamus alternatus symbiosis were correlated with patterns in the isolation frequencies of ophiostomatoid fungi at six sites, while the laboratory experiments showed that the nematode produced greater numbers of offspring with a female biased sex ratio and developed faster in the presence of one native symbiotic ophiostomatoid fungus Sporothrix sp.1. Diacetone alcohol (DAA) from xylem inoculated with Sporothrix sp.1 induced B. xylophilus to produce greater numbers of offspring. Its presence also significantly increased the growth and survival rate of M. alternatus, and possibly explains the prevalence of the nematode-vector symbiosis when Sporothrix sp.1 was dominant in the fungal communities. Studying the means by which multispecies interactions underlying biogeographical dynamics allowed us to better understanding the varied levels of damage caused by biological invasion across the invaded range.

Description: Zn 2 GeO 4 ceramic materials were synthesized by the solid-state method. Zn 2 GeO 4 powders were investigated with X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Oxygen defects in the Zn 2 GeO 4 ceramics were investigated by photoluminescence, Raman, and EDS spectra. Conductivity of Zn 2 GeO 4 was 0.18 S/cm at low temperature of 773 K, and its activation energy was 0.49 eV. The results showed that Zn 2 GeO 4 was a promising low-temperature electrolyte with high conductivity.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. In various terrestrial and aquatic ecosystems, predators affect resources indirectly via intermediate prey. Such indirect interactions involve reducing the density of the prey (density-mediated indirect interactions, DMIIs) or changing the behavioral, morphological or life history traits of the prey (trait-mediated indirect interactions, TMIIs). Although the importance of TMIIs has been highlighted recently, the strengths of both DMIIs and TMIIs under natural conditions have rarely been evaluated, especially in the context of resource community structure. We studied a three-level marine food chain involving the carnivorous snail Thais clavigera, its limpet prey Siphonaria sirius and the limpet's food sources, the algae Lithoderma sp. and Ulva sp. We measured the strengths of DMIIs and TMIIs and observed how the algal community changes under the pressure of natural predation by T. clavigera on S. sirius. Neither DMIIs nor TMIIs affected the total algal cover or chlorophyll content per unit area. However, both types of indirect interactions caused similar changes in algal composition by increasing the cover of Ulva and decreasing the cover of Lithoderma. This change in the algal community was caused by a reduction in the limpet's preferential consumption of the competitively dominant Ulva over Lithoderma. These results suggest that both DMIIs and TMIIs have similar effects on the changes in resource community structure under natural conditions.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Classifying the states of an individual and quantifying transitions between states is crucial while modeling animal behavior, movement and physiologic status. When these states are hidden or imperfectly known, it is particularly convenient to relate them to appropriate quantitative measurements taken on the individual. This task is however challenging when quantitative measurements are not available at each sampling occasion. For capture-recapture data, various ways of incorporating such non-discrete information have been used, but they are either ad hoc and/or use a fraction of the available information by relying on a priori thresholds to assign individual states. Here we propose to assign discrete states based on a continuous measurement and then model survival and transition probabilities based on these assignments. The main advantage of this new approach is that a more informative use of the non-discrete information is done. As an illustrative working example, we applied this approach to eco-epidemiological data collected accross a series of years and in which individuals of a long-lived seabird, the black-legged kittiwake (Rissa tridactyla), could either be visually detected or physically recaptured and blood sampled for subsequent immunological analyses. We discuss how this approach opens many perspectives in eco-epidemiology but also more broadly in population ecology.

Description: This article details the influence of zirconium doping on the piezoelectric properties and relaxor characteristics of 94( Bi 1/2 Na 1/2 ) TiO 3 –6 Ba ( Zr x Ti 1− x ) O 3 (BNT–6BZT) bulk ceramics. Neutron diffraction measurements of BNT–6BZT doped with 0%–15% Zr revealed an electric-field-induced transition of the average crystal structure from pseudo-cubic to rhombohedral/tetragonal symmetries across the entire compositional range. The addition of Zr up to 10% stabilizes this transition, resulting in saturated polarization hysteresis loops with a maximum polarization of 40 μC/cm 2 at 5.5 kV/mm, while corresponding strain hysteresis measurements yield a maximum strain of 0.3%. With further Zr addition, the ferroelectric order is progressively destabilized and typical relaxor characteristics such as double peaks in the current density loops are observed. In the strain hysteresis, this destabilization leads to an increase of the maximum strain by 0.05%. These changes to the physical behavior caused by Zr addition are consistent with a reduction of the transition temperature T F-R , above which the field-induced transformation from the relaxor to ferroelectric state becomes reversible.

Description: Precursor glasses for the ferroelectric barium bismuth titanate ( BaBi 4 Ti 4 O 15 ) (BBiT) have been prepared by the melt-quench technique in the SiO 2 – K 2 O – BaO – Bi 2 O 3 – TiO 2 (SKBBT) glass system with and without Eu 2 O 3 doping. BBiT glass–ceramic (GC) nanocomposites have been derived from these glasses by controlled heat treatment. The structural properties of the GCs have been investigated using X-ray diffraction (XRD), electron microscopy (FE-SEM, TEM), and FT-IR reflectance spectroscopy. FE-SEM images show the formation of randomly oriented hexagonal rod-shaped crystals of 200–400 nm and TEM images show 10–20 nm crystallites. FT-IR spectra exhibit the characteristic bands of BBiT at 480, 585, and 680 cm −1 . The activation energy of crystallization ( E c ) varies from 295 to 307 kJ/mol. The dielectric constants (ε r ) of glass and GC nanocomposites increase with an increase in frequency up to 3.0 MHz and then decrease up to 5.0 MHz. Heat-treated GCs show higher ε r values, in the range 25–55, compared to the precursor glasses (20–37). Dielectric losses (tan δ) for all the samples increase from 0.005 to 1.0 with an increase in frequency from 100 Hz to 5.0 MHz. Excitation spectra were recorded by monitoring emission at 613 nm corresponding to the 5 D 0 → 7 F 2 transition. An intense 466 nm excitation band corresponding to the 7 F 0 → 5 D 2 transition was observed. Emission spectra were then recorded by exciting the glass samples at 466 nm. Longer heat-treatment times led to a 15-fold increase in the intensity of the red emission at 612 nm, attributed to the segregation of Eu 3+ ions into the low phonon energy BBiT crystallites. The hardness (3.8–5.1 GPa) and fracture toughness (1.8–3.5 MPam 0.5 ) values obtained in the GCs are high and suitable for structural applications.

Description: Carbon doping is known to be very effective for enhancing the high-field properties of magnesium diboride, MgB 2 , but not for the low-field properties. Here, we report that both the high- and the low-field properties can be improved simultaneously without doping by increasing the initial magnesium partial pressure, by simply reducing the size of the magnesium particles. It is shown that in situ processed bulk MgB 2 sintered with fine magnesium powders has superior superconducting properties compared with a bulk sample fabricated using coarse magnesium lumps. The change in the lattice parameters was almost negligible; however, a clear increase in lattice strain can be observed for the sample sintered with fine magnesium powders. The increase in the lattice strain results in an enhancement of the high-field properties. Furthermore, it has also been found that the low-field critical current density is not reduced, but rather slightly increased for the fine magnesium powder sample. This is due to a closer linkage among the grains that drastically improves grain connectivity. These findings demonstrate that the initial growth mechanism of MgB 2 is very crucial for its superior superconducting properties, and it especially indicates the importance of magnesium vapor pressure.

Description: Revisiting classic phase diagrams and chemical phase relations in the solid state of a very well-studied oxide system, such as the lithium aluminosilicate (LAS) system, can open a new window for the design of new advanced materials with improved properties. Crystal chemistry and phase equilibria are used to demonstrate the ability to design materials with particular desired properties in the alumina-rich corner of the LAS phase diagram. The experimental results demonstrate the alumina and β-eucryptite solid-state compatibility.

Description: This work reports the crystallization, microstructure, and surface composition of Cu In 0.7 Ga 0.3 Se 2 (CIGS) thin films grown by femtosecond pulsed laser deposition at different annealing temperatures. The structural and optical properties of the CIGS films were characterized by X-ray diffraction, Raman scattering, UV-visible spectroscopy, and Hall effect measurement. The results indicate that binary crystals of CuS e initially formed on the as-deposited film, but then completely turned into a quaternary chalcopyrite structure after annealing at 400°C. Phase transformation significantly affects the surface morphology, Hall properties, and band gap. Transmission electron microscopy further revealed that an interface between the Mo substrate and CIGS crystallites contains an amorphous layer even at the high temperature of 500°C. For the application of photovoltaic devices, we also report on the photoresponse of both as-deposited and annealed films as demonstrated by preliminary tests.

Description: Reactive sintering of 3 Ti : Sn :2 C and 3Ti:Sn:2C:0.6Fe powder mixtures is studied in the temperature range 510°C–1200°C under argon. It is demonstrated that the recently discovered Ti 3 SnC 2 phase is formed, provided that Fe is added to a 3 Ti : Sn :2 C reactant mixture within the synthesis conditions used. Using dilatometric and X-Ray diffraction analyses, the formation mechanism of Ti 3 SnC 2 is discussed. Results show that at low temperature (about 510°C), tin is consumed to form Fe x Sn y intermetallics. At high temperature (about 1060°C), tin is newly available to form Ti 3 SnC 2 due to the melting of Fe x Sn y . Then, the intermediate phases, TiC and Ti 2 SnC , and/or Ti 5 Sn 3 , TiC , C , and Ti are dissolved in the ( Fe  +  Sn ) liquid phase and Ti 3 SnC 2 very likely precipitate from the melt. The second part of the study deals with the optimization of the Fe content in the initial 3Ti:Sn:2C reactant powder mixture to synthesize samples with larger Ti 3 SnC 2 content by hot isostatic pressing.

Description: The effects of non-stoichiometry on the microstructure, oxygen vacancies, and piezoelectric properties of ( Na 0.5 K 0.5 ) x NbO 3 (NK x N, where x  =   0.98, 1.00, 1.01, and 1.02) ceramics doped with sintering aid CuTa 2 O 6 (CT) doping were investigated. X-ray diffraction (XRD) patterns indicated that a secondary phase formed in CT-doped NK x N (NK x NCT) ceramics with x  〈   1.00 and that a pure phase was obtained with x  ≥   1.00. The grain size of NK x NCT ceramics increased with increasing x value due to the formation of a liquid phase. The internal bias field, activation energy, and Raman analysis for NK x NCT ceramics showed that the number of induced oxygen vacancies increased with decreasing x value. The high mechanical quality factor ( Q m ) value obtained for NK x NCT ceramics did not correspond to a higher concentration of oxygen vacancies, illustrating that the suitable compensation (excess Na and K ) is more important than the concentration of oxygen vacancies to obtain the ceramics with high Q m values. The NK x NCT ceramics with x  =   1.01 exhibited excellent piezoelectric properties, with k p and Q m values of 39.9% and 2,070, respectively.

Description: Low-temperature sintering of β-spodumene ceramics with low coefficient of thermal expansion (CTE) was attained using Li 2 O – GeO 2 sintering additive. Single-phase β-spodumene ceramics could be synthesized by heat treatment at 1000°C using highly pure and fine amorphous silica, α-alumina, and lithium carbonate powders mixture via the solid-state reaction route. The mixture was calcined at 950°C, finely pulverized, compacted, and finally sintered with or without the sintering additive at 800°C–1400°C for 2 h. The relative density reached 98% for the sample sintered with 3 mass% Li 2 O – GeO 2 additive at 1000°C. Its Young's modulus was 167 GPa and flexural strength was 115 MPa. Its CTE (from R.T. to 800°C) was 0.7 × 10 −6  K −1 and dielectric constant was 6.8 with loss tangent of 0.9% at 5 MHz. These properties were excellent or comparative compared with those previously reported for the samples sintered at around 1300°C–1400°C via melt-quenching routes. As a result, β-spodumene ceramics with single phase and sufficient properties were obtained at about 300°C lower sintering temperature by adding Li 2 O – GeO 2 sintering additive via the conventional solid-state reaction route. These results suggest that β-spodumene ceramics sintered with Li 2 O – GeO 2 sintering additive has a potential use as LTCC for multichip modules.

Description: Pyrochlore-structured lanthanide stannate ceramic ( Ln 2 Sn 2 O 7 ) has been synthesized via a new complex precipitation method. A suite of characterization techniques, including FTIR, Raman, X-ray, and electron diffraction as well as nitrogen sorption were employed to investigate the structural evolution of the synthesized and calcined powder. Raman, XRD, and selected area electron diffraction results confirm the presence of the pyrochlore structure after calcination of the powder above 1200°C. TEM imaging shows fine crystallites gradually increased in size from approximately 100 nm to about 500 nm with higher calcination temperatures. Grain growth and powder densification upon increasing the calcination temperature was confirmed by nitrogen sorption results. This aqueous synthetic method provides a simple pathway for the preparation of homogeneous lanthanide stannate ceramics.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Knowledge from basic plant ecology suggests that impact of one plant species on another is driven by either competition for the same limiting resources, or by unique plant traits. These processes might be context specific, explaining a differential impact of exotic plant invaders in the native vs. introduced range. With the help of a conceptual framework, we aimed at identifying the relationship between invader biomass and impact in the invasive Centaurea stoebe by conducting pairwise competition experiments with 15 European (old) and 15 North American (new) neighboring species. Old neighbors grew larger and could use available soil moisture more efficiently for growth than new neighbors. Interestingly, biomass of C. stoebe explained a substantial amount of the variation in biomass of the co-evolved neighbors, but not of the new "naïve" neighbors. Thus, impact in the home range appears to be driven by competition for the same limiting resources, but by other factors in the introduced range, possibly by exploitation of resources that are not used by the new neighbors or by interference competition. This distinction has important consequences for the management of invasive species; as in our study ecosystem recovery is less likely after simple biomass reduction.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. The giant panda (Ailuropoda melanoleuca) was taken to the brink of extinction in the 1980s through a combination of deforestation, large-scale loss of bamboo in the core of its range, poaching, and zoo collection, causing over 1,000 deaths from the 1950s. It was thought that the drastic population decline was likely to impose a severe impact on population viability. Here, based on temporal genotyping of individuals we show that this rapid decline did not significantly reduce the overall effective population size and genetic variation of this species, or of the two focal populations (Minshan and Qionglai) that declined the most. These results are contrary to previously assumptions, probably because the population decline has not produced the expected negative impact because of the short time scale involved (at most 10 generations), or because previous surveys underestimated the population size at the time of decline. However, if present-day habitat fragmentation and limited migration of giant pandas remains, we predict a loss of genetic diversity across the giant pandas' range in the near future. Thus, our findings highlight the substantial resilience of this species when facing demographic and environmental stochasticity, but key conservation strategies, such as enhancing habitat connectivity and habitat restoration should be immediately implemented to retain the extant genetic variation and maintain long-term evolutionary potential of this endangered species.

Description: Ceramics have played a crucial role in the development of fission based nuclear power, in glass & glass composite high level wasteforms, in composite cements to encapsulate intermediate level wastes (ILW) and also for oxide nuclear fuels based on UO 2 and PuO 2 /UO 2 mixed oxides. They are also used as porous filters with the ability to absorb radionuclides (RN) from air and liquids and are playing a key role in the cleanup at Fukushima. Non-oxides also find current fission applications including in graphite moderators and B 4 C control rods. Ceramics will continue to be significant in the near-term expansion of nuclear power via next-step developments of fuels with inert matrices or based on thoria and in wasteforms using alternative composite cements or single or multiphase ceramics that can host Pu & other difficult RN. Longer term advances for Generation IV reactors, which will operate at higher temperatures & with higher fuel burn-up require innovative fuel developments potentially via carbides & nitrides or composite fuel systems. Novel non-thermal (cement-like) and thermal techniques are currently being developed to treat some of the difficult legacy wastes. Non-thermally derived wasteforms developed from geopolymers, composite cements, hydroceramics, and phosphate-bonded ceramics and thermally derived wasteforms made by Hot Isostatic Pressing and fluidized bed steam reforming (FBSR) as well as vitrification techniques based on cold crucible melting (CCM), Joule-heater in-container melting and plasma melting (PM) are described. Future developments in waste treatment will be based on separation technologies for partitioning individual RN along with design & construction of RN-containing ceramic targets for inducing transmutation reactions. Near demonstration actinide-hosting ceramic wasteforms including multiphase Synroc systems are described. Opportunities also exist for ceramics in structural applications in Generation IV reactors such as composite SiC / SiC and C / C for fuel cladding and control rods and MAX phases and ultrahigh-temperature ceramics (UHTCs) may find near core fuel coating and cladding applications. Uses of ceramics in fusion reactor systems will be both functional (ceramic superconductors in magnet systems for plasma control and in Li silicate breeder blankets in tokamaks) and structural including as sapphire diagnostic windows, graphite diverters, and plasma facing C and UHTCs. In all these cases, performance is limited by poorly understood radiation damage and interface controlled processes, which demands a combined modeling/experimental approach.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Habitat loss can have a negative effect on the number, abundance, and composition of species in plant-pollinator communities. Although we have a general understanding of the negative consequences of habitat loss for biodiversity, much less is known about the resulting effects on the pattern of interactions in mutualistic networks. Ecological networks formed by mutualistic interactions often exhibit a highly nested architecture with low modularity, especially in comparison with antagonistic networks. These patterns of interaction are thought to confer stability on mutualistic communities. With the growing threat of environmental change, it is important to expand our understanding of the factors that affect biodiversity and the stability of the communities that provide critical ecosystem functions and services. We studied the effects of habitat loss on plant-pollinator network architecture and found that regional habitat loss contributes directly to species loss and indirectly to the re-organization of interspecific interactions in a local community. Networks became more highly connected and more modular with habitat loss. Species richness and abundance were the primary drivers of variation in network architecture, though species composition affected modularity. Theory suggests that an increase in modularity with habitat loss will threaten community stability, which may contribute to an extinction debt in communities already affected by habitat loss.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Landscape connectivity has been shown to alter community assembly and its consequences. Here we examine how strong, sudden changes in connectivity may affect community assembly by conducting experiments on the effects of 'community mixing', situations where previously-isolated communities become completely connected with consequent community re-organization. Previous theory indicates that assembly history dictates the outcome of mixing: mixing randomly-assembled communities leads to a final community with random representation from the original communities, while mixing communities that were assembled via a long history of colonizations and extinctions leads to strong asymmetry, with one community dominating the other. It also predicts that asymmetry should be stronger in the presence of predators in the system. We experimentally tested and explored this theory by mixing aquatic microcosms inhabited by a complex food web of heterotrophic protists, and algae. Our results confirm the prediction that long assembly history can produce asymmetry under mixing and suggest these dynamics could be important in natural systems. However, in contrast to previous theory we also found asymmetry weaker under mixing of communities with more complex trophic structure.

Description: The promotion of zircon ( ZrSiO 4 ) crystallization by ZnO from a zirconium-based frit glaze was studied and the possible mechanism was discussed. X-ray diffraction was used to analyze the relative quantities of zircon and other transitional crystals in the samples. The results show that ZnO can significantly decrease the crystallization temperature of zirconium-based glaze, depress the formation of Ca 2 ZrSi 4 O 12 , and promote the devitrification of transitional crystals t - ZrO 2 and Ca 2 ZnSi 2 O 7 , as well as lead to the formation of more zircon than the ZnO -free glaze. It was also found that zircon not only can form from the interaction between t - ZrO 2 and SiO 2 but also can devitrify directly from the glass phase of zirconium-based glaze.

Description: Barium-substituted CsAlSi 2 O 6 pollucites, Cs x Ba (1− x )/2 AlSi 2 O 6 , and barium- and iron-substituted pollucites, Cs x Ba (1− x )/2 Al x Fe 1− x Si 2 O 6 and Cs x Ba 1− x Al x Fe 1− x Si 2 O 6 were synthesized with 1 ≥  x ≥ 0.7 using a hydrothermal synthesis procedure. Rietveld analysis of X-ray diffraction data confirmed the substitution of Ba for Cs and Fe for Al , respectively. The crystallographic analysis also describes the effects of three different types of pollucite substitutions on the pollucite unit cell: Ba 2+ for Cs 1+ cation results in little effect on cell dimensions, intermediate concentrations of Ba 2+ and Fe 3+ substitution result in net minor expansion due to Fe 3+ addition, and large Ba and Fe substitutions result in overall framework contraction. Elemental analysis combined with microscopy further supports the phase purity of these new phases. These materials can be used to study the stability of CsAlSi 2 O 6 as a durable ceramic waste form, which could accommodate with time Cs and its decay product, Ba . Furthermore, success in iron substitution for aluminum into the pollucite lattice predicts that redox charge compensation for Cs cation decay is possible.

Description: Nitrogen-doped mullite fibers were first synthesized through the nitridation of Al 2 O 3 – SiO 2 gel fibers in NH 3 . The results showed that nitrogen take-up began at 800°C, reached the maximum at 900°C, and then decreased with increasing temperature. The ceramic fibers nitridated at 900°C were essentially amorphous, but contained a small amount of nano-sized Al – Si spinel crystals. Mullite was formed after nitridation at 1200°C, accompanied by crystallization of χ- SiAlON and δ- Al 2 O 3 . The incorporation of nitrogen resulted in the formation of a variety of nitrogen-containing crystalline phases. The grain size of the mullite fibers can be adjusted by changing of the nitrogen content.

Description: The solubility limit of Ca in 99.99% pure α- Al 2 O 3 (alumina) was measured using a wavelength dispersive spectrometer mounted on a scanning electron microscope. Al 2 O 3 samples were equilibrated at a concentration which ensured saturation of the Al 2 O 3 grains with Ca , and were quenched in water from 1600°C. The results were compared with those from samples which were furnace cooled from 1600°C. For the quenched samples, the Ca solubility limit was found to be 51 ± 1 ppm, which is significantly larger than the solubility limit for samples which were furnace cooled (26 ± 1 ppm).

Description: The possibility of developing large solid oxide fuel cell (SOFC) stacks based upon 25 cm 2 ceramic oxide anode-supported cells is investigated. Planar fuel cells comprising strontium titanate-based anode support impregnated with active catalysts were prepared using a combination of deposition techniques. The fuel cell tests performed in a semisealed rig have shown power densities of 185 mW cm −2 at 850°C using humidified hydrogen as fuel and air as oxidant. The structure and evolution of the catalytically active impregnated materials-10 mol% Gd -doped CeO 2 and nickel- are analysed using electron microscopy at the end of the fuel cell test, revealing that a ceria and nickel layer surrounds the titanate backbone grains while ~50–150 nm spherical-like nickel particles uniformly decorate this top layer.

Description: Structural and dielectric properties of (1− x ) BaTiO 3 – x Bi ( Mg 1/2 Ti 1/2 ) O 3 ( x  = 0.1–0.5) were investigated to understand the binary system and utilize it for high-voltage, high energy density capacitors. The solubility limit for Bi ( Mg 1/2 Ti 1/2 ) O 3 in a BaTiO 3 perovskite was between x  = 0.4 and x  = 0.5. A phase with pseudocubic symmetry was formed for x  = 0.1–0.4; a secondary phase developed at x  = 0.5. Dielectric measurements showed highly diffusive and dispersive relaxor-like characteristics from 10 to 40 mol% of Bi ( Mg 1/2 Ti 1/2 ) O 3 . These compositions also showed high relative permittivity with low-temperature coefficients of permittivity over a wide range of temperatures −100°C–600°C. Relaxation behavior was quantitatively investigated using the Vogel–Fulcher model, which revealed the activation energy of 0.17–0.22 eV. Prototyped multilayer capacitors of 18 mm × 17 mm × 4 mm dimensions with a capacitance of 12.5 nF at 1 kHz were successfully constructed and demonstrated multiple charge–discharge characteristics up to 10 kV.

Description: K 3 Gd ( PO 4 ) 2 : RE 3+ (RE = Eu, Tb) are prepared by solid-state reaction and their photoluminescence (PL) properties are investigated under UV and VUV excitation, respectively. The obtained experimental data show that no energy transfer happens among the activator ions Tb 3+ or Eu 3+ under UV excitation. Under 147-nm excitation, the strongest emission intensity of K 3 Gd ( PO 4 ) 2 : RE 3+ (RE = Eu, Tb) is obtained when the activator ions Tb 3+ or Eu 3+ concentration is 0.8 mol, the integrate emission intensity of K 3 Gd 0.2 (PO 4 ) 2 :0.8Tb 3+ is about 204% of commercial phosphor Zn 1.96 SiO 4 :0.04 Mn 2+ with chromaticity coordinates of (0.340, 0.561) and the decay time of about 5.09 ms under 147-nm excitation. We analyze the experimental data and propose a possible energy-transfer mechanism under 147-nm excitation.

Description: The 0.72 Bi ( Fe 1− x Al x ) O 3 –0.28 BaTiO 3 ( x  = 0, 0.01, 0.03, 0.05, and 0.07, abbreviated as BFA x – BT ) lead-free high-temperature ceramics were prepared by the conventional ceramic processing. Systematic investigation on the microstructures, crystalline structures, dielectric and piezoelectric properties, and high-temperature stability of piezoelectric properties was carried out. The crystalline structures of BFA x –BT ceramics evolve from rhombohedral structure with x 〈  0.01 to the coexistence of rhombohedral structure and pseudocubic phases with x  ≈ 0.01, finally to pseudocubic phases when x 〉  0.03. Remarkably high-temperature stability with near-zero temperature coefficient of piezoelectric properties ( TCk p ), together with improved piezoelectric properties has been achieved for x  = 0.01 BFA x –BT ceramics. The BFA x –BT( x  = 0.01) ceramics simultaneously show the excellent piezoelectric properties of d 33  = 151 pC/N, k p  = 0.31 and super-high-temperature stability of T d  = 420°C, TCk p  = 1 × 10 −4 . It is considered that the observed strong piezoelectricity and remarkably high-temperature stability should be ascribed to the phase coexistence of rhombohedral and pseudocubic phases. The rhombohedral phases have a positive TCk p value and the pseudocubic phases possess a negative TCk p value. Thus, the TCk p value of BFA x –BT ceramics can be tuned by composition of x .

Description: Ecology, Volume 0, Issue 0, Ahead of Print. When juveniles must tolerate harsh environments early in life, the disproportionate success of certain phenotypes across multiple early life stages will dramatically influence adult community composition and dynamics. In many species, large offspring have a higher tolerance for stressful environments than do smaller conspecifics (parental effects). However, we have a poor understanding of whether the benefits of increased parental investment carry over after juveniles escape harsh environments or progress to later life stages (latent effects). To investigate whether parental effects and the latent effects of stressful environments interactively influence offspring success, we determined the degree to which latent effects of harsh abiotic conditions are mediated by offspring size in two stony coral species. Larvae of both species were sorted by size class and exposed to relatively high temperature or low salinity conditions. Survivorship was quantified for six days in these stressful environments, after which surviving larvae were placed in ambient conditions and evaluated for their ability to settle and metamorphose. We subsequently assessed long-term post-settlement survival of one species in its natural environment. Following existing theory, we expected that within and between species, larger offspring would have a higher tolerance for harsh environmental conditions than smaller offspring. We found that large size did enhance offspring performance in each species. However, large offspring size within a species did not reduce the proportional, negative latent effects of harsh larval environments. Furthermore, the coral species that produces larger offspring was more, not less, prone to negative latent effects. We conclude that within species, larger offspring size does not increase resistance to latent effects. Comparing between species, we conclude that larger offspring size does not inherently confer greater robustness, and we instead propose that other life history characteristics such as larval duration better predict the tolerance of offspring to harsh and variable abiotic conditions. Additionally, when considering how stressful environments influence offspring performance, studies that evaluate only direct effects may miss crucial down-stream (latent) effects on juveniles that have significant consequences for long-term population dynamics.

Description: Ecology, Volume 94, Issue 2, Page 308-314, February 2013. Animal habitat selection is a process that functions at multiple, hierarchically structured spatial scales. Thus multi-scale analyses should be the basis for inferences about factors driving the habitat selection process. Vertebrate herbivores forage selectively on the basis of phytochemistry, but few studies have investigated the influence of selective foraging (i.e., fine-scale habitat selection) on habitat selection at larger scales. We tested the hypothesis that phytochemistry is integral to the habitat selection process for vertebrate herbivores. We predicted that habitats selected at three spatial scales would be characterized by higher nutrient concentrations and lower concentrations of plant secondary metabolites (PSMs) than unused habitats. We used the Greater Sage-Grouse (Centrocercus urophasianus), an avian herbivore with a seasonally specialized diet of sagebrush, to test our hypothesis. Sage-Grouse selected a habitat type (black sagebrush, Artemisia nova) with lower PSM concentrations than the alternative (Wyoming big sagebrush, A. tridentata wyomingensis). Within black sagebrush habitat, Sage-Grouse selected patches and individual plants within those patches that were higher in nutrient concentrations and lower in PSM concentrations than those not used. Our results provide the first evidence for multi-scale habitat selection by an avian herbivore on the basis of phytochemistry, and they suggest that phytochemistry may be a fundamental driver of habitat selection for vertebrate herbivores.

Description: Ecology, Volume 94, Issue 2, Page 336-345, February 2013. Identifying the relative contributions of genetic, maternal, and environmental factors to phenotypic variation is critical for evaluating the evolutionary potential of fitness-related traits. We employed a novel two-step cross-fostering experiment to quantify the relative contributions of clutch (i.e., maternal identity) and maternally chosen nest sites to phenotypic variation during three early life stages (incubation, hibernation, dispersal) of the painted turtle (Chrysemys picta). By translocating eggs between nests in the field, we demonstrated that both clutch and nest site contribute to phenotypic variation at hatching. Because hatchling C. picta hibernate inside nests, we performed a second cross-foster to decouple the effects of the incubation nest with that of the hibernation nest. Incubation nest explained little variation in phenotypes at spring emergence, but winter nest site was important. We found no evidence that mothers select nest sites specific to reaction norms of their own offspring, suggesting that females may select nest sites with microhabitats that broadly meet similar requirements across the population. After hibernation, we released hatchlings to assess performance and phenotypic selection during dispersal. Hibernation nest site influenced physiological performance during dispersal, and we detected nonlinear selection on hatchling carapace length. Our experiment demonstrates that nest-site choice has substantial effects on phenotypic variation and fitness across multiple early life stages.

Description: Ecology, Volume 94, Issue 2, Page 356-367, February 2013. Purposeful species introductions offer opportunities to inform our understanding of both invasion success and conservation hurdles. We evaluated factors determining the energetic limitations of brown trout (Salmo trutta) in both their native and introduced ranges. Our focus was on brown trout because they are nearly globally distributed, considered one of the world's worst invaders, yet imperiled in much of their native habitat. We synthesized and compared data describing temperature regime, diet, growth, and maximum body size across multiple spatial and temporal scales, from country (both exotic and native habitats) and major geographic area (MGA) to rivers and years within MGA. Using these data as inputs, we next used bioenergetic efficiency (BioEff), a relative scalar representing a realized percentage of maximum possible consumption (0–100%) as our primary response variable and a multi-scale, nested, mixed statistical model (GLIMMIX) to evaluate variation among and within spatial scales and as a function of density and elevation. MGA and year (the residual) explained the greatest proportion of variance in BioEff. Temperature varied widely among MGA and was a strong driver of variation in BioEff. We observed surprisingly little variation in the diet of brown trout, except the overwhelming influence of the switch to piscivory observed only in exotic MGA. We observed only a weak signal of density-dependent effects on BioEff; however, BioEff remained 2.5 fish/m2. The trajectory of BioEff across the life span of the fish elucidated the substantial variation in performance among MGAs; the maximum body size attained by brown trout was consistently below 400 mm in native habitat but reached ∼600 mm outside their native range, where brown trout grew rapidly, feeding in part on naive prey fishes. The integrative, physiological approach, in combination with the intercontinental and comparative nature of our study, allowed us to overcome challenges associated with context-dependent variation in determining invasion success. Overall our results indicate “growth plasticity across the life span” was important for facilitating invasion, and should be added to lists of factors characterizing successful invaders.

Description: Ecology, Volume 94, Issue 2, Page 489-498, February 2013. Increasing evidence shows that spatial interactions between sedentary organisms can structure communities and promote landscape complexity in many ecosystems. Here we tested the hypothesis that reef-forming mussels (Mytilus edulis L.), a dominant intertidal ecosystem engineer in the Wadden Sea, promote abundances of the burrowing bivalve Cerastoderma edule L. (cockle) in neighboring habitats at relatively long distances coastward from mussel beds. Field surveys within and around three mussel beds showed a peak in cockle densities at 50–100 m toward the coast from the mussel bed, while cockle abundances elsewhere in the study area were very low. Field transplantation of cockles showed higher survival of young cockles (2–3 years old) and increased spat fall coastward of the mussel bed compared to within the bed and to areas without mussels, whereas growth decreased within and coastward of the mussel bed. Our measurements suggest that the observed spatial patterns in cockle numbers resulted from (1) inhibition effects by the mussels close to the beds due to preemptive algal depletion and deteriorated sediment conditions and (2) facilitation effects by the mussels farther away from the beds due to reduction of wave energy. Our results imply that these spatial, scale-dependent interactions between reef-forming ecosystem engineers and surrounding communities of sedentary benthic organisms can be an important determinant of the large-scale community structure in intertidal ecosystems. Understanding this interplay between neighboring communities of sedentary species is therefore essential for effective conservation and restoration of soft-bottom intertidal communities.

Description: Owing to the widespread presence of electromagnetic interferences, it is necessary to develop new materials with excellent high-temperature electromagnetic wave (EM) absorption properties. In the present work, ZnO is infiltrated into porous ZrSiO 4 substrates to form ZnO / ZrSiO 4 composite ceramics using sol-gel process. The doping of aluminum results in the improvement of electrical conductivity and the significant change in the morphology of ZnO . With the increase in environment temperature during measurement, the permittivity of the composite ceramics increases first and then decreases dramatically, which is attributed to the change in conductive loss. The electrical conductivity increases with increasing measurement temperature. However, the concentration of oxygen vacancies decreases under air atmosphere when the measurement temperature increases continuously, which results in the reduction in conductivity. Therefore, permittivities of the undoped and doped ceramics measured at 673 K are higher than the ones at the other temperatures. The composite ceramics maintain a relatively high EM absorption coefficient, low reflection coefficient (RC), and wide effective absorption bandwidth at environment temperatures up to 773 K. As a result, we conclude that the ZnO / ZrSiO 4 composite ceramics exhibit a promising prospect as a kind of high-temperature EM absorbing material.

Description: [0001] textured alumina ceramics with a fine grain size were fabricated between 1400°C and 1600°C via templated grain growth (TGG) using fine alumina platelets (~0.6 and ~3 μm diameter) aligned by tape casting in either a 50 nm α- Al 2 O 3 matrix powder, or in a seeded boehmite sol. The 3 μm templates could be readily aligned by tape casting in both matrices (orientation parameters r  = 0.27 and 0.18, respectively), whereas 0.6 μm diameter templates were well aligned in the seeded boehmite sol only ( r  = 0.29). Improved alignment in boehmite sols is attributed to inorganic gelation, resulting in a strongly pseudo-plastic rheology that preserves template alignment against the influence of Brownian motion. The in situ formation of fine α- Al 2 O 3 matrix after transformation in the seeded boehmite system results in a higher driving force for TGG and improves texture development. The combination of 3 μm templates with a seeded boehmite matrix results in extremely high texture qualities (texture fraction f  = 0.97–0.99, r  = 0.17) while maintaining a relatively fine grain size (5–10 μm in diameter and 1.5–3 μm in thickness). Although undoped samples can be fully textured at 1600°C, adding as little as ~0.25 wt% CaO / SiO 2 dopant improves TGG kinetics and yields full texture at 1400°C.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Facilitation cascades are critical to the maintenance of biodiversity in a variety of habitats. Using two experiments, we examined how the morphological traits and density of interacting foundation species influence the establishment and persistence of a facilitation cascade in temperate Australian mangrove forests. In this system, mangrove pneumatophores trap the free living alga, Hormosira banksii, which in turn supports dense and diverse assemblages of epifaunal molluscs. The first experiment, manipulating pneumatophore height and density, revealed that these two traits each had additive negative effects on the establishment, but additive positive effects on the persistence of the cascade. High densities of tall pneumatophores initially served as a physical barrier to algal colonization of pneumatophore plots, but over the longer term enhanced the retention of algae, the increased algal biomass in turn facilitating epifaunal colonization. The second experiment demonstrated that the retention of algae by pneumatophores was influenced more by algal thallus length than vesicle diameter, and this effect occurred independent of pneumatophore height. Our study has extended facilitation theory by showing that the morphological traits and density of basal and intermediary facilitators influence both the establishment and persistence of facilitation cascades. Hence, attempts to use foundation species as a tool for restoration will require an understanding not only of the interactions among these, but also of the key traits that modify inter-relationships.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Habitat selection is a fundamental aspect of animal ecology, the understanding of which is critical to management and conservation. Global positioning system data from animals allow fine-scale assessments of habitat selection and typically are analyzed in a use-availability framework, whereby animal locations are contrasted with random locations (the availability sample). Although most use-availability methods are in fact spatial point process models, they often are fit using logistic regression. This framework offers numerous methodological challenges, for which the literature provides little guidance. Specifically, the size and spatial extent of the availability sample influences coefficient estimates potentially causing interpretational bias. We examined the influence of availability on statistical inference through simulations and analysis of serially correlated mule deer GPS data. Bias in estimates arose from incorrectly assessing and sampling the spatial extent of availability. Spatial autocorrelation in covariates, which is common for landscape characteristics, exacerbated the error in availability sampling leading to increased bias. These results have strong implications for habitat selection analyses using GPS data, which are increasingly prevalent in the literature. We recommend researchers assess the sensitivity of their results to their availability sample and, where bias is likely, take care with interpretations and use cross validation to assess robustness.

Description: Yttria partially stabilized zirconia Y-PSZ/glass-ceramic composites were prepared by reaction sintering using powder mixtures of a SiO 2 – Al 2 O 3 – ZnO – CaO – ZrO 2 – TiO 2 -based glass and yttria partially stabilized zirconia (Y-PSZ). The glass crystallized during sintering at temperatures of 1173, 1273, and 1373 K to give a glass-ceramic matrix for high-temperature protecting coatings. With the increasing firing time, the added zirconia reacted with the base glass and a glass-ceramic material with dispersed zircon particles was prepared in situ . Furthermore, the added zirconia changed the crystallization behavior of the base glass, affecting the shape, amount, and distribution of zircon in the microstructure. The bipyramid-like zircon grains with imbedded residual zirconia particles turned out to have two growth mechanisms: the inward growth and the outward growth, and its rapid growth was mainly dominated by the later one. For comparison, the referenced glass-ceramic was prepared by sintering using exclusive glass granules and its crystallization behavior at 1173–1373 K was examined as well. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to characterize the crystallization behavior of the base glass and the phase evolution of the Y-PSZ/glass-ceramic composites.

Description: In this study, we present the preparation of a bulk material with a composition of 80 GeTe 2 –20 Ga 2 Te 3 by combining mechanosynthesis and sintering. This composition cannot be prepared by conventional melt/quenching technique. The progressive evolution of the powder during ball-milling is followed by X-ray Diffraction (XRD) and Differential Scanning Calorimetry analysis. The final powder obtained is highly crystalline, but a glass transition temperature ( T g ) is observed, indicating the presence of some amorphous phase remaining, allowing for its efficient sintering. By hot-pressing, a dense bulk material with a fine microstructure and a high electrical conductivity is obtained. The synthesis method described represents a simple and cost-effective way to produce tellurium-based materials of desired dimension with potential applications for optical storage or thermoelectric devices.

Description: Revealing and understanding the microscopic origins of the macroscopic properties of aluminosilicate glasses is important for the design of new glasses with optimized properties. In this work, we study the composition-structure-property relationships in 20 MgO / CaO sodium aluminosilicate glasses upon Al 2 O 3 -for- SiO 2 and MgO -for- CaO substitutions. We find that some properties (density, molar volume, Young's modulus, and shear modulus) are linear through the investigated range of Al 2 O 3 compositions, while others (refractive index, coefficient of thermal expansion, Vickers hardness, isokom temperatures, and liquid fragility index) exhibit a change in the slope around the composition with [ Al 2 O 3 ] = [ Na 2 O ], which is especially pronounced for the glasses containing MgO . We discuss these phenomena based on structural information obtained by NMR spectroscopy and topological considerations.

Description: In this article the changes on the surface of the 45S5 bioglass submitted to an enrichment with calcium ions were investigated. The method employed was the immersion of bioglass in calcium molten salt bath at 450°C. Changes in composition were probed by different techniques of chemical analysis. The use of SEM-EDS allowed estimating the thickness modified, as being about 10 μm. X-ray photoelectron spectroscopy enabled to infer over the structural changes on the surface of 45S5 bioactive glass. The entry of calcium in the vitreous network promoted the phase separation of microdomains rich in silica and phosphate on the surface of the glass. The formation of immiscibility region was attributed a depolymerization of silica network and also, to a possible migration of phosphate species from the bulk. The results of this study indicate a great change in the surface properties of this biomaterial. In addition, the method proposed in this study proved to be very promising in the possibility of designing the surface of bioactive glasses, to modulate the desired properties, keeping the bulk unchanged.

Description: Ecology, Volume 94, Issue 2, Page 346-355, February 2013. Hydrogen stable isotope ratios of keratin (δ2HK) are increasingly used as endogenous markers to study animal movements, yet it is unclear what factors might influence δ2HK in free-ranging animals. We studied hydrogen stable isotope ratios of body water (δ2HBW) and fur keratin in 36 bat species (〉400 individuals) from a tropical forest assemblage to evaluate if δ2HBW and δ2HK are related to body size, trophic position, and movement ecology. We found a relatively large range of δ2HBW values (∼65‰) across bat species. Our phylogenetically controlled analysis showed that δ2HBW was not related to body size, trophic position, or movement ecology of species. The analysis also indicated that δ2HBW of primary consumers (i.e., fruit-eating bats) was similar to that of fruit juice, and δ2HBW of secondary consumers (i.e., animalivorous bats) was similar to that of surface water. Across bat species, δ2HK tended to decrease with increasing δ2HBW, suggesting that δ2HK is not directly linked to δ2HBW. We further tested whether δ2HK varied with a species' trophic position (measured as δ15N) and movement ecology (local or regional species). In syntopic bats, δ2HK ranged over 73‰, yet δ2HK was related neither to δ15N nor to the movement ecology of species. Fur keratin of secondary consumers was more enriched in 2H by 44‰ and in 15N by 3.7‰ compared with fur keratin of primary consumers. In an intraspecific analysis, we found that δ2HK of an insectivorous bat varied by 20‰ between colonies at 4 km distance. Within this species, δ2HK was not related to individual δ15N and body mass. Our data suggest that variation in δ2HK can be large in bats of tropical assemblages, both across species (range ∼70‰) and even within sedentary species (range ∼20‰), and that δ2HK is largely affected by the dietary habits of species.

Description: Ecology, Volume 94, Issue 2, Page 389-402, February 2013. Although recent climatic warming has markedly increased fire activity in many biomes, this trend is spatially heterogeneous. Understanding the patterns and controls of this heterogeneity is important for anticipating future fire regime shifts at regional scales and for developing land management policies. To assess climatic and land cover controls on boreal forest fire regimes, we conducted macroscopic-charcoal analysis of sediment cores and GIS analysis of landscape variation in south-central Alaska, USA. Results reveal that fire occurrence was highly variable both spatially and temporally over the past seven millennia. At two of four sites, the lack of distinct charcoal peaks throughout much of this period suggests the absence of large local fires, attributed to abundant water bodies in the surrounding landscape that have likely functioned as firebreaks to limit fire spread. In contrast, distinct charcoal peaks suggest numerous local fires at the other two sites where water bodies are less abundant. In periods of the records where robust charcoal peaks allow identification of local-fire events over the past 7000 years, mean fire return intervals varied widely with a range of 138–453 years. Furthermore, the temporal trajectories of local-fire frequency differed greatly among sites and were statistically independent. Inferred biomass burning and mean summer temperature in the region were not significantly correlated prior to 3000 years ago but became positively related subsequently with varying correlation strengths. Climatic variability associated with the Medieval Climate Anomaly and the Little Ice Age, along with the expansion of flammable Picea mariana forests, probably have heightened the sensitivity of forest burning to summer temperature variations over the past three millennia. These results elucidate the patterns and controls of boreal fire regime dynamics over a broad range of spatiotemporal scales, and they imply that anthropogenic climatic warming and associated land cover changes, in particular lake drying, will interact to affect boreal forest burning over the coming decades.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. The magnitude and direction of biological effects of environmental disturbances can vary considerably, especially among studies that use presence/absence manipulations. Because non-linearities (e.g., humped relationships) are common in biological systems, this heterogeneity in effects may arise if systems are similar in their responses but specific studies use few (e.g., two) levels, or a narrow range, of a factor. To test whether nonlinearity can explain heterogeneous responses to a common environmental disturbance, I examined the effect of nutrient enrichment on coral growth, which has been previously shown using simple (e.g., 2-level) manipulations to yield positive, negative, or neutral responses. I subjected corals (Porites) to a nutrient gradient in situ for 28 days. Coral growth rate increased (2.4 fold) then decreased (2.7 fold) with enrichment, returning to near-ambient values at the highest nutrient levels. This unimodal response could explain disparities among past findings and provides a compelling case for using regression designs to understand heterogeneity within ecological interactions.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Vertical heterogeneity in the physical characteristics of lakes and oceans is ecologically salient and exploited by a wide range of taxa through diel vertical migration to enhance their growth and survival. Whether analogous behaviors exploit longitudinal habitat heterogeneity in streams is largely unknown. Here we document cyclic horizontal movements at daily time scales in a stream-dwelling fish. Juvenile coho salmon made feeding forays into cold habitats with abundant food, and then moved long distances (350-1300 m) to warmer habitats to accelerate metabolism and increase their assimilative capacity. This behavioral thermoregulation enabled fish to mitigate trade-offs between trophic and thermal resources by exploiting thermal heterogeneity. Fish that exploited thermal heterogeneity grew at substantially faster rates than individuals that assumed other behaviors. Our results provide empirical support for the importance of thermal diversity in lotic systems, and emphasize the importance of considering interactions between animal behavior and habitat heterogeneity when restoring ecosystems.

Description: Lanthanum hexaaluminate is a promising competitor to establish yttria partially stabilized zirconia as a thermal barrier coating material for Ni -based superalloy due to its relative low intrinsic thermal conductivity and low sinterability at temperatures exceeding 1100°C. Sr 2+ and Ti 4+ were selected as two dopants to partially substitute the La 3+ and Al 3+ in LaMgAl 11 O 19 , respectively. The variation in thermal conductivity with Sr 2+ and Ti 4+ fractions was analyzed based on structure information provided by X-ray diffraction and Raman spectroscopy. The average crystal size of LaMgAl 11 O 19 sintered at 1600°C for 10 min by spark plasma sintering is in nanoscale. The fully dense La 1− x Sr x MgAl 11− x Ti x O 19 solid solution showed a minimum thermal conductivity value (λ = 1.12 W/(m K) −1 , T  = 1273 K) at the composition of La 0.5 Sr 0.5 MgAl 10.5 Ti 0.5 O 19 ,which possibly reduces from the enhanced phonon scattering due to mass and strain fluctuations at the Ln 3+ and B 3+ sites.

Description: Aqueous 3Y-TZP inks with solid contents of 22 and 27 vol% were used for fabricating three-dimensional ceramic components by the direct ink-jet printing process (DIP). The DIP fabrication was realized using a thermal ink-jet (TIJ) printing system. Despite the different physical properties of the inks, both inks were successfully ejected and deposited. To define the optimum window of the ink properties required for a stable printing operation, both ceramic inks as well as a typical TIJ ink were characterized in terms of particle size distribution, zeta potential, viscosity, surface tension, and the inverse Ohnesorge number ( Oh −1 ). Moreover, single drops of all inks were deposited and analyzed by scanning electron microscopy (SEM) to examine the form and integrity of the ejected drops. Demonstration objects (a base with curved channels and a sample molar tooth) were DIP fabricated using both of the ceramic inks. These objects show the potentials of the DIP process for ceramics manufacturing particularly by using TIJ printing systems.

Description: Spherical granules of aluminum nitride (AlN) with an average particle size of about 50 μm were produced from aqueous suspensions using an AlN powder surface treated against hydrolysis with aluminum dihydrogenphosphate [Al(H 2 PO 4 ) 3 ]. Two different amounts of Al(H 2 PO 4 ) 3 were tested and the effects of surface treatment and aging time were evaluated by various techniques (XRD, TG-DTA, zeta potential and pH measurements). The treated powder exhibited antihydrolytic property and good dispersing behavior, enabling the preparation of low-viscosity and high-concentration aqueous AlN slurries for freeze granulation. The spherical AlN granules were sintered in a boron nitride (BN) powder bed followed by ultrasonic washing of the AlN granulates/BN mixture to remove BN. The sintered spherical AlN granules present excellent crystallinity and high sphericity as observed from SEM micrographs.

Description: Near-infrared (NIR) quantum cutting involving the emission of two NIR photons for each visible photon absorbed is realized from Eu 2+ /Yb 3+ codoped chalcohalide glasses. Excitation, emission and decay spectra are measured to prove the occurrence of cooperative energy transfer (ET) from Eu 2+ to Yb 3+ . The maximum ET efficiency obtained is as high as 85%. The ET from Eu 2+ to Yb 3+ is followed by dipole-dipole interaction. The possible mechanism of ET is discussed.

Description: Well-crystallized pure BiFeO 3 nanopowders were successfully synthesized at the temperature as low as 120°C by an ethanol-assisted hydrothermal process. In this synthesis, the composition of the solvent played important roles in the formation of pure BiFeO 3 . The BiFeO 3 nanopowders synthesized with 4:3 ethanol/water ratio mainly consists of cubic structures with size from 50 to 150 nm. Zero-field-cooled (ZFC) and field-cooled (FC) magnetization measurements indicated that pure BiFeO 3 nanopowders showed a spin-glass transition below the freezing temperature. Moreover, the BiFeO 3 nanopowders exhibited ferromagnetic order at room temperature.

Description: Nanoparticles of Co 0.6 Zn 0.4 Fe 2 O 4 , with narrow size distribution, regular morphology, and high saturation magnetization, have been synthesized. The synthesis, involved a very rapid mixing of reducible metal cations with sodium borohydride, is carried out in a colloid mill and followed by a separate hydrothermal process. The microstructure and magnetic properties of the synthesized nanoparticles are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). The effects of different synthesis conditions (synthesis temperature and reaction time) on the characteristics of the ferrite nanoparticles are discussed. The changes in cation contribution are revealed by the Raman study. The magnetic measurements explore that all the as-synthesized samples are superparamagnetic in nature. The corresponding superparamagnetic behavior is explained by paramagnetic Langevin theory. Note that, the superparamagnetic Co 0.6 Zn 0.4 Fe 2 O 4 ferrite nanoparticle, with excellent performance, can be synthesized at 160°C for a short reaction time (4 h).

Description: We show that multilayer green tapes constituted from sandwiched layers of NiO–zirconia anode and cubic zirconia electrolyte can be sintered below 1000°C in a few seconds under the influence of a DC electric field. The sintering yields a dense electrolyte layer with minor closed porosity, and an anode layer with open porosity, and, most importantly, a multilayer that is largely devoid of defects and delamination.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. The relative importance of species richness and identity for the diversity-function relationship remains controversial. We mechanistically explored the potential contribution of ecosystem processes complexity (EPC) (i.e., the number of pathways and mechanisms through which an ecosystem process can be directly and/or indirectly affected by species and/or their interactions) to the resolution of this controversy. We hypothesized that the complementarity effects of biodiversity will be stronger and that the diversity-function relationship will be more dependent on species richness as the EPC increases. Using a benthic bioturbator community as a model system we tested these predictions across ecosystem processes that could be ordered according to their complexity (suspended material flux 〈 PO4-P flux 〈 NH4-N flux 〈 bacterioplankton production). Consistent with our predictions, species richness explained an increasing proportion of data variation as EPC increased, whereas the contrary was observed for species composition. Nontransgressive overyielding was not affected by EPC, but the magnitude of transgressive overyielding increased significantly with EPC, indicating that complementarity may be stronger as EPC increases. Our results highlight the importance of considering the interactive role of the characteristics of ecosystem processes in our theoretical understanding of the diversity-function relationship and its underlying mechanisms.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Why are plant species found in certain locations and not in others? The study of community assembly rules has attempted to answer this question, and many studies articulate around the historic dichotomy of deterministic (predictable niches) vs. stochastic (random or semi-random processes). The study of successional sequences to determine whether they converge, as would be expected by deterministic theory, or diverge, as a stochastic theory would suggest, has been one method used to investigate this question. In this article we ask the question: do similar boreal bryophyte communities develop in the similar habitat created by convergent succession after fires of different severities? Or do the stochastic processes generated by these two types of fires lead to different communities? Specifically we predict that deterministic structure will be more important for large forest floor species than stochastic process, and that the inverse will be true for small bryophyte species. We used multivariate regression trees and model selection to determine the relative weight of structure (forest structure, substrates, soil structure) and processes (fire severity) for the two groups of bryophyte species sampled in thirteen sites (seven high severity and five low severity). Contrary to our first hypothesis, processes were as important for large forest floor bryophytes as for small pocket species. Fire severity, its interaction with the quality of available habitat, and its impact on the creation of biological legacies played dominant roles in determining community structure. In this study sites with nearly identical forest structure, generated via convergent succession after high and low severity fire were compared to see whether these sites supported similar bryophyte communities. While similar to some degree, both the large forest floor species and the pocket species differed after high compared to low severity fire. This result suggests that the "how", or process of habitat generation, influences community composition in this system and that a snapshot of habitat conditions taken at only one point in time is insufficient to explain species distribution.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. For decades, ecologists have been testing for species saturation by using regression analysis to determine the relationship between local and regional species richness. The cumulative result of scores of studies and meta-analyses has led to a general consensus that evidence of species saturation is relatively uncommon. However, the bias induced on the regression by the arbitrary choice of local and regional area has threatened to undermine this consensus and has even led to the proposal to abandon the regression method entirely. Nonetheless, the use of regression analysis to determine local-regional richness relationships continues. We performed a meta-analysis of almost 100 datasets using a logratio-based regression model that is free of the scale-induced bias inherent in more commonly used models. This reanalysis contradicts the general consensus: saturated relationships are at least as common as unsaturated patterns. However, a discouragingly large proportion of studies produce no discernable patterns at all. An explanation for such a plethora of species saturation patterns poses a challenge to our understanding of the processes that govern community assembly.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. This study examines influences of climate variability on spruce beetle (Dendroctonus rufipennis) outbreak across NW Colorado during the CE 1650-2011 period. Periods of broad-scale outbreak reconstructed using documentary records and tree-rings were dated to 1843 to 1860, 1882-1889, 1931-1957, and 2004-2010. Periods of outbreak were compared with seasonal temperature, precipitation, vapor pressure deficit (VPD), the Palmer Drought Severity Index (PDSI), and indices of ocean-atmosphere oscillation that include the El Niño Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and Atlantic Multidecadal Oscillation (AMO). Classification trees showed that outbreaks can be predicted most successfully from above average annual AMO values and above average summer VPD values, indicators of drought across Colorado. Notably, we find that spruce beetle outbreaks appear to be predicted best by interannual to multidecadal variability in drought, not by temperature alone. This finding may imply that spruce beetle outbreaks are triggered by decreases in host tree defenses, which are hypothesized to occur with drought stress. Given the persistence of the AMO, the shift to a positive AMO phase in the late 1990s is likely to promote continued spruce beetle disturbance.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Theory predicts that animals breeding in heterogeneous landscapes preferentially occupy habitats likely to maximize individual fitness, but identifying those habitats has proved problematic. Many studies develop metrics of habitat quality linked to site-specific reproductive output measured in successive years, but few separate the independent effects of individual 'intrinsic quality' from those due solely to the attributes of the habitats themselves. In many populations, processes such as competitive territory defense, longevity, site-fidelity, and variation in breeding density and territory size over time have the potential to limit the degree to which individual and habitat quality will be positively related in nature. However, the effects of these processes on estimates of habitat or site-specific reproductive output have not been thoroughly investigated. We show that female song sparrows (Melospiza melodia) nested preferentially in breeding sites with high mean reproductive output assessed over 35 years and that variation in site-specific reproductive output was positively related to female intrinsic quality, measured here as the lifetime reproductive success of individual females relative to others hatched the same year (rLRS). In contrast, vegetation traits (shrub cover, edge and soil depth) predicted female preference for breeding sites but not site-specific variation in annual reproductive output. Female quality also did not predict which females occupied more- or less-preferred breeding sites over the study period. However, mean annual reproductive output of breeding sites estimated over 35 years was strongly, positively related to the quality of the females that nested in them. Overall, these results indicate that site-specific estimates of habitat quality that do not consider the quality of the individuals occupying those sites may include substantial bias due to variation in occupant quality, and thus may not reliably predict the intrinsic effects of habitat quality on individual or population fitness.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Forest die-off caused by mountain pine beetle (MPB) is rapidly transforming western North American landscapes. The rapid and widespread death of lodgepole pine will likely have cascading effects on biodiversity. One group particularly prone to such declines associated with MPB are ectomycorrhizal fungi, symbiotic organisms that can depend on pine for their survival, and are critical for stand regeneration. We evaluated the indirect effects of MPB on above- (community composition of epigeous sporocarps) and belowground (hyphal abundance) occurrences of ectomycorrhizal fungi across 11 forest stands. Along a gradient of mortality (0-82% pine killed), macromycete community composition changed; this shift was driven by a decrease in the species richness of ectomycorrhizal fungi. Both the proportion of species that were ectomycorrhizal and hyphal length in the soil declined with increased MPB-caused pine mortality; less than 10% of sporocarp species were ectomycorrhizal in stands with high pine mortality compared with greater than 70% in stands without MPB attacks. The rapid range expansion of a native insect results not only in the widespread mortality of an ecologically and economically important pine species, but the effect of MPB may also be exacerbated by the concomitant decline of fungi crucial for recovery of these forests.

Description: Ecology, Volume 94, Issue 9, Page 2110, September 2013. Abstract Expert collection of specimens in the field and further determination of species is the best method for determining species richness. However, the relative paucity of botanists working in Antarctica makes this approach impractical for broad-scale surveys of Antarctic floral biodiversity. Lichens are the dominant macrophytes of terrestrial Antarctica and, as such, play a fundamental part of the ice-free terrestrial ecosystem. Many distinct ice-free terrestrial habitats in the Antarctic are not represented in the current network of Antarctic protected areas. However, it is difficult to identify appropriate areas for conservation because comprehensive data on distributional patterns of Antarctic flora are not available, and existing data for most Antarctic lichen species are not compiled. Consequently, cost-effective survey methods and surrogates for the prediction of species richness are needed to accelerate assessments of local biodiversity and help select areas for conservation. A combination of a photographic “citizen scientist” approach for the collection of data and the use of parataxonomic unit (PU) richness as a surrogate for species richness, might be a possible solution to effectively collect preliminary information and rapidly build databases on species diversity. We have developed a database and gathered photographic information on lichen occurrences for sites that are frequently visited by tourists. We tested the identification capabilities with a reference data set of Antarctic lichen images from the U.S. National Herbarium. We showed that all species used in this test can be detected and that, for 74% of the images, all classifiers were able to identify the genus of the specimen. Twenty-nine sites were photographically surveyed by researchers and tourists between 2009/2010 and 2011/2012 in the Antarctic Peninsula region. We estimated PU richness as a proxy for species richness for each of the 29 sites surveyed and provide two examples of potential applications. These surveys provide preliminary information for identifying areas for protection and priorities for future research.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Human activities that involve land-use change often cause major transformations to community and ecosystem properties both aboveground and belowground, and when land use is abandoned, these modifications can persist for extended periods. However, the mechanisms responsible for rapid recovery versus long-term maintenance of ecosystem changes following abandonment remain poorly understood. Here, we examined the long-term ecological effects of two remote former settlements, regularly visited for ~300 y by reindeer-herding Sami and abandoned ~100 y ago, within an old-growth boreal forest that is considered one of the most pristine regions in northern Scandinavia. These human legacies were assessed through measurements of abiotic and biotic soil properties and vegetation characteristics at the settlement sites and at varying distances from them. Low-intensity land-use by Sami is characterized by the transfer of organic matter towards the settlements by humans and reindeer herds, compaction of soil through trampling, disappearance of understory vegetation, and selective cutting of pine trees for fuel and construction. As a consequence, we found a shift towards early successional plant species, and a threefold increase in soil microbial activity and nutrient availability close to the settlements relative to away from them. These changes in soil fertility and vegetation contributed to 83% greater total vegetation productivity, 35 % greater plant biomass, and 23% and 16% greater concentrations of foliar N and P nearer the settlements, leading to a greater quantity and quality of litter inputs. Because decomposer activity was also 40% greater towards the settlements, soil organic matter cycling and nutrient availability were further increased, leading to likely positive feedbacks between the aboveground and belowground components resulting from historic land use. Although not all of the activities typical of Sami have left visible residual traces on the ecosystem after 100 y, their low-intensity but long-term land-use at settlement sites have triggered a rejuvenation of the ecosystem which is still present. Our data demonstrates that aboveground-belowground interactions strongly control ecosystem responses to historical human land-use, and that medium to long-term consequences of even low-intensity human activities must be better accounted for if we are to predict and manage ecosystems succession following land-use abandonment.

Description: Ecology, Volume 0, Issue 0, Ahead of Print. Existing individual size distribution (ISD) theories assume that the trophic level (TL) of an organism varies as a linear function of its log body size. This assumption predicts a power-law distribution of the ISD, i.e. a linear relationship between size and abundance in log space. However, the secondary structure of ISD (nonlinear dome shape structures deviating from a power-law distribution) is often observed. We propose a model that extends the metabolic theory to link the secondary structure of ISD to nonlinear size-TL relationship. This model is tested with empirical data collected from a subtropical reservoir. The empirical ISD and size-TL relationships were constructed by FlowCAM imaging analysis and stable isotope analyses, respectively. Our results demonstrate that the secondary structure of ISD can be predicted from the nonlinear function of size-TL relationship and vice versa. Moreover, these secondary structures arise due to (1) zooplankton omnivory and (2) the trophic interactions within microbial food webs.

Description: Herein, we report on the crystal structures of Nb 2 AlC and TiNbAlC—actual composition (Ti 0.45 ,Nb 0.55 ) 2 AlC—compounds determined from Rietveld analysis of neutron diffraction patterns in the 300–1173 K temperature range. The average linear thermal expansion coefficients of a Nb 2 AlC sample in the a and c directions are, respectively, 7.9(5) × 10 −6 and 7.7(5) × 10 −6  K −1 on one neutron diffractometer and 7.3(3) × 10 −6 and 7.0(2) × 10 −6  K −1 on a second diffractometer. The respective values for the (Ti 0.45 ,Nb 0.55 ) 2 AlC composition—only tested on one diffractometer—are 8.5(3) × 10 −6 and 7.5(5) × 10 −6  K −1 . These values are relatively low compared to other MAX phases. Like other MAX phases, however, the atomic displacement parameters (APDs) show that the Al atoms vibrate with higher amplitudes than the Ti and C atoms, and more along the basal planes than normal to them. When the predictions of the APDs obtained from density functional theory are compared to the experimental results, good quantitative agreement is found for the Al atoms. In case of the Nb and C atoms, the agreement was more qualitative.

Description: In this study, lithium disilicate (LS 2 ) glass samples with different particle sizes ranging from less than 105 to 850 μm were prepared. These specimens were inserted in a Pt-Rh DSC crucible and heated to 850°C at different rates (ϕ = 0.5–30 K/min) to identify their crystallization peaks. The activation energies for the overall crystallization ( E ) and the Avrami coefficient ( n ) were evaluated using different nonisothermal models. Specifically, n was evaluated using the Augis–Benett model and the Ozawa method, and E was evaluated using the Kissinger and Ligero methods. As expected, the coarse particles mainly crystallized in the volume, while surface crystallization was predominant in the samples with particle sizes of less than 350 μm. This result was confirmed through SEM analysis of the double stage heat-treated samples. In contrast with previous studies, our results demonstrated that the activation energy decreased as the particle size increased. In addition, no clear correlation between the peak intensity (δ T p ) and the particle size was observed.

Description: In this letter, 2-μm Pb 0.97 La 0.02 (Zr 0.75 Sn 0.18 Ti 0.07 )O 3 antiferroelectric thick film with tetragonal structure was prepared. The effects of operating electric field, temperature, and frequency on the thermal–electrical energy harvesting capacity of the film were studied by using the Olsen cycle. The results demonstrated that giant energy harvesting effect could be realized in the antiferroelectric thick film. The maximum harvestable energy density per cycle of the film was about 7.8 J/cm 3 at 1 kHz, which was the largest reported value to date. The corresponding energy harvesting efficiency was 0.53%. Moreover, the film had a low leakage current density (about 7.3 × 10 −7 and 3.9 × 10 −5  A/cm 2 at 25 and 200°C, respectively), which was favorable for its application in the devices of the thermal–electrical energy harvesting.