Deposition Of Pellets Research Articles

Metatranscriptomic holobiont analysis of carbohydrate-active enzymes in the millipede Telodeinopus aoutii (Diplopoda, Spirostreptida)

As important decomposers of soil organic matter, millipedes contribute to lignocellulose decomposition and nutrient cycling. The degradation of lignocellulose requires the action of several carbohydrate-active enzymes (CAZymes) and, in most invertebrates, depends on the activity of mutualistic gut microorganisms. To address the question of the importance of the microbiota and endogenous (host) enzymes in digestive processes in millipedes, we analyzed metatranscriptomic data from the tropical millipedeTelodeinopus aoutiiat the holobiont level. Functional annotation included identification of expressed CAZymes (CAZy families and EC terms) in the host and its intestinal microbiota, foregut, midgut, and hindgut, compared to non-intestinal tissues. Most of the 175 CAZy families were expressed exclusively in the gut microbiota and more than 50% of these microbial families were expressed exclusively in the hindgut. The greatest diversity of expressed endogenous CAZymes from all gut sections was found in the midgut (77 families). Bacteria were the major microbial producers of CAZymes, Proteobacteria dominating in the midgut and Bacteriodetes with Firmicutes in the hindgut. The contribution of the eukaryotic microbiota to CAZymes production was negligible. Functional classification of expressed CAZy families confirmed a broad functional spectrum of CAZymes potentially expressed in the holobiont. Degradation of lignocellulose in the digestive tract of the millipedeT. aoutiidepends largely on bacterial enzymes expressed in the hindgut. Endogenous cellulases were not detected, except for the potentially cellulolytic family AA15, but an expression of cellulolytic enzymes of this family was not confirmed at the EC-number level. The midgut had the greatest diversity of expressed endogenous CAZymes, mainly amylases, indicating the importance of digesting α-glucosidases for the millipede. In contrast, bacterial lignocellulolytic enzymes are sparsely expressed here. The hindgut was the hotspot of microbial degradation of cellulose and hemicellulases. The gain of the millipede from the microbial lignocellulose degradation in the gut, and consequently the mutualistic status of the relationship between the millipede and its cellulolytic gut bacteria, depends on the ability of the millipede to take up microbial metabolites as nutrients through the hindgut wall. Enzymes expressed in the intestine can degrade all components of lignocellulose except lignin. Assuming that soil microbiota is partially degraded lignin in the millipede diet,T. aoutiican be considered a decomposer of soil organic matter relying primarily on its gut bacteria. The deposition of millipede fecal pellets containing an organic matter modified by the hindgut bacterial community could be of ecological significance.

Sedimentological and Geochemical Analysis of the Eocene Tallahatta Formation in Northern Mississippi, USA

The Eocene Tallahatta Formation forms part of the Tallahatta-Winona aquifer, which is part of the lower Claiborne confining unit of the Mississippi Embayment. A thorough understanding of the distribution of natural resources within the Tallahatta is limited by a lack of detailed studies at the outcrop and pore scales. In this study, we integrate particle size, petrographic, lithofacies, and geochemical analyses to interpret depositional environments, sequence stratigraphy, provenance, and diagenetic history from outcrops in Grenada County, Mississippi. Lithofacies include unprotected sand flat, tidal channel, open tidal mudflat, protected tidal flat, lower and middle shoreface, offshore transition, and offshore shelf settings. Lithofacies associations indicate that the Tallahatta consists of at least two parasequences within a falling stage systems tract (FSST). This is the first report on FSST strata from the Tallahatta Formation. Petrographic and geochemical results show that sediments were sourced from Precambrian Laurentian basement, recycled Appalachian basin sediment, and the Appalachian hinterland. Upsection changes in geochemistry represent an increase in contributions from recycled Appalachian basin sediment and progressive weathering of Acadian orogeny elements. Geochemistry also suggests that potentially economically important Ti-rich minerals are concentrated in tidal flat facies and scarce in shoreface facies. Primary porosity and bioturbation exert the greatest influence on the high porosity within many lithofacies. Early diagenesis also included detrital clay coating of framework grains, deposition of fecal pellets, minor chemical weathering, and hematite precipitation. Fecal pellets were altered to glauconite and opal cement was precipitated shortly after deposition or during early burial. Shrinkage of fecal pellets during glauconitization introduced minor moldic porosity. Limited burial produced minor physical compaction and only slightly reduced porosity. Abundant hematite precipitation during exhumation greatly decreased porosity locally.

Influence of Bioturbation on Hyporheic Exchange in Streams: Conceptual Model and Insights From Laboratory Experiments

AbstractBioturbation occurs in streambeds by the action of a range of faunal species, but little is known about how it could modify the hyporheic exchange in streams. Previous experimental work investigating the effects of sediment‐biota interaction on exchange across the sediment‐water interface has been largely conducted in small mesocosms or infiltration columns that do not represent the lotic environment adequately. Therefore, the experimental findings from these studies may not be transferable to flowing water environments (e.g., streams). In this work, we first present a conceptual model demonstrating the causal pathways through which the sediment reworking and burrow ventilation processes (together referred to as bioturbation) could potentially modify the hyporheic flow regime. Next, to study the role of activities of faunal organisms in lotic environments and test some of the arguments presented in the model, laboratory experiments are conducted in re‐circulating flumes. The experiments involved investigating the modification of dune‐induced hyporheic flow due to the activities of a model bioturbating organism, Lumbriculus variegatus, following a control (without organisms) and treatment (with organisms) based experimental design. The sediment reworking activities such as surficial deposition of fecal pellets and burrowing by L. variegatus caused significantly higher hyporheic flux, longer mean residence times, and deeper solute penetration in the treatment flumes relative to the control flumes. We advocate that more intensive laboratory experiments and field investigations must be conducted to test the propositions put forward in the conceptual model and advance our understanding of the role of bioturbation process in fluvial ecosystems.

Pressure‐Induced Perovskite‐to‐non‐Perovskite Phase Transition in CsPbBr3

AbstractThe expanding range of optoelectronic applications of lead‐halide perovskites requires their production in diverse forms (single crystals, thin‐ and thick‐films or even nanocrystals), motivating the development of diverse materials processing and deposition routes that are specifically suited for these structurally soft, low‐melting semiconductors. Pressure‐assisted deposition of compact pellets or thick‐films are gaining popularity, necessitating studies on the pressure effects on the atomic structure and properties of the resulting material. Herein we report the phase transformation in bulk polycrystalline cesium lead bromide from its three‐dimensional perovskite phase (γ‐CsPbBr3) into the one‐dimensional polymorph (δ‐CsPbBr3) upon application of hydrostatic pressure (0.35 GPa). δ‐CsPbBr3 is characterized by a wide bandgap of 2.9 eV and broadband yellow luminescence at 585 nm (2.1 eV) originating from self‐trapped excitons. The formation of δ‐CsPbBr3 was confirmed and characterized by Raman spectroscopy, 207Pb and 133Cs solid‐state nuclear magnetic resonance, X‐ray diffraction, absorption spectroscopy, and temperature‐dependent and time‐resolved photoluminescence spectroscopy. No such phase transition was observed in colloidal CsPbBr3 nanocrystals.

A large‐scale double‐stage‐screw 3D printer for fused deposition of plastic pellets

ABSTRACTFused deposition molding (FDM) is the most popular technology in the fields of three‐dimensional printing, but it is hard to use a variety of plastic materials due to the limitation of filament form of material. Using plastic pellets as printing materials gives advantages in cost, processing speed, and available materials. In this work, a large‐scale double‐screw FDM three‐dimensional printer based on plastic pellets has been designed. It is capable of printing large plastic products at a low cost and high speed. Using ABS + 10%GF as printing material, this work is first focused on the effects of the pressure and speed of the metering screw on the flowrate of melt. The equation for the relationship of these three parameters was established as well. Based on this equation, the effects of melt flow, printing speed, and layer thickness on the width of fused filament were investigated with experiments. Furthermore, the effects of printing spacing between fused filaments on surface accuracy and bonding strength were also explored. By printing models, it was revealed that the designed printer is able to print products with plastic pellets. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45147.

Modeling the benthic loading of particulate wastes from a gilthead seabream (Sparus aurata) farm during a complete rearing cycle

The relationship between aquaculture activities and water quality plays an important role in determining the volume and quality of production as well as the impact of aquaculture on the aquatic environment. The natural assimilation capacity of a waterbody is often insufficient to cope with the continuous input of wastes from fish farms. Their impact depends not only on the waste itself, but also on other factors such as the local hydrodynamics at the farm site or the cultured species’ feeding pattern. We combine a hydrodynamic model with a transport code to simulate the deposition of fecal pellets and uneaten feed from a gilthead seabream farm in the western Mediterranean Sea. The simulation spans a full 17-month rearing cycle and considers the natural variations in the feed demand of the fish during this period. The results indicated that the maximum benthic concentrations of organic matter and nutrients were found within a 100–500 m distance from the cages, depending on the type of particulate waste and on the local current characteristics. The combination of a long simulation period and realistic hydrodynamic patterns highlights the importance of considering long-term current variability when assessing the environmental impact of fish farms, and stresses the limitations of current simplistic assessment practices.

Co-pelletization of sewage sludge and biomass: Thermogravimetric analysis and ash deposits

In this study, the combustion behaviors of sludge–biomass mixed pellets with different sludge ratios in air atmosphere were investigated by thermogravimetric analysis. The pellets consisted of sludge and Chinese fir or rice straw with sludge ratios of 0%, 25%, 50%, 75% and 100%, respectively. The thermogravimetric data were applied for kinetic analysis using the Coats and Redfern (CR) equation. Results showed that there were four main stages such as dehydration, volatile oxidation, char burning and burnout during thermal decomposition of pellets. The reactivities of sludge–biomass pellets were improved by the increment of the mixing ratio of biomass. In addition, the potential slagging behaviors of the resultant ashes were evaluated by X-ray fluorescence (XRF). The suitable sludge to biomass ratio should consider the combustion properties and ash slagging deposition of pellets. It is inappropriate for the production of sludge–straw pellet in the present state due to the high ash slagging potential.

Large salp bloom export from the upper ocean and benthic community response in the abyssal northeast Pacific: Day to week resolution

A large bloom of Salpa spp. in the northeastern Pacific during the spring of 2012 resulted in a major deposition of tunics and fecal pellets on the seafloor at ∼ 4000 m depth (Sta. M) over a period of 6 months. Continuous monitoring of this food pulse was recorded using autonomous instruments: sequencing sediment traps, a time‐lapse camera on the seafloor, and a bottom‐transiting vehicle measuring sediment community oxygen consumption (SCOC). These deep‐sea measurements were complemented by sampling of salps in the epipelagic zone by California Cooperative Ocean Fisheries Investigations. The particulate organic carbon (POC) flux increased sharply beginning in early March, reaching a peak of 38 mg C m−2 d−1 in mid‐April at 3400 m depth. Salp detritus started appearing in images of the seafloor taken in March and covered a daily maximum of 98% of the seafloor from late June to early July. Concurrently, the SCOC rose with increased salp deposition, reaching a high of 31 mg C m−2 d−1 in late June. A dominant megafauna species, Peniagone sp. A, increased 7‐fold in density beginning 7 weeks after the peak in salp deposition. Estimated food supply from salp detritus was 97–327% of the SCOC demand integrated over the 6‐month period starting in March 2012. Such large episodic pulses of food sustain abyssal communities over extended periods of time.

The nature and origin of deep ocean clay crust from the Gulf of Guinea

Deep ocean sediments off the west coast of Africa exhibit a peculiar undrained strength profile in the form of a crust, albeit of exceptionally high water content, overlying normally consolidated clay. Hot-oil pipelines are installed into these crustal sediments, so their origins and characteristics are of great interest to pipeline designers. This paper provides evidence for the presence of burrowing invertebrates in crust material, and for the way sediment properties are modified through their creation of burrows, and through the deposition of faecal pellets. A variety of imaging techniques are used to make these connections, including photography, scanning electron microscopy and X-ray computer tomography. However, the essential investigative technology is simply the wet-sieving of natural cores, which reveals that up to 60% by dry mass of the crustal material can consist of smooth, highly regular, sand-sized capsules that have been identified as the faecal pellets of invertebrates such as polychaetes. Mechanical tests reveal that these pellets are quite robust under effective stresses of the order of 10 kPa, acting like sand grains within a matrix of fines. Their abundance correlates closely with the measured strength of the crust. While this can easily be accepted in the context of a pellet fraction as high as 60%, the question arises how a smaller proportion of pellets, such as 20%, is apparently able to enhance significantly the strength of a sediment that otherwise appears to be normally consolidated. A hypothesis is suggested based on the composition of the matrix of fines around the pellets. These appear to consist of agglomerates of clay platelets, which may be the result of the breakdown of pellets by other organisms. Their continued degradation at depths in excess of 1 m is taken to explain the progressive loss of crustal strength thereafter.

Macropod habitat use and response to management interventions in an agricultural - forest mosaic in north-eastern Tasmania as inferred by scat surveys

Context Native pest herbivores often require population numbers to be controlled in landscape settings where agricultural, plantation forests and native forests are juxtaposed. The Tasmanian pademelon Thylogale billardierii and the red-necked wallaby Macropus rufogriseus rufogriseus are among the most abundant native pest herbivore species in Tasmania. Aims We aimed to determine the habitat use of pademelons and wallabies in response to (i) environmental and seasonal variation, and (ii) two different wildlife management interventions (shooting and fencing) in an agricultural–forest mosaic in north-eastern Tasmania. Methods Macropod abundance before and after shooting and fencing management interventions were estimated by changes in the rate of deposition of faecal pellets (scats per unit area per time interval) on an array of permanent transects that were stratified across three habitat types (agricultural land, plantation forest, and native forest). An experiment was also conducted to determine the endurance of fresh scats in the three habitats. Key results More than 90% of scats remained undecomposed for over five months, and more than 50% of scats remained undecomposed for over 11 months across the study site. Decomposition rates were significantly influenced by habitat type, specifically, highest in agricultural land and lowest in native forest for both species. Scat deposition rates showed that species abundance was influenced by habitat type and season. Macropod abundance was highest in agricultural land and lowest in native forest. Compared with summer and early autumn, pademelon scat abundance significantly decreased in late autumn and spring on agricultural land but showed no change for plantation forest or native forest. Wallaby scats showed similar seasonal trends for all three habitats, lower in late autumn and spring compared with summer and early autumn. Following each of the management interventions, macropod scat deposition rates decreased predominantly on agricultural land. This effect decreased with increasing distance from intervention loci. Conclusions We demonstrate that scat monitoring provides a useful survey technique for the assessment of macropod habitat use, and show that macropods select for agricultural habitats. Shooting and fencing interventions reduced the use of agricultural habitats, but this effect was localised. Implications A whole-landscape perspective is required when assessing the impacts of management interventions on pest populations. Results highlight the formidable challenges in controlling native herbivores in habitat mosaics, given the localised effects of management interventions and the importance of environmental and seasonal factors as drivers of habitat use.

Are the faecal pellets of kangaroos(Macropusspp.) a source of nutrients and carbon in an inland floodplain wetland during flooding? A preliminary experimental inundation study in the Macquarie Marshes, New South Wales

Kangaroos (Macropus spp.) are one of the most abundant native macrofauna on Australian floodplains with a positive relationship between their density and the deposition of faecal pellets that contain nutrients and carbon.We tested whether kangaroo faecal pellets are a source of nutrients and carbon during flooding in the Macquarie Marshes, an inland floodplain wetland, in south-eastern Australia. The faecal pellets of kangaroos, most likely of Red Kangaroo (M. rufus), were found on the dry floodplain adjacent to Bora Channel (~30.6433°S/~ 147.5351 °E) at a density of 142±54 m-2 (mean±SE, n=3). Following artificial inundation, we monitored the release of total nitrogen (TN), total phosphorus (TP) and dissolved organic carbon (DOC) five times over a six-day period from mesocosms deployed in situ.Three mesocosms contained faecal pellets and three mesocosms contained marsh floodplain sediments (top 5 cm of sediment consisting of soils and plant material) with faecal pellets removed. The concentrations (mean±S...

Small-scale variation within a Modiolus modiolus (Mollusca: Bivalvia) reef in the Irish Sea. III. Crevice, sediment infauna and epifauna from targeted cores

Beds of Modiolus modiolus, in areas of moderate to strong tidal currents, develop into reefs with a relief of wave like undulations 0.09–0.45 m in amplitude and length scales of 6–18 m. Cores taken by diver operated suction sampler were targeted at positions on the ridges and troughs of a reef, in the Irish Sea off north-west Wales, allowing the fauna to be compared between adjoining ridges and troughs. Sessile epifauna was mostly attached to the larger mussels clumped together on the ridges. The crevice fauna and infauna were also nearly three times more abundant on the ridges, but the lists of species were similar from the two sub-habitats. Species richness was higher on the ridges, however, diversity and evenness measures were similar for ridges and trough samples. The Modiolus sub-habitats were found to be distinct from other macrofaunal assemblages in the wider southern Irish Sea. Deposition of faecal pellets in the spatially complex habitat amongst the mussels provided conditions suitable for an infauna more typical of inshore muddy sands enriched by organic matter. The scale of the ridge and trough morphology may increase variability between replicates when grabs are used remotely to sample this type of biogenic feature.

Wetland soil and vegetation bismuth content following experimental deposition of bismuth pellets

Bismuth pellets have been approved as a non-toxic alternative to lead pellets in Canada since 1997 but, to our knowledge, there is little literature for soil and vegetation bismuth content in areas of bismuth pellet deposition. The present study addresses this shortcoming by measuring wetland soil and vegetation bismuth content following experimental deposition of bismuth pellets under ambient and experimentally increased acidic deposition conditions. We manipulated 24 plots in a fully factorial design (bismuth shot x soil acidification) in a south-eastern Ontario freshwater wetland during 1999-2003. Soil pH (range 6.5-7.3) increased significantly (p = 0.001) during the experimental period but there were no significant differences amongst treatments (p = 0.79). Significantly (p < 0.05) greater bismuth concentrations were measured in soil receiving bismuth pellets (mean +/- SE, n = 6; with acidification = 2.55 +/- 1.02 microg Bi g(-1) dry mass [DM]; without acidification = 6.40 +/- 2.23 microg Bi g(-1) DM) compared to plots that were not seeded with bismuth pellets (without acidification = 0.42 +/- 0.09 microg Bi g(-1) DM; with acidification = 0.39 +/- 0.10 microg Bi g(-1) DM). Nevertheless, bismuth levels in 20 of 24 aboveground tissue samples from the Carex lacustris-Agrostis scabra community were below detection levels (0.057 microg Bi g(-1) DM); the other samples ranged from 0.065 to 0.095 microg Bi g(-1) DM, similar to global background levels. Primary productivity in plots receiving bismuth pellets and soil acidification was not significantly (p = 0.15) different to vegetation in plots that were not manipulated. The results suggest bismuth mobilization from bismuth pellets into soil but not to aboveground vegetation.

Characteristics of Post-Disruption Runaway Electrons with Impurity Pellet Injection

Characteristics of post-disruption runaway electrons with impurity pellet injection were investigated for the first time using the JT-60U tokamak device. A clear deposition of impurity neon ice pellets was observed in a post-disruption runaway plasma. The pellet ablation was attributed to the energy deposition of relativistic runaway electrons in the pellet. A high normalized electron density was stably obtained with nebar/nGW ˜ 2.2. Effects of prompt exhaust of runaway electrons and reduction of runaway plasma current without large amplitude MHD activities were found. One possible explanation for the basic behavior of runaway plasma current is that it follows the balance of avalanche generation of runaway electrons and slowing down predicted by the Andersson-Helander model, including the combined effect of collisional pitch angle scattering and synchrotron radiation. Our results suggested that the impurity pellet injection reduced the energy of runaway electrons in a stepwise manner.

Deposition of Fuel Pellets Injected into Tokamak Plasmas

Pellet injection has been used on tokamak devices in a number of experiments to provide plasma fueling and density profile control. The mass deposition of these fuel pellets, defined as the change in density profile caused by the pellet, has been found to show an outward displacement of the ablated material from that expected by mapping the theoretical ablation rate onto the flux surfaces. This suggests that fast transport of the pellet ablatant occurs during the flow along field lines that may be driven by VB effects. A comparison of the deposition of pellets from different machines shows similar behavior. Initial results from alternative injection locations designed to take advantage of the outward ablatant drift is presented.

The spatial and temporal distribution of koala faecal pellets

Faecal pellets were collected under trees used by free-ranging koalas in south-western, central and south-eastern Queensland to determine the spatial and temporal distribution of pellets with respect to the activity of koalas. Deposition of faecal pellets by koalas was analysed according to the time of day at which the tree was occupied. For free-ranging koalas, 47% of daily faecal pellet output was recovered using a collection mat of 8 × 8 m placed under a day-roost tree. The best predictor of pellet production was the presence of a koala in a tree between 1800 hours and midnight. For other periods, there was no relationship between period of tree occupancy and faecal pellet recovery. There was a significant relationship between the average length of tree occupancy and the time of day that a koala entered a tree.

Comparison of Leporid Bones in Raptor Pellets, Raptor Nests, and Archaeological Sites in the Great Basin

Leporid (cottontail and hare) bones deposited on the landscape in raptor pellets may exhibit more forelimb than hindlimb bones, few complete bones, more subadult than adult bones, and abundant vertebrae. In contrast, raptor nest assemblages may exhibit more tibiae than forelimb bones, few incomplete bones, more adult than subadult bones, and few vertebrae. Approximately 1 to 2 percent of leporid bones deposited in either raptor nests or raptor pellets are likely to exhibit puncture marks. Leporid bone assemblages created by humans in the Great Basin may exhibit large numbers of adult Lepus or adult Sylvilagus tibia diaphysis cylinders, many burned and unidentifiable fragments of bone, few identifiable vertebrae and sacra, and assemblages that consist primarily of adult animals. These data suggest that archaeologists should be able to identify leporid bone assemblages that were created largely or solely by the deposition of raptor pellets, by the deposition of unswallowed bones under raptor nests, or by the deposition of bones by humans. Assemblages created by any combination of these three processes, however, will be more difficult to interpret.

The influence of the filter-feeding bivalve Cerastoderma edule L. on microphytobenthos: a laboratory study

The effect of the filter-feeding bivalve Cerastoderma edule L. on microphytobenthos was investigated in three laboratory experiments. In the first experiment adult specimens of C. edule placed in flow-through aquaria containing sieved sediment were compared to aquaria without C. edule. The aquaria were incubated for 40 days, and sampled weekly for inorganic nutrient concentrations in the overlying water, sediment pigment concentrations and determination of benthic primary production. The presence of C. edule significantly increased the release of NH 4 + and PO 4 3− to the overlying water. The chlorophyll α concentration in C. edule treatments increased, and was significantly higher than in controls. The benthic primary production in C. edule treatments increased, reaching a mean maximum of 27.9 mg C·M −2·h −1, while the controls stayed at the initial mean level of 14.7 mg C·m −2·h −1 throughout the experiment. When the possible effect of fertilizing with faecal pellets from C. edule was tested in a second experiment, no differences were observed in nutrient fluxes, chlorophyll α concentration or primary production. In a third experiment, the effect of nutrients released by C. edule was investigated. Water from an aquarium containing a number of C. edule equivalent to the high natural density of cockles at the site of collection of the sediment was directed to four of the aquaria. The primary production was significantly higher in C. edule treatments than in controls. Thus the stimulating effect of C. edule on the microphytobenthos seems to be mediated by the release of nutrients, mainly NH 4 +, by the cockles themselves rather than through the deposition of faecal pellets.

Patch disturbances in arid grassy dunes: antelope, rodents and annual plants

In arid grassland, patches with reduced perennial plant cover support a diverse annual flora that is also present at a lower density in the surrounding vegetation. The patches appear to be maintained in these arid dunefields by the activities of antelope and burrowing rodents, which destroy perennial grasses by trampling or digging, thereby creating spaces for annual plants to germinate and grow, and increasing the nutrient status of the soil through the deposition of faecal pellets. Although seed was brought in to such patches by antelope, the amount was small and mainly of a species that grows only on saline pans. No intact seed was found in a small sample of rodent faecal pellets.

Pulsed laser deposition of thin superconducting films of Ho1Ba2Cu3O7 − x and Y1Ba2Cu3O7 − x

Thin films of Ho1Ba2Cu3O7 − x and Y1Ba2Cu3O7 − x were deposited on SrTiO3 and Al2O3, substrates by pulsed laser deposition of high-Tc bulk superconductor pellets in vacuum. Following annealing in O2 at 800–900 °C the films were superconducting with typical Tc (50%) = 89 K and transition widths of 10 K. Rutherford backscattering spectrometry (RBS) and secondary ion mass spectrometry (SIMS) were utilized to study the stoichiometry of the as-deposited films for laser energy, densities between 0.11 and 4.5 J cm−2. The films were deficient in holmium and yttrium for energy densities below 0.6 and 0.4 J cm −2, respectively. The films were stoichiometric for fluences above 0.6 J cm−2. In addition, preliminary time dependence and spectroscopic observations of the laser-produced plasma are presented. The results indicate an ablation mechanism that at high energy densities preserves stoichiometry. TEM and x-ray characterization of annealed, superconducting Ho1Ba2Cu3O7 − x films on (100) SrTiO3 showed mixed regions of epitaxially oriented 1:2:3 material with either the c axis or a axis oriented along the surface normal. The a-axis-oriented material grew preferentially in the films with b, c, twinning.