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Pits
Kinds of Pits Terms modified by Pits Selected AbstractsDetection efficiency of multiplexed Passive Integrated Transponder antennas is influenced by environmental conditions and fish swimming behaviourECOLOGY OF FRESHWATER FISH, Issue 4 2009J. C. Aymes Abstract,,, The efficiency of a Passive Integrated Transponder (PIT)-tag detection system was tested during a 23-day experiment using a permanent digital video to record the passage of fish through multiplexed antennas. Coupling video to the PIT system allowed the detection of error sources and the correction of erroneous data. The efficiency of the detection system and its variation were investigated according to fish swimming speed, direction of movement and individual fish behaviour. Influence of time and environmental conditions on detection results were also checked. The PIT tag system was 96.7% efficient in detecting fish. Upstream movements were better detected (99.8%) than downstream movements (93.7%). Moreover, results showed that efficiency rate was not stable over the experiment; it was reduced on stormy days. Several sources of errors were identified such as sub-optimal orientation of the PIT tag relative to the antenna plane, the influence of fish swimming speed, individual fish behaviour and influence of environmental conditions. [source] Tagging effects on three non-native fish species in England (Lepomis gibbosus, Pseudorasbora parva, Sander lucioperca) and of native Salmo truttaECOLOGY OF FRESHWATER FISH, Issue 2 2009S. Stak Abstract,,, To address the dearth of information on tagging effects and long-term survivorship of tagged fish in native and introduced species, laboratory and field investigations were undertaken on three non-native fish species (pumpkinseed Lepomis gibbosus; topmouth gudgeon Pseudorasbora parva; pikeperch Sander lucioperca) tagged with coded-wire (CW), passive integrated transponder (PIT), radio (RT) telemetry and/or acoustic tags (AT), with survivorship of native brown trout (Salmo trutta) examined in the field. Laboratory results revealed high survivorship following tag attachment/insertion and resumption of feeding within 24,48 h of tagging (all mortalities could be attributed to an unrelated outbreak of fungal infection), with retention rates being high in both pumpkinseed and pikeperch but low in topmouth gudgeon (excluded from field studies). In the field, short-term post-operation survival was high in pikeperch, pumpkinseed and brown trout. In pumpkinseed and trout, 100% of RT fish survived a 24,30 day tracking study, with 60% and 80%, respectively, recaptured alive at least 3 months post-tagging. Of PIT tagged pumpkinseed, 44% were recaptured (after 6,18 months), with small-sized, CW-tagged fish (0.38 g weight) captured up to 1 year after tagging. In pikeperch, all AT fish except one (the smallest specimen) survived their full expected tracking period (i.e. tag life) , the single lost specimen survived at least half of its expected tracking period (i.e. 6 month battery life). Overall, the tagging methods used were highly effective in pumpkinseed and pikeperch, showing good retention and survival, but PIT tagging of topmouth gudgeon was plagued by low survivorship and tag rejection. [source] Evaluation of passive integrated transponder tags for marking the bullhead (Cottus gobio), a small benthic freshwater fish: effects on survival, growth and swimming capacityECOLOGY OF FRESHWATER FISH, Issue 3 2007G. Knaepkens Abstract,,, This study examined potential adverse effects of surgically implanted passive integrated transponder (PIT) tags (12 × 2.1 mm) on bullhead (Cottus gobio L.) of three different length-classes (I: 50,64 mm, II: 65,79 mm, III: 80,94 mm). During a 7-week laboratory experiment, the rate of PIT tag loss, incision closure time, survival, growth and swimming capacity were tested. The PIT tag weight to fish body weight ratio varied between 1.04% and 4.85%. The mean incision closure time differed significantly among length-classes and varied between 2.8 (I) and 4.3 (III) weeks. Nevertheless, PIT tag retention did not differ among length-classes and was ,90%. The survival of untagged, sham-tagged and PIT-tagged bullheads was ,90% and did not differ within or among length-classes. Finally, within each length-class, there was no difference in growth and swimming capacity among treatments. Hence, these results suggest the applicability of PIT tags for individually tagging bullheads ,50 mm. [source] Efficiency of a nature-like bypass channel for sea trout (Salmo trutta) ascending a small Danish stream studied by PIT telemetryECOLOGY OF FRESHWATER FISH, Issue 3 2003K. Aarestrup Abstract , Upstream passage of adult sea trout (Salmo trutta) in a nature-like bypass channel was investigated in the Tirsbæk brook, Denmark, in autumn and winter 1999/2000. Sea trout were caught by electrofishing up- and downstream of the weir at which the bypass was situated. Fish were tagged with passive integrated transponder (PIT) tags and released downstream of the weir. Automatic PIT-tag logging stations were positioned downstream, in the lower part, and at the upstream exit of the bypass to investigate the passage success of the fish. The bypass was neither size- nor sex-selective in the size ranges investigated. The majority (68%) of fish approached the bypass at night. Over 90% of tagged upstream-searching fish located and entered the bypass channel, but only about half of them passed through. The inefficiency is suggested to be because of a combination of the length of the bypass channel and inadequate flow in the bypass channel. [source] REFORM OF THE PERSONAL INCOME TAX SYSTEM IN AUSTRALIAECONOMIC PAPERS: A JOURNAL OF APPLIED ECONOMICS AND POLICY, Issue 4 2005Jeff Pope This paper examines the case for reform of Australia's Personal Income Tax (PIT), argues that it is outdated, and demonstrates a growing consensus for reform. The importance of tax avoidance, particularly the use of trusts, in the Australian PIT system, and arguably its abrogation of modern-day criteria of what constitutes a ,good tax', is emphasised. Three possible ,reform' options are identified: the ,tinkering and tokenism' approach of current Government policy; moderate reform and a proposed ,significant reform option' costing around $22 billion. Essentially this comprises company and top PIT rate equalisation and a doubling of the tax-free threshold. But funding this is problematical. Two key arguments of the paper are that: (real) simplification i.e. lower compliance costs, is an important yet usually down-played objective in reform proposals; savings from reform denying PIT deductions such as work expenses are insufficient to achieve significant PIT reform. An increase in the rate of the Goods and Services Tax (GST) from 10% to 15% (with a compensation package) is therefore advocated in a revenue-neutral analysis ignoring current Government budget surpluses. The overall outcome would be a simplified, more equitable and incentive-driven PIT system that would move Australia closer to the PIT and GST policies of other OECD countries. But the political difficulties of reform mean that the Government's ,tinkering' approach is likely to continue. [source] The Russian ,flat tax' reformECONOMIC POLICY, Issue 43 2005Anna Ivanova SUMMARY Russian's ,flat tax' In 2001, Russia dramatically reduced its higher rates of personal income tax (PIT), establishing a single marginal rate at the low level of 13%. In the following year, real revenue from the PIT increased by about 26%. This ,flat tax' experience has attracted much attention (and emulation), making it perhaps the most important tax reform of recent years. But it has been little studied. This paper asks whether the strong performance of PIT revenue was itself a consequence of this reform, using both macro evidence and, in particular, micro level data on the experiences of individuals and households affected by the reform to varying degrees. It concludes that there is no evidence of a strong supply side effect of the reform. Compliance, however, does appear to have improved quite substantially , by about one third, according to our estimates , though it remains unclear whether this was due to the parametric tax reform or to accompanying changes in enforcement. , Anna Ivanova, Michael Keen and Alexander Klemm [source] Clinical features of seizures associated with parahippocampal/inferior temporal lesions compared to those with hippocampal sclerosisEPILEPSIA, Issue 9 2010Laura Mirandola Summary Temporal lobe epilepsy (TLE) is not a unitary electroclinical imaging syndrome. We asked if seizures arising from the parahippocampal-inferior temporal (PIT) region differ from those associated with hippocampal sclerosis (HS). The electroclinical features of 22 patients with HS and 14 patients with lesions in the PIT region who underwent epilepsy surgery and were seizure free for at least 2 years postoperatively were analyzed retrospectively. Patients with PIT lesions had a higher frequency of hypermotor and bilateral features and a lower frequency of behavioral arrest at the onset of seizure compared to cases with HS, suggesting that TLE originating in the PIT area can mimic frontal lobe epilepsy or contralateral mesial TLE. [source] The onset of downstream movement of juvenile Atlantic salmon, Salmo salar L., in a chalk streamFISHERIES MANAGEMENT & ECOLOGY, Issue 2 2002W. D. RILEY The downstream movements of wild Atlantic salmon, Salmo salar L., from their established feeding territories in the River Itchen, Hampshire, UK, were logged continuously over an 11-month period using a passive integrated transponder (PIT) antenna system. The time of these movements was then related to a number of monitored and calculated environmental parameters. Initial downstream movement of smolts in April was correlated with the onset of darkness, at which time salmon moved from their established feeding territories alone. No relationship was found between the number of smolts migrating and river flow or maximum daily water temperature. The timing of downstream movement of parr between October and March was random with regard to sunset and time of maximum daily water temperature, suggesting the environmental cue that initiates movement may be different outside the spring smolt period. [source] FT-IR measurements of petroleum fluid inclusions: methane, n -alkanes and carbon dioxide quantitative analysisGEOFLUIDS (ELECTRONIC), Issue 1 2001J. Pironon Abstract A recent advancement in petroleum geochemistry is to model fossil oil composition using microthermometric and volumetric data acquired from individual fluid inclusion analysis. Fourier transform infrared (FT-IR) microspectroscopy can record compositional information related to gas (CH4 and CO2) and alkane contents of petroleum inclusions. In this study, a quantitative procedure for FT-IR microspectrometry has been developed to obtain, from individual fluid inclusions, mol percentage concentrations of methane, alkanes and carbon dioxide as constraints to thermodynamic modelling. A petroleum inclusion in a sample from the Québec City Promontory nappe area was used as standard to record a reference spectrum of methane. The analytical procedure is based on the measurement of CH4/alkane and CH4/CO2 band area ratios. CH4/alkane infrared band area ratio is obtained after spectral subtraction of the reference methane spectrum. This area ratio, affected by absolute absorption intensities of methane, methyl and methylene, provides a molar CH4/alkane ratio. Methyl/methylene ratio (CH2/CH3) ratio is obtained following procedures established in previous work. CO2/CH4 concentration ratio is estimated from relative absolute absorption intensities. Application to natural inclusions from different environments shows good correlation between FT-IR quantification and PIT (petroleum inclusion thermodynamic) modelling. [source] Evaluation of VIE and PIT tagging methods for juvenile cyprinid fishesJOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2009J. D. Bolland Summary Retention and mortality associated with visible implant elastomer (VIE) and passive integrated transponder (PIT) tagged juvenile chub [Leuciscus cephalus (L.)], dace [Leuciscus leuciscus (L.)] and roach [Rutilus rutilus (L.)] were evaluated. PIT tag retention (96.6,100%) was higher than VIE over the 6-month duration of the experiment. VIE retention was significantly better in the head (96.3,98.8%) than in the fins (78.8,90.9%) the first month after tagging, but the opposite was found after 6 months (head = 21.5,57.5%; fins = 77.2,88.8%). Survival was not significantly different from controls for any treatment, except dace tagged with 23-mm PIT (significantly influenced by mass of fish at tagging) and sham PIT tagged dace, because of initial losses. PIT tags are recommended as the most suitable method for tagging individual juvenile chub, dace and roach based on high retention and survival. VIE implantation in the head (studies < 30 days) and fins (studies > 30 days) could provide a cheap, batch-marking alternative, provided retention rates are monitored. [source] Testing assumptions of mark,recapture theory in the coral reef fish Lutjanus apodusJOURNAL OF FISH BIOLOGY, Issue 3 2008C. L. Wormald This study tested assumptions of the Cormack,Jolly,Seber capture,mark,recapture (CMR) model in a population of the tropical snapper Lutjanus apodus in the central Bahamas using a combination of laboratory and field studies. The suitability of three different tag types [passive integrated transponder (PIT) tag, T-anchor tag and fluorescent dye jet-injected into the fins] was assessed. PIT tags were retained well, whereas T-anchor tags and jet-injected dye were not. PIT tags had no detectable effect on the rates of growth or survival of individuals. The capture method (fish trapping) was found to provide a representative sample of the population; however, a positive trap response was identified and therefore the assumption of equal capture probability was violated. This study illustrates an approach that can be used to test some of the critical assumptions of the CMR theory and it demonstrates that CMR methods can provide unbiased estimates of growth and mortality of L. apodus provided that trap response is explicitly modelled when estimating survival probability. [source] Analysis of the incidence of infectious pancreatic necrosis mortality in pedigreed Atlantic salmon, Salmo salar L., populationsJOURNAL OF FISH DISEASES, Issue 11 2006D R Guy Abstract A total of 77 124 Atlantic salmon post-smolts, representing 197 full-sib families produced by 149 males and 197 females, experienced a field challenge from infectious pancreatic necrosis virus (IPNV), following transfer to three separate seawater sites. The first IPN mortality was observed 45 days after transfer, and the duration of the epidemic varied between 37 and 92 days among sites. Mortalities were traced to their parental families by PIT (Passive Integrated Transpondes) tag records and DNA genotyping. Full-sib family mean incidence of mortality was calculated for each family on each site. Heritabilities were estimated based on the heterogeneity of chi-square using incidence within half-sib families and the variance in incidence among full-sib families, both on the observed and underlying liability scale. The observed correlation among families across sites was used to estimate genetic correlations. The overall mortality rate was 10.8%, with only small differences between sites, ranging from 10.3% to 11.9%. Heritabilities on the liability scale were found to be moderate to strong, and ranged between 0.24 and 0.81, with a pooled estimate of 0.43, greater than is typically associated with disease traits. Genetic correlations among sites were all substantial, between 0.71 and 0.78, and indicated that a substantial component of the genetic variation displayed within sites was common to all. The results show that field challenges can yield very good genetic information on family differences in resistance, especially when replicated over sites, which may then be developed for use in selection for breeding strains of Atlantic salmon with greater resistance to IPN. [source] Comparing density forecast models,JOURNAL OF FORECASTING, Issue 3 2007Yong Bao Abstract In this paper we discuss how to compare various (possibly misspecified) density forecast models using the Kullback,Leibler information criterion (KLIC) of a candidate density forecast model with respect to the true density. The KLIC differential between a pair of competing models is the (predictive) log-likelihood ratio (LR) between the two models. Even though the true density is unknown, using the LR statistic amounts to comparing models with the KLIC as a loss function and thus enables us to assess which density forecast model can approximate the true density more closely. We also discuss how this KLIC is related to the KLIC based on the probability integral transform (PIT) in the framework of Diebold et al. (1998). While they are asymptotically equivalent, the PIT-based KLIC is best suited for evaluating the adequacy of each density forecast model and the original KLIC is best suited for comparing competing models. In an empirical study with the S&P500 and NASDAQ daily return series, we find strong evidence for rejecting the normal-GARCH benchmark model, in favor of the models that can capture skewness in the conditional distribution and asymmetry and long memory in the conditional variance.,,Copyright © 2007 John Wiley & Sons, Ltd. [source] BIOREMEDIATIVE POTENTIAL OF CHROMULINA FREIBURGENSIS IN CULTURE FROM THE BERKELEY PITJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Dakel, S. M.1 & Mitman, G. G.2 1Department of Environmental Engineering; 2Department of Biological Sciences, Montana Tech of The University of Montana, Butte, MT 59701 USA The Berkeley Pit, part of the largest Superfund site in the United States, is an open-pit copper mine that operated from 1955 through 1982. Today, the Berkeley Pit contains approximately 1200 billion liters of metal laden water with an average pH of 2.7, and 12 grams/liter of dissolved solids. The principle dissolved ions include aluminum, arsenic, calcium, cadmium, copper, iron, potassium, magnesium, manganese, sulfates, and zinc. A species from Division Chrysophyta,Chromulina freiburgensis Dofl. was isolated from this extreme environment. This species has been tested in the laboratory through a series of controlled experiments to determine bioremediative potential. Optimal temperature was determined by monitoring growth with cell counts at temperatures ranging from 5°C to 40°C . The optimal nutrient ratio was determined by varying nitrogen (NaNO3) and phosphorus (Na2HPO4) levels. An experimental matrix varying nutrients was developed to test for bioremediative potential which included: initial and final pH measurements; initial and final Ion Chromatography Pairing,Atomic Emission Spectrometry (ICP-AES) for dissolved metals; and examination of final samples under Transmission Electron Microscopy (TEM). From these experiments, Chromulina freiburgensis was found to grow optimally in Berkeley Pit surface water with cell densities reaching ten million cells per milliliter at 10°C with additions of 50 mg NaNO3/L and 5 mg Na2HPO4/L. This large biomass was also found to increase diversity and abundance of heterotrophs. At the optimal nutrient level, this species was found to increase pH from 2.21 to 2.47 over 90 days. Significant removal of calcium, iron, nickel, and silica was observed. [source] Spatial ecology of the white-clawed crayfish in an upland stream and implications for the conservation of this endangered speciesAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 5 2008Damian H. Bubb Abstract 1.Populations of white-clawed crayfish (Austropotamobius pallipes) have undergone substantial declines across Europe. Remaining populations tend to be fragmented and in many catchments they are restricted to upland streams. Information is needed concerning their spatial ecology to assist with conservation and rehabilitation of existing fragmented populations, as well as possible reintroductions. 2.A novel method for the long-term tagging of white-clawed crayfish was used to study the spatial ecology of a white-clawed crayfish population fragment in a small, moderate-gradient upland stream. Internal passive integrated transponder (PIT) tags enabled adult crayfish (carapace length >27 mm) to be permanently tagged, each with a unique identification code and resulted in a high number of recaptures. Of 501 crayfish tagged 413 were subsequently relocated at least once. 3.Crayfish did not make extensive movements, the median annual distance moved was 84.8,m,yr,1, equivalent to annual net movement of 0.233,m,day,1, substantially less than reported in previous studies. The lower levels of movement may reflect the study encompassing all seasons, including winter, when crayfish are relatively inactive. 4.Significantly more crayfish moved downstream compared with upstream and distances moved downstream were significantly greater than those in an upstream direction. This may be linked to the relatively high gradient of the stream and a reduced passability of the abundant riffles to upstream movements of crayfish. 5.A small weir acted as a barrier within the stream, preventing upstream movements of crayfish. Even small barriers may limit the movements of white-clawed crayfish and have the potential to limit connectivity within populations and prevent expansion or recolonization. 6.The results presented suggest that fragmented populations of white-clawed crayfish in upland streams are unlikely to expand rapidly and reconnect to other population fragments, even where habitat is suitable. In establishing stream populations care should be taken to ensure that even small barriers to movement are removed unless these are intended to exclude non-native biota, especially crayfish. Copyright © 2007 John Wiley & Sons, Ltd. [source] Effect of sodium chloride on the formation and stability of n-dodecane nanoemulsions by the PIT methodASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2010Jeffery Chin Long Liew Abstract This paper provides a fundamental study of the effect of sodium chloride on the formation and stability of n-dodecane/nonionic surfactant (Brij30)/NaCl nanoemulsions produced by the phase inversion temperature (PIT) method. Nanoemulsions are an emulsion system containing droplets from 20 to 200 nm and widely used in cosmetics and pharmaceutical industries. The PIT method was chosen due to its low energy and surfactant usage to produce the nanoemulsions by heating and quenching an emulsion system. The changes of conductivity with temperatures were continuously monitored to determine phase inversion, and are found to be the same in low surfactant concentrations. PIT point was found to decrease with NaCl concentration especially from 5 to 7 wt% Brij30. At the storage temperature (20 °C), the initial droplet size decreases with NaCl concentration; however, the decrement only occurs from 4 to 7 wt% Brij30 while no nanoemulsions can be produced at 8 wt%. By adding salt, the surfactant concentration needed for the most stable nanoemulsions is reduced to 6 wt% from 7 wt%. Therefore, similar stable nanoemulsions can be produced with less surfactant in a brine system. Furthermore, most of the ageing brine-continuous nanoemulsions could be reproduced to their freshly prepared state by heating process but not for the most stable nanoemulsions. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd. [source] POTS AND PITS: DRINKING AND DEPOSITION IN LATE IRON AGE SOUTH-EAST BRITAINOXFORD JOURNAL OF ARCHAEOLOGY, Issue 2 2005MARTIN PITTS Summary. This paper considers the role of pottery in the Late Iron Age to Roman transition in south-east Britain. Traditional concern with the significance of Continental imports is rejected in favour of a more holistic and bottom-up approach giving equal emphasis to locally made forms and imports in complete assemblages. Several stages of inter-site correspondence analysis are conducted on a range of sites and assemblages in the region. Patterning pertaining to the use and deposition of both imported and local pottery vessels can be seen to contradict simplistic models for ,Romanization before conquest'. The main conclusions include evidence for the selective disposal of drinking vessels and table wares in pits, the likely widespread consumption of beer as opposed to wine, and the implied importance of indigenous social practices such as feasting and communal drinking. [source] FURTHER ASPECTS OF VAN DER WOUDE SYNDROME (CONGENITAL LOWER LIP PITS)PEDIATRIC DERMATOLOGY, Issue 1 2004Matthias Möhrenschlager M.D.. No abstract is available for this article. [source] Late-glacial remains of woolly mammoth (Mammuthus primigenius) from Shropshire, UK: stratigraphy, sedimentology and geochronology of the Condover siteGEOLOGICAL JOURNAL, Issue 4 2009J. D. Scourse Abstract In 1986 remains of an adult woolly mammoth, Mammuthus primigenius (Blumenbach), were discovered at Norton Farm Pit, Condover, south of Shrewsbury, UK. Preliminary stratigraphical investigations indicated that this individual dated to the Devensian Late-glacial Interstadial, then the first evidence for survival of mammoth in Britain following the Last Glacial Maximum. Initial radiocarbon analysis confirmed this interpretation. Subsequent excavations in 1987/1988 recovered the remains of a further three juvenile mammoth individuals. All of these remains were found in the spoil heaps of overburden (ex situ) and their true stratigraphical context had to be reconstructed from the remnants surviving in the Pit. The 1987/1988 excavations enabled stratigraphical investigation of the site and submission of samples for radiocarbon (14C) dating, including the use of ultrafiltration pretreatment for bone samples, with the aims of reconstructing the geological and palaeoenvironmental evolution of the site and the sedimentary context of the unstratified mammoth remains. These results are presented here. This investigation indicates that the woolly mammoth remains at Condover derive from a dead-ice landscape dominated by eskers, kames and kettle-hole basins, and that the sedimentary sequence in which the mammoth remains were found forms the infilling of a kettle-hole basin. The sedimentary infilling and formation of the kettle-hole basin through ice block melt-induced subsidence were syngenetic. 14C determinations indicate that basin infill was initiated prior to Greenland Interstadial 1, and probably in Greenland Stadial 2 i.e. before 14.7,ka BP and that it continued until the early Holocene, around 8,ka BP. The sedimentological and 14C data indicate that the unstratified mammoth remains can be attributed to a dark grey clayey sandy silt (Unit C1), which accumulated during the earlier part of Greenland Interstadial 1 (14 to 14.5,ka BP) within an actively subsiding slow-flowing, beaded, fluvial network characterized by channels and pools/lakes, and with relatively shallow marginal slopes. The sedimentary architecture indicates survival of the buried ice block into Greenland Interstadial 1 and final melting only towards the end of the Interstadial at ca. 12.65,ka BP. Copyright © 2009 John Wiley & Sons, Ltd. [source] BIOREMEDIATIVE POTENTIAL OF CHROMULINA FREIBURGENSIS IN CULTURE FROM THE BERKELEY PITJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Dakel, S. M.1 & Mitman, G. G.2 1Department of Environmental Engineering; 2Department of Biological Sciences, Montana Tech of The University of Montana, Butte, MT 59701 USA The Berkeley Pit, part of the largest Superfund site in the United States, is an open-pit copper mine that operated from 1955 through 1982. Today, the Berkeley Pit contains approximately 1200 billion liters of metal laden water with an average pH of 2.7, and 12 grams/liter of dissolved solids. The principle dissolved ions include aluminum, arsenic, calcium, cadmium, copper, iron, potassium, magnesium, manganese, sulfates, and zinc. A species from Division Chrysophyta,Chromulina freiburgensis Dofl. was isolated from this extreme environment. This species has been tested in the laboratory through a series of controlled experiments to determine bioremediative potential. Optimal temperature was determined by monitoring growth with cell counts at temperatures ranging from 5°C to 40°C . The optimal nutrient ratio was determined by varying nitrogen (NaNO3) and phosphorus (Na2HPO4) levels. An experimental matrix varying nutrients was developed to test for bioremediative potential which included: initial and final pH measurements; initial and final Ion Chromatography Pairing,Atomic Emission Spectrometry (ICP-AES) for dissolved metals; and examination of final samples under Transmission Electron Microscopy (TEM). From these experiments, Chromulina freiburgensis was found to grow optimally in Berkeley Pit surface water with cell densities reaching ten million cells per milliliter at 10°C with additions of 50 mg NaNO3/L and 5 mg Na2HPO4/L. This large biomass was also found to increase diversity and abundance of heterotrophs. At the optimal nutrient level, this species was found to increase pH from 2.21 to 2.47 over 90 days. Significant removal of calcium, iron, nickel, and silica was observed. [source] Evading the Pit and the Pendulum: Poe on the Process of TranscendencePOE STUDIES, Issue 1-2 2005Allan Emery First page of article [source] Foraging animals create fertile patches in an Australian desert shrublandECOGRAPHY, Issue 5 2009Alex I. James Fertile patches are created and maintained by a combination of physical and biologically-mediated processes including soil disturbance by animals. We examined the creation of fertile patches by 4 vertebrates, the greater bilby Macrotis lagotis, burrowing bettong Bettongia lesueur, European rabbit Oryctolagus cuniculus, and Gould's sand goanna Varanus gouldii within dunes, ecotones, and swales in a dunefield in arid South Australia. These animals all create pits when foraging for subterranean food resources. We hypothesized that 1) the effect of pits on litter capture would vary among landscapes and animal species, 2) larger pits would trap more litter and seed, 3) pits would contain more viable seed than the surrounding matrix, and 4) the effect of pits on soil chemistry would vary among animal species, and be greater in landscapes with more finely textured soils. We found that litter was restricted almost exclusively to the pits, and was greater in pits with larger openings. Litter capture was greater in ecotones and dunes than in swales. A total of 1307 seedlings from 46 genera germinated from litter samples taken from the pits, but no seedlings emerged from samples taken from soil surrounding the pits. Foraging pits contained significantly higher levels of total C and N than surrounding soil, and total C and N concentrations were greatest in swales and lowest in dunes. Pits contained ca 55% more mineralisable N that surface soils, and pits constructed by bilbies and bettongs contained half the concentration of mineralisable N as those of rabbits and goannas. Concentrations of mineral N and mineralisable N were also greatest in the swales. Our results demonstrate the importance of animal-created pits as nutrient sinks and sites for seedling establishment, and suggest that changes in the composition of arid zone vertebrates may have resulted in profound changes to nutrient and soil dynamics in arid Australia. [source] Three-Dimensional Geometry of Nanometer-Scale AlN Pits: A New Template for Quantum Dots?,ADVANCED MATERIALS, Issue 1 2008F. Liu The exact 3D geometry of nanometer-scale AlN pits is determined by Z -contrast imaging. The figure shows the 3D geometry of an AlN nano-pit and its corresponding GaN quantum dot. An atomic-resolution Z -contrast image is displayed in false color to clearly show the Z -contrast of the image, while the other panel displays a schematic 3D view. [source] Sperm head morphology in 36 species of artiodactylans, perissodactylans, and cetaceans (Mammalia)JOURNAL OF MORPHOLOGY, Issue 2 2005Amy Downing Meisner Abstract Detailed descriptions of mammalian sperm morphology across a range of closely related taxa are rare. Most contributions have been generalized descriptions of a few distantly related mammalian species. These studies have emphasized a generalized ungulate sperm morphology, but have not underscored several important morphological differences in ungulate sperm, such as head shape. The present study is the first to document descriptions of sperm head morphology using cold field-emission scanning electron microscopy (FE-SEM) for a large number of closely related mammalian species. In total, the sperm of 36 species in three orders: Artiodactyla (even-toed ungulates), Cetacea (whales, porpoises, and dolphins), and Perissodactyla (odd-toed ungulates) were examined to gather new information relevant to the debate about the phylogenetic placement of cetaceans relative to terrestrial ungulates. In all species examined, the sperm heads were generally flattened and ovate in shape with a distinct apical ridge, although considerable variation in sperm head shape was detected, both within and between orders. In artiodactylans, the sperm head was uniformly flat in lateral view, whereas perissodactylan and cetacean sperm heads showed a distinct posterior thickening. In both artiodactylans and perissodactylans, the mitochondria were elongate and wound in a tight helix around the midpiece, whereas in cetaceans the mitochondria were rounded and appeared to be randomly arranged around the midpiece. Additionally, prominent ridges running along the anterior,posterior axis were observed in the postacrosomal region of the sperm head in four species of cetaceans. These ridges were not observed in any of the terrestrial ungulates examined. Pits or fenestrations were detected in the postacrosomal region in most artiodactylan species examined; these structures were not detected in perissodactylans or cetaceans. The equatorial segment of the acrosome was detected in the artiodactylan species examined, tentatively identified in perissodactylans, but not found in cetaceans. Its shape and location are described for relevant taxa. The presence of a recently reported substructure within the equatorial segment (the equatorial subsegment; Ellis et al. [2002] J Struct Biol 138:187,198) was detected in artiodactylans, and its shape is described for the species examined. © 2004 Wiley-Liss, Inc. [source] Subfloor Pits and the Archaeology of Slavery in Colonial Virginia by Patricia M. SamfordAMERICAN ETHNOLOGIST, Issue 2 2009JACK GARY No abstract is available for this article. [source] Out of the Pits: Traders and Technology from Chicago to London , By C. ZaloomTHE BRITISH JOURNAL OF SOCIOLOGY, Issue 4 2007Juan Pablo Pardo-Guerra No abstract is available for this article. [source] Pits and Fissures: Etch Resistance in Prismless Enamel WallsAUSTRALIAN DENTAL JOURNAL, Issue 4 2001MF Burrow Background: In a previous study to examine the nature of etching on the walls of fissures, there was a consistent result of resistance to deep etching on parts of the walls and a zone of lesser etching on part of the walls as evidenced by the uptake of stain. The staining had been used to examine the nature of the etch pattern. The aims of this study were to define the nature of this etch resistant area. Methods: A sample of 55 teeth, both molars and premolars, were divided into three groups. In the first group the wetting of fissures by the etchant was examined; the second group tested for the effects of pellicle-cuticle-debris or air entrapment on the etching process. The final group looked at alternative mechanical treatments of the fissure prior to etching. Results: The specimens split along the fissures showed clearly that the etch resistant zone was not due to lack of contact with the etchant or the presence of a pellicle-cuticle-debris covering, but to the presence of a prismless enamel structure. This study showed that this zone inhibited tag development on the fissure walls. Conclusions: The mechanical removal of this prismless layer of enamel within the fissure system should result in an improved bonding of a fissure sealant through better tag development, in turn leading to a reduction in the failure rate of a sealant used to prevent caries. [source] Protophyllocladoxylon jingyuanense sp. nov., a Gymnospermous Wood of the Serpukhovian (Late Mississippian) from Gansu, Northwest ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 2 2010Yi ZHANG Abstract: A new species of gymnospermous fossil wood, Protophyllocladoxylon jingyuanense sp. nov., is described from the lower part of the Tsingyuan Formation (Serpukhovian/Late Mississippian), near the coal mine of Ciyao, Gansu, northwestern China. The specimen is preserved only in silicified secondary xylem, while growth rings are absent Pits in radial tracheidal walls are araucaroid in type, uniseriate, occasionally biseriate. Xylem rays are homogeneous, uniseriate, occasionally biseriate. Cross-field pits are simple, large, one to two in number. Axial parenchyma is absent. The anatomical characters and geographic distribution of Protophyllocladoxylon woods through geological ages are documented. Those species with axial parenchyma and without growth rings live in warm climate, whereas the species without axial parenchyma and with growth rings are present either in warm or cool climate. The ideal living climate for Protophyllocladoxylon woods is warm and wet. Our new species, as a fossil wood of Early Carboniferous, is likely the earliest known species of Protophyllocladoxylon. [source] Characterization and expression of AmphiBMP3,/3b gene in amphioxus Branchiostoma japonicumDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2 2010Yi Sun Bone morphogenetic proteins (BMPs) are responsible for regulating embryo development and tissue homeostasis beyond osteogenesis. However, the precise biological roles of BMP3 and BMP3b remain obscure to a certain extent. In the present study, we cloned an orthologous gene (AmphiBMP3/3b) from amphioxus (Branchiostoma japonicum) and found its exon/intron organization is highly conserved. Further, in situ hybridization revealed that the gene was strongly expressed in the dorsal neural plate of the embryos. The gene also appeared in Hatschek's left diverticulum, neural tube, preoral ciliated pit and gill slit of larvae, and adult tissues including ovary, neural tube and notochordal sheath. Additionally, real-time quantitative polymerase chain reaction (RTqPCR) analysis revealed that the expression displayed two peaks at gastrula and juvenile stages. These results indicated that AmphiBMP3/3b, a sole orthologue of vertebrate BMP3 and BMP3b, might antagonize ventralizing BMP2 orthologous signaling in embryonic development, play a role in the evolutionary precursors of adenohypophysis, as well as act in female ovary physiology in adult. [source] Morphogenesis of the node and notochord: The cellular basis for the establishment and maintenance of left,right asymmetry in the mouseDEVELOPMENTAL DYNAMICS, Issue 12 2008Jeffrey D. Lee Abstract Establishment of left,right asymmetry in the mouse embryo depends on leftward laminar fluid flow in the node, which initiates a signaling cascade that is confined to the left side of the embryo. Leftward fluid flow depends on two cellular processes: motility of the cilia that generate the flow and morphogenesis of the node, the structure where the cilia reside. Here, we provide an overview of the current understanding and unresolved questions about the regulation of ciliary motility and node structure. Analysis of mouse mutants has shown that the motile cilia must have a specific structure and length, and that they must point posteriorly to generate the necessary leftward fluid flow. However, the precise structure of the motile cilia is not clear and the mechanisms that position cilia on node cells have not been defined. The mouse node is a teardrop-shaped pit at the distal tip of the early embryo, but the morphogenetic events that create the mature node from cells derived from the primitive streak are only beginning to be characterized. Recent live imaging experiments support earlier scanning electron microscopy (SEM) studies and show that node assembly is a multi-step process in which clusters of node precursors appear on the embryo surface as overlying endoderm cells are removed. We present additional SEM and confocal microscopy studies that help define the transition stages during node morphogenesis. After the initiation of left-sided signaling, the notochordal plate, which is contiguous with the node, generates a barrier at the embryonic midline that restricts the cascade of gene expression to the left side of the embryo. The field is now poised to dissect the genetic and cellular mechanisms that create and organize the specialized cells of the node and midline that are essential for left,right asymmetry. Developmental Dynamics 237:3464,3476, 2008. © 2008 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||