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Sample records for terrestrial slug limax

  1. Spontaneous recovery of the injured higher olfactory center in the terrestrial slug limax.

    Science.gov (United States)

    Matsuo, Ryota; Kobayashi, Suguru; Murakami, Jun; Ito, Etsuro

    2010-02-08

    Of all organs and tissues in adult mammals, the brain shows the most limited regeneration and recovery after injury. This is one reason why treating neurological damage such as ischemic injury after stroke presents such a challenge. Here we report a novel mode of regeneration which the slug's cognitive center, the procerebrum, shows after surgical lesioning in the adult. It is well known that the land slug Limax possesses the capacity to demonstrate conditioned food aversion. This learning ability critically depends on the procerebrum, which is the higher olfactory center in the brain of the terrestrial mollusk. In the present study, after a 1-month recovery period post-surgical lesioning of the procerebrum we investigated whether the brain of the slug shows recovery from damage. We found that learning ability, local field potential oscillation, and the number of cells in the procerebrum (PC) all recovered spontaneously within 1 month of bilateral lesioning of the PC. Moreover, neurogenesis was enhanced in the lesioned PC. However, memory acquired before the surgery could not be retrieved 1 month after surgery although the procerebrum had recovered from injury by this time, consistent with the notion that the procerebrum is the storage site of odor-aversion memory, or deeply involved in the memory recall process. Our findings are the first to demonstrate that a brain region responsible for the associative memory of an adult organism can spontaneously reconstitute itself, and can recover its function following injury.

  2. Depletion of Serotonin Selectively Impairs Short-Term Memory without Affecting Long-Term Memory in Odor Learning in the Terrestrial Slug "Limax Valentianus"

    Science.gov (United States)

    Santa, Tomofumi; Kirino, Yutaka; Watanabe, Satoshi; Shirahata, Takaaki; Tsunoda, Makoto

    2006-01-01

    The terrestrial slug "Limax" is able to acquire short-term and long-term memories during aversive odor-taste associative learning. We investigated the effect of the selective serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) on memory. Behavioral studies indicated that 5,7-DHT impaired short-term memory but not long-term memory. HPLC…

  3. Length of the memory retention period depends on the extent of protein synthesis in the terrestrial slug Limax.

    Science.gov (United States)

    Suenaga, Yuko; Matsuo, Ryota

    2016-09-06

    The terrestrial slug Limax can form an odor-aversion memory by the single simultaneous presentation of a food odor and an aversive stimulus. We have previously demonstrated that the long-term retention of this memory was impaired by a high-dose injection of a protein synthesis inhibitor 30min prior to the conditioning. However, the onset of amnesia was delayed if the dose of the inhibitor was reduced or a less potent protein synthesis inhibitor was used. We thus speculated that the persistence of memory depends on the amount of newly synthesized protein following learning. In the present study, we further elaborated on this idea by injecting a high dose of anisomycin at different timings before or after conditioning, and tested the memory retention at 1, 2, 3, 7, or 14days after the conditioning. We found that the injection of anisomycin 6h before, or 1h after the conditioning had no effect on memory retention for 7days, and an injection at 30min before and just following the conditioning impaired the memory retention at 3days. Interestingly, the injection at 3h before and 30min after the conditioning did not impair the retention at 3days but did impair retention at 7days. Taking into account the time course of protein synthesis inhibition in the brain, our results further support the idea that the memory retention period is dependent on the amount of protein synthesized following memory acquisition. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Internal Representation and Memory Formation of Odor Preference Based on Oscillatory Activities in a Terrestrial Slug

    Science.gov (United States)

    Sekiguchi, Tatsuhiko; Furudate, Hiroyuki; Kimura, Tetsuya

    2010-01-01

    The terrestrial slug "Limax" exhibits a highly developed ability to learn odors with a small nervous system. When a fluorescent dye, Lucifer Yellow (LY), is injected into the slug's body cavity after odor-taste associative conditioning, a group of neurons in the procerebral (PC) lobe, an olfactory center of the slug, is labeled by LY. We examined…

  5. Olfactory Memory Storage and/or Retrieval Requires the Presence of the Exact Tentacle Used During Memory Acquisition in the Terrestrial Slug Limax.

    Science.gov (United States)

    Koga, Yurika; Matsuo, Yuko; Matsuo, Ryota

    2016-02-01

    Terrestrial pulmonates can form odor-aversion memories once a food odor is presented in combination with an aversive stimulus. Most of the olfactory information ascends via a tentacular ganglion located in the tip of the two pairs of tentacles, and is then transmitted to the higher olfactory center, the procerebrum. The procerebrum is the locus of memory storage and has been shown to be necessary for odor-aversion learning. However, it is unknown whether the procerebrum is the sole locus in which the memory engram resides. By exploiting the regenerative ability of tentacles, here we investigated whether tentacles function merely in transmitting olfactory information to the procerebrum, or constitute a part of the memory engram. We showed that after removal of the tentacles used during memory acquisition, slugs were unable to retrieve the memory, even if these tentacles were regenerated sufficiently to subserve memory function. Our results support the view that tentacles are more than conduits of odor information; they also participate in the formation of the memory engram.

  6. Pedal sole immunoreactive axons in terrestrial pulmonates: Limax, Arion, and Helix.

    Science.gov (United States)

    Longley, Roger D

    2014-02-01

    A century ago histological techniques such as formic acid-gold chloride showed the nerve morphology of the pedal sole in Limax and Helix. There have been no similar descriptions since then of the central nervous system relevant to locomotory pedal waves in the foot of slugs and snails. Topical application of 5-HT affects locomotory waves, but the innervation of the pedal sole with 5-HT axons is not known. Three-dimensional morphology of pedal axons in terrestrial pulmonate embryos is shown herein with modern histological techniques using antibodies and the confocal microscope. In Limax maximus, pedal ganglia are shown with Tritonia pedal peptide (TPep) antibodies. Ladder-like cross bridges in the pedal sole are shown with antibodies to both TPep and 5-HT. In Arion ater, pedal ganglia neurons and their axons that form a plexus in the pedal sole are shown with 5-HT antibodies. In Helix aspersa, 5-HT immunoreactive pedal ganglia neurons and a developing pedal sole axon plexus are seen as in A. ater. Axons in this plexus that grow across the pedal sole can be seen growing into pre-existing nerves. No peripheral 5-HT neurons were identified in these three species. This immunoreactive plexus to 5-HT antibodies in A. ater and H. aspersa spreads over the pedal sole epithelium. Axons immunoreactive to 5-HT antibodies in A. ater and H. aspersa extend the length of the foot, primarily in the rim, so that activity in these axons cannot provide local patterned input to produce locomotory waves, but may provide modulatory input to pedal sole muscles.

  7. Investigation of the Fatty Acid Contents of Edible Snails Helix lucorum, Eobania vermiculata and Non-Edible Slug Limax flavus

    Directory of Open Access Journals (Sweden)

    İhsan Ekin

    2017-11-01

    Full Text Available The purpose of this work is to reveal the fatty acid composition of phospholipids, neutral and total lipid content of edible land snails Helix lucorum, Eobania vermiculata and non-edible land slug Limax flavus(Gastropoda: Pulmonata. The analyses revealed that the snails and slug are rich in C16:0, C18:0, C18:1ω9 and C18:2ω6 acids. Phospholipid fractions contained very high amounts of C20:4ω6 (15.37% in H. lucorum, 12.37% in E. vermiculata and 8.59% in L. flavus which is the most importantprecursor of eicosanoids. The level of ΣPUFA, in edible snails, was found to be higher than ΣSFA and ΣMUFA. However, in the slug, ΣMUFA level was higher than ΣSFA and ΣPUFA levels in neutral and total lipid contents. Ʃω6 / Ʃω3 (Omega 6 / Omega 3 ratio was defined to be very high in the phospholipid of H. lucorum, E. vermiculata and L. flavus; 6.07, 8.29 and 5.39, respectively. Furthermore, the study showed that all three species are valuable sources of omega 6 and essential fatty acids; C18:2ω6 and C18:3ω6 .

  8. Terrestrial slugs (Gastropoda, Pulmonata in the NATURA 2000 areas of Cyprus island

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    Katerina Vardinoyannis

    2012-03-01

    Full Text Available Terrestrial slugs of the Island of Cyprus were recently studied in the framework of a study of the whole terrestrial malacofauna of the island. The present work was carried out in the Natura 2000 conservation areas of the island in 155 sampling sites over three years (2004–2007. Museum collections as well as literature references were included. In total six species are present in the Natura 2000 areas of the island, belonging to three families: Limacidae, Agriolimacidae and Milacidae. One of the species, Milax riedeli, is a new record for the island. The distribution of the species across the island and in the surrounding areas is discussed.

  9. Cold tolerance and freeze-induced glucose accumulation in three terrestrial slugs

    DEFF Research Database (Denmark)

    Slotsbo, Stine; Hansen, Lars Monrad; Jordaens, Kurt

    2012-01-01

    Cold tolerance and metabolic responses to freezing of three slug species common in Scandinavia (Arion ater, Arion rufus and Arion lusitanicus) are reported. Autumn collected slugs were cold acclimated in the laboratory and subjected to freezing conditions simulating likely winter temperatures...

  10. DNA barcodes and phylogenetic affinities of the terrestrial slugs Arion gilvus and A. ponsi (Gastropoda, Pulmonata, Arionidae

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    Karin Breugelmans

    2013-12-01

    Full Text Available The Iberian Peninsula is a region with a high endemicity of species of the terrestrial slug subgenus Mesarion. Many of these species have been described mainly on subtle differences in their proximal genitalia. It therefore remains to be investigated 1 whether these locally diverged taxa also represent different species under a phylogenetic species concept as has been shown for other Mesarion species outside the Iberian Peninsula, and 2 how these taxa are phylogenetically related. Here, we analysed DNA sequence data of two mitochondrial (COI and 16S genes, and of the nuclear ITS1 region, to explore the phylogenetic affinities of two of these endemic taxa, viz. Arion gilvus Torres Mínguez, 1925 and A. ponsi Quintana Cardona, 2007. We also evaluated the use of these DNA sequence data as DNA barcodes for both species. Our results showed that ITS did not allow to differentiate among most of the Mesarion molecular operational taxonomic units (MOTUs / morphospecies in Mesarion. Yet, the overall mean P-distance among the Mesarion MOTUs / morphospecies for both mtDNA fragments (16.7 % for COI, 13 % for 16S was comparable to that between A. ponsi and its closest relative A. molinae (COI: 14.2 %; 16S: 16.2 % and to that between A. gilvus and its closest relative A. urbiae (COI: 14.4 %; 16S: 13.4 %. Hence, with respect to mtDNA divergence, both A. ponsi and A. gilvus, behave as other Mesarion species or putative species-level MOTUs and thus are confirmed as distinct ‘species’.

  11. Initiation of slug flow

    Energy Technology Data Exchange (ETDEWEB)

    Hanratty, T.J.; Woods, B.D. [Univ. of Illinois, Urbana, IL (United States)

    1995-12-31

    The initiation of slug flow in a horizontal pipe can be predicted either by considering the stability of a slug or by considering the stability of a stratified flow. Measurements of the shedding rate of slugs are used to define necessary conditions for the existence of a slug. Recent results show that slugs develop from an unstable stratified flow through the evolution of small wavelength waves into large wavelength waves that have the possibility of growing to form a slug. The mechanism appears to be quite different for fluids with viscosities close to water than for fluids with large viscosities (20 centipoise).

  12. Distribution and genetic diversity of the terrestrial slugs Arion lusitanicus Mabille, 1868 and Arion rufus (Linnaeus, 1758) in Poland based on mitochondrial DNA.

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    Soroka, Marianna; Kozłowski, Jan; Wiktor, Andrzej; Kałuski, Tomasz

    2009-01-01

    The slugs Arion lusitanicus and Arion rufus inhabit ecologically degraded areas and are serious vegetation pests. In recent years, new localities of these species have been found in various parts of Poland. Here we study the morphology of 90 specimens from 9 populations of slugs. The morphology of the genital system allowed for the identification of 60 A. lusitanicus specimens from 6 populations and 30 A. rufus individuals from another 3 localities. In order to describe their genetic diversity at the level of the individual, population, and species, we compared sequences of the mitochondrial cytochrome oxidase subunit I (cox1) gene. The morphological analysis revealed that each of the studied populations comprised a single species, which was also confirmed by the molecular assay. We obtained 674-bp sequences of the cox1 gene for each species that showed a total of eight haplotypes. The genetic diversity of A. lusitanicus individuals ranged from 0.5% to 2.1%, whereas that of A. rufus was twice as low: 0.4-1.0%. The difference between the two species within the cox1 gene was at the level of 12%. Three A. lusitanicus and two A. rufus populations were found to be monomorphic. Large inter-population variability was found within each of the studied species, which suggests that the Polish populations of A. lusitanicus may have originated from repeated, separate introductions arriving from various parts of Europe.

  13. LiMAx Test Improves Diagnosis of Chemotherapy-Associated Liver Injury Before Resection of Colorectal Liver Metastases.

    Science.gov (United States)

    Lock, Johan F; Westphal, Tilman; Rubin, Tom; Malinowski, Maciej; Schulz, Antje; Jara, Maximilian; Bednarsch, Jan; Stockmann, Martin

    2017-09-01

    Chemotherapy of colorectal liver metastases (CLMs) prior to liver resection implies the risk of chemotherapy-associated liver injury, leading to increased postoperative morbidity and mortality OBJECTIVE: The aim of this study was to evaluate the LiMAx (liver maximum capacity) test for diagnosis of chemotherapy-associated liver injury. This was a retrospective analysis of patients with CLMs, prior to liver resection. We performed preoperative assessment of liver function using biochemical parameters and the LiMAx test. The individual history of chemotherapy within 12 months, including regimen, number of cycles, and therapy-free interval were collected, and histopathological evaluation of tumor-free liver tissue was performed in resected patients. A total of 204 patients were included, of whom 127 (62%) had received previous chemotherapy. The LiMAx test was worse after chemotherapy (340 ± 95 vs. 391 ± 82 µg/kg/h; p < 0.001). Impaired LiMAx results (<315 µg/kg/h) were determined in 49% of patients after chemotherapy, and no effects of chemotherapy, liver steatosis or fibrosis on biochemical parameters were observed. LiMAx impairment was dependent on the number of oxaliplatin cycles, the therapy-free interval, and obesity in multivariate analysis. In addition, the LiMAx test was worse in patients with relevant steatosis, fibrosis and steatohepatitis. Patients with an impaired LiMAx showed sufficient regeneration during chemotherapy cessation when surgery was postponed (272 ± 57 - 348 ± 72 µg/kg/h; p = 0.003). The LiMAx test enables non-invasive preoperative diagnosis of chemotherapy-associated liver injury. Preoperative performance of the LiMAx test can augment surgical strategy and timing of surgery after previous chemotherapy, thus avoiding increased postoperative morbidity.

  14. Use grading of classified slugs

    Energy Technology Data Exchange (ETDEWEB)

    Crane, P.W.; Lewis, E.V.

    1994-08-11

    This memorandum discusses an agreement reached by members of the Technical Division, Operating Department, and Technical Department as to groups of slug classifications to be assigned to regions of varying degrees of severity of exposure in the pile. Estimates of the slugs to be available in the groups established are included herein, together with a plan for allocation to the pile.

  15. Correlation between plasma endothelin-1 levels and severity of septic liver failure quantified by maximal liver function capacity (LiMAx test. A prospective study.

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    Magnus F Kaffarnik

    Full Text Available To investigate the relationship between the degree of liver dysfunction, quantified by maximal liver function capacity (LiMAx test and endothelin-1, TNF-α and IL-6 in septic surgical patients.28 septic patients (8 female, 20 male, age range 35-80y were prospectively investigated on a surgical intensive care unit. Liver function, defined by LiMAx test, and measurements of plasma levels of endothelin-1, TNF-α and IL-6 were carried out within the first 24 hours after onset of septic symptoms, followed by day 2, 5 and 10. Patients were divided into 2 groups (group A: LiMAx ≥100 μg/kg/h, moderate liver dysfunction; group B: LiMAx <100 μg/kg/h, severe liver dysfunction for analysis and investigated regarding the correlation between endothelin-1 and the severity of liver failure, quantified by LiMAx test.Group B showed significant higher results for endothelin-1 than patients in group A (P = 0.01, d5; 0.02, d10. For TNF-α, group B revealed higher results than group A, with a significant difference on day 10 (P = 0.005. IL-6 showed a non-significant trend to higher results in group B. The Spearman's rank correlation coefficient revealed a significant correlation between LiMAx and endothelin-1 (-0.434; P <0.001, TNF-α (-0.515; P <0.001 and IL-6 (-0.590; P <0.001.Sepsis-related hepatic dysfunction is associated with elevated plasma levels of endothelin-1, TNF-α and IL-6. Low LiMAx results combined with increased endothelin-1 and TNF-α and a favourable correlation between LiMAx and cytokine values support the findings of a crucial role of Endothelin-1 and TNF-α in development of septic liver failure.

  16. Applicability of the black slug Arion ater for monitoring exposure to polycyclic aromatic hydrocarbons and their subsequent bioactivation into DNA binding metabolites

    NARCIS (Netherlands)

    Hamers, T.; Kalis, E.J.J.; Berg, van den J.H.J.; Maas, L.M.; Schooten, van F.J.; Murk, A.J.

    2004-01-01

    The applicability of terrestrial black slugs Arion ater (Mollusca, Gastropoda) was studied for biomonitoring environmental exposure to polycyclic aromatic hydrocarbons (PAHs). In laboratory experiments, slugs were orally exposed to benzo[a]pyrene (BaP) for a short term (3 days) or a long term (119

  17. Slug promoted vasculogenic mimicry in hepatocellular carcinoma

    OpenAIRE

    Sun, Dan; Sun, Baocun; Liu, Tieju; Zhao, Xiulan; Che, Na; Gu, Qiang; Dong, Xueyi; Yao, Zhi; Li, Rui; Li, Jing; Chi, Jiadong; Sun, Ran

    2013-01-01

    Vasculogenic mimicry (VM) refers to the unique capability of aggressive tumour cells to mimic the pattern of embryonic vasculogenic networks. Epithelial?mesenchymal transition (EMT) regulator slug have been implicated in the tumour invasion and metastasis of human hepatocellular carcinoma (HCC). However, the relationship between slug and VM formation is not clear. In the study, we demonstrated that slug expression was associated with EMT and cancer stem cell (CSCs) phenotype in HCC patients. ...

  18. Relationship Between Slugging Pressure and Brittle Fracture ...

    African Journals Online (AJOL)

    The hardness of the slugs was determined and taken as measure of the hardness of the resulting granules. The following tableting parameters were measured for the final tablets - tensile strength (T), packing fraction (Pf) and the brittle fracture index (BFI). Results - A high slugging load was associated with the formation of ...

  19. Slug promoted vasculogenic mimicry in hepatocellular carcinoma.

    Science.gov (United States)

    Sun, Dan; Sun, Baocun; Liu, Tieju; Zhao, Xiulan; Che, Na; Gu, Qiang; Dong, Xueyi; Yao, Zhi; Li, Rui; Li, Jing; Chi, Jiadong; Sun, Ran

    2013-08-01

    Vasculogenic mimicry (VM) refers to the unique capability of aggressive tumour cells to mimic the pattern of embryonic vasculogenic networks. Epithelial-mesenchymal transition (EMT) regulator slug have been implicated in the tumour invasion and metastasis of human hepatocellular carcinoma (HCC). However, the relationship between slug and VM formation is not clear. In the study, we demonstrated that slug expression was associated with EMT and cancer stem cell (CSCs) phenotype in HCC patients. Importantly, slug showed statistically correlation with VM formation. We consistently demonstrated that an overexpression of slug in HCC cells significantly increased CSCs subpopulation that was obvious by the increased clone forming efficiency in soft agar and by flowcytometry analysis. Meantime, the VM formation and VM mediator overexpression were also induced by slug induction. Finally, slug overexpression lead to the maintenance of CSCs phenotype and VM formation was demonstrated in vivo. Therefore, the results of this study indicate that slug induced the increase and maintenance of CSCs subpopulation and contributed to VM formation eventually. The related molecular pathways may be used as novel therapeutic targets for the inhibition of HCC angiogenesis and metastasis. © 2013 The Authors. Journal of Cellular and Molecular Medicine Published by Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

  20. Spontaneous occurrence of antibodies against pathogenic amoebae of the limax group in domestic animals.

    Science.gov (United States)

    Cerva, L

    1981-01-01

    Sera of 1 218 animals were examined using indirect haemagglutination reaction with antigens of Naegleria fowleri and Acanthamoeba culbertsoni. Rabbit sera (214 samples) gave negative reaction with both antigens. Bovine sera (593 samples) reacted positively in 1.5%, particularly with the antigen of A. culbertsoni. Out of the 411 pigs examined 12% were positive with one or both of the antigens. In one of the pig farms of a modern type the positivity with one or both of the antigens. In one of the pig farms of a modern type the positivity was as much as 32.2%. The titres of positive animal sera have never been higher than 1 : 320. The amoebae of the limax group do not seem to be involved in the pathogenesis of diseases of cattle and rabbits. A sporadic occurrence of peracute cases is possible. In case of a sudden death, animals with symptoms of encephalitis or pneumonia should be examined for the presence of amoebae. Hypersensitivity should be considered as a possible cause of pig diseases.

  1. OIL SLUGS FOR PRODUCTION OF PISTON RING

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    V. F. Bevza

    2008-01-01

    Full Text Available The developed technological process of continuously cyclic casting by frosting allows to receive high-quality hollow cylindrical slugs of cast iron for production of critical parts. 

  2. The gastropod menace: slugs on Brassica plants affect caterpillar survival through consumption and interference with parasitoid attraction

    Science.gov (United States)

    Terrestrial molluscs and insect herbivores play a major role as plant consumers in a number of ecosystems, but their direct and indirect interactions have hardly been explored. The omnivorous nature of slugs makes them potential disrupters of predator-prey relationships, as a direct threat to small ...

  3. Two-Fluid Model for 1D Gas-Liquid Slug Flows: Realizable Mean Slug Characteristics

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    M. Gourma

    2015-06-01

    Full Text Available A two-fluid model is used to predict hydrodynamic characteristics of gas water two phase slug flows in horizontal pipes. Mathematical models are averaged based forms of balance laws with algebraic source terms. Predictions of transient solutions of such systems rely on accurate evaluations of speeds and scales of discontinuities generated by the flow conditions. Slug flows are characterized through slug frequencies, slug lengths and slug translational velocities. These are the fundamental quantities that one has to estimate in order to assess the validity of the model and the numerical method in use. A two fluid 1D model for slug flows along with an AUSMDV* numerical scheme is able to predict correct translational speeds, lengths scales and frequencies of slugs. An adaptive mesh refinement AMR procedure based on Kelvin-Helmholtz stability condition as an indicator for refinement is used to speed up simulations. The marginal Kelvin-Helmholtz stability condition is also introduced to estimate slug body length.

  4. Mitigation of terrain induced slugging using mixer devices

    NARCIS (Netherlands)

    Brasjen, B.J.; Veltin, J.; Hansen, J.H.

    2014-01-01

    The present work focuses on experimental evidence of slug mitigation via various devices. The slug mitigation potential of a number of mixers was tested using a laboratory scale air/water setup to compare their effect on the incoming slugs just upstream of the separator inlet. Dedicated methods and

  5. Riser slugging - a mathematical model and the practical consequences

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    Svein I. Sagatun

    2005-04-01

    Full Text Available This article presents a novel approach to estimate severe riser slug build up time and consequently the slug period. The slug model is based on a simplified mechanical model. This information has subsequently been used to illustrate the effects of the traditional actions to prevent severe riser slugging. New field data from an offshore floating production platform and large scale experimental data are included. The experimental set up is described in detail. The estimate on the slug built up time provided by the simplified model matches data from the experiments, the full scale data and data in relevant references.

  6. NUCLEAR REACTOR SLUG PROVIDED WITH THERMOCOUPLE

    Science.gov (United States)

    Kanne, W.R.

    1958-10-14

    A temperature measuring apparatus is described for use in a reactor. In this invention a cylindrlcal fuel slug is provided with an axial bore in which is disposed a thermocouple. The lead wires extend to a remote indicating device which indicates the temperature in the fuel element measured by the thermocouple.

  7. EBR-II fuel slug casting experience

    Energy Technology Data Exchange (ETDEWEB)

    Wilkes, C. W.; Batte`, G. L.; Tracy, D. B.; Griffiths, V.

    1987-07-01

    The following paper presents a chronology of EBR-II fuel slug casting experience. Starting with the early vendor campaigns, the paper explains how production of EBR-II fuel, as well as fuel for off-site reactors, has evolved. The production facilities (i.e., EFL, Room 20, FMF, etc.) and casting techniques are discussed in detail. The paper also presents how the original casting operations have improved and the problems encountered as the techniques were developed. Extensive descriptions and data are given on the major experimental programs currently ongoing at EBR-II. Major programs include the IFR lead subassemblies, large diameter slugs, IFR metal fuel RBCB, and the FFTF subassembly program. Concluding the paper is a brief description of future development projects being considered and a summation of how EBR-II Fuels and Materials has been able to overcome various administration obstacles (i.e., improved security and safeguards measures) to continue to meet the increasing demands of fuel production while maintaining an aggressive and active research and development program in fuel slug production.

  8. ER? suppresses slug expression directly by transcriptional repression

    OpenAIRE

    Ye, Yin; Xiao, Yi; Wang, Wenting; Yearsley, Kurtis; Gao, Jian-Xin; Barsky, Sanford H.

    2008-01-01

    Two of the most common signalling pathways in breast cancer are the ER (oestrogen receptor) ligand activation pathway and the E-cadherin snai1 slug EMT (epithelial?mesenchymal transition) pathway. Although these pathways have been thought to interact indirectly, the present study is the first to observe direct interactions between these pathways that involves the regulation of slug expression. Specifically we report that ligand-activated ER? suppressed slug expression directly by repression o...

  9. Reverse Isolation and Backaction of the SLUG Microwave Amplifier

    Science.gov (United States)

    Thorbeck, T.; Zhu, S.; Leonard, E.; Barends, R.; Kelly, J.; Martinis, John M.; McDermott, R.

    2017-11-01

    An ideal preamplifier for qubit measurement must not only provide high gain and near quantum-limited noise performance, but also isolate the delicate quantum circuit from noisy downstream measurement stages while producing negligible backaction. Here, we use a superconducting low-inductance undulatory galvanometer (SLUG) microwave amplifier to read out a superconducting transmon qubit, and we characterize both reverse isolation and measurement backaction of the SLUG. For appropriate dc bias, the SLUG achieves reverse isolation that is better than that of a commercial cryogenic isolator. Moreover, SLUG backaction is dominated by thermal emission from dissipative elements in the device. When the SLUG is operated in pulsed mode, it is possible to characterize the transmon qubit using a measurement chain that is free from cryogenic isolators or circulators with no measurable degradation of qubit performance.

  10. SLUG: A New Way to Stochastically Light Up Galaxies

    Science.gov (United States)

    Fumagalli, M.; da Silva, R.; Krumholz, M.; Bigiel, F.

    2011-06-01

    We present SLUG, a new code to "Stochastically Light Up Galaxies". SLUG populates star clusters by randomly drawing stars from an initial mass function (IMF) and then following their time evolution with stellar models and an observationally-motivated prescription for cluster disruption. For a choice of star formation history, metallicity, and IMF, SLUG outputs synthetic photometry for clusters and field stars with a proper treatment of stochastic star formation. SLUG generates realistic distributions of star clusters, demonstrating the range of properties that result from finite sampling of an IMF and a random distribution of ages. The simulated data sets provide a quantitative means to address open problems in studies of star formation in galaxies and clusters, such as a test for IMF variations that are suggested by the systematic deficiency in the Hα/UV ratio in outer disks or in dwarf galaxies. SLUG will be made publicly available through the website: http://sites.google.com/site/runslug/.

  11. Conduit speed limit promotes formation of explosive `super slugs'

    Science.gov (United States)

    Llewellin, E. W.; Burton, M. R.; Mader, H. M.; Polacci, M.

    2014-12-01

    Strombolian activity - characterized by discrete, impulsive explosions - is common at basaltic volcanoes. The explosions are caused by the arrival, at the volcanic vent, of over-pressured `slugs' of magmatic gas, which have ascended the volcanic conduit. We present data from large-scale analogue experiments which reveal a previously-undescribed process which promotes the formation of large, highly over-pressured `super slugs'. We propose that these large slugs may drive the most violent Strombolian eruptions. Experiments were performed at the Large Analogue Volcano Apparatus at Durham University, UK, which comprises a 13m tall, 24cm diameter transparent conduit, surmounting a reservoir of analogue magma held at constant pressure. We simulate a vesiculation event deep in the sub-volcanic plumbing system by fluxing gas into the reservoir. Magma analogues with a range of viscosities are used, giving slug Reynolds numbers in the range 16 to 140,000. At moderate-to-high Reynolds number, we find that the gas rapidly self-organizes to form a conduit-filling lead slug; this slug ascends the column slowly, at a velocity limited by the flux of the falling film of liquid around it. Trailing bubbles, which ascend through the wake of the lead slug, rise much more rapidly. As they catch and coalesce with the lead slug, it grows and becomes increasingly over-pressured. This mechanism causes large slugs to form rapidly and we propose that it underpins the formation of the very large slugs that are responsible for the most explosive strombolian eruptions.

  12. Dynamics of liquid slug using particle image velocimetry technique

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    Siddiqui, M. I.; Aziz, A. Rashid A.; Heikal, M. R.

    2016-11-01

    Two phase liquid-gas slug flow is a source of vibration and fatigue on pipe walls and downstream equipment. This paper examines the effect of inlet conditions on the stream-wise velocity profiles and on the shear stresses induced by the liquid phase on the pipe wall during the slug flow. Instantaneous velocity vector fields of the liquid-gas (water-air) slug flow regime were obtained using particle image velocimetry (PIV) technique at various inlet conditions. A 6-m long Plexiglas pipe having an internal diameter 74-mm with a slight inclination of about 1.16° was considered for the visualization of the flow pattern. Test section was employed at a point 3.5m from the inlet, mounted with optical correction box filled with water to minimize the curvature effect of pipe on the PIV snapshots. Stream-wise velocity profiles are obtained at the wake of the liquid slug and the effect of inlet conditions were analyzed. A direct relationship was observed in between superficial gas velocity and the liquid stream-wise velocity at wake section of the slug flow. Further, the lower wall shear stresses were obtained using PIV velocity profiles at liquid film and the slug wake sections in a unit slug. The wall shear stress remained higher in the liquid slugy body as compared to the liquid film. Moreover, an increase in the wall shear stress was observed by increasing the gas superficial velocities.

  13. Slug control system; Sistema de controle de golfadas

    Energy Technology Data Exchange (ETDEWEB)

    Borges Filho, Alvaro de Miranda; Meira, Marco Antonio Alves de; Vaz, Celio Eduardo Martins [PETROBRAS, Macae, RJ (Brazil). Unidade de Negocios da Bacia de Campos

    2004-07-01

    Due to the characteristics of flow, gas can separate from oil in the pipelines and risers that link subsea manifolds to production offshore platforms, forming liquid and gas slugs in the production separator. Liquid slugs can cause overflow in the separators. Gas slugs can cause burning in the flare due to the limitation in the turbo-compressors acceleration. In both cases the consequences are loss of production or shut-downs. This paper presents a Slug Control System designed to attenuate severe gas and liquid flow variations. The system consist of a control valve installed in the separator inlet, transmitters, a controller, control algorithm and a monitoring station. This system is operating since October 2003 in a production offshore platform, in Campus Basin, Brazil, with excellent results, reducing the gas burning in 45% without oil production loss. (author)

  14. Seed dressings to control slug damage in oilseed rape.

    Science.gov (United States)

    Simms, Louise C; Mullins, Christopher E; Wilson, Michael J

    2002-07-01

    Slugs are major pests of oilseed rape that are poorly controlled by conventional bait pellets. A series of laboratory experiments investigated the potential of seed-dressings to control slug damage in this crop. Four compounds: metaldehyde, methiocarb, cinnamamide and 3,5-dimethoxycinnamic acid (DMCA) were tested at a range of doses for phytotoxicity and ability to reduce damage by Deroceras reticulatum (Müller). Metaldehyde and methiocarb were not phytotoxic at any doses, whereas all doses of cinnamamide and DMCA were. All compounds reduced slug damage, but metaldehyde and methiocarb consistently performed better than cinnamamide and DMCA. Metaldehyde and methiocarb seed-dressings were compared with baited pellets containing the same active ingredients at recommended field doses. The seed-dressings protected plants from damage by D reticulatum and Arion subfuscus (Draparnaud) as well as, or better than, baited pellets. We therefore recommend that metaldehyde and methiocarb should be field-tested as seed dressings to control slugs in oilseed rape.

  15. Expression of EMT Markers SLUG and TWIST in Breast Cancer.

    Science.gov (United States)

    Grzegrzolka, Jedrzej; Biala, Martyna; Wojtyra, Patrycja; Kobierzycki, Christopher; Olbromski, Mateusz; Gomulkiewicz, Agnieszka; Piotrowska, Aleksandra; Rys, Janusz; Podhorska-Okolow, Marzena; Dziegiel, Piotr

    2015-07-01

    The epithelial-mesenchymal transition (EMT) has been observed in progression of in situ breast cancer to the invasive form and might be initiated by snail family zinc finger 2 (SLUG) and twist family bHLH transcription factor 1 (TWIST) protein overexpression. During this phenomenon, cells lose their epithelial phenotype and acquire mesenchymal features. The aim of the study was to examine the association of EMT markers SLUG and TWIST with clinicopathological data and the possibility of using these proteins as prognostic markers of breast cancer. Immunohistochemical analysis (IHC) of SLUG and TWIST expression was performed on archival paraffin samples of 19 cases with fibrocystic breast changes (control group), 148 cases of invasive ductal breast cancer (IDC) and 26 of invasive lobular breast cancer (ILC). Laser capture microdissection for isolation of cells from 17 frozen samples of IDC was employed and subsequently SLUG and TWIST mRNA expression in cancer and stromal cells was detected separately by real-time polymerase chain reaction. SLUG and TWIST expression in IDC was significant higher in stromal cells regardless of the method of quantification used (p<0.001 for SLUG mRNA, and p<0.0001 for SLUG IHC, TWIST IHC and TWIST mRNA expression). Positive correlation of SLUG and TWIST protein and mRNA expression was observed in stromal cells of IDC (r=0.347; p<0.0001 and r=0.704; p<0.01, respectively). Expression of TWIST protein in IDC was higher in cancer cells of cases with shorter event-free survival period, as well as in stromal cells of cases with shorter overall survival period (p<0.05 for both). Stromal cells could play a role in the regulation of EMT in breast cancer. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  16. Modeling and Experiments of Severe Slugging in a Riser System

    Directory of Open Access Journals (Sweden)

    Lin Wang

    2016-01-01

    Full Text Available A transient mathematical model based on continuity equations for liquid and gas phases, with a momentum equation for the mixture, was developed, and numerical solutions and simulations corresponding to severe slugging in pipeline-riser system were presented, and the results were compared with the experimental data to verify the mathematical model. In numerical solutions, backward Euler schemes were adopted as predictors and trapezoidal methods were used as correctors. Variable time steps were employed for higher computational efficiency and accuracy in the integration. Experiments of severe slugging characteristics were performed, and the simulation results of the cycle periods and bottom pressure were compared with experimental values. Finally, the calculation results of detailed characteristics were analyzed thoroughly. The results show that the developed mathematical model can accurately predict the cycle time and the detailed characteristics of severe slugging. Under the experimental conditions, the liquid slug length can reach 1.6 times the height of the riser, and the maximum instantaneous gas velocity of outlet is 50 times the inlet gas velocity, and the maximum instantaneous liquid velocity of outlet is 28 times the inlet liquid velocity, having important implications for the hazard assessment of severe slugging.

  17. Dual-slug miscible displacement of Bradford crude. Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Stahl, C.D.

    1965-07-01

    An examination of the results presented in graphs showing (1) effect of buffer slug viscosity on isopropyl alcohol-free oleic phase recovery, and (2) viscosity ratio (Bradford crude/buffer slug), indicate that phase behavior was a more critical parameter than viscosity ratio in determining the recovery efficiency of the buffer slug for the systems studied. Solvent-free oleic phase recovery increased 2.6 times as the viscosity ratio was increased from 0.8 to 36. Pure oil recovery was greatest for the most adverse viscosity ratio. Of all the buffer materials tested, propane gave a higher pure oil recovery than an amyl alcohol for a viscosity ratio of 1.09. It should be emphasized that in the combination slug process one is concerned with two aspects of phase behavior. First, the in-place oil is miscibly displaced by the buffer slug which is usually immiscible with the brine in the core. Then, on the injection of isopropyl alcohol, a completely miscible process occurs at the rear of the buffer fluid, as the brine-drive alcohol removes all of the remaining reservoir fluids under ideal conditions. The ternary diagrams illustrated provide an indication only to the mechanism of the latter process.

  18. Severe Slugging in Air-Water Hybrid Riser System

    Directory of Open Access Journals (Sweden)

    Jing Gong

    2014-11-01

    Full Text Available In the subsea pipeline gathering system, severe slugging flow is prone to occur. Severe slugging flow brings major threat to production and flow assurance in oil and gas industry due to periodical pressure oscillation and large liquid volume. Currently many researchers pay much more attention on L-shaped riser, catenaries, and S-shaped riser; little research has been made on hybrid riser, which is applied in the Africa West and Gulf of Mexico oil fields. Flow characteristics simulation for hybrid riser is made in this paper, using the one-dimensional and quasi-equilibrium model to simulate not only the riser-base pressure, severe slugging period, and the liquid slug length of the whole system but also base-pressure in the flexible pipe section. The calculated results match well with the experiment data. Besides, the influence of flexible pipe to the severe slugging characteristics of hybrid riser system is analyzed, which are significant for the determination of riser structure.

  19. EARTHWORMS AND THEIR IMPACT ON SLUG CONTROL

    Science.gov (United States)

    Increases in the anecic earthworm species, Lumbricus terrestris L., have occurred in western Oregon grass fields due to increases in surface residue since the phase-out of open field burning. The use of earthworm toxic chemicals has been reduced through concerns for other important vertebrate and in...

  20. Taxonomic determination of five groups of slugs and life cycle studies of the prevalent group in a commercial crop of alstroemeria in the loca lit y of Madrid, Cundinamarca Determinación taxonómica de cinco grupos de babosas y estudio del ciclo de vida del grupo predominante en un cultivo comercial de alstroemeria de Madrid - Cundinamarca

    Directory of Open Access Journals (Sweden)

    Martínez. John Wilson

    1994-06-01

    Full Text Available Slugs are an important pest due to the wide range of crops that they are able to attack. Lately, they have been registe red as an important pest in alstroemeria crop, where they leed with the tender buds arthe plant base, avoiding new productive stems development and causing yield decreases.
    Due to the lack of  knowledge about those molluscs and the high soil moisture and low light conditions into alstroemeria crop that enhance slugs development as a pest, this research was done. This work that was carried out in Jardines de
    Colombia Ltda (Madrid-Cundinamarca under laboratory and comercial greeenhouse conditions includes taxonomic determination and lile cycle study of the predominant slug group. Also, lour other groups that are present in the same crop were taxonomically determined. Results show that egg
    has an incubation time 01 17.17 days under laboratory and 21.7 days under greenhouse conditions. Slug lile cycle has a 124.5 and 123.9 days duration, respectively. Samples of each slug group sended to specialists, be long to Limacidae and Arionidae lamilies, and Deroceras and Limax genera were present in Limacidae lamily. Genera in Arionidae lamily weren't determined.Las babosas son una plaga importante debido a el amplio rango de cultivos que pueden llegar a atacar. Ultimamente, se han registrado como plaga importante en el cultivo de Alstroemeria en donde se alimentan de los brotes tiernos de la base de la planta, evitando el desarrollo de nuevos tallos
    productivos y, por consiguiente, originando disminución en el rendimiento. Debido a la falta de conocimiento sobre estos moluscos y a las condiciones de alta humedad y baja luminosidad dentro del cultivo de alstroemeria, que favorecen
    su desarrollo, se hizo indispensable la realización de la presente investigación. El trabajo fué realizado en la Empresa Jardines de Colombia Ltda (Madrid- Cundinamarca, tanto bajo condiciones de laboratorio, como de invernadero

  1. Challenges in Slug Modeling and Control for Offshore Oil and Gas Productions

    DEFF Research Database (Denmark)

    Pedersen, Simon; Løhndorf, Petar Durdevic; Yang, Zhenyu

    2017-01-01

    The upstream offshore multi-phase well-pipeline-riser installations are facing huge challenges related to slugging flow: An unstable flow regime where the flow rates, pressures and temperatures oscillate in the multi-phase pipelines. One typical severe slug is induced by vertical wells or risers...... causing the pressure to build up and hence originates the oscillating pressure and flow. There exist many negative consequences related to the severe slugging flow and thus lots of investments and effort have been put into reducing or completely eliminating the severe slug. This paper reviews in details...... the state-of-the-art related to analysis, detection, dynamical modeling and elimination of the slug within the offshore oil & gas Exploration and Production (E&P) processes. Modeling of slugging flow has been used to investigate the slug characteristics and for design of anti-slug control as well, however...

  2. A model for cell type localization in the migrating slug of ...

    Indian Academy of Sciences (India)

    PRAKASH

    . Localization of the three major cell types within the migrating slug stage is a dynamic process (Sternfeld 1992;. A model for cell type localization in the migrating slug of Dictyostelium discoideum based on differential chemotactic sensitivity to ...

  3. Estimation of gas and liquid slug lengths for T-shaped microreactors

    OpenAIRE

    Miyabayashi, K.; Tonomura, O.; Hasebe, S.

    2015-01-01

    Microreactors with gas–liquid slug flow have an advantage over the conventional batch reactors in mass transfer between mutually immiscible fluids because of the internal circulation flow within the liquid slug. To realize stable long-term operation of microreactors with gas–liquid slug flow, the slug lengths in the microreactors have to be monitored and controlled, because they influence mass transfer performance. In this study, an experimental investigation is carried out to analyze the for...

  4. Is a combination of different natural substances suitable for slug (Arion spp.) control?

    Energy Technology Data Exchange (ETDEWEB)

    Laznik, Ž.; Trdan, S.

    2016-11-01

    In a laboratory study we investigated the contact and barrier efficacy of different natural substances (wood ash, sawdust, hydrated lime, and diatomaceous earth) against slugs of the genus Arion, an important agricultural pest. Natural substances were tested individually and in combination with each other. The experiment was carried out in plastic petri dishes and in glass insectaria. Moistened tampons and fresh leaves of lettuce were placed into both experimental arenas. The slugs were starved for 48 hours prior to the experiment. Six categories of behaviour were identified for slugs in the presence of the natural substances: (1) slug survived the experiment, (2) slug died during the experiment, (3) slug crossed the barrier, (4) slug did not cross the barrier, (5) slug fed on the lettuce, and (6) slug did not feed on the lettuce. The effect of different treatments (natural substances) was significant. The results of our study have shown that hydrated lime had the best contact efficacy on slugs (the mortality of slugs was 100%), both individually and in combination with other substances. The treatments with hydrated lime also proved to be the most efficient barrier preventing slugs from feeding on lettuce. Hydrated lime shows great potential in Arion control in our investigation; however, further research is needed to investigate the practical value (how to avoid the problem when the substance becomes wet), safety and economics of hydrated lime used in this way. (Author)

  5. Is a combination of different natural substances suitable for slug (Arion spp. control?

    Directory of Open Access Journals (Sweden)

    Žiga Laznik

    2016-08-01

    Full Text Available In a laboratory study we investigated the contact and barrier efficacy of different natural substances (wood ash, sawdust, hydrated lime, and diatomaceous earth against slugs of the genus Arion, an important agricultural pest. Natural substances were tested individually and in combination with each other. The experiment was carried out in plastic petri dishes and in glass insectaria. Moistened tampons and fresh leaves of lettuce were placed into both experimental arenas. The slugs were starved for 48 hours prior to the experiment. Six categories of behaviour were identified for slugs in the presence of the natural substances: (1 slug survived the experiment, (2 slug died during the experiment, (3 slug crossed the barrier, (4 slug did not cross the barrier, (5 slug fed on the lettuce, and (6 slug did not feed on the lettuce. The effect of different treatments (natural substances was significant. The results of our study have shown that hydrated lime had the best contact efficacy on slugs (the mortality of slugs was 100%, both individually and in combination with other substances. The treatments with hydrated lime also proved to be the most efficient barrier preventing slugs from feeding on lettuce. Hydrated lime shows great potential in Arion control in our investigation; however, further research is needed to investigate the practical value (how to avoid the problem when the substance becomes wet, safety and economics of hydrated lime used in this way.

  6. Modelling Morphogenesis: From Single Cells to Crawling Slugs

    NARCIS (Netherlands)

    Savill, N.J.; Hogeweg, P.

    1996-01-01

    We present a three-dimensional hybrid cellular automata (CA)/partial differential equation (PDE) model that allows for the study of morphogenesis in simple cellular systems. We apply the model to the cellular slime mold Dictyostelium discoideum "from single cells to crawling slug". Using simple

  7. Modeling cross-hole slug tests in an unconfined aquifer

    CERN Document Server

    Malama, Bwalya; Brauchler, Ralf; Bayer, Peter

    2016-01-01

    A modified version of a published slug test model for unconfined aquifers is applied to cross-hole slug test data collected in field tests conducted at the Widen site in Switzerland. The model accounts for water-table effects using the linearised kinematic condition. The model also accounts for inertial effects in source and observation wells. The primary objective of this work is to demonstrate applicability of this semi-analytical model to multi-well and multi-level pneumatic slug tests. The pneumatic perturbation was applied at discrete intervals in a source well and monitored at discrete vertical intervals in observation wells. The source and observation well pairs were separated by distances of up to 4 m. The analysis yielded vertical profiles of hydraulic conductivity, specific storage, and specific yield at observation well locations. The hydraulic parameter estimates are compared to results from prior pumping and single-well slug tests conducted at the site, as well as to estimates from particle size ...

  8. [Investigations into the X-ray-influenced radula-replacement in the naked snail Limax flavus L.

    Science.gov (United States)

    Kerth, Klaus; Krause, Gerhard

    1969-03-01

    1. The naked snailLimax flavus L. has a radula with longitudinal rows of uniform teeth and cross-rows of teeth with a gradually changing form towards the radula's edge in regular succession, (Fig. 1). The individual tooth sits on the front part of a basal plate. This lies on the radula membrane (Fig. 2). 2. The radula is constantly shortened at its frontal end and is continuously renewed at the rear end of the radula gland. - This is an epidermal fold of the mouth cavity. At this place of radula-development lies a region of large secretion-cells, the odontoblasts. These are arranged together in groups (Fig. 10, 11 and 13). Each longitudinal toothrow with the underlying membrane, is produced by one group of odontoblasts. Each group for a lateral tooth in the medial region of the radula consists of 15 cells. During the substitution of the cross-row processes of developing teeth in the medial part get more and more ahead of those at the edge. 3. In an odontoblasts-group one finds division of labour. The front cells produce membrane material and the basal plate. The rear cells of the group produce the tooth. During the formation of the tooth the rear cells change their apical surface profile. The form of the tooth's upperside corresponds to the apical profile of cells at the beginning of secretion (Fig. 14a, 15a, b). The form of the tooth's furrow responds to that of the apical odontoblasts-profile at the end of secretion (Fig. 14b, 15c). The odontoblasts are exclusively responsible for the definitive shape of the tooth. 4. After a single whole-body X-irradiation of young snails (dosis-range: 8,050-130,000 R, Table 2) a characteristically changed pattern of teeth arises. A region of cross-rows, following each other closer than normal, extends across the radula (Fig. 4, 80,500 R). The condensation of cross-rows depends on the dosis (Fig. 8, broken-lined graph). Slides show an abnormal form and irregular position of teeth and their basal plate (comp. Fig. 2a, b and 17

  9. Experimental investigation of the effect of liquid viscosity on slug flow in small diameter bubble column

    Directory of Open Access Journals (Sweden)

    Azzopardi Barry John

    2012-04-01

    Full Text Available The effect of liquid viscosity on slug flow in a 50 mm diameter bubble column was investigated experimentally using air-silicone oil as operating fluid with silicone oil of viscosities 5, 100, 1000 and 5000 mPa.s. Data was collected using Electrical Capacitance Tomography (ECT, a non-intrusive advanced instrumentation measuring technique and the high Speed Video Camera, through which the slug parameters such as length of Taylor bubbles and liquid slug, void fraction in Taylor bubbles and liquid slug, slug frequency, film thickness and pressure gradient in the slug, were measured and analyzed. The analysis was done using the void fraction time series, probability density function and power spectral density plots. Superficial gas velocities of 0.02≤Ugs≤0.361 m/s were used in the experiment. It was also observed that as viscosity increases, slug frequency, structure velocity, length of liquid slug, void fraction in liquid slug and void fraction in Taylor bubbles decreases; while the length of Taylor bubble, film thickness and pressure gradient in the slug increases.

  10. Role of the Slug Transcription Factor in Chemically-Induced Skin Cancer

    Directory of Open Access Journals (Sweden)

    Kristine von Maltzan

    2016-02-01

    Full Text Available The Slug transcription factor plays an important role in ultraviolet radiation (UVR-induced skin carcinogenesis, particularly in the epithelial-mesenchymal transition (EMT occurring during tumor progression. In the present studies, we investigated the role of Slug in two-stage chemical skin carcinogenesis. Slug and the related transcription factor Snail were expressed at high levels in skin tumors induced by 7,12-dimethylbenz[α]anthracene application followed by 12-O-tetradecanoylphorbol-13-acetate (TPA treatment. TPA-induced transient elevation of Slug and Snail proteins in normal mouse epidermis and studies in Slug transgenic mice indicated that Slug modulates TPA-induced epidermal hyperplasia and cutaneous inflammation. Although Snail family factors have been linked to inflammation via interactions with the cyclooxygenase-2 (COX-2 pathway, a pathway that also plays an important role in skin carcinogenesis, transient TPA induction of Slug and Snail appeared unrelated to COX-2 expression. In cultured human keratinocytes, TPA induced Snail mRNA expression while suppressing Slug expression, and this differential regulation was due specifically to activation of the TPA receptor. These studies show that Slug and Snail exhibit similar patterns of expression during both UVR and chemical skin carcinogenesis, that Slug and Snail can be differentially regulated under some conditions and that in vitro findings may not recapitulate in vivo results.

  11. Slug expression enhances tumor formation in a noninvasive rectal cancer model.

    Science.gov (United States)

    Camp, E Ramsay; Findlay, Victoria J; Vaena, Silvia G; Walsh, Jarret; Lewin, David N; Turner, David P; Watson, Dennis K

    2011-09-01

    Epithelial-to-mesenchymal transition (EMT) is a series of molecular changes allowing epithelial cancer cells to acquire properties of mesenchymal cells: increased motility, invasion, and protection from apoptosis. Transcriptional regulators such as Slug mediate EMT, working in part to repress E-cadherin transcription. We report a novel, noninvasive in vivo rectal cancer model to explore the role of Slug in colorectal cancer (CRC) tumor development. For the generation of DLD-1 cells overexpressing Slug (Slug DLD-1), a Slug or empty (Empty DLD-1) pCMV-3Tag-1 (kanamycin-resistant) vector was used for transfection. Cells were evaluated for Slug and E-cadherin expression, and cell migration and invasion. For the in vivo study, colon cancer cells (parental DLD-1, Slug DLD-1, empty DLD-1, and HCT-116) were submucosally injected into the posterior rectum of nude mice using endoscopic guidance. After 28 d, tumors were harvested and tissue was analyzed. Slug expression in our panel of colon cancer cell lines was inversely correlated with E-cadherin expression and enhanced migration/invasion. Slug DLD-1 cells demonstrated a 21-fold increased Slug and 19-fold decreased E-cadherin expression compared with empty DLD-1. Similarly, the Slug DLD-1 cells had significantly enhanced cellular migration and invasion. In the orthotopic rectal cancer model, Slug DLD-1 cells formed rectal tumors in 9/10 (90%) of the mice (mean volume = 458 mm(3)) compared with only 1/10 (10%) with empty DLD-1 cells. Slug mediates EMT with enhanced in vivo rectal tumor formation. Our noninvasive in vivo model enables researchers to explore the molecular consequences of altered genes in a clinically relevant rectal cancer in an effort to develop novel therapeutic approaches for patients with rectal cancer. Published by Elsevier Inc.

  12. Analysis of Slug Tests in Formations of High Hydraulic Conductivity

    Science.gov (United States)

    Butler, J.J.; Garnett, E.J.; Healey, J.M.

    2003-01-01

    A new procedure is presented for the analysis of slug tests performed in partially penetrating wells in formations of high hydraulic conductivity. This approach is a simple, spreadsheet-based implementation of existing models that can be used for analysis of tests from confined or unconfined aquifers. Field examples of tests exhibiting oscillatory and nonoscillatory behavior are used to illustrate the procedure and to compare results with estimates obtained using alternative approaches. The procedure is considerably simpler than recently proposed methods for this hydrogeologic setting. Although the simplifications required by the approach can introduce error into hydraulic-conductivity estimates, this additional error becomes negligible when appropriate measures are taken in the field. These measures are summarized in a set of practical field guidelines for slug tests in highly permeable aquifers.

  13. A conservative fully implicit algorithm for predicting slug flows

    Science.gov (United States)

    Krasnopolsky, Boris I.; Lukyanov, Alexander A.

    2018-02-01

    An accurate and predictive modelling of slug flows is required by many industries (e.g., oil and gas, nuclear engineering, chemical engineering) to prevent undesired events potentially leading to serious environmental accidents. For example, the hydrodynamic and terrain-induced slugging leads to unwanted unsteady flow conditions. This demands the development of fast and robust numerical techniques for predicting slug flows. The presented in this paper study proposes a multi-fluid model and its implementation method accounting for phase appearance and disappearance. The numerical modelling of phase appearance and disappearance presents a complex numerical challenge for all multi-component and multi-fluid models. Numerical challenges arise from the singular systems of equations when some phases are absent and from the solution discontinuity when some phases appear or disappear. This paper provides a flexible and robust solution to these issues. A fully implicit formulation described in this work enables to efficiently solve governing fluid flow equations. The proposed numerical method provides a modelling capability of phase appearance and disappearance processes, which is based on switching procedure between various sets of governing equations. These sets of equations are constructed using information about the number of phases present in the computational domain. The proposed scheme does not require an explicit truncation of solutions leading to a conservative scheme for mass and linear momentum. A transient two-fluid model is used to verify and validate the proposed algorithm for conditions of hydrodynamic and terrain-induced slug flow regimes. The developed modelling capabilities allow to predict all the major features of the experimental data, and are in a good quantitative agreement with them.

  14. Comparison of air and water quenching of HDS slugs

    Energy Technology Data Exchange (ETDEWEB)

    Burk, J.A.

    1988-02-03

    This memorandum recommends the use of water quenching, rather than air quenching, for pressed slugs in any future project to substantially update the Building 313-M slug manufacturing facility. At the outset of the recently canceled Project S-4092, Improved Slug Processing Facility (ISPF), 313-M, consensus of the SRP liaison team was to replace the existing water quench facility with air quenching. Principal motivations were to eliminate a liquid waste stream, reduce the quantity of process water used, and attain a more reliable mechanical system. During the ensuing years, unforeseen difficulties with air quenching have been realized. Also, effective methods of reducing and treating the waste streams generated by water quenching have been developed. Both methods the author believes will work. However, the propriety of either method of quenching is a function of the system into which it is being incorporated. Each method carried with it a lot of concealed constraint s and carefully designed additional equipment. There is today a consensus that water quenching is preferable. For future reference, some advantages and disadvantages of the two quenching methods are discussed.

  15. SFRP2 and slug contribute to cellular resistance to apoptosis in hypertrophic scars.

    Directory of Open Access Journals (Sweden)

    Liang Chen

    Full Text Available Hypertrophic scars (HS are skin disorders which occur after wounding and thermal injury. Our previous studies have suggested that secreted frizzled-related protein 2 (SFRP2 is involved in HS formation and that the suppression of SFRP2 promotes apoptosis of hypertrophic scar fibroblasts (HSFBs. However, the mechanisms have not been clarified. Previous studies revealed that Slug expression inhibits cell apoptosis, in vitro and in vivo, and SFRP2 regulates the expression of Slug in cervical cancer cells. In the present study, we quantified differential expression levels of expression of SFRP2 and Slug in HS and normal skin tissues by immunohistochemistry, both of which have important anti-apoptosis roles. Furthermore, a short hairpin RNA approach was adopted to investigate the potential function of SFRP2 and Slug in HSFB apoptosis. Cell apoptosis was detected using fluorescence-activated cell sorting and Caspase-3 activity was assayed by spectrophotometry. This study demonstrates that SFRP2 expression, as well as Slug, is dramatically up-regulated in HS relative to normal skin tissues, and the Slug expression is positively correlated with SFRP2. Slug expression was down-regulated in SFRP2-deficient cells, and the down-regulation of Slug expression increased sensitivity to apoptosis which was induced through a caspase-3-dependent pathway. The infected cells with reduced levels of Slug were tested for the expression of apoptosis-related genes (Bcl-2, Bax and PUMA which were previously identified as Slug targets. Bcl-2 expression was down-regulated in Slug-deficient cells. In conclusion, SFRP2 appears to interact with Slug to affect the apoptosis of hypertrophic scar fibroblasts.

  16. An NF-?B and Slug Regulatory Loop Active in Early Vertebrate Mesoderm

    OpenAIRE

    Chi Zhang; Carl, Timothy F.; Evan D Trudeau; Thomas Simmet; Klymkowsky, Michael W.

    2006-01-01

    Background In both Drosophila and the mouse, the zinc finger transcription factor Snail is required for mesoderm formation; its vertebrate paralog Slug (Snai2) appears to be required for neural crest formation in the chick and the clawed frog Xenopus laevis. Both Slug and Snail act to induce epithelial to mesenchymal transition (EMT) and to suppress apoptosis. Methodology & Principle Findings Morpholino-based loss of function studies indicate that Slug is required for the normal expression of...

  17. Characteristics of slug flow in narrow rectangular channels under vertical condition

    Science.gov (United States)

    Wang, Yang; Yan, Changqi; Sun, Licheng; Xing, Dianchuan; Yan, Chaoxing; Tian, Daogui

    2013-07-01

    Gas-liquid slug flow is widely encountered in many practical industrial applications. A detailed understanding of the hydrodynamics of gas slug has important significance for modeling of the slug flow. Non-intrusive flow visualization using a high speed video camera system is applied to study characteristics of slug flow in a vertical narrow rectangular channel (3.25×40 mm2). Ideal Taylor bubbles are hardly observed, and most of the gas slugs are deformed, much more seriously at high liquid superficial velocity. The liquid film thicknesses of left and right narrow sides surrounding gas slug are divergent and wavy, but it has weak effect on liquid film velocity. The gas and liquid velocity as well as the length of gas slug have significant effect on the separating liquid film thickness. The separating liquid film velocity is decreased with the increase of gas superficial velocity at low liquid velocity, and increased with the increase of liquid superficial velocity. The film stops descending and the gas superficial velocity has no significant effect on liquid film separating velocity at high liquid velocity (jL≥1.204 m/s), and it is mainly determined by the liquid flow rate. The shape of slug nose has a significant effect on its velocity, while the effect of its length is very weak. The Ishii&Jones-Zuber drift flux correlation could predict slug velocity well, except at low liquid superficial velocity by reason of that the calculated drift velocity is less than experimental values.

  18. Three-dimensional numerical simulations of three-phase slug flows in horizontal pipes

    Science.gov (United States)

    Wang, Yan; Yang, Junfeng; Matar, Omar

    2015-11-01

    One of the most common flow regimes in pipelines is that of slug flow: slug bodies corresponding to alternating blocks of aerated liquid which bridge the pipe, separated by elongated bubbles; the latter ride atop a liquid layer. The slugs travel at velocities that exceed the mixture superficial velocity; this can potentially cause structural damage, particularly at pipe bends and junctions. Two-phase slug flows have received considerable attention in the literature both experimentally and computationally but there has been very little work carried out on three-phase slugging. In the present work, the evolution of oil-water-air three-phase slug flow in a horizontal cylindrical pipe is investigated using two-dimensional and three-dimensional computational fluid dynamics simulations. The parameters characterising three-phase slug flow, e.g. slug length, propagation velocity, and slug formation frequency, are determined for various gas and liquid superficial velocities for a given pipe geometry. The results of this work are compared to available experimental data and numerical solutions based on approximate, one-dimensional models relying on the use of empirical correlations. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  19. Slug overexpression induces stemness and promotes hepatocellular carcinoma cell invasion and metastasis.

    Science.gov (United States)

    Sun, Yu; Song, Guo-Dong; Sun, Ning; Chen, Jian-Qiu; Yang, Shao-Shi

    2014-06-01

    Detection of metastasis of hepatocellular carcinoma (HCC) is crucial for early diagnosis. Epithelial-mesenchymal transition (EMT) is a common event in the metastasis of tumor cells. Slug and Snail are homologous proteins, which play an important role in EMT. The present study aimed to investigate whether Slug and Snail overexpression is associated with the invasiveness of HCC in vitro and in vivo. Invasion, colony formation and wound healing assays, as well as flow cytometry analysis, were performed to examine the invasiveness and proliferation capabilities of HepG2 cells following transfection with cNDA or the siRNA of Slug or Snail. The effects of Slug on HCC in vivo were examined using a xenograft model. Slug upregulation increased the percentage of cluster of differentiation (CD)133+ cells among HepG2 cells, and induced cell invasion and proliferation; whereas Snail upregulation did not affect the cells in vitro. The Slug overexpression group exhibited the highest rate of tumor growth compared with the Snail overexpression and control groups in vivo. These findings demonstrated that Slug increases the percentage of CD133+ cells, promotes the clonigenicity of HCC cells and induces a stronger stemness in Slug-overexpressing cells. These changes activate dormant developmental pathways in invading tumor cells. Thus, Slug may serve as a novel target for HCC prognosis and therapy.

  20. Slug Is Associated With Tumor Metastasis and Angiogenesis in Ovarian Cancer.

    Science.gov (United States)

    Gu, Anxin; Jie, Yamin; Yao, Qiang; Zhang, Yuqi; Mingyan, E

    2017-02-01

    Ovarian cancer is the most lethal gynecologic malignancy among women and usually initiated by the malignant transformation of epithelial cells. The progression of ovarian cancer involves a cascade of events, including tumor cell epithelial-mesenchymal transition (EMT), invasion, migration, and angiogenesis. Slug plays vital roles in the development of motile and invasive manner of cancer cells via EMT progression. The present work is devoted to investigate the effect of slug on the invasion and angiogenesis in ovarian cancer. The findings reveal that tumors with high expression of slug (44 of 60) represent higher tumor grade, lymph node metastasis, and worse prognosis than those with low expression (16 of 60; P slug and the microvessel density (MVD). Results of transwell migration assay showed that decreased slug induced by short hairpin RNA contributed to the repressed invasion and migration of SKOV3 cells. Additionally, the migration and tube formation capacity of human umbilical vein endothelial cells were markedly decreased in SKOV3-sh-conditioned medium compared to SKOV3 and SKOV3-NC. Furthermore, xenograft mouse models (SKOV3/SKOV3-sh cells injection into BALB/c nude mice) were developed to validate the effects of slug. The data confirmed that inhibited expression of slug extensively decreased the growth of tumor and MVD in vivo. Moreover, knockdown of slug can significantly reduce tumor angiogenesis of SKOV3 cells via ccn1/vascular endothelial growth factor. Thus, our present study demonstrates that slug is closely associated with tumor metastasis and angiogenesis in ovarian cancer.

  1. A Probabilistic Approach for Predicting Average Slug Frequency in Horizontal Gas/Liquid Pipe Flow

    Directory of Open Access Journals (Sweden)

    Kadri U.

    2013-02-01

    Full Text Available In this paper, we present a model for predicting the average slug frequency in horizontal gas/liquid pipe flow. The model considers the probability of slug formation if slugs are triggered at the antinodes of a sinusoidal perturbation, along the pipe at the frequency of oscillation of the interface. A slug is assumed to form if and only if triggered at a space-time far enough from existing slugs. The probability of forming slugs is found to decrease with distance from the inlet, since the downstream passage of existing slugs prevents the formation of new slugs. Predictions by the model are compared with air/water, freon/water and air/oil measurements found in literature, with a satisfactory agreement. However, a deviation from measurements is observed when considering high viscosity liquid. The model contributes to the prediction of slug flow regime and can act as a guideline toward the design of gas/liquid horizontal pipe flow.

  2. POSSIBILITIES OF ENVIRONMENTALLY ACCEPTABLE CONTROL METHODS AGAINST ECONOMICALLY IMPORTANT SLUGS WITH EMPHASIS ON THE RESULTS OF DOMESTIC RESEARCHES OF CONTROLLING ARIONIDAE SLUGS

    Directory of Open Access Journals (Sweden)

    Žiga Laznik

    2016-10-01

    Full Text Available Slugs from the Arionidae and Limacidae families are classified as an important economic agricultural pests. They are omnivorous animals. Slugs are sensitive to drying out, so they are active at night and in cloudy, rainy weather. They cause economic damage to the vegetables, crops, fruit trees, shrubs, grasses, herbs and ornamental plants. First reports of slugs control are dating from the early 20th century. This was followed by an important discovery in the year 1934 when in South Africa metaldehyde was discovered. This discovery has brought significant progress in the protection of plants against slugs. The next major step in the development of molluscicides was achieved with the discovery of carbamates. Due to the proven non-target effect of metaldehyde and other substances with molluscicidal activity researchers are looking for alternative solutions in the protection of plants against slugs. In this paper we present a variety of environmentally acceptable methods of slugs control, such as proper soil cultivation, beer trapping, barriers and the use of so-called electrical fences against slugs.

  3. The E-cadherin repressor slug and progression of human extrahepatic hilar cholangiocarcinoma

    Directory of Open Access Journals (Sweden)

    Wang Xin-sheng

    2010-07-01

    Full Text Available Abstract Objectives This study explored the expression and function of Slug in human extrahepatic hilar cholangiocarcinoma (EHC to identify its role in tumor progression. Methods The expression of Snail and Slug mRNA in 52 human tissue samples of EHC was investigated. The mRNA of Snail and Slug were quantified using reverse transcriptase-PCR, and correlations with E-cadherin expression and clinicopathological factors were investigated. We then investigated transfection of Slug cDNA in endogenous E-cadherin-positive human EHC FRH0201 cells, selectively induced the loss of E-cadherin protein expression, and then small interfering RNA (siRNA for inhibition of Slug expression in endogenous Slug-positive human EHC QBC939 cells, selectively induced the loss of Slug protein expression. A Boyden chamber transwell assay was used for invasion. Results Slug mRNA was overexpressed in 18 cases (34.6% of EHC compared with adjacent noncancerous tissue. E-Cadherin protein expression determined in the same 52 cases by immunohistochemistry was significantly down-regulated in those cases with Slug mRNA overexpression (P = 0.0001. The tumor and nontumor ratio of Slug mRNA was correlated with nodal metastasis(p = 0.0102, distant metastasis (p = 0.0001and Survival time(p = 0.0443. However, Snail mRNA correlated with neither E-cadherin expression nor tumor invasiveness. By inhibiting Slug expression by RNA interference, we found that reduced Slug levels upregulated E-cadherin and decreased invasion in QBC939 cell. When the QBC939 cells was infected with Slug cDNA,, significant E-cadherin was downregulated and increased invasion in QBC939 cell. Conclusions The results suggested that Slug expression plays an important role in both the regulation of E-cadherin expression and in the acquisition of invasive potential in human EHC. Slug is possibly a potential target for an antitumor therapy blocking the functions of invasion and metastasis in human EHCs.

  4. A biography of an invasive terrestrial slug: the spread, distribution and habitat of Deroceras invadens

    Directory of Open Access Journals (Sweden)

    John Hutchinson

    2014-09-01

    Full Text Available The article reviews distribution records of Deroceras invadens (previously called D. panormitanum and D. caruanae, adding significant unpublished records from the authors’ own collecting, museum samples, and interceptions on goods arriving in the U.S.A. By 1940 D. invadens had already arrived in Britain, Denmark, California, Australia and probably New Zealand; it has turned up in many further places since, including remote oceanic islands, but scarcely around the eastern Mediterranean (Egypt and Crete are the exceptions, nor in Asia. Throughout much of the Americas its presence seems to have been previously overlooked, probably often being mistaken for D. laeve. New national records include Mexico, Costa Rica, and Ecuador, with evidence from interceptions of its presence in Panama, Peru, and Kenya. The range appears limited by cold winters and dry summers; this would explain why its intrusion into eastern Europe and southern Spain has been rather slow and incomplete. At a finer geographic scale, the occurrence of the congener D. reticulatum provides a convenient comparison to control for sampling effort; D. invadens is often about half as frequently encountered and sometimes predominates. Deroceras invadens is most commonly found in synanthropic habitats, particularly gardens and under rubbish, but also in greenhouses, and sometimes arable land and pasture. It may spread into natural habitats, as in Britain, South Africa, Australia and Tenerife. Many identifications have been checked in the light of recent taxonomic revision, revealing that the sibling species D. panormitanum s.s. has spread much less extensively. A number of published or online records, especially in Australia, have turned out to be misidentifications of D. laeve.

  5. Ringiculid bubble snails recovered as the sister group to sea slugs (Nudipleura)

    Science.gov (United States)

    Kano, Yasunori; Brenzinger, Bastian; Nützel, Alexander; Wilson, Nerida G.; Schrödl, Michael

    2016-08-01

    Euthyneuran gastropods represent one of the most diverse lineages in Mollusca (with over 30,000 species), play significant ecological roles in aquatic and terrestrial environments and affect many aspects of human life. However, our understanding of their evolutionary relationships remains incomplete due to missing data for key phylogenetic lineages. The present study integrates such a neglected, ancient snail family Ringiculidae into a molecular systematics of Euthyneura for the first time, and is supplemented by the first microanatomical data. Surprisingly, both molecular and morphological features present compelling evidence for the common ancestry of ringiculid snails with the highly dissimilar Nudipleura—the most species-rich and well-known taxon of sea slugs (nudibranchs and pleurobranchoids). A new taxon name Ringipleura is proposed here for these long-lost sisters, as one of three major euthyneuran clades with late Palaeozoic origins, along with Acteonacea (Acteonoidea + Rissoelloidea) and Tectipleura (Euopisthobranchia + Panpulmonata). The early Euthyneura are suggested to be at least temporary burrowers with a characteristic ‘bubble’ shell, hypertrophied foot and headshield as exemplified by many extant subtaxa with an infaunal mode of life, while the expansion of the mantle might have triggered the explosive Mesozoic radiation of the clade into diverse ecological niches.

  6. Long liquid slugs in stratified gas/liquid flow in horizontal and slightly inclined pipes

    NARCIS (Netherlands)

    Kadri, U.

    2009-01-01

    Long liquid slugs reaching several hundreds pipe diameter may appear when transporting gas and liquid in horizontal and near horizontal pipes. The long slugs cause system vibration and separation difficulties that may lead to operational failures. Identifying and predicting the time and length

  7. The SIRT2 Deacetylase Stabilizes Slug to Control Malignancy of Basal-like Breast Cancer

    Directory of Open Access Journals (Sweden)

    Wenhui Zhou

    2016-10-01

    Full Text Available Overabundance of Slug protein is common in human cancer and represents an important determinant underlying the aggressiveness of basal-like breast cancer (BLBC. Despite its importance, this transcription factor is rarely mutated in BLBC, and the mechanism of its deregulation in cancer remains unknown. Here, we report that Slug undergoes acetylation-dependent protein degradation and identify the deacetylase SIRT2 as a key mediator of this post-translational mechanism. SIRT2 inhibition rapidly destabilizes Slug, whereas SIRT2 overexpression extends Slug stability. We show that SIRT2 deacetylates Slug protein at lysine residue K116 to prevent Slug degradation. Interestingly, SIRT2 is frequently amplified and highly expressed in BLBC. Genetic depletion and pharmacological inactivation of SIRT2 in BLBC cells reverse Slug stabilization, cause the loss of clinically relevant pathological features of BLBC, and inhibit tumor growth. Our results suggest that targeting SIRT2 may be a rational strategy for diminishing Slug abundance and its associated malignant traits in BLBC.

  8. Experimental investigation of terrain slugging: formation mechanism and potential mitigation methods

    NARCIS (Netherlands)

    Schiferli, W.; Hansen, J.H.; Brasjen, B.J.; Belfroid, S.P.C.

    2013-01-01

    An experimental study on terrain-induced slugging on shallow inclines (typically less than 3°) has been conducted, using three setups with a pipe diameter of around 1”, with incline lengths of 1 m, 3 m and 24 m. In addition to an extensive characterization of the formation and evolution of slugs as

  9. Transformation of a Water Slug in Free Fall Under the Conditions of Exposure to an Air Flow Orthogonal to the Direction of the Slug Motion

    Science.gov (United States)

    Volkov, R. S.; Zabelin, M. V.; Kuznetsov, G. V.; Strizhak, P. A.

    2016-07-01

    An experimental study has been made of the influence of an orthogonal (side) air flow propagating with a velocity to 5 m/s on the phases of transformation of a water slug with an initial volume of 0.05-0.5 liter in free fall from a height of 3 m. Use was made of Phantom V411 and Phantom Miro M310 high-speed video cameras and a Tema Automotive software system with the function of continuous tracking. The laws of retardation of the phases of transformation of the water slug from the instant of formation to that of formation of a droplet cloud under the action of the air flow orthogonal to the direction of the slug motion, and also of the deceleration, removal, and destruction of the droplets and fragments of water separating from the slug surface, have been established.

  10. An analytical model for gas overpressure in slug-driven explosions: Insights into Strombolian volcanic eruptions

    Science.gov (United States)

    Del Bello, Elisabetta; Llewellin, Edward W.; Taddeucci, Jacopo; Scarlato, Piergiorgio; Lane, Steve J.

    2012-02-01

    Strombolian eruptions, common at basaltic volcanoes, are mildly explosive events that are driven by a large bubble of magmatic gas (a slug) rising up the conduit and bursting at the surface. Gas overpressure within the bursting slug governs explosion dynamics and vigor and is the main factor controlling associated acoustic and seismic signals. We present a theoretical investigation of slug overpressure based on magma-static and geometric considerations and develop a set of equations that can be used to calculate the overpressure in a slug when it bursts, slug length at burst, and the depth at which the burst process begins. We find that burst overpressure is controlled by two dimensionless parameters: V', which represents the amount of gas in the slug, and A', which represents the thickness of the film of magma that falls around the rising slug. Burst overpressure increases nonlinearly as V' and A' increase. We consider two eruptive scenarios: (1) the "standard model," in which magma remains confined to the vent during slug expansion, and (2) the "overflow model," in which slug expansion is associated with lava effusion, as occasionally observed in the field. We find that slug overpressure is higher for the overflow model by a factor of 1.2-2.4. Applying our model to typical Strombolian eruptions at Stromboli, we find that the transition from passive degassing to explosive bursting occurs for slugs with volume >24-230 m3, depending on magma viscosity and conduit diameter, and that at burst, a typical Strombolian slug (with a volume of 100-1000 m3) has an internal gas pressure of 1-5 bars and a length of 13-120 m. We compare model predictions with field data from Stromboli for low-energy "puffers," mildly explosive Strombolian eruptions, and the violently explosive 5 April 2003 paroxysm. We find that model predictions are consistent with field observations across this broad spectrum of eruptive styles, suggesting a common slug-driven mechanism; we propose that

  11. Relationships Between Aphids (Insecta: Homoptera: Aphididae) and Slugs (Gastropoda: Stylommatophora: Agriolimacidae) Pests of Legumes (Fabaceae: Lupinus).

    Science.gov (United States)

    Kozłowski, Jan; Strażyński, Przemysław; Jaskulska, Monika; Kozłowska, Maria

    2016-01-01

    Lupin plants are frequently damaged by various herbivorous invertebrates. Significant among these are slugs and aphids, which sometimes attack the same plants. Relationships between aphids, slugs and food plant are very interesting. Grazing by these pests on young plants can lead to significant yield losses. There is evidence that the alkaloids present in some lupin plants may reduce grazing by slugs, aphids and other invertebrates. In laboratory study was analyzed the relationships between aphid Aphis craccivora and slug Deroceras reticulatum pests of legumes Lupinus angustifolius. It was found that the presence of aphids significantly reduced slug grazing on the plants. The lupin cultivars with high alkaloid content were found to be less heavily damaged by D. reticulatum, and the development of A. craccivora was found to be inhibited on such plants. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

  12. Plant-Wide Anti-Slug Control for Offshore Oil and Gas Processes

    DEFF Research Database (Denmark)

    Pedersen, Simon

    measurements give better results than the frequently used riser topside pressure (Pt). A supervisory self-learning control strategy is developed and the results show that the decision making based on the supervisor drives the system close to the closed-loop bifurcation point, but a faster control scheme can......In offshore Oil & Gas production processes the undesired severe slug flow regime can be present. The negative impact of severe slug is crucial to the production rate and process safety. In this work, the severe slugs which occur in the well-pipeline-riser system are experimentally and theoretically...... reduce the settling time significantly. A number of anti-slug control strategies are proposed, where the robust control solution shows the best potential in both anti-slug control and production rate improvement. Simulation results show that control solutions with the riser bottom pressure Pb performs...

  13. Measurements of interfacial film thickness for immiscible liquid liquid slug/droplet flows

    Science.gov (United States)

    Qiu, Huihe; Wang, Xishi; Hong, Fangjun

    2005-06-01

    A novel method for measuring the interfacial liquid film thickness between immiscible liquids of a slug/droplet in a micropipe is proposed. This method is capable of measuring an oil slug/droplet in water with the relative refractive index (m) between the immiscible liquids very close to one in a capillary tube. Unlike the measurement configuration for an air slug in water, an optical oriental for optimizing the refracted fringes pattern by the liquid-liquid interface is introduced. Measurements of film thicknesses of a kerosene oil droplet/slug in a water wetted capillary tube (m > 1) and a water droplet/slug in a kerosene oil wetted capillary tube (m diagnostic method is easy to implement and it will have great potential for immiscible liquid flow research in microfluidic channels.

  14. Influence of the initial conditions for the numerical simulation of two-phase slug flow

    Energy Technology Data Exchange (ETDEWEB)

    Pachas Napa, Alex A.; Morales, Rigoberto E.M.; Medina, Cesar D. Perea

    2010-07-01

    Multiphase flows in pipelines commonly show several patterns depending on the flow rate, geometry and physical properties of the phases. In oil production, the slug flow pattern is the most common among the others. This flow pattern is characterized by an intermittent succession in space and time of an aerated liquid slug and an elongated gas bubble with a liquid film. Slug flow is studied through the slug tracking model described as one-dimensional and Lagrangian frame referenced. In the model, the mass and the momentum balance equations are applied in control volumes constituted by the gas bubble and the liquid slug. Initial conditions must be determined, which need to reproduce the intermittence of the flow pattern. These initial conditions are given by a sequence of flow properties for each unit cell. Properties of the unit cell in initial conditions should reflect the intermittence, for which they can be analyzed in statistical terms. Therefore, statistical distributions should be obtained for the slug flow variables. Distributions are complemented with the mass balance and the bubble design model. The objective of the present work is to obtain initial conditions for the slug tracking model that reproduce a better adjustment of the fluctuating properties for different pipe inclinations (horizontal, vertical or inclined). The numerical results are compared with experimental data obtained by PFG/FEM/UNICAMP for air-water flow at 0 deg, 45 deg and 90 deg and good agreement is observed. (author)

  15. Molecular analysis of predation by carabid beetles (Carabidae) on the invasive Iberian slug Arion lusitanicus.

    Science.gov (United States)

    Hatteland, B A; Symondson, W O C; King, R A; Skage, M; Schander, C; Solhøy, T

    2011-12-01

    The invasive Iberian slug, Arion lusitanicus, is spreading through Europe and poses a major threat to horticulture and agriculture. Natural enemies, capable of killing A. lusitanicus, may be important to our understanding of its population dynamics in recently invaded regions. We used polymerase chain reaction (PCR) to study predation on A. lusitanicus by carabid beetles in the field. A first multiplex PCR was developed, incorporating species-specific primers, and optimised in order to amplify parts of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of large Arion slugs, including A. lusitanicus from the gut contents of the predators. A second multiplex PCR, targeting 12S rRNA mtDNA, detected predation on smaller Arion species and the field slug Deroceras reticulatum. Feeding trials were conducted to measure the effects of digestion time on amplicon detectability. The median detection times (the time at which 50% of samples tested positive) for A. lusitanicus and D. reticulatum DNA in the foreguts of Carabus nemoralis were 22 h and 20 h, respectively. Beetle activity-densities were monitored using pitfall traps, and slug densities were estimated using quadrats. Predation rates on slugs in the field by C. nemoralis in spring ranged from 16-39% (beetles positive for slug DNA) and were density dependent, with numbers of beetles testing positive being positively correlated with densities of the respective slug species. Carabus nemoralis was shown to be a potentially important predator of the alien A. lusitanicus in spring and may contribute to conservation biological control.

  16. Spatiotemporal analysis of predation by carabid beetles (Carabidae on nematode infected and uninfected slugs in the field.

    Directory of Open Access Journals (Sweden)

    Bjørn Arild Hatteland

    Full Text Available The dynamics of predation on parasites within prey has received relatively little attention despite the profound effects this is likely to have on both prey and parasite numbers and hence on biological control programmes where parasites are employed. The nematode Phasmarhabditis hermaphrodita is a commercially available biological agent against slugs. Predation on these slugs may, at the same time, result in intraguild predation on slug-parasitic nematodes. This study describes, for the first time, predation by carabid beetles on slugs and their nematode parasites on both spatial and temporal scales, using PCR-based methods. The highest nematode infection levels were found in the slugs Deroceras reticulatum and Arion silvaticus. Numbers of infected slugs decreased over time and no infected slugs were found four months after nematode application. The density of the most abundant slug, the invasive Arion vulgaris, was positively related to the activity-density of the carabid beetle, Carabus nemoralis. Predation on slugs was density and size related, with highest predation levels also on A. vulgaris. Predation on A. vulgaris decreased significantly in summer when these slugs were larger than one gram. Predation by C. nemoralis on slugs was opportunistic, without any preferences for specific species. Intraguild predation on the nematodes was low, suggesting that carabid beetles such as C. nemoralis probably do not have a significant impact on the success of biological control using P. hermaphrodita.

  17. Spatiotemporal analysis of predation by carabid beetles (Carabidae) on nematode infected and uninfected slugs in the field.

    Science.gov (United States)

    Hatteland, Bjørn Arild; Haukeland, Solveig; Roth, Steffen; Brurberg, May Bente; Vaughan, Ian P; Symondson, William O C

    2013-01-01

    The dynamics of predation on parasites within prey has received relatively little attention despite the profound effects this is likely to have on both prey and parasite numbers and hence on biological control programmes where parasites are employed. The nematode Phasmarhabditis hermaphrodita is a commercially available biological agent against slugs. Predation on these slugs may, at the same time, result in intraguild predation on slug-parasitic nematodes. This study describes, for the first time, predation by carabid beetles on slugs and their nematode parasites on both spatial and temporal scales, using PCR-based methods. The highest nematode infection levels were found in the slugs Deroceras reticulatum and Arion silvaticus. Numbers of infected slugs decreased over time and no infected slugs were found four months after nematode application. The density of the most abundant slug, the invasive Arion vulgaris, was positively related to the activity-density of the carabid beetle, Carabus nemoralis. Predation on slugs was density and size related, with highest predation levels also on A. vulgaris. Predation on A. vulgaris decreased significantly in summer when these slugs were larger than one gram. Predation by C. nemoralis on slugs was opportunistic, without any preferences for specific species. Intraguild predation on the nematodes was low, suggesting that carabid beetles such as C. nemoralis probably do not have a significant impact on the success of biological control using P. hermaphrodita.

  18. Snails and slugs damaging the cut foliage, Cordyline fruticosa and use of biorationals towards their management.

    Science.gov (United States)

    Karthiga, S; Jegathambigai, V; Karunarathne, M D S D; Svinningen, A; Mikunthan, G

    2012-01-01

    Snails and slugs became a serious molluscan pests and damaging leaves of purple compacta, Cordyline fruticosa extensively grown for export at Green Farm Ltd, Sri Lanka. The export quality of leaves of C. fruticosa is lowered due to feeding of snails, Achantina fulica (Bowditch), Opeas pyrgula Schmacker and Boettgerx and Helix aspersa Muller and slugs incurring great loss to cut foliage industry. Paucity of information is available to understand snails and slugs damage and their host range that limits to develop suitable management practices. Therefore this study was aimed to determine damage, alternate hosts and to develop possible management practices. Snails and slugs damaged mainly fresh leaves of C. fruticosa. The severity of damage was 44.5% in infested field based on the visual rating method. Leaves of cassava, sting bean, okra, cucumber, passion fruit, papaya, Glyricidia and shoe flower were identified as alternate hosts and neem, Ixora and Dracaena spp were not served as alternate hosts. Among the plant materials tested for their repellence against snails and slugs revealed that neem seed powder was an irritant; neem leaves, mint leaves and Lantana leaves were acted as anti-feedant and Salt as chemical repellent. Among the barrier and bait experiments Bordeaux mixture exhibited a significant barrier effect against horizontal movement of snails. Baits made out of Metaldehyde bait, vegetables bait and jaggery had a strong effect in repelling the snails and slugs. Mulching with Madhuca longifolia punnac was the best to reduce the snails and slugs population compared to M. longifolia seed kernel powder. Oil from M. longifolia failed to reduce their population. Hence the results revealed that saponin containing M. longifolia punnac helped to eliminate snails and slugs when used as mulch. Metaldehyde, vegetable and jaggery baits are also useful to minimize their colonization further. Hence combination of these methods will help to prevent snails and slugs from

  19. Online slug detection in multi-phase transportation pipelines using electrical tomography

    DEFF Research Database (Denmark)

    Pedersen, Simon; Mai, Christian; Hansen, Leif

    2015-01-01

    Slugging flow in offshore oil & gas multi-phase transportation pipelines cause big challenges as the flow regime induces flow and pressure oscillations in the multi-phase pipelines. The negative impacts of the most severe slugs are significant and thus the elimination of slugging flow......) has been examined as an alternative to the traditional pressure transmitters. A lab-scaled testing facility has been constructed in order to obtain test data from a ERT transmitter with 12 probes. Different flow regimes have been generated by a pump and a compressor where 2-phase flow can be tested...

  20. Experimental Study of Stable Surfaces for Anti-Slug Control in Multi-phase Flow

    DEFF Research Database (Denmark)

    Pedersen, Simon; Løhndorf, Petar Durdevic; Stampe, Kasper

    2016-01-01

    Severe slugging flow is always challenging in oil & gas production, especially for the current offshore based production. The slugging flow can cause a lot of problems, such as those relevant to production safety, fatigue as well as capability. As one typical phenomenon in multi-phase flow dynamics...... with severe slugging flows. These correlations are reflected through an obtained stable surface in the parameter space, which is a natural extension of the bifurcation plot. The maximal production opportunity without compromising the stability is also studied. Relevant studies have already showed...

  1. Online Slug Detection in Multi-phase Transportation Pipelines Using Electrical Tomography

    DEFF Research Database (Denmark)

    Pedersen, Simon; Mai, Christian; Hansen, Leif

    2015-01-01

    Slugging flow in offshore oil & gas multi-phase transportation pipelines cause big challenges as the flow regime induces flow and pressure oscillations in the multi-phase pipelines. The negative impacts of the most severe slugs are significant and thus the elimination of slugging flow......) has been examined as an alternative to the traditional pressure transmitters. A lab-scaled testing facility has been constructed in order to obtain test data from a ERT transmitter with 12 probes. Different flow regimes have been generated by a pump and a compressor where 2-phase flow can be tested...

  2. A revised correlation based on heat transfer model of slug flow in mini/micro-channels

    Science.gov (United States)

    Li, Xuejiao; Jia, Li; Yin, Liaofei; An, Zhoujian

    2017-07-01

    As flow boiling in mini/micro-channel, slug flow was corresponding to the optimal heat transfer ability owing to the evaporation of thin liquid film. Based on the heat transfer mechanism of liquid film evaporation, a simplified heat transfer model of slug flow was proposed. Li-Wu heat transfer correlation (Int J Heat Mass Transf 53(9): 1778-1787, 2010) was revised by introducing evaporation parameter, C e . With the evaporation parameter, C e , the revised correlation predicted the slug flow database with MAE (Mean Absolute Error) 25.14%, which improved the prediction accuracy remarkably.

  3. Parameter studies to determine sensitivity of slug impact loads to properties of core surrounding structures

    Energy Technology Data Exchange (ETDEWEB)

    Gvildys, J.

    1985-01-01

    A sensitivity study of the HCDA slug impact response of fast reactor primary containment to properties of core surrounding structures was performed. Parameters such as the strength of the radial shield material, mass, void, and compressibility properties of the gas plenum material, mass of core material, and mass and compressibility properties of the coolant were used as variables to determine the magnitude of the slug impact loads. The response of the reactor primary containment and the partition of energy were also given. A study was also performed using water as coolant to study the difference in slug impact loads.

  4. Experimental Study of Stable Surfaces for Anti-Slug Control in Multi-phase Flow

    DEFF Research Database (Denmark)

    Pedersen, Simon; Løhndorf, Petar Durdevic; Yang, Zhenyu

    2014-01-01

    The severe slugging flow is always challenging in oil & gas production, especially for the current offshore based production. The slugging flow can cause a lot of potential problems, such as those relevant to production safety, fatigue as well as capability. As one typical phenomenon in multi-phase...... flow dynamics, the slug can be avoided or eliminated by proper facility design and control of operational conditions. Based on a testing facility which can emulate a pipeline-riser or a gas-lifted production well in a scaled-down manner, this paper experimentally studies the correlations of key...... operational parameters with severe slugging flows. These correlations are reflected through an obtained stable surface in the parameter space, which is a natural extension of the bifurcation plot. The maximal production opportunity without compromising the stability is also studied. Relevant studies have...

  5. Model for Terrain-Induced Slug Flow for High Viscous Liquids

    Directory of Open Access Journals (Sweden)

    Andrea Shmueli

    2014-12-01

    Full Text Available This paper presents the development and results of a simplified multiphase model for terrain-induced slugging analysis considering the viscosity effect of the liquid phase in the conservation equations. The phenomenon has been successfully modelled with numerical models (Fabre et al. 1990, Sarica et al 1991 that neglect the liquid viscosity effect. The objective of the present study is to clarify its importance in the numerical prediction of the characteristics of severe slugging. The results of the model where compared with experimental data reported in the literature showing a maximum percentage difference of 6% which represents a 7% improvement with respect to the prediction of existing models. The liquid viscosity has an effect on the duration of the severe slugging cycle. The cycle will reduce while the viscosity increases. Additionally, the effect of the riser inclination angle is analyzed showing a mitigation of the severe slugging phenomenon while decreasing the angle

  6. Review of Slug Detection, Modeling and Control Techniques for Offshore Oil & Gas Production Processes

    DEFF Research Database (Denmark)

    Pedersen, Simon; Løhndorf, Petar Durdevic; Yang, Zhenyu

    2015-01-01

    The current offshore oil & gas multi-phase production and transportation installations have big challenges related with the slugging flow: An unstable multi-phase flow regime where the flow rates, pressures and temperatures oscillate in the considered processes. Slug can be caused by different...... of these methods can simultaneously reduce the oil & gas production, which is a very big concern as the production rate is the key evaluation parameter for offshore production. We conclude that the slugging flow is a well-defined phenomenon, even though this subject has been extensively investigated in the past...... operating conditions and installation structures. The most severe slugs are often induced in long vertical risers or production wells, where liquid blocks gas at the riser/well base and correspondingly it causes the pressure to accumulate and hence originates the oscillating performance. There are many...

  7. Short interfering RNA directed against Slug blocks tumor growth, metastasis formation, and vascular leakage in bladder cancer.

    Science.gov (United States)

    Wang, Xinsheng; Zhang, Kejun; Sun, Lijiang; Liu, Jianqiang; Lu, Haipin

    2011-12-01

    In a previous study, we have identified Slug as selectively overexpressed in the highly invasive bladder cancer cells. Furthermore, Slug overexpression was correlated with metastasis in bladder cancer tissues. Here, we investigated the role and underlying mechanism of Slug in the process of growth, invasion and metastasis formation, and vascular leakage in a bladder cancer cell line T24. We knocked down in a bladder cancer cell line T24 by Slug siRNA, and the effects on invasion, metastasis, and proliferation were evaluated in vitro. A pseudometastatic model of bladder cancer in severe combined immunodeficient mice was used to assess the effects of Slug silencing on metastasis and angiogenesis development. Slug-specific siRNA in T24 cells led to a significant decrease in invasiveness and metastasis, proliferation rates, and angiogenesis in vitro. Slug-specific siRNA induced strong changes in cell invasiveness mainly through a mechanism of up-regulation of epithelial markers E-cadherin expression. Interestingly, E-cadherin-specific siRNA attenuated Slug siRNA-induced Matrigel invasion. Moreover, Slug-specific siRNA induced strong changes in microvessel counts in angiogenesis mainly through decreased activity of MMP-2, but not through cadherin expression and decreased activity of MMP-9. Restoration of MMP-2 expression in the Slug-silenced T24 cells resulted in an increased cell angiogenesis. Moreover, Slug-specific siRNA significantly reduced tumor growth by approximately 60% and inhibited metastasis and angiogenesis in a xenograft mouse model. This was accompanied by an increased expression of E-cadherin and a decreased expression of MMP-2 in tumor tissues. These data suggest that Slug regulates tumor growth, invasion and metastasis, and angiogenesis through E-cadherrin and MMPS passway. Blocking Slug signaling in bladder cancer may represent a novel strategy in the future to reduce metastatic disease burden in bladder cancer patients.

  8. INTERRELATION OF RHOMBICITY AND OCCURRENCE OF INTERNAL CRACKS AT CONTINUOUS CASTING OF SORTED SLUG

    Directory of Open Access Journals (Sweden)

    Ju. A. Samojlovich

    2008-01-01

    Full Text Available Analysis of deformations and stresses in cross section of sorted uninterruptedly-casted slugs at their solidification and cooling within limits of crystallizer with the aim of determination of possibilities for occurrence of internal cracks of diagonal type is carried out on basis of mathematical modeling, the peculiarities of the slug skin cooling at its shrinkage and separation from crystallizer wall are revealed.

  9. Searching the Human Genome for Snail and Slug With DNA@Home

    OpenAIRE

    Zarns, Kristopher; Desell, Travis; Nechaev, Sergei; Dhasarathy, Archana

    2015-01-01

    DNA@Home is a volunteer computing project that aims to use Gibbs Sampling for the identification and location of DNA control signals on full genome-scale datasets. A fault tolerant and asynchronous implementation of Gibbs sampling using the Berkeley Open Infrastructure for Network Computing (BOINC) was used to identify the location of binding sites of the SNAI1 (Snail) and SNAI2 (Slug) transcription factors across the human genome. Genes regulated by Slug but not Snail, and genes regulated by...

  10. Slug overexpression induces stemness and promotes hepatocellular carcinoma cell invasion and metastasis

    OpenAIRE

    Sun, Yu; SONG, GUO-DONG; Sun, Ning; CHEN, JIAN-QIU; YANG, SHAO-SHI

    2014-01-01

    Detection of metastasis of hepatocellular carcinoma (HCC) is crucial for early diagnosis. Epithelial-mesenchymal transition (EMT) is a common event in the metastasis of tumor cells. Slug and Snail are homologous proteins, which play an important role in EMT. The present study aimed to investigate whether Slug and Snail overexpression is associated with the invasiveness of HCC in vitro and in vivo. Invasion, colony formation and wound healing assays, as well as flow cytometry analysis, were pe...

  11. SFRP2 and Slug Contribute to Cellular Resistance to Apoptosis in Hypertrophic Scars

    OpenAIRE

    Liang Chen; Zhenxiang Wang; Shirong Li; Guangjian Zhao; Maosheng Tian; Zhicheng Sun

    2012-01-01

    Hypertrophic scars (HS) are skin disorders which occur after wounding and thermal injury. Our previous studies have suggested that secreted frizzled-related protein 2 (SFRP2) is involved in HS formation and that the suppression of SFRP2 promotes apoptosis of hypertrophic scar fibroblasts (HSFBs). However, the mechanisms have not been clarified. Previous studies revealed that Slug expression inhibits cell apoptosis, in vitro and in vivo, and SFRP2 regulates the expression of Slug in cervical c...

  12. University Loaned Normal Uranium Slug Disposition Study: University survey responses. Predecisional draft

    Energy Technology Data Exchange (ETDEWEB)

    Becker, G.W. Jr.

    1992-09-01

    During the 1950`s and 1960`s, the Atomic Energy Commission loaned rejected natural uranium slugs from the Savannah River Site to United States universities for use in subcritical assemblies. Currently, there are sixty-two universities holding 91,798 slugs, containing about 167 metric tons of natural uranium. It was originally planned that the universities would return the material to Fernald when they no longer required it. Fernald has not received slugs since it was shut down in 1988. The Department of Energy`s Office of Weapons and Materials Planning requested that the Planning Support Group develop information to assist them in facilitating the return of the unwanted slugs to one or more of their facilities and develop alternatives for the ultimate disposition of this material. This supplemental report to the University Loaned Normal Uranium Slug Disposition Study documents responses to and summarizes the results of a survey of fifty-eight universities. University contacts and survey responses covering loaned slug descriptions, historical information, radiological data, current status, and plans and schedules are documented.

  13. Recreating Riser Slugging Flow Based on an Economic Lab-sized Setup

    DEFF Research Database (Denmark)

    Hansen, Lasse; Pedersen, Simon; Yang, Zhenyu

    2013-01-01

    As a kind of periodic phenomenon, the slugging flow in the offshore oil & gas production addresses a lot of attentions, due to its limitation of production rate, periodic overload processing facilities, and even direct cause of emergent shutdown. This work studies the emulation of the riser slugg...... slug model, besides extensive experimental tests. The theoretical analysis and experimental results show that this simple setup can recreate the key features of slugging flow phenomenon reasonably precise, and it serves as a good platform for further slug control study.......As a kind of periodic phenomenon, the slugging flow in the offshore oil & gas production addresses a lot of attentions, due to its limitation of production rate, periodic overload processing facilities, and even direct cause of emergent shutdown. This work studies the emulation of the riser...... slugging flow in the offshore oil & gas production, by constructing an economical lab-sized setup in the university campus. Firstly, the construction and used components for the lab setup are illustrated; then, the constructed setup is validated by checking the consistency with some existing typical riser...

  14. An NF-kappaB and slug regulatory loop active in early vertebrate mesoderm.

    Directory of Open Access Journals (Sweden)

    Chi Zhang

    2006-12-01

    Full Text Available In both Drosophila and the mouse, the zinc finger transcription factor Snail is required for mesoderm formation; its vertebrate paralog Slug (Snai2 appears to be required for neural crest formation in the chick and the clawed frog Xenopus laevis. Both Slug and Snail act to induce epithelial to mesenchymal transition (EMT and to suppress apoptosis.Morpholino-based loss of function studies indicate that Slug is required for the normal expression of both mesodermal and neural crest markers in X. laevis. Both phenotypes are rescued by injection of RNA encoding the anti-apoptotic protein Bcl-xL; Bcl-xL's effects are dependent upon IkappaB kinase-mediated activation of the bipartite transcription factor NF-kappaB. NF-kappaB, in turn, directly up-regulates levels of Slug and Snail RNAs. Slug indirectly up-regulates levels of RNAs encoding the NF-kappaB subunit proteins RelA, Rel2, and Rel3, and directly down-regulates levels of the pro-apopotic Caspase-9 RNA.These studies reveal a Slug/Snail-NF-kappaB regulatory circuit, analogous to that present in the early Drosophila embryo, active during mesodermal formation in Xenopus. This is a regulatory interaction of significance both in development and in the course of inflammatory and metastatic disease.

  15. Experimental and computational investigations on severe slugging in a catenary riser

    Science.gov (United States)

    Duan, Jin-long; Chen, Ke; You, Yun-xiang; Gao, Song

    2017-12-01

    Severe slugging can occur in a pipeline-riser system at relatively low liquid and gas flow rates during gas-oil transportation, possibly causing unexpected damage to the production facilities. Experiments with air and water are conducted in a horizontal and downward inclined pipeline followed by a catenary riser in order to investigate the mechanism and characteristics of severe slugging. A theoretical model is introduced to compare with the experiments. The results show that the formation mechanism of severe slugging in a catenary riser is different from that in a vertical riser due to the riser geometry and five flow patterns are obtained and analyzed. A gas-liquid mixture slug stage is observed at the beginning of one cycle of severe slugging, which is seldom noticed in previous studies. Based on both experiments and computations, the time period and variation of pressure amplitude of severe slugging are found closely related to the superficial gas velocity, implying that the gas velocity significantly influences the flow patterns in our experiments. Moreover, good agreements between the experimental data and the numerical results are shown in the stability curve and flow regime map, which can be a possible reference for design in an offshore oil-production system.

  16. Snail/Slug binding interactions with YAP/TAZ control skeletal stem cell self-renewal and differentiation.

    Science.gov (United States)

    Tang, Yi; Feinberg, Tamar; Keller, Evan T; Li, Xiao-Yan; Weiss, Stephen J

    2016-09-01

    Bone-marrow-derived skeletal stem/stromal cell (SSC) self-renewal and function are critical to skeletal development, homeostasis and repair. Nevertheless, the mechanisms controlling SSC behaviour, particularly bone formation, remain ill-defined. Using knockout mouse models that target the zinc-finger transcription factors Snail or Slug, or Snail and Slug combined, a regulatory axis has been uncovered wherein Snail and Slug cooperatively control SSC self-renewal, osteoblastogenesis and bone formation. Mechanistically, Snail/Slug regulate SSC function by forming complexes with the transcriptional co-activators YAP and TAZ in tandem with the inhibition of the Hippo-pathway-dependent regulation of YAP/TAZ signalling cascades. In turn, the Snail/Slug-YAP/TAZ axis activates a series of YAP/TAZ/TEAD and Runx2 downstream targets that control SSC homeostasis and osteogenesis. Together, these results demonstrate that SSCs mobilize Snail/Slug-YAP/TAZ complexes to control stem cell function.

  17. Spatiotemporal Analysis of Predation by Carabid Beetles (Carabidae) on Nematode Infected and Uninfected Slugs in the Field

    OpenAIRE

    Bjørn Arild Hatteland; Solveig Haukeland; Steffen Roth; May Bente Brurberg; Vaughan, Ian P.; Symondson, William O. C.

    2013-01-01

    The dynamics of predation on parasites within prey has received relatively little attention despite the profound effects this is likely to have on both prey and parasite numbers and hence on biological control programmes where parasites are employed. The nematode Phasmarhabditis hermaphrodita is a commercially available biological agent against slugs. Predation on these slugs may, at the same time, result in intraguild predation on slug-parasitic nematodes. This study describes, for the first...

  18. Slug enhances invasion ability of pancreatic cancer cells through upregulation of matrix metalloproteinase-9 and actin cytoskeleton remodeling

    OpenAIRE

    Zhang, Kejun; Chen, Dong; JIAO, XUELONG; Zhang, Shaoyan; Liu, Xiangping; Cao, Jingyu; Wu, Liqun; Wang, Dongsheng

    2011-01-01

    Slug, a member of the Snail family of transcription factors, has a crucial role in the regulation of epithelial-mesenchymal transition (EMT) by suppressing several epithelial markers and adhesion molecules, including E-cadherin. A recent study demonstrated that no relationship exists between Slug and E-cadherin in pancreatic cancer. Another study showed that in malignant mesothelioma effusions Slug was associated with matrix metalloproteinase (MMP) expression, but that there was no associatio...

  19. Understanding the formation process of the liquid slug in a hilly-terrain wet natural gas pipeline

    DEFF Research Database (Denmark)

    Yang, Yan; Li, Jingbo; Wang, Shuli

    2017-01-01

    condition on the liquid slug formation is discussed including pipe diameter, inclination angle, gas superficial velocity and liquid holdup. The results show that the pipe is blocked by the liquid slug at the moment of slug formed. The pipe pressure suddenly increases, and then decreases gradually...... in the process of liquid slug formation and motion. The pipe pressure drop and liquid holdup decrease along with the increasing inclination angle of ascending pipe. On the contrary, they rise with the increase of the inclination angle of descending pipe. Higher gas superficial velocity and liquid holdup result...

  20. Modelling and control of growing slugs in horizontal multiphase pipe flows

    Directory of Open Access Journals (Sweden)

    Steinar M. Elgsæter

    2006-07-01

    Full Text Available In this paper, the use of active control to restrict the length of growing slugs in horizontal pipelines is investigated. Specifically, the paper attempts to determine if such control can be attained with realistic measurements and actuators. Simulations in OLGA2000 show that a feedback controller can use measurements or estimates of slug length to control the growth of a slug in a horizontal pipeline by partially closing inlet or outlet chokes. A control-volume approach is used to develop a low-order model of inlet choke-slug growth dynamics based on mass- and impulse balances. The resulting model is a system of nonlinear differential-algebraic equations, which is suitable for observer-design. The tuned model is found to be in good agreement with experiments and OLGA2000-simulations. Linearizations of the model are found to be observable around realistic trajectories when rates and pressures at the inlet and outlet are measured. An extended Luenberger-observer is shown to give good estimates of slug length and -position in simulations even under model uncertainty.

  1. Influence of Catalysis and Oxidation on Slug Calorimeter Measurements in Arc Jets

    Science.gov (United States)

    Nawaz, Anuscheh; Driver, Dave; TerrazasSalinas, Imelda

    2012-01-01

    Arc jet tests play a critical role in the characterization and certification of thermal protection materials and systems (TPS). The results from these arc jet tests feed directly into computational models of material response and aerothermodynamics to predict the performance of the TPS in flight. Thus the precise knowledge of the plasma environment to which the test material is subjected, is invaluable. As one of the environmental parameters, the heat flux is commonly measured. The measured heat flux is used to determine the plasma enthalpy through analytical or computational models. At NASA Ames Research Center (ARC), slug calorimeters of a geometrically similar body to the test article are routinely used to determine the heat flux. A slug calorimeter is a thermal capacitance-type calorimeter that uses the temperature rise in a thermally insulated slug to determine the heat transfer rate, see Figure 1(left). Current best practices for measuring the heat flux with a slug calorimeter are described in ASTM E457 - 96. Both the calorimeter body and slug are made of Oxygen Free High Conductivity Copper, and are cleaned before each run.

  2. Cell-State Transitions Regulated by SLUG Are Critical for Tissue Regeneration and Tumor Initiation

    Directory of Open Access Journals (Sweden)

    Sarah Phillips

    2014-05-01

    Full Text Available Perturbations in stem cell activity and differentiation can lead to developmental defects and cancer. We use an approach involving a quantitative model of cell-state transitions in vitro to gain insights into how SLUG/SNAI2, a key developmental transcription factor, modulates mammary epithelial stem cell activity and differentiation in vivo. In the absence of SLUG, stem cells fail to transition into basal progenitor cells, while existing basal progenitor cells undergo luminal differentiation; together, these changes result in abnormal mammary architecture and defects in tissue function. Furthermore, we show that in the absence of SLUG, mammary stem cell activity necessary for tissue regeneration and cancer initiation is lost. Mechanistically, SLUG regulates differentiation and cellular plasticity by recruiting the chromatin modifier lysine-specific demethylase 1 (LSD1 to promoters of lineage-specific genes to repress transcription. Together, these results demonstrate that SLUG plays a dual role in repressing luminal epithelial differentiation while unlocking stem cell transitions necessary for tumorigenesis.

  3. Snail/Slug-YAP/TAZ complexes cooperatively regulate mesenchymal stem cell function and bone formation.

    Science.gov (United States)

    Tang, Yi; Weiss, Stephen J

    2017-03-04

    Snail and Slug are zinc-finger transcription factors that play key roles in directing the epithelial-mesenchymal transition (EMT) programs associated with normal development as well as disease progression. More recent work suggests that these EMT-associated transcription factors also modulate the function of both embryonic and adult stem cells. Interestingly, YAP and TAZ, the co-transcriptional effectors of the Hippo pathway, likewise play an important role in stem cell self-renewal and lineage commitment. While direct intersections between the Snail/Slug and Hippo pathways have not been described previously, we recently described an unexpected cooperative interaction between Snail/Slug and YAP/TAZ that controls the self-renewal and differentiation properties of bone marrow-derived mesenchymal stem cells (MSCs), a cell population critical to bone development. Additional studies revealed that both Snail and Slug are able to form binary complexes with either YAP or TAZ that, together, control YAP/TAZ transcriptional activity and function throughout mouse development. Given the more recent observations that MSC-like cell populations are found in association throughout the vasculature where they participate in tissue regeneration, fibrosis and cancer, the Snail/Slug-YAP/TAZ axis is well-positioned to regulate global stem cell function in health and disease.

  4. Differential susceptibility of species of slugs to metaldehyde/bran and to methiocarb baits.

    Science.gov (United States)

    Crawford-Sidebotham, T J

    1970-12-01

    Laboratory experiments were designed to study differential susceptibility of nine species of slugs to metaldehyde/bran and to methiocarb baits. Differential susceptibility was found between some of the species for each type of bait, both immediately after baiting and also after a 48 h recovery period. Thus neither type of bait is suitable for use in ecological investigations. This conclusion was supported by evidence that interspecific behavioural interactions occurred when metaldehyde, but not methiocarb, baits were used.At the same time the relative efficiency of the two types of baits as molluscicides was estimated. Methiocarb was shown to be a better molluscicide because, not only did it initially poison more slugs than did metaldehyde, but also a number of the slugs initially poisoned by metaldehyde recovered during the following 48 h period, whereas this did not happen with methiocarb. The similarity between these results and those obtained from field experiments by other workers is discussed.

  5. Influence of riser-induced slugs on the downstream separation processes

    DEFF Research Database (Denmark)

    Pedersen, Simon; Løhndorf, Petar Durdevic; Yang, Zhenyu

    2017-01-01

    linked to a de-oiling hydrocyclone, based on experimental tests performed on a laboratory testing facility. Several scenarios are compared, while three PID controllers’ coefficients are kept constant for all the tests: The separator pressure, water level, and hydrocyclone pressure-drop-ratio (PDR......) controllers. Each respective scenario makes a comparison between uncontrolled, open-, and closed-loop anti-slug control configurations. It is concluded that both open- and closed-loop anti-slug control strategies improve the water level and PDR setpoint tracking equally well, but that the closed-loop strategy...... gives the best average production rate. Furthermore, it is confirmed that a PWT-ecient riser bottom pressure (Prb) anti-slug control strategy has to guarantee stabilization of the mass inflow rate to the separator for archiving acceptable hydrocyclone separation. A stable !sep;in is observed...

  6. Slug tests in unconfined formations: an assessment of the bouwer and rice technique

    Science.gov (United States)

    Hyder, Z.; Butler, J.J.

    1995-01-01

    The slug test is one of the most common techniques for the in situ estimation of hydraulic conductivity in unconfined flow systems. Recently, Bouwer and Rice model describing the flow of ground water in response to a slug test in an unconfirmed flow system has been proposed. For slug tests performed in homogeneous, isotropic formations that would be classified as aquifiers, the Bouwer and Rice model provides estimates within 30% of actual field values. In less-permeable, clay-rich formations, however, estimates may overpredict formation conductivity by more than 100%. The Bouwer and Rice model introduces the largest error in the presence of low permeability skin. Uncertainty about anisotropy can also be the source of considerable error.

  7. Control of slug damage to oilseed rape and wheat with imidacloprid seed dressings in laboratory and field experiments

    NARCIS (Netherlands)

    Simms, L.C.; Ester, A.; Wilson, M.J.

    2006-01-01

    Slugs are common pests of oilseed and cereal crops in Europe and are currently controlled using bait pellets that often fail to give adequate protection: Here we investigate the potential of the broad-spectrum insecticide imidacloprid, previously suggested to have activity against slugs, to control

  8. Fluidization behavior in a circulating slugging fluidized bed reactor. Part I: Residence time and residence time distribution of polyethylene solids

    NARCIS (Netherlands)

    van Putten, I.C.; van Sint Annaland, M.; Weickert, G.

    2007-01-01

    Square nosed slugging fluidization behavior in a circulating fluidized bed riser using a polyethylene powder with a very wide particle size distribution was studied. In square nosed slugging fluidization the extent of mixing of particles of different size depends on the riser diameter, gas velocity,

  9. Learning control for riser-slug elimination and production-rate optimization for an offshore oil and gas production process

    DEFF Research Database (Denmark)

    Pedersen, Simon; Løhndorf, Petar Durdevic; Yang, Zhenyu

    2014-01-01

    Slugging flow in the offshore oil & gas production attracts lot of attention due to it's limitation of production rate, periodic overload on processing facilities, and even direct cause of emergency shutdown. This work aims at two correlated objectives: (i) Preventing slugging flow; and meanwhile...

  10. Naturally-Forced Slug Flow Expander for Application in a Waste-Heat Recovery Cycle

    Directory of Open Access Journals (Sweden)

    Ben de Witt

    2014-11-01

    Full Text Available This paper investigates a slug-flow expander (SFE for conversion of high-pressure gas/vapor into kinetic energy of liquid slugs. The energy transfer from high-pressure to kinetic energy is quantified using thrust plate measurements. Non-dimensional thrust data is used to quantify performance by normalizing measured thrust by thrust for the same water flow rate at zero air flow rate. A total of 13 expander configurations are investigated and geometries with the shortest cavity length and the smallest exit diameter are found to result in the largest non-dimensional thrust increase. Results show that thrust augmentation increases with the initiation of slug flow in the SFE. The analysis performed on the normalized thrust readings suggested that as the water and air flow were increased to critical conditions, the liquid slugs produced by the SFE augmented the thrust measurements. The final performance evaluation was based on linear regression of the normalized thrust measurements where slug flow was generated for each SFE architecture. Greater magnitudes of the slope from the linear regression indicated the propensity of the SFE to augment thrust. This analysis confirmed that for the SFE configurations over the range of values investigated, the SFE increased thrust up to three times its original value at no air flow. Given the inherent multiphase nature of the slug-flow expander, application to systems involving expansion of wetting fluids (water as part of a waste-heat recovery system or air with water droplet formation (as part of a compressed-air energy storage system could be considered.

  11. The manufacture of enriched uranium fuel slugs for the Experimental Breeder Reactor.

    Energy Technology Data Exchange (ETDEWEB)

    Shuck, Author B.

    1953-04-20

    This report describes the specifications, materials and the sequence of operations used to found and fabricate 4 the first charge of enriched uranium fuel in the Experimental Breeder Reactor. The work was governed by the following principles: a. That the fuel be of correct composition, dimension and metallurgical condition for use in the reactor. b. That a maximum yield of finished fuel slugs from the quantity of uranium available for the program be achieved. c. That the residues be in a form which can be recovered by chemical or other means. d. That a detailed record be kept in such form that a complete history of each fuel slug be available.

  12. Slugging their way to immortality: driving mammary epithelial cells into a stem cell-like state.

    Science.gov (United States)

    Soady, Kelly; Smalley, Matthew J

    2012-09-10

    Delineating the molecular factors that define and maintain the mammary stem cell state is vital for understanding normal development and tumourigenesis. A recent study by Guo and colleagues identifies two master transcriptional regulators of mammary stem cells, Slug and Sox9, ectopic expression of which confers stem cell attributes on differentiated mammary epithelial cells. Slug and Sox9 expression was also shown to determine in vivo metastatic potential of human breast cancer cell lines. Understanding these factors in the context of normal lineage differentiation is an important step toward elucidating the mammary epithelial cell hierarchy and the origins of cancer stem cells.

  13. Dynamics of a two-phase flow through a minichannel: Transition from churn to slug flow

    Science.gov (United States)

    Górski, Grzegorz; Litak, Grzegorz; Mosdorf, Romuald; Rysak, Andrzej

    2016-04-01

    The churn-to-slug flow bifurcations of two-phase (air-water) flow patterns in a 2mm diameter minichannel were investigated. With increasing a water flow rate, we observed the transition of slugs to bubbles of different sizes. The process was recorded by a digital camera. The sequences of light transmission time series were recorded by a laser-phototransistor sensor, and then analyzed using the recurrence plots and recurrence quantification analysis (RQA). Due to volume dependence of bubbles velocities, we observed the formation of periodic modulations in the laser signal.

  14. Study on noise caused by slug flow through a capillary tube; Shibori ni kiinsuru slug ryu ni yoru soon no jikkenteki kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Kannon, T. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

    1997-07-25

    Noise problems caused by two-phase flows in tubes connected to air-cooled heat exchangers have become more serious. since the level of air conditioner fan noise has decreased. In particular, when a slug flow occurs. the noise level greatly increases. In this study, an air-water two-phase flow was used to create a slug flow through a capillary tube in order to investigate the mechanism of the noise. We also investigated the relationship between the gas bubble state and the pressure pulsation by changing the void fraction. The results show that the pressure pulsation level, which is proportional to the noise level, is determined by the magnitude and the density of the impact pressure pulsation caused by the expansion of the gas at the end of the capillary tube. 11 refs., 14 figs.

  15. Imaging the liquid film layer of slug flow within a microreactor

    Science.gov (United States)

    Pouya, Shahram; Koochesfahani, Manoochehr; Greytak, Andrew; Nocera, Daniel; Bawendi, Moungi; Dydek, Vicki; Jensen, Klavs

    2009-11-01

    Segmented gas-liquid microreactors have gained attraction for high throughput material synthesis and sample processing in chemistry and biotechnology. The performance of the segmented gas-liquid microfluidic reactor derives from the uniformity of the gas-liquid segment lengths and the mixing that occurs within the liquid segment confined between gas slugs. The mixing process is a consequence of the recirculating flow that is set up within the liquid slugs. An important aspect of this flow geometry is that the liquid segments are not completely isolated but interconnected through a thin liquid film. Therefore, the behavior of the film layer and the flow field within the slugs are of great importance in hydrodynamics of the microreactor flow and improving the efficiency of such reactors. We present preliminary results of imaging, with quantum dots, the thin film layer surrounding the gas bubbles. The results are presented for stable slug flow of Ethanol/Nitrogen within a PDMS microreactor with channel size of 300x250 micron.

  16. Transient drift flux modelling of severe slugging in pipeline-riser systems

    NARCIS (Netherlands)

    Malekzadeh, R.; Belfroid, S.P.C.; Mudde, R.F.

    2012-01-01

    A large number of pipelines in the petroleum industry simultaneously transport gas and liquid. Transient behaviour of multiphase flow is frequently encountered in these pipelines. A common example is severe slugging that can occur in multiphase flow systems where a pipeline segment with a downward

  17. Searching the Human Genome for Snail and Slug With DNA@Home.

    Science.gov (United States)

    Zarns, Kristopher; Desell, Travis; Nechaev, Sergei; Dhasarathy, Archana

    2015-01-01

    DNA@Home is a volunteer computing project that aims to use Gibbs Sampling for the identification and location of DNA control signals on full genome-scale datasets. A fault tolerant and asynchronous implementation of Gibbs sampling using the Berkeley Open Infrastructure for Network Computing (BOINC) was used to identify the location of binding sites of the SNAI1 (Snail) and SNAI2 (Slug) transcription factors across the human genome. Genes regulated by Slug but not Snail, and genes regulated by Snail but not Slug provided two datasets with known motifs. These datasets contained up to 994 DNA sequences which to our knowledge is largest scale use of Gibbs sampling for discovery of binding sites. 1000 parallel sampling walks were used to search for the presence of 1, 2 or 3 possible motifs using small, medium, and full size sets of these sequences. These runs were performed over a period of two months using over 1500 volunteered computing hosts and generated over 2.2 Terabytes of sampling data. High performance computing resources were used for post processing. This paper presents intra and inter walk analyses used to determine walk convergence. The results were validated against current biological knowledge of the Snail and Slug promoter regions and present avenues for further biological study.

  18. Severe slugging in gas-liquid two-phase pipe flow

    NARCIS (Netherlands)

    Malekzadeh, R.

    2012-01-01

    transportation facilities. In an offshore oil and gas production facility, pipeline-riser systems are required to transport two-phase hydrocarbons from subsurface oil and gas wells to a central production platform. Severe slugs reaching several thousands pipe diameters may occur when transporting

  19. Slugs as target or non-target organisms for environmental chemicals

    OpenAIRE

    Triebskorn, R.; Henderson, I. F.; Martin, A.; Köhler, H.-R.

    1996-01-01

    The ability of slugs (Deroceras reticulatum) to survive exposure to various chemical stressors such as molluscicides ( carbamates, metaldehyde, ironchelates) or other environmental pollutants (heavy metals, pesticides) was investigated using x-ray analyses, autoradiography, filter electron microscopy, enzyme histochemistry, enzymatics, electron microscopy, and stress protein analyses. Uptake pathways, target sites, modes of action and general responses in the animals were studied, and the res...

  20. Numerical validation of gas-liquid slug flow inside horizontal pipe ...

    African Journals Online (AJOL)

    No Abstract. Keywords: numerical simulation; two phase flow; VOF technique; CFD; modeling; slug flow. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

  1. Acquired phototrophy through retention of functional chloroplasts increases growth efficiency of the sea slug Elysia viridis.

    Directory of Open Access Journals (Sweden)

    Finn A Baumgartner

    Full Text Available Photosynthesis is a fundamental process sustaining heterotrophic organisms at all trophic levels. Some mixotrophs can retain functional chloroplasts from food (kleptoplasty, and it is hypothesized that carbon acquired through kleptoplasty may enhance trophic energy transfer through increased host growth efficiency. Sacoglossan sea slugs are the only known metazoans capable of kleptoplasty, but the relative fitness contributions of heterotrophy through grazing, and phototrophy via kleptoplasts, are not well understood. Fitness benefits (i.e. increased survival or growth of kleptoplasty in sacoglossans are commonly studied in ecologically unrealistic conditions under extended periods of complete darkness and/or starvation. We compared the growth efficiency of the sacoglossan Elysia viridis with access to algal diets providing kleptoplasts of differing functionality under ecologically relevant light conditions. Individuals fed Codium fragile, which provide highly functional kleptoplasts, nearly doubled their growth efficiency under high compared to low light. In contrast, individuals fed Cladophora rupestris, which provided kleptoplasts of limited functionality, showed no difference in growth efficiency between light treatments. Slugs feeding on Codium, but not on Cladophora, showed higher relative electron transport rates (rETR in high compared to low light. Furthermore, there were no differences in the consumption rates of the slugs between different light treatments, and only small differences in nutritional traits of algal diets, indicating that the increased growth efficiency of E. viridis feeding on Codium was due to retention of functional kleptoplasts. Our results show that functional kleptoplasts from Codium can provide sacoglossan sea slugs with fitness advantages through photosynthesis.

  2. PRODUCTION OF MASSIVE PROFILE SLUGS AND WEAR-RESISTANT CASTINGS FOR DETAILS OF IMPORTANT ASSIGNMENT

    Directory of Open Access Journals (Sweden)

    M. A. Saikov

    2006-01-01

    Full Text Available The peculiarities of production of massive wearresisting castings and profile slugs for the details of important assignment are studied. It is offered to use economdoped antifriction cast irons and the ways of casting with intensive heat-exchange for creation of such castings.

  3. A model for cell type localization in the migrating slug of ...

    Indian Academy of Sciences (India)

    Abstract. The three basic cell types in the migrating slug of Dictyostelium discoideum show differential chemotactic response to cyclic AMP (cAMP) and differential sensitivity to suppression of the chemotaxis by ammonia. The values of these parameters indicate a progressive maturation of chemotactic properties during the ...

  4. FORMING OF MECHANICAL CHARACTERISTICS OF THE SLUGS OF TITANIC ALLOY BT23 AT THERMAL TREATMENT

    Directory of Open Access Journals (Sweden)

    V. N. Fedulov

    2005-01-01

    Full Text Available Тhе changings of the initial plate structure of alloy BT23 at running of high-temperature thermal treatment of large-sized slugs with heating up to 650- 950 eC and cooling on air and in water and their influence on forming of complex of mechanical characteristics are examined.

  5. Lactic Acid Extraction and Mass Transfer Characteristics in Slug Flow Capillary Microreactors

    NARCIS (Netherlands)

    Susanti, S.; Winkelman, J.G.N.; Schuur, Boelo; heeres, h.j.; Yue, J.

    2016-01-01

    Capillary microreactors operated under the slug flow regime were investigated for the separation of lactic acid from the aqueous phase using liquid–liquid reactive extraction. The experiments were performed at a 1:1 flow ratio of the aqueous to organic phases in a setup consisting of an inlet Y-type

  6. The applicability of slug tests in fractured-rock formations | van ...

    African Journals Online (AJOL)

    The estimated value is dependent on the flow thickness (thickness of the part of the aquifer in which flow occurs due to the slug input). If this thickness of flow is known, the estimated T-value is more representative of that of the fracture zone. By using the total thickness of the formation for the estimation of the K-value in

  7. Experimental investigation of terrain slugging formation, evolution and potential for mitigation

    NARCIS (Netherlands)

    Brasjen, B.J.; Hansen, J.H.; Schiferli, W.; Belfroid, S.P.C.

    2013-01-01

    The formation and evolution of slugs formed in air/water mixture in inclined pipes has been characterized as a function of flow conditions, pipe length and inclination angle. Good agreement was found with model predictions and experimental observations available from literature. Two regimes were

  8. A nonlinear flow-transition criterion for the onset of slugging in horizontal channels and pipes

    Science.gov (United States)

    Campbell, Bryce K.; Liu, Yuming

    2016-08-01

    In this work, the interfacial instability and transition of a two-fluid flow from a stratified state to large amplitude waves or slugs is considered. By combining an asymptotic approximation of the linear Orr-Sommerfeld analysis with nonlinear resonant wave interaction theory, a novel nonlinear slug-transition criterion is derived. This criterion corresponds to a bounding condition on the upper fluid's velocity in order to limit the amount of energy (provided by the linear instability) which is transferred to long waves through resonant wave interactions. It is proposed that such a condition can predict the formation of large-amplitude long waves and/or slugs. Quantitative comparisons of the onset of slugging are made between the prediction by the nonlinear transition criterion and the experimental measurements carried out in a horizontal square channel. Good agreement is observed. An additional heuristic model is developed which generalizes the transition criterion to flow through horizontal pipes. Comparisons are made for flows through different pipe diameters and over a wide range of fluid properties. Good agreement between the present theoretical predictions and the experimental measurements is also observed.

  9. Production Test No. 305-9-P, poisoning effectiveness and uniformity of myrnalloy slugs. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Wende, C.W.J.

    1946-04-02

    This report discusses the poisoning effectiveness and uniformity of the first production batch of 33 myrnalloy slugs which was tested in the 305 Test Pile on February 26, 1946, prior to charging into the D Pile in accordance with Production Test No. 105-49-P, supplement A.

  10. Slugs in a large diameter column with air and high viscosity silicone oil

    Science.gov (United States)

    Hasan, Abbas; Azzopardi, Barry

    2014-11-01

    Very little information is known about the behaviour of high viscous liquids (> 100 Pa.s) in two phase slug flows. Experiments were carried out to study the behaviour of silicone oil (300 Pa.s) in gas bubble column using electrical capacitance tomography technique. The main aim of this paper is to study the characteristics and parameters of gas-liquid slug flows through large scale experiments with realistic liquids in a large diameter pipe (240 mm). These include; mean void fraction, Taylor bubble velocity, lengths of liquid slugs and Taylor bubbles, liquid film and fraction flowing down past the Taylor bubble. It was found that the gas mainly travels as large bubbles with ellipsoidal shape which occupy a significant portion of the pipe cross section with tiny bubbles in the liquid. In addition, the top surface of the gas-liquid column experiences a periodic oscillation (rising and falling) as the large bubbles rise to the top surface and burst. The results presented in this work have been compared with previous studies to show the effects of the viscosity and the pipe diameter on the behaviour of large bubbles in gas-liquid two phase slug flows. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  11. Thevetia peruviana (Family: Apocynaceae in the control of slug and snail pests

    Directory of Open Access Journals (Sweden)

    A. Panigrahi

    1994-06-01

    Full Text Available An aqueous extract prepared from Kernels of the fruit of Thevetia peruviana (Pers. Schumann (Family : Apocynaceae was found under experimental conditions, to be toxic ti the slug Laevicaulis alte (Férussac and the snail Achatina fulica Bowdich, the important agrihorticultural pests of Indo-Pacific countries. Concentrations as low as 1% (w/v killed all the slugs exposed in less than 981.00 (± SD 22.76 min, and 2% of the extract killed 100% of the slugs L. alte and 50%, 50% and 30% of the snail A. fulica in between 92.34 (± SD 6.63 - 321.33 (± SD 4.14 and 271.20 (± SD 17.54 - 298.26 (± SD 16.69 min respectively. The most effective concentration of the extract was 20%; it killed 100% of exposed slugs and snails within a short time (40-50 and 90-1440 min respectively when the extract was exposed on the soil in experimental trays or when it was applied to potato slices offered as food to the gastropods.

  12. Gas6 induces cancer cell migration and epithelial–mesenchymal transition through upregulation of MAPK and Slug

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yunhee [Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Lee, Mira [Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Kim, Semi, E-mail: semikim@kribb.re.kr [Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of)

    2013-04-26

    Highlights: •We investigated the molecular mechanisms underlying Gas6-mediated cancer cell migration. •Gas6 treatment and subsequent Axl activation induce cell migration and EMT via upregulation of Slug. •Slug expression mediated by Gas6 is mainly through c-Jun and ATF-2 in an ERK1/2 and JNK-dependent manner. •The Gas6/Axl-Slug axis may be exploited as a target for anti-cancer metastasis therapy. -- Abstract: Binding of Gas6 to Axl (Gas6/Axl axis) alters cellular functions, including migration, invasion, proliferation, and survival. However, the molecular mechanisms underlying Gas6-mediated cell migration remain poorly understood. In this study, we found that Gas6 induced the activation of JNK and ERK1/2 signaling in cancer cells expressing Axl, resulting in the phosphorylation of activator protein-1 (AP-1) transcription factors c-Jun and ATF-2, and induction of Slug. Depletion of c-Jun or ATF-2 by siRNA attenuated the Gas6-induced expression of Slug. Slug expression was required for cell migration and E-cadherin reduction/vimentin induction induced by Gas6. These results suggest that Gas6 induced cell migration via Slug upregulation in JNK- and ERK1/2-dependent mechanisms. These data provide an important insight into the molecular mechanisms mediating Gas6-induced cell migration.

  13. On-demand generation and mixing of liquid-in-gas slugs with digitally-programmable composition and size.

    Science.gov (United States)

    Chen, Yi-Chun; Liu, Kan; Shen, Clifton Kwang-Fu; van Dam, R Michael

    2015-08-01

    Microscopic droplets or slugs of mixed reagents provide a convenient platform for performing large numbers of isolated biochemical or chemical reactions for many screening and optimization applications. Myriad microfluidic approaches have emerged for creating droplets or slugs with controllable size and composition, generally using an immiscible carrier fluid to assist with the formation or merging processes. We report a novel device for generation of liquid slugs in air when the use of a carrier liquid is not compatible with the application. The slug generator contains two adjacent chambers, each of which has a volume that can be digitally adjusted by closing selected microvalves. Reagents are filled into the two chambers, merged together into a contiguous liquid slug, ejected at the desired time from the device using gas pressure, and mixed by flowing in a downstream channel. Programmable size and composition of slugs is achieved by dynamically adjusting the volume of each chamber prior to filling. Slug formation in this fashion is independent of fluid properties and can easily be scaled to mix larger numbers of reagents. This device has already been used to screen monomer ratios in supramolecular nanoparticle assembly and radiolabeling conditions of engineered antibodies, and here we provide a detailed description of the underlying device.

  14. Evaluation of the effects of the radial constant-head boundary in slug tests

    Science.gov (United States)

    Dai, Yunfeng; Zhou, Zhifang; Zhao, Yanrong; Cui, Ziteng

    2015-03-01

    A semianalytical model of slug tests, conducted in a completely penetrating well within a radial constant-head boundary, was derived. The model, based on the Cooper et al. (1967) model, estimates the hydraulic conductivity and storage coefficient through the matching of type curves. Type curves of the semianalytical solution were plotted, and the effect of the distance of the radial constant-head boundary is discussed. For different storage coefficients, the critical distances of the effect of the constant-head boundary were determined. The effect of the storage coefficient on the response of the water head in slug tests with a radial constant-head boundary of a certain distance is also shown. To verify the model, laboratory slug-test experiments were carried out using a cylindrical test platform, in which an artificial confined coarse-sand aquifer was built. Pumping tests were also executed using the test platform. The Cooper et al. (1967) model and new semianalytical model were used to analyze measurements; the hydraulic conductivity and storage coefficient determined using the two methods were compared to demonstrate the importance of the radial constant-head boundary. A model considering the inertial effect was also used to analyze the slug-test measurements, and although the water head response did not oscillate greatly, the inertial effect affected the slug-test calculation result. The laboratory experiments indicate that the proposed semianalytical model is reasonable and reliable. Cooper HH, Bredehoeft JD, Papadopulos IS (1967) Response of a finite-diameter well to an instantaneous charge of water, Water Resour Res 3(1):263-269.

  15. Investigation of severe slugging under flow conditions of a parabolic trough power plant with direct steam generation

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Alexander [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Reactor Safety

    2016-07-01

    The DISS test facility at the Plataforma Solar de Almeria, Spain, produces high pressure steam directly within the parabolic trough collectors. Two collectors are connected with a U-shaped connection pipe which can suffer under the flow phenomenon of severe slugging at low mass flow operation. The objective is to investigate numerically the flow situations with ATHLET and state the relevance of severe slugging in the installed U-shaped pipes. The simulation results reveal that normal operation conditions are uncritical and no severe slugging can be expected.

  16. Drusia (Escutiella alexantoni n. sp. (Gastropoda, Pulmonata, Parmacellidae, a new terrestrial slug from the Atlantic coast of Morocco

    Directory of Open Access Journals (Sweden)

    Martínez–Ortí, A.

    2013-06-01

    Full Text Available We describe a new parmacellid, Drusia (Escutiella alexantoni n. sp. from the Moroccan Atlantic coast. The species most closely related to the new taxon are D. (E. deshayesii and D. (D. valenciennii. The new parmacellid differs from D. (E deshayesii mainly by the presence of external spots and bands on both the back and the shield, a reproductive system with uneven atrial appendices of the horn–shaped organ, and a different reticulated pattern of the inner epiphallus. It differs from D. (D. valenciennii mainly for the appearance of the shell and the pattern and disposition of the bumps inside the penis, the presence of an elbow–shape in this organ, and the reticulated appearance of the inner wall of the epiphallus. An updated dichotomous key of the family Parmacellidae is provided.

  17. A Study of Bubble and Slug Gas-Liquid Flow in a Microgravity Environment

    Science.gov (United States)

    McQuillen, J.

    2000-01-01

    The influence of gravity on the two-phase flow dynamics is obvious.As the gravity level is reduced,there is a new balance between inertial and interfacial forces, altering the behavior of the flow. In bubbly flow,the absence of drift velocity leads to spherical-shaped bubbles with a rectilinear trajectory.Slug flow is a succession of long bubbles and liquid slug carrying a few bubbles. There is no flow reversal in the thin liquid film as the long bubble and liquid slug pass over the film. Although the flow structure seems to be simpler than in normal gravity conditions,the models developed for the prediction of flow behavior in normal gravity and extended to reduced gravity flow are unable to predict the flow behavior correctly.An additional benefit of conducting studies in microgravity flows is that these studies aide the development of understanding for normal gravity flow behavior by removing the effects of buoyancy on the shape of the interface and density driven shear flows between the gas and the liquid phases. The proposal calls to study specifically the following: 1) The dynamics of isolated bubbles in microgravity liquid flows will be analyzed: Both the dynamics of spherical isolated bubbles and their dispersion by turbulence, their interaction with the pipe wall,the behavior of the bubbles in accelerated or decelerated flows,and the dynamics of isolated cylindrical bubbles, their deformation in accelerated/decelerated flows (in converging or diverging channels), and bubble/bubble interaction. Experiments will consist of the use of Particle Image Velocimetry (PIV) and Laser Doppler Velocimeters (LDV) to study single spherical bubble and single and two cylindrical bubble behavior with respect to their influence on the turbulence of the surrounding liquid and on the wall 2) The dynamics of bubbly and slug flow in microgravity will be analyzed especially for the role of the coalescence in the transition from bubbly to slug flow (effect of fluid properties and

  18. A mini slug test method for determination of a local hydraulic conductivity of an unconfined sandy aquifer

    DEFF Research Database (Denmark)

    Hinsby, Klaus; Bjerg, Poul Løgstrup; Andersen, Lars J.

    1992-01-01

    A new and efficient mini slug test method for the determination of local hydraulic conductivities in unconfined sandy aquifers is developed. The slug test is performed in a small-diameter (1 inch) driven well with a 0.25 m screen just above the drive point. The screened drive point can be driven...... from level to level and thereby establish vertical profiles of the hydraulic conductivity. The head data from the test well are recorded with a 10 mm pressure transducer, and the initial head difference required is established by a small vacuum pump. The method described has provided 274 spatially...... distributed measurements of a local hydraulic conductivity at a tracer test site at Vejen, Denmark. The mini slug test results calculated by a modified Dax slug test analysing method, applying the elastic storativity in the Dax equations instead of the specific yield, are in good accordance with the results...

  19. Combination of rapamycin, CI-1040, and 17-AAG inhibits metastatic capacity of prostate cancer via Slug inhibition.

    Directory of Open Access Journals (Sweden)

    Guanxiong Ding

    Full Text Available Though prostate cancer (PCa has slow progression, the hormone refractory (HRCP and metastatic entities are substantially lethal and lack effective treatments. Transcription factor Slug is critical in regulating metastases of various tumors including PCa. Here we studied targeted therapy against Slug using combination of 3 drugs targeting 3 pathways respectively converging via Slug and further regulating PCa metastasis. Using in vitro assays we confirmed that Slug up-regulation incurred inhibition of E-cadherin that was anti-metastatic, and inhibited Bim-regulated cell apoptosis in PCa. Upstream PTEN/Akt, mTOR, Erk, and AR/Hsp90 pathways were responsible for Slug up-regulation and each of these could be targeted by rapamycin, CI-1040, and 17-AAG respectively. In 4 PCa cell lines with different traits in terms of PTEN loss and androgen sensitivity we tested the efficacy of mono- and combined therapy with the drugs. We found that metastatic capacity of the cells was maximally inhibited only when all 3 drugs were combined, due to the crosstalk between the pathways. 17-AAG decreases Slug expression via blockade of HSP90-dependent AR stability. Combination of rapamycin and CI-1040 diminishes invasiveness more potently in PCa cells that are androgen insensitive and with PTEN loss. Slug inhibited Bim-mediated apoptosis that could be rescued by mTOR/Erk/HSP90 inhibitors. Using mouse models for circulating PCa DNA quantification, we found that combination of mTOR/Erk/HSP90 inhibitors reduced circulating PCa cells in vivo significantly more potently than combination of 2 or monotherapy. Conclusively, combination of mTOR/Erk/Hsp90 inhibits metastatic capacity of prostate cancer via Slug inhibition.

  20. Predation by beetles (Carabidae, Staphylinidae) on eggs and juveniles of the Iberian slug Arion lusitanicus in the laboratory

    OpenAIRE

    Hatteland, Bjorn; Grutle, K.; Mong, C. E.; Skartveit, J.; Symondson, William Oliver Christian; Solhøy, T.

    2010-01-01

    Arion lusitanicus has become a major pest species in western Norway in the last few years. This species originates from southern Europe but has been spread by humans over large parts of central and northern Europe during recent decades. Slugs have traditionally been controlled by the use of molluscicides; but, as these may have serious ecological side effects, biological control of slugs is highly desirable. Potential biological control agents include nematodes, gastropods and ...

  1. The unique deep sea—land connection: interactive 3D visualization and molecular phylogeny of Bathyhedyle boucheti n. sp. (Bathyhedylidae n. fam.—the first panpulmonate slug from bathyal zones

    Directory of Open Access Journals (Sweden)

    Timea P. Neusser

    2016-12-01

    Full Text Available The deep sea comprises vast unexplored areas and is expected to conceal significant undescribed invertebrate species diversity. Deep waters may act as a refuge for many relictual groups, including elusive and enigmatic higher taxa, but the evolutionary pathways by which colonization of the deep sea has occurred have scarcely been investigated. Sister group relationships between shallow water and deep sea taxa have been documented in several invertebrate groups, but are unknown between amphibious/terrestrial and deep-sea species. Here we describe in full and interactive 3D morphoanatomical detail the new sea slug species Bathyhedyle boucheti n. sp., dredged from the continental slope off Mozambique. Molecular and morphological analyses reveal that it represents a novel heterobranch gastropod lineage which we establish as the new family Bathyhedylidae. The family is robustly supported as sister to the recently discovered panpulmonate acochlidian family Aitengidae, which comprises amphibious species living along the sea shore as well as fully terrestrial species. This is the first marine-epibenthic representative among hedylopsacean Acochlidiida, the first record of an acochlidian from deep waters and the first documented panpulmonate deep-sea slug. Considering a marine mesopsammic ancestor, the external morphological features of Bathyhedyle n. gen. may be interpreted as independent adaptations to a benthic life style in the deep sea, including the large body size, broad foot and propodial tentacles. Alternatively, the common ancestor of Bathyhedylidae and Aitengidae may have been a macroscopic amphibious or even terrestrial species. We hypothesize that oophagy in the common ancestor of Aitengidae and Bathyhedylidae might explain the impressive ecological and evolutionary flexibility in habitat choice in the Acochlidiida.

  2. Suppression of Invasion and Metastasis of Triple-Negative Breast Cancer Lines by Pharmacological or Genetic Inhibition of Slug Activity

    Directory of Open Access Journals (Sweden)

    Giovanna Ferrari-Amorotti

    2014-12-01

    Full Text Available Most triple-negative breast cancers (TNBCs exhibit gene expression patterns associated with epithelial-to-mesenchymal transition (EMT, a feature that correlates with a propensity for metastatic spread. Overexpression of the EMT regulator Slug is detected in basal and mesenchymal-type TNBCs and is associated with reduced E-cadherin expression and aggressive disease. The effects of Slug depend, in part, on the interaction of its N-terminal SNAG repressor domain with the chromatin-modifying protein lysine demethylase 1 (LSD1; thus, we investigated whether tranylcypromine [also known as trans-2-phenylcyclopropylamine hydrochloride (PCPA or Parnate], an inhibitor of LSD1 that blocks its interaction with Slug, suppresses the migration, invasion, and metastatic spread of TNBC cell lines. We show here that PCPA treatment induces the expression of E-cadherin and other epithelial markers and markedly suppresses migration and invasion of TNBC cell lines MDA-MB-231 and BT-549. These effects were phenocopied by Slug or LSD1 silencing. In two models of orthotopic breast cancer, PCPA treatment reduced local tumor growth and the number of lung metastases. In mice injected directly in the blood circulation with MDA-MB-231 cells, PCPA treatment or Slug silencing markedly inhibited bone metastases but had no effect on lung infiltration. Thus, blocking Slug activity may suppress the metastatic spread of TNBC and, perhaps, specifically inhibit homing/colonization to the bone.

  3. Gas Bubbles and Slugs Crossover in Air-Water Two-phase Flow by Multifractals

    Science.gov (United States)

    Gorski, Grzegorz; Litak, Grzegorz; Mosdorf, Romuald; Rysak, Andrzej

    2017-05-01

    Slugs and bubbles two-phase flow patterns dynamics in a minichannel are analysed. During the experiment, the volume flow rates of air and water were changed. We study transition of bubbles to slugs two-phase flow patterns using Fourier and multifractal approaches to optical transitivity signal. The sequences of light transmission time series are recorded by a laser-phototransistor sensor. Multifractal analysis helps to identify the two-phase structure and estimate the signal complexity. Especially, we discuss occurrence and identification of a self-aggregation phenomenon. These results are compared to corresponding Fourier spectra. The results indicate that the fractality is a an important factor influencing the distribution of the gas phase in water.

  4. The analysis of fuel constituent redistribution for ternary metallic fuel slug

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byoung Oon; Lee, Dong Uk; Kim, Young Kyun; Chang, Jin Wook; Lee, Ki Bok; Kim, Young Il

    2004-02-01

    U-TRU-Zr metallic alloy is being considered as the fuel slug for the proliferation resistance core of KALIMER. The radial fuel constituent migration is a general phenomenon in the metallic alloys. This phenomenon may affect the in-reactor performance of metallic fuel rods, influencing such factors as melting temperature, thermal conductivity, power generation rate, phase boundaries and eutectic melting of the fuel slug. Thus, constituent redistribution modeling is essential when developing a metallic fuel performance code. The constituent migration model adopted in this report was based on the Ishida's model and Hofman's theory. A subroutine program has been made and installed into the MACSIS code to simulate constituent redistribution. The radial profile of Zr redistribution was calculated for the ternary metallic fuel, and compared with the measured data.

  5. Slug Test in a Large Dip Angle Fracture Zone: Model and Field Experiment

    Directory of Open Access Journals (Sweden)

    Ying Liu and Chia-Shyun Chen

    2015-01-01

    Full Text Available A single-porosity model is developed to deal with a fracture zone slug test in a large dip angle by assuming the fracture zone causes a downward regional flow. For the oscillatory response, a larger dip angle causes larger amplitude while introduces little impact on period. The effective water length, an important parameter necessary for analyzing the oscillatory response, is proven to be independent of the dip angle and can be evaluated using the available horizontal formation methods. The dip angle effect is more pronounced for a larger storage coefficient. An empirical relationship is developed to evaluate the limiting dip angle, below which the dip angle effect is negligible. Field data analysis of a slug test in a _ dip angle fracture zone indicates that neglecting the dip angle can result in a 27% transmissivity over estimation and a 53% storage coefficient under estimation.

  6. Gas Slug Microfluidics: A Unique Tool for Ultrafast, Highly Controlled Growth of Iron Oxide Nanostructures.

    Science.gov (United States)

    Larrea, Ane; Sebastian, Victor; Ibarra, Alfonso; Arruebo, Manuel; Santamaria, Jesus

    2015-06-23

    The use of nanomaterials in real life applications is often hampered by our inability to produce them in large quantities while preserving their desired properties in terms of size, shape, and crystalline phase. Here we present a novel continuous method to synthesize nanostructures with an unprecedented degree of control regarding their properties. In particular, the excellent properties of microreactors for chemical synthesis are enhanced by the introduction of gas slugs of tailored composition. Slug dynamics accelerate mixing, reduce processing times (from hours in batch processes to minutes or even seconds), and, depending on the gas atmosphere used, allows one to accurately control the crystalline phase and shape of the resulting nanostructures. Inert (N2), oxidizing (O2), or reducing (CO, H2) gases were used, leading to different morphologies and crystalline structures in a high yield, highly reproducible fabrication process.

  7. Gastropod seed dispersal: an invasive slug destroys far more seeds in its gut than native gastropods.

    Science.gov (United States)

    Blattmann, Tamara; Boch, Steffen; Türke, Manfred; Knop, Eva

    2013-01-01

    Seed dispersal is one of the most important mechanisms shaping biodiversity, and animals are one of the key dispersal vectors. Animal seed dispersal can directly or indirectly be altered by invasive organisms through the establishment of new or the disruption of existing seed dispersal interactions. So far it is known for a few gastropod species that they ingest and defecate viable plant seeds and consequently act as seed dispersers, referred to as gastropodochory. In a multi-species experiment, consisting of five different plant species and four different gastropod species, we tested with a fully crossed design whether gastropodochory is a general mechanism across native gastropod species, and whether it is altered by the invasive alien slug species Arion lusitanicus. Specifically, we hypothesized that a) native gastropod species consume the seeds from all tested plant species in equal numbers (have no preference), b) the voracious invasive alien slug A. lusitanicus--similarly to its herbivore behaviour--consumes a higher amount of seeds than native gastropods, and that c) seed viability is equal among different gastropod species after gut passage. As expected all tested gastropod species consumed all tested plant species. Against our expectation there was a difference in the amount of consumed seeds, with the largest and native mollusk Helix pomatia consuming most seeds, followed by the invasive slug and the other gastropods. Seed damage and germination rates did not differ after gut passage through different native species, but seed damage was significantly higher after gut passage through the invasive slug A. lusitanicus, and their germination rates were significantly reduced.

  8. Predation by carabid beetles (Coleoptera, Carabidae) on the invasive Iberian slug Arion lusitanicus

    OpenAIRE

    Hatteland, Bjørn Arild

    2010-01-01

    Predator-prey and host-parasite interactions are essential in understanding the population dynamics of any species, including pest species. In fact, integrated pest management that incorporates biological control requires a thorough understanding of the ecology of the pest and their interactions with natural enemies. The Iberian slug Arion lusitanicus has been spread from southern Europe to many parts of northern Europe, and has become a pest species in gardens, horticulture an...

  9. Liquid-liquid Slug Flow in a Microchannel Reactor and its Mass Transfer Properties - A Review

    Directory of Open Access Journals (Sweden)

    Rahul Antony

    2014-10-01

    Full Text Available Mass transfer is a basic phenomenon behind many processes like reaction, absorption, extraction etc. Mass transfer plays a significant role in microfluidic systems where the chemical / biological process systems are shrinkened down to a micro scale. Micro reactor system, with its high compatibility and performance, gains a wide interest among the researchers in the recent years. Micro structured reac-tors holds advantages over the conventional types in chemical processes. The significance of micro re-actor not limited to its scalability but to energy efficiency, on-site / on-demand production, reliability, safety, highly controlled outputs, etc. Liquid-liquid two phase reaction in a microreactor system is highly demandable when both reactants are liquids or when air medium cannot be suitable. This arti-cle overviews various liquid-liquid flow regimes in a microchannel. Discussions on the hydrodynamics of flow in micro scale are made. Considering the importance of mass transfer in liquid-liquid systems and the advantage of slug regime over other regimes, the article focuses especially on the mass trans-fer between two liquid phases in slug flow and the details of experimental studies carried out in this area. The advantages of slug flow over other flow regimes in micro structured reactor applications are showcased. © 2014 BCREC UNDIP. All rights reservedReceived: 31st May 2014; Revised: 6th August 2014; Accepted: 14th August 2014How to Cite: Antony, R., Giri Nandagopal, M.S., Sreekumar, N., Rangabhashiyam, S., Selvaraju, N. (2014. Liquid-liquid Slug Flow in a Microchannel Reactor and its Mass Transfer Properties - A Review. Bulletin of Chemical Reaction Engineering & Catalysis,9(3: 207-223. (doi:10.9767/bcrec.9.3.6977.207-223Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.3.6977.207-223

  10. Transmissivity and storage coefficient estimates from slug tests, Naval Air Warfare Center, West Trenton, New Jersey

    Science.gov (United States)

    Fiore, Alex R.

    2014-01-01

    Slug tests were conducted on 56 observation wells open to bedrock at the former Naval Air Warfare Center (NAWC) in West Trenton, New Jersey. Aquifer transmissivity (T) and storage coefficient (S) values for most wells were estimated from slug-test data using the Cooper-Bredehoeft-Papadopulos method. Test data from three wells exhibited fast, underdamped water-level responses and were analyzed with the Butler high-K method. The range of T at NAWC was approximately 0.07 to 10,000 square feet per day. At 11 wells, water levels did not change measurably after 20 minutes following slug insertion; transmissivity at these 11 wells was estimated to be less than 0.07 square feet per day. The range of S was approximately 10-10 to 0.01, the mode being 10-10. Water-level responses for tests at three wells fit poorly to the type curves of both methods, indicating that these methods were not appropriate for adequately estimating T and S from those data.

  11. Interfacial area, velocity and void fraction in two-phase slug flow

    Energy Technology Data Exchange (ETDEWEB)

    Kojasoy, G. [Univ. of Wisconsin, Milwaukee, WI (United States); Riznic, J.R. [Atomic Energy Control Board, Ottawa (Canada)

    1997-12-31

    The internal flow structure of air-water plug/slug flow in a 50.3 mm dia transparent pipeline has been experimentally investigated by using a four-sensor resistivity probe. Liquid and gas volumetric superficial velocities ranged from 0.55 to 2.20 m/s and 0.27 to 2.20 m/s, respectively, and area-averaged void fractions ranged from about 10 to 70%. The local distributions of void fractions, interfacial area concentration and interface velocity were measured. Contributions from small spherical bubbles and large elongated slug bubbles toward the total void fraction and interfacial area concentration were differentiated. It was observed that the small bubble void contribution to the overall void fraction was small indicating that the large slug bubble void fraction was a dominant factor in determining the total void fraction. However, the small bubble interfacial area contribution was significant in the lower and upper portions of the pipe cross sections.

  12. Prediction of Polymer Flooding Performance with an Artificial Neural Network: A Two-Polymer-Slug Case

    Directory of Open Access Journals (Sweden)

    Jestril Ebaga-Ololo

    2017-07-01

    Full Text Available Many previous contributions to methods of forecasting the performance of polymer flooding using artificial neural networks (ANNs have been made by numerous researchers previously. In most of those forecasting cases, only a single polymer slug was employed to meet the objective of the study. The intent of this manuscript is to propose an efficient recovery factor prediction tool at different injection stages of two polymer slugs during polymer flooding using an ANN. In this regard, a back-propagation algorithm was coupled with six input parameters to predict three output parameters via a hidden layer composed of 10 neurons. Evaluation of the ANN model performance was made with multiple linear regression. With an acceptable correlation coefficient, the proposed ANN tool was able to predict the recovery factor with errors of <1%. In addition, to understand the influence of each parameter on the output parameters, a sensitivity analysis was applied to the input parameters. The results showed less impact from the second polymer concentration, owing to changes in permeability after the injection of the first polymer slug.

  13. Reverse water-level change during interference slug tests in fractured rock

    Science.gov (United States)

    Slack, Trever Z.; Murdoch, Lawrence C.; Germanovich, Leonid N.; Hisz, David B.

    2013-03-01

    Reverse water-level responses in monitoring wells are widely known during pumping tests, where they are recognized as the Noordbergum or Rhade effects, and a similar response was observed in many of the 100+ interference slug tests conducted at a well field near Clemson, South Carolina. The reverse water-level effect is characterized by a drop in pressure head by 1 cm to several centimeters and it occurs in the first 10-100 s of the test. The reverse response is followed by a rise and fall of pressure head that is typical of slug-in tests. The reverse water-level response is highly repeatable, and it increases when the pressure used to create the slug test is increased. A conceptual model recognizes that opening displacement of the fracture wall can cause a pressure drop, even when the pressure increases in the wellbore. The conceptual model is supported by a closed-form, analytical solution and a numerical model that couple fluid pressure and deformation in a fracture. Characteristics of the reverse water-level response are sensitive to properties of the fracture system and enveloping formation. Parameter estimation methods can be used to invert theoretical analyses and use the reverse response to improve the characterization of fractured rock aquifers.

  14. Gas slug rise in open versus plugged basaltic conduits: the transition from Strombolian to sustained volcanic eruptions

    Science.gov (United States)

    Llewellin, Ed; Mathias, Simon; Del Bello, Elisabetta; Lane, Steve; Taddeucci, Jacopo

    2010-05-01

    Strombolian eruptions are characterized by low-energy explosive activity, which may repeat, at fairly regular intervals, for long periods of time. Explosions at the vent are thought to result from the arrival of discrete slugs of magmatic gas that have risen through the magmatic plumbing system. We develop a one dimensional, analytical model of gas slug rise in a volcanic conduit which we use to investigate the controls on the dynamics of Strombolian eruptions. We consider a partially-filled, cylindrical conduit containing degassed magma, that is initially in magma-static equilibrium with a constant pressure magma reservoir at depth. We introduce a slug of gas at the base of the conduit and consider the temporal evolution of the pressure distribution in the conduit, and the motion of the magma above and below the slug, as the slug rises, decompresses, and expands isothermally. We validate our model against published data for gas slugs rising and decompressing in a vertical pipe [James et al., 2008, Geological Society of London, Special Publications 307, 147-167] by imposing the condition of zero magma-flux at the base of the conduit, and constant pressure at the top; we find excellent agreement. If we impose the more geologically-sound condition of constant pressure at the base of the conduit, we can consider two scenarios of volcanological relevance: 1) Vent plugged with cooler, more-viscous magma. In this case, as the slug rises and expands beneath the plug, it pushes the degassed magma below it down the conduit, consequently, magma re-enters the chamber from the base of the conduit. The slug reaches the viscous plug at the top of the conduit with a significant over-pressure; this may be sufficient to disrupt the plug, causing a Strombolian explosion, or the gas may percolate away. Fresh magma then moves up from the chamber, into the conduit to restore magma-static equilibrium. 2) Open vent. As the slug rises and expands, the volume of magma held in the falling

  15. Predation by beetles (Carabidae, Staphylinidae) on eggs and juveniles of the Iberian slug Arion lusitanicus in the laboratory.

    Science.gov (United States)

    Hatteland, B A; Grutle, K; Mong, C E; Skartveit, J; Symondson, W O C; Solhøy, T

    2010-10-01

    Arion lusitanicus has become a major pest species in western Norway in the last few years. This species originates from southern Europe but has been spread by humans over large parts of central and northern Europe during recent decades. Slugs have traditionally been controlled by the use of molluscicides; but, as these may have serious ecological side effects, biological control of slugs is highly desirable. Potential biological control agents include nematodes, gastropods and arthropods. In laboratory experiments, we tested whether five common predator beetles would feed on eggs and juveniles of A. lusitanicus. The species Carabus nemoralis, Nebria brevicollis, Pterostichus melanarius and Pterostichus niger (Carabidae) as well as Staphylinus erythropterus (Staphylinidae) were tested, of which only P. melanarius has been tested on A. lusitanicus previously. Nebria brevicollis did not feed on slug eggs or newly hatched slugs, but the remaining four species all killed and ate a large proportion of the eggs and hatchlings offered. Both P. melanarius and P. niger also destroyed A. lusitanicus eggs and hatchlings under conditions emulating those in the field. Prey size choice experiments were conducted by feeding C. nemoralis, P. niger and S. erythropterus on different sizes of A. lusitanicus. Carabus nemoralis was also given a choice between two slug species, A. lusitanicus and Deroceras reticulatum. A significant preference for slugs smaller than one gram was evident for C. nemoralis, while the other beetles struggled much more to overcome the mucus of juvenile slugs. No significant preference was found between A. lusitanicus and D. reticulatum as prey for C. nemoralis. We also discuss the feasibility of biological control of A. lusitanicus using beetle predators.

  16. Expression and localization of transcription factors SNAIL and SLUG in mouse ovaries and pre-implantation embryos.

    Science.gov (United States)

    Guo, Cui; Meng, Xiaoqian; Bai, Jing; Chen, Cheng; Liu, Tao; Liu, Shuzhen; Zhang, Cong; Li, Wei-Ping

    2014-11-01

    SNAIL and SLUG are zinc-finger transcription factors that participate in the regulation of cell division, cell survival, mesoderm formation and epithelial-to-mesenchymal transition. We investigate the expression of SNAIL and SLUG during follicular maturation, ovulation and luteinization in the ovaries of both neonatal mice and gonadotropin-induced immature mice. Furthermore, we examine the expression and localization of these transcription factors during early embryonic cleavage. Our data demonstrate that both SNAIL and SLUG are present in the epithelial cells of the ovarian surface in immature mice. SNAIL is first evident in the interstitial cells and theca cells by postnatal day (PD) 6 and then appears in the oocytes by PD 8, remaining at a constant expression level for all stages studied thereafter. SLUG is expressed in oocytes as early as PD 1. Its expression also increases with the development of the follicles in theca and interstitial cells but not in granulosa cells. In gonadotropin-induced immature mice, both SNAIL and SLUG are expressed in the corpora lutea. During early embryo cleavage, SNAIL occurs in the nucleus and cytoplasm of the majority of the embryo, excluding the nucleolus from the germinal vesicle breakdown (GVBD) to the 8-cell stage and is then localized in the cytoplasm during the morula stage and in the nucleus during the blastocyst stage. SLUG has an identical expression pattern as SNAIL from GVBD until the morula stage, except that it is localized in the cytoplasm during the blastocyst stage. Taken together, these different localization patterns suggest that SNAIL and SLUG probably play important roles during follicular development, luteinization and early embryonic development.

  17. MULTIPHASE DROPLET/SLUG BREAK-UP MECHANISM IN MICROFLUIDIC T-JUNCTIONS AT VARIOUS WEBER NUMBERS

    Directory of Open Access Journals (Sweden)

    Wan Leng (Dawn Leow

    2011-10-01

    Full Text Available Normal 0 false false false EN-MY X-NONE X-NONE The formation of immiscible liquid droplets, or slugs, in microchannels features the advantages of volume control and mixing enhancement over single-phase microflows. Although the applications of droplet-based microfluidics have been widely demonstrated, the fundamental physics governing droplet break-up remains an area of active research. This study defines an effective Weber (Weeff number that characterizes the interplay of interfacial tension, shear stress and channel pressure drop in driving slug formation in T-junction microchannel for a relative range of low, intermediate and high flow rates. The immiscible fluid system in this study consists of Tetradecane slug formation in Acetonitrile. The progressive deformation of slug interfaces during break-up events is observed. Experimental results indicate that, at a relatively low Weeff, clean slug break-up occurs at the intersection of the side and main channels. At intermediate Weeff, the connecting neck of the dispersed phase is stretched to a short and thin trail of laminar flow prior to breaking up a short distance downstream of the T-junction. At a relatively high Weeff, the connecting neck develops into a longer and thicker trail of laminar flow that breaks up further downstream of the main channel.

  18. Induction of Slug by Chronic Exposure to Single-Walled Carbon Nanotubes Promotes Tumor Formation and Metastasis.

    Science.gov (United States)

    Wang, Peng; Voronkova, Maria; Luanpitpong, Sudjit; He, Xiaoqing; Riedel, Heimo; Dinu, Cerasela Z; Wang, Liying; Rojanasakul, Yon

    2017-07-17

    Carbon nanotubes (CNTs) represent a major class of engineered nanomaterials that are being used in diverse fields. However, their use has increasingly become a concern because of their carcinogenic potential. Accumulating evidence has demonstrated that certain types of CNTs are carcinogenic or tumor-promoting in animal models. However, the underlying molecular and cellular mechanisms are unclear. Here, we report that chronic exposure to single-walled (SW) CNTs results in the induction of Slug, a key transcription factor that induces an epithelial-mesenchymal transition (EMT), in human lung epithelial cells. We show that SWCNT-induced Slug upregulation plays a critical role in the aggressive phenotype of SWCNT-exposed cells, which includes increased cell migration, invasion, and anchorage-independent cell growth. Our in vivo studies also show that SWCNT-induced Slug upregulation and EMT activation play a pivotal role in tumor formation and metastasis. Our findings illustrate a direct link between CNT-induced Slug upregulation, EMT activation, and tumor formation and metastasis, and they highlight the potential of CNT-induced Slug upregulation as a target for future risk assessment and prevention of CNT-associated diseases.

  19. A Study on the Optimization of Surfactants in the Main and Vice Slug in Weak Base ASP Flooding

    Directory of Open Access Journals (Sweden)

    Bin Huang

    2017-03-01

    Full Text Available In ASP (Alkali-Surfactant-Polymer flooding processes, surfactants help to enhance oil recovery by lowering the interfacial tension between the oil and water. However, due to the high cost of surfactants and the stability of the emulsion that varies with surfactant concentration, it is necessary to optimize the surfactant concentration in ASP flooding. In this study, we combined numerical simulation and physical experimental research to solve this problem. In order to screen for the optimal surfactant concentration in the main and vice slugs, CMG (Computer Measurement Group numerical simulation software was used to change the surfactant concentration in the injected compound system and the oil recovery factor and the recovery percent of reserves were compared. The physical experiments were also carried out with different surfactant concentrations and the results verified the simulation results. It shows that the recovery factor increases with the surfactant concentration. The optimal surfactant concentration in the main and vice slug are 0.3% and 0.15%, respectively. As for improving the recovery factor, it is more efficient to increase the mass fraction of the surfactant in the vice slug than in the main slug. It demonstrates that the amount of surfactant in the main slug plays a more important role in displacing oil from the formation.

  20. BMP4 promotes EMT and mesodermal commitment in human embryonic stem cells via SLUG and MSX2.

    Science.gov (United States)

    Richter, Anne; Valdimarsdottir, Lena; Hrafnkelsdottir, Helga Eyja; Runarsson, Johann Frimann; Omarsdottir, Arna Run; Ward-van Oostwaard, Dorien; Mummery, Christine; Valdimarsdottir, Gudrun

    2014-03-01

    Bone morphogenetic proteins (BMPs) initiate differentiation in human embryonic stem cells (hESCs) but the exact mechanisms have not been fully elucidated. We demonstrate here that SLUG and MSX2, transcription factors involved in epithelial-mesenchymal transitions, essential features of gastrulation in development and tumor progression, are important mediators of BMP4-induced differentiation in hESCs. Phosphorylated Smad1/5/8 colocalized with the SLUG protein at the edges of hESC colonies where differentiation takes place. The upregulation of the BMP target SLUG was direct as shown by the binding of phosphorylated Smad1/5/8 to its promoter, which interrupted the formation of adhesion proteins, resulting in migration. Knockdown of SLUG by short hairpin RNA blocked these changes, confirming an important role for SLUG in BMP-mediated mesodermal differentiation. Furthermore, BMP4-induced MSX2 expression leads to mesoderm formation and then preferential differentiation toward the cardiovascular lineage. © 2013 AlphaMed Press.

  1. Model-Free Predictive Anti-Slug Control of a Well-Pipeline-Riser

    Directory of Open Access Journals (Sweden)

    Christer Dalen

    2016-01-01

    Full Text Available Simplified linearized discrete time dynamic state space models are developed for a 3-phase well-pipeline-riser and tested together with a high fidelity dynamic model built in K-Spice and LedaFlow. In addition the Meglio pipeline-riser model is used as an example process. These models are developed from a subspace algorithm, i.e. Deterministic and Stochastic system identification and Realization (DSR, and implemented in a Model Predictive Controller (MPC for stabilizing the slugging regime. The MPC, LQR and PI control strategies are tested.

  2. Dependence of hydraulic conductivity estimates from slug tests on displacement depth

    Science.gov (United States)

    Sauter, M.; Brauchler, R.

    2009-12-01

    Slug tests are generally accepted as an efficient tool for the hydraulic characterisation of aquifers. They can readily be employed without major logistical efforts and allow in particular the characterisation of contaminated aquifers since there is no contaminated water that needs to be disposed of. They are especially suited for assessing low conductive rock formations, where pumping quickly has to be stopped because the wells dry up. In cases where a dense well network is available slug tests can provide detailed information about the spatial variability of hydraulic conductivity. Limitations are: a) the small volume of integration, b) problems of obtaining representative storage parameters, and c) a large number of effects, the data need to be corrected for, especially in highly conductive aquifers, e.g. inertia, skin effects etc.. During a characterisation study, performed in karstified rocks, it was observed that the hydraulic conductivities obtained from the slug test data depended on the depth of displacement, i.e. an increase in displacement from 2.5 m to 11 m resulted in a change of hydraulic conductivity by a factor of 10. This feature, which is attributed to the heterogeneous characteristics of the fracture / matrix system, has also been described by Streltsova (1988), who observed that whenever "the formation volume, influenced by the test is smaller than the representative formation volume required for fracture pattern replication". The following conceptual model explains this hydraulic behaviour. If the well is drilled within a compact matrix block, the hydraulic response of an aquifer section is mainly determined by the low matrix conductivity near the well. If however the well is connected to the fracture network, short tests will only excite the highly conductive fractures and the longer the duration of the test, the more the less conductive matrix will contribute to the test result. Therefore a systematic decrease in the hydraulic conductivity

  3. 3-D slug flow heat transfer analysis of coupled coolant cells in finite LMFBR bundles

    Energy Technology Data Exchange (ETDEWEB)

    Wong, C.N.; Wolf, L.

    1978-02-01

    A three-dimensional single region slug flow heat transfer analysis for finite LMFBR rod bundles using a classical analytical solution method has been performed. According to the isolated single cell analysis, the results show that the peripheral clad temperature variation as well as the thermal entrance length are strongly dependent upon the degree of irregularity displayed by various coolant geometries. Since under the present LMFBR conditions, fully-developed temperature fields may hardly be established in such characteristic rod bundle regions, a 3-D heat transfer analysis seems to be mandatory. This implies that the results of fully developed heat transfer analyses are by far too conservative.

  4. Introduced Terrestrial Species (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data represent predicted future potential distributions of terrestrial plants, animals, and pathogens non-native to the Middle-Atlantic region. These data are...

  5. BTBD7 silencing inhibited epithelial- mesenchymal transition (EMT) via regulating Slug expression in human salivary adenoid cystic carcinoma.

    Science.gov (United States)

    Yang, Liu; Wang, Tiejun; Zhang, Jun; Wang, Xuxia

    2017-12-06

    Epithelial-mesenchymal transition (EMT) is a complicated process that has been implicated in cancer progression and metastasis as well as the formation of many tissues and organs. BTB/POZ domain-containing protein 7 (BTBD7) is reported to regulate transcriptional factors and involved in the process of invasion and metastasis of some malignant tumors. Additionally, our preliminary studies have confirmed that BTBD7 expression was significantly correlated with Slug expression and poor prognosis of primary salivary adenoid cystic carcinoma (SACC). On this basis, this study further investigated function of BTBD7 in the invasion and metastasis of SACC in vitro, which may be a possible target of gene therapy in the future. The expression of BTBD7 and Slug were both examined in SACC-LM and SACC-83 cell lines by immunofluorescence staining. High invasive SACC-LM cells were transfected with BTBD7 siRNA and the expression levels of BTBD7 and Slug were detected in both gene and protein levels by qRT-PCR and western blot analysis. Assays were performed to survey cell migration, invasion and proliferation capabilities with BTBD7 silencing. BTBD7 and Slug proteins were detected in SACC-LM and SACC-83 cell lines. BTBD7 silencing down-regulated the expression of Slug and MMP9 meanwhile up-regulated the expression of E-cadherin in SACC-LM cells, the migration and invasion abilities of cells were obviously suppressed but with no influence on cell proliferation. BTBD7 silencing inhibited EMT through regulation of Slug expression in SACC-LM cells and might act as a potential molecular target for gene therapy of SACC.

  6. Pellino-1 promotes lung carcinogenesis via the stabilization of Slug and Snail through K63-mediated polyubiquitination.

    Science.gov (United States)

    Jeon, Yoon Kyung; Kim, Chung Kwon; Hwang, Kyung Rim; Park, Hye-Young; Koh, Jaemoon; Chung, Doo Hyun; Lee, Chang-Woo; Ha, Geun-Hyoung

    2017-03-01

    Pellino-1 is an E3 ubiquitin ligase acting as a critical mediator for a variety of immune receptor signaling pathways, including Toll-like receptors, interleukin-1 receptor and T-cell receptors. We recently showed that the Pellino-1-transgenic (Tg) mice developed multiple tumors with different subtypes in hematolymphoid and solid organs. However, the molecular mechanism underlying the oncogenic role of Pellino-1 in solid tumors remains unknown. Pellino-1-Tg mice developed adenocarcinoma in the lungs, and Pellino-1 expression was higher in human lung adenocarcinoma cell lines compared with non-neoplastic bronchial epithelial cell lines. Pellino-1 overexpression increased the cell proliferation, survival, colony formation, invasion and migration of lung adenocarcinoma cells, whereas Pellino-1 knock-down showed the opposite effect. Pellino-1 overexpression activated PI3K/Akt and ERK signaling pathways and elicited an epithelial-mesenchymal transition (EMT) phenotype of lung adenocarcinoma cells. Pellino-1-mediated EMT was demonstrated through morphology, the upregulation of Vimentin, Slug and Snail expression and the downregulation of E-cadherin and β-catenin expression. Notably, Pellino-1 had a direct effect on the overexpression of Snail and Slug through Lys63-mediated polyubiquitination and the subsequent stabilization of these proteins. Pellino-1 expression level was significantly correlated with Snail and Slug expression in human lung adenocarcinoma tissues, and lung tumors from Pellino-1-Tg mice showed Snail and Slug overexpression. The Pellino-1-mediated increase in the migration of lung adenocarcinoma cells was mediated by Snail and Slug expression. Taken together, these results show that Pellino-1 contributes to lung tumorigenesis by inducing overexpression of Snail and Slug and promoting EMT. Pellino-1 might be a potential therapeutic target for lung cancer.

  7. 微通道内气-液弹状流动及传质特性研究进展 (Review on flow and mass transfer characteristics of gas-liquid slug flow in microchannels)

    NARCIS (Netherlands)

    Yao, Chaoqun; Yue, Jun; Zhao, Yuchao; Chen, Guangwen; Yuan, Quan

    2015-01-01

    Gas-liquid slug flow (also termed as Taylor flow) is a flow pattern characterized by the alternate movement of elongated bubbles and liquid slugs. Gas-liquid slug flow operation in microchannels has been found important implications in the enhancement of gas-liquid reactions due to its advantages

  8. Wire-mesh and ultrasound techniques applied for the characterization of gas-liquid slug flow

    Energy Technology Data Exchange (ETDEWEB)

    Ofuchi, Cesar Y.; Sieczkowski, Wytila Chagas; Neves Junior, Flavio; Arruda, Lucia V.R.; Morales, Rigoberto E.M.; Amaral, Carlos E.F.; Silva, Marco J. da [Federal University of Technology of Parana, Curitiba, PR (Brazil)], e-mails: ofuchi@utfpr.edu.br, wytila@utfpr.edu.br, neves@utfpr.edu.br, lvrarruda@utfpr.edu.br, rmorales@utfpr.edu.br, camaral@utfpr.edu.br, mdasilva@utfpr.edu.br

    2010-07-01

    Gas-liquid two-phase flows are found in a broad range of industrial applications, such as chemical, petrochemical and nuclear industries and quite often determine the efficiency and safety of process and plants. Several experimental techniques have been proposed and applied to measure and quantify two-phase flows so far. In this experimental study the wire-mesh sensor and an ultrasound technique are used and comparatively evaluated to study two-phase slug flows in horizontal pipes. The wire-mesh is an imaging technique and thus appropriated for scientific studies while ultrasound-based technique is robust and non-intrusive and hence well suited for industrial applications. Based on the measured raw data it is possible to extract some specific slug flow parameters of interest such as mean void fraction and characteristic frequency. The experiments were performed in the Thermal Sciences Laboratory (LACIT) at UTFPR, Brazil, in which an experimental two-phase flow loop is available. The experimental flow loop comprises a horizontal acrylic pipe of 26 mm diameter and 9 m length. Water and air were used to produce the two phase flow under controlled conditions. The results show good agreement between the techniques. (author)

  9. CFD Analysis of a Slug Mixing Experiment Conducted on a VVER-1000 Model

    Directory of Open Access Journals (Sweden)

    F. Moretti

    2009-01-01

    Full Text Available A commercial CFD code was applied, for validation purposes, to the simulation of a slug mixing experiment carried out at OKB “Gidropress” scaled facility in the framework of EC TACIS project R2.02/02: “Development of safety analysis capabilities for VVER-1000 transients involving spatial variations of coolant properties (temperature or boron concentration at core inlet.” Such experimental model reproduces a VVER-1000 nuclear reactor and is aimed at investigating the in-vessel mixing phenomena. The addressed experiment involves the start-up of one of the four reactor coolant pumps (the other three remaining idle, and the presence of a tracer slug on the starting loop, which is thus transported to the reactor pressure vessel where it mixes with the clear water. Such conditions may occur in a boron dilution scenario, hence the relevance of the addressed phenomena for nuclear reactor safety. Both a pretest and a posttest CFD simulations of the mentioned experiment were performed, which differ in the definition of the boundary conditions (based either on nominal quantities or on measured quantities, resp.. The numerical results are qualitatively and quantitatively analyzed and compared against the measured data in terms of space and time tracer distribution at the core inlet. The improvement of the results due to the optimization of the boundary conditions is evidenced, and a quantification of the simulation accuracy is proposed.

  10. Slugs control methods (Deroceras sp. Müller in lettuce and broccoli crops

    Directory of Open Access Journals (Sweden)

    Salazar G. Claudia

    2011-08-01

    Full Text Available

    At the Botana experimental farm of Universidad de Narino, the effect of different management practices of slugs was evaluated, using a randomized block design with five treatments (beer traps, milk traps, sisal bags, metaldehyde, and a control and six repetitions. The evaluated variables were: captured individuals, affected plants and damage index that were estimated by analysis of variance and Tukey comparison tests. The results show highly significant differences between treatments in different phenological crops stages, the most effective were the metaldehyde and the beer trap with a caught individual number of 89 for lettuce and 126 for broccoli, being the treatments with lower percentages of affected plants. The damage index was evaluated based on percentages and proposed scales to observed crops damage, considering that the treatments described above stood out with mild damage index. This allows involved the beer treatment in an integrated management program for slugs as an alternative for reducing the pest population.

  11. A method for the estimation of dual transmissivities from slug tests

    Science.gov (United States)

    Wolny, Filip; Marciniak, Marek; Kaczmarek, Mariusz

    2017-11-01

    Aquifer homogeneity is usually assumed when interpreting the results of pumping and slug tests, although aquifers are essentially heterogeneous. The aim of this study is to present a method of determining the transmissivities of dual-permeability water-bearing formations based on slug tests such as the pressure-induced permeability test. A bi-exponential rate-of-rise curve is typically observed during many of these tests conducted in heterogeneous formations. The work involved analyzing curves deviating from the exponential rise recorded at the Belchatow Lignite Mine in central Poland, where a significant number of permeability tests have been conducted. In most cases, bi-exponential movement was observed in piezometers with a screen installed in layered sediments, each with a different hydraulic conductivity, or in fissured rock. The possibility to identify the flow properties of these geological formations was analyzed. For each piezometer installed in such formations, a set of two transmissivity values was calculated piecewise based on the interpretation algorithm of the pressure-induced permeability test—one value for the first (steeper) part of the obtained rate-of-rise curve, and a second value for the latter part of the curve. The results of transmissivity estimation for each piezometer are shown. The discussion presents the limitations of the interpretational method and suggests future modeling plans.

  12. A Review of the Multilevel Slug Test for Characterizing Aquifer Heterogeneity

    Directory of Open Access Journals (Sweden)

    Chia-Shyun Chen

    2012-01-01

    Full Text Available All aquifers are heterogeneous to a certain degree. The spatial distribution of hydraulic conductivity K(x, y, z, or aquifer heterogeneity, significantly influences the groundwater flow movement and associated solute transport. Of particular importance in designing an in-situ remediation plan is a knowledge of low-K layers because they are less accessible to remedial agents and form a bottleneck in remediation. The characterization of aquifer heterogeneity is essential to the solution of many practical and scientific groundwater problems. This article reviews the field technique using the multilevel slug test (MLST, which determines a series of K estimates at depths of interest in a well by making use of a double-packer system. The K(z obtained manifests the vertical variation of hydraulic conductivity in the vicinity of the test well, and the combination of K(z from different wells gives rise to a three-dimensional description of K(x, y, z. The MLST response is rather sensitive to hydraulic conductivity variation; e.g., it is oscillatory for highly permeable conditions (K > 5 × 10-4 m s-1 and a nonoscillatory for K < 5 × 10-4 m s-1. In this article we discuss the instrumentation of the double-packer system, the implementation of the depth-specific slug test, the data analysis methods for a spectrum of response characteristics usually observed in the field, and field applications of the MLST.

  13. Banana Slug

    Science.gov (United States)

    First, Lucas

    2009-01-01

    Everyone insists that a person should go to a college that is right for him/her, somewhere that fits who he/she is, a place where a they belong. There are more than 4,000 colleges and universities in this country; how will a person find the one that is right for them? In this article, the author suggests that one should follow the mascot when…

  14. Plastid-bearing sea slugs fix CO2 in the light but do not require photosynthesis to survive

    NARCIS (Netherlands)

    G. Christa (Gregor); V. Zimorski (Verena); C. Woehle (Christian); A.G.M. Tielens (Aloysius); H. Wägele (Heike); W. Martin (William); D.B. Gould (Douglas )

    2013-01-01

    textabstractSeveral sacoglossan sea slugs (Plakobranchoidea) feed upon plastids of large unicellular algae. Four species-called long-term retention (LtR) species-are known to sequester ingested plastids within specialized cells of the digestive gland. There, the stolen plastids (kleptoplasts) remain

  15. Plastid-bearing sea slugs fix CO2 in the light but do not require photosynthesis to survive

    NARCIS (Netherlands)

    Christa, Gregor; Zimorski, Verena; Woehle, Christian; Tielens, Aloysius G M; Wägele, Heike; Martin, William F; Gould, Sven B

    2014-01-01

    Several sacoglossan sea slugs (Plakobranchoidea) feed upon plastids of large unicellular algae. Four species--called long-term retention (LtR) species--are known to sequester ingested plastids within specialized cells of the digestive gland. There, the stolen plastids (kleptoplasts) remain

  16. Terrestrial and extraterrestrial fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Heymann, D.; Jenneskens, L.W.; Jehlicka, J; Koper, C.; Vlietstra, E. [Rice Univ, Houston, TX (United States). Dept. of Earth Science

    2003-07-01

    This paper reviews reports of occurrences of fullerenes in circumstellar media, interstellar media, meteorites, interplanetary dust particles (IDPs), lunar rocks, hard terrestrial rocks from Shunga (Russia), Sudbury (Canada) and Mitov (Czech Republic), coal, terrestrial sediments from the Cretaceous-Tertiary-Boundary and Pennian-Triassic-Boundary, fulgurite, ink sticks, dinosaur eggs, and a tree char. The occurrences are discussed in the context of known and postulated processes of fullerene formation, including the suggestion that some natural fullerenes might have formed from biological (algal) remains.

  17. The use of a low-cost gas-liquid flow meter to monitor severe slugging

    DEFF Research Database (Denmark)

    Andreussi, Paolo; Bonizzi, Marco; Ciandri, Paolo

    2017-01-01

    of a multiphase orifice and the pressure drops of the gas-liquid mixture flowing in a vertical section of the pipe. Liquid and gas flow rates have been determined by means of semi-empirical equations developed for the specific set of flow parameters (geometry, flow rates, physical properties) adopted in a series...... of laboratory tests conducted in the Multiphase Flow Laboratory of TEA Sistemi. The transient behavior of the flow system, including the orifice, has also been predicted by means of a 1-D flow simulator [2]. The results of these simulations agree well with the experimental readings, thus providing a powerful......A very simple, low-cost gas-liquid flow meter that only employs conventional field instrumentation has been used to monitor severe slugging occurring at the exit of a vertical pipe. This meter was originally developed for conventional oil field applications [1] and is based on the readings...

  18. Standard Test Method for Measuring Heat-Transfer Rate Using a Thermal Capacitance (Slug) Calorimeter

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method describes the measurement of heat transfer rate using a thermal capacitance-type calorimeter which assumes one-dimensional heat conduction into a cylindrical piece of material (slug) with known physical properties. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. Note 1—For information see Test Methods E 285, E 422, E 458, E 459, and E 511.

  19. Sea slugs, subliminal pictures and vegetative state patients: Boundaries of consciousness in classical conditioning.

    Directory of Open Access Journals (Sweden)

    Tristan A Bekinschtein

    2011-12-01

    Full Text Available Classical (trace conditioning is a specific variant of associative learning in which a neutral stimulus leads to the subsequent prediction of an emotionally charged or noxious stimulus after a temporal gap. When conditioning is concurrent with a distraction task, only participants who can report the relationship (the contingency between stimuli explicitly show associative learning. This suggests that consciousness is a prerequisite for trace conditioning. We review and question three main controversies concerning this view. Firstly, virtually all animals, even invertebrate sea slugs, show this type of learning; secondly, unconsciously perceived stimuli may elicit trace conditioning; and thirdly, some vegetative state patients show trace learning. We discuss and analyze these seemingly contradictory arguments to find the theoretical boundaries of consciousness in classical conditioning. We conclude that trace conditioning remains one of the best measures to test conscious processing in the absence of explicit reports.

  20. Epidemiological features of snail and slug bait poisoning in dogs and cats.

    Science.gov (United States)

    Studdert, V P

    1985-08-01

    Snail and slug baits were the most common cause of poisoning in dogs and cats in a survey of 34 veterinary practices. During a 7-month period, 280 dogs and 12 cats were poisoned by metaldehyde (57%) or methiocarb (43%) containing baits with case fatality rates of 8.1% and 9.1% in dogs and 16.7% and 50% in cats, respectively. The ages of poisoned dogs ranged from 2 months to 17 years and cats from 3 months to 5 years. There was no decrease in frequency of poisoning or case fatality rate demonstrated with increasing body size in dogs. Poisoning was most frequent in the month of October. Baits were eaten off the ground or obtained from storage areas, often despite a variety of preventive measures. It is suggested that these products should be reformulated to make them less attractive to domestic pets.

  1. A user interface for the Kansas Geological Survey slug test model.

    Science.gov (United States)

    Esling, Steven P; Keller, John E

    2009-01-01

    The Kansas Geological Survey (KGS) developed a semianalytical solution for slug tests that incorporates the effects of partial penetration, anisotropy, and the presence of variable conductivity well skins. The solution can simulate either confined or unconfined conditions. The original model, written in FORTRAN, has a text-based interface with rigid input requirements and limited output options. We re-created the main routine for the KGS model as a Visual Basic macro that runs in most versions of Microsoft Excel and built a simple-to-use Excel spreadsheet interface that automatically displays the graphical results of the test. A comparison of the output from the original FORTRAN code to that of the new Excel spreadsheet version for three cases produced identical results.

  2. Spatial variability of hydraulic conductivity of an unconfined sandy aquifer determined by a mini slug test

    DEFF Research Database (Denmark)

    Bjerg, Poul Løgstrup; Hinsby, Klaus; Christensen, Thomas Højlund

    1992-01-01

    The spatial variability of the hydraulic conductivity in a sandy aquifer has been determined by a mini slug test method. The hydraulic conductivity (K) of the aquifer has a geometric mean of 5.05 × 10−4 m s−1, and an overall variance of 1n K equal to 0.37 which corresponds quite well to the results...... obtained by two large scale tracer experiments performed in the aquifer. A geological model of the aquifer based on 31 sediment cores, proposed three hydrogeological layers in the aquifer concurrent with the vertical variations observed with respect to hydraulic conductivity. The horizontal correlation...... length of the hydraulic conductivity has been determined for each of the three hydrogeological layers and is found to be small (1–2.5 m). The asymptotic longitudinal dispersivity of the aquifer has been estimated from the variance in hydraulic conductivity and the horizontal correlation length...

  3. The terrestrial silica pump.

    Directory of Open Access Journals (Sweden)

    Joanna C Carey

    Full Text Available Silicon (Si cycling controls atmospheric CO(2 concentrations and thus, the global climate, through three well-recognized means: chemical weathering of mineral silicates, occlusion of carbon (C to soil phytoliths, and the oceanic biological Si pump. In the latter, oceanic diatoms directly sequester 25.8 Gton C yr(-1, accounting for 43% of the total oceanic net primary production (NPP. However, another important link between C and Si cycling remains largely ignored, specifically the role of Si in terrestrial NPP. Here we show that 55% of terrestrial NPP (33 Gton C yr(-1 is due to active Si-accumulating vegetation, on par with the amount of C sequestered annually via marine diatoms. Our results suggest that similar to oceanic diatoms, the biological Si cycle of land plants also controls atmospheric CO(2 levels. In addition, we provide the first estimates of Si fixed in terrestrial vegetation by major global biome type, highlighting the ecosystems of most dynamic Si fixation. Projected global land use change will convert forests to agricultural lands, increasing the fixation of Si by land plants, and the magnitude of the terrestrial Si pump.

  4. Batteries for terrestrial applications

    Energy Technology Data Exchange (ETDEWEB)

    Kulin, T.M.

    1998-07-01

    Extensive research has been conducted in the design and manufacture of very long life vented and sealed maintenance free nickel-cadmium aircraft batteries. These batteries have also been used in a number of terrestrial applications with good success. This study presents an overview of the Ni-Cd chemistry and technology as well as detailed analysis of the advantages and disadvantages of the Ni-Cd couple for terrestrial applications. The performance characteristics of both sealed and vented Ni-Cd's are presented. Various charge algorithms are examined and evaluated for effectiveness and ease of implementation. Hardware requirements for charging are also presented and evaluated. The discharge characteristics of vented and sealed Ni-Cd's are presented and compared to other battery chemistries. The performance of Ni-Cd's under extreme environmental conditions is also compared to other battery chemistries. The history of various terrestrial applications is reviewed and some of the lessons learned are presented. Applications discussed include the NASA Middeck Payload Battery, Raytheon Aegis Missile System Battery, THAAD Launcher battery, and the Titan IV battery. The suitability of the Ni-Cd chemistry for other terrestrial applications such as electric vehicles and Uninterruptible Power Supply is discussed.

  5. Terrestrial planet formation.

    Science.gov (United States)

    Righter, K; O'Brien, D P

    2011-11-29

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids.

  6. Automatic detection of ''bore slug'' in tubes; Detection automatique des manques de metal internes sur tubes

    Energy Technology Data Exchange (ETDEWEB)

    Bisiaux, B.; Deutsch, S.; Tailleux, O.; Mette, F. [CEV Vallourec, Aulnoye (France)

    2001-07-01

    During the tube manufacturing for the petroleum industry, the lacks of internal metal (called Bore Slug) can be created during the hot rolling. These large defects are not good detected by the classic UT and by the wall thickness measurement. That's why VALLOUREC developed an automatic UT device which works by transmission. Nevertheless, this system is too little selective and can cause no doubtful pipes (tubes good detected bad). We adapted a Bore Slug control system on the VMOG UK RP20 at the end of August. The results are rather good and showed a good detection of the Bore Slug and very little no doubtful pipes. (authors)

  7. Slug-tests in PP- and PVP-holes at Olkiluoto in 2005

    Energy Technology Data Exchange (ETDEWEB)

    Tammisto, E. [Poeyry Environment Oy, Vantaa (Finland); Lehtinen, A. [Posiva Oy, Helsinki (Finland)

    2006-11-15

    As part of the program for the final disposal of the nuclear fuel waste, Posiva Oy investigates the hydrological conditions at the Olkiluoto island. The hydraulic conductivity in the shallow holes OL-PP5, OL-PP9, OL-PP39, OL-PVP4A, OLPVP4B, OL-PVP13, OL-PVP14, OL-PVP17, OL-PVP18A, OL-PVP18B, OL-PVP19 and OL-PVP20 was measured in summer 2005. The length of PP-holes varies between 12 and 15 m, and the test sections (1 m) are located in the bedrock. PVP-tubes have a length up to 17 m, and the test sections (1 - 4 m) are located in the overburden. The measurements were done using the slug-test technique. In the slug-test, the hydraulic head in the borehole is abruptly changed either by pouring water into the borehole or by lowering the pressure sensor. The conductivity is interpreted based on the recovery of the water level. This report presents the field measurements and their interpretation. The interpretation has been done using the Hvorslev's method, and for reference conductivity has also been calculated according to Thiem's equation. According to the results, hydraulic conductivity in PP-holes ranges from 10{sup -9} m/s to 10{sup -5} m/s and in PVP-tubes from 10{sup -7} m/s to 10{sup -4} m/s. The range is similar as observed in measurements of years 2002 and 2004. Expect few test sections, the results from 2005 are close to ones measured in the same sections in 2002 and 2004. The results agree also with hydraulic conductivity interpreted from the pre-pumping done in connection with the groundwater sampling. (orig.)

  8. Slug-tests in PP- and PVP-holes at Olkiluoto in 2004

    Energy Technology Data Exchange (ETDEWEB)

    Tammisto, E.; Hellae, P. [JP-Fintact Oy, Vantaa (Finland); Lahdenperae, J. [Posiva Oy, Helsinki (Finland)

    2005-12-15

    As part of the program for the final disposal of the nuclear fuel waste, Posiva Oy investigates the hydrological conditions at the Olkiluoto island. The hydraulic conductivity in the shallow holes PP2, PP38 and PP39 were measured in July 2004 and PVP4A, PVP4B and PVP14 in June 2004, PVP11, PVP12 and PVP13 in December 2004 and PVP2 in January 2005. The length of PP-holes varies between 13 and 24 m and the measured sections (1 m) are located in the bedrock. PVP-holes have a length up to 10 m and the measured sections (2 m) are located in the overburden. The measurements were conducted using the slug-test technique. In the slug-test the hydraulic head in the borehole is abruptly changed either by pouring water in the borehole or by lowering the pressure sensor. The conductivity is interpreted based on the recovery of the water level. This report presents the field measurements and their interpretation. The interpretation has been done using the Hvorslev's method, but for the control also Thiem's equation was applied. According to the results hydraulic conductivities in PP-holes range from 10{sup -9} m/s to 10{sup -4} m/s and in PVP-holes from 10{sup -6} m/s to 10{sup -4} m/s. The range is almost the same as in measurements of year 2002. Also the results from holes measured both 2002 and 2004 are very close to each other. The results agree also with hydraulic conductivity information available from the pre-pumping done in connection of the groundwater sampling. (orig.)

  9. PageRank versatility analysis of multilayer modality-based network for exploring the evolution of oil-water slug flow.

    Science.gov (United States)

    Gao, Zhong-Ke; Dang, Wei-Dong; Li, Shan; Yang, Yu-Xuan; Wang, Hong-Tao; Sheng, Jing-Ran; Wang, Xiao-Fan

    2017-07-14

    Numerous irregular flow structures exist in the complicated multiphase flow and result in lots of disparate spatial dynamical flow behaviors. The vertical oil-water slug flow continually attracts plenty of research interests on account of its significant importance. Based on the spatial transient flow information acquired through our designed double-layer distributed-sector conductance sensor, we construct multilayer modality-based network to encode the intricate spatial flow behavior. Particularly, we calculate the PageRank versatility and multilayer weighted clustering coefficient to quantitatively explore the inferred multilayer modality-based networks. Our analysis allows characterizing the complicated evolution of oil-water slug flow, from the opening formation of oil slugs, to the succedent inter-collision and coalescence among oil slugs, and then to the dispersed oil bubbles. These properties render our developed method particularly powerful for mining the essential flow features from the multilayer sensor measurements.

  10. Solar-Terrestrial Interactions

    Science.gov (United States)

    2008-01-01

    satellite for polar cap passes during large SEP events to determine the experimental geographic cutoff latitudes for the two energy ranges. 9 These...E. Lamanna, Societa Italiana di Fisica , Bologna, Italy, 1997.) Shea, M.A., and D.F. Smart, Overview of the Effects of Solar Terrestrial Phenomena...Conference, Invited, Rapporteurs, & Highlight Papers, edited by N. Iucci and E. Lamanna, Societa Italiana di Fisica , Bologna, Italy, 1997.) 27

  11. Expression of transcription factors Slug in the lens epithelial cells undergoing epithelial-mesenchymal transition induced by connective tissue growth factor

    Directory of Open Access Journals (Sweden)

    Ying-Na Wang

    2015-10-01

    Full Text Available AIM:To investigate the expression of transcription factors Slug in human lens epithelial cells (HLECs undergoing epithelial-mesenchymal transition (EMT induced by connective tissue growth factor (CTGF.METHODS: HLECs were treated with CTGF of different concentrations (20, 50 and 100 ng/mL or without CTGF (control for 24h. The morphological changes of HLECs were analysed by microscopy. The expression and cellular localization of Slug was evaluated by immumo-fluorescence. Expressions of Slug, E-cadherin and alpha smooth muscle actin (α-SMA were further determined by Western blot analysis. RESULTS: HLECs showed spidle fibrolasts-like characteristics and loosely connected each other after CTGF treatment. The immuno-fluorescence staining indicated that Slug was localized in the nuclei and its expression was induced by CTGF. The relative expressions of Slug protein were 1.64±0.11, 1.96 ±0.03, 3.12 ±0.10, and 4.08±0.14, respectively, in response to control group and treatment with CTGF of 20, 50 and 100 ng/mL (F=443.86, PCONCLUSION: Transcription factor Slug may be involved in EMT of HLECs induced by CTGF in vitro.

  12. Exchange flows of two immiscible Newtonian liquids in a vertical tube: From falling drops to falling slugs

    Science.gov (United States)

    Varges, P. R.; Fonseca, B. S.; Naccache, M. F.; de Souza Mendes, P. R.

    2017-06-01

    We present an experimental study of buoyancy-driven flows of two immiscible Newtonian liquids in a vertical tube where initially the heavier and more viscous one is placed on the top of the lighter one. Flow visualization was performed using a digital camera, and inversion velocities were determined through image analysis. The influence of the governing parameters on the speed and flow regime was examined for pairs of liquids with small density differences. Two different flow regimes were observed, namely, falling drops and falling slugs. In the first regime, spherical and ellipsoidal drops are obtained, depending on the ratio between the drop and tube diameters. The falling slug regime is a core-annular flow pattern above a critical value of interfacial tension, while no flow is noticed below this critical value. The experimental results are in good agreement with model predictions from the literature. Indeed, the results showed that terminal velocity can be estimated by empirical correlations for falling spheres.

  13. Conventional versus slug CO2 loading and the control of breathing in anaesthetized cats.

    Science.gov (United States)

    van der Grinten, C P; Schoute, E; de Vries, W R; Luijendijk, S C

    1992-01-01

    1. Conventional inspiratory CO2 loading (CCL) is accomplished by having the subject breathe CO2-enriched air. An alternative method of CO2 loading is to inject a bolus of CO2 at the start of each inspiration into the inspired air: slug CO2 loading (SCL). During SCL PCO2 in the conducting airways declines quickly towards 0 kPa in the course of inspiration, whereas PCO2 remains at a constant value equal to the inspiratory PCO2 during CCL. Therefore, CCL and SCL may stimulate the respiratory controller differently. 2. We compared the ventilatory responses to SCL and CCL in fourteen anaesthetized, spontaneously breathing cats. In each experimental animal we applied, in a fixed randomized order, five CCL experiments (fractional inspiratory CO2, FI,CO2 = 0.01-0.05), six SCL experiments (slugs of 50% CO2 ranging from 0.5 to 6 ml) and three control experiments in which no CO2 was loaded. Partial pressure of CO2 in arterial blood was determined from small blood samples (0.14 ml). In three cats we repeated the experiments after bilateral transection of the cervical vagi to evaluate the contribution of vagal receptors to the responses observed. 3. The average slope of the CO2 response curves for SCL was 2 times steeper than that for CCL (P less than 0.01). The larger minute ventilation for SCL for a particular value of arterial PCO2 (Pa,CO2) could not be attributed exclusively to the increased breathing frequency or the increased tidal volume (P greater than 0.10). Further, mean inspiratory flow (VI) was larger for SCL than for CCL at the same Pa,CO2 (P less than 0.01), also because the ratio TI/TE (inspiratory duration/expiratory duration) was smaller (P less than 0.01). After vagotomy the difference between SCL and CCL response curves was much reduced. 4. It is concluded that SCL and CCL affect the respiratory controller in a different way causing differences in breathing pattern and CO2 sensitivity between the two methods. Evidently, a mechanism based on CO2 sensitivity of

  14. Slug-tests in PP- and PVP-holes at Olkiluoto in 2012

    Energy Technology Data Exchange (ETDEWEB)

    Tammisto, E. [Poeyry Finland Oy, Vantaa (Finland)

    2014-02-15

    As part of the program for the final disposal of the nuclear fuel waste, Posiva Oy investigates the hydrological conditions at the Olkiluoto Island. The hydraulic conductivity in the shallow investigation holes OL-PP36, -PP39, -PVP4A, -PVP4B, -PVP6A, -PVP6B, -PVP14, -PVP36, -PVP37A, -PVP37B, -PVP37C, -PVP38A, -PVP38B, -PVP38C, -PVP38D, -HP1, -HP2, -HP3 and -HP4 was measured in summer 2012. The length of PP-holes is between 12 m and 14 m, and the test sections (1 m) are located in the bedrock. PVP-tubes have an average length between 4 - 15 m, and the test sections (2 m) are located in the overburden. The length of HP-tubes is 3 m or 5 m and the test sections (1 m) are located in the overburden. The measurements were carried out using the slug-test technique with 2010 renewed equipment. In the slug-test, the hydraulic head in the borehole is abruptly changed either by pouring water into the hole or by lowering the pressure sensor. The hydraulic conductivity is interpreted from the recovery of the water level. This report presents the field measurements and their interpretation. The interpretation has been done using the Hvorslev's method, and for reference, conductivity has also been calculated according to the Thiem's equation. According to the results, hydraulic conductivity in the PP-holes ranges from 10{sup -8} m/s to 10{sup -6} m/s and in the PVP- and the HP-tubes from 10{sup -8} m/s to 10{sup -5} m/s. The observed range is quite similar as in the previous measurements in 2002 and 2004-2011. In general, the results are consistent with the results obtained in the earlier measurements. In OL-PP36, the results from 2012 agree very well with the earlier results except section 8.17 - 9.17 m, in which K-values from 2007, 2008 and 2009 differ from the other years. In OL-PP39, the results agree well. There is more difference in low K-values than in higher ones. In the PVP-tubes, the variations are small. In the HP-tubes, the K-values clearly differ from the

  15. The Slug and Churn Turbulence Characteristics of Oil-Gas-Water Flows in a Vertical Small Pipe

    Science.gov (United States)

    Liu, Weixin; Han, Yunfeng; Wang, Dayang; Zhao, An; Jin, Ningde

    2017-08-01

    The intention of the present study was to investigate the slug and churn turbulence characteristics of a vertical upward oil-gas-water three-phase flow. We firstly carried out a vertical upward oil-gas-water three-phase flow experiment in a 20-mm inner diameter (ID) pipe to measure the fluctuating signals of a rotating electric field conductance sensor under different flow patterns. Afterwards, typical flow patterns were identified with the aid of the texture structures in a cross recurrence plot. Recurrence quantitative analysis and multi-scale cross entropy (MSCE) algorithms were applied to investigate the turbulence characteristics of slug and churn flows with the varying flow parameters. The results suggest that with cross nonlinear analysis, the underlying dynamic characteristics in the evolution from slug to churn flow can be well understood. The present study provides a novel perspective for the analysis of the spatial-temporal evolution instability and complexity in oil-gas-water three-phase flow.

  16. Terrestrial Steering Group. 2014. Arctic Terrestrial Biodiversity Monitoring Plan

    DEFF Research Database (Denmark)

    Aastrup, Peter; Aronsson, Mora; Barry, Tom

    implementation of the Arctic Terrestrial Biodiversity Monitoring Plan for the next two years. Identify expert networks required for successful implementation of the plan. Identify key gaps and opportunities for the TSG related to plan implementation and identify near-term next steps to address gaps.......The Terrestrial Steering Group (TSG), has initiated the implementation phase of the CBMP Terrestrial Plan. The CBMP Terrestrial Steering Group, along with a set of invited experts (see Appendix A for a participants list), met in Iceland from February 25-27th to develop a three year work plan...... to guide implementation of the CBMP-Terrestrial Plan. This report describes the outcome of that workshop. The aim of the workshop was to develop a three year work plan to guide implementation of the CBMP-Terrestrial Plan. The participants were tasked with devising an approach to both (a) determine what...

  17. Buddly, slug, and annular two-phase flow in tight-lattice subchannels

    Energy Technology Data Exchange (ETDEWEB)

    Prasser, Horst-Michael; Bolesch, Charistian; Cramer, Kerstin; Papadopoulos, Petros; Saxena, Abhishek; Zboray, Robert [ETH Zurich, Dept. of Mechanical and Process Engineering (D-MAVT), Zurich (Switzerland); Ito, Daisuke [Kyoto University, Research Reactor Institute, Osaka (Japan)

    2016-08-15

    An overview is given on the work of the Laboratory of Nuclear Energy Systems at ETH, Zurich (ETHZ) and of the Laboratory of Thermal Hydraulics at Paul Scherrer Institute (PSI), Switzerland on tight-lattice bundles. Two-phase flow in subchannels of a tight triangular lattice was studied experimentally and by computational fluid dynamics simulations. Two adiabatic facilities were used: (1) a vertical channel modeling a pair of neighboring subchannels; and (2) an arrangement of four subchannels with one subchannel in the center. The first geometry was equipped with two electrical film sensors placed on opposing rod surfaces forming the subchannel gap. They recorded 2D liquid film thickness distributions on a domain of 16 × 64 measuring points each, with a time resolution of 10 kHz. In the bubbly and slug flow regime, information on the bubble size, shape, and velocity and the residual liquid film thickness underneath the bubbles were obtained. The second channel was investigated using cold neutron tomography, which allowed the measurement of average liquid film profiles showing the effect of spacer grids with vanes. The results were reproduced by large eddy simulation + volume of fluid. In the outlook, a novel nonadiabatic subchannel experiment is introduced that can be driven to steady-state dryout. A refrigerant is heated by a heavy water circuit, which allows the application of cold neutron tomography.

  18. Neuronal Responses to Water Flow in the Marine Slug Tritonia diomedea

    Directory of Open Access Journals (Sweden)

    James A. Murray

    2005-01-01

    Full Text Available The marine slug Tritonia diomedea mustrely on its ability to touch and smell in order to navigate because it is blind. The primaryfactor that influences its crawling direction is the direction of water flow (caused bytides in nature. The sensory cells that detect flow and determine flow directionhave not been identified. The lateral branch of Cerebral Nerve 2 (latCeN2 has beenidentified as the nerve that carries sensory axons to the brain from the flow receptors inthe oral tentacles. Backfilling this nerve to the brain resulted in the labeling of a numberof cells located throughout the brain. Most of the labeled cells are concentrated in the cerebral ganglion where the nerve enters thebrain. The medial and lateral branches of CeN2 were backfilled for comparison of thepattern of cells from each nerve. A map of the cells innervated by latCeN2 reveals thelocation of the stained cells. Extracellular recording from latCeN2 revealed itsinvolvement in the detection of water flow and orientation. The nerve becomes activein response to water flow stimulation. Intracellular recordings of the electricalactivity of these cells in a live animal will be the next step to determine if these cells arethe flow receptors.

  19. Neuronal responses to water flow in the marine slug tritonia diomedea

    Directory of Open Access Journals (Sweden)

    Jeffrey Blackwell

    2005-07-01

    Full Text Available The marine slug Tritonia diomedea must rely on its ability to touch and smell in order to navigate because it is blind. The primary factor that influences its crawling direction is the direction of water flow (caused by tides in nature. The sensory cells that detect flow and determine flow direction have not been identified. The lateral branch of Cerebral Nerve 2 (latCeN2 has been identified as the nerve that carries sensory axons to the brain from the flow receptors inthe oral tentacles. Backfilling this nerve to the brain resulted in the labeling of a number of cells located throughout the brain. Most of the labeled cells are concentrated in the cerebral ganglion where the nerve enters the brain. The medial and lateral branches of CeN2 were backfilled for comparison of the pattern of cells from each nerve. A map of the cells innervated by latCeN2 reveals the location of the stained cells. Extracellular recording from latCeN2 revealed its involvement in the detection of water flow and orientation. The nerve becomes active in response to water flow stimulation. Intracellular recordings of the electrical activity of these cells in a live animal will be the next step to determine if these cells are the flow receptors.

  20. Turning snails into slugs: induced body plan changes and formation of an internal shell.

    Science.gov (United States)

    Osterauer, Raphaela; Marschner, Leonie; Betz, Oliver; Gerberding, Matthias; Sawasdee, Banthita; Cloetens, Peter; Haus, Nadine; Sures, Bernd; Triebskorn, Rita; Köhler, Heinz-R

    2010-01-01

    The archetypal body plan of conchiferan molluscs is characterized by an external calcareous shell, though internalization of shells has evolved independently in a number of molluscan clades, including gastropod families. In gastropods, the developmental process of torsion is regarded as a hallmark that is associated with a new anatomical configuration. This configuration is present in extant prosobranch gastropod species, which predominantly bear external shells. Here, we show that short-term exposure to platinum during development uncouples at least two of the processes associated with torsion of the freshwater snail Marisa cornuarietis. That is, the anus of the treated snails is located anteriorly, but the gill and the designated mantle tissue remains in a posterior location, thus preventing the formation of an external shell. In contrast to the prosobranchian archetype, platinum treatment results in the formation of a posterior gill and a cone-shaped internal shell, which persists across the lifetime. This first finding of artificially induced snail-slug conversion was also seen in the pulmonate snail Planorbarius corneus and demonstrates that selective alteration of embryonic key processes can result in fundamental changes of an existing body plan and-if altered regulation is inherited-may give rise to a new one. © 2010 Wiley Periodicals, Inc.

  1. Bubbly, Slug, and Annular Two-Phase Flow in Tight-Lattice Subchannels

    Directory of Open Access Journals (Sweden)

    Horst-Michael Prasser

    2016-08-01

    Full Text Available An overview is given on the work of the Laboratory of Nuclear Energy Systems at ETH, Zurich (ETHZ and of the Laboratory of Thermal Hydraulics at Paul Scherrer Institute (PSI, Switzerland on tight-lattice bundles. Two-phase flow in subchannels of a tight triangular lattice was studied experimentally and by computational fluid dynamics simulations. Two adiabatic facilities were used: (1 a vertical channel modeling a pair of neighboring subchannels; and (2 an arrangement of four subchannels with one subchannel in the center. The first geometry was equipped with two electrical film sensors placed on opposing rod surfaces forming the subchannel gap. They recorded 2D liquid film thickness distributions on a domain of 16 × 64 measuring points each, with a time resolution of 10 kHz. In the bubbly and slug flow regime, information on the bubble size, shape, and velocity and the residual liquid film thickness underneath the bubbles were obtained. The second channel was investigated using cold neutron tomography, which allowed the measurement of average liquid film profiles showing the effect of spacer grids with vanes. The results were reproduced by large eddy simulation + volume of fluid. In the outlook, a novel nonadiabatic subchannel experiment is introduced that can be driven to steady-state dryout. A refrigerant is heated by a heavy water circuit, which allows the application of cold neutron tomography.

  2. Two-fluid model for transient analysis of slug flow in oil wells

    Energy Technology Data Exchange (ETDEWEB)

    Cazarez-Candia, O., E-mail: ocazarez@imp.mx [Instituto Mexicano del Petroleo, Eje central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, Mexico D.F. 07730 (Mexico); Instituto Tecnologico de Zacatepec, Depto. de Metal-Mecanica, Calzada Tecnologico, No. 27, Zacatepec, Morelos 62780 (Mexico); Benitez-Centeno, O.C. [Centro Nacional de Investigacion y Desarrollo Tecnologico, Depto. de Mecanica, Interior Internado Palmira s/n, Col. Palmira, Cuernavaca, Morelos 62490 (Mexico); Espinosa-Paredes, G. [Area de Ingenieria en Recursos Energeticos, Universidad Autonoma Metropolitana-Iztapalapa, Av San Rafael Atlixco No 186, Col. Vicentina 55-534, Mexico D.F. 09340 (Mexico)

    2011-06-15

    In this work it is presented a transient, one-dimensional, adiabatic model for slug flow simulation, which appears when liquid (mixture of oil and water) and gas flow simultaneously through pipes. The model is formed by space and time averaged conservation equations for mass, momentum and energy for each phase, the numerical solution is based on the finite difference technique in the implicit scheme. Velocity, pressure, volumetric fraction and temperature profiles for both phases were predicted for inclination angles from the horizontal to the vertical position (unified model) and ascendant flow. Predictions from the model were validated using field data and ten correlations commonly used in the oil industry. The effects of gas heating or cooling, due to compression and expansion processes, on the predictions and numerical stability, were studied. It was found that when these effects are taken into account, a good behavior of temperature predictions and numerical stability are obtained. The model presents deviations lower than 14% regarding field data and it presents better predictions than most of the correlations.

  3. Modification of a compressor performance test bench for liquid slugging observation in refrigeration compressors

    Science.gov (United States)

    Ola, Max; Thomas, Christiane; Hesse, Ullrich

    2017-08-01

    Compressor performance test procedures are defined by the standard DIN EN 13771, wherein a variety of possible calorimeter and flow rate measurement methods are suggested. One option is the selection of two independent measurement methods. The accuracies of both selected measurement methods are essential. The second option requires only one method. However the measurement accuracy of the used device has to be verified and recalibrated on a regular basis. The compressor performance test facility at the Technische Universitaet Dresden uses a calibrated flow measurement sensor, a hot gas bypass and a mixed flow heat exchanger. The test bench can easily be modified for tests of various compressor types at different operating ranges and with various refrigerants. In addition, the modified test setup enables the investigation of long term liquid slug and its effects on the compressor. The modification comprises observational components, adjustments of the control system, safety measures and a customized oil recirculation system for compressors which do not contain an integrated oil sump or oil level regulation system. This paper describes the setup of the test bench, its functional principle, the key modifications, first test results and an evaluation of the energy balance.

  4. On the solutions of modeling a slug test performed in a two-zone confined aquifer

    Science.gov (United States)

    Shaw-Yang, Yang; Hund-der, Yeh

    2007-03-01

    The slug test is a popular field method for estimating aquifer parameters. As a finite-thickness skin is present at a wellbore, the result of test-data analysis may represent average hydraulic properties of the skin and formation zones. Moench and Hsieh (Int. Assoc. of Hydrogeology, The IAH 17th International Congress on Hydrology of Rocks of Low Permeability, Int. Assoc. of Hydrogeology. Tucson, Arizona, 7 12 January) provided the Laplace-domain solution for a confined aquifer with a finite-thickness skin that satisfies the governing equations, boundary conditions, and continuity requirements at the interface of the skin and formation zones. Two new formulae presented here relate the modified zero-order Bessel functions of the first and second kinds to their first and second derivatives. Their solution is evaluated using the modified Crump approach for the Laplace inversion. The numerical values obtained by the modified Crump approach are compared with others based on finite-element modeling. The results indicate that the values based on finite-element modeling exhibit poor accuracy, attributed to errors in the mass balance equation and interface condition in their mathematical model.

  5. Microstructure of terrestrial catastrophism

    Energy Technology Data Exchange (ETDEWEB)

    Clube, S.V.M. (Oxford Univ. (UK). Dept. of Astrophysics); Napier, W.M. (Royal Observatory, Edinburgh (UK))

    1984-12-15

    The theory of evolution involving episodic terrestrial catastrophism predicts that the Oort cloud is disturbed by close encounters with massive nebulae. Each disturbance generates bombardment pulses of a few million years duration, the pulse frequencies being determined by the Sun's passage through the spiral arms and central plane of the Galaxy where nebulae concentrate. The structure within a pulse is shown here to be dominated by a series of 'spikes' of approx. 0.01-0.1 Myr duration separated by approx. 0.1-1.0 Myr, each caused by the arrival in circumterrestrial space of the largest comets followed by their disintegration into short-lived Apollo asteroids. Evidence is presented that a bombardment pulse was induced 3-5 Myr ago and that a 'spike' in the form of debris from a Chiron-like progenitor of Encke's comet has dominated the terrestrial environment for the last 0.02 Myr.

  6. Terrestrial Plume Impingement Testbed Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Masten Space Systems proposes to create a terrestrial plume impingement testbed for generating novel datasets for extraterrestrial robotic missions. This testbed...

  7. Conservation at a slow pace: terrestrial gastropods facing fast-changing climate.

    Science.gov (United States)

    Nicolai, Annegret; Ansart, Armelle

    2017-01-01

    The climate is changing rapidly, and terrestrial ectotherms are expected to be particularly vulnerable to changes in temperature and water regime, but also to an increase in extreme weather events in temperate regions. Physiological responses of terrestrial gastropods to climate change are poorly studied. This is surprising, because they are of biodiversity significance among litter-dwelling species, playing important roles in ecosystem function, with numerous species being listed as endangered and requiring efficient conservation management. Through a summary of our ecophysiological work on snail and slug species, we gained some insights into physiological and behavioural responses to climate change that we can organize into the following four threat categories. (i) Winter temperature and snow cover. Terrestrial gastropods use different strategies to survive sub-zero temperatures in buffered refuges, such as the litter or the soil. Absence of the insulating snow cover exposes species to high variability in temperature. The extent of specific cold tolerance might influence the potential of local extinction, but also of invasion. (ii) Drought and high temperature. Physiological responses involve high-cost processes that protect against heat and dehydration. Some species decrease activity periods, thereby reducing foraging and reproduction time. Related costs and physiological limits are expected to increase mortality. (iii) Extreme events. Although some terrestrial gastropod communities can have a good resilience to fire, storms and flooding, an increase in the frequency of those events might lead to community impoverishment. (iv) Habitat loss and fragmentation. Given that terrestrial gastropods are poorly mobile, landscape alteration generally results in an increased risk of local extinction, but responses are highly variable between species, requiring studies at the population level. There is a great need for studies involving non-invasive methods on the

  8. Terrestrial Carbon Cycle Variability.

    Science.gov (United States)

    Baldocchi, Dennis; Ryu, Youngryel; Keenan, Trevor

    2016-01-01

    A growing literature is reporting on how the terrestrial carbon cycle is experiencing year-to-year variability because of climate anomalies and trends caused by global change. As CO 2 concentration records in the atmosphere exceed 50 years and as satellite records reach over 30 years in length, we are becoming better able to address carbon cycle variability and trends. Here we review how variable the carbon cycle is, how large the trends in its gross and net fluxes are, and how well the signal can be separated from noise. We explore mechanisms that explain year-to-year variability and trends by deconstructing the global carbon budget. The CO 2 concentration record is detecting a significant increase in the seasonal amplitude between 1958 and now. Inferential methods provide a variety of explanations for this result, but a conclusive attribution remains elusive. Scientists have reported that this trend is a consequence of the greening of the biosphere, stronger northern latitude photosynthesis, more photosynthesis by semi-arid ecosystems, agriculture and the green revolution, tropical temperature anomalies, or increased winter respiration. At the global scale, variability in the terrestrial carbon cycle can be due to changes in constituent fluxes, gross primary productivity, plant respiration and heterotrophic (microbial) respiration, and losses due to fire, land use change, soil erosion, or harvesting. It remains controversial whether or not there is a significant trend in global primary productivity (due to rising CO 2 , temperature, nitrogen deposition, changing land use, and preponderance of wet and dry regions). The degree to which year-to-year variability in temperature and precipitation anomalies affect global primary productivity also remains uncertain. For perspective, interannual variability in global gross primary productivity is relatively small (on the order of 2 Pg-C y -1 ) with respect to a large and uncertain background (123 +/- 4 Pg-C y -1 ), and

  9. Terrestrial plant methane production

    DEFF Research Database (Denmark)

    Mikkelsen, Teis Nørgaard; Bruhn, Dan; Møller, Ian M.

    We evaluate all experimental work published on the phenomenon of aerobic methane (CH4) generation in terrestrial plants. We conclude that the phenomenon is true. Four stimulating factors have been observed to induce aerobic plant CH4 production, i.e. cutting injuries, increasing temperature......, ultraviolet radiation and reactive oxygen species. Further, we analyze rates of measured emission of aerobically produced CH4 in pectin and in plant tissues from different studies and argue that pectin is very far from the sole contributing precursor. Hence, scaling up of aerobic CH4 emission needs to take...... the aerobic methane emission in plants. Future work is needed for establishing the relative contribution of several proven potential CH4 precursors in plant material....

  10. Space Weather: Terrestrial Perspective

    Directory of Open Access Journals (Sweden)

    Pulkkinen Tuija

    2007-05-01

    Full Text Available Space weather effects arise from the dynamic conditions in the Earth’s space environment driven by processes on the Sun. While some effects are influenced neither by the properties of nor the processes within the Earth’s magnetosphere, others are critically dependent on the interaction of the impinging solar wind with the terrestrial magnetic field and plasma environment. As the utilization of space has become part of our everyday lives, and as our lives have become increasingly dependent on technological systems vulnerable to space weather influences, understanding and predicting hazards posed by the active solar events has grown in importance. This review introduces key dynamic processes within the magnetosphere and discusses their relationship to space weather hazards.

  11. Emodin Inhibits the Epithelial to Mesenchymal Transition of Epithelial Ovarian Cancer Cells via ILK/GSK-3β/Slug Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Jingjing Lu

    2016-01-01

    Full Text Available Epithelial ovarian cancer (EOC is the most lethal gynecologic malignancy. Despite the anticancer capabilities of emodin observed in many cancers, including EOC, the underlying molecular mechanism remains to be elucidated. A crucial link has been discovered between the acquisition of metastatic traits and the epithelial-mesenchymal transition (EMT. The present study aimed to determine whether emodin could inhibit the EMT of EOC cells and explore the underlying mechanism. The CCK-8 assay and transwell assay showed that emodin effectively repressed the abilities of proliferation, invasion, and migration in A2780 and SK-OV-3 cells. The Western blot showed that emodin upregulated epithelial markers (E-cadherin and Claudin while it downregulated mesenchymal markers (N-cadherin and Vimentin and transcription factor (Slug in a dose-dependent fashion. After transfection of siRNA-Slug, both Slug and N-cadherin were downregulated in EOC cells while E-cadherin was upregulated, which was intensified by emodin. Besides, emodin decreased the expression of ILK, p-GSK-3β, β-catenin, and Slug. Transfection of siRNA-ILK also achieved the same effects, which was further strengthened by following emodin treatment. Nevertheless, SB216763, an inhibitor of GSK-3β, could reverse the effects of emodin except for ILK expression. These findings suggest that emodin inhibited the EMT of EOC cells via ILK/GSK-3β/Slug signaling pathway.

  12. Exploring the IMF of star clusters: a joint SLUG and LEGUS effort

    Science.gov (United States)

    Ashworth, G.; Fumagalli, M.; Krumholz, M. R.; Adamo, A.; Calzetti, D.; Chandar, R.; Cignoni, M.; Dale, D.; Elmegreen, B. G.; Gallagher, J. S., III; Gouliermis, D. A.; Grasha, K.; Grebel, E. K.; Johnson, K. E.; Lee, J.; Tosi, M.; Wofford, A.

    2017-08-01

    We present the implementation of a Bayesian formalism within the Stochastically Lighting Up Galaxies (slug) stellar population synthesis code, which is designed to investigate variations in the initial mass function (IMF) of star clusters. By comparing observed cluster photometry to large libraries of clusters simulated with a continuously varying IMF, our formalism yields the posterior probability distribution function (PDF) of the cluster mass, age and extinction, jointly with the parameters describing the IMF. We apply this formalism to a sample of star clusters from the nearby galaxy NGC 628, for which broad-band photometry in five filters is available as part of the Legacy ExtraGalactic UV Survey (LEGUS). After allowing the upper-end slope of the IMF (α3) to vary, we recover PDFs for the mass, age and extinction that are broadly consistent with what is found when assuming an invariant Kroupa IMF. However, the posterior PDF for α3 is very broad due to a strong degeneracy with the cluster mass, and it is found to be sensitive to the choice of priors, particularly on the cluster mass. We find only a modest improvement in the constraining power of α3 when adding Hα photometry from the companion Hα-LEGUS survey. Conversely, Hα photometry significantly improves the age determination, reducing the frequency of multi-modal PDFs. With the aid of mock clusters, we quantify the degeneracy between physical parameters, showing how constraints on the cluster mass that are independent of photometry can be used to pin down the IMF properties of star clusters.

  13. 3-dimensional Simulation of an Air-lift Pump from Bubbly to Slug Flow

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Hongrae; Jo, Daeseong [Kyungpook National Univ, Daegu (Korea, Republic of)

    2015-10-15

    The air-lift pump has been used in various applications with its merit that it can pump up without any moving parts. E.g. coffee percolator, petroleum industry, suction dredge, OTEC i.e. ocean thermal energy conversion and so on. By the merit, it has high durability for high temperature water or vapor, and fluid-solid mixture like waste water, muddy water and crude, which cause problems when it's pumped up with general pumps. In this regard, the air-lift pump has been one of the most desirable technology. A typical air-lift pump configuration is illustrated in Figure 01. The principle of this pump is very simple. When air is injected from the injector at bottom of a submerged tube, i.e., air bubbles are suspended in the liquid, the average density of the mixture in the tube is less than that of the surrounding fluid in the reservoir. Then hydrostatic pressure over the length of the tube is decreased. This buoyancy force causes a pumping action. The comparison of the simulated results, experimental result, and theoretical result is been able by data shown as Figure 04. They have similar trends but they also have a little differences because there are some limits of simulating the flow regimes. At the different flow condition, different coefficients for friction factor or pressure drop should be used, but this simulation uses a laminar condition and the theoretical equations are valid only for slug regime where the air flow rate is lower than the other regimes. From these causes, the differences has arisen, and difference comes bigger as the air flow rate increases, i.e., becoming annular flow regime or churn flow regime.

  14. Multi-level slug tests in highly permeable formations: 2. Hydraulic conductivity identification, method verification, and field applications

    Science.gov (United States)

    Zlotnik, V.A.; McGuire, V.L.

    1998-01-01

    Using the developed theory and modified Springer-Gelhar (SG) model, an identification method is proposed for estimating hydraulic conductivity from multi-level slug tests. The computerized algorithm calculates hydraulic conductivity from both monotonic and oscillatory well responses obtained using a double-packer system. Field verification of the method was performed at a specially designed fully penetrating well of 0.1-m diameter with a 10-m screen in a sand and gravel alluvial aquifer (MSEA site, Shelton, Nebraska). During well installation, disturbed core samples were collected every 0.6 m using a split-spoon sampler. Vertical profiles of hydraulic conductivity were produced on the basis of grain-size analysis of the disturbed core samples. These results closely correlate with the vertical profile of horizontal hydraulic conductivity obtained by interpreting multi-level slug test responses using the modified SG model. The identification method was applied to interpret the response from 474 slug tests in 156 locations at the MSEA site. More than 60% of responses were oscillatory. The method produced a good match to experimental data for both oscillatory and monotonic responses using an automated curve matching procedure. The proposed method allowed us to drastically increase the efficiency of each well used for aquifer characterization and to process massive arrays of field data. Recommendations generalizing this experience to massive application of the proposed method are developed.Using the developed theory and modified Springer-Gelhar (SG) model, an identification method is proposed for estimating hydraulic conductivity from multi-level slug tests. The computerized algorithm calculates hydraulic conductivity from both monotonic and oscillatory well responses obtained using a double-packer system. Field verification of the method was performed at a specially designed fully penetrating well of 0.1-m diameter with a 10-m screen in a sand and gravel alluvial

  15. Multi-level slug tests in highly permeable formations: 1. Modification of the Springer-Gelhar (SG) model

    Science.gov (United States)

    Zlotnik, V.A.; McGuire, V.L.

    1998-01-01

    A multi-level slug test model and a method for the evaluation of vertical profiles of hydraulic conductivity in highly permeable formations are developed. A double-packer system is employed to estimate local hydraulic conductivity. Depending on the formation and double-packer system parameters, the water level recovery in the tested well can exhibit a monotonic or oscillatory response. To discern information on aquifer properties from artifacts introduced by the measurement system, the theory of flow in an aquifer and a double-packer system is developed. The mathematical model incorporates features of the Springer and Gelhar (1991) model and reduces to the Bouwer and Rice (1976) model in a special case. The model involves equations of momentum and mass conservation for the double-packer system with quasi-steady well-aquifer interaction equations. The method is uniformly applicable for both monotonic and oscillatory well responses and can produce profiles of hydraulic conductivity for the tested well. The criterion is given to determine the type of well response for given slug test conditions.A multi-level slug test model and a method for the evaluation of vertical profiles of hydraulic conductivity in highly permeable formations are developed. A double-packer system is employed to estimate local hydraulic conductivity. Depending on the formation and double-packer system parameters, the water level recovery in the tested well can exhibit a monotonic or oscillatory response. To discern information on aquifer properties from artifacts introduced by the measurement system, the theory of flow in an aquifer and a double-packer system is developed. The mathematical model incorporates features of the Springer and Gelhar (1991) model and reduces to the Bouwer and Rice (1976) model in a special case. The model involves equations of momentum and mass conservation for the double-packer system with quasi-steady well-aquifer interaction equations. The method is uniformly

  16. Terrestrial locomotion in arachnids.

    Science.gov (United States)

    Spagna, Joseph C; Peattie, Anne M

    2012-05-01

    In this review, we assess the current state of knowledge on terrestrial locomotion in Arachnida. Arachnids represent a single diverse (>100,000 species) clade containing well-defined subgroups (at both the order and subordinal levels) that vary morphologically around a basic body plan, yet exhibit highly disparate limb usage, running performance, and tarsal attachment mechanisms. Spiders (Araneae), scorpions (Scorpiones), and harvestmen (Opiliones) have received the most attention in the literature, while some orders have never been subject to rigorous mechanical characterization. Most well-characterized taxa move with gaits analogous to the alternating tripod gaits that characterize fast-moving Insecta - alternating tetrapods or alternating tripods (when one pair of legs is lifted from the ground for some other function). However, between taxa, there is considerable variation in the regularity of phasing between legs. Both large and small spiders appear to show a large amount of variation in the distribution of foot-ground contact, even between consecutive step-cycles of a single run. Mechanisms for attachment to vertical surfaces also vary, and may depend on tufts of adhesive hairs, fluid adhesives, silks, or a combination of these. We conclude that Arachnida, particularly with improvements in microelectronic force sensing technology, can serve as a powerful study system for understanding the kinematics, dynamics, and ecological correlates of sprawled-posture locomotion. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Chloroplast digestion and the development of functional kleptoplasty in juvenile Elysia timida (Risso, 1818 as compared to short-term and non-chloroplast-retaining sacoglossan slugs.

    Directory of Open Access Journals (Sweden)

    Elise Marie Jerschabek Laetz

    Full Text Available Sacoglossan sea slugs are the only metazoans known to perform functional kleptoplasty, the sequestration and retention of functional chloroplasts within their digestive gland cells. Remarkably, a few species with this ability can survive starvation periods of 3-12 months likely due to their stolen chloroplasts. There are no reports of kleptoplast transfer from mother slug to either eggs or juveniles, demonstrating that each animal must independently acquire its kleptoplasts and develop the ability to maintain them within its digestive gland. We present here an investigation into the development of functional kleptoplasty in a long-term kleptoplast retaining species, Elysia timida. Laboratory-reared juvenile slugs of different post-metamorphic ages were placed in starvation and compared to 5 known short-term retaining slug species and 5 non-retaining slug species. The subsequent results indicate that functional kleptoplasty is not performed by E. timida until after 15 days post-metamorphosis and that by 25 days, these animals outlive many of the short-term retention species. Digestive activity was also monitored using lysosomal abundance as an indicator, revealing different patterns in starving juveniles versus adults. Starved juveniles were reintroduced to food to determine any differences in digestive activity when starvation ends, resulting in an increase in the number of kleptoplasts, but no overall change in lysosomal activity. By revealing some of the changes that occur during early development in these animals, which begin as non-kleptoplast-retaining and grow into long-term retaining slugs, this investigation provides a basis for future inquiries into the origin and development of this remarkable ability.

  18. Aquatic and Terrestrial Environment 2004

    DEFF Research Database (Denmark)

    Andersen, J. M.; Boutrup, S.; Bijl, L. van der

    This report presents the 2004 results of the Danish National Monitoring and Assess-ment Programme for the Aquatic and Terrestrial Environments (NOVANA). 2004 was the first year in which terrestrial nature was included in the monitoring pro-gramme. The report reviews the state of the groundwater......, watercourses, lakes and marine waters and the pressures upon them and reviews the monitoring of terrestrial natural habitats and selected plants and animals. The report is based on the annual reports prepared for each subprogramme by the Topic Centres. The latter reports are mainly based on data collected...

  19. VEGFA links self-renewal and metastasis by inducing Sox2 to repress miR-452, driving Slug.

    Science.gov (United States)

    Kim, M; Jang, K; Miller, P; Picon-Ruiz, M; Yeasky, T M; El-Ashry, D; Slingerland, J M

    2017-09-07

    Cancer stem cells (CSC) appear to have increased metastatic potential, but mechanisms underlying this are poorly defined. Here we show that VEGFA induction of Sox2 promotes EMT and tumor metastasis. In breast lines and primary cancer culture, VEGFA rapidly upregulates SOX2 expression, leading to SNAI2 induction, EMT, increased invasion and metastasis. We show Sox2 downregulates miR-452, which acts as a novel metastasis suppressor to directly target the SNAI2 3'-untranslated region (3'-UTR). VEGFA stimulates Sox2- and Slug-dependent cell invasion. VEGFA increases lung metastasis in vivo, and this is abrogated by miR-452 overexpression. Furthermore, SNAI2 transduction rescues metastasis suppression by miR-452. Thus, in addition to its angiogenic action, VEGFA upregulates Sox2 to drive stem cell expansion, together with miR-452 loss and Slug upregulation, providing a novel mechanism whereby cancer stem cells acquire metastatic potential. Prior work showed EMT transcription factor overexpression upregulates CSC. Present work indicates that stemness and metastasis are a two-way street: Sox2, a major mediator of CSC self-renewal, also governs the metastatic process.

  20. Human cancer cells express Slug-based epithelial-mesenchymal transition gene expression signature obtained in vivo

    Directory of Open Access Journals (Sweden)

    Anastassiou Dimitris

    2011-12-01

    Full Text Available Abstract Background The biological mechanisms underlying cancer cell motility and invasiveness remain unclear, although it has been hypothesized that they involve some type of epithelial-mesenchymal transition (EMT. Methods We used xenograft models of human cancer cells in immunocompromised mice, profiling the harvested tumors separately with species-specific probes and computationally analyzing the results. Results Here we show that human cancer cells express in vivo a precise multi-cancer invasion-associated gene expression signature that prominently includes many EMT markers, among them the transcription factor Slug, fibronectin, and α-SMA. We found that human, but not mouse, cells express the signature and Slug is the only upregulated EMT-inducing transcription factor. The signature is also present in samples from many publicly available cancer gene expression datasets, suggesting that it is produced by the cancer cells themselves in multiple cancer types, including nonepithelial cancers such as neuroblastoma. Furthermore, we found that the presence of the signature in human xenografted cells was associated with a downregulation of adipocyte markers in the mouse tissue adjacent to the invasive tumor, suggesting that the signature is triggered by contextual microenvironmental interactions when the cancer cells encounter adipocytes, as previously reported. Conclusions The known, precise and consistent gene composition of this cancer mesenchymal transition signature, particularly when combined with simultaneous analysis of the adjacent microenvironment, provides unique opportunities for shedding light on the underlying mechanisms of cancer invasiveness as well as identifying potential diagnostic markers and targets for metastasis-inhibiting therapeutics.

  1. Susceptibility of the eggs of the field slug Deroceras reticulatum to contact with pesticides and substances of biological origin on artificial soil

    NARCIS (Netherlands)

    Iglesias, J.; Castillejo, J.; Ester, A.; Castro, R.; Lombardia, M.J.

    2002-01-01

    The toxicity of 14 substances, including a number of pesticides, to the eggs of the pest slug Deroceras reticulatum was determined in laboratory experiments. Eggs were kept in contact with a precisely defined artificial soil to which a range of concentrations of the test substances had been applied.

  2. Toxicological evaluation of a bioadhesive nasal powder containing a starch and Carbopol 974 P on rabbit nasal mucosa and slug mucosa.

    Science.gov (United States)

    Callens, C; Adriaens, E; Dierckens, K; Remon, J P

    2001-09-11

    The purpose of this study is the investigation of possible adverse effects of a powder formulation containing drum-dried waxy maize (DDWM) starch and Carbopol 974 P (90/10) on the nasal mucosa of rabbits and the foot mucosa of slugs after multiple administrations. In the rabbit, the effect of the formulation was measured by the release of proteins and lactate dehydrogenase (LDH) from the nasal mucosa with a new non-invasive in vivo method and also by histopathology. The mucosal toxicity of the formulation was evaluated using slugs by measuring the effect on the body weight and the amount of mucus produced during a repeated contact period. Additionally, the release of proteins, lactate dehydrogenase and alkaline phosphatase from the body wall of the slugs after a repeated treatment was measured. Twenty four hours after the powder administration to the rabbits the release of the marker molecules was comparable with the negative controls. The histopathological study showed only a slight increase of granulocytes in the epithelium. The formulation induced a higher mucus production in the slugs but no additional effects were detected on the body weight and on the release of proteins. No enzymes were released from the body wall. The results indicate that the effect of the bioadhesive powder consisting of DDWM/Carbopol 974 P (90:10, w/w) on the mucosa was negligible.

  3. Study of hydrocarbon miscible solvent slug injection process for improved recovery of heavy oil from Schrader Bluff Pool, Milne Point Unit, Alaska. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    The National Energy Strategy Plan (NES) has called for 900,000 barrels/day production of heavy oil in the mid-1990s to meet our national needs. To achieve this goal, it is important that the Alaskan heavy oil fields be brought to production. Alaska has more than 25 billion barrels of heavy oil deposits. Conoco, and now BP Exploration have been producing from Schrader Bluff Pool, which is part of the super heavy oil field known as West Sak Field. Schrader Bluff reservoir, located in the Milne Point Unit, North Slope of Alaska, is estimated to contain up to 1.5 billion barrels of (14 to 21{degrees}API) oil in place. The field is currently under production by primary depletion; however, the primary recovery will be much smaller than expected. Hence, waterflooding will be implemented earlier than anticipated. The eventual use of enhanced oil recovery (EOR) techniques, such as hydrocarbon miscible solvent slug injection process, is vital for recovery of additional oil from this reservoir. The purpose of this research project was to determine the nature of miscible solvent slug which would be commercially feasible, to evaluate the performance of the hydrocarbon miscible solvent slug process, and to assess the feasibility of this process for improved recovery of heavy oil from Schrader Bluff reservoir. The laboratory experimental work includes: slim tube displacement experiments and coreflood experiments. The components of solvent slug includes only those which are available on the North Slope of Alaska.

  4. Numerical Study on Bubble Dynamics and Two-Phase Frictional Pressure Drop of Slug Flow Regime in Adiabatic T-junction Square Microchannel

    Directory of Open Access Journals (Sweden)

    K. Kishor

    2017-10-01

    Full Text Available In this study, bubble dynamics and frictional pressure drop associated with gas liquid two-phase slug flow regime in adiabatic T-junction square microchannel has been investigated using CFD. A comprehensive study on the mechanism of bubble formation via squeezing and shearing regime is performed. The randomness and recirculation profiles observed in the squeezing regime are significantly higher as compared to the shearing regime during formation of the slug. Further, effects of increasing gas velocity on bubble length are obtained at fixed liquid velocities and simulated data displayed good agreement with available correlations in literature. The frictional pressure drop for slug flow regime from simulations are also obtained and evaluated against existing separated flow models. A regression correlation has also been developed by modifying C-parameter using separated flow model, which improves the prediction of two-phase frictional pressure drop data within slug flow region, with mean absolute error of 10 %. The influences of fluid properties such as liquid viscosity and surface tension on the two-phase frictional pressure drop are also investigated and compared with developed correlation. The higher liquid viscosity and lower surface tension value resulted in bubble formation via shearing regime.

  5. Effect of Gas- and Liquid-injection Methods on Formation of Bubble and Liquid Slug at Merging Micro T-junction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jun Kyoung [Kyungnam Univ., Changwon (Korea, Republic of); Lee, Chi Young [Pukyong Nat’l Univ., Busan (Korea, Republic of)

    2016-04-15

    In the present experimental study, the effect of gas- and liquid-injected methods on the formation of bubble and liquid slug at the merging micro T-junction of a square microchannel with dimensions 600 μm × 600 μm was investigated. Nitrogen and water were used as test fluids. The superficial velocities of the liquid and gas were in the range of 0.05 - 1 m/s, and 0.1 - 1 m/s, respectively, where the Taylor flow was observed. The bubble length, liquid slug length, bubble velocity, and bubble generation frequency were measured by analyzing the images captured using a high-speed camera. Under similar inlet superficial velocity conditions, in the case of gas injection to the main channel at the merging T-junction (T{sub g}as-liquid), the lengths of the bubble and liquid slug were longer, and the bubble generation frequency was lower than in the case of liquid injection to the main channel at the merging T-junction (T{sub l}iquid-gas). On the other hand, in both cases, the bubble velocity was almost the same. The previous correlation proposed using experimental data for T{sub l}iquid-gas had predicted the present experimental data of bubble length, bubble velocity, liquid slug length, and bubble generation frequency for T{sub g}as-liquid to be ~24%, ~9%, ~39%, ~55%, respectively.

  6. Cooperation of Sox4 with β-catenin/p300 complex in transcriptional regulation of the Slug gene during divergent sarcomatous differentiation in uterine carcinosarcoma.

    Science.gov (United States)

    Inoue, Hisako; Takahashi, Hiroyuki; Hashimura, Miki; Eshima, Koji; Akiya, Masashi; Matsumoto, Toshihide; Saegusa, Makoto

    2016-02-03

    Uterine carcinosarcoma (UCS) represents a true example of cancer associated with epithelial-mesenchymal transition (EMT), which exhibits cancer stem cell (CSC)-like traits. Both Sox and β-catenin signal transductions play key roles in the regulation of EMT/CSC properties, but little is known about their involvement in UCS tumorigenesis. Herein, we focused on the functional roles of the Sox/β-catenin pathway in UCSs. EMT/CSC tests and transfection experiments were carried out using three endometrial carcinoma (Em Ca) cell lines. Immunohistochemical investigation was also applied for a total of 32 UCSs. Em Ca cells cultured in STK2, a serum-free medium for mesenchymal stem cells, underwent changes in morphology toward an EMT appearance through downregulation of E-cadherin, along with upregulation of Slug, known as a target gene of β-catenin. The cells also showed CSC properties with an increase in the aldehyde dehydrogenase (ALDH) 1(high) activity population and spheroid formation, as well as upregulation of Sox4, Sox7, and Sox9. Of these Sox factors, overexpression of Sox4 dramatically led to transactivation of the Slug promoter, and the effects were further enhanced by cotransfection of Sox7 or Sox9. Sox4 was also able to promote β-catenin-mediated transcription of the Slug gene through formation of transcriptional complexes with β-catenin and p300, independent of TCF4 status. In clinical samples, both nuclear β-catenin and Slug scores were significantly higher in the sarcomatous elements as compared to carcinomatous components in UCSs, and were positively correlated with Sox4, Sox7, and Sox9 scores. These findings suggested that Sox4, as well as Sox7 and Sox9, may contribute to regulation of EMT/CSC properties to promote development of sarcomatous components in UCSs through transcriptional regulation of the Slug gene by cooperating with the β-catenin/p300 signal pathway.

  7. Terrestrial ecosystems and climatic change

    Energy Technology Data Exchange (ETDEWEB)

    Emanuel, W.R. (Oak Ridge National Lab., TN (USA)); Schimel, D.S. (Colorado State Univ., Fort Collins, CO (USA). Natural Resources Ecology Lab.)

    1990-01-01

    The structure and function of terrestrial ecosystems depend on climate, and in turn, ecosystems influence atmospheric composition and climate. A comprehensive, global model of terrestrial ecosystem dynamics is needed. A hierarchical approach appears advisable given currently available concepts, data, and formalisms. The organization of models can be based on the temporal scales involved. A rapidly responding model describes the processes associated with photosynthesis, including carbon, moisture, and heat exchange with the atmosphere. An intermediate model handles subannual variations that are closely associated with allocation and seasonal changes in productivity and decomposition. A slow response model describes plant growth and succession with associated element cycling over decades and centuries. These three levels of terrestrial models are linked through common specifications of environmental conditions and constrain each other. 58 refs.

  8. Suspected metaldehyde slug bait poisoning in dogs: a retrospective analysis of cases reported to the Veterinary Poisons Information Service.

    Science.gov (United States)

    Bates, N S; Sutton, N M; Campbell, A

    2012-09-29

    A retrospective analysis of telephone enquiries to the Veterinary Poisons Information Service found 772 cases with follow-up concerning suspected metaldehyde slug bait ingestion in dogs between 1985 and 2010. Half the enquiries occurred in the summer months. The amount and strength of the slug bait ingested was rarely known. In 56, cases the quantity consumed was estimated and was on average 229.6 grams of bait. Clinical signs developed in 77.3 per cent of dogs; common signs were convulsions, hypersalivation, twitching, hyperaesthesia, tremor, vomiting, hyperthermia and ataxia. Only 4.6 per cent of dogs developed hepatic changes, and only one developed renal impairment. The average time to onset of signs was 2.9 hours post-ingestion, with 50.3 per cent of dogs developing effects within one hour. Increased muscle activity (twitching, convulsions) lasted on average 15.2 hours. Recovery time was reported in 61 cases and occurred on average at 39.3 hours. Common treatments were gut decontamination, anticonvulsants, anaesthetics and intravenous fluids. Of the dogs that were treated with sedatives, 45.8 per cent required more than one sedative or anaesthetic agent. Methocarbamol was rarely used, probably due to unavailability. The outcome was reported in 762 dogs; 21.7 per cent remained asymptomatic, 61.7 per cent recovered and 16 per cent of dogs died or were euthanased. Where known (only six cases), the fatal dose of bait ranged from 4.2 to 26.7 g/kg (average 11.8 g/kg).

  9. Terrestrial ecosystems and their change

    Science.gov (United States)

    Anatoly Z. Shvidenko; Eric Gustafson; A. David McGuire; Vjacheslav I. Kharuk; Dmitry G. Schepaschenko; Herman H. Shugart; Nadezhda M. Tchebakova; Natalia N. Vygodskaya; Alexander A. Onuchin; Daniel J. Hayes; Ian McCallum; Shamil Maksyutov; Ludmila V. Mukhortova; Amber J. Soja; Luca Belelli-Marchesini; Julia A. Kurbatova; Alexander V. Oltchev; Elena I. Parfenova; Jacquelyn K. Shuman

    2012-01-01

    This chapter considers the current state of Siberian terrestrial ecosystems, their spatial distribution, and major biometric characteristics. Ongoing climate change and the dramatic increase of accompanying anthropogenic pressure provide different but mostly negative impacts on Siberian ecosystems. Future climates of the region may lead to substantial drying on large...

  10. Terrestrial hyperspectral image shadow restoration through fusion with terrestrial lidar

    Science.gov (United States)

    Hartzell, Preston J.; Glennie, Craig L.; Finnegan, David C.; Hauser, Darren L.

    2017-05-01

    Recent advances in remote sensing technology have expanded the acquisition and fusion of active lidar and passive hyperspectral imagery (HSI) from exclusively airborne observations to include terrestrial modalities. In contrast to airborne collection geometry, hyperspectral imagery captured from terrestrial cameras is prone to extensive solar shadowing on vertical surfaces leading to reductions in pixel classification accuracies or outright removal of shadowed areas from subsequent analysis tasks. We demonstrate the use of lidar spatial information for sub-pixel HSI shadow detection and the restoration of shadowed pixel spectra via empirical methods that utilize sunlit and shadowed pixels of similar material composition. We examine the effectiveness of radiometrically calibrated lidar intensity in identifying these similar materials in sun and shade conditions and further evaluate a restoration technique that leverages ratios derived from the overlapping lidar laser and HSI wavelengths. Simulations of multiple lidar wavelengths, i.e., multispectral lidar, indicate the potential for HSI spectral restoration that is independent of the complexity and costs associated with rigorous radiometric transfer models, which have yet to be developed for horizontal-viewing terrestrial HSI sensors. The spectral restoration performance of shadowed HSI pixels is quantified for imagery of a geologic outcrop through improvements in spectral shape, spectral scale, and HSI band correlation.

  11. Mars : a small terrestrial planet

    OpenAIRE

    Mangold, N.; Baratoux, David; Witasse, O.; Encrenaz, T.; Sotin, C.

    2016-01-01

    Mars is characterized by geological landforms familiar to terrestrial geologists. It has a tenuous atmosphere that evolved differently from that of Earth and Venus and a differentiated inner structure. Our knowledge of the structure and evolution of Mars has strongly improved thanks to a huge amount of data of various types (visible and infrared imagery, altimetry, radar, chemistry, etc) acquired by a dozen of missions over the last two decades. In situ data have provided ground truth for rem...

  12. The displacement of oil polymer slug considering of adsorption effects; Deslocamento de oleo por banco de polimero considerando os efeitos de adsorcao

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Priscila M. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Pires, Adolfo P. [Universidade Estadual do Norte Fluminense (UENF), Campos dos Goytacazes, RJ (Brazil)

    2008-07-01

    Among different Enhanced Oil Recovery methods, the injection of chemical solutions plays an important role in mature fields additional recovery. The continuous injection of this kind of fluid would be very expensive, so, the injection of chemical slugs is an attractive alternative to improve the recovery of mature oil fields. Analytical models for 1-D displacement of oil by water with chemical compounds have been developed since the 1960's. This paper presents the 1-D analytical solution of the injection of a chemical slug followed by water drive into an oil reservoir. A flow potential associated with the conservation of water phase is introduced and used as a new independent variable instead of time. This technique permits splitting the system of equations into a thermodynamic system and one transport equation. Another important application of these solutions is the prediction of chemical flooding regardless of the transport properties (relative permeabilities and viscosities). (author)

  13. Model-free optimal anti-slug control of a well-pipeline-riser in the K-Spice/LedaFlow simulator

    Directory of Open Access Journals (Sweden)

    Christer Dalen

    2015-07-01

    Full Text Available Simplified models are developed for a 3-phase well-pipeline-riser and tested together with a high fidelity dynamic model built in K-Spice and LedaFlow. These models are developed from a subspace algorithm, i.e. Deterministic and Stochastic system identification and Realization (DSR, and implemented in a Linear Quadratic optimal Regulator (LQR for stabilizing the slugging regime. We are comparing LQR with PI controller using different performance measures.

  14. MicroRNA-30a increases tight junction protein expression to suppress the epithelial-mesenchymal transition and metastasis by targeting Slug in breast cancer.

    Science.gov (United States)

    Chang, Chia-Wei; Yu, Jyh-Cherng; Hsieh, Yi-Hsien; Yao, Chung-Chin; Chao, Jui-I; Chen, Po-Ming; Hsieh, Hsiao-Yen; Hsiung, Chia-Ni; Chu, Hou-Wei; Shen, Chen-Yang; Cheng, Chun-Wen

    2016-03-29

    The epithelial-to-mesenchymal (EMT) transition is a prerequisite for conferring metastatic potential during tumor progression. microRNA-30a (miR-30a) expression was significantly lower in aggressive breast cancer cell lines compared with non-invasive breast cancer and non-malignant mammary epithelial cell lines. In contrast, miR-30a overexpression reversed the mesenchymal appearance of cancer cells to result in a cobblestone-like epithelial phenotype. We identified Slug, one of the master regulators of EMT, as a target of miR-30a using in silico prediction. Reporter assays indicated that miR-30a could bind to the 3'-untranslted region of Slug mRNA. Furthermore, we linked miR-30a to increased expression of claudins, a family of tight junction transmembrane proteins. An interaction between Slug and E-box in the claudin promoter sequences was reduced upon miR-30a overexpression, further leading to reduction of filopodia formation and decreased invasiveness/metastasis capabilities of breast cancer cells. Consistently, delivery of miR-30a in xenografted mice decreased tumor invasion and migration. In patients with breast cancer, a significantly elevated risk of the miR-30alow/CLDN2low/FSCNhigh genotype was observed, linking to a phenotypic manifestation of larger tumor size, lymph node metastasis, and advanced tumor stage among patients. In conclusion, the miR-30a/Slug axis inhibits mesenchymal tumor development by interfering with metastatic cancer cell programming and may be a potential target for therapy in breast cancer.

  15. Barcoding against a paradox? Combined molecular species delineations reveal multiple cryptic lineages in elusive meiofaunal sea slugs

    Science.gov (United States)

    2012-01-01

    Background Many marine meiofaunal species are reported to have wide distributions, which creates a paradox considering their hypothesized low dispersal abilities. Correlated with this paradox is an especially high taxonomic deficit for meiofauna, partly related to a lower taxonomic effort and partly to a high number of putative cryptic species. Molecular-based species delineation and barcoding approaches have been advocated for meiofaunal biodiversity assessments to speed up description processes and uncover cryptic lineages. However, these approaches show sensitivity to sampling coverage (taxonomic and geographic) and the success rate has never been explored on mesopsammic Mollusca. Results We collected the meiofaunal sea-slug Pontohedyle (Acochlidia, Heterobranchia) from 28 localities worldwide. With a traditional morphological approach, all specimens fall into two morphospecies. However, with a multi-marker genetic approach, we reveal multiple lineages that are reciprocally monophyletic on single and concatenated gene trees in phylogenetic analyses. These lineages are largely concordant with geographical and oceanographic parameters, leading to our primary species hypothesis (PSH). In parallel, we apply four independent methods of molecular based species delineation: General Mixed Yule Coalescent model (GMYC), statistical parsimony, Bayesian Species Delineation (BPP) and Automatic Barcode Gap Discovery (ABGD). The secondary species hypothesis (SSH) is gained by relying only on uncontradicted results of the different approaches (‘minimum consensus approach’), resulting in the discovery of a radiation of (at least) 12 mainly cryptic species, 9 of them new to science, some sympatric and some allopatric with respect to ocean boundaries. However, the meiofaunal paradox still persists in some Pontohedyle species identified here with wide coastal and trans-archipelago distributions. Conclusions Our study confirms extensive, morphologically cryptic diversity among

  16. Development of a slug flow absorber working with ammonia-water mixture: part II - data reduction model for local heat and mass transfer characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H.Y. [Kyushu University, Fukuoka (Japan). Interdisciplinary Graduate School of Engineering Sciences, Department of Energy and Environmental Engineering; Saha, B.B.; Koyama, S. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study

    2003-09-01

    This study deals with the a data reduction model for clarifying experimental results of a counter-current slug flow absorber, working with ammonia-water mixture, for significantly low solution flow rate conditions. The data reduction model to obtain the local heat and mass transfer coefficient on the liquid side is proposed by using the drift flux model to analyze the flow characteristics. The control volume method and heat and mass transfer analogy are employed to solve the combined heat and mass transfer problem. As a result, it is found that the local heat and mass transfer coefficient on the liquid side of the absorber is greatly influenced by the flow pattern. The heat and mass transfer coefficient at the frost flow region is higher than that at the slug flow region due to flow disturbance and random fluctuation. The solution flow rate and gas flow rate have influence on the local heat and mass transfer coefficient at the frost flow region. However, it is insignificant at the slug flow region. (author)

  17. The impact of heavy metals on the grey garden slug, Deroceras reticulatum (Müller): Metal storage, cellular effects and semi-quantitative evaluation of metal toxicity.

    Science.gov (United States)

    Triebskorn, R; Köhler, H R

    1996-01-01

    Laboratory-reared grey garden slugs, Deroceras reticulatum, were exposed to soil and food treated with solutions of three metal salts (CdCl2, ZnCl2, PbCl2) in three environmentally relevant concentrations, each for 21 days. Metal concentrations were determined in the soil, food and slugs by atomic absorption spectrophotometry (AAS). Zinc was localized ultrastructurally in the hepatopancreatic cells by means of energy-filtering transmission electron microscopy (EFTEM). Zinc, and also high amounts of copper, could be detected by electron spectroscopical imaging (ESI) and electron energy loss spectroscopy (EELS) in spherites of the basophilic cells. Ultrastructural responses to metal impact were investigated in two cell types of the hepatopancreas (digestive and basophilic cells) and the cellular responses were found to be dose- and metal-dependent. In order to evaluate the toxicity of the respective metal concentrations to the slugs, the ultrastructural reactions were semi-quantified and summarized as complex reaction patterns of numerous organelles. This novel approach provides a basis for the use of data from standardized tests as a background for risk assessment studies in the field.

  18. Using the Slug Mucosal Irritation Assay to Investigate the Tolerability of Tablet Excipients on Human Skin in the Context of the Use of a Nipple Shield Delivery System.

    Science.gov (United States)

    Kendall, Richard; Lenoir, Joke; Gerrard, Stephen; Scheuerle, Rebekah L; Slater, Nigel K H; Tuleu, Catherine

    2017-04-01

    Neonates are particularly challenging to treat. A novel patented drug delivery device containing a rapidly disintegrating tablet held within a modified nipple shield (NSDS) was designed to deliver medication to infants during breastfeeding. However concerns exist around dermatological nipple tolerability with no pharmaceutical safety assessment guidance to study local tissue tolerance of the nipple and the areola. This is the first Slug Mucosal Irritation (SMI) study to evaluate irritancy potential of GRAS excipients commonly used to manufacture rapidly disintegrating immediate release solid oral dosage form METHODS: Zinc sulphate selected as the antidiarrheal model drug that reduces infant mortality, was blended with functional excipients at traditional levels [microcrystalline cellulose, sodium starch glycolate, croscarmellose sodium, magnesium stearate]. Slugs were exposed to blends slurried in human breast milk to assess their stinging, itching or burning potential, using objective values such as mucus production to categorize irritation potency RESULTS: Presently an in vivo assay, previously validated for prediction of ocular and nasal irritation, was used as an alternative to vertebrate models to anticipate the potential maternal dermatological tolerability issues to NSDS tablet components. The excipients did not elicit irritancy. However, mild irritancy was observed when zinc sulphate was present in blends. These promising good tolerability results support the continued investigation of these excipients within NSDS rapidly disintegrating tablet formulations. Topical local tolerance effects being almost entirely limited to irritation, the slug assay potentially adds to the existing preformulation toolbox, and may sit in between the in vitro and existing in vivo assays.

  19. Terrestrial molluscs of Pemba Island, Zanzibar, Tanzania, and its status as an “oceanic” island

    Directory of Open Access Journals (Sweden)

    Ben Rowson

    2010-11-01

    Full Text Available Pemba is thought to have had a longer and/or stronger history of isolation than its better-known counterpart, Unguja. The extent to which the biota support this hypothesis of greater oceanicity have been debated. Here, Pemba’s terrestrial mollusc (“land-snail” fauna is surveyed and reviewed for the first time. We find at best equivocal evidence for the following hallmarks of greater oceanicity: impoverishment, imbalance, and a high rate of endemism. At least 49 species are present, families are represented in typical proportions, and there are only between two and four island-endemic species - i.e. a 4% to 8% rate of endemism. For land-snails, isolation thus seems to have been short (Pleistocene or, if longer, weak. Nevertheless, Pemba does host endemic and globally rare species. Forty-five percent of the species found, including most of these, is restricted to forest reserves, with Ngezi Forest Reserve particularly rich. A further 45% are able to tolerate the island’s woody cultivated habitats. One new snail species (Cyclophoridae: Cyathopoma and one new slug species (Urocyclidae: Dendrolimax pro tem. are described. New data and illustrations are provided for other taxa.

  20. Slug-flow dynamics with phase change heat transfer in compact heat exchangers with oblique wavy walls

    Science.gov (United States)

    Morimoto, Kenichi; Kinoshita, Hidenori; Matsushita, Ryo; Suzuki, Yuji

    2017-11-01

    With abundance of low-temperature geothermal energy source, small-scale binary-cycle power generation system has gained renewed attention. Although heat exchangers play a dominant role in thermal efficiency and the system size, the optimum design strategy has not been established due to complex flow phenomena and the lack of versatile heat transfer models. In the present study, the concept of oblique wavy walls, with which high j/f factor is achieved by strong secondary flows in single-phase system, is extended to two-phase exchangers. The present analyses are based on evaporation model coupled to a VOF technique, and a train of isolated bubbles is generated under the controlled inlet quality. R245fa is adopted as a low boiling-point working media, and two types of channels are considered with a hydraulic diameter of 4 mm: (i) a straight circular pipe and (ii) a duct with oblique wavy walls. The focus is on slug-flow dynamics with evaporation under small capillary but moderate Weber numbers, where the inertial effect as well as the surface tension is of significance. A possible direction of the change in thermo-physical properties is explored by assuming varied thermal conductivity. Effects of the vortical motions on evaporative heat transfer are highlighted. This work has been supported by the New Energy and Industrial Technology Development Organization (NEDO), Japan.

  1. Retrieving accurate temporal and spatial information about Taylor slug flows from non-invasive NIR photometry measurements

    Science.gov (United States)

    Helmers, Thorben; Thöming, Jorg; Mießner, Ulrich

    2017-11-01

    In this article, we introduce a novel approach to retrieve spatial- and time-resolved Taylor slug flow information from a single non-invasive photometric flow sensor. The presented approach uses disperse phase surface properties to retrieve the instantaneous velocity information from a single sensor's time-scaled signal. For this purpose, a photometric sensor system is simulated using a ray-tracing algorithm to calculate spatially resolved near-infrared transmission signals. At the signal position corresponding to the rear droplet cap, a correlation factor of the droplet's geometric properties is retrieved and used to extract the instantaneous droplet velocity from the real sensor's temporal transmission signal. Furthermore, a correlation for the rear cap geometry based on the a priori known total superficial flow velocity is developed, because the cap curvature is velocity sensitive itself. Our model for velocity derivation is validated, and measurements of a first prototype showcase the capability of the device. Long-term measurements visualize systematic fluctuations in droplet lengths, velocities, and frequencies that could otherwise, without the observation on a larger timescale, have been identified as measurement errors and not systematic phenomenas.

  2. Comparison of Experimental and Computational Fluid Dynamics (CFD Studies of Slug Flow in a Vertical 90° Bend

    Directory of Open Access Journals (Sweden)

    M. Abdulkadir

    2013-12-01

    Full Text Available This paper presents the results of comparison of experimental and CFD studies of slug flow in a vertical 90° bend using validated models. For the experimental part, Electrical Capacitance Tomography (ECT, Wire Mesh Tomography (WMS, and high-speed videos were used to monitor an air-silicone oil mixture flowing in a vertical 90o bend. The ECT probes were mounted before the bend whilst the WMS was positioned either immediately upstream or immediately downstream of the bend. The downstream pipe was maintained horizontal whilst the upstream pipe was maintained vertical. The bend (R/D = 2.3 was made of transparent acrylic resin. Parallel to the experiments, simulations were carried out for same experiment set-up using the commercial software package Star-CD and Star-CCM+. The condition was simulated with the Volume of Fluid (VOF model. The simulation predictions were validated against the experimental data. A reasonably good agreement was observed for the results of the experiment and CFD.

  3. Bubbling bed catalytic hydropyrolysis process utilizinig larger catalyst particles and small biomass particles featuring an anti-slugging reactor

    Science.gov (United States)

    Marker, Terry L.; Felix, Larry G.; Linck, Martin B.; Roberts, Michael J.

    2016-12-06

    This invention relates to a process for thermochemically transforming biomass or other oxygenated feedstocks into high quality liquid hydrocarbon fuels. In particular, a catalytic hydropyrolysis reactor, containing a deep bed of fluidized catalyst particles is utilized to accept particles of biomass or other oxygenated feedstocks that are significantly smaller than the particles of catalyst in the fluidized bed. The reactor features an insert or other structure disposed within the reactor vessel that inhibits slugging of the bed and thereby minimizes attrition of the catalyst. Within the bed, the biomass feedstock is converted into a vapor-phase product, containing hydrocarbon molecules and other process vapors, and an entrained solid char product, which is separated from the vapor stream after the vapor stream has been exhausted from the top of the reactor. When the product vapor stream is cooled to ambient temperatures, a significant proportion of the hydrocarbons in the product vapor stream can be recovered as a liquid stream of hydrophobic hydrocarbons, with properties consistent with those of gasoline, kerosene, and diesel fuel. Separate streams of gasoline, kerosene, and diesel fuel may also be obtained, either via selective condensation of each type of fuel, or via later distillation of the combined hydrocarbon liquid.

  4. Spatial variation in hydraulic conductivity determined by slug tests in the Canadian River alluvium near the Norman Landfill, Norman, Oklahoma

    Science.gov (United States)

    Scholl, Martha A.; Christenson, Scott C.

    1998-01-01

    Slug tests were used to characterize hydraulic conductivity variations at a spatial scale on the order of meters in the alluvial aquifer downgradient of the Norman Landfill. Forty hydraulic conductivity measurements were made, most along a 215-meter flow path transect. Measured hydraulic conductivity, excluding clayey layers, ranged from 8.4 ? 10-7 to 2.8 ? 10-4 meters per second, with a median value of 6.6 ? 10-5 meters per second. The hydraulic conductivity measurements yield a preliminary concept of the permeability structure of the aquifer along this transect. A low hydraulic conductivity silt-clay layer at about 4 meters below the water table and a high hydraulic conductivity layer at the base of the aquifer appear to have the most potential to affect contaminant transport. Specific conductance measurements show the leachate plume along this transect becomes attenuated between 150 and 200 meters downgradient of the landfill, except at the base of the aquifer, where it extends at least 225 meters downgradient of the landfill.

  5. Terrestrial ecosystems under warmer and drier climates

    Science.gov (United States)

    Pan, Y.

    2016-12-01

    Future warmer and drier climates will likely affect many of the world's terrestrial ecosystems. These changes will fundamentally reshape terrestrial systems through their components and across organization levels. However, it is unclear to what extent terrestrial ecosystems would be resilient enough to stay put to increased temperature and water stress by only adjusting carbon fluxes and water balances? And to what extent it would reach the thresholds at which terrestrial ecosystems were forced to alter species compositions and ecosystem structures for adapting to newer climates? The energy balance of terrestrial ecosystems link thermal and water conditions to defines terrestrial carbon processes and feedbacks to climate, which will inevitably change under warmer and drier climates. Recent theoretical studies provide a new framework, suggesting that terrestrial ecosystems were capable of balancing costs of carbon gain and water transport to achieve optimums for functioning and distribution. Such a paradigm is critical for understanding the dynamics of future terrestrial ecosystems under climate changes, and facilitate modeling terrestrial ecosystems which needs generalized principles for formulating ecosystem behaviors. This study aims to review some recent studies that explore responses of terrestrial ecosystems to rather novel climate conditions, such as heat-induced droughts, intending to provide better comprehension of complex carbon-water interactions through plants to an ecosystem, and relevant factors that may alleviate or worsen already deteriorated climates such as elevated CO2 and soil conditions.

  6. Groundwater and Terrestrial Water Storage

    Science.gov (United States)

    Rodell, Matthew; Chambers, Don P.; Famiglietti, James S.

    2014-01-01

    Terrestrial water storage (TWS) comprises groundwater, soil moisture, surface water, snow,and ice. Groundwater typically varies more slowly than the other TWS components because itis not in direct contact with the atmosphere, but often it has a larger range of variability onmultiannual timescales (Rodell and Famiglietti, 2001; Alley et al., 2002). In situ groundwaterdata are only archived and made available by a few countries. However, monthly TWSvariations observed by the Gravity Recovery and Climate Experiment (GRACE; Tapley et al.,2004) satellite mission, which launched in 2002, are a reasonable proxy for unconfinedgroundwater at climatic scales.

  7. Consumer Control of Terrestrial Ecosystems

    Science.gov (United States)

    Frank, D.

    2012-12-01

    More than half of the earth's terrestrial surface is grazed by large herbivores and their effects on plant and soil carbon and nitrogen processes are large and widespread. Yet the large effects of these animals on terrestrial processes have largely been ignored in global change models. This presentation will explore the many pathways that consumers affect short and long time-scale terrestrial nitrogen and carbon processes. Large herbivores influence the quality of soil organic matter and the size of the active (i.e., labile) pool of soil carbon and nitrogen in several ways. Herbivory leads to greater abundance of species producing low quality material in forest and dry grassland, via feeding preferentially on high quality forage, and high quality material in mesic grassland habitat, via the high quality of material that regrows after a plant is grazed. Defoliation stimulates the rate of root exudation that enhances rhizospheric processes and the availability of nitrogen in the plant rhizosphere. Herbivores also change the species composition of mycorrhizae fungal associates that influence plant growth and affect soil structure and the turnover rate of soil carbon. Recent radiocarbon measurements have revealed that herbivores also markedly affect the turnover dynamics of the large pool of old soil carbon. In Yellowstone Park, ungulates slow the mean turnover of the relatively old (i.e., slow and passive) 0 - 20 cm deep soil organic carbon by 350 years in upland, dry grassland and speed up that rate in slope-bottom, mesic grassland by 300 years. This represents a 650 year swing in the turnover period of old soil carbon across the Yellowstone landscape. By comparison, mean turnover time for the old pool of 0 - 10 cm deep soil organic carbon shifts by about 300 years across the steep climatic gradient that includes tropical, temperate, and northern hardwood forest, and tallgrass, shortgrass and desert grassland. This large body of evidence suggests consumers play a

  8. Comparative Climatology of Terrestrial Planets

    Science.gov (United States)

    Mackwell, Stephen J.; Simon-Miller, Amy A.; Harder, Jerald W.; Bullock, Mark A.

    Public awareness of climate change on Earth is currently very high, promoting significant interest in atmospheric processes. We are fortunate to live in an era where it is possible to study the climates of many planets, including our own, using spacecraft and groundbased observations as well as advanced computational power that allows detailed modeling. Planetary atmospheric dynamics and structure are all governed by the same basic physics. Thus differences in the input variables (such as composition, internal structure, and solar radiation) among the known planets provide a broad suite of natural laboratory settings for gaining new understanding of these physical processes and their outcomes. Diverse planetary settings provide insightful comparisons to atmospheric processes and feedbacks on Earth, allowing a greater understanding of the driving forces and external influences on our own planetary climate. They also inform us in our search for habitable environments on planets orbiting distant stars, a topic that was a focus of Exoplanets, the preceding book in the University of Arizona Press Space Sciences Series. Quite naturally, and perhaps inevitably, our fascination with climate is largely driven toward investigating the interplay between the early development of life and the presence of a suitable planetary climate. Our understanding of how habitable planets come to be begins with the worlds closest to home. Venus, Earth, and Mars differ only modestly in their mass and distance from the Sun, yet their current climates could scarcely be more divergent. Our purpose for this book is to set forth the foundations for this emerging science and to bring to the forefront our current understanding of atmospheric formation and climate evolution. Although there is significant comparison to be made to atmospheric processes on nonterrestrial planets in our solar system — the gas and ice giants — here we focus on the terrestrial planets, leaving even broader comparisons

  9. Tectonic evolution of terrestrial planets

    Science.gov (United States)

    Head, J. W.; Solomon, S. C.

    1981-01-01

    The tectonic style of each terrestrial planet, referring to the thickness and division of its lithosphere, can be inferred from surface features and compared to models of planetary thermal history. Factors governing planetary tectonic evolution are planet diameter, chemistry, and external and internal heat sources, all of which determine how a planet generates and rids itself of heat. The earth is distinguished by its distinct, mobile plates, which are recycled into the mantle and show large-scale lateral movements, whereas the moon, Mars, and Mercury are single spherical shells, showing no evidence of destruction and renewal of the lithospheric plates over the latter 80% of their history. Their smaller volume to surface area results in a more rapid cooling, formation, and thickening of the lithosphere. Vertical tectonics, due to lithospheric loading, is controlled by the local thickness and rheology of the lithosphere. Further studies of Venus, which displays both the craterlike surface features of the one-plate planets, and the rifts and plateaus of earth, may indicate which factors are most important in controlling the tectonic evolution of terrestrial planets.

  10. The Laboratory for Terrestrial Physics

    Science.gov (United States)

    2003-01-01

    The Laboratory for Terrestrial Physics is dedicated to the advancement of knowledge in Earth and planetary science, by conducting innovative research using space technology. The Laboratory's mission and activities support the work and new initiatives at NASA's Goddard Space Flight Center (GSFC). The Laboratory's success contributes to the Earth Science Directorate as a national resource for studies of Earth from Space. The Laboratory is part of the Earth Science Directorate based at the GSFC in Greenbelt, MD. The Directorate itself is comprised of the Global Change Data Center (GCDC), the Space Data and Computing Division (SDCD), and four science Laboratories, including Laboratory for Terrestrial Physics, Laboratory for Atmospheres, and Laboratory for Hydrospheric Processes all in Greenbelt, MD. The fourth research organization, Goddard Institute for Space Studies (GISS), is in New York, NY. Relevant to NASA's Strategic Plan, the Laboratory ensures that all work undertaken and completed is within the vision of GSFC. The philosophy of the Laboratory is to balance the completion of near term goals, while building on the Laboratory's achievements as a foundation for the scientific challenges in the future.

  11. Riparian vegetation in the alpine connectome: Terrestrial-aquatic and terrestrial-terrestrial interactions.

    Science.gov (United States)

    Zaharescu, Dragos G; Palanca-Soler, Antonio; Hooda, Peter S; Tanase, Catalin; Burghelea, Carmen I; Lester, Richard N

    2017-12-01

    Alpine regions are under increased attention worldwide for their critical role in early biogeochemical cycles, their high sensitivity to environmental change, and as repositories of natural resources of high quality. Their riparian ecosystems, at the interface between aquatic and terrestrial environments, play important geochemical functions in the watershed and are biodiversity hotspots, despite a harsh climate and topographic setting. With climate change rapidly affecting the alpine biome, we still lack a comprehensive understanding of the extent of interactions between riparian surface, lake and catchment environments. A total of 189 glacial - origin lakes were surveyed in the Central Pyrenees to test how key elements of the lake and terrestrial environments interact at different scales to shape riparian plant composition. Secondly, we evaluated how underlying ecotope features drive the formation of natural communities potentially sensitive to environmental change and assessed their habitat distribution. At the macroscale, vegetation composition responded to pan-climatic gradients altitude and latitude, which captured in a narrow geographic area the transition between large European climatic zones. Hydrodynamics was the main catchment-scale factor connecting riparian vegetation with major water fluxes, followed by topography and geomorphology. Lake sediment Mg and Pb, and water Mn and Fe contents reflected local influences from mafic bedrock and soil water saturation. Community analysis identified four keystone ecosystems: (i) damp ecotone, (ii) snow bed-silicate bedrock, (iii) wet heath, and (iv) calcareous substrate. These communities and their connections with ecotope elements could be at risk from a number of environmental change factors including warmer seasons, snow line and lowland species advancement, increased nutrient/metal input and water level fluctuations. The results imply important natural terrestrial-aquatic linkages in the riparian environment

  12. Ocean barriers and glaciation: evidence for explosive radiation of mitochondrial lineages in the Antarctic sea slug Doris kerguelenensis (Mollusca, Nudibranchia).

    Science.gov (United States)

    Wilson, Nerida G; Schrödl, M; Halanych, Kenneth M

    2009-03-01

    Strong currents and deep passages of water can be barriers for larval dispersal of continental marine animals, but potential effects on direct developers are under-investigated. We examined the genetic structure of Doris kerguelenensis, a directly developing sea slug that occurs across the Drake Passage, the body of water separating Antarctica from South America. We found deep mitochondrial divergences within populations on both sides of the Drake Passage, and South American animals formed multiple sister-group relationships with Antarctic animals. A generalised molecular clock suggested these trans-Drake pairs diverged during the Pliocene–Pleistocene, after the formation of the Drake Passage. Statistical parsimony methods recovered 29 separate haplotype networks (many sympatric) that likely correlate with allopatric events caused by repeated glacial cycles. Data from 16S were congruent but more conserved than COI, and the estimated ancestral 16S haplotype was widespread. The marked difference in the substitution rates between these two mitochondrial genes results in different estimates of connectivity. Demographic analyses on networks revealed some evidence for selection and expanding populations. Contrasting with the Northern Hemisphere, glaciation in Antarctica appears to have increased rather than reduced genetic diversity. This suggests orbitally forced range dynamics based on Northern Hemisphere phylogeography do not hold for Antarctica. The diverse lineages found in D. kerguelenensis point towards a recent, explosive radiation, likely reflecting multiple refuges during glaciation events, combined with limited subsequent dispersal. Whether recognised as cryptic species or not, genetic diversity in Antarctic marine invertebrates appears higher than expected from morphological analyses, and supports the Antarctic biodiversity pump phenomenon.

  13. Do earthworms help to sustain the slug predator Pterostichus melanarius (Coleoptera: carabidae) within crops? Investigations using monoclonal antibodies.

    Science.gov (United States)

    Symondson, W O; Glen, D M; Erickson, M L; Liddell, J E; Langdon, C J

    2000-09-01

    Earthworms provide a major potential source of alternative food for polyphagous predators, such as carabid beetles, that are natural enemies of slugs, aphids and other agricultural pests. Non-pest prey may foster larger numbers of natural enemies, which then help to control pests, or alternatively may help to divert the predators away from pest control. An earthworm-specific monoclonal antibody was developed to study carabid-earthworm interactions in the field and assess the role of earthworms as alternative prey. The antibody could identify as little at 7 ng of earthworm protein in an ELISA, and could detect earthworm remains in the foregut of the carabid beetle Pterostichus melanarius for 64 h after consumption. Thirty-six per cent of field-collected beetles contained earthworm remains. Quantities of earthworm proteins in the beetle foreguts were negatively related to total foregut biomass, suggesting that earthworm consumption increased as total prey availability declined. There was also a negative relationship between foregut biomass and beetle numbers, but both quantities and concentrations of earthworm proteins in beetle foreguts were positively related to beetle numbers. This suggests that as beetle activity-density increased, total prey availability declined, or, as prey availability declined, beetles spent more time searching. In these circumstances, beetles fed to a greater extent on earthworms, an acceptable but nonpreferred food item. Earthworms may, therefore, provide an ideal alternative prey for P. melanarius, helping to sustain it when pest numbers are low but allowing it to perform a 'lying-in-wait' strategy, ready to switch back to feeding on pests when they become available.

  14. Terrestrial pathways of radionuclide particulates

    Energy Technology Data Exchange (ETDEWEB)

    Boone, F.W. (Allied-General Nuclear Services, Barnwell, SC (USA)); Ng, Y.C. (California Univ., Livermore (USA). Lawrence Livermore National Lab.); Palms, J.M. (Emory Univ., Atlanta, GA (USA))

    1981-11-01

    Formulations are developed for computing potential human intake of 13 radionuclides via the terrestrial food chains. The formulations are an extension of the NRC methodology. Specific regional crop and livestock transfer and fractional distribution data from the southern part of the U.S.A. are provided and used in the computation of comparative values with those computed by means of USNRC Regulatory Guide 1.109 formulations. In the development of the model, emphasis was also placed on identifying the various time-delay compartments of the food chains and accounting for all of the activity initially deposited. For all radionuclides considered, except /sup 137/Cs, the new formulations predict lower potential intakes from the total of all food chains combined than do the comparable Regulatory Guide formulations by as much as a factor of 40. For /sup 137/Cs the new formulations predict 10% higher potential intakes.

  15. Terrestrial atmosphere, water and astrobiology

    Directory of Open Access Journals (Sweden)

    Coradini M.

    2010-12-01

    Full Text Available Primitive life, defined as a chemical system capable to transfer its molecular information via self-replication and also capable to evolve, originated about 4 billion years ago from the processing of organic molecules by liquid water. Terrestrial atmosphere played a key role in the process by allowing the permanent presence of liquid water and by participating in the production of carbon-based molecules. Water molecules exhibit specific properties mainly due to a dense network of hydrogen bonds. The carbon-based molecules were either home made in the atmosphere and/or in submarine hydrothermal systems or delivered by meteorites and micrometeorites. The search for possible places beyond the earth where the trilogy atmosphere/water/life could exist is the main objective of astrobiology. Within the Solar System, exploration missions are dedicated to Mars, Europa, Titan and the icy bodies. The discovery of several hundreds of extrasolar planets opens the quest to the whole Milky Way.

  16. Extreme solar-terrestrial events

    Science.gov (United States)

    Dal Lago, A.; Antunes Vieira, L. E.; Echer, E.; Balmaceda, L. A.; Rockenbach, M.; Gonzalez, W. D.

    2017-10-01

    Extreme solar-terrestrial events are those in which very energetic solar ejections hit the earth?s magnetosphere, causing intense energization of the earth?s ring current. Statistically, their occurrence is approximately once per Gleissberg solar cycle (70-100yrs). The solar transient occurred on July, 23rd (2012) was potentially one of such extreme events. The associated coronal mass ejection (CME), however, was not ejected towards the earth. Instead, it hit the STEREO A spacecraft, located 120 degrees away from the Sun-Earth line. Estimates of the geoeffectiveness of such a CME point to a scenario of extreme Space Weather conditions. In terms of the ring current energization, as measured by the Disturbance Storm-Time index (Dst), had this CME hit the Earth, it would have caused the strongest geomagnetic storm in space era.

  17. Crenarchaeota colonize terrestrial plant roots.

    Science.gov (United States)

    Simon, H M; Dodsworth, J A; Goodman, R M

    2000-10-01

    Microorganisms that colonize plant roots are recruited from, and in turn contribute substantially to, the vast and virtually uncharacterized phylogenetic diversity of soil microbiota. The diverse, but poorly understood, microorganisms that colonize plant roots mediate mineral transformations and nutrient cycles that are central to biosphere functioning. Here, we report the results of epifluorescence microscopy and culture-independent recovery of small subunit (SSU) ribosomal RNA (rRNA) gene sequences showing that members of a previously reported clade of soil Crenarchaeota colonize both young and senescent plant roots at an unexpectedly high frequency, and are particularly abundant on the latter. Our results indicate that non-thermophilic members of the Archaea inhabit an important terrestrial niche on earth and direct attention to the need for studies that will determine their possible roles in mediating root biology.

  18. Hepatoprotective and Antioxidant Activities of Tribulus Terrestris

    NARCIS (Netherlands)

    Harraz, Fathalla M; Ghazy, Nabila M; Hammoda, Hala M; Nafeaa, Abeer A.; Abdallah, Ingy I.

    2015-01-01

    Tribulus terrestris L. has been used in folk medicine throughout history. The present study examined the acute toxicity of the total ethanolic extract of T. Terrestris followed by investigation of the hepatoprotective activity of the total ethanolic extract and different fractions of the aerial

  19. Chemokine (CC motif) ligand 18 upregulates Slug expression to promote stem-cell like features by activating the mammalian target of rapamycin pathway in oral squamous cell carcinoma.

    Science.gov (United States)

    Wang, Hongfei; Liang, Xueyi; Li, Mianxiang; Tao, Xiaoan; Tai, Shanshan; Fan, Zhaona; Wang, Zhi; Cheng, Bin; Xia, Juan

    2017-08-01

    Chemokine (CC motif) ligand 18 (CCL18) is involved in remodeling of the tumor microenvironment and plays critical roles in oncogenesis, invasiveness, and metastasis. We previously investigated the overexpression of CCL18 in primary oral squamous cell carcinoma (OSCC) tissues and its association with advanced clinical stage in OSCC patients. However, the underlying mechanisms of this CCL18-derived activity remains unidentified. This study showed exogenous CCL18 increased cell migration and invasion and induced cell epithelial-mesenchymal transition (EMT), and that E-cadherin, an epithelial marker, decreased and N-cadherin, a mesenchymal marker, increased, compared to negative control in OSCC cells. Furthermore, we detected that CCL18 induced the acquisition of cancer stem(-like) cell characteristics in oral cancer cells, but also found a significantly positive correlation between the expression of CCL18 and Bmi-1 (P formation ability was observably enhanced when cells were continually exposed to high levels of CCL18. Moreover, CCL18 upregulated Slug expression by stimulating the mammalian target of rapamycin (mTOR) signaling pathway in OSCC cell lines. Inhibition of the mTOR pathway by INK128, or Slug knockdown by RNA interference, reversed CCL18-induced EMT and the stemness response at both molecular and functional levels. In conclusion, our data suggested that CCL18 upregulated Slug expression to promote EMT and stem cell-like features by activating the mTOR pathway in oral cancer. These findings provide new potential targets for the early diagnosis and treatment of OSCC. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

  20. Insignificant solar-terrestrial triggering of earthquakes

    Science.gov (United States)

    Love, Jeffrey J.; Thomas, Jeremy N.

    2013-01-01

    We examine the claim that solar-terrestrial interaction, as measured by sunspots, solar wind velocity, and geomagnetic activity, might play a role in triggering earthquakes. We count the number of earthquakes having magnitudes that exceed chosen thresholds in calendar years, months, and days, and we order these counts by the corresponding rank of annual, monthly, and daily averages of the solar-terrestrial variables. We measure the statistical significance of the difference between the earthquake-number distributions below and above the median of the solar-terrestrial averages by χ2 and Student's t tests. Across a range of earthquake magnitude thresholds, we find no consistent and statistically significant distributional differences. We also introduce time lags between the solar-terrestrial variables and the number of earthquakes, but again no statistically significant distributional difference is found. We cannot reject the null hypothesis of no solar-terrestrial triggering of earthquakes.

  1. Numerical and experimental study of the slug-flow regime in a mixture of castor and paraffin oils in a T-type microchannel

    Science.gov (United States)

    Minakov, A. V.; Shebeleva, A. A.; Yagodnitsyna, A. A.; Kovalev, A. V.; Bilsky, A. V.

    2017-09-01

    The slow-flug regime in a mixture of castor and paraffin oils in a T-type microchannel with crosssectional dimensions of 200 × 400 μm has been studied by numerical and experimental methods. The domain of existence of the slow-flug regime in this system has been determined. Dependence of the paraffin-oil slug length on the ratio of flow rates of the mixture components is established. Comparison of the calculated and experimental data shows their good agreement.

  2. Slug inhibits the proliferation and tumor formation of human cervical cancer cells by up-regulating the p21/p27 proteins and down-regulating the activity of the Wnt/β-catenin signaling pathway via the trans-suppression Akt1/p-Akt1 expression.

    Science.gov (United States)

    Cui, Nan; Yang, Wen-Ting; Zheng, Peng-Sheng

    2016-05-03

    Slug (Snai2) has been demonstrated to act as an oncogene or tumor suppressor in different human cancers, but the function of Slug in cervical cancer remains poorly understood. In this study, we demonstrated that Slug could suppress the proliferation of cervical cancer cells in vitro and tumor formation in vivo. Further experiments found that Slug could trans-suppress the expression of Akt1/p-Akt1 by binding to E-box motifs in the promoter of the Akt1 gene and then inhibit the cell proliferation and tumor formation of cervical cancer cells by up-regulating p21/p27 and/or down-regulating the activity of the Wnt/β-catenin signaling pathway. Therefore, Slug acts as a tumor suppressor during cervical carcinogenesis.

  3. Does terrestrial epidemiology apply to marine systems?

    Science.gov (United States)

    McCallum, Hamish I.; Kuris, Armand M.; Harvell, C. Drew; Lafferty, Kevin D.; Smith, Garriet W.; Porter, James

    2004-01-01

    Most of epidemiological theory has been developed for terrestrial systems, but the significance of disease in the ocean is now being recognized. However, the extent to which terrestrial epidemiology can be directly transferred to marine systems is uncertain. Many broad types of disease-causing organism occur both on land and in the sea, and it is clear that some emergent disease problems in marine environments are caused by pathogens moving from terrestrial to marine systems. However, marine systems are qualitatively different from terrestrial environments, and these differences affect the application of modelling and management approaches that have been developed for terrestrial systems. Phyla and body plans are more diverse in marine environments and marine organisms have different life histories and probably different disease transmission modes than many of their terrestrial counterparts. Marine populations are typically more open than terrestrial ones, with the potential for long-distance dispersal of larvae. Potentially, this might enable unusually rapid propagation of epidemics in marine systems, and there are several examples of this. Taken together, these differences will require the development of new approaches to modelling and control of infectious disease in the ocean.

  4. A molecular palaeobiological exploration of arthropod terrestrialization.

    Science.gov (United States)

    Lozano-Fernandez, Jesus; Carton, Robert; Tanner, Alastair R; Puttick, Mark N; Blaxter, Mark; Vinther, Jakob; Olesen, Jørgen; Giribet, Gonzalo; Edgecombe, Gregory D; Pisani, Davide

    2016-07-19

    Understanding animal terrestrialization, the process through which animals colonized the land, is crucial to clarify extant biodiversity and biological adaptation. Arthropoda (insects, spiders, centipedes and their allies) represent the largest majority of terrestrial biodiversity. Here we implemented a molecular palaeobiological approach, merging molecular and fossil evidence, to elucidate the deepest history of the terrestrial arthropods. We focused on the three independent, Palaeozoic arthropod terrestrialization events (those of Myriapoda, Hexapoda and Arachnida) and showed that a marine route to the colonization of land is the most likely scenario. Molecular clock analyses confirmed an origin for the three terrestrial lineages bracketed between the Cambrian and the Silurian. While molecular divergence times for Arachnida are consistent with the fossil record, Myriapoda are inferred to have colonized land earlier, substantially predating trace or body fossil evidence. An estimated origin of myriapods by the Early Cambrian precedes the appearance of embryophytes and perhaps even terrestrial fungi, raising the possibility that terrestrialization had independent origins in crown-group myriapod lineages, consistent with morphological arguments for convergence in tracheal systems.This article is part of the themed issue 'Dating species divergences using rocks and clocks'. © 2016 The Authors.

  5. A molecular palaeobiological exploration of arthropod terrestrialization

    Science.gov (United States)

    Carton, Robert; Edgecombe, Gregory D.

    2016-01-01

    Understanding animal terrestrialization, the process through which animals colonized the land, is crucial to clarify extant biodiversity and biological adaptation. Arthropoda (insects, spiders, centipedes and their allies) represent the largest majority of terrestrial biodiversity. Here we implemented a molecular palaeobiological approach, merging molecular and fossil evidence, to elucidate the deepest history of the terrestrial arthropods. We focused on the three independent, Palaeozoic arthropod terrestrialization events (those of Myriapoda, Hexapoda and Arachnida) and showed that a marine route to the colonization of land is the most likely scenario. Molecular clock analyses confirmed an origin for the three terrestrial lineages bracketed between the Cambrian and the Silurian. While molecular divergence times for Arachnida are consistent with the fossil record, Myriapoda are inferred to have colonized land earlier, substantially predating trace or body fossil evidence. An estimated origin of myriapods by the Early Cambrian precedes the appearance of embryophytes and perhaps even terrestrial fungi, raising the possibility that terrestrialization had independent origins in crown-group myriapod lineages, consistent with morphological arguments for convergence in tracheal systems. This article is part of the themed issue ‘Dating species divergences using rocks and clocks’. PMID:27325830

  6. Mars: a small terrestrial planet

    Science.gov (United States)

    Mangold, N.; Baratoux, D.; Witasse, O.; Encrenaz, T.; Sotin, C.

    2016-11-01

    Mars is characterized by geological landforms familiar to terrestrial geologists. It has a tenuous atmosphere that evolved differently from that of Earth and Venus and a differentiated inner structure. Our knowledge of the structure and evolution of Mars has strongly improved thanks to a huge amount of data of various types (visible and infrared imagery, altimetry, radar, chemistry, etc) acquired by a dozen of missions over the last two decades. In situ data have provided ground truth for remote-sensing data and have opened a new era in the study of Mars geology. While large sections of Mars science have made progress and new topics have emerged, a major question in Mars exploration—the possibility of past or present life—is still unsolved. Without entering into the debate around the presence of life traces, our review develops various topics of Mars science to help the search of life on Mars, building on the most recent discoveries, going from the exosphere to the interior structure, from the magmatic evolution to the currently active processes, including the fate of volatiles and especially liquid water.

  7. Ocorrência e controle de lesmas do gênero Omalonyx (Gastropoda, Succineidae, pragas de capim-elefante Pennisetum purpureum (Poaceae em Rio Preto da Eva, Amazonas Occurrence and control of Omalonyx slugs (Gastropoda, Succineidae, pests of the elephant-grass Pennisetum purpureum (Poaceae in Rio Preto da Eva, Amazonas

    Directory of Open Access Journals (Sweden)

    Marcos Vinicius Bastos Garcia

    2012-06-01

    Full Text Available Lesmas do gênero Omalonyx d'Orbigny, 1837 são hermafroditas, herbívoras, de distribuição neotropical e vivem em plantas aquáticas, nas demais vegetações adjacentes e em solo úmido próximo a ambientes de água doce. No presente trabalho reporta-se a ocorrência atípica de O. pattersonae Tillier, 1981 e de Omalonyx sp. em área de terra firme, distante de ambiente aquático. Estas espécies aqui reportadas são simpátricas e devido à alta densidade populacional e prejuízos causados às folhas do capim-elefante Pennisetum purpureum Schumach, são caracterizadas como pragas agrícolas. No período da noite as lesmas se alimentavam das folhas do capim elefante e durante o dia permaneciam escondidas na base do caule, próximo a superfície úmida do solo. A aplicação de cal hidratada sobre agregados de indivíduos de Omalonyx spp foi um método efetivo para o controle das populações. As alterações ambientais dos ecossistemas amazônicos para uso agrícola e/ou urbanização tem promovido o aumento populacional de espécies que se adaptam a novos habitats e geralmente se tornam pragas de difícil controle.Slugs of the genus Omalonyx d'Orbigny, 1837 are hermaphrodites, herbivorous, distributed on Neotropical regions, living on aquatic plants, moist soil and terrestrial vegetation close to freshwater systems. The present paper reports the atypical occurrence of O. pattersonae Tillier, 1981 and Omalonyx sp. in an upland area far from any aquatic environment. Both species reported here are sympatric and due to the high populations density and damages caused on leaves of elephant-grass Pennisetum purpureum Schumach, they are recognized as agricultural pests. During the night, the slugs feed on the grass leaves and at the daylight they stayed hidden in the base of stems, near the moist soil surface. The use of hydrated lime distributed over the aggregations of Omalonyx spp. showed to be an effective method to control the populations. The

  8. A molecular palaeobiological exploration of arthropod terrestrialization

    DEFF Research Database (Denmark)

    Lozano-Fernandez, Jesus; Carton, Robert; Tanner, Alastair R.

    2016-01-01

    amolecular palaeobiological approach, merging molecular and fossil evidence, to elucidate the deepest history of the terrestrial arthropods. We focused on the three independent, Palaeozoic arthropod terrestrialization events (those of Myriapoda, Hexapoda and Arachnida) and showed that a marine route...... to the colonization of land is the most likely scenario.Molecular clock analyses confirmed an origin for the three terrestrial lineages bracketed between the Cambrian and the Silurian. While molecular divergence times for Arachnida are consistent with the fossil record,Myriapoda are inferred to have colonized land...

  9. Testing the snake-detection hypothesis: larger early posterior negativity in humans to pictures of snakes than to pictures of other reptiles, spiders and slugs.

    Science.gov (United States)

    Van Strien, Jan W; Franken, Ingmar H A; Huijding, Jorg

    2014-01-01

    According to the snake detection hypothesis (Isbell, 2006), fear specifically of snakes may have pushed evolutionary changes in the primate visual system allowing pre-attentional visual detection of fearful stimuli. A previous study demonstrated that snake pictures, when compared to spiders or bird pictures, draw more early attention as reflected by larger early posterior negativity (EPN). Here we report two studies that further tested the snake detection hypothesis. In Study 1, we tested whether the enlarged EPN is specific for snakes or also generalizes to other reptiles. Twenty-four healthy, non-phobic women watched the random rapid serial presentation of snake, crocodile, and turtle pictures. The EPN was scored as the mean activity at occipital electrodes (PO3, O1, Oz, PO4, O2) in the 225-300 ms time window after picture onset. The EPN was significantly larger for snake pictures than for pictures of the other reptiles. In Study 2, we tested whether disgust plays a role in the modulation of the EPN and whether preferential processing of snakes also can be found in men. 12 men and 12 women watched snake, spider, and slug pictures. Both men and women exhibited the largest EPN amplitudes to snake pictures, intermediate amplitudes to spider pictures and the smallest amplitudes to slug pictures. Disgust ratings were not associated with EPN amplitudes. The results replicate previous findings and suggest that ancestral priorities modulate the early capture of visual attention.

  10. Shallow water sea slugs (Gastropoda: Heterobranchia) from the northwestern coast of the Sea of Japan, north of Peter the Great Bay, Russia.

    Science.gov (United States)

    Chichvarkhin, Anton

    2016-01-01

    The coast of northern Primorye region, north of Peter the Great Bay has been sparsely studied in regards to its molluscan fauna, with just a few works reviewing the distribution of local mollusks. This work presents a survey of the shallow water heterobranch sea slugs currently occurring around Kievka Bay to Oprichnik Bay, Russia. Thirty-nine species of sea slugs were found in this study and the new species Cadlina olgae sp. nov., described herein. Most (24) of the species occurring in the area have widespread ranges in the northern Pacific Ocean. The eight species are endemic for the Sea of Japan and adjacent part of the Sea of Okhotsk. Seven other occur also in northern Atlantic and Arctic waters. Thirteen found species are not known from Peter the Great Bay but known from adjacent northern Pacific waters. The finding of a previously undescribed species emphasizes the need of further surveys, particularly in subtidal and deeper waters, in order to improve the knowledge on this neglected fauna in Primorye.

  11. Possible climates on terrestrial exoplanets.

    Science.gov (United States)

    Forget, F; Leconte, J

    2014-04-28

    What kind of environment may exist on terrestrial planets around other stars? In spite of the lack of direct observations, it may not be premature to speculate on exoplanetary climates, for instance, to optimize future telescopic observations or to assess the probability of habitable worlds. To begin with, climate primarily depends on (i) the atmospheric composition and the volatile inventory; (ii) the incident stellar flux; and (iii) the tidal evolution of the planetary spin, which can notably lock a planet with a permanent night side. The atmospheric composition and mass depends on complex processes, which are difficult to model: origins of volatiles, atmospheric escape, geochemistry, photochemistry, etc. We discuss physical constraints, which can help us to speculate on the possible type of atmosphere, depending on the planet size, its final distance for its star and the star type. Assuming that the atmosphere is known, the possible climates can be explored using global climate models analogous to the ones developed to simulate the Earth as well as the other telluric atmospheres in the solar system. Our experience with Mars, Titan and Venus suggests that realistic climate simulators can be developed by combining components, such as a 'dynamical core', a radiative transfer solver, a parametrization of subgrid-scale turbulence and convection, a thermal ground model and a volatile phase change code. On this basis, we can aspire to build reliable climate predictors for exoplanets. However, whatever the accuracy of the models, predicting the actual climate regime on a specific planet will remain challenging because climate systems are affected by strong positive feedbacks. They can drive planets with very similar forcing and volatile inventory to completely different states. For instance, the coupling among temperature, volatile phase changes and radiative properties results in instabilities, such as runaway glaciations and runaway greenhouse effect.

  12. Terrestrial Ecosystems of the Conterminous United States

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) modeled the distribution of terrestrial ecosystems for the contiguous United States using a standardized, deductive approach to...

  13. Terrestrial Radiodetermination Potential Users and Their Requirements

    Science.gov (United States)

    1976-07-01

    The report summarizes information gathered during a preliminary study of the application of electronic techniques to geographical position determination on land and on inland waterways. Systems incorporating such techniques have been called terrestri...

  14. Transfer of terrestrial technology for lunar mining

    Science.gov (United States)

    Hall, Robert A.; Green, Patricia A.

    The functions, operational procedures, and major items of equipment that comprise the terrestrial mining process are characterized. These data are used to synthesize a similar activity on the lunar surface. Functions, operations, and types of equipment that can be suitably transferred to lunar operation are identified. Shortfalls, enhancements, and technology development needs are described. The lunar mining process and what is required to adapt terrestrial equipment are highlighted. It is concluded that translation of terrestrial mining equipment and operational processes to perform similar functions on the lunar surface is practical. Adequate attention must be given to the harsh environment and logistical constraints of the lunar setting. By using earth-based equipment as a forcing function, near- and long-term benefits are derived (i.e., improved terrestrial mining in the near term vis-a-vis commercial production of helium-3 in the long term.

  15. The Circumpolar Biodiversity Monitoring Program Terrestrial Plan

    DEFF Research Database (Denmark)

    Christensen, Tom; Payne, J.; Doyle, M.

    The Conservation of Arctic Flora and Fauna (CAFF), the biodiversity working group of the Arctic Council, established the Circumpolar Biodiversity Monitoring Program (CBMP) to address the need for coordinated and standardized monitoring of Arctic environments in terrestrial, marine, freshwater...... and coastal environments. The CBMP Terrestrial Plan is a framework to focus and coordinate monitoring of terrestrial biodiversity across the Arctic. The goal of the plan is to improve the collective ability of Arctic traditional knowledge (TK) holders, northern communities, and scientists to detect......, understand and report on long-term change in Arctic terrestrial ecosystems and biodiversity, and to identify knowledge gaps and priorities. This poster will outline the key management questions the plan aims to address and the proposed nested, multi-scaled approach linking targeted, research based monitoring...

  16. The circumpolar biodiversity monitoring program - Terrestrial plan

    DEFF Research Database (Denmark)

    Christensen, Tom; Payne, J.; Doyle, M.

    and attributes to monitor in the plan related to soil invertebrates. Focal Ecosystem Components (FECs) of the soil decomposer system include the soil living invertebrates such as microarthropods, enchytraeids and earthworms and the functions performed by microorganisms such as nitrification, decomposition......The Circumpolar Biodiversity Monitoring Program, CBMP, Terrestrial Plan, www.caff.is/terrestrial, is a framework to focus and coordinate monitoring of terrestrial biodiversity across the Arctic. The goal of the plan is to improve the collective ability of Arctic traditional knowledge (TK) holders......, northern communities, and scientists to detect, understand and report on long-term change in Arctic terrestrial ecosystems and biodiversity. This presentation will outline the key management questions the plan aims to address and the proposed nested, multi-scaled approach linking targeted, research based...

  17. SLUG HANDLING DEVICES

    Science.gov (United States)

    Gentry, J.R.

    1958-09-16

    A device is described for handling fuel elements of a neutronic reactor. The device consists of two concentric telescoped contalners that may fit about the fuel element. A number of ratchet members, equally spaced about the entrance to the containers, are pivoted on the inner container and spring biased to the outer container so thnt they are forced to hear against and hold the fuel element, the weight of which tends to force the ratchets tighter against the fuel element. The ratchets are released from their hold by raising the inner container relative to the outer memeber. This device reduces the radiation hazard to the personnel handling the fuel elements.

  18. Groundwater and Terrestrial Water Storage

    Science.gov (United States)

    Rodell, Matthew; Chambers, Don P.; Famiglietti, James S.

    2011-01-01

    Most people think of groundwater as a resource, but it is also a useful indicator of climate variability and human impacts on the environment. Groundwater storage varies slowly relative to other non-frozen components of the water cycle, encapsulating long period variations and trends in surface meteorology. On seasonal to interannual timescales, groundwater is as dynamic as soil moisture, and it has been shown that groundwater storage changes have contributed to sea level variations. Groundwater monitoring well measurements are too sporadic and poorly assembled outside of the United States and a few other nations to permit direct global assessment of groundwater variability. However, observational estimates of terrestrial water storage (TWS) variations from the GRACE satellites largely represent groundwater storage variations on an interannual basis, save for high latitude/altitude (dominated by snow and ice) and wet tropical (surface water) regions. A figure maps changes in mean annual TWS from 2009 to 2010, based on GRACE, reflecting hydroclimatic conditions in 2010. Severe droughts impacted Russia and the Amazon, and drier than normal weather also affected the Indochinese peninsula, parts of central and southern Africa, and western Australia. Groundwater depletion continued in northern India, while heavy rains in California helped to replenish aquifers that have been depleted by drought and withdrawals for irrigation, though they are still below normal levels. Droughts in northern Argentina and western China similarly abated. Wet weather raised aquifer levels broadly across western Europe. Rains in eastern Australia caused flooding to the north and helped to mitigate a decade long drought in the south. Significant reductions in TWS seen in the coast of Alaska and the Patagonian Andes represent ongoing glacier melt, not groundwater depletion. Figures plot time series of zonal mean and global GRACE derived non-seasonal TWS anomalies (deviation from the mean of

  19. INFLUENCE OF SOFT SQUEEZING ON THE DEGREE OF AXIAL CHEMICAL HETEROGENEITY AT PRODUCTION OF CONTINUOUSLY CASTED SLUGS. Message 1. Analysis of existing methods of production realization and calculation of regimes of soft squeezing

    Directory of Open Access Journals (Sweden)

    Ju. A. Samojlovich

    2008-01-01

    Full Text Available The methods of influence on quality of uninterruptedlycasted slug from the point of  view of  the axial chemical heterogeneity depression are considered, at the same time high emphasis is placed on use of  soft squeezing method.

  20. Microplastics in the terrestrial ecosystem: Implications for Lumbricus terrestris (Oligochaeta, Lumbricidae)

    NARCIS (Netherlands)

    Huerta Lwanga, Esperanza; Gertsen, H.F.; Gooren, H.; Peters, P.D.; Salanki, T.E.; Ploeg, van der M.J.C.; Besseling, E.; Koelmans, A.A.; Geissen, V.

    2016-01-01

    Plastic debris is widespread in the environment, but information on the effects of microplastics on terrestrial fauna is completely lacking. Here, we studied the survival and fitness of the earthworm Lumbricus terrestris (Oligochaeta, Lumbricidae) exposed to microplastics (Polyethylene, <150 μm)

  1. Numerical simulations for terrestrial planets formation

    Directory of Open Access Journals (Sweden)

    Ji J.

    2011-07-01

    Full Text Available We investigate the formation of terrestrial planets in the late stage of planetary formation using two-planet model. At that time, the protostar has formed for about 3 Myr and the gas disk has dissipated. In the model, the perturbations from Jupiter and Saturn are considered. We also consider variations of the mass of outer planet, and the initial eccentricities and inclinations of embryos and planetesimals. Our results show that, terrestrial planets are formed in 50 Myr, and the accretion rate is about 60%–80%. In each simulation, 3–4 terrestrial planets are formed inside “Jupiter” with masses of 0.15–3.6 M⊕. In the 0.5–4 AU, when the eccentricities of planetesimals are excited, planetesimals are able to accrete material from wide radial direction. The plenty of water material of the terrestrial planet in the Habitable Zone may be transferred from the farther places by this mechanism. Accretion may also happen a few times between two giant planets only if the outer planet has a moderate mass and the small terrestrial planet could survive at some resonances over time scale of 108 yr.

  2. Predictability of the terrestrial carbon cycle.

    Science.gov (United States)

    Luo, Yiqi; Keenan, Trevor F; Smith, Matthew

    2015-05-01

    Terrestrial ecosystems sequester roughly 30% of anthropogenic carbon emission. However this estimate has not been directly deduced from studies of terrestrial ecosystems themselves, but inferred from atmospheric and oceanic data. This raises a question: to what extent is the terrestrial carbon cycle intrinsically predictable? In this paper, we investigated fundamental properties of the terrestrial carbon cycle, examined its intrinsic predictability, and proposed a suite of future research directions to improve empirical understanding and model predictive ability. Specifically, we isolated endogenous internal processes of the terrestrial carbon cycle from exogenous forcing variables. The internal processes share five fundamental properties (i.e., compartmentalization, carbon input through photosynthesis, partitioning among pools, donor pool-dominant transfers, and the first-order decay) among all types of ecosystems on the Earth. The five properties together result in an emergent constraint on predictability of various carbon cycle components in response to five classes of exogenous forcing. Future observational and experimental research should be focused on those less predictive components while modeling research needs to improve model predictive ability for those highly predictive components. We argue that an understanding of predictability should provide guidance on future observational, experimental and modeling research. © 2014 John Wiley & Sons Ltd.

  3. Phytolith carbon sequestration in global terrestrial biomes.

    Science.gov (United States)

    Song, Zhaoliang; Liu, Hongyan; Strömberg, Caroline A E; Yang, Xiaomin; Zhang, Xiaodong

    2017-12-15

    Terrestrial biogeochemical carbon (C) sequestration is coupled with the biogeochemical silicon (Si) cycle through mechanisms such as phytolith C sequestration, but the size and distribution of the phytolith C sink remain unclear. Here, we estimate phytolith C sequestration in global terrestrial biomes. We used biome data including productivity, phytolith and silica contents, and the phytolith stability factor to preliminarily determine the size and distribution of the phytolith C sink in global terrestrial biomes. Total phytolith C sequestration in global terrestrial biomes is 156.7±91.6TgCO2yr-1. Grassland (40%), cropland (35%), and forest (20%) biomes are the dominant producers of phytolith-based carbon; geographically, the main contributors are Asia (31%), Africa (24%), and South America (17%). Practices such as bamboo afforestation/reforestation and grassland recovery for economic and ecological purposes could theoretically double the above phytolith C sink. The potential terrestrial phytolith C sequestration during 2000-2099 under such practices would be 15.7-40.5PgCO2, equivalent in magnitude to the C sequestration of oceanic diatoms in sediments and through silicate weathering. Phytolith C sequestration contributes vitally to the global C cycle, hence, it is essential to incorporate plant-soil silica cycling in biogeochemical C cycle models. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Terrestrial propagation of long electromagnetic waves

    CERN Document Server

    Galejs, Janis; Fock, V A

    2013-01-01

    Terrestrial Propagation of Long Electromagnetic Waves deals with the propagation of long electromagnetic waves confined principally to the shell between the earth and the ionosphere, known as the terrestrial waveguide. The discussion is limited to steady-state solutions in a waveguide that is uniform in the direction of propagation. Wave propagation is characterized almost exclusively by mode theory. The mathematics are developed only for sources at the ground surface or within the waveguide, including artificial sources as well as lightning discharges. This volume is comprised of nine chapte

  5. Were early pterosaurs inept terrestrial locomotors?

    Directory of Open Access Journals (Sweden)

    Mark P. Witton

    2015-06-01

    Full Text Available Pterodactyloid pterosaurs are widely interpreted as terrestrially competent, erect-limbed quadrupeds, but the terrestrial capabilities of non-pterodactyloids are largely thought to have been poor. This is commonly justified by the absence of a non-pterodactyloid footprint record, suggestions that the expansive uropatagia common to early pterosaurs would restrict hindlimb motion in walking or running, and the presence of sprawling forelimbs in some species. Here, these arguments are re-visited and mostly found problematic. Restriction of limb mobility is not a problem faced by extant animals with extensive fight membranes, including species which routinely utilise terrestrial locomotion. The absence of non-pterodactyloid footprints is not necessarily tied to functional or biomechanical constraints. As with other fully terrestrial clades with poor ichnological records, biases in behaviour, preservation, sampling and interpretation likely contribute to the deficit of early pterosaur ichnites. Suggestions that non-pterodactyloids have slender, mechanically weak limbs are demonstrably countered by the proportionally long and robust limbs of many Triassic and Jurassic species. Novel assessments of pterosaur forelimb anatomies conflict with notions that all non-pterodactyloids were obligated to sprawling forelimb postures. Sprawling forelimbs seem appropriate for species with ventrally-restricted glenoid articulations (seemingly occurring in rhamphorhynchines and campylognathoidids. However, some early pterosaurs, such as Dimorphodon macronyx and wukongopterids, have glenoid arthrologies which are not ventrally restricted, and their distal humeri resemble those of pterodactyloids. It seems fully erect forelimb stances were possible in these pterosaurs, and may be probable given proposed correlation between pterodactyloid-like distal humeral morphology and forces incurred through erect forelimb postures. Further indications of terrestrial habits include

  6. Were early pterosaurs inept terrestrial locomotors?

    Science.gov (United States)

    Witton, Mark P

    2015-01-01

    Pterodactyloid pterosaurs are widely interpreted as terrestrially competent, erect-limbed quadrupeds, but the terrestrial capabilities of non-pterodactyloids are largely thought to have been poor. This is commonly justified by the absence of a non-pterodactyloid footprint record, suggestions that the expansive uropatagia common to early pterosaurs would restrict hindlimb motion in walking or running, and the presence of sprawling forelimbs in some species. Here, these arguments are re-visited and mostly found problematic. Restriction of limb mobility is not a problem faced by extant animals with extensive fight membranes, including species which routinely utilise terrestrial locomotion. The absence of non-pterodactyloid footprints is not necessarily tied to functional or biomechanical constraints. As with other fully terrestrial clades with poor ichnological records, biases in behaviour, preservation, sampling and interpretation likely contribute to the deficit of early pterosaur ichnites. Suggestions that non-pterodactyloids have slender, mechanically weak limbs are demonstrably countered by the proportionally long and robust limbs of many Triassic and Jurassic species. Novel assessments of pterosaur forelimb anatomies conflict with notions that all non-pterodactyloids were obligated to sprawling forelimb postures. Sprawling forelimbs seem appropriate for species with ventrally-restricted glenoid articulations (seemingly occurring in rhamphorhynchines and campylognathoidids). However, some early pterosaurs, such as Dimorphodon macronyx and wukongopterids, have glenoid arthrologies which are not ventrally restricted, and their distal humeri resemble those of pterodactyloids. It seems fully erect forelimb stances were possible in these pterosaurs, and may be probable given proposed correlation between pterodactyloid-like distal humeral morphology and forces incurred through erect forelimb postures. Further indications of terrestrial habits include antungual

  7. High efficiency, long life terrestrial solar panel

    Science.gov (United States)

    Chao, T.; Khemthong, S.; Ling, R.; Olah, S.

    1977-01-01

    The design of a high efficiency, long life terrestrial module was completed. It utilized 256 rectangular, high efficiency solar cells to achieve high packing density and electrical output. Tooling for the fabrication of solar cells was in house and evaluation of the cell performance was begun. Based on the power output analysis, the goal of a 13% efficiency module was achievable.

  8. Forest inventory with terrestrial LiDAR

    NARCIS (Netherlands)

    Bauwens, Sébastien; Bartholomeus, Harm; Calders, Kim; Lejeune, Philippe

    2016-01-01

    The application of static terrestrial laser scanning (TLS) in forest inventories is becoming more effective. Nevertheless, the occlusion effect is still limiting the processing efficiency to extract forest attributes. The use of a mobile laser scanner (MLS) would reduce this occlusion. In this

  9. Dental anomaly in Tapirus terrestris (L.)

    NARCIS (Netherlands)

    Hooijer, D.A.

    1961-01-01

    A male skull of Tapirus terrestris (L.) originating from Dutch Guiana (Leiden Museum, reg. no. 11632), received from the Rotterdam Zoological Garden through the kind intermediary of Mr. F. J. APPELMAN on July 15, 1952, is remarkable for the abnormal development of its right P1. The full permanent

  10. Strategies for monitoring terrestrial animals and habitats

    Science.gov (United States)

    Richard Holthausen; Raymond L. Czaplewski; Don DeLorenzo; Greg Hayward; Winifred B. Kessler; Pat Manley; Kevin S. McKelvey; Douglas S. Powell; Leonard F. Ruggiero; Michael K. Schwartz; Bea Van Horne; Christina D. Vojta

    2005-01-01

    This General Technical Report (GTR) addresses monitoring strategies for terrestrial animals and habitats. It focuses on monitoring associated with National Forest Management Act planning and is intended to apply primarily to monitoring efforts that are broader than individual National Forests. Primary topics covered in the GTR are monitoring requirements; ongoing...

  11. Ethnopharmacological Studies of Tribulus Terrestris (Linn). in ...

    African Journals Online (AJOL)

    Synergism and antagonism impact of different plant metabolites present in crude fruit extract of Tribulus terrestris 'the herbal Viagra' have been studied. Variability in plant composition, biomass and metabolites concentration in different modules was significantly contributed by spatial factor. However the edhaphic ...

  12. Pacific Remote Islands MNM: Initial Survey Instructions for Terrestrial Arthropods

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purposes of the terrestrial arthropod surveys are to: develop a species list of native and non-native terrestrial arthropods on land portions of the refuge;...

  13. 77 FR 18271 - Terrestrial Environmental Studies for Nuclear Power Stations

    Science.gov (United States)

    2012-03-27

    ... COMMISSION Terrestrial Environmental Studies for Nuclear Power Stations AGENCY: Nuclear Regulatory Commission... revision to Regulatory Guide (RG) 4.11, ``Terrestrial Environmental Studies for Nuclear Power Stations... environmental studies and analyses supporting licensing decisions for nuclear power reactors. ADDRESSES: Please...

  14. Louisiana ESI: T_MAMMAL (Terrestrial Mammal Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for terrestrial mammals in Louisiana. Vector polygons in this data set represent terrestrial mammal...

  15. Terrestrial forest management plan for Palmyra Atoll

    Science.gov (United States)

    Hathaway, Stacie A.; McEachern, Kathryn; Fisher, Robert N.

    2011-01-01

    This 'Terrestrial Forest Management Plan for Palmyra Atoll' was developed by the U.S. Geological Survey (USGS) for The Nature Conservancy (TNC) Palmyra Program to refine and expand goals and objectives developed through the Conservation Action Plan process. It is one in a series of adaptive management plans designed to achieve TNC's mission toward the protection and enhancement of native wildlife and habitat. The 'Terrestrial Forest Management Plan for Palmyra Atoll' focuses on ecosystem integrity and specifically identifies and addresses issues related to assessing the status and distribution of resources, as well as the pressures acting upon them, most specifically nonnative and potentially invasive species. The plan, which presents strategies for increasing ecosystem integrity, provides a framework to implement and track the progress of conservation and restoration goals related to terrestrial resources on Palmyra Atoll. The report in its present form is intended to be an overview of what is known about historical and current forest resources; it is not an exhaustive review of all available literature relevant to forest management but an attempt to assemble as much information specific to Palmyra Atoll as possible. Palmyra Atoll is one of the Northern Line Islands in the Pacific Ocean southwest of the Hawai`ian Islands. It consists of many heavily vegetated islets arranged in a horseshoe pattern around four lagoons and surrounded by a coral reef. The terrestrial ecosystem consists of three primary native vegetation types: Pisonia grandis forest, coastal strand forest, and grassland. Among these vegetation types, the health and extent of Pisonia grandis forest is of particular concern. Overall, the three vegetation types support 25 native plant species (two of which may be extirpated), 14 species of sea birds, six shore birds, at least one native reptile, at least seven native insects, and six native land crabs. Green and hawksbill turtles forage at Palmyra Atoll

  16. Space and Terrestrial Photovoltaics: Synergy and Diversity

    Science.gov (United States)

    Bailey, Sheila; Raffaelle, Ryne; Emery, Keith

    2002-01-01

    A historical view of the research and development in photovoltaics from the perspective of both the terrestrial and the space communities is presented from the early days through the '70s and '80s and the '90s and beyond. The synergy of both communities in the beginning and once again in the present and hopefully future are highlighted, with examples of the important features in each program. The space community which was impressed by the light-weight and reliability of photovoltaics drove much of the early development. Even up to today, nearly every satellites and other scientific space probe that has been launched has included some solar power. However, since the cost of these power systems were only a small fraction of the satellite and launch cost, the use of much of this technology for the terrestrial marketplace was not feasible. It was clear that the focus of the terrestrial community would be best served by reducing costs. This would include addressing a variety of manufacturing issues and raising the rate of production. Success in these programs and a resulting globalization of effort resulted in major strides in the reduction of PV module costs and increased production. Although, the space community derived benefit from some of these advancements, its focus was on pushing the envelope with regard to cell efficiency. The gap between theoretical efficiencies and experimental efficiencies for silicon, gallium arsenide and indium phosphide became almost non-existent. Recent work by both communities have focused on the development thin film cells of amorphous silicon, CuInSe2 and CdTe. These cells hold the promise of lower costs for the terrestrial community as well as possible flexible substrates, better radiation resistance, and higher specific power for the space community. It is predicted that future trends in both communities will be directed toward advances through the application of nanotechnology. A picture is emerging in which the space and

  17. MODIS-derived terrestrial primary production [chapter 28

    Science.gov (United States)

    Maosheng Zhao; Steven Running; Faith Ann Heinsch; Ramakrishna Nemani

    2011-01-01

    Temporal and spatial changes in terrestrial biological productivity have a large impact on humankind because terrestrial ecosystems not only create environments suitable for human habitation, but also provide materials essential for survival, such as food, fiber and fuel. A recent study estimated that consumption of terrestrial net primary production (NPP; a list of...

  18. Study of hydrocarbon miscible solvent slug injection process for improved recovery of heavy oil from Schrader Bluff Pool, Milne Point Unit, Alaska. Annual report, December 1, 1992--December 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, G.D.

    1994-01-01

    The shallow Cretaceous sands of the Schrader Bluff Reservoir occur between depths of 4,000 and 4,800 feet below surface and are estimated to contain up to 1.5 billion barrels of oil in place. The field is currently under production by primary depletion. Initial production indicated that primary recovery will fall short of earlier estimates and waterflooding will have to be employed much earlier than expected. A large portion of the oil-in-place thus would still be left behind in this reservoir after primary and secondary recovery methods have been applied. Enhanced oil recovery (EOR) techniques will be needed to recover the additional portion of remaining oil in this huge reservoir and to add significant additional reserves. Slim tube displacement studies, PVT data and asphaltene precipitation studies are needed for Schrader Bluff heavy oil to define possible hydrocarbon solvent suitable for miscible solvent slug displacement process. Such studies are essential because the API gravity of the crude in Schrader Bluff reservoir varies significantly from well to well. Coreflood experiments are also needed to determine effect of solvent slug size, WAG ratio and solvent composition on the oil recovery and solvent breakthrough. A compositional reservoir simulation study will be conducted later to evaluate the complete performance of the hydrocarbon solvent slug process and to assess the feasibility of this process for improving recovery of heavy oil from Schrader Bluff reservoir. This report contains the following: reservoir description; slim tube displacement studies; and coreflood experiments.

  19. A Regulatory Network Involving β-Catenin, e-Cadherin, PI3k/Akt, and Slug Balances Self-Renewal and Differentiation of Human Pluripotent Stem Cells In Response to Wnt Signaling.

    Science.gov (United States)

    Huang, Tyng-Shyan; Li, Li; Moalim-Nour, Lilian; Jia, Deyong; Bai, Jian; Yao, Zemin; Bennett, Steffany A L; Figeys, Daniel; Wang, Lisheng

    2015-05-01

    The mechanisms underlying disparate roles of the canonical Wnt signaling pathway in maintaining self-renewal or inducing differentiation and lineage specification in embryonic stem cells (ESCs) are not clear. In this study, we provide the first demonstration that self-renewal versus differentiation of human ESCs (hESCs) in response to Wnt signaling is predominantly determined by a two-layer regulatory circuit involving β-catenin, E-cadherin, PI3K/Akt, and Slug in a time-dependent manner. Short-term upregulation of β-catenin does not lead to the activation of T-cell factor (TCF)-eGFP Wnt reporter in hESCs. Instead, it enhances E-cadherin expression on the cell membrane, thereby enhancing hESC self-renewal through E-cadherin-associated PI3K/Akt signaling. Conversely, long-term Wnt activation or loss of E-cadherin intracellular β-catenin binding domain induces TCF-eGFP activity and promotes hESC differentiation through β-catenin-induced upregulation of Slug. Enhanced expression of Slug leads to a further reduction of E-cadherin that serves as a β-catenin "sink" sequestering free cytoplasmic β-catenin. The formation of such a framework reinforces hESCs to switch from a state of temporal self-renewal associated with short-term Wnt/β-catenin activation to definitive differentiation. Stem Cells 2015;33:1419-1433. © 2015 AlphaMed Press.

  20. Terrestrial freshwater lenses: Unexplored subterranean oases

    Science.gov (United States)

    Laattoe, Tariq; Werner, Adrian D.; Woods, Juliette A.; Cartwright, Ian

    2017-10-01

    Freshwater lenses are lenticular bodies of fresh (TDS lenses in coastal aquifers, the formation, location and persistence of freshwater lenses in terrestrial settings are poorly understood. This is despite inland aquifers commonly containing saline groundwater, particularly in arid and semi-arid climates, and the local occurrences of freshwater being critical for ecosystems and human endeavour. We identify and classify known terrestrial freshwater lenses (TFLs) using four formation categories, namely topography, geology, groundwater-surface water interaction and recharge mechanisms. The resulting typology highlights the importance of buoyancy in the formation of TFLs in otherwise unlikely situations, implying that TFLs may be more prevalent than previously thought. TFLs represent some of the most vulnerable and precious freshwater resources on Earth that require considerably more research into mechanisms of formation and threats to their existence.

  1. Effect factors for terrestrial acidification in Brazil

    DEFF Research Database (Denmark)

    Crespo Mendes, Natalia; Laurent, Alexis; Hauschild, Michael Zwicky

    conditions, which is an essential approach considering countries like Brazil, with high biodiversity. Previous studies have assessed the impacts of terrestrial acidification from the estimations of the potential losses of vascular plants species richness as a result of exposure to acidifying substances...... for 13 biomes, with 2409 species addressed for whole world. In this context this work aims to provide spatially-differentiated effect factors (EF) for terrestrial acidification in Brazil and support the development of spatially-differentiated characterization factors for Brazil. In order to maintain...... in Brazil, represented by 33167 species, indicating that this is a comprehensive study. Maps of soil pH in Brazil were extracted at 1-km resolution and pH values were extracted for the depth range of 0-30cm. For each ecoregion, species richness was plotted against soil pH and the exposure-response curves...

  2. Spiral arms, comets and terrestrial catastrophism

    Energy Technology Data Exchange (ETDEWEB)

    Clube, S.V.M.; Napier, W.M. (Royal Observatory, Edinburgh (UK))

    1982-03-01

    A review is presented of an hypothesis of terrestrial catastrophism in which comets grow in molecular clouds and are captured by the Sun as it passes through the spiral arms of the Galaxy. Assuming that comets are a major supplier of the Earth-crossing (Appollo) asteroid population, the latter fluctuates correspondingly and leads to episodes of terrestrial bombardment. Changes in the rotational momentum of core and mantle, generated by impacts, lead to episodes of magnetic field reversal and tectonic activity, while surface phenomena lead to ice-ages and mass extinctions. An episodic geophysical history with an interstellar connection is thus implied. If comets in spiral arms are necessary intermediaries in the process of star formation, the theory also has implications relating to early solar system history and galactic chemistry. These aspects are briefly discussed with special reference to the nature of spiral arms.

  3. Innovative Technologies for Terrestrial Remote Sensing

    Directory of Open Access Journals (Sweden)

    Paul Aplin

    2015-04-01

    Full Text Available Characterizing and monitoring terrestrial, or land, surface features, such as forests, deserts, and cities, are fundamental and continuing goals of Earth Observation (EO. EO imagery and related technologies are essential for increasing our scientific understanding of environmental processes, such as carbon capture and albedo change, and to manage and safeguard environmental resources, such as tropical forests, particularly over large areas or the entire globe. This measurement or observation of some property of the land surface is central to a wide range of scientific investigations and industrial operations, involving individuals and organizations from many different backgrounds and disciplines. However, the process of observing the land provides a unifying theme for these investigations, and in practice there is much consistency in the instruments used for observation and the techniques used to map and model the environmental phenomena of interest. There is therefore great potential benefit in exchanging technological knowledge and experience among the many and diverse members of the terrestrial EO community. [...

  4. The overlooked terrestrial impacts of mountaintop mining

    Science.gov (United States)

    Wickham, James; Wood, Petra Bohall; Nicholson, Matthew C.; Jenkins, William; Druckenbrod, Daniel; Suter, Glenn W.; Strager, Michael P.; Mazzarella, Christine; Galloway, Walter; Amos, John

    2013-01-01

    Ecological research on mountaintop mining has been focused on aquatic impacts because the overburden (i.e., the mountaintop) is disposed of in nearby valleys, which leads to a wide range of water-quality impacts on streams. There are also numerous impacts on the terrestrial environment from mountaintop mining that have been largely overlooked, even though they are no less wide ranging, severe, and multifaceted. We review the impacts of mountaintop mining on the terrestrial environment by exploring six broad themes: (1) the loss of topographic complexity, (2) forest loss and fragmentation, (3) forest succession and soil loss, (4) forest loss and carbon sequestration, (5) biodiversity, and (6) human health and well-being.

  5. Terrestrial imaging of military test centers

    Science.gov (United States)

    Fleming, Steven D.

    2010-04-01

    Military test centers require detailed site descriptions. Test agencies demand significant written and visual information of test sites in order to facilitate successful test preparation and execution. New terrestrial imaging techniques (360 degree FOV collection) have recently become feasible to collect in the field. Combined with GIS and mapping applications, image and video data is now provided to test agencies for their use. Test sites for this study include locations in Alaska and Panama with planned image data collection in Arizona and Maryland.

  6. Terrestrial analogues for lunar impact melt flows

    Science.gov (United States)

    Neish, C. D.; Hamilton, C. W.; Hughes, S. S.; Nawotniak, S. Kobs; Garry, W. B.; Skok, J. R.; Elphic, R. C.; Schaefer, E.; Carter, L. M.; Bandfield, J. L.; Osinski, G. R.; Lim, D.; Heldmann, J. L.

    2017-01-01

    Lunar impact melt deposits have unique physical properties. They have among the highest observed radar returns at S-Band (12.6 cm wavelength), implying that they are rough at the decimeter scale. However, they are also observed in high-resolution optical imagery to be quite smooth at the meter scale. These characteristics distinguish them from well-studied terrestrial analogues, such as Hawaiian pāhoehoe and ´a´ā lava flows. The morphology of impact melt deposits can be related to their emplacement conditions, so understanding the origin of these unique surface properties will help to inform us as to the circumstances under which they were formed. In this work, we seek to find a terrestrial analogue for well-preserved lunar impact melt flows by examining fresh lava flows on Earth. We compare the radar return and high-resolution topographic variations of impact melt flows to terrestrial lava flows with a range of surface textures. The lava flows examined in this work range from smooth Hawaiian pāhoehoe to transitional basaltic flows at Craters of the Moon (COTM) National Monument and Preserve in Idaho to rubbly and spiny pāhoehoe-like flows at the recent eruption at Holuhraun in Iceland. The physical properties of lunar impact melt flows appear to differ from those of all the terrestrial lava flows studied in this work. This may be due to (a) differences in post-emplacement modification processes or (b) fundamental differences in the surface texture of the melt flows due to the melts' unique emplacement and/or cooling environment. Information about the surface properties of lunar impact melt deposits will be critical for future landed missions that wish to sample these materials.

  7. Tidally driven evolution of differentiated terrestrial exoplanets

    Science.gov (United States)

    Walterova, M.; Behounkova, M.

    2017-09-01

    We present a numerical model of tidally driven orbital evolution based on the solution of continuum mechanics equations for a differentiated spherical body, whose mantle is governed by either the Maxwell or the Andrade viscoelastic rheology. The model enables generally heterogeneous structure of the mantle, making thus possible the analysis of coupling between the internal and the orbital evolution of terrestrial exoplanets or icy moons.

  8. WOODS, THE MOST COMPLEX TERRESTRIAL ECOSISTEM

    OpenAIRE

    BLAJ Robert; SAND Camelia; Gligor CIORTEA

    2012-01-01

    A forest ecosystem is a terrestrial unit of living organisms (plants, animals and microorganisms), all interacting among themselves and with the environment (soil, climate, water and light) in which they live. The environmental "common denominator" of that forest ecological community is a tree, who most faithfully obeys the ecological cycles of energy, water, carbon and nutrients. A forest ecosystem would be considered having boundaries and would include a forest of trees out to the limit of ...

  9. Terrestrial Impack Cratering Chronology : A Preliminary Analysis

    Directory of Open Access Journals (Sweden)

    Hong-Kyu Moon

    2001-12-01

    Full Text Available We have recently compiled a database of the properties of 192 impact craters, which supercedes previous compilations. Using our database, the impact structures found in North America, Europe and Australia have been examined; these cratonic areas have been relatively stable for considerably long geological periods, and thus have been best preserved. It is confirmed that there is a close correlation between the geological epoch boundaries, the epochs of mass extinctions, and the ``timing'' of impacts. In addition, the terrestrial cumulative flux of objects >20km is found to be 1.77×10-15km-2yr-1, over the last 120 Myr, which is much smaller than the published values in McEwen et al. (1997 and Shoemaker (1998 (5.6±2.8×10-15km-2yr-1. For terrestrial impact structures with D>50 km, the apparent cumulative flux over the last 2450 Myr is ~50 times smaller than the corresponding value for the Moon. If we assume that the Earth and the Moon suffered the same level of bombardment over this time, this would mean that the actual flux of impacting bodies, capable of making craters with D>50 km, was ~ 50 times larger than the apparent flux estimated from the currently known terrestrial records.

  10. Obliquity and Eccentricity Constraints for Terrestrial Exoplanets

    Science.gov (United States)

    Kane, Stephen R.; Torres, Stephanie M.

    2017-11-01

    Exoplanet discoveries over recent years have shown that terrestrial planets are exceptionally common. Many of these planets are in compact systems that result in complex orbital dynamics. A key step toward determining the surface conditions of these planets is understanding the latitudinally dependent flux incident at the top of the atmosphere as a function of orbital phase. The two main properties of a planet that influence the time-dependent nature of the flux are the obliquity and orbital eccentricity of the planet. We derive the criterion for which the flux variation due to obliquity is equivalent to the flux variation due to orbital eccentricity. This equivalence is computed for both the maximum and average flux scenarios, the latter of which includes the effects of the diurnal cycle. We apply these calculations to four known multi-planet systems (GJ 163, K2-3, Kepler-186, and Proxima Centauri), where we constrain the eccentricity of terrestrial planets using orbital dynamics considerations and model the effect of obliquity on incident flux. We discuss the implications of these simulations on climate models for terrestrial planets and outline detectable signatures of planetary obliquity.

  11. Integrative species delimitation in photosynthetic sea slugs reveals twenty candidate species in three nominal taxa studied for drug discovery, plastid symbiosis or biological control.

    Science.gov (United States)

    Krug, Patrick J; Vendetti, Jann E; Rodriguez, Albert K; Retana, Jennifer N; Hirano, Yayoi M; Trowbridge, Cynthia D

    2013-12-01

    DNA barcoding can highlight taxa in which conventional taxonomy underestimates species richness, identifying mitochondrial lineages that may correspond to unrecognized species. However, key assumptions of barcoding remain untested for many groups of soft-bodied marine invertebrates with poorly resolved taxonomy. Here, we applied an integrative approach for species delimitation to herbivorous sea slugs in clade Sacoglossa, in which unrecognized diversity may complicate studies of drug discovery, plastid endosymbiosis, and biological control. Using the mitochondrial barcoding COI gene and the nuclear histone 3 gene, we tested the hypothesis that three widely distributed "species" each comprised a complex of independently evolving lineages. Morphological and reproductive characters were then used to evaluate whether each lineage was distinguishable as a candidate species. The "circumtropical" Elysia ornata comprised a Caribbean species and four Indo-Pacific candidate species that are potential sources of kahalalides, anti-cancer compounds. The "monotypic" and highly photosynthetic Plakobranchus ocellatus, used for over 60 years to study chloroplast symbiosis, comprised 10 candidate species. Finally, six candidate species were distinguished in the Elysia tomentosa complex, including potential biological control agents for invasive green algae (Caulerpa spp.). We show that a candidate species approach developed for vertebrates effectively categorizes cryptic diversity in marine invertebrates, and that integrating threshold COI distances with non-molecular character data can delimit species even when common assumptions of DNA barcoding are violated. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Integrative species delimitation in photosynthetic sea slugs reveals twenty candidate species in three nominal taxa studied for drug discovery, plastid symbiosis or biological control

    Science.gov (United States)

    Krug, Patrick J.; Vendetti, Jann E.; Rodriguez, Albert K.; Retana, Jennifer N.; Hirano, Yayoi M.; Trowbridge, Cynthia D.

    2013-01-01

    DNA barcoding can highlight taxa in which conventional taxonomy underestimates species richness, identifying mitochondrial lineages that may correspond to unrecognized species. However, key assumptions of barcoding remain untested for many groups of soft-bodied marine invertebrates with poorly resolved taxonomy. Here, we applied an integrative approach for species delimitation to herbivorous sea slugs in clade Sacoglossa, in which unrecognized diversity may complicate studies of drug discovery, plastid endosymbiosis, and biological control. Using the mitochondrial barcoding COI gene and the nuclear histone 3 gene, we tested the hypothesis that three widely distributed “species” each comprised a complex of independently evolving lineages. Morphological and reproductive characters were then used to evaluate whether each lineage was distinguishable as a candidate species. The “circumtropical” Elysia ornata comprised a Caribbean species and four Indo-Pacific candidate species that are potential sources of kahalalides, anti-cancer compounds. The “monotypic” and highly photosynthetic Plakobranchus ocellatus, used for over 60 years to study chloroplast symbiosis, comprised 10 candidate species. Finally, six candidate species were distinguished in the Elysia tomentosa complex, including potential biological control agents for invasive green algae (Caulerpa spp.). We show that a candidate species approach developed for vertebrates effectively categorizes cryptic diversity in marine invertebrates, and that integrating threshold COI distances with non-molecular character data can delimit species even when common assumptions of DNA barcoding are violated. PMID:23876292

  13. Microplastics in the Terrestrial Ecosystem: Implications for Lumbricus terrestris (Oligochaeta, Lumbricidae).

    Science.gov (United States)

    Huerta Lwanga, Esperanza; Gertsen, Hennie; Gooren, Harm; Peters, Piet; Salánki, Tamás; van der Ploeg, Martine; Besseling, Ellen; Koelmans, Albert A; Geissen, Violette

    2016-03-01

    Plastic debris is widespread in the environment, but information on the effects of microplastics on terrestrial fauna is completely lacking. Here, we studied the survival and fitness of the earthworm Lumbricus terrestris (Oligochaeta, Lumbricidae) exposed to microplastics (Polyethylene, microplastics in the litter than at 7% w/w and in the control (0%). Growth rate was significantly reduced at 28, 45, and 60% w/w microplastics, compared to the 7% and control treatments. Due to the digestion of ingested organic matter, microplastic was concentrated in cast, especially at the lowest dose (i.e., 7% in litter) because that dose had the highest proportion of digestible organic matter. Whereas 50 percent of the microplastics had a size of microplastics in the casts was microplastic in terrestrial ecosystems.

  14. Teppeki, selective insecticide about Bombus terrestris.

    Science.gov (United States)

    Fanigliulo, Angela; Filì, Vittorio; Pacella, Rosa; Comes, Soccorsa; Crescenzi, Aniello

    2009-01-01

    At a time when a highly controversial debate about the causes of the widespread deaths of bees is taking place all over Europe, which accused the agriculture and its practices with particular reference to the harmful effects of some insecticides, it seems important to point out as another insecticide, the Teppeki, can be selective about bumble and have a good compatibility with the activity of the apiaries. This insecticide has the active ingredient flonicamid (500 g/kg) belonging to a new chemical class, called pyridinecarboxamides: the product works systemic and is known as having a long lasting efficacy against all important aphid species. Bioagritest test facility of Pignola (PZ, Italy) has conducted in two successive production cycles an experimental trial on a tomato hydroponic cultivation within the Agricola Bonsai farm in Sibari (CS, Italy), whose objective was to measure the selectivity of flonicamid on Bombus terrestris, insects playing an important role in the pollination of certain species grown in greenhouse such as Tomato, Eggplant, Pepper and Cucumber. On the pollinated flower B. terrestris leaves some trace of its visit, a typical dark trademark: on the detection of the marking of flowers was based the testing program conducted by Bioagritest. Two thesis were compared: A, standard) treatment with a foliar insecticide, the neonicotinoide acetamiprid, normally used for control of aphids and whiteflies (unlike other neonicotinoides--imidacloprid and thiametoxam--quite selective about B. terrestris) and B, Teppeki) foliar treatment with Teppeki, to the maximum dose indicated on the label. The experimental design included the use of randomized blocks with 4 repetitions (4 plots/thesis with 100 plants each). In every thesis six B. terrestris hives were placed 2 days before treatment: the respective holes remained closed during the treatment and the 12 following hours. In order to verify the pollination, by the detection of the flower marking, 2 flowers

  15. Stochasticity and predictability in terrestrial planet formation

    Science.gov (United States)

    Hoffmann, Volker; Grimm, Simon L.; Moore, Ben; Stadel, Joachim

    2017-02-01

    Terrestrial planets are thought to be the result of a vast number of gravitational interactions and collisions between smaller bodies. We use numerical simulations to show that practically identical initial conditions result in a wide array of final planetary configurations. This is a result of the chaotic evolution of trajectories which are highly sensitive to minuscule displacements. We determine that differences between systems evolved from virtually identical initial conditions can be larger than the differences between systems evolved from very different initial conditions. This implies that individual simulations lack predictive power. For example, there is not a reproducible mapping between the initial and final surface density profiles. However, some key global properties can still be extracted if the statistical spread across many simulations is considered. Based on these spreads, we explore the collisional growth and orbital properties of terrestrial planets, which assemble from different initial conditions (we vary the initial planetesimal distribution, planetesimal masses, and giant planet orbits.). Confirming past work, we find that the resulting planetary systems are sculpted by sweeping secular resonances. Configurations with giant planets on eccentric orbits produce fewer and more massive terrestrial planets on tighter orbits than those with giants on circular orbits. This is further enhanced if the initial mass distribution is biased to the inner regions. In all cases, the outer edge of the system is set by the final location of the ν6 resonance and we find that the mass distribution peaks at the ν5 resonance. Using existing observations, we find that extrasolar systems follow similar trends. Although differences between our numerical modelling and exoplanetary systems remain, we suggest that CoRoT-7, HD 20003 and HD 20781 may host undetected giant planets.

  16. Evolution of ore deposits on terrestrial planets

    Science.gov (United States)

    Burns, R. G.

    1991-01-01

    Ore deposits on terrestrial planets materialized after core formation, mantle evolution, crustal development, interactions of surface rocks with the hydrosphere and atmosphere, and, where life exists on a planet, the involvement of biological activity. Core formation removed most of the siderophilic and chalcophilic elements, leaving mantles depleted in many of the strategic and noble metals relative to their chondritic abundances. Basaltic magma derived from partial melting of the mantle transported to the surface several metals contained in immiscible silicate and sulfide melts. Magmatic ore deposits were formed during cooling, fractional crystallization and density stratification from the basaltic melts. Such ore deposits found in earth's Archean rocks were probably generated during early histories of all terrestrial planets and may be the only types of igneous ores on Mars. Where plate tectonic activity was prevalent on a terrestrial planet, temporal evolution of ore deposits took place. Repetitive episodes of subduction modified the chemical compositions of the crust and upper mantles, leading to porphyry copper and molybdenum ores in calc-alkaline igneous rocks and granite-hosted tin and tungsten deposits. Such plate tectonic-induced mineralization in relatively young igneous rocks on earth may also have produced hydrothermal ore deposits on Venus in addition to the massive sulfide and cumulate chromite ores associated with Venusian mafic igneous rock. Sedimentary ore deposits resulting from mechanical and chemical weathering in reducing atmospheres in Archean earth included placer deposits (e.g., uraninite, gold, pyrite ores). Chromite, ilmenite, and other dense unreactive minerals could also be present on channel floors and in valley networks on Mars, while banded iron formations might underlie the Martian northern plains regions. As oxygen evolved in earth's atmosphere, so too did oxide ores. By analogy, gossans above sulfide ores probably occur on Mars

  17. Global analytic treatment of terrestrial photogrammetric networks

    CERN Document Server

    Mayoud, M

    1980-01-01

    In order to solve certain special CERN metrology problems, analytical terrestrial photogrammetry may have some advantages which are first discussed along with their drawbacks and limitations. In this application, it is necessary to carry out a rigorous and global adjustment of the observations and simultaneously process all the perspective ray bundles. The basic principles, the least squares solution and the stochastic analysis of the results are presented. However, for the CERN project, one wonders if the production of digital theodolites is going to reduce the advantages of the photogrammetric method. (12 refs).

  18. Handbook of the Solar-Terrestrial Environment

    CERN Document Server

    Kamide, Y

    2007-01-01

    The Handbook of the Solar-Terrestrial Environment is a unique compendium. Recognized international leaders in their field contribute chapters on basic topics of solar physics, space plasmas and the Earth's magnetosphere, and on applied topics like the aurora, magnetospheric storms, space weather, space climatology and planetary science. This book will be of highest value as a reference for researchers working in the area of planetary and space science. However, it is also written in a style accessible to graduate students majoring in those fields.

  19. Terrestrial exoplanets: diversity, habitability and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Selsis, Franck [CRAL: Centre de Recherche Astrophysique de Lyon (CNRS), Universite de Lyon, Ecole Normale Superieure de Lyon, 46 allee d' Italie, F-69007 Lyon (France); Kaltenegger, Lisa [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Paillet, Jimmy [ESTEC SCI-SA, Keplerlaan 1, PO Box 299, 2200AG Noordwijk (Netherlands)], E-mail: franck.selsis@ens-lyon.fr, E-mail: lkaltene@cfa.harvard.edu, E-mail: jpaillet@rssd.esa.int

    2008-08-15

    After a decade rich in giant exoplanet detections, observation techniques have now reached the sensitivity to gain information on the physical structure and chemical content of some of the detected planets and also to find planets of less than 10 M{sub +}. The detection and characterization of Earth-like planets is approaching rapidly and dedicated space observatories are already in operation (CoRoT) or in the development phase (Kepler, Darwin and TPF-I/C). In this paper, we explore the domain of terrestrial planets, emphasizing habitable worlds. We discuss the possibility of performing a spectral characterization of their properties using the next generation of astronomical instruments.

  20. Halogens in chondritic meteorites and terrestrial accretion

    Science.gov (United States)

    Clay, Patricia L.; Burgess, Ray; Busemann, Henner; Ruzié-Hamilton, Lorraine; Joachim, Bastian; Day, James M. D.; Ballentine, Christopher J.

    2017-11-01

    Volatile element delivery and retention played a fundamental part in Earth’s formation and subsequent chemical differentiation. The heavy halogens—chlorine (Cl), bromine (Br) and iodine (I)—are key tracers of accretionary processes owing to their high volatility and incompatibility, but have low abundances in most geological and planetary materials. However, noble gas proxy isotopes produced during neutron irradiation provide a high-sensitivity tool for the determination of heavy halogen abundances. Using such isotopes, here we show that Cl, Br and I abundances in carbonaceous, enstatite, Rumuruti and primitive ordinary chondrites are about 6 times, 9 times and 15-37 times lower, respectively, than previously reported and usually accepted estimates. This is independent of the oxidation state or petrological type of the chondrites. The ratios Br/Cl and I/Cl in all studied chondrites show a limited range, indistinguishable from bulk silicate Earth estimates. Our results demonstrate that the halogen depletion of bulk silicate Earth relative to primitive meteorites is consistent with the depletion of lithophile elements of similar volatility. These results for carbonaceous chondrites reveal that late accretion, constrained to a maximum of 0.5 ± 0.2 per cent of Earth’s silicate mass, cannot solely account for present-day terrestrial halogen inventories. It is estimated that 80-90 per cent of heavy halogens are concentrated in Earth’s surface reservoirs and have not undergone the extreme early loss observed in atmosphere-forming elements. Therefore, in addition to late-stage terrestrial accretion of halogens and mantle degassing, which has removed less than half of Earth’s dissolved mantle gases, the efficient extraction of halogen-rich fluids from the solid Earth during the earliest stages of terrestrial differentiation is also required to explain the presence of these heavy halogens at the surface. The hydropilic nature of halogens, whereby they track

  1. International Solar Terrestrial Physics (ISTP) program

    Science.gov (United States)

    Sanford, R.; Muhonen, D.; Sizemore, K. O.

    1991-01-01

    The International Solar Terrestrial Physics (ISTP) Program is a large, multi-national program involving three space agencies and up to eight spacecraft. NASA, together with the Institute of Space and Astronomical Science (ISAS) and the European Space Agency (ESA), has agreed in principle to coordinate their efforts in investigating the Sun and the Earth. Each agency is planning to construct and operate different spacecraft as part of this cooperative venture: Geotail provided by ISAS, the Solar Heliospheric Observatory (SOHO) and Cluster (four spacecraft) contributed by ESA, and Wind and Polar by NASA. A general description of the program is presented.

  2. Digital terrestrial television broadcasting technology and system

    CERN Document Server

    2015-01-01

    Now under massive deployment worldwide, digital terrestrial television broadcasting (DTTB) offers one of the most attractive ways to deliver digital TV over the VHF/UHF band. Written by a team of experts for specialists and non-specialists alike, this book serves as a comprehensive guide to DTTB. It covers the fundamentals of channel coding and modulation technologies used in DTTB, as well as receiver technology for synchronization, channel estimation, and equalization. It also covers the recently introduced Chinese DTTB standard, using the SFN network in Hong Kong as an example.

  3. Tectonic evolution of the terrestrial planets.

    Science.gov (United States)

    Head, J W; Solomon, S C

    1981-07-03

    The style and evolution of tectonics on the terrestrial planets differ substantially. The style is related to the thickness of the lithosphere and to whether the lithosphere is divided into distinct, mobile plates that can be recycled into the mantle, as on Earth, or is a single spherical shell, as on the moon, Mars, and Mercury. The evolution of a planetary lithosphere and the development of plate tectonics appear to be influenced by several factors, including planetary size, chemistry, and external and internal heat sources. Vertical tectonic movement due to lithospheric loading or uplift is similar on all of the terrestrial planets and is controlled by the local thickness and rheology of the lithosphere. The surface of Venus, although known only at low resolution, displays features both similar to those on Earth (mountain belts, high plateaus) and similar to those on the smaller planets (possible impact basins). Improved understanding of the tectonic evolution of Venus will permit an evaluation of the relative roles of planetary size and chemistry in determining evolutionary style.

  4. Grazers: biocatalysts of terrestrial silica cycling.

    Science.gov (United States)

    Vandevenne, Floor Ina; Barão, Ana Lúcia; Schoelynck, Jonas; Smis, Adriaan; Ryken, Nick; Van Damme, Stefan; Meire, Patrick; Struyf, Eric

    2013-12-07

    Silica is well known for its role as inducible defence mechanism countering herbivore attack, mainly through precipitation of opaline, biogenic silica (BSi) bodies (phytoliths) in plant epidermal tissues. Even though grazing strongly interacts with other element cycles, its impact on terrestrial silica cycling has never been thoroughly considered. Here, BSi content of ingested grass, hay and faeces of large herbivores was quantified by performing multiple chemical extraction procedures for BSi, allowing the assessment of chemical reactivity. Dissolution experiments with grass and faeces were carried out to measure direct availability of BSi for dissolution. Average BSi and readily soluble silica numbers were higher in faeces as compared with grass or hay, and differences between herbivores could be related to distinct digestive strategies. Reactivity and dissolvability of BSi increases after digestion, mainly due to degradation of organic matrices, resulting in higher silica turnover rates and mobilization potential from terrestrial to aquatic ecosystems in non-grazed versus grazed pasture systems (2 versus 20 kg Si ha(-1) y(-1)). Our results suggest a crucial yet currently unexplored role of herbivores in determining silica export from land to ocean, where its availability is linked to eutrophication events and carbon sequestration through C-Si diatom interactions.

  5. Species Selection Favors Dispersive Life Histories in Sea Slugs, but Higher Per-Offspring Investment Drives Shifts to Short-Lived Larvae.

    Science.gov (United States)

    Krug, Patrick J; Vendetti, Jann E; Ellingson, Ryan A; Trowbridge, Cynthia D; Hirano, Yayoi M; Trathen, Danielle Y; Rodriguez, Albert K; Swennen, Cornelis; Wilson, Nerida G; Valdés, Ángel A

    2015-11-01

    For 40 years, paleontological studies of marine gastropods have suggested that species selection favors lineages with short-lived (lecithotrophic) larvae, which are less dispersive than long-lived (planktotrophic) larvae. Although lecithotrophs appeared to speciate more often and accumulate over time in some groups, lecithotrophy also increased extinction rates, and tests for state-dependent diversification were never performed. Molecular phylogenies of diverse groups instead suggested lecithotrophs accumulate without diversifying due to frequent, unidirectional character change. Although lecithotrophy has repeatedly originated in most phyla, no adult trait has been correlated with shifts in larval type. Thus, both the evolutionary origins of lecithotrophy and its consequences for patterns of species richness remain poorly understood. Here, we test hypothesized links between development mode and evolutionary rates using likelihood-based methods and a phylogeny of 202 species of gastropod molluscs in Sacoglossa, a clade of herbivorous sea slugs. Evolutionary quantitative genetics modeling and stochastic character mapping supported 27 origins of lecithotrophy. Tests for correlated evolution revealed lecithotrophy evolved more often in lineages investing in extra-embryonic yolk, the first adult trait associated with shifts in development mode across a group. However, contrary to predictions from paleontological studies, species selection actually favored planktotrophy; most extant lecithotrophs originated through recent character change, and did not subsequently diversify. Increased offspring provisioning in planktotrophs thus favored shifts to short-lived larvae, which led to short-lived lineages over macroevolutionary time scales. These findings challenge long-standing assumptions about the effects of alternative life histories in the sea. Species selection can explain the long-term persistence of planktotrophy, the ancestral state in most clades, despite frequent

  6. The Slugs of Britain and Ireland: Undetected and Undescribed Species Increase a Well-Studied, Economically Important Fauna by More Than 20%

    Science.gov (United States)

    Rowson, Ben; Anderson, Roy; Turner, James A.; Symondson, William O. C.

    2014-01-01

    The slugs of Britain and Ireland form a well-studied fauna of economic importance. They include many widespread European species that are introduced elsewhere (at least half of the 36 currently recorded British species are established in North America, for example). To test the contention that the British and Irish fauna consists of 36 species, and to verify the identity of each, a species delimitation study was conducted based on a geographically wide survey. Comparisons between mitochondrial DNA (COI, 16S), nuclear DNA (ITS-1) and morphology were investigated with reference to interspecific hybridisation. Species delimitation of the fauna produced a primary species hypothesis of 47 putative species. This was refined to a secondary species hypothesis of 44 species by integration with morphological and other data. Thirty six of these correspond to the known fauna (two species in Arion subgenus Carinarion were scarcely distinct and Arion (Mesarion) subfuscus consisted of two near-cryptic species). However, by the same criteria a further eight previously undetected species (22% of the fauna) are established in Britain and/or Ireland. Although overlooked, none are strictly morphologically cryptic, and some appear previously undescribed. Most of the additional species are probably accidentally introduced, and several are already widespread in Britain and Ireland (and thus perhaps elsewhere). At least three may be plant pests. Some evidence was found for interspecific hybridisation among the large Arion species (although not involving A. flagellus) and more unexpectedly in species pairs in Deroceras (Agriolimacidae) and Limacus (Limacidae). In the latter groups, introgression appears to have occurred in one direction only, with recently-invading lineages becoming common at the expense of long-established or native ones. The results show how even a well-studied, macroscopic fauna can be vulnerable to cryptic and undetected invasions and changes. PMID:24740519

  7. The slugs of Britain and Ireland: undetected and undescribed species increase a well-studied, economically important fauna by more than 20%.

    Science.gov (United States)

    Rowson, Ben; Anderson, Roy; Turner, James A; Symondson, William O C

    2014-01-01

    The slugs of Britain and Ireland form a well-studied fauna of economic importance. They include many widespread European species that are introduced elsewhere (at least half of the 36 currently recorded British species are established in North America, for example). To test the contention that the British and Irish fauna consists of 36 species, and to verify the identity of each, a species delimitation study was conducted based on a geographically wide survey. Comparisons between mitochondrial DNA (COI, 16S), nuclear DNA (ITS-1) and morphology were investigated with reference to interspecific hybridisation. Species delimitation of the fauna produced a primary species hypothesis of 47 putative species. This was refined to a secondary species hypothesis of 44 species by integration with morphological and other data. Thirty six of these correspond to the known fauna (two species in Arion subgenus Carinarion were scarcely distinct and Arion (Mesarion) subfuscus consisted of two near-cryptic species). However, by the same criteria a further eight previously undetected species (22% of the fauna) are established in Britain and/or Ireland. Although overlooked, none are strictly morphologically cryptic, and some appear previously undescribed. Most of the additional species are probably accidentally introduced, and several are already widespread in Britain and Ireland (and thus perhaps elsewhere). At least three may be plant pests. Some evidence was found for interspecific hybridisation among the large Arion species (although not involving A. flagellus) and more unexpectedly in species pairs in Deroceras (Agriolimacidae) and Limacus (Limacidae). In the latter groups, introgression appears to have occurred in one direction only, with recently-invading lineages becoming common at the expense of long-established or native ones. The results show how even a well-studied, macroscopic fauna can be vulnerable to cryptic and undetected invasions and changes.

  8. Characterizing the Vertical Distribution of Hydraulic Conductivity Using the Multilevel Slug Test Subject to Skin Effects: Comparison of the Uniform-head and Uniform-flux Wellbore Conditions

    Science.gov (United States)

    wei-Chiang, C.; Chen, C. S.

    2016-12-01

    The multilevel slug test (MLST) is an in-well technique in characterizing the vertical distribution of hydraulic conductivity K(z) in granular or fractured formations. In modeling MLST, the well screen is either simulated as a uniform-flux (UF) or a uniform head (UH) condition. This study investigates the impact of the skin effect, positive or negative, on the UH and UF models. The positive skin effect, as associated with a reduced hydraulic conductivity surrounding the well due to drilling mud invasion, is taken into account by making use of a skin factor, Sk.The negative skin effect, as associated with an increased hydraulic conductivity due to overdeveloping of the well, is modeled by using an effective well radius, re, which is greater than or equal to the well radius, rw. The UF and UH models are compared using different values of Sk and re for a variety of the partial penetration ratio of screen length to aquifer thickness, φ, the vertical anisotropy ratio of hydraulic conductivity, κ, and the aspect ratio of rw to the screen length, α. It is found that (1) the two models yield results of negligible difference when the well fully penetrates the aquifer (i.e., φ=1) regardless of the values of α,κ, Sk or re, (2) the two models yield essentially the same results for negative skin for all α and κ, (3) the difference between the two models decreases as Sk gets larger, regardless of the values of α, φ, or κ, yet it becomes negligible for Sk is greater than unity, and (4) when the skin effect is absent, the maximum difference between the two models is within 3-5%. As a result, it is suggested the UF model be used since it is mathematically easier to solve than the UH model, with or without skin effects.

  9. Terrestrial quarantine considerations for unmanned sample return missions

    Science.gov (United States)

    Hoffman, A. R.; Stavro, W.; Miller, L. W.; Taylor, D. M.

    1973-01-01

    For the purpose of understanding some of the possible implications of a terrestrial quarantine constraint on a mission and for developing a basic approach which can be used to demonstrate compliance beyond that developed for Apollo, a terrestrial quarantine study was performed. It is shown that some of the basic tools developed and used by the planetary quarantine community have applicability to terrestrial quarantine analysis. By using these tools, it is concluded that: (1) the method of biasing the earth aiming point when returning from the planet is necessary but, by itself, may not satisfy terrestrial quarantine constraints; and (2) spacecraft and container design significantly influence contamination transfer.

  10. Workshop on Oxygen in the Terrestrial Planets

    Science.gov (United States)

    2004-01-01

    This volume contains abstracts that have been accepted for presentation at the Workshop on Oxygen in the Terrestrial Planets, July 20-23,2004, Santa Fe, New Mexico. The contents include: 1) Experimental Constraints on Oxygen and Other Light Element Partitioning During Planetary Core Formation; 2) In Situ Determination of Fe(3+)/SigmaFe of Spinels by Electron Microprobe: An Evaluation of the Flank Method; 3) The Effect of Oxygen Fugacity on Large-Strain Deformation and Recrystallization of Olivine; 4) Plagioclase-Liquid Trace Element Oxygen Barometry and Oxygen Behaviour in Closed and Open System Magmatic Processes; 5) Core Formation in the Earth: Constraints from Ni and Co; 6) Oxygen Isotopic Compositions of the Terrestrial Planets; 7) The Effect of Oxygen Fugacity on Electrical Conduction of Olivine and Implications for Earth s Mantle; 8) Redox Chemical Diffusion in Silicate Melts: The Impact of the Semiconductor Condition; 9) Ultra-High Temperature Effects in Earth s Magma Ocean: Pt and W Partitioning; 10) Terrestrial Oxygen and Hydrogen Isotope Variations: Primordial Values, Systematics, Subsolidus Effects, Planetary Comparisons, and the Role of Water; 11) Redox State of the Moon s Interior; 12) How did the Terrestrial Planets Acquire Their Water?; 13) Molecular Oxygen Mixing Ratio and Its Seasonal Variability in the Martian Atmosphere; 14) Exchange Between the Atmosphere and the Regolith of Mars: Discussion of Oxygen and Sulfur Isotope Evidence; 15) Oxygen and Hydrogen Isotope Systematics of Atmospheric Water Vapor and Meteoric Waters: Evidence from North Texas; 16) Implications of Isotopic and Redox Heterogeneities in Silicate Reservoirs on Mars; 17) Oxygen Isotopic Variation of the Terrestrial Planets; 18) Redox Exchanges in Hydrous Magma; 19) Hydrothermal Systems on Terrestrial Planets: Lessons from Earth; 20) Oxygen in Martian Meteorites: A Review of Results from Mineral Equilibria Oxybarometers; 21) Non-Linear Fractionation of Oxygen Isotopes Implanted in

  11. Prediction of slug-to-annular flow pattern transition (STA) for reducing the risk of gas-lift instabilities and effective gas/liquid transport from low-pressure reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Toma, P.R.; Vargas, E.; Kuru, E.

    2007-08-15

    Flow-pattern instabilities have frequently been observed in both conventional gas-lifting and unloading operations of water and oil in low-pressure gas and coalbed reservoirs. This paper identifies the slug-to-annular flow-pattern transition (STA) during upward gas/liquid transportation as a potential cause of flow instability in these operations. It is recommended that the slug-flow pattern be used mainly to minimize the pressure drop and gas compression work associated with gas-lifting large volumes of oil and water. Conversely, the annular flow pattern should be used during the unloading operation to produce gas with relatively small amounts of water and condensate. New and efficient artificial lifting strategies are required to transport the liquid out of the depleted gas or coalbed reservoir level to the surface. This paper presents held data and laboratory measurements supporting the hypothesis that STA significantly contributes to flow instabilities and should therefore be avoided in upward gas/liquid transportation operations. Laboratory high-speed measurements of flow-pressure components under a broad range of gas-injection rates including STA have also been included to illustrate the onset of large STA-related flow-pressure oscillations. The latter body of data provides important insights into gas deliquification mechanisms and identifies potential solutions for improved gas-lifting and unloading procedures. A comparison of laboratory data with existing STA models was performed first. Selected models were then numerically tested in field situations. Effective field strategies for avoiding STA occurrence in marginal and new (offshore) field applications (i.e.. through the use of a slug or annular flow pattern regimen from the bottomhole to wellhead levels) are discussed.

  12. Terrestrial nitrogen cycles: Some unanswered questions

    Science.gov (United States)

    Vitousek, P.

    1984-01-01

    Nitrogen is generally considered to be the element which most often limits the growth of plants in both natural and agricultural ecosystems. It regulates plant growth because photosynthetic rates are strongly dependent on the concentration of nitrogen in leaves, and because relatively large mounts of protein are required for cell division and growth. Yet nitrogen is abundant in the biosphere - the well-mixed pool in the atmosphere is considered inexhaustible compared to biotic demand, and the amount of already fixed organic nitrogen in soils far exceeds annual plant uptake in terrestrial ecosystems. In regions where natural vegetation is not nitrogen limited, continuous cultivation induces nitrogen deficiency. Nitrogen loss from cultivated lands is more rapid than that of other elements, and nitrogen fertilization is generally required to maintain crop yield under any continuous system. The pervasiveness of nitrogen deficiency in many natural and most managed sites is discussed.

  13. The origin of modern terrestrial life

    Science.gov (United States)

    Forterre, Patrick; Gribaldo, Simonetta

    2007-01-01

    The study of the origin of life covers many areas of expertise and requires the input of various scientific communities. In recent years, this research field has often been viewed as part of a broader agenda under the name of “exobiology” or “astrobiology.” In this review, we have somewhat narrowed this agenda, focusing on the origin of modern terrestrial life. The adjective “modern” here means that we did not speculate on different forms of life that could have possibly appeared on our planet, but instead focus on the existing forms (cells and viruses). We try to briefly present the state of the art about alternative hypotheses discussing not only the origin of life per se, but also how life evolved to produce the modern biosphere through a succession of steps that we would like to characterize as much as possible. PMID:19404443

  14. Geology and Habitability of Terrestrial Planets

    CERN Document Server

    Fishbaugh, Kathryn E; Raulin, François; Marais, David J; Korablev, Oleg

    2007-01-01

    Given the fundamental importance of and universal interest in whether extraterrestrial life has developed or could eventually develop in our solar system and beyond, it is vital that an examination of planetary habitability goes beyond simple assumptions such as, "Where there is water, there is life." This book has resulted from a workshop at the International Space Science Institute (ISSI) in Bern, Switzerland (5-9 September 2005) that brought together planetary geologists, geophysicists, atmospheric scientists, and biologists to discuss the multi-faceted problem of how the habitability of a planet co-evolves with the geology of the surface and interior, the atmosphere, and the magnetosphere. Each of the six chapters has been written by authors with a range of expertise so that each chapter is itself multi-disciplinary, comprehensive, and accessible to scientists in all disciplines. These chapters delve into what life needs to exist and ultimately to thrive, the early environments of the young terrestrial pl...

  15. Terrestrial plant methane production and emission

    DEFF Research Database (Denmark)

    Bruhn, Dan; Møller, Ian M.; Mikkelsen, Teis Nørgaard

    2012-01-01

    aerobic plant CH4 production, i.e. cutting injuries, increasing temperature, ultraviolet radiation and reactive oxygen species. Further, we analyze rates of measured emission of aerobically produced CH4 in pectin and in plant tissues from different studies and argue that pectin is very far from the sole......In this minireview, we evaluate all experimental work published on the phenomenon of aerobic methane (CH4) generation in terrestrial plants and plant. Clearly, despite much uncertainty and skepticism, we conclude that the phenomenon is true. Four stimulating factors have been observed to induce...... aerobic CH4 into a global budget is inadequate. Thus it is too early to draw the line under the aerobic methane emission in plants. Future work is needed for establishing the relative contribution of several proven potential CH4 precursors in plant material....

  16. Cornice Monitoring with a Terrestrial Laser Scanner

    Science.gov (United States)

    Prokop, Alexander; Hancock, Holt

    2017-04-01

    Cornice failure poses a threat to infrastructure and human life in central Svalbard, where cornice fall avalanches comprise a significant portion of all observed avalanche activity. Cornice accretion occurs seasonally on the plateau edges of the mountains that border Longyearbyen - Svalbard's primary settlement - where snow entrained over the long fetches of the plateau summits is deposited by the prevailing winds. Here, we present the preliminary results from our first season regularly monitoring these cornice systems with the Riegl VZ-6000 terrestrial laser scanner. We demonstrate the applicability of TLS data acquisition for monitoring cornice system dynamics and discuss the utility of such measurements for hazard management purposes. Finally, we show how this unique high spatial resolution data will act as a reference dataset for modeling exercises to improve the process understanding of cornice development and failure - in arctic environments and throughout the world.

  17. The Digital Dividend of Terrestrial Broadcasting

    CERN Document Server

    Beutler, Roland

    2012-01-01

    The “digital revolution” of the last two decades has pervaded innumerable aspects of our daily lives and changed our planet irreversibly. The shift from analog to digital broadcasting has facilitated a seemingly infinite variety of new applications—audience interactivity being but one example. The greater efficiency and compression of digital media have endowed broadcasters with a “digital dividend” of spare transmission capacity over and above the requirements of terrestrial broadcasting. The question is, who will use it, and how? Comparing the European experience with that of broadcasters elsewhere in the world, the author sketches the current status of international frequency management, quantifies the value of the “dividend” itself, analyzes the details of the analog-to-digital switchovers already completed, and posits what the future holds for the sector. As we grapple with new devices, inconceivable a mere generation ago, that allow us to access digital media instantly, anywhere and at any...

  18. Nonlinear Waves in the Terrestrial Quasiparallel Foreshock

    Science.gov (United States)

    Hnat, B.; Kolotkov, D. Y.; O'Connell, D.; Nakariakov, V. M.; Rowlands, G.

    2016-12-01

    We provide strongly conclusive evidence that the cubic nonlinearity plays an important part in the evolution of the large amplitude magnetic structures in the terrestrial foreshock. Large amplitude nonlinear wave trains at frequencies above the proton cyclotron frequency are identified after nonharmonic slow variations are filtered out by applying the empirical mode decomposition. Numerical solutions of the derivative nonlinear Schrödinger equation, predicted analytically by the use of a pseudopotential approach, are found to be consistent with the observed wave forms. The approximate phase speed of these nonlinear waves, indicated by the parameters of numerical solutions, is of the order of the local Alfvén speed. We suggest that the feedback of the large amplitude fluctuations on background plasma is reflected in the evolution of the pseudopotential.

  19. Estimation of the hydraulic parameters of a confined geologic formation from slug test in fully penetrating well using a complete quasi-steady flow model in a forward and in an inverse optimal estimation procedure

    Science.gov (United States)

    Rozos, Evangelos; Akylas, Evangelos; Koussis, Antonis D.

    2013-04-01

    Slug tests offer a fast and inexpensive means of estimating the hydraulic parameters of a geologic formation, and are very well suited for contaminated site assessment because no water is essentially withdrawn. In the great majority of slug tests performed in wells fully penetrating confined geologic formations, and for over-damped conditions, the response data are evaluated with the transient-flow model of Cooper et al. (1967) when the radial hydraulic conductivity Kr and the coefficient of specific storage Ss are to be estimated. That particular analytical solution, however, is computationally involved and awkward to use. Thus, groundwater professionals often use a few pre-prepared type-curves to fit the data by a rough matching procedure, visually or computationally. On the other hand, the method of Hvorslev (1951), which assumes the flow to be quasi-steady, is much simpler but yields only Kr-estimates. Koussis and Akylas (2012) have derived a complete quasi-steady flow model that includes a storage balance inside the aquifer and allows estimating both Kr and Ss, through matching of the well response data to a (dimensionless) type-curve. That model approximates the model of Cooper et al. closely and has the practical advantage that its solution type-curves are generated very simply, even using an electronic spreadsheet. Thus, an optimal fit of data by a type-curve can be readily embedded in an exhaustive search. That forward procedure, however, is semi-automated; it involves repeated computation of the quasi-steady flow solution, until finding an optimal pair of Kr and Ss values, according to some formal criterion of optimality, or visually. In addition, we have developed a fully automated inverse procedure for estimating the optimal hydraulic formation parameters Kr and Ss. We test and compare these two parameter estimation methods for the slug test and discuss their strengths and weaknesses. Cooper, H. H., Jr., J. D. Bredehoeft and I. S. Papadopulos. 1967

  20. Grazing livestock are exposed to terrestrial cyanobacteria.

    Science.gov (United States)

    McGorum, Bruce C; Pirie, R Scott; Glendinning, Laura; McLachlan, Gerry; Metcalf, James S; Banack, Sandra A; Cox, Paul A; Codd, Geoffrey A

    2015-02-25

    While toxins from aquatic cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial cyanobacteria has not been described. This study identified terrestrial cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 grazing horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of grazing horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the cyanobacterial neurotoxins β-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in grazing horses. However, further study is warranted to identify and quantify toxins produced by cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in grazing livestock.

  1. Future hotspots of terrestrial mammal loss

    Science.gov (United States)

    Visconti, Piero; Pressey, Robert L.; Giorgini, Daniele; Maiorano, Luigi; Bakkenes, Michel; Boitani, Luigi; Alkemade, Rob; Falcucci, Alessandra; Chiozza, Federica; Rondinini, Carlo

    2011-01-01

    Current levels of endangerment and historical trends of species and habitats are the main criteria used to direct conservation efforts globally. Estimates of future declines, which might indicate different priorities than past declines, have been limited by the lack of appropriate data and models. Given that much of conservation is about anticipating and responding to future threats, our inability to look forward at a global scale has been a major constraint on effective action. Here, we assess the geography and extent of projected future changes in suitable habitat for terrestrial mammals within their present ranges. We used a global earth-system model, IMAGE, coupled with fine-scale habitat suitability models and parametrized according to four global scenarios of human development. We identified the most affected countries by 2050 for each scenario, assuming that no additional conservation actions other than those described in the scenarios take place. We found that, with some exceptions, most of the countries with the largest predicted losses of suitable habitat for mammals are in Africa and the Americas. African and North American countries were also predicted to host the most species with large proportional global declines. Most of the countries we identified as future hotspots of terrestrial mammal loss have little or no overlap with the present global conservation priorities, thus confirming the need for forward-looking analyses in conservation priority setting. The expected growth in human populations and consumption in hotspots of future mammal loss mean that local conservation actions such as protected areas might not be sufficient to mitigate losses. Other policies, directed towards the root causes of biodiversity loss, are required, both in Africa and other parts of the world. PMID:21844048

  2. The terrestrial biosphere in the SFR region

    Energy Technology Data Exchange (ETDEWEB)

    Jerling, L.; Isaeus, M. [Stockholm Univ. (Sweden). Dept. of Botany; Lanneck, J. [Stockholm Univ. (Sweden). Dept. of Physical Geography; Lindborg, T.; Schueldt, R. [Danish Nature Council, Copenhagen (Denmark)

    2001-03-01

    This report is a part of the SKB project 'SAFE' (Safety Assessment of the Final Repository of Radioactive Operational Waste). The aim of project SAFE is to update the previous safety analysis of SFR-1.SFR-1 is a facility for disposal of low and intermediate level radioactive waste, which is situated in bedrock beneath the Baltic Sea, one km off the coast near the Forsmark nuclear power plant in Northern Uppland. A part of the SAFE-analysis aims at analysing the transport of radionuclides in the ecosystems.To do so one has to build a model that includes a large amount of information concerning the biosphere.The first step is to collect and compile descriptions of the biosphere.This report is a first attempt to characterise the terrestrial environment of the SFR area of Forsmark. In the first part of the report the terrestrial environment, land class distribution and production of the area is described. The primary production in different terrestrial ecosystems is estimated for a model area in the Forsmark region. The estimations are based on the actual land class distribution and the values for the total primary production (d.w. above ground biomass)and the amount carbon produced, presented as g/m{sup 2} for each land class respectively. An important aspect of the biosphere is the vegetation and its development. The future development of vegetation is of interest since production,decomposition and thus storage of organic material, vary strongly among vegetation types and this has strong implications for the transport of radionuclides.Therefore an attempt to describe the development of terrestrial vegetation has been made in the second part. Any prediction of future vegetation is based on knowledge of the past together with premises for the future development.The predictions made, thus, becomes marred with errors enforced by the assumptions and incomplete information of the past. The assumptions made for the predictions in this report are crude and results

  3. Cascading effects of induced terrestrial plant defences on aquatic and terrestrial ecosystem function.

    Science.gov (United States)

    Jackrel, Sara L; Wootton, J Timothy

    2015-04-22

    Herbivores induce plants to undergo diverse processes that minimize costs to the plant, such as producing defences to deter herbivory or reallocating limited resources to inaccessible portions of the plant. Yet most plant tissue is consumed by decomposers, not herbivores, and these defensive processes aimed to deter herbivores may alter plant tissue even after detachment from the plant. All consumers value nutrients, but plants also require these nutrients for primary functions and defensive processes. We experimentally simulated herbivory with and without nutrient additions on red alder (Alnus rubra), which supplies the majority of leaf litter for many rivers in western North America. Simulated herbivory induced a defence response with cascading effects: terrestrial herbivores and aquatic decomposers fed less on leaves from stressed trees. This effect was context dependent: leaves from fertilized-only trees decomposed most rapidly while leaves from fertilized trees receiving the herbivory treatment decomposed least, suggesting plants funnelled a nutritionally valuable resource into enhanced defence. One component of the defence response was a decrease in leaf nitrogen leading to elevated carbon : nitrogen. Aquatic decomposers prefer leaves naturally low in C : N and this altered nutrient profile largely explains the lower rate of aquatic decomposition. Furthermore, terrestrial soil decomposers were unaffected by either treatment but did show a preference for local and nitrogen-rich leaves. Our study illustrates the ecological implications of terrestrial herbivory and these findings demonstrate that the effects of selection caused by terrestrial herbivory in one ecosystem can indirectly shape the structure of other ecosystems through ecological fluxes across boundaries. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  4. Divergent apparent temperature sensitivity of terrestrial ecosystem respiration

    Science.gov (United States)

    Bing Song; Shuli Niu; Ruise Luo; Yiqi Luo; Jiquan Chen; Guirui Yu; Janusz Olejnik; Georg Wohlfahrt; Gerard Kiely; Ako Noormets; Leonardo Montagnani; Alessandro Cescatti; Vincenzo Magliulo; Beverly Elizabeth Law; Magnus Lund; Andrej Varlagin; Antonio Raschi; Matthias Peichl; Mats B. Nilsson; Lutz Merbold

    2014-01-01

    Recent studies revealed convergent temperature sensitivity of ecosystem respiration (Re) within aquatic ecosystems and between terrestrial and aquatic ecosystems. We do not know yet whether various terrestrial ecosystems have consistent or divergent temperature sensitivity. Here, we synthesized 163 eddy covariance flux sites across the world and...

  5. Water use efficiency of net primary production in global terrestrial ...

    Indian Academy of Sciences (India)

    Water use efficiency; global terrestrial ecosystems; MODIS; net primary production; evapotranspiration;. Köppen–Geiger climate classification. ... Terrestrial plants fix or trap carbon dioxide via photosynthesis to produce the material ...... S W 2007 Evaluating water stress controls on primary production in biogeochemical and ...

  6. Climate control of terrestrial carbon exchange across biomes and continents

    Science.gov (United States)

    Chuixiang Yi; Daniel Ricciuto; Runze Li; John Wolbeck; Xiyan Xu; Mats Nilsson; John Frank; William J. Massman

    2010-01-01

    Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate-carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO2 exchange with the atmosphere across biomes...

  7. The decadal state of the terrestrial carbon cycle

    NARCIS (Netherlands)

    Velde, van der I.R.; Bloom, J.; Exbrayat, J.; Feng, L.; Williams, M.

    2016-01-01

    The terrestrial carbon cycle is currently the least constrained component of the global carbon budget. Large uncertainties stem from a poor understanding of plant carbon allocation, stocks, residence times, and carbon use efficiency. Imposing observational constraints on the terrestrial carbon cycle

  8. Estimation of evapotranspiration over the terrestrial ecosystems in China

    Science.gov (United States)

    Xianglan Li; Shunlin Liang; Wenping Yuan; Guirui Yu; Xiao Cheng; Yang Chen; Tianbao Zhao; Jinming Feng; Zhuguo Ma; Mingguo Ma; Shaomin Liu; Jiquan Chen; Changliang Shao; Shenggong Li; Xudong Zhang; Zhiqiang Zhang; Ge Sun; Shiping Chen; Takeshi Ohta; Andrej Varlagin; Akira Miyata; Kentaro Takagi; Nobuko Saiqusa; Tomomichi Kato

    2014-01-01

    Quantifying regional evapotranspiration (ET) and environmental constraints are particularly important for understanding water and carbon cycles of terrestrial ecosystems. However, a large uncertainty in the regional estimation of ET still remains for the terrestrial ecosystems in China. This study used ET measurements of 34 eddy covariance sites within China and...

  9. Plant reproductive organs and the origin of terrestrial insects

    Science.gov (United States)

    Georgy V. Stadnitsky

    1991-01-01

    It is widely believed that plants facilitated the evolution of terrestrial insects (Southwood 1973). However, the mechanisms by which this evolution occurred are not yet fully understood. I therefore propose a hypothesis about one possible mode of formation of terrestrial insects and fauna. The soil, warm shallow lagoons, tidal zones, and accumulations of detritus are...

  10. Water use efficiency of net primary production in global terrestrial ...

    Indian Academy of Sciences (India)

    The carbon and water cycles of terrestrial ecosystems, which are strongly coupled via water use efficiency (WUE), are influenced by global climate change. To explore the relationship between the carbon and water cycles and predict the effect of climate change on terrestrial ecosystems, it is necessary to study the WUE in ...

  11. The early evolution of the atmospheres of terrestrial planets

    CERN Document Server

    Raulin, François; Muller, Christian; Nixon, Conor; Astrophysics and Space Science Proceedings : Volume 35

    2013-01-01

    “The Early Evolution of the Atmospheres of Terrestrial Planets” presents the main processes participating in the atmospheric evolution of terrestrial planets. A group of experts in the different fields provide an update of our current knowledge on this topic. Several papers in this book discuss the key role of nitrogen in the atmospheric evolution of terrestrial planets. The earliest setting and evolution of planetary atmospheres of terrestrial planets is directly associated with accretion, chemical differentiation, outgassing, stochastic impacts, and extremely high energy fluxes from their host stars. This book provides an overview of the present knowledge of the initial atmospheric composition of the terrestrial planets. Additionally it includes some papers about the current exoplanet discoveries and provides additional clues to our understanding of Earth’s transition from a hot accretionary phase into a habitable world. All papers included were reviewed by experts in their respective fields. We are ...

  12. Terrestrial short-term ecotoxicity of a green formicide.

    Science.gov (United States)

    Tiepo, Erasmo N; Corrêa, Albertina X R; Resgalla, Charrid; Cotelle, Sylvie; Férard, Jean-François; Radetski, Claudemir M

    2010-07-01

    When ants become annoying, large quantities of formicide are applied to terrestrial ecosystems in tropical regions, but awareness of the health and environmental impacts related to the use of synthetic pesticides has been increasing. The use of green pesticides to combat target organisms could reduce these impacts. In this regard, terrestrial ecotoxicity tests with higher plants (Brassica olaracea, Lactuca sativa and Mucuna aterrima), annelids (Eisenia foetida), Collembola (Folsomia candida) and soil enzyme activity analysis (diacetate fluorescein hydrolysis) were used to evaluate short-term terrestrial ecotoxicity of a green pesticide prepared from naturally-occurring organic compounds. At the highest formicide concentration tested in these experiments (i.e., 50 g kg(-1) soil) no toxicity toward terrestrial organisms was observed. The lack of short-term terrestrial ecotoxicity suggest that this green formicide can be classed as an environmentally friendly product as compared to the ecotoxicity of the most commonly used commercialized formicides. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  13. The decadal state of the terrestrial carbon cycle : Global retrievals of terrestrial carbon allocation, pools, and residence times

    NARCIS (Netherlands)

    Bloom, A Anthony; Exbrayat, Jean-François; van der Velde, Ivar R; Feng, Liang; Williams, Mathew

    2016-01-01

    The terrestrial carbon cycle is currently the least constrained component of the global carbon budget. Large uncertainties stem from a poor understanding of plant carbon allocation, stocks, residence times, and carbon use efficiency. Imposing observational constraints on the terrestrial carbon cycle

  14. Estimating Exposure of Terrestrial Wildlife to Contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Sample, B.E.

    1994-01-01

    This report presents a general model for exposure of terrestrial wildlife to contaminants (Sect. 2), methods for estimating parameters of the model (Sect. 3), species specific parameters for endpoint species on the Oak Ridge Reservation (ORR) (Sect. 4), and a sample application (Sect. 5). Exposure can be defined as the coincidence in both space and time of a receptor and a stressor, such that the receptor and stressor come into contact and interact (Risk Assessment Forum 1992). In the context of ecological risk assessment, receptors include all endpoint species or communities identified for a site [see Suter (1989) and Suter et al. (1994) for discussions of ecological endpoints for waste sites]. In the context of waste site assessments, stressors are chemical contaminations, and the contact and interaction are uptake of the contaminant by the receptor. Without sufficient exposure of the receptor to the contaminants, there is no ecological risk. Unlike some other endpoint assemblages, terrestrial wildlife are significantly exposed to contaminants in multiple media. They may drink or swim in contaminated water, ingest contaminated food and soil, and breath contaminated air. In addition, because most wildlife are mobile, moving among and within habitats, exposure is not restricted to a single location. They may integrate contamination from several spatially discrete sources. Therefore, exposure models for terrestrial wildlife must include multiple media. This document provides models and parameters for estimating exposure of birds and mammals. Reptiles and amphibians are not considered because few data exist with which to assess exposure to these organisms. In addition, because toxicological data are scarce for both classes, evaluation of the significance of exposure estimates is problematic. However, the general exposure estimation procedure developed herein for birds and mammals is applicable to reptiles and amphibians. Exposure models must be appropriate to the

  15. Ecoulements diphasiques gaz-liquide à poches et à bouchons en conduites Two-Phase Gas-Liquid Slug Flow in Pipes

    Directory of Open Access Journals (Sweden)

    Ferschneider G.

    2006-11-01

    Full Text Available Les écoulements diphasiques gaz-liquide ont été étudiés afin de contribuer à développer des modèles de calculs prédictifs des pertes de charge dans les conduites de production des bruts pétroliers. Les expériences nécessaires ont été réalisées sur la boucle diphasique de Boussens dans les conditions suivantes représentatives des conditions industrielles : diamètre 6 , longueur 120 m, disposition de la conduite horizontale ou faiblement ascendante, couple de fluide gaz naturel-huile légère. Le gradient de pression, le contenu global, et la distribution locale des phases ont été mesurés. Le traitement des équations de conservation phasique intégrées sur la section par différents types de moyennes a permis de développer un modèle cellulaire qui inclue un nombre limité d'équations constitutives nécessaires à sa fermeture. Ce modèle prédétermine convenablement le gradient de pression, le contenu gaz global et la longueur des poches et des bouchons. Two-phase gas-liquid flows were analyzed so as to develop models for prediction of pressure drops in crude-oil production lines. The experiments were performed on the two-phase loop at Boussens under the following representative industrial conditions: 6 diameter, 120 m length, horizontal or slightly rising pipe, couple of fluids natural gas and light oil. The pressure gradient, average content and local phase distribution were measured. Conservation phase equations integrated along the cross-section were processed by different time-averaged operators so as to develop a cellular model including a limited number of constitutive equations required for its closure. This model suitably predetermines the pressure gradient, the average gas content and the length of gas and liquid slug.

  16. Evaluation of the MERIS terrestrial Chlorophyll Index

    Science.gov (United States)

    Dash, J.; Curran, P.

    The MEdium Resolution Imaging Spectrometer (MERIS), one of the payloads on Envisat, has fine spectral resolution, moderate spatial resolution and a three day repeat cycle. This makes MERIS a potentially valuable sensor for the measurement and monitoring of terrestrial environments at regional to global scales. The red edge, which results from an abrupt change in reflectance in red and near-infrared wavelengths has a location that is related directly to the chlorophyll content of vegetation. A new index called the MERIS terrestrial chlorophyll index (MTCI) uses data in three red and NIR wavebands centred at 681.25nm, 705nm and 753.75nm (bands 8, 9 and 10 in the MERIS standard band setting). The MTCI is easy to calculate and can be automated. Preliminary indirect evaluation using model, field and MERIS data suggested its sensitivity, notably to high values of chlorophyll content and its limited sensitivity to spatial resolution and atmospheric effects. As a result this index is now a standard level-2 product of the European Space Agency. For direct MTCI evaluation two different approaches were used. First, the MTCI/chlorophyll content relationship were determined using a surrogate of chlorophyll content for sites in southern Vietnam and second, the MTCI/chlorophyll relationship was determined using actual chlorophyll content for sites in the New Forest, UK and for plots in a greenhouse. Forests in southern Vietnam were contaminated heavily with Agent Orange during the Vietnam War. The contamination levels were so high that it led to a long term decrease in chlorophyll content within forests that have long since regained full canopy cover. In this approach the amount of Agent Orange dropped onto the forest between 1965 and 1971 was used as a surrogate for contemporary chlorophyll content and was related to current MTCI at selected forest sites. The resulting relationship was positive. Further per pixel investigation of the MTCI/Agent Orange concentration relationship

  17. The Valanginian terrestrial carbon-isotope record

    Science.gov (United States)

    Grocke, D. R.; Price, G. D.; Baraboshkin, E.; Mutterlose, J.; Ruffell, A. H.

    2003-04-01

    A stratigraphic, biostratigraphic and isotopic investigation has been performed on a Crimean section located on the Kacha River, Verkhorechie Village, SW Crimea. This clastic-dominated succession consists of a series of bioturbated inter-bedded shallow-marine silty sands, claystones and some oolitic sands. A published detailed study of the ammonite fauna has been undertaken and has revealed that the succession can be compared to standard Tethyan schemes. The lower part of the succession is dated on the basis of the ammonite fauna as Early Valanginian (otopeta-campylotoxus ammonite Zones), although this latter zone is highly condensed. A more expanded Late Valanginian is present (verrucosum, callidiscus and tauricum ammonite Zones), and is overlain by sand-dominated sediments of Early Hauterivian age. Throughout this section woody plant matter ranging in preservation from charcoal to coal has been collected and analyzed for stable carbon-isotope ratios. There is no correlation between state of preservation and carbon-isotope ratios. Carbon-isotope ratios range in the Early Valanginian from -24 ppm to -22 ppm, and in the mid-verrucosum Zone values shift abruptly towards more positive values and peak at -18 ppm in the lower callidiscus Zone. Wood carbon-isotope ratios decrease gradually through the remainder of the callidiscus Zone and return to pre-excursion values in the tauricum Zone. The remaining Hauterivian values fluctuate between -24 ppm to -21 ppm. The structure, magnitude and timing of the terrestrial carbon-isotope curve is very similar to the marine carbonate curve (from +1 ppm to +3 ppm) for the Valanginian. This would indicate, based on a delta-delta relationship between organic matter and carbonate, that there was very little change in atmospheric CO_2 concentrations during the Valanginian, and that the isotopic composition of the global carbon reservoir shifted. Future research on an Early Cretaceous (Valanginian-Hauterivian) interval from the Yatria

  18. Terrestrial Ages of Antarctic Meteorites: Up Date 1999

    Science.gov (United States)

    Nishiizumi, K.; Caffee, M. W.; Welten, K. C.

    2000-01-01

    We are continuing our ongoing study of cosmogenic nuclides in Antarctic meteorites. In addition to the studies of exposure histories of meteorites, we study terrestrial ages and pairing of Antarctic meteorites and desert meteorites. Terrestrial ages of Antarctic meteorites provide information on meteorite accumulation mechanisms, mean weathering lifetimes, and influx rates. The determination of Cl-36 (half-life=3.01 x 10(exp 5) y) terrestrial ages is one of our long-term on-going projects, however, in many instances neither Cl-36 or C-14 (5,730 y) yields an accurate terrestrial age. Using Ca-41 (1.04 x 10(exp 5) y) for terrestrial age determinations solves this problem by filling the gap in half-life between C-14 and Cl-36 ages. We are now applying the new Ca-41 - Cl-36 terrestrial age method as well as the Cl-36 - Be-10 method to Antarctic meteorites. Our measurements and C-14 terrestrial age determinations by the University of Arizona group are always complementary.

  19. Biomass allocation patterns across China's terrestrial biomes.

    Directory of Open Access Journals (Sweden)

    Limei Wang

    Full Text Available Root to shoot ratio (RS is commonly used to describe the biomass allocation between below- and aboveground parts of plants. Determining the key factors influencing RS and interpreting the relationship between RS and environmental factors is important for biological and ecological research. In this study, we compiled 2088 pairs of root and shoot biomass data across China's terrestrial biomes to examine variations in the RS and its responses to biotic and abiotic factors including vegetation type, soil texture, climatic variables, and stand age. The median value of RS (RSm for grasslands, shrublands, and forests was 6.0, 0.73, and 0.23, respectively. The range of RS was considerably wide for each vegetation type. RS values for all three major vegetation types were found to be significantly correlated to mean annual precipitation (MAP and potential water deficit index (PWDI. Mean annual temperature (MAT also significantly affect the RS for forests and grasslands. Soil texture and forest origin altered the response of RS to climatic factors as well. An allometric formula could be used to well quantify the relationship between aboveground and belowground biomass, although each vegetation type had its own inherent allometric relationship.

  20. Biomass allocation patterns across China's terrestrial biomes.

    Science.gov (United States)

    Wang, Limei; Li, Longhui; Chen, Xi; Tian, Xin; Wang, Xiaoke; Luo, Geping

    2014-01-01

    Root to shoot ratio (RS) is commonly used to describe the biomass allocation between below- and aboveground parts of plants. Determining the key factors influencing RS and interpreting the relationship between RS and environmental factors is important for biological and ecological research. In this study, we compiled 2088 pairs of root and shoot biomass data across China's terrestrial biomes to examine variations in the RS and its responses to biotic and abiotic factors including vegetation type, soil texture, climatic variables, and stand age. The median value of RS (RSm) for grasslands, shrublands, and forests was 6.0, 0.73, and 0.23, respectively. The range of RS was considerably wide for each vegetation type. RS values for all three major vegetation types were found to be significantly correlated to mean annual precipitation (MAP) and potential water deficit index (PWDI). Mean annual temperature (MAT) also significantly affect the RS for forests and grasslands. Soil texture and forest origin altered the response of RS to climatic factors as well. An allometric formula could be used to well quantify the relationship between aboveground and belowground biomass, although each vegetation type had its own inherent allometric relationship.

  1. Sagebrush Biomass Estimation Using Terrestrial Laser Scanning

    Science.gov (United States)

    Olsoy, P.; Glenn, N. F.; Clark, P. E.; Spaete, L.; Mitchell, J.; Shrestha, R.

    2012-12-01

    LiDAR (Light Detection and Ranging) is a proven tool for inventory of many vegetation types. Airborne laser scanning (ALS) has been demonstrated for estimation of biomass of trees, but the relatively low number of laser points (1-10 m-2) typical of ALS datasets makes estimating biomass of shrubs and small stature vegetation challenging. This study uses terrestrial laser scanning (TLS) to estimate sagebrush biomass (Artemisia tridentata subsp. wyomingensis) by relating destructively sampled estimates to TLS-derived volumetric estimates. At close range, TLS can commonly provide in excess of 100,000 3-D points for a single sagebrush of approximately 1 m3 in volume. In this study, thirty sagebrush were scanned and destructively sampled at 6 sites within Reynolds Creek Experimental Watershed in southwestern Idaho, USA. The 3-D point cloud data are converted into 1-cm voxels to give quantitative estimates of shrub volume. The accuracy of the TLS-based metrics for estimating biomass are then compared to several traditional plot sampling methods including point-intercept and simple crown dimension measurements. The findings of this study are expected to provide guidance on methods for data collection and analysis such that biomass can be accurately estimated across plot-scales (e.g., 100 m x 100 m).

  2. Energetics of the terrestrial bow shock

    Science.gov (United States)

    Hamrin, Maria; Gunell, Herbert; Norqvist, Patrik

    2017-04-01

    The solar wind is the primary energy source for the magnetospheric energy budget. Energy can enter through the magnetopause both as kinetic energy (plasma entering via e.g. magnetic reconnection and impulsive penetration) and as electromagnetic energy (e.g. by the conversion of solar wind kinetic energy into electromagnetic energy in magnetopause generators). However, energy is extracted from the solar wind already at the bow shock, before it encounters the terrestrial magnetopause. At the bow shock the supersonic solar wind is slowed down and heated, and the region near the bow shock is known to host many complex processes, including the accelerating of particles and the generation of waves. The processes at and near the bow shock can be discussed in terms of energetics: In a generator (load) process kinetic energy is converted to (from) electromagnetic energy. Bow shock regions where the solar wind is decelerated correspond to generators, while regions where particles are energized (accelerated and heated) correspond to loads. Recently, it has been suggested that currents from the bow shock generator should flow across the magnetosheath and connect to the magnetospause current systems [Siebert and Siscoe, 2002; Lopez et al., 2011]. In this study we use data from the Magnetospheric MultiScale (MMS) mission to investigate the energetics of the bow shock and the current closure, and we compare with the MHD simulations of Lopez et al., 2011.

  3. Patterns of taxonomic diversity among terrestrial isopods

    Directory of Open Access Journals (Sweden)

    Spyros Sfendourakis

    2015-07-01

    Full Text Available The publication of the world catalog of terrestrial isopods some ten years ago by Schmalfuss has facilitated research on isopod diversity patterns at a global scale. Furthermore, even though we still lack a comprehensive and robust phylogeny of Oniscidea, we do have some useful approaches to phylogenetic relationships among major clades which can offer additional insights into isopod evolutionary dynamics. Taxonomic diversity is one of many approaches to biodiversity and, despite its sensitiveness to biases in taxonomic practice, has proved useful in exploring diversification dynamics of various taxa. In the present work, we attempt an analysis of taxonomic diversity patterns among Oniscidea based on an updated world list of species containing 3,710 species belonging to 527 genera and 37 families (data till April 2014. The analysis explores species diversity at the genus and family level, as well as the relationships between species per genera, species per families, and genera per families. In addition, we consider the structure of isopod taxonomic system under the fractal perspective that has been proposed as a measure of a taxon’s diversification. Finally, we check whether there is any phylogenetic signal behind taxonomic diversity patterns. The results can be useful in a more detailed elaboration of Oniscidea systematics.

  4. Terrestrial vegetation dynamics and global climate controls

    Energy Technology Data Exchange (ETDEWEB)

    Potter, Christopher [NASA Ames Research Center, Moffett Field, CA (United States); Boriah, Shyam; Steinbach, Michael; Kumar, Vipin [University of Minnesota, Minneapolis, MN (United States); Klooster, Steven [California State University Monterey Bay, Seaside, CA (United States)

    2008-07-15

    Monthly data from the moderate resolution imaging spectroradiometer (MODIS) and its predecessor satellite sensors was used to reconstruct vegetation dynamics in response to climate patterns over the period 1983-2005. Results suggest that plant growth over extensive land areas of southern Africa and Central Asia were the most closely coupled of any major land area to El Nino-southern oscillation (ENSO) effects on regional climate. Others land areas strongly tied to recent ENSO climate effects were in northern Canada, Alaska, western US, northern Mexico, northern Argentina, and Australia. Localized variations in precipitation were the most common controllers of monthly values for the fraction absorbed of photosynthetically active radiation (FPAR) over these regions. In addition to the areas cited above, seasonal FPAR values from MODIS were closely coupled to rainfall patterns in grassland and cropland areas of the northern and central US. Historical associations between global vegetation FPAR and atmospheric carbon dioxide (CO{sub 2}) anomalies suggest that the terrestrial biosphere can contribute major fluxes of CO{sub 2} during major drought events, such as those triggered by 1997-1998 El Nino event. (orig.)

  5. Mapping and Quantifying Terrestrial Vertebrate Biodiversity at ...

    Science.gov (United States)

    The ability to assess, report, map, and forecast functions of ecosystems is critical to our capacity to make informed decisions to maintain the sustainable nature of our environment. Because of the variability among living organisms and levels of organization (e.g. genetic, species, ecosystem), biodiversity has always been difficult to measure precisely, especially within a systematic manner and over multiple scales. In answer to this challenge, the U.S. Environmental Protection Agency has created a partnership with other Federal agencies, academic institutions, and Non-Governmental Organizations to develop the EnviroAtlas (https://www.epa.gov/enviroatlas), an online national Decision Support Tool that allows users to view and analyze the geographical description of the supply and demand for ecosystem services, as well as the drivers of change. As part of the EnviroAtlas, an approach has been developed that uses deductive habitat models for all terrestrial vertebrates of the conterminous United States and clusters them into biodiversity metrics that relate to ecosystem service-relevant categories. Metrics, such as species and taxon richness, have been developed and integrated with other measures of biodiversity. Collectively, these metrics provide a consistent scalable process from which to make geographic comparisons, provide thematic assessments, and to monitor status and trends in biodiversity. The national biodiversity component operates across approximatel

  6. Sampling supraglacial debris thickness using terrestrial photogrammetry

    Science.gov (United States)

    Nicholson, Lindsey; Mertes, Jordan

    2017-04-01

    The melt rate of debris-covered ice differs to that of clean ice primarily as a function of debris thickness. The spatial distribution of supraglacial debris thickness must therefore be known in order to understand how it is likely to impact glacier behaviour, and meltwater contribution to local hydrological resources and global sea level rise. However, practical means of determining debris cover thickness remain elusive. In this study we explore the utility of terrestrial photogrammetry to produce high resolution, scaled and texturized digital terrain models of debris cover exposures above ice cliffs as a means of quantifying and characterizing debris thickness. Two Nikon D5000 DSLRs with Tamron 100mm lenses were used to photograph a sample area of the Ngozumpa glacier in the Khumbu Himal of Nepal in April 2016. A Structure from Motion workflow using Agisoft Photoscan software was used to generate a surface models with manual point measurements along the same clifftops. We conclude that sufficiently high resolution photogrammetry, with precise scaling information, provides a useful means to determine debris thickness at clifftop exposures. The resolution of the possible measurements depends on image resolution, the accuracy of the ground control points and the computational capacity to generate centimetre scale surface models. Application of such techniques to sufficiently high resolution imagery from UAV-borne cameras may offer a powerful means of determining debris thickness distribution patterns over debris covered glacier termini.

  7. Dinosaurs and the Cretaceous Terrestrial Revolution

    Science.gov (United States)

    Lloyd, Graeme T; Davis, Katie E; Pisani, Davide; Tarver, James E; Ruta, Marcello; Sakamoto, Manabu; Hone, David W.E; Jennings, Rachel; Benton, Michael J

    2008-01-01

    The observed diversity of dinosaurs reached its highest peak during the mid- and Late Cretaceous, the 50 Myr that preceded their extinction, and yet this explosion of dinosaur diversity may be explained largely by sampling bias. It has long been debated whether dinosaurs were part of the Cretaceous Terrestrial Revolution (KTR), from 125–80 Myr ago, when flowering plants, herbivorous and social insects, squamates, birds and mammals all underwent a rapid expansion. Although an apparent explosion of dinosaur diversity occurred in the mid-Cretaceous, coinciding with the emergence of new groups (e.g. neoceratopsians, ankylosaurid ankylosaurs, hadrosaurids and pachycephalosaurs), results from the first quantitative study of diversification applied to a new supertree of dinosaurs show that this apparent burst in dinosaurian diversity in the last 18 Myr of the Cretaceous is a sampling artefact. Indeed, major diversification shifts occurred largely in the first one-third of the group's history. Despite the appearance of new clades of medium to large herbivores and carnivores later in dinosaur history, these new originations do not correspond to significant diversification shifts. Instead, the overall geometry of the Cretaceous part of the dinosaur tree does not depart from the null hypothesis of an equal rates model of lineage branching. Furthermore, we conclude that dinosaurs did not experience a progressive decline at the end of the Cretaceous, nor was their evolution driven directly by the KTR. PMID:18647715

  8. Transfer coefficients for terrestrial foodchain: their derivation and limitations

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Y.C.; Colsher, C.S.; Thompson, S.E.

    1979-03-30

    Transfer coefficients to predict the passage of isotopes from the environment to terrestrial foods have been derived for various radionuclides of importance in the nuclear fuel cycle. These data update and extend previously recommended handbook values. We derive transfer coefficients to terrestrial foods and describe the systematics of the derived transfer coefficients. Suggestions are offered for changes in the values of transfer coefficients to terrestrial foods that now appear in federal regulatory guides. Deficiencies in our present knowledge concerning transfer coefficients and limitations in the use of these values to ensure compliance with radiation protection standards are discussed.

  9. Chains, bombs, potrzebies and slugs

    Science.gov (United States)

    Jewess, Mike; McDowell, Alex; Maxfield, Stephen; Hunt, A. G.; Hicks, Bruce

    2010-03-01

    I read with pleasure Robert Crease's article on unusual units (February pp17-19). However, the article stated that an acre is 10×10 chains, when it is in fact 10×1 chains. Incidentally, a distance of 10 chains (220 yards) is known as a furlong, a word that suggests the length of a ploughed furrow and that is still used in horse-racing.

  10. Biological control of the terrestrial carbon sink

    Directory of Open Access Journals (Sweden)

    E.-D. Schulze

    2006-01-01

    Full Text Available This lecture reviews the past (since 1964 when the International Biological Program began and the future of our understanding of terrestrial carbon fluxes with focus on photosynthesis, respiration, primary-, ecosystem-, and biome-productivity. Photosynthetic capacity is related to the nitrogen concentration of leaves, but the capacity is only rarely reached under field conditions. Average rates of photosynthesis and stomatal conductance are closely correlated and operate near 50% of their maximal rate, with light being the limiting factor in humid regions and air humidity and soil water the limiting factor in arid climates. Leaf area is the main factor to extrapolate from leaves to canopies, with maximum surface conductance being dependent on leaf level stomatal conductance. Additionally, gas exchange depends also on rooting depth which determines the water and nutrient availability and on mycorrhizae which regulate the nutrient status. An important anthropogenic disturbance is the nitrogen uptake from air pollutants, which is not balanced by cation uptake from roots and this may lead to damage and breakdown of the plant cover. Photosynthesis is the main carbon input into ecosystems, but it alone does not represent the ecosystem carbon balance, which is determined by respiration of various kinds. Plant respiration and photosynthesis determine growth (net primary production and microbial respiration balances the net ecosystem flux. In a spruce forest, 30% of the assimilatory carbon gain is used for respiration of needles, 20% is used for respiration in stems. Soil respiration is about 50% the carbon gain, half of which is root respiration, half is microbial respiration. In addition, disturbances lead to carbon losses, where fire, harvest and grazing bypass the chain of respiration. In total, the carbon balance at the biome level is only about 1% of the photosynthetic carbon input, or may indeed become negative. The recent observed increase in

  11. Biological control of the terrestrial carbon sink

    Science.gov (United States)

    Schulze, E.-D.

    2006-03-01

    This lecture reviews the past (since 1964 when the International Biological Program began) and the future of our understanding of terrestrial carbon fluxes with focus on photosynthesis, respiration, primary-, ecosystem-, and biome-productivity. Photosynthetic capacity is related to the nitrogen concentration of leaves, but the capacity is only rarely reached under field conditions. Average rates of photosynthesis and stomatal conductance are closely correlated and operate near 50% of their maximal rate, with light being the limiting factor in humid regions and air humidity and soil water the limiting factor in arid climates. Leaf area is the main factor to extrapolate from leaves to canopies, with maximum surface conductance being dependent on leaf level stomatal conductance. Additionally, gas exchange depends also on rooting depth which determines the water and nutrient availability and on mycorrhizae which regulate the nutrient status. An important anthropogenic disturbance is the nitrogen uptake from air pollutants, which is not balanced by cation uptake from roots and this may lead to damage and breakdown of the plant cover. Photosynthesis is the main carbon input into ecosystems, but it alone does not represent the ecosystem carbon balance, which is determined by respiration of various kinds. Plant respiration and photosynthesis determine growth (net primary production) and microbial respiration balances the net ecosystem flux. In a spruce forest, 30% of the assimilatory carbon gain is used for respiration of needles, 20% is used for respiration in stems. Soil respiration is about 50% the carbon gain, half of which is root respiration, half is microbial respiration. In addition, disturbances lead to carbon losses, where fire, harvest and grazing bypass the chain of respiration. In total, the carbon balance at the biome level is only about 1% of the photosynthetic carbon input, or may indeed become negative. The recent observed increase in plant growth has

  12. A Microseismometer for Terrestrial and Extraterrestrial Applications

    Science.gov (United States)

    Banerdt, W.; Kaiser, W.; Vanzandt, T.

    1993-01-01

    The scientific and technical requirements of extraterrestrial seismology place severe demands on instrumentation. Performance in terms of sensitivity, stability, and frequency band must match that of the best terrestrial instruments, at a fraction of the size, mass, and power. In addition, this performance must be realized without operator intervention in harsh temperature, shock, and radiation environments. These constraints have forced us to examine some fundamental limits of accelerometer design in order to produce a small, rugged, sensitive seismometer. Silicon micromachined sensor technology offers techniques for the fabrication of monolithic, robust, compact, low-power and -mass accelerometers. However, currently available sensors offer inadequate sensitivity and bandwidth. Our implementation of an advanced silicon micro machined seismometer is based on principles developed at JPL for high-sensitivity position sensor technology. The use of silicon micro machining technology with these new principles should enable the fabrication of a 10(exp -11) g sensitivity seismometer with a bandwidth of at least 0.01 to 20 Hz. The low Q properties of pure single-crystal silicon are essential in order to minimize the Brownian thermal noise limitations generally characteristic of seismometers with small proof masses. A seismometer consists of a spring-supported proof mass and a transducer for measuring its motion. For long period motion a position sensor is generally used, for which the displacement is proportional to the ground acceleration. The mechanical sensitivity can be increased either by increasing the proof mass or decreasing the spring stiffness, neither of which is desirable for planetary applications. Our approach has been to use an ultra sensitive capacitive position sensor with a sensitivity of better than 10(exp -13) m/Hz(exp 1/2). This allows the use of a stiffer suspension and a smaller proof mass. We have built several prototypes using these principles

  13. Topographic-driven instabilities in terrestrial bodies

    Science.gov (United States)

    Vantieghem, S.; Cebron, D.; Herreman, W.; Lacaze, L.

    2013-12-01

    Models of internal planetary fluid layers (core flows, subsurface oceans) commonly assume that these fluid envelopes have a spherical shape. This approximation however entails a serious restriction from the fluid dynamics point of view. Indeed, in the presence of mechanical forcings (precession, libration, nutation or tides) due to gravitational interaction with orbiting partners, boundary topography (e.g. of the core-mantle boundary) may excite flow instabilities and space-filling turbulence. These phenomena may affect heat transport and dissipation at the main order. Here, we focus on instabilities driven by longitudinal libration. Using a suite of theoretical tools and numerical simulations, we are able to discern a parameter range for which instability may be excited. We thereby consider deformations of different azimuthal order. This study gives the first numerical evidence of the tripolar instability. Furthermore, we explore the non-linear regime and investigate the amplitude as well as the dissipation of the saturated instability. Indeed, these two quantities control the torques on the solid layers and the thermal transport. Furthermore, based on this results, we address the issue of magnetic field generation associated with these flows (by induction or by dynamo process). This instability mechanism applies to both synchronized as non-synchronized bodies. As such, our results show that a tripolar instability might be present in various terrestrial bodies (Early Moon, Gallilean moons, asteroids, etc.), where it could participate in dynamo action. Simulation of a libration-driven tripolar instability in a deformed spherical fluid layer: snapshot of the velocity magnitude, where a complex 3D flow pattern is established.

  14. Noble gases in meteorites and terrestrial planets

    Science.gov (United States)

    Wacker, J. F.

    1985-01-01

    Terrestrial planets and chondrites have noble gas platforms that are sufficiently alike, especially Ne/Ar, that they may have acquired their noble gases by similar processes. Meteorites presumably obtained their noble gases during formation in the solar nebula. Adsorption onto C - the major gas carrier in chondrites - is the likely mechanism for trapping noble gases; recent laboratory simulations support this hypothesis. The story is more complex for planets. An attractive possibility is that the planets acquired their noble gases in a late accreting veneer of chondritic material. In chondrites, noble gases correlate with C, N, H, and volatile metals; by Occam's Razor, we would expect a similar coupling in planets. Indeed, the Earth's crust and mantle contain chondritic like trace volatiles and PL group metals, respectively and the Earth's oceans resemble C chondrites in their enrichment of D (8X vs 8-10X of the galactic D/H ratio). Models have been proposed to explain some of the specific noble gas patterns in planets. These include: (1) noble gases may have been directly trapped by preplanetary material instead of arriving in a veneer; (2) for Venus, irradiation of preplanetary material, followed by diffusive loss of Ne, could explain the high concentration of AR-36; (3) the Earth and Venus may have initially had similar abundances of noble gases, but the Earth lost its share during the Moon forming event; (4) noble gases could have been captured by planetestimals, possibly leading to gravitational fractionation, particularly of Xe isotopes and (5) noble gases may have been dissolved in the hot outer portion of the Earth during contact with a primordial atmosphere.

  15. Terrestrial and aquatic mammals of the Pantanal.

    Science.gov (United States)

    Alho, C J R; Camargo, G; Fischer, E

    2011-04-01

    Different works have registered the number of mammal species within the natural habitats of the Pantanal based on currently known records, with species richness ranging from 89 to 152 of annotated occurrences. Our present list sums 174 species. However, at least three factors have to be emphasised to deal with recorded numbers: 1) to establish the ecotone limit between the floodplain (which is the Pantanal) and its neighbouring domain like the Cerrado, besides the existence of maps recently produced; 2) the lack of intensive surveys, especially on small mammals, rodents and marsupials; and 3) the constant taxonomic revision on bats, rodents and marsupials. Some species are very abundant--for example the capybara Hydrochoerus hydrochaeris and the crab-eating fox Cerdocyon thous, and some are rare, and others are still intrinsically rare--for example, the bush dog Speothos venaticus. Abundance of species is assumed to reflect ecological resources of the habitat. Local diversity and number of individuals of wild rodents and marsupials also rely on the offering of ecological resources and behavioural specialisation to microhabitat components. A large number of species interact with the type of the vegetation of the habitat, by means of habitat selection through active patterns of ecological behaviour, resulting on dependency on arboreal and forested habitats of the Pantanal. In addition, mammals respond to seasonal shrinking-and-expansion of habitats due to flooding regime of the Pantanal. The highest number of species is observed during the dry season, when there is a considerable expansion of terrestrial habitats, mainly seasonally flooded grassland. Major threats to mammal species are the loss and alteration of habitats due to human intervention, mainly deforestation, unsustainable agricultural and cattle-ranching practices, which convert the natural vegetation into pastures. The Pantanal still harbours about a dozen of species officially listened as in danger.

  16. Tidal Heating in Multilayered Terrestrial Exoplanets

    Science.gov (United States)

    Henning, Wade G.; Hurford, Terry

    2014-01-01

    The internal pattern and overall magnitude of tidal heating for spin-synchronous terrestrial exoplanets from 1 to 2.5 R(sub E) is investigated using a propagator matrix method for a variety of layer structures. Particular attention is paid to ice-silicate hybrid super-Earths, where a significant ice mantle is modeled to rest atop an iron-silicate core, and may or may not contain a liquid water ocean. We find multilayer modeling often increases tidal dissipation relative to a homogeneous model, across multiple orbital periods, due to the ability to include smaller volume low viscosity regions, and the added flexure allowed by liquid layers. Gradations in parameters with depth are explored, such as allowed by the Preliminary Earth Reference Model. For ice-silicate hybrid worlds, dramatically greater dissipation is possible beyond the case of a silicate mantle only, allowing non-negligible tidal activity to extend to greater orbital periods than previously predicted. Surface patterns of tidal heating are found to potentially be useful for distinguishing internal structure. The influence of ice mantle depth and water ocean size and position are shown for a range of forcing frequencies. Rates of orbital circularization are found to be 10-100 times faster than standard predictions for Earth-analog planets when interiors are moderately warmer than the modern Earth, as well as for a diverse range of ice-silicate hybrid super-Earths. Circularization rates are shown to be significantly longer for planets with layers equivalent to an ocean-free modern Earth, as well as for planets with high fractions of either ice or silicate melting.

  17. Tidal heating in multilayered terrestrial exoplanets

    Energy Technology Data Exchange (ETDEWEB)

    Henning, Wade G.; Hurford, Terry, E-mail: wade.g.henning@nasa.gov [NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)

    2014-07-01

    The internal pattern and overall magnitude of tidal heating for spin-synchronous terrestrial exoplanets from 1 to 2.5 R{sub E} is investigated using a propagator matrix method for a variety of layer structures. Particular attention is paid to ice-silicate hybrid super-Earths, where a significant ice mantle is modeled to rest atop an iron-silicate core, and may or may not contain a liquid water ocean. We find multilayer modeling often increases tidal dissipation relative to a homogeneous model, across multiple orbital periods, due to the ability to include smaller volume low viscosity regions, and the added flexure allowed by liquid layers. Gradations in parameters with depth are explored, such as allowed by the Preliminary Earth Reference Model. For ice-silicate hybrid worlds, dramatically greater dissipation is possible beyond the case of a silicate mantle only, allowing non-negligible tidal activity to extend to greater orbital periods than previously predicted. Surface patterns of tidal heating are found to potentially be useful for distinguishing internal structure. The influence of ice mantle depth and water ocean size and position are shown for a range of forcing frequencies. Rates of orbital circularization are found to be 10-100 times faster than standard predictions for Earth-analog planets when interiors are moderately warmer than the modern Earth, as well as for a diverse range of ice-silicate hybrid super-Earths. Circularization rates are shown to be significantly longer for planets with layers equivalent to an ocean-free modern Earth, as well as for planets with high fractions of either ice or silicate melting.

  18. NACP Site: Terrestrial Biosphere Model Output Data in Original Format

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains the original model output data submissions from the 24 terrestrial biosphere models (TBM) that participated in the North American Carbon...

  19. NACP Site: Terrestrial Biosphere Model Output Data in Original Format

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set contains the original model output data submissions from the 24 terrestrial biosphere models (TBM) that participated in the North American...

  20. Terrestrial Planet Finder Coronagraph High Accuracy Optical Propagation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Terrestrial Planet Finder (TPF) project is considering several approaches to discovering planets orbiting stars far from earth and assessing their suitability to...

  1. Maryland ESI: T_MAMMAL (Terrestrial Mammal Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for river otters in Maryland. Vector polygons in this data set represent the terrestrial mammal...

  2. Western Alaska ESI: T_MAMMAL (Terrestrial Mammal Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for brown bears in Western Alaska. Vector polygons in this data set represent terrestrial mammal...

  3. Traceable radiometry underpinning terrestrial- and helio-studies (TRUTHS)

    NARCIS (Netherlands)

    Fox, N.; Aiken, J.; Barnett, J.J.; Briottet, X.; Carvell, R.; Frohlich, C.; Groom, S.B.; Hagolle, O.; Haigh, J.D.; Kieffer, H.H.; Lean, J.; Pollock, D.B.; Quinn, T.; Sandford, M.C.W.; Schaepman, M.E.; Shine, K.P.; Schmutz, W.K.; Teillet, P.M.; Thome, K.J.; Verstraete, M.M.; Zalewski, E.

    2003-01-01

    The Traceable Radiometry Underpinning Terrestrial- and Helio- Studies (TRUTHS) mission offers a novel approach to the provision of key scientific data with unprecedented radiometric accuracy for Earth Observation (EO) and solar studies, which will also establish well-calibrated reference

  4. Virginia ESI: T_MAMMAL (Terrestrial Mammal Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for the northern river otter in Virginia. Vector polygons in this data set represent terrestrial mammal...

  5. Electrochemical Power Plant for Terrestrial Flight Platforms Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An electrochemical power plant is proposed by MicroCell Technologies to provide power to terrestrial flight platforms. Our power plant is based upon a proton...

  6. Mixotrophy in the terrestrial green alga Apatococcus lobatus (Trebouxiophyceae, Chlorophyta).

    Science.gov (United States)

    Gustavs, Lydia; Schumann, Rhena; Karsten, Ulf; Lorenz, Maike

    2016-04-01

    The green microalga Apatococcus lobatus is widely distributed in terrestrial habitats throughout many climatic zones. It dominates green biofilms on natural and artificial substrata in temperate latitudes and is regarded as a key genus of obligate terrestrial consortia. Until now, its isolation, cultivation and application as a terrestrial model organism has been hampered by slow growth rates and low growth capacities. A mixotrophic culturing approach clearly enhanced the accumulation of biomass, thereby permitting the future application of A. lobatus in different types of bio-assays necessary for material and biofilm research. The ability of A. lobatus to grow mixotrophically is assumed as a competitive advantage in terrestrial habitats. © 2015 Phycological Society of America.

  7. The Delivery of Water During Terrestrial Planet Formation

    Science.gov (United States)

    O'Brien, David P.; Izidoro, Andre; Jacobson, Seth A.; Raymond, Sean N.; Rubie, David C.

    2018-02-01

    The planetary building blocks that formed in the terrestrial planet region were likely very dry, yet water is comparatively abundant on Earth. Here we review the various mechanisms proposed for the origin of water on the terrestrial planets. Various in-situ mechanisms have been suggested, which allow for the incorporation of water into the local planetesimals in the terrestrial planet region or into the planets themselves from local sources, although all of those mechanisms have difficulties. Comets have also been proposed as a source, although there may be problems fitting isotopic constraints, and the delivery efficiency is very low, such that it may be difficult to deliver even a single Earth ocean of water this way. The most promising route for water delivery is the accretion of material from beyond the snow line, similar to carbonaceous chondrites, that is scattered into the terrestrial planet region as the planets are growing. Two main scenarios are discussed in detail. First is the classical scenario in which the giant planets begin roughly in their final locations and the disk of planetesimals and embryos in the terrestrial planet region extends all the way into the outer asteroid belt region. Second is the Grand Tack scenario, where early inward and outward migration of the giant planets implants material from beyond the snow line into the asteroid belt and terrestrial planet region, where it can be accreted by the growing planets. Sufficient water is delivered to the terrestrial planets in both scenarios. While the Grand Tack scenario provides a better fit to most constraints, namely the small mass of Mars, planets may form too fast in the nominal case discussed here. This discrepancy may be reduced as a wider range of initial conditions is explored. Finally, we discuss several more recent models that may have important implications for water delivery to the terrestrial planets.

  8. Terrestrial reptiles from San Lorenzo Island, Lima, Peru

    Directory of Open Access Journals (Sweden)

    José Pérez Z.

    2015-04-01

    Full Text Available We report four species of terrestrial reptiles, a geckonid (Phyllodactlus cf. microphyllus, two lizards (Microlophus peruvianus and M. tigris and one snake (Pseudalsophis elegans from San Lorenzo island, Departament of Lima, Peru. Herein, we report the first record of “Loma’s lizard” M. tigris and the snake P. elegans in Peruvian islands. The presence of Lomas herbaceous and the considerable extent of San Lorenzo island can explain the relatively high species richness of terrestrial reptiles on the island.

  9. PHARMACOLOGICAL SCIENTIFIC EVIDENCE FOR THE PROMISE OF TRIBULUS TERRESTRIS

    OpenAIRE

    Jameel Mohd; Ansari Javed Akhtar; Ali Abuzer; Ahamad Javed; Ali M; Tamboli Ennus

    2012-01-01

    The usage of plants, plant extracts or plant-derived pure chemicals for disease management, become a therapeutic modality, which has stood the test of time. In the present review, we focus on pharmacological profile (in tabular form) of Tribulus terrestris L., apart from Phytochemistry, Taxonomy and Traditional uses. Data were located, selected and extracted from SCI database, Medline, Pubmed, Highwire and Google Scholar. Fruits and seeds of Tribulus terrestris L., (Zygophyllaceae) are of imm...

  10. Shell bone histology indicates terrestrial palaeoecology of basal turtles

    OpenAIRE

    Scheyer, Torsten; Sander, P. Martin

    2009-01-01

    The palaeoecology of basal turtles from the Late Triassic was classically viewed as being semi-aquatic, similar to the lifestyle of modern snapping turtles. Lately, this view was questioned based on limb bone proportions, and a terrestrial palaeoecology was suggested for the turtle stem. Here, we present independent shell bone microstructural evidence for a terrestrial habitat of the oldest and basal most well-known turtles, i.e. the Upper Triassic Proterochersis robusta and Proganochelys que...

  11. Microplastics as an emerging threat to terrestrial ecosystems.

    Science.gov (United States)

    de Souza Machado, Anderson Abel; Kloas, Werner; Zarfl, Christiane; Hempel, Stefan; Rillig, Matthias C

    2017-12-15

    Microplastics (plastics microplastics might first interact with biota eliciting ecologically relevant impacts. This article introduces the pervasive microplastic contamination as a potential agent of global change in terrestrial systems, highlights the physical and chemical nature of the respective observed effects, and discusses the broad toxicity of nanoplastics derived from plastic breakdown. Making relevant links to the fate of microplastics in aquatic continental systems, we here present new insights into the mechanisms of impacts on terrestrial geochemistry, the biophysical environment, and ecotoxicology. Broad changes in continental environments are possible even in particle-rich habitats such as soils. Furthermore, there is a growing body of evidence indicating that microplastics interact with terrestrial organisms that mediate essential ecosystem services and functions, such as soil dwelling invertebrates, terrestrial fungi, and plant-pollinators. Therefore, research is needed to clarify the terrestrial fate and effects of microplastics. We suggest that due to the widespread presence, environmental persistence, and various interactions with continental biota, microplastic pollution might represent an emerging global change threat to terrestrial ecosystems. © 2017 John Wiley & Sons Ltd.

  12. Planetary Protection: Two Relevant Terrestrial Examples

    Science.gov (United States)

    Chyba, C.

    2002-09-01

    Concerns about potential pathogens in returned samples from Mars ("Mars Sample Return: Issues and Recommendations", National Research Council, 1997) or planetary satellites ("Evaluating the Biological Potential in Samples Returned from Planetary Satellites and Small Solar System Bodies", National Research Council, 1998) focus on two potential types of pathogenesis, toxic and infectious. The National Research Council reports cited above state that the chances of extraterrestrial organisms proving either toxic or infectious to humans are extremely low, but cannot be entirely ruled out. Here I discuss recently discovered terrestrial examples relevant to each possibility, in order to make these concerns concrete. The first example concerns the production of hepatotoxins (toxins affecting the liver) and neurotoxins by cyanobacteria in glacial lakes on alpine pastures in Switzerland. In this example, mat-forming benthic cyanobacteria are implicated in a hundred cattle poisonings that have been reported from alpine pasteurs in southeastern Switzerland over the past twenty-five years (e.g. K. Mez et al, Hydrobiologia 368, 1-15 (1998)). It is unlikely that these cyanobacteria evolved the toxins in response to dairy cows; rather the susceptibility of cattle to these toxins seems simply to be an unfortunate coincidence of a toxin working across a large evolutionary distance. The second example concerns the recent demonstration that the decimation of shallow-water Caribbean elkhorn coral is due to infection by a common fecal enterobacterium associated with the human gut (K. L. Patterson et al., PNAS 99, 8725-8730 (2002)). The bacterium, Serratia marcenscens, is also a free-living microbe in water and soil, as well as an opportunistic pathogen in a variety of animal species. The distance between humans and corals emphasizes the possibility that certain organisms may prove pathogenic across a wide evolutionary divide. Of course, in neither of these cases are the evolutionary

  13. Geochemical Evidence for a Terrestrial Magma Ocean

    Science.gov (United States)

    Agee, Carl B.

    1999-01-01

    The aftermath of phase separation and crystal-liquid fractionation in a magma ocean should leave a planet geochemically differentiated. Subsequent convective and other mixing processes may operate over time to obscure geochemical evidence of magma ocean differentiation. On the other hand, core formation is probably the most permanent, irreversible part of planetary differentiation. Hence the geochemical traces of core separation should be the most distinct remnants left behind in the mantle and crust, In the case of the Earth, core formation apparently coincided with a magma ocean that extended to a depth of approximately 1000 km. Evidence for this is found in high pressure element partitioning behavior of Ni and Co between liquid silicate and liquid iron alloy, and with the Ni-Co ratio and the abundance of Ni and Co in the Earth's upper mantle. A terrestrial magma ocean with a depth of 1000 km will solidify from the bottom up and first crystallize in the perovskite stability field. The largest effect of perovskite fractionation on major element distribution is to decrease the Si-Mg ratio in the silicate liquid and increase the Si-Mg ratio in the crystalline cumulate. Therefore, if a magma ocean with perovskite fractionation existed, then one could expect to observe an upper mantle with a lower than chondritic Si-Mg ratio. This is indeed observed in modern upper mantle peridotites. Although more experimental work is needed to fully understand the high-pressure behavior of trace element partitioning, it is likely that Hf is more compatible than Lu in perovskite-silicate liquid pairs. Thus, perovskite fractionation produces a molten mantle with a higher than chondritic Lu-Hf ratio. Arndt and Blichert-Toft measured Hf isotope compositions of Barberton komatiites that seem to require a source region with a long-lived, high Lu-Hf ratio. It is plausible that that these Barberton komatiites were generated within the majorite stability field by remelting a perovskite

  14. Can Terrestrial Microbes Grow on Mars?

    Science.gov (United States)

    Rothschild, Lynn

    2012-01-01

    The theme for AbSciCon 2012 is "Exploring Life: Past and Present, Near and Far." The conference will address our current understanding of life - from processes at the molecular level to those which operate at planetary scales. Studying these aspects of life on Earth provides an essential platform from which to examine the potential for life on other worlds, both within our solar system and beyond. Mars exhibits a variety of extreme environments characterized by high UV and ionizing radiation flux, low pressure anoxic atmosphere, scarce or absent liquid water, extreme low temperatures, etc. The ability of terrestrial microorganisms to survive and adapt to the Mars environment has profound implications for astrobiology, planetary protection, and Mars life detection missions. At the NASA Ames Synthetic Biology Initiative, we believe that synthetic biology has the potential to revolutionize human space exploration. As such, the initiative is dedicated to applying the tools and techniques of synthetic biology to space exploration and astrobiology. Biological solutions will be invaluable for space exploration because they are not resource intensive, and they are versatile and self-renewing. An understanding of how to work with DNA in an unfavorable environment is paramount to utilizing biological tools on space missions. Furthermore, the ability to adjust life to the parameters of Mars is vital both to discovering what life on Mars might look like, and to using biological tools under such conditions. As a first step, we need an energy-efficient, low cost means of transporting, storing, and protecting genomic DNA, DNA parts, and whole microbial strains. Our goal is to develop and demonstrate viable and superior alternatives to standard DNA storage methods, which can be optimized to the conditions of space exploration, using synthetic biology as a tool. This includes protocols and kit designs for easy and repeatable DNA and strain recovery from protective storage

  15. Terrestrial feeding in aquatic turtles: environment-dependent feeding behavior modulation and the evolution of terrestrial feeding in Emydidae.

    Science.gov (United States)

    Stayton, Charles Tristan

    2011-12-15

    Evolutionary transitions between aquatic and terrestrial environments are common in vertebrate evolution. These transitions require major changes in most physiological functions, including feeding. Emydid turtles are ancestrally aquatic, with most species naturally feeding only in water, but some terrestrial species can modulate their feeding behavior appropriately for both media. In addition, many aquatic species can be induced to feed terrestrially. A comparison of feeding in both aquatic and terrestrial environments presents an excellent opportunity to investigate the evolution of terrestrial feeding from aquatic feeding, as well as a system within which to develop methods for studying major evolutionary transitions between environments. Individuals from eight species of emydid turtles (six aquatic, two terrestrial) were filmed while feeding underwater and on land. Bite kinematics were analyzed to determine whether aquatic turtles modulated their feeding behavior in a consistent and appropriate manner between environments. Aquatic turtles showed consistent changes between environments, taking longer bites and using more extensive motions of the jaw and hyoid when feeding on land. However, these motions differ from those shown by species that naturally feed in both environments and mostly do not seem to be appropriate for terrestrial feeding. For example, more extensive motions of the hyoid are only effective during underwater suction feeding. Emydids evolving to feed on land probably would have needed to evolve or learn to overcome many, but not all, aspects of the intrinsic emydid response to terrestrial feeding. Studies that investigate major evolutionary transitions must determine what responses to the new environment are shown by naïve individuals in order to fully understand the evolutionary patterns and processes associated with these transitions.

  16. Some effects of pollutants in terrestrial ecosystems

    Science.gov (United States)

    Stickel, W.H.; McIntyre, A.D.; Mills, C.F.

    1975-01-01

    occur when persistent chemicals enter organisms that eliminate them poorly. However, loss of chemicals in the food chain must be more common than accumulation. The great concentration from water to aquatic organism is chiefly a physical phenomenon, not a food chain effect, but it affords high starting levels for these chains. Terrestrial food chains often start at a high level with heavily contaminated, struggling prey. Litter feeders are another important base. Vegetation may be contaminated enough to be dangerous to animals that eat it. Dermal and respiratory routes of intoxication occur in the wild, but the oral route is far more important at most times and places. The organisms that govern soil fertility and texture are affected more by cultivation than by pesticides. Above ground, growing knowledge of resistance, species differences, and biological controls is leading to integrated control, in which use of chemicals is limited and specific. We do not know what is happening to most nontarget invertebrates. Amphibians and reptiles may be killed by applications of insecticides, but are not highly sensitive and can carry large residues. Effects of these residues on reproduction are little known. Heavy kills of birds by pesticides still occur in the field. Fish-eating and bird-eating birds also undergo shell thinning and related reproductive troubles in many areas, sometimes to the point of population decline and local or regional extermination. DDE most often correlates with shell thinning in the wild and in experiments. No other known chemical approaches DDE in causing severe and lasting shell thinning. Herbivorous birds seem to be largely immune to this effect. It is uncertain how much dieldrin and PCBs contribute to embryotoxicity in carnivorous birds. Mammals may be killed by the more toxic pesticides, but some of the commonest small rodents are so resistant, and lose their residues so rapidly, that they are of little

  17. NEON Airborne Remote Sensing of Terrestrial Ecosystems

    Science.gov (United States)

    Kampe, T. U.; Leisso, N.; Krause, K.; Karpowicz, B. M.

    2012-12-01

    The National Ecological Observatory Network (NEON) is the continental-scale research platform that will collect information on ecosystems across the United States to advance our understanding and ability to forecast environmental change at the continental scale. One of NEON's observing systems, the Airborne Observation Platform (AOP), will fly an instrument suite consisting of a high-fidelity visible-to-shortwave infrared imaging spectrometer, a full waveform small footprint LiDAR, and a high-resolution digital camera on a low-altitude aircraft platform. NEON AOP is focused on acquiring data on several terrestrial Essential Climate Variables including bioclimate, biodiversity, biogeochemistry, and land use products. These variables are collected throughout a network of 60 sites across the Continental United States, Alaska, Hawaii and Puerto Rico via ground-based and airborne measurements. Airborne remote sensing plays a critical role by providing measurements at the scale of individual shrubs and larger plants over hundreds of square kilometers. The NEON AOP plays the role of bridging the spatial scales from that of individual organisms and stands to the scale of satellite-based remote sensing. NEON is building 3 airborne systems to facilitate the routine coverage of NEON sites and provide the capacity to respond to investigator requests for specific projects. The first NEON imaging spectrometer, a next-generation VSWIR instrument, was recently delivered to NEON by JPL. This instrument has been integrated with a small-footprint waveform LiDAR on the first NEON airborne platform (AOP-1). A series of AOP-1 test flights were conducted during the first year of NEON's construction phase. The goal of these flights was to test out instrument functionality and performance, exercise remote sensing collection protocols, and provide provisional data for algorithm and data product validation. These test flights focused the following questions: What is the optimal remote

  18. Snowmelt monitoring with Terrestrial Laser Scanner Measurements

    Science.gov (United States)

    Anttila, Kati; Kaasalainen, Sanna; Kaartinen, Harri; Krooks, Anssi; Manninen, Terhikki; Lahtinen, Panu; Riihelä, Aku; Siljamo, Niilo; Thölix, Laura; Karjalainen, Tuure

    2010-05-01

    The increasing use of satellite data has caused an increasing need for validation data. Terrestrial laser scanning (TLS) and Mobile Mapping Systems (MMS) are potential methods of gaining information on vast areas at remote locations. We have investigated the snowmelt 2009 using stationary and mobile TLS during the SNORTEX -campaign (Snow Reflectance Transition Experiment) in several locations in Finnish Lapland during 2008-2009. The SNORTEX is a 3-years investigation (started in 2008) piloted by Météo-France and FMI (Finnish Meteorological Institute). The key objectives of SNORTEX are to improve the characterization of snow-melting patterns in boreal regions using a multiscale approach supported by multi-angular and multi-spectral remote sensing information, and to build an integrated database for snow variables (albedo, fraction, water equivalent) in a forested environment for the validation of the SAF (Satellite Application Facilities) snow-related products. Validation data for EUMETSAT Land, Climate and Hydrological SAFs will be gathered in the campaign. The focus of the 2009 campaign was on the melting season. The field work was scheduled to include different snow/weather conditions and to include a time period with fractional snow cover. There will be one more field measurement period in spring 2010. The field survey took place at Sodankylä in Finnish Lapland. The existing facilities of FMI-ARC (The Arctic Research Center of the Finnish Meteorological Institutes) (67.4 °N 26.6 °E) were used. The studied area was chosen for this campaign because it is located far from the coasts, which makes the climate continental. The winters are long and cold during which the snow usually does not completely melt and several layers form in the snow pack. The area is partially forested which makes it possible to observe how the forests affect snow, snow cover and albedo. In addition to this the topography of the area is relatively plain which makes the area ideal for

  19. A Unified Model for Slug Flow Generation Modélisation de la formation des bouchons : vers un modèle stochastique unifié

    Directory of Open Access Journals (Sweden)

    Bernicot M.

    2006-11-01

    Full Text Available In order to improve the global safety and reliability level of multi-phase production systems and to guarantee their economical efficiency, we need a better understanding and control of hydraulic instabilities observed at the outlet of multi-phase sea-lines. This may be obtained through the development of slug flow stochastic models, which must be able to explain:(a The generation of the various types of slug length distributions which are observed on experimental data sets. (b The evolution of these distributions along the sea-lines up to their outlets, where large hydraulic fluctuations may be dangerous for the treatment installations. Based on experimental as well as theoretical arguments, we present such a model with emphasis on slug generation. We give a detailed theoretical analysis, together with a discussion of the underlying assumptions which justify the introduction of this model. Ce résumé contient des formules (*** qui ne peuvent s'afficher à l'écran. Pour garantir à la fois la sûreté de fonctionnement et la rentabilité des systèmes de production avec transport polyphasique, il est nécessaire de mieux comprendre et maîtriser les phénomènes d'instabilité hydraulique dans les conduites polyphasiques. Ceci suppose la mise au point et l'utilisation de Modèles de Simulation des écoulements portant, non seulement sur l'évolution dans le temps et en tout point de la conduite des valeurs moyennes des diverses variables (cf. le modèle TACITE, mais aussi sur leurs aspects stochastiques en prenant spécialement en compte : - les lois statistiques propres des divers mécanismes fondamentaux de formation des bouchons (distribution des longueurs de bouchons de liquide et de poches de gaz; - l'évolution de ces lois statistiques dans le temps et tout le long de la conduite (et ceci, jusqu'à son extrémité, extrémité dont les caractéristiques intéressent tout spécialement l'opérateur de la conduite. Nous présenterons ici

  20. Comparison of Jovian and Terrestrial Lightning as Observed from Space

    Science.gov (United States)

    Dyudina, Ulyana A.; Ingersoll, A. P.; Boccippio, Dennis; Arnold, James E. (Technical Monitor)

    2001-01-01

    We compare the images of Jovian lightning taken by Galileo spacecraft with the images of terrestrial lightning observed by Lightning Imaging Spectrometer (LIS) onboard the TERRA spacecraft. Both data sets have good spatial resolution: Galileo's pixel is 25 km, or about half the atmospheric scale height, LIS pixel is 3-6 km, also about half of the scale height. This good resolution allows us to see that both Jovian and terrestrial lightning spots look diffuse because of the scattering in the clouds above. Previously we used the appearance of the diffuse spots on Jupiter to model lightning depths and the opacity and shape of the overlying clouds (Dyudina and Ingersoll, 2000). The comparison with LIS data allowed us to verify that the model is valid for terrestrial lightning. The irregular shapes of large terrestrial lightning suggests 30-km scale horizontal bolts. On Jupiter the spots, projected onto the horizontal plane, are nearly circular suggesting that the large size of the spots is mostly due to the horizontal diffusion of the photons scattered in the clouds. Unlike the Galileo observations, LIS has fine temporal resolution of 2 ms, or about 250 frames per single lightning flash. We will discuss the temporal evolution of terrestrial flashes and its implications for Jupiter.

  1. Water vapor estimation using digital terrestrial broadcasting waves

    Science.gov (United States)

    Kawamura, S.; Ohta, H.; Hanado, H.; Yamamoto, M. K.; Shiga, N.; Kido, K.; Yasuda, S.; Goto, T.; Ichikawa, R.; Amagai, J.; Imamura, K.; Fujieda, M.; Iwai, H.; Sugitani, S.; Iguchi, T.

    2017-03-01

    A method of estimating water vapor (propagation delay due to water vapor) using digital terrestrial broadcasting waves is proposed. Our target is to improve the accuracy of numerical weather forecast for severe weather phenomena such as localized heavy rainstorms in urban areas through data assimilation. In this method, we estimate water vapor near a ground surface from the propagation delay of digital terrestrial broadcasting waves. A real-time delay measurement system with a software-defined radio technique is developed and tested. The data obtained using digital terrestrial broadcasting waves show good agreement with those obtained by ground-based meteorological observation. The main features of this observation are, no need for transmitters (receiving only), applicable wherever digital terrestrial broadcasting is available and its high time resolution. This study shows a possibility to estimate water vapor using digital terrestrial broadcasting waves. In the future, we will investigate the impact of these data toward numerical weather forecast through data assimilation. Developing a system that monitors water vapor near the ground surface with time and space resolutions of 30 s and several kilometers would improve the accuracy of the numerical weather forecast of localized severe weather phenomena.

  2. Terrestrial microbes in martian and chondritic meteorites

    Science.gov (United States)

    Airieau, S.; Picenco, Y.; Andersen, G.

    2007-08-01

    Introduction: The best extraterrestrial analogs for microbiology are meteorites. The chemistry and mineralogy of Asteroid Belt and martian (SNC) meteorites are used as tracers of processes that took place in the early solar system. Meteoritic falls, in particular those of carbonaceous chondrites, are regarded as pristine samples of planetesimal evolution as these rocks are primitive and mostly unprocessed since the formation of the solar system 4.56 billion years ago. Yet, questions about terrestrial contamination and its effects on the meteoritic isotopic, chemical and mineral characteristics often arise. Meteorites are hosts to biological activity as soon as they are in contact with the terrestrial biosphere, like all rocks. A wide biodiversity was found in 21 chondrites and 8 martian stones, and was investigated with cell culture, microscopy techniques, PCR, and LAL photoluminetry. Some preliminary results are presented here. The sample suite included carbonaceous chondrites of types CR, CV, CK, CO, CI, and CM, from ANSMET and Falls. Past studies documented the alteration of meteorites by weathering and biological activity [1]-[4]. Unpublished observations during aqueous extraction for oxygen isotopic analysis [5], noted the formation of biofilms in water in a matter of days. In order to address the potential modification of meteoritic isotopic and chemical signatures, the culture of microbial contaminating species was initiated in 2005, and after a prolonged incubation, some of the species obtained from cell culture were analyzed in 2006. The results are preliminary, and a systematic catalog of microbial contaminants is developing very slowly due to lack of funding. Methods: The primary method was cell culture and PCR. Chondrites. Chondritic meteorite fragments were obtained by breaking stones of approximately one gram in sterile mortars. The core of the rocks, presumably less contaminated than the surface, was used for the present microbial study, and the

  3. Observing terrestrial ecosystems and the carbon cycle from space

    Energy Technology Data Exchange (ETDEWEB)

    Schimel, David [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91101 USA; Pavlick, Ryan [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91101 USA; Fisher, Joshua B. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91101 USA; Asner, Gregory P. [Department of Global Ecology, Carnegie Institution for Science, 260 Panama St. Stanford CA 94305 USA; Saatchi, Sassan [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91101 USA; Townsend, Philip [University of Wisconsin-Madison, Madison WI 53706 USA; Miller, Charles [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91101 USA; Frankenberg, Christian [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91101 USA; Hibbard, Kathy [Pacific Northwest National Laboratory, PO Box 999 MSIN: K9-34 Richland WA 99352 USA; Cox, Peter [College of Engineering, Mathematics and Physical Sciences, University of Exeter, North Park Road Streatham Campus Harrison Building Exeter EX4 4QF UK

    2015-02-06

    Modeled terrestrial ecosystem and carbon cycle feedbacks contribute substantial uncertainty to projections of future climate. The limitations of current observing networks contribute to this uncertainty. Here we present a current climatology of global model predictions and observations for photosynthesis, biomass, plant diversity and plant functional diversity. Carbon cycle tipping points occur in terrestrial regions where fluxes or stocks are largest, and where biological variability is highest, the tropics and Arctic/Boreal zones. Global observations are predominately in the mid-latitudes and are sparse in high and low latitude ecosystems. Observing and forecasting ecosystem change requires sustained observations of sufficient density in time and space in critical regions. Using data and theory available now, we can develop a strategy to detect and forecast terrestrial carbon cycle-climate interactions, by combining in situ and remote techniques.

  4. From terrestrial to aquatic habitats and back again

    DEFF Research Database (Denmark)

    Ito, Yu; Tanaka, Norio; Barfod, Anders S.

    2017-01-01

    for ancestral state reconstruction and biogeographic inference. We obtained moderately resolved phylogenetic trees, showing that two terrestrial species, one from Australasia and the other from temperate and tropical Asia, are the first diverging species and the remaining terrestrial species are scattered...... terrestrial habitats is yet to be addressed. The origin of its cosmopolitan distribution, especially to or from Australasia, remains uncertain. We assessed evolution of growth habit and inferred biogeographic history in a phylogenetic framework using DNA sequence data from plastid DNA and the nuclear internal...... transcribed spacer region. These were separately analysed using maximum parsimony, maximum likelihood and Bayesian inference. The multilocus data sets, excluding two species exhibiting conflicting placement, were then used for coalescent-based species-tree analysis and the resulting species tree was used...

  5. Microalgal and Terrestrial Transport Biofuels to Displace Fossil Fuels

    Directory of Open Access Journals (Sweden)

    Lucas Reijnders

    2009-02-01

    Full Text Available Terrestrial transport biofuels differ in their ability to replace fossil fuels. When both the conversion of solar energy into biomass and the life cycle inputs of fossil fuels are considered, ethanol from sugarcane and biodiesel from palm oil do relatively well, if compared with ethanol from corn, sugar beet or wheat and biodiesel from rapeseed. When terrestrial biofuels are to replace mineral oil-derived transport fuels, large areas of good agricultural land are needed: about 5x108 ha in the case of biofuels from sugarcane or oil palm, and at least 1.8-3.6x109 ha in the case of ethanol from wheat, corn or sugar beet, as produced in industrialized countries. Biofuels from microalgae which are commercially produced with current technologies do not appear to outperform terrestrial plants such as sugarcane in their ability to displace fossil fuels. Whether they will able to do so on a commercial scale in the future, is uncertain.

  6. Production rates of terrestrial in-situ-produced cosmogenic nuclides

    Energy Technology Data Exchange (ETDEWEB)

    Reedy, R.C. [Los Alamos National Lab., NM (United States); Tuniz, C.; Fink, D. [Australian Nuclear Science and Technology Organisation, Menai, NSW (Australia)

    1993-12-31

    Production rates of cosmogenic nuclides made in situ in terrestrial samples and how they are applied to the interpretation of measured radionuclide concentrations were discussed at a one-day Workshop held 2 October 1993 in Sydney, Australia. The status of terrestrial in-situ studies using the long-lived radionuclides {sup 10}Be, {sup 14}C, {sup 26}Al, {sup 36}Cl, and {sup 41}Ca and of various modeling and related studies were presented. The relative uncertainties in the various factors that go into the interpretation of these terrestrial in-situ cosmogenic nuclides were discussed. The magnitudes of the errors for these factors were estimated and none dominated the final uncertainty.

  7. Applications of modern digital terrestrial photogrammetry to problems in glaciology.

    Science.gov (United States)

    Pfeffer, W.

    2004-12-01

    Recent developments in digital photogrammetry allow reliable, accurate, stereometric models of detailed objects such as glaciers to be constructed at reduced cost and effort in comparison to conventional film-based aerial or terrestrial photogrammetric methods. These developments include: 1) Correction of lens distortion by digital remapping of images; 2) Digital measurement of image space coordinate measurements; 3) Ease with which multiple stereomodels may be combined, permitting redundancy and strong parallax. These improvements make stereophotogrammetry a practical and cost effective alternative to other mapping procedures (e.g. optical survey, laser profiling) for small- to medium-scale glaciology projects. The relative strengths of digital terrestrial photogrammetry are compared to traditional film-based photogrammetric procedures as well as to other ground-based and airborne survey methods and satellite imagery, and several examples of terrestrial photogrammetric applications to glaciers are presented, including topographic profiling, velocity determination, and structural mapping.

  8. Regional terrestrial ecosystem dynamics and their interactions with the atmosphere

    Science.gov (United States)

    Ojima, D.; Schimel, D.; Parton, W.; McKeown, R.

    2003-04-01

    Integration of land use with human dimensions, biological, atmospheric and hydrological processes is necessary for us to estimate net carbon exchange from the terrestrial biota. However, proper handling of scale across a set of divergent processes interconnecting the atmosphere and the biosphere is critical to the success of this analysis. Development of the new IGBP “Land” Project will develop a structure to better integrate research that has advanced during the past decade. Our understanding of the long term changes in the terrestrial biosphere will provide greater insight to the environmental sustainability under different stresses and provide an indication of how different regions may respond to changes in climate, disturbance regimes, and land use. This insight will provide a framework to better develop earth system science over the coming decade and to better incorporate the human-environmental system perspective. Our understanding of the biological controls of carbon fluxes between the atmosphere and the land surface (referring to the soil, vegetation, water system) is critical to our estimation of net terrestrial carbon fluxes and the connection of key natural resources (e.g., water, vegetation, soils, etc) to climate and land use changes. Terrestrial biological processes respond strongly to atmospheric temperature, humidity, CO2 levels, N-deposition, precipitation, and radiative transfers. The development of this integrated science perspective to understand the scope of effects human activities on land are affecting the feedbacks to the earth system and the impacts on the terrestrial human-environment system. The presentation will focus on the development of this framework and highlight recent advances in our observational and analytical components of terrestrial biosphere research.

  9. Kinematics of aquatic and terrestrial escape responses in mudskippers.

    Science.gov (United States)

    Swanson, Brook O; Gibb, Alice C

    2004-11-01

    Escape responses in fishes are rapid behaviors that are critical for survival. The barred mudskipper (Periophthalmus argentilineatus) is an amphibious fish that must avoid predators in two environments. We compared mudskipper terrestrial and aquatic escapes to address two questions. First, how does an amphibious fish perform an escape response in a terrestrial environment? Second, how similar is a terrestrial escape response to an aquatic escape response? Because a mudskipper on land does not have to contend with the high viscosity of water, we predicted that, if the same behavior is employed across environments, terrestrial escape responses should have 'better' performance (higher velocity and more rapid completion of movements) when compared with aquatic escape responses. By contrast, we predicted that intervertebral bending would be similar across environments because previous studies of escape response behaviors in fishes have proposed that vertebral morphology constrains intervertebral bending. High-speed digital imaging was used to record mudskipper escapes in water and on land, and the resulting images were used to calculate intervertebral bending during the preparatory phase, peak velocity and acceleration of the center of mass during the propulsive phase, and relative timing of movements. Although similar maximum velocities are achieved across environments, terrestrial responses are distinct from aquatic responses. During terrestrial escapes, mudskippers produce greater axial bending in the preparatory phase, but only in the posterior region of the body and over a much longer time period. Mudskippers also occasionally produced the 'wrong' behavior for a given environment. Thus, it appears that the same locomotor morphology is recruited differently by the central nervous system to produce a distinct behavior appropriate for each environment.

  10. Global change and terrestrial ecosystems: the operational plan

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, W.L.; Walker, B.H.; Ingram, J.S.I.; Koch, G.W. (eds.)

    1992-04-01

    The International Geosphere-Biosphere Programme (IGBP) has established a core project on Global Change and Terrestrial Ecosystems (GCTE). The objectives of GCTE are: to predict the effects of changes in climate, atmospheric composition, and land use on terrestrial ecosystems, including agricultural and production forest systems; and to determine how these effects lead to feedbacks to the atmosphere and the physical climate system. The research plan has four foci: ecosystem physiology, change in ecosystem structure, global change impact on agriculture and forestry; and global change and ecological complexity. The research strategy is outlined. 17 refs., 6 figs.

  11. Influence of multiple global change drivers on terrestrial carbon storage

    DEFF Research Database (Denmark)

    Yue, Kai; Fornara, Dario A; Yang, Wanqin

    2017-01-01

    The interactive effects of multiple global change drivers on terrestrial carbon (C) storage remain poorly understood. Here, we synthesise data from 633 published studies to show how the interactive effects of multiple drivers are generally additive (i.e. not differing from the sum...... of their individual effects) rather than synergistic or antagonistic. We further show that (1) elevated CO2 , warming, N addition, P addition and increased rainfall, all exerted positive individual effects on plant C pools at both single-plant and plant-community levels; (2) plant C pool responses to individual...... additive effects of multiple global change drivers into future assessments of the C storage ability of terrestrial ecosystems....

  12. Terrestrial neutron-induced soft errors in advanced memory devices

    CERN Document Server

    Nakamura, Takashi; Ibe, Eishi; Yahagi, Yasuo; Kameyama, Hideaki

    2008-01-01

    Terrestrial neutron-induced soft errors in semiconductor memory devices are currently a major concern in reliability issues. Understanding the mechanism and quantifying soft-error rates are primarily crucial for the design and quality assurance of semiconductor memory devices. This book covers the relevant up-to-date topics in terrestrial neutron-induced soft errors, and aims to provide succinct knowledge on neutron-induced soft errors to the readers by presenting several valuable and unique features. Sample Chapter(s). Chapter 1: Introduction (238 KB). Table A.30 mentioned in Appendix A.6 on

  13. The Functionally-Assembled Terrestrial Ecosystem Simulator Version 1

    Energy Technology Data Exchange (ETDEWEB)

    2017-06-02

    The Functionally-Assembled Terrestrial Ecosystem Simulator (FATES) is a vegetation model for use in Earth system models (ESMs). The model includes a size- and age-structured representation of tree dynamics, competition between functionally diverse plant functional types, and the biophysics underpinning plant growth, competition, mortality, as well as the carbon, water, and energy exchange with the atmosphere. The FATES model is designed as a modular vegetation model that can be integrated within a host land model for inclusion in ESMs. The model is designed for use in global change studies to understand and project the responses and feedbacks between terrestrial ecosystems and the Earth system under changing climate and other forcings.

  14. Theory and Realization of Global Terrestrial Reference Systems

    Science.gov (United States)

    Ma, C.; Bolotin, S.; Gipson, J.; Gordon, D.; Le Bail, K.; MacMillan, D.

    2010-01-01

    Comparison of realizations of the terrestrial reference frame. IGN and DGFI both generated realizations of the terrestrial reference frame under the auspices of the IERS from combination of the same space geodetic data. We examined both results for VLBI sites using the full geodetic VLBI data set with respect to site positions and velocities and time series of station positions, baselines and Earth orientation parameters. One of the difficulties encountered was matching episodic breaks and periods of non-linear motion of the two realizations with the VLBI models. Our analysis and conclusions will be discussed.

  15. Environmental radionuclides tracers and timers of terrestrial processes

    CERN Document Server

    Froehlich, Klaus

    2009-01-01

    The book presents a state-of-the-art summary of knowledge on the use of radionuclides to study processes and systems in the continental part of the Earth's environment. It is conceived as a companion to the two volumes of this series, which deal with isotopes as tracers in the marine environment (Livingston, Marine Radioactivity) and with the radioecology of natural and man-made terrestrial systems (Shaw, Radioactivity in Terrestrial Ecosystems). Although the book focuses on natural and anthropogenic radionuclides (radioactive isotopes), it also refers to stable environmental isotopes, which i

  16. Origin of noble gases in the terrestrial planets

    Science.gov (United States)

    Pepin, Robert O.

    1992-01-01

    Current models of the origin of noble gases in the terrestrial planets are reviewed. Primary solar system volatile sources and processes are examined along with the current data base on noble gases and its applications to evolutionary processing. Models of atmospheric evolution by hydrodynamic escape are addressed.

  17. Anti-hyperglycaemic Activity of Tribulus terrestris L Aerial Part ...

    African Journals Online (AJOL)

    Purpose: To investigate the anti-hyperglycaemic activity of methanol extract of Tribulus terrestris L. Zygophyllaceae in glucose-loaded normal rabbits. Methods: The animals were randomly assigned to 4 groups (n = 5) and treated with a single oral dose. Group 1 served as normal control group and received distilled water; ...

  18. Differences in predatory pressure on terrestrial snails by birds and ...

    Indian Academy of Sciences (India)

    The evolution of shell polymorphism in terrestrial snails is a classic textbook example of the effect of natural selection in which avian and mammalian predation represents an important selective force on gene frequency. However, many questions about predation remain unclear, especially in the case of mammals.

  19. A Google Earth Grand Tour of the Terrestrial Planets

    Science.gov (United States)

    De Paor, Declan; Coba, Filis; Burgin, Stephen

    2016-01-01

    Google Earth is a powerful instructional resource for geoscience education. We have extended the virtual globe to include all terrestrial planets. Downloadable Keyhole Markup Language (KML) files (Google Earth's scripting language) associated with this paper include lessons about Mercury, Venus, the Moon, and Mars. We created "grand…

  20. Hydrological and biogeochemical constraints on terrestrial carbon cycle feedbacks

    Science.gov (United States)

    Mystakidis, Stefanos; Seneviratne, Sonia I.; Gruber, Nicolas; Davin, Edouard L.

    2017-01-01

    The feedbacks between climate, atmospheric CO2 concentration and the terrestrial carbon cycle are a major source of uncertainty in future climate projections with Earth systems models. Here, we use observation-based estimates of the interannual variations in evapotranspiration (ET), net biome productivity (NBP), as well as the present-day sensitivity of NBP to climate variations, to constrain globally the terrestrial carbon cycle feedbacks as simulated by models that participated in the fifth phase of the coupled model intercomparison project (CMIP5). The constraints result in a ca. 40% lower response of NBP to climate change and a ca. 30% reduction in the strength of the CO2 fertilization effect relative to the unconstrained multi-model mean. While the unconstrained CMIP5 models suggest an increase in the cumulative terrestrial carbon storage (477 PgC) in response to an idealized scenario of 1%/year atmospheric CO2 increase, the constraints imply a ca. 19% smaller change. Overall, the applied emerging constraint approach offers a possibility to reduce uncertainties in the projections of the terrestrial carbon cycle, which is a key determinant of the future trajectory of atmospheric CO2 concentration and resulting climate change.

  1. Significance of terrestrial inflows to carbon and nitrogen distribution ...

    African Journals Online (AJOL)

    Significance of terrestrial inflows to carbon and nitrogen distribution in the Lake Victoria surface water. ... Samples away from the river mouth provided C:N ratios within the Redfield ratio range (C:N:P; 106:16:1) indicating materials of phytoplanktonic origin. The POM isotopes composition indicated a maximum ä13C value of ...

  2. Experimental nutrient additions accelerate terrestrial carbon loss from stream ecosystems

    Science.gov (United States)

    Amy D. Rosemond; Jonathan P. Benstead; Phillip M. Bumpers; Vladislav Gulis; John S. Kominoski; David W.P. Manning; Keller Suberkropp; J. Bruce. Wallace

    2015-01-01

    Nutrient pollution of freshwater ecosystems results in predictable increases in carbon (C) sequestration by algae. Tests of nutrient enrichment on the fates of terrestrial organic C, which supports riverine food webs and is a source of CO2, are lacking. Using whole-stream nitrogen (N) and phosphorus (P) additions spanning the equivalent of 27 years, we found that...

  3. Origin and evolution of life on terrestrial planets.

    Science.gov (United States)

    Brack, A; Horneck, G; Cockell, C S; Bérces, A; Belisheva, N K; Eiroa, Carlos; Henning, Thomas; Herbst, Tom; Kaltenegger, Lisa; Léger, Alain; Liseau, Réne; Lammer, Helmut; Selsis, Franck; Beichman, Charles; Danchi, William; Fridlund, Malcolm; Lunine, Jonathan; Paresce, Francesco; Penny, Alan; Quirrenbach, Andreas; Röttgering, Huub; Schneider, Jean; Stam, Daphne; Tinetti, Giovanna; White, Glenn J

    2010-01-01

    The ultimate goal of terrestrial planet-finding missions is not only to discover terrestrial exoplanets inside the habitable zone (HZ) of their host stars but also to address the major question as to whether life may have evolved on a habitable Earth-like exoplanet outside our Solar System. We note that the chemical evolution that finally led to the origin of life on Earth must be studied if we hope to understand the principles of how life might evolve on other terrestrial planets in the Universe. This is not just an anthropocentric point of view: the basic ingredients of terrestrial life, that is, reduced carbon-based molecules and liquid H(2)O, have very specific properties. We discuss the origin of life from the chemical evolution of its precursors to the earliest life-forms and the biological implications of the stellar radiation and energetic particle environments. Likewise, the study of the biological evolution that has generated the various life-forms on Earth provides clues toward the understanding of the interconnectedness of life with its environment.

  4. Reducing uncertainty in projections of terrestrial carbon uptake

    Science.gov (United States)

    Lovenduski, Nicole S.; Bonan, Gordon B.

    2017-04-01

    Carbon uptake by the oceans and terrestrial biosphere regulates atmospheric carbon dioxide concentration and affects Earth’s climate, yet global carbon cycle projections over the next century are highly uncertain. Here, we quantify and isolate the sources of projection uncertainty in cumulative ocean and terrestrial carbon uptake over 2006-2100 by performing an analysis of variance on output from an ensemble of 12 Earth System Models. Whereas uncertainty in projections of global ocean carbon accumulation by 2100 is 160 Pg C and driven primarily by model structure. To statistically reduce uncertainty in terrestrial carbon projections, we devise schemes to weight the models based on their ability to represent the observed change in carbon accumulation over 1959-2005. The weighting schemes incrementally reduce uncertainty to a minimum value of 125 Pg C in 2100, but this reduction requires an impractical observational constraint. We suggest that a focus on reducing multi-model spread may not make terrestrial carbon cycle projections more reliable, and instead advocate for accurate observations, improved process understanding, and a multitude of modeling approaches.

  5. Isotopic tracers for net primary productivity for a terrestrial esocystem ...

    African Journals Online (AJOL)

    Modeled estimates of heterotrophic soil respiration exceeds slightly the estimated NPP values, implying that carbon flux to and from the Volta river watershed is close to being in balance. In other words, the watershed releases annually more carbon dioxide to the atmosphere than it takes. Apart from the terrestrial carbon flux ...

  6. Climate control of terrestrial carbon exchange across biomes and continents

    DEFF Research Database (Denmark)

    Yi, Chuixiang; Ricciuto, Daniel; Li, Runze

    2010-01-01

    climate and terrestrial CO2 exchange with the atmosphere across biomes and continents are lacking. Here we present data describing the relationships between net ecosystem exchange of carbon (NEE) and climate factors as measured using the eddy covariance method at 125 unique sites in various ecosystems...

  7. Status and potential of terrestrial carbon sequestration in West Virginia

    Science.gov (United States)

    Benktesh D. Sharma; Jingxin. Wang

    2011-01-01

    Terrestrial ecosystem management offers cost-effective ways to enhance carbon (C) sequestration. This study utilized C stock and C sequestration in forest and agricultural lands, abandoned mine lands, and harvested wood products to estimate the net current annual C sequestration in West Virginia. Several management options within these components were simulated using a...

  8. Origins of the terrestrial flora: A symbiosis with fungi?

    Directory of Open Access Journals (Sweden)

    Selosse Marc-André

    2015-01-01

    Full Text Available Land phototrophs need to exploit both atmosphere (providing gas and light and substrate (furnishing water and minerals. Yet, their algal ancestors were poorly pre-adapted to such a life at the interface. We review the paleontological evidence that fungal symbioses which can exploit substrate resources, helped adaptation to land constraints. Diverse structures dating back to the Devonian present convincing evidence for lichens, (symbioses between fungi and microscopic algae but fossils remain scarce, so that early lichen abundance and ecological relevance remain questionable. Several enigmatic but abundant fossils from the Siluro-Devonian, such as Spongiophytonor the giant Prototaxites (Nematophytes, likely represent fungus-algal symbioses, which shaped early terrestrial ecosystems. Yet, these taxa are fully extinct, and do not have clear affinities with extant groups. Finally, terrestrialization of Embryophyta (land plants, which currently dominate land ecosystems, is linked to a symbiosis with Glomeromycetes. Today, these fungi form arbuscular mycorrhizae, which help most Embryophyta to exploit soil, and molecular data combined with paleontological evidence support the idea that this type of association is ancestral. The role of symbiotic Mucoromycetes during terrestrialization is not fully understood and mycorrhizal association diversified later in the evolution of Embryophyta. Fungal-algal symbioses thus recurrently contributed to terrestrialization of phototrophs.

  9. A Comparison of Close-Range Photogrammetry to Terrestrial Laser ...

    African Journals Online (AJOL)

    This paper describes the photogrammetric and laser scan survey of an excavated section of the Laetoli hominid track-way in Tanzania. The survey was designed to allow for comparison to a prior detailed survey of the track-way carried out in 1995, and serves as a means to compare terrestrial laser scanning with ...

  10. Microalgal and terrestrial transport biofuels to displace fossil fuels

    NARCIS (Netherlands)

    Reijnders, L.

    2009-01-01

    Terrestrial transport biofuels differ in their ability to replace fossil fuels. When both the conversion of solar energy into biomass and the life cycle inputs of fossil fuels are considered, ethanol from sugarcane and biodiesel from palm oil do relatively well, if compared with ethanol from corn,

  11. The terrestrial invertebrate fauna of a temporary stream in southern ...

    African Journals Online (AJOL)

    The terrestrial invertebrate fauna of an intermittent stream was examined in the absence of surface flows within the context of the flood pulse concept. ... The concept of the flood pulse should be expanded to include aseasonal and secular variations in flow which in temporary streams create lateral movements that provide ...

  12. Remote sensing the vulnerability of vegetation in natural terrestrial ecosystems

    Science.gov (United States)

    Alistair M. S. Smith; Crystal A. Kolden; Wade T. Tinkham; Alan F. Talhelm; John D. Marshall; Andrew T. Hudak; Luigi Boschetti; Michael J. Falkowski; Jonathan A. Greenberg; John W. Anderson; Andrew Kliskey; Lilian Alessa; Robert F. Keefe; James R. Gosz

    2014-01-01

    Climate change is altering the species composition, structure, and function of vegetation in natural terrestrial ecosystems. These changes can also impact the essential ecosystem goods and services derived from these ecosystems. Following disturbances, remote-sensing datasets have been used to monitor the disturbance and describe antecedent conditions as a means of...

  13. Conservation and monitoring of invertebrates in terrestrial protected areas

    OpenAIRE

    Melodie A. McGeoch; Hendrik Sithole; Samways, Michael J.; Simaika, John P; Pryke, James S.; Mike Picker; Charmaine Uys; Armstrong, Adrian J.; Ansie S. Dippenaar-Schoeman; Ian A. Engelbrecht; Brigitte Braschler; Michelle Hamer

    2011-01-01

    Invertebrates constitute a substantial proportion of terrestrial and freshwater biodiversity and are critical to ecosystem function. However, their inclusion in biodiversity monitoring and conservation planning and management has lagged behind better-known, more widely appreciated taxa. Significant progress in invertebrate surveys, systematics and bioindication, both globally and locally, means that their use in biodiversity monitoring and conservation is becoming increasingly feasible. Here ...

  14. Automatic registration of terrestrial point cloud using panoramic reflectance images

    NARCIS (Netherlands)

    Kang, Z.

    2008-01-01

    Much attention is paid to registration of terrestrial point clouds nowadays. Research is carried out towards improved efficiency and automation of the registration process. This paper reports a new approach for point clouds registration utilizing reflectance panoramic images. The approach follows a

  15. Terrestrial Solar Power Plants - Current Perspectives and Long Term Visions

    Science.gov (United States)

    Faiman, D.

    2004-12-01

    For terrestrial photovoltaic systems to be viable alternatives to satellite-borne solar generators, two conditions are necessary: Low-cost power generation and low-loss power transmission. This review will deal mainly with the power generation aspect of Very Large Scale terrestrial PV systems, for which it will be argued that system costs of less than $1000/kW may be achievable via the use of concentrator photovoltaic (CPV) technology. Such system costs should be directly competitive with fossil-fuelled ground-based power plants without the need for subsidies. As such, they could be readily integrated into the existing terrestrial grid systems in appropriate parts of the world. Regarding the transmission aspect, technological improvements are to be expected in low-loss long- distance cables - possibly via the discovery of hightemperature superconducting materials. This could enable the creation of a trans-equatorial power grid that, like satellite-borne systems, would ensure that the sun always shines on the generators. Key words: terrestrial solar energy, photovoltaics, dishconcentrators, low-cost electricity

  16. Inventory of Some Environmental Components in the Terrestrial and ...

    African Journals Online (AJOL)

    A survey of some environmental components in the terrestrial and aquatic ecosystems in the Integrated Waste Treatment Facility in Makurdi was carried out to obtain baseline information on the area. Inventory, semi-structured interviews and field observations/walks were carried out to obtain information on useful plants, ...

  17. Synthetic spectra of simulated terrestrial atmospheres containing possible biomarker gases

    Science.gov (United States)

    Schindler, T. L.; Kasting, J. F.

    2000-01-01

    NASA's proposed Terrestrial Planet Finder, a space-based interferometer, will eventually allow spectroscopic analyses of the atmospheres of extrasolar planets. Such analyses would provide information about the existence of life on these planets. One strategy in the search for life is to look for evidence of O3 (and hence O2) in a planet's atmosphere; another is to look for gases that might be present in an atmosphere analogous to that of the inhabited early Earth. In order to investigate these possibilities, we have calculated synthetic spectra for several hypothetical terrestrial-type atmospheres. The model atmospheres represent four different scenarios. The first two, representing inhabited terrestrial planets, are an Earth-like atmosphere containing variable amounts of oxygen and an early Earth-type atmosphere containing methane. In addition, two cases representing Mars-like and early Venus-like atmospheres were evaluated, to provide possible "false positive" spectra. The calculated spectra suggest that ozone could be detected by an instrument like Terrestrial Planet Finder if the O2 concentration in the planet's atmosphere is > or = 200 ppm, or 10(-3) times the present atmospheric level. Methane should be observable on an early-Earth type planet if it is present in concentrations of 100 ppm or more. Methane has both biogenic and abiogenic sources, but concentrations exceeding 1000 ppm, or 0.1% by volume, would be difficult to produce from abiogenic sources alone. High methane concentrations in a planet's atmosphere are therefore another potential indicator for extraterrestrial life.

  18. Terrestrial acidification during the end-Permian biosphere crisis?

    NARCIS (Netherlands)

    Sephton, Mark A.; Jiao, Dan; Engel, Michael H.; Looy, Cindy V.; Visscher, Henk

    Excessive acid rainfall associated with emplacement of the Siberian Traps magmatic province is increasingly accepted as a major contributing factor to the end-Permian biosphere crisis. However, direct proxy evidence of terrestrial acidification is so far not available. In this paper, we seek to

  19. Terrestrial species viability assessments for national forests in northeastern Washington

    Science.gov (United States)

    William L. Gaines; Barbara C. Wales; Lowell H. Suring; James S. Begley; Kim Mellen-McLean; Shawne. Mohoric

    2017-01-01

    We developed a process to address terrestrial wildlife species for which management for ecosystem diversity may be inadequate for providing ecological conditions capable of sustaining viable populations. The process includes (1) identifying species of conservation concern, (2) describing source habitats, and other important ecological factors, (3) organizing species...

  20. Incorporation of microplastics from litter into burrows of Lumbricus terrestris

    NARCIS (Netherlands)

    Huerta Lwanga, Esperanza; Gertsen, H.F.; Gooren, H.; Peters, P.; Salanki, T.E.; Ploeg, van der M.; Besseling, E.; Koelmans, A.A.; Geissen, V.

    2017-01-01

    Pollution caused by plastic debris is an urgent environmental problem. Here, we assessed the effects of microplastics in the soil surface litter on the formation and characterization of burrows built by the anecic earthworm Lumbricus terrestris in soil and quantified the amount of microplastics that

  1. DECIPHERING THERMAL PHASE CURVES OF DRY, TIDALLY LOCKED TERRESTRIAL PLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Koll, Daniel D. B.; Abbot, Dorian S., E-mail: dkoll@uchicago.edu [Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637 (United States)

    2015-03-20

    Next-generation space telescopes will allow us to characterize terrestrial exoplanets. To do so effectively it will be crucial to make use of all available data. We investigate which atmospheric properties can, and cannot, be inferred from the broadband thermal phase curve of a dry and tidally locked terrestrial planet. First, we use dimensional analysis to show that phase curves are controlled by six nondimensional parameters. Second, we use an idealized general circulation model to explore the relative sensitivity of phase curves to these parameters. We find that the feature of phase curves most sensitive to atmospheric parameters is the peak-to-trough amplitude. Moreover, except for hot and rapidly rotating planets, the phase amplitude is primarily sensitive to only two nondimensional parameters: (1) the ratio of dynamical to radiative timescales and (2) the longwave optical depth at the surface. As an application of this technique, we show how phase curve measurements can be combined with transit or emission spectroscopy to yield a new constraint for the surface pressure and atmospheric mass of terrestrial planets. We estimate that a single broadband phase curve, measured over half an orbit with the James Webb Space Telescope, could meaningfully constrain the atmospheric mass of a nearby super-Earth. Such constraints will be important for studying the atmospheric evolution of terrestrial exoplanets as well as characterizing the surface conditions on potentially habitable planets.

  2. Herbivores Enforce Sharp Boundaries Between Terrestrial and Aquatic Ecosystems

    NARCIS (Netherlands)

    Sarneel, Judith M.; Huig, N.; Veen, G. F.; Rip, W.; Bakker, E. S.

    2014-01-01

    The transitions between ecosystems (ecotones) are often biodiversity hotspots, but we know little about the forces that shape them. Today, often sharp boundaries with low diversity are found between terrestrial and aquatic ecosystems. This has been attributed to environmental factors that hamper

  3. 76 FR 50274 - Terrestrial Environmental Studies for Nuclear Power Stations

    Science.gov (United States)

    2011-08-12

    ... COMMISSION Terrestrial Environmental Studies for Nuclear Power Stations AGENCY: Nuclear Regulatory Commission... Environmental Studies for Nuclear Power Stations.'' This guide provides technical guidance that the NRC staff... nuclear power reactors. DATES: Submit comments by October 11, 2011. Comments received after this date will...

  4. Rare terrestrial orchids on Mbeya Peak, Southern Tanzania | van ...

    African Journals Online (AJOL)

    Disa walteri, Satyrium aberrans, S. comptum and S. johnsonii are rare terrestrial orchids that co-occur and flower around the same time in southern Tanzania. We found the first three of these species on Mbeya Peak in March 2005, about 45 years after they were last recorded by botanists and present the first illustration of D.

  5. Osmotic stress tolerance in semi-terrestrial tardigrades

    DEFF Research Database (Denmark)

    Heidemann, Nanna W T; Smith, Daniel K.; Hygum, Thomas L.

    2016-01-01

    Little is known about ionic and osmotic stress tolerance in tardigrades. Here, we examine salt stress tolerance in Ramazzottius oberhaeuseri and Echiniscus testudo from Nivå (Denmark) and address whether limno-terrestrial tardigrades can enter a state of quiescence (osmobiosis) in the face of high...

  6. Contemporary climate change and terrestrial invertebrates : Evolutionary versus plastic changes

    NARCIS (Netherlands)

    Schilthuizen, Menno; Kellermann, Vanessa

    To forecast the responses of species to future climate change, an understanding of the ability of species to adapt to long-term shifts in temperature is crucial. We present a review on evolutionary adaptation and phenotypic plasticity of temperature-related traits in terrestrial invertebrates. The

  7. Facial trauma among victims of terrestrial transport accidents.

    Science.gov (United States)

    d'Avila, Sérgio; Barbosa, Kevan Guilherme Nóbrega; Bernardino, Ítalo de Macedo; da Nóbrega, Lorena Marques; Bento, Patrícia Meira; E Ferreira, Efigênia Ferreira

    2016-01-01

    In developing countries, terrestrial transport accidents - TTA, especially those involving automobiles and motorcycles - are a major cause of facial trauma, surpassing urban violence. This cross-sectional census study attempted to determine facial trauma occurrence with terrestrial transport accidents etiology, involving cars, motorcycles, or accidents with pedestrians in the northeastern region of Brazil, and examine victims' socio-demographic characteristics. Morbidity data from forensic service reports of victims who sought care from January to December 2012 were analyzed. Altogether, 2379 reports were evaluated, of which 673 were related to terrestrial transport accidents and 103 involved facial trauma. Three previously trained and calibrated researchers collected data using a specific form. Facial trauma occurrence rate was 15.3% (n=103). The most affected age group was 20-29 years (48.3%), and more men than women were affected (2.81:1). Motorcycles were involved in the majority of accidents resulting in facial trauma (66.3%). The occurrence of facial trauma in terrestrial transport accident victims tends to affect a greater proportion of young and male subjects, and the most prevalent accidents involve motorcycles. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  8. Shell bone histology indicates terrestrial palaeoecology of basal turtles.

    Science.gov (United States)

    Scheyer, Torsten M; Sander, P Martin

    2007-08-07

    The palaeoecology of basal turtles from the Late Triassic was classically viewed as being semi-aquatic, similar to the lifestyle of modern snapping turtles. Lately, this view was questioned based on limb bone proportions, and a terrestrial palaeoecology was suggested for the turtle stem. Here, we present independent shell bone microstructural evidence for a terrestrial habitat of the oldest and basal most well-known turtles, i.e. the Upper Triassic Proterochersis robusta and Proganochelys quenstedti. Comparison of their shell bone histology with that of extant turtles preferring either aquatic habitats or terrestrial habitats clearly reveals congruence with terrestrial turtle taxa. Similarities in the shell bones of these turtles are a diploe structure with well-developed external and internal cortices, weak vascularization of the compact bone layers and a dense nature of the interior cancellous bone with overall short trabeculae. On the other hand, 'aquatic' turtles tend to reduce cortical bone layers, while increasing overall vascularization of the bone tissue. In contrast to the study of limb bone proportions, the present study is independent from the uncommon preservation of appendicular skeletal elements in fossil turtles, enabling the palaeoecological study of a much broader range of incompletely known turtle taxa in the fossil record.

  9. A review of climate change effects on terrestrial rangeland birds

    Science.gov (United States)

    D. M. Finch; K. E. Bagne; M. M. Friggens; D. M. Smith; K. M. Brodhead

    2011-01-01

    We evaluated existing literature on predicted and known climate change effects on terrestrial rangeland birds. We asked the following questions: 1) How does climate change affect birds? 2) How will birds respond to climate change? 3) Are species already responding? 4) How will habitats be impacted?

  10. Isotopic tracers for net primary productivity for a terrestrial esocystem ...

    African Journals Online (AJOL)

    The coupling effect of vapour release and CO2 uptake during photosynthesis plays an important role in the carbon and hydrologic cycles. The water use efficiency (WUE) for transpiration was used in calculating the net primary productivity (NPP) for terrestrial ecosystem. Three parameters were used in calculating the water ...

  11. 171 inventory of some environmental components in the terrestrial ...

    African Journals Online (AJOL)

    2010-09-02

    Sep 2, 2010 ... ABSTRACT. A survey of some environmental components in the terrestrial and aquatic ecosystems in the. Integrated Waste Treatment Facility in Makurdi was carried out to obtain baseline information on the area. Inventory, semi-structured interviews and field observations/walks were carried out to obtain ...

  12. Annotated Checklist of the Terrestrial Gastropods of Nepal

    Science.gov (United States)

    Budha, Prem B.; Naggs, Fred; Backeljau, Thierry

    2015-01-01

    Abstract This is the very first checklist of the terrestrial gastropods of Nepal. It includes 138 species and six subspecies, of which 22 species are endemic and four are introduced. It highlights 34 species recorded for the first time in Nepal and provides new distribution records for another 30 species. PMID:25878541

  13. Heinrich event 4 characterized by terrestrial proxies in southwestern Europe

    Directory of Open Access Journals (Sweden)

    J. M. López-García

    2013-05-01

    Full Text Available Heinrich event 4 (H4 is well documented in the North Atlantic Ocean as a cooling event that occurred between 39 and 40 Ka. Deep-sea cores around the Iberian Peninsula coastline have been analysed to characterize the H4 event, but there are no data on the terrestrial response to this event. Here we present for the first time an analysis of terrestrial proxies for characterizing the H4 event, using the small-vertebrate assemblage (comprising small mammals, squamates and amphibians from Terrassa Riera dels Canyars, an archaeo-palaeontological deposit located on the seaboard of the northeastern Iberian Peninsula. This assemblage shows that the H4 event is characterized in northeastern Iberia by harsher and drier terrestrial conditions than today. Our results were compared with other proxies such as pollen, charcoal, phytolith, avifauna and large-mammal data available for this site, as well as with the general H4 event fluctuations and with other sites where H4 and the previous and subsequent Heinrich events (H5 and H3 have been detected in the Mediterranean and Atlantic regions of the Iberian Peninsula. We conclude that the terrestrial proxies follow the same patterns as the climatic and environmental conditions detected by the deep-sea cores at the Iberian margins.

  14. Experimental Study Of Terrestrial Electron Anti-neutrinos With Kamland

    CERN Document Server

    Tolich, N R

    2005-01-01

    The analysis presented here uses Kamioka Liquid scintillator Anti-Neutrino Detector (KamLAND) to measure the rate of electron anti-neutrinos, ne&d1;' s , produced from terrestrial 238U and 212Th. 238U and 212Th are thought to be the main heat source driving mantle convection in the Earth, which in turn is responsible for plate tectonics. The total terrestrial 238U and 212Th content has been estimated from Earth models and rock samples from a very small fraction of the Earth. Until now there have been no direct measurements. Since ne&d1;' s have an exceedingly small cross section, they propagate undisturbed in the Earth interior, and their measurement near the Earth surface can be used to gain information on their sources. Based on a total of (2.63 ± 0.19) × 1031 target proton-years (0.506 kton- years), the 90% confidence interval for the total number of terrestrial 238U and 212Th ne&d1;' s detected is 4 to 40. This is consistent with the best models of terrestrial 23...

  15. Recent patterns and mechanisms of carbon exchange by terrestrial ecosystems

    CSIR Research Space (South Africa)

    Schimel, DS

    2001-11-08

    Full Text Available Knowledge of carbon exchange between the atmosphere, land and the oceans is important, given that the terrestrial and marine environments are currently absorbing about half of the carbon dioxide that is emitted by fossil-fuel combustion. This carbon...

  16. Enchytraeids as indicator organisms for chemical stress in terrestrial ecosystems

    NARCIS (Netherlands)

    Didden, W.; Römbke, J.

    2001-01-01

    This review article surveys the available data on enchytraeid sensitivity toward chemical stress, and the effects of chemical stress on enchytraeid communities in terrestrial ecosystems. The factors affecting bioavailability of stressors to enchytraeids and the nature of direct and indirect effects

  17. Effects of Timber Harvests and Silvicultural Edges on Terrestrial Salamanders

    Science.gov (United States)

    MacNeil, Jami E.; Williams, Rod N.

    2014-01-01

    Balancing timber production and conservation in forest management requires an understanding of how timber harvests affect wildlife species. Terrestrial salamanders are useful indicators of mature forest ecosystem health due to their importance to ecosystem processes and sensitivity to environmental change. However, the effects of timber harvests on salamanders, though often researched, are still not well understood. To further this understanding, we used artificial cover objects to monitor the relative abundance of terrestrial salamanders for two seasons (fall and spring) pre-harvest and five seasons post-harvest in six forest management treatments, and for three seasons post-harvest across the edge gradients of six recent clearcuts. In total, we recorded 19,048 encounters representing nine species of salamanders. We observed declines in mean encounters of eastern red-backed salamanders (Plethodon cinereus) and northern slimy salamanders (P. glutinosus) from pre- to post-harvest in group selection cuts and in clearcuts. However, we found no evidence of salamander declines at shelterwoods and forested sites adjacent to harvests. Edge effects induced by recent clearcuts influenced salamanders for approximately 20 m into the forest, but edge influence varied by slope orientation. Temperature, soil moisture, and canopy cover were all correlated with salamander counts. Our results suggest silvicultural techniques that remove the forest canopy negatively affect salamander relative abundance on the local scale during the years immediately following harvest, and that the depth of edge influence of clearcuts on terrestrial salamanders is relatively shallow (harvests (<4 ha) and techniques that leave the forest canopy intact may be compatible with maintaining terrestrial salamander populations across a forested landscape. Our results demonstrate the importance of examining species-specific responses and monitoring salamanders across multiple seasons and years. Long

  18. Climate-mediated spatiotemporal variability in terrestrial productivity across Europe

    Science.gov (United States)

    Wu, X.; Babst, F.; Ciais, P.; Frank, D.; Reichstein, M.; Wattenbach, M.; Zang, C.; Mahecha, M. D.

    2014-06-01

    Quantifying the interannual variability (IAV) of the terrestrial ecosystem productivity and its sensitivity to climate is crucial for improving carbon budget predictions. In this context it is necessary to disentangle the influence of climate from impacts of other mechanisms underlying the spatiotemporal patterns of IAV of the ecosystem productivity. In this study we investigated the spatiotemporal patterns of IAV of historical observations of European crop yields in tandem with a set of climate variables. We further evaluated if relevant remote-sensing retrievals of NDVI (normalized difference vegetation index) and FAPAR (fraction of absorbed photosynthetically active radiation) depict a similar behaviour. Our results reveal distinct spatial patterns in the IAV of the analysed proxies linked to terrestrial productivity. In particular, we find higher IAV in water-limited regions of Europe (Mediterranean and temperate continental Europe) compared to other regions in both crop yield and remote-sensing observations. Our results further indicate that variations in the water balance during the active growing season exert a more pronounced and direct effect than variations of temperature on explaining the spatial patterns in IAV of productivity-related variables in temperate Europe. Overall, we observe a temporally increasing trend in the IAV of terrestrial productivity and an increasing sensitivity of productivity to water availability in dry regions of Europe during the 1975-2009 period. In the same regions, a simultaneous increase in the IAV of water availability was detected. These findings suggest intricate responses of carbon fluxes to climate variability in Europe and that the IAV of terrestrial productivity has become potentially more sensitive to changes in water availability in the dry regions in Europe. The changing sensitivity of terrestrial productivity accompanied by the changing IAV of climate is expected to impact carbon stocks and the net carbon balance

  19. Preparation and characterization of Tribulus terrestris-loaded nanoparticles

    Directory of Open Access Journals (Sweden)

    M. Khanavi*

    2017-11-01

    Full Text Available Background and objectives: Tribulus terrestris is a flowering herb (Zygophyllaceae with several properties in folk medicine such as diuretic, tonic, aphrodisiac, analgesic, astringent, and stomachic-lithotripter activities. Although, some extracts and phytochemicals represent excellent bio-activity in vitro, less or no in vivo activity is observed due to their improper molecular size. The intend of this research was investigation of the feasibility of encapsulating T. terrestris into [poly (lactic-co-glycolic acid] PLGA nanoparticles. Methods: Aerial parts of the plant were extracted with aqueous ethanol 85% by percolation apparatus. The nanoparticles of T. terrestris-loaded were prepared using a modified simultaneous double-emulsion solvent evaporation/diffusion method. Elucidations were made on the basis of scanning electron microscopy (SEM and differential scanning calorimetry (DSC. The content of nanoparticles was analyzed by HPLC with indirect method. Results: The results stated that increasing the portion of plant extract could cause bigger size with no considerable increase in polydispersity index (PDI. The encapsulation efficiency of T. terrestris-loaded nanoparticles was 40.3 to 78.5 and the drug loadings were 0.806 to 6.104, with different ratios of extract. The overall pattern of the release in SDS 1% in dialysis bag in all formulations showed similar and biphasic release kinetic, an initial burst release in the first day followed by constant release over 10 days. Conclusion: An effective approach for the preparation of T. terrestris-loaded PLGA nanoparticles was performed. The controlled release profile showed that these biodegradable PLGA nanoparticles had great potential and should be given particular consideration in further biological researches.

  20. NASA HRP Immunology Discipline - Use of Terrestrial Analogs

    Science.gov (United States)

    Crucian, Brian

    2014-01-01

    Due to the cost and operational constraints, as well as technical implementation limitations, it is desirous to perform relevant space physiology investigations first in terrestrial 'space analogs'. This is particularly true for initial investigations, which may then provide appropriate focus for subsequent flight investigations, or for mechanistic investigations that simply cannot be performed during spaceflight. Appropriate analog choice is extremely important. There are a wide variety of terrestrial space analogs, each relevant to a particular physiological discipline (or disciplines) and each with a particular fidelity (or lack thereof) to spaceflight, and each with unique operational constraints. The HRP Immunology Discipline is tasked with managing the HRP Risk concerning clinical risk for Astronaut crews related to spaceflight-associated immune dysregulation. Such dysregulation has been documented to occur during spaceflight, and found to persist for the duration of a 6-month ISS mission. Studies continue to characterize the onorbit phenomenon, but it generally consists of diminished immunocyte function, dysregulated cytokine profiles, and persistent herpesvirus reactivation. Causes are thought to synergistically include microgravity, psychological or physiological stress, radiation, and/or circadian misalignment. An appropriate terrestrial analog for immune dysregulation would replicate as many of these influences as possible. Such analogs may include clinostat or bioreactor cell culture (microgravity), hindlimb suspension (stress, fluid shifts, hypokinesis), or human deployment to remote or extreme environments (isolation, stress, circadian). Also, the laboratory setting may be used as an analog, or to augment analogs, such as sleep deprivation/misalignment or human centrifugation to replicate gravitational stress. As an appropriate example of a NASA Disciplines use of Terrestrial space analogs, this talk will discuss spaceflight associated immune

  1. The terrestrial carbon cycle on the regional and global scale : modeling, uncertainties and policy relevance

    NARCIS (Netherlands)

    Minnen, van J.G.

    2008-01-01

    Contains the chapters: The importance of three centuries of climate and land-use change for the global and regional terrestrial carbon cycle; and The terrestrial C cycle and its role in the climate change policy

  2. Impact of non-native terrestrial mammals on the structure of the terrestrial mammal food web of Newfoundland, Canada.

    Directory of Open Access Journals (Sweden)

    Justin S Strong

    Full Text Available The island of Newfoundland is unique because it has as many non-native terrestrial mammals as native ones. The impacts of non-native species on native flora and fauna can be profound and invasive species have been identified as one of the primary drivers of species extinction. Few studies, however, have investigated the effects of a non-native species assemblage on community and ecosystem properties. We reviewed the literature to build the first terrestrial mammal food web for the island of Newfoundland and then used network analyses to investigate how the timing of introductions and trophic position of non-native species has affected the structure of the terrestrial mammal food web in Newfoundland. The first non-native mammals (house mouse and brown rat became established in Newfoundland with human settlement in the late 15th and early 16th centuries. Coyotes and southern red-backed voles are the most recent mammals to establish themselves on the island in 1985 and 1998, respectively. The fraction of intermediate species increased with the addition of non-native mammals over time whereas the fraction of basal and top species declined over time. This increase in intermediate species mediated by non-native species arrivals led to an overall increase in the terrestrial mammal food web connectance and generality (i.e. mean number of prey per predator. This diverse prey base and sources of carrion may have facilitated the natural establishment of coyotes on the island. Also, there is some evidence that the introduction of non-native prey species such as the southern red-backed vole has contributed to the recovery of the threatened American marten. Long-term monitoring of the food web is required to understand and predict the impacts of the diverse novel interactions that are developing in the terrestrial mammal food web of Newfoundland.

  3. Detection of antibody against limax amoebae by means of the indirect haemagglutination test.

    Science.gov (United States)

    Cerva, L

    1977-01-01

    A detailed description is given of the procuedure of the indirect haemagglutination test employed in the detection of specific antibodies against pathogenic amoebae of the genera Naegleria and Acanthamoeba. The preservation of all ingredients obtained by lyophilisation provide for a standard pattern of the test. The results of the test with experimentally prepared immune rabbit sera demonstrate an antigenic uniformity of the various isolates of Naegleria fowleri, and their marked difference from Acanthamoeba.

  4. Applications of landscape genetics to connectivity research in terrestrial animals [Chapter 12

    Science.gov (United States)

    Lisette P. Waits; Samuel A. Cushman; Steve F. Spear

    2016-01-01

    Landscape genetic studies have focused on terrestrial animals more than any other taxonomic group. This chapter focuses on applications of landscape genetics for understanding connectivity of terrestrial animal populations. It starts with a general introduction covering unique characteristics and challenges of the terrestrial study system. This is followed by...

  5. Trends and Future Challenges in Sampling the Deep Terrestrial Biosphere

    Directory of Open Access Journals (Sweden)

    Michael J Wilkins

    2014-09-01

    Full Text Available Research in the deep terrestrial biosphere is driven by interest in novel biodiversity and metabolisms, biogeochemical cycling, and the impact of human activities on this ecosystem. As this interest continues to grow, it is important to ensure that when subsurface investigations are proposed, materials recovered from the subsurface are sampled and preserved in an appropriate manner to limit contamination and ensure preservation of accurate microbial, geochemical, and mineralogical signatures. On February 20th, 2014, a workshop on Trends and Future Challenges in Sampling The Deep Subsurface was coordinated in Columbus, Ohio by The Ohio State University and West Virginia University faculty, and sponsored by The Ohio State University and the Sloan Foundation’s Deep Carbon Observatory. The workshop aims were to identify and develop best practices for the collection, preservation, and analysis of terrestrial deep rock samples. This document summarizes the information shared during this workshop.

  6. Reduction and identification for hybrid dynamical models of terrestrial locomotion

    Science.gov (United States)

    Burden, Samuel A.; Sastry, S. Shankar

    2013-06-01

    The study of terrestrial locomotion has compelling applications ranging from design of legged robots to development of novel prosthetic devices. From a first-principles perspective, the dynamics of legged locomotion seem overwhelmingly complex as nonlinear rigid body dynamics couple to a granular substrate through viscoelastic limbs. However, a surfeit of empirical data demonstrates that animals use a small fraction of their available degrees-of-freedom during locomotion on regular terrain, suggesting that a reduced-order model can accurately describe the dynamical variation observed during steady-state locomotion. Exploiting this emergent phenomena has the potential to dramatically simplify design and control of micro-scale legged robots. We propose a paradigm for studying dynamic terrestrial locomotion using empirically-validated reduced{order models.

  7. How the Red Queen drives terrestrial mammals to extinction.

    Science.gov (United States)

    Quental, Tiago B; Marshall, Charles R

    2013-07-19

    Most species disappear by the processes of background extinction, yet those processes are poorly understood. We analyzed the evolutionary dynamics of 19 Cenozoic terrestrial mammalian clades with rich fossil records that are now fully extinct or in diversity decline. We find their diversity loss was not just a consequence of "gamblers ruin" but resulted from the evolutionary loss to the Red Queen, a failure to keep pace with a deteriorating environment. Diversity loss is driven equally by both depressed origination rates and elevated extinction rates. Although we find diversity-dependent origination and extinction rates, the diversity of each clade only transiently equaled the implied equilibrium diversity. Thus, the processes that drove diversity loss in terrestrial mammal clades were fundamentally nonequilibrial and overwhelmed diversity-dependent processes.

  8. Optimal Strategies for Probing Terrestrial Exoplanet Atmospheres with JWST

    Science.gov (United States)

    Batalha, Natasha E.; Lewis, Nikole K.; Line, Michael

    2018-01-01

    It is imperative that the exoplanet community determines the feasibility and the resources needed to yield high fidelity atmospheric compositions from terrestrial exoplanets. In particular, LHS 1140b and the TRAPPIST-1 system, already slated for observations by JWST’s Guaranteed Time Observers, will be the first two terrestrial planets observed by JWST. I will discuss optimal observing strategies for observing these two systems, focusing on the NIRSpec Prism (1-5μm) and the combination of NIRISS SOSS (1-2.7μm) and NIRSpec G395H (3-5μm). I will also introduce currently unsupported JWST readmodes that have the potential to greatly increase the precision on our atmospheric spectra. Lastly, I will use information content theory to compute the expected confidence interval on the retrieved abundances of key molecular species and temperature profiles as a function of JWST observing cycles.

  9. Nanotechnologies and regenerative medical approaches for space and terrestrial medicine.

    Science.gov (United States)

    Grattoni, Alessandro; Tasciotti, Ennio; Fine, Daniel; Fernandez-Moure, Joseph S; Sakamoto, Jason; Hu, Ye; Weiner, Bradley; Ferrari, Mauro; Parazynski, Scott

    2012-11-01

    One purpose of the International Space Station (ISS) is to explore powerful new areas of biomedical science in microgravity. Recent advances in nanotechnology applied to medicine--what we now refer to as nano-medicine--and regenerative medicine have enormous untapped potential for future space and terrestrial medical applications. Novel means for drug delivery and nanoscale screening tools will one day benefit astronauts venturing to Mars and places beyond, while the space laboratory will foster advances in nanotechnologies for diagnostic and therapeutic tools to help our patients here on Earth. Herein we review a series of nanotechnologies and selected regenerative medical approaches and highlight key areas of ongoing and future investigation that will benefit both space and terrestrial medicine. These studies target significant areas of human disease such as osteoporosis, diabetes, radiation injury, and many others.

  10. Ecological Biogeography of the Terrestrial Nematodes of Victoria Land, Antarctica

    Science.gov (United States)

    Adams, Byron J.; Wall, Diana H.; Virginia, Ross A.; Broos, Emma; Knox, Matthew A.

    2014-01-01

    Abstract The terrestrial ecosystems of Victoria Land, Antarctica are characteristically simple in terms of biological diversity and ecological functioning. Nematodes are the most commonly encountered and abundant metazoans of Victoria Land soils, yet little is known of their diversity and distribution. Herein we present a summary of the geographic distribution, habitats and ecology of the terrestrial nematodes of Victoria Land from published and unpublished sources. All Victoria Land nematodes are endemic to Antarctica, and many are common and widely distributed at landscape scales. However, at smaller spatial scales, populations can have patchy distributions, with the presence or absence of each species strongly influenced by specific habitat requirements. As the frequency of nematode introductions to Antarctica increases, and soil habitats are altered in response to climate change, our current understanding of the environmental parameters associated with the biogeography of Antarctic nematofauna will be crucial to monitoring and possibly mitigating changes to these unique soil ecosystems. PMID:25061360

  11. Extreme alien light allows survival of terrestrial bacteria

    Science.gov (United States)

    Johnson, Neil; Zhao, Guannan; Caycedo, Felipe; Manrique, Pedro; Qi, Hong; Rodriguez, Ferney; Quiroga, Luis

    2013-07-01

    Photosynthetic organisms provide a crucial coupling between the Sun's energy and metabolic processes supporting life on Earth. Searches for extraterrestrial life focus on seeking planets with similar incident light intensities and environments. However the impact of abnormal photon arrival times has not been considered. Here we present the counterintuitive result that broad classes of extreme alien light could support terrestrial bacterial life whereas sources more similar to our Sun might not. Our detailed microscopic model uses state-of-the-art empirical inputs including Atomic Force Microscopy (AFM) images. It predicts a highly nonlinear survivability for the basic lifeform Rsp. Photometricum whereby toxic photon feeds get converted into a benign metabolic energy supply by an interplay between the membrane's spatial structure and temporal excitation processes. More generally, our work suggests a new handle for manipulating terrestrial photosynthesis using currently-available extreme value statistics photon sources.

  12. Indicator organisms for marine and terrestrial environmental radioactivity[Radioecology

    Energy Technology Data Exchange (ETDEWEB)

    Raaum, A.; Christensen, G.C.; Ruud, A.M.B.; Straelberg, E. [Institute for Energy Technology, IFE, Kjeller (Norway)

    2006-04-15

    The aim of this work was to study different terrestrial and marine indicator organisms for environmental radioactivity. An area in central Norway, consisting of forests, mountain forests and high mountains without forests was subject to the study for terrestrial indicator organisms. This area received fairly high contamination of Chernobyl fallout. In 1990 samples of several species of biota were collected from the same area as a part of a NKS project. For marine indicator organisms, samples of the two species of brown algae Fucus vesiculosus and Ascophyllum nodosum were collected from Tromoeya in southern Norway. Seasonal variations in activity concentrations and indicator properties of Fucus vesiculosus and Ascophyllum nodosum were compared for several radionuclides, including some radionuclides that have not been focused on previously. (au)

  13. Trends and Future Challenges in Sampling the Deep Terrestrial Biosphere

    Energy Technology Data Exchange (ETDEWEB)

    Wilkins, Michael J.; Daly, Rebecca; Mouser, Paula J.; Trexler, Ryan; Sharma, Shihka; Cole, David R.; Wrighton, Kelly C.; Biddle , Jennifer F.; Denis, Elizabeth; Fredrickson, Jim K.; Kieft, Thomas L.; Onstott, T. C.; Peterson, Lee; Pfiffner, Susan M.; Phelps, Tommy J.; Schrenk, Matthew O.

    2014-09-12

    Research in the deep terrestrial biosphere is driven by interest in novel biodiversity and metabolisms, biogeochemical cycling, and the impact of human activities on this ecosystem. As this interest continues to grow, it is important to ensure that when subsurface investigations are proposed, materials recovered from the subsurface are sampled and preserved in an appropriate manner to limit contamination and ensure preservation of accurate microbial, geochemical, and mineralogical signatures. On February 20th, 2014, a workshop on “Trends and Future Challenges in Sampling The Deep Subsurface” was coordinated in Columbus, Ohio by The Ohio State University and West Virginia University faculty, and sponsored by The Ohio State University and the Sloan Foundation’s Deep Carbon Observatory. The workshop aims were to identify and develop best practices for the collection, preservation, and analysis of terrestrial deep rock samples. This document summarizes the information shared during this workshop.

  14. Climate Warming and Disease Risks for Terrestrial and Marine Biota

    Science.gov (United States)

    Harvell, C. Drew; Mitchell, Charles E.; Ward, Jessica R.; Altizer, Sonia; Dobson, Andrew P.; Ostfeld, Richard S.; Samuel, Michael D.

    2002-06-01

    Infectious diseases can cause rapid population declines or species extinctions. Many pathogens of terrestrial and marine taxa are sensitive to temperature, rainfall, and humidity, creating synergisms that could affect biodiversity. Climate warming can increase pathogen development and survival rates, disease transmission, and host susceptibility. Although most host-parasite systems are predicted to experience more frequent or severe disease impacts with warming, a subset of pathogens might decline with warming, releasing hosts from disease. Recently, changes in El Niño-Southern Oscillation events have had a detectable influence on marine and terrestrial pathogens, including coral diseases, oyster pathogens, crop pathogens, Rift Valley fever, and human cholera. To improve our ability to predict epidemics in wild populations, it will be necessary to separate the independent and interactive effects of multiple climate drivers on disease impact.

  15. Capture of terrestrial-sized moons by gas giant planets.

    Science.gov (United States)

    Williams, Darren M

    2013-04-01

    Terrestrial moons with masses >0.1 M (symbol in text) possibly exist around extrasolar giant planets, and here we consider the energetics of how they might form. Binary-exchange capture can occur if a binary-terrestrial object (BTO) is tidally disrupted during a close encounter with a giant planet and one of the binary members is ejected while the other remains as a moon. Tidal disruption occurs readily in the deep gravity wells of giant planets; however, the large encounter velocities in the wells make binary exchange more difficult than for planets of lesser mass. In addition, successful capture favors massive binaries with large rotational velocities and small component mass ratios. Also, since the interaction tends to leave the captured moons on highly elliptical orbits, permanent capture is only possible around planets with sizable Hill spheres that are well separated from their host stars.

  16. [Extrasolar terrestrial planets and possibility of extraterrestrial life].

    Science.gov (United States)

    Ida, Shigeru

    2003-12-01

    Recent development of research on extrasolar planets are reviewed. About 120 extrasolar Jupiter-mass planets have been discovered through the observation of Doppler shift in the light of their host stars that is caused by acceleration due to planet orbital motions. Although the extrasolar planets so far observed may be limited to gas giant planets and their orbits differ from those of giant planets in our Solar system (Jupiter and Saturn), the theoretically predicted probability of existence of extrasolar terrestrial planets that can have liquid water ocean on their surface is comparable to that of detectable gas giant planets. Based on the number of extrasolar gas giants detected so far, about 100 life-sustainable planets may exist within a range of 200 light years. Indirect observation of extrasolar terrestrial planets would be done with space telescopes within several years and direct one may be done within 20 years. The latter can detect biomarkers on these planets as well.

  17. Climate legacies drive global soil carbon stocks in terrestrial ecosystems.

    Science.gov (United States)

    Delgado-Baquerizo, Manuel; Eldridge, David J; Maestre, Fernando T; Karunaratne, Senani B; Trivedi, Pankaj; Reich, Peter B; Singh, Brajesh K

    2017-04-01

    Climatic conditions shift gradually over millennia, altering the rates at which carbon (C) is fixed from the atmosphere and stored in the soil. However, legacy impacts of past climates on current soil C stocks are poorly understood. We used data from more than 5000 terrestrial sites from three global and regional data sets to identify the relative importance of current and past (Last Glacial Maximum and mid-Holocene) climatic conditions in regulating soil C stocks in natural and agricultural areas. Paleoclimate always explained a greater amount of the variance in soil C stocks than current climate at regional and global scales. Our results indicate that climatic legacies help determine global soil C stocks in terrestrial ecosystems where agriculture is highly dependent on current climatic conditions. Our findings emphasize the importance of considering how climate legacies influence soil C content, allowing us to improve quantitative predictions of global C stocks under different climatic scenarios.

  18. The carbon balance of terrestrial ecosystems of China

    Directory of Open Access Journals (Sweden)

    Pilli R

    2009-05-01

    Full Text Available A comment is made on a recent letter published on Nature, in which different methodologies are applied to estimate the carbon balance of terrestrial ecosystems of China. A global carbon sink of 0.19-0.26 Pg per year is estimated during the 1980s and 1990s, and it is estimated that in 2006 terrestrial ecosystems have absorbed 28-37 per cent of global carbon emissions in China. Most of the carbon absorption is attributed to large-scale plantation made since the 1980s and shrub recovery. These results will certainly be valuable in the frame of the so-called “REDD” (Reducing Emissions from Deforestation forest Degradation in developing countries mechanism (UN convention on climate change UNFCCC.

  19. The fast development of solar terrestrial sciences in Taiwan

    Science.gov (United States)

    Liu, Jann-Yenq; Chang, Loren Chee-Wei; Chao, Chi-Kuang; Chen, Ming-Quey; Chu, Yen-Hsyang; Hau, Lin-Ni; Huang, Chien-Ming; Kuo, Cheng-Ling; Lee, Lou-Chuang; Lyu, Ling-Hsiao; Lin, Chia-Hsien; Pan, Chen-Jeih; Shue, Jih-Hong; Su, Ching-Lun; Tsai, Lung-Chih; Yang, Ya-Hui; Lin, Chien-Hung; Hsu, Rue-Ron; Su, Han-Tzong

    2016-12-01

    In Taiwan, research and education of solar terrestrial sciences began with a ground-based ionosonde operated by Ministry of Communications in 1952 and courses of ionospheric physics and space physics offered by National Central University (NCU) in 1959, respectively. Since 1990, to enhance both research and education, the Institute of Space Science at NCU has been setting up and operating ground-based observations of micropulsations, very high-frequency radar, low-latitude ionospheric tomography network, high-frequency Doppler sounder, digital ionosondes, and total electron content (TEC) derived from ground-based GPS receivers to study the morphology of the ionosphere for diurnal, seasonal, geophysical, and solar activity variations, as well as the ionosphere response to solar flares, solar wind, solar eclipses, magnetic storms, earthquakes, tsunami, and so on. Meanwhile, to have better understanding on physics and mechanisms, model simulations for the heliosphere, solar wind, magnetosphere, and ionosphere are also introduced and developed. After the 21 September 1999 Mw7.6 Chi-Chi earthquake, seismo-ionospheric precursors and seismo-traveling ionospheric disturbances induced by earthquakes become the most interesting and challenging research topics of the world. The development of solar terrestrial sciences grows even much faster after National Space Origination has been launching a series of FORMOSAT satellites since 1999. ROCSAT-1 (now renamed FORMOSAT-1) measures the ion composition, density, temperature, and drift velocity at the 600-km altitude in the low-latitude ionosphere; FORMOSAT-2 is to investigate lightning-induced transient luminous events, polar aurora, and upper atmospheric airglow, and FORMOSAT-3 probes ionospheric electron density profiles of the globe. In the near future, FORMOSAT-5 and FORMOSAT-7/COSMIC-2 will be employed for studying solar terrestrial sciences. These satellite missions play an important role on the recent development of solar

  20. Terrestrial biogeochemical cycles - Global interactions with the atmosphere and hydrology

    Science.gov (United States)

    Schimel, David S.; Parton, William J.; Kittel, Timothy G. F.

    1991-01-01

    A review is presented of developments in ecosystem theory, remote sensing, and geographic information systems that support new endeavors in spatial modeling. A paradigm has emerged to predict ecosystem behavior based on understanding responses to multiple resources. Ecosystem models couple primary production to decomposition and nutrient availability utilizing this paradigm. It is indicated that coupling of transport and ecosystem processes alters the behavior of earth system components (terrestrial ecosystems, hydrology, and the atmosphere) from that of an uncoupled model.

  1. VALUING THE IMPACTS OF CLIMATE CHANGE ON TERRESTRIAL ECOSYSTEM SERVICES

    OpenAIRE

    ALAN KRUPNICK; DAVID McLAUGHLIN

    2012-01-01

    Climate change is already having impacts on terrestrial ecosystem services and such impacts are only expected to broaden and worsen as greenhouse gas emissions (GHGs) continue at their historic levels. To set appropriate policies for reducing GHG emissions, economists recommend the use of cost-benefit analysis. To perform such analyses, the predominant approach has been to use integrated assessment models. There is a need for more targeted valuation studies to serve as further evidence about ...

  2. Forest canopy gap fraction from terrestrial laser scanning

    OpenAIRE

    Danson, F. M.; Hetherington, D; Morsdorf, F; Koetz, B; Allgöwer, B

    2007-01-01

    A terrestrial laser scanner (TLS) was used to measure canopy directional gap fraction distribution in forest stands in the Swiss National Park, eastern Switzerland. A scanner model was derived to determine the expected number of laser shots in all directions, and these data were compared with the measured number of laser hits to determine directional gap fraction at eight sampling points. Directional gap fraction distributions were determined from digital hemispherical photographs recor...

  3. Encapsulant materials for $2/watt terrestrial photovoltaic arrays

    Science.gov (United States)

    Maxwell, H.

    1978-01-01

    Materials properties, cost data, and strawman designs are presented relative to materials for $2/watt terrestrial photovoltaic arrays to meet LSA Project cost goals for 1982. It is shown that encapsulation materials can be categorized in six basic elements: top covers, super-strates, pottants, adhesives, substrates, and bottom covers. The roles of the six basic encapsulant material elements in the encapsulant system are discussed and candidate materials presented.

  4. The "human" statistics of terrestrial impact cratering rate

    OpenAIRE

    Jetsu, Lauri

    1997-01-01

    The most significant periodicities in the terrestrial impact crater record are due to the human-signal: the bias of assigning integer values for the crater ages. This bias seems to have eluded the proponents and opponents of real periodicity in the occurrence of these events, as well as the theorists searching for an extraterrestrial explanation for such periodicity. The human-signal should be seriously considered by scientists in astronomy, geology and paleontology when searching for a conne...

  5. Terrestrial Microgravity Model and Threshold Gravity Simulation using Magnetic Levitation

    Science.gov (United States)

    Ramachandran, N.

    2005-01-01

    What is the threshold gravity (minimum gravity level) required for the nominal functioning of the human system? What dosage is required? Do human cell lines behave differently in microgravity in response to an external stimulus? The critical need for such a gravity simulator is emphasized by recent experiments on human epithelial cells and lymphocytes on the Space Shuttle clearly showing that cell growth and function are markedly different from those observed terrestrially. Those differences are also dramatic between cells grown in space and those in Rotating Wall Vessels (RWV), or NASA bioreactor often used to simulate microgravity, indicating that although morphological growth patterns (three dimensional growth) can be successfully simulated using RWVs, cell function performance is not reproduced - a critical difference. If cell function is dramatically affected by gravity off-loading, then cell response to stimuli such as radiation, stress, etc. can be very different from terrestrial cell lines. Yet, we have no good gravity simulator for use in study of these phenomena. This represents a profound shortcoming for countermeasures research. We postulate that we can use magnetic levitation of cells and tissue, through the use of strong magnetic fields and field gradients, as a terrestrial microgravity model to study human cells. Specific objectives of the research are: 1. To develop a tried, tested and benchmarked terrestrial microgravity model for cell culture studies; 2. Gravity threshold determination; 3. Dosage (magnitude and duration) of g-level required for nominal functioning of cells; 4. Comparisons of magnetic levitation model to other models such as RWV, hind limb suspension, etc. and 5. Cellular response to reduced gravity levels of Moon and Mars. The paper will discuss experiments md modeling work to date in support of this project.

  6. Terrestrial Microgravity Model and Threshold Gravity Simulation sing Magnetic Levitation

    Science.gov (United States)

    Ramachandran, N.

    2005-01-01

    What is the threshold gravity (minimum gravity level) required for the nominal functioning of the human system? What dosage is required? Do human cell lines behave differently in microgravity in response to an external stimulus? The critical need for such a gravity simulator is emphasized by recent experiments on human epithelial cells and lymphocytes on the Space Shuttle clearly showing that cell growth and function are markedly different from those observed terrestrially. Those differences are also dramatic between cells grown in space and those in Rotating Wall Vessels (RWV), or NASA bioreactor often used to simulate microgravity, indicating that although morphological growth patterns (three dimensional growth) can be successiblly simulated using RWVs, cell function performance is not reproduced - a critical difference. If cell function is dramatically affected by gravity off-loading, then cell response to stimuli such as radiation, stress, etc. can be very different from terrestrial cell lines. Yet, we have no good gravity simulator for use in study of these phenomena. This represents a profound shortcoming for countermeasures research. We postulate that we can use magnetic levitation of cells and tissue, through the use of strong magnetic fields and field gradients, as a terrestrial microgravity model to study human cells. Specific objectives of the research are: 1. To develop a tried, tested and benchmarked terrestrial microgravity model for cell culture studies; 2. Gravity threshold determination; 3. Dosage (magnitude and duration) of g-level required for nominal functioning of cells; 4. Comparisons of magnetic levitation model to other models such as RWV, hind limb suspension, etc. and 5. Cellular response to reduced gravity levels of Moon and Mars.

  7. At the Digital Watershed: Terrestrial Television Broadcasting in Japan

    OpenAIRE

    Koga-Browes, Scott

    2012-01-01

    The switch to digital terrestrial broadcasting on 24 July 2011 marked a watershed for the broadcasting industry in Japan. Digitalisation is the single largest industry-wide event since the advent of alternative distribution technologies, satellite and cable, in the 1980s. Preparation for the switch to digital, known as chideji-ka, has put existing business arrangements under pressure and has led to a renewed focus on the future shape of the industry. There is increasing acknowledgement that c...

  8. Identifying and prioritising services in European terrestrial and freshwater ecosystems

    OpenAIRE

    Harrison, P. A.; Vandewalle, M; Sykes, M.T.; Berry, P. M. (Peter M.); Bugter, R.J.F.; Bello,; Feld, C.K.; Grandin, U.; Harrington, R.; Haslett, J.R.; Jongman, R. H. G.; Luck, G.W.; Martins da Silva, P.; Moora, M.; Settele, J.

    2010-01-01

    Ecosystems are multifunctional and provide humanity with a broad array of vital services. Effective management of services requires an improved evidence base, identifying the role of ecosystems in delivering multiple services, which can assist policy-makers in maintaining them. Here, information from the literature and scientific experts was used to systematically document the importance of services and identify trends in their use and status over time for the main terrestrial and freshwater ...

  9. Towards 250 m mapping of terrestrial primary productivity over Canada

    Science.gov (United States)

    Gonsamo, A.; Chen, J. M.

    2011-12-01

    Terrestrial ecosystems are an important part of the climate and global change systems. Their role in climate change and in the global carbon cycle is yet to be well understood. Dataset from satellite earth observation, coupled with numerical models provide the unique tools for monitoring the spatial and temporal dynamics of territorial carbon cycle. The Boreal Ecosystems Productivity Simulator (BEPS) is a remote sensing based approach to quantifying the terrestrial carbon cycle by that gross and net primary productivity (GPP and NPP) and terrestrial carbon sinks and sources expressed as net ecosystem productivity (NEP). We have currently implemented a scheme to map the GPP, NPP and NEP at 250 m for first time over Canada using BEPS model. This is supplemented by improved mapping of land cover and leaf area index (LAI) at 250 m over Canada from MODIS satellite dataset. The results from BEPS are compared with MODIS GPP product and further evaluated with estimated LAI from various sources to evaluate if the results capture the trend in amount of photosynthetic biomass distributions. Final evaluation will be to validate both BEPS and MODIS primary productivity estimates over the Fluxnet sites over Canada. The primary evaluation indicate that BEPS GPP estimates capture the over storey LAI variations over Canada very well compared to MODIS GPP estimates. There is a large offset of MODIS GPP, over-estimating the lower GPP value compared to BEPS GPP estimates. These variations will further be validated based on the measured values from the Fluxnet tower measurements over Canadian. The high resolution GPP (NPP) products at 250 m will further be used to scale the outputs between different ecosystem productivity models, in our case the Canadian carbon budget model of Canadian forest sector CBM-CFS) and the Integrated Terrestrial Ecosystem Carbon model (InTEC).

  10. Resource subsidies between stream and terrestrial ecosystems under global change

    Science.gov (United States)

    Larsen, Stefano; Muehlbauer, Jeffrey D.; Marti Roca, Maria Eugenia

    2016-01-01

    Streams and adjacent terrestrial ecosystems are characterized by permeable boundaries that are crossed by resource subsidies. Although the importance of these subsidies for riverine ecosystems is increasingly recognized, little is known about how they may be influenced by global environmental change. Drawing from available evidence, in this review we propose a conceptual framework to evaluate the effects of global change on the quality and spatiotemporal dynamics of stream–terrestrial subsidies. We illustrate how changes to hydrological and temperature regimes, atmospheric CO2 concentration, land use and the distribution of nonindigenous species can influence subsidy fluxes by affecting the biology and ecology of donor and recipient systems and the physical characteristics of stream–riparian boundaries. Climate-driven changes in the physiology and phenology of organisms with complex life cycles will influence their development time, body size and emergence patterns, with consequences for adjacent terrestrial consumers. Also, novel species interactions can modify subsidy dynamics via complex bottom-up and top-down effects. Given the seasonality and pulsed nature of subsidies, alterations of the temporal and spatial synchrony of resource availability to consumers across ecosystems are likely to result in ecological mismatches that can scale up from individual responses, to communities, to ecosystems. Similarly, altered hydrology, temperature, CO2 concentration and land use will modify the recruitment and quality of riparian vegetation, the timing of leaf abscission and the establishment of invasive riparian species. Along with morphological changes to stream–terrestrial boundaries, these will alter the use and fluxes of allochthonous subsidies associated with stream ecosystems. Future research should aim to understand how subsidy dynamics will be affected by key drivers of global change, including agricultural intensification, increasing water use and biotic

  11. Terrestrial Planet Formation: Constraining the Formation of Mercury

    Science.gov (United States)

    Lykawka, Patryk Sofia; Ito, Takashi

    2017-04-01

    How the four terrestrial planets of the solar system formed is one of the most fundamental questions in the planetary sciences. Particularly, the formation of Mercury remains poorly understood. We investigated terrestrial planet formation by performing 110 high-resolution N-body simulation runs using more than 100 embryos and 6000 disk planetesimals representing a primordial protoplanetary disk. To investigate the formation of Mercury, these simulations considered an inner region of the disk at 0.2-0.5 au (the Mercury region) and disks with and without mass enhancements beyond the ice line location, a IL, in the disk, where a IL = 1.5, 2.25, and 3.0 au were tested. Although Venus and Earth analogs (considering both orbits and masses) successfully formed in the majority of the runs, Mercury analogs were obtained in only nine runs. Mars analogs were also similarly scarce. Our Mercury analogs concentrated at orbits with a ˜ 0.27-0.34 au, relatively small eccentricities/inclinations, and median mass m ˜ 0.2 {M}\\oplus . In addition, we found that our Mercury analogs acquired most of their final masses from embryos/planetesimals initially located between 0.2 and ˜1-1.5 au within 10 Myr, while the remaining mass came from a wider region up to ˜3 au at later times. Although the ice line was negligible in the formation of planets located in the Mercury region, it enriched all terrestrial planets with water. Indeed, Mercury analogs showed a wide range of water mass fractions at the end of terrestrial planet formation.

  12. Function of Wildfire-Deposited Pyrogenic Carbon in Terrestrial Ecosystems

    OpenAIRE

    Melissa R. A. Pingree; DeLuca, Thomas H

    2017-01-01

    Fire is an important driver of change in most forest, savannah, and prairie ecosystems and fire-altered organic matter, or pyrogenic carbon (PyC), conveys numerous functions in soils of fire-maintained terrestrial ecosystems. Although an exceptional number of recent review articles and books have addressed agricultural soil application of charcoal or biochar, few reviews have addressed the functional role of naturally formed PyC in fire-maintained ecosystems. Recent advances in molecular spec...

  13. Natural and man-made terrestrial electromagnetic noise: an outlook

    OpenAIRE

    Bianchi, C.; Meloni, A.

    2007-01-01

    The terrestrial environment is continuously exposed to electromagnetic radiations which set up a «background» electromagnetic noise. Within the Non Ionizing Radiation band (NIR), i.e. for frequencies lower than 300 GHz, this background can have a natural or an artificial origin. Natural origins of electromagnetic radiations are generally atmospheric or cosmic while artificial origins are technological applications, power transmission, communications, etc. This paper briefly descri...

  14. Terrestrial Neutrons in West Zone II Building on Ito Campus

    OpenAIRE

    Naher, Kamrun; Ikeda, Nobuo; Fukuda, Hiroaki; Iwamoto, Hiroki; Fukui, Yoshinori; Koba, Yusuke; Imamura, Minoru; Uozumi, Yusuke

    2009-01-01

    Thermal and fast neutrons were measured inside the West Zone II building on Ito Campus for the assessment of terrestrial neutrons in a stand alone concrete building. Ratios of count rate of thermal neutrons to that of fast neutrons were almost constant inside the building. The contribution of fast neutrons across outside wall has been discussed. A simple method to estimate the neutron flux near the outside wall has been proposed.

  15. Terrestrial photovoltaic technologies - Recent progress in manufacturing R&D

    Energy Technology Data Exchange (ETDEWEB)

    Witt, C. E.; Surek, T.; Mitchell, R. L.; Symko-Davies, M.; Thomas, H. P.

    2000-05-15

    This paper describes photovoltaics (PV) as used for energy generation in terrestrial applications. A brief historical perspective of PV development is provided. Solar-to-electricity conversion efficiencies for various photovoltaic materials are presented, as well as expectations for further material improvements. Recent progress in reducing manufacturing costs through process R&D and product improvements are described. Applications that are most suitable for the different technologies are discussed. Finally, manufacturing capacities and current and projected module manufacturing costs are presented.

  16. Soil and vegetation parameter uncertainty on future terrestrial carbon sinks

    Science.gov (United States)

    Kothavala, Z.; Felzer, B. S.

    2013-12-01

    We examine the role of the terrestrial carbon cycle in a changing climate at the centennial scale using an intermediate complexity Earth system climate model that includes the effects of dynamic vegetation and the global carbon cycle. We present a series of ensemble simulations to evaluate the sensitivity of simulated terrestrial carbon sinks to three key model parameters: (a) The temperature dependence of soil carbon decomposition, (b) the upper temperature limits on the rate of photosynthesis, and (c) the nitrogen limitation of the maximum rate of carboxylation of Rubisco. We integrated the model in fully coupled mode for a 1200-year spin-up period, followed by a 300-year transient simulation starting at year 1800. Ensemble simulations were conducted varying each parameter individually and in combination with other variables. The results of the transient simulations show that terrestrial carbon uptake is very sensitive to the choice of model parameters. Changes in net primary productivity were most sensitive to the upper temperature limit on the rate of photosynthesis, which also had a dominant effect on overall land carbon trends; this is consistent with previous research that has shown the importance of climatic suppression of photosynthesis as a driver of carbon-climate feedbacks. Soil carbon generally decreased with increasing temperature, though the magnitude of this trend depends on both the net primary productivity changes and the temperature dependence of soil carbon decomposition. Vegetation carbon increased in some simulations, but this was not consistent across all configurations of model parameters. Comparing to global carbon budget observations, we identify the subset of model parameters which are consistent with observed carbon sinks; this serves to narrow considerably the future model projections of terrestrial carbon sink changes in comparison with the full model ensemble.

  17. Limno-terrestrial Tardigrada of the Nearctic Realm

    Directory of Open Access Journals (Sweden)

    Juliana G. HINTON

    2007-09-01

    Full Text Available We examined all available records of limno-terrestrial tardigrade distribution in the Nearctic realm (Greenland, Canada, Alaska, the continental United States of America, and northern Mexico, both to compare this fauna with other realms and to investigate distribution within North America. We included only those records in which tardigrades had been identified to species. Of 204 Nearctic limno-terrestrial tardigrade species, 38 were cosmopolitan, while 55 were unique to the Nearctic realm. The Nearctic tardigrade fauna is most similar to the Palearctic, with 135 species in common, 39 of which have not been reported elsewhere. The Nearctic realm shares 82 species with the Neotropical realm, only 10 which are not also Palearctic. These data are consistent with the geological history of the three realms, and indicate a distinction between Laurasian and Gondwanan tardigrade faunas. Although little is known about limno-terrestrial tardigrade distribution in much of North America, there are several excellent regional or local surveys. Many species are distributed widely throughout the continent, but 30.0% of Nearctic species have been reported from a single site. Cluster analysis of the fauna of 11 Nearctic regions shows that the Arctic and sub-Arctic fauna constitute a regional fauna distinct from the rest of the continent. Ecological analysis is hampered by inconsistent reporting of tardigrade substrate, though available data suggest little substrate specificity in terrestrial tardigrades. Most species are found in both mosses and lichens. Many are also present in soil and leaf litter, but few are found only in these substrates.

  18. Prediction of slug-to-annular flow pattern transition (SAT) for reducing the risk of gas lift instabilities and effective gas/liquid transport from low-pressure reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Toma, P. [Society of Petroleum Engineers, London (United Kingdom)]|[P.R. Toma Consulting Ltd., Bern (Germany); Vargas, E. [Alberta Univ., Edmonton, AB (Canada); Kuru, E. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[Alberta Univ., Edmonton, AB (Canada)

    2006-07-01

    It is common for gas, liquid hydrocarbons and water to be produced simultaneously through vertical wells in both onshore and offshore petroleum production systems. Water can be removed using artificial lift. In conventional gas lifting from low-pressure gas or coalbed reservoirs, flow instabilities can occur during the upward gas-liquid well transportation due to the slug to annular flow pattern transition (SAT). Conventional gas lifting involves large-diameter tubing. This paper presented the possibility of replacing gas lifting with gas-liquid flow in small-diameter tubes as a unique field production strategy. In particular, it described the effect of tubing diameter on the liquid production rate in gas lifted wells. Experimental and numerical modeling demonstrated the advantages and limitations of using small-diameter tubes for extreme gas lifting conditions. Replacing large-diameter tubing with small-diameter tubing was found to be better for unloading water and resuming production from gas wells with low reservoir pressure. The concept was proven using a specially designed experimental apparatus. 23 refs., 2 tabs., 12 figs., 1 appendix.

  19. Martian mud volcanism: Terrestrial analogs and implications for formational scenarios

    Science.gov (United States)

    Skinner, J.A.; Mazzini, A.

    2009-01-01

    The geology of Mars and the stratigraphic characteristics of its uppermost crust (mega-regolith) suggest that some of the pervasively-occurring pitted cones, mounds, and flows may have formed through processes akin to terrestrial mud volcanism. A comparison of terrestrial mud volcanism suggests that equivalent Martian processes likely required discrete sedimentary depocenters, volatile-enriched strata, buried rheological instabilities, and a mechanism of destabilization to initiate subsurface flow. We outline five formational scenarios whereby Martian mud volcanism might have occurred: (A) rapid deposition of sediments, (B) volcano-induced destabilization, (C) tectonic shortening, (D) long-term, load-induced subsidence, and (E) seismic shaking. We describe locations within and around the Martian northern plains that broadly fit the geological context of these scenarios and which contain mud volcano-like landforms. We compare terrestrial and Martian satellite images and examine the geological settings of mud volcano provinces on Earth in order to describe potential target areas for piercement structures on Mars. Our comparisons help to evaluate not only the role of water as a functional component of geological processes on Mars but also how Martian mud volcanoes could provide samples of otherwise inaccessible strata, some of which could contain astrobiological evidence.

  20. Fast Automatic Precision Tree Models from Terrestrial Laser Scanner Data

    Directory of Open Access Journals (Sweden)

    Mathias Disney

    2013-01-01

    Full Text Available This paper presents a new method for constructing quickly and automatically precision tree models from point clouds of the trunk and branches obtained by terrestrial laser scanning. The input of the method is a point cloud of a single tree scanned from multiple positions. The surface of the visible parts of the tree is robustly reconstructed by making a flexible cylinder model of the tree. The thorough quantitative model records also the topological branching structure. In this paper, every major step of the whole model reconstruction process, from the input to the finished model, is presented in detail. The model is constructed by a local approach in which the point cloud is covered with small sets corresponding to connected surface patches in the tree surface. The neighbor-relations and geometrical properties of these cover sets are used to reconstruct the details of the tree and, step by step, the whole tree. The point cloud and the sets are segmented into branches, after which the branches are modeled as collections of cylinders. From the model, the branching structure and size properties, such as volume and branch size distributions, for the whole tree or some of its parts, can be approximated. The approach is validated using both measured and modeled terrestrial laser scanner data from real trees and detailed 3D models. The results show that the method allows an easy extraction of various tree attributes from terrestrial or mobile laser scanning point clouds.