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Sample records for all-carbon quaternary centers

  1. Palladium-catalyzed asymmetric alkylation in the synthesis of cyclopentanoid and cycloheptanoid core structures bearing all-carbon quaternary stereocenters

    KAUST Repository

    Hong, Allen Y.

    2011-12-01

    General catalytic asymmetric routes toward cyclopentanoid and cycloheptanoid core structures embedded in numerous natural products have been developed. The central stereoselective transformation in our divergent strategies is the enantioselective decarboxylative alkylation of seven-membered β-ketoesters to form α-quaternary vinylogous esters. Recognition of the unusual reactivity of β-hydroxyketones resulting from the addition of hydride or organometallic reagents enabled divergent access to γ-quaternary acylcyclopentenes through a ring contraction pathway or γ-quaternary cycloheptenones through a carbonyl transposition pathway. Synthetic applications of these compounds were explored through the preparation of mono-, bi-, and tricyclic derivatives that can serve as valuable intermediates for the total synthesis of complex natural products. This work complements our previous work with cyclohexanoid systems.

  2. Palladium-Catalyzed Asymmetric Construction of Vicinal Tertiary and All-Carbon Quaternary Stereocenters by Allylation of β-Ketocarbonyls with Morita-Baylis-Hillman Adducts.

    Science.gov (United States)

    Liu, Jiawang; Han, Zhaobin; Wang, Xiaoming; Meng, Fanye; Wang, Zheng; Ding, Kuiling

    2017-04-24

    Palladium-catalyzed regio-, diastereo-, and enantioselective allylic alkylation of β-ketocarbonyls with Morita-Baylis-Hillman adducts has been developed using a spiroketal-based diphosphine (SKP) as the ligand, thus affording a range of densely functionalized products bearing vicinal tertiary and all-carbon quaternary stereodyad in high selectivities. The utility of the protocol was demonstrated by the facile synthesis of some complex molecules by simple product transformations. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Studies of the Formation of All-carbon Quaternary Centres, en route to Lyngbyatoxin A. A Comparison of Phenyl and 7-Substituted Indole Systems

    DEFF Research Database (Denmark)

    Tønder, Janne Ejrnæs; Hosseini, Masood; Ahrenst, Alex B.

    2004-01-01

    Copper mediated allylic substitutions and conjugate additions to geranyl, cinnamyl and allylic indole compounds have been investigated with the aim of finding a method for the creation of the all-carbon quaternary centre present in the natural product lyngbyatoxin A. Reaction conditions have been...... found giving a 68% S(N)2' selectivity in the copper mediated addition of PhMgBr to geranyl chloride, as well as 99% and 95% S(N)2' selectivity in the copper catalysed addition of EtMgBr to cinnamyl chloride and acetate, respectively. When the optimised reaction conditions were applied...... to the corresponding allylic compounds containing a 7-substituted indole moiety, the regioselectivity was reversed giving only the S(N)2 product. The allylic indole-containing substrates were also found to be unproductive in Pd- or Mo-catalysed S(N)2'-type substitution reactions. In related studies, copper catalysed...

  4. Palladium-Catalyzed Asymmetric Conjugate Addition of Arylboronic Acids to Five-, Six-, and Seven-Membered β-Substituted Cyclic Enones: Enantioselective Construction of All-Carbon Quaternary Stereocenters

    KAUST Repository

    Kikushima, Kotaro

    2011-05-11

    The first enantioselective Pd-catalyzed construction of all-carbon quaternary stereocenters via 1,4-addition of arylboronic acids to β-substituted cyclic enones is reported. Reaction of a wide range of arylboronic acids and cyclic enones using a catalyst prepared from Pd(OCOCF(3))(2) and a chiral pyridinooxazoline ligand yields enantioenriched products bearing benzylic stereocenters. Notably, this transformation is tolerant to air and moisture, providing a practical and operationally simple method of synthesizing enantioenriched all-carbon quaternary stereocenters.

  5. Ligand-Enabled γ-C–H Olefination and Carbonylation: Construction of β-Quaternary Carbon Centers

    Science.gov (United States)

    2015-01-01

    Monoselective γ-C–H olefination and carbonylation of aliphatic acids has been accomplished by using a combination of a quinoline-based ligand and a weakly coordinating amide directing group. The reaction provides a new route for constructing richly functionalized all-carbon quaternary carbon centers at the β-position of aliphatic acids. PMID:24666182

  6. Enantioselective synthesis of alkyne-substituted quaternary carbon stereogenic centers through NHC-Cu-catalyzed allylic substitution reactions with (i-Bu)2(alkynyl)aluminum reagents.

    Science.gov (United States)

    Dabrowski, Jennifer A; Gao, Fang; Hoveyda, Amir H

    2011-04-06

    A catalytic enantioselective method for the formation of alkyne-substituted all-carbon quaternary stereogenic centers is reported. Additions of alkynylaluminums to alkyl-, aryl-, carboxylic ester-, or silyl-substituted allylic phosphates are promoted by 1.0-5.0 mol % loadings of NHC-Cu complexes derived from air-stable and commercially available CuCl(2)·2H(2)O. The requisite Al-based reagents are prepared through treatment of the corresponding aryl-, heteroaryl-, alkyl-, or alkenyl-substituted terminal alkynes with diisobutylaluminum hydride in the presence of 5.0 mol % Et(3)N at ambient temperature. The desired 1,4-enynes are obtained in up to 98% yield and >99:1 enantiomeric ratio. Selected Au-catalyzed cyclizations involving the alkyne unit of the enantiomerically enriched products are presented as a demonstration of the method's utility in chemical synthesis. © 2011 American Chemical Society

  7. Enantioselective Synthesis of Alkyne-Substituted Quaternary Carbon Stereogenic Centers through NHC–Cu-Catalyzed Allylic Substitution Reactions with (i-Bu)2(Alkynyl)aluminum Reagents

    Science.gov (United States)

    Dabrowski, Jennifer A.; Gao, Fang; Hoveyda, Amir H.

    2011-01-01

    A catalytic enantioselective method for formation of alkyne-substituted all-carbon quaternary carbon stereogenic centers is reported. Additions of alkynylaluminums to alkyl-, aryl-, carboxylic ester-, or silyl-substituted allylic phosphates are promoted by 1.0–5.0 mol % of NHC–Cu complexes derived from air stable and commercially available CuCl2•2H2O. The requisite Al-based reagents are prepared through treatment of the corresponding aryl-, heteroaryl-, alkyl-, or alkenyl-substituted terminal alkynes with di-iso-butylaluminum hydride in the presence of 5.0 mol % Et3N at ambient temperature. The desired 1,4-enynes are obtained in up to >98% yield and >99:1 enantiomeric ratio. Selected Au-catalyzed cyclizations involving the alkyne unit of the enantiomerically enriched products are presented as a demonstration of the method’s utility in chemical synthesis. PMID:21384918

  8. Sr and Nd isotopic and trace element compositions of Quaternary volcanic centers of the Southern Andes

    Science.gov (United States)

    Futa, K.; Stern, C.R.

    1988-01-01

    Isotopic compositions of samples from six Quaternary volcanoes located in the northern and southern extremities of the Southern Volcanic Zone (SVZ, 33-46??S) of the Andes and from four centers in the Austral Volcanic Zone (AVZ, 49-54??S) range for 87Sr 86Sr from 0.70280 to 0.70591 and for 143Nd 144Nd from 0.51314 to 0.51255. The ranges are significantly greater than previously reported from the southern Andes but are different from the isotopic compositions of volcanoes in the central and northern Andes. Basalts and basaltic andesites from three centers just north of the Chile Rise-Trench triple junction have 87Sr 86Sr, 143Nd 144Nd, La Yb, Ba La, and Hf Lu that lie within the relatively restricted ranges of the basic magmas erupted from the volcanic centers as far north as 35??S in the SVZ of the Andes. The trace element and Sr and Nd isotopic characteristics of these magmas may be explained by source region contamination of subarc asthenosphere, with contaminants derived from subducted pelagic sediments and seawater-altered basalts by dehydration of subducted oceanic lithosphere. In the northern extremity of the SVZ between 33?? and 34??S, basaltic andesites and andesites have higher 87Sr 86Sr, Rb Cs, and Hf Lu, and lower 143Nd 144Nd than basalts and basaltic andesites erupted farther south in the SVZ, which suggests involvement of components derived from the continental crust. In the AVZ, the most primitive sample, high-Mg andesite from the southernmost volcanic center in the Andes (54??S) has Sr and Nd isotopic compositions and K Rb and Ba La similar to MORB. The high La Yb of this sample suggests formation by small degrees of partial melting of subducted MORB with garnet as a residue. Samples from centers farther north in the AVZ show a regionally regular northward increase in SiO2, K2O, Rb, Ba, Ba La, and 87Sr 86Sr and decrease in MgO, Sr, K Rb, Rb Cs, and 143Nd 144Nd, suggesting increasingly greater degrees of fractional crystallization and associated intra

  9. Regio- and stereoselective 1,2-dihydropyridine alkylation/addition sequence for the synthesis of piperidines with quaternary centers.

    Science.gov (United States)

    Duttwyler, Simon; Chen, Shuming; Lu, Colin; Mercado, Brandon Q; Bergman, Robert G; Ellman, Jonathan A

    2014-04-07

    The first example of C alkylation of 1,2-dihydropyridines with alkyl triflates and Michael acceptors was developed to introduce quaternary carbon centers with high regio- and diastereoselectivity. Hydride or carbon nucleophile addition to the resultant iminium ion also proceeded with high diastereoselectivity. Carbon nucleophile addition results in an unprecedented level of substitution to provide piperidine rings with adjacent tetrasubstituted carbon atoms. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Trends in Otolaryngology Consultation Patterns at an Academic Quaternary Care Center.

    Science.gov (United States)

    Choi, Kevin J; Kahmke, Russel R; Crowson, Matthew G; Puscas, Liana; Scher, Richard L; Cohen, Seth M

    2017-05-01

    The consultation patterns of an otolaryngology-head and neck surgery service have not previously been reported. The time, resources, and attention required to operate such a consultation service are unknown. To assess trends in otolaryngology-head and neck surgery consultations conducted in emergency departments (EDs) and inpatient services. A retrospective analysis was conducted of the medical records of patients at a quaternary care center receiving inpatient otolaryngology consultations from January 1 to December 31, 2014. Clinical evaluation and bedside and operative procedures performed by the otolaryngology-head and neck surgery service. Demographics, reason for consultation, diagnosis, bedside procedures, operative interventions, and admission variables. A total of 1491 consultations were completed for adult (1091 [73.2%]; 854 men and 637 women; mean [SD] age 50.3 [19.3] years) and pediatric (400 [26.8%]; 232 boys and 168 girls; mean [SD] age, 4.0 [5.2] years) patients. Of the 1491 consultations, 766 (51.4%) originated from inpatient teams vs 725 (48.6%) from the ED. A total of 995 of all consultations (66.7%) resulted in a bedside procedure, and 243 (16.3%) required operative intervention. Consultations regarding airway evaluation (362 [47.3%] vs 143 [19.7%]), management of epistaxis (78 [10.2%] vs 33 [4.6%]), and rhinologic evaluation (79 [10.3%] vs 18 [2.5%]) were more frequent from inpatient teams than from the ED. Consultations regarding management of head and neck infections (162 [22.3%] vs 32 [4.2%]), facial trauma (235 [32.4%] vs 16 [2.1%]), and postoperative complications (73 [10.1%] vs 2 [0.3%]) were more frequent in the ED. Of the 725 consultations performed in the ED, 212 patients (29.2%) required hospitalization. The consultation volume of an otolaryngology-head and neck surgery service requires significant time and resources. Consultations are most often for rhinologic or laryngologic issues and are reflective of the clinical setting in which

  11. Novel hollow all-carbon structures.

    Science.gov (United States)

    Sundholm, Dage; Wirz, Lukas N; Schwerdtfeger, Peter

    2015-10-14

    A new family of cavernous all-carbon structures is proposed. These molecular cage structures are constructed by edge subdivisions and leapfrog transformations from cubic polyhedra or their duals. The obtained structures were then optimized at the density functional level. These hollow carbon structures represent a new class of carbon allotropes which could lead to many interesting applications.

  12. γ'-Selective Functionalization of Cyclic Enones: Construction of a Chiral Quaternary Carbon Center by [4+2] Cycloaddition/Retro-Mannich Reaction with 3-Substituted Maleimides.

    Science.gov (United States)

    Zou, Chuncheng; Zeng, Chuikun; Liu, Zhen; Lu, Min; Sun, Xiaohua; Ye, Jinxing

    2016-11-07

    The first example of organocatalyzed γ'-selective functionalization of cyclic enones with 3-substituted maleimides results in the stereoselective construction quaternary carbon center is presented. The reactions provided γ'-functionalized cyclic enones and β-functionalized cyclopentenones in good to excellent yields with excellent diastereo- and enantioselectivities. DFT calculations indicated that the reaction might proceed as a [4+2] cycloaddition/retro-Mannich reaction which could explain the unexpected product with a chiral quaternary carbon center and the excellent stereoselectivity. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. [Climate implications of terrestrial paleoclimate]. Quaternary Sciences Center, Desert Research Institute annual report, fiscal year 1994/1995

    International Nuclear Information System (INIS)

    Wigand, P.E.

    1995-01-01

    The objective of this study is to collect terrestrial climate indicators for paleoclimate synthesis. The paleobiotic and geomorphic records are being examined for the local and regional impact of past climates to assess Yucca Mountain's suitability as a high-level nuclear waste repository. In particular these data are being used to provide estimates of the timing, duration and extremes of past periods of moister climate for use in hydrological models of local and regional recharge that are being formulated by USGS and other hydrologists for the Yucca Mountain area. The project includes botanical, faunal, and geomorphic components that will be integrated to accomplish this goal. To this end personnel at the Quaternary Sciences Center of the Desert Research Institute in Reno, Nevada are conducting the following activities: Analyses of packrat middens; Analysis of pollen samples; and Determination of vegetation climate relationships

  14. Efficient and highly enantioselective formation of the all-carbon quaternary stereocentre of lyngbyatoxin A

    DEFF Research Database (Denmark)

    Vital, Paulo J.V.; Tanner, David

    2006-01-01

    Indole 25, an advanced intermediate in a projected enantioselective total synthesis of lyngbyatoxin A 1, was prepared from allylic alcohol 11 in 9 steps and >95% ee, key transformations being the enantiospecific rearrangement of vinyl epoxide 14 and the Hemetsberger-Knittel reaction of azide 24....

  15. Off-Hour Surgery Among Orthopedic Subspecialties at an Urban, Quaternary-Care, Level 1 Trauma Center.

    Science.gov (United States)

    Lans, Amanda; Janssen, Stein J; Ring, David

    2016-12-01

    We sought to determine and quantify which subspecialties of orthopedic surgeons are operating off hours in an urban, quaternary-care, level 1 trauma center. We used our clinical registry to identify 43,211 orthopedic surgeries performed between January 2008 and December 2011. Our outcome measures were the number and proportion of off-hour surgeries performed as well as the number and proportion of off-hours per subspecialty. The denominators were the total number of surgeries and the total number of surgical hours worked per subspecialty. Subspecialties-based on the primary surgeon who performed the surgery-were arthroplasty, foot and ankle, hand, pediatrics, shoulder, spine, sports, orthopedic trauma, and orthopedic oncology. A total of 2,431 (5.6%) surgeries were off-hours; the overall ratio of off-hour to on-hour surgeries was 1 to 17. There was a difference in the proportion of off-hour surgeries performed among orthopedic subspecialties: trauma (ratio, 1:5) and pediatric specialists (ratio, 1:5) had the lowest ratio, and shoulder (ratio, 1:152) and sports (ratio, 1:98) specialists the highest. The total number of surgical hours among all specialties was 59,026; of these hours, 3,833 (6.5%) were off-hour. The ratio of off-hour to on-hour surgical hours was 1 to 14. There was a difference in proportion of hours worked off-hour among orthopedic subspecialties; the ratios were greatest for trauma (1:5) and hand (1:5) specialists and the least for shoulder (1:157) and sports (1:92) specialists. Seven percent of hand surgery cases were off-hour, and 16% of the total surgical hours worked by hand surgeons were off-hour. In an urban, academic, level 1 trauma and microvascular replantation regional referral hospital, there is a large difference in off-hour surgical volume and duration among orthopedic subspecialties: trauma, pediatric, and hand surgeons performed more off-hour work than their colleagues, with hand and pediatric surgeons the most likely to be working at

  16. All-Carbon Electrodes for Flexible Solar Cells

    Directory of Open Access Journals (Sweden)

    Zexia Zhang

    2018-01-01

    Full Text Available Transparent electrodes based on carbon nanomaterials have recently emerged as new alternatives to indium tin oxide (ITO or noble metal in organic photovoltaics (OPVs due to their attractive advantages, such as long-term stability, environmental friendliness, high conductivity, and low cost. However, it is still a challenge to apply all-carbon electrodes in OPVs. Here, we report our efforts to develop all-carbon electrodes in organic solar cells fabricated with different carbon-based materials, including carbon nanotubes (CNTs and graphene films synthesized by chemical vapor deposition (CVD. Flexible and semitransparent solar cells with all-carbon electrodes are successfully fabricated. The best power conversion efficiency achieved for the devices with all-carbon electrodes is 0.63%, comparable to the reported performance of OPVs using pristine CVD graphene films as anodes on rigid substrates (glass. Moreover, the current densities of as-obtained devices are comparable to those assembled with all-carbon active layers and standard electrodes (e.g., ITO and metal, which indicates that the all-carbon electrodes made of CNT and graphene films are suitably effective for carrier collection and extraction. Our results present the feasibility and potential of applying all-carbon electrodes based on graphitic nanomaterials in next-generation carbon-based photovoltaics.

  17. All-Carbon Electrodes for Flexible Solar Cells

    OpenAIRE

    Zexia Zhang; Ruitao Lv; Yi Jia; Xin Gan; Hongwei Zhu; Feiyu Kang

    2018-01-01

    Transparent electrodes based on carbon nanomaterials have recently emerged as new alternatives to indium tin oxide (ITO) or noble metal in organic photovoltaics (OPVs) due to their attractive advantages, such as long-term stability, environmental friendliness, high conductivity, and low cost. However, it is still a challenge to apply all-carbon electrodes in OPVs. Here, we report our efforts to develop all-carbon electrodes in organic solar cells fabricated with different carbon-based materia...

  18. Petrographic and geochemical investigation of magma chamber processes beneath small Quaternary volcanic centers between Mt. Jefferson and Mt. Hood volcanoes, Cascade Range Volcanic Arc

    Science.gov (United States)

    Cunningham, E.; Cribb, J. W.

    2017-12-01

    The northern Oregon Cascade Range has been dominated by andesite to rhyodacite lavas at both Mt. Jefferson (Conrey, 1991) and at Mt. Hood (Cribb and Barton, 1996) during the Quaternary period. Eruptive sequences at both Mt. Hood and Mt. Jefferson have been attributed to open-system mama mixing (Kent et al., 2010) (Ferrell et al., 2015), and the narrow range of lavas erupted at both centers has been derived from repeated cycles of magma mixing-fractionation (Cribb and Barton, 1996). This research examines major and trace element geochemistry as well as the petrographic characteristics of Clear Lake Butte (CLB), Pinhead Butte (PB), and Olallie Butte (OB), all of which are located between Mt. Hood and Mt. Jefferson, and have ben active in the Quaternary period. The research investigates whether the same type of open-system magma mixing known to have occurred at Mt. Hood and Mt. Jefferson has also occurred at CLB, PB, or OB, or whether those systems were closed to mixing and dominated by fractional crystallization. One of the main goals of this project is to highlight the similarities and differences exhibited by neighboring magmatic systems of similar age, but different scale. Disequilibrium textures observed in thin sections from CLB, OB, and PB suggest open-system magma mixing is likely occurring beneath all three buttes. This petrographic evidence includes plagioclase and pyroxene zoning, embayed margins, sieving, and reaction rims. Major element oxide trends at all three buttes are consistent with fractional crystallization, but show narrow concentrations and non-overlapping compositions between PB, CLB, and OB. All three buttes are characterized by narrow ranges of incompatible and compatible trace element concentrations. CLB, PB, and OB all exhibit LREE enrichment and lack significant HFSE depletions, with PB exhibiting greatest enrichment in REE.

  19. Attempts to prepare an all-carbon indigoid system

    OpenAIRE

    Yildizhan, ?eref; Hopf, Henning; Jones, Peter G

    2015-01-01

    First attempts are described to prepare a precursor for an all-carbon analog of indigo, the tetracyclic triene 4. Starting from indan-2-one (9) the α-methylene ketone 13 was prepared. Upon subjecting this compound to a McMurry coupling reaction, it dimerized to the bis-indene derivative 17, rather than providing the tetramethyl derivative of 4, the hydrocarbon 14. In a second approach, indan-1-one (18) was dimerized to the conjugated enedione 21 through the bis-1-indene dimer 19. All attempts...

  20. Extraordinarily Stretchable All-Carbon Collaborative Nanoarchitectures for Epidermal Sensors

    KAUST Repository

    Cai, Yichen

    2017-06-16

    Multifunctional microelectronic components featuring large stretchability, high sensitivity, high signal-to-noise ratio (SNR), and broad sensing range have attracted a huge surge of interest with the fast developing epidermal electronic systems. Here, the epidermal sensors based on all-carbon collaborative percolation network are demonstrated, which consist 3D graphene foam and carbon nanotubes (CNTs) obtained by two-step chemical vapor deposition processes. The nanoscaled CNT networks largely enhance the stretchability and SNR of the 3D microarchitectural graphene foams, endowing the strain sensor with a gauge factor as high as 35, a wide reliable sensing range up to 85%, and excellent cyclic stability (>5000 cycles). The flexible and reversible strain sensor can be easily mounted on human skin as a wearable electronic device for real-time and high accuracy detecting of electrophysiological stimuli and even for acoustic vibration recognition. The rationally designed all-carbon nanoarchitectures are scalable, low cost, and promising in practical applications requiring extraordinary stretchability and ultrahigh SNRs.

  1. How to Reduce Head CT Orders in Children with Hydrocephalus Using the Lean Six Sigma Methodology: Experience at a Major Quaternary Care Academic Children's Center.

    Science.gov (United States)

    Tekes, A; Jackson, E M; Ogborn, J; Liang, S; Bledsoe, M; Durand, D J; Jallo, G; Huisman, T A G M

    2016-06-01

    Lean Six Sigma methodology is increasingly used to drive improvement in patient safety, quality of care, and cost-effectiveness throughout the US health care delivery system. To demonstrate our value as specialists, radiologists can combine lean methodologies along with imaging expertise to optimize imaging elements-of-care pathways. In this article, we describe a Lean Six Sigma project with the goal of reducing the relative use of pediatric head CTs in our population of patients with hydrocephalus by 50% within 6 months. We applied a Lean Six Sigma methodology using a multidisciplinary team at a quaternary care academic children's center. The existing baseline imaging practice for hydrocephalus was outlined in a Kaizen session, and potential interventions were discussed. An improved radiation-free workflow with ultrafast MR imaging was created. Baseline data were collected for 3 months by using the departmental radiology information system. Data collection continued postintervention and during the control phase (each for 3 months). The percentage of neuroimaging per technique (head CT, head ultrasound, ultrafast brain MR imaging, and routine brain MR imaging) was recorded during each phase. The improved workflow resulted in a 75% relative reduction in the percentage of hydrocephalus imaging performed by CT between the pre- and postintervention/control phases (Z-test, P = .0001). Our lean interventions in the pediatric hydrocephalus care pathway resulted in a significant reduction in head CT orders and increased use of ultrafast brain MR imaging. © 2016 by American Journal of Neuroradiology.

  2. Attempts to prepare an all-carbon indigoid system

    Directory of Open Access Journals (Sweden)

    Şeref Yildizhan

    2015-03-01

    Full Text Available First attempts are described to prepare a precursor for an all-carbon analog of indigo, the tetracyclic triene 4. Starting from indan-2-one (9 the α-methylene ketone 13 was prepared. Upon subjecting this compound to a McMurry coupling reaction, it dimerized to the bis-indene derivative 17, rather than providing the tetramethyl derivative of 4, the hydrocarbon 14. In a second approach, indan-1-one (18 was dimerized to the conjugated enedione 21 through the bis-1-indene dimer 19. All attempts to methylenate 21 failed, however. When 19 was treated with the Tebbe reagent, the dimer 23 was produced, presumably through a Cope reaction of the intermediately generated isomer 22. The bis-indene derivative 23 can be alkylated with 1,2-dibromoethane to produce a 1:1 mixture of the spiro compounds 24 and 25. Although 9 could be reductively dimerized to 30, the conversion of this olefin to 14 failed.

  3. Attempts to prepare an all-carbon indigoid system

    Science.gov (United States)

    Yildizhan, Şeref; Jones, Peter G

    2015-01-01

    Summary First attempts are described to prepare a precursor for an all-carbon analog of indigo, the tetracyclic triene 4. Starting from indan-2-one (9) the α-methylene ketone 13 was prepared. Upon subjecting this compound to a McMurry coupling reaction, it dimerized to the bis-indene derivative 17, rather than providing the tetramethyl derivative of 4, the hydrocarbon 14. In a second approach, indan-1-one (18) was dimerized to the conjugated enedione 21 through the bis-1-indene dimer 19. All attempts to methylenate 21 failed, however. When 19 was treated with the Tebbe reagent, the dimer 23 was produced, presumably through a Cope reaction of the intermediately generated isomer 22. The bis-indene derivative 23 can be alkylated with 1,2-dibromoethane to produce a 1:1 mixture of the spiro compounds 24 and 25. Although 9 could be reductively dimerized to 30, the conversion of this olefin to 14 failed. PMID:25977710

  4. All-Carbon Electrode Consisting of Carbon Nanotubes on Graphite Foil for Flexible Electrochemical Applications

    Directory of Open Access Journals (Sweden)

    Je-Hwang Ryu

    2014-03-01

    Full Text Available We demonstrate the fabrication of an all-carbon electrode by plasma-enhanced chemical vapor deposition for use in flexible electrochemical applications. The electrode is composed of vertically aligned carbon nanotubes that are grown directly on a flexible graphite foil. Being all-carbon, the simple fabrication process and the excellent electrochemical characteristics present an approach through which high-performance, highly-stable and cost-effective electrochemical applications can be achieved.

  5. All-carbon-based field effect transistors fabricated by aerosol jet printing on flexible substrates

    International Nuclear Information System (INIS)

    Liu, Rui; Shen, Fangping; Ding, Haiyan; Gu, Wen; Zhang, Ting; Lin, Jian; Cui, Zheng

    2013-01-01

    An all-carbon-based field effect transistor (FET) was fabricated on flexible polyethylene terephthalate substrates by the aerosol jet printing method described in this paper. Three different types of homogeneous conductive inks were made and then printed layer-by-layer to form the FET chips. The conducting-reduced graphene oxide was used as electrodes (source and drain) and channel, respectively. Graphene oxide was used as dielectrics while multi-walled carbon nanotubes acted as the gate electrode. The all-carbon-based FET shows a good mobility of 350 cm 2 (V s) –1 at a drain bias of −1 V. This simple and novel method explores a promising way to fabricate all-carbon-based, flexible and low-cost electronic devices. (paper)

  6. Second Quaternary dating workshop

    International Nuclear Information System (INIS)

    1999-01-01

    The second Quaternary dating methods workshop was held at Lucas Heights and sponsored by ANSTO and AINSE. Topics covered include, isotope and thermoluminescence dating, usage of accelerator and thermal ionisation mass spectrometry in environmental studies emphasizing on the methodologies used and sample preparation

  7. Second Quaternary dating workshop

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-01

    The second Quaternary dating methods workshop was held at Lucas Heights and sponsored by ANSTO and AINSE. Topics covered include, isotope and thermoluminescence dating, usage of accelerator and thermal ionisation mass spectrometry in environmental studies emphasizing on the methodologies used and sample preparation

  8. An All Ireland Quaternary Map

    Science.gov (United States)

    Roberson, Sam; Pellicer, Xavier

    2017-04-01

    Ireland has a rich history of Quaternary mapping. After 150 years a comprehensive map of Irish Quaternary deposits has yet to be published. The nearest equivalent is the BRITICE project, a database of glacial landforms. As a result knowledge of Quaternary deposits are often only localised. The absence of an All-Ireland Quaternary map is brought sharply into focus given that the next International Quaternary Congress will be held in Dublin in 2019. We present the All-Ireland Quaternary map at 1:500 000 scale. The amalgamation of Quaternary maps from Republic of Ireland and Northern Ireland is not a straightforward process, due to differences in mapped scale, lithological codes and polygon distribution. Data from the Geological Survey of Ireland, the Geological Survey of Northern Ireland and the BRITICE project are simplified to produce a seamless data set of 17 sediment types, 4 geomorphological features and a point data set of interglacial sites. Soil geochemistry and airborne radiometric data from the Tellus and Tellus Border projects are used to subdivide undifferentiated till deposits in Northern Ireland. Domains of geochemically similar till are identified and merged with existing till domains in the Republic of Ireland.

  9. Quaternary system of cesium halides

    International Nuclear Information System (INIS)

    Bukhalova, G.A.; Shegurova, G.A.; Yagub'yan, E.S.; Zaporozhets, E.G.

    1977-01-01

    The state diagram of the quaternary system consisting of fluorides, chlorides, bromides, and iodides of cesium has been studied by visual-polythermal, partially X-ray phase and thermographical analyses. The crystallization volume of the quaternary system involves the crystallization volume of cesium fluoride and the crystallization volume of the ternary solid solutions of the rest cesium halides. A quaternary nonvariant point corresponding to melting point 360 deg C appears on the crystallization surface which separates the cesium fluoride volume from the volume of the ternary solid solutions

  10. Late Quaternary seismic sequence stratigraphy of the Gulf of Kachchh, northwest of India

    Digital Repository Service at National Institute of Oceanography (India)

    Michael, L.; Rao, D.G.; Krishna, K.S.; Vora, K.H.

    to arid climates during lowered sea levels, around Last Glacial Maximum (centered approx. 18 ka). Access to unique sedimentary records of the Late Quaternary climates/sea level changes even of decadal scale can be retrieved by collecting sediments...

  11. High performance all-carbon composite transparent electrodes containing uniform carbon nanotube networks

    International Nuclear Information System (INIS)

    Yun, Hyung Duk; Kwak, Jinsung; Kim, Se-Yang; Seo, Han; Bang, In Cheol; Kim, Sung Youb; Kang, Seoktae; Kwon, Soon-Yong

    2016-01-01

    Indium tin oxide-free, flexible transparent electrodes (TEs) are crucial for the future commercialization of flexible and wearable electronics. While carbon-based TEs containing carbon nanotube (CNT) networks show promise, they usually exhibit poor dispersion properties, limiting their performance and practicality. In this study, we report a highly efficient and bending durable all-carbon composite TE (ac-TE) that employs uniform CNT networks on a monolayer graphene/polyethylene terephthalate (PET) substrate via a simple air spray deposition method. The air-sprayed CNT/graphene assembly was free-standing on solution, making a polymer-free transfer of carbon composites to target substrates possible. The excellent performance of the ac-TEs was attributed to the uniformly networked CNTs on the polycrystalline graphene with a well-controlled density, effectively bridging the line defects and filling the tears/voids or folds necessarily existing in the as-processed graphene. The sheet resistance of the ac-TEs was increased only 6% from its original value at a bending radius of 2.7 mm, while that of the pristine graphene/PET assembly increased 237%. Mechanical bending of the ac-TEs worsened the electrical performance by only ∼1.7% after 2000 bending cycles at a bending radius of 2.5 mm. Degradation of the performance by the bending was the result of line defects formation in the graphene, demonstrating the potential of the uniform CNT networks to achieve more efficient and flexible carbon-based TEs. Furthermore, the chemically-doped ac-TEs showed commercially suitable electronic and optical properties with much enhanced thermal stability, closer to practical TEs in flexible devices. - Highlights: • Highly efficient and bending durable all-carbon composite transparent electrodes (TEs) are designed. • The performance was strongly dependent on morphology of CNT networks on graphene. • The mechanism relies on the defect reductions in graphene by uniform CNT coating

  12. Quaternary structure of methemoglobin

    International Nuclear Information System (INIS)

    Chevion, M.; Ilan, Y.A.; Samuni, A.; Navok, T.; Czapski, G.

    1979-01-01

    The pulse radiolysis of solutions of adult human methemoglobin was used to reduce a single heme iron within the protein tetramers. The valence hybrids thus formed were reacted with oxygen. Kinetics of the reactions were studied. The effects of pH and inositol hexaphosphate were examined. The kinetics of the ligation of oxygen to stripped valence hybrids showed a single phase behavior at the pH range 6.5 to 9. As the pH was lowered below 6.5, a second, slower phase became apparent. In the presence of inositol hexaphosphate, above pH 8, the kinetics of oxygen binding was of a single phase. As the pH was lowered, a transition to a second, slower phase was noticed. Below pH 7, the slower phase was the only detectable one. On this basis, it is concluded that human adult stripped methemoglobin resides in an R quarternary structure, while the presence of IHP stabilizes the T structure at pH below 7.5. This transition between the quaternary structures of methemoglobin cannot be accounted for by the switch between the high spin and the low spin states of the ferric iron. This switch of spin state takes place at pH>8.2

  13. All-carbon-based porous topological semimetal for Li-ion battery anode material.

    Science.gov (United States)

    Liu, Junyi; Wang, Shuo; Sun, Qiang

    2017-01-24

    Topological state of matter and lithium batteries are currently two hot topics in science and technology. Here we combine these two by exploring the possibility of using all-carbon-based porous topological semimetal for lithium battery anode material. Based on density-functional theory and the cluster-expansion method, we find that the recently identified topological semimetal bco-C 16 is a promising anode material with higher specific capacity (Li-C 4 ) than that of the commonly used graphite anode (Li-C 6 ), and Li ions in bco-C 16 exhibit a remarkable one-dimensional (1D) migration feature, and the ion diffusion channels are robust against the compressive and tensile strains during charging/discharging. Moreover, the energy barrier decreases with increasing Li insertion and can reach 0.019 eV at high Li ion concentration; the average voltage is as low as 0.23 V, and the volume change during the operation is comparable to that of graphite. These intriguing theoretical findings would stimulate experimental work on topological carbon materials.

  14. Flexible and Robust Thermoelectric Generators Based on All-Carbon Nanotube Yarn without Metal Electrodes.

    Science.gov (United States)

    Choi, Jaeyoo; Jung, Yeonsu; Yang, Seung Jae; Oh, Jun Young; Oh, Jinwoo; Jo, Kiyoung; Son, Jeong Gon; Moon, Seung Eon; Park, Chong Rae; Kim, Heesuk

    2017-08-22

    As practical interest in flexible/or wearable power-conversion devices increases, the demand for high-performance alternatives to thermoelectric (TE) generators based on brittle inorganic materials is growing. Herein, we propose a flexible and ultralight TE generator (TEG) based on carbon nanotube yarn (CNTY) with excellent TE performance. The as-prepared CNTY shows a superior electrical conductivity of 3147 S/cm due to increased longitudinal carrier mobility derived from a highly aligned structure. Our TEG is innovative in that the CNTY acts as multifunctions in the same device. The CNTY is alternatively doped into n- and p-types using polyethylenimine and FeCl 3 , respectively. The highly conductive CNTY between the doped regions is used as electrodes to minimize the circuit resistance, thereby forming an all-carbon TEG without additional metal deposition. A flexible TEG based on 60 pairs of n- and p-doped CNTY shows the maximum power density of 10.85 and 697 μW/g at temperature differences of 5 and 40 K, respectively, which are the highest values among reported TEGs based on flexible materials. We believe that the strategy proposed here to improve the power density of flexible TEG by introducing highly aligned CNTY and designing a device without metal electrodes shows great potential for the flexible/or wearable power-conversion devices.

  15. Nitrogen-doped carbon dots decorated on graphene: a novel all-carbon hybrid electrocatalyst for enhanced oxygen reduction reaction.

    Science.gov (United States)

    Hu, Chao; Yu, Chang; Li, Mingyu; Wang, Xiuna; Dong, Qiang; Wang, Gang; Qiu, Jieshan

    2015-02-25

    An all-carbon hybrid, composed of coal-based nitrogen-doped carbon dots decorated on graphene, was prepared via hydrothermal treatment. The hybrid possesses comparable electrocatalytic activity, better durability and methanol tolerance than those of the commercial Pt-based electrocatalysts for oxygen reduction reaction, indicative of its great potential in fuel cells.

  16. Designing Novel Quaternary Quantum Reversible Subtractor Circuits

    Science.gov (United States)

    Haghparast, Majid; Monfared, Asma Taheri

    2018-01-01

    Reversible logic synthesis is an important area of current research because of its ability to reduce energy dissipation. In recent years, multiple valued logic has received great attention due to its ability to reduce the width of the reversible circuit which is a main requirement in quantum technology. Subtractor circuits are between major components used in quantum computers. In this paper, we will discuss the design of a quaternary quantum reversible half subtractor circuit using quaternary 1-qudit, 2-qudit Muthukrishnan-Stroud and 3-qudit controlled gates and a 2-qudit Generalized quaternary gate. Then a design of a quaternary quantum reversible full subtractor circuit based on the quaternary half subtractor will be presenting. The designs shall then be evaluated in terms of quantum cost, constant input, garbage output, and hardware complexity. The proposed quaternary quantum reversible circuits are the first attempt in the designing of the aforementioned subtractor.

  17. Recent advances in quaternary geochronology

    International Nuclear Information System (INIS)

    Poupeau, G.

    1983-01-01

    Significant progress has occurred in quaternary geochronology. These include both (i) improvements in Fission Track and Thermoluminescence dating, as well as (ii) new technologies for short-lived (i.e. with half lives 6 yrs) radionuclide measurements as with the 14 C or uranium series desequilibrium dating, and finally (iii) the emergence of entirely new dating approches as the Electron Spin Resonnance Method. The aim of this paper is to review these progresses and the new areas they open geochronology for the past-miocene times. (author) [pt

  18. All-carbon vertical van der Waals heterostructures: Non-destructive functionalization of graphene for electronic applications

    OpenAIRE

    Woszczyna, Miroslaw; Winter, Andreas; Grothe, Miriam; Willunat, Annika; Wundrack, Stefan; Stosch, Rainer; Weimann, Thomas; Ahlers, Franz; Turchanin, Andrey

    2014-01-01

    We present a route to non-destructive functionalization of graphene via assembly of vertical all-carbon van der Waals heterostructures. To this end, we employ singlelayer graphene (SLG) sheets grown by low-pressure methane CVD on Cu foils and large-area dielectric ~1 nm thick amino-terminated carbon nanomembranes (NH2-CNMs) generated by electron-beam-induced crosslinking of aromatic self-assembled monolayers. We encapsulate SLG sheets on oxidized silicon wafers with NH2-CNMs via mechanical st...

  19. All-carbon multi-electrode array for real-time in vitro measurements of oxidizable neurotransmitters

    Science.gov (United States)

    Picollo, Federico; Battiato, Alfio; Bernardi, Ettore; Plaitano, Marilena; Franchino, Claudio; Gosso, Sara; Pasquarelli, Alberto; Carbone, Emilio; Olivero, Paolo; Carabelli, Valentina

    2016-02-01

    We report on the ion beam fabrication of all-carbon multi electrode arrays (MEAs) based on 16 graphitic micro-channels embedded in single-crystal diamond (SCD) substrates. The fabricated SCD-MEAs are systematically employed for the in vitro simultaneous amperometric detection of the secretory activity from populations of chromaffin cells, demonstrating a new sensing approach with respect to standard techniques. The biochemical stability and biocompatibility of the SCD-based device combined with the parallel recording of multi-electrodes array allow: i) a significant time saving in data collection during drug screening and/or pharmacological tests over a large number of cells, ii) the possibility of comparing altered cell functionality among cell populations, and iii) the repeatition of acquisition runs over many cycles with a fully non-toxic and chemically robust bio-sensitive substrate.

  20. Synthesis of enantioenriched γ-quaternary cycloheptenones using a combined allylic alkylation/Stork–Danheiser approach: preparation of mono-, bi-, and tricyclic systems

    KAUST Repository

    Bennett, Nathan B.

    2012-01-01

    A general method for the synthesis of β-substituted and unsubstituted cycloheptenones bearing enantioenriched all-carbon γ-quaternary stereocenters is reported. Hydride or organometallic addition to a seven-membered ring vinylogous ester followed by finely tuned quenching parameters achieves elimination to the corresponding cycloheptenone. The resulting enones are elaborated to bi- and tricyclic compounds with potential for the preparation of non-natural analogs and whose structures are embedded in a number of cycloheptanoid natural products.

  1. Late Quaternary changes in climate

    Energy Technology Data Exchange (ETDEWEB)

    Holmgren, K.; Karlen, W. [Stockholm Univ. (Sweden). Dept. of Physical Geography

    1998-12-01

    This review concerns the Quaternary climate with an emphasis on the last 200 000 years. The present state of art in this field is described and evaluated. The review builds on a thorough examination of classic and recent literature. General as well as detailed patterns in climate are described and the forcing factors and feed-back effects are discussed. Changes in climate occur on all time-scales. During more than 90% of the Quaternary period earth has experienced vast ice sheets, i.e. glaciations have been more normal for the period than the warm interglacial conditions we face today. Major changes in climate, such as the 100 000 years glacial/interglacial cycle, are forced by the Milankovitch three astronomical cycles. Because the cycles have different length climate changes on earth do not follow a simple pattern and it is not possible to find perfect analogues of a certain period in the geological record. Recent discoveries include the observation that major changes in climate seem to occur at the same time on both hemispheres, although the astronomical theory implies a time-lag between latitudes. This probably reflects the influence of feed-back effects within the climate system. Another recent finding of importance is the rapid fluctuations that seem to be a normal process. When earth warmed after the last glaciation temperature jumps of up to 10 deg C occurred within less than a decade and precipitation more than doubled within the same time. The forcing factors behind these rapid fluctuations are not well understood but are believed to be a result of major re-organisations in the oceanic circulation. Realizing that nature, on its own, can cause rapid climate changes of this magnitude put some perspective on the anthropogenic global warming debate, where it is believed that the release of greenhouse gases will result in a global warming of a few C. To understand the forcing behind natural rapid climate changes appears as important as to understand the role

  2. Late Quaternary changes in climate

    International Nuclear Information System (INIS)

    Holmgren, K.; Karlen, W.

    1998-12-01

    This review concerns the Quaternary climate with an emphasis on the last 200 000 years. The present state of art in this field is described and evaluated. The review builds on a thorough examination of classic and recent literature. General as well as detailed patterns in climate are described and the forcing factors and feed-back effects are discussed. Changes in climate occur on all time-scales. During more than 90% of the Quaternary period earth has experienced vast ice sheets, i.e. glaciations have been more normal for the period than the warm interglacial conditions we face today. Major changes in climate, such as the 100 000 years glacial/interglacial cycle, are forced by the Milankovitch three astronomical cycles. Because the cycles have different length climate changes on earth do not follow a simple pattern and it is not possible to find perfect analogues of a certain period in the geological record. Recent discoveries include the observation that major changes in climate seem to occur at the same time on both hemispheres, although the astronomical theory implies a time-lag between latitudes. This probably reflects the influence of feed-back effects within the climate system. Another recent finding of importance is the rapid fluctuations that seem to be a normal process. When earth warmed after the last glaciation temperature jumps of up to 10 deg C occurred within less than a decade and precipitation more than doubled within the same time. The forcing factors behind these rapid fluctuations are not well understood but are believed to be a result of major re-organisations in the oceanic circulation. Realizing that nature, on its own, can cause rapid climate changes of this magnitude put some perspective on the anthropogenic global warming debate, where it is believed that the release of greenhouse gases will result in a global warming of a few C. To understand the forcing behind natural rapid climate changes appears as important as to understand the role

  3. Quaternary glaciation of Mount Everest

    Science.gov (United States)

    Owen, Lewis A.; Robinson, Ruth; Benn, Douglas I.; Finkel, Robert C.; Davis, Nicole K.; Yi, Chaolu; Putkonen, Jaakko; Li, Dewen; Murray, Andrew S.

    2009-07-01

    The Quaternary glacial history of the Rongbuk valley on the northern slopes of Mount Everest is examined using field mapping, geomorphic and sedimentological methods, and optically stimulated luminescence (OSL) and 10Be terrestrial cosmogenic nuclide (TCN) dating. Six major sets of moraines are present representing significant glacier advances or still-stands. These date to >330 ka (Tingri moraine), >41 ka (Dzakar moraine), 24-27 ka (Jilong moraine), 14-17 ka (Rongbuk moraine), 8-2 ka (Samdupo moraines) and ˜1.6 ka (Xarlungnama moraine), and each is assigned to a distinct glacial stage named after the moraine. The Samdupo glacial stage is subdivided into Samdupo I (6.8-7.7 ka) and Samdupo II (˜2.4 ka). Comparison with OSL and TCN defined ages on moraines on the southern slopes of Mount Everest in the Khumbu Himal show that glaciations across the Everest massif were broadly synchronous. However, unlike the Khumbu Himal, no early Holocene glacier advance is recognized in the Rongbuk valley. This suggests that the Khumbu Himal may have received increased monsoon precipitation in the early Holocene to help increase positive glacier mass balances, while the Rongbuk valley was too sheltered to receive monsoon moisture during this time and glaciers could not advance. Comparison of equilibrium-line altitude depressions for glacial stages across Mount Everest reveals asymmetric patterns of glacier retreat that likely reflects greater glacier sensitivity to climate change on the northern slopes, possibly due to precipitation starvation.

  4. Voltage-Gated Transport of Nanoparticles across Free-Standing All-Carbon-Nanotube-Based Hollow-Fiber Membranes.

    Science.gov (United States)

    Wei, Gaoliang; Quan, Xie; Chen, Shuo; Fan, Xinfei; Yu, Hongtao; Zhao, Huimin

    2015-07-15

    Understanding the mechanism underlying controllable transmembrane transport observed in biological membranes benefits the development of next-generation separation membranes for a variety of important applications. In this work, on the basis of common structural features of cell membranes, a very simple biomimetic membrane system exhibiting gated transmembrane performance has been constructed using all-carbon-nanotube (CNT)-based hollow-fiber membranes. The conductive CNT membranes with hydrophobic pore channels can be positively or negatively charged and are consequently capable of regulating the transport of nanoparticles across their pore channels by their "opening" or "closing". The switch between penetration and rejection of nanoparticles through/by CNT membranes is of high efficiency and especially allows dynamic control. The underlying mechanism is that CNT pore channels with different polarities can prompt or prevent the formation of their noncovalent interactions with charged nanoparticles, resulting in their rejection or penetration by/through the CNT membranes. The theory about noncovalent interactions and charged pore channels may provide new insight into understanding the complicated ionically and bimolecularly gated transport across cell membranes and can contribute to many other important applications beyond the water purification and resource recovery demonstrated in this study.

  5. Clay mineral quaternary sediments mineralogy

    International Nuclear Information System (INIS)

    Karlsson, A.; Ayala, R.; Daziano, O.; Loyola, C.

    2007-01-01

    The subsidence is one of the geotechnical problems more important associated with Cordoba loess soils. The change of the mineral internal structure in the loess soils cause volume modification, that generate the potential danger of subsidence. The mineralogical evolution and the geotechnical behaviour in these soils are governed by the prevalent environmental hand lings in the region. A sequence of quaternary loess soils associated to a landscape with high carcavamiento has been studied. In this paper are examined the clay minerals and the calcium carbonates associated with the loess soils located in the superior basin of the Arroyo Tegua, Dto. Rio Cuarto, Prov. de Cordoba. The two-micron fraction was concentrated without previous destruction of cements and the determination of the mineral species has been carried out by means of X-Ray Diffraction methods. The clay minerals more abundant are the 2:1 non-expanded and rather crystallized ones. The 1:1non expanded mineral have disorderly structure and the 2:1 expanded are concentrated in the calcic horizons. The presence of palygoskite clay group was possible also to determine. The clay mineral composition in the studied sedimentary sequence is not homogeneous and the physical behavior of the different silts depends on the abundance and distribution of the clay minerals that carry. We can indicate that the clay minerals most unstable under humidity desiccation conditions are fireclay one and those of the palygorskite group. Recapitulating we can express that: vaterite is associated to more young silts and to a low alkaline environmental paleosoils genesis, but with a local CaCO3 supersaturation and alkalinity increase, vaterite transforms to calcite and also aragonite. (author)

  6. Quaternary Magmatism in the Cascades - Geologic Perspectives

    Science.gov (United States)

    Hildreth, Wes

    2007-01-01

    Foreward The Cascade magmatic arc is a belt of Quaternary volcanoes that extends 1,250 km from Lassen Peak in northern California to Meager Mountain in Canada, above the subduction zone where the Juan de Fuca Plate plunges beneath the North American Plate. This Professional Paper presents a synthesis of the entire volcanic arc, addressing all 2,300 known Quaternary volcanoes, not just the 30 or so visually prominent peaks that comprise the volcanic skyline. Study of Cascade volcanoes goes back to the geological explorers of the late 19th century and the seminal investigations of Howel Williams in the 1920s and 1930s. However, major progress and application of modern scientific methods and instrumentation began only in the 1970s with the advent of systematic geological, geophysical, and geochemical studies of the entire arc. Initial stimulus from the USGS Geothermal Research Program was enhanced by the USGS Volcano Hazards Program following the 1980 eruption of Mount St. Helens. Together, these two USGS Programs have provided more than three decades of stable funding, staffing, and analytical support. This Professional Paper summarizes the resultant USGS data sets and integrates them with the parallel contributions of other investigators. The product is based upon an all-encompassing and definitive geological database, including chemical and isotopic analyses to characterize the rocks and geochronology to provide the critical time constraints. Until now, this massive amount of data has not been summarized, and a systematic and uniform interpretation firmly grounded in geological fact has been lacking. Herein lies the primary utility of this Cascade volume. It not only will be the mandatory starting point for new workers, but also will provide essential geological context to broaden the perspectives of current investigators of specific Cascade volcanoes. Wes Hildreth's insightful understanding of volcanic processes and his uncompromising scientific integrity make him

  7. PRN 88-2: Clustering of Quaternary Ammonium Compounds

    Science.gov (United States)

    This Notice announces that EPA has clustered the Quaternary Ammonium Compounds into four groups for the purpose of testing chemicals to build a database that will support continued registration of the entire family of quaternary ammonium compounds

  8. Quaternary magnetic excursions recorded in marine sediments.

    Science.gov (United States)

    Channell, J. E. T.

    2017-12-01

    This year is the golden (50th) anniversary of the first documentation of a magnetic excursion, the Laschamp excursion in volcanics from the Chaine des Puys (Bonhommet and Babkine, 1967). The first recording of an excursion in sediments was from the Blake Outer Ridge (Smith and Foster, 1969). Magnetic excursions are directional aberrations of the geomagnetic field apparently involving short-lived reversal of the main dipole field. They have durations of a few kyrs, and are therefore rarely recorded in sediments with mean sedimentation rates control, is progressively strengthening our knowledge of the excursion inventory in the Quaternary, and enhancing the importance of excursions and RPI in Quaternary stratigraphy.

  9. Decomposition of Quaternary Signed-Graphic Matroids

    OpenAIRE

    Pitsoulis, Leonidas; Vretta, Eleni-Maria

    2015-01-01

    In this work we provide a decomposition theorem for the class of quaternary and non-binary signed-graphic matroids. This generalizes previous results for binary signed-graphic matroids and graphic matroids, and it provides the theoretical basis for a recognition algorithm.

  10. Climate predictors of late quaternary extinctions

    DEFF Research Database (Denmark)

    Nogués-Bravo, David; Ohlemüller, Ralf; Batra, Persaram

    2010-01-01

    Between 50,000 and 3,000 years before present (BP) 65% of mammal genera weighing over 44 kg went extinct, together with a lower proportion of small mammals. Why species went extinct in such large numbers is hotly debated. One of the arguments proposes that climate changes underlie Late Quaternary...

  11. Synthesis and antibacterial activity screening of quaternary ...

    Indian Academy of Sciences (India)

    A series of quaternary ammonium derivatives of triazolyl pyranochromen-2-ones have been synthesized and characterized; their antibacterial potential were investigated against two gram negative (Pseudomonas aeruginosa and Escherichia coli) and two gram positive bacterial strains (Bacillus cereus and Staphylococcus ...

  12. Palladium-Catalyzed Asymmetric Quaternary Stereocenter Formation

    NARCIS (Netherlands)

    Gottumukkala, Aditya L.; Matcha, Kiran; Lutz, Martin; de Vries, Johannes G.; Minnaard, Adriaan J.

    2012-01-01

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of beta,beta-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and

  13. Palladium-catalyzed asymmetric quaternary stereocenter formation

    NARCIS (Netherlands)

    Gottumukkala, A.L.; Matcha, K.; Lutz, M.|info:eu-repo/dai/nl/304828971; de Vries, J.G.; Minnaard, A.J.

    2012-01-01

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of β,β-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and provides

  14. Efficient cellulose solvent: quaternary ammonium chlorides.

    Science.gov (United States)

    Kostag, Marc; Liebert, Tim; El Seoud, Omar A; Heinze, Thomas

    2013-10-01

    Pure quaternary tetraalkylammonium chlorides with one long alkyl chain dissolved in various organic solvents constitute a new class of cellulose solvents. The electrolytes are prepared in high yields and purity by Menshutkin quaternization, an inexpensive and easy synthesis route. The pure molten tetraalkylammonium chlorides dissolve up to 15 wt% of cellulose. Cosolvents, including N,N-dimethylacetamide (DMA), may be added in large excess, leading to a system of decreased viscosity. Contrary to the well-established solvent DMA/LiCl, cellulose dissolves in DMA/quaternary ammonium chlorides without any pretreatment. Thus, the use of the new solvent avoids some disadvantages of DMA/LiCl and ionic liquids, the most extensively employed solvents for homogeneous cellulose chemistry. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Clocks for quaternary environments in Australia

    International Nuclear Information System (INIS)

    Tuniz, C.

    2002-01-01

    The Australian continent offers a variety of natural systems where records of the Earth's past environment have been stored, including sediment cores, tree rings, rock surfaces and corals. Rock varnish, mud-wasp nests and pack-rat middens provide alternative archives for vegetation and environmental change in arid areas, where continuous sedimentary sequences or trees are not available. Each of these media contain specific information on past climatic conditions but we must determine their chronology and decipher the relevant environmental parameters. Cosmogenic radionuclides, such as 14 C, 10 Be, 26 Al and 36 Cl, analysed by accelerator mass spectrometry, provide valuable radiometric clocks to establish an absolute time scale for the environmental events of the Quaternary. U-series, potassium-argon, argonargon and optically stimulated luminescence are other dating methods used in palaeoenvironmental studies. ANSTO supports the Quaternary science community in Australia providing the analysis of long-lived radionuclides: some significant projects from this program will be illustrated. (author)

  16. Energy consumption maps for quaternary distillation sequences

    DEFF Research Database (Denmark)

    Gomez-Castro, F.I.; Ramírez-Vallejo, N.E.; Segovia-Hernandez, J.G.

    2016-01-01

    be generated for the separation of multicomponent mixtures. This fact is an advantage, since a wide portfolio of alternatives can be used to separate a specific mixture; however, this is also a disadvantage since a lot of alternatives must be explored in order to find the optimal one. The optimal configuration...... of the solutions space. For the separation of ternary mixtures, Tedder and Rudd (1978) presented a composition map for which thermally coupled systems allowed energy savings. However, the scenario is different for quaternary mixtures, since no similar information is available. Therefore, in this work, energy...... consumption data for five feed compositions for a mixture near to ideality are presented. The quaternary sequences studied are: conventional direct (three columns), conventional indirect (three columns), thermally coupled direct (main column and two side rectifiers), and thermally coupled indirect (main...

  17. Radiocarbon dating for the Quaternary scientist

    International Nuclear Information System (INIS)

    Pilcher, J.R.

    1991-01-01

    The accuracy of many conventional and accelerator mass spectrometry (AMS) radiocarbon dates is not adequate for the sort of questions now being asked in Quaternary studies. The need for, and effects of, radiocarbon calibration are discussed and guide-lines offered for the selection of a laboratory. High precision laboratories and the use of wiggle matching will go a long way to answering the critical questions of rates of change and durations of events in the Holocene. (Author)

  18. Origin of bonebeds in Quaternary tank deposits

    Science.gov (United States)

    Araújo-Júnior, Hermínio Ismael de; Porpino, Kleberson de Oliveira; Bergqvist, Lílian Paglarelli

    2017-07-01

    Tank deposits are an exceptional type of fossiliferous deposit and bear a remarkably fossil record of the Pleistocene megafauna of South America, particularly of Brazil. The taphonomy of vertebrate remains preserved in this type of environmental context was clearly driven by climate, similarly to most of the Quaternary continental fossil record. The formation of the vertebrates fossil record in tank deposits was influenced by the climate seasonality typical of arid climate. The taphonomic history of most tank deposits is a consequence of this seasonality and, as a result, the paleoecological data preserved in their fossil assemblages is reliable with respect to paleobiological and paleoenvironmental settings of the Quaternary ecosystems of the Brazilian Intertropical Region (BIR). Other tank deposits experienced an unusual taphonomic history that, besides climate, was affected by recurrent events of reworking produced by the depositional agents dominant in the surrounding alluvial plains. The conclusions obtained here concerning the main taphonomic settings and formative processes that characterize fossil vertebrate assemblages of tank deposits will help further studies aimed to recover information on the paleoecology of Quaternary fauna collected in such deposits by allowing a better understanding of their time and spatial resolutions and other potential biases.

  19. DNA Barcoding through Quaternary LDPC Codes.

    Directory of Open Access Journals (Sweden)

    Elizabeth Tapia

    Full Text Available For many parallel applications of Next-Generation Sequencing (NGS technologies short barcodes able to accurately multiplex a large number of samples are demanded. To address these competitive requirements, the use of error-correcting codes is advised. Current barcoding systems are mostly built from short random error-correcting codes, a feature that strongly limits their multiplexing accuracy and experimental scalability. To overcome these problems on sequencing systems impaired by mismatch errors, the alternative use of binary BCH and pseudo-quaternary Hamming codes has been proposed. However, these codes either fail to provide a fine-scale with regard to size of barcodes (BCH or have intrinsic poor error correcting abilities (Hamming. Here, the design of barcodes from shortened binary BCH codes and quaternary Low Density Parity Check (LDPC codes is introduced. Simulation results show that although accurate barcoding systems of high multiplexing capacity can be obtained with any of these codes, using quaternary LDPC codes may be particularly advantageous due to the lower rates of read losses and undetected sample misidentification errors. Even at mismatch error rates of 10(-2 per base, 24-nt LDPC barcodes can be used to multiplex roughly 2000 samples with a sample misidentification error rate in the order of 10(-9 at the expense of a rate of read losses just in the order of 10(-6.

  20. Quaternary Geologic Map of Connecticut and Long Island Sound Basin

    Science.gov (United States)

    Stone, Janet Radway; Schafer, John P.; London, Elizabeth Haley; DiGiacomo-Cohen, Mary L.; Lewis, Ralph S.; Thompson, Woodrow B.

    2005-01-01

    The Quaternary geologic map (sheet 1) and explanatory figures and cross sections (sheet 2) portray the geologic features formed in Connecticut during the Quaternary Period, which includes the Pleistocene (glacial) and Holocene (postglacial) Epochs. The Quaternary Period has been a time of development of many details of the landscape and of all the surficial deposits. At least twice in the late Pleistocene, continental ice sheets swept across Connecticut. Their effects are of pervasive importance to the present occupants of the land. The Quaternary geologic map illustrates the geologic history and the distribution of depositional environments during the emplacement of glacial and postglacial surficial deposits and the landforms resulting from those events.

  1. Uranium-series dating of Quaternary deposits

    International Nuclear Information System (INIS)

    Schwarcz, H.; Gascoyne, M.

    1984-01-01

    In view of the interest in the problem of time scales in geomorphology it is fortunate that there exists a number of geochronometers applicable to the measurement of the age of such young deposits. This paper is specifically devoted to those which arise from the disequilibrium between the daughter isotopes of U-238 and U-235, and their respective parents. The authors describe applications to Quaternary continental deposits that can give information about climatic change (travertine, lacrustine limestones, pedogenic carbonates, detrinal sediments, volcanic rocks). (Auth.)

  2. Late quaternary Southern Indian Ocean circulation

    International Nuclear Information System (INIS)

    Howard, W.R.

    1985-01-01

    The climate of the Southern Indian Ocean is controled by the distinctive mid-to-high latitude oceanographic circulation features of the region. The oceanographic features have distinctive biotic signatures, which can be recognized in surface sediment furnaces. Studies of the Southern Indian Ocean down core time series indicated that oceanographic changes similar in magnitude to LGM-Modern shifts have been a regular, consistent and cyclic feature of the late Quaternary history of the Southern Indian Ocean. Oxygen isotopes and estimated sea-surface temperature records were used for this

  3. 21 CFR 172.165 - Quaternary ammonium chloride combination.

    Science.gov (United States)

    2010-04-01

    ... HUMAN CONSUMPTION Food Preservatives § 172.165 Quaternary ammonium chloride combination. The food... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Quaternary ammonium chloride combination. 172.165 Section 172.165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  4. Late Quaternary stratigraphic development in the lower Luni, Mahi ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 113; Issue 3. Late Quaternary stratigraphic development in the lower Luni, Mahi and Sabarmati river basins, western India. M Jain S K ... Keywords. Late Quaternary; lithofacies; luminescence chronology; stratigraphic correlation; fluvial response; climate change.

  5. Quaternary Ammonium Polyethyleneimine: Antibacterial Activity Ira

    International Nuclear Information System (INIS)

    Farber, Y.; Domb, A.G.; Golenser, J.; Beyth, N.; Weiss, E.I.

    2010-01-01

    Quaternary ammonium polyethyleneimine- (QA-PEI-) based nanoparticles were synthesized using two synthetic methods, reductive amination and N-alkylation. According to the first method, QA-PEI nanoparticles were synthesized by cross-linking with glutaraldehyde followed by reductive amination with octanal and further N-methylation with methyl iodide. The second method is based on crosslinking with dialkyl halide followed by N-alkylation with octyl halide and further N-methylation with methyl iodide. QA-PEI nanoparticles completely inhibited bacterial growth (>106 bacteria), including both Gram-positive, that is, Staphylococcus aureus at 80 μ/mL, and Gram-negative, that is, Escherichia coli at 320 μ/mL. Activity analysis revealed that the degree of alkylation and N-methylation of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl alkylated QA-PEI alkylated at 1 : 1 mole ratio (primary amine of PEI monomer units/alkylating agent). Also, cytotoxicity studies on MAT-LyLu and MBT cell lines were performed with QA-PEI nanoparticles. These findings confirm previous reports that poly cations bearing quaternary ammonium moieties inhibit bacterial growth in vitro and have a potential use as additives in medical devices which need antibacterial properties.

  6. Inferring and Using Protein Quaternary Structure Information from Crystallographic Data.

    Science.gov (United States)

    Dey, Sucharita; Levy, Emmanuel D

    2018-01-01

    A precise knowledge of the quaternary structure of proteins is essential to illuminate both their function and their evolution. The major part of our knowledge on quaternary structure is inferred from X-ray crystallography data, but this inference process is hard and error-prone. The difficulty lies in discriminating fortuitous protein contacts, which make up the lattice of protein crystals, from biological protein contacts that exist in the native cellular environment. Here, we review methods devised to discriminate between both types of contacts and describe resources for downloading protein quaternary structure information and identifying high-confidence quaternary structures. The use of high-confidence datasets of quaternary structures will be critical for the analysis of structural, functional, and evolutionary properties of proteins.

  7. The possibility of chemically inert, graphene-based all-carbon electronic devices with 0.8 eV gap.

    Science.gov (United States)

    Qi, Jing Shan; Huang, Jian Yu; Feng, Ji; Shi, Da Ning; Li, Ju

    2011-05-24

    Graphene is an interesting electronic material. However, flat monolayer graphene does not have significant gap in the electronic density of states, required for a large on-off ratio in logic applications. We propose here a novel device architecture, composed of self-folded carbon nanotube-graphene hybrids, which have been recently observed experimentally in Joule-heated graphene. These experiments demonstrated the feasibility of cutting, folding, and welding few-layer graphene in situ to form all-carbon nanostructures with complex topologies. The electronic gap of self-folded nanotubes can be combined with the semimetallicity of graphene electrodes to form a "metal-semiconductor-metal" junction. By ab initio calculations we demonstrate large energy gaps in the transmission spectra of such junctions, which preserve the intrinsic transport characteristics of the semiconducting nanotubes despite topologically necessary disinclinations at the flat graphene-curved nanotube interface. These all-carbon devices are proposed to be constructed by contact probe cutting and high-temperature annealing and, if produced, would be chemically stable at room temperature under normal gas environments.

  8. Late Quaternary vegetation-climate feedbacks

    Directory of Open Access Journals (Sweden)

    M. Claussen*

    2009-06-01

    Full Text Available Feedbacks between vegetation and other components of the climate system are discussed with respect to their influence on climate dynamics during the late Quaternary, i.e., the last glacial-interglacial cycles. When weighting current understanding based on interpretation of palaeobotanic and palaeoclimatic evidence by numerical climate system models, a number of arguments speak in favour of vegetation dynamics being an amplifier of orbital forcing. (a The vegetation-snow albedo feedback in synergy with the sea-ice albedo feedback tends to amplify Northern Hemisphere and global mean temperature changes. (b Variations in the extent of the largest desert on Earth, the Sahara, appear to be amplified by biogeophysical feedback. (c Biogeochemical feedbacks in the climate system in relation to vegetation migration are supposed to be negative on time scales of glacial cycles. However, with respect to changes in global mean temperature, they are presumably weaker than the positive biogeophysical feedbacks.

  9. Absolute age determination of quaternary faults

    International Nuclear Information System (INIS)

    Cheong, Chang Sik; Lee, Seok Hoon; Choi, Man Sik

    2000-03-01

    To constrain the age of neotectonic fault movement, Rb-Sr, K-Ar, U-series disequilibrium, C-14 and Be-10 methods were applied to the fault gouges, fracture infillings and sediments from the Malbang, Ipsil, Wonwonsa faults faults in the Ulsan fault zone, Yangsan fault in the Yeongdeog area and southeastern coastal area. Rb-Sr and K-Ar data imply that the fault movement of the Ulan fault zone initiated at around 30 Ma and preliminary dating result for the Yang san fault is around 70 Ma in the Yeongdeog area. K-Ar and U-series disequilibrium dating results for fracture infillings in the Ipsil fault are consistent with reported ESR ages. Radiocarbon ages of quaternary sediments from the Jeongjari area are discordant with stratigraphic sequence. Carbon isotope data indicate a difference of sedimentry environment for those samples. Be-10 dating results for the Suryum fault area are consistent with reported OSL results

  10. Absolute age determination of quaternary faults

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chang Sik; Lee, Seok Hoon; Choi, Man Sik [Korea Basic Science Institute, Seoul (Korea, Republic of)] (and others)

    2000-03-15

    To constrain the age of neotectonic fault movement, Rb-Sr, K-Ar, U-series disequilibrium, C-14 and Be-10 methods were applied to the fault gouges, fracture infillings and sediments from the Malbang, Ipsil, Wonwonsa faults faults in the Ulsan fault zone, Yangsan fault in the Yeongdeog area and southeastern coastal area. Rb-Sr and K-Ar data imply that the fault movement of the Ulan fault zone initiated at around 30 Ma and preliminary dating result for the Yang san fault is around 70 Ma in the Yeongdeog area. K-Ar and U-series disequilibrium dating results for fracture infillings in the Ipsil fault are consistent with reported ESR ages. Radiocarbon ages of quaternary sediments from the Jeongjari area are discordant with stratigraphic sequence. Carbon isotope data indicate a difference of sedimentry environment for those samples. Be-10 dating results for the Suryum fault area are consistent with reported OSL results.

  11. Hydration Structure of the Quaternary Ammonium Cations

    KAUST Repository

    Babiaczyk, Wojtek Iwo

    2010-11-25

    Two indicators of the hydropathicity of small solutes are introduced and tested by molecular dynamics simulations. These indicators are defined as probabilities of the orientation of water molecules\\' dipoles and hydrogen bond vectors, conditional on a generalized distance from the solute suitable for arbitrarily shaped molecules. Using conditional probabilities, it is possible to distinguish features of the distributions in close proximity of the solute. These regions contain the most significant information on the hydration structure but cannot be adequately represented by using, as is usually done, joint distance-angle probability densities. Our calculations show that using our indicators a relative hydropathicity scale for the interesting test set of the quaternary ammonium cations can be roughly determined. © 2010 American Chemical Society.

  12. Preparation of quaternary pyridinium salts as possible proton conductors

    Czech Academy of Sciences Publication Activity Database

    Urban, Jiří; Havlíček, D.; Krajbich, J.

    2015-01-01

    Roč. 69, č. 3 (2015), s. 448-455 ISSN 0366-6352 Institutional support: RVO:61388955 Keywords : quaternary pyridinium salts * synthesis * structural analysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.326, year: 2015

  13. Quantification of River Nile/Quaternary aquifer exchanges via ...

    Indian Academy of Sciences (India)

    www.ias.ac.in/article/fulltext/jess/125/08/1697-1711 ... Abstract. This study approach seeks to characterize the hydraulic interactions between the Nile and the Quaternary aquifer via riverbank filtration (RBF) in Abu Tieg area, Assuit Governorate.

  14. Quaternary phosphorites off the southeast coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Michard, A.; Naqvi, S.W.A.; Boettcher, M.E.; Krishnaswamy, R.; Thamban, M.; Natarajan, R.; Borole, D.V.

    the range expected for the oxic / suboxic zone but sulfur isotope ratios indicate suboxic conditions during phosphorite formation. These results imply that the benthic microbial mats thrived on the shallow shelf during the Quaternary low sea level conditions...

  15. Spectroscopic markers of the TR quaternary transition in human hemoglobin.

    Science.gov (United States)

    Schirò, Giorgio; Cammarata, Marco; Levantino, Matteo; Cupane, Antonio

    2005-04-01

    In this work, we use a sol-gel protocol to trap and compare the R and T quaternary states of both the deoxygenated (deoxyHb) and carbonmonoxide (HbCO) derivatives of human hemoglobin. The near infrared optical absorption band III and the infrared CO stretching band are used to detect the effect of quaternary structure on the spectral properties of deoxyHb and HbCO; comparison with myoglobin allows for an assessment of tertiary and quaternary contributions to the measured band shifts. The RT transition is shown to cause a blue shift of the band III by approximately 35 cm(-1) for deoxyHb and a red shift of the CO stretching band by only approximately 0.3 cm(-1) for HbCO. This clearly shows that quaternary structure changes are transmitted to the heme pocket and that effects on deoxyHb are much larger than on HbCO, at least as far as the band energies are concerned. Experiments performed in the ample temperature interval of 300-10K show that the above quaternary structure effects are "static" and do not influence the dynamic properties of the heme pocket, at least as probed by the temperature dependence of band III and of the CO stretching band. The availability of quaternary structure sensitive spectroscopic markers and the quantitative measurement of the quaternary structure contribution to band shifts will be of considerable help in the analysis of flash-photolysis experiments on hemoglobin. Moreover, it will enable one to characterize the dynamic properties of functionally relevant hemoglobin intermediates and to study the kinetics of both the T-->R and R-->T quaternary transitions through time-resolved spectroscopy.

  16. Mutagenicity of quaternary ammonium salts containing carbohydrate moieties

    Energy Technology Data Exchange (ETDEWEB)

    Dmochowska, Barbara [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Piosik, Jacek; Woziwodzka, Anna [Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk (Poland); Sikora, Karol; Wisniewski, Andrzej [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Wegrzyn, Grzegorz, E-mail: wegrzyn@biotech.univ.gda.pl [Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk (Poland)

    2011-10-15

    Highlights: {yields} A series of quaternary ammonium salts containing carbohydrate moieties, with configuration D-galacto, D-gluco and D-manno, was synthesized and characterized. {yields} The quaternary ammonium salts containing carbohydrate moieties revealed potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. {yields} The N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. {yields} We suggest that quaternary ammonium salts may be more hazardous than previously supposed. - Abstract: Quaternary ammonium salts are widely used in industrial, agricultural, healthcare and domestic applications. They are believed to be safe compounds, with little or no health hazard to humans. However, in this report, we demonstrate that a series of newly synthesized quaternary ammonium salts containing carbohydrate moieties reveal potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. D-Gluco- and D-galacto-derivatives were found to have a higher mutagenic potential than D-manno-derivatives. Among the former groups of compounds, the N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. These results suggest that the safety of quaternary ammonium salts may be lower than previously supposed, indicating a need for testing such compounds for their mutagenicity.

  17. Synthesis and anticoagulant activity of the quaternary ammonium chitosan sulfates.

    Science.gov (United States)

    Fan, Lihong; Wu, Penghui; Zhang, Jinrong; Gao, Song; Wang, Libo; Li, Mingjia; Sha, Mingming; Xie, Weiguo; Nie, Min

    2012-01-01

    Quaternary ammonium chitosan sulfates with diverse degrees of substitution (DS) ascribed to sulfate groups between 0.52 and 1.55 were synthesized by reacting quaternary ammonium chitosan with an uncommon sulfating agent (N(SO(3)Na)(3)) that was prepared from sodium bisulfite (NaHSO(3)) through reaction with sodium nitrite (NaNO(2)) in the aqueous system homogeneous. The structures of the derivatives were characterized by FTIR, (1)H NMR and (13)C NMR. The factors affecting DS of quaternary ammonium chitosan sulfates which included the molar ratio of NaNO(2) to quaternary ammonium chitosan, sulfated temperature, sulfated time and pH of sulfated reaction solution were investigated in detail. Its anticoagulation activity in vitro was determined by an activated partial thromboplastin time (APTT) assay, a thrombin time (TT) assay and a prothrombin time (PT) assay. Results of anticoagulation assays showed quaternary ammonium chitosan sulfates significantly prolonged APTT and TT, but not PT, and demonstrated that the introduction of sulfate groups into the quaternary ammonium chitosan structure improved its anticoagulant activity obviously. The study showed its anticoagulant properties strongly depended on its DS, concentration and molecular weight. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  18. Mutagenicity of quaternary ammonium salts containing carbohydrate moieties

    International Nuclear Information System (INIS)

    Dmochowska, Barbara; Piosik, Jacek; Woziwodzka, Anna; Sikora, Karol; Wisniewski, Andrzej; Wegrzyn, Grzegorz

    2011-01-01

    Highlights: → A series of quaternary ammonium salts containing carbohydrate moieties, with configuration D-galacto, D-gluco and D-manno, was synthesized and characterized. → The quaternary ammonium salts containing carbohydrate moieties revealed potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. → The N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. → We suggest that quaternary ammonium salts may be more hazardous than previously supposed. - Abstract: Quaternary ammonium salts are widely used in industrial, agricultural, healthcare and domestic applications. They are believed to be safe compounds, with little or no health hazard to humans. However, in this report, we demonstrate that a series of newly synthesized quaternary ammonium salts containing carbohydrate moieties reveal potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. D-Gluco- and D-galacto-derivatives were found to have a higher mutagenic potential than D-manno-derivatives. Among the former groups of compounds, the N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. These results suggest that the safety of quaternary ammonium salts may be lower than previously supposed, indicating a need for testing such compounds for their mutagenicity.

  19. A Quaternary fault database for central Asia

    Science.gov (United States)

    Mohadjer, Solmaz; Ehlers, Todd Alan; Bendick, Rebecca; Stübner, Konstanze; Strube, Timo

    2016-02-01

    Earthquakes represent the highest risk in terms of potential loss of lives and economic damage for central Asian countries. Knowledge of fault location and behavior is essential in calculating and mapping seismic hazard. Previous efforts in compiling fault information for central Asia have generated a large amount of data that are published in limited-access journals with no digital maps publicly available, or are limited in their description of important fault parameters such as slip rates. This study builds on previous work by improving access to fault information through a web-based interactive map and an online database with search capabilities that allow users to organize data by different fields. The data presented in this compilation include fault location, its geographic, seismic, and structural characteristics, short descriptions, narrative comments, and references to peer-reviewed publications. The interactive map displays 1196 fault traces and 34 000 earthquake locations on a shaded-relief map. The online database contains attributes for 123 faults mentioned in the literature, with Quaternary and geodetic slip rates reported for 38 and 26 faults respectively, and earthquake history reported for 39 faults. All data are accessible for viewing and download via http://www.geo.uni-tuebingen.de/faults/. This work has implications for seismic hazard studies in central Asia as it summarizes important fault parameters, and can reduce earthquake risk by enhancing public access to information. It also allows scientists and hazard assessment teams to identify structures and regions where data gaps exist and future investigations are needed.

  20. Brush Polymer of Donor-Accepter Dyads via Adduct Formation between Lewis Base Polymer Donor and All Carbon Lewis Acid Acceptor

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2017-09-01

    Full Text Available A synthetic method that taps into the facile Lewis base (LB→Lewis acid (LA adduct forming reaction between the semiconducting polymeric LB and all carbon LA C60 for the construction of covalently linked donor-acceptor dyads and brush polymer of dyads is reported. The polymeric LB is built on poly(3-hexylthiophene (P3HT macromers containing either an alkyl or vinyl imidazolium end group that can be readily converted into the N-heterocyclic carbene (NHC LB site, while the brush polymer architecture is conveniently constructed via radical polymerization of the macromer P3HT with the vinyl imidazolium chain end. Simply mixing of such donor polymeric LB with C60 rapidly creates linked P3HT-C60 dyads and brush polymer of dyads in which C60 is covalently linked to the NHC junction connecting the vinyl polymer main chain and the brush P3HT side chains. Thermal behaviors, electronic absorption and emission properties of the resulting P3HT-C60 dyads and brush polymer of dyads have been investigated. The results show that a change of the topology of the P3HT-C60 dyad from linear to brush architecture enhances the crystallinity and Tm of the P3HT domain and, along with other findings, they indicate that the brush polymer architecture of donor-acceptor domains provides a promising approach to improve performances of polymer-based solar cells.

  1. Quaternary Evolution of Karliova Triple Junction

    Science.gov (United States)

    Sançar, Taylan; Zabcı, Cengiz; Akyüz, H. Serdar

    2013-04-01

    The arguments to explain Quaternary evolution of Karlıova Triple Junction (KTJ) depends upon two different analogue models. The compressional type of Prandtl Cell Model (PCM) and 60 km wide shear zone with concomitant counter clockwise block rotation used to modelled for west and east of the KTJ respectively. The data for the model of west of the KTJ acquired by extensive field studies, and quantified geomorphic features. Compressional PCM put forward that behavior of slip lines controlled by boundary faults. But the model is not enough to explain slip distribution, age relation of them. At west of the KTJ boundary faults presented by eastern most segments of the North Anatolian Fault Zone (NAFZ) and the East Anatolian Fault Zone (EAFZ). Slip lines, however, presented by Bahçeli and Toklular faults. Both field studies and morphometric analyses undisputedly set forth that there are two different fault types between the NAFZ and EAFZ. The most strain loaded fault type, which are positioned near the NAFZ, start as a strike-slip fault and when it turn to SE its sense of motion change to oblique normal due to changing orientation of principal stress axes. The new orientation of stress axes exposed in the field as a special kind of caprock -cuesta-. The younger slip lines formed very close to junction point and accommodate less slip. Even though slip trajectories started from the boundary faults in compressional PCM, at the west of KTJ, right lateral trajectories more clearly formed close the NAFZ and left lateral trajectories, relatively less strain loaded fault type, are poorly formed close the EAFZ . We think that, this differences between KTJ and compressional PCM result from the distinction of velocity of boundary faults. East of the KTJ governed by completely different mechanism. The region controlled two main fault systems. The Varto Fault Zone (VFZ), the eastern branch of the KTJ, and Murat Fault (MF) delimited the region from north and south respectively. The

  2. Pseudoimpactites in anthropocenically overprinted quaternary sediments

    Science.gov (United States)

    Huber, Robert; Darga, Robert; Lauterbach, Hans

    2017-04-01

    Whereas typical anthropogenic materials such as plastics can easily be identified in the anthropocene record, other materials such as building materials or industrial waste often closely resemble natural rocks or minerals. Especially transported and weathered anthropocenic matter is hard to distinguish from natural rocks. Whereas most rock samples may easily be distinguished by visual inspection, definite identification of exotic and small sized matter is not always an easy exercise which has been shown during the controversial discussion on the cosmic origin of carbon spherules found in Younger Dryas sediments. Similarly, a variety of exotic materials and lithological phenomena reported from quaternary sediments in Upper Bavaria have been associated to a cosmic impact in the area. Findings of carbonatic regmaglypts, glass coated and fragmented rocks, glassy carbon or pumice like carbon have been proposed to represent impact related rocks, an hypothesis which has further been supported by findings of iron silicides and the postulated detection of nanodiamonds and Carbine. Many of these findings have been strongly doubted within the geoscientific community, however a systematic, independent investigation of these phenomena has not yet been conducted. We present the results of our examinations which have been carried out to critically test the impact related origin of the mentioned strange materials and rocks. We could identify some key sites and independently collected samples of several of the materials and analysed these thoroughly. We found that the majority of these impact related materials is of anthropogenic or biogenic origin, thus they are pseudoimpactites partly originating from old fireplaces and waste pits. The claimed cosmic origin of this matter is an illusion caused by the anthropocene overprint of the original sedimentary record.

  3. Quaternary evolution of the northern North Sea margin

    Science.gov (United States)

    Batchelor, C.; Ottesen, D.; Dowdeswell, J. A.

    2016-12-01

    At the start of the Quaternary, about 2.7 M yr ago, the bathymetry of the northern North Sea was dominated by the North Sea Basin, which has been infilled subsequently. The Norwegian Channel Ice Stream (NCIS) of the Scandinavian Ice Sheet (SIS) extended to the shelf break during several Mid to Late Quaternary full-glacial periods. However, little is known about Early Quaternary sedimentation on this margin. We use 2D and 3D seismic-reflection data to investigate the shelf and slope architecture and the patterns and processes of sedimentation in the northern North Sea through the Quaternary. The Early Quaternary infill of the northern North Sea Basin is shown to consist predominantly of glacigenic debris-flow deposits (GDFs) derived from an ice sheet that flowed perpendicular to the palaeo-shelf break during full-glacial periods, and contourites that were deposited by an ocean current that flowed parallel to the palaeo-shelf break during periods of reduced glaciation and active thermohaline circulation. This sequence of intercalated GDFs and contourites is suggested to record fluctuations in regional climate that are linked to the c. 41k glacial-interglacial cycles of the Early Quaternary. The Early Quaternary infilling of the northern North Sea Basin may have encouraged the initiation of a major ice stream by increasing the shelf width and reducing the water depth. Close to the onset of the Mid Quaternary, the south-western margin of the SIS was drained by an ice stream that was located partly beneath Måløy Plateau, 60 km east of the position of the NCIS during the Last Glacial Maximum. The changing architecture of the northern North Sea margin had an effect on the palaeo-oceanography of this region. The southward-flowing Norwegian Sea Bottom Water current is interpreted to have been directed into the concave, partially-closed northern North Sea Basin during the Early Quaternary, and to have been deflected progressively northwards as the basin became infilled.

  4. Electrostatic Layer-By-Layer Self-Assembled Graphene/Multi-Walled Carbon Nanotubes Hybrid Multilayers as Efficient 'All Carbon' Supercapacitors.

    Science.gov (United States)

    Gupta, Sanju; Heintzman, Eli; Price, Carson

    2016-05-01

    In this work, covalently bonded graphene/carbon nanotube (Gr/CNT) conjoined materials are fabricated as engineered three-dimensional hybrid multilayer supercapacitors for high-performance integrated electrochemical energy storage. Stable aqueous dispersion of polymer-modified graphene sheets are prepared in the presence of cationic poly(ethyleneimine), PEI (PEI-Gr) for sequential or electrostatic layer-by-layer (E-LBL) self-assembly with negatively charged acid-oxidized or functionalized multi-walled CNT (fMWCNT), forming (PEI-Gr/fMWCNT)n architecture as "all carbon" super-capacitor, where n = 1, 2, 4, 6, 9, 12 and 15. These films possess an interconnected network of mesoporous nanocarbon structure with well-defined interfaces allowing sufficient surface adsorption and faster ion transport due to short diffusion distances. They exhibit nearly rectangular cyclic voltammograms at an exceedingly high scan rate of 1 V/s with an average specific capacitance of -450 F g(-1) and specific energy density of 75.5 Wh kg(-1) based on electrode weight, measured at a current density of 0.3 A g(-1), comparable to that of Ni metal hydride battery and charged/discharged within a few seconds or a minute. This is attributed to the maximized synergistic effect of the highest specific surface areas by preventing re-aggregation of PEI-Gr or PEI-rGO via fMWCNT as spacers. We also determined relative contributions of the interfacial capacitance (C(dl)) and charge transfer (R(ct)) properties of the hybrids and investigated interfacial properties by SECM technique.

  5. Quaternary naltrexone reverses radiogenic and morphine-induced locomotor hyperactivity

    Energy Technology Data Exchange (ETDEWEB)

    Mickley, G.A.; Stevens, K.E.; Galbraith, J.A.; White, G.A.; Gibbs, G.L.

    1984-04-01

    The present study attempted to determine the relative role of the peripheral and central nervous system in the production of morphine-induced or radiation-induced locomotor hyperactivity of the mouse. Toward this end, we used a quaternary derivative of an opiate antagonist (naltrexone methobromide), which presumably does not cross the blood-brain barrier. Quaternary naltrexone was used to challenge the stereotypic locomotor response observed in these mice after either an i.p. injection of morphine or exposure to 1500 rads /sup 60/Co. The quaternary derivative of naltrexone reversed the locomotor hyperactivity normally observed in the C57BL/6J mouse after an injection of morphine. It also significantly attenuated radiation-induced locomotion. The data reported here support the hypothesis of endorphin involvement in radiation-induced and radiogenic behaviors. However, these conclusions are contingent upon further research which more fully evaluates naltrexone methobromide's capacity to cross the blood-brain barrier.

  6. Absolute age determination of quaternary fault and formation

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chang Sik; Lee, Kwang Sik; Choi, Man Sik [Korea Basic Science Institute, Seoul (Korea, Republic of)] (and others)

    2002-04-15

    The annual ('01-'01) objective of this project is to data the fault activity for the presumed quaternary fault zones to the western part of the Ulsam fault system and southeastern coastal area near the Wolseong Nuclear Power Plant. Rb-Sr, K-Ar, OSL, C-14 and U-series disequilibrium methods were applied to the fault rocks, organic matter and quaternary formations collected from the Pyeonghae, Bogyeongsa, Yugyeri, Byegkye, Gacheon-1 and Joil outcrops of the Yangsan fault system, the Baenaegol outcrop of the Moryang fault system, the Susyongji(Madong-2), Singye, Hwalseongri, Ipsil and Wonwonsa outcrops of the Ulsan fault system and from quaternary marine terraces (Oryoo and Kwangseong sites) in the southeastern coastal area. The experimental procedure of the OSL SAR protocol was reexamined to get more reliable dating results.

  7. Characterization of Quaternary and suspected Quaternary faults, Amargosa area, Nevada and California

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.E.; Crone, A.J.; Machette, M.N.; Bradley, L.A.; Diehl, S.F.

    1995-12-31

    This report presents the results of geologic studies that help define the Quaternary history of selected faults in the region around Yucca Mountain, Nevada. These results are relevant to the seismic-design basis of a potential nuclear waste repository at Yucca Mountain. The relevancy is based, in part, on a need for additional geologic data that became apparent in ongoing studies by S. Pezzopane (written commun., 1995) that resulted in the identification of 51 relevant and potentially relevant (see appendix A for definitions) individual and compound faults and fault zones in the 100-km-radius region around the Yucca Mountain site. These structures were divided into local and regional categories by Pezzopane (1995); this report deals with selected regional structures. In this introduction, the authors outline the scope and strategy of the studies and the tectonic environment of the studied structures.

  8. All-optical conversion scheme: Binary to quaternary and quaternary to binary number

    Science.gov (United States)

    Chattopadhyay, Tanay; Roy, Jitendra Nath

    2009-04-01

    To achieve the inherent parallelism in optics a suitable number system and efficient encoding/decoding scheme for handling the data are very much essential. Binary number is accepted as the best representing number system in almost all types of existing electronic computers. But, binary number (0 and 1) is insufficient in respect to the demand of the coming generation. Multi-valued logic (with radix >2) can be viewed as an alternative approach to solve many problems in transmission, storage and processing of large amount of information in digital signal processing. Here, in this paper all-optical scheme for the conversion of binary to quaternary number and vice versa have been proposed and described. Simulation has also been done. In this all-optical scheme the numbers are represented by different discrete polarized state of light.

  9. Characterization of Quaternary and suspected Quaternary faults, Amargosa area, Nevada and California

    International Nuclear Information System (INIS)

    Anderson, R.E.; Crone, A.J.; Machette, M.N.; Bradley, L.A.; Diehl, S.F.

    1995-01-01

    This report presents the results of geologic studies that help define the Quaternary history of selected faults in the region around Yucca Mountain, Nevada. These results are relevant to the seismic-design basis of a potential nuclear waste repository at Yucca Mountain. The relevancy is based, in part, on a need for additional geologic data that became apparent in ongoing studies by S. Pezzopane (written commun., 1995) that resulted in the identification of 51 relevant and potentially relevant (see appendix A for definitions) individual and compound faults and fault zones in the 100-km-radius region around the Yucca Mountain site. These structures were divided into local and regional categories by Pezzopane (1995); this report deals with selected regional structures. In this introduction, the authors outline the scope and strategy of the studies and the tectonic environment of the studied structures

  10. Electrochemical oxidation of quaternary ammonium electrolytes : Unexpected side reactions in organic electrochemistry

    NARCIS (Netherlands)

    Nouri Nigjeh, Eslam; de Vries, Marcel; Bruins, Andries P.; Bischoff, Rainer; Permentier, Hjalmar P.

    Quaternary ammonium salts are among the most widely used electrolytes in organic electrochemistry, but there is little known about their unwanted side oxidation reactions. We have, therefore, studied the constant potential oxidation products of quaternary ammonium electrolytes using mass

  11. Geomorphic expression of late Quaternary sea level changes along ...

    Indian Academy of Sciences (India)

    Geomorphic expression of land-sea interaction is preserved in the form of abandoned cliffs, marine terraces,shore platforms and marine notches along the southern Saurashtra coast. These features have been used to ascertain the magnitude of sea level changes during late Quaternary.Notch morphology and associated ...

  12. Minimal erosion of Arctic alpine topography during late Quaternary glaciation

    Science.gov (United States)

    Gjermundsen, Endre F.; Briner, Jason P.; Akçar, Naki; Foros, Jørn; Kubik, Peter W.; Salvigsen, Otto; Hormes, Anne

    2015-10-01

    The alpine topography observed in many mountainous regions is thought to have formed during repeated glaciations of the Quaternary period. Before this time, landscapes had much less relief. However, the spatial patterns and rates of Quaternary exhumation at high latitudes--where cold-based glaciers may protect rather than erode landscapes--are not fully quantified. Here we determine the exposure and burial histories of rock samples from eight summits of steep alpine peaks in northwestern Svalbard (79.5° N) using analyses of 10Be and 26Al concentrations. We find that the summits have been preserved for at least the past one million years. The antiquity of Svalbard’s alpine landscape is supported by the preservation of sediments older than one million years along a fjord valley, which suggests that both mountain summits and low-elevation landscapes experienced very low erosion rates over the past million years. Our findings support the establishment of northwestern Svalbard’s alpine topography during the early Quaternary. We suggest that, as the Quaternary ice age progressed, glacial erosion in the Arctic became inefficient and confined to ice streams, and high-relief alpine landscapes were preserved by minimally erosive glacier armour.

  13. Late Quaternary stratigraphic development in the lower Luni, Mahi ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    and architecture of the multistoried gravel sheets in the studied sections, it is suggested that older deposits are of pre-Quaternary age. This hypothesis implies the presence of a large hiatus .... ithic and medieval pottery; Mishra et al 1999). The stable isotopic composition of calcrete shows systematic temporal variations that ...

  14. Late Quaternary fine silt deposits of Jammu, NW Himalaya: Genesis ...

    Indian Academy of Sciences (India)

    The deposits termed as 'Potwar loessic silt' comprising sandy silt are essentially of late Quaternary age (75–18 ka) and are re-looked herein from the point of view of genesis and climatic significance. The sorting, skewness and kurtosis parameters of fine silts of Jammu suggest fluvial environment of the deposits wherein the ...

  15. Geo-Electric and Hydrogeochemical Mapping of Quaternary ...

    African Journals Online (AJOL)

    Michael Horsfall

    Geo-Electric and Hydrogeochemical Mapping of Quaternary Deposits at Orerokpe in the Western Niger Delta .... An Ertec model GPS instrument was used to position the wells as well as determine the approximate elevation of each well head. A contouring computer package was employed in generating the depth to water ...

  16. Integrating Quaternary science research in land management, restoration, and conservation

    Science.gov (United States)

    C.I. Millar; W.B. Woolfenden

    2001-01-01

    Most of us have come to expect that the general public will ignore the primary message of Quaternary science that change happens. A flurry, however, of recent media attention to 20th-century global warming and its anomalies from climates of the last millennium has brought climate science at least momentarily into popular focus. Similarly, public land-managing agencies...

  17. Characteristics and Classification of Soils on Quaternary Coversand ...

    African Journals Online (AJOL)

    Astudy was conducted to characterize and classify the soils on quaternary parent materials (Sangiwa, Sokoto, and Illela coversand) of Sokoto-Rima river basin area of Sokoto state. Areas covered with the coversand were identified using geologic map of the Sokoto-Rima basin followed by ground truthing. Soils from different ...

  18. Quaternary Glacial Mapping in Western Wisconsin Using Soil Survey Information

    Science.gov (United States)

    Oehlke, Betsy M.; Dolliver, Holly A. S.

    2011-01-01

    The majority of soils in the western Wisconsin have developed from glacial sediments deposited during the Quaternary Period (2.6 million years before present). In many regions, multiple advances and retreats have left a complex landscape of diverse glacial sediments and landforms. The soils that have developed on these deposits reflect the nature…

  19. Application of Analytic Geometry to Ternary and Quaternary Diagrams.

    Science.gov (United States)

    MacCarthy, Patrick

    1986-01-01

    Advantages of representing ternary and quaternary composition diagrams by means of rectangular coordinates were pointed out in a previous paper (EJ 288 693). A further advantage of that approach is that analytic geometry, based on rectangular coordinates, is directly applicable as demonstrated by the examples presented. (JN)

  20. Tectonic shortening and coeval volcanism during the Quaternary ...

    Indian Academy of Sciences (India)

    kbone Rang e. Figure 1. Location and shaded relief maps of NE Japan and distribution of Quaternary volcanoes (black triangles) and active faults (black lines) (Nakata and Imaizumi 2002). Solid triangles ... pilation of age data indicates that volcanoes rang- ing in age ...... tle wedge. Numerical simulations considering fluid.

  1. Electron paramagnetic resonance: a new method of quaternary dating

    International Nuclear Information System (INIS)

    Poupeau, G.; Rossi, A.; Universidade Federal Rural do Rio de Janeiro; Telles, M.; Danon, J.

    1984-01-01

    Significant progress has occurred in the last years in quaternary geochronology. One of this is the emergence of a new dating approach, the Electron Spin Resonance Method. The aim of this paper is to briefly review the method and discuss some aspects of the work at CBPF. (Author) [pt

  2. Occurrence of volcanic ash in the Quaternary alluvial deposits, lower ...

    Indian Academy of Sciences (India)

    This communication reports the occurrence of an ash layer intercalated within the late Quaternary alluvial succession of the Madhumati River, a tributary of the lower Narmada River. Petrographic, morphological and chemical details of glass shards and pumice fragments have formed the basis of this study. The ash has ...

  3. Quaternary ammonium salt N-(dodecyloxycarboxymethyl)- N,N,N ...

    Indian Academy of Sciences (India)

    2016-10-22

    Oct 22, 2016 ... viruses like HIV (human immunodeficiency virus) and HBV. (hepatitis B virus), but not nonenveloped viruses ( ..... To investigate whether quaternary ammonium salt IM impacts yeast growth in the presence of ... To investigate the influence of IM on plasma membrane lipid composition, the ergosterol and fatty ...

  4. Electron paramagnetic resonance: A new method of quaternary dating

    International Nuclear Information System (INIS)

    Poupeau, G.; Rossi, A.; Teles, M.M.; Danon, J.

    1984-01-01

    Significant progress has occurred in the last years in quaternary geochronology. One of this is the emergence of a new dating approach, the Electron Spin Resonance Method. The aim of this paper is to briefly review the method and discuss some aspects of the work at CBPF. (Author) [pt

  5. Fault control on patterns of Quaternary monogenetic vents in the ...

    African Journals Online (AJOL)

    Field and remote sensing data are used to examine the distribution of volcanism and fault geometry in the Ethiopian Rift between Omo-Chew Bahir rift and Tendaho graben during the Quaternary and evaluate their influence on the location and shape of individual vents as well as the development of alignments. The results ...

  6. Genetic footprints of demographic expansion in North America, but not Amazonia, during the Late Quaternary

    Science.gov (United States)

    Lessa, Enrique P.; Cook, Joseph A.; Patton, James L.

    2003-01-01

    The biotic consequences of climate change have attracted considerable attention. In particular, the “refugial debate” centers on the possible retraction of habitats to limited areas that may have served as refuges for many associated species, especially during glaciations of the Quaternary. One prediction of such scenarios is that populations must have experienced substantial growth accompanying climatic amelioration and the occupation of newly expanded habitats. We used coalescence theory to examine the genetic evidence, or lack thereof, for late Pleistocene refugia of boreal North American and tropical Amazonian mammals. We found substantial and concordant evidence of demographic expansion in North American mammals, particularly at higher latitudes. In contrast, small mammals from western Amazonia appear to have experienced limited or no demographic expansion after the Late Pleistocene. Thus, demographic responses to climate change can be tracked genetically and appear to vary substantially across the latitudinal gradient of biotic diversity. PMID:12913123

  7. Agarose gel shift assay reveals that calreticulin favors substrates with a quaternary structure in solution

    DEFF Research Database (Denmark)

    Boelt, Sanne Grundvad; Houen, Gunnar; Højrup, Peter

    2015-01-01

    Here we present an agarose gel shift assay that, in contrast to other electrophoresis approaches, is loaded in the center of the gel. This allows proteins to migrate in either direction according to their isoelectric points. Therefore, the presented assay enables a direct visualization, separation...... structure. It is also demonstrated that the agarose gel shift assay is useful in the study of other protein interactions and can be used as an alternative method to native polyacrylamide gel electrophoresis....... measure of interactions. Therefore, no interaction studies between calreticulin and substrates in solution have been investigated previously. The results presented here indicate that calreticulin has a preference for substrates with a quaternary structure and primarily β-sheets in their secondary...

  8. Facile regio- and stereoselective metal-free synthesis of all-carbon tetrasubstituted alkenes bearing a C(sp3)-F unit via dehydroxyfluorination of Morita-Baylis-Hillman (MBH) adducts.

    Science.gov (United States)

    Takizawa, Shinobu; Arteaga, Fernando Arteaga; Kishi, Kenta; Hirata, Shuichi; Sasai, Hiroaki

    2014-08-15

    Highly E-selective all-carbon tetrasubstituted alkenes with a C(sp(3))-F unit have been synthesized through a dehydroxyfluorination of Morita-Baylis-Hillman (MBH) adducts which can be readily prepared from α,β-unsaturated carbonyl compounds and α-keto esters. A variety of subsequent transformations afforded monofluoromethyl substituted heterocycles in high yields.

  9. Mapping a buried Quaternary valley and pre-Quaternary faults through seismic methods in Copenhagen, Denmark.

    Science.gov (United States)

    Martinez, Kerim; Alfredo Mendoza, Jose; Henrik, Olsen

    2010-05-01

    Limited knowledge of the subsurface geology motivates the use of geophysical techniques before large engineering projects are conducted. These applications are normally restricted to satisfy the project aims, like mapping the near surface sediments, unconsolidated rocks and/or geological structures that may affect the construction locally. However, the applications can also contribute to the general knowledge of the regional geology around the location of interest. This report highlights the mapping of a buried Quaternary valley and identification of regional faults by a reflection and refraction seismic survey performed in Copenhagen. A 13.9 Km seismic survey was carried out at Copenhagen city along six crooked lines in order to determine the velocity fields in the near subsurface segment of a planned metro line and reflection patterns in deeper levels. The aim of the survey was to collect information needed for designing the underground metro. In particular it was sought to map the interface between Quaternary sedimentary layers of clay, till and sand, and the underlying layers of Palaeogene limestone found between 7 and 40 m below the ground surface. The data acquisition was carried out using a 192 channels array, receiver groups with 5 m spacing and a Vibroseis as a source at 5 m spacing following a roll along technique to complete the survey spreads. The urban environment demanded extensive survey planning including traffic control, notifications to residents and a fluent coordination with municipal authorities in order to minimize disturbances and ensure data acquisition. The reflection data was processed under a conventional scheme and the refraction data was interpreted using a non-linear traveltime tomography algorithm. The reflection results indicate the presence of faults oriented NW-SE to NNW-SSE affecting the limestone sequences. The faults may be associated to the Sorgenfrei-Tornquist Zone at the transition between the Danish Basin and the Baltic

  10. Study on Quaternary ground siting of nuclear power plant, (1)

    International Nuclear Information System (INIS)

    Kokusho, Takaji; Nishi, Koichi; Honsho, Shizumitsu

    1991-01-01

    A seismic stability evaluation method for a nuclear power plant to be located on a Quaternary sandy/gravelly ground is discussed herein in terms of the geological and geotechnical survey, design earthquake motion evaluation and geotechnical seismic stability analyses. The geological and geotechnical exploration tunnel in the rock-foundation siting will be difficult in the Quaternary ground siting. Boring, geophysical surveys and soil samplings will play a major role in this case. The design earthquake input spectrum for this siting is proposed so as to take account the significant effect of longer period motion on the ground stability. Equivalent and non-linear analyses demonstrate the seismic stability of the foundation ground so long as the soil density is high. (author)

  11. The impact of Quaternary Ice Ages on mammalian evolution.

    Science.gov (United States)

    Lister, Adrian M

    2004-02-29

    The Quaternary was a time of extensive evolution among mammals. Most living species arose at this time, and many of them show adaptations to peculiarly Quaternary environments. The latter include continental northern steppe and tundra, and the formation of lakes and offshore islands. Although some species evolved fixed adaptations to specialist habitats, others developed flexible adaptations enabling them to inhabit broad niches and to survive major environmental changes. Adaptation to short-term (migratory and seasonal) habitat change probably played a part in pre-adapting mammal species to the longer-term cyclical changes of the Quaternary. Fossil evidence indicates that environmental changes of the order of thousands of years have been sufficient to produce subspeciation, but speciation has typically required one hundred thousand to a few hundred thousand years, although there are both shorter and longer exceptions. The persistence of taxa in environments imposing strong selective regimes may have been important in forcing major adaptive change. Individual Milankovitch cycles are not necessarily implicated in this process, but nor did they generally inhibit evolutionary change among mammals: many evolutionary divergences built over multiple climatic cycles. Deduction of speciation timing requires input from fossils and modern phenotypic and breeding data, to complement and constrain mitochondrial DNA coalescence dates which appear commonly to overestimate taxic divergence dates and durations of speciation. Migrational and evolutionary responses to climate change are not mutually exclusive but, on the contrary, may be synergistic. Finally, preliminary analysis suggests that faunal turnover, including an important element of speciation, was elevated in the Quaternary compared with the Neogene, at least in some biomes. Macroevolutionary species selection or sorting has apparently resulted in a modern mammalian fauna enriched with fast-reproducing and/or adaptively

  12. Significant differences in late Quaternary bedrock erosion and transport

    DEFF Research Database (Denmark)

    Andrews, John; Bjørk, Anders Anker; Eberl, Dennis

    2015-01-01

    in 10 cores from the two margins. On the East Greenland Shelf (EGS), late Quaternary samples have an average quartz weight per cent of 6.22.3 versus 12.83.9 from the West Greenland Shelf (WGS), and 12.024.8 versus 1.9 2.3wt% for pyroxene. K-means clustering indicated only 9% of the samples did not fit...

  13. Development of antibacterial quaternary ammonium silane coatings on polyurethane catheters

    Czech Academy of Sciences Publication Activity Database

    Zanini, S.; Polissi, A.; Maccagni, E.A.; Dell'Orto, E.C.; Liberatore, Chiara; Riccardi, C.

    2015-01-01

    Roč. 451, Aug (2015), 78-84 ISSN 0021-9797 R&D Projects: GA MŠk EE2.3.20.0143 Grant - others:OP VK 6(XE) CZ.1.07/2.3.00/20.0143 Institutional support: RVO:68378271 Keywords : plasma-induced graft-polymerization * acrylic acid * ATR/FTIR * AFM * quaternary ammonium silane * Escherichia coli Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.782, year: 2015

  14. Quaternary Heterogeneities: geospatial products for scientists, industry and decision making

    OpenAIRE

    Lee, J.; Cripps, C.; Kearsey, T.; Gow, H.; Finlayson, A.; Lee, K.; Entwisle, D.; Cartwright, C.; Hughes, L.

    2017-01-01

    Glaciation and permafrost has had a profound impact upon the UK landscape during the Quaternary. Their impact is most relevant within the ‘zone of human interaction’, the surface and near-surface parts of the geological record that humans utilise and exploit for societal and economic gain (e.g. infrastructure development, groundwater, energy, storage and minerals). However, whilst the broad range of glacial and periglacial processes that have affected the UK are known, their spatial influen...

  15. Late Quaternary extinctions: The promise of TAMS 14C dating

    International Nuclear Information System (INIS)

    Martin, P.S.

    1987-01-01

    In the last 30 000 years late Quaternary extinctions eliminated over two-thirds of the large land mammals of America and Australia and most of the endemic land vertebrates on oceanic islands. Specimens of extinct animals yielding too little organic material for measurement in decay counters are suitable for TAMS dating. Initial results support older evidence of an extinction chronology that was catastrophic regionally, transgressive globally, and linked to the spread of prehistoric people. (orig.)

  16. Isotopic and chemical investigations of quaternary aquifer in sinai peninsula

    International Nuclear Information System (INIS)

    Sadek, M.A.; Ahmed, M.A.; Awad, M.A.

    2001-01-01

    The present study has been conducted to investigate the renewal activity and mineralization potential of the quaternary aquifer in Sinai peninsula using environmental isotopes and hydrochemistry. The quaternary aquifer is vital for development processes as it has a wide extension and shallow water table. The total dissolved salts vary greatly from one location to another and range widely between 510-7060 mg/1, reflecting all categories from fresh to saline water. The change in salinity all over Sinai can be attributed to variations in the rate of evaporation. Leaching and dissolution of terrestrial salts during floods as well as the effects of sea spray and saline water intrusion. The main sources of groundwater recharge are the infiltration of Local precipitation and surface runoff as well as lateral flow through hydraulic connection with fractured aquifers. Snow melt also contributes to aquifer recharge in some areas in the central part of southern Sinai. The environmental stable isotopic contents of the ground water in the quaternary aquifer in Sinai reflect the isotopic composition of rain water from continental and east Mediterranean precipitation and monsonal air mass which comes from Indian ocean as well as the seepage of partly evaporated floodwater. The southern samples are more suitable for drinking and irrigation purposes due to its lower salinity and sodium hazard

  17. Anticholinesterase inhibitory activity of quaternary alkaloids from Tinospora crispa.

    Science.gov (United States)

    Yusoff, Mashitah; Hamid, Hazrulrizawati; Houghton, Peter

    2014-01-20

    Quaternary alkaloids are the major alkaloids isolated from Tinospora species. A previous study pointed to the necessary presence of quaternary nitrogens for strong acetylcholinesterase (AChE) inhibitory activity in such alkaloids. Repeated column chromatography of the vine of Tinospora crispa extract led to the isolation of one new protoberberine alkaloid, 4,13-dihydroxy-2,8,9-trimethoxydibenzo[a,g]quinolizinium (1), along with six known alkaloids-dihydrodiscretamine (2), columbamine (3), magnoflorine (4), N-formylannonaine (5), N-formylnornuciferine (6), and N-trans-feruloyltyramine (7). The seven compounds were isolated and structurally elucidated by spectroscopic analysis. Two known alkaloids, namely, dihydrodiscretamine and columbamine are reported for the first time for this plant. The compounds were tested for AChE inhibitory activity using Ellman's method. In the AChE inhibition assay, only columbamine (3) showed strong activity with IC50 48.1 µM. The structure-activity relationships derived from these results suggest that the quaternary nitrogen in the skeleton has some effect, but that a high degree of methoxylation is more important for acetylcholinesterase inhibition.

  18. 3n-Point Quaternary Shape Preserving Subdivision Schemes

    Directory of Open Access Journals (Sweden)

    MEHWISH BARI

    2017-07-01

    Full Text Available In this paper, an algorithm is defined to construct 3n-point quaternary approximating subdivision schemes which are useful to design different geometric objects in the field of geometric modeling. We are going to establish a family of approximating schemes because approximating scheme provide maximum smoothness as compare to the interpolating schemes. It is to be observed that the proposed schemes satisfying the basic sum rules with bell-shaped mask go up to the convergent subdivision schemes which preserve monotonicity. We analyze the shape-preserving properties such that convexity and concavity of proposed schemes. We also show that quaternary schemes associated to the certain refinable functions with dilation 4 have higher order shape preserving properties. We also calculated the polynomial reproduction of proposed quaternary approximating subdivision schemes. The proposed schemes have tension parameter, so by choosing different values of the tension parameter we can get different limit curves of initial control polygon. We show in the table form that the proposed schemes are better than the existing schemes by comparing them on the behalf of their support and continuity. The visual quality of proposed schemes is demonstrated by different snapshots.

  19. Phylogeography of Rhodiola kirilowii (Crassulaceae: a story of Miocene divergence and quaternary expansion.

    Directory of Open Access Journals (Sweden)

    Jian-Qiang Zhang

    Full Text Available The evolution and current distribution of the Sino-Tibetan flora have been greatly affected by historical geological events, such as the uplift of the Qinghai-Tibetan Plateau (QTP, and Quaternary climatic oscillations. Rhodiola kirilowii, a perennial herb with its distribution ranging from the southeastern QTP and the Hengduan Mountains (HM to adjacent northern China and central Asia, provides an excellent model to examine and disentangle the effect of both geological orogeny and climatic oscillation on the evolutionary history of species with such distribution patterns. We here conducted a phylogeographic study using sequences of two chloroplast fragments (trnL-F and trnS-G and internal transcribed spacers in 29 populations of R. kirilowii. A total of 25 plastid haplotypes and 12 ITS ribotypes were found. Molecular clock estimation revealed deep divergence between the central Asian populations and other populations from the HM and northern China; this split occurred ca. 2.84 million year ago. The majority of populations from the mountains of northern China were dominated by a single haplotype or ribotype, while populations of the HM harbored both high genetic diversity and high haplotype diversity. This distribution pattern indicates that HM was either a diversification center or a refugium for R. kirilowii during the Quaternary climatic oscillations. The present distribution of this species on mountains in northern China may have resulted from a rapid glacial population expansion from the HM. This expansion was confirmed by the mismatch distribution analysis and negative Tajima's D and Fu's FS values, and was dated to ca. 168 thousand years ago. High genetic diversity and population differentiation in both plastid and ITS sequences were revealed; these imply restricted gene flow between populations. A distinct isolation-by-distance pattern was suggested by the Mantel test. Our results show that in old lineages, populations may harbour

  20. Sharing post-AML consolidation supportive therapy with local centers reduces patient travel burden without compromising outcomes.

    Science.gov (United States)

    Hershenfeld, Samantha A; Maki, Kimberly; Rothfels, Lana; Murray, Cindy S; Nixon, Shannon; Schimmer, Aaron D; Doherty, Mary C

    2017-08-01

    Acute myeloid leukemia (AML) is frequently treated with induction and consolidation chemotherapy. Consolidation chemotherapy can be delivered on an ambulatory basis, requiring some patients to travel long distances for treatment at specialized centers. We developed a shared care model where patients receive consolidation chemotherapy at a quaternary center, but post-consolidation supportive care at local hospitals. To evaluate the impact of our model on patient travel and outcomes we conducted a retrospective analysis of AML and acute promyelocytic leukemia patients receiving consolidation over four years at our quaternary center. 73 patients received post-consolidation care locally, and 344 at the quaternary center. Gender, age and cytogenetic risk did not significantly differ between groups. Shared care patients saved mean round trip distance of 146.5km±99.6 and time of 96.7min±63.4 compared to travelling to quaternary center. There was no significant difference in overall survival between groups, and no increased hazard of death for shared care patients. 30, 60, and 90day survival from start of consolidation was 98.6%, 97.2%, and 95.9% for shared care and 98.8%, 97.1%, and 95.3% for quaternary center patients. Thus, a model utilizing regional partnerships for AML post-consolidation care reduces travel burden while maintaining safety. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Quaternary geology and waste disposal in South Norfolk, England

    Science.gov (United States)

    Gray, J. M.

    South Norfolk is dominated by the till plain of the Anglian Glaciation in eastern England, and therefore there are very few disused gravel pits and quarries suitable for the landfilling of municipal waste. Consequently, in May 1991, Norfolk County Council applied for planning permission to develop an above ground or 'landraise' waste disposal site at a disused U.S. World War II Airfield at Hardwick in South Norfolk. The proposal involved excavating a pit 2-4 m deep into the Lowestoft Till and overfilling it to create a hill of waste up to 10 m above the existing till plain. In general, leachate containment was to be achieved by utilising the relatively low permeability till on the floor of the site, but with reworking of the till around the site perimeter because of sand lenses in the upper part of the till. This paper examines three aspects of the proposal and the wider issues relating to Quaternary geology and waste disposal planning in South Norfolk: (i) the suitability of the till as a natural leachate containment system; (ii) the appropriateness of the landraise landform; and (iii) alternative sites. A Public Inquiry into the proposals was held in January/February 1993 and notification of refusal of planning permission was published in August 1993. Among the grounds for refusal were an inadequate knowledge of the site's geology and hydrogeology and the availability of alternative sites. The paper concludes by stressing that a knowledge of Quaternary geology is crucial to both the planning and design of landfill sites in areas of glacial/Quaternary sediments.

  2. Improved low temperature performance of lithium ion cells with quaternary carbonate-based electrolytes

    Science.gov (United States)

    Smart, M. C.; Ratnakumar, B. V.; Whitcanack, L. D.; Chin, K. B.; Surampudi, S.; Croft, H.; Tice, D.; Staniewicz, R.

    2002-01-01

    In order to enable future missions involving the exploration of the surface of Mars with Landers and Rovers, NASA desires long life, high energy density rechargeable batteries which can operate well at very low temperature (down to 40(deg)C). Lithium-ion technology has been identified as being the most promising chemistry, due to high gravimetric and volumetric energy densities, as well as, long life characteristics. However, the state-of-art (SOA) technology is not sufficient to meet the needs of many applications that require excellent low temperature capabilities. To further improve this technology, work at JF'L has been focused upon developing electrolytes that result in lithium-ion cells with wider temperature ranges of operation. These efforts have led to the identification of a number of ternary and quaternary, all carbonate-based electrolytes that have been demonstrated to result in improved low temperature performance in experimental three-electrode MCMB carbon/LiNio.sCoo.zOz cells. A number of electrochemical characterization techniques were performed on these cells (i.e., Tafel polarization measurements, linear polarization measurements, and electrochemical impedance spectroscopy (EIS)) to further enhance our understanding of the performance limitations at low temperature. The most promising electrolyte formulations, namely 1 .O M LiPF6EC+DEC+DMC+EMC (1 : 1: 1 :2 v/v) and 1 .O M LiPF6 EC+DEC+DMC+EMC (1 : 1 : 1 :3 v/v), were incorporated into SAFT prototype DD-size (9 Ahr) lithium- cells for evaluation. A number of electrical tests were performed on these cells, including rate characterization as a function of temperature, cycle life characterization at different temperatures, as well as, many mission specific characterization test to determine their viability to enable future missions to Mars. Excellent performance was observed with the prototype DD-size cells over a wide temperature range (-50 to 4OoC), with high specific energy being delivered at very

  3. Antimicrobial Polyethylene through Melt Compounding with Quaternary Ammonium Salts

    Directory of Open Access Journals (Sweden)

    Fernanda F. Rossetti

    2017-01-01

    Full Text Available Selected mono- and bicationic quats were compounded with polyethylene. The physicochemical surface properties, leaching behavior, and antibacterial activity of such modified samples were investigated. Contact angle measurements and fluorescein binding assays showed the presence of quaternary ammonium groups at the surface. After storing the samples in 50°C warm water for 30 days, several were still antimicrobially active. No correlation between the number of exposed N+ head groups after leaching and the antibacterial activity was observed. There is however a qualitative correlation of the antibacterial activity with the contact angles and surface concentrations of N+ before leaching/storing in warm water.

  4. Radiation-curable polymers bearing quaternary nitrogen groups

    International Nuclear Information System (INIS)

    Jones, G.D.

    1978-01-01

    Polymers, such as butadiene copolymers and isoprene copolymers, having pendant unsaturated tetra-aliphatic quaternary nitrogen moieties, such as those derived from acrylic esters and acrylamides are useful as water-soluble or inherently water-dispersible curable coatings such as protective and/or decorative coatings, paper coatings, textile fiber coatings, printing plates, photocurable imagable materials useful as photo-resists, lithographic plates, etc., and the like. Such coatings are curable with light, with high energy radiation and with heat in the presence of free radical catalysts to form insoluble, crosslinked coatings

  5. Quaternary Geologic Map of the Lake Superior 4° x 6° Quadrangle, United States and Canada

    Data.gov (United States)

    Department of the Interior — The Quaternary Geologic Map of the Lake Superior 4° x 6° Quadrangle was mapped as part of the Quaternary Geologic Atlas of the United States. The atlas was begun as...

  6. Quaternary association in β-prism I fold plant lectins: Insights from X ...

    Indian Academy of Sciences (India)

    [Sharma A and Vijayan M 2011 Quaternary association in β-prism I fold plant lectins: Insights from X-ray crystallography, modelling and molecular dynamics. J. Biosci. 36 793–808] DOI 10.1007/s12038-011-9166-2. 1. Introduction. The importance of quaternary association in the structure and function of proteins began to be ...

  7. All carbon nanotubes are not created equal

    International Nuclear Information System (INIS)

    Geohegan, David B.; Puretzky, Alexander A.; Rouleau, Christopher M.

    2010-01-01

    This chapter presents the various factors that enter into consideration when choosing the source of carbon nanotubes for a specific application. Carbon nanotubes are giant molecules made of pure carbon. They have captured the imagination of the scientific community by the unique structure that provides superior physical, chemical, and electrical properties. However, a surprisingly wide disparity exists between the intrinsic properties determined under ideal conditions and the properties that carbon nanotubes exhibit in real world situations. The lack of uniformity in carbon nanotube properties is likely to be the main obstacle holding back the development of carbon nanotube applications. This tutorial addresses the nonuniformity of carbon nanotube properties from the synthesis standpoint. This synthesis-related nonuniformity is on top of the intrinsic chirality distribution that gives the ∼1:2 ratio of metallic to semiconducting nanotubes. From the standpoint of carbon bonding chemistry the variation in the quality and reproducibility of carbon nanotube materials is not unexpected. It is an intrinsic feature that is related to the metastability of carbon structures. The extent to which this effect is manifested in carbon nanotube formation is governed by the type and the kinetics of the carbon nanotube synthesis reaction. Addressing this variation is critical if nanotubes are to live up to the potential already demonstrated by their phenomenal physical properties.

  8. Quaternary evolution of the Southern Apennines coastal plains: a review

    Directory of Open Access Journals (Sweden)

    Santangelo Nicoletta

    2017-02-01

    Full Text Available The Quaternary evolution of the main coastal basins located along the southwestern margin of the Southern Apennines has been reconstructed by integrating the huge amount of existing stratigraphical and geomorphological data. The information produced in the last twenty years has shed new light on the recent (late Middle Pleistocene to Present history of the Campanian and Sele plains or basins. During the early Quaternary, the analysed coastal basins originated as half-grabens in response to opening processes active since the late Tortonian in the southern Tyrrhenian back-arc basin. In some of these basins (e.g. the Campanian Plain, volcanism has also played an important role. In the inner sectors of the coastal basins, the complex interplay between block faulting, sedimentary inputs and glacioeustatic fluctuations gave rise to relative sea-level change and related coastline migrations, leading to the formation of the present-day coastal plains. In the Sele Plain basin, the construction of the present-day landscape mainly resulted from the substantial ceasing of subsidence in the final part of the Middle Pleistocene. Conversely, a strong contribution to the recent evolution of the Campanian Plain has been provided by abundant volcaniclastic aggradation, able to hinder the effect of the vertical motions that occurred in the last 100 ka.

  9. Quaternary (triphenyl-) phosphonium compounds: Environmental behavior and toxicity.

    Science.gov (United States)

    Brand, Simon; Schlüsener, Michael P; Albrecht, Dinah; Kunkel, Uwe; Strobel, Claudia; Grummt, Tamara; Ternes, Thomas A

    2018-06-01

    An analytical method based on high resolution mass spectrometry coupled with liquid chromatography (LC-HRMS) for 25 quaternary phosphonium compounds (QPCs) and derived phosphine oxides (POs) was developed and validated. To investigate the occurrence and fate of QPCs in the aquatic environment, water, suspended solids and sediments from the rivers Rhine and Elbe (upper and middle Elbe as well as tidal Elbe) were analyzed, as well as samples from tributaries bearing significant loads of QPCs. For the first time, the quaternary phosphonium compound tetrabutylphosphonium (Bu 4 P + ) was detected. In the river Elbe concentrations were determined of up to 4700 ng/L (surface water) and 1000 μg/kg (sediment), respectively. Analysis of a time series of suspended solids (2005-2015) showed that QPCs have been present in the Elbe and Rhine catchment for at least one decade, with partly rising tendency. A degradation experiment with Rhine sediment revealed that triphenylphosphonium compounds (R-Ph 3 P + ) and Bu 4 P + are persistent in contact with sediment and suspended solids and tend to sorb onto sediment particles. Toxicological studies (reactive oxygen species (ROS) after substance exposure, Ames test, Micronucleus test, determination of cytotoxicity) with selected QPCs confirmed that all of them exhibit cytotoxicity and some even genotoxic potential at elevated concentrations, which emphasizes the need for an emission regulation of these compounds. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Understanding the major transitions in Quaternary climate dynamics

    Science.gov (United States)

    Willeit, Matteo; Ganopolski, Andrey

    2017-04-01

    Climate dynamics over the past 3 million years was characterized by strong variability associated with glacial cycles and several distinct regime changes. The Pliocene-Pleistocene Transition (PPT), which happened around 2.7 million years ago, was characterized by the appearance of the large continental ice sheets over Northern Eurasia and North America. For two million years after the PPT climate variability was dominated by relatively symmetric 40 kyr cycles. At around 1 million years ago the dominant mode of climate variability experienced a relatively rapid transition from 40 kyr to strongly asymmetric 100 kyr cycles of larger amplitude (Mid-Pleistocene Transition). Additionally, during the past 800 kyr there are clear differences between the earlier and the later glacial cycles with the last five cycles characterized by larger magnitude of variability (Mid-Brunhes Event). Here, we use the Earth system model of intermediate complexity CLIMBER-2 to explore possible mechanisms that could explain these regime shifts. CLIMBER-2 incorporates all major components of the Earth system - atmosphere, ocean, land surface, northern hemisphere ice sheets, terrestrial biota and soil carbon, marine biogeochemistry and aeolian dust. The model was optimally tuned to reproduce climate, ice volume and CO2 variability over the last 400,000 years. Using the same model version, we performed a large set of simulations covering the entire Quaternary (3 million years) starting from identical initial conditions and using a parallelization in time technique which consists of starting the model at different times (every 100,000 years) and running each simulation for 500,000 years. The Earth's orbital variations are the only prescribed radiative forcing. Several sets of the Northern Hemisphere orography and sediment thickness representing different stages of landscape evolution during the Quaternary are prescribed as boundary conditions for the ice sheet model and volcanic CO2 outgassing is

  11. Quaternary Reorganization of North American Mid-continent Drainage Systems

    Science.gov (United States)

    Carson, E. C.; Rawling, J. E., III; Attig, J. W.; Bates, B. R.

    2013-12-01

    Identification of ancestral drainage systems in the North American mid-continent has been a topic of research and debate among geologists since the middle of the 19th Century. Over time our understanding of the significance of Quaternary glaciations in reshaping drainage patterns has grown. The ancestral Teays River, which drained large areas of the central Appalachians and flowed westward across Indiana and western Illinois, was dammed multiple times by Quaternary glaciers before finally being rerouted to the course of the modern central Ohio River. Similarly, the northward-flowing ancestral Pittsburgh River was dammed by pre-Illinoian glaciers; subsequent stream piracy converted this river system into the modern Allegheny, Monongahela and uppermost Ohio Rivers. Deposits and geomorphic features along the westward-flowing lower Wisconsin River indicate that the modern upper Mississippi River and Wisconsin River may have experienced a similar history of ice blockage, stream piracy, and radical rerouting. Coring into the Bridgeport strath terrace along the lower Wisconsin River reveals that the bedrock surface dips to the east, indicating the valley was cut by an eastward-flowing river. We believe the most likely scenario following this interpretation is that an ancestral river flowing along the modern upper Mississippi River valley made a sharp bend at Prairie du Chien, WI, and flowed eastward along the valley occupied by the modern lower Wisconsin River. This river, referred to here as the Wyalusing River, likely flowed northeastward into the Great Lakes (St. Lawrence) drainage until that path was blocked by ice advancing from the northwest. Subsequent stream piracy immediately south of the modern confluence of the Mississippi and Wisconsin Rivers rerouted these streams, converting them to the headwaters of the greater Mississippi drainage. The combined rerouting of these river systems into entirely different drainage basins necessitates significant fundamental

  12. Quaternary history and contemporary patterns in a currently expanding species

    Directory of Open Access Journals (Sweden)

    Rousselet Jérôme

    2009-09-01

    Full Text Available Abstract Background Quaternary climatic oscillations had dramatic effects on species evolution. In northern latitudes, populations had to survive the coldest periods in refugial areas and recurrently colonized northern regions during interglacials. Such a history usually results in a loss of genetic diversity. Populations that did not experience glaciations, in contrast, probably maintained most of their ancestral genetic diversity. These characteristics dramatically affected the present-day distribution of genetic diversity and may influence the ability of species to cope with the current global changes. We conducted a range-wide study of mitochondrial genetic diversity in the pine processionary moth (Thaumetopoea pityocampa/T. wilkinsoni complex, Notodontidae, a forest pest occurring around the Mediterranean Basin and in southern Europe. This species is responding to the current climate change by rapid natural range expansion and can also be accidentally transported by humans. Our aim was to assess if Quaternary climatic oscillations had a different effect across the species' range and to determine if genetic footprints of contemporary processes can be identified in areas of recent introduction. Results We identified three main clades that were spatially structured. In most of Europe, the genetic diversity pattern was typical for species that experienced marked glaciation cycles. Except in refugia, European populations were characterized by the occurrence of one main haplotype and by a strong reduction in genetic diversity, which is expected in regions that were rapidly re-colonized when climatic conditions improved. In contrast, all other sub-clades around the Mediterranean Basin occurred in limited parts of the range and were strongly structured in space, as is expected in regions in which the impact of glaciations was limited. In such places, genetic diversity was retained in most populations, and almost all haplotypes were endemic. This

  13. Quaternary climate changes explain diversity among reptiles and amphibians

    DEFF Research Database (Denmark)

    Bastos Araujo, Miguel; Nogués-Bravo, David; Diniz-Filho, Alexandre F.

    2008-01-01

    It is widely believed that contemporary climate determines large-scale patterns of species richness. An alternative view proposes that species richness reflects biotic responses to historic climate changes. These competing "contemporary climate" vs "historic climate" hypotheses have been vigorously...... debated without reaching consensus. Here, we test the proposition that European species richness of reptiles and amphibians is driven by climate changes in the Quaternary. We find that climate stability between the Last Glacial Maximum (LGM) and the present day is a better predictor of species richness...... than contemporary climate; and that the 0°C isotherm of the LGM delimits the distributions of narrow-ranging species, whereas the current 0°C isotherm limits the distributions of wide-ranging species. Our analyses contradict previous studies of large-scale species richness patterns and support the view...

  14. Influence quaternary ammonium salt in the organophilization of an bentonite

    International Nuclear Information System (INIS)

    Oliveira, S.V.; Alves, G.P.; Wanderley, A.S.D.; Araujo, E.M.

    2011-01-01

    Clays are natural materials, earthy, fine-grained particles with diameters generally less than 2μm, and formed by chemically hydrated silicates of aluminum, iron and magnesium. The clays have a range of applications, both in pottery and in other technology areas. This work aimed to study the influence of a quaternary ammonium salt to increase the basal distance of a bentonite clay powder obtained thereby promoting to a new structural profile characteristic with organoclay. The bentonite clay was treated with salt Praepragem WB. The following methods were used: X-ray diffraction (XRD) and X-ray fluorescence (XRF). The results indicated the intercalation of ammonium ions of the salt studied within the layers of silicate and expansion of basal spacing d 001 , ie the clay in the study showed 2θ angle shifts to smaller angles, indicating that the clay was organophilization. (author)

  15. Antibacterial effect of composite resins containing quaternary ammonium polyethyleneimine nanoparticles

    International Nuclear Information System (INIS)

    Yudovin-Farber, Ira; Beyth, Nurit; Weiss, Ervin I.; Domb, Abraham J.

    2010-01-01

    Quaternary ammonium polyethyleneimine (QA-PEI)-based nanoparticles were synthesized by crosslinking with dibromopentane followed by N-alkylation with various alkyl halides and further N-methylation with methyl iodide. Insoluble pyridinium-type particles were prepared by suspension polymerization of 4-vinyl pyridine followed by N-alkylation with alkyl halides. Polyamine-based nanoparticles embedded in restorative composite resin at 1% w/w were tested for antibacterial activity against Streptococcus mutans using direct contact test. Activity analysis revealed that the alkyl chain length of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl-alkylated QA-PEI embedded in restorative composite resin at 1% w/w that totally inhibited S. mutans growth in 3-month-aged samples. This data indicates that restorative composite resin with antibacterial properties can be produced by the incorporation of QA-PEI nanoparticles.

  16. Antibacterial effect of composite resins containing quaternary ammonium polyethyleneimine nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Yudovin-Farber, Ira [Hebrew University of Jerusalem, Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Faculty of Medicine (Israel); Beyth, Nurit; Weiss, Ervin I. [Hebrew University of Jerusalem, Department of Prosthodontics, Faculty of Dentistry (Israel); Domb, Abraham J., E-mail: avid@ekmd.huji.ac.i [Hebrew University of Jerusalem, Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Faculty of Medicine (Israel)

    2010-02-15

    Quaternary ammonium polyethyleneimine (QA-PEI)-based nanoparticles were synthesized by crosslinking with dibromopentane followed by N-alkylation with various alkyl halides and further N-methylation with methyl iodide. Insoluble pyridinium-type particles were prepared by suspension polymerization of 4-vinyl pyridine followed by N-alkylation with alkyl halides. Polyamine-based nanoparticles embedded in restorative composite resin at 1% w/w were tested for antibacterial activity against Streptococcus mutans using direct contact test. Activity analysis revealed that the alkyl chain length of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl-alkylated QA-PEI embedded in restorative composite resin at 1% w/w that totally inhibited S. mutans growth in 3-month-aged samples. This data indicates that restorative composite resin with antibacterial properties can be produced by the incorporation of QA-PEI nanoparticles.

  17. Quaternary geophysical framework of the northeastern North Carolina coastal system

    Science.gov (United States)

    Thieler, E.R.; Foster, D.S.; Mallinson, D.M.; Himmelstoss, E.A.; McNinch, J.E.; List, J.H.; Hammar-Klose, E.S.

    2013-01-01

    The northeastern North Carolina coastal system, from False Cape, Virginia, to Cape Lookout, North Carolina, has been studied by a cooperative research program that mapped the Quaternary geologic framework of the estuaries, barrier islands, and inner continental shelf. This information provides a basis to understand the linkage between geologic framework, physical processes, and coastal evolution at time scales from storm events to millennia. The study area attracts significant tourism to its parks and beaches, contains a number of coastal communities, and supports a local fishing industry, all of which are impacted by coastal change. Knowledge derived from this research program can be used to mitigate hazards and facilitate effective management of this dynamic coastal system.

  18. The geological characteristics during the quaternary period around Japan island

    Energy Technology Data Exchange (ETDEWEB)

    Hagiwara, Shigeru [Chuo Kaihatsu Corp., Enterprises Promotion Bureau, Tokyo (Japan); Sakamoto, Yoshiaki; Ogawa, Hiromichi; Nakayama, Shinichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-11-01

    Radioactive wastes arising from radioisotope facilities and nuclear research facilities should be disposed of in the surface of the earth, the shallow underground, the adequate depth and the deep underground according to radioactivity concentrations, and should be managed during several hundreds years. The earth scientific phenomena observed in Japan island at present occurred continuously from the past, and the same phenomena at the future should occur in the similar factor. Therefore, for the purpose to get the fundamental data for the selection of disposal site, this report reviewed on the genesis and classification of the sediments, earth scientific phenomena observed in Japan island and the feature of each place (10 districts) concerning to the Quaternary period in the newest geological time unit. (author)

  19. Hastings Center

    Science.gov (United States)

    ... Scientists Join Forces Read more HASTINGS CENTER NEWS Artificial intelligence and brain-computer interfaces could revolutionize the treatment ... more HASTINGS CENTER NEWS With the power of artificial intelligence, machines can perform increasingly complex tasks, such as ...

  20. Petrography and petrology of Quaternary volcanic rocks from Ghezel Ghaleh, northwest Qorveh

    OpenAIRE

    Alireza Bajelan; Morteza Sharifi

    2014-01-01

    Introduction In the east and northeast of Sanandaj in the Qorveh-Bijar-Takab axis, there are series of basaltic composition volcanoes with Quaternary age. The study area is part of the Sanandaj-Sirjan zone and is located between 47°52' and 47°57' E longitudes and 35°26 and '35°30' N latitudes. Due to the location of the volcanic cone on Pliocene clastic sediments and Quaternary travertine, the age of these volcanoes is considered to be Quaternary. The cones mostly consist of low scoria, as...

  1. Synthetic Strategies toward Natural Products Containing Contiguous Stereogenic Quaternary Carbon Atoms.

    Science.gov (United States)

    Büschleb, Martin; Dorich, Stéphane; Hanessian, Stephen; Tao, Daniel; Schenthal, Kyle B; Overman, Larry E

    2016-03-18

    Strategies for the total synthesis of complex natural products that contain two or more contiguous stereogenic quaternary carbon atoms in their intricate structures are reviewed with 12 representative examples. Emphasis has been put on methods to create quaternary carbon stereocenters, including syntheses of the same natural product by different groups, thereby showcasing the diversity of thought and individual creativity. A compendium of selected natural products containing two or more contiguous stereogenic quaternary carbon atoms and key reactions in their total or partial syntheses is provided in the Supporting Information. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Timing and sources of neogene and quaternary volcanism in South-Central Guatemala

    Science.gov (United States)

    Reynolds, James H.

    1987-08-01

    Five new and six existing radiometric age dates place constraints on the timing of volcanic episodes in a 1400-km 2 area east of Guatemala City. The source of the voluminous Miocene rhyolitic welded tuffs was the newly discovered Santa Rosa de Lima caldera, in the northern part of the area, not fissure eruptions as was previously believed. Resurgence during the Pliocene included the eruption of more silicic tuffs, followed by post-collapse volcanism around the perimeter. Volcanism in the southern part of the area occurred along the Neogene volcanic front. The sources for these Late Miocene and Pliocene andesitic lavas were not fissure eruptions, as was once believed, but were four large volcanic centers, Cerro Pinula, Ixhuatán, Teanzul, and Cerro La Gabia. The Santa Rosa de Lima caldera structure deflects the Jalpatagua Fault forming tensional fractures along which eruptions in the Quaternary Cuilapa-Barbarena cinder cone field took place. Pleistocene ash flows were erupted from Ixhuatán and Tecuamburro volcanoes in the southern part of the area. Tephras from Ayarza, Amatitlán, and Atitlán blanket the northern and central portions. Present-day activity is restricted to hot springs around the northern and eastern base of Tecuamburro volcano. Based on the work in this area it is proposed that rocks of the Miocene Chalatenango Formation throughout northern Central America were erupted from calderas behind the Neogene volcanic front. Rocks of the Mio-Pliocene Bálsamo Formation in Guatemala and El Salvador were erupted from discrete volcanic centers along the Neogene volcanic front. Pliocene rocks of the Cuscatlán Formation probably represent post-collapse volcanism around earlier caldera structures.

  3. Quaternary epitopes of α345(IV) collagen initiate Alport post-transplant anti-GBM nephritis

    DEFF Research Database (Denmark)

    Olaru, Florina; Luo, Wentian; Wang, Xu-Ping

    2013-01-01

    Alport post-transplant nephritis (APTN) is an aggressive form of anti-glomerular basement membrane disease that targets the allograft in transplanted patients with X-linked Alport syndrome. Alloantibodies develop against the NC1 domain of α5(IV) collagen, which occurs in normal kidneys, including...... of alloantibodies against allogeneic collagen IV. Some alloantibodies targeted alloepitopes within α5NC1 monomers, shared by α345NC1 and α1256NC1 hexamers. Other alloantibodies specifically targeted alloepitopes that depended on the quaternary structure of α345NC1 hexamers. In Col4a5-null mice, immunization...... with native forms of allogeneic collagen IV exclusively elicited antibodies to quaternary α345NC1 alloepitopes, whereas alloimmunogens lacking native quaternary structure elicited antibodies to shared α5NC1 alloepitopes. These results imply that quaternary epitopes within α345NC1 hexamers may initiate...

  4. Late quaternary hillslope evolution recorded in eastern South African colluvial badlands

    CSIR Research Space (South Africa)

    Clarke, ML

    2003-09-01

    Full Text Available matter from buried palaeosols within the colluvial succession shows good agreement between the dating techniques. When compared with palaeo environmental records, the data suggest that the colluvium accumulated during arid stages of the Late Quaternary...

  5. Synthesis of quaternary aryl phosphonium salts: photoredox-mediated phosphine arylation.

    Science.gov (United States)

    Fearnley, A F; An, J; Jackson, M; Lindovska, P; Denton, R M

    2016-04-11

    We report a synthesis method for the construction of quaternary aryl phoshonium salts at ambient temperature. The regiospecific reaction involves the coupling of phosphines with aryl radicals derived from diaryliodonium salts under photoredox conditions.

  6. OMVPE Growth of Quaternary (Al,Ga,In)N for UV Optoelectronics (title change from A)

    Energy Technology Data Exchange (ETDEWEB)

    HAN,JUNG; FIGIEL,JEFFREY J.; PETERSEN,GARY A.; MYERS JR.,SAMUEL M.; CRAWFORD,MARY H.; BANAS,MICHAEL ANTHONY; HEARNE,SEAN JOSEPH

    2000-01-18

    We report the growth and characterization of quaternary AlGaInN. A combination of photoluminescence (PL), high-resolution x-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) characterizations enables us to explore the contours of constant PL peak energy and lattice parameter as functions of the quaternary compositions. The observation of room temperature PL emission at 351nm (with 20% Al and 5% In) renders initial evidence that the quaternary could be used to provide confinement for GaInN (and possibly GaN). AlGaInN/GrdnN MQW heterostructures have been grown; both XRD and PL measurements suggest the possibility of incorporating this quaternary into optoelectronic devices.

  7. Planktonic foraminifera from a quaternary deep sea core from the southern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Rao, P.S.; Pattan, J.N.

    An investigation on planktonic foraminifera and calcium carbonate content of a box core collected at a depth of 2556 m from the southern part of the Arabian sea indicates faunal changes depicting Quaternary climatic fluctuations. Based on the study...

  8. Quaternary Alkylammonium Conjugates of Steroids: Synthesis, Molecular Structure, and Biological Studies

    Directory of Open Access Journals (Sweden)

    Bogumił Brycki

    2015-11-01

    Full Text Available The methods of synthesis as well as physical, spectroscopic (1H-NMR, 13C-NMR, and FT-IR, ESI-MS, and biological properties of quaternary and dimeric quaternary alkylammonium conjugates of steroids are presented. The results were contrasted with theoretical calculations (PM5 methods and potential pharmacological properties (PASS. Alkylammonium sterols exhibit a broad spectrum of antimicrobial activity comparable to squalamine.

  9. NUCLEOPHILIC SUBSTITUTION REACTION OF CYANIDE AND METHOXYDE IONS TO QUATERNARY MANNICH BASE FROM VANILLIN

    OpenAIRE

    Bambang Purwono; Estiana R. P. Daruningsih

    2010-01-01

    The nucleophilic substitution reaction to quaternary Mannich base from vanillin has been investigated. Mannich reaction to vanillin was carried out by refluxing mixture of vanillin, formaldehyde and dimethyl amine. Quaternary ammonium halide salt was obtained from reaction of Mannich vanillin base with methyl iodide in THF solvents and yielded 93.28 %. Nucleophilic substituion to the halide salts with cyanide nucleophile produced 4-hidroxy-3-methoxy-5-(cyano)methylbenzaldehyde in 54.39% yiel...

  10. NUCHLEOPHILIC SUBSTITUTION REACTION OF CYANIDE AND METHOXYDE IONS TO QUATERNARY MANNICH BASE FROM VANILLIN

    OpenAIRE

    Purwono, Bambang; Daruningsih, Estiana E.P

    2010-01-01

    The nucleophilic substitution reaction to quaternary Mannich base from vanillin has been investigated. Mannich reaction to vanillin was carried out by refluxing mixture of vanillin, formaldehyde and dimethyl amine. Quaternary ammonium halide salt was obtained from reaction of Mannich vanillin base with methyl iodide in THF solvents and yielded  93.28%. Nucleophilic substituion to the halide salts with cyanide nucleophile produced 4-hidroxy-3-methoxy-5-(cyano)methylbenzaldehyde in 54.39% yield...

  11. The pragmatic roots of American Quaternary geology and geomorphology

    Science.gov (United States)

    Baker, Victor R.

    1996-07-01

    H.L. Fairchild's words from the 1904 Geological Society of America Bulletin remain appropriate today: "Geologists have been too generous in allowing other people to make their philosophy for them". Geologists have quietly followed a methodological trinity involving (1) inspiration by analogy, (2) impartial and critical assessment of hypotheses, and (3) skepticism of authority (prevailing theoretical constraints or paradigms). These methods are described in classical papers by Quaternary geologists and geomorphologists, mostly written a century ago. In recent years these papers have all been criticized in modern philosophical terms with little appreciation for the late 19th century American philosophical tradition from which they arose. Recent scholarly research, however, has revealed some important aspects of that tradition, giving it a coherence that has largely been underappreciated as 20th century philosophy of science pursued its successive fads of logical positivism, critical rationalism, relativism, and deconstructivism — for all of which "science" is synonymous with "physics". Nearly all this ideology is geologically irrelevant. As philosophy of science in the late 20th century has come to be identical with philosophy of analytical physics, focused on explanations via ideal truths, much of geology has remained true to its classical doctrines of commonsensism, fallibilism, and realism. In contrast to the conceptualism and the reductionism of the analytical sciences, geology has emphasized synthetic thinking: the continuous activity of comparing, connecting, and putting together thoughts and perceptions. The classical methodological studies of geological reasoning all concern the formulation and testing of hypotheses. Analysis does not serve to provide the ultimate answers for intellectual puzzles predefined by limiting assumptions imposed on the real world. Rather, analysis in geology allows the investigator to consider the consequential effects of

  12. Sequential character of low-energy ternary and quaternary nuclear fission

    Science.gov (United States)

    Kadmensky, S. G.; Bulychev, A. O.

    2016-09-01

    An analysis of low-energy true ternary (quaternary) nuclear fission leads to the conclusion that these fission modes have a sequential two-step (three-step) character such that the emission of a third particle (third and fourth particles) and the separation of fission fragments occur at distinctly different instants, in contrast to the simultaneous emergence of all fission products in the case of onestep ternary (quaternary) fission. This conclusion relies on the following arguments. First, the emission of a third particle (third and fourth particles) from a fissile nucleus is due to a nonevaporative mechanism associated with a nonadiabatic character of the collective deformation motion of this nucleus at the stages preceding its scission. Second, the axial symmetry of the deformed fissile compound nucleus and the direction of its symmetry axis both remain unchanged at all stages of ternary (quaternary) fission. This circumstancemakes it possible to explain themechanism of the appearance of observed anisotropies and T — odd asymmeries in the angular distributions of products of ternary (quaternary) nuclear fission. Third, the T —odd asymmetry discovered experimentally in ternary nuclear fission induced by cold polarized neutrons obeys the T —invariance condition only in the case of a sequential two-step (three-step) character of true ternary (quaternary) nuclear fission. At the same time, this asymmetry is not a T —invariant quantity in the case of the simultaneous emission of products of true ternary (quaternary) nuclear fission from the fissile compound nucleus.

  13. A comparative study of ICH validated novel spectrophotometric techniques for resolving completely overlapping spectra of quaternary mixtures

    Science.gov (United States)

    Ali, Nouruddin W.; Abdelwahab, Nada S.; Abdelkawy, M.; Emam, Aml A.

    2016-02-01

    A pharmaceutically marketed mixture of Yohimbine, Alpha-tocopheryl acetate, Niacin, and Caffeine co-formulated as a promising therapy for erectile dysfunction. Simultaneous determination of the aforementioned pharmaceutical formulation without prior separation steps was applied using mean centering of ratio spectra and triple divisor spectrophotometric methods. Mean centering of ratio spectra method depended on using the mean centered ratio spectra in three successive steps which eliminated the derivative steps and so the signal to noise ratio was improved. The absorption spectra of the prepared solutions were measured in the wavelength range of 215-300 nm in the concentration ranges of 1-15, 3-15, 1-20, and 3-15 μg mL- 1 for Yohimbine, Alpha-tocopheryl acetate, Niacin, and Caffeine, respectively. The amplitudes of the mean centered third ratio spectra were measured at 250 nm and 268 nm for Yohimbine and Alpha-tocopheryl acetate, respectively and at peak to peak 272-273 and 262-263 nm for Niacin and Caffeine, respectively. In triple divisor method each drug in the quaternary mixture was determined by dividing the spectrum of the quaternary mixture by a standard spectrum of a mixture containing equal concentrations of the other three drugs. First derivative of these ratio spectra was obtained where determination could be achieved without any interference from the other three drugs. Amplitudes of 1-15, 3-15, 1-15, and 3-15 μg mL- 1 were used for selective determination of Yohimbine, Alpha-tocopheryl acetate, Niacin, and Caffeine, respectively. Laboratory prepared mixtures were analyzed by the developed novel methods to investigate their selectivity also, Super Act® capsules were successfully analyzed to ensure absence of interference from additives. The developed methods were validated according to the ICH guidelines. The proposed methods were statistically compared with each other and with the reported methods; using student t-test, F-test, and one way ANOVA

  14. The Quaternary fossil avifauna of Southland, South Island, New Zealand

    International Nuclear Information System (INIS)

    Worthy, T.H.

    1998-01-01

    All known Late Quaternary fossil avifauna derived, at various times during the last century, from cave, swamp and dune deposits in Southland, South Island, New Zealand, are described. Fifty eight native bird species are recorded from the deposits, notably including the fourth recort of ''Dendroscansor decurvirostris''. The few leiopelmatid and spenodontid bones are also listed. Taphonomic biases limit comparison of faunal compositions across site-types to moas. However, the moa faunas reveal that quite different avifauna lived in each of the dunes, alluvial swamplands and the well-drained low hills, which probably reflects different vegetation communities in each. Southland supported a mosaic of grassland, shrubland and tall, closed-canopy podocarp forest during the Holocene. Radiocarbon dates on bone gelatin are presented that indicate the fauna of Castle Rocks is of Late-Holocene age, the fauna from Hamiltons Swamp at Winton is of mid-Holocene age, and that from Kauana is >37 080 years old. Is is the oldest swamp fauna so far identified in New Zealand. (author). 61 refs., 6 figs., 5 tabs., 2 appendices

  15. Quaternary history of the Kiseiba Oasis region, southern Egypt

    Science.gov (United States)

    Maxwell, Ted A.; Haynes, C. Vance; Nicoll, Kathleen; Johnston, Andrew K.; Grant, John A.; Kilani, Ali

    2017-12-01

    Kiseiba Oasis and depression are located in southern Egypt between the Selima Sand Sheet to the west and the Nile to the east, an important area that hosted Late Cenozoic drainage, Middle Pleistocene lakes, and numerous Paleolithic and Neolithic cultural sites. A synthesis of orbital data, field surveying and near-surface stratigraphy provides new insights into the Quaternary history of this region. Shuttle Imaging Radar data show a complex of fluvial channels that are due to stringers of surficial fluvial lag, subsurface fluvial deposits, and areas of deep alluvium. Three topographic surfaces are described: 1) the Atmur El-Kibeish, above 230 m elevation, which displays a linear pattern of light radar returns, possibly formed from northeast drainage; 2) the Acheulean Surface, at 200 m elevation, that has dark radar patterns resulting from thick alluvium bounded by pebble sand and calcrete strata, and 3) the Kiseiba Surface, below 190 m, that has a complex series of surface and subsurface fluvial and aeolian sediments. Initial drainage from the Early through Middle Pleistocene was to the northeast, which may have lasted through the Last Interglacial. Later reworking of sediments during the Last Glacial Maximum and the Holocene resulted in topographic inversion, with any subsequent local drainage on the Kiseiba Surface to the southwest, towards the Kiseiba Scarp.

  16. Quaternary glaciation of the Tashkurgan Valley, Southeast Pamir

    Science.gov (United States)

    Owen, Lewis A.; Chen, Jie; Hedrick, Kathyrn A.; Caffee, Marc W.; Robinson, Alexander C.; Schoenbohm, Lindsay M.; Yuan, Zhaode; Li, Wenqiao; Imrecke, Daniel B.; Liu, Jinfeng

    2012-07-01

    The Quaternary glacial history of Tashkurgan valley, in the transition between the Pamir and Karakoram, in Xinjiang Province, China was examined using remote sensing, field mapping, geomorphic analysis of landforms and sediments, and 10Be terrestrial cosmogenic nuclide dating. Moraines were assigned to four glacial stages: 1) the Dabudaer glacial stage that dates to the penultimate glacial cycle and/or earlier, and may represent one or more glaciations; 2) the Tashkurgan glacial stage that dates to early last glacial, most likely Marine Oxygen Isotope Stage (MIS) 4; 3) the Hangdi glacial stage that dates to MIS 2, possibly early MIS 2; and 4) the Kuzigun glacial stage that dates to the MIS 2, possibly the global Last Glacial Maximum, and is younger than the Hangdi glacial stage. Younger moraines and rock glaciers are present at the heads of tributary valleys; but these were inaccessible because they are located close to politically sensitive borders with Pakistan, Afghanistan and Tajikistan. Glaciers during the Dabudaer glacial stage advanced into the central part of the Tashkurgan valley. During the Tashkurgan glacial stages, glaciers advanced several kilometers beyond the mouths of the tributary valleys into the Tashkurgan valley. Glaciers during the Hangdi and Kuzigun glacial stages advanced just beyond the mouths of the tributary valleys. Glaciation in this part of the Himalayan-Tibetan orogen is likely strongly controlled by northern hemisphere climate oscillations, although a monsoonal influence on glaciation cannot be ruled out entirely.

  17. Effects of late quaternary climate change on Palearctic shrews.

    Science.gov (United States)

    Prost, Stefan; Klietmann, Johannes; van Kolfschoten, Thijs; Guralnick, Robert P; Waltari, Eric; Vrieling, Klaas; Stiller, Mathias; Nagel, Doris; Rabeder, Gernot; Hofreiter, Michael; Sommer, Robert S

    2013-06-01

    The Late Quaternary was a time of rapid climatic oscillations and drastic environmental changes. In general, species can respond to such changes by behavioral accommodation, distributional shifts, ecophenotypic modifications (nongenetic), evolution (genetic) or ultimately face local extinction. How those responses manifested in the past is essential for properly predicting future ones especially as the current warm phase is further intensified by rising levels of atmospheric carbon dioxide. Here, we use ancient DNA (aDNA) and morphological features in combination with ecological niche modeling (ENM) to investigate genetic and nongenetic responses of Central European Palearctic shrews to past climatic change. We show that a giant form of shrew, previously described as an extinct Pleistocene Sorex species, represents a large ecomorph of the common shrew (Sorex araneus), which was replaced by populations from a different gene-pool and with different morphology after the Pleistocene Holocene transition. We also report the presence of the cold-adapted tundra shrew (S. tundrensis) in Central Europe. This species is currently restricted to Siberia and was hitherto unknown as an element of the Pleistocene fauna of Europe. Finally, we show that there is no clear correlation between climatic oscillations within the last 50 000 years and body size in shrews and conclude that a special nonanalogous situation with regard to biodiversity and food supply in the Late Glacial may have caused the observed large body size. © 2013 Blackwell Publishing Ltd.

  18. Quaternary climate change and the geographic ranges of mammals.

    Science.gov (United States)

    Davies, T Jonathan; Purvis, Andy; Gittleman, John L

    2009-09-01

    A species' range can be a proxy for its ecological well-being. Species with small and shrinking range distributions are particularly vulnerable to extinction. Future climate change scenarios are predicted to affect species' geographical extents, but data on how species' distributions respond to changing climate are largely anecdotal, and our understanding of the determinants and limits to species geographic ranges is surprisingly poor. Here we show that mammal species in more historically variable environments have larger geographical ranges. However, the relationship between range size and long-term climate trends cannot be explained by variation in our estimates of habitat specificity. We suggest that large oscillations in Quaternary temperatures may have shaped the contemporary distribution of range sizes via the selective extirpation of small-ranged species during glacial expansion and/or recolonization by good dispersers after glacial retreats. The effect of current climate change on species' distributions and extinctions may therefore be determined by the geographical coincidence between historical and future climate scenarios, the "mesh size" of the extinction/dispersal filter imposed by past climate change, and whether similar ecological and evolutionary responses to historical climatic change are appropriate in an increasingly transformed and fragmented landscape.

  19. Late Quaternary environments, vegetation and agriculture in northern New Zealand

    Science.gov (United States)

    Horrocks, M.; Nichol, S. L.; Augustinus, P. C.; Barber, I. G.

    2007-03-01

    A sedimentological and plant microfossil history of the Late Quaternary is preserved in two sediment cores from early Polynesian ditch systems on southern Aupouri Peninsula. The study places human activities into a geomorphological and ecological context and allows comparison of natural and anthropogenic effects on two different geological settings: a floodplain and a relatively closed peat swamp. The data fill part of the current gap in the environmental record from northern New Zealand, namely MIS 3 (57k-26k yr BP). There is evidence for an increase in fire frequency in the region after 40k 14C yr BP, suggesting a shift to drier (and cooler) conditions. Pollen records show that conifer-hardwood forest dominated by podocarps (especially Dacrydium) prevailed prior to Polynesian arrival and deforestation within the last millennium, with Fuscopsora insignificant throughout. Both cores show sections with gaps in deposition or preservation, possible flood-stripping of peat during the pre-Holocene and mechanical disturbance by early Polynesians. The identification of prehistoric starch grains and other microremains of introduced Colocasia esculenta (taro) in both cores supports indirect evidence that the ditch systems of far northern New Zealand were used for the extensive cultivation of this crop. Copyright

  20. Antibacterial Activity of Dental Cements Containing Quaternary Ammonium Polyethylenimine Nanoparticles

    International Nuclear Information System (INIS)

    Beyth, N.; Weiss, E.I.; Pilo, R.

    2012-01-01

    Glass ionomer cements (GICs) are commonly used for cementing full cast crown restorations. Regrettably, although the dental cements fill the gap between the tooth and the crown, bacterial micro leakage may occur, resulting in secondary caries. As micro leakage cannot be completely prevented, GCS possessing antibacterial properties are in demand. In the present study the antibacterial activity of insoluble, cross-linked quaternary ammonium polyethylenimine (Qp) nanoparticles incorporated at 1% w/w in two clinically available GCS were studied. The antibacterial activity was tested against Streptococcus mutans and Lactobacillus casei using the direct contact test (Dct) and the agar diffusion test (Ad). Using the direct contact test, antibacterial activity (P<0.05) was found in both tested GICs with incorporated QPEI nanoparticles, the effect lasting for at least one month. However, the ADT showed no inhibition halo in the test bacteria, indicating that the antimicrobial nanoparticles do not diffuse into the agar. The results show that the incorporation of QPEI nanoparticles in glass ionomer cements has a long-lasting antibacterial effect against Streptococcus mutans and Lactobacillus casei. Changing the antibacterial properties of glass ionomer cements by incorporating QPEI antibacterial nanoparticles may prolong the clinical performance of dental crowns.

  1. Preliminary Groundwater Assessment using Electrical Method at Quaternary Deposits Area

    Science.gov (United States)

    Hazreek, Z. A. M.; Raqib, A. G. A.; Aziman, M.; Azhar, A. T. S.; Khaidir, A. T. M.; Fairus, Y. M.; Rosli, S.; Fakhrurrazi, I. M.; Izzaty, R. A.

    2017-08-01

    Alternative water sources using groundwater has increasingly demand in recent years. In the past, proper and systematic study of groundwater potential was varies due to several constraints. Conventionally, tube well point was drilled based on subjective judgment of several parties which may lead to the uncertainties of the project success. Hence, this study performed an electrical method to investigate the groundwater potential at quaternary deposits area particularly using resistivity and induced polarization technique. Electrical method was performed using ABEM SAS4000 equipment based on pole dipole array and 2.5 m electrode spacing. Resistivity raw data was analyzed using RES2DINV software. It was found that groundwater was able to be detected based on resistivity and chargeability values which varied at 10 - 100 Ωm and 0 - 1 ms respectively. Moreover, suitable location of tube well was able to be proposed which located at 80 m from the first survey electrode in west direction. Verification of both electrical results with established references has shown some good agreement thus able to convince the result reliability. Hence, the establishment of electrical method in preliminary groundwater assessment was able to assist several parties in term groundwater prospective at study area which efficient in term of cost, time, data coverage and sustainability.

  2. Ordering tendencies and electronic properties in quaternary Heusler derivatives

    Science.gov (United States)

    Neibecker, Pascal; Gruner, Markus E.; Xu, Xiao; Kainuma, Ryosuke; Petry, Winfried; Pentcheva, Rossitza; Leitner, Michael

    2017-10-01

    The phase stabilities and ordering tendencies in the quaternary full-Heusler alloys NiCoMnAl and NiCoMnGa have been investigated by in situ neutron diffraction, calorimetry, and magnetization measurements. NiCoMnGa was found to adopt the L 21 structure, with distinct Mn and Ga sublattices but a common Ni-Co sublattice. A second-order phase transition to the B 2 phase with disorder also between Mn and Ga was observed at 1160 K . In contrast, in NiCoMnAl slow cooling or low-temperature annealing treatments are required to induce incipient L 21 ordering, otherwise the system displays only B 2 order. Linked to L 21 ordering, a drastic increase in the magnetic transition temperature was observed in NiCoMnAl, while annealing affected the magnetic behavior of NiCoMnGa only weakly due to the low degree of quenched-in disorder. First principles calculations were employed to study the thermodynamics as well as order-dependent electronic properties of both compounds. It was found that a near half-metallic pseudogap emerges in the minority spin channel only for the completely ordered Y structure. However, this structure is energetically unstable compared to a tetragonal structure with alternating layers of Ni and Co, which is predicted to be the low-temperature ground state. The experimental inaccessibility of the totally ordered structures is explained by kinetic limitations due to the low ordering energies.

  3. Electrochemical properties of quaternary ammonium salts for electrochemical capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Ue, Makoto; Takeda, Masayuki; Takehara, Masahiro; Mori, Shoichiro [Mitsubishi Chemical Corp., Inashiki, Ibaraki (Japan). Tsukuba Research Center

    1997-08-01

    The limiting reduction and oxidation potentials and electrolytic conductivities of new quaternary ammonium salts were examined for electrochemical capacitor applications, whose anions have already been tested as lithium salts for lithium battery applications. The anodic stability was in the following order BR{sub 4}{sup {minus}} < ClO{sub 4}{sup {minus}} {le} CF{sub 3}SO{sub 3}{sup {minus}} < (CF{sub 3}SO{sub 2}){sub 2}N{sup {minus}} {le} C{sub 4}F{sub 9}SO{sub 3}{sup {minus}} < BF{sub 4}{sup {minus}} < PF{sub 6}{sup {minus}} {le} AsF{sub 6}{sup {minus}} < SbF{sub 6}{sup {minus}}. The electrolytic conductivities of Me{sub 4{minus}n}Et{sub n}N(CF{sub 3}SO{sub 2}){sub 2}N (n = 0--4) were examined in comparison with Me{sub 4{minus}n}Et{sub n}NBF{sub 4} counterparts. These imide salts showed good solubility, relatively high conductivity, and anodic stability in propylene carbonate. Et{sub 4}N(CF{sub 3}SO{sub 2}){sub 2}N was found to be a good supporting salt for low permittivity organic solvents, and it afforded a highly conductive electrolyte system based on the ethylene carbonate-dimethyl carbonate mixed solvent, which is useful for electrochemical capacitor applications.

  4. Ligand exchange in quaternary alloyed nanocrystals--a spectroscopic study.

    Science.gov (United States)

    Gabka, Grzegorz; Bujak, Piotr; Giedyk, Kamila; Kotwica, Kamil; Ostrowski, Andrzej; Malinowska, Karolina; Lisowski, Wojciech; Sobczak, Janusz W; Pron, Adam

    2014-11-14

    Exchange of initial, predominantly stearate ligands for pyridine in the first step and butylamine (BA) or 11-mercaptoundecanoic acid (MUA) in the second one was studied for alloyed quaternary Cu-In-Zn-S nanocrystals. The NMR results enabled us to demonstrate, for the first time, direct binding of the pyridine labile ligand to the nanocrystal surface as evidenced by paramagnetic shifts of the three signals attributed to its protons to 7.58, 7.95 and 8.75 ppm. XPS investigations indicated, in turn, a significant change in the composition of the nanocrystal surface upon the exchange of initial ligands for pyridine, which being enriched in indium in the 'as prepared' form became enriched in zinc after pyridine binding. This finding indicated that the first step of ligand exchange had to involve the removal of the surface layer enriched in indium with simultaneous exposure of a new, zinc-enriched layer. In the second ligand exchange step (replacement of pyridine with BA or MUA) the changes in the nanocrystal surface compositions were much less significant. The presence of zinc in the nanocrystal surface layer turned out necessary for effective binding of pyridine as shown by a comparative study of ligand exchange in Cu-In-Zn-S, Ag-In-Zn-S and CuInS2, carried out by complementary XPS and NMR investigations.

  5. Quaternary climatic variability in the Tarat aquifer (Arlit, Niger)

    International Nuclear Information System (INIS)

    Dodo, A.; Zuppi, G.M.

    1999-01-01

    The concentration of major elements and environmental isotopes in the Carboniferous (Guezouman and Tarat), Triassic (Teloua) and Quaternary aquifers allows to describe the ground-water flow and to define the upward leakage. 18 O and 2 H in water samples from Guezouman and some Tarat aquifers fall on a regressive line with the equation, δ 2 H (8.01±0.50) δ 18 O + (3.85±3.56), similar to that found for old groundwater in the northern and southern Sahara. The isotopic difference between the Arlit area and the easterly Djado basin groundwater results from the combined effects of continentality and altitude on meteoric waters. The carbon 14 ages, the palaeo-temperatures evaluated from oxygen 18 and nitrate contents in the Tarat aquifer show climatic variations consisting of two humid periods at 10 000 and 30 000 years separated by a warmer period at 25 000. The mean temperatures of the palaeo-recharge, estimated using oxygen 18 data, are 18 deg C during the Holocene, 20 deg C at 25 000 years and 16 deg C at 30 000 years. Water infiltrating during the warming period shows 79 mg L -1 nitrates. High nitrates could be due to an important meteorological event which entrained and stored organic matter from the surface vegetation and soil by infiltration. (authors)

  6. Antibacterial Activity of Dental Cements Containing Quaternary Ammonium Polyethylenimine Nanoparticles

    Directory of Open Access Journals (Sweden)

    Nurit Beyth

    2012-01-01

    Full Text Available Glass ionomer cements (GICs are commonly used for cementing full cast crown restorations. Regrettably, although the dental cements fill the gap between the tooth and the crown, bacterial microleakage may occur, resulting in secondary caries. As microleakage cannot be completely prevented, GICs possessing antibacterial properties are in demand. In the present study the antibacterial activity of insoluble, cross-linked quaternary ammonium polyethylenimine (QPEI nanoparticles incorporated at 1% w/w in two clinically available GICs were studied. The antibacterial activity was tested against Streptococcus mutans and Lactobacillus casei using the direct contact test (DCT and the agar diffusion test (ADT. Using the direct contact test, antibacterial activity (<0.05 was found in both tested GICs with incorporated QPEI nanoparticles, the effect lasting for at least one month. However, the ADT showed no inhibition halo in the test bacteria, indicating that the antimicrobial nanoparticles do not diffuse into the agar. The results show that the incorporation of QPEI nanoparticles in glass ionomer cements has a long-lasting antibacterial effect against Streptococcus mutans and Lactobacillus casei. Changing the antibacterial properties of glass ionomer cements by incorporating QPEI antibacterial nanoparticles may prolong the clinical performance of dental crowns.

  7. Large-scale and patternable graphene: direct transformation of amorphous carbon film into graphene/graphite on insulators via Cu mediation engineering and its application to all-carbon based devices.

    Science.gov (United States)

    Chen, Yu-Ze; Medina, Henry; Lin, Hung-Chiao; Tsai, Hung-Wei; Su, Teng-Yu; Chueh, Yu-Lun

    2015-02-07

    Chemical vapour deposition of graphene was the preferred way to synthesize graphene for multiple applications. However, several problems related to transfer processes, such as wrinkles, cleanness and scratches, have limited its application at the industrial scale. Intense research was triggered into developing alternative synthesis methods to directly deposit graphene on insulators at low cost with high uniformity and large area. In this work, we demonstrate a new concept to directly achieve growth of graphene on non-metal substrates. By exposing an amorphous carbon (a-C) film in Cu gaseous molecules after annealing at 850 °C, the carbon (a-C) film surprisingly undergoes a noticeable transformation to crystalline graphene. Furthermore, the thickness of graphene could be controlled, depending on the thickness of the pre-deposited a-C film. The transformation mechanism was investigated and explained in detail. This approach enables development of a one-step process to fabricate electrical devices made of all carbon material, highlighting the uniqueness of the novel approach for developing graphene electronic devices. Interestingly, the carbon electrodes made directly on the graphene layer by our approach offer a good ohmic contact compared with the Schottky barriers usually observed on graphene devices using metals as electrodes.

  8. Setting the Time Frame - Investigating Culture-Environment Interactions in the Late Quaternary

    Science.gov (United States)

    Klasen, N.; Just, J.; Rethemeyer, J.

    2015-12-01

    We present a status update of luminescence age estimates of sediments from Ethiopia and the Iberian Peninsula that are related to human occupation and are currently being investigated in the interdisciplinary Collaborative Research Center "Our way to Europe - Culture-Environment Interaction and Human Mobility in the Late Quaternary" (CRC806). The aim of the project is to investigate the dispersal of anatomically modern humans from Africa to Europe, and a robust chronology is essential. In the CRC806, dating is provided by luminescence, palaeomagnetic and radiocarbon techniques. A key site of the CRC806 is Chew Bahir in Ethiopia. This lake basin is located in the source area of the emergence of anatomically modern humans. Radiocarbon, luminescence and palaeomagnetic dating have been used to develop an age-depth model for drill core sediments that date back to 115 ka over 42 m depth. The model is independent of palaeoclimatic proxy interpretation. On the Iberian Peninsula cave deposits have been dated with luminescence techniques and compared to radiocarbon ages wherever applicable. Recently, existing radiocarbon chronologies on the Iberian Peninsula have been revised in light of methodological developments. Robust luminescence dating is therefore especially important in this region, where the stratigraphy is difficult to constrain. We aim to improve the precision of luminescence age estimates by comparing different measurement techniques for equivalent dose and dose-rate determinations, and by using Bayesian statistics to develop age-depth models. Combining different chronological techniques has enabled the development of accurate and precise chronologies, which will allow a better understanding of the emergence of modern humans.

  9. Usage Center

    DEFF Research Database (Denmark)

    Kleinaltenkamp, Michael; Plewa, Carolin; Gudergan, Siegfried

    2017-01-01

    Purpose: The purpose of this paper is to advance extant theorizing around resourceintegration by conceptualizing and delineating the notion of a usage center. Ausage center consists of a combination of interdependent actors that draw onresources across their individual usage processes to create...... value.Design/methodology/approach:This paper provides a conceptual inquiry into the usage center. Findings: This paper delineates the notion of a usage center by way of focal andperipheral resource integrators, as well as focal and peripheral resources thatform part of interdependent resource usage...... processes. The conceptual analysisreveals the need for resources to be accessible and shareable to focal andperipheral actors, with rivalry and emergence central factors influencing theactor’s usage processes.Originality/value: Responding to recent calls for research developing insights intomulti...

  10. Equiatomic quaternary Heusler alloys: A material perspective for spintronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Bainsla, Lakhan, E-mail: lakhanbainsla@gmail.com, E-mail: suresh@phy.iitb.ac.in; Suresh, K. G., E-mail: lakhanbainsla@gmail.com, E-mail: suresh@phy.iitb.ac.in [Magnetic Materials Lab, Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India)

    2016-09-15

    Half-metallic ferromagnetic (HMF) materials show high spin polarization and are therefore interesting to researchers due to their possible applications in spintronic devices. In these materials, while one spin sub band has a finite density of states at the Fermi level, the other sub band has a gap. Because of their high Curie temperature (T{sub C}) and tunable electronic structure, HMF Heusler alloys have a special importance among the HMF materials. Full Heusler alloys with the stoichiometric composition X{sub 2}YZ (where X and Y are the transition metals and Z is a sp element) have the cubic L2{sub 1} structure with four interpenetrating fcc sublattices. When each of these four fcc sublattices is occupied by different atoms (XX′YZ), a quaternary Heusler structure with different structural symmetries (space group F-43m, #216) is obtained. Recently, these equiatomic quaternary Heusler alloys (EQHAs) with 1:1:1:1 stoichiometry have attracted a lot of attention due to their superior magnetic and transport properties. A special class of HMF materials identified recently is known as spin gapless semiconductors (SGS). The difference in this case, compared with HMFs, is that the density of states for one spin band is just zero at the Fermi level, while the other has a gap as in the case of HMFs. Some of the reported SGS materials belong to EQHAs family. This review is dedicated to almost all reported materials belonging to EQHAs family. The electronic structure and hence the physical properties of Heusler alloys strongly depend on the degree of structural order and distribution of the atoms in the crystal lattice. A variety of experimental techniques has been used to probe the structural parameters and degree of order in these alloys. Their magnetic properties have been investigated using the conventional methods, while the spin polarization has been probed by point contact Andreev reflection technique. The experimentally obtained values of saturation magnetization are

  11. The role of Thaumarchaeota in the Quaternary nitrogen cycle

    Science.gov (United States)

    Dong, L.; Jia, G.; Zhiyang, L.; Wu, Z.

    2016-12-01

    Paired downcore profiles of sedimentary organic δ15N, and crenarchaeol, a specific biomarker of Thaumarchaeota, the ammonia oxidation archaea, were reported from marine isotope stage (MIS) 6 to MIS2 in core MD05-2897 and from MIS2 to MIS1 in core MD01-2392 to explore the role of Thaumarchaeota in the Quaternary nitrogen biogeochemical cycles. Both cores were retrieved from the southern South China Sea (SCS). The δ15N glacial-interglacial patterns of the two cores were opposite to the existing tropical eastern Pacific records, with decreasing trend during deglacial periods and high values in the glacial times and low values in the interglacial intervals (from 5 to 3.5‰), but were consistent with the foraminiferal bound δ15N record in the northern SCS. Basically, the crenarchaeol abundance paralleled the curve of δ15N record during glacial-interglacial timescale, indicating enhanced archaeal ammonia oxidation occurred during both deglacial and interglacial intervals, which could lower the δ15N value of the remaining NO3- via the release of 15N-enriched N2O. The proposed stronger archaeal ammonia oxidization in the interglacial SCS could reasonably account for the opposite trend of the δ15N record in the denitrification zone of the eastern Pacific. In addition, the paired records of GDGT [2]/[3] ratio, a proxy for evaluating the relative ratio of shallow and deep AOA, was found also coupled with the δ15N record, indicating the increase contribution of nitrification from the shallow AOA in the interglacial periods. Although our findings here are not in conflict with the hypothesis that the nitrogen fixation enhanced during interglacial periods, they can further suggest that organic matter mineralization in the euphotic zone, which could provide ammonia for AOA, likely enhanced more during the interglacials and then ultimately reduced the biological pump efficiency.

  12. Antimicrobial Nanocomposites Prepared from Montmorillonite/Ag+/Quaternary Ammonium Nitrate

    Directory of Open Access Journals (Sweden)

    Lin Zhang

    2018-01-01

    Full Text Available Nanocomposites of Ag with organic montmorillonite (Ag-OMMT, Ag with montmorillonite (Ag-MMT, and organic montmorillonite (OMMT were successfully prepared via a one-step solution-intercalated method. Sodium MMT, silver nitrate, and dimethyl octadecyl hydroxy ethyl ammonium nitrate were used as precursors. X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and energy dispersive spectroscopy analyses confirmed that the MMT layers were intercalated, and Ag+ was partly reduced to silver nanoparticles with diameters within 10–20 nm in Ag-OMMT. The decomposition temperature of the organic cations in OMMT and Ag-OMMT increased to 220°C, as revealed by differential scanning calorimetry-thermogravimetric analysis. The antimicrobial activity of the nanocomposites was tested by measuring the minimum inhibitory concentration (MIC and killing rate. The MICs of Ag-OMMT against Staphylococcus aureus, Escherichia coli, and Candida albicans were 0.313, 2.5, and 0.625 mg/mL, respectively. Because of the presence of quaternary ammonium nitrate, Ag-OMMT has a better MIC against Gram-positive bacteria compared to Gram-negative bacteria and fungi. OMMT did not show antimicrobial activity against Escherichia coli and Candida albicans. In 2 h, 0.0125 mg/mL Ag-OMMT could kill 100% of S. aureus, E. coli, and C. albicans in solution, and Ag-MMT could kill 99.995% of S. aureus, 90.15% of E. coli, and 93.68% of C. albicans. These antimicrobial functional nanocomposites have the potential for application in the area of surface decoration films.

  13. Quaternary extensional growth folding beneath Reno, Nevada, imaged by urban seismic profiling

    Science.gov (United States)

    Stephenson, William J.; Frary, Roxy N.; Louie, John; Odum, Jackson K.

    2013-01-01

    We characterize shallow subsurface faulting and basin structure along a transect through heavily urbanized Reno, Nevada, with high‐resolution seismic reflection imaging. The 6.8 km of P‐wave data image the subsurface to approximately 800 m depth and delineate two subbasins and basin uplift that are consistent with structure previously inferred from gravity modeling in this region of the northern Walker Lane. We interpret two primary faults that bound the uplift and deform Quaternary deposits. The dip of Quaternary and Tertiary strata in the western subbasin increases with greater depth to the east, suggesting recurrent fault motion across the westernmost of these faults. Deformation in the Quaternary section of the western subbasin is likely evidence of extensional growth folding at the edge of the Truckee River through Reno. This deformation is north of, and on trend with, previously mapped Quaternary fault strands of the Mt. Rose fault zone. In addition to corroborating the existence of previously inferred intrabasin structure, these data provide evidence for an active extensional Quaternary fault at a previously unknown location within the Truckee Meadows basin that furthers our understanding of both the seismotectonic framework and earthquake hazards in this urbanized region.

  14. The ichthyofauna of limnic systems in Quaternary deposits of extreme southern Brazil

    Directory of Open Access Journals (Sweden)

    Cindy Marques

    2016-12-01

    Full Text Available The Quaternary in the state of Rio Grande do Sul (RS, southern Brazil, is geologically represented by the coastal plain and was originated by successive events of Pleistocene-Holocene marine transgressions and the occurrence of alluvial deposits. This paper aimed to characterize the fish assemblage occurring in a swampy Quaternary area adjacent to Lagoa Pequena, a lacustrine system connected to the west margin of the Laguna dos Patos estuary. A checklist is also provided of the ichthyofauna so far recorded in limnic systems of Quaternary deposits in the state of Rio Grande do Sul. A total of 42 species was recorded, distributed in nine orders, 18 families and 31 genera. Characidae and Cichlidae were the most representative families, comprising 15 and 4 species respectively. A bibliographic revision associated to our sample data revealed the occurrence of 156 species in limnic systems inserted in RS Quaternary deposits (114 limnic, 15 marine/estuarine/limnic, ten marine/estuarine, nine estuarine/limnic and eight marine. Characiformes and Siluriformes are the most diverse orders, corroborating the Neotropical pattern. Seven species can be considered endemic to RS Quaternary deposits.

  15. Atomic-scale properties of Ni-based FCC ternary, and quaternary alloys

    International Nuclear Information System (INIS)

    Tamm, Artur; Aabloo, Alvo; Klintenberg, Mattias; Stocks, Malcolm; Caro, Alfredo

    2015-01-01

    The aim of this study is to characterize some atomic-scale properties of Ni-based FCC multicomponent alloys. For this purpose, we use Monte Carlo method combined with density functional theory calculations to study short-range order (SRO), atomic displacements, electronic density of states, and magnetic moments in equimolar ternary NiCrCo, and quaternary NiCrCoFe alloys. According to our study, the salient features for the ternary alloy are a negative SRO parameter between Ni–Cr and a positive between Cr–Cr pairs as well as a weakly magnetic state. For the quaternary alloy we predict negative SRO parameter for Ni–Cr and Ni–Fe pairs and positive for Cr–Cr and Fe–Fe pairs. Atomic displacements for both ternary and quaternary alloys are negligible. In contrast to the ternary, the quaternary alloy shows a complex magnetic structure. The electronic structure of the ternary and quaternary alloys shows differences near the Fermi energy between a random solid solution and the predicted structure with SRO. Despite that, the calculated EXAFS spectra does not show enough contrast to discriminate between random and ordered structures. The predicted SRO has an impact on point-defect energetics, electron–phonon coupling and thermodynamic functions and thus, SRO should not be neglected when studying properties of these two alloys

  16. Mineralogical characteristics of the superlarge Quaternary bauxite deposits in Jingxi and Debao counties, western Guangxi, China

    Science.gov (United States)

    Liu, Xuefei; Wang, Qingfei; Zhang, Qizuan; Feng, Yuewen; Cai, Shuhui

    2012-06-01

    In recent decades, more than 0.5 billion tons of ores scattered in the Quaternary laterite in western Guangxi, China have been explored. The ores were derived from a bauxite horizon in Permian via physical break-up and re-sediment process. Utilizing various test methods, i.e., XRD, DTA, TG/DTG, SEM/EDS and EPMA, the mineralogical characteristics of the Quaternary bauxite ores in Jingxi and Debao counties were investigated. XRD was used together with TG/DTG to obtain relatively accurate ore mineral abundance. Diaspore is the major phase, whereas hematite, kaolinite, anatase, chamosite, gibbsite, goethite, illite and rutile are minor. Diaspore is characterized by a small particle size, low degrees of crystallinity and complex chemical composition. Both gibbsite and goethite have a varied particle size, and goethite crystals contain high Al substitution and Si. It is clarified that diaspore, chamosite and anatase were formed in a mildly reduced and alkaline depositional environment in Permian, while gibbsite, hematite, goethite and part kaolinite were precipitated from Al3+-, Si4+- and Fe3+-enriched solutions within an Quaternary oxidized environment. The ions Al3+, Si4+ and Fe3+ are mostly released from chamosite in its dissolution process. The different physicochemical conditions between the Permian depositional and the Quaternary weathering periods resulted in a complex mineral assemblage in the Quaternary bauxite.

  17. Geochemical signatures of tephras from Quaternary Antarctic Peninsula volcanoes

    OpenAIRE

    Kraus,Stefan; Kurbatov,Andrei; Yates,Martin

    2013-01-01

    In the northern Antarctic Peninsula area, at least 12 Late Plelstocene-Holocene volcanic centers could be potential sources of tephra layers in the region. We present unique geochemical fingerprints for ten of these volcanoes using major, trace, rare earth element, and isotope data from 95 samples of tephra and other eruption products. The volcanoes have predominantly basaltic and basaltic andesitic compositions. The Nb/Y ratio proves useful to distinguish between volcanic centers located on ...

  18. A GIS method for reconstruction of late Quaternary landscapes from isobase data and modern topography

    Science.gov (United States)

    Leverington, David W.; Teller, James T.; Mann, Jason D.

    2002-06-01

    Digital reconstructions of late Quaternary landscapes can be produced using a geographic information system (GIS) method that subtracts interpolated isobase values from modern elevations and bathymetry. The principal utility of the GIS method for reconstructing late Quaternary landscapes is in the relative ease and rapidity with which high-resolution, quantitative, and georeferenced databases of paleo-topography can be generated. These databases can be used for many purposes, including the generation of paleo-topographic maps, the estimation of the areas and volumes of individual water bodies and landforms, and the approximation of paleo-shoreline positions. GIS-based estimates of the dimensions of water bodies and landforms can be used to help constrain hydrological and climatic models of the late Quaternary.

  19. Electrometric studies on the stabilities of some ternary and quaternary complexes of lanthanones

    International Nuclear Information System (INIS)

    Yadav, S.S.; Sharma, R.C.

    1994-01-01

    Potentiometric evidences have been cited for the formation of 1:1:1, Ln(III)-PDA-NTA/TCA ternary complexes and 1:1:1:1, Ln(III)-PDA-NTA-TCA quaternary complexes (where, Ln(III)=La(III), Pr(III) and Nd(III); PDA pyridine-2, 6-dicarboxylic acid, NTA = nitrilotriacetic acid and TCA thiophene-e-carboxylic acid). The formation constants log K MLL and K MLLL for the resulting ternary and quaternary complexes respectively have been evaluated at constant ionic strength (μ = 0.1 M KNO 3 ) and temperature (298± 1 K). The calculated values of stability constants in terms of metal ions have been found both in ternary and quaternary complexes as La(III) 0 indicated the spontaneous nature of the reaction and the bond formed in the resulting complexes. (author). 13 refs., 2 figs., 2 tabs

  20. Study of ternary and quaternary spontaneous fission of 252Cf with the NESSI detector

    International Nuclear Information System (INIS)

    Tishchenko, V.G.; Jahnke, U.; Herbach, C.M.; Hilscher, D.

    2002-11-01

    Ternary and quaternary spontaneous decay of 252 Cf was studied with the NESSI detector, a combination of two 4π detectors for charged particles, neutrons and γ-rays. The applied method of particle identification by measuring the energies and relative time-of-flights of the decay products is shown to be very effective for the study of rare decay modes. The energy and angular distributions of the decay products, the associated neutron multiplicities, the total energy of the prompt γ-radiation as well as correlations between the various observables were measured for the first time in a single full-scale experiment. The characteristics of ternary fission known from previous investigations are confirmed in the frame of a methodically independent experiment. Preliminary estimates of the quaternary fission yield are presented. An attempt is made to determine the mechanism of quaternary fission. (orig.)

  1. NUCLEOPHILIC SUBSTITUTION REACTION OF CYANIDE AND METHOXYDE IONS TO QUATERNARY MANNICH BASE FROM VANILLIN

    Directory of Open Access Journals (Sweden)

    Bambang Purwono

    2010-06-01

    Full Text Available The nucleophilic substitution reaction to quaternary Mannich base from vanillin has been investigated. Mannich reaction to vanillin was carried out by refluxing mixture of vanillin, formaldehyde and dimethyl amine. Quaternary ammonium halide salt was obtained from reaction of Mannich vanillin base with methyl iodide in THF solvents and yielded 93.28 %. Nucleophilic substituion to the halide salts with cyanide nucleophile produced 4-hidroxy-3-methoxy-5-(cyanomethylbenzaldehyde in 54.39% yield. Reaction with methoxyde ion yielded 4-hydroxy- 3-methoxy-5-(methoxy -methylbenzaldehyde in 67.80% yield. The nucleophilic substitution reaction showed that trimethylamino substituent of quaternary Mannich base can act as a good leaving group on nucleophilic substitution reactions. Keywords: Mannich reaction, vanillin, nucleophilic substitution

  2. NUCHLEOPHILIC SUBSTITUTION REACTION OF CYANIDE AND METHOXYDE IONS TO QUATERNARY MANNICH BASE FROM VANILLIN

    Directory of Open Access Journals (Sweden)

    Bambang Purwono

    2010-06-01

    Full Text Available The nucleophilic substitution reaction to quaternary Mannich base from vanillin has been investigated. Mannich reaction to vanillin was carried out by refluxing mixture of vanillin, formaldehyde and dimethyl amine. Quaternary ammonium halide salt was obtained from reaction of Mannich vanillin base with methyl iodide in THF solvents and yielded  93.28%. Nucleophilic substituion to the halide salts with cyanide nucleophile produced 4-hidroxy-3-methoxy-5-(cyanomethylbenzaldehyde in 54.39% yield, with methoxyde ion obtained  4-hidroxy- 3-methoxy-5-(methoxy-methyl-benzaldehide in 67.80% yield. The nucleophilic substitution reaction showed that substituen of trimethylamino quaternary Mannich base can act as a good leaving on nucleophilic reaction substitutions.   Keywords: Mannich Reaction, Vanillin, nucleophilic substitution.

  3. The determination of B and Sr isotopes of quaternary biologic fossils in Yanghuzhuang Yanqing basin and their living environment

    International Nuclear Information System (INIS)

    Xiao Yingkai; Xiao Jun; Zhao Zhiqi; He Maoyong; Li Shizhen

    2007-01-01

    The B and Sr isotopic compositions of early Quaternary biologic fossils in Yanghuzhuang and living bivalves in Weishui river were measured. Comparing with the data of marine foraminifer, the results show a non-marine living environment for these foraminifers lived in early Quaternary in Yanghuzhuang, Yanqing; Basin. (authors)

  4. Formal Quaternary stratigraphy—What do we expect and need?

    Science.gov (United States)

    Shackleton, N. J.

    2006-12-01

    At the start of my INQUA career a reasonable target for the long-term development of Quaternary stratigraphy was the construction of a table that listed a number (perhaps fewer than a dozen, perhaps more) of "stages" for each of the chief regions of the Earth, and which reliably indicated how these stages should be correlated from region to region. A second target was to estimate ages for the stage boundaries. Finally, some workers may have looked towards a series of "global stages" with the hope that these would be defined in their own region rather than in the Alps. For some researchers the target has not changed, nor does its attainment appear much closer. However, there are now many whose requirement is that we create time-series of environmental and climatic change with ever-increasing temporal resolution, along with correlation lines that are precise enough to permit global synoptic reconstruction. Funding for this research is justified partly on the grounds that it will give us increased confidence in our ability to forecast climatic change during the next century. Hence, far from only being of academic interest, long-term planning of energy-based economies indirectly depends upon it. There is a danger that some excellent research by members of the INQUA community becomes marginalized because the stratigraphic framework through which the research is communicated does not meet modern requirements. Oxygen isotope stratigraphy as it was quasi-formalized by Shackleton and Opdyke (1973 and 1976) only applies to marine sediments containing Foraminifera suitable for oxygen isotope analysis. On the other hand there can be no doubt that as an informal standard means of communication, oxygen isotope stratigraphy has been incredibly valuable even in settings where it is very hard to justify its use. Formal stratigraphy is intended to enable precise communication (in research publications and in maps) and I believe that in this regard there is more to be gained by

  5. Pulsed IRSL: A stable and fast bleaching luminescence signal from feldspar for dating Quaternary sediments

    DEFF Research Database (Denmark)

    Tsukamoto, Sumiko; Kondo, Reisuke; Lauer, Tobias

    2017-01-01

    to measurement temperature), continuous wave (CW) pIRIR225 and pIRIR290 signals, as well as the two IR50 signals measured as a part of the pIRIR protocols. This comparison is carried out for 3 samples taken from Late Quaternary fluvial sediments, which have independent age estimates from radiocarbon dating......Elevated temperature post-infrared infrared stimulated luminescence (post-IR IRSL; pIRIR) dating method using feldspar has led to a significant advancement in dating Quaternary sediments, as this signal has been shown to be stable on geological time scales. In comparison to the conventional IRSL...

  6. Quaternary oxides CaABB1O7 of zirconolite crystal structure

    International Nuclear Information System (INIS)

    Belyaev, I.N.; Aver'yanova, L.N.; Lopatin, S.S.

    1983-01-01

    Formation of quaternary oxides CaABB'O 7 of the composition at A=Ti, Zr, Hf, Sn, B=Al, Ga, Cr, Fe, In, B'=Sb, Nb, Ta is studied. Crystal zirconolite structure has been found in twelve samples containing gallium, ferrum (3) titanium, zirconium, hafnium, niobium, tantalum and antimony (5). In the cases, when A=Sn, B=Al quaternary oxides of the above composition are not formed. It is shown that zirconolite structure stability depends not only on cation dimensions but also on their electron structure

  7. A major change in precipitation gradient on the Chinese Loess Plateau at the Pliocene-Quaternary boundary

    Science.gov (United States)

    Peng, Wenbin; Nie, Junsheng; Wang, Zhao; Qiang, Xiaoke; Garzanti, Eduardo; Pfaff, Katharina; Song, Yougui; Stevens, Thomas

    2018-04-01

    Spatiotemporal variations in East Asian Monsoon (EAM) precipitation during the Quaternary have been intensively studied. However, spatial variations in pre-Quaternary EAM precipitation remain largely uninvestigated, preventing a clear understanding of monsoon dynamics during a warmer climatic period. Here we compare the spatial differences in heavy mineral assemblages between Quaternary loess and pre-Quaternary Red Clay on the Chinese Loess Plateau (CLP) to analyze spatial patterns in weathering. Prior studies have revealed that unstable hornblende is the dominant (∼50%) heavy mineral in Chinese loess deposited over the past 500 ka, whereas hornblende content decreases to initiated since ∼2.7 Ma, preventing hornblende dissolution to amounts change in climatic patterns at ∼2.7 Ma to decreased northward moisture transportation associated with Northern Hemisphere glaciation and cooling in the Quaternary. This study therefore demonstrates the potential usefulness of employing heavy mineral analysis in both paleoclimatic and paleooceanographic reconstructions.

  8. IRASM Center

    International Nuclear Information System (INIS)

    Ponta, C.C.; Moise, I.V.; Georgescu, R.; Ene, M.

    2003-01-01

    IRASM is a national center for radiation processing developed around an industrial Co60 gamma irradiator. Being a department in an R and D national institute, IRASM Center is dealing with radiation treatment, pre/post microbiological control, validation of irradiation sterilization, detection of irradiated foodstuffs. Training is available for operators of new irradiation facilities focused on radiation technologies, dosimetry, sterilization, food treatment, conservation by irradiation of cultural heritage, quality assurance. Expertise on proper choosing the plastics for packaging versus dose is offered to the potential clients. IRASM Center is also involved in interdisciplinary applied research like chitosan treatment, sterile male technique or implementation of irradiation step in production of pharmaceuticals. All important activities: irradiation treatment, dosimetry, microbiology, detection of irradiated food, radioprotection, nuclear safety, physical protection. are performed in accordance with the proper standards in the frame of a certified quality management system. In this way Co60 industrial sources, a byproduct of certain nuclear power plants like Candu type, appear to be the key of a large technical and R and D domain. (authors)

  9. Paleoclimatic Comparisons Between Three Late Quaternary Amazonian Lacustrine Records

    Science.gov (United States)

    Cordeiro, R. C.; Martins, G. S.; Fontes, D.; Turcq, B.; Sifeddine, A.; Seoane, J. S.; Conceição, M. G.; Barbosa, M.; Rodrigues, R. A.; Moreira, L.

    2012-12-01

    In recent years many records made in the cores of ice has shown significant changes in temperature associated with changes in atmospheric composition. The most notable changes occur between the glacials and interglacials cycles. Climatic changes in tropical areas during the global climatic changes is highly debatable. Even today, there are many controversies about the extent of the occurrence of dry weather in the Amazon during glacial periods. In the region of São Gabriel da Cachoeira, polynic diagram of Lagoa da Pata showed that vegetation remained with elements of forest trees, with replacement of elements of cold weather during the last glacial. In Carajás were observed substitution forest to savannah, during the last glacial. We present here a comparison of organic and inorganic geochemical sediment record of tree distinct Amazonian sectors: Morro dos Seis Lagos (AM) is located at 0°17‧9.68″ N and 66°40‧36.18″ W (Lagoa da Pata, LPT V core position) located in the forested upper Rio Negro basin in humid climate area (~3000 mm/yr), Carajás Region at 5°50‧ to 6°35‧ S and 49°30‧ to 52°00‧ situated 800 m high in lateritic crust in south eastern Amazonia (1800mm/yr) and São Benedito Region (PA) at 9°7'0.87"S and 56°16'0.00"W (Lago do Saci, Sac01/05 core position) in south Amazonia with a mean precipitation as Carajás around 1800 mm/yr. A comparison of these records reveals important changes in the environmental history of the Amazonian hydrological regime during the late Quaternary. The results of geochemical analyses reveal three hydrological and climatic regimes from 50,000 cal yr BP until the present. The first phase, between 50,000 until ~25,000 cal yr BP, was characterized by relatively high lake level as suggested by high organic carbon values in Lagoa da Pata and Carajás principally in the beginning of the period. In Saci Lake in the beginning of the record (35,500 cal yr BP) high values of TOC were observed relatively to last

  10. Late Quaternary Megafaunal Extinctions in Northern Eurasia: Latest Results

    Science.gov (United States)

    Stuart, Anthony

    2010-05-01

    Anthony J. Stuart1 & Adrian M. Lister2 1 Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK. Email: tony.s@megafauna.org.uk 2 Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK. Email: a.lister@nhm.ac.uk. The global extinction of many spectacular species of megafauna (large terrestrial mammals, together with a few large reptiles and birds) within the last c. 50,000 years (Late Quaternary) has been attributed on the one hand to ‘overkill' by human hunters and on the other to environmental change. However, in spite of more than half a century of active interest and research the issue remains unresolved, largely because there are insufficient dated records of megafaunal species for most parts of the world. Northern Eurasia is an especially fruitful region in which to research megafaunal extinctions as it has a wealth of megafaunal material and crucially most extinctions occurred well within the range of radiocarbon dating. Our approach, in a series of projects over the last decade funded by the UK Natural Environment Research Council (NERC), involves amassing radiocarbon dates made directly on megafaunal material from across the entire region: a) by submitting a substantial number of samples (so far c. 500 dates) for AMS dating at Oxford (ORAU); b) obtaining AMS dates from colleagues working on aDNA projects; and c) carefully screening (‘auditing') dates from the literature. The dates (calibrated using OxCal) are plotted as time-sliced maps and as chronological/geographical charts. In our previous work we targeted a range of extinct species from Northern Eurasia: woolly mammoth, woolly rhinoceros, giant deer, cave bear (in collaboration with Martina Pacher), cave lion, and spotted hyaena (which survives today only in Sub-Saharan Africa). By this means we have established a reliable chronology for these extinctions which we are able to compare with the climatic, vegetational and

  11. Coating of adenovirus type 5 with polymers containing quaternary amines prevents binding to blood components

    Czech Academy of Sciences Publication Activity Database

    Šubr, Vladimír; Kostka, Libor; Selby-Milic, T.; Fisher, K.; Ulbrich, Karel; Seymour, W.; Carlisle, R. C.

    2009-01-01

    Roč. 135, č. 2 (2009), s. 152-158 ISSN 0168-3659 R&D Projects: GA AV ČR KJB400500803 EU Projects: European Commission(XE) 512087 - GIANT Institutional research plan: CEZ:AV0Z40500505 Keywords : quaternary ammonium * HPMA * adenovirus Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.949, year: 2009

  12. Diverse range dynamics and dispersal routes of plants on the Tibetan Plateau during the late Quaternary.

    Directory of Open Access Journals (Sweden)

    Haibin Yu

    Full Text Available Phylogeographical studies have suggested that several plant species on the Tibetan Plateau (TP underwent recolonization during the Quaternary and may have had distinct range dynamics in response to the last glacial. To further test this hypothesis and locate the possible historical dispersal routes, we selected 20 plant species from different parts of the TP and modeled their geographical distributions over four time periods using species distribution models (SDMs. Furthermore, we applied the least-cost path method together with SDMs and shared haplotypes to estimate their historical dispersal corridors. We identified three general scenarios of species distribution change during the late Quaternary: the 'contraction-expansion' scenario for species in the northeastern TP, the 'expansion-contraction' scenario for species in the southeast and the 'stable' scenario for widespread species. During the Quaternary, we identified that these species were likely to recolonize along the low-elevation valleys, huge mountain ranges and flat plateau platform (e.g. the Yarlung Zangbo Valley and the Himalaya. We inferred that Quaternary cyclic glaciations along with the various topographic and climatic conditions of the TP could have resulted in the diverse patterns of range shift and dispersal of Tibetan plant species. Finally, we believe that this study would provide valuable insights for the conservation of alpine species under future climate change.

  13. Phytolith analysis in fluvial quaternary sediment (San Salvador and Palmar formation) Uruguay river and Argentina eastern

    International Nuclear Information System (INIS)

    Patterer, N.; Passeggi, E.; Zucol, A.; Brea, M.; Krohling, D.

    2012-01-01

    This work is about two microfossils fluvial units deposited by the Uruguay river during the Quaternary. These are San Salvador and Palmar formation (Plio-Pleistocene - Upper Pleistocene).The Palmar formation is a band of 4-15 km along the right bank of the Uruguay river outcropping from the eastern provinces of Corrientes and Entre Rios, to Concepcion del Uruguay

  14. Late Quaternary vegetation and glacial history in the St. Lawrence Lowlands, Canada

    NARCIS (Netherlands)

    Lasalle, Pierre

    1966-01-01

    This paper presents data of various kinds concerning the Quaternary geology of the St. Lawrence Lowlands: pollen diagrams, C14 dates, and diatom floras. These data show that the highest parts of the St. Lawrence Lowlands were already deglaciated more than 12,000 years ago, as appears from the

  15. Quaternary association in β-prism I fold plant lectins: Insights from X ...

    Indian Academy of Sciences (India)

    ... Refresher Courses · Symposia · Live Streaming. Home; Journals; Journal of Biosciences; Volume 36; Issue 5. Quaternary association in -prism I fold plant lectins: Insights from X-ray crystallography, modelling and molecular dynamics. Alok Sharma Mamannamana Vijayan. Articles Volume 36 Issue 5 December 2011 pp ...

  16. Towards dating Quaternary sediments using the quartz Violet Stimulated Luminescence (VSL) signal

    DEFF Research Database (Denmark)

    Ankjærgaard, C.; Jain, Mayank; Wallinga, J.

    2013-01-01

    Quaternary sediments using the violet (402 nm) stimulated luminescence (VSL) signal of quartz.We develop and test a new post-blue VSL single aliquot regenerative dose dating protocol, and demonstrate that the VSL signal originates from a deep trap at about 1.9 eV with a thermal lifetime of 1011 years at 10...

  17. Variability of East Asian winter monsoon in Quaternary climatic extremes in North China.

    NARCIS (Netherlands)

    Lu, H.; van Huissteden, J.; Zhou, J.

    2000-01-01

    In order to examine high-frequency variations of East Asian winter monsoon in Quaternary climate extremes, two typical loess-paleosol sequences in the Chinese Loess Plateau were investigated. Sandy layers in the loess deposits, the "Upper sand" and "Lower sand" (layers L9 and L15, respectively),

  18. Synthesis and Spectroscopic Characterisation of N-Alkyl Quaternary Ammonium Salts Typical Precursors of Cyanines

    Directory of Open Access Journals (Sweden)

    P. Almeida

    2002-03-01

    Full Text Available The synthesis and spectroscopic characterisation of some representative N-alkylsubstituted quaternary ammonium salts derived from benzothiazole, benzoxazole, benzoselenazole, indole and quinoline are described. These heterocyclic salts, bearing an activated methyl group in the 2-position in relation to the nitrogen atom and N-methyl, -pentyl, -hexyl and -decyl chains, are typical precursors of cyanine dyes.

  19. Complete genome sequence of Campylobacter jejuni RM1246-ERRC that exhibits resistance to Quaternary Ammonium Compounds

    Science.gov (United States)

    Campylobacter jejuni strain RM1246-ERRC is a clinical isolate. In laboratory experiments RM1246-ERRC exhibited resistance to the antimicrobial effects of quaternary ammonium compounds (QACs) when compared to other C. jejuni strains. The chromosome of RM1246-ERRC was determined to be 1,659,694 bp w...

  20. High order quaternary arrangement confers increased structural stability to Brucella Spp. lumazine synthase

    Energy Technology Data Exchange (ETDEWEB)

    Zylberman, V.; Craig, P.O.; Klinke, S.; Cauerhff, A.; Goldbaum, F.A. [Instituto Leloir, Buenos Aires (Argentina); Braden, B.C. [Bowie State Univ., Maryland (United States)

    2004-07-01

    The penultimate step in the pathway of riboflavin biosynthesis is catalyzed by the enzyme lumazine synthase (LS). One of the most distinctive characteristics of this enzyme is the structural quaternary divergence found in different species. The protein exists as pentameric and icosahedral forms, built from practically the same structural monomeric unit. The pentameric structure is formed by five 18 kDa monomers, each extensively contacting neighboring monomers. The icosahedral structure consists of 60 LS monomers arranged as twelve pentamers giving rise to a capsid exhibiting icosahedral 532 symmetry. In all lumazine synthases studied, the topologically equivalent active sites are located at the interfaces between adjacent subunits in the pentameric modules. The Brucella spp. lumazine synthase (BLS) sequence clearly diverges from pentameric and icosahedral enzymes. This unusual divergence prompted to further investigate on its quaternary arrangement. In the present work, we demonstrate by means of solution Light Scattering and X-ray structural analyses that BLS assembles as a very stable dimer of pentamers representing a third category of quaternary assembly for lumazine synthases. We also describe by spectroscopic studies the thermodynamic stability of this oligomeric protein, and postulate a mechanism for dissociation/unfolding of this macromolecular assembly. The higher molecular order of BLS increases its stability 20 deg C compared to pentameric lumazine synthases. The decameric arrangement described in this work highlights the importance of quaternary interactions in the stabilization of proteins. (author)

  1. Poly(3,4-ethylenedioxythiophene)-Poly(styrenesulfonate) Interlayer Insertion Enables Organic Quaternary Memory.

    Science.gov (United States)

    Cheng, Xue-Feng; Hou, Xiang; Qian, Wen-Hu; He, Jing-Hui; Xu, Qing-Feng; Li, Hua; Li, Na-Jun; Chen, Dong-Yun; Lu, Jian-Mei

    2017-08-23

    Herein, for the first time, quaternary resistive memory based on an organic molecule is achieved via surface engineering. A layer of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) was inserted between the indium tin oxide (ITO) electrode and the organic layer (squaraine, SA-Bu) to form an ITO/PEDOT-PSS/SA-Bu/Al architecture. The modified resistive random-access memory (RRAM) devices achieve quaternary memory switching with the highest yield (∼41%) to date. Surface morphology, crystallinity, and mosaicity of the deposited organic grains are greatly improved after insertion of a PEDOT-PSS interlayer, which provides better contacts at the grain boundaries as well as the electrode/active layer interface. The PEDOT-PSS interlayer also reduces the hole injection barrier from the electrode to the active layer. Thus, the threshold voltage of each switching is greatly reduced, allowing for more quaternary switching in a certain voltage window. Our results provide a simple yet powerful strategy as an alternative to molecular design to achieve organic quaternary resistive memory.

  2. Late Quaternary millennial-scale variability in pelagic aragonite preservation off Somalia.

    NARCIS (Netherlands)

    Klöcker, R.; Ganssen, G.M.; Jung, S.J.A.; Kroon, D.; Henrich, R.

    2006-01-01

    In order to better understand Late Quaternary pelagic aragonite preservation in the western Arabian Sea we have investigated a high-resolution sediment core 905 off Somalia. Pteropod preservation is enhanced in times of reduced monsoon-driven productivity, indicated by low amounts of C

  3. Dynamic covalent chemistry enables formation of antimicrobial peptide quaternary assemblies in a completely abiotic manner

    Science.gov (United States)

    Reuther, James F.; Dees, Justine L.; Kolesnichenko, Igor V.; Hernandez, Erik T.; Ukraintsev, Dmitri V.; Guduru, Rusheel; Whiteley, Marvin; Anslyn, Eric V.

    2018-01-01

    Naturally occurring peptides and proteins often use dynamic disulfide bonds to impart defined tertiary/quaternary structures for the formation of binding pockets with uniform size and function. Although peptide synthesis and modification are well established, controlling quaternary structure formation remains a significant challenge. Here, we report the facile incorporation of aryl aldehyde and acyl hydrazide functionalities into peptide oligomers via solid-phase copper-catalysed azide-alkyne cycloaddition (SP-CuAAC) click reactions. When mixed, these complementary functional groups rapidly react in aqueous media at neutral pH to form peptide-peptide intermolecular macrocycles with highly tunable ring sizes. Moreover, sequence-specific figure-of-eight, dumbbell-shaped, zipper-like and multi-loop quaternary structures were formed selectively. Controlling the proportions of reacting peptides with mismatched numbers of complementary reactive groups results in the formation of higher-molecular-weight sequence-defined ladder polymers. This also amplified antimicrobial effectiveness in select cases. This strategy represents a general approach to the creation of complex abiotic peptide quaternary structures.

  4. Quaternary geology and geomorphology of the lower Deschutes River Canyon, Oregon.

    Science.gov (United States)

    Jim E. O' Connor; Janet H. Curran; Robin A. Beebee; Gordon E. Grant; Andrei. Sarna-Wojcicki

    2003-01-01

    The morphology of the Deschutes River canyon downstream of the Pelton-Round Butte dam complex is the product of the regional geologic history, the composition of the geologic units that compose the valley walls, and Quaternary processes and events. Geologic units within the valley walls and regional deformation patterns control overall valley morphology. Valley bottom...

  5. Late Quaternary sedimentary processes and ocean circulation changes at the Southeast Greenland margin

    NARCIS (Netherlands)

    Kuijpers, A.; Troelstra, S.R.; Prins, M.A.; Linthout, K.; Akhmetzhanov, A.; Bouryak, S.; Bachmann, M.F.; Lassen, S.; Rasmussen, S.; Jensen, J.B.

    2003-01-01

    A study has been made of late Quaternary depositional processes and bottom current activity on the Southeast Greenland margin, using seismic, sub-bottom profiling and deep-tow side-scan sonar data as well as sediment core information. The seabed data demonstrate the occurrence of strong, southerly

  6. Quaternary association in β-prism I fold plant lectins: Insights from X ...

    Indian Academy of Sciences (India)

    Quaternary association in β-prism I fold plant lectins: Insights from X-ray crystallography, modelling and molecular dynamics. ALOK SHARMA and MAMANNAMANA VIJAYAN. J. Biosci. 36(5), December 2011, 793–808, © Indian Academy of Sciences. Supplementary Material http://www.ias.ac.in/jbiosci. Supplementary ...

  7. A Quaternary Polybenzimidazole Membrane for Intermediate Temperature Polymer Electrolyte Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Xu, C.; Scott, K.; Li, Qingfeng

    2013-01-01

    A quaternary ammonium polybenzimidazole (QPBI) membrane was synthesized for applications in intermediate temperature (100–200 °C) hydrogen fuel cells. The QPBI membrane was imbibed with phosphoric acid to provide suitable proton conductivity. The proton conductivity of the membrane was 0.051 S cm–1...

  8. Late Quaternary stratigraphy and depositional history of the Long Island Sound basin

    Science.gov (United States)

    Lewis, Ralph S.; Stone, Janet R.

    1991-01-01

    The stratigraphy of Late Quaternary geologic units beneath Long Island Sound (LIS) is interpreted from 3,500 km of high-resolution, seismic-reflection profiles supplemented by vibracore data. Knowledge gained from onshore regional geologic studies and previous offshore investigations is also incorporated in these interpretations.

  9. External controls on Quaternary fluvial incision and terrace formation at the Segre River, Southern Pyrenees

    NARCIS (Netherlands)

    Stange, K.M.; van Balen, R.T.; Vandenberghe, J.; Peña, J.L.; Sancho, C.

    2013-01-01

    Focusing on climatic- and structural (tectonic) controls, we aim to determine their relative importance for the (Pliocene to Quaternary) fluvial landscape evolution in the Southern Pyrenees foreland. We investigate the Segre River, which is one of the major streams of the Southern Pyrenees that

  10. Epoxidation of Alkenes with Aqueous Hydrogen Peroxide and Quaternary Ammonium Bicarbonate Catalysts

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Kegnæs, Søren

    2013-01-01

    A range of solid and liquid catalysts containing bicarbonate anions were synthesised and tested for the epoxidation of alkenes with aqueous hydrogen peroxide. The combination of bicarbonate anions and quaternary ammonium cations opens up for new catalytic systems that can help to overcome...

  11. Tertiary and Quaternary sedimentation in a part of the Duero Basin Palencia, (Spain)

    NARCIS (Netherlands)

    Mabesoone, J.M.

    1959-01-01

    Sediments in the foreland of a mountain chain are sometimes suited to reconstitute the conditions in these mountains at the time of deposition of the sediments. The present study gives the results of a sedimentological investigation of the Tertiary and Quaternary deposits in a part of the Duero

  12. Late quaternary sea level changes of Gabes coastal plain and shelf ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 125; Issue 1. Late quaternary sea level changes of ... and the fluvial discharges are consistent. Actual morphologic trend deduced from different environment coasts (sandy coasts, sea cliffs and tidal flat) is marked by accumulation of marine sands and progradation.

  13. Towards dating Quaternary sediments using the quartz Violet Stimulated Luminescence (VSL) signal

    NARCIS (Netherlands)

    Ankjaergaard, C.; Jain, M.; Wallinga, J.

    2013-01-01

    Quartz optically stimulated luminescence (OSL) dating is widely used to determine the time of deposition and burial of Late Quaternary sediments. Application of the method is usually limited to the past 150,000 years due to early saturation of the OSL signal. Here we explore the potential to date

  14. A study of Quaternary structures in the Qom region, West Central Iran

    Science.gov (United States)

    Babaahmadi, A.; Safaei, H.; Yassaghi, A.; Vafa, H.; Naeimi, A.; Madanipour, S.; Ahmadi, M.

    2010-12-01

    West Central Iran comprises numerous Quaternary faults. Having either strike-slip or thrust mechanisms, these faults are potentially active and therefore capable of creating destructive earthquakes. In this paper, we use satellite images as well as field trips to identify these active faults in the Qom region. The Qom and Indes faults are the main NW-trending faults along which a Quaternary restraining step-over zone has formed. Kamarkuh, Mohsen Abad, and Ferdows anticlines are potentially active structures that formed in this restraining step-over zone. There are some thrusts and anticlines, such as the Alborz anticline and Alborz fault, which are parallel to strike-slip faults such as the Qom fault, indicating deformation partitioning in the area. In addition to NW-trending structures, there is an important NE-trending fault known as the Qomrud fault that has deformed Quaternary deposits and affected Kushk-e-Nosrat fault, Alborz anticline, and Qomrud River. The results of this study imply that the major Quaternary faults of West Central Iran and their restraining step-over zones are potentially active.

  15. Effects of chlorine, iodine, and quaternary ammonium compound disinfectants on several exotic disease viruses.

    Science.gov (United States)

    Shirai, J; Kanno, T; Tsuchiya, Y; Mitsubayashi, S; Seki, R

    2000-01-01

    The effects of three representative disinfectants, chlorine (sodium hypochlorite), iodine (potassium tetraglicine triiodide), and quaternary ammonium compound (didecyldimethylammonium chloride), on several exotic disease viruses were examined. The viruses used were four enveloped viruses (vesicular stomatitis virus, African swine fever virus, equine viral arteritis virus, and porcine reproductive and respiratory syndrome virus) and two non-enveloped viruses (swine vesicular disease virus (SVDV) and African horse sickness virus (AHSV)). Chlorine was effective against all viruses except SVDV at concentrations of 0.03% to 0.0075%, and a dose response was observed. Iodine was very effective against all viruses at concentrations of 0.015% to 0.0075%, but a dose response was not observed. Quaternary ammonium compound was very effective in low concentration of 0.003% against four enveloped viruses and AHSV, but it was only effective against SVDV with 0.05% NaOH. Electron microscopic observation revealed the probable mechanism of each disinfectant. Chlorine caused complete degeneration of the viral particles and also destroyed the nucleic acid of the viruses. Iodine destroyed mainly the inner components including nucleic acid of the viruses. Quaternary ammonium compound induced detachment of the envelope of the enveloped viruses and formation of micelle in non-enveloped viruses. According to these results, chlorine and iodine disinfectants were quite effective against most of the viruses used at adequately high concentration. The effective concentration of quaternary ammonium compound was the lowest among the disinfectants examined.

  16. Map showing thickness of saturated Quaternary deposits, Sugar House quadrangle, Salt Lake County, Utah, February 1972

    Science.gov (United States)

    Mower, R.W.

    1973-01-01

    Saturated Quaternary deposits in the Sugar Horse quadrangle supply significant quantities of water to wells from which water is withdrawn for domestic, municipal, industrial, and irrigation uses. The deposits consist of clay, silt, sand, and gravel; individual beds range from a few inches to several tens of feet thick. The principal aquifer, which is almost completely within the Quaternary deposits, supplied about 4 percent, or 9,000 acre-feet, of the municipal and industrial water used annually in Salt Lake County during 1964-68.As a general rule, more water is stored and more water will be yielded to a well where aquifers are thicker. This map can be used as a general guide to those areas where greatest amounts of water are stored in the aquifer, and where yields to wells may be greater. Local variations in the ability of saturated deposits to transmit water can alter the general relationship between aquifer thickness and yield of wells.The thickness of saturated Quaternary deposits within the area of the Sugar Horse quadrangle ranges from zero to about 650 feet, as shown on the map. The thickest section of these deposits is near the southwestern corner of the quadrangle, and the thinnest section is along the mountain front adjacent to the approximate eastern limit of saturated Quaternary deposits.The thickness of saturated Quaternary deposits shown on this map is based on drillers’ logs for 55 deep wells (which show the thickness of the Quaternary deposits) and on water-level measurements made in February 1972 in wells in unconfined shallow aquifers.Reports in the following list of selected references contain other information about the saturated Quaternary deposits in this and adjacent parts of Jordan Valley, Utah. The basic-data reports and releases contain well logs, water-level measurements, and other types of basic ground-water data. The interpretive repots contain discussions of the occurrence of ground water, tests to determine hydraulic properties of

  17. Comparative Paleomagnetic Study of the Quaternary-Pliocene Sedimentation Rates in the Arctic Basin: First Results

    Science.gov (United States)

    Elkina, D.; Piskarev, A.

    2017-12-01

    Accurate dating of marine sediments from the Arctic Basin continues to remain a subject of great debates over the last decades. Due to the lack of adequate materials for biostratigraphy, and isotope analyses, paleomagnetic reconstructions came on line here but still yielded ambivalent interpretations. Moreover, sedimentation rates, estimated for isolated morphological features in the Arctic Ocean, are often extended to the whole Basin and, therefore, lead to significant approximations of the sedimentation pattern distribution. Paleomagnetic study of two sediment cores up to 8 meter long, collected at the Mendeleev Rise, and the Lomonosov Ridge, have provided the opportunity to compare sedimentation regimes on these two profound structures of the Arctic Basin. Cores PS72/396 and PS87/023 were carried out along the cruises of RV Polarstern at the Mendeleev Rise (Stein et. al, 2010), and the Lomonosov Ridge (Stein, 2015) respectively. Measurements of natural remanent magnetization (NRM) and anhysteretic remanence (ARM) acquisition with the following alternating field (AF) demagnetization were performed on u-channel samples, obtained from the cores, at the Center for Geo-Environmental Research and Modeling (GEOMODEL) of the Research Park, St. Petersburg State University. According to preliminary results, core PS72/396 has shown a change from positive to negative inclinations at ca. 120 cm below sea floor (cmbsf), prevailed up to ca. 360 cmbsf where it gets back to the positive ones. This trend is comparable with some previous paleomagnetic results, conducted on cores from the Mendeleev Rise (Piskarev et al., 2013; Elkina, 2014). In contrast, for core PS87/023, a relevant drop to negative inclinations can be observed only after 330 cmbsf. That could signify a dramatic difference in sedimentation rates between the sites during the Quaternary and Pliocene. Nevertheless, a rather complicated picture of the AF data assumes effects of secondary overprints, having influenced

  18. Quaternary tectonic evolution of the Pamir-Tian Shan convergence zone, Northwest China

    Science.gov (United States)

    Thompson Jobe, Jessica Ann; Li, Tao; Chen, Jie; Burbank, Douglas W.; Bufe, Aaron

    2017-12-01

    The Pamir-Tian Shan collision zone in the western Tarim Basin, northwest China, formed from rapid and ongoing convergence in response to the Indo-Eurasian collision. The arid landscape preserves suites of fluvial terraces crossing structures active since the late Neogene that create fault and fold scarps recording Quaternary deformation. Using geologic and geomorphic mapping, differential GPS surveys of deformed terraces, and optically stimulated luminescence dating, we create a synthesis of the active structures that delineate the timing, rate, and migration of Quaternary deformation during ongoing convergence. New deformation rates on eight faults and folds, when combined with previous studies, highlight the spatial and temporal patterns of deformation within the Pamir-Tian Shan convergence zone during the Quaternary. Terraces spanning 130 to 8 ka record deformation rates between 0.1 and 5.6 mm/yr on individual structures. In the westernmost Tarim Basin, where the Pamir and Tian Shan are already juxtaposed, the fastest rates occur on actively deforming structures at the interface of the Pamir-Tian Shan orogens. Farther east, as the separation between the Pamir-Tian Shan orogens increases, the deformation has not been concentrated on a single structure, but rather has been concurrently distributed across a zone of faults and folds in the Kashi-Atushi fold-and-thrust belt and along the NE Pamir margin, where shortening rates vary on individual structures during the Quaternary. Although numerous structures accommodate the shortening and the locus of deformation shifts during the Quaternary, the total shortening across the western Tarim Basin has remained steady and approximately matches the current geodetic rate of 6-9 mm/yr.

  19. Dimensional Stability of Poplar Wood by Paraffin Emulsion, Quaternary Ammonium and Hydrated Starch using Full-cell Treatment

    Directory of Open Access Journals (Sweden)

    Iraj Mansouryar

    2011-01-01

    In this study, the dimensional stabilization of poplar wood (Populus Alba by applying emulsion of paraffin, quaternary ammonium and starch was investigated. Paraffin at three levels of 0%, 3%, 5%, quaternary ammonium at three levels of 0%, 1.5%, 2.5% and starch at three levels of 0%, 1% and 2% were selected as variables. Some physical characteristics including longitudinal, tangential and radial swelling were determined. Based on the results, for optimizing physical properties, the treatment of 5% paraffin, 0-1.5% quaternary ammonium and 0-1% starch was recommended.

  20. Data without Frontiers - the International Quaternary Map of Europe (IQUAME 2500)

    Science.gov (United States)

    Asch, Kristine

    2017-04-01

    The Federal German Geological Survey (Bundesanstalt für Geowissenschaften und Rohstoffe, BGR) is leading the review of the International Quaternary Map of Europe (IQUAME 2500) and its transformation into a geographical information system (GIS) under the umbrella of the CGMW and INQUA. It is a long-standing policy of BGR to lead international cooperation of European geological survey mapping projects. These particularly include projects under the umbrella of organisations including CGMW, UNESCO, INQUA, EGU and IUGS. The aim of IQUAME 2500 is to build a geological information system (GIS) of Europe's Quaternary geology where relevant information can be retrieved, combined and applied across international boundaries. Cross-border mapping poses specific challenges, in particular data harmonisation, for the presentation of regional geology. Overcoming these obstacles demands international cooperation with national geological survey organisations. Based on the previous BGR & UNESCO co-produced International Quaternary Map of Europe (at a 1 : 2,5 million scale; completed in 1995), revision was begun by BGR in 2011 to review the information available from an international group of experts from European geological survey organisations. This group is supported by an international academic Advisory Board. The work requires re-evaluation and digitization of the 14 paper sheets. For this purpose BGR developed a pragmatic procedure to classify, deliver and combine the reviewed Quaternary data in a harmonized and uniform manner. The project is applying the vocabularies and data model of the EC Directive INSPIRE Directive and is creating additional vocabularies and definitions for necessary features such as geomorphology (with the EMODnet project) and glaciogenic elements. An academic scientific advisory board is overseeing the process. Subjects of the map include: geological boundaries and classifications of Quaternary rocks, extension and boundaries of permafrost, last glacial

  1. Application of quaternary phase diagrams to compound semiconductor processing. Progress report, April 1, 1988--December 31, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Schwartzman, A.

    1988-12-31

    This paper considers the application of quaternary phase diagrams to understanding and predicting the behavior of II-VI thin film interfaces in photovoltaic devices under annealing conditions. Examples, listed in a table, include semiconductor/insulator/semiconductor (SIS) layered structures, II-VI/II-VI and III-V/II-VI epitaxial heterojunctions and oxidation of ternary compounds. Solid solubility is taken into account for quaternary phase diagrams of semiconductor systems. Using free energies of formation, a method to calculate the quaternary phase diagrams was developed. The Ga-As-II-VI and Cd-Te-Zn-O phase diagrams are reviewed as examples of quaternary phase diagrams without and with solid solubility.

  2. Evidences of late quaternary neotectonic activity and sea-level changes along the western continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Veerayya, M.; Thamban, M.; Wagle, B.G.

    The offshore data on sea-level changes along the western margin of India have been reviewed and evidences of Late Quaternary neotectonic activity and subsidence are documented, based on the diagenetic textures of limestones from deeper submarine...

  3. Radiolarian zonation and volcanic ash layers in two Quaternary sediment cores from the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, S.M.

    Radiolarian abundance in two Quaternary sediment cores, collected from the Central Indian Basin, was studied and Nigrini's (1971) and Goll's (1980) zones are recognised. New radiolarian zones Collosphaera orthoconus, Lamprocyrtis nigriniae...

  4. Radiocarbon chronologies and extinction dynamics of the Late Quaternary mammalian megafauna of the Taimyr Peninsula, Russian Federation

    NARCIS (Netherlands)

    MacPhee, RDE; Tikhonov, AN; Mol, D; Maliave, CD; Van der Plicht, H; Greenwood, AD; Flemming, C; Agenbroad, L; MacPhee, Ross D.E.; Tikhonov, Alexei N.; Marliave, Christian de; Greenwood, Alex D.

    This paper presents 75 new radiocarbon dates based on late Quaternary mammal remains recovered from eastern Taimyr Peninsula and adjacent parts of the northern Siberian lowlands, Russian Federation, including specimens of woolly mammoth (Mammuthus primigenius), steppe bison (Bison priscus), muskox

  5. Use of green fluorescent protein labeled non-tuberculous mycobacteria to evaluate the activity quaternary ammonium compound disinfectants and antibiotics

    Directory of Open Access Journals (Sweden)

    Claudia Cortesia

    Full Text Available Abstract Although infections with NonTuberculous Mycobacteria have become less common in AIDS patients, they are important opportunistic infections after surgical procedures, likely because they are ubiquitous and not efficiently killed by many commonly used disinfectants. In Venezuela there have recently been many non-tuberculous mycobacteria soft tissue infections after minor surgical procedures, some apparently related to the use of a commercial disinfectant based on a Quaternary Ammonium Compound. We studied the activity of this and other quaternary ammonium compounds on different non-tuberculous mycobacteria by transforming the mycobacteria with a dnaA-gfp fusion and then monitoring fluorescence to gauge the capacity of different quaternary ammonium compounds to inhibit bacterial growth. The minimum inhibitory concentration varied for the different quaternary ammonium compounds, but M. chelonae and M. abscessus were consistently more resistant than M. smegmatis, and M. terrae more resistant than M. bovis BCG.

  6. MOVPE growth of quaternary (Al,Ga,In)N for UV optoelectronics[Metal Organic Vapor Phase Epitaxy, Ultraviolet

    Energy Technology Data Exchange (ETDEWEB)

    Han, J.; Figiel, J.J.; Petersen, G.A.; Myers, S.M.; Crawford, M.H.; Banas, M.A.; Hearne, S.J.

    2000-07-01

    The authors report the growth and characterization of quaternary AlGaInN. A comparison of photoluminescence (PL), high-resolution x-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) characterizations enables one to explore the contours of constant-PL peak energy and lattice parameter as functions of the quaternary compositions. The observation of room temperature PL emission at 351 nm (with 20% Al and 5% In) renders initial evidence that the quaternary could be used to provide confinement for GaInN (and possibly GaN). AlGaInN/GaInN MQW heterostructures have been grown; both XRD and PL measurements suggest the possibility of incorporating this quaternary into optoelectronic devices.

  7. Clay minerals as palaeomonsoon proxies: Evaluation and relevance to the late Quaternary records from SE Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Thamban, M.; Rao, V.P.

    as palaeoclimatic proxies are evaluated and discussed. Systematic investigations using several sediment cores from the SE Arabian Sea reveal that despite the influence of several complicating factors, variations in clay mineral composition during the late Quaternary...

  8. New insights into the earliest Quaternary environments in the Central North Sea from 3D seismic

    Science.gov (United States)

    Lamb, Rachel; Huuse, Mads; Stewart, Margaret; Brocklehurst, Simon H.

    2014-05-01

    In the past the transition between an unconformable surface in the south to a conformable horizon towards the north has made identification and mapping the base-Quaternary in the central North Sea difficult (Sejrup et al 1991; Gatliff et al 1994). However recent integration of biostratigraphy, pollen analysis, paleomagnetism and amino acid analysis in the Dutch and Danish sectors (Rasmussen et al 2005; Kuhlmann et al 2006) has allowed greater confidence in the correlation to the region 3D seismic datasets and thus has allowed the base-Quaternary to be mapped across the entire basin. The base-Quaternary has been mapped using the PGS MegaSurvey dataset from wells in the Danish Sector along the initially unconformable horizon and down the delta front into the more conformable basin giving a high degree of confidence in the horizon pick. The revised base-Quaternary surface reaches a depth of 1248 ms TWT with an elongate basin shape which is significantly deeper than the traditionally mapped surface. Using RMS amplitudes and other seismic attributes the revised base-Quaternary has been investigated along the horizon and in time slice to interpret the environments of the earliest Quaternary prior to the onset of glaciation. Combined with analysis of aligned elongate furrows over 10 km long, 100 m wide and 100 m deep suggest a deep marine environment in an almost enclosed basin with persistent strong NW-SE bottom currents in the deepest parts. Pockmarks were formed by the escape of shallow gas on the sides of a small delta in the eastern part of the basin. The progradation of large deltas from both the north and south into the basin make up the majority of the deposition of sediment into the basin. Key Words: base-Quaternary; seismic interpretation; paleoenvironments References: Gatliff, R.W, Richards, P.C, Smith, K, Graham, C.C, McCormac, M, Smith, N.J.P, Long, D, Cameron, T.D.J, Evans, D, Stevenson, A.G, Bulat, J, Ritchie, J.D, (1994) 'United Kingdom offshore regional

  9. Enantioselective construction of quaternary N-heterocycles by palladium-catalysed decarboxylative allylic alkylation of lactams

    KAUST Repository

    Behenna, Douglas C.

    2011-12-18

    The enantioselective synthesis of nitrogen-containing heterocycles (N-heterocycles) represents a substantial chemical research effort and resonates across numerous disciplines, including the total synthesis of natural products and medicinal chemistry. In this Article, we describe the highly enantioselective palladium-catalysed decarboxylative allylic alkylation of readily available lactams to form 3,3-disubstituted pyrrolidinones, piperidinones, caprolactams and structurally related lactams. Given the prevalence of quaternary N-heterocycles in biologically active alkaloids and pharmaceutical agents, we envisage that our method will provide a synthetic entry into the de novo asymmetric synthesis of such structures. As an entry for these investigations we demonstrate how the described catalysis affords enantiopure quaternary lactams that intercept synthetic intermediates previously used in the synthesis of the Aspidosperma alkaloids quebrachamine and rhazinilam, but that were previously only available by chiral auxiliary approaches or as racemic mixtures. © 2012 Macmillan Publishers Limited. All rights reserved.

  10. Quaternary geologic map of the Chesapeake Bay 4 degrees x 6 degrees quadrangle, United States

    Science.gov (United States)

    State compilations by Cleaves, Emery T.; Glaser, John D.; Howard, Alan D.; Johnson, Gerald H.; Wheeler, Walter H.; Sevon, William D.; Judson, Sheldon; Owens, James P.; Peebles, Pamela C.; edited and integrated by Richmond, Gerald Martin; Fullerton, David S.; Weide, David L.

    1987-01-01

    The Quaternary Geologic Map of the Chesapeake Bay 4? x 6? Quadrangle was mapped as part of the Quaternary Geologic Atlas of the United States. The atlas was begun as an effort to depict the areal distribution of surficial geologic deposits and other materials that accumulated or formed during the past 2+ million years, the period that includes all activities of the human species. These materials are at the surface of the Earth. They make up the 'ground' on which we walk, the 'dirt' in which we dig foundations, and the 'soil' in which we grow crops. Most of our human activity is related in one way or another to these surface materials that are referred to collectively by many geologists as regolith, the mantle of fragmental and generally unconsolidated material that overlies the bedrock foundation of the continent. The maps were compiled at 1:1,000,000 scale.

  11. Quaternary geology of Vacherie salt dome, north Louisiana salt dome basin. Volume II

    International Nuclear Information System (INIS)

    Kolb, C.R.; Holmes, J.C.; Alford, J.J.

    1983-07-01

    This volume comprises 14 appendices: lineations on Vacherie and Rayburn's domes (1977); possible geomorphic influence of Vacherie salt dome on the Quaternary fluvial geomorphology of Bashaway Creek (1980); remote sensing and analysis of radar imagery (1978); uphole seismic survey at Vacherie salt dome (1977); electrical resistivity survey at Vacherie salt dome (1978); pedologic investigations (1977); ionium-thorium dating of ironstones from terrace deposits, Vacherie salt dome, North Louisiana (1978); grain-shape and grain-surface studies (1981); the terrace concept - Gulf Coastal Plain (1981); interpretation of Quaternary sediments along lines of seismic shot hole (1976); topographic lows above domes (1977); structural significance of topographic lows above North Louisiana salt domes (1981); diagnostic microfossils - Vacherie dome (1978); and development of stratigraphy above Vacherie dome from Cretaceous to Sparta times (1982)

  12. Fossil oribatid mites (Acari, Oribatida) from the Florisbad Quaternary deposits, South Africa

    Science.gov (United States)

    Coetzee, Louise; Brink, James S.

    2003-03-01

    In a pioneer application of acarology to Quaternary fossil-bearing sediments in southern Africa, the oribatid composition in the Florisbad Quaternary sediments was determined and compared to the currently known distribution of those species. Nine species of oribatid mites were recorded in the Holocene aeolian deposits of the third test pit, three species from the Middle Stone Age (MSA) horizon sediments of the third test pit, and thirteen species from the Holocene spring sediments. The Florisbad results indicate a better agreement between the oribatid fauna of the last interglacial MSA horizon of the third test pit and the organic-rich mid-Holocene deposits near the spring than between either of these and early- and late-Holocene aeolian sediments of the third test pit, suggesting some similarity in microsedimentary environments. The majority of the species recorded in the sediments are parthenogenetic and can be regarded as pioneer species.

  13. Polarization encoded all-optical quaternary successor with the help of SOA assisted Sagnac switch

    Science.gov (United States)

    Chattopadhyay, Tanay; Roy, Jitendra Nath

    2011-06-01

    The application of multi-valued (non-binary) signals can provide a considerable relief in transmission, storage and processing of large amount of information in digital signal processing. Optical multi-valued logical operation is an interesting challenge for future optical signal processing where we can expect much innovation. A novel all-optical quaternary successor (QSUC) circuit with the help of semiconductor optical amplifier (SOA)-assisted Sagnac switch is proposed and described. This circuit exploits the polarization properties of light. Different logical states are represented by different polarization state of light. Simulation result confirming described method is given in this paper. Proposed all-optical successor circuit can take an important and significant role in designing of all-optical quaternary universal inverter and modulo arithmetic unit (addition and multiplication).

  14. Antimicrobial cotton containing N-halamine and quaternary ammonium groups by grafting copolymerization

    Science.gov (United States)

    Liu, Ying; Liu, Yin; Ren, Xuehong; Huang, T. S.

    2014-03-01

    The monomer (3-acrylamidopropyl)trimethylammonium chloride (APTMAC) was used to treat cotton fibers by grafting copolymerization. The grafted cotton fabrics were characterized by SEM image and FTIR spectra. The treated samples with quaternary ammonium groups could decrease 96.08% of Staphylococcus aureus and 48.74% of Escherichia coli O157:H7 within 30 min. After chlorination with dilute sodium hypochlorite, the treated cotton fabrics containing both N-halamine and quaternary ammonium groups effectively inactivated 100% (log reduction 5.82) of S. aureus and 100% (log reduction 6.26) of E. coli O157:H7 within 5 min of contact time. The grafting process of cotton fabric has small effect on the thermal stability and tensile strength, which favors the practical application. Compared to the traditional pad-dry-cure method to produce antibacterial materials, the radical grafting copolymerization method occurred in water without any organic solvents involved in the whole treatment.

  15. Predictive and Experimental Approaches for Elucidating Protein–Protein Interactions and Quaternary Structures

    Directory of Open Access Journals (Sweden)

    John Oliver Nealon

    2017-12-01

    Full Text Available The elucidation of protein–protein interactions is vital for determining the function and action of quaternary protein structures. Here, we discuss the difficulty and importance of establishing protein quaternary structure and review in vitro and in silico methods for doing so. Determining the interacting partner proteins of predicted protein structures is very time-consuming when using in vitro methods, this can be somewhat alleviated by use of predictive methods. However, developing reliably accurate predictive tools has proved to be difficult. We review the current state of the art in predictive protein interaction software and discuss the problem of scoring and therefore ranking predictions. Current community-based predictive exercises are discussed in relation to the growth of protein interaction prediction as an area within these exercises. We suggest a fusion of experimental and predictive methods that make use of sparse experimental data to determine higher resolution predicted protein interactions as being necessary to drive forward development.

  16. Earthquake response characteristics of experimental fast reactor 'JOYO' on quaternary ground, (1)

    International Nuclear Information System (INIS)

    Komada, Hiroya; Yoshida, Yasuo; Kataoka, Tetsuyuki

    1987-01-01

    It is important to establish ground surveying and testing methods when large important structures are constructed on quaternary ground. Various methods for surveying and testing from surface ground were carried out at the site of Experimental Fast Reactor 'JOYO' which is deeply embedded in compacted sand and granular quaternary ground. The following methods were mainly carried out. (1) Penetration test: Standard penetration test, Large scale penetration test, Static corn penetration test (2) Surface elastic wave exploration: P.S wave exploration in boring hole, Shallow seismio reflection method, Sonic wave exploration (3) Boring wall pressure test (4) Boring wall shear test (5) Undisturbance core sampling (6) Laboratory dynamic triaxial tests. The reliance of above surveying and testing methods were studied and the improvement in future were clarified. (author)

  17. Biotic response to late Quaternary rapid climate switches in Santa Barbara Basin: Ecological and evolutionary implications

    International Nuclear Information System (INIS)

    Cannariato, K.G.; Kennett, J.P.; Behl, R.J.

    1999-01-01

    Benthic foraminiferal assemblages from Santa Barbara Basin exhibit major faunal and ecological switches associated with late Quaternary millennial- to decadal-scale global climate oscillations. Repeated turnovers of entire faunas occurred rapidly (<40--400 yr) without extinction or speciation in conjunction with Dansgaard-Oeschger shifts in thermohaline circulation, ventilation, and climate, confirming evolutionary model predictions of Roy et al. Consistent faunal successions of dysoxic taxa during successive interstadials reflect the extreme sensitivity and adaptation of the benthic ecosystem to the rapid environmental changes that marked the late Quaternary and possibly other transitional intervals in the history of the Earth's ocean-atmosphere-cryosphere system. These data support the hypothesis that broad segments of the biosphere are well adapted to rapid climate change

  18. Polypeptides with quaternary phosphonium side chains: synthesis, characterization, and cell-penetrating properties.

    Science.gov (United States)

    Song, Ziyuan; Zheng, Nan; Ba, Xiaochu; Yin, Lichen; Zhang, Rujing; Ma, Liang; Cheng, Jianjun

    2014-04-14

    Polypeptides bearing quaternary phosphonium side chains were synthesized via controlled ring-opening polymerization of chlorine-functionalized amino acid N-carboxyanhydride monomers followed by one-step nucleophilic substitution reaction with triethylphosphine. The conformation of the resulting polypeptides can be controlled by modulating the side-chain length and α-carbon stereochemistry. The phosphonium-based poly(l-glutamate) derivatives with 11 σ-bond backbone-to-charge distance adopt stable α-helical conformation against pH and ionic strength changes. These helical, quaternary phosphonium-bearing polypeptides exhibit higher cell-penetrating capability than their racemic and random-coiled analogues. They enter cells mainly via an energy-independent, nonendocytic cell membrane transduction mechanism and exhibit low cytotoxicity, substantiating their potential use as a safe and effective cell-penetrating agent.

  19. Blockfields in Reinheimen Nationalpark, Norway – Neogene weathering remnants or Quaternary periglacial origin?

    DEFF Research Database (Denmark)

    Andersen, Jane Lund; Egholm, David Lundbek; Knudsen, Mads Faurschou

    It is an ongoing debate whether the degree of chemical weathering in mountain regolith can be used to infer a pre-Quaternary formation history (e.g. Strømsøe and Paasche, 2011; Goodfellow 2012). Here we present a new dataset of in-situ produced cosmogenic 10Be and 26Al along with sediment analyses...... rates of landscape evolution of the mountain summit. References Goodfellow B W, 2012. A granulometry and secondary mineral fingerprint of chemical weathering in periglacial landscapes and its application to blockfield origins. Quaternary Science Reviews, 57, 121- 135. Strømsøe J R, Paasche Ø, 2011....... Weathering patterns in high-latitude regolith. Journal of Geophysical Research: Earth Surface, 116 (F3)...

  20. The quaternary architecture of RARβ–RXRα heterodimer facilitates domain–domain signal transmission

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, Vikas; Wu, Dalei; Li, Sheng; Potluri, Nalini; Kim, Youngchang; Rastinejad, Fraydoon

    2017-10-11

    Assessing the physical connections and allosteric communications in multi-domain nuclear receptor (NR) polypeptides has remained challenging, with few crystal structures available to show their overall structural organizations. Here we report the quaternary architecture of multi-domain retinoic acid receptor beta-retinoic X receptor alpha (RAR beta-RXR alpha) heterodimer bound to DNA, ligands and coactivator peptides, examined through crystallographic, hydrogen-deuterium exchange mass spectrometry, mutagenesis and functional studies. The RAR beta ligand-binding domain (LBD) and DNA-binding domain (DBD) are physically connected to foster allosteric signal transmission between them. Direct comparisons among all the multi-domain NRs studied crystallographically to date show significant variations within their quaternary architectures, rather than a common architecture adhering to strict rules. RXR remains flexible and adaptive by maintaining loosely organized domains, while its hetero-dimerization partners use a surface patch on their LBDs to form domain-domain interactions with DBDs.

  1. North American Pika ( Ochotona princeps) as a Late Quaternary Biogeographic Indicator Species

    Science.gov (United States)

    Hafner, David J.

    1993-05-01

    Reevaluation of Quaternary sites of fossil pika ( Ochotona) lends no support for the inference that Nearctic pikas were not restricted to rocky habitat. The saxicolous nature of all widespread, isolated populations of extant Nearctic pikas and their closest Palearctic sister taxa support consideration of O. princeps, and perhaps all Nearctic Quaternary Ochotona , as indicators of cool, mesic, rocky situations. As indicators of rocky microhabitat, fossil remains of O. princeps do not require that the entire region was cool and mesic, but only that suitable rocky microhabitat existed in the vicinity. Use of fossil pika dung alone as indicative of pikas in the immediate community is suspect, as the small, round, and buoyant pellets may be transported downslope by hydraulic flushing of talus habitat. Current local elevational lower limits ( E) of appropriate habitat for paleoecological reconstruction at extralimital fossil sites are predicted by the equation: E(m) = 14087 - (56.6)°N - (82.9)°W.

  2. Mineralogy of auriferous deposits of the quaternary deposits in the San Luis Province, Argentina

    International Nuclear Information System (INIS)

    Karlsson, A.; Ayala, R. . E mail: Karlsson@arnet.com.ar

    2004-01-01

    The objective of this work is to study the mineralogy of the sands and clays of the quaternary deposits in the San Luis Mountain, Argentina. A series of algorithms applied to the sand fraction has permitted to determine sedimentary discontinuities. The two micron fraction of the sediments has been studied by a quantification technique based on X-ray diffraction by means of oriented preparations and run with copper tube. These quaternary silts have received fluvial lateral contributions. The high cristalinidad of non expandibles and fireclay clay show the antique of the silts. The polygenic processes have generated a great variety of clay mineral species like a large quantities of illite and in lesser extend kaolinite and smectites. The illite was probably generated by diagenetic changes. The high cristalinidad of non expandibles and fireclay clay show the antique of the silts [es

  3. Late-Quaternary vegetational history and biostratigraphy of Loktak Lake area of Manipur, India

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Partha; Chanda, S. (Bose Inst., Calcutta (India))

    1988-01-01

    The Quaternary vegetational history, palaeoenvironmental and biostratigraphical work in Manipur, so far, remained unexplored. A subsurface profile, believed to be late-Quaternary, near the Loktak Lake, Manipur, consisting of eight samples, interbedded with black clay, was collected, during the work of Loktak Lake Hydel Power Project. The samples were analyzed palynologically. The result of the analysis reflects the presence of a mixed assemblage of ferns and angiosperms during the period of deposition. The profile may be divided into three pollen zones. The pollen composition of zone I indicates a relatively cool and humid condition. The zone II showed tropical to sub-tropical forest condition and the zone III showed tropical rain forest condition. The last condition still prevails.

  4. Simultaneous adsorption/desorption of quaternary ammonium herbicides by acid vineyard soils

    Science.gov (United States)

    Conde Cid, Manuel; Paradelo Núñez, Remigio; Fernández Calviño, David; Nóvoa Muñoz, Juan Carlos; Arias Estévez, Manuel

    2017-04-01

    Competitive adsorption and desorption of three quaternary ammonium herbicides (paraquat, diquat, and difenzoquat) have been studied in four sandy-loam acid vineyard soils from NW Spain and Portugal. The soils present organic matter contents between 3 and 48 g kg-1 and copper contents ranging from 25 to 107 mg kg-1. Adsorption has been studied under equilibrium conditions in batch experiments, and kinetics were studied in a stirred-flow chamber. Adsorption and desorption followed a Freundlich model and kinetics were well described by the pseudo-first-order model. The retention capacity for the pesticides by the four soils followed the sequence: paraquat > diquat > difenzoquat. The different adsorption capacities of each soil were not related to pH, clay or organic matter contents, as could be expected, but rather to soil copper content. The results show that competition with copper for adsorption sites is an important factor in quaternary ammonium herbicides retention in soils with these characteristics.

  5. Kinematics of the quaternary fault zones in the Kyeongju area of the southeastern Korean Peninsula

    International Nuclear Information System (INIS)

    Kim, In Seob; Lee, Byeong Hyui; Kwon, Hyeok Sang

    1998-09-01

    The purposes of this study are to interpret the kinematics of the Quaternary fault zones in the Kyeongju area, to determine deformation mechanisms during faulting by analyzing micorstrucutres of fault rocks from the fault zones, and to unravel the technic evaluation of the regional fault structures in the Kyeongju-Wolsung area. The scope of this study consists of ; collection and interpretation of structural elements through a detailed geologic investigation on the Quaternary faults in the Kyeongju-Wolsung area, interpretation of fault-rock microstructures from the fault zones using oriented samples of faults rocks, determination of deformation processes and mechanisms of the fault rocks and, interpretation of faulting kinematics and evaluation of the fault zones

  6. Paleomagnetic dating of tectonically influenced Plio-Quaternary fan-system deposits from the Apennines (Italy

    Directory of Open Access Journals (Sweden)

    Michele Saroli

    2015-03-01

    Full Text Available The Roveto Valley is a narrow, elongated, NW-trending depression filled with continental Plio-Quaternary deposits that outcrop at different topographic elevations. A morpho-lithostratigraphic succession of the continental deposits has been defined in order to reconstruct the geological Quaternary evolution of the area. These deposits do not contain materials suitable for biostratigraphic dating; therefore, in order to determine their chronology, three different units were sampled for magnetostratigraphic investigations. Paleomagnetic results demonstrated that standard demagnetization techniques are effective in removing secondary remanence components and in isolating the characteristic remanent magnetization, allowing us to determine, for each cycle, whether it was deposited before or after the Brunhes-Matuyama geomagnetic reversal at 781 ka. Preliminary rock magnetic analyses indicated that magnetite is the main magnetic carrier and that hematite, which gives the pink colour to the matrix, is in the superparamagnetic grain-size range and thus does not retain any paleomagnetic remanence.

  7. Risk-to-Benefit Ratio of Venous Thromboembolism Prophylaxis for Neurosurgical Procedures at a Quaternary Referral Center.

    Science.gov (United States)

    Agarwal, Nitin; Zenonos, Georgios A; Agarwal, Prateek; Walch, Frank J; Roach, Eileen; Stokes, Sandra J; Friedlander, Robert M; Gerszten, Peter C

    2018-03-09

    Pharmacological prophylaxis for venous thromboembolism (VTE) in the neurosurgical population is still a matter of debate, as the risk-to-benefit ratio is not well defined. To further evaluate the risk-to-benefit ratio of VTE prophylaxis (VTEP) for all neurosurgical procedures. A prospective evaluation was performed after the initiation of a VTEP protocol for 11 436 patients undergoing neurosurgical procedures over 24 mo. Unless a bleeding complication was present, 5000 international units of subcutaneous heparin every 8 h was ordered on postoperative day (POD) 1 for spine, POD2 for cranial, and by POD4 for subdural, intracerebral, and epidural hematoma cases. Incidence of VTE and any subsequent bleeding complications were noted. A total of 70 VTEs (0.6% overall) were documented (28 deep vein thrombosis, 42 pulmonary embnolism). The highest rates of VTE were associated with deformity (6.7%); open cerebrovascular (6.5%); subdural, intracerebral, and epidural hematoma (3.2%); spinal trauma (2.4%); and craniotomy for tumor (1.6%) cases. Seven cases of deep vein thrombosis progressed to pulmonary embolisms, and 66 of 70 VTEs occurred while on pharmacological VTEP. Fifty-four bleeding complications occurred on or after POD2 following initiation of VTEP. These bleeding complications consisted of any new clinically or radiographically observed hemorrhages. Twenty-eight of the 54 delayed bleeding complications required operative intervention with 1 mortality. Forty-five patients were on anticoagulation when the initial bleeding event occurred. Overall, an estimated 0.5% incidence of delayed bleeding complications was noted with 99.4% of patients within the study cohort remaining VTE free. This VTEP protocol was determined to afford a good risk-to-benefit ratio for a wide variety of neurosurgical procedures.

  8. Mathematical and computational aspects of quaternary liquid mixing free energy measurement using light scattering.

    Science.gov (United States)

    Wahle, Chris W; Ross, David S; Thurston, George M

    2012-07-21

    We provide a mathematical and computational analysis of light scattering measurement of mixing free energies of quaternary isotropic liquids. In previous work, we analyzed mathematical and experimental design considerations for the ternary mixture case [D. Ross, G. Thurston, and C. Lutzer, J. Chem. Phys. 129, 064106 (2008); C. Wahle, D. Ross, and G. Thurston, J. Chem. Phys. 137, 034201 (2012)]. Here, we review and introduce dimension-free general formulations of the fully nonlinear partial differential equation (PDE) and its linearization, a basis for applying the method to composition spaces of any dimension, in principle. With numerical analysis of the PDE as applied to the light scattering implied by a test free energy and dielectric gradient combination, we show that values of the Rayleigh ratio within the quaternary composition tetrahedron can be used to correctly reconstruct the composition dependence of the free energy. We then extend the analysis to the case of a finite number of data points, measured with noise. In this context the linearized PDE describes the relevant diffusion of information from light scattering noise to the free energy. The fully nonlinear PDE creates a special set of curves in the composition tetrahedron, collections of which form characteristics of the nonlinear and linear PDEs, and we show that the information diffusion has a time-like direction along the positive normals to these curves. With use of Monte Carlo simulations of light scattering experiments, we find that for a modest laboratory light scattering setup, about 100-200 samples and 100 s of measurement time are enough to be able to measure the mixing free energy over the entire quaternary composition tetrahedron, to within an L(2) error norm of 10(-3). The present method can help quantify thermodynamics of quaternary isotropic liquid mixtures.

  9. Interactions between Intracellular Domains as Key Determinants of the Quaternary Structure and Function of Receptor Heteromers*

    Science.gov (United States)

    Navarro, Gemma; Ferré, Sergi; Cordomi, Arnau; Moreno, Estefania; Mallol, Josefa; Casadó, Vicent; Cortés, Antoni; Hoffmann, Hanne; Ortiz, Jordi; Canela, Enric I.; Lluís, Carme; Pardo, Leonardo; Franco, Rafael; Woods, Amina S.

    2010-01-01

    G protein-coupled receptor (GPCR) heteromers are macromolecular complexes with unique functional properties different from those of its individual protomers. Little is known about what determines the quaternary structure of GPCR heteromers resulting in their unique functional properties. In this study, using resonance energy transfer techniques in experiments with mutated receptors, we provide for the first time clear evidence for a key role of intracellular domains in the determination of the quaternary structure of GPCR heteromers between adenosine A2A, cannabinoid CB1, and dopamine D2 receptors. In these interactions, arginine-rich epitopes form salt bridges with phosphorylated serine or threonine residues from CK1/2 consensus sites. Each receptor (A2A, CB1, and D2) was found to include two evolutionarily conserved intracellular domains to establish selective electrostatic interactions with intracellular domains of the other two receptors, indicating that these particular electrostatic interactions constitute a general mechanism for receptor heteromerization. Mutation experiments indicated that the interactions of the intracellular domains of the CB1 receptor with A2A and D2 receptors are fundamental for the correct formation of the quaternary structure needed for the function (MAPK signaling) of the A2A-CB1-D2 receptor heteromers. Analysis of MAPK signaling in striatal slices of CB1 receptor KO mice and wild-type littermates supported the existence of A1-CB1-D2 receptor heteromer in the brain. These findings allowed us to propose the first molecular model of the quaternary structure of a receptor heteromultimer. PMID:20562103

  10. AM1 CI and ZINDO/S study of quaternary salts of diazaphenanthrenes with haloalkanes

    Science.gov (United States)

    Peszke, Jerzy; Śliwa, Wanda

    2002-08-01

    For quaternary salts of diazaphenanthrenes 1- 3 with methyl iodide 4- 6, diiodomethane 7- 9 and 1,2-dibromoethane 10- 12 UV spectral values have been calculated by AM1 CI, and in the case of 4- 6 also with ZINDO/S method. Correlations of experimental and calculated wavenumber values of considered compounds show good compatibility. For geometry optimisation of 4- 9 the AM1 CI method has been used.

  11. Synthesis of CID-cleavable protein crosslinking agents containing quaternary amines for structural mass spectrometry.

    Science.gov (United States)

    Hagen, Susan E; Liu, Kun; Jin, Yafei; Piersimoni, Lolita; Andrews, Philip C; Showalter, Hollis D

    2018-03-14

    Two novel cyclic quaternary amine crosslinking probes are synthesized for structural mass spectrometry of protein complexes in solution and for analysis of protein interactions in organellar and whole cell extracts. Each exhibits high aqueous solubility, excellent protein crosslinking efficiencies, low collision induced dissociation (CID) energy fragmentation efficiencies, high stoichiometries of reaction, increased charges of crosslinked peptide ions, and maintenance of overall surface charge balance of crosslinked proteins.

  12. Chemistry of solvent extraction of rare metals by quaternary ammonium salts

    International Nuclear Information System (INIS)

    Stepanov, S.I.

    1996-01-01

    An investigation of the liquid-liquid extraction of Ti, Nb,Ta, Cr(VI), Mo(VI), W(VI), U(VI), Th(lV), Sc, Y and lanthanoids, as well as mineral acids and alkaline metals, using quaternary ammonium salts, alone, and with mixtures of other classes of extractants is reported. The composition of extracted compounds and the mechanism of their extraction are discussed

  13. Evaluation of the transfection efficacies of quaternary ammonium salts prepared from sophorolipids

    OpenAIRE

    Delbeke, E,; Lozach, Olivier; Le Gall, T; Berchel, Mathieu,; Montier, T,; Jaffres, Paul-Alain; Van Geem, K,; Stevens, C,

    2016-01-01

    International audience; Five quaternary ammonium amphiphilic compounds were synthesized from sophorolipid 1. These compounds were formulated in aqueous media and some of them (5 and 6) produced well-defined supra-molecular aggregates which were characterized by DLS and zeta measurements. Their capacity to transfect four different eukaryotic cell lines in vitro was assessed. To evaluate the influence of the carbohydrate head group from the sophorolipids on the transfection efficacies, their de...

  14. Global late Quaternary megafauna extinctions linked to humans, not climate change

    OpenAIRE

    Sandom, C.; Faurby, S.; Sandel, B.; Svenning, J.-C.

    2014-01-01

    The late Quaternary megafauna extinction was a severe global-scale event. Two factors, climate change and modern humans, have received broad support as the primary drivers, but their absolute and relative importance remains controversial. To date, focus has been on the extinction chronology of individual or small groups of species, specific geographical regions or macroscale studies at very coarse geographical and taxonomic resolution, limiting the possibility of adequately testing the propos...

  15. Crystal structure of the quaternary compounds CuFe2AlSe4 and ...

    Indian Academy of Sciences (India)

    3Laboratorio de Análisis Químico y Estructural, Departamento de Física, Facultad de Ciencias,. Universidad de Los Andes, Mérida 5101, Venezuela. MS received 29 May 2014; accepted 3 February 2015. Abstract. The crystal structure of the quaternary compounds CuFe2AlSe4 and CuFe2GaSe4, belonging to the.

  16. Quantitative analysis of deuterium using the isotopic effect on quaternary {sup 13}C NMR chemical shifts

    Energy Technology Data Exchange (ETDEWEB)

    Darwish, Tamim A., E-mail: tamim.darwish@ansto.gov.au [National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Locked Bag 21, Kirrawee DC, NSW 2232 (Australia); Yepuri, Nageshwar Rao; Holden, Peter J. [National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Locked Bag 21, Kirrawee DC, NSW 2232 (Australia); James, Michael [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia)

    2016-07-13

    Quantitative analysis of specifically deuterated compounds can be achieved by a number of conventional methods, such as mass spectroscopy, or by quantifying the residual {sup 1}H NMR signals compared to signals from internal standards. However, site specific quantification using these methods becomes challenging when dealing with non-specifically or randomly deuterated compounds that are produced by metal catalyzed hydrothermal reactions in D{sub 2}O, one of the most convenient deuteration methods. In this study, deuterium-induced NMR isotope shifts of quaternary {sup 13}C resonances neighboring deuterated sites have been utilized to quantify the degree of isotope labeling of molecular sites in non-specifically deuterated molecules. By probing {sup 13}C NMR signals while decoupling both proton and deuterium nuclei, it is possible to resolve {sup 13}C resonances of the different isotopologues based on the isotopic shifts and the degree of deuteration of the carbon atoms. We demonstrate that in different isotopologues, the same quaternary carbon, neighboring partially deuterated carbon atoms, are affected to an equal extent by relaxation. Decoupling both nuclei ({sup 1}H, {sup 2}H) resolves closely separated quaternary {sup 13}C signals of the different isotopologues, and allows their accurate integration and quantification under short relaxation delays (D1 = 1 s) and hence fast accumulative spectral acquisition. We have performed a number of approaches to quantify the deuterium content at different specific sites to demonstrate a convenient and generic analysis method for use in randomly deuterated molecules, or in cases of specifically deuterated molecules where back-exchange processes may take place during work up. - Graphical abstract: The relative intensities of quaternary {sup 13}C {"1H,"2H} resonances are equal despite the different relaxation delays, allowing the relative abundance of the different deuterated isotopologues to be calculated using NMR fast

  17. Thrust geometries in unconsolidated Quaternary sediments around the Eupchon fault, SE Korea

    Science.gov (United States)

    Park, J. Y.; Kim, Y.-S.; Kim, J. H.; Shin, H. C.

    2003-04-01

    It had been considered that Korean Peninsula is located in a relatively stable continental platform. Over ten Quaternary faults have recently been discovered, however, in the south-eastern part of the Korean Peninsula. The Eupchon Fault was discovered at the construction site of a primary school, close to a nuclear power plant. In order to understand the characteristics of the Eupchon fault, we carried out two trench surveys near the first finding site. The orientations of trench sites are 150o and 170o, the widths are 1.3 m and 1.5 m, and the maximum depths are 2.8 m and 5.5 m, respectively. The trenches are in Quaternary unconsolidated marine terrace sediments, which have horizontal bedding planes, are well sorted, and range from pebbles to muds The fault system includes one main reverse fault (N20o E/40o SE) with about 4m displacement and a series of branches. Structures in the fault system include synthetic and antithetic faults, hanging wall anticlines, drag folds, back thrusts, pop-up structures, flat-ramp geometries and duplexes, i.e. very similar to thrust systems in consolidated rocks. In the upper part of the fault system, several tip damage zone patterns are observed, indicating that the fault system terminates in the upper part of the section. Pebbles along the main fault plane show preferred orientation of long axes indicating the fault trace. The orientation of the slickenside striea is E-W, indicating the movement direction. The unconformity between the Quaternary deposits and the underlying Tertiary andesites and Cretaceous sedimentary rocks is displaced in a reverse sense. A normal displacement was reported lower in the section, indicating the fault had a normal displacement and was reverse reactivated during the Quaternary.

  18. A multi-disciplinary review of late Quaternary palaeoclimates and environments for Lesotho

    Directory of Open Access Journals (Sweden)

    Jennifer M. Fitchett

    2016-07-01

    Full Text Available Lesotho provides a unique context for palaeoclimatic research. The small country is entirely landlocked by South Africa, yet has considerable variation in topography, climate, and associated vegetation over an approximate east-west transect. The region has been of archaeological interest for over a century, and hosts many Early to Late Stone Age sites with occupation preceding 80 000 years before present. The eastern Lesotho highlands are of interest to periglacial and glacial geomorphologists because of their well-preserved relict landforms and contentious evidence for permafrost and niche glaciation during the late Quaternary. However, continuous proxy records for palaeoenvironmental reconstructions for Lesotho are scarce and hampered by a range of methodological shortfalls. These challenges include uncertain ages, poor sampling resolution, and proxies extracted from archaeological excavations for which there may be bias in selection. Inferences on palaeoclimates are thus based predominantly on archaeological and palaeogeomorphological evidence for discrete periods during the late Quaternary. This review paper presents a more detailed multidisciplinary synthesis of late Quaternary conditions in Lesotho. We simultaneously considered the varying data that contribute to the under-studied palaeoenvironmental record for southern Africa. The collective palaeoenvironmental data for eastern Lesotho were shown to be relatively contradictory, with considerable variations in contemporaneous palaeoclimatic conditions within the study area. We argue that although methodological challenges may contribute to this variation, the marked changes in topography result in contrasting late Quaternary palaeoenvironments. Such environments are characterised by similar contrasting microclimates and niche ecologies as are witnessed in the contemporary landscape. These spatial variations within a relatively small landlocked country are of importance in understanding

  19. Characterization and bioactivity of novel calcium antagonists - N-methoxy-benzyl haloperidol quaternary ammonium salt

    OpenAIRE

    Chen, Yi-Cun; Zhu, Wei; Zhong, Shu-Ping; Zheng, Fu-Chun; Gao, Fen-Fei; Zhang, Yan-Mei; Xu, Han; Zheng, Yan-Shan; Shi, Gang-Gang

    2015-01-01

    BACKGROUND AND PURPOSE Calcium antagonists play an important role in clinical practice. However, most of them have serious side effects. We have synthesized a series of novel calcium antagonists, quaternary ammonium salt derivatives of haloperidol with N-p-methoxybenzyl (X1), N-m-methoxybenzyl (X2) and N-o-methoxybenzyl (X3) groups. The objective of this study was to investigate the bioactivity of these novel calcium antagonists, especially the vasodilation activity and cardiac side-effects. ...

  20. Effect of quaternary ammonium salts in the process of extracting oil filled rubber from latex

    Directory of Open Access Journals (Sweden)

    N. S. Nikulina

    2016-01-01

    Full Text Available Currently, much attention is paid to the improvement of production technology of synthetic rubber. Much attention is given to rubber is produced by emulsion polymerization. This is due to the fact that rubbers produced by emulsion polymerization have a number of positive characteristics, and are widely used in the tire and rubber industry, in composite formulations for various purposes. In recent years, the technology of production of synthetic rubbers are widely used quaternary ammonium salts which are produced on an industrial scale. Application low and high molecular weight quaternary ammonium salts to reduce pollution of environ-mental protection, exclude the use of mineral salts without significant changes in the process flowsheet. It is found that quaternary ammonium salts react with the components of the emulsion system to form insoluble complexes, which are captured produced rubber crumb. However, Applications, quaternary salts in the manufacture of oil-filled rubber in the literature sources have not been given due attention. The study presents the results of research on the effect of the concentration of a coagulating agent, tempera tours and concentration of the dispersed phase in the process of coagulation of latex in the preparation of oil-filled rubber stamps SCS-30 ARKM-15. The concentration of the coagulating agent does not significantly affect the process of separation of the rubber from the latex. The process of isolation rubber latex is advantageously carried out at a reduced temperature. The concentration of the dispersed phase also provides material effect on the coagulation process. The lead researches mouthestablished that produced rubber, rubber compounds and vulcanizates based on these indicators correspond to their requirements.

  1. Plio-quaternary deposits in the Eastern Rharb (Nw Morocco): Electrosequential characterization

    Science.gov (United States)

    Al Mazini, Imane; Mridekh, Abdelaziz; Kili, Malika; El Mansouri, Bouâbid; El Bouhaddioui, Mohamed; Magrane, Bouchaib

    2018-02-01

    The Rharb basin, of which our study area is part, is located at the western extremity of the south Rif corridor. It corresponds to a subsiding zone that appeared in the Upper Miocene, between two major structural domains: the Rif to the north and east and the Meseta domain to the south. The eastern part of this basin is characterized by a Plio-Quaternary continental fill. Its geographical position and its structural and paleo-environmental contexts are reflected by a great facies heterogeneity. This work aims to image the subsurface structure and to characterize the distribution mode of Plio-Quaternary deposits of the eastern Rharb. The use of a database consisting of geo-electrical cross sections, hydrogeological drilling and wireline logging integrated in a Geographic Information System (GIS) allowed us to establish a new three-dimensional model of the top of the Mio-Pliocene substratum, new geo-electrical cross sections, as well as the isopach maps of lower, intermediate, upper and superficial geo-electric interval. This approach allowed us to characterize the Plio-Quaternary deposits of the study area and to highlight the effects of the tectonic regime and the relative sea level fluctuations on the sequential organization of these deposits. Our new model shows the development of prograding, aggrading and retrograding parasequences denoting the existence of autogenic mechanisms in the organization of plio-quaternary deposits of the eastern part of the Rharb basin. Therefore, it opens new perspectives for the exploration of water resources and monitoring their quality throughout the basin.

  2. Synthesis and Characterization of Novel Ternary and Quaternary Alkali Metal Thiophosphates

    KAUST Repository

    Alahmary, Fatimah S.

    2014-05-01

    The ongoing development of nonlinear optical (NLO) crystals such as coherent mid-IR sources focuses on various classes of materials such as ternary and quaternary metal chalcophosphates. In case of thiophosphates, the connection between PS4-tetrahedral building blocks and metals gives rise to a broad structural variety where approximately one third of all known ternary (A/P/S) and quaternary (A/M/P/S) (A = alkali metal, M = metal) structures are acentric and potential nonlinear optical materials. The molten alkali metal polychalcophosphate fluxes are a well-established method for the synthesis of new ternary and quaternary thiophosphate and selenophosphate compounds. It has been a wide field of study and investigation through the last two decades. Here, the flux method is used for the synthesis of new quaternary phases containing Rb, Ag, P and S. Four new alkali metal thiophosphates, Rb4P2S10, RbAg5(PS4), Rb2AgPS4 and Rb3Ag9(PS4)4, have been synthesized successfully from high purity elements and binary starting materials. The new compounds were characterized by single crystal and powder X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), ultraviolet-visible (UV-VIS), Raman spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). These compounds show interesting structural variety and physical properties. The crystal structures feature 3D anionic framework built up of PS4 tetrahedral units and charge balanced by Ag and alkali metal cations. All prepared compounds are semiconductors with band gap between 2.3 eV to 2.6 eV and most of them are thermally stable up to 600ºC.

  3. Evaluation of Sintering Behaviors of Saprolitic Nickeliferous Laterite Based on Quaternary Basicity

    Science.gov (United States)

    Luo, Jun; Li, Guanghui; Rao, Mingjun; Zhang, Yuanbo; Peng, Zhiwei; Zhi, Qian; Jiang, Tao

    2015-09-01

    The sintering behaviors of saprolitic nickeliferous laterite with various quaternary basicities [(CaO + MgO)/(SiO2 + Al2O3) mass ratio] in a reductive atmosphere are investigated by simulative sintering and validated by sintering pot tests. The simulative sintering results show that the generation of diopside (CaMgSi2O6) with low melting point is the key reason for the decrease in characteristic fusion temperatures when the quaternary basicity increases from 0.5 to 0.8-1.0. Continuous increase of basicity leads to transformation of diopside (CaMgSi2O6) into akermanite (Ca2MgSi2O7), which adversely increases the characteristic fusion temperatures. These findings are confirmed by the sinter pot tests, which demonstrate that the sintering indexes including vertical sintering velocity (VSV), yield ( Y), and productivity ( P), can be improved by optimizing quaternary basicity. At basicity of 1.0, the VSV, Y, P, and ISO tumbling index reach 49.2 mm/min, 80.5%, 1.0 t/(h m2), and 66.5%, respectively.

  4. Slump structures in quaternary slope sediments of the northern Derbent Basin (Caspian Sea)

    Science.gov (United States)

    Verzhbitskii, V. E.; Lobkovskii, L. I.; Roslyakov, A. G.; Merklin, L. R.; Polyakov, A. S.; Levchenko, O. V.; Kovachev, S. A.; Zverev, A. S.; Garagash, I. A.; Mar, G. N.; Mutovkin, A. D.; Putans, V. A.; Libina, N. V.; Soltanovskii, I. I.; Slobodyan, V. Yu.; Gontarev, S. V.

    2009-06-01

    During Cruise 20-3 of the R/V Rift (April, 2006), the area that includes the shelf and slope of the Derbent Basin in the northern Middle Caspian was studied using the continuous seismoacoustic profiling method. In accordance with the previous standpoint, two Pleistocene deltaic complexes formed in the Enotaevian and Mangyshlakian time are defined in this area. The seismoacoustic records obtained for the northern slope of the Derbent Basin demonstrate the development of specific rootless exogenic-gravitational fold structures in the upper (˜150-200 m) Quaternary part of the sedimentary sequence. The Quaternary section encloses angular unconformities indicating the pulsating mode of gravitational processes in the northern slope of the basin. South-dipping gravitational normal faults (and/or normal fault-related flexures) displacing the bottom surface and uppermost sedimentary layers (with vertical amplitudes up to 5-6 m) were defined in the southern part of the study area. Several impulses of the submarine slump structures predated and accompanied the deposition of the upper deltaic sequence (Mangyshlakian), although their most intense formation took place later during the Novocaspian (Holocene) time. Thus, the structural analysis of the seismoacoustic data revealed intense development of different-origin and different-age gravitational structures within the Quaternary sediments in the northern slope of the Derbent Basin. These results should be taken into consideration when designing, building, and operating submarine constructions in order to prevent potential natural hazards and reduce their consequences.

  5. Monsoon triggered formation of Quaternary alluvial megafans in the interior of Oman

    Science.gov (United States)

    Blechschmidt, Ingo; Matter, Albert; Preusser, Frank; Rieke-Zapp, Dirk

    2009-09-01

    A vast bajada consisting of coalescing low-gradient (age termed Barzaman Formation, diagenetically highly altered to dolomitic clays, and a thin veneer of weakly cemented Quaternary gravels. A combination of remote sensing, lithological analyses and luminescence dating is used to interpret the complex aggradation history of the Quaternary alluvial fans from the interior of Oman in the context of independent regional climate records. From satellite imagery and clast analysis four fans can be discerned in the study area. While two early periods of fan formation are tentatively correlated to the Miocene-Pliocene and the Early Pleistocene, luminescence dating allows the distinction of five phases of fan aggradation during the Middle-Late Pleistocene. These phases are correlated with pluvial periods from Marine Isotope Stage (MIS) 11 through 3, when southern Arabia was affected by monsoonal precipitation. It is concluded that the aggradation of the alluvial fans was triggered by the interplay of increased sediment production during arid periods and high rainfall with enhanced erosion of hillslopes and transport rates during strong monsoon phases. However, the lack of fine-grained sediments, bioturbation and organic material implies that although the Quaternary fans are sourced by monsoonal rains they formed in a semi-arid environment. Thus, it appears that, in contrast to the Oman Mountains, the interior was not directly affected by monsoonal precipitation.

  6. Quaternary fluvial response to climate change in glacially influenced river systems

    Science.gov (United States)

    Cordier, Stéphane; Adamson, Kathryn; Delmas, Magali; Calvet, Marc; Harmand, Dominique

    2016-04-01

    Over the last few decades, many studies in Europe and other continents have focused on the fluvial response to climate forcing in unglaciated basins. However, glacial activity may have a profound impact on the behaviour of the fluvial systems located downstream. In comparison to ice-free basins, these systems are characterised by distinctive hydrological and sediment supply regimes. Over Quaternary timescales, the fluvial records are influenced by periglacial (in non-glaciated areas), proglacial, and paraglacial processes. Understanding the impacts of these processes on the formation and preservation of the Quaternary geomorphological and sedimentary archives is key for our understanding of glacial-fluvial interactions. We investigate the impact of Quaternary glacial activity on fluvial sediment transfer, deposition, and preservation. Using existing studies from across Europe, we create a database of glaciofluvial geomorphology, sedimentology, and geochronology. This is used to examine how glacial forcing of fluvial systems varies spatially in different basin settings, and temporally over successive Milankovitch cycles. In particular, we focus on the ways in which the primary glacial-fluvial depositional signal could be distinguished from periglacial and paraglacial reworking and redeposition.

  7. Phase study in Sr-Th-P-O system: Structural and thermal investigations of quaternary compounds

    International Nuclear Information System (INIS)

    Keskar, Meera; Phatak, Rohan; Sali, S.K.; Krishnan, K.; Dahale, N.D.; Kulkarni, N.K.; Kannan, S.

    2011-01-01

    The sub-solidus phase relations in Sr-Th-P-O quaternary system were determined at 1223 K in air. To confirm the formation and stability of reported phases, ternary and quaternary compounds in Sr-Th-O, Sr-P-O, Th-P-O and Sr-Th-P-O systems were synthesized by solid state reactions of SrCO 3 , ThO 2 and NH 4 H 2 PO 4 in desired molar proportions at 1223 K. A pseudo-ternary phase diagram of SrO-ThO 2 -P 2 O 5 system was drawn on the basis of the phase analysis of various phase mixtures and phase fields were established by powder X-ray diffraction. In the phase diagram, three quaternary compounds SrTh(PO 4 ) 2 , SrTh 4 (PO 4 ) 6 and Sr 7 Th(PO 4 ) 6 were identified. When heated in air at 1673 K, these compounds decompose to ThO 2 . Structures of SrTh(PO 4 ) 2 , SrTh 4 (PO 4 ) 6 and Sr 7 Th(PO 4 ) 6 were derived from X-ray powder data using the Rietveld refinement method. Thermal expansion behaviors of SrTh(PO 4 ) 2 , SrTh 4 (PO 4 ) 6 and Sr 7 Th(PO 4 ) 6 were investigated using high-temperature X-ray diffraction in the temperature range of 298-1273 K.

  8. Hydrolysis of cellulose catalyzed by quaternary ammonium perrhenates in 1-allyl-3-methylimidazolium chloride.

    Science.gov (United States)

    Wang, Jingyun; Zhou, Mingdong; Yuan, Yuguo; Zhang, Quan; Fang, Xiangchen; Zang, Shuliang

    2015-12-01

    Quaternary ammonium perrhenates were applied as catalyst to promote the hydrolysis of cellulose in 1-allyl-3-methylimidazolium chloride ([Amim]Cl). The quaternary ammonium perrhenates displayed good catalytic performance for cellulose hydrolysis. Water was also proven to be effective to promote cellulose hydrolysis. Accordingly, 97% of total reduced sugar (TRS) and 42% of glucose yields could be obtained under the condition of using 5mol% of tetramethyl ammonium perrhenate as catalyst, 70μL of water, ca. 0.6mmol of microcrystalline cellulose (MCC) and 2.0g of [Amim]Cl as solvent under microwave irradiation for 30min at 150°C (optimal conditions). The influence of quaternary ammonium cation on the efficiency of cellulose hydrolysis was examined based on different cation structures of perrhenates. The mechanism on perrhenate catalyzed cellulose hydrolysis is also discussed, whereas hydrogen bonding between ReO4 anion and hydroxyl groups of cellulose is assumed to be the key step for depolymerization of cellulose. Copyright © 2015. Published by Elsevier Ltd.

  9. Mechanical properties of some binary, ternary and quaternary III-V compound semiconductor alloys

    International Nuclear Information System (INIS)

    Navamathavan, R.; Arivuoli, D.; Attolini, G.; Pelosi, C.; Choi, Chi Kyu

    2007-01-01

    Vicker's microindentation tests have been carried out on InP/InP, GaAs/InP, InGaAs/InP and InGaAsP/InP III-V compound semiconductor alloys. The detailed mechanical properties of these binary, ternary and quaternary epilayers were determined from the indentation experiments. Microindentation studies of (1 1 1) GaAs/InP both A and B faces show that the hardness value increases with load and attains a constant for further increase in load and the microhardness values were found to lie between 3.5 and 4.0 GPa. The microhardness values of InGaAs/InP epilayers with different thickness were found to lie between 3.93 and 4.312 GPa. The microhardness values of InGaAsP/InP with different elemental composition were found to lie between 5.08 and 5.73 GPa. The results show that the hardness of the quaternary alloy drastically increases, the reason may be that the increase in As concentration hardens the lattice when phosphorous concentration is less and hardness decreases when phosphorous is increased. It was interestingly observed that the hardness value increases as we proceed from binary to quaternary III-V compound semiconductor alloys

  10. Phase identification and structure investigation of novel quaternary rare-earth substituted titanates

    Science.gov (United States)

    Aldridge, James D.; Womick, Jordan M.; Rosmus, Kimberly A.; Weiland, Ashley; Aitken, Jennifer A.; Polvani, Deborah A.

    2017-12-01

    Novel quaternary lanthanide-substituted oxides of stoichiometry LnxY2-xTi2O7 (where Ln is lanthanum, neodymium, samarium, gadolinium, or ytterbium) were prepared by traditional high-temperature, solid-state techniques and characterized by X-ray powder diffraction. Samples with nominal values of x up to 1.0 were attempted. The well-studied ternary cubic pyrochlore compound yttrium titanium oxide (Y2Ti2O7, space group Fd-3m, Z = 8), served as a parent structural framework in which Ln3+ cations were substituted on the Y3+ site. Laboratory-grade X-ray powder diffraction data revealed pure quaternary pyrochlore phases for LnxY2-xTi2O7 with x ≤ 0.2. Pyrochlore phase purity was verified by Rietveld analysis using high-resolution synchrotron X-ray powder diffraction data when x ≤ 0.2, however, for La3+ substitution specifically, pure quaternary pyrochlore formed at x<0.1. Band gap energies on selected samples were determined using optical diffuse reflectance spectroscopy and showed that these materials can be classified as electrical insulators with indirect band gap energies around 3.7 eV.

  11. Polarization encoded all-optical quaternary R-S flip-flop using binary latch

    Science.gov (United States)

    Chattopadhyay, Tanay; Roy, Jitendra Nath; Chakraborty, Ajoy Kumar

    2009-04-01

    The developments of different multi-valued logic (MVL) systems have received considerable interests in recent years all over the world. In electronics, efforts have already been made to incorporate multi-valued system in logic and arithmetic data processing. But, very little efforts have been given in realization of MVL with optics. In this paper we present novel designs of certain all-optical circuits that can be used for realizing multi-valued logic functions. Polarization encoded all-optical quaternary (4-valued) R-S flip-flop is proposed and described. Two key circuits (all-optical encoder/decoder and a binary latch) are designed first. They are used to realize quaternary flip-flop in all-optical domain. Here the different quaternary logical states are represented by different polarized state of light. Terahertz Optical Asymmetric Demultiplexer (TOAD) based interferometric switch can take an important role. Computer simulation result confirming described methods and conclusion are given in this paper.

  12. Physical, chemical and antimicrobial evaluation of a composite material containing quaternary ammonium salt for braces cementation

    International Nuclear Information System (INIS)

    Sugii, Mari Miura; Ferreira, Fábio Augusto de Souza; Müller, Karina Cogo; Lima, Debora Alves Nunes Leite; Groppo, Francisco Carlos; Imasato, Hidetake; Rodrigues-Filho, Ubirajara Pereira

    2017-01-01

    The antibiofilm effect of iodide quaternary ammonium methacryloxy silicate (IQAMS) in Transbond XT Light Cure Adhesive resin used for braces cementation was evaluated. Fourier Transform Infrared (FTIR) spectroscopy confirmed IQAMS formation and Scanning Electron Microscopy coupled to Energy-Dispersive X-ray Spectroscopy (SEM-EDS) revealed that as coating, the quaternary ammonium groups from IQAMS were homogeneously dispersed throughout the surface. When incorporated, the composite material presented homogeneous dispersion throughout the resin. Assays with Streptococcus mutans demonstrated enhanced antibiofilm effect for the IQAMS coated resin, with much lower colony-forming units (CFU), in comparison to incorporated IQAMS. Such a difference was assigned to low availability of quaternary ammonium groups at the surface of resin when IQAMS was incorporated, hindering its antibiofilm effect. Additionally, the incorporation of IQAMS led to slight decrease in ultimate bond strength (UBS) and shear bond strength (SBS), in comparison to the neat commercial resin. Thus, the synthesized IQAMS displays great potential as antibiofilm coating or sealant to prevent oral infections in brackets during orthodontic treatment. - Highlights: • Synthesis of ORMOSIL-based material with antibiofilm activity is performed. • Antibiofilm activity of the ORMOSIL-based material on commercial available resin for braces cementation is evaluated. • Antibiofilm ORMOSIL-based coating with potential application as varnish or sealant in orthodontic appliances is presented.

  13. Structural effect of quaternary ammonium chitin derivatives on their bactericidal activity and specificity.

    Science.gov (United States)

    Morkaew, Tirut; Pinyakong, Onruthai; Tachaboonyakiat, Wanpen

    2017-08-01

    The effect of the quaternary ammonium chitin structure on the bactericidal activity and specificity against Escherichia coli and Staphylococcus aureus was investigated. Quaternary ammonium chitins were synthesized by the separate acylation of chitin (CT) with carboxymethyl trimethylammonium chloride (CMA), 3-carboxypropyl trimethylammonium chloride (CPA) and N-dodecyl-N,N-(dimethylammonio)butyrate (DDMAB). The successful acylation was confirmed by newly formed ester linkage. All three derivatives had a higher surface charge than chitin due to the additional positively charged quaternary ammonium groups. The N-short alkyl substituent (methyl) of CTCMA and CTCPA increased the hydrophilicity whilst the N-long alkyl substituent (dodecyl) of CTDDMAB increased the hydrophobicity compared to chitin. Chitin did not exhibit any bactericidal activity, while CTCMA and CTCPA completely killed E. coli and S. aureus in 30 and 60min, respectively, and CTDDMAB completely killed S. aureus in 10min but did not kill E. coli after a 2-h exposure. Therefore, the N-short alkyl substituent was more effective for killing E. coli and the N-long alkyl substituent conferred specific bactericidal activity against S. aureus. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Design, synthesis of novel chitosan derivatives bearing quaternary phosphonium salts and evaluation of antifungal activity.

    Science.gov (United States)

    Tan, Wenqiang; Zhang, Jingjing; Luan, Fang; Wei, Lijie; Chen, Yuan; Dong, Fang; Li, Qing; Guo, Zhanyong

    2017-09-01

    Two novel chitosan derivatives modified with quaternary phosphonium salts were successfully synthesized, including tricyclohexylphosphonium acetyl chitosan chloride (TCPACSC) and triphenylphosphonium acetyl chitosan chloride (TPPACSC), and characterized by FTIR, 1 H NMR, and 13 C NMR spectra. The degree of substitution was also calculated by elemental analysis results. Their antifungal activities against Colletotrichum lagenarium, Watermelon fusarium, and Fusarium oxysporum were investigated in vitro using the radial growth assay, minimal inhibitory concentration, and minimum bactericidal concentration assay. The fungicidal assessment revealed that the synthesized chitosan derivatives had superior antifungal activity compared with chitosan. Especially, TPPACSC exhibited the best antifungal property with inhibitory indices of over 75% at 1.0mg/mL. The results obviously showed that quaternary phosphonium groups could effectively enhance antifungal activity of the synthesized chitosan derivatives. Meanwhile, it was also found that their antifungal activity was influenced by electron-withdrawing ability of the quaternary phosphonium salts. The synthetic strategy described here could be utilized for the development of chitosan as antifungal biomaterials. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Evaluation of quaternary ammonium halides for removal of methyl iodide from flowing air streams

    International Nuclear Information System (INIS)

    Freeman, W.P.; Mohacsi, T.G.; Kovach, J.L.

    1985-01-01

    The quaternary ammonium halides of several tertiary amines were used as impregnants on activated carbon and were tested for methyl iodide penetration in accordance with test Method A, ASTM D3803, 1979, ''Standard Test Methods for Radio-iodine Testing of Nuclear Grade Gas Phase Adsorbents''. The results suggest that the primary removal mechanism for methyl iodide-131 is isotopic exchange with the quaternary ammonium halide. For example, a 5 wt% impregnation of each of the tetramethyl, tetraethyl, tetrapropyl and tetrabutyl ammonium iodides on activated carbon yielded percent penetrations of 0.47, 0.53, 0.78, and 0.08 respectively when tested according to Method A of ASTM D3803. A sample impregnated with 5% tetramethyl ammonium hydroxide gave a methyl iodide penetration of 64.87%, thus supporting the isotopic exchange mechanism for removal. It has been a generally held belief that the success of tertiary amines as impregnants for radioiodine removal is a result of their ability to complex with the methyl iodide. The results of the work indicates that the superiority of the tertiary amines similar to triethylene diamine and quinuclidine, when compared to their straight chain analogs, is a result of their ease in reacting with methyl iodide-127 to form the quaternary ammonium iodide followed by isotopic exchange

  16. Properties of true quaternary fission of nuclei with allowance for its multistep and sequential character

    Energy Technology Data Exchange (ETDEWEB)

    Kadmensky, S. G., E-mail: kadmensky@phys.vsu.ru; Titova, L. V.; Bulychev, A. O. [Voronezh State University (Russian Federation)

    2015-07-15

    An analysis of basicmechanisms of binary and ternary fission of nuclei led to the conclusion that true ternary and quaternary fission of nuclei has a sequential two-step (three-step) character, where, at the first step, a fissile nucleus emits a third light particle (third and fourth light particles) under shakeup effects associated with a nonadiabatic character of its collective deformation motion, whereupon the residual nucleus undergoes fission to two fission fragments. Owing to this, the formulas derived earlier for the widths with respect to sequential two- and three-step decays of nuclei in constructing the theory of two-step twoproton decays and multistep decays in chains of genetically related nuclei could be used to describe the relative yields and angular and energy distributions of third and fourth light particles emitted in (α, α), (t, t), and (α, t) pairs upon the true quaternary spontaneous fission of {sup 252}Cf and thermal-neutron-induced fission of {sup 235}U and {sup 233}U target nuclei. Mechanisms that explain a sharp decrease in the yield of particles appearing second in time and entering into the composition of light-particle pairs that originate from true quaternary fission of nuclei in relation to the yields of analogous particles in true ternary fission of nuclei are proposed.

  17. Synthesis of inulin derivatives with quaternary phosphonium salts and their antifungal activity.

    Science.gov (United States)

    Chen, Yuan; Tan, Wenqiang; Li, Qing; Dong, Fang; Gu, Guodong; Guo, Zhanyong

    2018-03-13

    Inulin is a kind of renewable and biodegradable carbohydrate with good water solubility and numerous physiological functions. For further utilization of inulin, chemical modification can be applied to improve its bioactivities. In this paper, five novel inulin derivatives were synthesized via chemical modification with quaternary phosphonium salt. Their antifungal activity against three kinds of plant pathogens including Colletotrichum lagenarium, Phomopsis asparagi, and Fusarium oxysporum was assessed with radial growth assay in vitro. Results revealed that all the inulin derivatives exhibited improved antifungal activity compared with inulin. Particularly, inulin modified with triphenylphosphine (TPhPAIL) exhibited the best antifungal activity with inhibitory indices of 80.0%, 78.8%, and 87.4% against Colletotrichum lagenarium, Phomopsis asparagi, and Fusarium oxysporum at 1.0mg/mL respectively. The results clearly showed that chemical modification of inulin with quaternary phosphonium salt could efficiently improve derivatives' antifungal activity. Further analysis of results indicated that the antifungal activity was influenced by alkyl chain length or electron-withdrawing ability of the grafted quaternary phosphonium salts. Longer alkyl chain lengths or the stronger electron-withdrawing groups would lead to enhanced antifungal efficacy. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Late quaternary geology in Desaguadero river basin, San Luis, Argentina

    International Nuclear Information System (INIS)

    Chiesa, J.; Strasser, E.; Gomez, D.; De Miguel, T.

    2007-01-01

    Absolute radiocarbon datings of the sedimentary successions have come to knowledge enabling us to distinguish the Pleistocene deposits from the supra-lying Holocene ones. A palaeo-environmental evolution is proposed considering climatic fluctuations at the time, their relation with the river unloadings of the Andean glaciers and that proposed for the palaeo-lake of Salina del Bebedero. Sediments are described on the basis of a detailed field sampling, textural analysis (sieved and Bouyoucos) and laboratory geo-chemicals. Their interpretation of the geologic evolution is considered to be very important since it is the only river course on this arid-semi-arid region linked to the reduction of glaciers in the Andes. The sedimentary succession is dominated by high percentages of laminated limes and with green-yellowish to greyish-brown-reddish tones deposited in watery environments of low energy such as lacustrine basins and extended plains of flood, which is why the evolution of the deposit is characterized by the contrast of the values of insolubles (clastic sediment and carbonate) versus solubles (insoluble saline). The climatic cycles dominant and proposed for the center-east Argentine region are identified considering the influence of Andean glaciers on the river systems and the water balances in plain semi-arid environments. (author)

  19. Map and Data for Quaternary Faults and Fault Systems on the Island of Hawai`i

    Science.gov (United States)

    Cannon, Eric C.; Burgmann, Roland; Crone, Anthony J.; Machette, Michael N.; Dart, Richard L.

    2007-01-01

    Introduction This report and digitally prepared, GIS-based map is one of a series of similar products covering individual states or regions of United States that show the locations, ages, and activity rates of major earthquake-related features such as faults and fault-related folds. It is part of a continuing the effort to compile a comprehensive Quaternary fault and fold map and database for the United States, which is supported by the U.S. Geological Survey's (USGS) Earthquake Hazards Program. Guidelines for the compilation of the Quaternary fault and fold maps for the United States were published by Haller and others (1993) at the onset of this project. This compilation of Quaternary surface faulting and folding in Hawai`i is one of several similar state and regional compilations that were planned for the United States. Reports published to date include West Texas (Collins and others, 1996), New Mexico (Machette and others, 1998), Arizona (Pearthree, 1998), Colorado (Widmann and others, 1998), Montana (Stickney and others, 2000), Idaho (Haller and others, 2005), and Washington (Lidke and others, 2003). Reports for other states such as California and Alaska are still in preparation. The primary intention of this compilation is to aid in seismic-hazard evaluations. The report contains detailed information on the location and style of faulting, the time of most recent movement, and assigns each feature to a slip-rate category (as a proxy for fault activity). It also contains the name and affiliation of the compiler, date of compilation, geographic and other paleoseismologic parameters, as well as an extensive set of references for each feature. The map (plate 1) shows faults, volcanic rift zones, and lineaments that show evidence of Quaternary surface movement related to faulting, including data on the time of most recent movement, sense of movement, slip rate, and continuity of surface expression. This compilation is presented as a digitally prepared map product

  20. Quaternary nanofossils on the Brazilian continental shelf; Nanofosseis calcarios do quaternario da margem continental brasileira

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, Rogerio Loureiro [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES). Gerencia de Bioestratigrafia e Paleoecologia], E-mail: rlantunes@petrobras.com.br

    2007-07-01

    The study of calcareous nanofossils occurring in the deposits on the Brazilian continental margin began in the late 1960s, undertaken solely by PETROBRAS. Instead of presenting an academic outlook, the purpose of these investigations is first to formulate a biostratigraphic framework to apply to oil well samples. The initial result was the first zoning for the Brazilian continental margin, which considered the deposits formed between the Aptian and Miocene series. Since the 1960s to date, many papers have been written either with details of that original zoning or applying nanofossil biostratigraphy to solve stratigraphic problems. Regardless of all the papers and studies undertaken, little attention has been paid to the Quaternary, since these deposits are normally of no interest to petroleum geology stricto sensu, especially in a large part of the Brazilian margin. On the other hand, there are a few articles and some Master's dissertations and PhD theses that were written and/or are in progress in Brazilian universities. On the other hand, elsewhere in the world, Quaternary nanofossils have been thoroughly investigated in terms of biostratigraphy and paleoceanography. It is, therefore, very clear that there is a gap between what is being done elsewhere in the world and what has been done in Brazil. In fact, this gap is not larger simply because of a few researchers in Brazilian universities who are studying this topic. The intention of this paper is to contribute toward a richer study of Quaternary nanofossils. It, therefore, contains illustrations and taxonomic descriptions of many species observed in the younger strata of the Brazilian margin basins. This article not only aspires to portray and disseminate the potential of nanofossils for the marine Quaternary study but is also an invitation to students (under and post-graduates) and university researchers - an invitation to learn a little more about the subject and spend some time studying these real gems

  1. Aminostratigraphy of surface and subsurface Quaternary sediments, North Carolina coastal plain, USA

    Science.gov (United States)

    Wehmiller, John F.; Thieler, E. Robert; Miller, D.; Pellerito, V.; Bakeman, Keeney V.; Riggs, S.R.; Culver, S.; Mallinson, D.; Farrell, K.M.; York, L.L.; Pierson, J.; Parham, P.R.

    2010-01-01

    The Quaternary stratigraphy and geochronology of the Albemarle Embayment of the North Carolina (NC) Coastal Plain is examined using amino acid racemization (AAR) in marine mollusks, in combination with geophysical, lithologic, and biostratigraphic analysis of 28 rotasonic cores drilled between 2002 and 2006. The Albemarle Embayment is bounded by structural highs to the north and south, and Quaternary strata thin westward toward the Suffolk paleoshoreline, frequently referred to as the Suffolk Scarp. The Quaternary section is up to ∼90 m thick, consists of a variety of estuarine, shelf, back-barrier, and lagoonal deposits, and has been influenced by multiple sea-level cycles. The temporal resolution of the amino acid racemization method is tested statistically and with the stratigraphic control provided by this geologic framework, and it is then applied to the correlation and age estimation of subsurface units throughout the region. Over 500 specimens (primarily Mercenaria and Mulinia) from the subsurface section have been analyzed using either gas chromatographic (GC) or reverse-phase liquid chromatographic (RPLC) techniques. The subsurface stratigraphic data are compared with AAR results from numerous natural or excavated exposures from the surrounding region, as well as results from NC beach collections, to develop a comprehensive aminostratigraphic database for the entire Quaternary record within the NC coastal system. Age mixing, recognized in the beach collections, is also seen in subsurface sections, usually where major seismic reflections or core lithology indicate the presence of stratigraphic discontinuities. Kinetic models for racemization are tested within the regional stratigraphic framework, using either radiocarbon or U-series calibrations or comparison with regional biostratigraphy. Three major Pleistocene aminozones [AZ2, AZ3, and AZ4] are found throughout the region, all being found in superposition in several cores. Each can be subdivided

  2. Plio-Quaternary tectonic evolution off Al Hoceima, Moroccan Margin of the Alboran Basin.

    Science.gov (United States)

    Lafosse, Manfred; d'Acremont, Elia; Rabaute, Alain; Mercier de Lépinay, Bernard; Gorini, Christian; Ammar, Abdellah; Tahayt, Abdelilah

    2015-04-01

    We use data from a compilation of industrial and academic 2D surveys and recent data from MARLBORO-1 (2011), MARLBORO-2 (2012), and SARAS (2012) surveys, which provide high resolution bathymetry and 2D seismic reflexion data. We focus on the key area located south of the Alboran Ridge and the Tofiño Bank, and encompassing the Nekor and Boudinar onshore-offshore basins on the Moroccan side of the Alboran Sea. The Nekor basin is a present pull-apart basin in relay between inherited N050° sinistral strike-slip faults. We consider that these faults define the Principal Displacement Zones (PDZ). The northern PDZ marks the position of the crustal Bokkoya fault, which is connected to the Al-Idrisi Fault Zone en relais with the Adra and Carboneras Fault Zones. On the seabed, right-stepping non-coalescent faults characterize the sinistral kinematics of the northern PDZ and give a general N050° azimuth for the crustal discontinuity. The southern PDZ corresponds to the Nekor fault Zone, a Miocene sinistral strike-slip fault acting as the structural limit of the External Rif. On its eastern edge, the Nekor basin is bounded by the N-S onshore-offshore Trougout fault, connecting the northern and the southern PDZ. The western boundary of the Nekor basin is marked by the Rouadi and El-Hammam Quaternary active N-S normal faults. In the offshore Nekor basin, recent N155° conjugated normal faults affect the seabed. Further east, the Boudinar basin is a Plio-Quaternary uplifted Neogene basin. The northeastern segment of the Nekor fault bounds this basin to the south but is inactive in the Quaternary. Normal east-dipping N150° faults are visible offshore in the continuity of the Boudinar fault. From our perspective, the orientation of major tectonic structures (Bokkoya, Nekor and Carboneras faults and the Alboran ridge) under the present compressive regime due to the Europe/Africa convergence is not compatible with a strike-slip motion. The orientation of the most recent Plio-Quaternary

  3. Novel Multiplex PCR Assay for Detection of Chlorhexidine-Quaternary Ammonium, Mupirocin, and Methicillin Resistance Genes, with Simultaneous Discrimination of Staphylococcus aureus from Coagulase-Negative Staphylococci.

    Science.gov (United States)

    McClure, Jo-Ann; Zaal DeLongchamp, Johanna; Conly, John M; Zhang, Kunyan

    2017-06-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a clinically significant pathogen that is resistant to a wide variety of antibiotics and responsible for a large number of nosocomial infections worldwide. The Agency for Healthcare Research and Quality and the Centers for Disease Control and Prevention recently recommended the adoption of universal mupirocin-chlorhexidine decolonization of all admitted intensive care unit patients rather than MRSA screening with targeted treatments, which raises a serious concern about the selection of resistance to mupirocin and chlorhexidine in strains of staphylococci. Thus, a simple, rapid, and reliable approach is paramount in monitoring the prevalence of resistance to these agents. We developed a simple multiplex PCR assay capable of screening Staphylococcus isolates for the presence of antiseptic resistance genes for chlorhexidine and quaternary ammonium compounds, as well as mupirocin and methicillin resistance genes, while simultaneously discriminating S. aureus from coagulase-negative staphylococci (CoNS). The assay incorporates 7 PCR targets, including the Staphylococcus 16S rRNA gene (specifically detecting Staphylococcus spp.), nuc (distinguishing S. aureus from CoNS), mecA (distinguishing MRSA from methicillin-susceptible S. aureus ), mupA and mupB (identifying high-level mupirocin resistance), and qac and smr (identifying chlorhexidine and quaternary ammonium resistance). Our assay demonstrated 100% sensitivity, specificity, and accuracy in a total of 23 variant antiseptic- and/or antibiotic-resistant control strains. Further validation of our assay using 378 randomly selected and previously well-characterized local clinical isolates confirmed its feasibility and practicality. This may prove to be a useful tool for multidrug-resistant Staphylococcus monitoring in clinical laboratories, particularly in the wake of increased chlorhexidine and mupirocin treatments. Copyright © 2017 American Society for Microbiology.

  4. Geomorphic evidence for Quaternary tectonics on the southern flank of the Yellowstone hotspots from terraces and stream profiles along the Hoback and Snake River

    Science.gov (United States)

    Bufe, Aaron; Pederson, Joel; Tuzlak, Daphnee

    2017-04-01

    The greater Yellowstone region offers a type example of Earth surface response to a mantle anomaly. Motion of the North American plate across the Yellowstone plume over the past 17 Ma is predicted to have produced a wave of transient uplift and extension of the upper crust. In the wake of the plume, the Snake River Plain (SRP) has been subsiding 4-8 km due to a combination of crustal loading by basaltic magmatism and cooling. Studying patterns and rates of Quaternary incision of rivers flowing off the Yellowstone plateau can test models about the distribution and timing of active uplift, subsidence, and faulting, improving our understanding of the geodynamics and the hazards in the region. We present results from surveying and optically stimulated luminescence (OSL) dating of river terraces along the Hoback and upper Snake rivers (western Wyoming and southeastern Idaho), which provide a study transect from the modern Yellowstone hotspot center, across zones of changing fault activity, into the subsiding SRP. Downstream of Palisades Reservoir, dated fill terraces reveal that the Snake River has seen no apparent net incision since 50-60 ky. Moreover, a paleo-channel bed preserved by a 2 My-old basalt flow and exposed <10 m above the modern river suggests that net incision rates averaged over 2 My were <5 m/My. In contrast, upstream of Alpine, we find that three levels of 10-90 ky-old strath terraces record recent incision at rates of 0.1-0.3 mm/y along the deeply incised Alpine Canyon and the Hoback River. Here, the pattern of incision rates appear to be controlled by local baselevel fall along normal faults and we hypothesize that rates of subsidence of the SRP in the Quaternary have been relatively slow (< 0.1 mm/y).

  5. Quaternary basaltic volcanism in the Golden Trout Volcanic Field, southern Sierra Nevada, California

    Science.gov (United States)

    Browne, Brandon L.; Becerra, Raul; Campbell, Colin; Saleen, Phillip; Wille, Frank R.

    2017-09-01

    The Golden Trout Volcanic Field (GTVF) produced the only Quaternary eruptions of mafic magma within the southern Sierra Nevada block. Approximately 38 × 106 m3 of basalt, trachy-basalt, basaltic trachy-andesite, and basaltic andesite (50.1-56.1% SiO2, 1.1-1.9% K2O, and 5.4-9.1% MgO) was erupted from four vents within a 10 km2 portion of the GTVF, which also includes rhyolite domes that are not considered in this study. The vents include, from oldest to youngest: Little Whitney Cone, South Fork Cone, Tunnel Cone, and unglaciated Groundhog Cone. Little Whitney Cone is a 120 m-high pile of olivine-CPX-phyric scoria produced during a Strombolian-style eruption overlying two columnar jointed lava flows. Tunnel Cone formed through a Hawaiian-style eruption along a 400 m-long north-south trending fissure that excavated at least three 25-65 m-wide craters. Crater walls up to 12 m high are composed of plagioclase-olivine-phyric spatter-fed flows that dip radially away from the crater center and crumble to form Tunnel Cone's steep unconsolidated flanks. South Fork Cone is a 170 m-high pile of plagioclase-olivine-phyric scoria that formed during Strombolian to violent Strombolian eruptions. South Fork Cone overlies the South Fork Cone lava, a 9.5 km-long flow ( 12 × 106 km3) that reached the Kern River Canyon to the west. Scoria and airfall deposits originating from South Fork Cone are located up to 2 km from the vent. Groundhog Cone is a 140 m-tall cinder and spatter cone breached on the north flank by a 13 × 106 m3 lava flow that partially buried the South Fork Cone lava and extends 7.5 km west to Kern River Canyon. Incompatible trace element concentrations and ratios show vent-specific trends but are unsystematic when plotted in terms of all mafic GTVF vents, implying that GTVF basalts were derived from a lithospheric mantle source and ascended through thick granitic Sierra Nevada crust as discrete batches that underwent different degrees of crustal contamination

  6. Mapping the North Sea base-Quaternary: using 3D seismic to fill a gap in the geological record

    Science.gov (United States)

    Lamb, Rachel; Huuse, Mads; Stewart, Margaret; Brocklehurst, Simon H.

    2014-05-01

    The identification and mapping of the base-Quaternary boundary in the central parts of the North Sea is problematic due to the change from an unconformable transition between Pliocene and Pleistocene deltaic deposits in the southern North Sea to a conformable one further north (Sejrup et al 1991; Gatliff et al 1994). The best estimates of the transition use seismic reflection data to identify a 'crenulated reflector' (Buckley 2012), or rely on correlating sparse biostratigraphy (Cameron et al 1987). Recent integration of biostratigraphy, pollen analysis, paleomagnetism and amino acid analysis in the Dutch and Danish sectors (Rasmussen et al 2005; Kuhlmann et al 2006) allows greater confidence in the correlation to a regional 3D seismic dataset and show that the base-Quaternary can be mapped across the entire basin. The base-Quaternary has been mapped using the PGS MegaSurvey dataset from wells in the Danish Sector along the initially unconformable horizon and down the delta front into the more conformable basin giving a high degree of confidence in the horizon pick. The mapped horizon is presented here alongside the difference between this new interpretation and the previously interpreted base-Quaternary (Buckley 2012). The revised base-Quaternary surface reaches a depth of 1248 ms TWT or approximately 1120 m (assuming average velocity of 1800 m/s) showing an elongate basin shape that follows the underlying structure of the Central Graben. The difference between the revised base-Quaternary and the traditional base-Quaternary reaches a maximum of over 600 ms TWT or approximately 540 m in the south-west with over 300 ms TWT or approximately 270 m at the Josephine well (56° 36.11'N, 2° 27.09'E) in the centre of the basin. Mapping this new base-Quaternary allows for the interpretation of the paleo-envionrment during the earliest Quaternary. Seismic attribute analysis indicates a deep water basin with sediment deposition from multiple deltas and redistribution by deep

  7. Late Tertiary and Quaternary geology of the Tecopa basin, southeastern California

    Energy Technology Data Exchange (ETDEWEB)

    Hillhouse, J.W.

    1987-12-31

    Stratigraphic units in the Tecopa basin, located in southeastern California, provide a framework for interpreting Quaternary climatic change and tectonism along the present Amargosa River. During the late Pliocene and early Pleistocene, a climate that was appreciably wetter than today`s sustained a moderately deep lake in the Tecopa basin. Deposits associated with Lake Tecopa consists of lacustrine mudstone, conglomerate, volcanic ash, and shoreline accumulations of tufa. Age control within the lake deposits is provided by air-fall tephra that are correlated with two ash falls from the Yellowstone caldera and one from the Long Valley caldera. Lake Tecopa occupied a closed basin during the latter part, if not all, of its 2.5-million-year history. Sometime after 0.5 m.y. ago, the lake developed an outlet across Tertiary fanglomerates of the China Ranch Beds leading to the development of a deep canyon at the south end of the basin and establishing a hydrologic link between the northern Amargosa basins and Death Valley. After a period of rapid erosion, the remaining lake beds were covered by alluvial fans that coalesced to form a pediment in the central part of the basin. Holocene deposits consist of unconsolidated sand and gravel in the Amargosa River bed and its deeply incised tributaries, a small playa near Tecopa, alluvial fans without pavements, and small sand dunes. The pavement-capped fan remnants and the Holocene deposits are not faulted or tilted significantly, although basins to the west, such as Death Valley, were tectonically active during the Quaternary. Subsidence of the western basins strongly influenced late Quaternary rates of deposition and erosion in the Tecopa basin.

  8. Experimental and thermodynamic study of the Mg–Sn–In–Zn quaternary system

    International Nuclear Information System (INIS)

    Wang, Jian; Hudon, Pierre; Kevorkov, Dmytro; Chartrand, Patrice; Jung, In-Ho; Medraj, Mamoun

    2014-01-01

    Highlights: • Phase equilibria in the Mg-rich region of the Mg–Sn–In are determined. • Phase equilibria in the Mg-rich region of the Mg–Sn–Zn are determined. • Evaluation and thermodynamic optimization of the Mg–Sn–In–Zn quaternary system are developed. -- Abstract: Phase equilibria in the Mg-rich region of the Mg–Sn–In (at 415 °C and 330 °C), and Mg–Sn–Zn (at 300 °C) ternary systems were determined by quenching experiments, electron probe micro-analyzer (EPMA), and X-ray diffraction (XRD) techniques. The ternary isoplethal sections with constant 5 In and 10 Sn at.% of Mg–In–Sn system, and 10 Sn at.% of Mg–In–Zn system were determined by differential scanning calorimetry (DSC). No ternary compounds were found in the Mg–Sn–Zn and Mg–Sn–In isothermal sections. Critical evaluation and thermodynamic optimization of the Mg–Sn–In–Zn quaternary system were carried out using CALPHAD (Calculation of Phase Diagrams) technique. The Modified Quasichemical Model in the Pair Approximation (MQMPA) was used for modeling the liquid solution, which exhibits a high degree of short-range ordering behavior. The solid phases were modeled with the Compound Energy Formalism (CEF). All available and reliable experimental data were reproduced within experimental error limits. A self-consistent thermodynamic database was constructed for the Mg–Sn–In–Zn quaternary system, which can be used as a guide for Mg-based alloys development

  9. Quaternary disappearance of tree taxa from Southern Europe: Timing and trends

    Science.gov (United States)

    Magri, Donatella; Di Rita, Federico; Aranbarri, Josu; Fletcher, William; González-Sampériz, Penélope

    2017-05-01

    A hundred pollen and plant macrofossil records from the Iberian Peninsula, Southern France, the Italian Peninsula, Greece and the Aegean, and the southwestern Black Sea area formed the basis for a review of the Quaternary distribution and extirpation of tree populations from Southern Europe. Following a discussion of the caveats/challenges about using pollen data, the Quaternary history of tree taxa has been reconstructed with attention to Taxodium/Glyptostrobus, Sciadopitys, Cathaya, Cedrus, Tsuga, Eucommia, Engelhardia, Carya, Pterocarya, Parrotia, Liquidambar, and Zelkova. The timing of extinction, distributed over the whole Quaternary, appears very diverse from one region to the other, in agreement with current biodiversity in Southern Europe. The geographical patterns of persistence/disappearance of taxa show unexpected trends and rule out a simple North to South and/or West to East trend in extirpations. In particular, it is possible to detect disjunct populations (Engelhardia), long-term persistence of taxa in restricted regions (Sciadopitys), distinct populations/species/genera in different geographical areas (Taxodium type). Some taxa that are still widespread in Europe have undergone extirpation in Mediterranean areas in the lateglacial period and Holocene (Buxus, Carpinus betulus, Picea); they provide an indication of the modes of disappearance of tree populations that may be useful to evaluate correctly the vulnerability of modern fragmented plant populations. The demographic histories of tree taxa obtained by combined palaeobotanical and genetic studies is a most challenging field of research needed not only to assess species/population differentiation, but also to reach a better understanding of extinction processes, an essential task in the current global change scenario.

  10. Review of the tectonic setting of Cretaceous to Quaternary volcanism in northwestern Iran

    Science.gov (United States)

    Azizi, Hossein; Moinevaziri, Hossein

    2009-04-01

    There are three parallel magmatic arcs in the northwest of Iran, of Cretaceous and Eocene-Miocene to Quaternary ages, trending in a NW-SE direction between the Main Zagros Thrust (MZT) in the southwest and the Tabriz Fault in the northeast. In this study, these volcanic belts are referred to as the Sanandaj Cretaceous volcanic (SCV), Sonqor-Baneh volcanic (SBV), and Hamedan-Tabriz volcanic (HTV) belts, respectively. The SCV belt consists mainly of mafic to intermediate submarine rocks with calc-alkaline affinity, and the SBV belt is composed of basalt, gabbro to dioritic bodies, with extrusive to subvolcanic magmatic textures and tholeiitic to alkaline affinity. These extend along the MZT between the Zagros ophiolite in the west and the SCV belt in the east. The HTV belt is part of the Urmieh-Dokhtar Magmatic Arc belt that extends across the Hamedan to Tabriz, and was active in the Miocene to Quaternary. The petrology and geochemistry of the northwestern Iranian volcanic zones indicate that they were generated at an active continental margin. In addition to the volcanic belts, there is a dismembered ophiolite along the MZT from Kermanshah to Turkey, in a NW-SE direction. These ophiolites are remnants of Neo-Tethyan oceanic crust which was obducted over the Arabian passive margin in the late Cretaceous. In this study, we propose that a collision between the Arabian and Iranian plates may have occurred in the middle to late Miocene, and that the Neo-Tethyan oceanic subduction beneath northwestern Iran ceased for a while. As a result, a gap in volcanic activity occurred between the Cretaceous and the Middle Miocene-Quaternary volcanism events. This gap in activity is not observed in southwestern Iran.

  11. Thermoluminescence and new 14C age estimates for late quaternary loesses in southwestern Nebraska

    Science.gov (United States)

    Maat, P.B.; Johnson, W.C.

    1996-01-01

    Loess of late Quaternary age mantles most of Nebraska south of the Platte River Valley. At least five late Quaternary loesses are recognized: from oldest to youngest, one or more undifferentiated pre-lllinoian loesses, the Loveland Loess, the Gilman Canyon Loess, which exhibits a well developed soil and rests unconformably on the Sangamon soil, the Peoria Loess capped by the Brady soil, and the Bignell Loess, which is distributed discontinuously. Previous research shows that the Loveland Loess is Illinoian. the Gilman Canyon Loess and Peoria Loess are Wisconsin, and the Bignell Loess is Holocene. We present here the first thermoluminescence (TL) age estimates and new C ages for these late Quaternary loesses at two key sections in southwestern Nebraska, the Eustis ash pit and the Bignell Hill road cut. TL age estimates from all samples collected from Eustis ash pit and Bignell Hill were internally consistent. TL and C age estimates from these two sections generally agree and support previous age determinations. The TL age estimate on Loveland Loess indicates deposition at 163 ka. TL and radiocarbon age estimates indicate that Oilman Canyon Loess, believed to be deposited during the Farmdale interstade, first began to accumulate at about 40 ka: the lower part of the Gilman Canyon Loess is 36 ka at Eustis and the middle of the unit is 30 ka at Bignell Hill. The lower and upper parts of the Peoria Loess give age estimates of 24 ka and 17 ka, respectively. TL age estimates for deposition of the Bignell Loess are 9 ka near the base, in agreement with radiocarbon age estimates, and 6 ka immediately below the modern soil, substantiating its Holocene age. Comparisons of TL age estimates with ??18O and insolation curves which show loess deposition during interglacial and interstadial as well as glacial periods, indicate that loess deposition on the Great Plains can occur under a variety of climatic conditions.

  12. Transient Quaternary erosion and tectonic inversion of the Northern Range, Trinidad

    Science.gov (United States)

    Arkle, Jeanette C.; Owen, Lewis A.; Weber, John; Caffee, Marc W.; Hammer, Sarah

    2017-10-01

    Cosmogenic 10Be measured in sediments from Northern Range catchments on the island of Trinidad reveals low millennial-scale rates of erosion (average 40 mm/ka) that increase roughly eightfold, from 11 to 92 mm/ka, eastward across the mountain range. These results, in conjunction with an analysis of mountain morphometrics, are consistent with Quaternary east-side-up tilting of the Northern Range, which has occurred recently ( 100 ka). The highest millennial-scale erosion rates coincide spatially with Quaternary east-side surface uplift (albeit not in magnitude), high modern rainfall rates, low topographic relief, and convex longitudinal stream profiles, indicating transient Quaternary erosion. We interpret that hillslope adjustment and erosion of the Northern Range is buffered from climatic and tectonic forcings by dense tropical vegetation cover, thick saprolite, and porous regolith. Compared with longer-term, thermochronology exhumation rates, we document that an order of magnitude deceleration of and reversal in the locus of erosion and exhumation has occurred during the Pliocene to the Holocene. We suggest that these combined data sets highlight distinct syn- and post-collisional phases of Northern Range development that are related to a major change in relative Caribbean-South American plate motion from oblique convergence to transform motion. Oblique collision during the mid-Miocene likely caused relatively higher rates of and asymmetric exhumation of the Northern Range. Post-collisional mountain-scale tilting is likely caused by a combination of crustal extension in the Gulf of Paria and by deep subsurface lithospheric detachment processes that drives dynamic topography.

  13. Quaternary ammonium biocides as antimicrobial agents protecting historical wood and brick.

    Science.gov (United States)

    Rajkowska, Katarzyna; Koziróg, Anna; Otlewska, Anna; Piotrowska, Małgorzata; Nowicka-Krawczyk, Paulina; Brycki, Bogumił; Kunicka-Styczyńska, Alina; Gutarowska, Beata

    2016-01-01

    Quaternary ammonium compounds (QACs) are widely used in disinfection of water, surfaces and instruments as well as in textile, leather and food industries because of their relatively low toxicity, broad antimicrobial spectrum, non-volatility and chemical stability. Due to these advantages, QACs are also used in restoration and can be applied on historical material. The aim of this study was to determine the usefulness of biocides based on quaternary ammonium salts and containing various excipients in the protection of historical materials against microbial growth. The study determined the antimicrobial activity of three biocides against bacteria: Pseudomonas fluorescens, Staphylococcus equorum, Bacillus cereus, Bacillus muralis, Sporosarcina aquimarina and Rhodococcus fascians, and moulds: Chaetomium globosum, Penicillium citreonigrum, Cladosporium cladosporioides I, Acremonium strictum, Aspergillus fumigatus and Cladosporium cladosporioides II, all isolated from historical wood and brick. Staphylococcus equorum, Bacillus cereus, Sporosarcina aquimarina and Rhodococcus fascians bacteria, and Cladosporium cladosporioides I and Acremonium strictum moulds showed high sensitivity to quaternary ammonium biocides. Historical wood can be effectively disinfected by three applications of biocide A (30% v/v) containing dodecyl dimethyl ammonium chloride (DDAC), citric acid, propiconazole and propanol. Disinfection of historical brick can be carried out by three applications of 6% v/v solutions of biocide B (based on DDAC and ethylenediaminetetraacetic acid - EDTA) or biocide C (containing a non-ionic surfactant, DDAC and EDTA). Effective protection of historical building materials against microbial growth for a period of seven days can be achieved by the application of biocide A (30% v/v) on the wood surface and biocide B (6% v/v) on the brick surface.

  14. Geomorphic evidence for enhanced Pliocene-Quaternary faulting in the northwestern Basin and Range

    Science.gov (United States)

    Ellis, Magdalena A; Barnes Jason B,; Colgan, Joseph P.

    2014-01-01

    Mountains in the U.S. Basin and Range Province are similar in form, yet they have different histories of deformation and uplift. Unfortunately, chronicling fault slip with techniques like thermochronology and geodetics can still leave sizable, yet potentially important gaps at Pliocene–Quaternary (∼105–106 yr) time scales. Here, we combine existing geochronology with new geomorphic observations and approaches to investigate the Miocene to Quaternary slip history of active normal faults that are exhuming three footwall ranges in northwestern Nevada: the Pine Forest Range, the Jackson Mountains, and the Santa Rosa Range. We use the National Elevation Dataset (10 m) digital elevation model (DEM) to measure bedrock river profiles and hillslope gradients from these ranges. We observe a prominent suite of channel convexities (knickpoints) that segment the channels into upper reaches with low steepness (mean ksn = ∼182; θref = 0.51) and lower, fault-proximal reaches with high steepness (mean ksn = ∼361), with a concomitant increase in hillslope angles of ∼6°–9°. Geologic maps and field-based proxies for rock strength allow us to rule out static causes for the knickpoints and interpret them as transient features triggered by a drop in base level that created ∼20% of the existing relief (∼220 m of ∼1050 m total). We then constrain the timing of base-level change using paleochannel profile reconstructions, catchment-scale volumetric erosion fluxes, and a stream-power–based knickpoint celerity (migration) model. Low-temperature thermochronology data show that faulting began at ca. 11–12 Ma, yet our results estimate knickpoint initiation began in the last 5 Ma and possibly as recently as 0.1 Ma with reasonable migration rates of 0.5–2 mm/yr. We interpret the collective results to be evidence for enhanced Pliocene–Quaternary fault slip that may be related to tectonic reorganization in the American West, although we cannot rule out climate as a

  15. Late-Quaternary exhumation rates constrained by OSL thermochronometry at the Franz Josef Glacier, New Zealand

    Science.gov (United States)

    Duverger, Arnaud; King, Georgina; Valla, Pierre; Cox, Simon; Herman, Frederic

    2016-04-01

    The Southern Alps of New Zealand are often cited as the primary example of a mountain range that has reached exhumation and topographic steady state, especially on the West Coast where exhumation rates reach up to about 10 mm/yr. However, cyclic climatic changes, throughout the Quaternary period have meant that the Alps cycled between being completely glaciated and ice free. The impact that such glacial cycles may have had on the spatial variability of erosion rates remains poorly constrained. Here we use Optically Stimulated Luminescence (OSL) as a very low temperature thermochronometer to constrain rock cooling histories at 10-100 kyr timescales on samples collected near the Franz Josef glacier. OSL-thermochronometry is based on the amount of electrons accumulated in the lattice defects of natural minerals such as quartz or feldspar, due to the competing effects of charge trapping due to the natural radioactivity within the rock and charge detrapping due to thermal loss during rock exhumation towards the surface. We collected 9 samples along the Waiho valley (crossing the Alpine Fault) and the Franz Josef glacier to quantify late-Quaternary exhumation rates and their potential spatial variations. Bedrock samples have been crushed to extract the light-safe rock interiors which have then been processed to isolate potassium-rich feldspars (K-feldspars). We used the Infra-Red Stimulated Luminescence at 50°C (IRSL50) protocol, including the measurement of the natural IRSL50 trapped charge population and the laboratory characterization of sample-specific thermal and athermal kinetic parameters. Once measured, the luminescence signal can be inverted into cooling histories. We also explored the potential of the recently developed multi-OSL-thermochronometer (King et al., accepted) to better constrain the cooling path. Our first OSL measurements show that samples are not in saturation and thus contain useful thermochronometric information over the last ~100 kyr. Inverse

  16. Ecosystem resilience to abrupt late Quaternary change in continental southern Siberia

    Science.gov (United States)

    Harding, Poppy; Mackay, Anson; Bezrukova, Elena; Shchetnikov, Alexander

    2017-04-01

    Quaternary climate variability is dominated by long term orbital forcing along with abrupt sub-Milankovitch events on the scales of millennia to centuries, driven by internal feedback mechanisms, volcanic forcing and fluctuating solar activity. Although these are well documented in the North Atlantic region, their expression is poorly understood in Siberia, particularly in relation to abrupt climatic events. Siberia has the world's highest level of continentality offering an opportunity to study changes remote from oceanic influences and improving understanding of interactions between the Siberian High and other atmospheric systems including the Aleutian Low, Arctic oscillation and Icelandic Low1 and ENSO2. Understanding of palaeoenvironmental change in Siberia is essential due to the region's high sensitivity to climatic change, with warming rates considerably higher than the global average over the past 50 years3, triggering significant environmental changes, including permafrost degradation, shifts in the forest-steppe biome, increases in forest fires and warming of seasonally ice-covered lakes. Additionally, the region provides essential palaeoenvironmental context for early hominins, for example at globally important sites such as Denisova cave4, and megafauna extinctions5. This presentation outlines ongoing work at Lake Baunt, SE Siberia including: key quaternary climate forcings, the site and its regional context, the key methods and preliminary results. These include a dated record back to ˜30ka BP (based on multiple 14C dates and Bayesian age modelling), multiproxy indicators of palaeoproductivity (e.g. biogenic silica and diatom analyses) and lake mixing regimes (inferred from diatom analyses). Together these highlight several key Quaternary fluctuations potentially correlated to events recorded in Greenland Ice Cores (GS2, GS2.1, GI1, GS1), and these are considered against key Quaternary records including those from nearby Lake Baikal and Hulu Cave in

  17. Asymmetric synthesis of quaternary aryl amino acid derivatives via a three-component aryne coupling reaction

    Directory of Open Access Journals (Sweden)

    Elizabeth P. Jones

    2011-11-01

    Full Text Available A method was developed for the synthesis of α-alkyl, α-aryl-bislactim ethers in good to excellent yields and high diastereoselectivities, consisting of a facile one-pot procedure in which the aryl group is introduced by means of a nucleophilic addition to benzyne and the alkyl group by alkylation of a resultant benzylic anion. Hydrolysis of the sterically less hindered adducts gave the corresponding quaternary amino acids with no racemization, whereas hydrolytic ring opening gave the corresponding valine dipeptides from bulkier bislactims.

  18. Paleoenvironmental changes and influence on Operculodinium centrocarpum during the Quaternary in the Campos Basin, southwestern Brazil

    Science.gov (United States)

    Santos, Alessandra; de Araujo Carvalho, Marcelo; de Oliveira, Antônio Donizeti; Mendonça Filho, João Graciano

    2017-12-01

    The purpose of this paper is to document the changes observed in the Quaternary dinoflagellate assemblages from 80 core samples from the Campos Basin. The Interglacial (Subzone X1), Glacial (Subzones Y5 to Y2), Last Glacial Maximum (Subzone Y1) and Post-Glacial (Zone Z) intervals were identified. High abundance of Operculodinium centrocarpum suggests the warm, high salinity and nutrient-poor water conditions dominated the upper water column of the Campos Basin. The climate and oceanic current dynamic of the continental slope of the Campos Basin appears to has been a significant controlling factor in the distribution of dinocysts, particularly of O. centrocarpum, during the Pleistocene/Holocene transition.

  19. Micropaleontologic record of Quaternary paleoenvironments in the Central Albemarle Embayment, North Carolina, U.S.A.

    Science.gov (United States)

    Culver, Stephen J.; Farrell, Kathleen M.; Mallinson, David J.; Willard, Debra A.; Horton, Benjamin P.; Riggs, Stanley R.; Thieler, E. Robert; Wehmiller, John F.; Parham, Peter; Snyder, Scott W.; Hillier, Caroline

    2011-01-01

    To understand the temporal and spatial variation of eustatic sea-level fluctuations, glacio-hydro-isostacy, tectonics, subsidence, geologic environments and sedimentation patterns for the Quaternary of a passive continental margin, a nearly complete stratigraphic record that is fully integrated with a three dimensional chronostratigraphic framework, and paleoenvironmental information are necessary. The Albemarle Embayment, a Cenozoic regional depositional basin in eastern North Carolina located on the southeast Atlantic coast of the USA, is an ideal setting to unravel these dynamic, interrelated processes.Micropaleontological data, coupled with sedimentologic, chronostratigraphic and seismic data provide the bases for detailed interpretations of paleoenvironmental evolution and paleoclimates in the 90. m thick Quaternary record of the Albemarle Embayment. The data presented here come from a transect of cores drilled through a barrier island complex in the central Albemarle Embayment. This area sits in a ramp-like setting between late Pleistocene incised valleys.The data document the episodic infilling of the Albemarle Embayment throughout the Quaternary as a series of transgressive-regressive (T-R) cycles, characterized by inner shelf, midshelf, and shoreface assemblages, that overlie remnants of fluvial to estuarine valley-fill. Barrier island and marginal marine deposits have a low preservation potential. Inner to mid-shelf deposits of the early Pleistocene are overlain by similar middle Pleistocene shelf sediments in the south of the study area but entirely by inner shelf deposits in the north. Late Pleistocene marine sediments are of inner shelf origin and Holocene deposits are marginal marine in nature. Pleistocene marine sediments are incised, particularly in the northern half of the embayment by lowstand paleovalleys, partly filled by fluvial/floodplain deposits and in some cases, overlain by remnants of transgressive estuarine sediments. The shallowing

  20. Theoretical modelling of quaternary GaInAsSb/GaAs self-assembled quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Llorens, J M; Taboada, A G; Ripalda, J M; Alonso-Alvarez, D; Alen, B; Martin-Sanchez, J; Garcia, J M; Gonzalez, Y [IMM-Instituto de Microelectronica de Madrid, (CNM-CSIC), Isaac Newton 8, PTM, E-28760 Tres Cantos, Madrid (Spain); Sanchez, A M [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Beltran, A M; Galindo, P L; Molina, S I, E-mail: jose.llorens@imm.cnm.csic.e [Universidad de Cadiz, Puerto Real, 11510 Cadiz (Spain)

    2010-09-01

    InAs/GaAs quantum dots exposed to Sb after growth exhibit spectral changes. We study in the present paper an idealized nanostructure consisting of a homogeneous distribution of the quaternary GaInAsSb surrounded by a barrier of GaAs. We find that the valence band offset is a critical parameter in modelling its electronic structure. Depending on this value, we predict a transition from type-I to type-II band alignment at a different Sb concentration. The addition of Sb to reduce the transition energy while keeping a type-I alignment is only of benefit at low Sb concentration.

  1. Electronic, magnetic and transport properties of quaternary (Cu,Ni)MnSb alloys

    Czech Academy of Sciences Publication Activity Database

    Kudrnovský, Josef; Drchal, Václav; Máca, František; Turek, Ilja

    2008-01-01

    Roč. 88, 18-20 (2008), s. 2739-2746 ISSN 1478-6435 R&D Projects: GA ČR GA202/07/0456; GA MŠk OC 150; GA AV ČR IAA100100616 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z20410507 Keywords : density functional theory * exchange interaction * effective Heisenberg model * magnetic disorder * Curie temperature * quaternary Heusler alloys Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.384, year: 2008

  2. Theoretical study of quaternary compounds as thin-film solar cell absorber

    International Nuclear Information System (INIS)

    Su, Huai Wei

    2010-01-01

    Full text : Design of chalcogenide photovoltaic absorbers is carried out systematically through sequential cation mutation, from binary to ternary to quaternary compounds, using first-principles electronic structure calculations. Several universal trends are found for the ternary and two classes of quaternary chalcogenides. For example, the lowest-energy structure always has larger lattice constant a, smaller tetragonal distortion parameter η=c/2a, and larger band gap than the metastable structures for common-row cation mutations. The band gap is reduced during the mutation. The band gap decreases from binary II-VI to ternary I-III-VI 2 are mostly due to the p-d repulsion in the valence band, the decreases from ternary I-III-VI 2 to quaternary I 2 -II-IV-VI 4 chalcogenides are due to the downshift in the conduction band caused by the wavefunction localization on the group IV cation site. It was found that I 2 -II-IV-VI 4 compounds are more stable in the kesterite structure, whereas the widely-assumed stannite structure reported in the literature is most likely due to partial disorder in the I-II layer of the kesterite phase. Among the derived quaternary compounds, Cu 2 ZnSnS 4 (CZTS) is one of the ideal candidate absorber materials for thin-film solar cells with an optimal band gap, high absorption coefficient, abundant elemental components, and is adaptable to various growth techniques. It was performed a series of first-principles electronic structure calculations for CZTS. Also it was found that in the ground state kesterite structure, (i) the chemical potential region that CZTS can form is very small. Therefore, it will be very difficult to obtain high quality stoichiometric CZTS samples; (ii) The dominant p-type acceptor in CZTS is CuZn, however, the associated acceptor level is relatively high, suggesting that p-type doping in CZTS is more difficult than ternary compounds such as CuInSe 2 ; (iii) The formation of the self-compensated defect pair [Cu

  3. The Gediz River fluvial archive: A benchmark for Quaternary research in Western Anatolia

    Science.gov (United States)

    Maddy, D.; Veldkamp, A.; Demir, T.; van Gorp, W.; Wijbrans, J. R.; van Hinsbergen, D. J. J.; Dekkers, M. J.; Schreve, D.; Schoorl, J. M.; Scaife, R.; Stemerdink, C.; van der Schriek, T.; Bridgland, D. R.; Aytaç, A. S.

    2017-06-01

    The Gediz River, one of the principal rivers of Western Anatolia, has an extensive Pleistocene fluvial archive that potentially offers a unique window into fluvial system behaviour on the western margins of Asia during the Quaternary. In this paper we review our work on the Quaternary Gediz River Project (2001-2010) and present new data which leads to a revised stratigraphical model for the Early Pleistocene development of this fluvial system. In previous work we confirmed the preservation of eleven buried Early Pleistocene fluvial terraces of the Gediz River (designated GT11, the oldest and highest, to GT1, the youngest and lowest) which lie beneath the basalt-covered plateaux of the Kula Volcanic Province. Deciphering the information locked in this fluvial archive requires the construction of a robust geochronology. Fortunately, the Gediz archive provides ample opportunity for age-constraint based upon age estimates derived from basaltic lava flows that repeatedly entered the palaeo-Gediz valley floors. In this paper we present, for the first time, our complete dataset of 40Ar/39Ar age estimates and associated palaeomagnetic measurements. These data, which can be directly related to the underlying fluvial deposits, provide age constraints critical to our understanding of this sequence. The new chronology establishes the onset of Quaternary volcanism at ∼1320ka (MIS42). This volcanism, which is associated with GT6, confirms a pre-MIS42 age for terraces GT11-GT7. Evidence from the colluvial sequences directly overlying these early terraces suggests that they formed in response to hydrological and sediment budget changes forced by climate-driven vegetation change. The cyclic formation of terraces and their timing suggests they represent the obliquity-driven climate changes of the Early Pleistocene. By way of contrast the GT5-GT1 terrace sequence, constrained by a lava flow with an age estimate of ∼1247ka, span the time-interval MIS42 - MIS38 and therefore do not

  4. Critical Coalescence Concetration (CCC as a parameter for evaluation of selected quaternary ammonium compounds

    Directory of Open Access Journals (Sweden)

    Danuta Szyszka

    2013-10-01

    Full Text Available The objective of this paper was to determine the Critical Coalescence Concentration (CCC of surfactants such as N(dodecyloxycarboxymethyl N,N,N-(trimethylammonium bromide (DMGM- 12, N-[2-(dodecyoxycarboxyethyl] N,N,N-(trimethylammonium bromide (DMALM-12 and N-[3- (dodecanoyloxycarboxyprophyl] N,N,N-(trimethylammonium bromide (DMPM-11. The surfactants used represent quaternary ammonium compounds containing a hydrophobic moiety with an ester group (commonly known as “esterquats”. The CCC value was determined by analysis of the relationship between concentration of surfactant and average air bubble diameter. The values of the critical coalescence concentration (CCC were estimated using a graphical method.

  5. Megafauna biomass tradeoff as a driver of Quaternary and future extinctions

    OpenAIRE

    Barnosky, Anthony D.

    2008-01-01

    Earth's most recent major extinction episode, the Quaternary Megafauna Extinction, claimed two-thirds of mammal genera and one-half of species that weighed >44 kg between ≈50,000 and 3,000 years ago. Estimates of megafauna biomass (including humans as a megafauna species) for before, during, and after the extinction episode suggest that growth of human biomass largely matched the loss of non-human megafauna biomass until ≈12,000 years ago. Then, total megafauna biomass crashed, because many n...

  6. Quaternary volcanism, tectonics, and sedimentation in the Idaho National Engineering Laboratory area

    Energy Technology Data Exchange (ETDEWEB)

    Hackett, W.R.; Smith, R.P.

    1992-09-01

    In this article, we discuss the regional context and describe localities for a two-day field excursion in the vicinity of the Idaho National Engineering Laboratory (INEL). We address several geologic themes: (1) Late Cenozoic, bimodal volcanism of the Eastern Snake River Plain (ESRP), (2) the regional tectonics and structural geology of the Basin and Range province to the northwest of the ESRP, (3) fluvial, lacustrine, and aeolian sedimentation in the INEL area, and (4) the influence of Quaternary volcanism and tectonics on sedimentation near the INEL.

  7. Quaternary volcanism, tectonics, and sedimentation in the Idaho National Engineering Laboratory area

    Energy Technology Data Exchange (ETDEWEB)

    Hackett, W.R.; Smith, R.P.

    1992-01-01

    In this article, we discuss the regional context and describe localities for a two-day field excursion in the vicinity of the Idaho National Engineering Laboratory (INEL). We address several geologic themes: (1) Late Cenozoic, bimodal volcanism of the Eastern Snake River Plain (ESRP), (2) the regional tectonics and structural geology of the Basin and Range province to the northwest of the ESRP, (3) fluvial, lacustrine, and aeolian sedimentation in the INEL area, and (4) the influence of Quaternary volcanism and tectonics on sedimentation near the INEL.

  8. Study of ternary and quaternary spontaneous fission of sup 2 sup 5 sup 2 Cf with the NESSI detector

    CERN Document Server

    Tishchenko, V G; Hilscher, D; Jahnke, U

    2002-01-01

    Ternary and quaternary spontaneous decay of sup 2 sup 5 sup 2 Cf was studied with the NESSI detector, a combination of two 4 pi detectors for charged particles, neutrons and gamma-rays. The applied method of particle identification by measuring the energies and relative time-of-flights of the decay products is shown to be very effective for the study of rare decay modes. The energy and angular distributions of the decay products, the associated neutron multiplicities, the total energy of the prompt gamma-radiation as well as correlations between the various observables were measured for the first time in a single full-scale experiment. The characteristics of ternary fission known from previous investigations are confirmed in the frame of a methodically independent experiment. Preliminary estimates of the quaternary fission yield are presented. An attempt is made to determine the mechanism of quaternary fission.

  9. The Watergate Learning Center

    Science.gov (United States)

    Training in Business and Industry, 1971

    1971-01-01

    The Watergate Learning Center, recently opened by Sterling Learning Center in Washington, D. C., blueprints the plan established by Sterling and Marriott Hotels for a national chain of learning centers with much the same facilities. (EB)

  10. National Farm Medicine Center

    Science.gov (United States)

    ... ROPS Rebate Skin Cancer Screening Zika Virus National Farm Medicine Center The National Farm Medicine Center was established in 1981 in response to occupational health problems seen in farm patients coming to Marshfield Clinic. The center continues ...

  11. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Education Centers Carbon Monoxide Information Center Carbon Monoxide Information Center En Español The Invisible Killer Carbon monoxide, ... Install one and check its batteries regularly. View Information About CO Alarms Other CO Topics Safety Tips ...

  12. Accredited Birth Centers

    Science.gov (United States)

    ... Administrative Staff Donate Contact MENU CLOSE back Accredited Birth Centers You are here: Home Accredited Birth Centers ... not CABC-accredited. How do you find a birth center here? Skip Instructions! Get to the Map… ...

  13. Children's cancer centers

    Science.gov (United States)

    Pediatric cancer center; Pediatric oncology center; Comprehensive cancer center ... Treating childhood cancer is not the same as treating adult cancer. The cancers are different. So are the treatments and the ...

  14. The quaternary lidocaine derivative, QX-314, exerts biphasic effects on transient receptor potential vanilloid subtype 1 channels in vitro

    DEFF Research Database (Denmark)

    Rivera-Acevedo, Ricardo E; Pless, Stephan Alexander; Ahern, Christopher A

    2011-01-01

    BACKGROUND: Transient receptor potential vanilloid subfamily member 1 (TRPV1) channels are important integrators of noxious stimuli with pronounced expression in nociceptive neurons. The experimental local anesthetic, QX-314, a quaternary (i.e., permanently charged) lidocaine derivative, recently...... concentrations (less than 1 mM), QX-314 potently inhibited capsaicin-evoked TRPV1 currents with an IC₅₀ of 8.0 ± 0.6 μM. CONCLUSIONS: The results of this study show that the quaternary lidocaine derivative QX-314 exerts biphasic effects on TRPV1 channels, inhibiting capsaicin-evoked TRPV1 currents at lower...

  15. Impact of Quaternary climatic changes and interspecific competition on the demographic history of a highly mobile generalist carnivore, the coyote.

    Science.gov (United States)

    Koblmüller, Stephan; Wayne, Robert K; Leonard, Jennifer A

    2012-08-23

    Recurrent cycles of climatic change during the Quaternary period have dramatically affected the population genetic structure of many species. We reconstruct the recent demographic history of the coyote (Canis latrans) through the use of Bayesian techniques to examine the effects of Late Quaternary climatic perturbations on the genetic structure of a highly mobile generalist species. Our analysis reveals a lack of phylogeographic structure throughout the range but past population size changes correlated with climatic changes. We conclude that even generalist carnivorous species are very susceptible to environmental changes associated with climatic perturbations. This effect may be enhanced in coyotes by interspecific competition with larger carnivores.

  16. Womens Business Center

    Data.gov (United States)

    Small Business Administration — Women's Business Centers (WBCs) represent a national network of nearly 100 educational centers throughout the United States and its territories, which are designed...

  17. Deployment of an in-house designed training process in a quaternary care hospital.

    Science.gov (United States)

    Kumar, Ajit; Bhatia, Saurabh; Chiang, I-Jen

    2013-01-01

    Healthcare providers, such as doctors and nurses, have been famous for high resistance to change. A careful change management plan, particularly training process, is utmost necessary. A quaternary care hospital in India changed its system, from manual to Electronic Medical Record/Health Information System (EMR/HIS). The hospital management wanted to train its 4000 diverse end-users on the EMR/HIS in two months' time. This paper describes an in-house designed training process and its deployment in the given healthcare organizational settings. We designed a training process named DRIPDA. The training process was deployed to train 4000 end-users of EMR/HIS, in the quaternary care hospital. Various factors, such as methods and tools of training, constraints of trainees, trainers, and organization were considered while deploying the training process. The effectiveness of the DRIPDA was assessed using the Kirkpatrick model. End-users received training on the new system only in 25% of estimated time and 28% of the projected expense, without having any distraction in their usual workflow, or any productivity loss. We found that the DRIPDA training process could train all employees effectively and efficiently. A decent training process can help in managing the change, thereby reduce the training time and cost.

  18. Late Quaternary palaeoenvironmental reconstruction of sediment drift accumulation in the Malta Graben (central Mediterranean Sea)

    Science.gov (United States)

    Ferraro, Serena; Sulli, Attilio; Di Stefano, Enrico; Giaramita, Luigi; Incarbona, Alessandro; Graham Mortyn, P.; Sprovieri, Mario; Sprovieri, Rodolfo; Tonielli, Renato; Vallefuoco, Mattia; Zizzo, Elisabetta; Tranchida, Giorgio

    2018-03-01

    The Malta Graben is a deep tectonic depression in the Sicily Channel, bounded by NW-SE normal faults and filled by thick Pliocene-Quaternary deposits. A previous analysis of a giant piston core (LC09) from the Malta Graben had revealed a wide range of sedimentary features (carbonate turbidites, bioturbated mud and scours), although the chronostratigraphic constraint of the stacking pattern has remained elusive. After establishing a reliable chronological framework based on seven radiocarbon dates for a shorter core from the Malta Graben (ANSIC03-735), a down-core analysis of planktonic foraminifer and coccolith abundance, stable isotopes and sediment grain size was carried out. Since the last glacial maximum, palaeoenvironmental conditions (surface fertility and deep chlorophyll maximum during the last glacial and the Younger Dryas; warm and oligotrophic water masses, with a deep nutricline and intense winter mixing during the Holocene) as well as selected calcareous plankton taxa trends and peaks seem to be similar to those reported for other central and western Mediterranean sites, possibly in spite of a unique response of these areas to late Quaternary climatic fluctuations. Four distinct layers, each tens of centimetres thick, are barren of foraminifers but not of coccoliths. Morphobathymetric data as well as new high-resolution and high-penetration seismic profiles show that prolonged contouritic activity has persisted on the western side of the Malta Graben. It is thus likely that layers barren of foraminifers are due to the overflow of fine-grained (clayey) material beyond drift channel dikes.

  19. In Vitro Activity of Quaternary Ammonium Surfactants against Streptococcal, Chlamydial, and Gonococcal Infective Agents.

    Science.gov (United States)

    Inácio, Ângela S; Nunes, Alexandra; Milho, Catarina; Mota, Luís Jaime; Borrego, Maria J; Gomes, João P; Vaz, Winchil L C; Vieira, Otília V

    2016-06-01

    Quaternary ammonium compounds (QAC) are widely used, cheap, and chemically stable disinfectants and topical antiseptics with wide-spectrum antimicrobial activities. Within this group of compounds, we recently showed that there are significant differences between the pharmacodynamics of n-alkyl quaternary ammonium surfactants (QAS) with a short (C12) alkyl chain when in vitro toxicities toward bacterial and mammalian epithelial cells are compared. These differences result in an attractive therapeutic window that justifies studying short-chain QAS as prophylactics for sexually transmitted infections (STI) and perinatal vertically transmitted urogenital infections (UGI). We have evaluated the antimicrobial activities of short-chain (C12) n-alkyl QAS against several STI and UGI pathogens as well as against commensal Lactobacillus species. Inhibition of infection of HeLa cells by Neisseria gonorrhoeae and Chlamydia trachomatis was studied at concentrations that were not toxic to the HeLa cells. We show that the pathogenic bacteria are much more susceptible to QAS toxic effects than the commensal vaginal flora and that QAS significantly attenuate the infectivity of N. gonorrhoeae and C. trachomatis without affecting the viability of epithelial cells of the vaginal mucosa. N-Dodecylpyridinium bromide (C12PB) was found to be the most effective QAS. Our results strongly suggest that short-chain (C12) n-alkyl pyridinium bromides and structurally similar compounds are promising microbicide candidates for topical application in the prophylaxis of STI and perinatal vertical transmission of UGI. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  20. Eolian sediment responses to late Quaternary climate changes: Temporal and spatial patterns in the Sahara

    Science.gov (United States)

    Swezey, C.

    2001-01-01

    This paper presents a compilation of eolian-based records of late Quaternary climate changes in the Sahara. Although the data are relatively sparse, when viewed as a whole, they reveal a general pattern of widespread eolian sediment mobilization prior to 11,000 cal. years BP, eolian sediment stabilization from 11,000 to 5000 cal. years BP, and a return to widespread eolian sediment mobilization after 5000 cal. years BP. Furthermore, an eolian-based record from southern Tunisia reveals the existence of millennial-scale changes in eolian sediment behavior. These millennial-scale variations provide examples of eolian sediment responses to climate changes at a scale intermediate between seasonal and orbital ('Milankovitch') changes, and they are also coincident with abrupt atmospheric and oceanic changes. The general synchroneity of the eolian stratigraphic records and their coincidence with various oceanic and atmospheric changes suggest that global forcing mechanisms have influenced late Quaternary eolian sediment behavior in the Sahara. ?? 2001 Elsevier Science B.V.

  1. Structural contour, isopach and feature maps of quaternary sediments in Western Lake Ontario

    International Nuclear Information System (INIS)

    Lewis, C.F.M.; King, E.L.; Todd, B.J.; Blasco, S.M.

    1995-06-01

    A systematic high-resolution acoustic reconnaissance survey of Quaternary sediments (> 50 m thick, in places) and the underlying bedrock surface was completed for western Lake Ontario between Burlington and Port Hope, Ontario, to determine if geophysical lineaments through the area of Pickering and Darlington nuclear power stations are potentially seismically active. A total of 2530 line-km of data were obtained along N-S and E-W lines spaced 10 and 5 km respectively, using a high-resolution subbottom profiler (boomer and IKB-SEISTEC), a 100 kHz sidescan sonar (150-m range) with 3.5 kHz profiler, a 10 or 40 cu. in. sleeve gun seismic reflection system, and, intermittently, a marine magnetometer. Six piston cores up to 15-m long were collected to compare sediment lithology with key regional seismic reflectors. Sediments deposited over the past 13,000 years were imaged with vertical resolution in the order of 10-30 cm just below the lakebed and less than 1 m at the bedrock surface; resolution for the sleeve gun system is approximately 3-5 m. Digital processing and rescaling of selected seismic profiles aided interpretation. Structural contour maps for three Quaternary sequence boundaries and the bedrock surface were generated together with the related sequence isopach maps. Three additional maps portray lakebed features identified on sidescan sonar records and subsurface features identified on seismic profiles. All maps are at 1:250,000 scale. (author). 2 tabs., 48 figs., 12 maps

  2. Quaternary-geological results and problems of the Gorleben project for final storage of radioactive waste

    International Nuclear Information System (INIS)

    Duphorn, K.

    1984-01-01

    The measured results and the ground-water flow models elaborated by the Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover, show that the ground-water flows relatively fast in the high-permeability quaternary sands and gravels of the Gorleben channel down to the caprock. This accounts for the current subrosion rate which has been determined to be up to 1 mm per annum, so that a subrosion volume of up to 10.000 m 3 a year is to be expected, which means that ground-water flow from the channel bottom to the soil surface is expected to take a period of only 600 up to 3700 years. These quaternary-hydrogeological results give reason to doubt whether the model of the geologic multi-barriers, according to which a protective function is attributed to the ''caprock barrier'', can really be applied. The results show that the ''salt-bed barrier'' at the Gorleben site is geologically unstable and endangered by subrosion, which is reason enough to likewise question the protective effect of this salt formation in the long run. (orig./HP) [de

  3. Surface Induced Dissociation Yields Quaternary Substructure of Refractory Noncovalent Phosphorylase B and Glutamate Dehydrogenase Complexes

    Science.gov (United States)

    Ma, Xin; Zhou, Mowei; Wysocki, Vicki H.

    2014-03-01

    Ion mobility (IM) and tandem mass spectrometry (MS/MS) coupled with native MS are useful for studying noncovalent protein complexes. Collision induced dissociation (CID) is the most common MS/MS dissociation method. However, some protein complexes, including glycogen phosphorylase B kinase (PHB) and L-glutamate dehydrogenase (GDH) examined in this study, are resistant to dissociation by CID at the maximum collision energy available in the instrument. Surface induced dissociation (SID) was applied to dissociate the two refractory protein complexes. Different charge state precursor ions of the two complexes were examined by CID and SID. The PHB dimer was successfully dissociated to monomers and the GDH hexamer formed trimeric subcomplexes that are informative of its quaternary structure. The unfolding of the precursor and the percentages of the distinct products suggest that the dissociation pathways vary for different charge states. The precursors at lower charge states (+21 for PHB dimer and +27 for GDH hexamer) produce a higher percentage of folded fragments and dissociate more symmetrically than the precusors at higher charge states (+29 for PHB dimer and +39 for GDH hexamer). The precursors at lower charge state may be more native-like than the higher charge state because a higher percentage of folded fragments and a lower percentage of highly charged unfolded fragments are detected. The combination of SID and charge reduction is shown to be a powerful tool for quaternary structure analysis of refractory noncovalent protein complexes, as illustrated by the data for PHB dimer and GDH hexamer.

  4. Quaternary deposits and weathered bedrock material as a source of dangerous radon emissions in Estonia

    Directory of Open Access Journals (Sweden)

    Petersell Valter

    2015-06-01

    Full Text Available The risk of dangerous radon emissions in Estonia is high, being among the highest in Europe. In almost 33 per cent of Estonian land area, the content of radon in soil-contained air exceeds the safe limit for unrestricted construction (50 kBq/m3. In such high radon-risk areas the concentration of radon in soil-contained air ranges from 50 to 400 kBq/m3, in a few cases reaching up to 2,100 kBq/m3 exceeding the permitted level for residential areas. The situation is particularly serious in the northernmost part of the country, where uranium-rich graptolite argillite (Dictyonema shale and the Obolus phosphorite are close to ground surface and their particles are constituent parts of Quaternary deposits. Radon emissions from bedrock have been investigated in detail, but to date Quaternary strata as a source of radon emissions are poorly studied. According to our measurements the highest concentrations of radon are related to tills containing clasts and fines of graptolite argillite and phosphorite. Glacial deposits include also granitoidal material, containing U, Th and K, which have been transported by glaciers from the outcrop areas of crystalline basement rocks in Finland and the Gulf of Finland. Due to weathering, outwash and repeated redeposition other genetic types are poorer in radioactive elements and they are weaker sources of radon.

  5. Testing MODFLOW-LGR for simulating flow around Buried Quaternary valleys - synthetic test cases

    DEFF Research Database (Denmark)

    Vilhelmsen, Troels Norvin; Christensen, Steen

    In Denmark the water supply is entirely based on ground water. In some parts of the country these resources are found in buried quaternary tunnel valleys. Intensive mapping has shown that the valleys typically have a complex internal hydrogeology with multiple cut and ­fill structures. The admini......In Denmark the water supply is entirely based on ground water. In some parts of the country these resources are found in buried quaternary tunnel valleys. Intensive mapping has shown that the valleys typically have a complex internal hydrogeology with multiple cut and ­fill structures....... The administration of groundwater resources has been based on simulations using regional scale groundwater models. However, regional scale models have difficulties with accurately resolving the complex geology of the buried valleys, which bears the risk of poor model predictions of local scale effects of groundwater...... abstraction. To enable effective administration of the groundwater resources new methods need to be investigated to improve simulation of local scale flow in buried valleys that interact with surrounding regional groundwater systems. The purpose of this synthetic case study is to test the Local Grid Re...

  6. Hydrogeochemical processes in the Plio-Quaternary Remila aquifer (Khenchela, Algeria)

    Science.gov (United States)

    Aouidane, Laiche; Belhamra, Mohamed

    2017-06-01

    The Remila Plain is a synclinal structure in northeast Algeria, situated within a semi-arid climate zone and composed of Mio-Pliocene-Quaternary deposits. Within the syncline, the Plio-Quaternary aquifer is the main source of drinking water for cattle and for agricultural irrigation water. This work aims to investigate the origin of groundwater mineralization and to identify the primary hydrogeochemical processes controlling groundwater evolution in the Remila aquifer. A total of 86 water samples from boreholes were analyzed for major, minor and stable isotopes (18O, 2H) over three seasons: first during low water levels in 2013, second during high water levels in 2014 and third for stable isotopes during low water levels in 2015. The analysis showed that the aquifer is controlled by five principal geochemical processes: (I) the dissolution of evaporite rocks, (II) cation exchange and reverse exchange reactions, (III) congruent dissolution of carbonates (calcite, dolomite) coupled with the dissolution of gypsum and calcite precipitation, (IV) sulfate reduction under anaerobic conditions, and (V) saltwater intrusion in the northeastern Sabkha plains. The 18O and deuterium concentrations in groundwater are very low, indicating that the aquifer is recharged by evaporated rainfall originating from the north slope of the Aurès Mountains which confirms that the aquifer is recharged in the southern part of the plain.

  7. Effect of a novel quaternary ammonium silane on dentin protease activities.

    Science.gov (United States)

    Umer, D; Yiu, C K Y; Burrow, M F; Niu, L-N; Tay, F R

    2017-03-01

    Demineralized dentin collagen release C-terminal cross-linked telopeptide (ICTP) and C-terminal peptide (CTX) during degradation. The present study evaluated the effects of dentin pre-treatment with K21, a quaternary ammonium silane (QAS), on matrix metalloproteinase (MMP) and cathepsin K-mediated collagen degradation. Dentin beams were demineralized with 10% H 3 PO 4 for 24h. After baseline dry mass measurements, the beams were divided into 5 groups (N=10) according to protease inhibitors. The beams were pre-treated for 2min with 2% chlorhexidine (CHX), 2%, 5% or 10% QAS; no pre-treatment was performed for the control group. The beams were subsequently incubated in calcium- and zinc-containing medium for 3, 7 or 14days, after which changes in dry mass were measured and incubation media were examined for ICTP and CTX release. The MMP-2 and cathepsin K activities in QAS-treated dentin powder were also quantified using ELISA. The two factors (disinfectants and time) had a significant effect on dry mass loss, ICTP and CTX release (psilane increases the resistance of dentin collagen to degradation by inhibiting endogenous matrix metalloproteinases and cysteine cathepsins. The quaternary ammonium silane cavity disinfectant is promising for use as a protease inhibitor to improve durability of resin-dentin bonds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Radiocarbon ages of upper quaternary deposit in central Nepal and their geomorphological significance

    International Nuclear Information System (INIS)

    Yamanaka, Hidetsugu

    1982-01-01

    The author visited Nepal from October, 1980, to February, 1981, investigated the geomorphology and upper Quaternary geology in Central Nepal, and collected a number of samples for radiocarbon dating. After returning to his university, he dated ten samples by himself. In Nepal, radiocarbon age has been scarcely reported as yet, besides in Kathmandu valley. Therefore, the author's ten data of the age are very important for the late Quaternary chronological study of Nepal Himalayas. In this paper, the author describes sampling localities and horizons, dating results and their geomorphological significance. These ten samples included Pokhara valley, Marsyandi Kohla, Modi Khola, Madi Khola and Muktinath samples. Some conclusion was derived as for the geomorphological development in central Nepal: The last Himalayan glacial age had already ended before 9,000 yr BP (years before A.D. 1950); In the Midland region, from 4,300 to 600 yr BP, some large-scale mudflows broke out nearly contemporaneously in the upper valleys, and they flowed down torrentially and catastrophically to deposit in the middle course of rivers. But the cause of vast quantity of material suddenly brought down from the Great Himalayas has been still left unexplained. The conclusion like this also was able to be applied to the middle Marsyandi Khola and the Pokhara valley. The wide-spread schema that the river was aggraded in the glacial age and degraded in the interglacial age may not be applicable to the rivers in the Midland region of Nepal Himalayas. (Wakatsuki, Y.)

  9. Global late Quaternary megafauna extinctions linked to humans, not climate change.

    Science.gov (United States)

    Sandom, Christopher; Faurby, Søren; Sandel, Brody; Svenning, Jens-Christian

    2014-07-22

    The late Quaternary megafauna extinction was a severe global-scale event. Two factors, climate change and modern humans, have received broad support as the primary drivers, but their absolute and relative importance remains controversial. To date, focus has been on the extinction chronology of individual or small groups of species, specific geographical regions or macroscale studies at very coarse geographical and taxonomic resolution, limiting the possibility of adequately testing the proposed hypotheses. We present, to our knowledge, the first global analysis of this extinction based on comprehensive country-level data on the geographical distribution of all large mammal species (more than or equal to 10 kg) that have gone globally or continentally extinct between the beginning of the Last Interglacial at 132,000 years BP and the late Holocene 1000 years BP, testing the relative roles played by glacial-interglacial climate change and humans. We show that the severity of extinction is strongly tied to hominin palaeobiogeography, with at most a weak, Eurasia-specific link to climate change. This first species-level macroscale analysis at relatively high geographical resolution provides strong support for modern humans as the primary driver of the worldwide megafauna losses during the late Quaternary.

  10. Partial delignification of wood and membrane preparation using a quaternary ammonium ionic liquid

    Science.gov (United States)

    Miao, Jiaojiao; Yu, Yongqi; Jiang, Zeming; Tang, Lan; Zhang, Liping

    2017-03-01

    This work determined that southern yellow pine wood can almost be completely dissolved in the quaternary ammonium ionic liquid tetrabutylammonium acetate with dimethyl sulfoxide (in a 2:8 mass ratio), after minimal grinding, upon heating at 85 °C for three dissolution/reconstitution cycles, each 1.5 h. Approximately 34.6% of the native lignin and 67.4% of the native carbohydrates present in the original wood can subsequently be extracted, respectively, and were assessed. A gradual decrease in lignin with increased extraction cycles resulted in increased crystallinity index of the cellulose II in the cellulose-rich residue, as confirmed by X-ray diffraction. An increasingly homogeneous macrostructure in the cellulose-rich residue was also evident from scanning electron microscopy images. Membranes cast directly from either wood or cellulose-rich residue solutions in the same tetrabutylammonium acetate/dimethyl sulfoxide system, were prepared using a papermaking-like process. Morphological and mechanical studies indicated that lignin extraction made the membranes more uniform and flexible. Systematic increases in the fibril lengths and orientations of the recovered materials were also found with decreasing lignin contents on the basis of atomic force microscopy analysis. This work demonstrates that relatively efficient partial separation of pine wood and subsequent membrane preparation are possible using a quaternary ammonium ionic liquid.

  11. Dental primer and adhesive containing a new antibacterial quaternary ammonium monomer dimethylaminododecyl methacrylate

    Science.gov (United States)

    Cheng, Lei; Weir, Michael D.; Zhang, Ke; Arola, Dwayne D.; Zhou, Xuedong; Xu, Hockin H. K.

    2013-01-01

    Objectives The main reason for restoration failure is secondary caries caused by biofilm acids. Replacing the failed restorations accounts for 50–70% of all operative work. The objectives of this study were to incorporate a new quaternary ammonium monomer (dimethylaminododecyl methacrylate, DMADDM) and nanoparticles of silver (NAg) into a primer and an adhesive, and to investigate their effects on antibacterial and dentin bonding properties. Methods Scotchbond Multi-Purpose (SBMP) served as control. DMADDM was synthesized and incorporated with NAg into primer/adhesive. A dental plaque microcosm biofilm model with human saliva was used to investigate metabolic activity, colony-forming units (CFU), and lactic acid. Dentin shear bond strengths were measured. Results Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the new DMADDM were orders of magnitude lower than those of a previous quaternary ammonium dimethacrylate (QADM). Uncured primer with DMADDM had much larger inhibition zones than QADM (pcontrol. Incorporation of DMADDM and NAg into primer/adhesive did not adversely affect dentin bond strength. Conclusions A new antibacterial monomer DMADDM was synthesized and incorporated into primer/adhesive for the first time. The bonding agents are promising to combat residual bacteria in tooth cavity and invading bacteria at tooth-restoration margins to inhibit caries. DMADDM and NAg are promising for use into a wide range of dental adhesive systems and restoratives. PMID:23353068

  12. Natural responses to Quaternary climatic change in the Nevada Test Site region

    International Nuclear Information System (INIS)

    Gibson, J.D.

    1993-01-01

    Migration of hazardous contaminants within geologic settings depends on natural processes. Climatic fluctuations can affect the magnitudes and rates of many of these processes. In any long-term environmental evaluation of natural processes, responses to climatic change must be considered. Four generalized categories of natural responses to Quaternary climatic change are recognized for the Nevada Test Site (NTS) region of southwestern Nevada and adjacent California: (1) biologic, (2) geomorphic, (3) hydrologic (including surface and subsurface) and (4) pedologic/diagenetic. Specific examples that correspond to the four categories illustrate the broad range of complex natural processes the are affected by climatic change. These responses dictate the potential effects of climatic change on contaminant transport, effects that are being examined by existing and planned environmental-restoration and waste-management programs within the region. Regulatory requirements for many of these programs include long-term (>10,000-year) waste isolation because of radiologic components. The purpose here is not to be exhaustive in documenting all known natural responses to climatic change in the NTS region, but rather to give a flavor of the scope of interdisciplinary and interrelated fields of Quaternary science that must be considered in evaluating the possible effects of climatic change on long-term environmental programs

  13. IODP Expeditions 303 and 306 Monitor Miocene- Quaternary Climate in the North Atlantic

    Directory of Open Access Journals (Sweden)

    Carlos Alvarez-Zarikian

    2006-03-01

    Full Text Available Introduction The IODP Expeditions 303 and 306 drilling sites were chosen for two reasons: (1 to capture Miocene-Quaternary millennial-scale climate variability in sensitive regions at the mouth of the Labrador Sea and in the North Atlantic icerafted debris (IRD belt (Ruddiman et al., 1977, and (2 to provide the sedimentary and paleomagnetic attributes, including adequate sedimentation rates, for constructinghigh-resolution isotopic and magnetic stratigraphies.High accumulation rates, reaching 20 cm ky-1, permit the study of millennial-scale variations in climate and in the Earth's magnetic fi eld over the past several million years, when the amplitude and frequency of climate variability changed substantially. Shipboard logging and scanning data (magnetic susceptibility and remanence, density, natural gamma radiation, digital images and color refl ectance and post-expedition x-ray fl uorescence (XRF scanning datahave revealed that the sediment cores recovered on Expeditions 303 and 306 contain detailed histories of millennial-scale climate and geomagnetic fi eld variability throughout the late Miocene to Quaternary epochs. The climate proxies will be integrated with paleomagnetic data to place the records of millennial-scale climate change into a high resolution stratigraphy based on oxygen isotope andrelative paleomagnetic intensity (RPI. The paleomagnetic record of polarity reversals, excursions and RPI in these cores is central to the construction of the stratigraphic template and will provide detailed documentation of geomagnetic fi eld behavior.

  14. Polydimethylsiloxane-polymethacrylate block copolymers tethering quaternary ammonium salt groups for antimicrobial coating

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Xiaoshuai; Li, Yancai; Zhou, Fang; Ren, Lixia; Zhao, Yunhui, E-mail: zhaoyunhui@tju.edu.cn; Yuan, Xiaoyan

    2015-02-15

    Highlights: • A series of PDMS-b-QPDMAEMA block copolymers were synthesized via RAFT polymerization. • The composition and morphology of the copolymer films strongly depended on the content of QPDMAEMA. • Migration of QPDMAEMA blocks toward surface was promoted when contacting with water. • Heterogeneous film surfaces with higher N{sup +} content exhibited more obvious antimicrobial activity. - Abstract: Block copolymers PDMS-b-PDMAEMA were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization involving N,N-dimethylaminoethyl methacrylate (DMAEMA) by using poly(dimethylsiloxane) (PDMS) macro-chain transfer agent. And, the tertiary amino groups in PDMAEMA were quaternized with n-octyliodide to provide quaternary ammonium salts (QPDMAEMA). The well-defined copolymers generated composition variation and morphology evolvement on film surfaces, which were characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and contact angle measurements. The results indicated that the enrichment of QPDMAEMA brought about lower elemental ratios of Si/N on the film surfaces. The surface morphologies evolved with the variations of QPDMAEMA content, and the variation trend of film roughness was exactly opposite to that of water contact angle hysteresis. With regard to structure-antimicrobial relationships, the copolymer films had more evident antimicrobial activity against Gram-positive, Bacillus subtilis, and the surfaces with heterogeneous morphology and higher N{sup +} content presented better antimicrobial activity. The functionalized copolymers based PDMS and quaternary ammonium salts materials have the potential applications as antimicrobial coatings.

  15. β-CD assisted dissolution of quaternary ammonium permanganates in aqueous medium.

    Science.gov (United States)

    Bank, Suraj Prakash; Guru, Partha Sarathi; Dash, Sukalyan

    2014-10-13

    The non-polar internal cavity of β-cyclodextrin (β-CD) has been exploited for the entrapment of the hydrophobic tails of two water insoluble quaternary ammonium permanganates (QAPs): cetyltrimethylammonium permanganate (CTAP) and tetrabutylammonium permanganate (TBAP), for solubilization in aqueous medium. The solubilization and organizational behavior of the QAPs in aqueous β-CD solution have been determined from the comparison of their rates of self-oxidation in presence and in absence of β-CD. Effect of QAP concentration on their observed rate constants (k(obs)) at a fixed β-CD concentration, phase solubility analysis in varying β-CD concentration, impact of quaternary ammonium bromides (QABs) on the kobs values of CTAP and TBAP at fixed QAP and β-CD concentrations, and the temperature effect have been reported. A scheme to explain the solvation of QAPs in aqueous β-CD has been proposed based on dynamic light scattering (DLS) analysis of the samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Bohr effect of human hemoglobin: Separation of tertiary and quaternary contributions based on the Wyman equation.

    Science.gov (United States)

    Okonjo, Kehinde Onwochei

    2017-09-01

    As a prelude to separating tertiary from quaternary structure contributions to the Bohr effect, we employed the Wyman equation to analyze Bohr data for human hemoglobin to which 2,3-bisphosphoglycerate, 2,3-BPG, is bound. Changes in the pK a s of the histidine Bohr groups result in a net reduction of their contributions to the Bohr effect at pH 7.4 compared to their contributions in stripped hemoglobin. The non-histidine 2,3-BPG binding groups - the β-chain terminal amino group and Lys82β - make negative and positive contributions, respectively, to the Bohr effect. The final result is that the Bohr effect at physiological pH is higher for 2,3-BPG bound compared to stripped hemoglobin. Contributions linked to His2β, His77β and His143β enable us to separate tertiary from quaternary Bohr contributions in stripped and in 2,3-BPG bound hemoglobin. Both contributions serve to make the Bohr effect for 2,3-BPG bound hemoglobin higher than for stripped hemoglobin at physiological pH. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. The Lathrop Wells volcanic center: Status of field and geochronology studies

    Energy Technology Data Exchange (ETDEWEB)

    Crowe, B.; Morley, R. [Los Alamos National Lab., Las Vegas, NV (United States); Wells, S. [California Univ., Riverside, CA (United States); Geissman, J.; McDonald, E.; McFadden, L.; Perry, F. [New Mexico Univ., Albuquerque, NM (United States); Murrell, M.; Poths, J. [Los Alamos National Lab., NM (United States); Forman, S. [Ohio State Univ., Columbus, OH (United States)

    1993-03-01

    The Lathrop Wells volcanic center is located 20 km south of the potential Yucca Mountain site, at the south end of the Yucca Mountain range. It has long been recognized as the youngest basalt center in the region. However, determination of the age and eruptive history of the center has proven problematic. The purpose of this paper is to describe the status of field and geochronology studies of the Lathrop Wells center. Our perspective is that it is critical to assess all possible methods for obtaining cross-checking data to resolve chronology and field problems. It is equally important to consider application of the range of chronology methods available in Quaternary geologic research. Such an approach seeks to increase the confidence in data interpretations through obtaining convergence among separate isotopic, radiogenic, and age-correlated methods. Finally, the assumptions, strengths, and weaknesses of each dating method need to be carefully described to facilitate an impartial evaluation of results.

  18. The Lathrop Wells volcanic center: Status of field and geochronology studies

    International Nuclear Information System (INIS)

    Crowe, B.; Morley, R.; Wells, S.; Geissman, J.; McDonald, E.; McFadden, L.; Perry, F.; Murrell, M.; Poths, J.; Forman, S.

    1993-01-01

    The Lathrop Wells volcanic center is located 20 km south of the potential Yucca Mountain site, at the south end of the Yucca Mountain range. It has long been recognized as the youngest basalt center in the region. However, determination of the age and eruptive history of the center has proven problematic. The purpose of this paper is to describe the status of field and geochronology studies of the Lathrop Wells center. Our perspective is that it is critical to assess all possible methods for obtaining cross-checking data to resolve chronology and field problems. It is equally important to consider application of the range of chronology methods available in Quaternary geologic research. Such an approach seeks to increase the confidence in data interpretations through obtaining convergence among separate isotopic, radiogenic, and age-correlated methods. Finally, the assumptions, strengths, and weaknesses of each dating method need to be carefully described to facilitate an impartial evaluation of results

  19. Specialization in plant-hummingbird networks is associated with species richness, contemporary precipitation and quaternary climate-change velocity.

    Science.gov (United States)

    Dalsgaard, Bo; Magård, Else; Fjeldså, Jon; Martín González, Ana M; Rahbek, Carsten; Olesen, Jens M; Ollerton, Jeff; Alarcón, Ruben; Cardoso Araujo, Andrea; Cotton, Peter A; Lara, Carlos; Machado, Caio Graco; Sazima, Ivan; Sazima, Marlies; Timmermann, Allan; Watts, Stella; Sandel, Brody; Sutherland, William J; Svenning, Jens-Christian

    2011-01-01

    Large-scale geographical patterns of biotic specialization and the underlying drivers are poorly understood, but it is widely believed that climate plays an important role in determining specialization. As climate-driven range dynamics should diminish local adaptations and favor generalization, one hypothesis is that contemporary biotic specialization is determined by the degree of past climatic instability, primarily Quaternary climate-change velocity. Other prominent hypotheses predict that either contemporary climate or species richness affect biotic specialization. To gain insight into geographical patterns of contemporary biotic specialization and its drivers, we use network analysis to determine the degree of specialization in plant-hummingbird mutualistic networks sampled at 31 localities, spanning a wide range of climate regimes across the Americas. We found greater biotic specialization at lower latitudes, with latitude explaining 20-22% of the spatial variation in plant-hummingbird specialization. Potential drivers of specialization--contemporary climate, Quaternary climate-change velocity, and species richness--had superior explanatory power, together explaining 53-64% of the variation in specialization. Notably, our data provides empirical evidence for the hypothesized roles of species richness, contemporary precipitation and Quaternary climate-change velocity as key predictors of biotic specialization, whereas contemporary temperature and seasonality seem unimportant in determining specialization. These results suggest that both ecological and evolutionary processes at Quaternary time scales can be important in driving large-scale geographical patterns of contemporary biotic specialization, at least for co-evolved systems such as plant-hummingbird networks.

  20. Tectonic and climatic controls on late quaternary sedimentary processes in a neotectonic intramontane basin, the Pitalito Basin, South Colombia

    NARCIS (Netherlands)

    Bakker, J.

    1990-01-01

    The present study deals with the influence of tectonics and climatic changes on sedimentation patterns in the Quaternary Pitalito Basin (lat. 1°52'N, long. 76°02'W). This intramontane sedimentary basin is 15 km in width and 20 kin in length and is located in the Eastern Cordillera of the

  1. separation of strontium and cesium from ternary and quaternary lithium chloride-potassium chloride salts via melt crystallization

    Directory of Open Access Journals (Sweden)

    Ammon N. Williams

    2015-12-01

    Full Text Available Separation of cesium chloride (CsCl and strontium chloride (SrCl2 from the lithium chloride-potassium chloride (LiCl-KCl salt was studied using a melt crystallization process similar to the reverse vertical Bridgeman growth technique. A ternary SrCl2-LiCl-KCl salt was explored at similar growth rates (1.8–5 mm/h and compared with CsCl ternary results to identify similarities. Quaternary experiments were also conducted and compared with the ternary cases to identify trends and possible limitations to the separations process. In the ternary case, as much as 68% of the total salt could be recycled per batch process. In the quaternary experiments, separation of Cs and Sr was nearly identical at the slower rates; however, as the growth rate increased, SrCl2 separated more easily than CsCl. The quaternary results show less separation and rate dependence than in both ternary cases. As an estimated result, only 51% of the total salt could be recycled per batch. Furthermore, two models have been explored to further understand the growth process and separation. A comparison of the experimental and modeling results reveals that the nonmixed model fits reasonably well with the ternary and quaternary data sets. A dimensional analysis was performed and a correlation was identified to semipredict the segregation coefficient.

  2. Synthesis of Quaternary Ammonium Salts of Tricyclic Cationic Drugs: A One-Pot Synthesis for the Bioorganic Chemistry Laboratory

    Science.gov (United States)

    Brunauer, Linda S.; Mogannam, Abid C.; Hwee, Won B.; Chen, James Y.

    2007-01-01

    A one-pot conversion of tricyclic cationic drugs to their quaternary ammonium forms is described for a widely used bioactive drug: chlorpromazine, a phenothiazine-based antipsychotic. After conversion to its free base, the parent drug was methylated using substoichiometric amounts of methyl iodide dissolved in ether; the charged quaternary…

  3. Isothermal Vapor-Liquid Equilibrium in the Quaternary Water + 2-Propanol + Acetic Acid + Isopropyl Acetate System with Chemical Reaction

    Czech Academy of Sciences Publication Activity Database

    Teodorescu, M.; Aim, Karel; Wichterle, Ivan

    2001-01-01

    Roč. 46, č. 2 (2001), s. 261-266 ISSN 0021-9568 R&D Projects: GA ČR GA203/98/1446 Institutional research plan: CEZ:AV0Z4072921 Keywords : vapor-liquid equilibrium * quaternary water Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.960, year: 2001

  4. Microstructural aspects of manganese metal during its electrodeposition from sulphate solutions in the presence of quaternary amines

    Energy Technology Data Exchange (ETDEWEB)

    Padhy, Subrat Kumar [CSIR – Institute of Minerals and Materials Technology, Council of Scientific and Industrial Research, Bhubaneswar 751013 (India); Academy of Scientific and Innovative Research, CSIR Campus, CSIR Road, Taramani, Chennai 600 113 (India); Patnaik, P. [CSIR – Institute of Minerals and Materials Technology, Council of Scientific and Industrial Research, Bhubaneswar 751013 (India); Tripathy, B.C., E-mail: bankim@immt.res.in [CSIR – Institute of Minerals and Materials Technology, Council of Scientific and Industrial Research, Bhubaneswar 751013 (India); Academy of Scientific and Innovative Research, CSIR Campus, CSIR Road, Taramani, Chennai 600 113 (India); Bhattacharya, I.N. [CSIR – Institute of Minerals and Materials Technology, Council of Scientific and Industrial Research, Bhubaneswar 751013 (India)

    2015-03-15

    Graphical abstract: - Highlights: • Quaternary amines produced smooth and bright manganese electrodeposits. • TEABr produced smooth and bright deposits with euhedral shaped crystals. • TBABr produced dendritic deposits with elongated poly-nodular crystals. • All the quaternary amines behaved as cathode polarisers. • TEABr was found to be the most efficient organic additive. - Abstract: In the present study investigation was made on the electrodeposition of manganese from sulphate solutions in the presence of quaternary amines TEABr, TPABr and TBABr. The concentrations of these additives were varied over a relatively broad range to evaluate their effect on the deposit morphology and preferred crystal orientations of the electrodeposited metal. TEABr resulted in bright and smooth manganese electrodeposits giving euhedral shape to the crystals with distinct triple junction points. TPABr also showed similar results at lower concentrations. However, TBABr resulted in the formation of dendritic growths with elongated poly-nodular crystals similar to that of Paragorgia corals having uniform multistep growths. The presence of these quaternary amines in the electrolyte causes polarisation of the cathode. TBABr being the strongest cathode polariser adsorbs strongly on the cathode resulting in poor deposit quality. TEABr was found to be the most efficient additive producing the desired quality manganese electrodeposit.

  5. Thermodynamic modeling of ternary and quaternary (liquid + liquid) systems containing water, FeCl3, HCl and diisopropyl ether

    NARCIS (Netherlands)

    Milosevic, M.; Hendriks, I.; Smits, R.E.R.; Schuur, Boelo; de Haan, A.B.

    2013-01-01

    Liquid–liquid extraction using ethers as solvents is a potentially energy saving alternative for the concentration of aqueous ferric chloride solutions. Adequate thermodynamic models that describe the behavior of the resulting quaternary systems (FeCl3, ether, acid and water) are not available in

  6. The impact of the Quaternary glaciations on the Durmitor mountains (Montenegro) as understood from detailed geomorphological mapping

    Science.gov (United States)

    Frankl, Amaury; Annys, Klaas; Spalević, Velibor; Čurović, Milic; Borota, Dragan; Nyssen, Jan

    2014-05-01

    In the Balkans, few studies exist that highlight the impact of the Quaternary glaciations on the landscape. However, the impact of the Quaternary glaciations was important and the glacial imprint remains well preserved in the limestone massifs where karst hydrology prevails. This study presents a detailed geomorphological map at scale 1:10,000 that was prepared of the northeastern Durmitor mountains (2523 m a.s.l.) and the plateau Jezerska Površ (47 km², Dinaric Alps, Montenegro). Mapping occurred from an intensive fieldwork campaign and remote sensing analysis, and was finalized in a GIS environment. The basic components of the legend are (i) processes/genesis, (ii) materials, (iii) morphometry/morphography, (iv) hydrography, (v) vegetation and (vi) anthropogenic features, that are organized as a box-of-bricks type of legend (AGRG-system). The geomorphological setting of the area consists of Mesozoic limestones which were eroded physically by Quaternary glacial and periglacial activity and chemically during interglacials. Glacial deposits of three Middle to Late Pleistocene glacial phases exist on the plateau, only scarcely dissected by meltwater channels. In the mountains, Holocene glacier retreat left behind a series of well-preserved recessional moraines and a static glacier remains in the cirque head. The presented map serves as a valuable tool for Quaternary research in the Durmitor Mountains, and serves as an example on the interaction between glacial and karst processes. Keywords: Debeli Namet glacier, Dinaric Alps, Geographic Information System (GIS), Glacial landforms, Karst.

  7. Non-linear response of the Golo River system, Corsica, France, to Late Quaternary climatic and sea level variations

    NARCIS (Netherlands)

    Forzoni, A.; Storms, J.E.A.; Reimann, T.; Moreau, J.; Jouet, G.

    2015-01-01

    Disentangling the impact of climatic and sea level variations on fluvio-deltaic stratigraphy is still an outstanding question in sedimentary geology and geomorphology. We used the Golo River system, Corsica, France, as a natural laboratory to investigate the impact of Late Quaternary climate and sea

  8. Severnaya Zemlya, Arctic Russia: a nucleation area for Kara Sea ice sheets during the Middle to Late Quaternary

    NARCIS (Netherlands)

    Moller, P.; Lubinski, D.J.; Ingolfsson, O.; Forman, S.L.; Seidenkrantz, M.S.; Bolshiyanov, D.Y.; Lokrantz, H.; Antonov, O.; Pavlov, M.; Ljung, K.; Zeeberg, J.J.; Andreev, A.

    2006-01-01

    Quaternary glacial stratigraphy and relative sea-level changes reveal at least four expansions of the Kara Sea ice sheet over the Severnaya Zemlya Archipelago at 79°N in the Russian Arctic, as indicated from tills interbedded with marine sediments, exposed in stratigraphic superposition, and from

  9. Specialization in plant-hummingbird networks is associated with species richness, contemporary precipitation and quaternary climate-change velocity.

    Directory of Open Access Journals (Sweden)

    Bo Dalsgaard

    Full Text Available Large-scale geographical patterns of biotic specialization and the underlying drivers are poorly understood, but it is widely believed that climate plays an important role in determining specialization. As climate-driven range dynamics should diminish local adaptations and favor generalization, one hypothesis is that contemporary biotic specialization is determined by the degree of past climatic instability, primarily Quaternary climate-change velocity. Other prominent hypotheses predict that either contemporary climate or species richness affect biotic specialization. To gain insight into geographical patterns of contemporary biotic specialization and its drivers, we use network analysis to determine the degree of specialization in plant-hummingbird mutualistic networks sampled at 31 localities, spanning a wide range of climate regimes across the Americas. We found greater biotic specialization at lower latitudes, with latitude explaining 20-22% of the spatial variation in plant-hummingbird specialization. Potential drivers of specialization--contemporary climate, Quaternary climate-change velocity, and species richness--had superior explanatory power, together explaining 53-64% of the variation in specialization. Notably, our data provides empirical evidence for the hypothesized roles of species richness, contemporary precipitation and Quaternary climate-change velocity as key predictors of biotic specialization, whereas contemporary temperature and seasonality seem unimportant in determining specialization. These results suggest that both ecological and evolutionary processes at Quaternary time scales can be important in driving large-scale geographical patterns of contemporary biotic specialization, at least for co-evolved systems such as plant-hummingbird networks.

  10. Poly(amido amine)s as gene delivery vectors: effects of quaternary nicotinamide moieties in the side chains

    NARCIS (Netherlands)

    Mateos timoneda, Miguel; Lok, Martin C.; Hennink, Wim E.; Feijen, Jan; Engbersen, Johannes F.J.

    2008-01-01

    To evaluate the effect of quaternary nicotinamide pendant groups on gene delivery properties, a series of poly(amido amine) (co)polymers were synthesized by Michael addition polymerization of N, N-cystaminebisacrylamide with variable ratios of 1-(4-aminobutyl)-3-carbamoylpyridinium (Nic-BuNH2), and

  11. Survival of adhering staphylococci during exposure to a quaternary ammonium compound evaluated by using atomic force microscopy imaging

    NARCIS (Netherlands)

    Crismaru, Mihaela; Asri, Lia ATW; Loontjens, Jacobus; Krom, Bastiaan P; de Vries, Jacob; van der Mei, Henderina; Busscher, Hendrik

    2011-01-01

    Effects of a quaternary ammonium compound (QAC) on the survival of adhering staphylococci on a surface were investigated using atomic force microscopy (AFM). Four strains with different minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) for the QAC were exposed to

  12. Medical overuse and quaternary prevention in primary care - A qualitative study with general practitioners.

    Science.gov (United States)

    Alber, Kathrin; Kuehlein, Thomas; Schedlbauer, Angela; Schaffer, Susann

    2017-12-08

    Medical overuse is a topic of growing interest in health care systems and especially in primary care. It comprises both over investigation and overtreatment. Quaternary prevention strategies aim at protecting patients from unnecessary or harmful medicine. The objective of this study was to gain a deeper understanding of relevant aspects of medical overuse in primary care from the perspective of German general practitioners (GPs). We focused on the scope, consequences and drivers of medical overuse and strategies to reduce it (=quaternary prevention). We used the qualitative Grounded Theory approach. Theoretical sampling was carried out to recruit GPs in Bavaria, Germany. We accessed the field of research through GPs with academic affiliation, recommendations by interview partners and personal contacts. They differed in terms of primary care experience, gender, region, work experience abroad, academic affiliation, type of specialist training, practice organisation and position. Qualitative in-depth face-to-face interviews with a semi-structured interview guide were conducted (n = 13). The interviews were audiotaped and transcribed verbatim. Data analysis was carried out using open and axial coding. GPs defined medical overuse as unnecessary investigations and treatment that lack patient benefit or bear the potential to cause harm. They observed that medical overuse takes place in all three German reimbursement categories: statutory health insurance, private insurance and individual health services (direct payment). GPs criticised the poor acceptance of gate-keeping in German primary care. They referred to a low-threshold referral policy and direct patient access to outpatient secondary care, leading to specialist treatment without clear medical indication. The GPs described various direct drivers of medical overuse within their direct area of influence. They also emphasised indirect drivers related to system or societal processes. The proposed strategies for

  13. A paleoenvironmental study of subsurface Quaternary sediments at Wainuiomata, Wellington, New Zealand, and tectonic implications

    International Nuclear Information System (INIS)

    Begg, J.G.; Mildenhall, D.C.; Lyon, G.L.; Stephenson, W.R.; Funnell, R.H.; Van Dissen, R.J.; Bannister, S.; Brown, L.J.; Pillans, B.; Harper, M.A.; Whitton, J.

    1993-01-01

    A stratigraphic drillhole (WS-1) sited on the floor of Wainuiomata Valley near Lower Hutt, revealed a 61.6 m thick Quaternary sequence overlying Torlesse Supergroup greywacke sandstone and argillite. The Quaternary sediments consist of three sequences separated by disconformities. The lower sequence, 10.7 m thick (61.6-50.9 m), consists of fluvial sediments of probable early Quaternary age. The middle sequence, about 48.3 m in thickness (50.9-c. 2.6 m), spans most of the Last Glaciation. Fluvial/overbnak (50.9-42.0 m), floodplain/swamp (42.9-34.5 m), and fluvial (34.5-31.3 m) sediments overlie the disconformity at 50.9 m. Conformably overlying these sediments are swamp and lacustrine deposits between 31.3 and 4.1 m. Diatoms and algal spores and coenobia show the existence of an extensive lake during much of this sequence, from 25.6 to 4.0 m. at the peak of its development, at a drillhole depth of c. 23 m, the lake was >10 m deep and had a high algal biomass. Kawakawa Tephra (22 600 yr b.p.) occurs near the top of the middle sequence at 4.1 m depth. The upper sequence, of Holocene-Recent age, is <2.6 m thick, including .06 m of fill. The existence of sediments of the lower sequence of at least Castlecliffian age (early Pleistocene) uncomformably overlying basement greywacke provides a minimum age for the K-surface in the area. The Last Glacial sediments show evidence of ponfing, which may be a result of one factor or a combination of the following: ponding behind an aggradational terrace of the Wainuiomata River; landslide blockage of the Black Stream drainage near its confluence with Wainuiomata River; and tectonic deformation. Progressive tectonic deformation since about the start of the Last Glaciation is considered the most likely dominant factor. This has resulted in the elevation of greywacke basement near the junction of Black Stream and Wainuiomata River. The nature of the deformation - faulting, tilting, and/or folding - has not been established. (authors

  14. C18-COOH Silica: Preparation, Characterisation and Its Application in Purification of Quaternary Ammonium Alkaloids from Coptis chinensis.

    Science.gov (United States)

    Wang, Qing; Long, Yao; Yao, Lin; Ye, Mao; Xu, Li

    2017-07-01

    Traditional methods for isolating and purifying quaternary ammonium alkaloids from Coptis chinensis do not discriminate the target alkaloids from co-extractives. Mixed-mode analytical chromatography has the potential to improve the separation of analytes in more complex extracts and, when used in a solid-phase extraction mode, improve the purity of isolated compounds. To examine the high-performance liquid chromatographic separation capabilities of a mixed-mode, silica-based adsorbent and its application to the purification of quaternary ammonium alkaloids from Coptis chinensis based on solid-phase extraction. The C18-COOH silica was prepared via "thiol-ene" click chemistry. Its chromatographic performance was firstly investigated. It was employed as the solid-phase extraction sorbent to purify quaternary ammonium alkaloids. Hydrophobic, attractive/repulsive electrostatic and ion-exchange interactions were demonstrated to be the possible retention mechanisms of a C18-COOH silica stationary phase, which could separate analytes of various properties. In addition, to purify quaternary ammonium alkaloids from Coptis chinensis, the solid-phase extraction approach based on the C18-COOH silica provided a slightly higher purification efficiency (6.7%) than an alkaloid-salt precipitation protocol (5.3%). The method had satisfactory reproducibility, re-using the same solid-phase extraction column three times, with relative standard deviations ranging from 1.99% to 8.02% for the six target alkaloids. A multi-functionalised silica was synthesised via "click chemistry". As the high-performance liquid chromatographic stationary phase, the C18-COOH silica could be operated in trimodal reversed-phase/weak cation exchange/hydrophilic interaction mode. The C18-COOH silica also exhibited potential as solid-phase extraction sorbent in the purification of quaternary ammonium alkaloids from complex matrices. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons

  15. Evaluating the significance of paleophylogeographic species distribution models in reconstructing quaternary range-shifts of nearctic chelonians.

    Directory of Open Access Journals (Sweden)

    Dennis Rödder

    Full Text Available The climatic cycles of the Quaternary, during which global mean annual temperatures have regularly changed by 5-10°C, provide a special opportunity for studying the rate, magnitude, and effects of geographic responses to changing climates. During the Quaternary, high- and mid-latitude species were extirpated from regions that were covered by ice or otherwise became unsuitable, persisting in refugial retreats where the environment was compatible with their tolerances. In this study we combine modern geographic range data, phylogeny, Pleistocene paleoclimatic models, and isotopic records of changes in global mean annual temperature, to produce a temporally continuous model of geographic changes in potential habitat for 59 species of North American turtles over the past 320 Ka (three full glacial-interglacial cycles. These paleophylogeographic models indicate the areas where past climates were compatible with the modern ranges of the species and serve as hypotheses for how their geographic ranges would have changed in response to Quaternary climate cycles. We test these hypotheses against physiological, genetic, taxonomic and fossil evidence, and we then use them to measure the effects of Quaternary climate cycles on species distributions. Patterns of range expansion, contraction, and fragmentation in the models are strongly congruent with (i phylogeographic differentiation; (ii morphological variation; (iii physiological tolerances; and (iv intraspecific genetic variability. Modern species with significant interspecific differentiation have geographic ranges that strongly fluctuated and repeatedly fragmented throughout the Quaternary. Modern species with low genetic diversity have geographic distributions that were highly variable and at times exceedingly small in the past. Our results reveal the potential for paleophylogeographic models to (i reconstruct past geographic range modifications, (ii identify geographic processes that result in

  16. 13C NMR and XPS characterization of anion adsorbent with quaternary ammonium groups prepared from rice straw, corn stalk and sugarcane bagasse

    Science.gov (United States)

    Cao, Wei; Wang, Zhenqian; Zeng, Qingling; Shen, Chunhua

    2016-12-01

    Despite amino groups modified crop straw has been intensively studied as new and low-cost adsorbent for removal of anionic species from water, there is still a lack of clear characterization for amino groups, especially quaternary ammonium groups in the surface of crop straw. In this study, we used 13C NMR and XPS technologies to characterize adsorbents with quaternary ammonium groups prepared from rice straw, corn stalk and sugarcane bagasse. 13C NMR spectra clearly showed the presence of quaternary ammonium groups in lignocelluloses structure of modified crop straw. The increase of nitrogen observed in XPS survey spectra also indicated the existence of quaternary ammonium group in the surface of the adsorbents. The curve fitting of high-resolution XPS N1s and C1s spectra were conducted to probe the composition of nitrogen and carbon contained groups, respectively. The results showed the proportion of quaternary ammonium group significantly increased in the prepared adsorbent's surface that was dominated by methyl/methylene, hydroxyl, quaternary ammonium, ether and carbonyl groups. This study proved that 13C NMR and XPS could be successfully utilized for characterization of quaternary ammonium modified crop straw adsorbents.

  17. Quaternary ammonium oxidative demethylation: X-ray crystallographic, resonance Raman, and UV-visible spectroscopic analysis of a Rieske-type demethylase.

    Science.gov (United States)

    Daughtry, Kelly D; Xiao, Youli; Stoner-Ma, Deborah; Cho, Eunsun; Orville, Allen M; Liu, Pinghua; Allen, Karen N

    2012-02-08

    Herein, the structure resulting from in situ turnover in a chemically challenging quaternary ammonium oxidative demethylation reaction was captured via crystallographic analysis and analyzed via single-crystal spectroscopy. Crystal structures were determined for the Rieske-type monooxygenase, stachydrine demethylase, in the unliganded state (at 1.6 Å resolution) and in the product complex (at 2.2 Å resolution). The ligand complex was obtained from enzyme aerobically cocrystallized with the substrate stachydrine (N,N-dimethylproline). The ligand electron density in the complex was interpreted as proline, generated within the active site at 100 K by the absorption of X-ray photon energy and two consecutive demethylation cycles. The oxidation state of the Rieske iron-sulfur cluster was characterized by UV-visible spectroscopy throughout X-ray data collection in conjunction with resonance Raman spectra collected before and after diffraction data. Shifts in the absorption band wavelength and intensity as a function of absorbed X-ray dose demonstrated that the Rieske center was reduced by solvated electrons generated by X-ray photons; the kinetics of the reduction process differed dramatically for the liganded complex compared to unliganded demethylase, which may correspond to the observed turnover in the crystal.

  18. Sr, Nd and Pb isotope and geochemical data from the Quaternary Nevado de Toluca volcano, a source of recent adakitic magmatism, and the Tenango Volcanic Field, Mexico

    Science.gov (United States)

    Martínez-Serrano, Raymundo G.; Schaaf, Peter; Solís-Pichardo, Gabriela; Hernández-Bernal, Ma. del Sol; Hernández-Treviño, Teodoro; Julio Morales-Contreras, Juan; Macías, José Luis

    2004-11-01

    Volcanic activity at Nevado de Toluca (NT) volcano began 2.6 Ma ago with the emission of andesitic lavas, but over the past 40 ka, eruptions have produced mainly lava flows and pyroclastic deposits of predominantly orthopyroxene-hornblende dacitic composition. In the nearby Tenango Volcanic Field (TVF) pyroclastic products and lava flows ranging in composition from basaltic andesite to andesite were erupted at most of 40 monogenetic volcanic centers and were coeval with the last stages of NT. All volcanic rocks in the study area are characterized by a calc-alkaline affinity that is consistent with a subduction setting. Relatively high concentrations of Sr (>460 ppm) coupled with low Y (45 km) that underlies the volcanoes of the study area, the geochemical and isotopic patterns of these rocks indicate low interaction with this crust. NT volcano was constructed at the intersection of three fault systems, and it seems that the Plio-Quaternary E-W system played an important role in the ascent and storage of magmas during the recent volcanic activity in the two regions. Chemical and textural features of orthopyroxene, amphibole and Fe-Ti oxides from NT suggest that crystallization of magmas occurred at polybaric conditions, confirming the rapid upwelling of magmas.

  19. Synthesis and evaluation of ageing effect on Cu–Al–Be–Mn quaternary Shape Memory Alloys

    Directory of Open Access Journals (Sweden)

    A.G. Shivasiddaramiah

    2016-09-01

    Full Text Available Copper based shape memory alloy exhibits high transformation temperature and ability to differ the achieved properties through alloying additions. A quaternary Cu–Al–Be–Mn shape memory alloys of 0.2–0.4 wt% of manganese, 0.4–0.5 wt% of Beryllium and 10–14 wt% of aluminium with remaining copper, showing β-phase at higher temperature and show shape memory effect when quenching to lower temperatures, SMA's were prepared by induction melting. The objective is to study the effect of thermal ageing at different temperatures Af (above austenitic phase finish temperature and at different time on shape memory effect and transformation temperatures. The aged specimens or SMA's were studied by DSC, OM and hardness measurements. The results from this study help to find the applications in different thermal conditions.

  20. Species-specific responses of Late Quaternary megafauna to climate and humans

    DEFF Research Database (Denmark)

    Lorenzen, Eline D; Nogués-Bravo, David; Orlando, Ludovic

    2011-01-01

    Despite decades of research, the roles of climate and humans in driving the dramatic extinctions of large-bodied mammals during the Late Quaternary period remain contentious. Here we use ancient DNA, species distribution models and the human fossil record to elucidate how climate and humans shaped...... the demographic history of woolly rhinoceros, woolly mammoth, wild horse, reindeer, bison and musk ox. We show that climate has been a major driver of population change over the past 50,000 years. However, each species responds differently to the effects of climatic shifts, habitat redistribution and human...... encroachment. Although climate change alone can explain the extinction of some species, such as Eurasian musk ox and woolly rhinoceros, a combination of climatic and anthropogenic effects appears to be responsible for the extinction of others, including Eurasian steppe bison and wild horse. We find no genetic...

  1. Global late Quaternary megafauna extinctions linked to humans, not climate change

    DEFF Research Database (Denmark)

    Sandom, Christopher James; Faurby, Søren; Sandel, Brody Steven

    2014-01-01

    The late Quaternary megafauna extinction was a severe global-scale event. Two factors, climate change and modern humans, have received broad support as the primary drivers, but their absolute and relative importance remains controversial. To date, focus has been on the extinction chronology...... of individual or small groups of species, specific geographical regions or macroscale studies at very coarse geographical and taxonomic resolution, limiting the possibility of adequately testing the proposed hypotheses. We present, to our knowledge, the first global analysis of this extinction based...... on comprehensive country-level data on the geographical distribution of all large mammal species (more than or equal to 10 kg) that have gone globally or continentally extinct between the beginning of the Last Interglacial at 132 000 years BP and the late Holocene 1000 years BP, testing the relative roles played...

  2. Crystal structure of the quaternary alloy CuTaInSe{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Mora, A.J. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Grima-Gallardo, P.; Duran, S.; Munoz, M.; Quintero, M. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Delgado, G.E.

    2008-07-15

    The crystal structure of the quaternary compound CuTaInSe{sub 3} belonging to the system (CuInSe{sub 2}){sub 1-x}(TaSe){sub x} with x=0.5, was analyzed using X-ray powder diffraction data. This material is isostructural with the CuFeInSe{sub 3} compound, and crystallize in the tetragonal space group P42c (N 112), Z=1, with unit cell parameters a=5.7831(1) A, c=11.6227(4) A, V=388.71(2) A{sup 3}. The Rietveld refinement of 18 instrumental and structural variables led to R{sub p}=8.0%, R{sub wp}=9.5%, R{sub exp}=6.3% and {chi}{sup 2}=1.5 for 4501 step intensities and 144 independent reflections. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Late Pliocene Quaternary tectonics in the frontal part of the SE Carpathians: Insights from tectonic geomorphology

    Science.gov (United States)

    Necea, Diana; Fielitz, W.; Matenco, L.

    2005-12-01

    The Romanian East Carpathians display large-scale heterogeneities along the mountain belt, unusual foredeep geometries, significant post-collisional and neotectonic activity, and major variations in topography, mostly developed in the aftermath of late Miocene (Sarmatian; ˜11 Ma) subduction/underthrusting and continental collision between the East European/Scythian/Moesian foreland and the inner Carpathians Tisza-Dacia unit. In particular, the SE corner of the arcuate orogenic belt represents the place of still active large-scale differential vertical movements between the uplifting mountain chain and the subsiding Focşani foredeep basin. In this key area, we have analysed the configuration of the present day landforms and the drainage patterns in order to quantify the amplitude, timing and kinematics of these post-collisional late Pliocene-Quaternary vertical movements. A river network is incising in the upstream a high topography consisting of the external Carpathians nappes and the Pliocene-Lower Pleistocene sediments of the foreland. Further eastwards in the downstream, this network is cross-cutting a low topography consisting of the Middle Pleistocene-Holocene sediments of the foreland. Geological observations and well-preserved geomorphic features demonstrate a complex succession of geological structures. The late Pliocene-Holocene tectonic evolution is generally characterised by coeval uplift in the mountain chain and subsidence in the foreland. At a more detailed scale, these vertical movements took place in pulses of accelerated motion, with laterally variable amplitude both in space and in time. After a first late Pliocene uplifting period, subsidence took place during the Earliest Pleistocene resulting in a basal Quaternary unconformity. This was followed by two, quantifiable periods of increased uplift, which affected the studied area at the transition between the Carpathians orogen and the Focşani foreland basin in the late Early Pleistocene and the

  4. Mapped plant macrofossil and pollen records of late Quaternary vegetation change in eastern North America

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, S.T.; Overpeck, J.T.; Webb, T. III [Northern Arizona Univ., Flagstaff, AZ (United States)]|[NOAA/NGDC, Boulder, CO (United States)]|[Brown Univ., Providence, RI (United States)

    1995-06-01

    We compiled a plant macrofossil database for 12 eastern North American tree and shrub taxa (Picea sp., P. glauca, P. mariana, Larix laricina, Abies balsamea, Tsuga canadensis, Pinus strobus, P. banksiana, P. resinosa, Betula papyrifera, B. alleghaniensis, B. Series Humiles) at 264 late Quaternary sites. Presence/absence maps for these taxa at 18,000, 15,000, 12,000, 9000, 6000, 3000, and 0 {sup 14}C yr B.P. show changes in geographic ranges of these species in response to climatic change. Comparison of the macrofossil maps with isopoll maps for corresponding taxa corroborates inferences from the pollen data, and reveals species-level patterns not apparent in the pollen maps.

  5. Application of DOI index to analysis of selected examples of resistivity imaging models in Quaternary sediments

    Directory of Open Access Journals (Sweden)

    Glazer Michał

    2014-12-01

    Full Text Available Interpretation of resistivity cross sections may be in many cases unreliable due to the presence of artifacts left by the inversion process. One way to avoid erroneous conclusions about geological structure is creation of Depth of Investigation (DOI index maps, which describe durability of prepared model with respect to variable parameters of inversion. To assess the usefulness of this interpretation methodology in resistivity imaging method over quaternary sediments, it has been used to one synthetic data set and three investigation sites. Two of the study areas were placed in the Upper Silesian Industrial District region: Bytom - Karb, Chorzów - Chorzow Stary; and one in the Southern Pomeranian Lake District across Piława River Valley. Basing on the available geological information the results show high utility of DOI index in analysis of received resistivity models, on which areas poorly constrained by data has been designated.

  6. Paleoenvironmental Reconstruction of Late Quaternary Insect Fossils, Halashazi Site, Altai Region, China.

    Science.gov (United States)

    Zhang, Tianshu; Elias, Scott; Angus, Robert

    2017-04-01

    The Altai region northwest China, is located in the middle of arid central Asia and is therefore sensitive to climate change. However, there is a debate on the heat-moisture pattern (warm-dry pattern or cold-dry pattern) during the early Holocene in the Altai region, and a debate on the dominant atmospheric circulation (westerlies or monsoon) control for central Asian climate changes during the Holocene, and the mechanisms that cause the arid early Holocene in central Asia. Thus, the principal aim of the project is use the MCR method to produce quantified temperature and precipitation estimates, and a high-precision palaeoclimatic record for the Altai region, based on fossil beetle assemblages, to reveal the heat-moisture pattern and its mechanisms. This project will begin to fill in the blank of Quaternary beetle research in China. Using Quaternary beetles to reconstruct palaeoenvironments is a new research method for this region, and has never before been done in China, which will provide new evidence for the palaeoenvironmental study in this area. Furthermore, this project will contribute to the beetle faunal research in Eurasia. The sample site for this project - Halashazi Wetland (048°06'54"N, 088°21'48"E), is located at the crossroad of the Altai Mountains and the Dzungarian Basin, where two ecosystems meet. Thus the fossil beetle assemblages should show dramatic change in response to changes of climate. The sampled deposits are made up entirely of sedge peat. Two different profiles were sampled, with depths of 160 cm and 200 cm, respectively. Both profiles were sampled at 5 cm intervals, with approximately 2 kg of material in each unit. The results of the radiocarbon dating will be available in December 2016. Based on other previous studies, the bottom of the peat sediment is 11,500 cal yr BP, so project focuses on the Holocene period approximately from 10,000 cal yr BP. More than 80 species of Coleoptera from 55 genera, 22 families have been recognised so

  7. Quaternary North Atlantic Surface Paleoceanography in Regions of Potential Deep-water Formation

    Science.gov (United States)

    Ruddiman, W. F.

    1984-01-01

    At the time scale of the Quaternary climate cycles, the sites of formation of North Atlantic Deep Water are not known. The interglacial extreme is presumably exemplified by the modern regions; the Norwegian, Greenland and Labrador Seas. During the major glacial-age coolings in the North Atlantic, the sites may have shifted well to the south, perhaps as far as the limit of the polar front at 40 to 50 N. Still other sites may have been important during intermediate climatic conditions. Because of the close coupling of high-latitude surface waters to North Atlantic Deep Water in the modern ocean, the history of sea-surface temperature (SST) oscillations across the high-latitude North Atlantic is relevant to an understanding of deep-water formation on the longer time scales.

  8. Maps of Quaternary Deposits and Liquefaction Susceptibility in the Central San Francisco Bay Region, California

    Science.gov (United States)

    Witter, Robert C.; Knudsen, Keith L.; Sowers, Janet M.; Wentworth, Carl M.; Koehler, Richard D.; Randolph, Carolyn E.; Brooks, Suzanna K.; Gans, Kathleen D.

    2006-01-01

    This report presents a map and database of Quaternary deposits and liquefaction susceptibility for the urban core of the San Francisco Bay region. It supercedes the equivalent area of U.S. Geological Survey Open-File Report 00-444 (Knudsen and others, 2000), which covers the larger 9-county San Francisco Bay region. The report consists of (1) a spatial database, (2) two small-scale colored maps (Quaternary deposits and liquefaction susceptibility), (3) a text describing the Quaternary map and liquefaction interpretation (part 3), and (4) a text introducing the report and describing the database (part 1). All parts of the report are digital; part 1 describes the database and digital files and how to obtain them by downloading across the internet. The nine counties surrounding San Francisco Bay straddle the San Andreas fault system, which exposes the region to serious earthquake hazard (Working Group on California Earthquake Probabilities, 1999). Much of the land adjacent to the Bay and the major rivers and streams is underlain by unconsolidated deposits that are particularly vulnerable to earthquake shaking and liquefaction of water-saturated granular sediment. This new map provides a consistent detailed treatment of the central part of the 9-county region in which much of the mapping of Open-File Report 00-444 was either at smaller (less detailed) scale or represented only preliminary revision of earlier work. Like Open-File Report 00-444, the current mapping uses geomorphic expression, pedogenic soils, inferred depositional environments, and geologic age to define and distinguish the map units. Further scrutiny of the factors controlling liquefaction susceptibility has led to some changes relative to Open-File Report 00-444: particularly the reclassification of San Francisco Bay mud (Qhbm) to have only MODERATE susceptibility and the rating of artificial fills according to the Quaternary map units inferred to underlie them (other than dams - adf). The two colored

  9. Differentiating clinical care from disease prevention: a prerequisite for practicing quaternary prevention

    Directory of Open Access Journals (Sweden)

    Charles Dalcanale Tesser

    Full Text Available Abstract: This article contends that the distinction between clinical care (illness and prevention of future disease is essential to the practice of quaternary prevention. The authors argue that the ongoing entanglement of clinical care and prevention transforms healthy into "sick" people through changes in disease classification criteria and/or cut-off points for defining high-risk states. This diverts health care resources away from those in need of care and increases the risk of iatrogenic harm in healthy people. The distinction in focus is based on: (a management of uncertainty (more flexible when caring for ill persons; (b guarantee of benefit (required only in prevention; (c harm tolerance (nil or minimal in prevention. This implies attitudinal differences in the decision-making process: greater skepticism, scientism and resistance towards preventive action. These should be based on high-quality scientific evidence of end-outcomes that displays a net positive harm/benefit ratio.

  10. Quaternary sediment thickness and bedrock topography of the glaciated United States east of the Rocky Mountains

    Science.gov (United States)

    Soller, David R.; Garrity, Christopher P.

    2018-01-26

    is called the Holocene and, together with the Pleistocene, constitutes the Quaternary Period of geologic time; this publication characterizes the three-dimensional geometry of the Quaternary sediments and the bedrock surface that lies beneath.The pre-glacial landscape was underlain mostly by weathered bedrock generally similar in nature to that found in many areas of the non-glaciated United States. Glacial erosion and redeposition of earth materials produced a young, mineral-rich soil that formed the basis for the highly productive agricultural economy in the U.S. midcontinent. Extensive buried sands and gravels within the glacial deposits also provided a stimulus to other economic sectors by serving as high-quality aquifers supplying groundwater to the region’s industry and cities. An understanding of the three-dimensional distribution of these glacial sediments has direct utility for addressing various societal issues including groundwater quality and supply, and landscape and soil response to earthquake-induced shaking.The Quaternary sediment thickness map and bedrock topographic map shown here provide a regional overview and are intended to supplement the more detailed work on which they are based. Detailed mapping is particularly useful in populated areas for site-specific planning. In contrast, regional maps such as these serve to place local, detailed mapping in context; to permit the extrapolation of data into unmapped areas; and to depict large-scale regional geologic features and patterns that are beyond the scope of local, detailed mapping. They also can enhance the reader’s general understanding of the region’s landscape and geologic history and provide a source of information for regional decision making that could benefit by improved predictability of bedrock depth beneath the unconsolidated Quaternary sediments. To enable these maps to be analyzed in conjunction with other types of information, this publication also includes the map data in GIS

  11. The smallest quaternary ammonium salts with ether groups for high-performance electrochemical double layer capacitors.

    Science.gov (United States)

    Han, Taihee; Park, Min-Sik; Kim, Jeonghun; Kim, Jung Ho; Kim, Ketack

    2016-03-01

    Electrochemical double layer capacitors (EDLCs) are energy storage devices that have been used for a wide range of electronic applications. In particular, the electrolyte is one of the important components, directly related to the capacitance and stability. Herein, we first report a series of the smallest quaternary ammonium salts (QASs), with ether groups on tails and tetrafluoroborate (BF 4 ) as an anion, for use in EDLCs. To find the optimal structure, various QASs with different sized head groups and ether-containing tail groups were systematically compared. Comparing two nearly identical structures with and without ether groups, QASs with oxygen atoms showed improved capacitance, proving that ions with oxygen atoms move more easily than their counterparts at lower electric fields. Moreover, the ether containing QASs showed low activation energy values of conductivities, leading to smaller IR drops during the charge and discharge processes, resulting in an overall higher capacitance.

  12. Structure and activity of thermophilic methanogenic microbial communities exposed to quaternary ammonium sanitizer.

    Science.gov (United States)

    Fernandez-Bayo, Jesus D; Toniato, Juliano; Simmons, Blake A; Simmons, Christopher W

    2017-06-01

    Food processing facilities often use antimicrobial quaternary ammonium compound (QAC) sanitizers to maintain cleanliness. These QACs can end up in wastewaters used as feedstock for anaerobic digestion. The aim of this study was to measure the effect of QAC contamination on biogas production and structure of microbial communities in thermophilic digester sludge. Methane production and biogas quality data were analyzed in batch anaerobic digesters containing QAC at 0, 15, 50, 100 and 150mg/L. Increasing sanitizer concentration in the bioreactors negatively impacted methane production rate and biogas quality. Microbial community composition data was obtained through 16S rRNA gene sequencing from the QAC-contaminated sludges. Sequencing data showed no significant restructuring of the bacterial communities. However, significant restructuring was observed within the archaeal communities as QAC concentration increased. Further studies to confirm these effects on a larger scale and with a longer retention time are necessary. Copyright © 2016. Published by Elsevier B.V.

  13. Gravity field separation and mapping of buried quaternary valleys in Lolland, Denmark using old geophysical data

    DEFF Research Database (Denmark)

    Møller, M.J.; Olsen, Henrik; Ploug, C.

    2007-01-01

    In this paper we utilise the old industrial data for planning new surveys. The overall purpose is a detailed mapping of possible aquifers for the island of Lolland, Denmark. This is done through detection and modelling of the buried quaternary valleys, which either can serve as potential aquifers...... or potential aquifer barriers. The present paper deals only with one aspect of a larger study; namely a case story leading to the detection of unknown buried valleys and the first attempts to model them in 3D from gravity and seismics. Also, the emphasis here is not on any theoretical or even methodological...... the results): the construction of depth models from industrial seismic data for known geological units; geological stripping with mass density adjustment; high-pass filtering of the residual gravity signals; vibroseis surveys; microgravity surveys along seismic lines; the first modelling of buried valleys....

  14. Principles and reconstruction of the ancient sea levels during the Quaternary

    International Nuclear Information System (INIS)

    Martin, L.; Flexor, J.M.; Suguio, K.

    1986-01-01

    This work focused the multiple aspects related to the ''reconstruction of the ancient sea level during the Quaternary''. The relative sea level, fluctuations are produced by true variations of the level (eustasy) and by changes in the land level (tectonism and isostasy). The changes of the relative levels are reconstructed through several evidence of these fluctuations, which are recognised in time and space. To define their situation in space is necessary to know their present altitude in relation to their original altitude, that is, to determine their position in relation to the sea level during their formation or sedimentation. Their situation in time is determined by measuring the moment of their formation or sedimentation, using for this the dating methods (isotopic, archeological, etc.) When numerous ancient levels could be reconstructed, spread through a considerable time interval, is possible to delineate the sea level fluctuation curve for this period. (C.D.G.) [pt

  15. Quaternary ammonium based task specific ionic liquid for the efficient and selective extraction of neptunium

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Nishesh Kumar [National Institute of Technology, Odisha (India). Dept. of Chemistry; Sengupta, Arijit [Bhabha Atomic Research Centre, Mumbai (India). Radiochemistry Div.; Biswas, Sujoy [Bhabha Atomic Research Centre, Mumbai (India). Uranium Extraction Div.

    2017-07-01

    Liquid-liquid extraction of neptunium from aqueous acidic solution using quaternary ammonium based task specific ionic liquid (TSIL) was investigated. The extraction of Np was predominated by the 'cation exchange' mechanism via [NpO{sub 2}.Hpth]{sup +} species for NpO{sub 2}{sup 2+}, while NpO{sub 2}{sup +} was extracted in ionic liquid as [NpO{sub 2}.H.Hpth]{sup +}. The extraction process was thermodynamically spontaneous while kinetically slower. Na{sub 2}CO{sub 3} as strippant showed quantitative back extraction of neptunium ions from TSIL. TSIL showed excellent radiolytic stability upto 500 kGy gamma exposure. Finally, the TSIL was employed for the processing of simulated high level waste solutions revealing high selectivity of TSIL towards neptunium.

  16. Pe do sedimentary sequence in late Quaternary section in Zarate, Argentina

    International Nuclear Information System (INIS)

    Tofalo, O.; Orgeira, M.; Alonso, M.; Ramos, A.

    2007-01-01

    Field geological features, grain-size, sand, silt and clay mineralogy, micromorphology, optically simulated luminiscence (OSL) ages have been used to reconstruct the pedosedimentary sequence in a late Quaternary section in Zarate, Buenos Aires province. Paleosols were developed on loess and four clear discontinuities in sedimentation and paleosols generation were observed. These discontinuities have determinated four units with different types of calcrete. The welded paleosols developed on unit C can be 1correlated and linked to the other ones outcropped in Baradero (Buenos Aires province) and Lozada (Cordoba province). These records probably span the equivalent of marine oxygen isotope stage (OIS) 5, the last interglacial stage before the present. The ground water and pedogenic calcretes and their association with smectite, illite and ferric oxide suggest dried climate than present one and strongly seasonality. (author)

  17. Quaternary molluscan faunas from the island of Tierra del Fuego after the Last Glacial Maximum

    Directory of Open Access Journals (Sweden)

    Sandra Gordillo

    2005-12-01

    Full Text Available Palaeontological studies on postglacial molluscan faunas from marine deposits located along the northern coast of the Beagle Channel (lat. 54°55’S, long. 68°34’-67°11’W showed differences of various molluscan assemblages during a period of climatic stability after deglaciation. Oceanographic changes, different local environmental conditions and/or episodes of minor climatic fluctuations are pointed out as causes for the variations in faunal composition. Comparison with Quaternary molluscs from Antarctica showed that these palaeofaunas overlap slightly at the species level, but have a considerable number of genera (23% and families (50% in common. These affinities and relationships are better explained on the basis of more recent migrating taxa than by ancient connections when the two regions formed part of the Weddellian Province.

  18. Evaluation of the behavior of Brazilian bentonite clays with different quantity of quaternary ammonium salt

    International Nuclear Information System (INIS)

    Barbosa, Renata; Souza, Dayanne Diniz; Araujo, Edcleide Maria; Nobrega, Karine Castro; Melo, Tomas Jeferson Alves

    2009-01-01

    Paraiba is the main natural bentonite producing state of Brazil. Besides the advantage of abundance of bentonite clays, its transformation in organoclay is a simple method and there is only little study about the commercialization of Brazilian organoclays. In this work, Brazilian bentonite clay was organophilized with different quantity of a quaternary ammonium salt, such as 100, 125 and 150 wt.% in relation to Cationic Exchange Capacity (CEC) of the clay. The clays were characterized by X-ray Fluorescence (XRF), X-ray Diffraction (XRD), Thermogravimetry (TG) and Nuclear Magnetic Resonance (NMR). It was observed that with increasing amount of salt the degree of dispersion of the clay increased, leading in some cases to the delamination of the clay layers and its loss of thermal stability. (author)

  19. Quaternary geology of the Bellevue area in Blaine and Camas Counties, Idaho

    Science.gov (United States)

    Schmidt, Dwight Lyman

    1962-01-01

    The Bellevue area covers about 350 square miles of a foothill belt between the Rocky Mountains to the north and the Snake River plains to the south. Complexly deformed impure quartzites and limestones of the Mississippian Milligen and Pennsylvanian-Permian Wood River formations were intruded by large bodies of quartz diorite and granodiorite along regional structures trending northwesterly; the intrusions are part of the Cretaceous Idaho batholith. Erosional remnants of the Challis volcanics, dominantly latitic to andesitic in composition and early(?) to middle Tertiary in age, rest unconformably on the older rocks. A sequence of Pliocene Rhyolitic ash flows and basaltic lava flows unconformably overlies the Challis and older rocks and is in turn unconformably overlain by olivine basalt of late Pliocene or early Quaternary age. The main valleys of the area, partly Erosional and partly structural in origin, are underlaind by late Quaternary olivine basalt flows (Snake River basalt) and intercalated lacustrine, fluvial, proglacial sediments. The Big Wood River, the master stream of the area, flows southward through a narrow steep-sided valley in the mountainous country north of the Bellevue area and debouches into a broad alluvial valley, the Wood River Valley, in the foothill belt. The valley has the shape of an isosceles triangle with a ten mile long, east-west base consisting of a ridge of Pliocene volcanics which separates the valley from the Snake River Plains to the south. The river now flows through a narrow gap in the southwest corner of the triangle. A similar, but wider, gap around the east end of the ridge was formerly occupied by the river. The river has been shifted back and forth between these two gaps at least four times during an interval in which six late Quaternary basalt flows erupted in the Bellevue area. Two of the flows caused direct diversion of the river and another was influential in bringing about a diversion on an aggradational fan upstream

  20. Perfluorinated quaternary ammonium salts of polyoxometalate anions: Fluorous biphasic oxidation catalysis with and without fluorous solvents

    Energy Technology Data Exchange (ETDEWEB)

    Maayan, Galia; Fish, Richard H.; Neumann, Ronny

    2003-05-28

    Perfluorinated quaternary ammonium cations, [CF{sub 3}(CF{sub 2}){sub 7}(CH{sub 2}){sub 3}]{sub 3}CH{sub 3}N{sup +} (RFN{sup +}), were synthesized and used as counter cations for the [WZnM{sub 2}(H{sub 2}O){sub 2}(ZnW{sub 9}O{sub 34}){sub 2}]{sup 12-} (M = Mn(II), Zn(II)), polyoxometalate. The (RFN{sup +}){sub 12}[WZnM{sub 2}(H{sub 2}O){sub 2}(ZnW9O{sub 34}){sub 2}] compounds were fluorous biphasic catalysts for alcohol and alkenol oxidation, and alkene epoxidation with aqueous hydrogen peroxide. Reaction protocols with or without a fluorous solvent were tested. The catalytic activity and selectivity was affected both by the hydrophobicity of the solvent and the substrate.

  1. Seismogenic structures in Quaternary lacustrine deposits of Lake Van (eastern Turkey

    Directory of Open Access Journals (Sweden)

    Üner Serkan

    2014-07-01

    Full Text Available Soft-sediment deformation structures formed by liquefaction and/or fluidisation of unconsolidated sediments due to seismic shocks are frequent in the Quaternary sandy, silty and clayey deposits of Lake Van. They are present in both marginal and deep lacustrine facies. Their morphology and interpreted genesis imply that they should be considered as fluid-escape structures (dish and pillar structures, flame structures and sand volcanoes, contorted structures (simple and complex convolutions and ball-and-pillow structures and other structures (disturbed layers and slump structures. The most recently formed structures are related to the October 23rd, 2011 Van-Tabanli (M 7.2 earthquake. The existence of seismites at various stratigraphic levels in the lacustrine deposits is indicative of tectonic activity that frequently triggered earthquakes with magnitudes of 5 or more, affecting the Lake Van Basin.

  2. Structure of the quaternary complex between SRP, SR, and translocon bound to the translating ribosome.

    Science.gov (United States)

    Jomaa, Ahmad; Fu, Yu-Hsien Hwang; Boehringer, Daniel; Leibundgut, Marc; Shan, Shu-Ou; Ban, Nenad

    2017-05-19

    During co-translational protein targeting, the signal recognition particle (SRP) binds to the translating ribosome displaying the signal sequence to deliver it to the SRP receptor (SR) on the membrane, where the signal peptide is transferred to the translocon. Using electron cryo-microscopy, we have determined the structure of a quaternary complex of the translating Escherichia coli ribosome, the SRP-SR in the 'activated' state and the translocon. Our structure, supported by biochemical experiments, reveals that the SRP RNA adopts a kinked and untwisted conformation to allow repositioning of the 'activated' SRP-SR complex on the ribosome. In addition, we observe the translocon positioned through interactions with the SR in the vicinity of the ribosome exit tunnel where the signal sequence is extending beyond its hydrophobic binding groove of the SRP M domain towards the translocon. Our study provides new insights into the mechanism of signal sequence transfer from the SRP to the translocon.

  3. Organometallics and quaternary ammonium salts affect calcium ion desorption from lecithin liposome membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kral, T.E.; Kuczera, J.; Przestalski, S. [Dept. of Physics and Biophysics, Agricultural Univ., Wroclaw (Poland)

    2001-06-01

    The objective of the present work was to compare the effects of groups of tin and lead organometallic compounds and their mixtures with amphiphilic quaternary ammonium salts (QAS) on the process of calcium ion desorption from lecithin liposome membranes, as dependent on the properties of the hydrophilic and hydrophobic parts of QAS. In the investigations the method of radioactive labels was applied. Synergism and antagonism in the action of both groups of compounds were found. The effectiveness of the cooperation depended more on chain length of QAS compounds than on the size and polarity of their hydrophobic parts. The most effective of all compounds studied was a the mixture of benzyldimethylammonium chloride in a mixture with tripropyltin. Since the rate of calcium desorption proved to be a good measure of efficacy of biologically active surfactants, it seems that the conclusions reached in this paper may be useful for choosing compounds which are able to decontaminate the environment polluted with heavy metals. (orig.)

  4. Climate change not to blame for late Quaternary megafauna extinctions in Australia.

    Science.gov (United States)

    Saltré, Frédérik; Rodríguez-Rey, Marta; Brook, Barry W; Johnson, Christopher N; Turney, Chris S M; Alroy, John; Cooper, Alan; Beeton, Nicholas; Bird, Michael I; Fordham, Damien A; Gillespie, Richard; Herrando-Pérez, Salvador; Jacobs, Zenobia; Miller, Gifford H; Nogués-Bravo, David; Prideaux, Gavin J; Roberts, Richard G; Bradshaw, Corey J A

    2016-01-29

    Late Quaternary megafauna extinctions impoverished mammalian diversity worldwide. The causes of these extinctions in Australia are most controversial but essential to resolve, because this continent-wide event presaged similar losses that occurred thousands of years later on other continents. Here we apply a rigorous metadata analysis and new ensemble-hindcasting approach to 659 Australian megafauna fossil ages. When coupled with analysis of several high-resolution climate records, we show that megafaunal extinctions were broadly synchronous among genera and independent of climate aridity and variability in Australia over the last 120,000 years. Our results reject climate change as the primary driver of megafauna extinctions in the world's most controversial context, and instead estimate that the megafauna disappeared Australia-wide ∼13,500 years after human arrival, with shorter periods of coexistence in some regions. This is the first comprehensive approach to incorporate uncertainty in fossil ages, extinction timing and climatology, to quantify mechanisms of prehistorical extinctions.

  5. Immobilization of Phosphomolybdate Anions on the Surface of Magnetite Nanoparticles Modified with Quaternary Phosphonium Cations

    Directory of Open Access Journals (Sweden)

    M. Masteri-Farahani

    2013-06-01

    Full Text Available A new hybrid nanomaterial was developed by immobilization of phosphomolybdate anions on the surface of modified magnetite nanoparticles with quaternary phosphonium cations. Silica coated magnetic nanoparticles supported phosphonium cations, Ph3P+-SCMNPs, were prepared by covalent attachment of chloropropylsilyl groups on the surface of silica coated magnetite nanoparticles and next reaction with triphenylphosphine. Then, reaction of the prepared Ph3P+-SCMNPs nanomaterial with H3PMo12O40 resulted in the preparation of PMo-Ph3P+-SCMNPs hybrid nanomaterial. The PMo-Ph3P+-SCMNPs hybrid nanomaterial was characterized with different physicochemical methods such as FT-IR and ICP-AES spectroscopies, XRD, VSM, SEM, and TEM analyses. VSM analysis showed superparamagnetic properties of the prepared nanomaterial. TEM and SEM analyses indicated the aggregated nanoparticles with about 15 nm average size.

  6. Late Quaternary Paleohydrology of the Madre de Dios River, southwestern Amazon Basin, Peru

    Science.gov (United States)

    Rigsby, Catherine A.; Hemric, Erin M.; Baker, Paul A.

    2009-12-01

    Late Quaternary climatic and hydrologic variability triggered changes in fluvial deposition and erosion along the course of the Madre de Dios River, Peru, the largest tributary basin of the Madeira basin, itself the largest tributary basin of the Amazon. Three laterally extensive, Quaternary-age, terrace tracts are present within the Madre de Dios basin. Analysis of sedimentary facies, present in the modern cut banks and terraced sequences, along with radiocarbon dates on fossil wood and leaf material preserved in the terraced strata, allow reconstruction of the Late Quaternary depositional history of the sedimentary sequences, including determination of the approximate timing of aggradation and downcutting episodes and its relationship to the timing of past climate change in this portion of the Amazon basin and beyond. The Quaternary sediments underlying the terraces most often recorded deposition in a coarse-grained meandering fluvial system. The T3 terrace, the highest terrace, is underlain by the Miocene (?) Ipururi Formation, which is unconformably overlain by the late Miocene-Pleistocene (?) (> 48,000 cal yrs BP) Madre de Dios Formation, a multistory coarse-sandy to gravelly channel and point bar complex. The latter was downcut before 29,850 ± 100 cal yrs BP. This downcut landscape was infilled by meandering fluvial strata characterized by gravelly channel deposits in a sequence dominated by floodplain and lateral accretion deposits. These strata were in turn downcut to form the T2 terrace before 11,970 ± 100 cal yrs BP. A third episode of aggradation resulted in the deposition of a sand-dominated meandering channel complex that infilled the T2 valley and was subsequently downcut after 3780 ± 50 cal yrs BP. This most recent terrace is infilled by the modern fluvial sediment, which has been actively aggrading since at least 870 ± 50 cal yrs BP. Importantly, the Madre de Dios fluvial system actively aggraded between 30,000 and 25,000 cal yrs BP, (and likely

  7. Agulhas leakage as a key process in the modes of Quaternary climate changes.

    Science.gov (United States)

    Caley, Thibaut; Giraudeau, Jacques; Malaizé, Bruno; Rossignol, Linda; Pierre, Catherine

    2012-05-01

    Heat and salt transfer from the Indian Ocean to the Atlantic Ocean (Agulhas leakage) has an important effect on the global thermohaline circulation and climate. The lack of long transfer record prevents elucidation of its role on climate changes throughout the Quaternary. Here, we present a 1,350-ka accumulation rate record of the planktic foraminiferal species Globorotalia menardii. We demonstrate that, according to previous assumptions, the presence and reseeding of this fauna in the subtropical southeast Atlantic was driven by interocean exchange south of Africa. The Agulhas transfer strengthened at glacial ice-volume maxima for every glacial-interglacial transition, with maximum reinforcements organized according to a 400-ka periodicity. The long-term dynamics of Agulhas leakage may have played a crucial role in regulating meridional overturning circulation and global climate changes during the Mid-Brunhes event and the Mid-Pleistocene transition, and could also play an important role in the near future.

  8. Regulation of uridine kinase quaternary structure. Dissociation by the inhibitor CTP.

    Science.gov (United States)

    Payne, R C; Traut, T W

    1982-11-10

    Uridine kinase from mouse Ehrlich ascites cells can exist in a variety of different aggregation states, from monomer up to aggregates that may contain 32 or more subunits. With very crude enzyme preparations, uridine kinase activity is always associated with several different coexisting molecular weight species. Changes in the aggregation state are produced in the presence of normal effectors (orthophosphate, ATP and CTP) at physiological concentrations. With uridine kinase that has been purified 9,000-fold, enzyme activity is associated with only a single molecular weight species, but is still responsive to the same physiological effectors. In the presence of orthophosphate, uridine kinase has a molecular weight of 380,000 (appropriate for a dodecamer). In the presence of CTP, the enzyme dissociates with concomitant loss of activity. The dissociated enzyme can be reassociated to the native size. These results imply that alteration of the enzyme's quaternary structure by normal effectors constitutes a mechanism for regulating uridine kinase activity in vivo.

  9. Quaternary tectonics and basin history of Pahrump and Stewart Valleys, Nevada and California

    International Nuclear Information System (INIS)

    Hoffard, J.L.

    1991-05-01

    The Pahrump fault system is an active fault system located in Pahrump and Stewart Valleys, Nevada and California, in the southern part of the Basin and Range Province. This system is 50 km long by 30 km wide and is comprised of three fault zones: the right-lateral East Nopah fault zone, the right-oblique Pahrump Valley fault zone, and the normal West Spring Mountains fault zone. All three zones have geomorphic evidence for late Quaternary activity. Analysis of active fault patterns and seismic reflection lines suggests that the Pahrump basin has had a two-stage genesis, an early history associated with a period of low angle detachment faulting probably active 10-15 Ma, and a more recent history related to the present dextral shear system, probably active post-4 Ma

  10. {sup 13}C NMR and XPS characterization of anion adsorbent with quaternary ammonium groups prepared from rice straw, corn stalk and sugarcane bagasse

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Wei, E-mail: weicao@hqu.edu.cn; Wang, Zhenqian; Zeng, Qingling; Shen, Chunhua

    2016-12-15

    Highlights: • {sup 13}C NMR and XPS were successfully used to characterize quaternary ammonium groups in the surface of crop straw based anion adsorbents. • The results obtained from different kinds of crop straw material clearly confirmed the presence of quaternary ammonium groups. • The composition of C-groups and N-groups also were determined by curving fitting of high-resolution XPS C1 and N1 spectra. - Abstract: Despite amino groups modified crop straw has been intensively studied as new and low-cost adsorbent for removal of anionic species from water, there is still a lack of clear characterization for amino groups, especially quaternary ammonium groups in the surface of crop straw. In this study, we used {sup 13}C NMR and XPS technologies to characterize adsorbents with quaternary ammonium groups prepared from rice straw, corn stalk and sugarcane bagasse. {sup 13}C NMR spectra clearly showed the presence of quaternary ammonium groups in lignocelluloses structure of modified crop straw. The increase of nitrogen observed in XPS survey spectra also indicated the existence of quaternary ammonium group in the surface of the adsorbents. The curve fitting of high-resolution XPS N1s and C1s spectra were conducted to probe the composition of nitrogen and carbon contained groups, respectively. The results showed the proportion of quaternary ammonium group significantly increased in the prepared adsorbent’s surface that was dominated by methyl/methylene, hydroxyl, quaternary ammonium, ether and carbonyl groups. This study proved that {sup 13}C NMR and XPS could be successfully utilized for characterization of quaternary ammonium modified crop straw adsorbents.

  11. 13C NMR and XPS characterization of anion adsorbent with quaternary ammonium groups prepared from rice straw, corn stalk and sugarcane bagasse

    International Nuclear Information System (INIS)

    Cao, Wei; Wang, Zhenqian; Zeng, Qingling; Shen, Chunhua

    2016-01-01

    Highlights: • 13 C NMR and XPS were successfully used to characterize quaternary ammonium groups in the surface of crop straw based anion adsorbents. • The results obtained from different kinds of crop straw material clearly confirmed the presence of quaternary ammonium groups. • The composition of C-groups and N-groups also were determined by curving fitting of high-resolution XPS C1 and N1 spectra. - Abstract: Despite amino groups modified crop straw has been intensively studied as new and low-cost adsorbent for removal of anionic species from water, there is still a lack of clear characterization for amino groups, especially quaternary ammonium groups in the surface of crop straw. In this study, we used 13 C NMR and XPS technologies to characterize adsorbents with quaternary ammonium groups prepared from rice straw, corn stalk and sugarcane bagasse. 13 C NMR spectra clearly showed the presence of quaternary ammonium groups in lignocelluloses structure of modified crop straw. The increase of nitrogen observed in XPS survey spectra also indicated the existence of quaternary ammonium group in the surface of the adsorbents. The curve fitting of high-resolution XPS N1s and C1s spectra were conducted to probe the composition of nitrogen and carbon contained groups, respectively. The results showed the proportion of quaternary ammonium group significantly increased in the prepared adsorbent’s surface that was dominated by methyl/methylene, hydroxyl, quaternary ammonium, ether and carbonyl groups. This study proved that 13 C NMR and XPS could be successfully utilized for characterization of quaternary ammonium modified crop straw adsorbents.

  12. Cationic nanoparticles with quaternary ammonium-functionalized PLGA-PEG-based copolymers for potent gene transfection

    Science.gov (United States)

    Wang, Yan-Hsung; Fu, Yin-Chih; Chiu, Hui-Chi; Wang, Chau-Zen; Lo, Shao-Ping; Ho, Mei-Ling; Liu, Po-Len; Wang, Chih-Kuang

    2013-11-01

    The objective of the present work was to develop new cationic nanoparticles (cNPs) with amphiphilic cationic copolymers for the delivery of plasmid DNA (pDNA). Cationic copolymers were built on the synthesis of quaternary ammonium salt compounds from diethylenetriamine (DETA) to include the positively charged head group and amphiphilic multi-grafts. PLGA- phe-PEG- qDETA (PPD), phe-PEG- qDETA-PLGA (PDP), and PLGA- phe-PEG- qDETA-PLGA (PPDP) cationic copolymers were created by this moiety of DETA quaternary ammonium, heterobifunctional polyethylene glycol (COOH-PEG-NH2), phenylalanine ( phe), and poly(lactic- co-glycolic acid) (PLGA). These new cNPs were prepared by the water miscible solvent displacement method. They exhibit good pDNA binding ability, as shown in a retardation assay that occurred at a particle size of 217 nm. The zeta potential was approximately +21 mV when the cNP concentration was 25 mg/ml. The new cNPs also have a better buffering capacity than PLGA NPs. However, the pDNA binding ability was demonstrated starting at a weight ratio of approximately 6.25 cNPs/pDNA. Gene transfection results showed that these cNPs had transfection effects similar to those of Lipofectamine 2000 in 293T cells. Furthermore, cNPs can also transfect human adipose-derived stem cells. The results indicate that the newly developed cNP is a promising candidate for a novel gene delivery vehicle.

  13. Evidence for Quaternary earthquakes from paleo-fluidization structures along the Pernambuco lineament (NE-Brazil).

    Science.gov (United States)

    Nestola, Yago; Balsamo, Fabrizio; Hilario Rego Bezerra, Francisco; Cézar Costa Nogueira, Fancisco; Storti, Fabrizio

    2014-05-01

    Plate tectonics theory postulate that seismicity is mostly restricted to the plate's boundaries. Nevertheless, intraplate earthquakes occur in stable continental areas such as the NE-Brazilian craton, where seismicity is clustered along fault systems reactivating major Neoproterozoic shear zones. Moreover, evidence for tectonic activity is recorded in the Cenozoic post-rift formations, widely outcropping along the coast of the NE-Brazilian passive margin. To investigate such unexpected seismic and tectonic activity we performed a structural field survey along the coastal segment of the Pernambuco shear zone, where the Miocene sandstone of the Barreiras Fm. and the overlying Quaternary post-Barreiras deposits extensively crop out. They are separated by a Tortonian lateritic paleosoil and are affected by mainly extensional faulting, associated with some strike-slip deformation, clustered in N-S, WNW-ESE, and NE-SW trends. In the proximity of the Pernambuco shear zone, in the hinterland of the Recife town, we found evidence for paleo-fluidization structures in post-Barreiras deposits, where mobilized materials include cm-dm-sized, heterogeneous angular clasts in a sandy-dominated matrix. The extent of the exposed fluidized bodies exceeds ~50 m in active quarry walls, the maximum thickness reaches ~3 m, and the depth of fluidization is estimated to be about 30 m. The top seal of fluidized material was provided by a ~80 cm thick clay layer. Such fluidizations are located few hundreds meters far from a major NE-SW-trending, sin-sedimentary extensional fault zone developed in Quaternary deposits, which is consistent with a left-lateral strike-slip sense of shear of the Pernambuco shear zone. Our results further improve the knowledge of paleo-seismic activity along the Pernambuco shear zone and, in particular, provide additional information for the seismic hazard assessment in the high-density populated area of the Recife town.

  14. Cationic nanoparticles with quaternary ammonium-functionalized PLGA–PEG-based copolymers for potent gene transfection

    International Nuclear Information System (INIS)

    Wang, Yan-Hsung; Fu, Yin-Chih; Chiu, Hui-Chi; Wang, Chau-Zen; Lo, Shao-Ping; Ho, Mei-Ling; Liu, Po-Len; Wang, Chih-Kuang

    2013-01-01

    The objective of the present work was to develop new cationic nanoparticles (cNPs) with amphiphilic cationic copolymers for the delivery of plasmid DNA (pDNA). Cationic copolymers were built on the synthesis of quaternary ammonium salt compounds from diethylenetriamine (DETA) to include the positively charged head group and amphiphilic multi-grafts. PLGA-phe-PEG-qDETA (PPD), phe-PEG-qDETA-PLGA (PDP), and PLGA-phe-PEG-qDETA-PLGA (PPDP) cationic copolymers were created by this moiety of DETA quaternary ammonium, heterobifunctional polyethylene glycol (COOH-PEG-NH 2 ), phenylalanine (phe), and poly(lactic-co-glycolic acid) (PLGA). These new cNPs were prepared by the water miscible solvent displacement method. They exhibit good pDNA binding ability, as shown in a retardation assay that occurred at a particle size of ∼217 nm. The zeta potential was approximately +21 mV when the cNP concentration was 25 mg/ml. The new cNPs also have a better buffering capacity than PLGA NPs. However, the pDNA binding ability was demonstrated starting at a weight ratio of approximately 6.25 cNPs/pDNA. Gene transfection results showed that these cNPs had transfection effects similar to those of Lipofectamine 2000 in 293T cells. Furthermore, cNPs can also transfect human adipose-derived stem cells. The results indicate that the newly developed cNP is a promising candidate for a novel gene delivery vehicle

  15. Deconstructing mammal dispersals and faunal dynamics in SW Europe during the Quaternary

    Science.gov (United States)

    Palombo, Maria Rita

    2014-07-01

    This research aims to investigate the relationships between climate change and faunal dynamics in south-west Europe, disentangling the asynchronous and diachronous dispersal bioevents of large mammals across geographical and ecological boundaries, analysing biodiversity and its changes through time. The analysis of local versus regional biological dynamics may shed new light on whether turnovers and ecological and evolutionary changes developed because of global climate changes and related phenomena, or because of intrinsic biological factors. The SW European Quaternary fossil record is particularly suitable for studying the role of climate change at local and regional levels because of the complex physiographic and climatic heterogeneity of the study area, the presence of important geographical/ecological barriers and the complex history of invasions of species of varying geographical origin and provenance. The data base consists of taxonomically revised lists of large mammal species from selected SW European local faunal assemblages ranging in age from the Early to the late Middle Pleistocene (middle Villafranchian to early Aurelian European Land Mammal Ages). The new biochronological scheme proposed here allows for the comparison of local turnovers and biodiversity trends, yielding a better understanding of the action of geographical/ecological barriers that either prevented the range of some taxa from reaching some regions or caused delays in the dispersal of a taxon in some territories. The results obtained provide evidence that major environmental perturbations, triggering dispersal events and removing keystone species, modified the structure of the pre-existing mammalian faunas, merging previously independently-evolved taxa into new palaeo-communities. The coupled action of climatic changes and internal biotic dynamics thus caused the Quaternary SW European faunal complexes to significantly restructure. Diachroneity in local turnover across the study area

  16. Latest Quaternary palaeoceanographic change in the eastern North Atlantic based upon a dinoflagellate cyst event ecostratigraphy

    Directory of Open Access Journals (Sweden)

    Rex Harland

    2016-05-01

    Full Text Available The analyses of dinoflagellate cyst records, from the latest Quaternary sediments recovered from DSDP Core 610A taken on the Feni Ridge in the southern Rockall Trough, and part of core MD01-2461 on the continental margin of the Porcupine Seabight in the eastern North Atlantic Ocean, has provided evidence for significant oceanographic change encompassing the Last Glacial Maximum (LGM and part of the Holocene. This together with other published records has led to a regional evaluation of oceanographic change in the eastern North Atlantic over the past 68 ka, based upon a distinctive dinoflagellate event ecostratigraphy. These changes reflect changes in the surface waters of the North Atlantic Current (NAC, and perhaps the deeper thermohaline Atlantic Meridional Overturning Circulation (AMOC, driving fundamental regime changes within the phytoplanktonic communities. Three distinctive dinoflagellate cyst associations based upon both factor and cluster analyses have been recognised. Associations characterised by Bitectatodinium tepikiense (between 61.1 ± 6.2 to 13.4 ± 1.1 ka BP, Nematosphaeropsis labyrinthus (between 10.5 ± 0.3 and 11.45 ± 0.8 ka. BP, and the cyst of Protoceratium reticulatum (between 8.5 ± 0.9 and 5.2 ± 1.3 ka. BP indicate major change within the eastern North Atlantic oceanography. The transitions between these changes occur over a relatively short time span (c.1.5 ka, given our sampling resolution, and have the potential to be incorporated into an event stratigraphy through the latest Quaternary as recommended by the INTIMATE (INTegrating Ice core, MArine and TErrestrial records group. The inclusion of a dinoflagellate cyst event stratigraphy would highlight changes within the phytoplankton of the North Atlantic Ocean as a fully glacial world changed to our present interglacial.

  17. Colloquium paper: Megafauna biomass tradeoff as a driver of Quaternary and future extinctions.

    Science.gov (United States)

    Barnosky, Anthony D

    2008-08-12

    Earth's most recent major extinction episode, the Quaternary Megafauna Extinction, claimed two-thirds of mammal genera and one-half of species that weighed >44 kg between approximately 50,000 and 3,000 years ago. Estimates of megafauna biomass (including humans as a megafauna species) for before, during, and after the extinction episode suggest that growth of human biomass largely matched the loss of non-human megafauna biomass until approximately 12,000 years ago. Then, total megafauna biomass crashed, because many non-human megafauna species suddenly disappeared, whereas human biomass continued to rise. After the crash, the global ecosystem gradually recovered into a new state where megafauna biomass was concentrated around one species, humans, instead of being distributed across many species. Precrash biomass levels were finally reached just before the Industrial Revolution began, then skyrocketed above the precrash baseline as humans augmented the energy available to the global ecosystem by mining fossil fuels. Implications include (i) an increase in human biomass (with attendant hunting and other impacts) intersected with climate change to cause the Quaternary Megafauna Extinction and an ecological threshold event, after which humans became dominant in the global ecosystem; (ii) with continued growth of human biomass and today's unprecedented global warming, only extraordinary and stepped-up conservation efforts will prevent a new round of extinctions in most body-size and taxonomic spectra; and (iii) a near-future biomass crash that will unfavorably impact humans and their domesticates and other species is unavoidable unless alternative energy sources are developed to replace dwindling supplies of fossil fuels.

  18. Quaternary geology of the Boston area: Glacial events from Lake Charles to Lake Aberjona

    Science.gov (United States)

    Stone, Byron D.; Lane, John W.

    2014-01-01

    The multiple-glacial and glaciomarine Quaternary history of the Boston, Massachusetts area has been known generally since the earliest studies of the then newly recognized glacial deposits described by Prof. Louis Agassiz in the late1840’s and fossil marine shells in the drift in the 1850’s. Attention then turned to possible glacial erosional effects on the preglacial bedrock physiography, as related to rock units and structure, and to the challenges of defining useful physical and lithic characteristics of the drift by Prof. W.O. Crosby and others, 1880-1900. The problems of deducing the relative stratigraphic order among such small, fossil-barren surficial sedimentary deposits, and extending knowledge gained from studies of postulated ancient glacial lakes to a regional understanding of the history of many lakes during the retreat of the ice sheet required field work and use of geologic maps. With the advent of modern topographic maps in the 1880’s, the early period of discovery included field studies of glacial lake deposits in local river basins in the Boston region, basins that drain northward, thereby creating glacial lake basins dammed by the ice margin as it retreated to the north. Guided by M.I.T. and Harvard professors W.O. Crosby, N.S. Shaler, J.B. Woodworth, W.M. Davis, and others in the 1880-1920 period, the first Quaternary glacial stratigraphers were students (e.g. Crosby and Grabau, 1896, Clapp, 1905, Fuller 1905, Goldthwaite 1906, Grabau, 1906, Taylor, Tight).

  19. Hydrogeological Investigations of the Quaternary Aquifeer in the Northern Part of El-Sharkia Governorate, Egypt

    International Nuclear Information System (INIS)

    El-Sayed, S.A.; Ezz El Din, M.R.; Deyab, M.E.

    2011-01-01

    The hydraulic characteristics of surficial soils and materials of the Quaternary aquifer in the northern part of El-Sharkia Governorate were investigated. The surficial soil zone represents an aquitard for the aquifer and mainly composed of fine textured materials having vertical hydraulic conductivity ranged from 1.4 x10 -6 cm/sec to 2.15x10 -2 cm/sec. The semi-confined Quaternary aquifer is formed of sand and gravel with occasional clay lenses. The groundwater levels ranged from 9 m (MSL) to 5 m (MSL). The major trend of groundwater flow was from south to north and northwest directions. Another minor flow trend was observed to be from southwest to northeast direction. The aquifer is essentially recharged from Ismaillia Canal. The hydraulic gradient through the flow path was 1.9 x10 -4 , averagely. The hydraulic conductivity values differ vertically and laterally indicating the heterogeneity and anisotropy of the aquifer materials. They ranged from 40.1 to 222 m/day with an average value of about 95.8 m/day. The chemical compositions of groundwater and surface water bodies (canals and drains) were investigated. The chemistry of all water bodies was characterized by a basic nature (ph =7.2-7.9) and showed different salinities values and various hydrochemical facies. The average salinities values were 318.1 mg/l for canal water, 1013.4 mg/l for groundwater and 1260 mg/l for drain water. Canal water was fresh while groundwater and drain were fresh to brackish. The reasons causing the changes in salinity and hydrochemical facies were investigated using the relationships among water dissolved constituents and trends of ionic ratios. Subsurface flow, infiltration, evaporation, ion exchange, leaching, and dissolution were the hydrochemical processes leading to the groundwater modification. The suitability of groundwater and surface water for different uses are discussed and evaluated according to the international standards.

  20. Human Antibodies that Recognize Novel Immunodominant Quaternary Epitopes on the HIV-1 Env Protein.

    Science.gov (United States)

    Hicar, Mark D; Chen, Xuemin; Sulli, Chidananda; Barnes, Trevor; Goodman, Jason; Sojar, Hakimuddin; Briney, Bryan; Willis, Jordan; Chukwuma, Valentine U; Kalams, Spyros A; Doranz, Benjamin J; Spearman, Paul; Crowe, James E

    2016-01-01

    Numerous broadly neutralizing antibodies (Abs) target epitopes that are formed or enhanced during mature HIV envelope formation (i.e. quaternary epitopes). Generally, it is thought that Env epitopes that induce broadly neutralizing Abs are difficult to access and poorly immunogenic because of the characteristic oligomerization, conformational flexibility, sequence diversity and extensive glycosylation of Env protein. To enhance for isolation of quaternary epitope-targeting Abs (QtAbs), we previously used HIV virus-like particles (VLPs) to bind B cells from long-term non-progressor subjects to identify a panel of monoclonal Abs. When expressed as recombinant full-length Abs, a subset of these novel Abs exhibited the binding profiles of QtAbs, as they either failed to bind to monomeric Env protein or showed much higher affinity for Env trimers and VLPs. These QtAbs represented a significant proportion of the B-cell response identified with VLPs. The Ab genes of these clones were highly mutated, but they did not neutralize common HIV strains. We sought to further define the epitopes targeted by these QtAbs. Competition-binding and mapping studies revealed these Abs targeted four separate epitopes; they also failed to compete for binding by Abs to known major neutralizing epitopes. Detailed epitope mapping studies revealed that two of the four epitopes were located in the gp41 subunit of Env. These QtAbs bound pre-fusion forms of antigen and showed differential binding kinetics depending on whether oligomers were produced as recombinant gp140 trimers or as full-length Env incorporated into VLPs. Antigenic regions within gp41 present unexpectedly diverse structural epitopes, including these QtAb epitopes, which may be targeted by the naturally occurring Ab response to HIV infection.

  1. Megafauna biomass tradeoff as a driver of Quaternary and future extinctions

    Science.gov (United States)

    Barnosky, Anthony D.

    2008-01-01

    Earth's most recent major extinction episode, the Quaternary Megafauna Extinction, claimed two-thirds of mammal genera and one-half of species that weighed >44 kg between ≈50,000 and 3,000 years ago. Estimates of megafauna biomass (including humans as a megafauna species) for before, during, and after the extinction episode suggest that growth of human biomass largely matched the loss of non-human megafauna biomass until ≈12,000 years ago. Then, total megafauna biomass crashed, because many non-human megafauna species suddenly disappeared, whereas human biomass continued to rise. After the crash, the global ecosystem gradually recovered into a new state where megafauna biomass was concentrated around one species, humans, instead of being distributed across many species. Precrash biomass levels were finally reached just before the Industrial Revolution began, then skyrocketed above the precrash baseline as humans augmented the energy available to the global ecosystem by mining fossil fuels. Implications include (i) an increase in human biomass (with attendant hunting and other impacts) intersected with climate change to cause the Quaternary Megafauna Extinction and an ecological threshold event, after which humans became dominant in the global ecosystem; (ii) with continued growth of human biomass and today's unprecedented global warming, only extraordinary and stepped-up conservation efforts will prevent a new round of extinctions in most body-size and taxonomic spectra; and (iii) a near-future biomass crash that will unfavorably impact humans and their domesticates and other species is unavoidable unless alternative energy sources are developed to replace dwindling supplies of fossil fuels. PMID:18695222

  2. Quaternary Geology and Surface Faulting Hazard: Active and Capable Faults in Central Apennines, Italy

    Science.gov (United States)

    Falcucci, E.; Gori, S.

    2015-12-01

    The 2009 L'Aquila earthquake (Mw 6.1), in central Italy, raised the issue of surface faulting hazard in Italy, since large urban areas were affected by surface displacement along the causative structure, the Paganica fault. Since then, guidelines for microzonation were drew up that take into consideration the problem of surface faulting in Italy, and laying the bases for future regulations about related hazard, similarly to other countries (e.g. USA). More specific guidelines on the management of areas affected by active and capable faults (i.e. able to produce surface faulting) are going to be released by National Department of Civil Protection; these would define zonation of areas affected by active and capable faults, with prescriptions for land use planning. As such, the guidelines arise the problem of the time interval and general operational criteria to asses fault capability for the Italian territory. As for the chronology, the review of the international literature and regulatory allowed Galadini et al. (2012) to propose different time intervals depending on the ongoing tectonic regime - compressive or extensional - which encompass the Quaternary. As for the operational criteria, the detailed analysis of the large amount of works dealing with active faulting in Italy shows that investigations exclusively based on surface morphological features (e.g. fault planes exposition) or on indirect investigations (geophysical data), are not sufficient or even unreliable to define the presence of an active and capable fault; instead, more accurate geological information on the Quaternary space-time evolution of the areas affected by such tectonic structures is needed. A test area for which active and capable faults can be first mapped based on such a classical but still effective methodological approach can be the central Apennines. Reference Galadini F., Falcucci E., Galli P., Giaccio B., Gori S., Messina P., Moro M., Saroli M., Scardia G., Sposato A. (2012). Time

  3. Agricultural contaminants in Quaternary aquitards: A review of occurrence and fate in North America

    Science.gov (United States)

    Rodvang, S. J.; Simpkins, W. W.

    2001-01-01

    The intensity of agriculture has increased significantly during the past 30 years, resulting in increased detection of agricultural contaminants (nutrients, pesticides, salts, trace elements, and pathogens) in groundwater. Till, glaciolacustrine, and loess deposits of Quaternary age compose the most common surficial deposits underlying agricultural areas in North America. Quaternary aquitards generally contain higher concentrations of solid organic carbon (SOC, as much as 1.4%), dissolved organic carbon (DOC, as much as 205 mg/L), and reduced sulfur (as much as 0.9%) than do aquifers. Their potential to sorb pesticides increases with the percent of older SOC, because diagenesis increases Koc. Denitrification consistently reduces nitrate to non-detectable levels in unweathered Quaternary aquitards. Organic carbon of Quaternary age is a more labile electron donor than carbon from shale clasts. Pyrite is a more labile electron donor than carbon in many instances. Unweathered Quaternary aquitards provide a high degree of protection for underlying aquifers, due to their large reserves of SOC and reduced sulfur for sorption and denitrification, combined with their typically low hydraulic conductivity. In contrast, agricultural contaminants are common in weathered Quaternary aquitards. Lower reserves of reduced sulfur and sorptive/labile organic carbon, and a higher bulk K due to fractures, limit their ability to attenuate nitrate and pesticides. Subsurface drainage, which is common in Quaternary aquitards because of high water tables, bypasses the attenuation capacity of Quaternary aquitards and facilitates the transport of agricultural contaminants to surface water. Résumé. L'agriculture s'est significativement accrue au cours des dernières 30 années, provoquant une détection plus fréquente dans les eaux souterraines de contaminants agricoles (engrais, pesticides, sels, éléments en traces et germes pathogènes). Les moraines, les formations glacio-lacustres et

  4. Evolution of the Lian River coastal basin in response to Quaternary marine transgressions in Southeast China

    Science.gov (United States)

    Tang, Yongjie; Zheng, Zhuo; Chen, Cong; Wang, Mengyuan; Chen, Bishan

    2018-04-01

    The coastal basin deposit in the Lian River plain is among the thickest Quaternary sequences along the southeastern coast of China. The clastic sediment accumulated in a variety of environmental settings including fluvial, channel, estuary/coastal and marine conditions. Detailed investigation of lithofacies, grain-size distributions, magnetic susceptibility, microfossils and chronology of marine core CN01, compared with regional cores, and combined with offshore seismic reflection profiles, has allowed us to correlate the spatial stratigraphy in the inner and outer plain and the seismic units. Grain size distribution analysis of core CN-01 through compositional data analysis and multivariate statistics were applied to clastic sedimentary facies and sedimentary cycles. Results show that these methods are able to derive a robust proxy information for the depositional environment of the Lian River plain. We have also been able to reconstruct deltaic evolution in response to marine transgressions. On the basis of dating results and chronostratigraphy, the estimated age of the onset of deposition in the Lian River coastal plain was more than 260 kyr BP. Three transgressive sedimentary cycles revealed in many regional cores support this age model. Detailed lithological and microfossil studies confirm that three marine (M3, M2 and M1) and three terrestrial (T3, T2 and T1) units can be distinguished. Spatial correlation between the inner plain, outer plain (typical cores characterized by marine transgression cycles) and offshore seismic reflectors reveals coherent sedimentary sequences. Two major boundaries (unconformity and erosion surfaces) can be recognized in the seismic profiles, and these correspond to weathered reddish and/or variegated clay in the study core, suggesting that Quaternary sediment changes on the Lian River plain were largely controlled by sea-level variations and coastline shift during glacial/interglacial cycles.

  5. Quaternary Geochronology, Paleontology, and Archaeology of the Upper San Pedro River Valley, Sonora, Mexico

    Science.gov (United States)

    Gaines, E. P.

    2013-12-01

    This poster presents the results of multi-disciplinary investigations of the preservation and extent of Quaternary fossil-bearing strata in the San Pedro River Valley in Sonora, Mexico. Geologic deposits in the portions of the San Pedro Valley in southern Arizona contain one of the best late Cenozoic fossil records known in North America and the best record of early humans and extinct mammals on the continent. The basin in the U.S. is one of the type locations for the Blancan Land Mammal Age. Hemiphilian and Irvingtonian fossils are common. Rancholabrean remains are widespread. Strata in the valley adjacent to the international border with Mexico have yielded the densest concentration of archaeological mammoth-kill sites known in the western hemisphere. Despite more than 60 years of research in the U.S., however, and the fact that over one third of the San Pedro River lies south of the international boundary, little has been known about the late Cenozoic geology of the valley in Mexico. The study reported here utilized extensive field survey, archaeological documentation, paleontological excavations, stratigraphic mapping and alluvial geochronology to determine the nature and extent of Quaternary fossil-bearing deposits in the portions of the San Pedro Valley in Sonora, Mexico. The results demonstrate that the Plio-Pleistocene fossil -bearing formations known from the valley in Arizona extend into the uppermost reaches of the valley in Mexico. Several new fossil sites were discovered that yielded the remains of Camelids, Equus, Mammuthus, and other Proboscidean species. Late Pleistocene archaeological remains were found on the surface of the surrounding uplands. AMS radiocarbon dating demonstrates the widespread preservation of middle- to late- Holocene deposits. However, the late Pleistocene deposits that contain the archaeological mammoth-kill sites in Arizona are absent in the valley in Mexico, and are now known to be restricted to relatively small portions of

  6. Preliminary results of paleoseismic investigations of Quaternary faults on eastern Yucca Mountain, Nye County, Nevada

    International Nuclear Information System (INIS)

    Menges, C.M.; Oswald, J.A.; Coe, J.A.

    1995-01-01

    Site characterization of the potential nuclear waste repository at Yucca Mountain, Nevada, requires detailed knowledge of the displacement histories of nearby Quaternary faults. Ongoing paleoseismic studies provide data on the amount and rates of Quaternary activity on the Paintbrush Canyon, Bow Ridge, and Stagecoach Road faults along the eastern margin of the mountain over varying time spans of 0-700 ka to perhaps 0-30 ka, depending on the site. Preliminary stratigraphic interpretations of deposits and deformation at many logged trenches and natural exposures indicate that each of these faults have experienced from 3 to 8 surface-rupturing earthquakes associated with variable dip-slip displacements per event ranging from 5 to 115 cm, and commonly in the range of 20 to 85 cm. Cumulative dip-slip offsets of units with broadly assigned ages of 100-200 ka are typically less than 200 cm, although accounting for the effects of possible left normal-oblique slip could increase these displacements by factors of 1.1 to 1.7. Current age constraints indicate recurrence intervals of 10 4 to 10 5 years (commonly between 30 and 80 k.y.) and slip rates of 0.001 to 0.08 mm/yr (typically 0.01-0.02 mm/yr). Based on available timing data, the ages of the most recent ruptures varies among the faults; they appear younger on the Stagecoach Road Fault (∼5-20 ka) relative to the southern Paintbrush Canyon and Bow Ridge faults (∼30-100 ka)

  7. National Health Information Center

    Science.gov (United States)

    ... About ODPHP Food and Nutrition Physical Activity Health Literacy Health Care Quality Healthy People healthfinder health.gov About ODPHP National Health Information Center National Health Information Center The National Health ...

  8. Find a Health Center

    Data.gov (United States)

    U.S. Department of Health & Human Services — HRSA Health Centers care for you, even if you have no health insurance – you pay what you can afford based on your income. Health centers provide services that...

  9. New Mexico Convention Centers

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This dataset provides an initial version of the locations of convention centers in New Mexico, in point form, with limited attributes, compiled using available data...

  10. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Center Carbon Monoxide Information Center En Español The Invisible Killer Carbon monoxide, also known as CO, is called the "Invisible Killer" because it's a colorless, odorless, poisonous gas. ...

  11. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... OnSafety Blog Safety Education Centers Neighborhood Safety Network Community Outreach Resource Center Toy Recall Statistics CO Poster ... Sitemap RSS E-mail Inside CPSC Accessibility Privacy Policy Budget, Performances & Finance Open Government Freedom of Information ( ...

  12. Center for Functional Nanomaterials

    Data.gov (United States)

    Federal Laboratory Consortium — The Center for Functional Nanomaterials (CFN) explores the unique properties of materials and processes at the nanoscale. The CFN is a user-oriented research center...

  13. Tornadoes: A Center Approach.

    Science.gov (United States)

    Christman-Rothlein, Liz; Meinbach, Anita M.

    1981-01-01

    Information is given on how to put together a learning center. Discusses information and activity packets for a complete learning center on tornadoes including objectives, directions, materials, photographs of physical arrangements, and posttest. (DC)

  14. Genetic Science Learning Center

    Science.gov (United States)

    Genetic Science Learning Center Making science and health easy for everyone to understand Home News Our Team What We Do ... Collaboration Conferences Current Projects Publications Contact The Genetic Science Learning Center at The University of Utah is a ...

  15. Hydrologic Engineering Center

    Data.gov (United States)

    Federal Laboratory Consortium — The Hydrologic Engineering Center (HEC), an organization within the Institute for Water Resources, is the designated Center of Expertise for the U.S. Army Corps of...

  16. Wound care centers

    Science.gov (United States)

    ... center; Ischemic ulcer - wound center References Kim PJ, Evans KK, Steinberg JS, Pollard ME, Attinger CE. Critical ... A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among ...

  17. NIH Clinical Centers

    Data.gov (United States)

    Federal Laboratory Consortium — The NIH Clinical Center consists of two main facilities: The Mark O. Hatfield Clinical Research Center, which opened in 2005, houses inpatient units, day hospitals,...

  18. Day Care Centers

    Data.gov (United States)

    Department of Homeland Security — This database contains locations of day care centers for 50 states and Washington D.C. and Puerto Rico. The dataset only includes center based day care locations...

  19. MARYLAND ROBOTICS CENTER

    Data.gov (United States)

    Federal Laboratory Consortium — The Maryland Robotics Center is an interdisciplinary research center housed in the Institute for Systems Research (link is external)within the A. James Clark School...

  20. Asymmetric Conjugate Addition of α-Cyanoketones to Enones Using Diaminomethylenemalononitrile Organocatalyst.

    Science.gov (United States)

    Nakashima, Kosuke; Noda, Yuta; Hirashima, Shin-Ichi; Koseki, Yuji; Miura, Tsuyoshi

    2018-02-16

    A diaminomethylenemalononitrile organocatalyst efficiently catalyzed the asymmetric conjugate addition of α-cyanoketones to vinyl ketones to give the corresponding 1,5-dicarbonyl compounds, which bear an all-carbon quaternary stereogenic center with high enantioselectivities. This report is the first example of the asymmetric conjugate addition of α-cyanoketones to vinyl ketones using an organocatalyst.

  1. Late Quaternary Surface Rupture and Associated Transpressive Uplift on a Section of the State Line Fault in the south-central Amargosa Desert Basin, Southwestern Nevada

    Science.gov (United States)

    Menges, C. M.; Fridrich, C.; Blakely, R. J.; Thompson, R. A.

    2003-12-01

    New geomorphic, geophysical, and structural data indicate that a section of the Pahrump-Stewart Valley (State Line) fault on the northern piedmont of the Resting Spring Range is associated with late Quaternary surface rupture and related transpressive domal uplift. Detailed aeromagnetic and gravity data clearly image this northwest-trending strike-slip fault in the subsurface as a continuous multi-strand fault system that continues >35 km further northwest into the south-central Amargosa Desert basin than previously established. This continuation of the fault consists of a sigmoidal bend characterized by a constraining bend on the north flank of the Resting Spring Range, paired with a releasing bend on the north flank of the southeastern Funeral Mountains. Bedrock mapping in the Amargosa Desert indicates a cumulative late Cenozoic right-lateral displacement of ˜15 km across the entire fault zone. In the Resting Spring area, the major central strand of the State Line fault zone is inactive but offsets playa facies of the Artists Drive Formation (equivalent), internally folded into a giant southeast-plunging chevron syncline, against fluvial and playa margin facies of the same formation that are folded into a broad northwest-plunging anticline. These deformed Tertiary strata are exposed in the core of a large (10 x 18 km) domal Quaternary uplift, centered on the northern piedmont of the range, that coincides with a major transpressive left-step in the adjoining active trace of the fault zone. The domal uplift is indicated by persistent incision into Tertiary bedrock (1-5+ m deep) beneath stepped sequences of straths capped by thin and locally warped mid-Pleistocene to Holocene alluvial-gravel veneers. Quaternary activity on the fault zone in this area is now focused on a strand along the northern and eastern border of the uplifted area marked by a discontinuous, 8-10 km long series of aligned, en-echelon, or anastomosing fault scarps that commonly bound linear

  2. Center of buoyancy definition

    International Nuclear Information System (INIS)

    Sandberg, V.

    1988-12-01

    The center of buoyancy of an arbitrary shaped body is defined in analogy to the center of gravity. The definitions of the buoyant force and center of buoyancy in terms of integrals over the area of the body are converted to volume integrals and shown to have simple intuitive interpretations

  3. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... and Bans Report an Unsafe Product Consumers Businesses Home Safety Education Safety Education Centers Carbon Monoxide Information Center Carbon ... All CO Safety Guides ")); jQuery(".node-type-safety-education-center ... Camping Equipment Home Heating Equipment On Safety Blogs: CO Safety More ...

  4. Data Center Tasking.

    Science.gov (United States)

    Temares, M. Lewis; Lutheran, Joseph A.

    Operations tasking for data center management is discussed. The original and revised organizational structures of the data center at the University of Miami are also described. The organizational strategy addresses the functions that should be performed by the data center, anticipates the specialized skills required, and addresses personnel…

  5. Nuclear Reaction Data Centers

    International Nuclear Information System (INIS)

    McLane, V.; Nordborg, C.; Lemmel, H.D.; Manokhin, V.N.

    1988-01-01

    The cooperating Nuclear Reaction Data Centers are involved in the compilation and exchange of nuclear reaction data for incident neutrons, charged particles and photons. Individual centers may also have services in other areas, e.g., evaluated data, nuclear structure and decay data, reactor physics, nuclear safety; some of this information may also be exchanged between interested centers. 20 refs., 1 tab

  6. Minimum inhibition concentration and anti-fungal contact time of quaternary ammonium and ethylenediaminetetraacetic acid (EDTA mixture towards Candida Albicans isolate

    Directory of Open Access Journals (Sweden)

    Elizabeth Yunita

    2008-07-01

    Full Text Available The aim of this study is to determine the Minimum Inhibitory Concentration (MIC and the exposure time of the combination of quaternary ammonium compound with EDTA towards Candida albicans isolates from the 5 upper acrylic removable complete dentures. This experimental laboratory study was conducted based on a serial dilution of the combination of quaternary ammonium compound with EDTA towards Candida albicans in 3 replications and statistically analyzed according to Kruskal-Wallis method. The result showed that the MIC of the combination of quaternary ammonium compound with EDTA towards Candida albicans was in 1/8000 concentration with minimum 8 hours exposure time. This study concluded that the combination of quaternary ammonium compound with EDTA had an antifungal activity towards Candida albicans at 1/8000 concentration in 8 hours exposure time.

  7. Water oxidation catalysis: an amorphous quaternary Ba-Sr-Co-Fe oxide as a promising electrocatalyst for the oxygen-evolution reaction.

    Science.gov (United States)

    Zhang, Cuijuan; Berlinguette, Curtis P; Trudel, Simon

    2016-01-25

    We present an amorphous quaternary Ba-Sr-Co-Fe oxide (a-BSCF) with a specific stoichiometry, readily fabricated via a photochemical decomposition method. a-BSCF demonstrates high catalytic activity towards the oxygen-evolution reaction (OER).

  8. Late Quaternary paleoceanographic features as deduced from calcium carbonate and faunal changes of planktonic foraminifers in core samples from northeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Singh, A

    carbonate and planktonic foraminifers, with implications on paleoceanography of the Arabian Sea during late Quaternary. Paleoclimatic curve based on per cent variations of carbonate is substantiated by the faunal characteristics. Low value of cold...

  9. Study of the influence of pre-activation of vermiculite and concentration of the quaternary ammonium salt in obtaining of organovermiculita

    International Nuclear Information System (INIS)

    Silva, A.L.; Barboza, E.A.; Souza, F.K.A.; Neves, G.A.; Santana, L.N.L.

    2011-01-01

    Organoclays, are derived from the addition of quaternary ammonium salts in aqueous dispersions of natural clays or sodium. The aim of this study was to obtain organoclays from the intercalation of clay mineral vermiculite and quaternary ammonium salt Praepagem WB, thus, was used to study the concentrations of salt activation of Na 2 CO 3 , the cure time of this salt and varying the concentration the quaternary ammonium salt. The X-ray diffraction was used to determine whether there was a change in basal spacing after intercalation process with the quaternary ammonium salt. The process of organophilization of vermiculite, was confirmed by change in clay basal interplanar distance, which was 14.32 Å and after the addition of salt increased to 60.04 Å when activated for 5 days. (author)

  10. Optically stimulated luminescence and isothermal thermoluminescence dating of high sensitivity and well bleached quartz from Brazilian sediments: from Late Holocene to beyond the Quaternary?

    OpenAIRE

    Sawakuchi, André Oliveira; Mendes, Vinicius Ribau; Pupim, Fabiano do Nascimento; Mineli, Thays Desiree; Ribeiro, Ligia Maria Almeida Leite; Zular, Andre; Guedes, Carlos Conforti Ferreira; Giannini, Paulo César Fonseca; Nogueira, Luciana; Sallun Filho, William; Assine, Mario Luis

    2016-01-01

    ABSTRACT: The development of optically stimulated luminescence (OSL) dating of sediments has led to considerable advance in the geochronology of the Quaternary. OSL dating is a well established technique to determine sediment burial ages from tens of years to few hundred thousand years. Recent studies have shown that Quaternary sediments of Brazil are dominated by quartz grains with high luminescence sensitivity, allowing the determination of precise and reliable OSL burial ages. In this pape...

  11. Effect of a Quaternary Meteoroid Impact in Indo-China on the Surface Sedimentary Record

    Science.gov (United States)

    Carling, Paul; Songtham, Wickanet; Tada, Riuji; Tada, Toshihiro; Duangkrayon, Jaa

    2017-04-01

    Effects of meteoroid impacts on terrestrial geology primarily have been considered with respect of proximal effects near the impact location; such as cratering, fracturing and melt. However, other than the use of rare elements (iridium) as event markers and tektite chemistry for dating control, distal effects of impacts are less-well documented. Distal effects might include: fireball, air blast, heat, water vaporization, catastrophic flooding, earthquakes, ejecta fallout (tektites & dust), large quantities of N2O from shock heating of the atmosphere, release of CO2 and sulphur aerosols causing heating or cooling of atmosphere, IR radiation causing vegetation fires, smoke and pyrotoxins, and altered native rock geochemistry. Such processes may affect the distal surface geology, degrade vegetation cover and cause extirpation of flora and fauna. Quaternary sedimentary sections have been examined in northern and central Cambodia, in southern China and in north-east Thailand. These locality lie within the Australian strewn tektite field ̶ reliably dated to 0.77-0.78Ma BP ̶ just before the 0.80Ma BP Brunhes/Matayama reversal. The location of the primary impact crater (if any) is uncertain but a local major crater probably lies within central Laos or just offshore to the east. The described sections are considered distal from the main impact. Stratigraphic evidence indicates a temporal sequence of catastrophic stripping of alluvial-gravel surfaces followed by catastrophic redistribution of gravel (incorporating tektites), followed by deposition of atmospheric dust. Grain-size and grain-density trends, XRD, spherule distributions, luminescence profiles, tektite, and microtektite and shock quartz assay, are used to with the stratigraphic evidence to examine an hypothesis that the sections represent the distal effects of a meteorite. Additional insight is gained with respect to prior claims that large accumulations of woody debris in Thai Quaternary river terraces were due

  12. The Unseen Founders Of Quaternary Science - The Men Of Glasgow, Scotland (Invited)

    Science.gov (United States)

    Rose, J.

    2010-12-01

    Louis Agassiz (1807-1873) and Charles Lyell (1797-1875) are widely regarded as the founders of Quaternary Science, and there is no doubt that they played their part: Agassiz in 1840 presented and promoted his case for the wide-scale fluctuations of glaciers, and Lyell, through his books and contacts, did much to introduce the subject which we now know as climate change. However there are a number of individuals who contributed to the founding of Quaternary Science who are not so readily recognised and a remarkable fact is that a significant proportion were men without academic training or background who come from, or worked in Glasgow or the adjacent region of central Scotland. First amongst the Glaswegians was James Smith (1782-1867) who, in 1836 presented a paper to the Geological Society of London (where it was duly ignored) in which he suggested, on the basis of fossils dredged from the bed of the Clyde and experience of sailing around Iceland, that the climate of Scotland had been as cold as that of Iceland in the recent past. In 1841, Charles Maclaren (1782-1866) a journalist from Edinburgh, but using information based on raised shorelines near Glasgow proposed what we now know as the glacio-eustatic theory in which the variations in glacier extent control the level of the sea. Perhaps the most important of all was James Croll (1821- 1890) who worked on the theory of ice ages, based on orbital forcing, while janitor at the Andersonian Institute and Museum in Glasgow between 1859-1867. This work was the true precursor to the Milankovitch theory which provides the explanation for the major predictable elements of climate change. Robert Jack (1845-1921) from Irvine, southwest of Glasgow, while doing fieldwork for the British Geological Survey near Loch Lomond close to Glasgow, described in 1874 evidence for non-glacial conditions between tills and clearly recognised that climate could change from glacial to temperate and then glacial climate, before returning to

  13. Freshwater gastropods of Neogene and Quaternary lake systems of Europe - state of the art and outlook

    Science.gov (United States)

    Neubauer, Thomas A.; Harzhauser, Mathias; Mandic, Oleg; Kroh, Andreas

    2013-04-01

    Globally, about 4000 extant species of freshwater gastropod species have been described. In contrast, only 225 species are listed by MollBase2012 for North- and Central Europe. Many of these are rare species, limited to certain springs and in fact the typical diversity of gastropods in lakes of North and Central Europe is much lower. The high number is boosted by several highly speciose endemic radiations in long-lived ancient lakes, which are hotspots for biodiversity. These long-lived ancient lakes provide key examples for understanding evolutionary processes and therefore are intensively studied. During the Neogene, Europe's geodynamic history gave rise to several such long-lived lakes with conspicuous endemic radiations. However, these lacustrine systems are rare today as well as in the past compared to the enormous numbers of "normal" lakes. Most extant European lakes are mainly results of the Ice Ages and are due to their geologically temporary nature largely confined to the Pleistocene-Holocene. Also deposits of streams, springs, and groundwater, which today are inhabited by species-rich gastropod assemblages, are rarely preserved. Thus, the pre-Quaternary lacustrine record is biased towards long-lived systems. Apart from few general overviews precise studies on the γ-diversities of the post-Oligocene European lake systems and the shifting biodiversity in European freshwater systems through space and time are entirely missing. Even for the modern faunas, literature on large-scale freshwater gastropod diversity in extant lakes is scarce and lacks a statistical approach. Building upon a great amount of existing literature, a new project will provide the first detailed assessment of the composition of European freshwater gastropods during the Neogene and Quaternary at species, genus and family levels, with emphasis on lake faunas. The γ-diversity of several hundred modern and fossil European lakes will be evaluated. Data will be made available permanently for

  14. Optical analysis of lens-like Cu{sub 2}CdSnS{sub 4} quaternary alloy nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Odeh, Ali Abu; Ayub, R.M. [University Malaysia Perlis, Institute of Nano Electronic Engineering, Kangar, Perlis (Malaysia); Al-Douri, Y. [University Malaysia Perlis, Institute of Nano Electronic Engineering, Kangar, Perlis (Malaysia); University of Sidi-Bel-Abbes, Physics Department, Faculty of Science, Sidi-Bel-Abbes (Algeria); Ameri, M. [Universite Djilali Liabes de Sidi Bel- Abbes, Laboratoire Physico-Chimie des Materiaux Avances (LPCMA), Sidi-Bel-Abbes (Algeria); Bouhemadou, A. [University of Setif 1, Laboratory for Developing New Materials and Their Characterization, Setif (Algeria); Prakash, Deo [SMVD University, Faculty of Engineering, School of Computer Science and Engineering, Kakryal, Katra, J and K (India); Verma, K.D. [S.V. College, Material Science Research Laboratory, Department of Physics, Aligarh, U.P. (India)

    2016-10-15

    Cu{sub 2}CdSnS{sub 4} quaternary alloy nanostructures with different copper concentrations (0.2, 0.4, 0.6, 0.8 and 1.0 M) were successfully synthesized on n-type silicon substrates using spin coating technique with annealing temperature at 300 C. Optical properties were analyzed through UV-Vis and Photoluminescence spectroscopies, and thus, there is a change in energy band gap with increasing Cu concentration from 0.2 to 1.0 M. The structural properties of Cu{sub 2}CdSnS{sub 4} quaternary alloy nanostructures were investigated by X-ray diffraction. The particles size and shape have a direct relationship with copper concentration. Morphological and topographical studies were carried out by using scanning electron microscopy and atomic force microscopy. The obtained results are investigated to be available in the literature for future studies. (orig.)

  15. Synthesis and crystal structure of the quaternary compound AgFe{sub 2}GaTe{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, Gerzon E., E-mail: gerzon@ula.ve [Laboratorio de Cristalografía, Departamento de Química, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101 (Venezuela, Bolivarian Republic of); Quintero, Eugenio; Tovar, Rafael; Grima-Gallardo, Pedro; Quintero, Miguel [Centro de Estudio de Semiconductores, Departamento de Física, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101 (Venezuela, Bolivarian Republic of)

    2014-11-15

    Highlights: • New quaternary compound. • Synthesis from solid state reaction. • Crystal structure. • Rietveld refinement. - Abstract: The crystal structure of the quaternary compound AgFe{sub 2}GaTe{sub 4}, belonging to the system I–II{sub 2}–III–VI{sub 4}, was characterized by Rietveld refinement using X-ray powder diffraction data. The powder pattern was composed by 84.5% of the principal phase AgFe{sub 2}GaTe{sub 4} and 15.5% of the secondary phase FeTe. This material crystallizes with stannite structure in the tetragonal space group I-42m (N° 121), Z = 2, unit cell parameters a = 6.3409(2) Å, c = 12.0233(4) Å, V = 483.42(3) Å{sup 3}, and is isostructural with CuFe{sub 2}InSe{sub 4}.

  16. Inhibition of [3H]dopamine uptake into rat striatal slices by quaternary N-methylated nicotine metabolites

    International Nuclear Information System (INIS)

    Dwoskin, L.P.; Leibee, L.L.; Jewell, A.L.; Fang, Zhaoxia; Crooks, P.A.

    1992-01-01

    The effects of quaternary N-methylated nicotine derivatives were examined on in vitro uptake of [ 3 H]dopamine ([ 3 H]DA) in rat striatal slices. Striatal slices were incubated with a 10 μM concentration of the following compounds: N-methylnicotinium, N-methylnornicotinium, N-methylcotininium, N,N'-dimethylnicotinium and N'-methylnicotinium salts. The results clearly indicated that significant inhibition of [ 3 H]DA uptake occurred with those compounds possessing a N-methylpyridinium group; whereas, compounds that were methylated at the N'-pyrrolidinium position were less effective or exhibited no inhibition of [ 3 H]DA uptake. The results suggest that high concentrations of quaternary N-methylated nicotine metabolites which are structurally related to the neurotoxin MPP + , and which may be formed in the CNS, may protect against Parkinson's Disease and explain the inverse relationship between smoking and Parkinsonism reported in epidemiologic studies

  17. Design of quaternary logic circuit using quantum dot gate-quantum dot channel FET (QDG-QDCFET)

    Science.gov (United States)

    Karmakar, Supriya

    2014-10-01

    This paper presents the implementation of quaternary logic circuits based on quantum dot gate-quantum dot channel field effect transistor (QDG-QDCFET). The super lattice structure in the quantum dot channel region of QDG-QDCFET and the electron tunnelling from inversion channel to the quantum dot layer in the gate region of a QDG-QDCFET change the threshold voltage of this device which produces two intermediate states between its ON and OFF states. This property of QDG-QDCFET is used to implement multi-valued logic for future multi-valued logic circuit. This paper presents the design of basic quaternary logic operation such as inverter, AND and OR operation based on QDG-QDCFET.

  18. The Quaternary groundwater as the low temperature energy source for heat pumps in Małopolska Province

    Science.gov (United States)

    Kmiecik, Ewa; Tomaszewska, Barbara; Mazurkiewicz, Justyna

    2017-11-01

    The paper presents the assessment of using Quaternary groundwater as the low-temperature energy source for heat pumps in the Małopolska Province. The analysis demonstrates that the Małopolska region has potential to use Quaternary groundwater in low-temperature systems both in terms of potential well flow rates and water temperature. Water as a heat source must also meet the relevant requirements in terms of the physical and chemical parameters indicated by manufacturers of heat pumps as important for the proper operation of installations. The data for this study were obtained from the Polish Hydrogeological Survey (the PHS is carried out by the Polish Geological Institute — National Research Institute). In some cases, physical and chemical properties of water do not meet the requirements indicated by heat pump manufacturers. These requirements may be met by using recycled water or another medium whose parameters do not affect the life of the installation.

  19. Specialization in plant-hummingbird networks is associated with species richness, contemporary precipitation and quaternary climate-change velocity

    DEFF Research Database (Denmark)

    Dalsgaard, Bo; Magård, Else; Fjeldså, Jon

    2011-01-01

    patterns of contemporary biotic specialization and its drivers, we use network analysis to determine the degree of specialization in plant-hummingbird mutualistic networks sampled at 31 localities, spanning a wide range of climate regimes across the Americas. We found greater biotic specialization at lower...... latitudes, with latitude explaining 20-22% of the spatial variation in plant-hummingbird specialization. Potential drivers of specialization--contemporary climate, Quaternary climate-change velocity, and species richness--had superior explanatory power, together explaining 53-64% of the variation...... specialization. These results suggest that both ecological and evolutionary processes at Quaternary time scales can be important in driving large-scale geographical patterns of contemporary biotic specialization, at least for co-evolved systems such as plant-hummingbird networks....

  20. Quaternary paleoceanography of the deep Arctic Ocean based on quantitative analysis of Ostracoda

    Science.gov (United States)

    Cronin, T. M.; Holtz, T.R.; Whatley, R.C.

    1994-01-01

    Ostracodes were studied from deep Arctic Ocean cores obtained during the Arctic 91 expedition of the Polarstern to the Nansen, Amundsen and Makarov Basins, the Lomonosov Ridge, Morris Jesup Rise and Yermak Plateau, in order to investigate their distribution in Arctic Ocean deep water (AODW) and apply these data to paleoceanographic reconstruction of bottom water masses during the Quaternary. Analyses of coretop assemblages from Arctic 91 boxcores indicate the following: ostracodes are common at all depths between 1000 and 4500 m, and species distribution is strongly influenced by water mass characteristics and bathymetry; quantitative analyses comparing Eurasian and Canada Basin assemblages indicate that distinct assemblages inhabit regions east and west of the Lomonosov Ridge, a barrier especially important to species living in lower AODW; deep Eurasian Basin assemblages are more similar to those living in Greenland Sea deep water (GSDW) than those in Canada Basin deep water; two upper AODW assemblages were recognized throughout the Arctic Ocean, one living between 1000 and 1500 m, and the other, having high species diversity, at 1500-3000 m. Downcore quantitative analyses of species' abundances and the squared chord distance coefficient of similarity reveals a distinct series of abundance peaks in key indicator taxa interpreted to signify the following late Quaternary deep water history of the Eurasian Basin. During the Last Glacial Maximum (LGM), a GSDW/AODW assemblage, characteristic of cold, well oxygenated deep water > 3000 m today, inhabited the Lomonosov Ridge to depths as shallow as 1000 m, perhaps indicating the influence of GSDW at mid-depths in the central Arctic Ocean. During Termination 1, a period of high organic productivity associated with a strong inflowing warm North Atlantic layer occurred. During the mid-Holocene, several key faunal events indicate a period of warming and/or enhanced flow between the Canada and Eurasian Basins. A long

  1. Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

    Directory of Open Access Journals (Sweden)

    M.-C. Ciobanu

    2012-09-01

    Full Text Available An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion. Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG, within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG and Halobacteria within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria within Proteobacteria phylum, and also members of Bacteroidetes phylum. The second most abundant lineages were Actinobacteria and Firmicutes at the Gulf of Lion site and Chloroflexi at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: Alpha-, Gammaproteobacteria, Firmicutes and Actinobacteria. In molecular surveys, the Betaproteobacteria group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea levee. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence

  2. Late Quaternary river channel migrations of the Kura River in Transcaucasia - tectonic versus climatic causes

    Science.gov (United States)

    von Suchodoletz, Hans; Gärtner, Andreas; Hoth, Silvan; Umlauft, Josefine; Godoladze, Tea; Faust, Dominik

    2015-04-01

    Large-scale river channel migrations either in the form of avulsions or combing, i.e. progressive lateral migrations, are global phenomena during the Late Quaternary. Such channel migrations were triggered by tectonics, climate change, human activity or a combination of those factors. River channel migrations have the potential to cause significant human and economic losses. Thus, a more thorough knowledge about underlying causes and process rates is essential. Furthermore, such studies will elucidate the sensitivity or robustness of rivers to different external and internal forcing-agents, i.e. they help to identify the dominant drivers of regional landscape evolution. The Caucasus region is part of the active collision zone between the Africa-Arabian and the Eurasian plates, and is characterized by high current tectonic activity. Furthermore, significant environmental changes took place during the Late Quaternary, i.e. the shrinking or even disappearance of glaciers in the Greater and Lesser Caucasus or fundamental changes of the vegetation cover varying between woodland and grassland-dominated vegetation. The Kura River is the main gaining stream of the Transcaucasian Depression located between the Greater Caucasus Mountains in the north and the Lesser Caucasus Mountains in the south, and receives several tributaries from both mountain ranges. This study focusses on the middle course of the Kura River in eastern Georgia, SE of the city of Tbilisi. Integration of fluvial geomorphology, geochronology, heavy mineral analyses and seismo-tectonic analyses demonstrates that this part of the Kura River underwent large-scale channel migrations up to >10 km during Late Pleistocene and Holocene. It is interpreted that these movements followed both tectonic and climatic triggers: Whereas SW-ward migrations were caused by tectonic uplift in and SW-directed advance of the Kura fold and thrust belt as part of the Greater Caucasus, NE-ward migrations occurred during cold

  3. Three-dimensional sedimentary architecture of Quaternary deposits; a case study of environmental sedimentology (Bam, Iran)

    Science.gov (United States)

    Rezaei, K.; Guest, B.; Friedrich, A.; Fayazi, F.; Nakhaei, M.; Bakhtiari, H.; Nouri, L.

    2009-04-01

    Detailed 3-D analysis of the sedimentary structure and stratigraphy of these deposits allows for an accurate understand of sedimentary model of basin. This paper presents a case study in Bam (SE Iran) reconstructing the 3-D distribution of fluvial sediments based on a high resolution, process-orientated sedimentary facies classification and lithostratigraphy. We investigated the mean grain size with vertical and horizontal change of it, clay mineralogy, sediment texture, sedimentary structures, petrology and petrography and determination of paleo-environments and finally, we prepared two cross sections in S-N and W-E directions and a 3D block diagram for the situation of changes in subsurface sediments and compare them with the destruction rate map of earthquake in Bam city. Quaternary alluvial sediments are characterized by lithofacies deposited by braided river channels, debris flows and hyperconcentrated flows. The channel flow deposits constitute relatively well sorted, well imbricated and clast-supported gravels with coarse to medium sand matrix. Mostly poorly sorted, weakly imbricated to disorganized matrix supported pebble to boulder gravels with silty sand represent debris flow deposits. Hyperconcentrated flow deposits consist of clast-supported, poorly developed sorted polymodal gravel facies with poorly developed imbricated fabric, and generally occupy the lower parts of the terrace and fan sequences. The alternation from hyperconcentrated flow to channel flow deposits is predominant in the sequence, and is possibly the response to different climate modes. The high discharge and supply of sediments as well as the dispersal and deposition of these materials in the trunk stream is attributed to climatic perturbations during the Quaternary. These models allow quantifying the thickness and volume distribution of sandy gravel and clay deposits. We correlate these sedimentary units on the basis of lithofacies similarities, stratigraphic position. These

  4. Depth and stratigraphy of Quaternary deposits. Preliminary site description Laxemar subarea - version 1.2

    Energy Technology Data Exchange (ETDEWEB)

    Nyman, Helena [SWECO Position AB, Stockholm (Sweden)

    2005-09-01

    This report aims at describing the modelled Quaternary deposits (QD) depth according to six layers with different geological and hydrological properties in the Simpevarp regional model area. The program used in the modelling of QD depths is the GeoEditor, which is an ArcView3.3-extension. The input data used in the model consist of 102 boreholes and 328 observation points. As input is also a large number of observation points interpreted from geophysical investigations used; 1,087 points based on refraction seismic measurements (distributed in 31 profiles), 22 points from electrical soundings (VES) and 19,237 points from seismic and sediment echo sounding data. The outer part of the area has a low data density. Some of the used points are generally not very deep and do not describe the actual bedrock elevation. They do, however, describe the minimum QD depth at each location. A detailed topographical Digital Elevation Model (DEM), the maps of Quaternary deposits and outcrops were also used. The model is based on a three-layer-principle where each layer can be given similar properties. The uppermost layer, Z1, has been influenced by the impact from surface processes, e.g. roots and biological activity. The bottom layer, Z3, is characterized by contact with the bedrock and is corresponding to a till layer. The middle layer, Z2, is corresponding to a clay layer and assumed to have different hydraulic qualities than Z1 and Z3. Besides those layers, another three layers are also modelled; M1 corresponds to a peat layer, M2 answers to a glaciofluvial sediment layer and M3 corresponds to a layer with artificial fill. All layers can have thickness zero. The resulting model clearly shows the valleys with thicker depths of QD, surrounded by areas with thinner or no depths. The esker near Faarbo (Tunaaasen) is also distinctly marked in the south-western area. The northern and central part of the model area are characterized by numerous bedrock outcrops. The maximum depth of

  5. Late Quaternary landscape evolution in the Great Karoo, South Africa: Processes and drivers.

    Science.gov (United States)

    Oldknow, Chris; Hooke, Janet; Lang, Andreas

    2016-04-01

    The Great Karoo spans the north-central part of South Africa at a major climatic boundary. The characteristics, sequences, spatial patterns and drivers of river response to Late Quaternary climate changes in this region remain unclear due to the fragmentary alluvial/colluvial stratigraphic record and the lack of dated palaeoclimatic archives. Dendritic gully networks incised into deep deposits (up to 6 m) of colluvium and alluvium in the upper Sundays River catchment expose a legacy of "cut and fill" features. In 1st order tributaries, these are predominantly discontinuous palaeochannels and flood-outs with localised palaeosols, whereas in 2nd & 3rd order tributaries there are: 1) incised palaeo-geomorphic surfaces, 2) semi-continuous inset terrace sequences, 3) buried palaeo-gully topography. Using a combination of field mapping, logging of sediment outcrops, soil micromorphological and grain size analysis, mineral magnetic measurements and radiometric dating (OSL & 14C), we derive a stratigraphic evolution model which demonstrates a) the number of phases of incision, aggradation and pedogenesis, b) the spatial and temporal extent of each phase and c) the drivers of alluviation and associated feedbacks. Our reconstruction of regional valley alluviation indicates four distinct terrace units of contrasting depositional age. The base of the succession reflects slow aggradation under periglacial conditions associated with the Last Glacial Maximum. Subsequent channel entrenchment, causing terrace abandonment (T1) occurred in the deglacial period when vegetation and rainfall were in anti-phase. Re-instatement of connectivity with deep upland colluvial stores resulted in the injection of a pulse of sediment to valley floors, triggering compartmentalised backfilling (aggradation of T2) which propagated upstream as far as the second order drainage lines. This backfilling restructured the local hydrology, which, in concert with enhanced summer-rainfall, contributed to a

  6. Seismic influence in the Quaternary uplift of the Central Chile coastal margin, preliminary results.

    Science.gov (United States)

    Valdivia, D.; del Valle, F.; Marquardt, C.; Elgueta, S.

    2017-12-01

    In order to quantify the influence of NW striking potentially seismogenic normal faults over the longitudinal variation of the Central Chile Coastal margin uplift, we measured Quaternary marine terraces, which represent the tectonic uplift of the coastal margin. Movement in margin oblique normal faults occurs by co-seismic extension of major subduction earthquakes and has occurred in the Pichilemu fault, generating a 7.0 Mw earthquake after the 2010 8.8 Mw Maule earthquake.The coastal area between 32° and 34° S was selected due to the presence of a well-preserved sequence of 2 to 5 Quaternary marine terraces. In particular, the margin oblique normal NW-trending, SW-dipping Laguna Verde fault, south of Valparaiso (33° S) puts in contact contrasting morphologies: to the south, a flat coast with wide marine terraces is carved in both, Jurassic plutonic rocks and Neogene semi-consolidated marine sediments; to the north, a steeper scarp with narrower marine terraces, over 120 m above the corresponding ones in the southern coast, is carved in Jurassic plutonic rocks.We have collected over 6 months microseimic data, providing information on seismic activity and underground geometry of the Laguna Verde fault. We collected ca. 100 systematic measurements of fringes at the base of paleo coastal scarps through field mapping and a 5 m digital elevation model. These fringes mark the maximum sea level during the terrace's carving.The heights of these fringes range between 0 and 250 masl. We estimate a 0.7 mm/yr slip rate for the Laguna Verde fault based on the height difference between corresponding terraces north- and southward, with an average uplift rate of 0.3 mm/yr for the whole area.NW striking normal faults, besides representing a potential seismic threat to the near population on one of the most densely populated areas of Chile, heavily controls the spatial variation of the coastal margin uplift. In Laguna Verde, the uplift rate differs more than three times northward

  7. Paleohydrology of Late Quaternary floods in the Atacama Desert and their paleoclimate implications

    Science.gov (United States)

    Izquierdo, Tatiana; Abad, Manuel; Larrondo, Lidisy

    2017-04-01

    The Quaternary fluvial succession in the Copiapó Valley (northern Chile) have not been deeply studied even though they record a large amount of palaeoenvironmental and paleoclimate information in an area of great interest as the Atacama Desert. The city of Copiapó is located at the confluence between Quebrada Paipote (the most important tributary of the middle course) and Copiapó River which has been dry during the last decades due to the surface and groundwater exploitation for agricultural and mining activity purposes upstream. Despite that, historical chronicles describe numerous flooding events in the city during the last 400 years due to snowmelt during the summer months or unusually intense rains during any time of the year. The most recent event occurred on March 25, 2015 when 70% of the city flooded and more than 2.2 million m3 of sediment accumulated, mostly coming from Quebrada Paipote. The sedimentological analysis of the lower fluvial terrace of the Copiapó River has allowed us to identify a fluvial system that abruptly changes upward to paleoflood and aeolian deposits. The latter constitute the top of the lower fluvial terraces on which the city of Copiapó is built. The fluvial facies are mainly formed by imbricated to massive conglomerates and poorly sorted pebble and cobble sized conglomerates with laminated sandstones that probably were deposited in a braided gravel-bed river. The overlying deposits are constituted by several levels of massive sandy siltstones and well sorted fine sands of aeolian origin that are interpreted as overbank flood events linked to flooding episodes that alternate with long episodes of eolian dunes and sand sheets development that buried almost the entire alluvial plain. This sharp change in the facies association record an abrupt climate change in the southern Atacama Desert during the recent Quaternary towards more arid conditions, with a dominance of floods and aeolian morphogenesis over the typical fluvial system

  8. Paleochannels related to late quaternary sea-level changes in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Jair Weschenfelder

    2010-01-01

    Full Text Available The geological evolution of the continental shelf and in the coastal zone of southern Brazil during the Quaternary period is addressed in this study. High-resolution seismic records obtained at the Patos Lagoon revealed the presence of channels that deeply dissected the coastal zone before the formation of the modern, low-relief, coastal plain. Two periods of channel incision are inferred, based mainly on seismic records. The paleodrainage paths mapped from the seismic records can be connected with those recognized by previous studies on the adjacent continental shelf and slope. Upstream, the drainage incised mainly into the coastal prism deposited during previous sea-level highstand events. The paleodrainage network, recognized on the coastal plain and continental shelf, represents a river-shelf system, linking the drainage basin to the depositional settings on the marginal basin, bypassing the continental shelf exposed during a forced regression event. The drainage incised into the coastal plain and continental shelf of Rio Grande do Sul played an important role in the basin-margin architecture, facies distribution and accommodation during the Quaternary sea-level fluctuations.A evolução geológica da plataforma continental e zona costeira do sul do Brasil no período Quaternário é aqui enfocada. Registros sísmicos de alta resolução da Lagoa dos Patos revelaram canais que dissecaram profundamente a região antes da formação da planície costeira atual. Dois períodos de incisão de canal são inferidos, baseados principalmente em registros sísmicos. Os cursos fluviais mapeados por sísmica podem ser conectados àqueles reconhecidos na plataforma continental adjacente por estudos anteriores. à montante, a incisão da drenagem ocorreu principalmente no prisma sedimentar costeiro depositado durante eventos pretéritos de nível do mar alto. A rede de paleodrenagem, reconhecida na planície costeira e na plataforma continental

  9. A model of late quaternary landscape development in the Delaware Valley, New Jersey and Pennsylvania

    Science.gov (United States)

    Ridge, J.C.; Evenson, E.B.; Sevon, W.D.

    1992-01-01

    In the Delaware Valley of New Jersey and eastern Pennsylvania the late Quaternary history of colluviation, fluvial adjustment, and soil formation is based on the ages of pre-Wisconsinan soils and glacial deposits which are indicated by feld relationships and inferred from mid-latitude climate changes indicated by marine oxygen-isotope records. The area is divided into four terranes characterized by sandstone, gneiss, slate and carbonate rocks. Since the last pre-Wisconsinan glaciation (> 130 ka, inferred to be late Illinoian), each terrane responded differently to chemical and mechanical weathering. During the Sangamon interglacial stage (??? 130-75 ka) in situ weathering is inferred to have occurred at rates greater than transportation of material which resulted in the formation of deep, highly weathered soil and saprolite, and dissolution of carbonate rocks. Cold climatic conditions during the Wisconsinan, on the other hand, induced erosion of the landscape at rates faster than soil development. Upland erosion during the Wisconsinan removed pre-Wisconsinan soil and glacial sediment and bedrock to produce muddy to blocky colluvium, gre??zes lite??es, and alluvial fans on footslopes. Fluvial gravel and overlying colluvium in the Delaware Valley, both buried by late Wisconsinan outwash, are inferred to represent episodes of early and middle Wisconsinan (??? 75-25 ka) upland erosion and river aggradiation followed by river degradation and colluvium deposition. Early-middle Wisconsinan colluvium is more voluminous than later colluvium despite colder, possibly permafrost conditions during the late Wisconsinan ??? 25-10 ka). Extensive colluviation during the early and middle Wisconsinan resulted from a longer (50 kyr), generally cold interval of erosion with a greater availability of easily eroded pre-Wisconsinan surficial materials on uplands than during the late Wisconsinan. After recession of late Wisconsinan ice from its terminal position, soil formation and

  10. Evidence for alternative quaternary structure in a bacterial Type III secretion system chaperone

    Energy Technology Data Exchange (ETDEWEB)

    Barta, Michael L.; Zhang, Lingling; Picking, Wendy L.; Geisbrecht, Brian V. (UMKC); (OKLU)

    2010-10-05

    Type III secretion systems are a common virulence mechanism in many Gram-negative bacterial pathogens. These systems use a nanomachine resembling a molecular needle and syringe to provide an energized conduit for the translocation of effector proteins from the bacterial cytoplasm to the host cell cytoplasm for the benefit of the pathogen. Prior to translocation specialized chaperones maintain proper effector protein conformation. The class II chaperone, Invasion plasmid gene (Ipg) C, stabilizes two pore forming translocator proteins. IpgC exists as a functional dimer to facilitate the mutually exclusive binding of both translocators. In this study, we present the 3.3 {angstrom} crystal structure of an amino-terminally truncated form (residues 10-155, denoted IpgC10-155) of the class II chaperone IpgC from Shigella flexneri. Our structure demonstrates an alternative quaternary arrangement to that previously described for a carboxy-terminally truncated variant of IpgC (IpgC{sup 1-151}). Specifically, we observe a rotationally-symmetric 'head-to-head' dimerization interface that is far more similar to that previously described for SycD from Yersinia enterocolitica than to IpgC1-151. The IpgC structure presented here displays major differences in the amino terminal region, where extended coil-like structures are seen, as opposed to the short, ordered alpha helices and asymmetric dimerization interface seen within IpgC{sup 1-151}. Despite these differences, however, both modes of dimerization support chaperone activity, as judged by a copurification assay with a recombinant form of the translocator protein, IpaB. Conclusions: From primary to quaternary structure, these results presented here suggest that a symmetric dimerization interface is conserved across bacterial class II chaperones. In light of previous data which have described the structure and function of asymmetric dimerization, our results raise the possibility that class II chaperones may

  11. Ring-Contraction Strategy for the Practical, Scalable, Catalytic Asymmetric Synthesis of Versatile γ-Quaternary Acylcyclopentenes

    KAUST Repository

    Hong, Allen Y.

    2011-02-24

    Contraction action! A simple protocol for the catalytic asymmetric synthesis of highly functionalized γ-quaternary acylcyclopentenes (see schematic) in up to 91 % overall yield and 92 % ee has been developed. The reaction sequence employs a palladium-catalyzed enantioselective alkylation reaction and exploits the unusual stability of β-hydroxy cycloheptanones to achieve a general and robust method for performing two-carbon ring contractions.

  12. QuatIdent: a web server for identifying protein quaternary structural attribute by fusing functional domain and sequential evolution information.

    Science.gov (United States)

    Shen, Hong-Bin; Chou, Kuo-Chen

    2009-03-01

    Many proteins exist in vivo as oligomers with various different quaternary structural attributes rather than as single individual chains. They are the structural bases of various marvelous biological functions such as cooperative effects, allosteric mechanism, and ion-channel gating. Therefore, with the avalanche of protein sequences generated in the postgenomic era, it is very important for both basic research and drug discovery to identify their quaternary structural attributes in a timely manner. In view of this, a powerful ensemble identifier, called QuatIdent, is developed by fusing the functional domain and sequential evolution information. QuatIdent is a 2-layer predictor. The 1st layer is for identifying a query protein as belonging to which one of the following 10 main quaternary structural attributes: (1) monomer, (2) dimer, (3) trimer, (4) tetramer, (5) pentamer, (6) hexamer, (7) heptamer, (8) octamer, (9) decamer, and (10) dodecamer. If the result thus obtained turns out to be anything but monomer, the process will be automatically continued to further identify it as belonging to a homo-oligomer or hetero-oligomer. The overall success rate by QuatIdent for the 1st layer identification was 71.1% and that for the 2nd layer ranged from 84 to 96%. These rates were derived by the jackknife cross-validation tests on the stringent benchmark data sets where none of proteins has > or =60% pairwise sequence identity to any other in a same subset. QuatIdent is freely accessible to the public as a web server via the site at http://www.csbio.sjtu.edu.cn/bioinf/Quaternary/ , by which one can get the desired 2-level results for a query protein sequence in around 25 seconds. The longer the sequence is, the more time that is needed.

  13. The guiding center Lagrangian

    International Nuclear Information System (INIS)

    Larsson, J.

    1986-01-01

    Recursion relations determining the guiding center Langrangian Λ and the associated guiding center variables to all orders are derived. We consider some particularly simple forms of Λ obtainable by specific choices of certain arbitrary functions appearing as free parameters in the theory. It is, for example, possible to locally define the guiding center variables so that the expression for the corresponding Langrangian is unchanged by all higher order terms. (orig.)

  14. Nano-sized quaternary CuGa2In3S8 as an efficient photocatalyst for solar hydrogen production

    KAUST Repository

    Kandiel, Tarek

    2014-09-03

    The synthesis of quaternary metal sulfide (QMS) nanocrystals is challenging because of the difficulty to control their stoichiometry and phase structure. Herein, quaternary CuGa2In3S8 photocatalysts with a primary particle size of ≈4nm are synthesized using a facile hot-injection method by fine-tuning the sulfur source injection temperature and aging time. Characterization of the samples reveals that quaternary CuGa2In3S8 nanocrystals exhibit n-type semiconductor characteristics with a transition band gap of ≈1.8eV. Their flatband potential is located at -0.56V versus the standard hydrogen electrode at pH6.0 and is shifted cathodically by 0.75V in solutions with pH values greater than 12.0. Under optimized conditions, the 1.0wt% Ru-loaded CuGa2In3S8 photocatalyst exhibits a photocatalytic H2 evolution response up to 700nm and an apparent quantum efficiency of (6.9±0.5)% at 560nm. These results indicate clearly that QMS nanocrystals have great potential as nano-photocatalysts for solar H2 production. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Determination of quaternary ammonium compounds by potentiometric titration with an ionic surfactant electrode: single-laboratory validation.

    Science.gov (United States)

    Price, Randi; Wan, Ping

    2010-01-01

    A potentiometric titration for determining the quaternary ammonium compounds (QAC) commonly found in antimicrobial products was validated by a single laboratory. Traditionally, QACs were determined by using a biphasic (chloroform and water) manual titration procedure. Because of safety considerations regarding chloroform, as well as the subjectivity of color indicator-based manual titration determinations, an automatic potentiometric titration procedure was tested with quaternary nitrogen product formulations. By using the Metrohm Titrando system coupled with an ionic surfactant electrode and an Ag/AgCl reference electrode, titrations were performed with various QAC-containing formulation products/matrixes; a standard sodium lauryl sulfate solution was used as the titrant. Results for the products tested are sufficiently reproducible and accurate for the purpose of regulatory product enforcement. The robustness of the method was measured by varying pH levels, as well as by comparing buffered versus unbuffered titration systems. A quantitation range of 1-1000 ppm quaternary nitrogen was established. Eight commercially available antimicrobial products covering a variety of matrixes were assayed; the results obtained were comparable to those obtained by the manual titration method. Recoveries of 94 to 104% were obtained for spiked samples.

  16. Linking micro- and macroevolutionary perspectives to evaluate the role of Quaternary sea-level oscillations in island diversification.

    Science.gov (United States)

    Papadopoulou, Anna; Knowles, L Lacey

    2017-12-01

    With shifts in island area, isolation, and cycles of island fusion-fission, the role of Quaternary sea-level oscillations as drivers of diversification is complex and not well understood. Here, we conduct parallel comparisons of population and species divergence between two island areas of equivalent size that have been affected differently by sea-level oscillations, with the aim to understand the micro- and macroevolutionary dynamics associated with sea-level change. Using genome-wide datasets for a clade of seven Amphiacusta ground cricket species endemic to the Puerto Rico Bank (PRB), we found consistently deeper interspecific divergences and higher population differentiation across the unfragmented Western PRB, in comparison to the currently fragmented Eastern PRB that has experienced extreme changes in island area and connectivity during the Quaternary. We evaluate alternative hypotheses related to the microevolutionary processes (population splitting, extinction, and merging) that regulate the frequency of completed speciation across the PRB. Our results suggest that under certain combinations of archipelago characteristics and taxon traits, the repeated changes in island area and connectivity may create an opposite effect to the hypothesized "species pump" action of oscillating sea levels. Our study highlights how a microevolutionary perspective can complement current macroecological work on the Quaternary dynamics of island biodiversity. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  17. Degradation of Imidazolium- and Quaternary Ammonium-Functionalized Poly(fluorenyl ether ketone sulfone) Anion Exchange Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, DY; Hickner, MA

    2012-11-01

    Imidazolium and quaternary ammonium-functionalized poly(fluorenyl ether ketone sulfone)s were synthesized successfully with the same degree of cationic functionalization and identical polymer backbones for a comparative study of anion exchange membranes (AEMs) for solid-state alkaline membrane fuel cells (AMFCs). Both anion exchange membranes were synthesized using a new methyl-containing monomer that avoided the use of toxic chloromethylation reagents. The polymer chemical structures were confirmed by H-1 NMR and FTIR. The derived AEMs were fully characterized by water uptake, anion conductivity, stability under aqueous basic conditions, and thermal stability. Interestingly, both the cationic groups and the polymer backbone were found to be degraded in 1 M NaOH solution at 60 degrees C over 48 h as measured by changes of ion exchange capacity and intrinsic viscosity. Imidazolium-functionalized poly(fluorenyl ether ketone sulfone)s had similar aqueous alkaline stability to quaternary ammonium-functionalized materials at 60 degrees C but much lower stability at 80 degrees C. This work demonstrates that quaternary ammonium and imidazolium cationic groups are not stable on poly(arylene ether sulfone) backbones under relatively mild conditions. Additionally, the poly(arylene ether sulfone) backbone, which is one of the most common polymers used in ion exchange membrane applications, is not stable in the types of molecular configurations analyzed.

  18. Center for Deployment Psychology

    Data.gov (United States)

    Federal Laboratory Consortium — The Center for Deployment Psychology was developed to promote the education of psychologists and other behavioral health specialists about issues pertaining to the...

  19. Test Control Center (TCC)

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    Federal Laboratory Consortium — The Test Control Center (TCC) provides a consolidated facility for planning, coordinating, controlling, monitoring, and analyzing distributed test events. ,The TCC...

  20. Electron Microscopy Center (EMC)

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    Federal Laboratory Consortium — The Electron Microscopy Center (EMC) at Argonne National Laboratory develops and maintains unique capabilities for electron beam characterization and applies those...

  1. Audio Visual Center

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    Federal Laboratory Consortium — The Audiovisual Services Center provides still photographic documentation with laboratory support, video documentation, video editing, video duplication, photo/video...

  2. Environmental Modeling Center

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    Federal Laboratory Consortium — The Environmental Modeling Center provides the computational tools to perform geostatistical analysis, to model ground water and atmospheric releases for comparison...

  3. Great Lakes Science Center

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    Federal Laboratory Consortium — Since 1927, Great Lakes Science Center (GLSC) research has provided critical information for the sound management of Great Lakes fish populations and other important...

  4. Advanced Simulation Center

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    Federal Laboratory Consortium — The Advanced Simulation Center consists of 10 individual facilities which provide missile and submunition hardware-in-the-loop simulation capabilities. The following...

  5. Chemical Security Analysis Center

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    Federal Laboratory Consortium — In 2006, by Presidential Directive, DHS established the Chemical Security Analysis Center (CSAC) to identify and assess chemical threats and vulnerabilities in the...

  6. Small Business Development Center

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    Small Business Administration — Small Business Development Centers (SBDCs) provide assistance to small businesses and aspiring entrepreneurs throughout the United States and its territories. SBDCs...

  7. Ionic Compatibilization of Cellulose Nanocrystals with Quaternary Ammonium Salt and Their Melt Extrusion with Polypropylene.

    Science.gov (United States)

    Nagalakshmaiah, Malladi; El Kissi, Nadia; Dufresne, Alain

    2016-04-06

    On account to their high mechanical properties along with high reinforcing capacity, cellulose nanocrystals (CNCs) could be the ultimate choice for polymer nanocomposites as filler. Recently, different strategies have been investigated for the melt extrusion of CNC-based polymer nanocomposites because it is a solvent-free process and because this technique is more viable for commercial industrialization. However, most thermoplastic polymers are processed at high temperatures, and sulfuric acid preparation of CNC limits the processing because of surface sulfate groups degradation. In this study we profitably used these negatively charged groups, and quaternary ammonium salt was ionically adsorbed on CNC by a simple aqueous method. Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction were used to characterize adsorbed CNC, and changes in polarity were investigated by contact angle measurements. Modified CNC was extruded with polypropylene at 190 °C, and the ensuing composites were characterized in terms of mechanical (by dynamic mechanical analysis and tensile tests), thermal (by differential scanning calorimetry), and morphological (scanning electron microscopy) properties. The melt rheology of PP-based nanocomposites was also reported.

  8. Ether bond effects in quaternary ammonium and phosphonium ionic liquid-propanol solutions

    Science.gov (United States)

    Kishimura, Hiroaki; Kohki, Erica; Nakada, Ayumu; Tamatani, Kentaro; Abe, Hiroshi

    2018-03-01

    The liquid-liquid equilibria (LLE) of quaternary ammonium and phosphonium ionic liquid (IL)-propanol solutions were examined. The ILs contained cations with or without ether bonds; the anion in all the ILs was bis(trifluoromethanesulfonyl)imide (TFSI-). The cations without ether groups are tributylmethyl ammonium (N4441+), triethylpentyl phosphonium (P2225+), triethyloctyl phosphonium (P2228+), and tributylmethyl phosphonium (P4441+). The cations containing ether groups are N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium, (N122(2O1)+), triethyl(methoxymethyl) phosphonium (P222(1O1)+), and triethyl(2-methoxyethyl) phosphonium, (P222(2O1)+). Propanol isomer effect was observed to affect the LLEs, reflecting the geometrical factors and hydrophobicities of 1-propanol and 2-propanol. According to Raman spectroscopy, the TFSI- anion conformers in the mixtures were altered in the presence of ether bonds in the cations. The universal quasichemical (UNIQUAC) interaction parameters are consistent with significant factors affecting IL-propanol solutions, such as the type of cation (ammonium or phosphonium), ether bonds, TFSI- conformers, and propanol isomer effects.

  9. Applying DEM-SRTM for reconstructing a late Quaternary paleodrainage in Amazonia

    Science.gov (United States)

    Hayakawa, Ericson H.; Rossetti, Dilce F.; Valeriano, Márcio M.

    2010-08-01

    Remote sensing is a particularly invaluable tool that has helped the detection of paleomorphologies produced by river dislocation in a variety of landscapes, which has contributed in reconstructing the geological evolution of many fluvial systems. This technique might provide useful information to discuss the evolution of large fluvial systems, in special those located in areas of difficult access where the acquisition of field data is difficult. Application of remote sensing for paleodrainage characterization in densely vegetated tropical areas is scarce in the literature. This work records processing of the Digital Elevation Model (DEM) derived from the Shuttle Radar Topography Mission (SRTM), which succeeded in revealing an ancient drainage complex of the Madeira River, one of the main Amazonas tributaries, where other remote sensing products failed the detection. Analysis of this paleodrainage and of its modern counterpart within the geological framework available for this region leads to propose that activity along pre-existent faults during the latest Quaternary would have promoted the southeastward dislocation of a nearly 200 km long segment of the Madeira River. During this process, an impressive paleodrainage network was left behind, which was only able to be detected using the DEM-SRTM. Application of this technique might be of great help to the detection of paleodrainage morphologies in densely vegetated areas similar to the Amazonas lowland. The dynamics of channel migration in this and many other large scale tropical river systems might benefit from the investigation based on data derived from DEM-SRTM.

  10. Ages of subsurface stratigraphic intervals in the Quaternary of Enewetak Atoll, Marshall Islands

    Science.gov (United States)

    Szabo, B. J.; Tracey, J.I.; Goter, E.R.

    1985-01-01

    Drill cores of Enewetak Atoll, Marshall Islands, reveal six stratigraphic intervals, numbered in downward sequence, which represent vertical coral growth during Quaternary interglaciations. Radiocarbon dates indicate that the Holocene sea transgressed the emergent reef platform by about 8000 yr B.P. The reef grew rapidly upward (about 5 to 10 mm/yr) until about 6500 yr B.P. Afterward vertical growth slowed to about 0.5 mm/yr, then lateral development became dominant during the last several thousand years. The second interval is dated at 131,000 ?? 3000 yr B.P. by uranium series. This unit correlates with oxygen-isotope substage 5e and with terrace VIIa of Huon Peninsula, New Guinea, and of Main Reef-2 terrace at Atauro Island. The third interval is not dated because corals were recrystallized and it is tentatively correlated with either oxygen-isotope stages 7 or 9. The age of the fourth interval is estimated at 454,000 ?? 100,000 yr B.P. from measured 234U 238U activity ratios. This unit is correlated with either oxygen-isotope stage 9, 11, or 13. ?? 1985.

  11. Novel Quaternary Chalcogenide/Reduced Graphene Oxide-Based Asymmetric Supercapacitor with High Energy Density.

    Science.gov (United States)

    Sarkar, Samrat; Howli, Promita; Das, Biswajit; Das, Nirmalya Sankar; Samanta, Madhupriya; Das, G C; Chattopadhyay, K K

    2017-07-12

    In this work we have synthesized quaternary chalcogenide Cu 2 NiSnS 4 (QC) nanoparticles grown in situ on 2D reduced graphene oxide (rGO) for application as anode material of solid-state asymmetric supercapacitors (ASCs). Thorough characterization of the synthesized composite validates the proper phase, stoichiometry, and morphology. Detailed electrochemical study of the electrode materials and ASCs has been performed. The as-fabricated device delivers an exceptionally high areal capacitance (655.1 mF cm -2 ), which is much superior to that of commercial micro-supercapacitors. Furthermore, a remarkable volumetric capacitance of 16.38 F cm -3 is obtained at a current density of 5 mA cm -2 combined with a very high energy density of 5.68 mW h cm -3 , which is comparable to that of commercially available lithium thin film batteries. The device retains 89.2% of the initial capacitance after running for 2000 cycles, suggesting its long-term capability. Consequently, the enhanced areal and volumetric capacitances combined with decent cycle stability and impressive energy density endow the uniquely decorated QC/rGO composite material as a promising candidate in the arena of energy storage devices. Moreover, Cu 2 NiSnS 4 being a narrow band gap photovoltaic material, this work offers a novel protocol for the development of self-charging supercapacitors in the days to come.

  12. Research of small quaternary AChE inhibitors as pretreatment of OP poisoning

    International Nuclear Information System (INIS)

    Musilek, K.; Komloova, M.; Holas, O.; Opletalova, V.; Pohanka, M.; Kuca, K.

    2009-01-01

    Small quaternary AChE inhibitors are used (e.g. pyridostigmine) or scoped (e.g. SAD-128) for pretreatment against organophosphate intoxication [1]. The pretreatment is based on competitive inhibition of AChE prior to organophosphate (OP) poisoning. Consequently, the OP can not influence the inhibited AChE and is degraded by other esterases. Although various competitive inhibitors are used globally, pyridostigmine still remains the most broaden. Its side effects including gastrointestinal effects (nausea, intestinal obstruction), increased bronchial secretion, cardiac arrhythmia or cholinergic crisis are well described. Moreover, some bisquaternary competitive inhibitors (e.g. SAD-128) were used to decrease lethal effects of OP poisoning in vivo. The further studies dealing with SAD-128 showed its increased ability to interact with brain muscarinic acetylcholine receptors as allosteric inhibitors [2]. The small molecules derived from quaternized pyridine, quinoline and isoquinoline were designed as AChE inhibitors. Their ability to inhibit AChE or BChE was determined in vitro using IC50. The IC50 data were compared within each group of compounds with emphasis on selectivity AChE versus BChE. The overall study will be presented. The work was supported by Ministry of Defence of Czech Republic No. OVUOFVZ200805.(author)

  13. Quaternary structure of a G-protein-coupled receptor heterotetramer in complex with Gi and Gs.

    Science.gov (United States)

    Navarro, Gemma; Cordomí, Arnau; Zelman-Femiak, Monika; Brugarolas, Marc; Moreno, Estefania; Aguinaga, David; Perez-Benito, Laura; Cortés, Antoni; Casadó, Vicent; Mallol, Josefa; Canela, Enric I; Lluís, Carme; Pardo, Leonardo; García-Sáez, Ana J; McCormick, Peter J; Franco, Rafael

    2016-04-05

    G-protein-coupled receptors (GPCRs), in the form of monomers or homodimers that bind heterotrimeric G proteins, are fundamental in the transfer of extracellular stimuli to intracellular signaling pathways. Different GPCRs may also interact to form heteromers that are novel signaling units. Despite the exponential growth in the number of solved GPCR crystal structures, the structural properties of heteromers remain unknown. We used single-particle tracking experiments in cells expressing functional adenosine A1-A2A receptors fused to fluorescent proteins to show the loss of Brownian movement of the A1 receptor in the presence of the A2A receptor, and a preponderance of cell surface 2:2 receptor heteromers (dimer of dimers). Using computer modeling, aided by bioluminescence resonance energy transfer assays to monitor receptor homomerization and heteromerization and G-protein coupling, we predict the interacting interfaces and propose a quaternary structure of the GPCR tetramer in complex with two G proteins. The combination of results points to a molecular architecture formed by a rhombus-shaped heterotetramer, which is bound to two different interacting heterotrimeric G proteins (Gi and Gs). These novel results constitute an important advance in understanding the molecular intricacies involved in GPCR function.

  14. Effect of Quaternary Ammonium Salts with Fluorine Atoms on Selected Weed Species.

    Science.gov (United States)

    Biczak, Robert; Pawłowska, Barbara; Płatkowski, Maciej; Stręk, Michał; Telesiński, Arkadiusz

    2017-04-01

    This study investigated the effects of four structurally different quaternary ammonium salts (QASs), i.e., tetrabutylammonium tetrafluoroborate [TBA][BF 4 ], tetrahexylammonium tetrafluoroborate [THA][BF 4 ], tetrabutylammonium hexafluorophosphate [TBA][PF 6 ], and tetrahexylammonium hexafluorophosphate [THA][PF 6 ], on the growth and development of three weed species: gallant soldier (Galinsoga parviflora Cav.), white goosefoot (Chenopodium album L.) and common sorrel (Rumex acetosa L.). The examined compounds were applied in the form of foliar spraying and soil application. Strong herbicidal properties of the examined compounds were demonstrated in case of their soil application. Growth inhibition of plant shoots and roots was greater with soil application than with foliar treatment. The strongest herbicidal activity of compounds was demonstrated with [TBA][BF 4 ] have demonstrated [TBA][BF 4 ] and [TBA][PF 6 ] applied to the soil, while [THA][BF 4 ] demonstrated the weakest herbicidal action. The increased concentration of applied QASs caused a decrease in the assimilation pigments, change in dry weight content and inhibition of length of shoots and roots.

  15. Effect of aminoacids on the fungicidal activity of quaternary ammonium salts

    Directory of Open Access Journals (Sweden)

    Jerzy Piątkowski

    2013-12-01

    Full Text Available Amphipatic compounds exhibit an antimicrobial action both on bacteria and fungi. It is caused by a penetrative property of hydrophobic carbon chain of the compuound into a plasma membrane as well as by additional interaction of membrane elements and a hydrophilic amphipathic compound head. Bactericidal and fungicidal activity of this compound strongly depends on chemical environmental factors. In general, microorganisms are not as sensitive in a full medium as in a minimal one and the level of sensitivity rises when the amphipatic compounds are presend in destilled water. Similarly, the sensitivity is stronger in fluid than on solid medium. Our researches revealed however that some aminoacids, although they are complex organic compounds, increase the microbial sensitivity to some tested compound. This efect depends on a microorganism and on a kind of compound. The highest hipersensitivity has been observed against yeast-like fungi when arginine was a cooperating aminoacid. The effect concerns Trichosporon but not E.coli, not occurs in relation to SDS, quaternary ammonium salt IA, and bisammonium salts. Certainly the effect exhibit QAS, which have simple composition of hydrophilic „head” consisting only of methyl group, attaching to alkilic chain possessing keton group, build of 14 or 16 carbon atoms.

  16. Geomorphological evidences of Quaternary tectonic activities in the Santa Cruz river valley, Patagonia, Argentina

    International Nuclear Information System (INIS)

    Massabie, A.; Sanguinetti, A.; Nestiero, O.

    2007-01-01

    From Argentin lake, at west on Andean hills, to Puerto Santa Cruz on Atlantic coast, Santa Cruz river cross eastward Santa Cruz province over 250 km in Patagonia at southern Argentina. Present bed of the river has a meandering outline with first order meanders of great ratio bends and second order meanders of minor ratio bends. Principal wanderings are 45 to 55 km spaced from near Estancia La Julia or Rio Bote at west to Comandante Luis Piedrabuena at east. On river's bed middle sector these great curvatures are located at Estancia Condor Cliff and Estancia Rincon Grande. Regional and partial detailed studies allow to recognize structural control on river's bed sketch and valley s geomorphology that relates first order bends with reactivated principal faults. These faults fit well with parallel system of northwest strike of Austral Basin.On geological, geomorphologic and structural evidences recognized in Santa Cruz river, quaternary tectonic activity, related to Andean movements in southern Patagonian foreland, is postulated. (author)

  17. Investigation of melamine derived quaternary as ammonium salt potential shale inhibitor

    Science.gov (United States)

    Yu, Hongjiang; Hu, Weimin; Guo, Gang; Huang, Lei; Li, Lili; Gu, Xuefan; Zhang, Zhifang; Zhang, Jie; Chen, Gang

    2017-06-01

    Melamine, sodium chloroacetate and sodium hydroxide were used as raw materials to synthesize a kind of neutral quaternary ammonium salt (NQAS) as potential clay swelling inhibitor and water-based drilling fluid additive, and the reaction conditions were screened based on the linear expansion rate of bentonite. The inhibitive properties of NQASs were investigated by various methods, including montmorillonite (MMT) linear expansion test, mud ball immersing test, particle distribution measurement, thermogravimetric analysis and scanning electron microscopy etc. The results indicate that NQAS can inhibit expansion and dispersion of clay in water effectively. At the same condition, the bentonite linear expansion rate in NQAS-6 solution is much lower than those of others, and the hydration expansion degree of the mud ball in 0.5% NQAS-6 solution is appreciably weaker than the control test. The compatibility test indicates NQAS-6 could be compatible with the conventional additives in water-based drilling fluids, and the temperature resistance of modified starch was improved effectively. Meanwhile, the inhibitive mechanism was discussed through the particle distribution measurement.

  18. Earthquake response characteristics of large structure 'JOYO' deeply embedded in quaternary ground, (3)

    International Nuclear Information System (INIS)

    Yajima, Hiroshi; Sawada, Yoshihiro; Hanada, Kazutake; Sawada, Makoto.

    1987-01-01

    In order to examine aseismicity of embedded structure and to clarify embedment effect, earthquake observations of the large structure 'JOYO' are carried out which is deeply embedded in quaternary ground, and the results are summarized as follows. (1) Amplification factors of horizontal component in ground surface is about 3 to 4 times against the bedrock. Contrastively on the structure, any amplification is not observed at the underground portion, however, little amplification exists at the ground portion of structure. (2) Transfer function of structure has several predominant peaks at frequencies of 4.3 Hz and 8.0 Hz which are well coincided with values obtained from force excitation tests. It is shown that transfer function between basement and ground surface is similar to that between ground of same level to basement and ground surface, suggesting the behavior of basement to be able to estimate by these under ground earthquake motion. (3) According to earthquake motion analysis using S-R models, without regard to consider or not the side ground stiffness, the calculated response values do not so much differ in each model and mostly correspond with observation data, provided that the underground earthquake motion at same level to basement is used as a input wave. Consequently, the behavior of these deeply embedded structure is subject to setting method of input wave rather than modeling method, and it is very useful in design that the most simple model without side ground stiffness can roughly represent the embedment effect. (author)

  19. Photoluminescent nano-sized ternary and quaternary complexes of thorium(IV)

    International Nuclear Information System (INIS)

    Baranwal, B.P.; Jain, A.K.; Varma, A.; Singh, A.K.; Fatma, T.

    2011-01-01

    Some ternary and quaternary complexes of thorium(IV) with the general formula [Th(OOCCH 3 ) 2-n (SB) n (OOCC 15 H 31 ) 2 ] (HSB=Schiff bases and n=1 or 2) have been synthesized by the stepwise substitutions of acetate ions from thorium(IV) acetate, first with straight chain carboxylic acid and then with Schiff bases. The complexes are characterized by elemental analyses, spectral (electronic, infrared, 1 H NMR, FAB mass, photoluminescence and powder XRD) and TEM studies. Conductance measurements indicated non-conducting behaviour of the complexes. Structural parameters from powder XRD data for complexes 5 and 6 which indicate poorly crystalline nano-sized triclinic particles. Electronic absorption spectra of the complexes showed π → π * and n → π * charge transfer transitions. All complexes displayed fluorescence and a correlation was sought between luminescence spectra of complexes in solution at room temperature. On the basis of physico-chemical studies, coordination number 8 was assigned for thorium(IV) in the complexes. The morphology and microstructure of the complexes were examined with transmission electron microscopy (TEM) and the selected area electron diffraction (SAED). (orig.)

  20. Sputtered tungsten-based ternary and quaternary layers for nanocrystalline diamond deposition.

    Science.gov (United States)

    Walock, Michael J; Rahil, Issam; Zou, Yujiao; Imhoff, Luc; Catledge, Shane A; Nouveau, Corinne; Stanishevsky, Andrei V

    2012-06-01

    Many of today's demanding applications require thin-film coatings with high hardness, toughness, and thermal stability. In many cases, coating thickness in the range 2-20 microm and low surface roughness are required. Diamond films meet many of the stated requirements, but their crystalline nature leads to a high surface roughness. Nanocrystalline diamond offers a smoother surface, but significant surface modification of the substrate is necessary for successful nanocrystalline diamond deposition and adhesion. A hybrid hard and tough material may be required for either the desired applications, or as a basis for nanocrystalline diamond film growth. One possibility is a composite system based on carbides or nitrides. Many binary carbides and nitrides offer one or more mentioned properties. By combining these binary compounds in a ternary or quaternary nanocrystalline system, we can tailor the material for a desired combination of properties. Here, we describe the results on the structural and mechanical properties of the coating systems composed of tungsten-chromium-carbide and/or nitride. These WC-Cr-(N) coatings are deposited using magnetron sputtering. The growth of adherent nanocrystalline diamond films by microwave plasma chemical vapor deposition has been demonstrated on these coatings. The WC-Cr-(N) and WC-Cr-(N)-NCD coatings are characterized with atomic force microscopy and SEM, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and nanoindentation.

  1. Shifting sources and transport paths for the late Quaternary Escanaba Trough sediment fill (northeast Pacific)

    Science.gov (United States)

    Zuffa, G.G.; De Rosa, R.; Normark, W.R.

    1997-01-01

    Escanaba Trough, which forms the southernmost part of the axial valley of the actively spreading Gorda Ridge, is filled with several hundred meters of sediment of presumed late Quaternary age. Surficial sediment samples from gravity cores, deeper samples (as much as 390 m) from Site 35 of the Deep Sea Drilling Program (Leg 5), and the acoustic character of the sediment fill observed on seismic-reflection profiles indicate that much of the sediment fill is of turbidite origin. Gross composition and heavy- mineral analyses of sand samples show that two distinct petrofacies comprise the sediment fill. The lower part of the fill was derived primarily from the Klamath River source of northern California while the younger fill, including the surficial sand beds, are from the Columbia River drainage much farther north. The Escanaba Trough sediment provides an opportunity to evaluate concepts for paleogeographic and paleotectonic reconstructions that are based on facies analysis and compositional and textural data for the volcanic components because both intrabasinal and extrabasinal sources are present as well as coeval (neovolcanic) and non coeval (paleovolcanic) sourcre This study of a modern basin shows, that although the sediment sources could be identified, it was useful to have some knowledge of the sediment pathway(s), the effects of diagenesis, and the possible effects of sediment sorting as a result of long transport distances from the source area for some components. Application of these same techniques to ancient deposits without benefit of the additional parameters will face limitations.

  2. Inhibition of biofouling by modification of forward osmosis membrane using quaternary ammonium cation.

    Science.gov (United States)

    Park, Kang-Hee; Yu, Sang-Hyun; Kim, Han-Shin; Park, Hee-Deung

    2015-01-01

    In the operation of the forward osmosis (FO) process, biofouling of the membrane is a potentially serious problem. Development of an FO membrane with antibacterial properties could contribute to a reduction in biofouling. In this study, quaternary ammonium cation (QAC), a widely used biocidal material, was conjugated with a silane coupling agent (3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride) and used to modify an FO membrane to confer antibacterial properties. Fourier transform infrared spectroscopy (FT-IR) demonstrated that the conjugated QAC was successfully immobilized on the FO membrane via covalent bonding. Bacterial viability on the QAC-modified membrane was confirmed via colony count method and visualized via bacterial viability assay. The QAC membrane decreased the viability of Escherichia coli to 62% and Staphylococcus aureus to 77% versus the control membrane. Inhibition of biofilm formation on the QAC modified membrane was confirmed via anti-biofilm tests using the drip-flow reactor and FO unit, resulting in 64% and 68% inhibition in the QAC-modified membrane against the control membrane, respectively. The results demonstrate the effectiveness of the modified membrane in reducing bacterial viability and inhibiting biofilm formation, indicating the potential of QAC-modified membranes to decrease operation costs incurred by biofouling.

  3. Petrography and petrology of Quaternary volcanic rocks from Ghezel Ghaleh, northwest Qorveh

    Directory of Open Access Journals (Sweden)

    Alireza Bajelan

    2014-10-01

    Full Text Available Introduction In the east and northeast of Sanandaj in the Qorveh-Bijar-Takab axis, there are series of basaltic composition volcanoes with Quaternary age. The study area is part of the Sanandaj-Sirjan zone and is located between 47°52' and 47°57' E longitudes and 35°26 and '35°30' N latitudes. Due to the location of the volcanic cone on Pliocene clastic sediments and Quaternary travertine, the age of these volcanoes is considered to be Quaternary. The cones mostly consist of low scoria, ash, volcanic bombs, lapilli deposits and basaltic lava (Moein Vaziri and Aminsobhani, 1985. Petrological and geochemical studies have been carried out to evaluate Quaternary magmatism in the area and to determine the nature of the lithological characteristics, such as the evaluation of source rocks and magma type, degree of partial melting and the tectonic setting of Ghezel Ghaleh rocks (Moein Vaziri, 1997. Simplified geological map of the study area is characterized by ER-Mapper software. Materials and methods In the course of field studies in the region, 40 samples were taken, 30 thin sections were prepared and polished. XRD analyses were performed on some whole rock samples. All major, minor and trace elements were assessed by ICP-MS at Lab Weft Laboratory in Australia. Results Based on the classification of structural zones, the area is located in the Sanandaj-Sirjan zone, hundred kilometers away from the main Zagros thrust along the NW-SE direction. After early Cimmerian orogeny, andesitic volcanic activity took place (Moein Vaziri and Aminsobhani, 1985. A major secondary mineral in these rocks is iddingsite, formed by hydration and oxidation of the olivine (Shelley, 1993. According to SiO2 against Na2O + K2O (TAS diagram (Irvine and Baragar , 1971 and cationic R1 and R2 diagram (De La Roche et el., 1980, volcanic rocks of the area indicate alkaline series. Discussion To obtain more information on the tectonic setting of these rocks, the Zr/Y-Zr diagram

  4. Taxonomy of quaternary deep-sea ostracods from the Western North Atlantic ocean

    Science.gov (United States)

    Yasuhara, Moriaki; Okahashi, H.; Cronin, T. M.

    2009-01-01

    Late Quaternary sediments from Ocean Drilling Program (ODP) Hole 1055B, Carolina Slope, western North Atlantic (32??47.041??? N, 76??17.179??? W; 1798m water depth) were examined for deep-sea ostracod taxonomy. A total of 13933 specimens were picked from 207 samples and c. 120 species were identified. Among them, 87 species were included and illustrated in this paper. Twenty-eight new species are described. The new species are: Ambocythere sturgio, Argilloecia abba, Argilloecia caju, Argilloecia keigwini, Argilloecia robinwhatleyi, Aversovalva carolinensis, Bythoceratina willemvandenboldi, Bythocythere eugeneschornikovi, Chejudocythere tenuis, Cytheropteron aielloi, Cytheropteron demenocali, Cytheropteron didieae, Cytheropteron richarddinglei, Cytheropteron fugu, Cytheropteron guerneti, Cytheropteron richardbensoni, Eucytherura hazeli, Eucytherura mayressi, Eucytherura namericana, Eucytherura spinicorona, Posacythere hunti, Paracytherois bondi, Pedicythere atroposopetasi, Pedicythere kennettopetasi, Pedicythere klothopetasi, Pedicythere lachesisopetasi, Ruggieriella mcmanusi and Xestoleberis oppoae. Taxonomic revisions of several common species were made to reduce taxonomic uncertainty in the literature. This study provides a robust taxonomic baseline for application to palaeoceanographical reconstruction and biodiversity analyses in the deep and intermediate-depth environments of the North Atlantic Ocean. ?? The Palaeontological Association, 2009.

  5. Coming to Grips with Ambiguity: Ion Mobility-Mass Spectrometry for Protein Quaternary Structure Assignment

    Science.gov (United States)

    Eschweiler, Joseph D.; Frank, Aaron T.; Ruotolo, Brandon T.

    2017-10-01

    Multiprotein complexes are central to our understanding of cellular biology, as they play critical roles in nearly every biological process. Despite many impressive advances associated with structural characterization techniques, large and highly-dynamic protein complexes are too often refractory to analysis by conventional, high-resolution approaches. To fill this gap, ion mobility-mass spectrometry (IM-MS) methods have emerged as a promising approach for characterizing the structures of challenging assemblies due in large part to the ability of these methods to characterize the composition, connectivity, and topology of large, labile complexes. In this Critical Insight, we present a series of bioinformatics studies aimed at assessing the information content of IM-MS datasets for building models of multiprotein structure. Our computational data highlights the limits of current coarse-graining approaches, and compelled us to develop an improved workflow for multiprotein topology modeling, which we benchmark against a subset of the multiprotein complexes within the PDB. This improved workflow has allowed us to ascertain both the minimal experimental restraint sets required for generation of high-confidence multiprotein topologies, and quantify the ambiguity in models where insufficient IM-MS information is available. We conclude by projecting the future of IM-MS in the context of protein quaternary structure assignment, where we predict that a more complete knowledge of the ultimate information content and ambiguity within such models will undoubtedly lead to applications for a broader array of challenging biomolecular assemblies. [Figure not available: see fulltext.

  6. Tropical Rain Forest and Climate Dynamics of the Atlantic Lowland, Southern Brazil, during the Late Quaternary

    Science.gov (United States)

    Behling, Hermann; Negrelle, Raquel R. B.

    2001-11-01

    Palynological analysis of a core from the Atlantic rain forest region in Brazil provides unprecedented insight into late Quaternary vegetational and climate dynamics within this southern tropical lowland. The 576-cm-long sediment core is from a former beach-ridge "valley," located 3 km inland from the Atlantic Ocean. Radio-carbon dates suggest that sediment deposition began prior to 35,000 14C yr B.P. Between ca. 37,500 and ca. 27,500 14C yr B.P. and during the last glacial maximum (LGM; ca. 27,500 to ca. 14,500 14C yr B.P.), the coastal rain forest was replaced by grassland and patches of cold-adapted forest. Tropical trees, such as Alchornea, Moraceae/Urticaceae, and Arecaceae, were almost completely absent during the LGM. Furthermore, their distributions were shifted at least 750 km further north, suggesting a cooling between 3°C and 7°C and a strengthening of Antarctic cold fronts during full-glacial times. A depauperate tropical rain forest developed as part of a successional sequence after ca. 12,300 14C yr B.P. There is no evidence that Araucaria trees occurred in the Atlantic lowland during glacial times. The rain forest was disturbed by marine incursions during the early Holocene period until ca. 6100 14C yr B.P., as indicated by the presence of microforaminifera. A closed Atlantic rain forest then developed at the study site.

  7. Differential effects of temperature change and human impact on European Late Quaternary mammalian extinctions.

    Science.gov (United States)

    Varela, Sara; Lima-Ribeiro, Matheus Souza; Diniz-Filho, José Alexandre Felizola; Storch, David

    2015-04-01

    Species that inhabited Europe during the Late Quaternary were impacted by temperature changes and early humans, resulting in the disappearance of half of the European large mammals. However, quantifying the relative importance that each factor had in the extinction risk of species has been challenging, mostly due to the spatio-temporal biases of fossil records, which complicate the calibration of realistic and accurate ecological niche modeling. Here, we overcome this problem by using ecotypes, and not real species, to run our models. We created 40 ecotypes with different temperature requirements (mean temperature from -20 °C to 25 °C and temperature range from 10 °C to 40 °C) and used them to quantify the effect of climate change and human impact. Our results show that cold-adapted ecotypes would have been highly affected by past temperature changes in Europe, whereas temperate and warm-adapted ecotypes would have been positively affected by temperature change. Human impact affected all ecotypes negatively, and temperate ecotypes suffered the greatest impacts. Based on these results, the extinction of cold-adapted species like Mammuthus primigenius may be related to temperature change, while the extinction of temperate species, like Crocuta crocuta, may be related to human impact. Our results suggest that temperature change and human impact affected different ecotypes in distinct ways, and that the interaction of both impacts may have shaped species extinctions in Europe. © 2014 John Wiley & Sons Ltd.

  8. Emergence of resistance to antibacterial agents: the role of quaternary ammonium compounds--a critical review.

    Science.gov (United States)

    Buffet-Bataillon, Sylvie; Tattevin, Pierre; Bonnaure-Mallet, Martine; Jolivet-Gougeon, Anne

    2012-05-01

    Quaternary ammonium compounds (QACs) are widely distributed in hospitals, industry and cosmetics. Little attention has been focused on the potential impact of QACs on the emergence of antibiotic resistance in patients and the environment. To assess this issue, we conducted a literature review on QAC chemical structure, fields of application, mechanism of action, susceptibility testing, prevalence, and co- or cross-resistance to antibiotics. Special attention was paid to the effects of QACs on microflora; in particular, the issue of the potential of QACs for applying selective pressure on multiple-antibiotic-resistant organisms was raised. It was found that there is a lack of standardised procedures for interpreting susceptibility test results. QACs have different impacts on the minimum inhibitory concentrations of antibacterials depending on the antibacterial compound investigated, the resistance genes involved, the measuring methodology and the interpretative criteria. The unmet needs for adequate detection of reduced susceptibility to QACs and antibiotics include (i) a consensus definition for resistance, (ii) epidemiological cut-off values and (iii) clinical resistance breakpoints. This review advocates the design of international guidelines for QAC use. Copyright © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  9. Antimicrobial activity of a quaternary ammonium methacryloxy silicate-containing acrylic resin: a randomised clinical trial.

    Science.gov (United States)

    Liu, Si-ying; Tonggu, Lige; Niu, Li-na; Gong, Shi-qiang; Fan, Bing; Wang, Liguo; Zhao, Ji-hong; Huang, Cui; Pashley, David H; Tay, Franklin R

    2016-02-23

    Quaternary ammonium methacryloxy silicate (QAMS)-containing acrylic resin demonstrated contact-killing antimicrobial ability in vitro after three months of water storage. The objective of the present double-blind randomised clinical trial was to determine the in vivo antimicrobial efficacy of QAMS-containing orthodontic acrylic by using custom-made removable retainers that were worn intraorally by 32 human subjects to create 48-hour multi-species plaque biofilms, using a split-mouth study design. Two control QAMS-free acrylic disks were inserted into the wells on one side of an orthodontic retainer, and two experimental QAMS-containing acrylic disks were inserted into the wells on the other side of the same retainer. After 48 hours, the disks were retrieved and examined for microbial vitality using confocal laser scanning microscopy. No harm to the oral mucosa or systemic health occurred. In the absence of carry-across effect and allocation bias (disks inserted in the left or right side of retainer), significant difference was identified between the percentage kill in the biovolume of QAMS-free control disks (3.73 ± 2.11%) and QAMS-containing experimental disks (33.94 ± 23.88%) retrieved from the subjects (P ≤ 0.001). The results validated that the QAMS-containing acrylic exhibits favourable antimicrobial activity against plaque biofilms in vivo. The QAMS-containing acrylic may also be used for fabricating removable acrylic dentures.

  10. Kinetic and thermodynamic studies on the adsorption of anionic surfactant on quaternary ammonium cationic cellulose.

    Science.gov (United States)

    Zhang, Yuanzhang; Shi, Wenjian; Zhou, Hualan; Fu, Xing; Chen, Xuan

    2010-06-01

    Removal of anionic surfactants from aqueous solutions by adsorption onto quaternary ammonium cationic cellulose (QACC) was investigated. The effects of solution acidity, initial concentration, adsorption time, and temperature on the adsorption of sodium dodecyl-benzene sulfonate (SDBS), sodium lauryl sulfate (SLS), and sodium dodecyl sulfonate (SDS) were studied. The kinetic experimental data fit well with the pseudo-second-order model; the rate constant of the adsorption increased with temperature. The values of apparent activation energy for the adsorption were calculated as ranging from 10.2 to 17.4 kJ/ mol. The adsorption isotherm can be described by the Langmuir isotherm. The values of thermodynamic parameters (deltaH0, deltaS0, and deltaG0) for the adsorption indicated that this process was spontaneous and endothermic. At 318 K, the saturated adsorption capacities of QACC for SDBS, SLS, and SDS were 1.75, 1.53, and 1.39 mmol/g, respectively. The adsorption process was mainly chemisorption and partially physisorption. The results show that QACC is effective for the removal of anionic surfactants.

  11. Study on quaternary stratigraphy and environmental changes in South Sea, Korea

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Jeong-Hae; Lee, Chi-Won; Kim, Sung-Pil [Korea Institute of Geology Mining and Materials, Taejon (KR)] (and others)

    1999-12-01

    According to interpretation of seismic profiles crossing the drilled sites, there are five sequences, namely Unit I, Unit II, Unit III, Unit IV and Unit V from bottom, separable by a reflector with good lateral continuity. If we apply the conception of sequential stratigraphy to the sea level fluctuation caused depositional processes, based on the results of seismic profiles, it will be possible to figure out the late Quaternary depositional processes in the context of sea level changes. According to the sedimentological and seismic stratigraphic analysis, most of SSDP sites showed transgression and regression sequences. Chemical analyses of elements for the sediment samples of SSDP-102 core exhibit the geochemical factors which may influenced the sedimentary environments of the study area. The lower-most sedimentary sequence Unit III can be interpreted as an environment which was influenced dominantly by stronger chemical weathering under a semi-fresh water environment. Based on predominance of carbonate-originated Ca in the homogeneous mud sequence, a high productive surface water along with transgression may have controlled the upper-most sedimentary sequence Unit I. Scatter diagram represents oxygen and carbon isotopic values of benthic foraminifera (Asterorotalia concinna) which is analyzed. All 61 points has value between +1 and -1. If isotopic values of selected benthic foraminifera are equilibrium with surrounding values. These distributions indicate transitional between coastal environment affected by fresh water and open marine environment. (author). 24 refs., 8 tabs., 25 figs.

  12. Chemical, biochemical, and microbiological aspects of chitosan quaternary salt as active coating on sliced apples

    Directory of Open Access Journals (Sweden)

    Douglas de Britto

    2012-09-01

    Full Text Available The biocompatibility of chitosan and chitosan quaternary salt coatings was evaluated for use as edible coatings for sliced apple. Measurement of water loss, color change, and fungal growth appearance were monitored as a function of time. A significant brownish effect was observed on chitosan coated slices, varying greatly from L* = 76.5 and Hue angle = 95.9° (t = 0 to L* = 45.3 and Hue angle = 69.8° (t = 3 days, whilst for TMC coated samples the variation was considerable lower (L* = 74.1; Hue angle = 95.0° to (L* = 67.0; Hue angle = 83.8° within the same period. The hydrosoluble derivative N,N,N-trimethylchitosan demonstrated good antifungal activity against P. expansum although highly dependent on the polymer properties such as degree of quaternization. The most efficient formulation was that prepared from derivative having a degree of quaternization of 45%, high solubility, and high viscosity. This formulation restrained fungus spreading up to 30%, while for the control it reached almost 80% of the total assessed surfaces during 7 days of storage.

  13. Anti-Caries Effects of Dental Adhesives Containing Quaternary Ammonium Methacrylates with Different Chain Lengths

    Directory of Open Access Journals (Sweden)

    Qi Han

    2017-06-01

    Full Text Available The objectives of this study were to investigate the effects of dental adhesives containing quaternary ammonium methacrylates (QAMs with different alkyl chain lengths (CL on ecological caries prevention in vitro. Five QAMs were synthesized with a CL = 3, 6, 9, 12, and 16 and incorporated into adhesives. Micro-tensile bond strength and surface charge density were used to measure the physical properties of the adhesives. The proportion change in three-species biofilms consisting of Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii was tested using the TaqMan real-time polymerase chain reaction. Lactic acid assay, MTT [3-(4,5-dimethyl-thiazol-2-yl-2,5-diphenyltetrazolium bromide] assay, exopolysaccharide staining, live/dead staining, scanning electron microscopy (SEM, and transverse microradiography (TMR were performed to study the anti-biofilm and anti-demineralization effects of the dental adhesives. The results showed that incorporating QAMs with different alkyl chain lengths into the adhesives had no obvious effect on the dentin bond strength. The adhesives containing QAMs with a longer alkyl chain developed healthier biofilms. The surface charge density, anti-biofilm, and anti-demineralization effects of the adhesives increased with a CL of the QAMs from 3 to 12, but decreased slightly with a CL from 12 to 16. In conclusion, adhesives containing QAMs with a tailored chain length are promising for preventing secondary caries in an “ecological way”.

  14. Synthesis, physiochemical property and antimicrobial activity of novel quaternary ammonium salts.

    Science.gov (United States)

    Xie, Xianrui; Cong, Wei; Zhao, Feng; Li, Hongjuan; Xin, Wenyu; Hou, Guige; Wang, Chunhua

    2018-12-01

    Twenty-four novel 5-phenyl-1,3,4-oxadiazole-2-thiol (POT) analogues, benzo[d]oxazole-2-thiol, benzo[d]thiazole-2-thiol and 5-methyl-1,3,4-thiadiazole-2-thiol-substituted N,N-bis(2-hydroxyethyl) quaternary ammonium salts (QAS) (5a-d, 6a-d, 7a-d, 10a-d, 13a-d, 16a-d) were prepared and characterised by FTIR, NMR and elemental analysis. Part of target compounds (5d, 6d, 7d, 10d, 13d, 16d) displayed potent antimicrobial effect against ten common pathogens (S. aureus, α-H-tococcus, β-H-tococcus, E. coli, P. aeruginosa, Proteus vulgaris, Canidia Albicans, Cytospora mandshurica, Physalospora piricola, Aspergillus niger) and had relatively low cytotoxity against two human cell lines (HaCat and LO2). TEM and SEM images of E. coli and S. aureus morphologies treated with 7d showed that the antibacterial mechanism might be the QAS fixing on cell wall surfaces and puncturing to result in the release of bacterial cytoplasm. This study provides new information of QAS, which could be used to design novel antimicrobial agents applied in clinic or agriculture.

  15. Quaternary chronostratigraphy and stable isotope paleoecology of Big Bone Lick, Kentucky, USA

    Science.gov (United States)

    Tankersley, Kenneth Barnett; Murari, Madhav Krishna; Crowley, Brooke E.; Owen, Lewis A.; Storrs, Glenn W.; Mortensen, Litsa

    2015-05-01

    Big Bone Lick (BBL) in northern Kentucky, USA has been a critical geologic site in the historical development of North American Quaternary vertebrate paleontology since the 1700s. Sedimentology, geoarcheology, paleontology, accelerator mass spectrometry radiocarbon and optically stimulated luminescence dating, and stable carbon and nitrogen isotope analyses were undertaken to develop a chronostratigraphy and history of erosion and deposition for the site to provide a foundation for understanding taphonomy, and species extinction and adaptation to periods of climatic and environmental change. Three geomorphic surfaces are recognized at BBL representing significant periods of floodplain aggradation since the last glacial maximum (26.5-19 ka) dating to the Oldest Dryas (Tazewell, 25-19 ka), the Older Dryas (Cary, 14-12 ka), and late Holocene (5 ka to the present). Unconformities suggest significant periods of degradation during the transitions from cold and dry to warm and moist climates from the Oldest Dryas (Tazewell) to Bølling Oscillation, from the Older Dryas (Cary) to the Allerød, and from the Younger Dryas (Valders) to the Holocene Climatic Optimum. Increased anthropogenic activities since 5 ka may have increased soil upland erosion and floodplain aggradation. Stable isotopes demonstrate that the landscape has been dominated by C3 vegetation since the last glacial maximum.

  16. Quaternary dating by electron spin resonance (ESR applied to human tooth enamel

    Directory of Open Access Journals (Sweden)

    Carvajal Eduar

    2011-12-01

    Full Text Available This paper presents the results obtained from using electron paramagnetic resonance (EPR to analyse tooth enamel found at the Aguazuque archaeological site (Cundinamarca, Colombia, located on the savannah near Bogota at 4° 37' North and 74°17' West. It was presumed that the tooth enamel came from a collective burial consisting of 23 people, involving men, women and children. The tooth enamel was irradiated with gamma rays and the resulting free radicals were measured using an electron spin resonance (ESR X-band spectrometer to obtain a signal intensity compared to absorbed doses curve. Fitting this curve allowed the mean archaeological dose accumulated in the enamel during the period that it was buried to be estimated, giving a 2.10 ± 0.14 Gyvalue. ROSY software was used for estimating age, giving a mean 3,256 ± 190y before present (BP age. These results highlight EPR's potential when using the quaternary ancient ruins dating technique in Colombia and its use with other kinds of samples like stalagmites, calcite, mollusc shells and reefs.

  17. Multifunctional properties related to magnetostructural transitions in ternary and quaternary Heusler alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dubenko, Igor, E-mail: igor_doubenko@yahoo.com [Department of Physics, Southern Illinois University, Carbondale, IL 62901 (United States); Quetz, Abdiel; Pandey, Sudip; Aryal, Anil; Eubank, Michael [Department of Physics, Southern Illinois University, Carbondale, IL 62901 (United States); Rodionov, Igor; Prudnikov, Valerii; Granovsky, Alexander [Faculty of Physics, Moscow State University, Vorob' evy Gory, 11999I Moscow (Russian Federation); Lahderanta, Erkki [Lappeenranta University of Technology, 53851 (Finland); Samanta, Tapas; Saleheen, Ahmad; Stadler, Shane [Department of Physics & Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Ali, Naushad [Department of Physics, Southern Illinois University, Carbondale, IL 62901 (United States)

    2015-06-01

    In this report, the results of a study on the effects of compositional variations induced by the small changes in concentrations of the parent components and/or by the substitution of Ni, Mn, or In by an extra element Z, on the phase transitions, and phenomena related to the magnetostructural transitions in off-stoichiometric Ni–Mn–In based Heusler alloys are summarized. The crystal structures, phase transitions temperatures, and magnetic and magnetocaloric properties were analyzed for representative samples of the following systems (all near 15 at% indium concentration): Ni–Mn–In, Ni–Mn–In–Si, Ni–Mn–In–B, Ni–Mn–In–Cu, Ni–Mn–In–Cu–B, Ni–Mn–In–Fe, Ni–Mn–In–Ag, and Ni–Mn–In–Al. - Highlights: • The experimental results on phase transitions temperatures, adiabatic temperature changes, magnetoresistance and heat flow for the ternary and quaternary Heusler alloys based on Ni{sub 50}Mn{sub 35}In{sub 15} demonstrate high sensitivity of magnetic properties to the small changes in concentrations of the parent components and/or by the substitution of Ni, Mn, or In by an additional element Z. • The phenomena related to the magnetostructural transitions strongly depend on the weighted average radius of constituent ions.

  18. Species-specific responses of Late Quaternary megafauna to climate and humans

    Science.gov (United States)

    Lorenzen, Eline D.; Nogués-Bravo, David; Orlando, Ludovic; Weinstock, Jaco; Binladen, Jonas; Marske, Katharine A.; Ugan, Andrew; Borregaard, Michael K.; Gilbert, M. Thomas P.; Nielsen, Rasmus; Ho, Simon Y. W.; Goebel, Ted; Graf, Kelly E.; Byers, David; Stenderup, Jesper T.; Rasmussen, Morten; Campos, Paula F.; Leonard, Jennifer A.; Koepfli, Klaus-Peter; Froese, Duane; Zazula, Grant; Stafford, Thomas W.; Aaris-Sørensen, Kim; Batra, Persaram; Haywood, Alan M.; Singarayer, Joy S.; Valdes, Paul J.; Boeskorov, Gennady; Burns, James A.; Davydov, Sergey P.; Haile, James; Jenkins, Dennis L.; Kosintsev, Pavel; Kuznetsova, Tatyana; Lai, Xulong; Martin, Larry D.; McDonald, H. Gregory; Mol, Dick; Meldgaard, Morten; Munch, Kasper; Stephan, Elisabeth; Sablin, Mikhail; Sommer, Robert S.; Sipko, Taras; Scott, Eric; Suchard, Marc A.; Tikhonov, Alexei; Willerslev, Rane; Wayne, Robert K.; Cooper, Alan; Hofreiter, Michael; Sher, Andrei; Shapiro, Beth; Rahbek, Carsten; Willerslev, Eske

    2014-01-01

    Despite decades of research, the roles of climate and humans in driving the dramatic extinctions of large-bodied mammals during the Late Quaternary remain contentious. We use ancient DNA, species distribution models and the human fossil record to elucidate how climate and humans shaped the demographic history of woolly rhinoceros, woolly mammoth, wild horse, reindeer, bison and musk ox. We show that climate has been a major driver of population change over the past 50,000 years. However, each species responds differently to the effects of climatic shifts, habitat redistribution and human encroachment. Although climate change alone can explain the extinction of some species, such as Eurasian musk ox and woolly rhinoceros, a combination of climatic and anthropogenic effects appears to be responsible for the extinction of others, including Eurasian steppe bison and wild horse. We find no genetic signature or any distinctive range dynamics distinguishing extinct from surviving species, underscoring the challenges associated with predicting future responses of extant mammals to climate and human-mediated habitat change. PMID:22048313

  19. Invertebrate fossils from cave sediments: a new proxy for pre-Quaternary paleoenvironments

    Science.gov (United States)

    Moldovan, O. T.; Mihevc, A.; Miko, L.; Constantin, S.; Meleg, I. N.; Petculescu, A.; Bosák, P.

    2011-07-01

    Five samples of clastic sediments from interior cave facies taken in three Slovenian relic caves (Trhlovca, Rači\\vska pečina, and a cave in Črnotiče Quarry, Classical Karst, SW Slovenia) provided invertebrate fossil remains. Most of them belong to Oribatida but sparse individuals of Cladocera and insects were also identified. They represent the first pre-Quaternary invertebrate fossils found in sediments of continental temperate climate. The Pliocene/Pleistocene age of the sediments was determined by paleomagnetic dating chronologically calibrated by micromammal biostratigraphy. Invertebrate fossils could be validated as new proxy for the study of cave sediments due to their suitability for ecological and paleogeographic correlations in caves and outside the caves. They also bring additional information about cave formation and karst hydraulic regime in the area. Although the number of remains was very low, it is evidence that climatic conditions in caves allow a better preservation of fossil remains of some groups as compared to most of the surface habitats. This may open a new direction in the study of cave sediments.

  20. Late quaternary history and uranium isotopic compositions of ground water discharge deposits, Crater Flat, Nevada

    International Nuclear Information System (INIS)

    Paces, J.B.; Taylor, E.M.; Bush, C.

    1993-01-01

    Three carbonate-rich spring deposits are present near the southern end of Crater Flat, NV, approximately 18 km southwest of the potential high-level waste repository at Yucca Mountain. We have analyzed five samples of carbonate-rich material from two of the deposits for U and Th isotopic compositions. Resulting U-series disequilibrium ages indicate that springs were active at 18 ± 1, 30 ± 3, 45 ± 4 and >70 ka. These ages are consistent with a crude internal stratigraphy at one site. Identical ages for two samples at two separate sites suggest that springs were contemporaneous, at least in part, and were most likely part of the same hydrodynamic system. In addition, initial U isotopic compositions range from 2.8 to 3.8 and strongly suggest that ground water from the regional Tertiary-volcanic aquifer provided the source for these hydrogenic deposits. This interpretation, along with water level data from near-by wells suggest that the water table rose approximately 80 to 115 m above present levels during the late Quaternary and may have fluctuated repeatedly. Current data are insufficient to allow reconstruction of a detailed depositional history, however geochronological data are in a good agreement with other paleoclimatic proxy records preserved throughout the region. Since these deposits are down gradient from the potential repository site, the possibility of higher ground water levels in the future dramatically shortens both vertical and lateral ground water pathways and reduces travel times of transported radionuclides to potential discharge sites