Formation

Distribution by Scientific Domains
Distribution within Chemistry

Kinds of Formation

  • abscess formation
  • acf formation
  • acid formation
  • acrylamide formation
  • adenoma formation
  • adhesion formation
  • adventitious root formation
  • age formation
  • aggregate formation
  • alliance formation
  • alveolar bone formation
  • amide bond formation
  • amide formation
  • amine formation
  • amyloid fibril formation
  • amyloid formation
  • aneurysm formation
  • antibody formation
  • apoptotic body formation
  • ascites formation
  • atp formation
  • attitude formation
  • autophagosome formation
  • band formation
  • barrier formation
  • base formation
  • basin formation
  • bay formation
  • bile formation
  • biofilm formation
  • biogenic amine formation
  • blastema formation
  • blastocyst formation
  • blister formation
  • blood vessel formation
  • bloom formation
  • body formation
  • bond formation
  • bone formation
  • bridge formation
  • bubble formation
  • by-product formation
  • byproduct formation
  • c bond formation
  • callus formation
  • camp formation
  • canal formation
  • cancer formation
  • capillary formation
  • capillary tube formation
  • capital formation
  • carbon bond formation
  • carbon formation
  • cartilage formation
  • cataract formation
  • cavity formation
  • cell formation
  • cell wall formation
  • cementum formation
  • cgmp formation
  • channel formation
  • char formation
  • circuit formation
  • city formation
  • class formation
  • clot formation
  • cloud formation
  • cluster formation
  • co bond formation
  • coalition formation
  • cocoon formation
  • colony formation
  • commissure formation
  • community formation
  • complex formation
  • compound formation
  • concept formation
  • concomitant formation
  • cone formation
  • consecutive formation
  • contact formation
  • controlled formation
  • cord formation
  • crack formation
  • crater formation
  • crescent formation
  • cross-link formation
  • crust formation
  • crystal formation
  • cultural formation
  • cyclone formation
  • cyst formation
  • de formation
  • de la formation
  • de novo formation
  • decreased bone formation
  • defect formation
  • dendrite formation
  • diastereoselective formation
  • dimer formation
  • direct formation
  • disc formation
  • discursive formation
  • disulfide bond formation
  • disulfide formation
  • dna ladder formation
  • doushantuo formation
  • droplet formation
  • duct formation
  • duplex formation
  • ectomycorrhiza formation
  • ectopic bone formation
  • edema formation
  • efficient formation
  • egg formation
  • embryoid body formation
  • embryonic pattern formation
  • emulsion formation
  • enamel formation
  • endochondral bone formation
  • endoderm formation
  • endosteal bone formation
  • endothelial tube formation
  • enhanced formation
  • enzymatic formation
  • ester formation
  • et la formation
  • ethanol formation
  • ether formation
  • excimer formation
  • exclusive formation
  • expectation formation
  • extracellular matrix formation
  • eye formation
  • family formation
  • fiber formation
  • fibril formation
  • fibrin clot formation
  • fibrin formation
  • filament formation
  • film formation
  • filopodia formation
  • fistula formation
  • flavour formation
  • floc formation
  • foam cell formation
  • focal adhesion formation
  • focus formation
  • follicle formation
  • fragment formation
  • free radical formation
  • galaxy formation
  • gall formation
  • gallstone formation
  • gap formation
  • gel formation
  • gland formation
  • glass formation
  • granulation tissue formation
  • granule formation
  • granuloma formation
  • group formation
  • growth cone formation
  • h-bond formation
  • h2 formation
  • h2o2 formation
  • habit formation
  • hairpin formation
  • hard tissue formation
  • heart formation
  • helix formation
  • hematoma formation
  • heterochromatin formation
  • heterotopic bone formation
  • hippocampal formation
  • histamine formation
  • host-race formation
  • household formation
  • human capital formation
  • hybrid formation
  • hydrate formation
  • hydrogel formation
  • hydrogen bond formation
  • hydrogen-bond formation
  • hyphal formation
  • ice formation
  • identity formation
  • imine formation
  • inclusion body formation
  • inclusion formation
  • incomplete root formation
  • increased bone formation
  • increased formation
  • increment formation
  • inhibitor formation
  • initial formation
  • intermediate formation
  • invadopodia formation
  • involving formation
  • ion formation
  • ion-pair formation
  • iron formation
  • island formation
  • isomer formation
  • junction formation
  • khuff formation
  • la formation
  • lactam formation
  • lactone formation
  • ladder formation
  • lamellipodia formation
  • lateral root formation
  • lattice formation
  • layer formation
  • lesion formation
  • limestone formation
  • local bone formation
  • lufeng formation
  • lumen formation
  • malondialdehyde formation
  • matrix formation
  • membrane formation
  • memory formation
  • mesoderm formation
  • mesophase formation
  • metabolite formation
  • metastasis formation
  • methane formation
  • micelle formation
  • microcolony formation
  • micronucleu formation
  • microstructure formation
  • mineral formation
  • mineralized nodule formation
  • morphology formation
  • myelin formation
  • nanocomposite formation
  • nanoparticle formation
  • nanostructure formation
  • neointima formation
  • neointimal formation
  • network formation
  • neurite formation
  • neurosphere formation
  • new bone formation
  • new formation
  • new vessel formation
  • nft formation
  • nitric oxide formation
  • nitrotyrosine formation
  • niutitang formation
  • no formation
  • nodule formation
  • novel formation
  • novo formation
  • o bond formation
  • oedema formation
  • oligomer formation
  • ongoing star formation
  • opinion formation
  • organ formation
  • osteoblast formation
  • osteoclast formation
  • osteophyte formation
  • oxidative formation
  • oxide formation
  • oxime formation
  • oxygen species formation
  • oxygen vacancy formation
  • pair formation
  • pannu formation
  • papilla formation
  • particle formation
  • pattern formation
  • pedestal formation
  • peptide bond formation
  • peptide formation
  • peroxide formation
  • peroxynitrite formation
  • phase formation
  • pigment formation
  • pit formation
  • planet formation
  • plaque formation
  • plate formation
  • pocket formation
  • podosome formation
  • polar body formation
  • polarity formation
  • polaron formation
  • policy formation
  • polymer formation
  • polymer network formation
  • polyp formation
  • pore formation
  • possible formation
  • potential formation
  • preference formation
  • preferential formation
  • price formation
  • process formation
  • product formation
  • programme de formation
  • pronuclear formation
  • proper formation
  • proplatelet formation
  • protein complex formation
  • pseudocyst formation
  • race formation
  • radical formation
  • rapid formation
  • reactive oxygen species formation
  • recent formation
  • recent star formation
  • recurrent formation
  • regime formation
  • regioselective formation
  • renal stone formation
  • reservoir formation
  • reticular formation
  • reversible formation
  • ring formation
  • ro formation
  • rock formation
  • root formation
  • rosette formation
  • salt formation
  • sandstone formation
  • scale formation
  • scar formation
  • schiff base formation
  • secondary wall formation
  • selective formation
  • septum formation
  • sheet formation
  • shell formation
  • significant bone formation
  • simultaneous formation
  • situ formation
  • skill formation
  • social formation
  • soil formation
  • somite formation
  • species formation
  • sphere formation
  • spheroid formation
  • spindle formation
  • spine formation
  • spontaneous formation
  • spore formation
  • spot formation
  • star formation
  • state formation
  • stereocomplex formation
  • stereoselective formation
  • stoma formation
  • stone formation
  • stress fiber formation
  • stricture formation
  • structural formation
  • structure formation
  • subject formation
  • subsequent formation
  • successful formation
  • sunburn cell formation
  • surface formation
  • symptom formation
  • synapse formation
  • tangle formation
  • teratoma formation
  • ternary complex formation
  • tetramer formation
  • thin film formation
  • thrombin formation
  • thrombus formation
  • tissue formation
  • tooth formation
  • trabecular bone formation
  • tract formation
  • transient formation
  • trimer formation
  • tropical cyclone formation
  • tube formation
  • tubule formation
  • tumor formation
  • tumour formation
  • ulcer formation
  • unexpected formation
  • union formation
  • vacancy formation
  • vacuole formation
  • valve formation
  • vascular formation
  • vein formation
  • vesicle formation
  • vessel formation
  • vitro formation
  • vivo bone formation
  • vivo formation
  • void formation
  • wage formation
  • wall formation
  • wood formation
  • wrinkle formation
  • xylem formation
  • zone formation

  • Terms modified by Formation

  • formation ability
  • formation activity
  • formation age
  • formation behavior
  • formation capacity
  • formation clearance
  • formation condition
  • formation constant
  • formation efficiency
  • formation energy
  • formation enthalpy
  • formation history
  • formation kinetics
  • formation lead
  • formation marker
  • formation mechanism
  • formation model
  • formation models
  • formation only
  • formation pathway
  • formation pattern
  • formation pressure
  • formation process
  • formation property
  • formation rate
  • formation reaction
  • formation scenario
  • formation source rock
  • formation stage
  • formation step
  • formation time
  • formation time-scale
  • formation water

  • Selected Abstracts


    MORAL FORMATION, CULTURAL ATTACHMENT OR SOCIAL CONTROL: WHAT'S THE POINT OF VALUES EDUCATION?

    EDUCATIONAL THEORY, Issue 1 2000
    David Carr
    First page of article [source]


    DYNAMICS OF POLYPLOID FORMATION IN TRAGOPOGON (ASTERACEAE): RECURRENT FORMATION, GENE FLOW, AND POPULATION STRUCTURE

    EVOLUTION, Issue 7 2010
    V. Vaughan Symonds
    Polyploidy is a major feature of angiosperm evolution and diversification. Most polyploid species have formed multiple times, yet we know little about the genetic consequences of recurrent formations. Among the clearest examples of recurrent polyploidy are Tragopogon mirus and T. miscellus (Asteraceae), each of which has formed repeatedly in the last ,80 years from known diploid progenitors in western North America. Here, we apply progenitor-specific microsatellite markers to examine the genetic contributions to each tetraploid species and to assess gene flow among populations of independent formation. These data provide fine-scale resolution of independent origins for both polyploid species. Importantly, multiple origins have resulted in considerable genetic variation within both polyploid species; however, the patterns of variation detected in the polyploids contrast with those observed in extant populations of the diploid progenitors. The genotypes detected in the two polyploid species appear to represent a snapshot of historical population structure in the diploid progenitors, rather than modern diploid genotypes. Our data also indicate a lack of gene flow among polyploid plants of independent origin, even when they co-occur, suggesting potential reproductive barriers among separate lineages in both polyploid species. [source]


    ORGANIZATIONAL CHANGE, SKILL FORMATION, HUMAN CAPITAL MEASUREMENT: EVIDENCE FROM ITALIAN MANUFACTURING FIRMS

    JOURNAL OF ECONOMIC SURVEYS, Issue 2 2010
    Gilberto Antonelli
    Abstract This paper emphasizes the role of labour demand as a determinant of human capital formation. After a section in which the alternative conceptions on the functioning of labour markets are presented and different ways of measuring human capital are compared, an applied analysis is carried out in which we provide a labour-demand-oriented measure of human capital, as defined by the amount of specific skills firms generate through work-based training (WBT) activities. By merging three rich firm-level datasets, we estimate the impact of a set of variables supposed to affect both the propensity to invest in WBT and the intensity of training within the Italian manufacturing industry over the period 2001,2005. Special attention is devoted to the variables characterizing within-firm organization of knowledge, organizational change and the formation of competence pipelines: among them, innovation, internationalization commitment, out-sourcing and new hirings. The estimates show that the effect of innovation on WBT is higher when the introduction of new technologies is supported by organizational innovations. When looking at the nature of WBT, we investigate the different determinants of the firms' propensity to provide both in-house and outside training. We measure training intensity in terms, respectively, of the number of provided training activities, private and total training costs and share of trainees. [source]


    EFFECT OF STORAGE TEMPERATURE ON HISTAMINE FORMATION IN SARDINA PILCHARDUS AND ENGRAULIS ENCRASICOLUS AFTER CATCH

    JOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2007
    PIERINA VISCIANO
    ABSTRACT Histamine formation in Sardina pilchardus and Engraulis encrasicolus as a function of storage temperature was studied. Fish were caught off the Adriatic Coast and were carried immediately to the laboratory. A portion of dorsal muscle from each fish was soon analyzed, while two other portions were examined after storage at two different temperatures (25 and 4C) for 24 and 72 h, respectively. The analyses were carried out by high-performance liquid chromatography (HPLC)-UV and confirmed by HPLC-diode array detector. Histamine concentrations were always higher than the European Community admissible levels in samples stored at 25C. In fish stored at 4C, histamine was detected only in E. encrasicolus. PRACTICAL APPLICATIONS Time experiments were conducted to quantify the histamine formation in scombroid species at two different temperatures. The first assay (24 h, 25C) could reproduce the modality of sale adopted by fishermen or retailers in summer on the one hand, and the maintenance at ambient temperature of semipreserved sardines or anchovies during salting and ripening on the other hand. The second experiment (72 h, 4C) was based on the domestic cold preservation of fish before the consumption, which sometimes occurs some days after purchasing. Even if ice storage is recommended, time/temperature abuse conditions often occur in the fish merchandising chain. The results of this research showed that high histamine concentrations could be found in the analyzed species not only at an abused temperature, but also at a common storage temperature of fish at home. [source]


    ANALYSIS AND FORMATION OF ACRYLAMIDE IN FRENCH FRIES AND CHICKEN LEGS DURING FRYING

    JOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2006
    W.H. CHUANG
    ABSTRACT The analysis and formation of acrylamide in French fries and chicken legs during frying were studied. Results showed that the most appropriate extraction solvent was ethyl acetate, with C-18 cartridge for purification and 5-mL deionized water as elution solvent. Dibromination of acrylamide followed by dehydrobromination to 2-bromopropionamide in the presence of triethylamine was necessary for subsequent analysis by gas chromatography,mass spectrometry. The most appropriate temperature programming condition was as follows: 70C in the beginning, raised to 150C at a rate of 10C/min, maintained for 1 min and to 240C at a rate of 30C/min, maintained for 5 min. Detection was carried out using selected-ion monitoring mode, and N,N -dimethylacrylamide was used as internal standard for quantification. French fries and the outer flour portion of chicken legs fried at 180C generated a higher level of acrylamide than at 160C. Compared to soybean oil and palm oil, a lower amount of acrylamide was produced in French fries and the outer flour portion of chicken legs fried in lard. However, no acrylamide was detected in the inner meat portion of fried chicken legs. [source]


    KINETICS OF ACRYLAMIDE FORMATION DURING TRADITIONAL AND VACUUM FRYING OF POTATO CHIPS

    JOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2005
    CLAUDIA GRANDA
    ABSTRACT Acrylamide is considered a carcinogen in animals and a possible carcinogen in humans. It has been found in starch-rich foods cooked at high temperatures. Vacuum frying (10 Torr) was investigated as a possible alternative to reduce acrylamide formation in potato chips. The cultivar Atlantic was used to determine the kinetics of acrylamide formation during traditional and vacuum frying at different temperatures. There was a 94% decrease in acrylamide content when potatoes were fried to the same final moisture content (1.5% ± 0.3% w.b.) under vacuum compared to those fried under atmospheric conditions. Acrylamide accumulation under vacuum frying was modeled using first-order kinetics (during traditional frying, the logistic kinetic model was used). The behavior of the kinetics of acrylamide content in potato chips fried under the two processes was different mainly because of the different temperatures used. During traditional frying, higher temperatures are used (150 to 180C) and acrylamide after some time is produced but starts degrading, producing a constant level of acrylamide content at longer times. During vacuum frying (10 Torr), acrylamide increased exponentially (but at lower levels) for all frying times. [source]


    EFFECTS OF COOKED TEMPERATURES AND ADDITION OF ANTIOXIDANTS ON FORMATION OF HETEROCYCLIC AROMATIC AMINES IN PORK FLOSS

    JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2009
    GUOZHOU LIAO
    ABSTRACT Heterocyclic aromatic amines (HAAs) are an important class of food mutagens and carcinogens produced in meats cooked at high temperature. The formation of HAAs in pork floss during processing and the effect of vitamin C and vitamin E on HAAs formation in pork floss were studied. Pork floss was prepared by steaming of raw pork, followed by pressing, tearing, adding various additives, and then the cooked pork was subjected to stir frying. The various HAAs in pork floss were isolated by solid phase extraction and analyzed by high-performance liquid chromatography (HPLC). Results showed that the type and level of HAAs increased with increasing processing temperature. Up to seven HAAs, 9H-pyrido[4,3-b]indole (Norharman), 1-methyl-9H-pyrido[4,3-b]indole (Harman), 2-amino-1- methyl-6-phenylimidazo[4,5-f]pyridine (PhIP), 2-amino-dipyrido[1,2-a: 3,,2,-d]imidazole (Glu-P-2), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-9H-pyrido[2,3-b]indole (AaC) and 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAaC) were detected in pork floss when stir fried at 150C. Color development increased with cooking temperatures, and was correlated with HAAs formation. The addition of vitamin C at various levels was not effective toward HAAs inhibition. However, the incorporation of 0.1% vitamin E reduced Norharman, PhIP, AaC and MeAaC concentrations in the pork floss. PRACTICAL APPLICATION The formation of heterocyclic aromatic amines (HAAs) is one of the most unfavorable changes during the cooking of food. Since the connection between the consumption of dietary carcinogens and cancer risks in human has been established, interest in this matter has been growing. However, the processing methods and conditions of Chinese traditional food are different from Western, and to date, little is known about HAAs content in the traditional meat products of China. The information derived from this study serves as an essential base of knowledge from a public health standpoint, and contributes to a repository of HAAs information relevant to Chinese cooking; it also can provide clues to understanding the factors that affect HAAs formation and can indicate means of reducing or eliminating these compounds. [source]


    BACTERIAL FORMATION OF HISTAMINE IN JACK MACKEREL (TRACHURUS SYMMETRICUS)

    JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3 2004
    A. BERMEJO
    ABSTRACT Peak histamine concentrations of 0.023, 0.031 and 0.027 g histamine/100 g muscle and maximal bacteria concentrations of 1.75, 1.59 and 0.423 g dry cells/100 g muscle were observed in muscles of jack mackerel stored at 25, 15 and 5C, respectively. Incubated fish homogenates suggest rate and transport limitations in histamine formation in muscle. The Mulchandani model predicted bacterial growth in muscle. The Luedeking and Piret expression fitted histamine formation in muscle; , values were 3.0 × 10,3, 1.23 × 10,2 and 4.17 × 10,2 g histamine/g dry cells, while ,-values were 4.5 × 104, 8.0 × 10,5 and 0 g histamine/g dry cells × h at 25, 15, and 5C, respectively. The model predicts that jack mackerel could be stored from 4.5 to 5.5 days in ice, from 1 to 2 days at 15C and from 17 h to 2 days at 25C before fishmeal quality might be affected. [source]


    RELATIONSHIP BETWEEN ORGANIC MATTER, SULPHUR AND PHOSPHATE CONTENTS IN UPPER CRETACEOUS MARINE CARBONATES (KARABOGAZ FORMATION, SE TURKEY): IMPLICATIONS FOR EARLY OIL GENERATION

    JOURNAL OF PETROLEUM GEOLOGY, Issue 4 2010
    S. Inan
    In this paper, we discuss the relationship between the organic matter, sulphur and phosphate contents of Upper Cretaceous marine carbonates (Karabogaz Formation) in the Adiyaman Petroleum Province of SE Turkey. The results of organic geochemical analyses of core samples obtained from the Karabogaz Formation suggest that phosphate deposition occurred in settings where the water column was oxic to sub-oxic. However, the preservation of organic matter was favoured in anoxic environments. Moreover, the presence of sulphur (especially sulphur incorporated into kerogen) in organic matter-rich layers led to early oil generation. The results of stepwise py-gc analyses are consistent with a model in which, with increasing maturity, S-S and C-S bonds are the first to be eliminated from the macromolecular kerogen structure. Study of the maturity evolution of S-rich kerogen by laboratory pyrolysis implies that marginally mature and/or mature kerogen in the Karabogaz Formation, which may be classified as classic "Type II" kerogen, was most probably Type II/S at lower maturity stages. This enabled oil generation to occur at relatively shallow burial depths and relatively early stages of maturation. It is reasonable to conclude that Type II/S kerogen, overlooked in previous studies, was abundant in TOC-rich intervals in the Karabogaz Formation. Early generation (and expulsion) from Type II/S kerogen may have sourced the sulphur-rich oils in the Adiyaman area oilfields. [source]


    AN AEOLIANITE IN THE UPPER DALAN MEMBER (KHUFF FORMATION), SOUTH PARS FIELD, IRAN

    JOURNAL OF PETROLEUM GEOLOGY, Issue 2 2010
    G. Frébourg
    A laterally continuous, 3m thick oolitic grainstone has been studied in cores from two wells from the South Pars field (offshore Iran). This high porosity but low permeability interval occurs at the top of the gas-bearing succession in the Permian Upper Dalan Member, and is equivalent to the informally-defined K4 unit of the Khuff Formation. This interval can easily be traced between the wells and overlies high-energy marine deposits. It is composed of oomouldic, fine-grained azooic grainstones with cm-thick coarser-grained layers. Horizontal to oblique lamination or steep foresets were observed together with pinstripe lamination. Petrographic observations indicate a clean oomouldic grainstone with very thin chitonic rims associated with pedogenetic imprints as first-generation cements. Later cements include early vadose meniscus and pendant cements in coarser-grained layers and pseudophreatic cements in the finer-grained material with a tighter pore network, prior to ooid dissolution. Rhizoliths were observed in cores and thin-sections. The pedogenic imprints and the early vadose cementation, both related to emergence, as well as the presence of pinstripe lamination, suggest an aeolian depositional setting. This interval is the first aeolianite recorded within the Khuff Formation or equivalent units, and the first hydrocarbon-bearing carbonate aeolianite described in a hydrocarbon-producing unit. The discovery of aeolianites has important implications for regional sequence-stratigraphic interpretations and reservoir volume calculations. These deposits do not conform to classic subaqueous sequence stratigraphy and do not record eustatic variations in the associated marine basin. Their recognition is crucial for well-to-well correlations. [source]


    BURIAL HISTORY RECONSTRUCTION USING LATE DIAGENETIC PRODUCTS IN THE EARLY PERMIAN SILICICLASTICS OF THE FARAGHAN FORMATION, SOUTHERN ZAGROS, IRAN

    JOURNAL OF PETROLEUM GEOLOGY, Issue 2 2009
    S. M. Zamanzadeh
    In spite of the increasing importance to hydrocarbon exploration and production of the Palaeozoic succession in the Zagros area of SW Iran, few burial history and palaeothermal modelling studies of the interval have been carried out. This paper attempts to assess the burial and palaeotemperature history of the Lower Permian Faraghan Formation which is composed of stromatolitic dolomites overlain by mainly cross-bedded sandstones. The formation grades up into the thick bedded carbonates of the Upper Permian Dalan Formation. The Faraghan and Dalan Formations are major hydrocarbon reservoir units in SW Iran and are time-equivalents of the Unayzah and Khuff Formations in Saudi Arabia, respectively. The Faraghan Formation consists of shallow-marine siliciclastics and foreshore deposits, including tidal-flat and tidal-channel, estuarine, sabkha, shoreface and offshore facies. In this study, diagenetic constituents are used to evaluate the formation's burial history in the Southern Zagros, an area for which only limited subsurface data is available. A burial history diagram for the formation was constructed for well Finu # 1 using WinBuryTM software. The diagram shows that the formation underwent progressive burial at variable rates between its deposition and the mid-Tertiary, since when it has undergone rapid uplift. Burial diagenetic products in the Faraghan Formation comprise saddle, ferroan and zoned dolomites, together with dickite, illite/sericite and chlorite minerals. Additional burial-related features include stylolites and dissolution seams. Isotopic signatures (,18O versus ,13C) of the ferroan dolomites suggest a burial trend for the formation. Reconstruction of the paragenetic sequence together with the burial history diagram suggests a maximum burial depth of about 5000 m and a wide palaeotemperature range of 80-160°C. However considering the saddle dolomites as a palaeothermometer, the temperature range narrows to 78 to 138 °C. The burial depth and temperature ranges closely correlate with the main stage of oil generation to the dry gas zone. [source]


    AN INTEGRATED STUDY OF DIAGENESIS AND DEPOSITIONAL FACIES IN TIDAL SANDSTONES: HAWAZ FORMATION (MIDDLE ORDOVICIAN), MURZUQ BASIN, LIBYA

    JOURNAL OF PETROLEUM GEOLOGY, Issue 1 2009
    A. Abouessa
    Studies of the impact of diagenesis on reservoir quality in tidal sandstones can be of great importance in successful hydrocarbon exploration. The study reported here shows that diagenetic alterations and bioturbation have induced considerable deterioration and heterogeneity in the reservoir quality of the sand-dominated tidal deposits of the Middle Ordovician Hawaz Formation in the Muruq Basin, Libya. Comparison is made between the diagenetic evolution of samples from the subsurface (present-day depth 1500 m) and from surface outcrops in order to study the impact of burial and uplift on the spatial and temporal distribution of reservoir quality in the Hawaz Formation sandstones. Eogenetic alterations, which were mediated by meteoric water circulation, included kaolinitization and dissolution of framework silicates and mechanical compaction. Mesogenetic alterations (T > 70°C; depth > 2 km) included pressure dissolution of quartz grains and concomitant quartz cementation, conversion of kaolinite into dickite, illitization of kaolinite and of grain-coating clays, and the precipitation of Mg-rich siderite cement. Reduction of intergranular porosity was due more to compaction than to cementation, yet quartz overgrowths are up to 16% in some of the sandstones. Bioturbation has resulted in a greater reduction in sandstone permeability in the lower part of the formation than the upper part. A higher ratio of dickite to kaolinite in subsurface samples than in outcrop samples is attributed to the longer residence time of the former sandstones under mesogenetic conditions. Telodiagenesis has not resulted in enhancement of reservoir quality of the Hawaz Formation Sandstones but in pseudomorphic calcitization of siderite and oxidation of pyrite to goethite. This study shows that the reservoir-quality evolution of tidal sandstones can best be elucidated when linked to depositional facies and distribution of diagenetic alterations. [source]


    MAPPING AND CLASSIFYING FLOW UNITS IN THE UPPER PART OF THE MID-CRETACEOUS SARVAK FORMATION (WESTERN DEZFUL EMBAYMENT, SW IRAN) BASED ON A DETEMINATION OF RESERVOIR ROCK TYPES

    JOURNAL OF PETROLEUM GEOLOGY, Issue 4 2007
    B. Beiranvand
    The mid-Cretaceous Sarvak Formation, the second-most important reservoir unit in Iran, is composed mainly of grain-supported carbonates. For the purposes of this study, flow units in the upper part of the formation were identified, mapped and classified as part of an integrated reservoir characterization study at a giant oilfield in SW Iran. Pore types and geometries, pore-scale diagenetic history and core-scale depositional attributes were logged using conventional petrographic and lithological methods. The resulting data were combined with core descriptions, mercury-injection capillary pressure data, and wireline log and geophysical data to identify five reservoir rock types: (i) highly oil-stained, grain-supported carbonates, including patch reef and barrier complex deposits with high porosities and permeabilities; (ii) leeward and seaward shoal deposits including grain-supported packstones and skeletal wackestones with high porosities and permeabilities; (iii) dominantly mud-supported lagoonal and open-marine facies with fair porosity and permeability; (iv) grain-supported but highly cemented facies which had poor reservoir characteristics; and (v) calcareous shales and shaly limestones with no reservoir quality. Based on the reservoir rock types, eight flow units were recognised. Subsequently, four reservoir zones were defined based on these flow units at a field scale. This study has contributed to our understanding of flow units in this complex carbonate reservoir, and has improved our ability to characterize and model the architecture of the reservoir from pore to core to field scale. [source]


    SEISMIC FACIES ANALYSIS BASED ON 3D MULTI-ATTRIBUTE VOLUME CLASSIFICATION, DARIYAN FORMATION, SE PERSIAN GULF

    JOURNAL OF PETROLEUM GEOLOGY, Issue 2 2006
    P. Farzadi
    Interpretation of recently acquired 3D seismic data from the adjacent Sirri C and D oilfields in the SE Persian Gulf indicates that a 3D interpretation of seismic facies is crucial to resolve the internal stratal geometries of the Aptian Dariyan Formation. This carbonate formation passes southward into the Shu'aiba Formation, a prolific reservoir rock of similar facies in the UAE. Lack of exposures and limited cored intervals have forced reliance on the seismic data for evidence of the depositional environment and the internal architecture of potential reservoir rocks. The progradational nature of the Dariyan Formation and the occurrence of carbonate build-ups within it make this stratal geometry complex. The complex internal heterogeneity of the build-ups and presence of seismic noise make mapping of the build-ups in 3D space using conventional seismic interpretation tools difficult, despite the availability of high-quality 3D seismic data covering the area. The high quality seismic and limited well data from this field is one of the few datasets of this kind presented in the literature. A procedure for the hierarchical multi-attribute analysis of seismic facies using Paradigm's Seis Facies software is used in this study to provide a 3D interpretation of the stratal patterns. Principal component analysis reduces the noise and redundant data by representing the main data variances as a few vector components in a transformed coordinate system. Cluster analysis is performed using those components which have the greatest contribution to the maximum spread of the data variability. Six seismic attribute volumes are used in this study and the result is a single 3D classified volume. Important new information obtained from within the Dariyan Formation gives new insights into its stratigraphic distribution and internal variability. This method of processing seismic data is a step towards exploring for subtle stratigraphic traps in the study area, and may help to identify exploration targets. [source]


    HYDROCARBON SEEPAGE AND CARBONATE MOUND FORMATION: A BASIN MODELLING STUDY FROM THE PORCUPINE BASIN (OFFSHORE IRELAND)

    JOURNAL OF PETROLEUM GEOLOGY, Issue 2 2005
    J. Naeth
    This study assesses whether the growth of deep water carbonate mounds on the continental slope of the north Atlantic may be associated with active hydrocarbon leakage. The carbonate mounds studied occur in two distinct areas of the Porcupine Basin, 200 km offshore Ireland, known as the Hovland-Magellan and the Belgica areas. To evaluate the possible link between hydrocarbon leakage and mound growth, we used two dimensional cross-section and map-based basin modelling. Geological information was derived from interpretation of five seismic lines across the province as well as the Connemara oilfield. Calibration data was available from the northern part of the study area and included vitrinite reflectance, temperature and apatite fission track data. Modelling results indicate that the main Jurassic source rocks are mature to overmature for hydrocarbon generation throughout the basin. Hydrocarbon generation and migration started in the Late Cretaceous. Based on our stratigraphic and lithologic model definitions, hydrocarbon migration is modelled to be mainly vertical, with only Aptian and Tertiary deltaic strata directing hydrocarbon flow laterally out of the basin. Gas chimneys observed in the Connemara field were reproduced using flow modelling and are related to leakage at the apices of rotated Jurassic fault blocks. The model predicts significant focussing of gas migration towards the Belgica mounds, where Cretaceous and Tertiary carrier layers pinch out. In the Hovland-Magellan area, no obvious focus of hydrocarbon flow was modelled from the 2D section, but drainage area analysis of Tertiary maps indicates a link between mound position and shallow Tertiary closures which may focus hydrocarbon flow towards the mounds. [source]


    SOURCE ROCK PROPERTIES OF LACUSTRINE MUDSTONES AND COALS (OLIGOCENE DONG HO FORMATION), ONSHORE SONG HONG BASIN, NORTHERN VIETNAM

    JOURNAL OF PETROLEUM GEOLOGY, Issue 1 2005
    H. I. Petersen
    Oligocene lacustrine mudstones and coals of the Dong Ho Formation outcropping around Dong Ho, at the northern margin of the mainly offshore Cenozoic Song Hong Basin (northern Vietnam), include highly oil-prone potential source rocks. Mudstone and coal samples were collected and analysed for their content of total organic carbon and total sulphur, and source rock screening data were obtained by Rock-Eval pyrolysis. The organic matter composition in a number of samples was analysed by reflected light microscopy. In addition, two coal samples were subjected to progressive hydrous pyrolysis in order to study their oil generation characteristics, including the compositional evolution in the extracts from the pyrolysed samples. The organic material in the mudstones is mainly composed of fluorescing amorphous organic matter, liptodetrinite and alginite with Botryococcus-morphology (corresponding to Type I kerogen). The mudstones contain up to 19.6 wt.% TOC and Hydrogen Index values range from 436,572 mg HC/g TOC. From a pyrolysis S2 versus TOC plot it is estimated that about 55% of the mudstones'TOC can be pyrolised into hydrocarbons; the plot also suggests that a minimum content of only 0.5 wt.% TOC is required to saturate the source rock to the expulsion threshold. Humic coals and coaly mudstones have Hydrogen Index values of 318,409 mg HC/g TOC. They are dominated by huminite (Type III kerogen) and generally contain a significant proportion of terrestrial-derived liptodetrinite. Upon artificial maturation by hydrous pyrolysis, the coals generate significant quantities of saturated hydrocarbons, which are probably expelled at or before a maturity corresponding to a vitrinite reflectance of 0.97%R0. This is earlier than previously indicated from Dong Ho Formation coals with a lower source potential. The composition of a newly discovered oil (well B10-STB-1x) at the NE margin of the Song Hong Basin is consistent with contributions from both source rocks, and is encouraging for the prospectivity of offshore half-grabens in the Song Hong Basin. [source]


    TEMPESTITE DEPOSITS ON A STORM-INFLUENCED CARBONATE RAMP: AN EXAMPLE FROM THE PABDEH FORMATION (PALEOGENE), ZAGROS BASIN, SW IRAN

    JOURNAL OF PETROLEUM GEOLOGY, Issue 2 2004
    H. Mohseni
    The Pabdeh Formation is part of a thick carbonate-siliciclastic succession in the Zagros Basin of SW Iran which includes carbonate reservoirs of Cretaceous and Cenozoic ages. From field observations and petrographic and facies analysis of exposures in the type section of the Pabdeh Formation, four lithofacies were recognized. These are from oldest to youngest: (i) a mottled, bioturbated bioclastic wackestone/mudstone facies; (ii) a wackestone/packstone facies with horizontal burrows on bedding planes; (iii) a thin-bedded bioclastic wackestone/mudstone facies alternating with thin bioclastic-oolitic-intraclastic intervals; and (iv) a bioclastic foraminiferal / algal / peloidal packstone facies. These observations indicate that facies evolved upwards from deep outer-ramp deposits to inner-ramp deposits within a shoal complex, suggesting progradation of the ramp depositional system. Storm events significantly influenced the ramp system. Storm-generated surges transported sediments from nearshore to the deeper outer-ramp environment where they were deposited as shell-lags, composed mostly of bioclastic packstones, rich in pelagic microfauna with sharp, undulatory erosional basal contacts. The packstones rest on outer ramp mudstones deposited below storm base level. Sedimentary structures in the Pabdeh Formation are those typical of storm deposits, such as hummocky cross-stratification, ripple cross-lamination, ripple marks, escape burrows on the tops of the beds, couplets of fine- and coarse-grained laminae and mixed fauna, as well as intraclasts derived from underlying facies. These distinctive sequences are interpreted to have been generated by waning storm-generated currents. The dominance of fine-grained sediments (medium to fine sand); the lack of large- scale hummocky cross-stratification; the minor amounts of intraclasts derived from underlying facies; the paucity of amalgamated tempestite beds; and the finely-laminated (mm to cm scale) couplets of coarse and fine lamina all suggest a distal tempestite facies. Palaeogeographic reconstruction of the Zagros Basin during the Eocene indicates that the study area was situated in tropical, storm-dominated palaeolatitudes. [source]


    NEURAL NETWORK PREDICTION OF PERMEABILITY IN THE EL GARIA FORMATION, ASHTART OILFIELD, OFFSHORE TUNISIA

    JOURNAL OF PETROLEUM GEOLOGY, Issue 4 2001
    J.H. Ligtenberg
    The Lower Eocene El Garia Formation forms the reservoir rock at the Ashtart oilfield, offshore Tunisia. It comprises a thick package of mainly nummulitic packstones and grainstones with variable reservoir quality. Although porosity is moderate to high, permeability is often poor to fair with some high permeability streaks. The aim of this study was to establish relationships between log-derived data and core data, and to apply these relationships in a predictive sense to uncored intervals. An initial objective was to predict from measured logs and core data the limestone depositional texture (as indicated by the Dunham classification), as well as porosity and permeability. A total of nine wells with complete logging suites, multiple cored intervals with core plug measurements together with detailed core interpretations were available. We used a fully-connected Multi-Layer-Perceptron network (a type of neural network) to establish possible non-linear relationships. Detailed analyses revealed that no relationship exists between log response and limestone texture (Dunham class). The initial idea to predict Dunham class, and subsequently to use the classification results to predict permeability, could not therefore be pursued. However, further analyses revealed that it was feasible to predict permeability without using the depositional fabric, but using a combination of wireline logs and measured core porosity. Careful preparation of the training set for the neural network proved to be very important. Early experiments showed that low to fair permeability (1,35 mD) could be predicted with confidence, but that the network failed to predict the high permeability streaks. "Balancing " the data set solved this problem. Balancing is a technique in which the training set is increased by adding more examples to the under-sampled part of the data space. Examples are created by random selection from the training set and white noise is added. After balancing, the neural network's performance improved significantly. Testing the neural network on two wells indicated that this method is capable of predicting the entire range of permeability with confidence. [source]


    A REVIEW OF EOCENE NUMMULITE ACCUMULATIONS: STRUCTURE, FORMATION AND RESERVOIR POTENTIAL

    JOURNAL OF PETROLEUM GEOLOGY, Issue 1 2001
    A. Racey
    Eocene nummulite accumulations, also referred to as nummullte "banks", form Important hydrocarbon reservoirs in Tunisia and Libya and may constitute exploration targets in other parts of North Africa, the Mediterranean and the Middle East. Porosities commonly average 10,20% and permeabilities 10,50md. Foraminifera of the genus Nummulites may comprise up to 98% of the bioclasts in these carbonate reservoirs, although only one or two species may be present. The absence of associated fauna is generally taken to indicate an oligotrophic depositional environment. In this paper, the palaeoecology of the genus Nummulites is discussed together with depositional models for two nummulitic carbonate reservoirs , the Middle Eocene Seeb Limestone of Oman and the Early Eocene El Garia/Jdeir Formation of Tunisia and Libya. The El Garia and Seeb Limestone Formations were deposited in ramp settings, and comprise a series of amalgamated sheets or low-relief banks. In the Hasdrubal field offshore Tunisia, where the El Garia Formation constitutes the reservoir rock, most of the nummulites have been redeposited from shallow into deeper waters whilst in the Bourri field (offshore Libya) they occur as an in situ "bank". Nummulite accumulations often show evidence that both physical reworking (scouring, winnowing and imbrication) and biological processes (reproduction strategies and bioturbation) have influenced their formation. A general model is outlined for discriminating between physically and ecologically produced biofabrics, and the implications for reservoir quality are discussed. [source]


    DEPOSITIONAL ENVIRONMENT AND DIAGENESIS OF THE EOCENE JDEIR FORMATION, GABES-TRIPOLI BASIN, WESTERN OFFSHORE, LIBYA

    JOURNAL OF PETROLEUM GEOLOGY, Issue 4 2000
    J. M. Anketell
    The late Ypresian (early Eocene) Jdeir Formation was deposited in the Mesozoic-Cenozoic Gabes-Tripoli Basin, offshore Libya. The basin developed on the northern passive margin of the African Plate and was relatively unstable being affected by syn-sedimentary tectonic movements. Deposition was coeval with a relative rise of sea-level and the subsequent highstand. A lower, thinly-developed nummulitic bank facies with restricted distribution records the transgressive event and is succeeded by more micritic sediments that record the time of maximum flooding. The succeeding sea-level highstand is represented by a thick, and widely developed, progradational-aggradational nummulitic sequence that displays lateral changes across WE-ESE trending facies belts. Three major lithofacies are recognized in the Jdeir Formation: Nummulites packstone-grainstone, Alveolina-Orbitoliteswackestone-packtone, andFragmental-Discocyclina-Assilina wackestone-packstone, depositedin bank, back-bank, and fore-bank environments, respectively. The formation passes to the NNE into the pelagic lithofacies of the Hallab Formation; landward, to the south, it passes into shoreline evaporitic facies of the Taljah Formation. The lithofacies were structurally controlled by contemporaneous and/or syndepositional tectonic movements, with nummulitic facies tending to develop on uplifted areas. Petrographic and petrophysical studies indicate that porosity in the Jdeir Formation is controlled by depositional environment, tectonic setting and diagenesis. The combined effects of salt tectonics, a major unconformity at the top of the formation and meteoric diagenesis have produced excellent-quality reservoir facies at the Bouri oilfield and in other areas. Porosity is highest in the nummulitic bank facies and lowest in the Alveolina-Orbitolites micrite facies. Good to excellent reservoir quality occurs in the upper part of the nummulitic packstone-grainstone facies, especially where these sediments overlie structurally high areas. High rates of dissolution found at the crests of domes and anticlines suggest that early diagenetic processes and features are, in part, structurally controlled. Future exploration success will depend on investigation of similar structures within the Gabes-Tripoli Basin. Both porosity initiation and preservation are related to early depositional and diagenetic processes. The wide time-gap between hydrocarbon generation and reservoir formation points to the role of the seal in porosity preservation and rules out the assumption that early emplacement of oil had preserved the porosity. [source]


    DOLOMITIZATION OF THE EARLY EOCENE JIRANI DOLOMITE FORMATION, GABES-TRIPOLI BASIN, WESTERN OFFSHORE, LIBYA

    JOURNAL OF PETROLEUM GEOLOGY, Issue 4 2000
    I. Y. Mriheel
    Dolomitization in the early Eocene Jirani Formation in the Gabes-Tripoli Basin (offshore western Libya) occurred in two stages. Stage I dolomites are composed of two types, one associated with anhydrite (Type I) the other anhydrite free (Type II,). The stratigraphic and sedimentological settings together with petrographic and geochemical criteria suggest that dolomitization was effected by refluxed evaporative seawater. Stable isotope and trace element analyses suggest dolomitization of both Types from a fluid of near-surface seawater composition under oxidising conditions modified by evaporation. Non-luminescence and lack ofzonation of all the dolomite indicate that the dolomitizing fluids maintained a relatively constant composition. The geologic setting during the early Eocene, interpreted as hypersaline lagoon, supports an evaporative reflux origin for the anhydritic dolomite Type I. Type II developed under less saline conditions in the transition zone between lagoon and open marine shelf. Stage II dolomitization is recorded by negative isotope values in both Types I and II indicating their dissolution and recrystallization (neomorphism) by dilute solutions. A period of exposure of the overlying Jdeir Formation following a relative sea-level fall allowed ingress of meteoric waters into both the Jdeir and the underlying Jirani Formations. Flushing by meteoric waters also resulted in development of excellent secondaly porosity and caused major dissolution of anhydrite to form the anhydritic-free dolomite facies typical of Type II. Following, and possibly during, both Stages I and II, low temperature dolomites (Type IIIa) precipitated in pore spaces from residual jluids at shallow burial depths, partially occluding porosity. In the late stage of basin evolution, medium clystalline, pore-filling saddle dolomite precipitated, causing some filling of mouldic and vuggy porosity (Type IIIb). Very light oxygen isotopic signatures confirm that it developed from high temperature fluids during deep burial diagenesis. Calculation of temperatures and timings of the dolomitization and cement phases show that the main dolomitization phases and Type IIIa cements occurred in the early Eocene, and that the saddle dolomite precipitated in the Miocene; these results are consistent with age relationships established from stratigraphic, petrographic and geochemical signatures. The most common porosity includes intercrystal, vuggy and mouldic types. Porosity is both pre-dolomitization and syn-dolomitization in origin, but the latter is the most dominant. Hence, reservoir quality is largely controlled by fluid dynamics. [source]


    A VANADIUM BROMOPEROXIDASE CATALYZES THE FORMATION OF HIGH-MOLECULAR-WEIGHT COMPLEXES BETWEEN BROWN ALGAL PHENOLIC SUBSTANCES AND ALGINATES,

    JOURNAL OF PHYCOLOGY, Issue 1 2009
    Leonardo Tavares Salgado
    The interaction between phenolic substances (PS) and alginates (ALG) has been suggested to play a role in the structure of the cell walls of brown seaweeds. However, no clear evidence for this interaction was reported. Vanadium bromoperoxidase (VBPO) has been proposed as a possible catalyst for the binding of PS to ALG. In this work, we studied the interaction between PS and ALG from brown algae using size exclusion chromatography (SEC) and optical tweezers microscopy. The analysis by SEC revealed that ALG forms a high-molecular-weight complex with PS. To study the formation of this molecular complex, we investigated the in vitro interaction of purified ALG from Fucus vesiculosus L. with purified PS from Padina gymnospora (Kütz.) Sond., in the presence or absence of VBPO. The interaction between PS and ALG only occurred when VBPO was added, indicating that the enzyme is essential for the binding process. The interaction of these molecules led to a reduction in ALG viscosity. We propose that VBPO promotes the binding of PS molecules to the ALG uronic acids residues, and we also suggest that PS are components of the brown algal cell walls. [source]


    PURIFICATION AND CHARACTERIZATION OF A LECTIN, BRYOHEALIN, INVOLVED IN THE PROTOPLAST FORMATION OF A MARINE GREEN ALGA BRYOPSIS PLUMOSA (CHLOROPHYTA) ,

    JOURNAL OF PHYCOLOGY, Issue 1 2006
    Gwang Hoon Kim
    When the coenocytic green alga Bryopsis plumosa (Huds.) Ag. was cut open and the cell contents were expelled, the cell organelles agglutinated rapidly in seawater to form protoplasts. Aggregation of cell organelles in seawater was mediated by a lectin,carbohydrate complementary system. Two sugars, N -acetyl- d -glucosamine and N -acetyl- d -galactosamine inhibited aggregation of cell organelles. The presence of these sugars on the surface of chloroplasts was verified with their complementary fluorescein isothiacyanate-labeled lectins. An agglutination assay using human erythrocytes showed the presence of lectins specific for N -acetyl- d -galactosamine and N -acetyl- d -glucosamine in the crude extract. One-step column purification using N -acetyl- d -glucosamine-agarose affinity chromatography yielded a homogeneous protein. The protein agglutinated the cell organelles of B. plumosa, and its agglutinating activity was inhibited by the above sugars. Sodium dodecyl sulfate polyacrylamide gel electrophoresis results showed that this protein might be composed of two identical subunits cross-linked by two disulfide bridges. Enzyme and chemical deglycosylation experiments showed that this protein is deficient in glycosylation. The molecular weight was determined as 53.8 kDa by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The N-terminal 15 amino acid sequence of the lectin was Ser,Asp,Leu,Pro,Thr,X,Asp,Phe,Phe,His,Ile,Pro,Glu,Arg,Tyr, and showed no sequence homology to those of other reported proteins. These results suggest that this lectin belongs to a new class of lectins. We named this novel lectin from B. plumosa"bryohealin." [source]


    PYRENOID FORMATION ASSOCIATED WITH THE CELL CYCLE IN THE BROWN ALGA, SCYTOSIPHON LOMENTARIA (SCYTOSIPHONALES, PHAEOPHYCEAE),

    JOURNAL OF PHYCOLOGY, Issue 6 2003
    Chikako Nagasato
    Vegetative cells of the brown alga Scytosiphon lomentaria (Lyngbye) Link characteristically have only one chloroplast with a prominent protruding pyrenoid, whereas zygotes have both paternal and maternal chloroplasts. In zygotes, before cell and chloroplast division, each chloroplast has an old and a new pyrenoid. In this study, we raised a polyclonal antibody to RUBISCO and examined the distribution of RUBISCO by immunofluorescence microscopy, focusing on new pyrenoid formation in vegetative cells of gametophytes and zygotes in Scytosiphon. In interphase, only one old pyrenoid was positively indicated by anti-RUBISCO antibody in vegetative cells of gametophytes. From mid-S phase, small fluorescence aggregates reflecting RUBISCO localization started to appear at stroma positions other than adjacent to the old protruding pyrenoid. The fluorescent spots eventually coalesced into a protrusion into the adjacent cytoplasm. We also used inhibitors to clarify the relationship between the cell cycle and new pyrenoid formation, using zygotes after fertilization. When DNA replication was blocked by aphidicolin, new pyrenoid formation was also inhibited. Washing out aphidicolin permitted new pyrenoid formation with the progression of the cell cycle. When mitosis was prolonged by nocodazole, which disrupted the spindle microtubules, the fluorescent masses indicating RUBISCO localization continued to increase when compared with pyrenoid formation in untreated zygotes. During treatment with chloramphenicol, mitosis and cytokinesis were completed. However, there was no occurrence of new RUBISCO localization within the chloroplast stroma beyond the old pyrenoid. From these observations, it seems clear that new pyrenoid formation in the brown alga Scytosiphon depends on the cell cycle. [source]


    THE IMPACT OF HOMOGENIZATION AND MICROFILTRATION ON RENNET-INDUCED GEL FORMATION

    JOURNAL OF TEXTURE STUDIES, Issue 4 2008
    STEPHAN THOMANN
    ABSTRACT The effects of the independent variables, milk homogenization pressure (p1), concentration factor of milk microfiltration (i) and pH on the rheological properties of rennet milk gels were studied. Nondestructive oscillatory rheometry was used to determine rennet coagulation time (RCT), curd firming rate (CFR) and cutting time (CT). A central composite design, comprising two levels of i (1 and 2), pH (6.4 and 6.6) and p1 (0 and 8 MPa), was applied. Second-order polynomial models successfully described (R2 > 0.92) the relationship between processing parameters and rheological properties of the gels. pH had the most important influence on RCT, while CFR and CT were strongly influenced by i, pH and the interaction of i and pH. In contradiction to studies on active filler interactions for acid milk gels, a discrepancy was observed between results obtained by compression test and rheometry. Rennet gel firmness strongly decreased with a rise in p1 when measured using the compression test, whereby CFR increased with an increase in p1 when measured using rheometry. The latter result corresponds to higher storage modulus values after a certain time indicating higher gel stiffness. This effect was stronger for concentrated milk than for unconcentrated milk. PRACTICAL APPLICATIONS The use of microfiltration (MF) and homogenization may reduce raw material and processing time in conventional cheese manufacture. However, MF markedly influences milk composition, and homogenization alters the particle size distribution of fat globules. Hence, both technologies may influence rennet-induced gel formation, syneresis, cheese composition and quality. Curd firmness of homogenized milk is often too weak to resist the extensive curd treatment applied in semi-hard cheese manufacture which causes loss of curd fines during the syneresis process and finally decreases cheese yield. MF leads to high curd firmness if cutting is not performed at the appropriate time, which unnecessarily extends processing time. The study of the effect of the individual treatments, as well as of the combination of both on rennet-induced gel formation, is the first important step to evaluate their impact on further processing steps in cheese making. The combination of both technologies may overcome the antagonistic effect of the individual technology as low curd firmness due to homogenization can be compensated by MF that increases curd firmness and vice versa. [source]


    IDEOLOGICAL DEVELOPERS AND THE FORMATION OF LOCAL DEVELOPMENT POLICY: THE CASE OF INNER-CITY PRESERVATION IN TEL AVIV

    JOURNAL OF URBAN AFFAIRS, Issue 5 2008
    NURIT ALFASI
    ABSTRACT:,This article studies the role of ideological developers (IDs) in the formation and implementation of local development policy. The IDs are developers whose motivation is ideological as opposed to financial, and they initiate ideas rather than plans and projects. Based on a case study regarding inner-city preservation, we claim that in Tel Aviv, IDs have much leverage on local decision making. The IDs are individuals with high personal capital, who focus on an issue that it is not championed by existing civil groups. As the IDs seek out influential routes to policy makers, they build circumstantial coalitions. Through these limited and conditional partnerships with administrators and other influential actors, the IDs apply pressure and advance their specific cause. [source]


    COALITION FORMATION IN A GLOBAL WARMING GAME: HOW THE DESIGN OF PROTOCOLS AFFECTS THE SUCCESS OF ENVIRONMENTAL TREATY-MAKING

    NATURAL RESOURCE MODELING, Issue 3 2006
    JOHAN EYCKMANS
    ABSTRACT. We combine new concepts of noncooperative coalition theory with an integrated assessment model on climate change to analyze the impact of different protocol designs on the success of coalition formation. We analyze the role of "single versus multiple coalitions,""open versus exclusive membership,""no, weak and strong consensus about membership" and "no transfers versus transfers." First, we want to find out whether and how modifications of the standard assumptions affect results that are associated with the widely applied cartel formation game in the noncooperative game theoretic analysis of international environmental agreements. Second, we discuss normative policy conclusions that emerge from the various modifications. Third, we confront our results with evidence on past international environmental treaties and derive an agenda for future research. [source]


    FUTURES MARKETS AND BUBBLE FORMATION IN EXPERIMENTAL ASSET MARKETS*

    PACIFIC ECONOMIC REVIEW, Issue 2 2006
    Charles Noussair
    In addition to a spot market, there are futures markets in operation, one maturing at the beginning of each period of the life of the asset. We find that when futures markets are present, bubbles do not occur in the spot markets. The futures markets seem to reduce the speculation and the decision errors that appear to give rise to price bubbles in experimental asset markets. [source]


    UNIQUE MANIRAPTORAN EGG CLUTCH FROM THE UPPER CRETACEOUS TWO MEDICINE FORMATION OF MONTANA REVEALS THEROPOD NESTING BEHAVIOUR

    PALAEONTOLOGY, Issue 6 2008
    DARLA K. ZELENITSKY
    Abstract:, Egg clutches of non-avian maniraptoran theropods (Dinosauria) are rare, particularly in North America where those of Troodon formosus are the only maniraptoran clutches known. Here we describe a new partial maniraptoran clutch and nesting trace referred to Montanoolithus strongorum oogen. et oosp. nov. (Montanoolithidae oofam. nov.), from the Upper Cretaceous Two Medicine Formation of Montana. Based on a cladistic analysis of reproductive traits, we infer that this clutch belonged either to a caenagnathid or to a dromaeosaurid, which makes it the first clutch known of either taxon. This specimen preserves impressions and eggshell fragments of at least five eggs on a nest structure. The eggs are asymmetrical, paired, and lay radially in a ring configuration on the sloped sides of a bioturbated, flat-topped sandstone mound. Geology of the locality indicates the female nested in a poorly-vegetated area of freshly deposited sand, possibly near an active river channel. This clutch reveals that the egg-layer of Montanoolithus strongorum had a unique suite of reproductive characteristics and nesting behaviours among maniraptorans. [source]


    PERMIAN OSTRACODS FROM THE LERCARA FORMATION (MIDDLE TRIASSIC,CARNIAN?), SICILY, ITALY

    PALAEONTOLOGY, Issue 3 2008
    SYLVIE CRASQUIN
    Abstract:, A rich, diverse Permian ostracod fauna has been recovered from the red and grey, laminated shales and quartz-rich shales of the Triassic Lercara Formation. Forty-seven species have been identified, 13 of which are newly described here; they belong to 26 genera of which three are new: Anahuacia lercaraensis sp. nov., Aurigerites siciliaensis sp. nov., Bairdia portellaensis sp. nov., Cristanaria? katyae sp. nov., Fabalicypris gruendeli sp. nov., Lethiersa salomonensis gen. et sp. nov., Lethiersia sinusoventralis gen. et sp. nov., Portella trapezoida gen. et sp. nov., Siciliella elongata gen. et sp. nov., Siciliella infernespinosa gen. et sp. nov., Siciliella prima gen. et sp. nov., Siciliella quadrata gen. et sp. nov., and Siciliella spinorobusta gen. et sp. nov. The assemblages contain or are composed of palaeopsychrospheric forms, which are regarded as index fossils for deep environments. The bathymetry of the different associations in life is evaluated. [source]