Pollen record and age determinations of a profile at Cape Mamontov Klyk, Siberia

Non-glaciated Arctic lowlands in north-east Siberia were subjected to extensive landscape and environmental changes during the Late Quaternary. Coastal cliffs along the Arctic shelf seas expose terrestrial archives containing numerous palaeoenvironmental indicators (e.g., pollen, plant macro-fossils and mammal fossils) preserved in the permafrost. The presented sedimentological (grain size, magnetic susceptibility and biogeochemical parameters), cryolithological, geochronological (radiocarbon, accelerator mass spectrometry and infrared-stimulated luminescence), heavy mineral and palaeoecological records from Cape Mamontov Klyk record the environmental dynamics of an Arctic shelf lowland east of the Taymyr Peninsula, and thus, near the eastern edge of the Eurasian ice sheet, over the last 60 Ky. This region is also considered to be the westernmost part of Beringia, the non-glaciated landmass that lay between the Eurasian and the Laurentian ice caps during the Late Pleistocene. Several units and subunits of sand deposits, peat-sand alternations, ice-rich palaeocryosol sequences (Ice Complex) and peaty fillings of thermokarst depressions and valleys were presented. The recorded proxy data sets reflect cold stadial climate conditions between 60 and 50 Kya, moderate inderstadial conditions between 50 and 25 Kya and cold stadial conditions from 25 to 15 Kya. The Late Pleistocene to Holocene transition, including the Allerød warm period, the early to middle Holocene thermal optimum and the late Holocene cooling, are also recorded. Three phases of landscape dynamic (fluvial/alluvial, irregular slope run-off and thermokarst) were presented in a schematic model, and were subsequently correlated with the supraregional environmental history between the Early Weichselian and the Holocene.

Causación y ergatividad en la semántica relacional

En el marco de la gramática contrastiva entre inglés y castellano, asumimos la perspectiva generativista, según la cual la sintaxis humana resulta de procesos derivacionales que combinan, por medio de mecanismos innatos, elementos capaces de codificar significados primitivos. Trabajamos con datos, ya sea reales o inventados, que ilustran los distintos tipos de oraciones ?gramaticales? posibles en una lengua natural. Nos centramos en la noción de ?ergatividad?, utilizada por distintas teorías para explicar fenómenos sintácticos y semánticos no siempre coincidentes. Desde el Funcionalismo/Cognitivismo norteamericano, Scott DeLancey (2001) compara distintas lenguas y distingue morfológicamente los sujetos ?agentivos? en estructuras causadas de los sujetos ?afectados? en estructuras no causadas. Según la Lingüística Sistémica Funcional (Halliday 1985, 2004), la ergatividad abarca, no sólo la presencia o ausencia de Causa en un proceso particular, sino también la relación causal que vincula distintos procesos entre sí. El esquema ergativo de Halliday incluye, además de pares constituidos por eventos de cambio de estado no causados y de causa externa, eventos inergativos de causa externa, y eventos transitivos instigados por otro proceso, expresado lingüísticamente o bien inferido. Desde la perspectiva de la Semántica Relacional (Mateu, 2002), reducimos el número de ?constructos primitivos? disponibles de tres a dos. Consideramos dos alternancias: la ergativo-transitiva y la causa interna/externa con inergativos. No vinculamos ni sintáctica ni derivacionalmente las construcciones transitivas con los eventos inferidos que las instigan. Justificamos la relación derivacional que vincula las construcciones pasivas estáticas con las construcciones ergativas de verbos naturalmente alternantes, por un lado, y, con las construcciones transitivas de verbos de ?locatum? y de inergativos, por el otro. Reanalizamos, respecto de la bibliografía canónica, la naturaleza del clítico ?se? en las construcciones ergativas españolas. Este análisis orienta de manera teórica el abordaje de las construcciones pertinentes, y ofrece equivalencias posibles que pueden resultar útiles para la traducción

Causación y ergatividad en la semántica relacional

En el marco de la gramática contrastiva entre inglés y castellano, asumimos la perspectiva generativista, según la cual la sintaxis humana resulta de procesos derivacionales que combinan, por medio de mecanismos innatos, elementos capaces de codificar significados primitivos. Trabajamos con datos, ya sea reales o inventados, que ilustran los distintos tipos de oraciones ?gramaticales? posibles en una lengua natural. Nos centramos en la noción de ?ergatividad?, utilizada por distintas teorías para explicar fenómenos sintácticos y semánticos no siempre coincidentes. Desde el Funcionalismo/Cognitivismo norteamericano, Scott DeLancey (2001) compara distintas lenguas y distingue morfológicamente los sujetos ?agentivos? en estructuras causadas de los sujetos ?afectados? en estructuras no causadas. Según la Lingüística Sistémica Funcional (Halliday 1985, 2004), la ergatividad abarca, no sólo la presencia o ausencia de Causa en un proceso particular, sino también la relación causal que vincula distintos procesos entre sí. El esquema ergativo de Halliday incluye, además de pares constituidos por eventos de cambio de estado no causados y de causa externa, eventos inergativos de causa externa, y eventos transitivos instigados por otro proceso, expresado lingüísticamente o bien inferido. Desde la perspectiva de la Semántica Relacional (Mateu, 2002), reducimos el número de ?constructos primitivos? disponibles de tres a dos. Consideramos dos alternancias: la ergativo-transitiva y la causa interna/externa con inergativos. No vinculamos ni sintáctica ni derivacionalmente las construcciones transitivas con los eventos inferidos que las instigan. Justificamos la relación derivacional que vincula las construcciones pasivas estáticas con las construcciones ergativas de verbos naturalmente alternantes, por un lado, y, con las construcciones transitivas de verbos de ?locatum? y de inergativos, por el otro. Reanalizamos, respecto de la bibliografía canónica, la naturaleza del clítico ?se? en las construcciones ergativas españolas. Este análisis orienta de manera teórica el abordaje de las construcciones pertinentes, y ofrece equivalencias posibles que pueden resultar útiles para la traducción

Causación y ergatividad en la semántica relacional

En el marco de la gramática contrastiva entre inglés y castellano, asumimos la perspectiva generativista, según la cual la sintaxis humana resulta de procesos derivacionales que combinan, por medio de mecanismos innatos, elementos capaces de codificar significados primitivos. Trabajamos con datos, ya sea reales o inventados, que ilustran los distintos tipos de oraciones ?gramaticales? posibles en una lengua natural. Nos centramos en la noción de ?ergatividad?, utilizada por distintas teorías para explicar fenómenos sintácticos y semánticos no siempre coincidentes. Desde el Funcionalismo/Cognitivismo norteamericano, Scott DeLancey (2001) compara distintas lenguas y distingue morfológicamente los sujetos ?agentivos? en estructuras causadas de los sujetos ?afectados? en estructuras no causadas. Según la Lingüística Sistémica Funcional (Halliday 1985, 2004), la ergatividad abarca, no sólo la presencia o ausencia de Causa en un proceso particular, sino también la relación causal que vincula distintos procesos entre sí. El esquema ergativo de Halliday incluye, además de pares constituidos por eventos de cambio de estado no causados y de causa externa, eventos inergativos de causa externa, y eventos transitivos instigados por otro proceso, expresado lingüísticamente o bien inferido. Desde la perspectiva de la Semántica Relacional (Mateu, 2002), reducimos el número de ?constructos primitivos? disponibles de tres a dos. Consideramos dos alternancias: la ergativo-transitiva y la causa interna/externa con inergativos. No vinculamos ni sintáctica ni derivacionalmente las construcciones transitivas con los eventos inferidos que las instigan. Justificamos la relación derivacional que vincula las construcciones pasivas estáticas con las construcciones ergativas de verbos naturalmente alternantes, por un lado, y, con las construcciones transitivas de verbos de ?locatum? y de inergativos, por el otro. Reanalizamos, respecto de la bibliografía canónica, la naturaleza del clítico ?se? en las construcciones ergativas españolas. Este análisis orienta de manera teórica el abordaje de las construcciones pertinentes, y ofrece equivalencias posibles que pueden resultar útiles para la traducción

High-pressure adsorption capacity and structure of CO2 in carbon slit pores: Theory and simulation

We present new simulation results for the packing of single-center and three-center models of carbon dioxide at high pressure in carbon slit pores. The former shows a series of packing transitions that are well described by our density functional theory model developed earlier. In contrast, these transitions are absent for the three-center model. Analysis of the simulation results shows that alternations of flat-lying molecules and rotated molecules can occur as the pore width is increased. The presence or absence of quadrupoles has negligible effect on these high-density structures.

Plaid motion rivalry: Correlates with binocular rivalry and positive mood state

Recently Hupe and Rubin (2003, Vision Research 43 531 - 548) re-introduced the plaid as a form of perceptual rivalry by using two sets of drifting gratings behind a circular aperture to produce quasi-regular perceptual alternations between a coherent moving plaid of diamond-shaped intersections and the two sets of component 'sliding' gratings. We call this phenomenon plaid motion rivalry (PMR), and have compared its temporal dynamics with those of binocular rivalry in a sample of subjects covering a wide range of perceptual alternation rates. In support of the proposal that all rivalries may be mediated by a common switching mechanism, we found a high correlation between alternation rates induced by PMR and binocular rivalry. In keeping with a link discovered between the phase of rivalry and mood, we also found a link between PMR and an individual's mood state that is consistent with suggestions that each opposing phase of rivalry is associated with one or the other hemisphere, with the 'diamonds' phase of PMR linked with the 'positive' left hemisphere.

Understanding U.S. regional linguistic variation with Twitter data analysis

We analyze a Big Data set of geo-tagged tweets for a year (Oct. 2013–Oct. 2014) to understand the regional linguistic variation in the U.S. Prior work on regional linguistic variations usually took a long time to collect data and focused on either rural or urban areas. Geo-tagged Twitter data offers an unprecedented database with rich linguistic representation of fine spatiotemporal resolution and continuity. From the one-year Twitter corpus, we extract lexical characteristics for twitter users by summarizing the frequencies of a set of lexical alternations that each user has used. We spatially aggregate and smooth each lexical characteristic to derive county-based linguistic variables, from which orthogonal dimensions are extracted using the principal component analysis (PCA). Finally a regionalization method is used to discover hierarchical dialect regions using the PCA components. The regionalization results reveal interesting linguistic regional variations in the U.S. The discovered regions not only confirm past research findings in the literature but also provide new insights and a more detailed understanding of very recent linguistic patterns in the U.S.

A gazdasági teljesítmények vállalkozási mérettől függő jellemzői Magyarországon = Changing ownership and business structures in the Hungarian economy

A mögöttünk hagyott két évtizedben – tetszik, vagy sem – a magyar gazdaság 1992. évi mélypontról történő kilábalásában, majd új növekedési pályára állásában meghatározó szerepe volt a hazai forrásokat kiegészítő külföldi befektetéseknek. Ennek természetesen ára volt: a tevékenységi struktúra (termékszerkezet) módosulása, a tulajdonosi összetétel radikális átalakulása, a külgazdasági kapcsolatok irányultságának változása, a lakosság önfoglalkoztatási célú vállalkozásainak szaporodása, a gazdaságfejlesztés irányának és ütemének cikk-cakkos mozgása, az állami szerepkör fokozatos leépülése. Írásunk célja annak áttekintése, hogy a nemzetközi tőkeáramlás tendenciáinak módosulását követően – a Magyarországra érkező külföldi tőkebefektetések jelentős csökkenéséből fakadóan – a kizárólagos és többségi hazai tulajdonú szereplők (kiemelten a hazai közép- és kisvállalkozások) milyen mértékben lehetnek alkalmasak a kieső teljesítmények pótlására, illetve a gazdasági válság lecsengését követően milyen ütemű növekedést képesek biztosítani a magyar gazdaság számára. A válaszok nagy valószínűséggel az Új Széchenyi Terv szempontjából sem közömbösek. Az írást a szerkesztőség vitairatnak szánja és szívesen ad teret a témával kapcsolatos vélemények kifejtésének. / === / The economic performance during the transition period was characterized by the alternations of fulfilled hopes and unrealized expectations. The economic restructuring and changes in market relations took place during the first decade, while new – mostly foreign – investment groups entered the new market. As a result the economy was stabilized and was put on a new growth path. But after the millennium the foreign investment based economy development strategy was no more adequate. The new engine for the growth should have been the domestic small and medium enterprise sector (SME), but despite the subsidies this sector was not strengthened enough to take this role.

Gazdasági kórkép alulnézetből I. rész (Syndrome of Hungarian Economy from Bottom-view – I. part)

A rendszerváltás utáni időszak gazdasági teljesítményei a beteljesült remények és a megvalósulatlan várakozások egymást követő hullámzásait takarják. A mögöttünk hagyott két évtized első felét a gazdasági szerkezetváltás, a piaci kapcsolatok módosulása, valamint új – többségében külföldi – befektetői csoportok megjelenése jellemezte, amelyek együttes hozadéka volt a gazdaság stabilizálódása, majd az új növekedési pályára állás. Az ezredfordulót követő évtized első felére azonban a külföldi befektetésekre alapozott gazdaságfejlesztési stratégia erejét vesztette, s a helyettesítésre szánt hazai kkv-szektor – a kiemelt támogatások és a kedvezmények ellenére – nem tudott a növekedés motorjává válni. Szerzőnk – a BCE tudományos kutatója és az APEH korábbi elnöke – a versenyszektor 2000–2008. évi pénzügyi beszámolói alapján a hazai vállalkozások demográfiai, teljesítményi és eredményességi jellemzőit vizsgálja, s két részből álló tanulmányában arra keresi a választ, hogy a várakozásoktól elmaradó működési eredményekben milyen szerepe lehet a gazdaságfejlesztési stratégia hiányának, a vállalkozási teljesítmények elégtelenségének, a tőkehiánynak, illetve a pénzügyi rendszer torzulásainak. Szerkesztőségünk a tanulmányt olyan vitaindítónak tekinti, ami széles érdeklődésre tarthat számot, s szívesen vállalkozunk arra, hogy közreadunk minden jobbító szándékú gondolatot. _______ The economic performance during the transition period was characterized by the alternations of fulfilled hopes and unrealized expectations. The economic restructuring and changes in market relations took place during the first decade, while new – mostly foreign – investment groups entered on the new market. As a result the economy was stabilized and was put to a new growth path. But after the millennium the foreign investment based economy development strategy was no more adequate. The new engine for the growth should have been the domestic small and medium enterprise sector (SME), but despite the subsidies this sector was not strengthened to take this role. The author – the researcher of BCE, and the ex-president of APEH – analyses the characteristics of the domestic business demography, performance and effectiveness, based on the 2000–2008 annual financial statements of the business sector. The two-part study seeks the reason for the disappointing operation results. What role take in this phenomena the absence of economic strategy, the deficiency of business performance, the lack of capital and the financial distortions of the system. Our editorial intend this study as a debate for the public, and we would publish the ideas which improves this relevant topic.

Gazdasági kórkép alulnézetből 2. rész (Syndrome of Hungarian Economy from Bottom-view - part 2.)

A magyar gazdaság új növekedési pályára állása a kilencvenes évek végére tehető, s ebben meghatározó szerepe volt a pótlólagos erőforrásként szolgáló külföldi működőtőke-befektetéseknek. A nemzetközi tőkeáramlás ezredfordulót követő módosulása (csökkenő volumen, változó irányultság) kedvezőtlenül érintette a hazai gazdaságot, aminek egyik következménye a beruházások csökkenése és a növekedési ütem lassulása, másik következménye viszont – a jövedelemkiáramlást semlegesítő hatás elmaradása miatt – a fizetési mérleg romlása. Ebben a helyzetben halaszthatatlanná vált az államháztartási egyensúlyromlás megállítása, illetve a gazdasági fejlődés új alapokra helyezése. A szerző elemzésében – a hazai versenyszektor eredményességi és vagyoni jellemzőinek értékelésével – azt szeretné jelezni, hogy az egyensúlytalansági állapot megszüntetése nem szorítkozhat az államháztartási rendszerre, vagyis az ország helyzetének stabilizálása, majd új növekedési pályára állás nem képzelhető el a gazdaság átfogó modernizációja nélkül. Vizsgálata a ténylegesen működő (343 ezer) hazai társas vállalkozás 2000–2008. évi pénzügyi beszámolóinak adataira épül. Álláspontja szerint a mintavétel nagysága ellensúlyozza az esetleges torzító hatásokat (lásd: helyenként előforduló kreatív beszámolók), így a vállalkozások mennyiségi gyarapodása, méret szerinti megoszlása, a gazdasági tevékenység jellege, a teljesítmények és eredmények alakulása, a vállalkozói vagyon módosulása megbízhatóan értékelhető, illetve a tapasztalatok alapján a korrekciós intézkedések igénye és azok tartalma is jól körvonalazható. Tanulmányát így ajánljuk a téma iránt érdeklődőknek, a versenyszektor szereplőinek, de leginkább a gazdaságpolitika formálóinak. _________ The economic performance during the transition period was characterized by the alternations of fulfilled hopes and unrealized expectations. The economic restructuring and changes in market relations took place during the first decade, while new – mostly foreign – investment groups entered on the new market. As a result the economy was stabilized and was put to a new growth path. But after the millennium the foreign investment based economy development strategy was no more adequate. The new engine for the growth should have been the domestic small and medium enterprise sector (SsME), but despite the subsidies this sector was not strengthened to take this role. The author – the researcher of BCE, and the ex-president of APpEH – analyses the characteristics of the domestic business demography, performance and effectiveness, based on the 2000–2008 annual financial statements of the business sector. In the author’s analysis – with assessment of the domestic business sector and financial performance characteristicst - he would like to point out that the imbalance can not be confined to the elimination of state government system, that is, the country’s situation to stabilize, and then post a new growth path is not conceivable without the modernization of the economy overall. In his view, the sample size outweighed the possible distortionary effects (see occurring in places of creative accounts), so the growth of business volume, size distribution, the nature of economic activity, the evolution of performance and results, a reliable assessment of changes in the business of property and the experience on the basis of the need for corrective action, and its contents are also well delineated. Sstudy it is recommended for those interested in the topic, the business sector actors, but most of the economic policy makers.

Understanding Ten-Eleven Translocation-2 in Hematological and Nervous Systems

I proposed the study of two distinct aspects of Ten-Eleven Translocation 2 (TET2) protein for understanding specific functions in different body systems. In Part I, I characterized the molecular mechanisms of Tet2 in the hematological system. As the second member of Ten-Eleven Translocation protein family, TET2 is frequently mutated in leukemic patients. Previous studies have shown that the TET2 mutations frequently occur in 20% myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN), 10% T-cell lymphoma leukemia and 2% B-cell lymphoma leukemia. Genetic mouse models also display distinct phenotypes of various types of hematological malignancies. I performed 5-hydroxymethylcytosine (5hmC) chromatin immunoprecipitation sequencing (ChIP-Seq) and RNA sequencing (RNA-Seq) of hematopoietic stem/progenitor cells to determine whether the deletion of Tet2 can affect the abundance of 5hmC at myeloid, T-cell and B-cell specific gene transcription start sites, which ultimately result in various hematological malignancies. Subsequent Exome sequencing (Exome-Seq) showed that disease-specific genes are mutated in different types of tumors, which suggests that TET2 may protect the genome from being mutated. The direct interaction between TET2 and Mutator S Homolog 6 (MSH6) protein suggests TET2 is involved in DNA mismatch repair. Finally, in vivo mismatch repair studies show that the loss of Tet2 causes a mutator phenotype. Taken together, my data indicate that TET2 binds to MSH6 to protect genome integrity. In Part II, I intended to better understand the role of Tet2 in the nervous system. 5-hydroxymethylcytosine regulates epigenetic modification during neurodevelopment and aging. Thus, Tet2 may play a critical role in regulating adult neurogenesis. To examine the physiological significance of Tet2 in the nervous system, I first showed that the deletion of Tet2 reduces the 5hmC levels in neural stem cells. Mice lacking Tet2 show abnormal hippocampal neurogenesis along with 5hmC alternations at different gene promoters and corresponding gene expression downregulation. Through the luciferase reporter assay, two neural factors Neurogenic differentiation 1 (NeuroD1) and Glial fibrillary acidic protein (Gfap) were down-regulated in Tet2 knockout cells. My results suggest that Tet2 regulates neural stem/progenitor cell proliferation and differentiation in adult brain.

(Table S1) Age determination of Atlantic Ocean sediment cores

Well-dated benthic foraminifer oxygen isotopic records (d18O) from different water depths and locations within the Atlantic Ocean exhibit distinct patterns and significant differences in timing over the last deglaciation. This has two implications: on the one hand, it confirms that benthic d18O cannot be used as a global correlation tool with millennial-scale precision, but on the other hand, the combination of benthic isotopic records with independent dating provides a wealth of information on past circulation changes. Comparing new South Atlantic benthic isotopic data with published benthic isotopic records, we show that (1) circulation changes first affected benthic d18O in the 1000-2200 m range, with marked decreases in benthic d18O taking place at ~17.5 cal. kyr B.P. (ka) due to the southward propagation of brine waters generated in the Nordic Seas during Heinrich Stadial 1 (HS1) cold period; (2) the arrival of d18O-depleted deglacial meltwater took place later at deeper North Atlantic sites; (3) hydrographic changes recorded in North Atlantic cores below 3000 m during HS1 do not correspond to simple alternations between northern- and southern-sourced water but likely reflect instead the incursion of brine-generated deep water of northern as well as southern origin; and (4) South Atlantic waters at ~44°S and ~3800 m depth remained isolated from better-ventilated northern-sourced water masses until after the resumption of North Atlantic Deep Water (NADW) formation at the onset of the Bølling-Allerod, which led to the propagation of NADW into the South Atlantic.

Sediment rates and structures in Bay of Kiel, Baltic Sea

Density and diversity of bottom fauna population as dependent on sediment types and water depth is largely well known in Kiel Bay. This is in contrast to structures and processes of bioturbation, although generally it has a big influence on the benthic boundary layer and its processes, e.g., the metabolism of the bottom fauna, the mechanical properties, the age dating, and the large field of chemical processes. In the densely inhabited sands and muddy sands of the shallower waters with sediment thicknesses of some decimeters only, bioturbation is usually ubiquitous, and most of the structures left are monotonously of "biodeformational" character. At greater water depths, however, where a sedimentary column of several meters of Holocene is developed, the X-ray radiographs of numerous sediment cores show heterogeneous biogenic structures with regional and stratigraphical differentiation. They are described in terms of ichnofabrics and are interpreted on ethological knowledge of the related macrobenthos species. lmportant organisms creating specific traces include the bivalve Arctica (Cyprina) islandica and the polychaete worm Pectinaria koreni. These species are abundant in Kiel Bay and produce by their crawling-plowing mode of locomotion, a characteristic biogenic stratification, the "plow-sole structure". Other typical biogenic structures are tube traces, which are left by a number of different polychaetes occurring either singly, or as U-pairs mainly in mud sediments. Although sea urchins are rare to absent in Kiel Bay, layers of their characteristic traces Scolicia occur as witness of paleohydrographic events in channel sediments of the central bay. Plow-sole traces, polychaete-tube ichnofabric, Scolicia layers and alternations of laminated and bioturbated layers are considered as building blocks of a future "ichnostratigraphy" of Kiel Bay.

Argument structure and specific language impairment: retrospect and prospect

This article reflects a collaboration between the Universities of Groningen and Reading of which Frans Zwarts was the promoter. One of the outcomes was a close attention to the learning of various aspects of argument structure by children with specific language impairment (SLI) in Dutch and English. At that time and since, the focus on deficits in grammatical morphology in these children has left verb complementation as something of a syntactic Cinderella. Here we review the findings from our studies in the 1990s. We confirm that children with SLI in both languages have problems with verb specificity, with argument structure alternations and with resultative verb predicates. The very limited number of subsequent studies on verb syntax appear to support our findings. We conclude that this is an area which will repay further scrutiny – it is high time argument structure received an invitation to the ball.

(Table 2) Terrigenous, authigenic and biogenic composition of sediments at DSDP Hole 93-603B

Pelagic sedimentation during the Early Cretaceous at Site 603 produced alternations of laminated marly limestone and bioturbated limestone-a facies typical of the "Blake-Bahama Formation" of the western Atlantic. This limestone is a nannofossil micrite, rich in calcified radiolarians, with variable amounts of organic matter, pyritized radiolarian tests, fish debris, and micaceous silt. The laminated marly limestone layers are enriched in organic matter when compared with the intervals of bioturbated limestone. The organic carbon is predominantly terrestrial plant debris; where the organic-carbon content is in excess of 1%, there is also a significant marine-derived component. Laminations can result either from bands of alternately enriched and depleted opaque material and clay, or from bands of elongate lenses (microflasers) of micrite, which could be plastically deformed pellets or diagenetic features. The alternating intervals of laminated and bioturbated structures may have resulted from combined changes in surface productivity, in the influx of terrigenous organic matter, and in the intensity of bottom circulation, which led to episodic oxygen depletion in the bottom water and sediments. Variations in the relative proportions of laminated clay-rich and bioturbated lime-rich limestone and in the development of cycles between these structures make it possible to subdivide the Lower Cretaceous pelagic facies into several subunits which appear to be regional in extent. Bioturbated limestone is dominant in the Berriasian, laminated marly limestone in the Valanginian and Barremian-lower Aptian, and well-developed alternations between these end members in the Hauterivian. The Hauterivian to lower Aptian sediments contain abundant terrigenous clastic turbidites associated with a submarine fan complex. These changes in the general characteristics of the pelagic sediment component of the Blake-Bahama Formation at Site 603 are synchronous with those in the Blake-Bahama Basin (Sites 534 and 391) to the south. Carbonate sedimentation ended in the early Aptian, probably because of a regional shoaling of the carbonate compensation depth.