Late Miocene biogeography and paleoclimatology of the central North Atlantic

Quantitative analyses of planktonic foraminiferal assemblages from Deep Sea Drilling Project (DSDP) Holes 334 and 410 demonstrate that subpolar and subtropical faunal provinces existed in the North Atlantic during the late Miocene. Climatic oscillations are clearly recorded in Hole 410 by variations in abundance of the Neogloboquadrina subpolar assemblage. These climatic oscillations have a period of about 1 m.y. Higher frequency oscillations with a periodicity of one to several hundred thousand years are evident from about 6.5 to 7.5 m.y. and are probably present throughout the entire late Miocene.A revised age of 7.0 m.y. is proposed for the first occurrence of the calcareous nannofossil Amaurolithus primus (the Amaurolithus datum).     

Benthic foraminifera off West Africa (1°N to 32°S): Do live assemblages from the topmost sediment reliably record environmental variability?

Recent benthic foraminifera (> 125 μm) were investigated from multicorer samples on a latitudinal transect of 20 stations between 1°N and 32°S along the upper slope off West Africa. Samples were selected from a narrow water depth interval, between 1200 and 1500 m, so that changes in water masses are minimized, but changes in surface productivity are important and the only significant environmental variable. Live (Rose Bengal stained) benthic foraminifera were counted from the surface sediment down to a maximum of 12 cm. Dead foraminifera were investigated in the top 5 cm of the sediment only. Five live and five dead benthic foraminiferal assemblages were identified using Q-mode principal component analysis, matching distinct primary productivity provinces, characterized by different systems of seasonal and permanent upwelling. Differences in seasonality, quantity, and quality of food supply are the main controlling parameters on species composition and distribution of the benthic foraminiferal faunas.To test the sensitivity of foraminiferal studies based on the uppermost centimeter of sediment only, a comparative Q-mode principal component analysis was conducted on live and dead foraminiferal data from the top 1 cm of sediment. It has been demonstrated that, on the upper slope off West Africa, most of the environmental signals as recorded by species composition and distribution of the “total” live and dead assemblages, i.e., including live and dead foraminifera from the surface sediment down to 12 cm and 5 cm, respectively, can be extracted from the assemblages in the top centimeter of sediment only. On the contrary, subsurface abundance maxima of live foraminifera and dissolution of empty tests strongly bias quantitative approaches based on the calculation of standing stocks and foraminiferal numbers in the topmost centimeter.     

Southern Ocean Pleistocene calcareous nannofossil events: calibration with isotope and geomagnetic stratigraphies

Several cores recovered from the northern belt of the Southern Ocean were analysed to study the Pleistocene calcareous nannofossil records. Calcareous nannofossil events previously described in medium and low latitudes were identified and calibrated with the oxygen isotope and geomagnetic time scales. Although sedimentation rates, hiatuses and degree of calcareous nannofossil preservation sometimes prevent the identification and/or accurate calibration of some of these events, a useful stratigraphic framework was obtained. The possibility of using these calibrated events from high to low latitudes facilitates correlations and should facilitate isotope event identification in a region with low temperature, where calcareous plankton stratigraphies are in general restricted. In general, Pleistocene southern high latitude calcareous nannofossil events show synchronism with those observed in warm and temperate surficial waters. Small discrepancies in the assigned ages are sometimes related to low sampling resolution due to low sedimentation rates. The first occurrence (FO) of Emiliania huxleyi and the last occurrence (LO) of Pseudoemiliania lacunosa are observed in Marine Isotope Stages (MIS) 8 and 12, respectively. A reversal in abundance between Gephyrocapsa muellerae and E. huxleyi is observed close to the MIS 4/5 boundary. MIS 6 is characterised by an increase in G. muellerae and MIS 7 features a dramatic decrease in the proportion of Gephyrocapsa caribbeanica. This latter species began to increase its proportions from the MIS 13/14 boundary to MIS13, showing diachronism between the different sites. The LO of Reticulofenestra asanoi is observed at MIS 22, confirming this event as a global synchronous reference datum. By contrast, the FO of R. asanoi occurs at MIS 35 and is diachronous with the existing data from other oceanic regions. A re-entry of medium sized Gephyrocapsa (3–5 μm maximum diameters) can be identified in some cores close to MIS 25; although the low abundance of this taxon prevents an accurate calibration, it may be concluded that this event is diachronous as compared with the existing low-latitude data. The LO of large morphotypes of Gephyrocapsa is well correlated with MIS 37, showing synchronism with other oceanic regions, whereas the FO of this species is not well calibrated due to the absence of age-control points.     

Food supply to the seafloor in the Pacific Ocean after the Cretaceous/Paleogene boundary event

Deep-sea benthic foraminifera show important but transient assemblage changes at the Cretaceous/Paleogene (K/Pg) boundary, when many biota suffered severe extinction. We quantitatively analyzed benthic foraminiferal assemblages from lower bathyal–upper abyssal (1500–2000 m) northwest Pacific ODP Site 1210 (Shatsky Rise) and compared the results with published data on assemblages at lower bathyal (~ 1500 m) Pacific DSDP Site 465 (Hess Rise) to gain insight in paleoecological and paleoenvironmental changes at that time.At both sites, diversity and heterogeneity rapidly decreased across the K/Pg boundary, then recovered. Species assemblages at both sites show a similar pattern of turnover from the uppermost Maastrichtian into the lowermost Danian: 1) The relative abundance of buliminids (indicative of a generally high food supply) increases towards the uppermost Cretaceous, and peaks rapidly just above the K/Pg boundary, coeval with a peak in benthic foraminiferal accumulation rate (BFAR), a proxy for food supply. 2) A peak in relative abundance of Stensioeina beccariiformis, a cosmopolitan form generally more common at the middle than at the lower bathyal sites, occurs just above the buliminid peak. 3) The relative abundance of Nuttallides truempyi, a more oligotrophic form, decreases at the boundary, then increases above the peak in Stensioeina beccariiformis. The food supply to the deep sea in the Pacific Ocean thus apparently increased rather than decreased in the earliest Danian. The low benthic diversity during a time of high food supply indicates a stressed environment. This stress might have been caused by reorganization of the planktic ecosystem: primary producer niches vacated by the mass extinction of calcifying nannoplankton may have been rapidly (<10 kyr) filled by other, possibly opportunistic, primary producers, leading to delivery of another type of food, and/or irregular food delivery through a succession of opportunistic blooms.The deep-sea benthic foraminiferal data thus are in strong disagreement with the widely accepted hypothesis that the global deep-sea floor became severely food-depleted following the K/Pg extinction due to the mass extinction of primary producers (“Strangelove Ocean Model”) or to the collapse of the biotic pump (“Living Ocean Model”).     

Radiolarian faunal turnover across the Oligocene/Miocene boundary in the equatorial Pacific Ocean

The global warming trend of the latest Oligocene was interrupted by several cooling events associated with Antarctic glaciations. These cooling events affected surface water productivity and plankton assemblages. Well-preserved radiolarians were obtained from upper Oligocene to lower Miocene sediments at Ocean Drilling Program (ODP) Leg 199 Sites 1218 and 1219 in the equatorial Pacific, and 110 radiolarian species were identified.Four episodes of significant radiolarian faunal changes were identified: middle late Oligocene (27.5 to 27.3 Ma), latest Oligocene (24.4 Ma), earliest Miocene (23.3 Ma), and middle early Miocene (21.6 Ma). These four episodes approximately coincide with increases and decreases of biogenic silica accumulation rates and increases in δ¹⁸O values coded as “Oi” and “Mi” events. These data indicate that Antarctic glaciations were associated with change of siliceous sedimentation patterns and faunal changes in the equatorial Pacific.Radiolarian fauna was divided into three assemblages based on variations in radiolarian productivity, species richness and the composition of dominant species: a late Oligocene assemblage (27.6 to 24.4 Ma), a transitional assemblage (24.4 to 23.3 Ma) and an early Miocene assemblage (23.3 to 21.2 Ma). The late Oligocene assemblage is characterized by relatively high productivity, low species richness and four dominant species of Tholospyris anthophora, Stichocorys subligata, Lophocyrtis nomas and Lithelius spp. The transitional assemblage represents relatively low values of productivity and species richness, and consists of three dominant species of T. anthophora, S. subligata and L. nomas. The characteristics of the early Miocene assemblage are relatively low productivity, but high species richness. The two dominant species present in this assemblage are T. anthophora and Cyrtocapsella tetrapera. The most significant faunal turnover of radiolarians is marked at the boundary between the transitional/early Miocene assemblages.We also reviewed changes in other microfossil assemblages in the low latitudes during the late Oligocene through early Miocene. The microfossil assemblages of major groups show sequential changes near the Oligocene/Miocene (O/M) boundary (23.8 Ma). Many extinction events and some first occurrences of calcareous nannofossils and many occurrences of radiolarians are found from about 24.8 to 23.3 Ma, and first occurrences of planktic foraminifers and diatoms followed from 23.2 through 22 Ma. Hence, the O/M boundary is identified as a significant level for microfossil evolutions.     

Quantitative characteristic of the catalytic properties and microstructure of cross-linked enzyme aggregates of penicillin acylase

The microstructure and the catalytic properties of cross-linked enzyme aggregates (CLEA) of penicillin acylase (PA) obtained under different conditions were investigated. The period of time left between the enzyme precipitation and the cross-linking step was found to influence the structural organization of the resulting enzyme preparation. Confocal fluorescent microscopy of the so-called “fresh” and “mature” CLEAs PA allowed to estimate the “characteristic” diameter of CLEA PA particles, which appeared to be about 1.6 μm, and revealed that the “mature” type was composed of relatively big particles as compared to the “fresh” type. Complementary kinetic studies showed that the “mature” CLEA PA were more effective in both hydrolytic and synthetic reactions. It was suggested that the aggregate size might regulate the extent of covalent modification of PA and thereby influence the catalytic properties of CLEA.     

Biostratigraphy and paleoceanographic significance of Paleocene radiolarians from offshore eastern New Zealand

A 100-m-thick Paleocene sequence of mainly pelagic sediments at ODP Site 1121, on the eastern flanks of the Campbell Plateau, contains few to common radiolarians of relatively low diversity in the lower 40 m (Early to early Late Paleocene) and abundant, diverse radiolarian assemblages in the upper 60 m (mid-Late Paleocene). The 150 taxa recorded from the entire Paleocene interval are thought to under-represent the actual species diversity by at least one half as many morphotypes have not been differentiated below the level of genus. Assemblages in the lower 40 m are similar to those described from onland New Zealand and DSDP Site 208 (northern Lord Howe Rise); they are correlated with South Pacific radiolarian zones RP4 and RP5. Assemblages in the upper 60 m differ from other known Late Paleocene assemblages in the great abundance of plagiacanthids and cycladophorids. Similarities are noted with later Cenozoic cool-water assemblages. This upper interval is correlated with South Pacific zone RP6, as revised herein, based on comparison with faunas from Site 208 and Marlborough, New Zealand. The interval is also correlated with the upper part of North Atlantic zone RP6 (RP6b–c) based on the presence of Aspis velutochlamydosaurus, Plectodiscus circularis and Pterocodon poculum. Other species, such as Buryella tetradica and Buryella pentadica, are valuable for local correlation but exhibit considerable diachroneity between the Pacific, Indian and Atlantic Oceans. An age model for the Paleocene interval at Site 1121, based on well-constrained nannofossil and radiolarian datums, indicates that the rate of compacted sediment accumulation doubles from 15 to 30 mm/ka at the RP5/RP6 zonal boundary. In large part this is due to a sudden and pronounced increase in accumulation rates for all siliceous fossils; radiolarians and larger diatoms increase from <100 to >10 000 specimens/cm²/ka. This apparent increase in biosiliceous productivity is age-equivalent to a mid-Paleocene cooling event (57–59 Ma) identified from global stable isotope records that is associated with the heaviest δ¹³C values for the entire Cenozoic.     

“Harpoon” Model for Cell–Cell Adhesion and Recognition of Target Cells by the Natural Killer Cells

The mechanism of recognition by natural killer (NK) cells is still unknown. A dynamic model is formulated describing recognition or NK-sensitive target cells (TCs) by NK cells of NK-like cells. This model does not assume the presence of the specific NK-receptor(s) on the membrane of NK cells and corresponding specific ligands on the NK-sensitive TCs. We suggest: (1) the expression of various kinds of “non-NK receptors” and corresponding ligands (counter-receptors) on the plasma membrane of the same NK cell and, possibly, of TCs (e.g. LFA-1 and ICAM-1-ICAM3, CD2 and LFA-3; receptors for TNF and corresponding ligand etc.); (2) the presence of multiple disorders in the organization of “extracellular matrix-surface membrane-submembrane cytoskeleton” assembly of the NK-sensitive TCs; (3) non-specific primary linking of NK cell with TCs, which induces a transfer of vesicles or membrane fragments from the NK surface to the target cell surface (and perhaps vice versa). These processes may also permit the transfer of many types of receptor and counter-receptor molecules from the surface of one conjugated cell to another by vesicles or membrane fragments. After transferral through the intercellular cleft, the free receptors and counter-receptors will be localized on both cell surfaces at the contact region between conjugated cells. By this model the NK cell can “harpoon” the TC and enhance the binding forces between cells up to the critical level and then switch on killing mechanisms for the TC. By means of this “harpoon” model of cell recognition, it seems possible to explain the nature of the wide polymorphism of TCs which are sensitive to the effect of NK and NK-like cells. A mathematical model of the NK cell cytotoxic reaction is described. The model describes many nonlinear peculiarities of the cytotoxic process and predicts some new phenomena. We suggest new approaches of manipulation of cell membranes which can transform NK-resistant target cells in NK sensitive cells and vice versa.     

Vertical Distribution of Radiolarians and Their Role in Epipelagic Communities of the East Pacific Rise and the Gulf of California

Vertical distribution of different groups of radiolarians and mesozooplankton (l = 0.2–3.0 mm) and the contribution of radiolarians to total biomass of bathometer-sampled zooplankton were studied in the epipelagic East Pacific Rise and the Gulf of California during 49th cruise of R/V “Akademik Mstislav Keldysh” (September–October, 2003). The production of the symbiotic algae of acantharians and colonial radiolarians as well as their contribution to the total primary production were evaluated. The proportion of all radiolarian groups in the total zooplankton biomass was shown to range from 1.4 to 11.5%. The contribution of zooxanthellae to the total primary production was not great in the studied region and equaled 0.1–1.2 and 0.3–0.7% for colonial radiolarians and acantharians, respectively.__________Translated from Izvestiya Akademii Nauk, Seriya Biologicheskaya, No. 3, 2005, pp. 339–348.Original Russian Text Copyright © 2005 by Zasko, Rusanov.     

Nonmarine aspects of the Cambrian Tonto Group of the Grand Canyon, USA, and broader implications

A re-examination of the classic time-transgressive model of the Cambrian Tonto Group of the Grand Canyon challenges some of the basic assumptions regarding strandline migration during the Sauk transgression, the applicability of sequence stratigraphy to epicratonic deposits, and the criteria by which siliciclastic deposits of the North American Cambrian system are categorized as marine. Indicators for high short-term depositional rates, coupled with the complex splay and coalescence of meter-scale parasequence architectures, detract from the shoreline migration and deepening seas model that has held sway for over 60 years. Ostensibly marine signatures, represented by sparse and fragmentary trilobite fossils and abundant bedding plane trace fossils, are closely associated with nonmarine signatures, represented by nonmarine palynoflora and clay mineral assemblages, and highly oxidized paleoweathering profiles. The vast extent of three-dimensional exposure of the Cambrian section in the Grand Canyon shows a paleogeography not of a single discrete shoreline translated laterally with rising and falling sea-level, but of a single mosaic setting of emergent shoals and rocky peaks, broad fluvial and tidal channels, and shallow pools and interchannel flats. Much detail concerning sediment dynamics and paleoenvironment is lost or overlooked when summary terms like “marginal marine” or “nearshore” are applied to such settings. It is suggested here that the Tonto Group, with its mixed marine and nonmarine attributes, and considering its historic role as a teaching model, be viewed not as an exceptional Cambrian deposit, but as an exemplar of epicratonic deposits on a pre-vegetated landscape.     

Valanginian to Aptian calcareous nannofossil stratigraphy and correlation with the upper M-sequence magnetic anomalies

Calcareous nannofossil stratigraphy has been investigated in Lower Cretaceous Italian sections at Gorgo a Cerbara, Presale and Frontale (all in the Umbrian Apennines) and at Cismon (Southern Alps). A modified sample preparation technique has allowed a thorough stratigraphic study of the well-lithified Maiolica limestone and although nannofossil preservation is generally quite poor, the major Valanginian to Aptian marker species can be detected. Nine nannofossil events can be determined and correlated to magnetic stratigraphies previously established in these sections. Nannofossil stratigraphy confirms most magnetostratigraphic correlations made between sections and allows a more precise correlation of magnetic Chrons M-0 to M-11 with the Valanginian, Hauterivian, Barremian and Aptian stages. The results obtained differ considerably from previous timescales. Nannofossil events recorded in the various sections may be time-transgressive by as much as one magnetic chron, probably due to differential preservation.     

Hong Kong’s worst “red tide”—causative factors reflected in a phytoplankton study at Port Shelter station in 1998

From March through April 1998, a massive “red tide” occurred in coastal waters of south China, including Hong Kong. The “red tide” rapidly killed various species of caged fish and affected coral fishes, killing a few of them, and caused great economic loss and ecological damage. Samples collected from a permanent station located in Port Shelter revealed a new dinoflagellate species, Karenia digitata which was suspected to be the causative species of this “red tide”. Species composition and abundance analysis revealed that an algal bloom persisted in Port Shelter during this entire period. Diatoms and dinoflagellates were the two main groups which dominated the phytoplankton and, in general, when there was an increase in the density of diatoms there was a decline in the density of dinoflagellates, and vice versa. The suspected “red tide” causative species together with other dinoflagellate species started to bloom in late February and reached their highest density on 18 March, when fish kills were first reported at Crooked Island, a semi-enclosed bay to the northeast of Hong Kong. During a 16-week period, dinoflagellate species dominated three times, and coincided with low wind speeds. Constant salinity and a continuing increase in sea surface water temperature suggested warm water intrusion into Hong Kong’s coastal waters during this “red tide” bloom period. Various nutrient elements, e.g. NH₄-N, total Kjeldahl nitrogen (TKN), and PO₄-P were high at the beginning of the bloom but experienced a sharp decrease thereafter. It is suggested that this early 1998 massive “red tide” in Hong Kong waters might have been triggered by a synchronous appearance of optimal climatic, nutritional and hydrographic conditions.     

Catastrophic mass extinction and assemblage evolution in planktic foraminifera across the Cretaceous/Paleogene (K/Pg) boundary at Bidart (SW France)

A high-resolution biostratigraphic analysis of planktic foraminifers confirms that the Bidart section at the eastern margin of the Atlantic Ocean exhibits a continuous and complete Cretaceous/Paleogene (K/Pg) transition interval. The biozones and subzones recorded in this section are less expanded than their equivalent in Tunisian sections: El Kef (Global Stratotype Section and Point: GSSP for the K/Pg boundary) and Ellès (auxiliary section), but they are sufficiently thick to allow a detailed analysis of the evolution of the planktic foraminiferal assemblages across the K/Pg transition.Throughout the uppermost 4 m Maastrichtian, the planktic foraminiferal assemblages are highly diversified, containing up to 72 species. These Maastrichtian assemblages are rich in cosmopolitan taxa (70%), dominated by small biserial morphotypes which belong mainly to the genus Heterohelix which coexist with less abundant but highly diverse tropical and subtropical species.The extinction pattern at the Bidart section suggests a sudden catastrophic mass extinction at the K/Pg boundary which affected at least 53 out of 72 species. The species becoming extinct include globotruncanids (e.g. Contusotruncana spp., Globotruncana spp., Globotruncanita spp.) and complex heterohelicids (e.g. Racemiguembelina spp., Pseudotextularia spp., Gublerina spp.). At the Bidart section, only Archaeoglobigerina cretacea disappears 2 m below the K/Pg boundary event. Specimens of 18 small and even tiny Maastrichtian species, are found at the lowermost Danian. Only a few of these species belonging to the genera of Guembelitria, Hedbergella and Heterohelix are considered to be real “Cretaceous survivor species”, whereas the specimens belonging to the rest, are most probably reworked, because they differ in their preservation.Throughout lowermost Danian, the planktic foraminiferal assemblages are dominated by “opportunistic” species of the genus Guembelitria. These opportunists are associated to small and poorly diversified pioneer globigerinids (Palaeoglobigerina spp. and Parvularugoglobigerina spp.). These assemblages became progressively more diversified across the early Danian containing species with cancellate walls (Eoglobigerina spp., Parasubbotina spp., Subbotina triloculinoides and Praemurica spp.) and new taxa of biserial heterohelicids (Woodringina spp. and Chiloguembelina spp.) suggesting a paleoenvironmental recovery.     

Forest farming of shiitake mushrooms: An integrated evaluation of management practices

Two outdoor shiitake (Lentinula edodes) cultivation experiments, established in Missouri USA in 1999 and 2000, produced mushrooms in 2000–2005. We examined shiitake production in response to substrate species, inoculum form, inoculum strain, and inoculation timing, using total mushroom weight per log as the primary response variable with log characteristics as covariates. The significantly greater mushroom weight produced by sugar maple logs compared with white or northern red oak was attributable to the higher proportion of undiscolored wood volume in the maple logs, rather than to bark thickness or log diameter. The “wide temperature range” shiitake strain produced significantly greater yield compared with the “warm” or “cold” weather strains. Both the wide-range and warm-weather strains were stimulated to fruit by significant rain events, while the cold-weather strain was responsive to temperature. Inoculation with sawdust spawn gave significantly greater yield than colonized wooden dowels or pre-packaged “thimble” plug inoculum. The second and third full years following inoculation were the most productive.     

Relationship of Foraminifera and thecamoebian distributions to sediments contaminated by pulp mill effluent: Saguenay Fiord, Quebec, Canada

Gravity cores and grab samples collected in the Saguenay Fiord between 1976 and 1988 contain the record of a 20th century benthic marine environment contaminated primarily by organic matter discharges from several local pulp and paper mills.Spiroplectammina biformis is the dominant arenaceous species. Its living percent abundance decreases between 1982 and 1988 as a consequence of the apparent recolonization of the upper reaches of the fiord by several arenaceous taxa, the most important beingTextularia earlandi. Cassidulina reniforme, the dominant living calcareous species, shows about a three fold increase in relative abundance over the six year interval. Grab sample observations also suggest a recolonization of some formerly barren benthic environments near the head of the fiord by foraminiferal species between 1982 and 1988. This recolonization may reflect the combined effect of government regulations imposed on local industrial polluters in the early 1970's and the capping of a large area of contaminated sediment by a layer of clay that was transported to the basin at the head of the fiord as the result of a catastrophic landslide in 1971.X-radiographs of core sections from a basin at the head of the fiord show sharp laminations that reflect both the absence of bioturbators and the seasonal variation of fluvial depositional processes. Organic waste deposition from pulp and paper mill outfalls first increased around 1910 and shows a first order inverse relationship to benthonic foraminiferal assemblage diversity. The presence of only allochthonous thecamoebian and reworked planktonic Foraminifera tests in many benthonic Foraminifera-barren core intervals supports the idea that common indigenous estuarine species such asSpiroplectammina biformis were excluded from these areas at certain times as a consequence of pollution “stress” rather than having been removed from the sediment record as a result of post-depositional diagenetic effects. However, future studies of estuarine pollution history based on proxy foraminiferal data from cores must give greater emphasis to distinguishing ecological stress responses from diagenetic process (i.e. test dissolution effects) since both mechanisms can be reflected in the proxy pollution “signal” in a similar way.     

Rethinking ‘style’ for historians and philosophers of science: converging lessons from sexuality, translation, and East Asian studies

Historians and philosophers of science have furnished a wide array of theoretical-historiographical terms to emphasize the discontinuities among different systems of knowledge. Some of the most famous include Thomas Kuhn’s “paradigm”, Michel Foucault’s “episteme”, and the notion of “styles of reasoning” more recently developed by Ian Hacking and Arnold Davidson. This paper takes up this theoretical-historiographical thread by assessing the values and limitations of the notion of “style” for the historical and philosophical study of science. Specifically, reflecting on various methodological and theoretical concerns prompted by sexuality, translation, and East Asian studies, this paper argues that the heretofore ways in which historians and philosophers of science have used the notion of “style” are severely restricted in terms of its mere applicability to the intellectual history of Western science. The particular example of the translation of “homosexuality” into Chinese during the May Fourth era reveals that the notion of “style” has the potential of carrying a much more dynamic conceptual weight, as when used in “styles of argumentation”. The paper also engages briefly with the historiography of scientific “national styles” and ends with some concluding remarks on the limitations of “social histories from below” and the under appreciated importance of “epistemological histories of possibilities”.     

Utilization of 5-Bromouracil by Thymineless Bacteria

Several thymineless Escherichia coli strains have been examined for their ability to replicate their deoxyribonucleic acid when bromouracil is substituted for thymine. The procedure we describe was used to identify a thymineless strain with characteristics relatively favorable to its use in bromouracil labeling experiments. In addition, mutants with an “absolute” thymine requirement could be easily distinguished from one with a “leaky” thymine requirement.     

Stratigraphy of the western Mediterranean and southern Calabrian ridges,eastern Mediterranean

The present paper illustrates the stratigraphic results of a transponder-navigated coring program carried out in 1978 on the southern Calabrian Ridge (Cobblestone Area 4) and western Mediterranean Ridge (Cobblestone Area 3).Semi-quantitative investigations of over 600 foraminiferal samples and 450 nannofossil slides from forty cores, with a total recovery of 333 m, comprise the data base of the study.Most of the sediments recovered are Late Pleistocene or Holocene in age. The high-resolution nannofossil biostratigraphic scheme recently proposed for the Quaternary, coupled with sapropel stratigraphy and with tephrachronology resulted in precise correlation of the cores.Mid-Pleistocene sediments were recovered in a single core from Area 4, and in one core from Area 3, both located on basin walls. Four cores from basin walls in Area 4 yielded Pliocene sediments. No sediments older than approximately 3 m.y. (foraminiferal Zone M Pl 4, Reticulofenestra pseudoumbilica nannofossil Zone) are exposed on the explored walls from the southern Calabrian Ridge. Early and Late Pliocene sediments were recovered from the walls of the deepest crater-like basin explored in Area 3, but only in dredges. In this latter area also two peculiar lithologies were cored, basically unfossiliferous, but thought to be pre-Pliocene in age: a mud breccia whose clasts yield a sparse assemblage of mid-Cretaceous planktonic foraminifera, and a dolomitic mudstone, which is attributed to the Late Messinian on the basis of correlation with a similar lithology cored at DSDP Site 374, and substantiated by analogy in X-ray controlled mineralogical composition.The fairly complete record of Late Pleistocene and Holocene sapropels recovered in the southern Calabrian Ridge discards the hypothesis that the southern part of the Ionian Sea did not undergo stagnant cycles during the ice ages.Another hypothesis relating the origin of Cobblestone topography to olistostromes is also considered untenable on the basis of the new data. The large number of cores, precisely located on a previously mapped, highly irregular bottom physiography, disproves that large-scale chaotic sedimentation occurred: debris flows recorded in base-of-slope cores document local slope failures.     

Phosphorus-containing purines and pyrimidines: A new class of transition state analogs

Synthetic routes to the [1,5,2]-diazaphosphorine (“4-phosphapyrimidine”), imidazo[4,5-e][1,5,2]-diazaphosphorine (“6-phosphapurine”), and imidazo[4,5-d][1,3,2]-diazaphosphorine (“2-phosphapurine”) ring systems have been developed. Appropriately functionalized derivatives of these heterocycles are desired as possible transition state analogs of the nucleoside deaminases.     

Some connections between physiognomic traits and intelligence

A sample of 84 female subjects (students) was taken and split up on the basis of the IST-ratings (“Intelligence Structure Test” by Amthauer) into two extreme groups of “more intelligent” (N = 14) and “less intelligent” (N = 11) subjects with an aim to testing Kozeny's findings. Using his photographic-statistical method, Kozeny had observed that “more intelligent” people have a more open eye, a smaller and straighter mouth, a stronger chin, and—above all in its side dimensions—a better developed forehead. These physiognomic indicators of differences in intelligence were confirmed to a large extent by the measurements taken from the portraits of the subjects.