Enhancer-dependent interaction between 5' and 3' splice sites in trans.

Splice-site selection and alternative splicing of nuclear pre-mRNAs can be controlled by splicing enhancers that act by promoting the activity of upstream splice sites. Here we show that RNA molecules containing a 3' splice site and enhancer sequence are efficiently spliced in trans to RNA molecules containing normally cis-spliced 5' splice sites or to normally trans-spliced spliced leader RNAs from lower eukaryotes. In addition, we show that this reaction is stimulated by (Ser + Arg)-rich splicing factors that are known to promote protein-protein interactions in the cis-splicing reaction. Thus, splicing enhancers facilitate the assembly of protein complexes on RNAs containing a 3' splice site, and this complex is sufficiently stable to functionally interact with 5' splice sites located on separate RNAs. This trans-splicing is mediated by interactions between (Ser + Arg)-rich splicing factors bound to the enhancer and general splicing factors bound to the 5' and 3' splice sites. These same interactions are likely to play a crucial role in alternative splicing and splice-site selection in cis.

The Adsorption of Polyatomic Molecules on Carbon Surfaces

Carbon nanotubes exhibit the structure and chemical properties that make them apt substrates for many adsorption applications. Of particular interest are carbon nanotube bundles, whose unique geometry is conducive to the formation of pseudo-one-dimensional phases of matter, and graphite, whose simple planar structure allows ordered phases to form in the absence of surface effects. Although both of these structures have been the focus of many research studies, knowledge gaps still remain. Much of the work with carbon nanotubes has used simple adsorbates1-43, and there is little kinetic data available. On the other hand, there are many studies of complex molecules adsorbing on graphite; however, there is almost no kinetic data reported for this substrate. We seek to close these knowledge gaps by performing a kinetic study of linear molecules of increasing length adsorbing on carbon nanotube bundles and on graphite. We elucidated the process of adsorption of complex admolecules on carbon nanotube bundles, while at the same time producing some of the first equilibrium results of the films formed by large adsorbates on these structures. We also extended the current knowledge of adsorption on graphite to include the kinetics of adsorption. The kinetic data that we have produced enables a more complete understanding of the process of adsorption of large admolecules on carbon nanotube bundles and graphite. We studied the adsorption of particles on carbon nanotube bundles and graphite using analytical and computational techniques. By employing these methods separately but in parallel, we were able to constantly compare and verify our results. We calculated and simulated the behavior of a given system throughout its evolution and then analyzed our results to determine which system parameters have the greatest effect on the kinetics of adsorption. Our analytical and computational results show good agreement with each other and with the experimental isotherm data provided by our collaborators. As a result of this project, we have gained a better understanding of the kinetics of adsorption. We have learned about the equilibration process of dimers on carbon nanotube bundles, identifying the “filling effect”, which increases the rate of total uptake, and explaining the cause of the transient “overshoot” in the coverage of the surface. We also measured the kinetic effect of particle-particle interactions between neighboring adsorbates on the lattice. For our simulations of monomers adsorbing on graphite, we succeeded in developing an analytical equation to predict the characteristic time as a function of chemical potential and of the adsorption and interaction energies of the system. We were able to further explore the processes of adsorption of dimers and trimers on graphite (again observing the filling effect and the overshoot). Finally, we were able to show that the kinetic behaviors of monomers, dimers, and trimers that have been reported in experimental results also arise organically from our model and simulations.

Surface and Groundwater Environmental Policy Compliance at the Adams County Regional Park and Fairgrounds

The Adams County Regional Park and Fairgrounds must comply with environmental policies related to surface water and groundwater protection. This paper assesses various methods which have proven to be effective in the reduction of nutrients and other contaminants found in surface and groundwater at comparable livestock-based venues. Data was gathered from other facilities in order to identify specific compliance alternatives and evaluate management options. Empirical research, coupled with GIS mapping technology yielded explicit water quality management recommendations for the Adams County Regional Park and Fairgrounds. The outcome of this research and mapping exercise include twelve management recommendations and two site-specific locations for structural BMPs designed to better control water pollution at the Adams County Regional Park and Fairgrounds.

CO2 adsorption on crystalline graphitic nanostructures

CO2 adsorption has been measured in different types of graphitic nanostructures (MWCNTs, acid treated MWCNTs, graphene nanoribbons and pure graphene) in order to evaluate the effect of the different defective regions/conformations in the adsorption process, i.e., sp3 hybridized carbon, curved regions, edge defects, etc. This analysis has been performed both in pure carbon and nitrogen-doped nanostructures in order to monitor the effect of surface functional groups on surface created after using different treatments (i.e., acid treatment and thermal expansion of the MWCNTs), and study their adsorption properties. Interestingly, the presence of exposed defective regions in the acid treated nanostructures (e.g., uncapped nanotubes) gives rise to an improvement in the amount of CO2 adsorbed; the adsorption process being completely reversible. For N-doped nanostructures, the adsorption capacity is further enhanced when compared to the pure carbon nanotubes after the tubes were unzipped. The larger proportion of defect sites and curved regions together with the presence of stronger adsorbent–adsorbate interactions, through the nitrogen surface groups, explains their larger adsorption capacity.

On the behavior of the Pt(1 0 0) and vicinal surfaces in alkaline media

We address in this paper a voltammetric study of the charge transfer processes characteristic of Pt(1 0 0) and vicinal surfaces in alkaline media. The electrochemical behavior of a series of stepped surfaces of the type Pt(S)[n(1 0 0) × (1 1 1)] has been characterized using cyclic voltammetry at different pHs, charge displacement measurements and FTIR experiments for adsorbed CO. The results from these techniques allow assigning the different peaks appearing in the voltammogram to hydrogen and/or OH adsorption on the different sites of these surfaces, namely, terrace and step sites. Additionally, the potential of zero total charge (pztc) of the electrodes was determined. The resulting pztc values shift to more negative values when the step density increases on the surface up to n = 5. FTIR spectroscopy experiments have been used to monitor the adsorption of CO on the different surfaces as well as the consequent CO oxidation, accompanying a positive potential sweep. The oxidation of adsorbed CO on (1 0 0) terraces is catalyzed by the presence of the (1 1 1) steps. The FTIR spectra revealed that CO is mostly bonded in bridge configuration at low potentials interconverting to on-top when the electrode potential is increased.

Mineral, chemical and isotopic compositions of altered rocks at ODP Sites 193-1188 and 193-1189

During ODP Leg 193, 4 sites were drilled in the active PACMANUS hydrothermal field on the crest of the felsic Pual Ridge to examine the vertical and lateral variations in mineralization and alteration patterns. We present new data on clay mineral assemblages, clay and whole rock chemistry and clay mineral strontium and oxygen isotopic compositions of altered rocks from a site of diffuse low-temperature venting (Snowcap, Site 1188) and a site of high-temperature venting (Roman Ruins, Site 1189) in order to investigate the water-rock reactions and associated elemental exchanges. The volcanic succession at Snowcap has been hydrothermally altered, producing five alteration zones: (1) chlorite+/-illite-cristobalite-plagioclase alteration apparently overprinted locally by pyrophyllite bleaching at temperatures of 260-310°C; (2) chlorite+/-mixed-layer clay alteration at temperatures of 230°C; (3) chlorite and illite alteration; (4) illite and chlorite+/-illite mixed-layer alteration at temperatures of 250-260°C; and (5) illite+/-chlorite alteration at 290-300°C. Felsic rocks recovered from two holes (1189A and 1189B) at Roman Ruins, although very close together, show differing alteration features. Hole 1189A is characterized by a uniform chlorite-illite alteration formed at ~250°C, overprinted by quartz veining at 350°C. In contrast, four alteration zones occur in Hole 1189B: (1) illite+/-chlorite alteration formed at ~300°C; (2) chlorite+/-illite alteration at 235°C; (3) chlorite+/-illite and mixed layer clay alteration; and (4) chlorite+/-illite alteration at 220°C. Mass balance calculations indicate that the chloritization, illitization and bleaching (silica-pyrophyllite assemblages) alteration stages are accompanied by different chemical changes relative to a calculated pristine precursor lava. The element Cr appears to have a general enrichment in the altered samples from PACMANUS. The clay concentrate data show that Cr and Cu are predominantly present in the pyrophyllites. Illite shows a significant enrichment for Cs and Cu relative to the bulk altered samples. Considerations of mineral stability allow us to place some constraints on fluid chemistry. Hydrothermal fluid pH for the chloritization and illitization was neutral to slightly acidic and relatively acidic for the pyrophyllite alteration. In general the fluids, especially from Roman Ruins and at intermediate depths below Snowcap, show only a small proportion of seawater mixing (<10%). Fluids in shallow and deep parts of the Snowcap holes, in contrast, show stronger seawater influence.

(Appendix) Relative abundance of planktonic foraminifera in ODP Site 138-846 late Quaternary sediments

High-resolution records of d18O and relative abundances of planktonic foraminifers were generated for ODP Leg 138 Site 846 for the past 800 k.y., with an average sampling interval of 3.6 k.y. The time scale was constructed by correlating the benthic d18O record to the SPECMAP and ODP Site 677 d18O time scales using the mapping function technique of Martinson et al. (1981). Our observations show that variations in the foraminiferal assemblages, although influenced by dissolution, are interpretable in terms of changing characteristics of upper ocean waters. Carbonate dissolution as indicated by fragmentation of planktonic foraminifers shows concentrated variance that is coherent with d18O at the 100 and 41 k.y. orbital periods. At these periods, maximum dissolution occurs during interglacial extremes. This finding differs from previous studies that have indicated that in this region percent carbonate minimum lags global ice volume minimum. N. dutertrei and dextral N. pachyderma dominate the assemblages, but do not show consistent relationships relative to glacial-interglacial cycles. However, less abundant species G. ruber, G. menardii, G. glutinata and G. sacculifer show positive and G. bulloides negative correlation with the d18O record. Q-mode factor analysis of the Site 846 assemblages and comparison with modern assemblages suggest the following. Prior to and during interglacials, the area was considerably warmer and more subtropical than at present; during glacials, the area was colder than at present with greater upwelling and advection off the eastern boundary, and possibly a stronger Peru Current; the equatorial ôcool tongueö was also possibly stronger.

Late Miocene to Quaternary planktonic foraminifera of ODP SIte 114-704

The planktonic foraminiferal zonation of Jenkins and Srinivasan (1986), which was defined for the southwestern sector of the temperate South Pacific Ocean, was successfully extended to the temperate sequences at Site 704. The zonation is based on first and last appearances of globorotalids, principally Globoconella species, which are indigenous to temperate surface-water masses. Most of the first and last appearances at ODP Site 704 are diachronous with those in the warmer temperate to subtropical South Atlantic, North Atlantic, and South Pacific oceans. The upper Miocene, upper Pliocene, and Quaternary sequences are punctuated by frequent incursions of subantarctic and polar assemblages of planktonic foraminifers. I assume that the appearance of an assemblage dominated by sinistral Neogloboquadrina pachyderma means that the Polar Front has migrated northward, but I do not know its position north or south of the site based on this preliminary work. The upper Miocene sequence contains five incursions between 6.5 and 5 Ma and the upper Pliocene and Quaternary sequence contains 16 events since 2.47 Ma. These are minimum estimates because the number of observed events will probably increase with higher sample density and use of quantitative methods to reveal more subtle events.

Organic carbon, calcium carbonate and carbon/nitrogen ratio at DSDP Leg 93 sites

A large number of samples of nonlithified and lithified sediments from Leg 93 sites were analyzed for their contents of organic carbon and calcium carbonate. An average of two samples was selected from every core for carbonate determination; organic carbon was measured in most of these samples. Nearly all of these analyses were performed on board Glomar Challenger for samples from Sites 603 and 604. Site 605 samples, plus some of the deeper samples from Hole 603B, were analyzed at the University of Michigan. The procedures used in both cases were virtually the same, and their results compared well. Organic carbon analyses were done using a Hewlett- Packard 185-B CHN Analyzer. Portions of samples selected for calcium carbonate determinations were treated with dilute HC1 to remove carbonate, washed with deionized water, and dried at 110°C. A Cahn Electrobalance was used to weight 20-mg samples of sediment for CHN analysis. Samples were combusted at 1050°C in the presence of an oxidant, and the volumes of the evolved gases determined as measures of the C, H, and N contents of sediment organic matter. Areas of gas peaks were determined and compared to those of rock standards of known carbon and nitrogen contents. These values were used to standardize instrument response so that C/N atomic ratios could be reported. Organic carbon concentrations were calculated on the basis of sediment dry weight. Hydrogen elemental analysis with the procedure used is untrustworthy because of the variable amounts of clay minerals and their hydrates, hence hydrogen values are not reported for samples analyzed by this method.

(Table 2) Oxygen and carbon isotope composition of planktonic foraminiferal species from DSDP Holes 93-603B and 93-604, and one benthic species from Hole 93-604

Holes 603C and 604 of DSDP Leg 93 were drilled on the western Atlantic continental rise at water depths of 4633 m and 2364 m, respectively. In Hole 603C, a nearly continuous, undisturbed, and complete section of Pliocene and lower Pleistocene sediments was recovered by hydraulic piston coring; in Hole 604, a section of uppermost Miocene to Pleistocene sediments was incompletely recovered by rotary coring. In order to reconstruct the Pliocene and Pleistocene history of isotopic variations, 139 oxygen and carbon isotope values were determined for planktonic and monospecific benthic foraminifer samples from these holes. Large parts of the Pleistocene history could not, however, be documented because sample intervals were large and sediments at Site 604 were redeposited. Time correlation is based on magnetostratigraphic (Hole 603C) and micropaleontologic (Hole 603C, Site 604) interpretation. Stable isotope analyses were carried out on the planktonic foraminiferal species Globigerinoides ruber, G. obliquus, and Globorotalia inflata from Hole 603C (48 analyses) and from Site 604 (48 analyses); at Site 604, the benthic foraminifer Uvigerina peregrina (43 analyses) was also studied through the section. Age calibration for Hole 603C is based on the magnetostratigraphy of Canninga et al. (1987; doi:10.2973/dsdp.proc.93.130.1987), which uses the time scale of Lowrie and Alvarez (1981).

Oligocene to Miocene stable isotope record and planktonic foraminifer biostratigraphy of the Sierra Leone Rise

We have integrated Oligocene to lower upper Miocene planktonic foraminifer biostratigraphy with benthic foraminifer (Cibicidoides spp.) stable isotope records for two sites drilled on opposite sides of the Sierra Leone Rise in the eastern equatorial Atlantic Ocean. Deep Sea Drilling Project Site 366 (2853 m present water depth; 2200-2800 m paleodepth) recovered an Oligocene to upper Miocene record with a minor unconformity in the "middle" Oligocene and a condensed middle Miocene section. Ocean Drilling Program Site 667 (3529 m present depth; 3000-3500 m paleodepth) recovered an apparently continuous "middle" Oligocene to lower middle Miocene record and a similar condensed middle Miocene section. The Oligocene to lower Miocene sections were deposited at similar sedimentation rates (~11-16 m/m.y.). Stable isotope stratigraphy proved to be useful in establishing intra- and interbasinal correlations. In addition to the well-known earliest Oligocene and middle Miocene S180 increases, a distinct d18O increase occurred near the Oligocene/Miocene boundary. Carbon isotope variations provide similar potential for improving correlations; for example, a d13C increase occurred near the Oligocene/Miocene boundary in concert with increased d18O values. There was little d13C difference between the western Atlantic and eastern Atlantic basins during the late Oligocene and most of the middle Miocene; in contrast, eastern basin d13C values were slightly lower than those in the western basins during the earliest Oligocene (about 35-33 Ma) and early Miocene (about 22-18 Ma).

Calcium carbonate, organic carbon, sediment description and hydrogen and oxygen index at DSDP Sites 93-603, 93-605, 93-604 and 95-603

The organic matter contents of sediments and rocks sampled during DSDP Leg 93 have been characterized by CHN and Rock-Eval analyses. Most samples from Sites 604 and 605 on the New Jersey continental slope and from Site 603 on the Hatteras outer continental rise contained less than 0.5% organic carbon. Some Neogene samples from the slope contained 1 to 2% organic carbon, and Cretaceous samples from the outer rise were as rich as 13.6% organic carbon by weight. Thin layers of black claystones of Santonian, Cenomanian, and Albian age were found interbedded in organiccarbon- lean, bioturbated, turbiditic claystones. Similar layers of turbiditic black marlstones were interspersed among Neocomian limestones and sandstones. Although the organic matter in many of the samples appeared to be detrital continental material, according to Rock-Eval and C/N values, Cenomanian black shales, in particular, contained substantial proportions of marine-derived organic matter.

Calcareous nannofossil abundance and datums of ODP Leg 189 sites

Quaternary sediments were recovered at all five sites drilled during Ocean Drilling Program (ODP) Leg 189 in the Tasmanian Gateway. Two of these sites lie north of the present-day Subtropical Front (STF), and three sites lie south of the STF. Quaternary sediments recovered at Sites 1168, 1170, 1171, and 1172 were studied in detail to determine the calcareous nannofossil biostratigraphy and construct an age model for these sediments. The Pliocene/Pleistocene boundary was identified by the last occurrence (LO) of Discoaster brouweri at Site 1172 and approximated by the LO of Calcidiscus macintyrei at the other sites because of a lack of discoasterids. A hiatus encompassing the entire Helicosphaera sellii Zone was tentatively identified at Sites 1168 and 1172 by the coincident LOs of C. macintyrei and H. sellii. Similar hiatuses have been noted at ODP Site 1127 on the Great Australian Bight, Deep Sea Drilling Project Site 282 off the Tasman subcontinent, and ODP Site 1165 in Prydz Bay, Antarctica.

Sorption properties of sediments and energy-related pollutants /

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Adsorption of biochemically resistant materials from solution. 2. /

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