Plutonismn in three orogenic pulses, Eastern Blue Ridge Province, southern Appalachians

The Eastern Blue Ridge Province of the southern Appalachians contains, in part, remnants of an Ordovician accretionary wedge complex formed during subduction of an oceanic tract before mid-Ordovician accretion with Laurentia. The Eastern Blue Ridge Province consists of metapelite and amphibolite intruded by low-K plutons, high-temperature (T >750 °C) Ordovician eclogite, and other high-pressure metamafic and meta-ultramafic rocks. Felsic plutons in the Eastern Blue Ridge Province are important time markers for regional-scale tectonics, deformation, and metamorphism. Plutons were thought to be related to either Taconian (Ordovician) or Acadian (Devonian-Silurian) tectonothermal events. We dated five plutonic or metaplutonic rocks to constrain pluton crystallization ages better and thus the timing of tectonism. The Persimmon Creek gneiss yielded a protolith crystallization age of 455.7 ± 2.1 Ma, Chalk Mountain 377.7 ± 2.5 Ma, Mt. Airy 334 ± 3Ma, Stone Mountain 335.6 ± 1.0 Ma, and Rabun 335.1 ± 2.8 Ma. The latter four plutons were thought to be part of the Acadian Spruce Pine Suite, but instead our new ages indicate that Alleghanian (Carboniferous-Permian) plutonism is widespread and voluminous in the Eastern Blue Ridge Province. The Chattahoochee fault, which was considered an Acadian structure, cuts the Rabun pluton and thus must have been active during the Alleghanian orogeny. The new ages indicate that Persimmon Creek crystallized less than 3 m.y. after zircon crystallization in Eastern Blue Ridge eclogite and is nearly synchronous with nearby high-grade metamorphism and migmatization. The three phases of plutonism in the Eastern Blue Ridge Province correspond with established metamorphic ages for each of the three major orogenic pulses along the western flank of the southern Appalachians. © 2006 Geological Society of America.

Automatic segmentation of latent fingerprints

Latent fingerprints are routinely found at crime scenes due to the inadvertent contact of the criminals' finger tips with various objects. As such, they have been used as crucial evidence for identifying and convicting criminals by law enforcement agencies. However, compared to plain and rolled prints, latent fingerprints usually have poor quality of ridge impressions with small fingerprint area, and contain large overlap between the foreground area (friction ridge pattern) and structured or random noise in the background. Accordingly, latent fingerprint segmentation is a difficult problem. In this paper, we propose a latent fingerprint segmentation algorithm whose goal is to separate the fingerprint region (region of interest) from background. Our algorithm utilizes both ridge orientation and frequency features. The orientation tensor is used to obtain the symmetric patterns of fingerprint ridge orientation, and local Fourier analysis method is used to estimate the local ridge frequency of the latent fingerprint. Candidate fingerprint (foreground) regions are obtained for each feature type; an intersection of regions from orientation and frequency features localizes the true latent fingerprint regions. To verify the viability of the proposed segmentation algorithm, we evaluated the segmentation results in two aspects: a comparison with the ground truth foreground and matching performance based on segmented region. © 2012 IEEE.

Influence of buccal bony crest width on marginal dimensions of peri-implant hard and soft tissues after implant installation. An experimental study in dogs

Aim: To evaluate the influence of the width of the buccal bony wall on hard and soft tissue dimensions following implant installation. Material and methods: Mandibular premolars and first molars of six Labrador dogs were extracted bilaterally. After 3 months of healing, two recipient sites, one on each side of the mandible, were prepared in such a way as to obtain a buccal bony ridge width of about 2 mm in the right (control) and 1 mm in the left sides (test), respectively. Implants were installed with the coronal margin flush with the buccal alveolar bony crest. Abutments were placed and the flaps were sutured to allow a non-submerged healing. After 3 months, the animals were euthanized and ground sections obtained. Results: All implants were completely osseointegrated. In respect to the coronal rough margin of the implant, the most coronal bone-to-implant contact was apically located 1.04 ± 0.91 and 0.94 ± 0.87 mm at the test and control sites, respectively, whereas the top of the bony crest was located 0.30 ± 0.40 mm at the test and 0.57 ± 0.49 mm at the control sites. No statistically significant differences were found. A larger horizontal bone resorption, however, evaluated 1 mm apically to the rough margin, was found at the control (1.1 ± 0.7 mm) compared to the test (0.3 ± 0.3 mm) sites, the difference being statistically significant. A thin peri-implant mucosa (2.4-2.6 mm) was found at implant installation while, after 3 months of healing, a biological width of 3.90-4.40 mm was observed with no statistically significant differences between control and test sites. Conclusions: A width of the buccal bony wall of 1or 2 mm at implant sites yielded similar results after 3 months of healing in relation of hard tissue and soft tissues dimensions after implant installation. © 2012 John Wiley & Sons A/S.

Influence of presence or absence of keratinized mucosa on the alveolar bony crest level as it relates to different buccal marginal bone thicknesses. an experimental study in dogs

Objective: To investigate the influence of the presence or absence of keratinized mucosa on the alveolar bony crest level as it relates to different buccal marginal bone thicknesses. Material and methods: In six beagle dogs, the mandibular premolars and first molars were extracted bilaterally. In the right side of the mandible (test), flaps were elevated, and the buccal as well as part of the lingual masticatory mucosa was removed. The flap was released coronally to allow a primary wound closure. In the left side, the wounds were left unsutured with the keratinized mucosa remaining (control). After 3 months of healing, a complete absence of keratinized mucosa was found at the test sites. Two recipient sites were prepared at each side of the mandible, one in the premolar and one in the molar region. A buccal bony ridge width of approximately 1 and 2 mm was obtained at the premolar and molar region, respectively. Implants were installed with the shoulder flush with the buccal alveolar bony crest, and abutments were connected to allow a nonsubmerged healing. At least 2 mm of keratinized mucosa was surrounding the control sites, while at the test sites, the implants were bordered by alveolar mucosa. After 3 months, the animals were euthanized and ground sections obtained. Results: A higher vertical bony crest resorption was observed at the test compared with the control sites both at the premolar and molar regions, the differences being statistically significant. The top of the peri-implant mucosa was located more coronally at the control compared with the test sites. The horizontal resorption measured 1 mm below the implant shoulder was similar at the test and control sites. Only limited differences were found between premolar and molar sites, with the exclusion of the horizontal resorption that was higher at the test compared with the control sites. Conclusions: A higher alveolar buccal bony crest resorption and a more apical soft tissue marginal position should be expected, when implants are surrounded with thin alveolar mucosa at the time of installation, independently of the thickness of the buccal bony crest. © 2013 John Wiley & Sons A/S.

Agriculture Builders of Nebraska Annual Meeting

Anthony McAuliffe was acting commander of the 101st Airborne Division during the Battle of the Bulge in World War II. December 22, 1944, he was in charge of the-defense of Bastogne when advancing German forces called upon his garrison to surrender.

Talking through walls: a history of the murals in Northern Ireland

This dissertation examines how some fundamental events of the history of Ireland emerge through the art of the mural. It is divided into three chapters. The first chapter opens with a brief presentation of the mural as a form of art with a semiotic and sociological function, with a particular focus on the socio-political importance it has had and still has today in Ireland, where murals are a significant means of expressing ideals, protest and commemoration. A part of this chapter also provides data about the number of murals and their location, with a particular focus on the two cities of Belfast and Derry. This first chapter ends with the presentation of an initiative put forth by the Arts Council of Northern Ireland, called "Building Peace through the Arts: Re-Imaging Communities", and questions its implementation on the Irish soil. The second chapter provides a history of the murals in Northern Ireland, from the Unionist's early depictions of King Billy in occasion of the 12 July annual celebrations to the Republican response. This will be supported by an explanation of the two events that triggered the start of the mural painting for both factions: the Battle of the Boyne for the Loyalists and the 1981 hunger strike for the Republicans. In the third and last chapter of this dissertation, a key of the main themes, symbols, acronyms and dominant colours which can be found in Loyalist and Republican murals is provided. Furthermore, one mural for each faction is looked at more closely, with an analysis of the symbols which are present in it.

Fingering instability down the outside of a vertical cylinder

We present an experimental and numerical study examining the dynamics of a gravity-driven contact line of a thin viscous film traveling down the outside of a vertical cylinder of radius R. Experiments on cylinders with radii ranging between 0.159 and 3.81 cm show that the contact line is unstable to a fingering pattern for two fluids with differing viscosities, surface tensions, and wetting properties. The dynamics of the contact line is studied and results are compared to previous studies of inclined plane experiments in order to understand the influence substrate curvature plays on the fingering pattern. A lubrication model is derived for the film height in the limit that ε = H/R≪1, where H is the upstream film thickness, and in terms of a Bond number ρgR3/(γH), and the linear stability of the contact line is analyzed using traveling wave solutions. Curvature controls the capillary ridge height of the traveling wave and the range of unstable wavelength when ε = O(10-1), whereas the shape and stability of the contact line converge to the behavior one observes on a vertical plane when ε ≤ O(10-2). The most unstable wave mode, cutoff wave mode for neutral stability, and maximum growth rate scale as 0.45 where = ρgR2/γ ≥ 1.3, and the contact line is unstable to fingering when ≥ 0.56. Using the experimental data to extrapolate outside the range of validity of the thin film model, we estimate the contact line is stable when <0.56. Agreement is excellent between the model and the experimental data for the wave number (i.e., number of fingers) and wavelength of the fingering pattern that forms along the contact line.

Perforation of the sinus membrane during sinus floor elevation: a retrospective study of frequency and possible risk factors.

PURPOSE To analyze the frequency of perforation of the sinus membrane during maxillary sinus floor elevation (SFE) and to assess possible risk factors. MATERIALS AND METHODS Seventy-seven cases of SFE performed with a lateral window approach were evaluated retrospectively. Clinical and radiographic variables potentially influencing the risk of sinus membrane perforation were evaluated and divided into patient-related factors (age, sex, smoking habit); surgery-related factors (type of surgical approach, side, units, sites, and technique of osteotomy); and maxillary sinus-related factors (presence and height of septum, height of residual ridge, thickness of lateral sinus wall, width of antrum, and thickness and status of sinus membrane). RESULTS The following factors presented with at least a 10% difference in rates of perforations: smokers (46.2%) versus nonsmokers (23.4%), simultaneous (32%) versus staged (18.5%) approach, mixed premolar-molar sites (41.2%) versus premolar-only sites (16.7%) versus molar-only sites (26.2%), presence of septa (42.9%) versus no septa (23.8%), and minimum height of residual ridge ≤4 mm (34.2%) versus > 4 mm (20.5%). These same parameters, except minimum height of residual ridge, also showed an odds ratio above 2. However, none of the comparisons reached statistical significance. CONCLUSION The present study failed to demonstrate any factor that statistically significantly increased the risk of sinus membrane perforation during SFE using the lateral window approach.

Isolation and characterization of cDNAs encoding novel homeoproteins from chondrocytes

Bone morphogenesis is a complex biological process. The multistep process of chondrogenesis is the most important aspect of endochondral bone formation. To study the mechanisms which control this multistep pathway of chondrogenesis during embryonic development, I started by isolating cDNAs encoding novel transcriptional factors from chondrocytes. Several such cDNAs encoding putative homeoproteins were identified from a rat chondrosarcoma cDNA preparation. I have been concentrating on characterizing two of these cDNAs. The deduced amino acid sequence of the first homeoprotein, Cart-1, contains a prd-type homeodomain. Northern hybridization and RNase protection analysis revealed that Cart-1 RNAs were present at high levels in a well differentiated rat chondrosarcoma tumor and in a cell line derived from this tumor. Cart-1 transcripts were also detected in primary chondrocytes, but not in numerous other cell types except very low levels in testis. In situ hybridization of rat embryos at different stages of development revealed relatively high levels of Cart-1 RNAs in prechondrocytic mesenchymal cells and in early chondrocytes of cartilage primordia. It is speculated that Cart-1 might play an important role in chondrogenesis. The second putative homeoprotein, rDlx, contains a Distal-less-like homeodomain. rDlx RNAs were also present at high levels in the rat chondrosarcoma tumor and in the cell line derived from this tumor. In situ hybridization of rat embryos revealed high levels of rDlx transcripts in the developing cartilages and perichondria of mature cartilages. rDlx transcripts were also detected in a number of nonchondrogenic tissues such as forebrain, otic vesicles, olfactory epithelia, apical ectodermal ridge (AER) of limb buds, the presumptive Auerbach ganglia of gastrointestinal tract. The unique expression pattern of rDlx suggests that it might play important roles in chondrogenesis and other aspects of embryogenesis. ^

Relative abundance and ranges of selected diatoms from Pliocene-Pleistocene sections of ODP Leg 177, Atlantic sector of the Southern Ocean

During Ocean Drilling Program (ODP) Leg 177, seven sites were drilled aligned on a transect across the Antarctic Circumpolar Current in the Atlantic sector of the Southern Ocean. The primary scientific objective of Leg 177 was the study of the Cenozoic paleoceanographic and paleoclimatic history of the southern high latitudes and its relationship with the Antarctic cryosphere development. Of special emphasis was the recovery of Pliocene-Pleistocene sections, allowing paleoceanographic studies at millennial or higher time resolution, and the establishment of refined biostratigraphic zonations tied to the geomagnetic polarity record and stable isotope records. At most sites, multiple holes were drilled to ensure complete recovery of the section. A description of the recovered sections and the construction of a multihole splice for the establishment of a continuous composite is presented in the Leg 177 Initial Reports volume for each of the sites (Gersonde, Hodell, Blum, et al., 1999). Here we present the relative abundance pattern and the stratigraphic ranges of diatom taxa encountered from shore-based light microscope studies completed on the Pliocene-Pleistocene sequences from six of the drilled sites (Sites 1089-1094). No shore-based diatom studies have been conducted on the Pliocene-Pleistocene sediments obtained at Site 1088, located on the northern crest of the Agulhas Ridge, because of the scattered occurrence and poor preservation of diatoms in these sections (Shipboard Scientific Party, 1999b). The data included in our report present the baseline of a diatom biostratigraphic study of Zielinski and Gersonde (2002), which (1) includes a refinement of the southern high-latitude Pliocene-Pleistocene diatom zonation, in particular for the middle and late Pleistocene, and (2) presents a biostratigraphic framework for the establishment of age models of the recovered sediment sections. Zielinski and Gersonde (2002) correlated the diatom ranges with the geomagnetic polarity record established shipboard (Sites 1090 and 1092) (Shipboard Scientific Party, 1999c, 1999d) and on shore (Sites 1089, 1091, 1093, and 1094) by Channell and Stoner (2002). The Pliocene-Pleistocene diatom zonation proposed by Zielinski and Gersonde (2002) relies on a diatom zonation from Gersonde and Bárcena (1998) for the northern belt of the Southern Ocean. Because of latitudinal differentiation of sea-surface temperature, nutrients, and salinity between Antarctic and Subantarctic/subtropical water masses, the Pliocene-Pleistocene stratigraphic marker diatoms are not uniformly distributed in the Southern Ocean (Fenner, 1991; Gersonde and Bárcena, 1998). As a consequence, Zielinski and Gersonde (2002) propose two diatom zonations for application in the Antarctic Zone south of the Polar Front (Southern Zonation, Sites 1094 and 1093) and the area encompassing the Polar Front Zone (PFZ) and the Subantarctic Zone (Northern Zonation, Sites 1089-1092). This accounts especially for the Pleistocene zonation where Hemidiscus karstenii, whose first abundant occurrence datum and last occurrence datum defines the subzonation of the northern Thalassiosira lentiginosa Zone, occurs only sporadically in the cold-water realm south of the PFZ and thus is not applicable in sections from this area. However, newly established marker species assigned to the genus Rouxia (Rouxia leventerae and Rouxia constricta) are more related to cold-water environments and allow a refinement of the Pleistocene stratigraphic zonation for the southern cold areas. A study relying on quantitative counts of both Rouxia species confirms the utility of these stratigraphic markers for the identification of sequences attributed to marine isotope Stages 6 and 8 in the southern Southern Ocean (Zielinski et al., 2002).

Element concentrations of plagioclase and clinopyroxene in poikilitic olivine gabbros from ODP Hole 153-923A (Table 4)

Ocean Drilling Program Hole 923A, located on the western flank of the Mid-Atlantic Ridge south of the Kane Fracture Zone, recovered primitive gabbros that have mineral trace element compositions inconsistent with growth from a single parental melt. Plagioclase crystals commonly show embayed anorthitic cores overgrown by more albitic rims. Ion probe analyses of plagioclase cores and rims show consistent differences in trace element ratios, indicating variation in the trace element characteristics of their respective parental melts. This requires the existence of at least two distinct melt compositions within the crust during the generation of these gabbros. Melt compositions calculated to be parental to plagioclase cores are depleted in light rare earth elements, but enriched in yttrium, compared to basalts from this region of the Mid-Atlantic Ridge, which are normal mid-ocean ridge basalt (N-MORB). Clinopyroxene trace element compositions are similar to those predicted to be in equilibrium with N-MORB. However, primitive clinopyroxene crystals are much more magnesian than those produced in one-atmosphere experiments on N-MORB, suggesting that the major element composition of the melt was unlike N-MORB. These data require that the diverse array of melt compositions generated within the mantle beneath mid-ocean ridges are not always fully homogenised during melt extraction from the mantle and that the final stage of mixing can occur efficiently within crustal magma chambers. This has implications for the process of melt extraction from the mantle and the liquid line of descent of MORB

Rb, Sr, Sm and Nd concentrations and isotopic composition of basalts from DSDP Leg 74 (Table 1)

Basement intersected in DSDP holes 525A, 528 and 527 on the Walvis Ridge consists of submarine basalt flows and pillows with minor intercalated sediments. These holes are situated on the crest and mid and lower northwest flank of a NNW-SSE-trending ridge block which would have closely paralleled the paleo mid-ocean ridge (Rabinowitz and LaBrecque, 1979 doi:10.1029/JB084iB11p05973, Moore et al. (1983 doi:10.1130/0016-7606(1983)94<907:TWRTDS>2.0.CO;2). The basalts were erupted approximately 70 m.y. ago, an age equivalent to that of immediately adjacent oceanic crust in the Angola Basin and coraistent with formation at the paleo mid-ocean ridge (Moore et al., 1983). The basalt types vary from aphyric quartz tholeiites on the ridge crest to highly plagioclase phyric olivine tholeiites on the ridge flank. These show systematic differences in incompatible trace element and isotopic composition. Many element and isotope ratio pairs form systematic trends with the ridge crest basalts at one end and the highly phyric ridge flank basalts at the other. The low 143Nd/144Nd (0.51238), 206Pb/204Pb (17.54), 207Pb/204Pb (15.47), 208Pb/204Pb (38.14) and high 87Sr/86Sr (0.70512) ratios of the ridge crest basalts suggest derivation from an old Nd/Sm-, Rb/Sr- and Pb/U-enriched mantle source. This isotopic signature is similar to that of alkaline basalts on Tristan da Cunha but offset to significantly lower Nd and Pb isotopic ratios. The isotopic ratio trends may be extrapolated beyond the ridge flank basalts with higher 143Nd/144Nd (0.51270), 206Pb/204Pb (18.32), 207Pb/204Pb (15.52), 208Pb/204Pb (38.77) and lower 87Sr/86Sr (0.70417) ratios in the direction of increasingly Nd/Sm-, Rb/Sr- and Pb/U-depleted source compositions. These isotopic correlations are equally consistent with mixing of depleted and enriched end member melts or partial melting of an inhomogeneous, variably enriched mantle source. However, observed Zr-Ba-Nb-Y interelement relationships are inconsistent with any simple two-component model of magma mixing, as might result from the rise of a lower mantle plume through the upper mantle. Incompatible element and Pb isotopic systematics also preclude extensive involvement of depleted (N-type) MORB material or its mantle sources. In our preferred petrogenetic model the Walvis Ridge basalts were derived by partial melting of mantle similar to an enriched (E-type) MORB source which had become heterogeneous on a small scale due to the introduction of small-volume melts and metasomatic fluids.

Average contents of chemical elements in different types of hydrothermal manifestations within 16°38'N hydrothermal field, MAR

An additional ore field in the central part of the MARhas been discovered. Together with previously discovered Logachev (14°45'N) and Ashadze (12°58'N) ore fields, the new ore field constitutes a cluster with preliminarily estimated total ore reserve of >10 Mt, which is comparable with large continental massive sulfide deposits.

(Table 2) Chemical composition of quenched glasses from the Mohns and Knipovich Ridges

The aim of this project was a petrogeochemical study of igneous rocks in the areas of the Mohns and Knipovich Ridges, both being the northern extensions of the Mid-Atlantic Ridge (MAR), using data available for quenching glass samples collected during Cruises 36 and 38 of R/V Akademic Mstislav Keldysh and during Cruise 15 of R/V Professor Logachev. Results of igneous rock studying from the Mohns and Knipovich Ridges at the background of evolution of the total North Atlantic Province, which had been identified earlier from tectonic and geophysical data, showed that igneous rocks of the Knipovich Ridge can be ranked as shallow tholeiites, primary melts of which were relatively rich in Na and Si and poor in Fe. This type of magma is characteristic of colder regions of the oceanic lithosphere. Its occurrence in the Knipovich Ridge and its potential propagation up to the Gakkel Ridge suggest that igneous rocks of this region originated under conditions of passive spreading in contrast to the MAR region in vicinity of Iceland and Azores, where substantial contribution of hotter material of a rising plume contributed to formation of the oceanic crust. The North Atlantic Ocean is the youngest province in terms of ocean-floor opening. Geologically and geophysically it is one of well studied regions of the World Ocean. Nevertheless some basic key items of its origin still remain to be clarified. In 1975 Scatler et al. proved specifics of this region manifested in growth of the gravity field, and also in relative height of the ocean floor in the region of 33-70°N, which was associated by them with rise of the hotter mantle, as compared with common regions of the Mid-Atlantic Ridge. Later this view was confirmed by character of magmatism, which differed in depth of generation and by melting degree of the resulting primary magma. Uniqueness of the North Atlantic region was also proved by the fact that this region was marked by extensive geochemical anomalies associated with Azores, Iceland, and Jan Mayen. All of these data allow to consider the northern part of the MAR (north of 33°N) as an united global geotectonic province. The Mohns and Knipovich Ridges located north of Iceland locate at the northern end of this province. This is the least known region. Therefore, new data for ridge areas of 73-77°N are needed for more complete geologic history of the Arctic Basin. The aim of this study was to carry out a complex comparison of magmatism at the Mohns and Knipovich Ridges with magmatism at large segments of the MAR northern province and to reconstruct mechanisms of primary magma formation, as well as conditions of their fractionation. This paper was based on results of studying quenched glasses, which reflect evolution of melt in the course of its formation.