Paleoenvironmental reconstruction of the Oligocene-Miocene deposits of the Tethyan Seaway, Qom Formation, Central Iran

Science.gov (United States)

Dabaghi Sadr, Fatemeh; Schmiedl, Gerhard

2017-04-01

The Cenozoic climate transition from greenhouse to icehouse conditions was associated with major paleogeographic changes in the Tethyan realm. The closure of the Tethyan Seaway and its Iranian gateways during the terminal Paleogene and early Neogene, between approximately 28 and 18 million years, influenced the latitudinal exchange of water masses and energy and is documented in sediment successions of the Qom formation in central Iran. Little is known on the spatial expression and the exact depositional histories of the Qom Formation on orbital time-scales, including a lack of quantitative sea-level reconstructions and studies on the impact of climatic and tectonic changes on marine ecosystems and sedimentation processes. The PhD project focuses on the investigation of lithostratigraphy, biostratigraphy, paleoecology and paleoenvironmental evolution of the Iranian gateways based on late Oligocene to early Miocene foraminiferal faunas and carbonate facies from selected sediment sections of the Qom Basin. The Qom Formation was deposited in the Central Iranian back-arc basin during the Oligocene-Miocene. In this study foraminiferal faunas and carbonate microfacies were studied based on total 191 samples of two section of Qom Formation. One of them is Molkabad section, which is located northwest of Molkabad mountains, southeast of Garmsar. The section mainly consists of limestones, calcareous marls, marls, and gypsum-bearing marls with a total thickness of 760 meters. The Qom Formation at Molkabad section overlies Eocene rocks with an unconformity and consists of the following lithostratigraphic units (from the lower to upper part): Lithothamnium Limestone, Lower Marl Limestone, Bryozoa Limestone, and Upper Marl Group. The Molkabad fault separates the Qom Formation from the overlying Upper Red Formation. The other section is located at Navab anticline in Qom Formation .The section mainly consist of limestone, marl, and gypsum with a total thickness of 318 meters Navab

The Cooperative Education as central axis for the integral Formation in the cooperative sector

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Iriadna Marín de León

2013-06-01

Full Text Available The cooperative constitutes one of the most important sectors in the economy in any economic formation - social, its fundamental cell is the man's integral development who should be capable for, from a reflexive and creative position, to assume the challenges that it implies an efficient and effective administration in function of the cooperative company. It is the educational dimension in cooperative values the key for the future, conceived in a systematic way and assuming an appropriate methodological conception. In this perspective, leaving of the theoretical foundation of the administration of the human resources in general, he intends to be carried out an integral analysis of the formation processes and education for the cooperative with the purpose of valuing the central aspects of this thematic one, leaving of the fact that the education constitutes the medullary element that leads to a true cooperative formation.

AN APPROACH TO PROVENANCE, TECTONIC AND REDOX CONDITIONS OF JURASSIC-CRETACEOUS AKKUYU FORMATION, CENTRAL TAURIDS, TURKEY

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Ali SARI

2012-06-01

Full Text Available - Late Jurassic-Early Cretaceous Akkuyu formation was deposited in a marine carbonate platform in Central Tarurids. The organic material of the unit is composed of Type III kerogen which is woody material transported from the land. Late Jurassic- Early Cretaceous is an important period which great anoxic events in deep sea bottom occurred due to the primary organic productivity in global sea surface. Use of several trace elements values (Ni, V, U, Cr, Co, Th revealed that Late Jurassic-Early Cretaceous Akkuyu formation shows oxic, disoxic and anoxic paleoredox conditions. In this period the primary productivity was considerably high. Examination of specimen derived from Akkuyu formation revealed that there exists a very good positive relationship between the major oxides of Al2O3, SiO2, Fe2O3, TiO2, and K2O. These combinations of major oxides indicate a detrital origin of source rock. Chemical weathering evaluations of Central Taurids in the Jurassic-Cretaceous period indicated moderate and strong weathering of source rock. K2O/Na2O versus SiO2; SiO2/Al2O3 versus K2O/Na2O; Al2O3/ SiO2 versus Fe2O3 + MgO ve TiO2 versus Fe2O3 + MgO diagrams indicated that Akkuyu formation was deposited along active and/or passive continental margin and derived from basalt and basalt+granite mixed rocks.

Stratigraphy and macrofauna of the Lower Jurassic (Toarcian) Marrat Formation, central Saudi Arabia

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El-Sorogy, Abdelbaset S.; Gameil, Mohamed; Youssef, Mohamed; Al-Kahtany, Khaled M.

2017-10-01

The stratigraphy and macrofaunal content of the Lower Jurassic (Toarcian) Marrat Formation was studied at Khashm adh Dhibi, central Saudi Arabia. The studied succession is dominated by limestones and dolomites, with subordinate occurrences of sandstones, siltstones and claystones. The formation is highly fossiliferous with brachiopods, gastropods, bivalves, ammonites and echinoids, particularly the lower and upper members. Twenty nine species are identified, they include 7 species of brachiopods, 8 gastropods, 8 bivalves, 4 ammonites and 2 echinoids. Many of the identified fauna are correlated with Jurassic equivalents in Jordan, Italy, Morocco, Egypt and India. Three gastropod species: Globularia subumbilicata, Ampullospira sp., Purpuroidea peristriata and seven bivalve species: Palaeonucula lateralis, Chlamys (Radulopecten) fibrosa, Eligmus weiri, E.integer, E. asiaticus, Musculus somaliensis and Pholadomya orientalis were recognized for the first time in the Lower Jurassic deposits of Saudi Arabia.

Geologic controls on the formation of lakes in north-central Florida

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Kindinger, Jack G.; Davis, Jeffrey B.; Flocks, James G.; Pitman, Janet K.; Carroll, Alan R.

1998-01-01

Fluid exchange between surficial waters and groundwater, as well as the processes that control this exchange, are of critical concern to water management districts and planners. Digital high-resolution seismic systems were used to collect geophysical data from 30 lakes of north-central Florida. Although using seismic profile data in the past has been less than successful, the use of digital technology has increased the potential for success. Seismic profiles collected from the lakes of north-central Florida have shown the potential application of these techniques in understanding the formation of individual lakes. In each case study, lake structure and geomorphology were controlled by solution and/or mechanical processes. Processes that control lake development are twofold: 1) karstification or dissolution of the underlying limestone, and 2) me collapse, subsidence, or slumping of overburden to form sinkholes. Initial lake formation is directly related to the karst topography of the underlying host limestone. Lake size and shape are a factor of the thickness of overburden and size of the collapse or subsidence and/or clustering of depressions allowing for lake development. Lake development is through progressive sequence stages to maturity that can be delineated into geomorphic types. Case studies have shown that lakes can be divided by geomorphic types into progressive developmental phases: (1) active subsidence or collapse phase (young) - the open to partially filled collapse structures typically associated with sink holes; (2) transitional phase (middle age) - the sinkhole is plugged as the voids within the collapse are filled with sediment, periodic reactivation may occur; (3) baselevel phase (mature) - active sinkholes are progressively plugged by the continual erosion of material into the basin, and eventually sediment fills the basins; and (4) polje (drowned prairie) - broad flat-bottom basins located within the epiphreatic zone that are inundated at high

Territorial dynamics and stable home range formation for central place foragers.

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Jonathan R Potts

Full Text Available Uncovering the mechanisms behind territory formation is a fundamental problem in behavioural ecology. The broad nature of the underlying conspecific avoidance processes are well documented across a wide range of taxa. Scent marking in particular is common to a large range of terrestrial mammals and is known to be fundamental for communication. However, despite its importance, exact quantification of the time-scales over which scent cues and messages persist remains elusive. Recent work by the present authors has begun to shed light on this problem by modelling animals as random walkers with scent-mediated interaction processes. Territories emerge as dynamic objects that continually change shape and slowly move without settling to a fixed location. As a consequence, the utilisation distribution of such an animal results in a slowly increasing home range, as shown for urban foxes (Vulpes vulpes. For certain other species, however, home ranges reach a stable state. The present work shows that stable home ranges arise when, in addition to scent-mediated conspecific avoidance, each animal moves as a central place forager. That is, the animal's movement has a random aspect but is also biased towards a fixed location, such as a den or nest site. Dynamic territories emerge but the probability distribution of the territory border locations reaches a steady state, causing stable home ranges to emerge from the territorial dynamics. Approximate analytic expressions for the animal's probability density function are derived. A programme is given for using these expressions to quantify both the strength of the animal's movement bias towards the central place and the time-scale over which scent messages persist. Comparisons are made with previous theoretical work modelling central place foragers with conspecific avoidance. Some insights into the mechanisms behind allometric scaling laws of animal space use are also given.

Formation of well-mixed warm water column in central Bohai Sea during summer: Role of high-frequency atmospheric forcing

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Ma, Weiwei; Wan, Xiuquan; Wang, Zhankun; Liu, Yulong; Wan, Kai

2017-12-01

The influence of high-frequency atmospheric forcing on the formation of a well-mixed summer warm water column in the central Bohai Sea is investigated comparing model simulations driven by daily surface forcing and those using monthly forcing data. In the absence of high-frequency atmospheric forcing, numerical simulations have repeatedly failed to reproduce this vertically uniform column of warm water measured over the past 35 years. However, high-frequency surface forcing is found to strongly influence the structure and distribution of the well-mixed warm water column, and simulations are in good agreement with observations. Results show that high frequency forcing enhances vertical mixing over the central bank, intensifies downward heat transport, and homogenizes the water column to form the Bohai central warm column. Evidence presented shows that high frequency forcing plays a dominant role in the formation of the well-mixed warm water column in summer, even without the effects of tidal and surface wave mixing. The present study thus provides a practical and rational way of further improving the performance of oceanic simulations in the Bohai Sea and can be used to adjust parameterization schemes of ocean models.

Organic Geochemistry of the Cenomanian-Turonian Bahloul Formation Petroleum Source Rock, Central and Northern Tunisia

OpenAIRE

Affouri , Hassene; Montacer , Mabrouk; Disnar , Jean-Robert

2013-01-01

International audience; Total organic carbon (TOC) determination, Rock-Eval pyrolysis, extractable organic matter content (EOM) fractionation, gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analyses, were carried out on 79 samples from eleven outcrop cross sections of the Bahloul Formation in central and northern Tunisia. The TOC content varied between 0.23 to 35.6%, the highest average values (18.73%, 8.46% and 4.02%) being at the east of the study area (at Ain Zakk...

Depositional architecture and sequence stratigraphy of the Upper Jurassic Hanifa Formation, central Saudi Arabia

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El-Sorogy, Abdelbaset; Al-Kahtany, Khaled; Almadani, Sattam; Tawfik, Mohamed

2018-03-01

To document the depositional architecture and sequence stratigraphy of the Upper Jurassic Hanifa Formation in central Saudi Arabia, three composite sections were examined, measured and thin section analysed at Al-Abakkayn, Sadous and Maashabah mountains. Fourteen microfacies types were identified, from wackestones to boundstones and which permits the recognition of five lithofacies associations in a carbonate platform. Lithofacies associations range from low energy, sponges, foraminifers and bioclastic burrowed offshoal deposits to moderate lithoclstic, peloidal and bioclastic foreshoal deposits in the lower part of the Hanifa while the upper part is dominated by corals, ooidal and peloidal high energy shoal deposits to moderate to low energy peloidal, stromatoporoids and other bioclastics back shoal deposits. The studied Hanifa Formation exhibits an obvious cyclicity, distinguishing from vertical variations in lithofacies types. These microfacies types are arranged in two third order sequences, the first sequence is equivalent to the lower part of the Hanifa Formation (Hawtah member) while the second one is equivalent to the upper part (Ulayyah member). Within these two sequences, there are three to six fourth-order high frequency sequences respectively in the studied sections.

Glycinergic Pathways of the Central Auditory System and Adjacent Reticular Formation of the Rat.

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Hunter, Chyren

The development of techniques to visualize and identify specific transmitters of neuronal circuits has stimulated work on the characterization of pathways in the rat central nervous system that utilize the inhibitory amino acid glycine as its neurotransmitter. Glycine is a major inhibitory transmitter in the spinal cord and brainstem of vertebrates where it satisfies the major criteria for neurotransmitter action. Some of these characteristics are: uneven distribution in brain, high affinity reuptake mechanisms, inhibitory neurophysiological actions on certain neuronal populations, uneven receptor distribution and the specific antagonism of its actions by the convulsant alkaloid strychnine. Behaviorally, antagonism of glycinergic neurotransmission in the medullary reticular formation is linked to the development of myoclonus and seizures which may be initiated by auditory as well as other stimuli. In the present study, decreases in the concentration of glycine as well as the density of glycine receptors in the medulla with aging were found and may be responsible for the lowered threshold for strychnine seizures observed in older rats. Neuroanatomical pathways in the central auditory system and medullary and pontine reticular formation (RF) were investigated using retrograde transport of tritiated glycine to identify glycinergic pathways; immunohistochemical techniques were used to corroborate the location of glycine neurons. Within the central auditory system, retrograde transport studies using tritiated glycine demonstrated an ipsilateral glycinergic pathway linking nuclei of the ascending auditory system. This pathway has its cell bodies in the medial nucleus of the trapezoid body (MNTB) and projects to the ventrocaudal division of the ventral nucleus of the lateral lemniscus (VLL). Collaterals of this glycinergic projection terminate in the ipsilateral lateral superior olive (LSO). Other glycinergic pathways found were afferent to the VLL and have their origin

Rodents from the Upper Miocene Tuğlu Formation (Çankırı Basin, Central Anatolia, Turkey)

NARCIS (Netherlands)

Joniak, Peter; de Bruijn, Hans

2015-01-01

The upper Miocene assemblages of rodents collected from two layers of the type section of the Tuğlu Formation (Çankırı Basin, Central Anatolia, Turkey) are described. The assemblage from the lower level is considerably less diverse than that from the upper level. It contains Progonomys together with

Facies distribution, depositional environment, and petrophysical features of the Sharawra Formation, Old Qusaiba Village, Central Saudi Arabia

Science.gov (United States)

Abbas, Muhammad Asif; Kaminski, Michael; Umran Dogan, A.

2016-04-01

The Silurian Sharawra Formation has great importance as it rests over the richest source rock of the Qusaiba Formation in central Saudi Arabia. The Sharawra Formation has four members including Jarish, Khanafriyah, Nayyal, and Zubliyat. The formation mainly consists of sandstone and siltstone with subordinate shale sequences. The lack of published research on this formation requires fundamental studies that can lay the foundation for future research. Three outcrops were selected from the Old Qusaiba Village in Central Saudi Arabia for field observations, petrographical and petrophysical study. Thin section study has been aided by quantitative mineralogical characterization using scanning electron microscopy - energy dispersive spectroscopy and powder x-ray diffraction (XRD) for both minerals, cements, and clay minerals (detrital and authigenic). The outcrops were logged in detail and nine different lithofacies have been identified. The thin section study has revealed the Sharawra Formation to be mainly subarkosic, while the mica content increases near to its contact with the Qusaiba Formation. The XRD data has also revealed a prominent change in mineralogy with inclusion of minerals like phlogopite and microcline with depths. Field observations delineated a prominent thinning of strata as lithofacies correlation clearly shows the thinning of strata in the southwestern direction. The absence of outcrop exposures further supports the idea of southwestern thinning of strata. This is mainly attributed to local erosion and the presence of thicker shale interbeds in the southeastern section, which was probably subjected to more intense erosion than the northwestern one. The Sharawra Formation rests conformably over the thick transgressive shale sequence, deposited during the post glacial depositional cycle. The lowermost massive sandstone bed of the Sharawra Formation represents the beginning of the regressive period. The shale interbeds in the lower part are evidence of

An assessment on CO2 geosequestration in deep saline formations in the Taihsi Basin, central Taiwan

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Cai, Mo-Si; Lin, Andrew T.; Fan, Jhen-Huei

2015-04-01

Geological storage of carbon dioxide (CO2) is to inject and store a large amount of anthropogenic CO2 in deep and sealed porous rocks in order to mitigate the aggravated threat of global climate changes. Borehole and reflection seismic data are used to understand the spatial distribution of suitable CO2 reservoirs and cap rocks in the Taihsi Basin, central Taiwan, where the level of seismicity is low. The Taihsi Basin was a rift basin during the Paleocene to Eocene, followed by a phase of post-rift subsidence during late Oligocene to late Miocene. The loading of the Taiwan mountain belt since late Miocene has turned the Taihsi Basin into a peripheral foreland basin, with strata gently dipping toward the mountain belts in the east. The coastal plain in central Taiwan (Changhua and Yunlin Counties) and its adjacent offshore areas are close to major CO2 emission sources and no active geological structures are found in these areas, making the study area a favorable CO2 storage site. Spatial distribution of formation thickness and depth for CO2 reservoirs and cap rocks indicates three CO2 storage systems existed in the study area. They are: (1) late Miocene to Pliocene Nanchuang Formation and Kueichulin Formation (reservoirs)-Chinshui Shale (seals) system (hereafter abbreviated as NK-C system), (2) early to middle Miocene Shihti Formation and Peiliao Formation (reservoirs)-Talu Shale (seals) system (SP-T system), (3) early Miocene Mushan Formation (reservoirs)-Piling Shale (seals) system (M-P system). The NK-C system contains multiple layers of porous sandstones from Nanchuang and Kueichulin formations, with total thickness around 210-280 m. In the vicinity of the northern bank of the Jhuoshuei River, reservoir top reaches a depth around 1850 m, with 60 m thick seal formation, the Chinshui Shale. However, the Chinshui Shale becomes sand-prone in the Changhua coastal and nearshore areas due to facies changes. The SP-T system consists of two porous sandstone layers from

Comparison of atmospheric new particle formation events in three Central European cities

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Németh, Zoltán; Rosati, Bernadette; Zíková, Naděžda; Salma, Imre; Bozó, László; Dameto de España, Carmen; Schwarz, Jaroslav; Ždímal, Vladimír; Wonaschütz, Anna

2018-04-01

Simultaneous particle number size distribution measurements were performed in the urban environment of Budapest, Vienna, and Prague, three Central European cities located within 450 km of each other. The measurement days from the continuous, 2-year long campaign were classified for new particle formation (NPF) events using an adapted classification scheme for urban sites. The total numbers of NPF event days were 152 for Budapest, 69 for Vienna, and 143 for Prague. There were 12 days when new particle formation took place at all three sites; 11 out of these 12 days were in spring and in summer. There were only 2 (Budapest-Vienna), 19 (Budapest-Prague), and 19 (Vienna-Prague) nucleation days, when NPF did not occur on the third site. The main difference was related to source and sink terms of gas-phase sulphuric acid. Air mass origin and back-trajectories did not show any substantial influence on the atmospheric nucleation phenomena. The relative contribution of particles from NPF with respect to regional aerosol to the particles originating from all sources was expressed as nucleation strength factor. The overall mean nucleation strength factors were 1.58, 1.54, and 2.01 for Budapest, Vienna, and Prague, respectively, and showed diurnal and seasonal variations. The monthly mean NSF varied from 1.2 to 3.2 in Budapest, from 0.7 to 1.9 in Vienna, and from 1.0 to 2.3 in Prague. This implies that the new particle formation in cities is a significant source of ultrafine (UF) particles, and the amount of them is comparable to the directly emitted UF particles.

Depositional environments and sequence stratigraphy of the Bahram Formation (middle–late Devonian in north of Kerman, south-central Iran

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Afshin Hashmie

2016-09-01

Full Text Available This study is focused on sedimentary environments, facies distribution, and sequence stratigraphy. The facies and sequence stratigraphic analyses of the Bahram Formation (middle–late Devonian in south-central Iran are based on two measured stratigraphic sections in the southern Tabas block. The Bahram Formation overlies red sandstones Padeha Formation in sections Hutk and Sardar and is overlain by Carboniferous carbonate deposits of Hutk Formation paraconformably, with a thickness of 354 and 386 m respectively. Mixed siliciclastic and carbonate sediments are present in this succession. The field observations and laboratory studies were used to identify 14 micro/petrofacies, which can be grouped into 5 depositional environments: shore, tidal flat, lagoon, shoal and shallow open marine. A mixed carbonate-detrital shallow shelf is suggested for the depositional environment of the Bahram Formation which deepens to the east (Sardar section and thins in southern locations (Hutk section. Three 3rd-order cyclic siliciclastic and carbonate sequences in the Bahram Formation and one sequence shared with the overlying joint with Hutk Formation are identified, on the basis of shallowing upward patterns in the micro/pertofacies.

Microfacies, Sedimentary Environment and Relative Sea Level Changes of the Ruteh Formation, Sangsar and Makaroud Sections, Central Alborz

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Leili Bastami

2016-12-01

Full Text Available Introduction According to different paleontological and paleomagnetic studies, Iran was part of the Gondwana during the Permian. The Permian lithostratigraphic units in the Alborz-Azerbaijan are introduced as Doroud, Ruteh and Nesen Formations. The Ruteh Formation, the second depositional cycle of the Permian in the Alborz Basin, have been studied at two stratigraphic sections in the Central Alborz. The Sangsar section located on the south flank of the Central Alborz, 1 km northwest of Mahdishahr city and the Makaroud section located on the north flank of the Central Alborz, about 37 km south of Chalous city. The thickness of the Ruteh Formation at the Sangsar section is 106 m and at the Makaroud section is 222 m. At the Sangsar section the Ruteh Formation is underlain by the Doroud Formation with gradual contact and is overlain by a lateritic horizon. At the Makaroud section the Ruteh Formation disconformably overlies the Doroud Formation and the upper boundary is faulted and the Chalous Formation overlies the Ruteh Formation at this section. The aim of this paper is to analysis microfacies, interpret depositional environments and delineate relative sea level changes of the Ruteh Formation. Other researchers studied the Ruteh Formation at different sections in the Alborz Basin believe that the carbonate sediments of this formation have been deposited in a homoclinal carbonate ramp and consist of two-three 3rd order depositional sequences. But no sedimentological studies have been done at the selected sections in this study.   Material & Methods Two stratigraphic sections of the Ruteh Formation have been selected, measuted and sampled. One hundred sixty three samples (fifty seven samples from Sangsar and one hundred six samples from Makaroud section  were collected and thin sections were prepared from all samples. Afew samples were collected from lower and upper formations. Thin sections were stained with potassium ferricyanide and alizarin

The crazy hollow formation (Eocene) of central Utah

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Weiss, M.P.; Warner, K.N.

2001-01-01

The Late Eocene Crazy Hollow Formation is a fluviatile and lacustrine unit that was deposited locally in the southwest arm of Lake Uinta during and after the last stages of the lake the deposited the Green River Formation. Most exposures of the Crazy Hollow are located in Sanpete and Sevier Counties. The unit is characterized by a large variety of rock types, rapid facies changes within fairly short distances, and different lithofacies in the several areas where outcrops of the remnants of the formation are concentrated. Mudstone is dominant, volumetrically, but siltstone, shale, sandstone, conglomerate and several varieties of limestone are also present. The fine-grained rocks are mostly highly colored, especially in shades of yellow, orange and red. Sand grains, pebbles and small cobbles of well-rounded black chert are widespread, and "salt-and-pepper sandstone" is the conspicuous characteristic of the Crazy Hollow. The salt-and-pepper sandstone consists of grains of black chert, white chert, quartz and minor feldspar. The limestone beds and lenses are paludal and lacustrine in origin; some are fossiliferous, and contain the same fauna found in the Green River Formation. With trivial exceptions, the Crazy Hollow Formation lies on the upper, limestone member of the Green River Formation, and the beds of the two units are always accordant in attitude. The nature of the contact differs locally: at some sites there is gradation from the Green River to the Crazy Hollow; at others, rocks typical of the two units intertongue; elsewhere there is a disconformity between the two. A variety of bedrock units overlie the Crazy Hollow at different sites. In the southeasternmost districts it is overlain by the late Eocene formation of Aurora; in western Sevier County it is overlain by the Miocene-Pliocene Sevier River Formation; in northernmost Sanpete County it is overlain by the Oligocene volcanics of the Moroni Formation. At many sites bordering Sanpete and Sevier Valleys

The Jurassic of Denmark and Greenland: Sedimentology and sequence stratigraphy of the Bryne and Lulu Formations, Middle Jurassic, northern Danish Central Graben

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Andsbjerg, Jan

2003-10-01

Full Text Available The Middle Jurassic Bryne and Lulu Formations of the Søgne Basin (northern part of the Danish Central Graben consist of fluvially-dominated coastal plain deposits, overlain by interfingering shoreface and back-barrier deposits. Laterally continuous, mainly fining-upwards fluvial channel sandstones that locally show evidence for tidal influence dominate the alluvial/coastal plain deposits of the lower Bryne Formation. The sandstones are separated by units of fine-grained floodplain sediments that show a fining-upwards - coarsening-upwards pattern and locally grade into lacustrine mudstones. A regional unconformity that separates the lower Bryne Formation from the mainly estuarine upper Bryne Formation is defined by the strongly erosional base of a succession of stacked channel sandstones, interpreted as the fill of a system of incised valleys. Most of the stacked channel sandstones show abundant mud laminae and flasers, and rare herringbone structures, suggesting that they were deposited in a tidal environment, probably an estuary. Several tens of metres of the lower Bryne Formation may have been removed by erosion at this unconformity. The estuarine channel sandstone succession is capped by coal beds that attain a thickness of several metres in the western part of the Søgne Basin, but are thin and poorly developed in the central part of the basin. Above the coal beds, the Lulu Formation is dominated by various types of tidally influenced paralic deposits in the western part of the basin and by coarsening-upwards shoreface and beach deposits in central parts. Westwards-thickening wedges of paralic deposits interfinger with eastwards-thickening wedges of shallow marine deposits. The Middle Jurassic succession is subdivided into nine sequences. In the lower Bryne Formation, sequence boundaries are situated at the base of laterally continuous fluvial channel sandstones whereas maximum flooding surfaces are placed in laterally extensive floodplain

The Lower Triassic Sorkh Shale Formation of the Tabas Block, east central Iran: Succesion of a failed-rift basin at the Paleotethys margin

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Lasemi, Y.; Ghomashi, M.; Amin-Rasouli, H.; Kheradmand, A.

2008-01-01

The Lower Triassic Sorkh Shale Formation is a dominantly red colored marginal marine succession deposited in the north-south trending Tabas Basin of east central Iran. It is correlated with the unconformity-bounded lower limestone member of the Elika Formation of the Alborz Mountains of northern Iran. The Sorkh Shale is bounded by the pre-Triassic and post-Lower Triassic interregional unconformities and consists mainly of carbonates, sandstones, and evaporites with shale being a minor constituent. Detailed facies analysis of the Sorkh Shale Formation resulted in recognition of several genetically linked peritidal facies that are grouped into restricted subtidal, carbonate tidal flat, siliciclastic tidal flat, coastal plain and continental evaporite facies associations. These were deposited in a low energy, storm-dominated inner-ramp setting with a very gentle slope that fringed the Tabas Block of east central Iran and passed northward (present-day coordinates) into deeper water facies of the Paleotethys passive margin of northern Cimmerian Continent. Numerous carbonate storm beds containing well-rounded intraclasts, ooids and bioclasts of mixed fauna are present in the Sorkh Shale Formation of the northern Tabas Basin. The constituents of the storm beds are absent in the fair weather peritidal facies of the Sorkh Shale Formation, but are present throughout the lower limestone member of the Elika Formation. The Tabas Block, a part of the Cimmerian continent in east central Iran, is a rift basin that developed during Early Ordovician-Silurian Paleotethys rifting. Facies and sequence stratigraphic analyses of the Sorkh Shale Formation has revealed additional evidence supporting the Tabas Block as a failed rift basin related to the Paleotethys passive margin. Absence of constituents of the storm beds in the fair weather peritidal facies of the Sorkh Shale Formation, presence of the constituents of the storm beds in the fair weather facies of the Elika Formation (the

Paleomagnetism of the Puente Piedra Formation, Central Peru

Science.gov (United States)

May, Steven R.; Butler, Robert F.

1985-02-01

Paleomagnetic samples were collected from 15 sites in the early Cretaceous Puente Piedra Formation near Lima, Peru. This formation consists of interbedded volcanic flows and marine sediments and represents the oldest known rocks of the Andean coastal province in this region. The Puente Piedra Formation is interpreted as a submarine volcanic arc assemblage which along with an overlying sequence of early Cretaceous clastic and carbonate rocks represents a terrane whose paleogeographic relationship with respect to the Peruvian miogeocline in pre-Albian time is unknown. Moderate to high coercivities, blocking temperatures below 320°C, and diagnostic strong-field thermomagnetic behavior indicate that pyrrhotite is the dominant magnetic phase in the Puente Piedra Formation. This pyrrhotite carries a stable CRM acquired during an event of copper mineralization associated with the intrusion of the Santa Rosa super-unit of the Coastal Batholith at about 90 ± 5 m.y. B.P. The tectonically uncorrected formation mean direction of: D = 343.2°, I = -28.6°, α 95 = 3.4° is statistically concordant in inclination but discordant in declination with respect to the expected direction calculated from the 90-m.y. reference pole for cratonic South America. The observed declination indicates approximately 20° of counterclockwise rotation of the Puente Piedra rocks since about 90 m.y. This is consistent with other paleomagnetic data from a larger crustal block which may indicate modest counterclockwise rotation during the Cenozoic associated with crustal shortening and thickening in the region of the Peru-Chile deflection.

GLAUBERITE-HALITE ASSOCIATION IN BOZKIR FORMATION (PLİOCENE, ÇANKIRI-ÇORUM BASİN, CENTRAL ANATOLİA, TURKEY

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İLHAN SÖNMEZ

2015-06-01

Full Text Available Tertiary Çankırı – Çorum Basin is one of the biggest basin covering evaporitic formationsin the Central Anatolia. During borehole drills carried out in Bozkır Formation whichcontain Pliocene aged evaporites in the basin, a thick rocksalt (halite, NaCl deposit wasdetected that consisting of glauberite (Na2Ca(SO42 interlayers (sabhka synchronouswith sedimentation. Rocksalt bearing layers in Bozkır formation which was deposited inplaya-lake – sabhka environment, where seasonal changes are effective, were first definedas Tuz member in this study. Bozkır formation was divided into three zones in drillingscarried out in sabhka – playa -lake transitional environment. From bottom to top, these areordered as claystone-less anhydrite zone, rock salt-claystone-anhydrite-glauberite zone(Tuz member and claystone-gypsum-less anhydrite zone. Rocksalt was cut in thicknessesreaching 115 meters within Tuz member. Rocksalt (playa-lake which is mostly bedded andwhite, pale/dark gray colored is conformable with sedimentation and is low dipping. The1. Girifl

Graben formation during the Bárðarbunga rifting event in central Iceland

KAUST Repository

Ruch, Joel

2015-04-01

On the 16th of August 2014, an intense seismic swarm was detected at the Bárðarbunga caldera (central Iceland), which migrated to the east and then to the northeast during the following days. The swarm, highlighting magma propagation pathway from the caldera, migrated laterally during the following two weeks over 40 km. By the end of August, a volcanic eruption had started along a north-south oriented fissure located ~45 km from the caldera. Here we focus on the near-field deformation related to the dike emplacement in the shallow crust, which generated in few days an 8 km long by 0.8 km wide graben (depression) structure. The new graben extends from the northern edge of the Vatnajökull glacier and to the north to the eruptive fissure. We analyze the temporal evolution of the graben by integrating structural mapping using multiple acquisitions of TerraSAR-X amplitude radar images, InSAR and ground-truth data with GPS and structural measurements. Pixel-offset tracking of radar amplitude images shows clearly the graben subsidence, directly above the intrusion pathway, of up to 6 meters in the satellite line-of-sight direction. We installed a GPS profile of 15 points across the graben in October 2014 and measured its depth up to 8 meters, relative to the flanks of the graben. Field structural observations show graben collapse structures that typically accompany dike intrusions, with two tilted blocks dipping toward the graben axis, bordered by two normal faults. Extensive fractures at the center of the graben and at the graben edges show a cumulative extension of ~8 meters. The formation of the graben was also accompanied by strong seismic activity locally, constraining the time frame period of the main graben formation subsidence. Our results show a rare case of a graben formation captured from space and from ground observations. Such structures are the dominant features along rift zones, however, their formation remain poorly understood. The results also provide

Star-disc interaction in galactic nuclei: formation of a central stellar disc

Science.gov (United States)

Panamarev, Taras; Shukirgaliyev, Bekdaulet; Meiron, Yohai; Berczik, Peter; Just, Andreas; Spurzem, Rainer; Omarov, Chingis; Vilkoviskij, Emmanuil

2018-05-01

We perform high-resolution direct N-body simulations to study the effect of an accretion disc on stellar dynamics in an active galactic nucleus (AGN). We show that the interaction of the nuclear stellar cluster (NSC) with the gaseous accretion disc (AD) leads to formation of a stellar disc in the central part of the NSC. The accretion of stars from the stellar disc on to the super-massive black hole is balanced by the capture of stars from the NSC into the stellar disc, yielding a stationary density profile. We derive the migration time through the AD to be 3 per cent of the half-mass relaxation time of the NSC. The mass and size of the stellar disc are 0.7 per cent of the mass and 5 per cent of the influence radius of the super-massive black hole. An AD lifetime shorter than the migration time would result in a less massive nuclear stellar disc. The detection of such a stellar disc could point to past activity of the hosting galactic nucleus.

Geoarchaeological investigation at Al-Khiday (central Sudan): late Quaternary palaeoenvironment and site formation

Science.gov (United States)

Zerboni, Andrea; Usai, Donatella; Salvatori, Sandro

2010-05-01

The micromorphological investigation on several pluristratified archaeological sites in central Sudan (Al-Khiday, left bank of the White Nile, Khartoum region, Sudan) permitted to elucidate depositional and post-depositional processes playing a role in the formation and preservation of the archaeological record. At Al-Khiday sites are located at the top of small mounds, representing the remains of Pleistocene sandy fluvial bars, and were attended since the beginning of the Holocene. The first occupation of the area corresponds to a pre-Mesolithic cemetery; than Mesolithic groups lived upon the mounds and their occupation is testified by several archaeological features: pits filled by ash and bones and living floors. Preserved Neolithic features are scarce and limited to few graves (V millennium BC). After this phase, a long gap in human attendance is registered, during which wind continued to dismantling the mounds and the sites; at ca. 2000 years BP Meroitic/Post-Meroitic groups built their tombs at the top of the archaeological sequences and altered most of the stratigraphic record. Thanks to micromorphology, it was possible to distinguish between archaeological strata still in situ and those disturbed by natural and anthropic processes; furthermore, this approach allowed to interpret the significance of several archaeological features (living floors, fireplaces, and garbage pits). In this case micromorphology of archaeological deposits was a key tool to reconstruct the depositional and post-depositional processes that contributed to the formation and preservation of the archaeological record.

Rodents from the Upper Miocene Tuğlu Formation (Çankırı Basin, Central Anatolia, Turkey)

OpenAIRE

Joniak, Peter; de Bruijn, Hans

2015-01-01

The upper Miocene assemblages of rodents collected from two layers of the type section of the Tuğlu Formation (Çankırı Basin, Central Anatolia, Turkey) are described. The assemblage from the lower level is considerably less diverse than that from the upper level. It contains Progonomys together with Megacricetodon, which is a very unusual association. The assemblage from the upper layer shows a relatively high diversity with four species of Gliridae instead of only one in the lower layer. Apa...

The two young star disks in the central parsec of the Galaxy: properties, dynamics, and formation

International Nuclear Information System (INIS)

Paumard, T; Genzel, R; Martins, F; Nayakshin, S; Beloborodov, A M; Levin, Y; Trippe, S; Eisenhauer, F; Ott, T; Gillessen, S; Abuter, R; Cuadra, J; Alexander, T; Sternberg, A

2006-01-01

We report the definite spectroscopic identification of ≅ 40 OB supergiants, giants and main sequence stars in the central parsec of the Galaxy. Detection of their absorption lines have become possible with the high spatial and spectral resolution and sensitivity of the adaptive optics integral Held spectrometer SPIFFI/SINFONI on the ESO VLT. Several of these OB stars appear to be helium and nitrogen rich. Almost all of the ≅80 massive stars now known in the central parsec (central arcsecond excluded) reside in one of two somewhat thick ((|/R) ≅ 0.14) rotating disks. These stellar disks have fairly sharp inner edges (R ≅ 1'') and surface density profiles that scale as R -2 . We do not detect any OB stars outside the central 0.5 pc. The majority of the stars in the clockwise system appear to be on almost circular orbits, whereas most of those in the 'counter-clockwise' disk appear to be on eccentric orbits. Based on its stellar surface density distribution and dynamics we propose that IRS 13E is an extremely dense cluster (ρ core ∼> 3 x 10 8 M o-dot pc -3 ), which has formed in the counter-clockwise disk. The stellar contents of both systems are remarkably similar, indicating a common age of ≅ 6±2 Myr. The K-band luminosity function of the massive stars suggests a top-heavy mass function and limits the total stellar mass contained in both disks to ≅ 1.5 x 10 4 M o-dot . Our data strongly favor in situ star formation from dense gas accretion disks for the two stellar disks. This conclusion is very clear for the clockwise disk and highly plausible for the counter-clockwise system

Origin of acid orthoderived and paraderived geologic formations of the central part of the province of Limousin (France). A possible source for uraniferous leucogranite

International Nuclear Information System (INIS)

Bourguignon, A.

1988-01-01

Important metamorphic formations of the central part of the province of Limousin are studied by chemical investigations for characterization of their primary signature. Four large orthoderived formations are compared: Dronne, Meuzac, and Thaurion arcs and leptynite formations. The typology of the parent magmatism of orthogneiss and leptynite allows to find leack most of plutonic associations known in the Variscan chain (subalkaline, calcoalkaline, aluminous). Interpretation of primary geochemical fractionation in rocks from the Dronne are suggests cogenetism of the whole facies following a fractionated crystallization process. Moreover rocks from the Dronne arc have a peraluminous character with high U and Th content related to subalkaline magmatism which make of them a potential source of uraniferous peraluminous leucogranites. Paraderived formations are represented by 3 mica schist formations and 2 gneiss formations. Each unit is individualized by geochemical study of mica schist. Gneiss formation are chemically distinct. These differences confirm that they belong to distinct lithologic units. Trace elements are used to precise the paleogeotectonic context of original sediment deposition [fr

Ice formation in subglacial Lake Vostok, Central Antarctica

Science.gov (United States)

Souchez, R.; Petit, J. R.; Tison, J.-L.; Jouzel, J.; Verbeke, V.

2000-09-01

The investigation of chemical and isotopic properties in the lake ice from the Vostok ice core gives clues to the mechanisms involved in ice formation within the lake. A small lake water salinity can be reasonably deduced from the chemical data. Possible implications for the water circulation of Lake Vostok are developed. The characteristics of the isotopic composition of the lake ice indicate that ice formation in Lake Vostok occurred by frazil ice crystal generation due to supercooling as a consequence of rising waters and a possible contrast in water salinity. Subsequent consolidation of the developed loose ice crystals results in the accretion of ice to the ceiling of the lake.

THE NATURE OF STARBURSTS. III. THE SPATIAL DISTRIBUTION OF STAR FORMATION

Energy Technology Data Exchange (ETDEWEB)

McQuinn, Kristen B. W.; Skillman, Evan D. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, S.E., University of Minnesota, Minneapolis, MN 55455 (United States); Dalcanton, Julianne J.; Weisz, Daniel R.; Williams, Benjamin F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Cannon, John M. [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 E. Hermans Road, Tucson, AZ 85756 (United States); Holtzman, Jon, E-mail: kmcquinn@astro.umn.edu [Department of Astronomy, New Mexico State University, Box 30001-Department 4500, 1320 Frenger Street, Las Cruces, NM 88003 (United States)

2012-11-01

We map the spatial distribution of recent star formation over a few Multiplication-Sign 100 Myr timescales in 15 starburst dwarf galaxies using the location of young blue helium burning stars identified from optically resolved stellar populations in archival Hubble Space Telescope observations. By comparing the star formation histories from both the high surface brightness central regions and the diffuse outer regions, we measure the degree to which the star formation has been centrally concentrated during the galaxies' starbursts, using three different metrics for the spatial concentration. We find that the galaxies span a full range in spatial concentration, from highly centralized to broadly distributed star formation. Since most starbursts have historically been identified by relatively short timescale star formation tracers (e.g., H{alpha} emission), there could be a strong bias toward classifying only those galaxies with recent, centralized star formation as starbursts, while missing starbursts that are spatially distributed.

Paleoenvironment of Tanjung Formation Barito Basin- Central Kalimantan Based on palynological data

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Winantris Winantris

2017-06-01

Full Text Available The research area is located in the Muara Teweh, North Barito, Central Kalimantan. The cocking coal deposits are well known as they were produced from this area.  Upper part of Tanjung Formation is target coal production. The study objectives are to analyze paleoenvironment and to determine the relative age of coal deposits based on palynological data. Preparing palinological analysis used standard procedure by hydrofluoric acid method.Palynomorphs data  grouped into six types of ecology, and the sequence is as follows ; fresh water and lowland (41,75 %, brackish water  swamp (30,10%, Peat and freshwater swamp (17,96%, marine element (7,77 %, back mangrove (1,46% and upland element (0,97. Palmae pollen is very dominant, especially from freshwater and peat swamp that grow around coastal area i.e. Dicolcopollis, Proxapertites cursus, Proxapertites operculatus, Longapertites and Palmaepollenites kutchensis. Although marine  fossil found, but the frequency  less than one percent,  that was the  evidence of influence sea water to swamp area. The palynomorphs indicate the coal sedimented at upper delta plain.  Fossil index of relative age consist of    Proxapertites cursus, Proxapertites operculatus, Magnastriatites howardi Verrucatosporites usmensis, Retistephanocolpites , and Ixonantes type which refer to Late Eocene.

Staphylococcus aureus sarA regulates inflammation and colonization during central nervous system biofilm formation.

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Jessica N Snowden

Full Text Available Infection is a frequent and serious complication following the treatment of hydrocephalus with CSF shunts, with limited therapeutic options because of biofilm formation along the catheter surface. Here we evaluated the possibility that the sarA regulatory locus engenders S. aureus more resistant to immune recognition in the central nervous system (CNS based on its reported ability to regulate biofilm formation. We utilized our established model of CNS catheter-associated infection, similar to CSF shunt infections seen in humans, to compare the kinetics of bacterial titers, cytokine production and inflammatory cell influx elicited by wild type S. aureus versus an isogenic sarA mutant. The sarA mutant was more rapidly cleared from infected catheters compared to its isogenic wild type strain. Consistent with this finding, several pro-inflammatory cytokines and chemokines, including IL-17, CXCL1, and IL-1β were significantly increased in the brain following infection with the sarA mutant versus wild type S. aureus, in agreement with the fact that the sarA mutant displayed impaired biofilm growth and favored a planktonic state. Neutrophil influx into the infected hemisphere was also increased in the animals infected with the sarA mutant compared to wild type bacteria. These changes were not attributable to extracellular protease activity, which is increased in the context of SarA mutation, since similar responses were observed between sarA and a sarA/protease mutant. Overall, these results demonstrate that sarA plays an important role in attenuating the inflammatory response during staphylococcal biofilm infection in the CNS via a mechanism that remains to be determined.

Central areolar choroidal dystrophy with associated dominant drusen

Directory of Open Access Journals (Sweden)

Julie Rodman

2013-04-01

Conclusion: Central areolar choroidal dystrophy normally presents without drusen. However, in patients manifesting a specific mutation, central areolar choridal dystrophy may present in conjunction with drusen. It appears that the Arg142Trp mutation is one of the factors predisposing to drusen formation.

The Pliocene Horcón Formation, Central Chile: a case study of earthquake-induced landslide susceptibility

Science.gov (United States)

Valdivia, D.; Elgueta, S.; Hodgkin, A.; Marquardt, C.; del Valle, F.; Yáñez Morroni, G.

2017-12-01

Stability slope analysis is typically focused on modeling using cohesion and friction angle parameters but in earthquake-induced landslides, susceptibility is correlated more to lithological and stratigraphic parameters. In sedimentary deposits whose cohesion and diagenesis are very low, the risk of landslides increases. The Horcón Formation, which crops out continuously along cliffs in Central Chile between 32.5° and 33°S, is a Miocene-Pliocene well preserved, horizontally stratified unit composed of marine strata which overlies Paleozoic-Mesozoic igneous basement. During the Quaternary, the sequence was tectonically uplifted 80 meters and covered by unconsolidated eolian deposits. Given that Seismotectonic and Barrier-Asperity models suggest the occurrence of a forthcoming megathrust earthquake in a segment which includes this area, the Horcón Formation constitutes a good case study to characterize the susceptibility of this type of sediment for mass movements triggered by earthquakes. Field mapping, stratigraphic and sedimentological studies, including petrographic analyses to determine lithological composition and paragenesis of diagenetic events, have been carried out along with limited gravimetric profiling and CPTU drill tests. High resolution digital elevation modeling has also been applied. This work has led to the recognition of a shallow marine lithofacies association composed of weakly lithified fossiliferous and bioturbated medium to fine grained litharenite, mudstone, and fine conglomerate. The low grade of diagenesis in the sedimentary deposits was in response to a short period of burial and a subsequent accelerated uplift evidenced along the coast of Chile during the Quaternary. We have generated a predictive model of landslide susceptibility for the Horcón Formation and for the overlying Quaternary eolian deposits incorporating variables such as composition and diagenesis of lithofacies, slope, structures, weathering and landcover. The model

Starbursts triggered by central overpressure in interacting galaxies

Science.gov (United States)

Jog, Chanda J.; Das, Mousumi

1993-01-01

A triggering mechanism for the origin of enhanced, massive-star formation in the central regions of interacting spiral galaxy pairs is proposed. Our mechanism is based on the detailed evolution of a realistic interstellar medium in a galaxy following an encounter. As a disk giant molecular cloud (GMC) tumbles into the central region following a galaxy encounter, it undergoes a radiative shock compression via the pre-existing high pressure of the central intercloud medium. The shocked outer shell of a GMC becomes gravitationally unstable and begins to fragment thus resulting in a burst of star formation, when the growth time for the gravitational instabilities in the shell becomes smaller than the crossing time of the shock. The resulting values of typical infrared luminosity agree with observations.

Dust formation and ionization in novae

International Nuclear Information System (INIS)

Yamamoto, Tetsuo; Sato, Shuji; Nariai, Kyoji.

1979-01-01

In order to explain the fact that some novae show the increase of infrared radiation indicating the formation of circumstellar dust grains while some others do not, the theory that the formation of dust in the circumstellar envelope of a nova depends on the intensity of ultraviolet radiation from a central star has been presented. It is known that the central star of a nova emits radiation at nearly constant rate, and its effective temperature rises. It was concluded that the novae with higher emission than a certain value are the poor candidates for dust formation because the whole envelope is ionized before dust is formed. But this conclusion is misleading. The evolution of the ultraviolet radiation emanating from a central star is summarized. The condensation of grains is possible when the partial pressure of the vapor, from which the grains are formed, becomes higher than the saturation vapor pressure. The temperature of grains can be estimated by equating the radiations absorbed and emitted. The grains evaporate if the grain temperature is higher than the condensation temperature. The formation of a Stroemgren sphere in the exploding envelope of a nova is discussed. For the formation of grains, it is necessary that temperature drops below the condensation temperature before the whole envelope is ionized. Hence dust grains do not grow if the grain temperature at a phase is higher than the condensation temperature. (Kako, I.)

Shale gas characterization based on geochemical and geophysical analysis: Case study of Brown shale, Pematang formation, Central Sumatra Basin

Science.gov (United States)

Haris, A.; Nastria, N.; Soebandrio, D.; Riyanto, A.

2017-07-01

Geochemical and geophysical analyses of shale gas have been carried out in Brown Shale, Middle Pematang Formation, Central Sumatra Basin. The paper is aimed at delineating the sweet spot distribution of potential shale gas reservoir, which is based on Total Organic Carbon (TOC), Maturity level data, and combined with TOC modeling that refers to Passey and Regression Multi Linear method. We used 4 well data, side wall core and 3D pre-stack seismic data. Our analysis of geochemical properties is based on well log and core data and its distribution are constrained by a framework of 3D seismic data, which is transformed into acoustic impedance. Further, the sweet spot of organic-rich shale is delineated by mapping TOC, which is extracted from inverted acoustic impedance. Our experiment analysis shows that organic materials contained in the formation of Middle Pematang Brown Shale members have TOC range from 0.15 to 2.71 wt.%, which is classified in the quality of poor to very good. In addition, the maturity level of organic material is ranging from 373°C to 432°C, which is indicated by vitrinite reflectance (Ro) of 0.58. In term of kerogen type, this Brown shale formation is categorized as kerogen type of II I III, which has the potential to generate a mixture of gasIoil on the environment.

The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin

Science.gov (United States)

Lopez-Gamundi, O. R.; Conaghan, P. J.; Rossello, E. A.; Cobbold, P. R.

1995-04-01

The Tunas Formation, extensively exposed in the Sierras Australes foldbelt of eastern central Argentina, completes the sedimentation of the Gondwanan (Late Carboniferous-Permian) sequence, locally known as the Pillahuincó Group. The underlying units of the Group show an integrated depositional history which can be explained in terms of glaciomarine sedimentation (Sauce Grande Formation) and postglacial transgression (Piedra Azul and Bonete Formations). This succession also has a rather uniform quartz-rich, sand-sized composition indicative of a cratonic provenance from the Tandilia Massif to the northeast. Early to Late Permian deformation folded and thrusted the southwestern basin margin (Sierras Australes) and triggered the deposition of a 1,500 m — thick, synorogenic prograding wedge, the Tunas Formation, in the adjacent foreland basin (Sauce Grande or Claromecó Basin). Sandstone detrital modes for the Tunas deposits show moderate to low contents of quartz and abundant lithics, mostly of volcanic and metasedimentary origin. Paleocurrents are consistently from the SW. Tuffs interbedded with sandstones in the upper half of Tunas Formation (Early — early Late? Permian) are interpreted as being derived from volcanic glass-rich tuffs settled in a body of water. Extensive rhyolitic ignimbrites and consanguineous airborne tuffaceous material erupted in the northern Patagonian region during that period. The age constraints and similarities in composition between these volcanics and the tuffaceous horizons present in the Sauce Grande, Parana and Karoo Basins suggest a genetic linkage between these two episodes. The intimate relationship between volcanic activity inboard of the paleo-Pacific margin, deformation in the adjacent orogenic belt and subsidence and sedimentation in the contiguous foreland basin constitutes a common motif in the Sauce Grande and Karoo Basins of southwestern Gondwana.

Object formation and subject formation: The innovation campus in the Netherlands

NARCIS (Netherlands)

Kooij, H.J.

2015-01-01

A central question within planning theory is how changes between the relations of ‘grand institutions’ such as state, market and education influence the formation of objects ‘on the ground’. Drawing upon Foucault’s work, this article contributes to the understanding of these relations and argues

Lower Miocene stratigraphy along the Panama Canal and its bearing on the Central American Peninsula.

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Michael Xavier Kirby

Full Text Available Before the formation of the Central American Isthmus, there was a Central American Peninsula. Here we show that southern Central America existed as a peninsula as early as 19 Ma, based on new lithostratigraphic, biostratigraphic and strontium chemostratigraphic analyses of the formations exposed along the Gaillard Cut of the Panama Canal. Land mammals found in the Miocene Cucaracha Formation have similar body sizes to conspecific taxa in North America, indicating that there existed a terrestrial connection with North America that allowed gene flow between populations during this time. How long did this peninsula last? The answer hinges on the outcome of a stratigraphic dispute: To wit, is the terrestrial Cucaracha Formation older or younger than the marine La Boca Formation? Previous stratigraphic studies of the Panama Canal Basin have suggested that the Cucaracha Formation lies stratigraphically between the shallow-marine Culebra Formation and the shallow-to-upper-bathyal La Boca Formation, the latter containing the Emperador Limestone. If the La Boca Formation is younger than the Cucaracha Formation, as many think, then the peninsula was short-lived (1-2 m.y., having been submerged in part by the transgression represented by the overlying La Boca Formation. On the other hand, our data support the view that the La Boca Formation is older than the Cucaracha Formation. Strontium dating shows that the La Boca Formation is older (23.07 to 20.62 Ma than both the Culebra (19.83-19.12 Ma and Cucaracha (Hemingfordian to Barstovian North American Land Mammal Ages; 19-14 Ma formations. The Emperador Limestone is also older (21.24-20.99 Ma than the Culebra and Cucaracha formations. What has been called the "La Boca Formation" (with the Emperador Limestone, is re-interpreted here as being the lower part of the Culebra Formation. Our new data sets demonstrate that the main axis of the volcanic arc in southern Central America more than likely existed as a

Lower Miocene stratigraphy along the Panama Canal and its bearing on the Central American Peninsula.

Science.gov (United States)

Kirby, Michael Xavier; Jones, Douglas S; MacFadden, Bruce J

2008-07-30

Before the formation of the Central American Isthmus, there was a Central American Peninsula. Here we show that southern Central America existed as a peninsula as early as 19 Ma, based on new lithostratigraphic, biostratigraphic and strontium chemostratigraphic analyses of the formations exposed along the Gaillard Cut of the Panama Canal. Land mammals found in the Miocene Cucaracha Formation have similar body sizes to conspecific taxa in North America, indicating that there existed a terrestrial connection with North America that allowed gene flow between populations during this time. How long did this peninsula last? The answer hinges on the outcome of a stratigraphic dispute: To wit, is the terrestrial Cucaracha Formation older or younger than the marine La Boca Formation? Previous stratigraphic studies of the Panama Canal Basin have suggested that the Cucaracha Formation lies stratigraphically between the shallow-marine Culebra Formation and the shallow-to-upper-bathyal La Boca Formation, the latter containing the Emperador Limestone. If the La Boca Formation is younger than the Cucaracha Formation, as many think, then the peninsula was short-lived (1-2 m.y.), having been submerged in part by the transgression represented by the overlying La Boca Formation. On the other hand, our data support the view that the La Boca Formation is older than the Cucaracha Formation. Strontium dating shows that the La Boca Formation is older (23.07 to 20.62 Ma) than both the Culebra (19.83-19.12 Ma) and Cucaracha (Hemingfordian to Barstovian North American Land Mammal Ages; 19-14 Ma) formations. The Emperador Limestone is also older (21.24-20.99 Ma) than the Culebra and Cucaracha formations. What has been called the "La Boca Formation" (with the Emperador Limestone), is re-interpreted here as being the lower part of the Culebra Formation. Our new data sets demonstrate that the main axis of the volcanic arc in southern Central America more than likely existed as a peninsula

Central Oregon 6 arc-second DEM

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The 6-second Central Coastal Oregon Elevation Grid provides bathymetric data in ASCII raster format of 6-second resolution in geographic coordinates. This grid is...

Cyclic platform dolomites and platform-to-basin transition of Jefferson Formation (Frasnian), southwest Montana and east-central Idaho

Energy Technology Data Exchange (ETDEWEB)

Dorobek, S.L.

1987-08-01

The Jefferson Formation (Frasnian) in southwestern Montana consists of cyclic sequences of shallow marine platformal dolomites that grade westward into slope/basinal facies in east-central Idaho. Regional sedimentologic characteristics of slope facies in Idaho indicate that the Jefferson platform resembled a distally steepened ramp. Slope facies consist of slope laminites with local small scale slumps and slope breccias. Shallow water platform-derived clasts are lacking in the slope breccias. Individual shallowing upward platform cycles are 25 m to < 1 m thick and consists of, in descending order: local solution-collapse breccia caps; cryptalgal dolomudstone; rare ooid dolograinstone; thin-bedded Amphipora dolowackestone; coarsely crystalline dolostones with abundant lenticular to domal stromatoporoids; and basal thin-bedded, fine-grained, shale dolostones with closely spaced hard-grounds that grade upward into burrow-homogenized, irregularly bedded dolostones.

Thoughts about Central Andean Formative Languages and Societies

OpenAIRE

Kaulicke, Peter

2012-01-01

This paper deals with the general problem of the Formative Period and presents a proposal for subdivision based upon characterizations of material cultures and their distributions as interaction spheres and traditions. These reflect significant changes that may be related to changes in the mechanisms of language dispersal. It hypothesizes that a pre-protomochica was spoken in northern Perú; that multilingualism prevailed at the site of Chavín site; and that different languages existed in the ...

Epigenetic Regulation of Memory Formation and Maintenance

Science.gov (United States)

Zovkic, Iva B.; Guzman-Karlsson, Mikael C.; Sweatt, J. David

2013-01-01

Understanding the cellular and molecular mechanisms underlying the formation and maintenance of memories is a central goal of the neuroscience community. It is well regarded that an organism's ability to lastingly adapt its behavior in response to a transient environmental stimulus relies on the central nervous system's capability for structural…

Magnetization of three Nubia Sandstone formations from Central Western Desert of Egypt

Directory of Open Access Journals (Sweden)

H. El-Shayeb

2013-06-01

The first magnetic component obtained from the two older formations is considered primary, as the corresponding pole reflects the age when compared with the previously obtained Cretaceous poles for North Africa. On other hand, the second pole obtained from the Maghrabi formation (the younger is inconsistent with the Cretaceous pole positions for North Africa, but falls closer to the Eocene pole indicating that the rocks of this formation could have suffered remagnetization during the late Eocene time.

Asie centrale | Page 39 | CRDI - Centre de recherches pour le ...

International Development Research Centre (IDRC) Digital Library (Canada)

Asie centrale. Asie centrale. Read more about Climate Change, Innovation, and Information and Communication Technologies. Langue English. Read more about Programme de formation en actuariat Inde-Canada (Waterloo). Langue French. Read more about Actuarial Sciences Graduate Training Program ...

Sedimentary environments and stratigraphy of the carbonate-silicilastic deposits of the Shirgesht Formation: implications for eustasy and local tectonism in the Kalmard Block, Central Iran

OpenAIRE

reza Mousavi-Harami; aram bayetgoll; asadolah Mahboubi

2015-01-01

Introduction   Sedimentological and sequence stratigraphic analysis providing insight into the main relationships between sequence architecture and stacking pattern, syn/post-depositional tectonics, and eustatic sea-level fluctuations (Gawthorpe and Leeder 2000; Zecchin et al. 2003, 2004; Carpentier et al. 2007). Relative variations in sea level are due to tectonic activity and eustasy. The Shirgesht Formation in the Kalmard Block of Central Iran provides a useful case study for to determine ...

The three phases of galaxy formation

Science.gov (United States)

Clauwens, Bart; Schaye, Joop; Franx, Marijn; Bower, Richard G.

2018-05-01

We investigate the origin of the Hubble sequence by analysing the evolution of the kinematic morphologies of central galaxies in the EAGLE cosmological simulation. By separating each galaxy into disc and spheroidal stellar components and tracing their evolution along the merger tree, we find that the morphology of galaxies follows a common evolutionary trend. We distinguish three phases of galaxy formation. These phases are determined primarily by mass, rather than redshift. For M* ≲ 109.5M⊙ galaxies grow in a disorganised way, resulting in a morphology that is dominated by random stellar motions. This phase is dominated by in-situ star formation, partly triggered by mergers. In the mass range 109.5M⊙ ≲ M* ≲ 1010.5M⊙ galaxies evolve towards a disc-dominated morphology, driven by in-situ star formation. The central spheroid (i.e. the bulge) at z = 0 consists mostly of stars that formed in-situ, yet the formation of the bulge is to a large degree associated with mergers. Finally, at M* ≳ 1010.5M⊙ growth through in-situ star formation slows down considerably and galaxies transform towards a more spheroidal morphology. This transformation is driven more by the buildup of spheroids than by the destruction of discs. Spheroid formation in these galaxies happens mostly by accretion at large radii of stars formed ex-situ (i.e. the halo rather than the bulge).

Stratigraphy, age, and depositional setting of the Miocene Barstow Formation at Harvard Hill, central Mojave Desert, California

Science.gov (United States)

Leslie, Shannon R.; Miller, David M.; Wooden, Joseph L.; Vazquez, Jorge A.

2010-01-01

New detailed geologic mapping and geochronology of the Barstow Formation at Harvard Hill, 30 km east of Barstow, CA, help to constrain Miocene paleogeography and tectonics of the central Mojave Desert. A northern strand of the Quaternary ENE-striking, sinistral Manix fault divides the Barstow Formation at Harvard Hill into two distinct lithologic assemblages. Strata north of the fault consist of: a green rhyolitic tuff, informally named the Shamrock tuff; lacustrine sandstone; partially silicified thin-bedded to massive limestone; and alluvial sandstone to pebble conglomerate. Strata south of the fault consist of: lacustrine siltstone and sandstone; a rhyolitic tuff dated at 19.1 Ma (U-Pb); rock-avalanche breccia deposits; partially silicified well-bedded to massive limestone; and alluvial sandstone and conglomerate. Our U-Pb zircon dating of the Shamrock tuff by SHRIMP-RG yields a peak probability age of 18.7 ± 0.1 Ma. Distinctive outcrop characteristics, mineralogy, remanent magnetization, and zircon geochemistry (Th/U) suggest that the Shamrock tuff represents a lacustrine facies of the regionally extensive Peach Spring Tuff (PST). Here we compare zircon age and geochemical analyses from the Shamrock tuff with those of the PST at Stoddard Wash and provide new insight into the age of zircon crystallization in the PST rhyolite. Results of our field studies show that Miocene strata at Harvard Hill mostly accumulated in a lacustrine environment, although depositional environments varied from a relatively deep lake to a very shallow lake or even onshore setting. Rock-avalanche breccias and alluvial deposits near the base of the exposed section indicate proximity to a steep basin margin and detrital studies suggest a southern source for coarse-grained deposits; therefore, we may infer a southern basin-margin setting at Harvard Hill during the early Miocene. Our geochronology demonstrates that deposition of the Barstow Formation at Harvard Hill extended from before

The Formation of New Monetary Policies: Decisions of Central Banks on the Great Recession

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Ana Esther Castro

2014-05-01

Full Text Available The effect that the Great Recession had on monetary policies has led to the profound reorientation of central banks’ actions from 2007 to 2013. The purpose of this work is to analyze the monetary policies applied by the main central banks, mainly the European Central Bank, the Federal Reserve System of USA and the Bank of Japan, in order to raise thoughts on the guidelines that central banks should follow in the future. In the first section the bases of monetary policy before the crisis are described; in the second we explain the change in the orientation of the role of central banks during the crisis; and finally, we synthesize the bases on which the economic debate is taking place on the orientation of future monetary policies. We conclude that, in so far as the inoperativeness of transmission mechanisms still persists, monetary policies will remain in a process of change.

Land degradation of Taleghan drainage basin, Iran from saline and alkaline marly formations

International Nuclear Information System (INIS)

Zakikhani, K.; Feiznia, S.; Hosseini, S. H.

2009-01-01

In Iran fine-grained, saline, alkaline and erodible Tertiary marly formations are exposed in many geological zones and play important role in the formation of present landforms. They also play important role in degradation of water resources and soils as diffuse sources, they are the main sources of suspension loads of many rivers and are endless sources of sediments for sand dunes. These marly formations are present in Zagros, Central Iran, Alborz and Kopeh Dagh geological Zones and consists of different geological formations such as Gachsaran, Mishan and Razak Formations ( in Zagros), Lower Red and Upper Red Formations ( in Central Iran) and Neogene Red Beds (in Albords and Kopeh Dagh). (Author)

Land degradation of Taleghan drainage basin, Iran from saline and alkaline marly formations

Energy Technology Data Exchange (ETDEWEB)

Zakikhani, K.; Feiznia, S.; Hosseini, S. H.

2009-07-01

In Iran fine-grained, saline, alkaline and erodible Tertiary marly formations are exposed in many geological zones and play important role in the formation of present landforms. They also play important role in degradation of water resources and soils as diffuse sources, they are the main sources of suspension loads of many rivers and are endless sources of sediments for sand dunes. These marly formations are present in Zagros, Central Iran, Alborz and Kopeh Dagh geological Zones and consists of different geological formations such as Gachsaran, Mishan and Razak Formations ( in Zagros), Lower Red and Upper Red Formations ( in Central Iran) and Neogene Red Beds (in Albords and Kopeh Dagh). (Author)

Coexistence facilitates interspecific biofilm formation in complex microbial communities

DEFF Research Database (Denmark)

Madsen, Jonas Stenløkke; Røder, Henriette Lyng; Russel, Jakob

2016-01-01

Social interactions in which bacteria respond to one another by modifying their phenotype are central determinants of microbial communities. It is known that interspecific interactions influence the biofilm phenotype of bacteria; a phenotype that is central to the fitness of bacteria. However......, the underlying role of fundamental ecological factors, specifically coexistence and phylogenetic history, in biofilm formation remains unclear. This study examines how social interactions affect biofilm formation in multi-species co-cultures from five diverse environments. We found prevalence of increased...

Central vasopressin V1a receptor activation is independently necessary for both partner preference formation and expression in socially monogamous male prairie voles.

Science.gov (United States)

Donaldson, Zoe R; Spiegel, Lauren; Young, Larry J

2010-02-01

The neuropeptide arginine vasopressin (AVP) modulates a variety of species-specific social behaviors. In socially monogamous male prairie voles, AVP acts centrally via vasopressin V1a receptor (V1aR) to facilitate mating induced partner preferences. The display of a partner preference requires at least 2 temporally distinct processes: social bond formation as well as its recall, or expression. Studies to date have not determined in which of these processes V1aR acts to promote partner preferences. Here, male prairie voles were administered intracerebroventricularly a V1aR antagonist (AVPA) at different time points to investigate the role of V1aR in social bond formation and expression. Animals receiving AVPA prior to cohabitation with mating or immediately prior to partner preference testing failed to display a partner preference, while animals receiving AVPA immediately after cohabitation with mating and control animals receiving vehicle at all 3 time points displayed partner preferences. These results suggest that V1aR signaling is necessary for both the formation and expression of partner preferences and that these processes are dissociable. (c) 2009 APA, all rights reserved.

Black-hole-regulated star formation in massive galaxies

Science.gov (United States)

Martín-Navarro, Ignacio; Brodie, Jean P.; Romanowsky, Aaron J.; Ruiz-Lara, Tomás; van de Ven, Glenn

2018-01-01

Supermassive black holes, with masses more than a million times that of the Sun, seem to inhabit the centres of all massive galaxies. Cosmologically motivated theories of galaxy formation require feedback from these supermassive black holes to regulate star formation. In the absence of such feedback, state-of-the-art numerical simulations fail to reproduce the number density and properties of massive galaxies in the local Universe. There is, however, no observational evidence of this strongly coupled coevolution between supermassive black holes and star formation, impeding our understanding of baryonic processes within galaxies. Here we report that the star formation histories of nearby massive galaxies, as measured from their integrated optical spectra, depend on the mass of the central supermassive black hole. Our results indicate that the black-hole mass scales with the gas cooling rate in the early Universe. The subsequent quenching of star formation takes place earlier and more efficiently in galaxies that host higher-mass central black holes. The observed relation between black-hole mass and star formation efficiency applies to all generations of stars formed throughout the life of a galaxy, revealing a continuous interplay between black-hole activity and baryon cooling.

Black-hole-regulated star formation in massive galaxies.

Science.gov (United States)

Martín-Navarro, Ignacio; Brodie, Jean P; Romanowsky, Aaron J; Ruiz-Lara, Tomás; van de Ven, Glenn

2018-01-18

Supermassive black holes, with masses more than a million times that of the Sun, seem to inhabit the centres of all massive galaxies. Cosmologically motivated theories of galaxy formation require feedback from these supermassive black holes to regulate star formation. In the absence of such feedback, state-of-the-art numerical simulations fail to reproduce the number density and properties of massive galaxies in the local Universe. There is, however, no observational evidence of this strongly coupled coevolution between supermassive black holes and star formation, impeding our understanding of baryonic processes within galaxies. Here we report that the star formation histories of nearby massive galaxies, as measured from their integrated optical spectra, depend on the mass of the central supermassive black hole. Our results indicate that the black-hole mass scales with the gas cooling rate in the early Universe. The subsequent quenching of star formation takes place earlier and more efficiently in galaxies that host higher-mass central black holes. The observed relation between black-hole mass and star formation efficiency applies to all generations of stars formed throughout the life of a galaxy, revealing a continuous interplay between black-hole activity and baryon cooling.

The Technical Training Programme for Nuclear Power Station Personnel; Programme de formation technique du personnel des centrales nucleaires; Programma tekhnicheskoj podgotovki personala yadernoj ehlektrostantsii; El programa de formacion tecnica del personal de una central nucleoelectrica

Energy Technology Data Exchange (ETDEWEB)

Howey, G. R. [Hydro-Electric Power Commission of Ontario, Toronto, Ontario (Canada)

1963-10-15

.), responsible for maintenance of all mechanical equipment; and (5) Service maintainers: responsible for a wide variety of less skilled tasks requiring lower qualifications. In addition to these general categories a few specialists are required, such as chemists and radiation protection officers. Organization of the NPD staff and training for future nuclear-power needs will be discussed. (author) [French] La centrale nucleaire de demonstration canadienne (NPD), creee par un organisme federal, l'Atomic Energy of Canada Limited, est exploitee par une compagnie provinciale de distribution d'electricite, la Hydro-Electric Power Commission of Ontario, qui pourvoit aussi aux besoins en personnel. Le recrutement et la formation du personnel de la centrale ont ete difficiles du fait que, recemment encore, la plupart des besoins en electricite de l'Ontario pouvaient etre satisfaits par les abondantes ressources hydro-electriques de cette province. La multiplication des centrales thermiques, depuis 1950, a cree une enorme demande de personnel. Pour faire face a cette situation, on a organise la formation de personnel pour les centrales nucleaires de la maniere suivante: a) un groupe initial d'ingenieurs a ete selectionne parmi des specialistes ayant une vaste experience des travaux dans le domaine nucleaire de l 'exploitation des centrales thermiques et de la production d'electricite; b) on a selectionne un autre groupe d'operateurs et d'agents des services d'entretien hautement qualifies; c) ces groupes ont recu une formation systematique comprenant l'exploitation de centrales nucleaires et de centrales thermiques a charbon, un enseignement theorique et pratique et des instructions donnees par les specialistes qui ont concu les plans de NPD ; d) un centre de formation nucleaire a ete cree et charge de la selection et de la formation du personnel supplementaire ainsi que de l 'organisation des examens officiels; il doit s'assurer, d'une maniere generale, de la competence du personnel

Ordovician and Silurian Phi Kappa and Trail Creek formations, Pioneer Mountains, central Idaho; stratigraphic and structural revisions, and new data on graptolite faunas

Science.gov (United States)

Dover, James H.; Berry, William B.N.; Ross, Reuben James

1980-01-01

clastic rocks reported in previously measured sections of the Phi Kappa, as well as the sequence along Phi Kappa Creek from which the name originates, are excluded from the Phi Kappa as revised and are reassigned to two structural plates of Mississippian Copper Basin Formation; other strata now excluded from the formation are reassigned to the Trail Creek Formation and to an unnamed Silurian and Devonian unit. As redefined, the Phi Kappa Formation is only about 240 m thick, compared with the 3,860 m originally estimated, and it occupies only about 25 percent of the outcrop area previously mapped in 1930 by H. G. Westgate and C. P. Ross. Despite this drastic reduction in thickness and the exclusion of the rocks along Phi Kappa Creek, the name Phi Kappa is retained because of widely accepted prior usage to denote the Ordovician graptolitic shale facies of central Idaho, and because the Phi Kappa Formation as revised is present in thrust slices on Phi Kappa Mountain, at the head of Phi Kappa Creek. The lithic and faunal consistency of this unit throughout the area precludes the necessity for major facies telescoping along individual faults within the outcrop belt. However, tens of kilometers of tectonic shortening seems required to juxtapose the imbricated Phi Kappa shale facies with the Middle Ordovician part of the carbonate and quartzite shale sequence of east central Idaho. The shelf rocks are exposed in the Wildhorse structural window of the northeastern Pioneer Mountains, and attain a thickness of at least 1,500 m throughout the region north and east of the Pioneer Mountains. The Phi Kappa is in direct thrust contact on intensely deformed medium- to high-grade metamorphic equivalents of the same shelf sequence in the Pioneer window at the south end of the Phi Kappa-Trail Creek outcrop belt. Along East Pass, Big Lake, and Pine Creeks, north of the Pioneer Mountains, some rocks previously mapped as Ramshorn Slate are lithologically and faunally equivalent to the P

THALAMID SPONGES FROM THE UPPER TRIASSIC (NORIAN-RHAETIAN NAYBAND FORMATION NEAR WALI-ABAD, SE ABADEH, CENTRAL IRAN(CONTRIBUTION TO TRIASSIC PALEONTOLOGY OF IRAN 4

Directory of Open Access Journals (Sweden)

BABA SENOWBARI-DARYAN

1999-03-01

Full Text Available An association of thalamid sponges including Amblysiphonella, Nevadathalamia, Stylothalamia, and Neoguadalupia, with the hexactinellid Casearia is described from the Upper Triassic (Norian-Rhaetian Nayband Formation of Hambast-Mts. near the small town of Wali-Abad (Abadeh region, central Iran. These Norian-Rhaetian (Neoguadalupia, Amblysiphonella, Nevadathalamia and Liassic (Stylothalamia columnaris Le Maitre thalamid sponge assemblages are exceptional associations, not previously reported from Iran nor from other localities in the world. The microfacies and organism associations in the sponge-bearing carbonates is discussed. Differences of macro- and microfaunal composition, as well as flora, support the recognition of Kristan-Tollmann et al. to classify the Nayband Formation in the Abadeh region as of a distinct unit, termed the "Wali-Abad-Faziesregion". Following thalamid sponge species are described as new: Nevadathalamia waliabadensis n. sp. and Stylothalamia hambastensis n. sp. 

Formation and preservation of greigite (Fe3S4) in a thick sediment layer from the central South Yellow Sea

Science.gov (United States)

Liu, Jianxing; Mei, Xi; Shi, Xuefa; Liu, Qingsong; Liu, Yanguang; Ge, Shulan

2018-04-01

Sediments from continental shelves are sensitive to changes in both oceanic and terrestrial conditions, and, therefore, magnetic minerals in such sediments are affected strongly by depositional and diagenetic processes. Here, we investigated systematically an N-S transect of three sediment cores from the central South Yellow Sea (SYS) muddy area. Magnetic data indicate the presence of a horizontally distributed thick greigite-bearing layer. From an age model based on published magnetostratigraphy, accelerator mass spectrometry 14C dating ages, sedimentary characteristics and foraminiferal analysis, this layer was deposited within marine isotope stages (MIS) 17-13, following an enhanced sulphidic period over MIS 21-19 when the YS Warm Current and the associated YS Cold Water Mass were strong and where underlying sediments have higher total organic carbon, total sulphur and trace element molybdenum contents. Trace element cadmium enrichment in the greigite-bearing layers is documented for the first time, which indicates that weakly sulphidic (i.e. with trace levels of free H2S) conditions existed before greigite formed in a sulphidic environment during early diagenesis. It also indicates that subsequent conditions free of oxygen and H2S after greigite formation are more favourable for its preservation. We propose that organic matter supply was controlled over an extended period by moderate primary productivity. The combined effects of palaeoclimate and local tectonic subsidence were crucial for the formation and preservation of the identified greigite. In brief, our study improves understanding of the formation and preservation mechanisms of greigite in continental shelf sediments and reveals mid-Pleistocene palaeoenvironmental changes in the SYS.

Ten-a affects the fusion of central complex primordia in Drosophila.

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Xuebo Cheng

Full Text Available The central complex of Drosophila melanogaster plays important functions in various behaviors, such as visual and olfactory memory, visual orientation, sleep, and movement control. However little is known about the genes regulating the development of the central complex. Here we report that a mutant gene affecting central complex morphology, cbd (central brain defect, was mapped to ten-a, a type II trans-membrane protein coding gene. Down-regulation of ten-a in pan-neural cells contributed to abnormal morphology of central complex. Over-expression of ten-a by C767-Gal4 was able to partially restore the abnormal central complex morphology in the cbd mutant. Tracking the development of FB primordia revealed that C767-Gal4 labeled interhemispheric junction that separated fan-shaped body precursors at larval stage withdrew to allow the fusion of the precursors. While the C767-Gal4 labeled structure did not withdraw properly and detached from FB primordia, the two fan-shaped body precursors failed to fuse in the cbd mutant. We propose that the withdrawal of C767-Gal4 labeled structure is related to the formation of the fan-shaped body. Our result revealed the function of ten-a in central brain development, and possible cellular mechanism underlying Drosophila fan-shaped body formation.

Supermassive Black Holes as the Regulators of Star Formation in Central Galaxies

Energy Technology Data Exchange (ETDEWEB)

Terrazas, Bryan A.; Bell, Eric F. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Woo, Joanna; Henriques, Bruno M. B. [Department of Physics, Institute for Astronomy, ETH Zurich, 8093 Zurich (Switzerland)

2017-08-01

We present the relationship between the black hole mass, stellar mass, and star formation rate (SFR) of a diverse group of 91 galaxies with dynamically measured black hole masses. For our sample of galaxies with a variety of morphologies and other galactic properties, we find that the specific SFR is a smoothly decreasing function of the ratio between black hole mass and stellar mass, or what we call the specific black hole mass. In order to explain this relation, we propose a physical framework where the gradual suppression of a galaxy’s star formation activity results from the adjustment to an increase in specific black hole mass, and accordingly, an increase in the amount of heating. From this framework, it follows that at least some galaxies with intermediate specific black hole masses are in a steady state of partial quiescence with intermediate specific SFRs, implying that both transitioning and steady-state galaxies live within this region that is known as the “green valley.” With respect to galaxy formation models, our results present an important diagnostic with which to test various prescriptions of black hole feedback and its effects on star formation activity.

Supermassive Black Holes as the Regulators of Star Formation in Central Galaxies

International Nuclear Information System (INIS)

Terrazas, Bryan A.; Bell, Eric F.; Woo, Joanna; Henriques, Bruno M. B.

2017-01-01

We present the relationship between the black hole mass, stellar mass, and star formation rate (SFR) of a diverse group of 91 galaxies with dynamically measured black hole masses. For our sample of galaxies with a variety of morphologies and other galactic properties, we find that the specific SFR is a smoothly decreasing function of the ratio between black hole mass and stellar mass, or what we call the specific black hole mass. In order to explain this relation, we propose a physical framework where the gradual suppression of a galaxy’s star formation activity results from the adjustment to an increase in specific black hole mass, and accordingly, an increase in the amount of heating. From this framework, it follows that at least some galaxies with intermediate specific black hole masses are in a steady state of partial quiescence with intermediate specific SFRs, implying that both transitioning and steady-state galaxies live within this region that is known as the “green valley.” With respect to galaxy formation models, our results present an important diagnostic with which to test various prescriptions of black hole feedback and its effects on star formation activity.

Central role of pyrophosphate in acellular cementum formation.

Directory of Open Access Journals (Sweden)

Brian L Foster

Full Text Available Inorganic pyrophosphate (PP(i is a physiologic inhibitor of hydroxyapatite mineral precipitation involved in regulating mineralized tissue development and pathologic calcification. Local levels of PP(i are controlled by antagonistic functions of factors that decrease PP(i and promote mineralization (tissue-nonspecific alkaline phosphatase, Alpl/TNAP, and those that increase local PP(i and restrict mineralization (progressive ankylosis protein, ANK; ectonucleotide pyrophosphatase phosphodiesterase-1, NPP1. The cementum enveloping the tooth root is essential for tooth function by providing attachment to the surrounding bone via the nonmineralized periodontal ligament. At present, the developmental regulation of cementum remains poorly understood, hampering efforts for regeneration. To elucidate the role of PP(i in cementum formation, we analyzed root development in knock-out ((-/- mice featuring PP(i dysregulation.Excess PP(i in the Alpl(-/- mouse inhibited cementum formation, causing root detachment consistent with premature tooth loss in the human condition hypophosphatasia, though cementoblast phenotype was unperturbed. Deficient PP(i in both Ank and Enpp1(-/- mice significantly increased cementum apposition and overall thickness more than 12-fold vs. controls, while dentin and cellular cementum were unaltered. Though PP(i regulators are widely expressed, cementoblasts selectively expressed greater ANK and NPP1 along the root surface, and dramatically increased ANK or NPP1 in models of reduced PP(i output, in compensatory fashion. In vitro mechanistic studies confirmed that under low PP(i mineralizing conditions, cementoblasts increased Ank (5-fold and Enpp1 (20-fold, while increasing PP(i inhibited mineralization and associated increases in Ank and Enpp1 mRNA.Results from these studies demonstrate a novel developmental regulation of acellular cementum, wherein cementoblasts tune cementogenesis by modulating local levels of PP(i, directing and

Complications of central venous stenosis due to permanent central venous catheters in children on hemodialysis.

Science.gov (United States)

Rinat, Choni; Ben-Shalom, Efrat; Becker-Cohen, Rachel; Feinstein, Sofia; Frishberg, Yaacov

2014-11-01

Central venous catheters are frequently used as access for hemodialysis (HD) in children. One of the known complications is central venous stenosis. Although this complication is not rare, it is often asymptomatic and therefore unacknowledged. Superior vena cava (SVC) stenosis is obviously suspected in the presence of upper body edema, but several other signs and symptoms are often unrecognized as being part of this syndrome. We describe four patients with various manifestations of central venous stenosis and SVC syndrome. These sometimes life- or organ-threatening conditions include obstructive sleep apnea, unresolving stridor, increased intracranial pressure, increased intraocular pressure, right-sided pleural effusion, protein-losing enteropathy and lymphadenopathy. The temporal relationship of these complications associated with the use of central venous catheters and documentation of venous stenosis, together with their resolution after alleviation of high venous pressure, points to a causal role. We suggest pathophysiological mechanisms for the formation of each of these complications. In patients with occlusion of the SVC, various unexpected clinical entities can be caused by high central venous pressure. As often the etiology is not obvious, a high index of suspicion is needed as in some cases prompt alleviation of the high pressure is mandatory.

Correlations and Areal Distribution of the Table Mountain Formation, Stanislaus Group; Central Sierra Nevada, California

Science.gov (United States)

Torrez, G.; Carlson, C. W.; Putirka, K. D.; Pluhar, C. J.; Sharma, R. K.

2011-12-01

Late Cenozoic evolution of the western Cordillera is a matter of ongoing debate in geologic studies. Volcanic deposits within, and adjacent to the Sierra Nevada have played a significant role in many of these debates. With local faulting coincident with eruption of members of the Stanislaus Group at ca. 38°N, the composition and correlation of these volcanics can greatly aid our understanding of Sierra Nevada tectonics. At the crest of the central Sierra Nevada, 23 trachyandesite lava flows of the Table Mountain Formation, dated at ~10 Ma, cap Sonora Peak. These 23 flows compose the thickest and most complete known stratigraphic section of the Table Mountain Formation in the region. Located ~12 km east of Sonora Peak are 16 flows of trachyandesite at Grouse Meadow. We have collected a detailed set of geochemical and paleomagnetic data for flows of these two sections at Sonora Peak and Grouse Meadows in an attempt to correlate volcanic, paleomagnetic and structural events related to uplift and extension in the Sierra Nevada and the Walker Lane. Correlation of individual flows is possible based on: stratigraphic order, temporal gaps in deposition as determined by paleomagnetic remanence direction and nonconformities, and flow geochemistry. These correlations allow us to infer source localities, flow directions, and temporal changes in flow routes. The large number of flows present at Grouse Meadow provides an additional data set from which to correlate various localities in the region to those units not represented at Sonora Peak. Several flows which occur in the upper portions of the Sonora Peak and Grouse Meadow stratigraphic sections do not correlate between these localities. The causes of stratigraphic discontinuity potentially represent: tectonic isolation across the Sierran Crest, topographic isolation by the emplacement of younger flows, or the combination of the two. Additional to the correlation of individual flows at these localities, this study shows a

Ammonoids from the Dalle des Iridet of the Mouydir and Ahnet (Central Sahara and the Formation d'Hassi Sguilma of the Saoura Valley (Late Tournaisian–Early Viséan; Algeria

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D. Korn

2010-02-01

Full Text Available Four ammonoid species are described from the Early Carboniferous (Mississippian Iridet Formation of the Ahnet and Mouydir (Central Sahara, Algeria; three of which are new: Eurites temertassetensis n. sp., Trimorphoceras teguentourense n. sp., and Trimorphoceras azzelmattiense n. sp. The species can be attributed to the North African Ammonellipsites-Merocanites Assemblage (Fascipericyclus-Ammonellipsites Genus Zone; Late Tournaisian to Early Viséan. Additionally, the two new species Ammonellipsites sguilmensis n. sp. and Muensteroceras beniabbesense n. sp. are described from the time equivalent Hassi Sguilma Formation of the Saoura Valley (north-western Algeria. doi:10.1002/mmng.200900012

Characterization of Most Promising Sequestration Formations in the Rocky Mountain Region (RMCCS)

Energy Technology Data Exchange (ETDEWEB)

McPherson, Brian; Matthews, Vince

2013-09-30

The primary objective of the “Characterization of Most Promising Carbon Capture and Sequestration Formations in the Central Rocky Mountain Region” project, or RMCCS project, is to characterize the storage potential of the most promising geologic sequestration formations within the southwestern U.S. and the Central Rocky Mountain region in particular. The approach included an analysis of geologic sequestration formations under the Craig Power Station in northwestern Colorado, and application or extrapolation of those local-scale results to the broader region. A ten-step protocol for geologic carbon storage site characterization was a primary outcome of this project.

SDSS-IV MaNGA: the spatial distribution of star formation and its dependence on mass, structure, and environment

Science.gov (United States)

Spindler, Ashley; Wake, David; Belfiore, Francesco; Bershady, Matthew; Bundy, Kevin; Drory, Niv; Masters, Karen; Thomas, Daniel; Westfall, Kyle; Wild, Vivienne

2018-05-01

We study the spatially resolved star formation of 1494 galaxies in the SDSS-IV MaNGA Survey. Star formation rates (SFRs) are calculated using a two-step process, using H α in star-forming regions and Dn4000 in regions identified as active galactic nucleus/low-ionization (nuclear) emission region [AGN/LI(N)ER] or lineless. The roles of secular and environmental quenching processes are investigated by studying the dependence of the radial profiles of specific star formation rate on stellar mass, galaxy structure, and environment. We report on the existence of `centrally suppressed' galaxies, which have suppressed Specific Star Formation Rate (SSFR) in their cores compared to their discs. The profiles of centrally suppressed and unsuppressed galaxies are distributed in a bimodal way. Galaxies with high stellar mass and core velocity dispersion are found to be much more likely to be centrally suppressed than low-mass galaxies, and we show that this is related to morphology and the presence of AGN/LI(N)ER like emission. Centrally suppressed galaxies also display lower star formation at all radii compared to unsuppressed galaxies. The profiles of central and satellite galaxies are also compared, and we find that satellite galaxies experience lower specific star formation rates at all radii than central galaxies. This uniform suppression could be a signal of the stripping of hot halo gas in the process known as strangulation. We find that satellites are not more likely to be suppressed in their cores than centrals, indicating that the core suppression is an entirely internal process. We find no correlation between the local environment density and the profiles of star formation rate surface density.

Superclusters and galaxy formation

International Nuclear Information System (INIS)

Einasto, J.; Joeveer, M.; Saar, E.

1979-01-01

The spatial distribution of Galaxies and Galaxy congestions in the southern galactic hemisphere is studied. The rich galaxy congestions, containing many elliptic Galaxies and radiogalaxies, are linked with each other by chains of scanty congestions with moderate content of elliptic Galaxies and radiogalaxies. The flat formation, linking the density pikes and the intermediate chains, can reasonably be called supercongestion. In the central region of supercongestions there is a thin layer of Galaxies consisting of only spiral Galaxies. The neighbouring supercongestions touch each other, while the intersupercongestion space contains no Galaxy congestions and almost no Galaxies. It is shown that such a structure was, apparently, formed before the formation of Galaxies

Memory, expectation formation and scheduling choices

NARCIS (Netherlands)

Koster, P.R.; Peer, S.; Dekker, T.

2015-01-01

Limited memory capacity, retrieval constraints and anchoring are central to expectation formation processes. We develop a model of adaptive expectations where individuals are able to store only a finite number of past experiences of a stochastic state variable. Retrieval of these experiences is

Galaxy formation and evolution

CERN Document Server

Mo, Houjun; White, Simon

2010-01-01

The rapidly expanding field of galaxy formation lies at the interface between astronomy, particle physics, and cosmology. Covering diverse topics from these disciplines, all of which are needed to understand how galaxies form and evolve, this book is ideal for researchers entering the field. Individual chapters explore the evolution of the Universe as a whole and its particle and radiation content; linear and nonlinear growth of cosmic structure; processes affecting the gaseous and dark matter components of galaxies and their stellar populations; the formation of spiral and elliptical galaxies; central supermassive black holes and the activity associated with them; galaxy interactions; and the intergalactic medium. Emphasizing both observational and theoretical aspects, this book provides a coherent introduction for astronomers, cosmologists, and astroparticle physicists to the broad range of science underlying the formation and evolution of galaxies.

Radionuclides at Descartes in the central highlands

Science.gov (United States)

Wrigley, R. C.

1973-01-01

Throium, uranium, potassium, aluminium-26, and sodium-22 were measured by nondestructive gamma ray spectrometry in six soil and two rock samples gathered by Apollo 16 in the lunar central highlands. The soil samples probably include both major geologic formations in the vicinity, the Cayley and Descartes Formations, although it is possible that the Descartes Formation is not represented. The rock samples have low concentrations of primordial radionuclides. The Al concentrations were lower than could be expected from the high abundance of alumina in the Apollo 16 soils reported earlier, but this could be due to lower concentrations of target elements in these soils, sampling depth variations, or regolithic mixing (exposure age variations).

Robust Decentralized Formation Flight Control

Directory of Open Access Journals (Sweden)

Zhao Weihua

2011-01-01

Full Text Available Motivated by the idea of multiplexed model predictive control (MMPC, this paper introduces a new framework for unmanned aerial vehicles (UAVs formation flight and coordination. Formulated using MMPC approach, the whole centralized formation flight system is considered as a linear periodic system with control inputs of each UAV subsystem as its periodic inputs. Divided into decentralized subsystems, the whole formation flight system is guaranteed stable if proper terminal cost and terminal constraints are added to each decentralized MPC formulation of the UAV subsystem. The decentralized robust MPC formulation for each UAV subsystem with bounded input disturbances and model uncertainties is also presented. Furthermore, an obstacle avoidance control scheme for any shape and size of obstacles, including the nonapriorily known ones, is integrated under the unified MPC framework. The results from simulations demonstrate that the proposed framework can successfully achieve robust collision-free formation flights.

Shallow Depth Study Using Gravity & Magnetics Data in Central Java - Yogyakarta

Science.gov (United States)

Fawzy Ismullah M, Muhammad; Altin Massinai, Muhammad; Maria

2018-03-01

Gravity and magnetics measurements carried out in Karangsambung - Bayat - Wonosari track, Central Java - Yogyakarta region as much as 34 points for subsurface identification. Modeling and interpretation using both data at 3 sections. Section A lies on Karangsambung area and reach to 1900 m. Section A showed formation of 0.000001 - 0.0014 nT and 2.00 - 2.80 g/cm3 like alluvium, basalt and tuff. Section B lies on Wates - Yogyakarta area and reach to 1700 m. Section B showed formation of (-0.01) - 0.02 nT and 2.40 - 3.00 g/cm3 like andesite intrusive and Merapi volcano sediments. Section C lies on Bayat - Wonosari area and reach to 2000 m. Section C showed formation of 0.00016 - 0.0005 nT and 2.30 - 3.14 g/cm3 like limestone, tuff and diorite intrusive. Based on modeling results from 2D structure inversion method can identify the formation of sediments from volcano activity on Karangsambung - Bayat - Wonosari track, Central Java - Yogyakarta region. The method of this study shows potential application for identify the formation of volcano activity from 2D structure.

Overview Chapter 5: Determinants of family formation and childbearing during the societal transition in Central and Eastern Europe

Directory of Open Access Journals (Sweden)

Tomas Frejka

2008-07-01

Full Text Available Societal conditions for early and high rates of childbearing were replaced by conditions generating late and low levels of fertility common in Western countries. Central among factors shaping the latter behaviour (job insecurity, unstable partnership relationships, expensive housing, and profound changes in norms, values and attitudes were the following: increasing proportions of young people were acquiring advanced education, a majority of women were gainfully employed, yet women were performing most household maintenance and childrearing duties. Two theories prevailed to explain what caused changes in family formation and fertility trends. One argues that the economic and social crises were the principal causes. The other considered the diffusion of western norms, values and attitudes as the prime factors of change. Neither reveals the root cause: the replacement of state socialist regimes with economic and political institutions of contemporary capitalism. The extraordinarily low period TFRs around 2000 were the result of low fertility of older women born around 1960 overlapping with low fertility of young women born during the 1970s.

Alteration of basaltic glasses from the Central Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Iyer, S.D.

Textural, mineralogical and compositional characteristics of basaltic glasses from the Central Indian Ocean show them to be altered to varying extents through their interaction with the seawater, resulting in the formation of palagonite. The major...

Multi-proxy constraints on sapropel formation during the late Pliocene of central Mediterranean (southwest Sicily)

Science.gov (United States)

Plancq, Julien; Grossi, Vincent; Pittet, Bernard; Huguet, Carme; Rosell-Melé, Antoni; Mattioli, Emanuela

2015-06-01

The late Pliocene (Piacenzian) in the Mediterranean region was punctuated by short-lived episodes of widespread deposition of organic-rich sedimentary layers known as sapropels. The causes of their formation remain a long-standing debate in the science community, and require disentangling the roles of climatic/oceanographic processes that triggered higher primary productivity or enhanced organic matter preservation. The lack of data, especially of sea temperatures at sufficient temporal resolution, is one of the main challenges to solve this debate. Here, we present new organic geochemistry and micropaleontological data from the late Pliocene at Punta Grande/Punta Piccola sections (southwest Sicily) that allow untangling the mechanisms that favored the formation of two sapropel series (noted S and A) in the central Mediterranean area during this period. Sea surface (SSTs) and subsurface temperatures were estimated using three distinct organic geochemical proxies namely the alkenone unsaturation index (UK‧37), the long-chain diol index (LDI) and the tetraether index (TEX86). Reconstructed SSTs are relatively stable throughout the late Pliocene and ∼4 °C higher than modern Mediterranean SSTs, which is consistent with the climatic conditions inferred for this period from paleoclimate modeling. An increase in SST is, however, recorded by UK‧37 and LDI proxies across each sapropel horizon, supporting that the two sapropel series S and A were formed during warmer climate conditions. The comparison of SST data with variations in accumulation rates of total organic carbon and lipid-biomarkers (alkenones, long-chain alkyl diols, archaeal and bacterial tetraethers), and with changes in calcareous nannofossil assemblages, indicates that the studied sapropels might have formed under different environmental conditions. The first series of sapropels (S), deposited between 3.1 and 2.8 Ma, is likely due to a better preservation of organic matter, induced by the development

The Suffix "-oso" in Central American Spanish.

Science.gov (United States)

Scavnicky, Gary Eugene A.

1982-01-01

Examines the lexical formative "-oso," which is added to nominal and verbal roots to form adjectives to denote possession of the quality contained in the primitive, in Central American Spanish. Concludes it is used with traditional Spanish denotations and has undergone various semantic shifts and is being applied to roots in a completely…

Development of the Central Dogma Concept Inventory (CDCI) Assessment Tool

OpenAIRE

Newman, Dina L.; Snyder, Christopher W.; Fisk, J. Nick; Wright, L. Kate

2016-01-01

Scientific teaching requires scientifically constructed, field-tested instruments to accurately evaluate student thinking and gauge teacher effectiveness. We have developed a 23-question, multiple select?format assessment of student understanding of the essential concepts of the central dogma of molecular biology that is appropriate for all levels of undergraduate biology. Questions for the Central Dogma Concept Inventory (CDCI) tool were developed and iteratively revised based on student lan...

Central oxytocin receptors mediate mating-induced partner preferences and enhance correlated activation across forebrain nuclei in male prairie voles

Science.gov (United States)

Johnson, Zachary V.; Walum, Hasse; Jamal, Yaseen A.; Xiao, Yao; Keebaugh, Alaine C.; Inoue, Kiyoshi; Young, Larry J.

2016-01-01

Oxytocin (OT) is a deeply conserved nonapeptide that acts both peripherally and centrally to modulate reproductive physiology and sociosexual behavior across divergent taxa, including humans. In vertebrates, the distribution of the oxytocin receptor (OTR) in the brain is variable within and across species, and OTR signaling is critical for a variety of species-typical social and reproductive behaviors, including affiliative and pair bonding behaviors in multiple socially monogamous lineages of fishes, birds, and mammals. Early work in prairie voles suggested that the endogenous OT system modulates mating-induced partner preference formation in females but not males; however, there is significant evidence that central OTRs may modulate pair bonding behavior in both sexes. In addition, it remains unclear how transient windows of central OTR signaling during sociosexual interaction modulate neural activity to produce enduring shifts in sociobehavioral phenotypes, including the formation of selective social bonds. Here we re-examine the role of the central OT system in partner preference formation in male prairie voles using a selective OTR antagonist delivered intracranially. We then use the same antagonist to examine how central OTRs modulate behavior and immediate early gene (Fos) expression, a metric of neuronal activation, in males during brief sociosexual interaction with a female. Our results suggest that, as in females, OTR signaling is critical for partner preference formation in males and enhances correlated activation across sensory and reward processing brain areas during sociosexual interaction. These results are consistent with the hypothesis that central OTR signaling facilitates social bond formation by coordinating activity across a pair bonding neural network. PMID:26643557

Star formation is boosted (and quenched) from the inside-out: radial star formation profiles from MaNGA

Science.gov (United States)

Ellison, Sara L.; Sánchez, Sebastian F.; Ibarra-Medel, Hector; Antonio, Braulio; Mendel, J. Trevor; Barrera-Ballesteros, Jorge

2018-02-01

The tight correlation between total galaxy stellar mass and star formation rate (SFR) has become known as the star-forming main sequence. Using ˜487 000 spaxels from galaxies observed as part of the Sloan Digital Sky Survey Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, we confirm previous results that a correlation also exists between the surface densities of star formation (ΣSFR) and stellar mass (Σ⋆) on kpc scales, representing a `resolved' main sequence. Using a new metric (ΔΣSFR), which measures the relative enhancement or deficit of star formation on a spaxel-by-spaxel basis relative to the resolved main sequence, we investigate the SFR profiles of 864 galaxies as a function of their position relative to the global star-forming main sequence (ΔSFR). For galaxies above the global main sequence (positive ΔSFR) ΔΣSFR is elevated throughout the galaxy, but the greatest enhancement in star formation occurs at small radii (<3 kpc, or 0.5Re). Moreover, galaxies that are at least a factor of 3 above the main sequence show diluted gas phase metallicities out to 2Re, indicative of metal-poor gas inflows accompanying the starbursts. For quiescent/passive galaxies that lie at least a factor of 10 below the star-forming main sequence, there is an analogous deficit of star formation throughout the galaxy with the lowest values of ΔΣSFR in the central 3 kpc. Our results are in qualitative agreement with the `compaction' scenario in which a central starburst leads to mass growth in the bulge and may ultimately precede galactic quenching from the inside-out.

Observations of environmental quenching in groups in the 11 Gyr since z = 2.5: Different quenching for central and satellite galaxies

International Nuclear Information System (INIS)

Tal, Tomer; Illingworth, Garth D.; Magee, Daniel; Dekel, Avishai; Oesch, Pascal; Van Dokkum, Pieter G.; Leja, Joel; Momcheva, Ivelina; Nelson, Erica J.; Muzzin, Adam; Franx, Marijn; Brammer, Gabriel B.; Marchesini, Danilo; Patel, Shannon G.; Quadri, Ryan F.; Rix, Hans-Walter; Skelton, Rosalind E.; Wake, David A.; Whitaker, Katherine E.

2014-01-01

We present direct observational evidence for star formation quenching in galaxy groups in the redshift range 0 < z < 2.5. We utilize a large sample of nearly 6000 groups, selected by fixed cumulative number density from three photometric catalogs, to follow the evolving quiescent fractions of central and satellite galaxies over roughly 11 Gyr. At z ∼ 0, central galaxies in our sample range in stellar mass from Milky Way/M31 analogs (M * /M ☉ = 6.5 × 10 10 ) to nearby massive ellipticals (M * /M ☉ = 1.5 × 10 11 ). Satellite galaxies in the same groups reach masses as low as twice that of the Large Magellanic Cloud (M * /M ☉ = 6.5 × 10 9 ). Using statistical background subtraction, we measure the average rest-frame colors of galaxies in our groups and calculate the evolving quiescent fractions of centrals and satellites over seven redshift bins. Our analysis shows clear evidence for star formation quenching in group halos, with a different quenching onset for centrals and their satellite galaxies. Using halo mass estimates for our central galaxies, we find that star formation shuts off in centrals when typical halo masses reach between 10 12 and 10 13 M ☉ , consistent with predictions from the halo quenching model. In contrast, satellite galaxies in the same groups most likely undergo quenching by environmental processes, whose onset is delayed with respect to their central galaxy. Although star formation is suppressed in all galaxies over time, the processes that govern quenching are different for centrals and satellites. While mass plays an important role in determining the star formation activity of central galaxies, quenching in satellite galaxies is dominated by the environment in which they reside.

Observations of environmental quenching in groups in the 11 Gyr since z = 2.5: Different quenching for central and satellite galaxies

Energy Technology Data Exchange (ETDEWEB)

Tal, Tomer; Illingworth, Garth D.; Magee, Daniel [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Dekel, Avishai [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Oesch, Pascal; Van Dokkum, Pieter G.; Leja, Joel; Momcheva, Ivelina; Nelson, Erica J. [Yale University Astronomy Department, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Muzzin, Adam; Franx, Marijn [Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands); Brammer, Gabriel B. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Marchesini, Danilo [Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States); Patel, Shannon G.; Quadri, Ryan F. [Carnegie Observatories, Pasadena, CA 91101 (United States); Rix, Hans-Walter [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Skelton, Rosalind E. [South African Astronomical Observatory, Observatory Road, Cape Town (South Africa); Wake, David A. [Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States); Whitaker, Katherine E., E-mail: tal@ucolick.org [Astrophysics Science Division, Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2014-07-10

We present direct observational evidence for star formation quenching in galaxy groups in the redshift range 0 < z < 2.5. We utilize a large sample of nearly 6000 groups, selected by fixed cumulative number density from three photometric catalogs, to follow the evolving quiescent fractions of central and satellite galaxies over roughly 11 Gyr. At z ∼ 0, central galaxies in our sample range in stellar mass from Milky Way/M31 analogs (M{sub *}/M{sub ☉} = 6.5 × 10{sup 10}) to nearby massive ellipticals (M{sub *}/M{sub ☉} = 1.5 × 10{sup 11}). Satellite galaxies in the same groups reach masses as low as twice that of the Large Magellanic Cloud (M{sub *}/M{sub ☉} = 6.5 × 10{sup 9}). Using statistical background subtraction, we measure the average rest-frame colors of galaxies in our groups and calculate the evolving quiescent fractions of centrals and satellites over seven redshift bins. Our analysis shows clear evidence for star formation quenching in group halos, with a different quenching onset for centrals and their satellite galaxies. Using halo mass estimates for our central galaxies, we find that star formation shuts off in centrals when typical halo masses reach between 10{sup 12} and 10{sup 13} M{sub ☉}, consistent with predictions from the halo quenching model. In contrast, satellite galaxies in the same groups most likely undergo quenching by environmental processes, whose onset is delayed with respect to their central galaxy. Although star formation is suppressed in all galaxies over time, the processes that govern quenching are different for centrals and satellites. While mass plays an important role in determining the star formation activity of central galaxies, quenching in satellite galaxies is dominated by the environment in which they reside.

Hydrogen-deficient Central Stars of Planetary Nebulae

Science.gov (United States)

Todt, H.; Kniazev, A. Y.; Gvaramadze, V. V.; Hamann, W.-R.; Pena, M.; Graefener, G.; Buckley, D.; Crause, L.; Crawford, S. M.; Gulbis, A. A. S.; Hettlage, C.; Hooper, E.; Husser, T.-O.; Kotze, P.; Loaring, N.; Nordsieck, K. H.; O'Donoghue, D.; Pickering, T.; Potter, S.; Romero-Colmenero, E.; Vaisanen, P.; Williams, T.; Wolf, M.

2015-06-01

A significant number of the central stars of planetary nebulae (CSPNe) are hydrogen-deficient and are considered as the progenitors of H-deficient white dwarfs. Almost all of these H-deficient CSPNe show a chemical composition of helium, carbon, and oxygen. Most of them exhibit Wolf-Rayet-like emission line spectra and are therefore classified as of spectral type [WC]. In the last years, CSPNe of other Wolf-Rayet spectral subtypes have been identified, namely PB 8 (spectral type [WN/WC]), IC 4663 and Abell 48 (spectral type [WN]). We performed spectral analyses for a number of Wolf-Rayet type central stars of different evolutionary stages with the help of our Potsdam Wolf-Rayet (PoWR) model code for expanding atmospheres to determine relevant stellar parameters. The results of our recent analyses will be presented in the context of stellar evolution and white dwarf formation. Especially the problems of a uniform evolutionary channel for [WC] stars as well as constraints to the formation of [WN] or [WN/WC] subtype stars will be addressed.

Central Venous Catheter-related Fungemia Caused by Rhodotorula glutinis.

Science.gov (United States)

Miglietta, Fabio; Letizia Faneschi, Maria; Braione, Adele; Palumbo, Claudio; Rizzo, Adriana; Lobreglio, Giambattista; Pizzolante, Maria

2015-01-01

Bloodstream infection due to Rhodotorula glutinis is extremely rare and mostly associated with underlying immunosuppression or cancer. Vascular access devices provide the necessary surfaces for biofilm formation and are currently responsible for a significant percentage of human infections. In this work, we describe a rare case of central venous catheter-related Rhodotorula glutinis fungemia in a female patient with acute myelogenous leukemia in remission. The timely removal of central venous catheter was an essential element for overcoming this CVC-related Rhodotorula fungemia.

GIVETIAN–FRASNIAN BOUNDARY CONODONTS FROM KERMAN PROVINCE, CENTRAL IRAN

OpenAIRE

GHOLAMALIAN, HOSSEIN; HAIRAPETIAN, VACHIK; BARFEHEI, NAHID; MANGELIAN, SOHEYLA; FARIDI, PARVANEH

2013-01-01

The Middle - Late Devonian boundary is investigated based on twenty-two conodont species and subspecies from three sections in the north and west of Kerman, southeastern central Iran. Upper Givetian - lower Frasnian carbonates of the basal part of the Bahram Formation transgressively overlie the sandstone beds of the top of (?) Early - Middle Devonian Padeha Formation. These massive skeletal limestones encompass the G-F boundary. The base of Frasnian is identified by the appearance of early f...

Insights into the dolomitization process and porosity modification in sucrosic dolostones, Avon Park Formation (Middle Eocene), East-Central Florida, U.S.A.

KAUST Repository

Maliva,, Robert G.

2011-03-01

The Avon Park Formation (middle Eocene) in central Florida, U.S.A., contains shallow-water carbonates that have been replaced by dolomite to varying degrees, ranging from partially replaced limestones, to highly porous sucrosic dolostones, to, less commonly, low-porosity dense dolostones. The relationships between dolomitization and porosity and permeability were studied focusing on three 305-m-long cores taken in the City of Daytona Beach. Stable-isotope data from pure dolostones (mean δ 18O = +3.91% V-PDB) indicate dolomite precipitation in Eocene penesaline pore waters, which would be expected to have been at or above saturation with respect to calcite. Nuclear magnetic log-derived porosity and permeability data indicate that dolomitization did not materially change total porosity values at the bed and formation scale, but did result in a general increase in pore size and an associated substantial increase in permeability compared to limestone precursors. Dolomitization differentially affects the porosity and permeability of carbonate strata on the scale of individual crystals, beds, and formations. At the crystal scale, dolomitization occurs in a volume-for-volume manner in which the space occupied by the former porous calcium carbonate is replaced by a solid dolomite crystal with an associated reduction in porosity. Dolomite crystal precipitation was principally responsible for calcite dissolution both at the actual site of dolomite crystal growth and in the adjoining rock mass. Carbonate is passively scavenged from the formation, which results in no significant porosity change at the formation scale. Moldic pores after allochems formed mainly in beds that experienced high degrees of dolomitization, which demonstrates the intimate association of the dolomitization process with carbonate dissolution. The model of force of crystallization-controlled replacement provides a plausible explanation for key observations concerning the dolomitization process in the

Insights into the dolomitization process and porosity modification in sucrosic dolostones, Avon Park Formation (Middle Eocene), East-Central Florida, U.S.A.

KAUST Repository

Maliva,, Robert G.; Budd, David A.; Clayton, Edward A.; Missimer, Thomas M.; Dickson, John Anthony D

2011-01-01

The Avon Park Formation (middle Eocene) in central Florida, U.S.A., contains shallow-water carbonates that have been replaced by dolomite to varying degrees, ranging from partially replaced limestones, to highly porous sucrosic dolostones, to, less commonly, low-porosity dense dolostones. The relationships between dolomitization and porosity and permeability were studied focusing on three 305-m-long cores taken in the City of Daytona Beach. Stable-isotope data from pure dolostones (mean δ 18O = +3.91% V-PDB) indicate dolomite precipitation in Eocene penesaline pore waters, which would be expected to have been at or above saturation with respect to calcite. Nuclear magnetic log-derived porosity and permeability data indicate that dolomitization did not materially change total porosity values at the bed and formation scale, but did result in a general increase in pore size and an associated substantial increase in permeability compared to limestone precursors. Dolomitization differentially affects the porosity and permeability of carbonate strata on the scale of individual crystals, beds, and formations. At the crystal scale, dolomitization occurs in a volume-for-volume manner in which the space occupied by the former porous calcium carbonate is replaced by a solid dolomite crystal with an associated reduction in porosity. Dolomite crystal precipitation was principally responsible for calcite dissolution both at the actual site of dolomite crystal growth and in the adjoining rock mass. Carbonate is passively scavenged from the formation, which results in no significant porosity change at the formation scale. Moldic pores after allochems formed mainly in beds that experienced high degrees of dolomitization, which demonstrates the intimate association of the dolomitization process with carbonate dissolution. The model of force of crystallization-controlled replacement provides a plausible explanation for key observations concerning the dolomitization process in the

Bioengineered Hydrogel to Inhibit Post-Traumatic Central Nervous System Scarring

Science.gov (United States)

2016-10-01

AWARD NUMBER: W81XWH-14-1-0586 TITLE: Bioengineered Hydrogel to Inhibit Post-Traumatic Central Nervous System Scarring PRINCIPAL...Hydrogel to Inhibit Post-Traumatic Central Nervous System Scarring 5a. CONTRACT NUMBER W81XWH-14-1-0586 5b. GRANT NUMBER W81XWH- 14-1-0586 5c...barriers that prevent the optimal delivery of biologics and cells to the injured nervous system . A significant problem is the formation of scar tissue

China’s foreign policy towards Central and Eastern Europe: The “16+1” format in the South–South cooperation perspective. Cases of the Czech Republic and Hungary

Directory of Open Access Journals (Sweden)

Bartosz Kowalski

2017-04-01

Full Text Available This article discusses the “16+1” format initiated in 2012 as a platform for economic, trade, and cultural cooperation between Central and Eastern Europe (CEE and China. As Chinese authorities claim, the “16+1” initiative is complementary to the “New Silk Road” strategy, being a pragmatic formula without political goals, whose main rationale is to bring mutual benefits to all of its participants (win–win. However, despite the Chinese narratives concerning cooperation with the CEE countries as an economic bridgehead of the “One Road, One Belt” (OBOR initiative, some signs of the political dimension of the project can be noticed. Since at least the 1950s, active participation and promotion of the South–South cooperation has become an important component of China’s foreign relations. Although for Chinese policy makers Sino–South relations have been traditionally defined within the frame of, mostly postcolonial, developing countries of Southeast Asia, Central Asia, Africa, and Latin America, this article tries to examine the “South–South” pattern of China’s diplomacy towards Central and Eastern European states with a focus on the Czech Republic and Hungary.

Possible Outflow Formation in the Central Engine of GRBs Tong Liu ...

Indian Academy of Sciences (India)

be geometrically thick when advection becomes dominant. In this paper, we dis- cuss the enhanced neutrino annihilation luminosity and the possible formation of the accretion flow. 2. Results. Figure 1(a) shows that there exists a narrow empty funnel along the rotation axis. Thus the volume above the disk shrinks and the ...

Clay mineral formation and fabric development in the DFDP-1B borehole, central Alpine Fault, New Zealand

International Nuclear Information System (INIS)

Schleicher, A.M.; Sutherland, R.; Townend, J.; Toy, V.G.; Van der Pluijm, B.A.

2015-01-01

Clay minerals are increasingly recognised as important controls on the state and mechanical behaviour of fault systems in the upper crust. Samples retrieved by shallow drilling from two principal slip zones within the central Alpine Fault, South Island, New Zealand, offer an excellent opportunity to investigate clay formation and fluid-rock interaction in an active fault zone. Two shallow boreholes, DFDP-1A (100.6 m deep) and DFDP-1B (151.4 m) were drilled in Phase 1 of the Deep Fault Drilling Project (DFDP-1) in 2011. We provide a mineralogical and textural analysis of clays in fault gouge extracted from the Alpine Fault. Newly formed smectitic clays are observed solely in the narrow zones of fault gouge in drill core, indicating that localised mineral reactions are restricted to the fault zone. The weak preferred orientation of the clay minerals in the fault gouge indicates minimal strain-driven modification of rock fabrics. While limited in extent, our results support observations from surface outcrops and faults systems elsewhere regarding the key role of clays in fault zones and emphasise the need for future, deeper drilling into the Alpine Fault in order to understand correlative mineralogies and fabrics as a function of higher temperature and pressure conditions. (author).

Episodic crustal growth in the Bundelkhand craton of central India ...

Indian Academy of Sciences (India)

Hiredya Chauhan

2018-04-12

Apr 12, 2018 ... geochemical features indicate formation of the K-granites by anhydrous partial melting of the Paleo- ...... A metamorphic episode from white mica schist is reported ...... monian G 2013 Central/eastern Indian Bundelkhand and.

Network Configuration Analysis for Formation Flying Satellites

Science.gov (United States)

Knoblock, Eric J.; Wallett, Thomas M.; Konangi, Vijay K.; Bhasin, Kul B.

2001-01-01

The performance of two networks to support autonomous multi-spacecraft formation flying systems is presented. Both systems are comprised of a ten-satellite formation, with one of the satellites designated as the central or 'mother ship.' All data is routed through the mother ship to the terrestrial network. The first system uses a TCP/EP over ATM protocol architecture within the formation, and the second system uses the IEEE 802.11 protocol architecture within the formation. The simulations consist of file transfers using either the File Transfer Protocol (FTP) or the Simple Automatic File Exchange (SAFE) Protocol. The results compare the IP queuing delay, IP queue size and IP processing delay at the mother ship as well as end-to-end delay for both systems. In all cases, using IEEE 802.11 within the formation yields less delay. Also, the throughput exhibited by SAFE is better than FTP.

Central oxytocin receptors mediate mating-induced partner preferences and enhance correlated activation across forebrain nuclei in male prairie voles.

Science.gov (United States)

Johnson, Zachary V; Walum, Hasse; Jamal, Yaseen A; Xiao, Yao; Keebaugh, Alaine C; Inoue, Kiyoshi; Young, Larry J

2016-03-01

Oxytocin (OT) is a deeply conserved nonapeptide that acts both peripherally and centrally to modulate reproductive physiology and sociosexual behavior across divergent taxa, including humans. In vertebrates, the distribution of the oxytocin receptor (OTR) in the brain is variable within and across species, and OTR signaling is critical for a variety of species-typical social and reproductive behaviors, including affiliative and pair bonding behaviors in multiple socially monogamous lineages of fishes, birds, and mammals. Early work in prairie voles suggested that the endogenous OT system modulates mating-induced partner preference formation in females but not males; however, there is significant evidence that central OTRs may modulate pair bonding behavior in both sexes. In addition, it remains unclear how transient windows of central OTR signaling during sociosexual interaction modulate neural activity to produce enduring shifts in sociobehavioral phenotypes, including the formation of selective social bonds. Here we re-examine the role of the central OT system in partner preference formation in male prairie voles using a selective OTR antagonist delivered intracranially. We then use the same antagonist to examine how central OTRs modulate behavior and immediate early gene (Fos) expression, a metric of neuronal activation, in males during brief sociosexual interaction with a female. Our results suggest that, as in females, OTR signaling is critical for partner preference formation in males and enhances correlated activation across sensory and reward processing brain areas during sociosexual interaction. These results are consistent with the hypothesis that central OTR signaling facilitates social bond formation by coordinating activity across a pair bonding neural network. Copyright © 2015 Elsevier Inc. All rights reserved.

Seismic reflection surveys in central Palo Duro basin

International Nuclear Information System (INIS)

Acharya, H.; Buller, M.L.; Lewkowicz, J.; Murphy, P.

1983-01-01

Seismic reflection surveys have been conducted in the central Palo Duro basin to provide a basis for identifying localities suitable for the emplacement of an underground high level nuclear waste repository. The objectives of this effort were to determine the structure and stratigraphy in the central Palo Duro basin and evaluate the potential for hydrocarbon resources. Of primary interest is the Upper Permian salt section to a depth of about 3000 ft (914 m). Various tests were carried out along a 3 mi (5 km) segment to determine the most appropriate combination of vibrating source and recording parameters. Approximately 130 mi (209 km) of 24-fold CDP stacked data were acquired. The survey lines were tied to test wells in which velocity surveys were conducted. These data were supplemented by about 400 mi (644 km) of available proprietary CDP stacked data. Analysis of these data strongly suggests that central Palo Duro basin has been tectonically stable since Early Permian time. The maximum offset of the basement is about 600 ft (183 m). These basement faults do not appear to affect any strata above. The San Andres Formation and underlying formations can be traced continuously throughout the area surveyed. Available velocity data from various wells in the central Palo Duro basin show few anomalies, confirming the continuity of the reflecting horizons and the tectonic stability of the area. Hydrocarbon potential of the area is presently being evaluated. The preliminary results of this study are in agreement with the stratigraphic correlations among well logs in the Palo Duro basin

Petrographic Evidence of Microbial Mats in the Upper Cretaceous Fish-Bearing, Organic-Rich Limestone, Agua Nueva Formation, Central Mexico

Science.gov (United States)

Blanco, A.; Maurrasse, F. J.; Hernández-Ávila, J.; Ángeles-Trigueros, S. A.; García-Cabrera, M. E.

2013-05-01

We document petrographic evidence of microbial mats in the Upper Cretaceous Agua Nueva Formation in the area of Xilitla (San Luis Potosí, Central Mexico), located in the southern part of the Tampico-Misantla basin. The sequence consists predominantly of alternating decimeter-thick beds of fossiliferous dark laminated limestone (C-org > 1.0wt%), and light gray, bioturbated limestone (C-org Duque-Botero and Maurrasse, 2005; 2008). These structures are also analogous to microbial mats in present environments, and Devonian deposits (Kremer, 2006). In addition, the laminae at Xilitla include filamentous bacterial structures, as thin and segmented red elements. In some thin sections, filaments appear to be embedded within the crinkly laminae and shreds showing the same pattern of folding, suggestive of biomorphic elements that represent the main producers of the organic matter associated with the laminae. Thus, exceptional bacterial activity characterizes sedimentation during the accumulation of the Agua Nueva Formation. Oxygen-deficient conditions related to the microbial mats were an important element in the mass mortality and preservation of the fish assemblages. Absence of bioturbation, pervasive framboidal pyrite, and the high concentration of organic matter (TOC ranges from 1.2% to 8wt%) in the dark limestones are consistent with persistent recurring dysoxic/anoxic conditions, and the light-gray bioturbated limestones represent relatively well-oxygenated episodes. Planktonic foraminifera (Rotalipora cushmani) and Inoceramu labiatus indicate a time interval from the latest Cenomanian through the earliest Turonian, thus this long interval of severe oxygen deficiency is coeval with Oceanic Anoxic Event 2 (OAE-2). [Duque-Botero and Maurrasse. 2005. Jour. Iberian Geology (31), 85-98; 2008. Cret. Res., 29, 957-964; Kremer. 2006. Acta Palaeontologica Polonica (51, 1), 143-154

Structures formation through self-organized accretion on cosmic strings

International Nuclear Information System (INIS)

Murdzek, R.

2009-01-01

In this paper, we shall show that the formation of structures through accretion by a cosmic string is driven by a natural feed-back mechanism: a part of the energy radiated by accretions creates a pressure on the accretion disk itself. This phenomenon leads to a nonlinear evolution of the accretion process. Thus, the formation of structures results as a consequence of a self-organized growth of the accreting central object.

Retail Market Structure Development in Central Europe

Directory of Open Access Journals (Sweden)

Martin Machek

2012-12-01

Full Text Available This article is analyzing the trends and development in the retailing sector in Central Europe, namely in the Czech Republic, Hungary, Poland and Slovakia. These markets serve about 63 million inhabitants. The retail industry in Central Europe has changed dramatically in the last two decades, and has become a model for successful transformation of emerging markets. The retail market is highly concentrated and dominated by Western European retail chains. International retail chains are using all formats of modern distribution. This article is focusing on the development of hypermarkets, supermarkets and discount stores. Due to the international retail chains, Central European countries benefit from a dense network of modern shopping places; the intense competition of highly productive retailers contributes to the lower level of inflation rate because of the so-called Wal-Mart Effect. The constant pressure on prices influences the marketing strategies of both retailers and suppliers.

Simulation of CIFF (Centralized IFF) remote control displays

Science.gov (United States)

Tucker, D. L.; Leibowitz, L. M.

1986-06-01

This report presents the software simulation of the Remote-Control-Display (RCS) proposed to be used in the Centralized IFF (CIFF) system. A description of the simulation programs along with simulated menu formats are presented. A sample listing of the simulation programs and a brief description of the program operation are also included.

Post-translational modification of osteopontin: Effects on in vitro hydroxyapatite formation and growth

International Nuclear Information System (INIS)

Boskey, Adele L.; Christensen, Brian; Taleb, Hayat; Sørensen, Esben S.

2012-01-01

Highlights: ► Thrombin-cleaved fragments of milk-osteopontin effect hydroxyapatite formation differently. ► N- and C-terminal fragments promoted hydroxyapatite formation and growth. ► A central fragment inhibited hydroxyapatite formation and growth. ► Binding to collagen or hydroxyapatite seed crystals modified these effects. -- Abstract: The manuscript tests the hypothesis that posttranslational modification of the SIBLING family of proteins in general and osteopontin in particular modify the abilities of these proteins to regulate in vitro hydroxyapatite (HA) formation. Osteopontin has diverse effects on hydroxyapatite (HA) mineral crystallite formation and growth depending on the extent of phosphorylation. We hypothesized that different regions of full-length OPN would also have distinct effects on the mineralization process. Thrombin fragmentation of milk OPN (mOPN) was used to test this hypothesis. Three fragments were tested in a de novo HA formation assay; an N-terminal fragment (aa 1–147), a central fragment (aa 148–204) denoted SKK-fragment and a C-terminal fragment (aa 205–262). Compared to intact mOPN the C- and N-terminal fragments behaved comparably, promoting HA formation and growth, but the central SKK-fragment acted as a mineralization inhibitor. In a seeded growth experiment all fragments inhibited mineral proliferation, but the SKK-fragment was the most effective inhibitor. These effects, seen in HA-formation and seeded growth assays in a gelatin gel system and in a pH-stat experiment were lost when the protein or fragments were dephosphorylated. Effects of the fully phosphorylated protein and fragments were also altered in the presence of fibrillar collagen. The diverse effects can be explained in terms of the intrinsically disordered nature of OPN and its fragments which enable them to interact with their multiple partners.

Sedimentology and High Resolution Sequence Stratigraphy of the Middle Jurassic Dhruma Formation Carbonates Outcrops in the Central Saudi Arabia

Science.gov (United States)

Yousif, Ibrahim; Abdullatif, Osman; Makkawi, Mohammed; Abdulghani, Waleed

2017-04-01

This study investigates the microfacies and sequence stratigraphic frame work of the Middle Jurassic Dhruma Formation in outcrops in central Saudi Arabia. The study contributes to the efforts to understand and enhance local and regional stratigraphic relationship and correlation of the Jurassic carbonate sequences and their significance to reservoir description and prediction in the subsurcae. The study describes and characterizes the sedimentology, microfacies and the stratigraphy of Dhruma Formation from outcrop sections having a total thickness of 70 m. Detailed microfacies and high-resolution stratigraphical analysis were carried out to determine microfacies, cyclicity, sequences and staking pattern. The study revealed ten lithofacies namely: oolitic grainstone,bioclastic oolitic grainstone, oolitic grapestone, bioclastic grainstone,foraminiferal packstone, echinoderm packstone, peloidal packstone to grainstone,skeletal wackestone to packstone, mudstone, and marlstone.These lithofacies were grouped into five lithofacies associations that deposited on a carbonate ramp setting. The depositional environment ranging from low energy lagoonal setting to high-energy shoals and banks to low energy outer ramp setting. Five high-resolution composite sequences have been defined and each sequence is composed at the bottom of intercalated mudstone/wackestone that passing up into grainstone lithofacies.The composite sequences range in thickness from 7 to 15 m, while the parasequences range from 0.5 to 1.5 m. The composite sequences extend laterally for a distance of more than 350 m. The overall composite section shows a shallowing upward succession of the 4th to the 5th order high-resolution sequences.The dominant lithofacies are the grainy ones, which constitute 30%, 50% and 80% of the studied sections. Furthermore, the parasequences thickness and their bio-components are increasing towards the top. The muddy lithofacies intensively affected the vertical continuity of the

A Reinterpretation of the Baturetno Formation: Stratigraphic Study of the Baturetno Basin, Wonogiri, Central Java

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Purna Sulastya Putra

2015-09-01

Full Text Available DOI:10.17014/ijog.2.3.125-137This paper focuses on the Quaternary Baturetno Formation. An earlier research concluded that the black clay of the Baturetno Formation formed as a ‘palaeolake’ deposit. The ‘palaeolake’ was interpreted to form due to the shifting course of the Bengawan Solo Purba River in relation to Pliocene tectonic tilting in the southern Java. The stratigraphy of the Baturetno Formation was observed in the western part of the Baturetno Basin, and based on marker beds, the Baturetno Formation was classified into three units: (1 Gravel unit (GR in the upper part, (2 clay unit (CU in the middle part, and (3 sand-gravel unit (SG in the lower part. There are floating gravel fragments of andesite, claystone, coral, and limestone with diameters of up to 10 cm in the clay unit. The particle size of sediment reflects the environment, but the lake deposition occurs under very quiet conditions. The occurrence of these fragments within the clay cannot be explained if the clay was deposited within a lake environment. The occurrence of floating fragments in the black clay of Baturetno Formation can best be explained through mudflow process. The cohesive strength of the mudflow is responsible for the ability of large fragments to float within the mud matrix. In general, the Baturetno Formation is inferred to be an alluvial fan deposit. The presence of sand, gravel, and mud are characteristics of alluvial fan deposits.

Re-initiation of bottom water formation in the East Sea (Japan Sea) in a warming world.

Science.gov (United States)

Yoon, Seung-Tae; Chang, Kyung-Il; Nam, SungHyun; Rho, TaeKeun; Kang, Dong-Jin; Lee, Tongsup; Park, Kyung-Ae; Lobanov, Vyacheslav; Kaplunenko, Dmitry; Tishchenko, Pavel; Kim, Kyung-Ryul

2018-01-25

The East Sea (Japan Sea), a small marginal sea in the northwestern Pacific, is ventilated deeply down to the bottom and sensitive to changing surface conditions. Addressing the response of this marginal sea to the hydrological cycle and atmospheric forcing would be helpful for better understanding present and future environmental changes in oceans at the global and regional scales. Here, we present an analysis of observations revealing a slowdown of the long-term deepening in water boundaries associated with changes of water formation rate. Our results indicate that bottom (central) water formation has been enhanced (reduced) with more (less) oxygen supply to the bottom (central) layer since the 2000s. This paper presents a new projection that allows a three-layered deep structure, which retains bottom water, at least until 2040, contrasting previous results. This projection considers recent increase of slope convections mainly due to the salt supply via air-sea freshwater exchange and sea ice formation and decrease of open-ocean convections evidenced by reduced mixed layer depth in the northern East Sea, resulting in more bottom water and less central water formations. Such vigorous changes in water formation and ventilation provide certain implications on future climate changes.

Networks for Autonomous Formation Flying Satellite Systems

Science.gov (United States)

Knoblock, Eric J.; Konangi, Vijay K.; Wallett, Thomas M.; Bhasin, Kul B.

2001-01-01

The performance of three communications networks to support autonomous multi-spacecraft formation flying systems is presented. All systems are comprised of a ten-satellite formation arranged in a star topology, with one of the satellites designated as the central or "mother ship." All data is routed through the mother ship to the terrestrial network. The first system uses a TCP/lP over ATM protocol architecture within the formation the second system uses the IEEE 802.11 protocol architecture within the formation and the last system uses both of the previous architectures with a constellation of geosynchronous satellites serving as an intermediate point-of-contact between the formation and the terrestrial network. The simulations consist of file transfers using either the File Transfer Protocol (FTP) or the Simple Automatic File Exchange (SAFE) Protocol. The results compare the IF queuing delay, and IP processing delay at the mother ship as well as application-level round-trip time for both systems, In all cases, using IEEE 802.11 within the formation yields less delay. Also, the throughput exhibited by SAFE is better than FTP.

The paredon, Mexico, obsidian source and early formative exchange.

Science.gov (United States)

Charlton, T H; Grove, D C; Hopke, P K

1978-09-01

In 1975, archeological surface surveys of trade routes located again a pre-Hispanic obsidian source in central Mexico first reported in 1902. Initial trace element studies of the Paredón source through an analysis by neutron activation have been compared with similar studies of the obsidian found at Chalcatzingo 150 kilometers from the source. These comparisons indicate that obsidian from Paredón, rather than Otumba, was of primary importance during the Early Formative in central Mexico.

Early Middle Formative Occupation in the Central Maya Lowlands: Recent Evidence from Cahal Pech, Belize

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Jaime Awe

1990-11-01

Full Text Available After more than half a century of intensive archaeological research the early Middle Formative (or Middle Preclassic period (1000-600 B.C. continues to be one of the most enigmatic eras in the study of Lowland Maya prehistory. While several factors contribte to this situation, the primary cause for this obscurity lies in the fact that few sites have produced either contextual or stratigraphic evidence of occupation during this phase (Rice 1976; Andrews 1988. Concsequently, any new site with evidence of Middle Formative occupation can contribute substantially to our limited knowledge of this pioneering stage of the lowland Maya. This paper introduces one such site, Cahal Pech, where recent investigations have uncovered a stratigraphic sequence that tentatively spans the early Middle Formative to the Late Classic period. It provides a preliminary description, of the site's early Middle Formative configuration and briefly discusses its possible regional affiliation.

A Systematic Approach to Process Evaluation in the Central Oklahoma Turning Point (COTP) Partnership

Science.gov (United States)

Tolma, Eleni L.; Cheney, Marshall K.; Chrislip, David D.; Blankenship, Derek; Troup, Pam; Hann, Neil

2011-01-01

Formation is an important stage of partnership development. Purpose: To describe the systematic approach to process evaluation of a Turning Point initiative in central Oklahoma during the formation stage. The nine-month collaborative effort aimed to develop an action plan to promote health. Methods: A sound planning framework was used in the…

Formation and control of plasma potentials in TMX upgrade

Energy Technology Data Exchange (ETDEWEB)

Simonen, T.C.; Orzechowski, T.J.; Porkolab, M.; Stallard, B.W.

1981-05-06

The methods to be employed to form and control plasma potentials in the TMX Upgrade tandem mirror with thermal barriers are described. ECRH-generated mirror -confined electron plasmas are used to establish a negative potential region to isolate the end-plug and central-cell celectrons. This thermal isolation will allow a higher end-plug electron temperature and an increased central-cell confining potential. Improved axial central-cell ion confinement results since higher temperature central-cell ions can be confined. This paper describes: (1) calculations of the sensitivity of barrier formation to vacuum conditions and to the presence of impurities in the neutral beams, (2) calculations of microwave penetration and absorption used to design the ECRH system, and (3) techniques to limit electron runaway to high energies by localized microwave beams and by relativistic detuning.

Formation and control of plasma potentials in TMX upgrade

International Nuclear Information System (INIS)

Simonen, T.C.; Orzechowski, T.J.; Porkolab, M.; Stallard, B.W.

1981-01-01

The methods to be employed to form and control plasma potentials in the TMX Upgrade tandem mirror with thermal barriers are described. ECRH-generated mirror -confined electron plasmas are used to establish a negative potential region to isolate the end-plug and central-cell celectrons. This thermal isolation will allow a higher end-plug electron temperature and an increased central-cell confining potential. Improved axial central-cell ion confinement results since higher temperature central-cell ions can be confined. This paper describes: (1) calculations of the sensitivity of barrier formation to vacuum conditions and to the presence of impurities in the neutral beams, (2) calculations of microwave penetration and absorption used to design the ECRH system, and (3) techniques to limit electron runaway to high energies by localized microwave beams and by relativistic detuning

A Step-by-Step Study of Formative Assessment

Science.gov (United States)

Pietsch, Laura

2013-01-01

This article presents a guide to the development of formative assessments for school librarians participating in professional learning communities (PLC). It describes librarians' reading of assigned books, meeting with their PLCs, and incorporation of learned strategies in their daily instruction. Central library service readers' regular visits to…

Miocene tectonic history of the Central Tauride intramontane basins, and the paleogeographic evolution of the Central Anatolian Plateau

Science.gov (United States)

Koç, Ayten; Kaymakci, Nuretdin; Van Hinsbergen, Douwe J. J.; Kuiper, Klaudia F.

2017-11-01

Marine Lower-Upper Miocene deposits uplifted to > 2 km elevation in the Tauride mountains of southern Turkey are taken as evidence for the rise of a nascent plateau. The dynamic causes of this uplift are debated, but generally thought to be a regional dynamic topographic effect of slab motions or slab break-off. Immediately adjacent to the high Tauride mountains lie the Central Tauride Intramontane Basins, which consist of Miocene and younger fluvio-lacustrine basins, at much lower elevations than the highly uplifted marine Miocene rocks. These basins include the previously analyzed Altınapa and Yalvaç basins, as well as the until now undescribed Ilgın Basin. In this paper, we aim to constrain the paleogeography of the Central Tauride Intramontane Basins and determine the role of the tectonics driving the formation of the high Miocene topography in southern Turkey. Therefore, we provide new data on the stratigraphy, sedimentology and structure of the continental Ilgın Basin. We provide an 40Ar/39Ar age of 11.61 ± 0.05 Ma for pumice deposits in the stratigraphy. We provide paleostress inversion analysis based on growth faults showing that the basin formed during multi-directional extension, with NE-SW to E-W dominating over subordinate Nsbnd S extension. We conclude that major, still-active normal faults like the Akşehir Fault also controlled Miocene Ilgın basin formation, with proximal facies close to the basin margins grading upwards and basinwards into lacustrine deposits representing the local depocenter. The Ilgın Basin was a local depocenter, but it may have connected with the adjacent Altınapa Basin during high lake levels in late Serravallian time. The Ilgın Basin and the other continental basins provide key constraints on the paleogeography and tectonic history of the region. These continental basins were likely close to the paleo-coastline during the Late Miocene after which there must have been major differential uplift of the Taurides. We

Galactic conformity and central/satellite quenching, from the satellite profiles of M* galaxies at 0.4 < z < 1.9 in the UKIDSS UDS

Science.gov (United States)

Hartley, W. G.; Conselice, C. J.; Mortlock, A.; Foucaud, S.; Simpson, C.

2015-08-01

We explore the redshift evolution of a curious correlation between the star formation properties of central galaxies and their satellites (`galactic conformity') at intermediate to high redshift (0.4 9.7, around central galaxies at the characteristic Schechter function mass, M ˜ M*. We fit the radial profiles of satellite number densities with simple power laws, finding slopes in the range -1.1 to -1.4 for mass-selected satellites, and -1.3 to -1.6 for passive satellites. We confirm the tendency for passive satellites to be preferentially located around passive central galaxies at 3σ significance and show that it exists to at least z ˜ 2. Meanwhile, the quenched fraction of satellites around star-forming galaxies is consistent with field galaxies of equal stellar masses. We find no convincing evidence for a redshift-dependent evolution of these trends. One simple interpretation of these results is that only passive central galaxies occupy an environment that is capable of independently shutting off star formation in satellite galaxies. By examining the satellites of higher stellar mass star-forming galaxies (log(M*/M⊙) > 11), we conclude that the origin of galactic conformity is unlikely to be exclusively due to the host dark matter halo mass. A halo-mass-independent correlation could be established by either formation bias or a more physical connection between central and satellite star formation histories. For the latter, we argue that a star formation (or active galactic nucleus) related outburst event from the central galaxy could establish a hot halo environment which is then capable of quenching both central and satellite galaxies.

Stratigraphic framework of Cambrian and Ordovician rocks in the central Appalachian Basin from Medina County, Ohio, through southwestern and south-central Pennsylvania to Hampshire County, West Virginia

Science.gov (United States)

Ryder, Robert T.; Harris, Anita G.; Repetski, John E.; revised and digitized by Crangle, Robert D.

2003-01-01

are identified by the following descriptive names: (1) sandstone, shale, limestone, and dolomite unit, (2) dolomite and sandstone unit, (3) limestone and black shale unit, and (4) shale and sandstone unit. Each of these units and their associated subunits thicken from west to east across the restored section to a maximum near the depositional axis of the Rome trough and then thin eastward to the end of the section. The sandstone, shale, limestone, and dolomite unit is largely confined to the asymmetric graben that marks the initial phase of the Rome trough. This unit is Early and Middle Cambrian in age and consists, in ascending order, of a basal sandstone unit (undrilled but probably present), the Tomstown Dolomite (undrilled but probably present), the Waynesboro Formation, and the Pleasant Hill Limestone and its equivalent lower one-third of the Elbrook Formation at the eastern end of the section. The dolomite and sandstone unit forms the core of the Cambrian and Ordovician sequence. In the Rome trough and on the adjoining South-central Pennsylvania arch, this unit consists, in ascending order, of the Middle and Upper Cambrian Warrior Formation and the equivalent upper two-thirds of the Elbrook Formation at the eastern end of the section, the Upper Cambrian Gatesburg Formation, and the Lower Ordovician and Middle Ordovician (Whiterockian and Chazyan) Beekmantown Group. West of the Ohio-West Virginia hinge zone, the dolomite and sandstone unit consists, in ascending order, of the Conasauga Formation of Janssens (1973), the Krysik sandstone of driller's usage, the B zone of Calvert (1964), the Knox Dolomite and the associated Rose Run Sandstone Member, and the Wells Creek Formation. The widespread Knox unconformity is located at the base of the Wells Creek Formation and at or near the top of the adjoining Beekmantown Group, except near the depositional axis of the Rome trough, where the unconformity seems to be absent. The limestone and black shale unit i

Biogeografía de los anfibios anuros de la región central de la República Argentina

Directory of Open Access Journals (Sweden)

Bridarolli, María E.

1994-01-01

Full Text Available The distribution of sixty anuran taxa in central Argentina (28°- 36°S, 60°-68°W is analyzed, as well as its correspondence with natural environments, taking into account phytogeographic formations, geomorphology, climatologic zones and zoogeographic regions. An isoline map of anurans diversity was constructed. High diversity occurs in the central-east zone of the study area, coincidently with plain environments and heterogenous phytogeographic formations; low values are found in homogenous phytogeographic formations. A dendrogram was obtained following UPGMA procedure, distinguishing 6 groups of phytogeographic associations based on amphibian distributions. A correspondence between natural environments and anurans presence is reported.

Sedimentary environments and stratigraphy of the carbonate-silicilastic deposits of the Shirgesht Formation: implications for eustasy and local tectonism in the Kalmard Block, Central Iran

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reza Mousavi-Harami

2015-09-01

Full Text Available   Introduction   Sedimentological and sequence stratigraphic analysis providing insight into the main relationships between sequence architecture and stacking pattern, syn/post-depositional tectonics, and eustatic sea-level fluctuations (Gawthorpe and Leeder 2000 Zecchin et al. 2003, 2004 Carpentier et al. 2007. Relative variations in sea level are due to tectonic activity and eustasy. The Shirgesht Formation in the Kalmard Block of Central Iran provides a useful case study for to determine the processes responsible on internal architecture and stacking pattern of depositional sequences in a half-graben basin. In the Shirgesht Formation, siliciclastic and carbonate successions of the Kalmard Basin, the cyclic stratigraphic record is the result of the complex interaction of regional uplift, eustasy, local tectonics, sediment supply, and sedimentary processes (Bayet-Goll 2009, 2014 Hosseini-Barzi and Bayet-Goll 2009.     Material & Methods   Lower Paleozoic successions in Tabas and Kalmard blocks from Central Iran share the faunal and floral characteristics with other Gondwana sectors such as south-western Europe and north Africa–Middle East (Ghaderi et al. 2009. The geology of these areas was outlined by Ruttner et al. (1968 and by Bruton et al. (2004. The Cambrian-Middle Triassic strata in the Kalmard Block were deposited in a shallow water platform that possesses lithologic dissimilarities with the Tabas area (Aghanabati 2004. The occurrence of two active faults indicates clearly that Kalmard basin formed a mobile zone throughout the Paleozoic so that lithostratigraphic units show considerably contrasting facies in comparison with Tabas basin (Hosseini-Barzi and Bayet-Goll 2009 Bayet-Goll 2014 . The Shirgesht Formation in the Block Kalmard is mainly composed of carbonate-siliciclastic successions that disconformability overlain Kalmard Formation (attributed to Pre-Cambrian and is underlain by Gachal (Carboniferous or

Sedimentary environments and stratigraphy of the carbonate-silicilastic deposits of the Shirgesht Formation: implications for eustasy and local tectonism in the Kalmard Block, Central Iran

Directory of Open Access Journals (Sweden)

aram bayetgoll

2015-10-01

Full Text Available Introduction   Sedimentological and sequence stratigraphic analysis providing insight into the main relationships between sequence architecture and stacking pattern, syn/post-depositional tectonics, and eustatic sea-level fluctuations (Gawthorpe and Leeder 2000; Zecchin et al. 2003, 2004; Carpentier et al. 2007. Relative variations in sea level are due to tectonic activity and eustasy. The Shirgesht Formation in the Kalmard Block of Central Iran provides a useful case study for to determine the processes responsible on internal architecture and stacking pattern of depositional sequences in a half-graben basin. In the Shirgesht Formation, siliciclastic and carbonate successions of the Kalmard Basin, the cyclic stratigraphic record is the result of the complex interaction of regional uplift, eustasy, local tectonics, sediment supply, and sedimentary processes (Bayet-Goll 2009, 2014; Hosseini-Barzi and Bayet-Goll 2009.     Material & Methods   Lower Paleozoic successions in Tabas and Kalmard blocks from Central Iran share the faunal and floral characteristics with other Gondwana sectors such as south-western Europe and north Africa–Middle East (Ghaderi et al. 2009. The geology of these areas was outlined by Ruttner et al. (1968 and by Bruton et al. (2004. The Cambrian-Middle Triassic strata in the Kalmard Block were deposited in a shallow water platform that possesses lithologic dissimilarities with the Tabas area (Aghanabati 2004. The occurrence of two active faults indicates clearly that Kalmard basin formed a mobile zone throughout the Paleozoic so that lithostratigraphic units show considerably contrasting facies in comparison with Tabas basin (Hosseini-Barzi and Bayet-Goll 2009; Bayet-Goll 2014 . The Shirgesht Formation in the Block Kalmard is mainly composed of carbonate-siliciclastic successions that disconformability overlain Kalmard Formation (attributed to Pre-Cambrian and is underlain by Gachal (Carboniferous or Rahdar (Devonian

Contesting State Forests in Post-Suharto Indonesia: Authority Formation, State Forest Land Dispute, and Power in Upland Central Java, Indonesia

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Anu Lounela

2012-01-01

Full Text Available This article explores the ongoing conflict over state forest land between the local population and the State Forestry Corporation (SFC in a village in upland Central Java with regard to authority formation. It looks at how different agents draw on different sources of authority in the course of the conflict and its negotiations. The principal questions are to what kind of sources of authority villagers refer to and how the formation of authority informs the relations between the state and society in the land dispute. The article is based on 11 months of ethnographic fieldwork and focuses on the central figure of Pak Wahid who took a leading position in the forest land dispute and in mobilising peasants in the village. The article argues that in post-Suharto Java, leadership in the struggle for state forest land at the village level is embedded in the interaction of Javanese ideas of power and authority as well as administrative authority. Due to political and institutional reforms, new sources of authority could be invoked while there are no real changes in the power relations within the village or between the SFC and the villagers. ----- Dieser Artikel untersucht den anhaltenden Konflikt um staatliche Waldflächen zwischen der lokalen Bevölkerung und der State Forestry Corporation (SFC in einem Dorf im Hochland von Zentral- Java in Bezug auf die Entwicklung von Autorität. Es wird untersucht, wie sich unterschiedliche AkteurInnen im Rahmen des Konflikts und dessen Verhandlung auf unterschiedliche Bezugsquellen von Autorität beziehen. Die zentralen Forschungsfragen in diesem Zusammenhang sind, auf welche Bezugsquellen von Autorität sich DorfbewohnerInnen beziehen und wie die Entwicklung von Autorität die Beziehungen zwischen Staat und Gesellschaft im Rahmen des Landkonflikts beeinflusst. Der Artikel basiert auf einer 11-monatigen ethnografischen Feldforschung und fokussiert auf die Person von Pak Wahid, der eine Schlüsselrolle im Konflikt

Early-middle Eocene birds from the Lillebaelt Clay Formation of Denmark

DEFF Research Database (Denmark)

Lindow, Bent Erik Kramer

2009-01-01

The marine Lillebaelt Clay Formation of central Denmark is of early-middle Eocene age (late Ypresian - middle Lutetian; microfossil zones NP 13-NP 15). Over 20 bird fossils collected by amateur palaeontologists have been acquired through the Danish national ‘Danekrae' fossil treasure trove...... Clay Formation deposits derive from just after the Early Eocene Climate Optimum, a period of global elevated temperatures resulting from rapid greenhouse warming. Comparison between this bird assemblage and the recently revised assemblage from the older (earliest Ypresian) Fur Formation of Denmark...

Halo histories versus Galaxy properties at z = 0 - I. The quenching of star formation

Science.gov (United States)

Tinker, Jeremy L.; Wetzel, Andrew R.; Conroy, Charlie; Mao, Yao-Yuan

2017-12-01

We test whether halo age and galaxy age are correlated at fixed halo and galaxy mass. The formation histories, and thus ages, of dark matter haloes correlate with their large-scale density ρ, an effect known as assembly bias. We test whether this correlation extends to galaxies by measuring the dependence of galaxy stellar age on ρ. To clarify the comparison between theory and observation, and to remove the strong environmental effects on satellites, we use galaxy group catalogues to identify central galaxies and measure their quenched fraction, fQ, as a function of large-scale environment. Models that match halo age to central galaxy age predict a strong positive correlation between fQ and ρ. However, we show that the amplitude of this effect depends on the definition of halo age: assembly bias is significantly reduced when removing the effects of splashback haloes - those haloes that are central but have passed through a larger halo or experienced strong tidal encounters. Defining age using halo mass at its peak value rather than current mass removes these effects. In Sloan Digital Sky Survey data, at M* ≳ 1010 M⊙ h-2, there is a ∼5 per cent increase in fQ from low-to-high densities, which is in agreement with predictions of dark matter haloes using peak halo mass. At lower stellar mass there is little to no correlation of fQ with ρ. For these galaxies, age matching is inconsistent with the data across the range of halo formation metrics that we tested. This implies that halo formation history has a small but statistically significant impact on quenching of star formation at high masses, while the quenching process in low-mass central galaxies is uncorrelated with halo formation history.

Oligocene Fluvio-Deltaic Depositional Environments Salin Sub-Basin, Central Myanmar

Science.gov (United States)

Gough, A.; Hall, R.

2017-12-01

A recent increase in accessibility for research in Myanmar has allowed rapid advancements in the understanding of the geology of the country. Evolving depositional environments can be reconstructed in largely unstudied Oligocene deposits of the Salin sub-basin, of the Central Myanmar Basin. Data has been collected through a fieldwork campaign to target well-exposed sediments along the western margin of the basin. The studied outcrops span approximately one hundred kilometres from north to south, and a series of sedimentary logs, palaeocurrent data, 2D panel diagrams, and samples for petrographical analysis have been collected and interpreted. The Oligocene formations studied include the Shwezetaw, Paduang, and Okhmintaung, each of which show a broadly southwards-trending fluvio-deltaic environment of deposition. Towards the north, the lower Rupelian Shwezetaw Formation comprises thick fluviatile sandstones which grade southwards through macrotidal-dominated fluvio-deltaic interbedded siltstones and rare sandstones, into marine sandstones. Overlying this, the upper Rupelian Paduang Formation grades rapidly from rare fluvial sandstones towards the north of the basin into deltaic and marine interbedded sandstones and siltstones to the south. This formation is more marine in nature, suggesting a minor transgression throughout the lower Oligocene. By the time of deposition of the Okhmintaung Formation in the Chattian the observed deposits solely represent a tidally-influenced deltaic depositional environment, with very little temporal variation, suggesting a stable sea level. Despite the relatively unchanging depositional environment, the formations are approximately 4000 m thick, suggesting that sedimentation kept pace with relatively rapid subsidence. This current study, which will combine depositional environment reconstruction, provenance, and sediment routing analysis, will provide important insights into both the tectonic setting and the huge sediment accumulation

Development of the Central Dogma Concept Inventory (CDCI) Assessment Tool

Science.gov (United States)

Newman, Dina L.; Snyder, Christopher W.; Fisk, J. Nick; Wright, L. Kate

2016-01-01

Scientific teaching requires scientifically constructed, field-tested instruments to accurately evaluate student thinking and gauge teacher effectiveness. We have developed a 23-question, multiple select--format assessment of student understanding of the essential concepts of the central dogma of molecular biology that is appropriate for all…

Homeostatic regulation of meiotic DSB formation by ATM/ATR

International Nuclear Information System (INIS)

Cooper, Tim J.; Wardell, Kayleigh; Garcia, Valerie; Neale, Matthew J.

2014-01-01

Ataxia–telangiectasia mutated (ATM) and RAD3-related (ATR) are widely known as being central players in the mitotic DNA damage response (DDR), mounting responses to DNA double-strand breaks (DSBs) and single-stranded DNA (ssDNA) respectively. The DDR signalling cascade couples cell cycle control to damage-sensing and repair processes in order to prevent untimely cell cycle progression while damage still persists [1]. Both ATM/ATR are, however, also emerging as essential factors in the process of meiosis; a specialised cell cycle programme responsible for the formation of haploid gametes via two sequential nuclear divisions. Central to achieving accurate meiotic chromosome segregation is the introduction of numerous DSBs spread across the genome by the evolutionarily conserved enzyme, Spo11. This review seeks to explore and address how cells utilise ATM/ATR pathways to regulate Spo11-DSB formation, establish DSB homeostasis and ensure meiosis is completed unperturbed

Homeostatic regulation of meiotic DSB formation by ATM/ATR

Energy Technology Data Exchange (ETDEWEB)

Cooper, Tim J.; Wardell, Kayleigh; Garcia, Valerie; Neale, Matthew J., E-mail: m.neale@sussex.ac.uk

2014-11-15

Ataxia–telangiectasia mutated (ATM) and RAD3-related (ATR) are widely known as being central players in the mitotic DNA damage response (DDR), mounting responses to DNA double-strand breaks (DSBs) and single-stranded DNA (ssDNA) respectively. The DDR signalling cascade couples cell cycle control to damage-sensing and repair processes in order to prevent untimely cell cycle progression while damage still persists [1]. Both ATM/ATR are, however, also emerging as essential factors in the process of meiosis; a specialised cell cycle programme responsible for the formation of haploid gametes via two sequential nuclear divisions. Central to achieving accurate meiotic chromosome segregation is the introduction of numerous DSBs spread across the genome by the evolutionarily conserved enzyme, Spo11. This review seeks to explore and address how cells utilise ATM/ATR pathways to regulate Spo11-DSB formation, establish DSB homeostasis and ensure meiosis is completed unperturbed.

Structur e and Functioning of Micr obial Community of Mineral Springs in Central Asia

Directory of Open Access Journals (Sweden)

Namsaraev B.B.

2003-12-01

Full Text Available The microbial mats of dif ferent types of springs in Central Asia (Zabaikalye and Mongolia are described. The species diversity of mat-formed phototrophic bacteria was determined. The rates of microbial destruction processes (sulfate reduction and methane formation were measured. An important role of bacteria and algae in the formation of mineral water composition was shown.

Studies on the Neogene Tertiary strata distributed in the central part of Tottori prefecture

International Nuclear Information System (INIS)

Yoshitani, Akihiko; Yoshizawa, Junko.

1978-01-01

The Neogene Tertiary strata, distributed in the central part of Tottori Prefecture, are volcano-stratigraphically classified, as shown in Figure 3. The Miocene strata are divided into Ojika formation and Mitoku formation in ascending order. Ojika formation, composed of plagio-rhyolitic pyroclastics and lavas, abuts against the basement rocks. Furthermore, some breaccias derived from the talus basal conglomerate beds are found in Ojika formation. Mitoku formation abuts both against the basement rocks and Ojika formation, and sometimes overlaps on the basement rocks. From the investigation into the Miocene strata, it is clarified that the depression took place prior to the volcanic activities at the earliest stage of the present Miocene sedimentary basin. (author)

Nuclear processing during star formation

International Nuclear Information System (INIS)

Newman, M.J.

1978-01-01

A preliminary survey was conducted of the thermonuclear energy release expected during star formation. The destruction of primordial deuterium provides substantial amounts of energy at surprisingly low temperatures, and must be considered in any meaningful treatment of star formation carried to stages in which the internal temperature exceeds a few hundred thousand degrees. Significant energy generation from consumption of initial lithium requires higher temperatures, of the order of a few million degrees. Depletion of primordial beryllium and boron may never provide an important energy source. The approach to equilibrium of the carbon--nitrogen cycle is dominant at temperatures approaching those characteristic of the central regions of main sequence stars. The present calculation should serve as a useful guide in choosing those nuclear processes to be included in a more detailed study. 8 figures, 2 tables

Carbonate microfacies of the San Juan Formation (Ordovician: Oepikodus evae and Oepikodus intermedius conodont zones), Niquivil, Central Precordillera, Province of San Juan (Argentina)

International Nuclear Information System (INIS)

Soria, T.; Beresi, M.; Mestre, A.; Heredia, S.; Rodríguez, M.C.

2017-01-01

This contribution presents the description and interpretation of carbonate microfacies of the San Juan Formation (Ordovician) at the Niquivil section, considering the stratigraphical interval between the Oepikodus evae and Oepikodus intermedius conodont zones. The distribution of the microfacies and the conodonts assemblages allow us to identify different sub-environments within the late Floian carbonate ramp of the Central Precordillera. Five microfacies were recognized from the base to the top: M1 Bioclastic mudstone-wackestone; M2 Bioclastic-peloidal wackestone; M3 Intra-bioclastic wackestone; M4 Intra-bioclastic packstone; M5 Peloidal grainstone. The vertical distribution of these microfacies indicates a shallowing trend of the carbonate ramp in the Niquivil section for this temporal interval, which suggests a middle ramp environment with low energy, without wave action, and that evolved towards the middle-inner ramp environment with more energy by wave action and development of tempestites. [es

D Central Line Extraction of Fossil Oyster Shells

Science.gov (United States)

Djuricic, A.; Puttonen, E.; Harzhauser, M.; Mandic, O.; Székely, B.; Pfeifer, N.

2016-06-01

Photogrammetry provides a powerful tool to digitally document protected, inaccessible, and rare fossils. This saves manpower in relation to current documentation practice and makes the fragile specimens more available for paleontological analysis and public education. In this study, high resolution orthophoto (0.5 mm) and digital surface models (1 mm) are used to define fossil boundaries that are then used as an input to automatically extract fossil length information via central lines. In general, central lines are widely used in geosciences as they ease observation, monitoring and evaluation of object dimensions. Here, the 3D central lines are used in a novel paleontological context to study fossilized oyster shells with photogrammetric and LiDAR-obtained 3D point cloud data. 3D central lines of 1121 Crassostrea gryphoides oysters of various shapes and sizes were computed in the study. Central line calculation included: i) Delaunay triangulation between the fossil shell boundary points and formation of the Voronoi diagram; ii) extraction of Voronoi vertices and construction of a connected graph tree from them; iii) reduction of the graph to the longest possible central line via Dijkstra's algorithm; iv) extension of longest central line to the shell boundary and smoothing by an adjustment of cubic spline curve; and v) integration of the central line into the corresponding 3D point cloud. The resulting longest path estimate for the 3D central line is a size parameter that can be applied in oyster shell age determination both in paleontological and biological applications. Our investigation evaluates ability and performance of the central line method to measure shell sizes accurately by comparing automatically extracted central lines with manually collected reference data used in paleontological analysis. Our results show that the automatically obtained central line length overestimated the manually collected reference by 1.5% in the test set, which is deemed

Middle-to-Upper Palaeolithic site formation processes at the Bordes-Fitte rockshelter (Central France)

DEFF Research Database (Denmark)

Aubry, Thierry; Dimuccio, Luca Antonio; Buylaert, Jan-Pieter

2014-01-01

. In this article we use the Middle and Early Upper Palaeolithic archaeo-stratigraphic record from the Bordes-Fitte rockshelter (les Roches d'Abilly site, Central France), a Bayesian analysis of the ages obtained by accelerator mass spectrometry radiocarbon on ultrafiltered collagen and by luminescence on quartz...

Diverse Formation Mechanisms for Compact Galaxies

Science.gov (United States)

Kim, Jin-Ah; Paudel, Sanjaya; Yoon, Suk-Jin

2018-01-01

Compact, quenched galaxies such as M32 are unusual ones located off the mass - size scaling relation defined by normal galaxies. Still, their formation mechanisms remain unsolved. Here we investigate the evolution of ~100 compact, quenched galaxies at z = 0 identified in the Illustris cosmological simulation. We identify three ways for a galaxy to become a compact one and, often, multiple mechanisms operate in a combined manner. First, stripping is responsible for making about a third of compact galaxies. Stripping removes stars from galaxies, usually while keeping their sizes intact. About one third are galaxies that cease their growth early on after entering into more massive, gigantic halos. Finally, about half of compact galaxies, ~ 35 % of which turn out to undergo stripping, experience the compaction due to the highly centrally concentrated star formation. We discuss the evolutionary path of compact galaxies on the mass – size plane for each mechanism in a broader context of dwarf galaxy formation and evolution.

The Russian State, Lenin and the Central Asia

Directory of Open Access Journals (Sweden)

E. M. Korhzokin

2016-01-01

Full Text Available Central Asian nations faced a challenge of state-building objectives after the collapse of the USSR. However, it was a complicated task, because those nations were parts of the Russian and, lately, the Soviet state. State-building objectives include the creation of new historical narrative. Central Asia is now experiencing the process that is called "national novel" in the Western European historiography. Central Asian national variants of historical narratives serve as a conceptual basis for the writing of school and university textbooks. The introduction of ideological constructs through the education system is carried out everywhere. However, it is important to note that inevitable ideological indoctrination should not undermine scientific essence of textbooks. Politics of nation formation and the preservation of its identity is implemented and fostered by states carefully as well as clumsy. There is no doubt that there is an inevitable and practical need for constructing "national novel" in the new states. But historical politics should not ignore some of the methodological and at the same time mental traps that exist in the field of studying the history of the peoples of Central Asia in the period of the Russian Empire.

Constrained Magnetostratigraphic Dating of a Continental Middle Miocene Section in the Arid Central Asia

Directory of Open Access Journals (Sweden)

Verena Verestek

2018-05-01

Full Text Available The Neogene succession of the Aktau Mountains in the Ili Basin, southeast Kazakhstan, is a terrestrial archive well suited for researching the role of Central Asia in Miocene climate evolution. We present an integrated approach for dating the well-exposed Bastau Formation, based on magnetostratigraphy and constraints from cyclostratigraphy and biostratigraphy. Stepwise demagnetization yielded characteristic remanence directions that are consistent with those expected for the Miocene in Central Asia. The reddish-colored alluvial floodplain deposits and gray lacustrine deposits show partly complex magnetic behavior with magnetite and hematite as the main magnetic carriers, with variable demagnetization behavior and non-dipolar normal and reverse polarity directions. The observed magnetic properties are best explained by depositional variability and magneto-mineralogical alteration effects of both dissolution and neo-formation of magnetite, including significant secondary magnetization. The mean of reverse polarity directions is flatter than the expected Middle Miocene Earth magnetic field, which is an indicator for the existence of inclination shallowing that supports a primary origin. Detailed rock magnetic analyses are used to analyze the nature of the characteristic remanent magnetization and to discriminate primary and secondary remanence directions in order to obtain a reliable magnetostratigraphic result. The proposed age of 15.3–13.9 Ma for the Bastau Formation corresponds to the known biostratigraphic setting, matches with typical sedimentation rates of foreland basins in Central Asia, and coincides with spectral analysis of geochemical proxies of that section. The resulting age model serves as a robust framework for paleoclimate reconstruction of Neogene climate dynamics in Central Asia.

Stream and Aquifer Biology of South-Central Texas - A Literature Review, 1973-97

National Research Council Canada - National Science Library

Ourso, Robert T; Hornig, C. E

2000-01-01

This report summarizes in table format 32 aquatic vertebrate (primarily fish), 54 aquatic invertebrate, and 13 aquatic plant studies available for the area of the South-Central Texas study unit of the U.S...

The geometry and stratigraphic position of the Maassluis Formation (western Netherlands and southeastern North Sea)

NARCIS (Netherlands)

Jansen, H.S.M.; Huizer, J.; Dijkmans, J.W.A.; Mesdag, C.; Hinte, J.E. van

2004-01-01

The geometry and depositional history of the Maassluis Formation is described from an East-West oriented transect located in the west-central Netherlands and P- and Q-blocks in the Dutch offshore area. The Late Pliocene to Early Pleistocene Maassluis Formation was deposited under near coastal marine

Depositional conditions of the coal-bearing Hirka Formation beneath ...

Indian Academy of Sciences (India)

This work focuses on the relationship between the coal deposition and explosive volcanism of the Miocene basin, NW central Anatolia, Turkey. The coal-bearing Hirka Formation was deposited over the Galatian Andesitic Complex and/or massive lagoonal environments during the Miocene. The investigated lignite is a high ...

The SAMI Galaxy Survey: spatially resolving the main sequence of star formation

Science.gov (United States)

Medling, Anne M.; Cortese, Luca; Croom, Scott M.; Green, Andrew W.; Groves, Brent; Hampton, Elise; Ho, I.-Ting; Davies, Luke J. M.; Kewley, Lisa J.; Moffett, Amanda J.; Schaefer, Adam L.; Taylor, Edward; Zafar, Tayyaba; Bekki, Kenji; Bland-Hawthorn, Joss; Bloom, Jessica V.; Brough, Sarah; Bryant, Julia J.; Catinella, Barbara; Cecil, Gerald; Colless, Matthew; Couch, Warrick J.; Drinkwater, Michael J.; Driver, Simon P.; Federrath, Christoph; Foster, Caroline; Goldstein, Gregory; Goodwin, Michael; Hopkins, Andrew; Lawrence, J. S.; Leslie, Sarah K.; Lewis, Geraint F.; Lorente, Nuria P. F.; Owers, Matt S.; McDermid, Richard; Richards, Samuel N.; Sharp, Robert; Scott, Nicholas; Sweet, Sarah M.; Taranu, Dan S.; Tescari, Edoardo; Tonini, Chiara; van de Sande, Jesse; Walcher, C. Jakob; Wright, Angus

2018-04-01

We present the ˜800 star formation rate maps for the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey based on H α emission maps, corrected for dust attenuation via the Balmer decrement, that are included in the SAMI Public Data Release 1. We mask out spaxels contaminated by non-stellar emission using the [O III]/H β, [N II]/H α, [S II]/H α, and [O I]/H α line ratios. Using these maps, we examine the global and resolved star-forming main sequences of SAMI galaxies as a function of morphology, environmental density, and stellar mass. Galaxies further below the star-forming main sequence are more likely to have flatter star formation profiles. Early-type galaxies split into two populations with similar stellar masses and central stellar mass surface densities. The main-sequence population has centrally concentrated star formation similar to late-type galaxies, while galaxies >3σ below the main sequence show significantly reduced star formation most strikingly in the nuclear regions. The split populations support a two-step quenching mechanism, wherein halo mass first cuts off the gas supply and remaining gas continues to form stars until the local stellar mass surface density can stabilize the reduced remaining fuel against further star formation. Across all morphologies, galaxies in denser environments show a decreased specific star formation rate from the outside in, supporting an environmental cause for quenching, such as ram-pressure stripping or galaxy interactions.

Strangeness production in nuclear collisions: Color rope formations?

International Nuclear Information System (INIS)

Toneev, V.D.; Amelin, N.S.; Csernai, L.P.; Gudima, K.K.; Sivoklokov, S.Yu.

1992-12-01

Strangeness production at SPS-CERN energies is studied within the Quark Gluon String Model. This analysis indicates that the observed shape of rapidity and transverse mass distributions are reproduced fairly well for both peripheral and central heavy ion collisions. However, for central collisions the model underpredicts strange particles abundance by a factor of about 2:2:4 for K S 0 , Λ and anti Λ, respectively. This discrepancy can be considered as a possible manifestation of string-string interactions of a collective type similar to the formation of a color rope. The model predictions for coming experiments with the Pb beam at CERN are given. (orig.)

Polyphase Rifting and Breakup of the Central Mozambique Margin

Science.gov (United States)

Senkans, Andrew; Leroy, Sylvie; d'Acremont, Elia; Castilla, Raymi

2017-04-01

The breakup of the Gondwana supercontinent resulted in the formation of the Central Mozambique passive margin as Africa and Antarctica were separated during the mid-Jurassic period. The identification of magnetic anomalies in the Mozambique Basin and Riiser Larsen Sea means that post-oceanisation plate kinematics are well-constrained. Unresolved questions remain, however, regarding the initial fit, continental breakup process, and the first relative movements of Africa and Antarctica. This study uses high quality multi-channel seismic reflection profiles in an effort to identify the major crustal domains in the Angoche and Beira regions of the Central Mozambique margin. This work is part of the integrated pluri-disciplinary PAMELA project*. Our results show that the Central Mozambique passive margin is characterised by intense but localised magmatic activity, evidenced by the existence of seaward dipping reflectors (SDR) in the Angoche region, as well as magmatic sills and volcanoclastic material which mark the Beira High. The Angoche region is defined by a faulted upper-continental crust, with the possible exhumation of lower crustal material forming an extended ocean-continent transition (OCT). The profiles studied across the Beira high reveal an offshore continental fragment, which is overlain by a pre-rift sedimentary unit likely to belong to the Karoo Group. Faulting of the crust and overlying sedimentary unit reveals that the Beira High has recorded several phases of deformation. The combination of our seismic interpretation with existing geophysical and geological results have allowed us to propose a breakup model which supports the idea that the Central Mozambique margin was affected by polyphase rifting. The analysis of both along-dip and along-strike profiles shows that the Beira High initially experienced extension in a direction approximately parallel to the Mozambique coastline onshore of the Beira High. Our results suggest that the Beira High results

Neural Activity During The Formation Of A Giant Auditory Synapse

NARCIS (Netherlands)

M.C. Sierksma (Martijn)

2018-01-01

markdownabstractThe formation of synapses is a critical step in the development of the brain. During this developmental stage neural activity propagates across the brain from synapse to synapse. This activity is thought to instruct the precise, topological connectivity found in the sensory central

Geochemical, isotopic, and zircon (U-Pb, O, Hf isotopes) evidence for the magmatic sources of the volcano-plutonic Ollo de Sapo Formation, Central Iberia

Energy Technology Data Exchange (ETDEWEB)

Montero, P.; Talavera, C.; Bea, F.

2017-07-01

The Ollo de Sapo Formation comprises variably metamorphosed felsic peraluminous volcanic rocks and highlevel granites that crop out over some 600km from the Cantabrian coast to central Spain in the northern part of the Central Iberian Zone. The Ollo de Sapo magmatism is not obviously connected with any major tectonic or metamorphic event so its origin is controversial. Some authors, based on trace-elements, have proposed that the Ollo de Sapo magmas originated in a supra-subduction setting but others, based on abnormally high zircon inheritance and field and structural data, favored a rifting environment. Here we present new oxygen and hafnium isotope data from the very characteristic Ollo the Sapo zircons, which in most cases, consist of ca. 485Ma rims and ca. 590-615Ma cores. We found that the Cambrian-Ordovician rims yielded unimodal distributions that cluster around ∂18O = 10, typical of S-type magmas formed from melting of altered crust. The Ediacaran cores, in contrast, cluster around ∂18O = 6.5, consistent with being arc-magmas. Rims and cores have the same average Hf isotope composition, but the rims are considerably more uniform. These data, coupled with existing wholerock element and Sr and Nd isotopic data, indicate that the Ollo de Sapo were S-type magmas that resulted from anatexis of younger-than-600Ma immature sediments mostly derived from different Ediacaran igneous rocks with a wide range of Hf isotope composition.

Geochemical, isotopic, and zircon (U-Pb, O, Hf isotopes) evidence for the magmatic sources of the volcano-plutonic Ollo de Sapo Formation, Central Iberia

International Nuclear Information System (INIS)

Montero, P.; Talavera, C.; Bea, F.

2017-01-01

The Ollo de Sapo Formation comprises variably metamorphosed felsic peraluminous volcanic rocks and highlevel granites that crop out over some 600km from the Cantabrian coast to central Spain in the northern part of the Central Iberian Zone. The Ollo de Sapo magmatism is not obviously connected with any major tectonic or metamorphic event so its origin is controversial. Some authors, based on trace-elements, have proposed that the Ollo de Sapo magmas originated in a supra-subduction setting but others, based on abnormally high zircon inheritance and field and structural data, favored a rifting environment. Here we present new oxygen and hafnium isotope data from the very characteristic Ollo the Sapo zircons, which in most cases, consist of ca. 485Ma rims and ca. 590-615Ma cores. We found that the Cambrian-Ordovician rims yielded unimodal distributions that cluster around ∂18O = 10, typical of S-type magmas formed from melting of altered crust. The Ediacaran cores, in contrast, cluster around ∂18O = 6.5, consistent with being arc-magmas. Rims and cores have the same average Hf isotope composition, but the rims are considerably more uniform. These data, coupled with existing wholerock element and Sr and Nd isotopic data, indicate that the Ollo de Sapo were S-type magmas that resulted from anatexis of younger-than-600Ma immature sediments mostly derived from different Ediacaran igneous rocks with a wide range of Hf isotope composition.

Secondary organic aerosol formation from ambient air in an oxidation flow reactor in central Amazonia

Science.gov (United States)

Palm, Brett B.; de Sá, Suzane S.; Day, Douglas A.; Campuzano-Jost, Pedro; Hu, Weiwei; Seco, Roger; Sjostedt, Steven J.; Park, Jeong-Hoo; Guenther, Alex B.; Kim, Saewung; Brito, Joel; Wurm, Florian; Artaxo, Paulo; Thalman, Ryan; Wang, Jian; Yee, Lindsay D.; Wernis, Rebecca; Isaacman-VanWertz, Gabriel; Goldstein, Allen H.; Liu, Yingjun; Springston, Stephen R.; Souza, Rodrigo; Newburn, Matt K.; Lizabeth Alexander, M.; Martin, Scot T.; Jimenez, Jose L.

2018-01-01

Secondary organic aerosol (SOA) formation from ambient air was studied using an oxidation flow reactor (OFR) coupled to an aerosol mass spectrometer (AMS) during both the wet and dry seasons at the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) field campaign. Measurements were made at two sites downwind of the city of Manaus, Brazil. Ambient air was oxidized in the OFR using variable concentrations of either OH or O3, over ranges from hours to days (O3) or weeks (OH) of equivalent atmospheric aging. The amount of SOA formed in the OFR ranged from 0 to as much as 10 µg m-3, depending on the amount of SOA precursor gases in ambient air. Typically, more SOA was formed during nighttime than daytime, and more from OH than from O3 oxidation. SOA yields of individual organic precursors under OFR conditions were measured by standard addition into ambient air and were confirmed to be consistent with published environmental chamber-derived SOA yields. Positive matrix factorization of organic aerosol (OA) after OH oxidation showed formation of typical oxidized OA factors and a loss of primary OA factors as OH aging increased. After OH oxidation in the OFR, the hygroscopicity of the OA increased with increasing elemental O : C up to O : C ˜ 1.0, and then decreased as O : C increased further. Possible reasons for this decrease are discussed. The measured SOA formation was compared to the amount predicted from the concentrations of measured ambient SOA precursors and their SOA yields. While measured ambient precursors were sufficient to explain the amount of SOA formed from O3, they could only explain 10-50 % of the SOA formed from OH. This is consistent with previous OFR studies, which showed that typically unmeasured semivolatile and intermediate volatility gases (that tend to lack C = C bonds) are present in ambient air and can explain such additional SOA formation. To investigate the sources of the unmeasured SOA-forming gases during this campaign

The euro and the European Central Bank

OpenAIRE

Jeffrey M. Wrase

1999-01-01

The formation of a monetary union by 11 European countries has received a lot of notice from the press since January 1, 1999, when the union's common currency, the euro, was officially introduced. To facilitate adoption of a single currency, these same countries have established a central bank that sets a common monetary policy for the members of the monetary union. In this article, Jeff Wrase gives some background on the European monetary union, outlines the procedure for introduction of the...

Centralized vs. de-centralized multinationals and taxes

OpenAIRE

Nielsen, Søren Bo; Raimondos-Møller, Pascalis; Schjelderup, Guttorm

2005-01-01

The paper examines how country tax differences affect a multinational enterprise's choice to centralize or de-centralize its decision structure. Within a simple model that emphasizes the multiple conflicting roles of transfer prices in MNEs – here, as a strategic pre-commitment device and a tax manipulation instrument –, we show that (de-)centralized decisions are more profitable when tax differentials are (small) large. Keywords: Centralized vs. de-centralized decisions, taxes, MNEs. ...

3D CENTRAL LINE EXTRACTION OF FOSSIL OYSTER SHELLS

Directory of Open Access Journals (Sweden)

A. Djuricic

2016-06-01

Full Text Available Photogrammetry provides a powerful tool to digitally document protected, inaccessible, and rare fossils. This saves manpower in relation to current documentation practice and makes the fragile specimens more available for paleontological analysis and public education. In this study, high resolution orthophoto (0.5 mm and digital surface models (1 mm are used to define fossil boundaries that are then used as an input to automatically extract fossil length information via central lines. In general, central lines are widely used in geosciences as they ease observation, monitoring and evaluation of object dimensions. Here, the 3D central lines are used in a novel paleontological context to study fossilized oyster shells with photogrammetric and LiDAR-obtained 3D point cloud data. 3D central lines of 1121 Crassostrea gryphoides oysters of various shapes and sizes were computed in the study. Central line calculation included: i Delaunay triangulation between the fossil shell boundary points and formation of the Voronoi diagram; ii extraction of Voronoi vertices and construction of a connected graph tree from them; iii reduction of the graph to the longest possible central line via Dijkstra’s algorithm; iv extension of longest central line to the shell boundary and smoothing by an adjustment of cubic spline curve; and v integration of the central line into the corresponding 3D point cloud. The resulting longest path estimate for the 3D central line is a size parameter that can be applied in oyster shell age determination both in paleontological and biological applications. Our investigation evaluates ability and performance of the central line method to measure shell sizes accurately by comparing automatically extracted central lines with manually collected reference data used in paleontological analysis. Our results show that the automatically obtained central line length overestimated the manually collected reference by 1.5% in the test set, which

Reduction mammoplasty as a treatment for symptomatic central venous stenosis

Directory of Open Access Journals (Sweden)

Denise Seok Fun Fok

2018-03-01

Full Text Available Central venous stenosis is a rare cause of unilateral breast edema occurring in hemodialysis patients that needs to be differentiated from other differential diagnoses, including, but not limited to, inflammatory breast carcinoma, mastitis, lymphedema, and congestive heart failure. All reports of similar cases in the available literature have described improvement or resolution of the edema after treatment. Herein, we report and discuss the pathophysiology of breast edema formation in a patient who presented with massive left-sided breast edema 7 years after being diagnosed with central venous stenosis. Medical and minimally invasive therapy had not been successful, so she underwent reduction mammoplasty to relieve the symptoms.

STAR FORMATION HISTORY AND CHEMICAL EVOLUTION OF THE SEXTANS DWARF SPHEROIDAL GALAXY

International Nuclear Information System (INIS)

Lee, Myung Gyoon; Yuk, In-Soo; Park, Hong Soo; Harris, Jason; Zaritsky, Dennis

2009-01-01

We present the star formation history (SFH) and chemical evolution of the Sextans dSph galaxy as a function of a galactocentric distance. We derive these from the VI photometry of stars in the 42' x 28' field using the SMART model developed by Yuk and Lee and adopting a closed-box model for chemical evolution. For the adopted age of Sextans 15 Gyr, we find that >84% of the stars formed prior to 11 Gyr ago, significant star formation extends from 15 to 11 Gyr ago (∼ 65% of the stars formed 13-15 Gyr ago, while ∼ 25% formed 11-13 Gyr ago), detectable star formation continued to at least 8 Gyr ago, the SFH is more extended in the central regions than the outskirts, and the difference in star formation rates between the central and outer regions is most marked 11-13 Gyr ago. Whether blue straggler stars are interpreted as intermediate-age main-sequence stars affects conclusions regarding the SFH for times 4-8 Gyr ago, but this is at most only a trace population. We find that the metallicity of the stars increased rapidly up to [Fe/H] = -1.6 in the central region and to [Fe/H] = -1.8 in the outer region within the first Gyr, and has varied slowly since then. The abundance ratios of several elements derived in this study are in good agreement with the observational data based on the high-resolution spectroscopy in the literature. We conclude that the primary driver for the radial gradient of the stellar population in this galaxy is the SFH, which self-consistently drives the chemical enrichment history.

Multigenerational Perspectives on Family Formation Behaviour

DEFF Research Database (Denmark)

Loft, Lisbeth Trille Gylling

2014-01-01

The transformed opportunity structure individuals have experienced over the course of the 20th century has not only changed family life, but also led to increased educational requirements, higher expectations of social mobility in the labor market, and overall perceived prospects of a healthier...... life. Moreover, presence of generational transmission of family formation behavior such as cohabitation, age at first marriage and childbearing has been widely documented. Thus, it has become more appropriate to approach family life events in a non-linear manner by emphasizing the existence of various...... family formation pathways, and to study these pathways from a generational point of view. Drawing on a life course perspective and by means of rich multigenerational longitudinal data combined with data from the Danish central population registers, this study examines multigenerational transmission...

Star formation in evolving molecular clouds

Science.gov (United States)

Völschow, M.; Banerjee, R.; Körtgen, B.

2017-09-01

Molecular clouds are the principle stellar nurseries of our universe; they thus remain a focus of both observational and theoretical studies. From observations, some of the key properties of molecular clouds are well known but many questions regarding their evolution and star formation activity remain open. While numerical simulations feature a large number and complexity of involved physical processes, this plethora of effects may hide the fundamentals that determine the evolution of molecular clouds and enable the formation of stars. Purely analytical models, on the other hand, tend to suffer from rough approximations or a lack of completeness, limiting their predictive power. In this paper, we present a model that incorporates central concepts of astrophysics as well as reliable results from recent simulations of molecular clouds and their evolutionary paths. Based on that, we construct a self-consistent semi-analytical framework that describes the formation, evolution, and star formation activity of molecular clouds, including a number of feedback effects to account for the complex processes inside those objects. The final equation system is solved numerically but at much lower computational expense than, for example, hydrodynamical descriptions of comparable systems. The model presented in this paper agrees well with a broad range of observational results, showing that molecular cloud evolution can be understood as an interplay between accretion, global collapse, star formation, and stellar feedback.

Electron internal transport barrier formation and dynamics in the plasma core of the TJ-II stellarator

Energy Technology Data Exchange (ETDEWEB)

Estrada, T [Laboratorio Nacional de Fusion por Confinamiento Magnetico, Asociacion Euratom-CIEMAT, 28040 Madrid (Spain); Krupnik, L [Institute of Plasma Physics, NSC ' KIPT' , Kharkov (Ukraine); Dreval, N [Institute of Plasma Physics, NSC ' KIPT' , Kharkov (Ukraine); Melnikov, A [Institute of Nuclear Fusion, RRC ' Kurchatov Institute' , Moscow, Russia (Russian Federation); Khrebtov, S M [Institute of Plasma Physics, NSC ' KIPT' , Kharkov (Ukraine); Hidalgo, C [Laboratorio Nacional de Fusion por Confinamiento Magnetico, Asociacion Euratom-CIEMAT, 28040 Madrid (Spain); Milligen, B van [Laboratorio Nacional de Fusion por Confinamiento Magnetico, Asociacion Euratom-CIEMAT, 28040 Madrid (Spain); Castejon, F [Laboratorio Nacional de Fusion por Confinamiento Magnetico, Asociacion Euratom-CIEMAT, 28040 Madrid (Spain); AscasIbar, E [Laboratorio Nacional de Fusion por Confinamiento Magnetico, Asociacion Euratom-CIEMAT, 28040 Madrid (Spain); Eliseev, L [Institute of Nuclear Fusion, RRC ' Kurchatov Institute' , Moscow, Russia (Russian Federation); Chmyga, A A [Institute of Plasma Physics, NSC ' KIPT' , Kharkov (Ukraine); Komarov, A D [Institute of Plasma Physics, NSC ' KIPT' , Kharkov (Ukraine); Kozachok, A S [Institute of Plasma Physics, NSC ' KIPT' , Kharkov (Ukraine); Tereshin, V [Institute of Plasma Physics, NSC ' KIPT' , Kharkov (Ukraine)

2004-01-01

The influence of magnetic topology on the formation of electron internal transport barriers (e-ITBs) has been studied experimentally in electron cyclotron heated plasmas in the stellarator TJ-II. e-ITB formation is characterized by an increase in core electron temperature and plasma potential. The positive radial electric field increases by a factor of 3 in the central plasma region when an e-ITB forms. The experiments reported demonstrate that the formation of an e-ITB depends on the magnetic configuration. Calculations of the modification of the rotational transform due to plasma current lead to the interpretation that the formation of an e-ITB can be triggered by positioning a low order rational surface close to the plasma core region. In configurations without any central low order rational, no barrier is formed for any accessible value of heating power. Different mechanisms associated with neoclassical/turbulent bifurcations and kinetic effects are put forward to explain the impact of magnetic topology on radial electric fields and confinement.

Centrality and get-richer mechanisms in interregional knowledge networks

DEFF Research Database (Denmark)

Mitze, Timo; Strotebeck, Falk

2018-01-01

and relate them to sector-region-specific and overall regional attributes in an explorative regression approach. The results indicate that fit-get-richer mechanisms proxied by regional endowments and policy factors such as biotech research and development funding categories and human capital matter...... for network formation. We find that these correlations differ across centrality measures and that empirical evidence for a richer-get-richer mechanism is limited....

The Origin of the Chinese Central Tianshan Block in the Southern Central Asian Orogenic Belt: Evidence from Detrital Zircon Study

Science.gov (United States)

Huang, Z.; Long, X.; Yuan, C.

2016-12-01

The Chinese Central Tianshan Block (CTB) is one of the oldest continental fragments in the southern Central Asian Orogenic Belt (CAOB). Although it is vital for understanding the evolution of the CAOB, its origin has been poorly studied. The CTB was previously suggested to have been originated from the North China, the South China, the Tarim cratons or the East European Craton (Baltica). A total of 165 concordant U-Pb and Hf isotopic analyses of detrital zircon are obtained from three meta-sediments in the CTB, including one meta-sandstone from Xingxingxia formation and one meta-sandstone as well as one quartzite from Kawabulake formation. Detrital zircon grains from the Xingxingxia and Kawabulake formations are dominated by respective youngest age populations at 1002 Ma and 930-960 Ma, providing constraints on the maximum depositional ages for these two formations. Zircon grains from the meta-sediments have very similar age distributions, with two dominant peaks at 0.93-1.0 Ga and 1.0-1.6 Ga and a minor peak at 2.3-2.7 Ga. They have similar Hf isotopic signatures, suggesting that the meta-sediments in the CTB share similar sedimentary provenance. The early Neoproterozoic detrital zircon grains are mainly local-derived, whereas the Paleo-Mesoproterozoic grains are both autochthonous and allochthonous. The occurrence of these Mesoproterozoic and Neoproterozoic zircon grains are coincident with the Nuna breakup and the Rodinia assembly. This suggests that the CTB might experience the tectonic switching of the Nuna to the Rodinia. The distinct Meso-Neoproterozoic age patterns and Hf isotopic compositions of these detrital grains from the CTB and the surrounding blocks indicate that the CTB was not located close to the North China, the South China or the Tarim cratons in Precambrian. Our new data suggest that the CTB was most likely once a part of the East European Craton before the Neoproterozoic. This study was supported by National Basic Research Program of China

Le Carbonifère du Maroc central : les formations de Migoumess, de Tirhela et d'Idmarrach. Lithologie, biostratigraphie et conséquences géodynamiquesThe Carboniferous formations of Migoumess, Tirhela and Idmarrach (central Morocco): lithology, biostratigraphy and geodynamic consequences

Science.gov (United States)

Berkhli, Mostafa; Vachard, Daniel

2002-01-01

New biostratigraphical data based on foraminifers, algae and pseudo-algae indicate that the limestone pebbles of the channelized polygenic conglomerates of the Migoumess formation contain Late Visean (V3b γ-V3c) assemblages. That confirms the Westphalian age attributed to this formation by Hollard [Zdt. Geol. Ges. 129 (1978) 495-512]. The Tournaisian age assigned to it by palynology [C. R. Acad. Sci. Paris, série II 310 (1990) 1573-1576] cannot be retained. The Tirhela formation, Late Visean and Serpukhovian (E1) in age, is coeval with the Akerchi formation [Berkhli, thèse d'État, 1999; Berkhli et al., J. Afr. Earth Sci. (accepté)]. The Idmarrach formation, mapped as a thrust sheet [C. R. Acad. Sci. Paris, série II 310 (1990) 1573-1576], is dated as Serpukhovian (E1) and its thrusting is consequently post-Serpukhovian. Palaeogeographic and geodynamic consequences are listed. To cite this article: M. Berkhli, D. Vachard, C. R. Geoscience 334 (2002) 67-72

Origin of dolomites in a downslope biostrome, Jefferson Formation (Frasnian), central Idaho: evidence from REE patterns, stable isotopes, and petrography

Energy Technology Data Exchange (ETDEWEB)

Dorobek, S.L.

1987-08-01

A completely dolomitized coral-stromatoporoid biostrome occurs at the top of the Dark Dolomite member of the Jefferson Formation (Frasnian) at Grandview Canyon, Lost River Range, central Idaho. The biostrome overlies a thick sequence of dolostones that were deposited in slope to deep ramp settings. The biostrome, therefore, formed in an open marine setting after shallowing of deep water environments. Zoned dolospar cement fills dissolution vugs and tectonic fractures. Stable isotopes for zoned dolospar are -13.1 to -6.5 per thousand delta/sup 18/O (average - 11.5) and -1.5 to -0.1 per thousand delta/sup 13/C (average -0.4). REE patterns for zoned dolospar have positive Ce anomalies, but total REE abundance is similar to REE abundance for replacive dolomites. Stratigraphic occurrence in an open marine setting, stable isotopes, and REE patterns suggest replacive dolomite phases formed during shallow burial diagenesis with significant involvement of nonevaporated sea water. More negative Ce anomalies near the top of the biostrome suggest a diagenetic overprint by oxidizing meteoric waters. Zoned dolospar probably formed from warmer, reducing burial fluids. Carbon for zoned dolospar probably was recycled from preexisting dolomite. These data may be useful for interpreting the origin of other anomalous platform dolostones.

Eustatic control on epicontinental basins: The example of the Stuttgart Formation in the Central European Basin (Middle Keuper, Late Triassic)

Science.gov (United States)

Franz, M.; Nowak, K.; Berner, U.; Heunisch, C.; Bandel, K.; Röhling, H.-G.; Wolfgramm, M.

2014-11-01

The deposition of the Stuttgart Formation ('Schilfsandstein'), commonly considered as a type-example of the Carnian Pluvial Event, was controlled by high frequent 4th order sequences that resulted in pre-, intra- and post-Schilfsandstein transgressions from Tethyan waters into the epicontinental Central European Basin (CEB). The pre-Schilfsandstein transgression flooded the CEB trough gates to the Southeast and resulted in a wide-spread inland sea that was characterised by increased biological productivity, predominantly oxic conditions and enabled the immigration of euryhaline marine fauna with plankton, ostracodes, fishes, bivalves and the gastropods Omphaloptychia suebica n. sp. and Settsassia stuttgartica n. sp. The rather short-term intra- and post-Schilfsandstein transgressions flooded the CEB from the Southwest and Southeast and established a shallow brackish inland sea that stretched up to North Germany. Both, the 4th and 3rd order sequences derived from the succession in the CEB correlate well with those derived from successions of Tethyan shelfs. Therefore pronounced circum-Tethyan eustatic cycles are evidenced and may have had considerable impact on prominent middle Carnian events: Reingraben turnover, Carnian Pluvial Event, Carnian Crisis and Mid Carnian Wet Intermezzo. The broad circum-Tethyan evidence of 106-year scale cycles suggests glacioeustatic sea-level changes even in the Triassic Greenhouse period.

Radiative Hydrodynamic Simulations of In Situ Star Formation in the Galactic Center

Science.gov (United States)

Frazer, Chris; Heitsch, Fabian

2018-01-01

Many stars observed in the Galactic Center (GC) orbit the supermassive black hole (SMBH), Sagittarius A*, in a region where the extreme gravitational field is expected to inhibit star formation. Yet, many of these stars are young which favors an in situ formation scenario. Previous numerical work on this topic has focused on two possible solutions. First, the tidal capture of a > 10^4 Msun infalling molecular cloud by an SMBH may result in the formation of a surrounding gas disk which then rapidly cools and forms stars. This process results in stellar populations that are consistent with the observed stellar disk in the GC. Second, dense gas clumps of approximately 100 Msun on highly eccentric orbits about an SMBH can experience sparks of star formation via orbital compressions occurring during pericenter passage. In my dissertation, I build upon these models using a series of grid-based radiative hydrodynamic simulations, including the effects of both ionizing ultraviolet light from existing stars as well as X-ray radiation emanating from the central black hole. Radiation is treated with an adaptive ray-tracing routine, including appropriate heating and cooling for both neutral and ionized gas. These models show that ultraviolet radiation is sufficiently strong to heat low mass gas clouds, thus suppressing star formation from clump compression. Gas disks that form from cloud capture become sufficiently dense to provide shielding from the radiation of existing central stars, thus allowing star formation to continue. Conversely, X-rays easily penetrate and heat the potentially star forming gas. For sufficiently high radiation fields, this provides a mechanism to disrupt star formation for both scenarios considered above.

GIVETIAN–FRASNIAN BOUNDARY CONODONTS FROM KERMAN PROVINCE, CENTRAL IRAN

Directory of Open Access Journals (Sweden)

HOSSEIN GHOLAMALIAN

2013-07-01

Full Text Available The Middle - Late Devonian boundary is investigated based on twenty-two conodont species and subspecies from three sections in the north and west of Kerman, southeastern central Iran. Upper Givetian - lower Frasnian carbonates of the basal part of the Bahram Formation transgressively overlie the sandstone beds of the top of (? Early - Middle Devonian Padeha Formation. These massive skeletal limestones encompass the G-F boundary. The base of Frasnian is identified by the appearance of early forms of Ancyrodella rotundiloba . It helps to compare our biozones to those of global stratotype in southern France. A new species, Polygnathus hojedki n. sp. is described here. New range is suggested for P. praepolitus .

Web Accessibility Issues for Higher & Further Education. EDNER (Formative Evaluation of the Distributed National Electronic Resource) Project. Issues Paper.

Science.gov (United States)

Manchester Metropolitan Univ. (England).

This issues paper, sixth in a series of eight, is intended to distill formative evaluation questions on topics that are central to the development of the higher and further education information environment in the United Kingdom. In undertaking formative evaluation studies, the Formative Evaluation of the Distributed National Electronic Resource…

The role of religion in the formation of cross-community relationships

Directory of Open Access Journals (Sweden)

Sadia Kidwai

2014-11-01

Full Text Available Spiritual life is a priority in many conflict-affected communities, perhaps especially in situations of displacement. It is rarely prioritised by aid agencies, yet may be central to the formation and maintaining of strong and effective cross-community relationships.

Secondary organic aerosol formation from ambient air in an oxidation flow reactor in central Amazonia

Directory of Open Access Journals (Sweden)

B. B. Palm

2018-01-01

Full Text Available Secondary organic aerosol (SOA formation from ambient air was studied using an oxidation flow reactor (OFR coupled to an aerosol mass spectrometer (AMS during both the wet and dry seasons at the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5 field campaign. Measurements were made at two sites downwind of the city of Manaus, Brazil. Ambient air was oxidized in the OFR using variable concentrations of either OH or O3, over ranges from hours to days (O3 or weeks (OH of equivalent atmospheric aging. The amount of SOA formed in the OFR ranged from 0 to as much as 10 µg m−3, depending on the amount of SOA precursor gases in ambient air. Typically, more SOA was formed during nighttime than daytime, and more from OH than from O3 oxidation. SOA yields of individual organic precursors under OFR conditions were measured by standard addition into ambient air and were confirmed to be consistent with published environmental chamber-derived SOA yields. Positive matrix factorization of organic aerosol (OA after OH oxidation showed formation of typical oxidized OA factors and a loss of primary OA factors as OH aging increased. After OH oxidation in the OFR, the hygroscopicity of the OA increased with increasing elemental O : C up to O : C ∼ 1.0, and then decreased as O : C increased further. Possible reasons for this decrease are discussed. The measured SOA formation was compared to the amount predicted from the concentrations of measured ambient SOA precursors and their SOA yields. While measured ambient precursors were sufficient to explain the amount of SOA formed from O3, they could only explain 10–50 % of the SOA formed from OH. This is consistent with previous OFR studies, which showed that typically unmeasured semivolatile and intermediate volatility gases (that tend to lack C = C bonds are present in ambient air and can explain such additional SOA formation. To investigate the sources of the

Observer enhanced control for spin-stabilized tethered formation in earth orbit

Science.gov (United States)

Guang, Zhai; Yuyang, Li; Liang, Bin

2018-04-01

This paper addresses the issues relevant to control of spin-stabilized tethered formation in circular orbit. Due to the dynamic complexities and nonlinear perturbations, it is challenging to promote the control precision for the formation deployment and maintenance. In this work, the formation dynamics are derived with considering the spinning rate of the central body, then major attention is dedicated to develop the nonlinear disturbance observer. To achieve better control performance, the observer-enhanced controller is designed by incorporating the disturbance observer into the control loop, benefits from the disturbance compensation are demonstrated, and also, the dependences of the disturbance observer performance on some important parameters are theoretically and numerically analyzed.

Partially Decentralized Control Architectures for Satellite Formations

Science.gov (United States)

Carpenter, J. Russell; Bauer, Frank H.

2002-01-01

In a partially decentralized control architecture, more than one but less than all nodes have supervisory capability. This paper describes an approach to choosing the number of supervisors in such au architecture, based on a reliability vs. cost trade. It also considers the implications of these results for the design of navigation systems for satellite formations that could be controlled with a partially decentralized architecture. Using an assumed cost model, analytic and simulation-based results indicate that it may be cheaper to achieve a given overall system reliability with a partially decentralized architecture containing only a few supervisors, than with either fully decentralized or purely centralized architectures. Nominally, the subset of supervisors may act as centralized estimation and control nodes for corresponding subsets of the remaining subordinate nodes, and act as decentralized estimation and control peers with respect to each other. However, in the context of partially decentralized satellite formation control, the absolute positions and velocities of each spacecraft are unique, so that correlations which make estimates using only local information suboptimal only occur through common biases and process noise. Covariance and monte-carlo analysis of a simplified system show that this lack of correlation may allow simplification of the local estimators while preserving the global optimality of the maneuvers commanded by the supervisors.

Hydrothermal Alteration Promotes Humic Acid Formation in Sediments: A Case Study of the Central Indian Ocean Basin

Science.gov (United States)

Sarma, Nittala S.; Kiran, Rayaprolu; Rama Reddy, M.; Iyer, Sridhar D.; Peketi, A.; Borole, D. V.; Krishna, M. S.

2018-01-01

Anomalously high concentrations of humic-rich dissolved organic matter (DOM) in extant submarine hydrothermal vent plumes traveled far from source are increasingly being reported. This DOM, able to mobilize trace metals (e.g., Fe2+) has been hypothesized as originating from organic matter produced by thermogenic bacteria. To eliminate a possible abiogenic origin of this DOM, study is required of well-preserved organic compounds that can be attributed to thermogenic bacteria. The Central Indian Ocean Basin (CIOB) is part of a diffuse plate boundary and an intraplate deformation zone. Coarse fraction (>63 µ) characteristics, mineralogy, magnetic susceptibility, and geochemistry were examined in sediments of a core raised close to a north-south fracture zone near the Equator. Two horizons of distinctly brown-colored sediments were shown as hydrothermally altered from their charred fragments and geochemistry (CaCO3, Corg, Ti/Al, Al/(Al + Fe + Mn), Sr/Ba, Mg/Li, Mn micronodules, Fe/Mn). We examined whether humic substances were preserved in these sediments, and if so whether their carbon isotope distribution would support their hydrothermal origin. Alkali extraction of sediments afforded humic acids (HA) in yields up to 1.2% in the brown sediments. The remaining portions of the core had nil or low concentrations of HA. The carbon of hydrothermal HA is isotopically heavier (average δ13C, ˜ -16.3‰) compared to nonhydrothermal HA (-18.1‰), suggesting that they were probably formed from organic matter that remained after elimination of lighter carbon enriched functional groups during diagenesis. The results provide compelling evidence of HA formation from lipids originating from thermogenic bacteria.

Depositional environments of Late Triassic lake, east-central New Mexico

Energy Technology Data Exchange (ETDEWEB)

Hester, P.M. (Bureau of Land Management, Albuquerque, NM (USA))

1989-09-01

The Redonda Member of the Chinle Formation represents deposition in a large, polymictic lake during the Late Triassic (Norian) in east-central New Mexico. This study documents and defines an extensive lacustrine system situated in western Pangaea which was influenced by both tectonic and climatic events. Areal extent of the lake may have been as much as 5,000 km{sup 2}.

Swarm formation control utilizing elliptical surfaces and limiting functions.

Science.gov (United States)

Barnes, Laura E; Fields, Mary Anne; Valavanis, Kimon P

2009-12-01

In this paper, we present a strategy for organizing swarms of unmanned vehicles into a formation by utilizing artificial potential fields that were generated from normal and sigmoid functions. These functions construct the surface on which swarm members travel, controlling the overall swarm geometry and the individual member spacing. Nonlinear limiting functions are defined to provide tighter swarm control by modifying and adjusting a set of control variables that force the swarm to behave according to set constraints, formation, and member spacing. The artificial potential functions and limiting functions are combined to control swarm formation, orientation, and swarm movement as a whole. Parameters are chosen based on desired formation and user-defined constraints. This approach is computationally efficient and scales well to different swarm sizes, to heterogeneous systems, and to both centralized and decentralized swarm models. Simulation results are presented for a swarm of 10 and 40 robots that follow circle, ellipse, and wedge formations. Experimental results are included to demonstrate the applicability of the approach on a swarm of four custom-built unmanned ground vehicles (UGVs).

Assessment of undiscovered continuous oil and gas resources in the Heath Formation, central Montana and western North Dakota, 2016

Science.gov (United States)

Drake, Ronald M.; Schenk, Christopher J.; Klett, Timothy R.; Le, Phuong A.; Leathers, Heidi M.; Brownfield, Michael E.; Finn, Thomas M.; Gaswirth, Stephanie B.; Marra, Kristen R.; Tennyson, Marilyn E.

2017-06-07

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 884 million barrels of oil and 106 billion cubic feet of gas in the North-Central Montana and Williston Basin Provinces of central Montana and western North Dakota.

Topography and distribution of central graben in Okinawa Trough Miyoko Section

Science.gov (United States)

Luan, X.; Qin, Y.

2006-05-01

and has effect on the topography and distribution of central graben. The topography and distribution of central graben we show in this paper is simile with that of low spreading mid-ocean ridge, but the shallow graben depth and overlap graben indicate that they are simile with the fastest end of low spreading mid-ocean ridge. Based on the shallow central graben and high topography of Laixi, Jimo and Pingdu Segments and the development of overlap graben, we believe that those segment are simile with fast spreading axis high, and probably are places where magma is developing. None of transform faults is found in this section, but we believe that in the low spreading cases, when there is short of magma supply, it is reasonable that the formation of new oceanic crust took the form of volcanism. So, this paper pointed out that the volcanism within the central graben is a form of new crust formation, and sea floor spreading is on going along the central graben of Okinawa Trough.

Paleocene coal deposits of the Wilcox group, central Texas

Science.gov (United States)

Hook, Robert W.; Warwick, Peter D.; SanFilipo, John R.; Schultz, Adam C.; Nichols, Douglas J.; Swanson, Sharon M.; Warwick, Peter D.; Karlsen, Alexander K.; Merrill, Matthew D.; Valentine, Brett J.

2011-01-01

Coal deposits in the Wilcox Group of central Texas have been regarded as the richest coal resources in the Gulf Coastal Plain. Although minable coal beds appear to be less numerous and generally higher in sulfur content (1 percent average, as-received basis; table 1) than Wilcox coal deposits in the Northeast Texas and Louisiana Sabine assessment areas (0.5 and 0.6 percent sulfur, respectively; table 1), net coal thickness in coal zones in central Texas is up to 32 ft thick and more persistent along strike (up to 15 mi) at or near the surface than coals of any other Gulf Coast assessment area. The rank of the coal beds in central Texas is generally lignite (table 1), but some coal ranks as great as subbituminous C have been reported (Mukhopadhyay, 1989). The outcrop of the Wilcox Group in central Texas strikes northeast, extends for approximately 140 mi between the Trinity and Colorado Rivers, and covers parts of Bastrop, Falls, Freestone, Lee, Leon, Limestone, Milam, Navarro, Robertson, and Williamson Counties (Figure 1). Three formations, in ascending order, the Hooper, Simsboro, and Calvert Bluff, are recognized in central Texas (Figure 2). The Wilcox Group is underlain conformably by the Midway Group, a mudstone-dominated marine sequence, and is overlain and scoured locally by the Carrizo Sand, a fluvial unit at the base of the Claiborne Group.

Structural, stratigraphic and hydrodynamic analysis of the Paleozoic section of central New York State

International Nuclear Information System (INIS)

Willette, P.D.

1979-01-01

A structural, stratigraphic and hydrodynamic analysis of 12 formations in central New York State between longitudes 75 30' and 78 30' is presented in the form of structure, isopach and potentiometric-fluid flow maps. Information used in the study was obtained from 2804 wells drilled for gas and oil. New concepts, approaches or reinterpretations of ideas presented in previous studies include: evidence of Taconic orogenic features as far west as Rochester, structural control of Trenton gas fields, a new interpretation of Oriskany erosional features and Onondaga reef trends, and structurally controlled fluid-flow patterns. Because fluid flow is toward the water supply of major population centers and because of the likelihood of drilling for natural gas in the area, the Salina Formation in central New York State is not a good site for a high level radioactive waste repository

Rap1 integrates tissue polarity, lumen formation, and tumorigenicpotential in human breast epithelial cells

Energy Technology Data Exchange (ETDEWEB)

Itoh, Masahiko; Nelson, Celeste M.; Myers, Connie A.; Bissell,Mina J.

2006-09-29

Maintenance of apico-basal polarity in normal breast epithelial acini requires a balance between cell proliferation, cell death, and proper cell-cell and cell-extracellular matrix signaling. Aberrations in any of these processes can disrupt tissue architecture and initiate tumor formation. Here we show that the small GTPase Rap1 is a crucial element in organizing acinar structure and inducing lumen formation. Rap1 activity in malignant HMT-3522 T4-2 cells is appreciably higher than in S1 cells, their non-malignant counterparts. Expression of dominant-negative Rap1 resulted in phenotypic reversion of T4-2 cells, led to formation of acinar structures with correct apico-basal polarity, and dramatically reduced tumor incidence despite the persistence of genomic abnormalities. The resulting acini contained prominent central lumina not observed when other reverting agents were used. Conversely, expression of dominant-active Rap1 in T4-2 cells inhibited phenotypic reversion and led to increased invasiveness and tumorigenicity. Thus, Rap1 acts as a central regulator of breast architecture, with normal levels of activation instructing apical polarity during acinar morphogenesis, and increased activation inducing tumor formation and progression to malignancy.

BioMart Central Portal: an open database network for the biological community

Science.gov (United States)

Guberman, Jonathan M.; Ai, J.; Arnaiz, O.; Baran, Joachim; Blake, Andrew; Baldock, Richard; Chelala, Claude; Croft, David; Cros, Anthony; Cutts, Rosalind J.; Di Génova, A.; Forbes, Simon; Fujisawa, T.; Gadaleta, E.; Goodstein, D. M.; Gundem, Gunes; Haggarty, Bernard; Haider, Syed; Hall, Matthew; Harris, Todd; Haw, Robin; Hu, S.; Hubbard, Simon; Hsu, Jack; Iyer, Vivek; Jones, Philip; Katayama, Toshiaki; Kinsella, R.; Kong, Lei; Lawson, Daniel; Liang, Yong; Lopez-Bigas, Nuria; Luo, J.; Lush, Michael; Mason, Jeremy; Moreews, Francois; Ndegwa, Nelson; Oakley, Darren; Perez-Llamas, Christian; Primig, Michael; Rivkin, Elena; Rosanoff, S.; Shepherd, Rebecca; Simon, Reinhard; Skarnes, B.; Smedley, Damian; Sperling, Linda; Spooner, William; Stevenson, Peter; Stone, Kevin; Teague, J.; Wang, Jun; Wang, Jianxin; Whitty, Brett; Wong, D. T.; Wong-Erasmus, Marie; Yao, L.; Youens-Clark, Ken; Yung, Christina; Zhang, Junjun; Kasprzyk, Arek

2011-01-01

BioMart Central Portal is a first of its kind, community-driven effort to provide unified access to dozens of biological databases spanning genomics, proteomics, model organisms, cancer data, ontology information and more. Anybody can contribute an independently maintained resource to the Central Portal, allowing it to be exposed to and shared with the research community, and linking it with the other resources in the portal. Users can take advantage of the common interface to quickly utilize different sources without learning a new system for each. The system also simplifies cross-database searches that might otherwise require several complicated steps. Several integrated tools streamline common tasks, such as converting between ID formats and retrieving sequences. The combination of a wide variety of databases, an easy-to-use interface, robust programmatic access and the array of tools make Central Portal a one-stop shop for biological data querying. Here, we describe the structure of Central Portal and show example queries to demonstrate its capabilities. Database URL: http://central.biomart.org. PMID:21930507

Temperature distribution, porosity migration and formation of the central void in cylindrical fuel rods

International Nuclear Information System (INIS)

Cotta, R.M.; Roberty, N.C.

1982-01-01

The porosity - and temperature distribution in cylindrical fuels rods, were studied by numerical resolution of mass-and energy equation, as well as determining the evolution of the central void radii. The finite difference method with implicit formulation for heat conduction equation and explicit formulation for continuity equation, was used. The Nichols model was used in the determination of the constitutive equation of the porous migration velocity. (E.G.) [pt

Comparative ecobalancing accounting of semi-central house heat supply from wood residues

International Nuclear Information System (INIS)

Biemann, Kirsten

2015-01-01

impact. Heat demanders and network structure vary for the different settlement types. This impacts the heat losses and the amount of energy generated from wood in the network. Combined heat and power plants promise higher fuel utilization. They decrease costs and environmental impacts. The heat losses in the network vary greatly between 23 percent for small single-family houses and 4 percent for big multi-family buildings. Therefore networks with bigger heat demanders have lower environmental burdens. From an economic point of view the conversion from a gas heater to the connection of a multi- family building to a semi- centralized heating network using wood residues as fuel is worthwhile. However for a single-family building this is often not the case. A comparison between the semi- centralized heat supply from wood residues and the commonly used heat supply from gas heaters shows a large potential to decrease greenhouse gas emissions, ozone depletion and fossil resource usage when using the first variant. However, it increases particulate matter formation, photochemical oxidant formation, eutrophication, and acidification. Only the usage of a wood gasification and a combined heat and power plant decreases particulate matter formation slightly. Similar results were obtained for a centralized heating network using wood residues as fuel. Using wood heaters in the buildings further decreases greenhouse gas emissions, ozone depletion and fossil resources, but results in an increased particulate matter formation. This particulate matter formation is over 1.000 percent bigger than for gas heaters.

Paleomagnetic data for Siberia and Baltica in the context of testing some geodynamic models of the formation of the Central Asian Mobile Belt

Science.gov (United States)

Shatsillo, A. V.; Kuznetsov, N. B.; Dronov, A. V.

2017-09-01

The synthesis of the paleomagnetic data for the Siberian (Siberia) and East European (Baltica) platforms shows that since the Early Paleozoic they could have experienced coherent movements as a part of consolidated continental agglomeration (a composite continent), which also includes the Arctida continent. Based on the paleomagnetic data, the relative positions of the Siberia and Baltica during the Ordovician is reconstructed, and a series of paleogeographical reconstructions describing the drift of the composite continent is suggested. The results of the lithologic-facial analysis of the sedimentation settings within the Ordovician basins of the Siberian and East European platforms and paleoclimatic markers are consistent with the suggested configuration and paleogeographical position of the composite continent. The suggested reconstructions and the ages of detrital zircons from the Early Paleozoic complexes of the platform margins and some objects of the Central Asian Mobile Belt (CAMB) reasonably well agree with the hypothesis (Sengör et al., 1993) which interprets the formation of the structure of CAMB Paleozoides as a result of the evolution of the island arc stretching along the margins of Siberia and Baltica.

Geology and ground water in north-central Santa Cruz County, California

Science.gov (United States)

Johnson, Michael J.

1980-01-01

North-central Santa Cruz County is underlain mainly by folded sedimentary rocks of Tertiary and Cretaceous age that have been highly fractured by movements in the San Andreas fault system. Ground water is stored in fractures within shale and mudstone formations and in intergranular pore spaces within fine- to very fine-grained sandstone and siltstone formations. Fewer than 10% of the wells yield more than 15 gallons of water per minute. The water in most wells is moderately hard to very hard, is generally of a sodium bicarbonate or calcium bicarbonate type, and commonly has excessive concentrations of iron or manganese. Of the many geologic units in the study area, only the Purisima Formation of Pliocene age has the potential to sustain well yields greater than 100 gallons per minute. (USGS)

STAR FORMATION IN PARTIALLY GAS-DEPLETED SPIRAL GALAXIES

International Nuclear Information System (INIS)

Rose, James A.; Miner, Jesse; Levy, Lorenza; Robertson, Paul

2010-01-01

Broadband B and R and Hα images have been obtained with the 4.1 m SOAR telescope atop Cerro Pachon, Chile, for 29 spiral galaxies in the Pegasus I galaxy cluster and for 18 spirals in non-cluster environments. Pegasus I is a spiral-rich cluster with a low-density intracluster medium and a low galaxy velocity dispersion. When combined with neutral hydrogen (H I) data obtained with the Arecibo 305 m radio telescope, acquired by Levy et al. (2007) and by Springob et al. (2005b), we study the star formation rates in disk galaxies as a function of their H I deficiency. To quantify H I deficiency, we use the usual logarithmic deficiency parameter, DEF. The specific star formation rate (SSFR) is quantified by the logarithmic flux ratio of Hα flux to R-band flux, and thus roughly characterizes the logarithmic SFR per unit stellar mass. We find a clear correlation between the global SFR per unit stellar mass and DEF, such that the SFR is lower in more H I-deficient galaxies. This correlation appears to extend from the most gas-rich to the most gas-poor galaxies. We also find a correlation between the central SFR per unit mass relative to the global values, in the sense that the more H I-deficient galaxies have a higher central SFR per unit mass relative to their global SFR values than do gas-rich galaxies. In fact, approximately half of the H I-depleted galaxies have highly elevated SSFRs in their central regions, indicative of a transient evolutionary state. In addition, we find a correlation between gas depletion and the size of the Hα disk (relative to the R-band disk); H I-poor galaxies have truncated disks. Moreover, aside from the elevated central SSFR in many gas-poor spirals, the SSFR is otherwise lower in the Hα disks of gas-poor galaxies than in gas-rich spirals. Thus, both disk truncation and lowered SSFR levels within the star-forming part of the disks (aside from the enhanced nuclear SSFR) correlate with H I deficiency, and both phenomena are found to

Why is the radial flow in central pA collisions stronger than in AA?

International Nuclear Information System (INIS)

Kalaydzhyan, Tigran; Shuryak, Edward

2014-01-01

Both the transverse size and entropy density per area in central pA collisions is smaller than in central AA, and yet the radial flow is stronger. We propose an explanation to this puzzle. Using a weak attraction between strings through the σ-meson exchange, fitted to the lattice data, we find collective implosion of the “spaghetti” multi-string state. Collectivization of the sigma field of the strings is the QCD analog of the black hole formation occurring in holographic models

Central and peripheral interactions of hadrons

Energy Technology Data Exchange (ETDEWEB)

Dremin, I.M. [Lebedev Physics Institute, Moscow (Russian Federation); National Research Nuclear University ' ' MEPhI' ' , Moscow (Russian Federation); Nechitailo, V.A. [Lebedev Physics Institute, Moscow (Russian Federation); White, S.N. [CERN, Geneva (Switzerland)

2017-12-15

Surprisingly enough, the ratio of elastic to inelastic cross sections of proton interactions increases with energy in the interval corresponding to ISR→LHC (i.e. from 10 to 10{sup 4} GeV). That leads to special features of their spatial interaction region at these and higher energies. Within the framework of some phenomenological models, we show how the particular ranges of the transferred momenta measured in elastic scattering experiments expose the spatial features of the inelastic interaction region according to the unitarity condition. The difference between their predictions at higher energies is discussed. The notion of central and peripheral collisions of hadrons is treated in terms of the impact-parameter description. It is shown that the shape of the differential cross section in the diffraction cone is mostly determined by collisions with intermediate impact parameters. Elastic scattering at very small transferred momenta is sensitive to peripheral processes with large impact parameters. The role of central collisions in the formation of the diffraction cone is less significant. (orig.)

The storm time central plasma sheet

Directory of Open Access Journals (Sweden)

R. Schödel

2002-11-01

Full Text Available The plasma sheet plays a key role during magnetic storms because it is the bottleneck through which large amounts of magnetic flux that have been eroded from the dayside magnetopause have to be returned to the dayside magnetosphere. Using about five years of Geotail data we studied the average properties of the near- and midtail central plasma sheet (CPS in the 10–30 RE range during magnetic storms. The earthward flux transport rate is greatly enhanced during the storm main phase, but shows a significant earthward decrease. Hence, since the magnetic flux cannot be circulated at a sufficient rate, this leads to an average dipolarization of the central plasma sheet. An increase of the specific entropy of the CPS ion population by a factor of about two during the storm main phase provides evidence for nonadiabatic heating processes. The direction of flux transport during the main phase is consistent with the possible formation of a near-Earth neutral line beyond ~20 RE.Key words. Magnetospheric physics (plasma convection; plasma sheet; storms and substorms

Sequence stratigraphy, sedimentary systems and petroleum plays in a low-accommodation basin: Middle to upper members of the Lower Jurassic Sangonghe Formation, Central Junggar Basin, Northwestern China

Science.gov (United States)

Feng, Youliang; Jiang, Shu; Wang, Chunfang

2015-06-01

The Lower Jurassic Junggar Basin is a low-accommodation basin in northwestern China. Because of low subsidence rates and a warm, wet climate, deposits of the Central subbasin of the Junggar Basin formed from fluvial, deltaic, shallow lake facies. Sequence stratigraphy and sedimentary systems of the Lower Jurassic members of the Sangonghe Formation (J1s) were evaluated by observing cores, interpreting wireline logs and examining seismic profiles. Two third-order sequences were recognized in the strata. The distribution of the sedimentary systems in the systems tracts shows that tectonic movement, paleorelief, paleoclimate and changes in lake level controlled the architecture of individual sequences. During the development of the lowstand systems tract (LST), the intense structural movement of the basin resulted in a significant fall in the water level in the lake, accompanied by rapid accommodation decrease. Braided rivers and their deltaic systems were also developed in the Central Junggar Basin. Sediments carried by braided rivers were deposited on upward slopes of the paleorelief, and braid-delta fronts were deposited on downward slopes. During the transgressive systems tract (TST), the tectonic movement of the basin was quiescent and the climate was warm and humid. Lake levels rose and accommodation increased quickly, shoal lines moved landward, and shore- to shallow-lake deposits, sublacustrine fans and deep-lake facies were deposited in shallow- to deep-lake environments. During the highstand systems tract (HST), the accommodation no longer increased but sediment supply continued, far exceeding accommodation. HST deposits slowly formed in shallow-lake to meandering river delta-front environments. Relatively low rates of structural subsidence and low accommodation resulted in coarse-grained successions that were fining upward. Deposits were controlled by structural movement and paleorelief within the LST to TST deposits in the Central subbasin. Fine- to medium

Method and apparatus for production of subsea hydrocarbon formations

Energy Technology Data Exchange (ETDEWEB)

Bladford, J.

1996-07-18

A system for controlling, separating, processing and exporting well fluids produced from subsea hydrocarbon formations is disclosed. The subsea well tender system includes a surface buoy supporting one or more decks above the water surface for accommodating equipment to process oil, gas and water recovered from the subsea hydrocarbon formation. The surface buoy includes a surface-piercing central flotation column connected to one or more external flotation tanks located below the water surface. The surface buoy is secured to the seabed by one or more tendons which are anchored to a foundation with piles imbedded in the seabed. The system accommodates multiple versions on the surface buoy configuration. (author) figs.

P-MaNGA: GRADIENTS IN RECENT STAR FORMATION HISTORIES AS DIAGNOSTICS FOR GALAXY GROWTH AND DEATH

International Nuclear Information System (INIS)

Li, Cheng; Wang, Enci; Lin, Lin; Xiao, Ting; Bershady, Matthew A.; Tremonti, Christy A.; Bundy, Kevin; Cheung, Edmond; Yan, Renbin; Bizyaev, Dmitry; Blanton, Michael; Gelfand, Joseph; Cales, Sabrina; Cherinka, Brian; Law, David R.; Drory, Niv; Emsellem, Eric; Fu, Hai; Lin, Lihwai; MacDonald, Nick

2015-01-01

We present an analysis of the data produced by the MaNGA prototype run (P-MaNGA), aiming to test how the radial gradients in recent star formation histories, as indicated by the 4000 Å break (D n (4000)), Hδ absorption (EW(Hδ A )), and Hα emission (EW(Hα)) indices, can be useful for understanding disk growth and star formation cessation in local galaxies. We classify 12 galaxies observed on two P-MaNGA plates as either centrally quiescent (CQ) or centrally star-forming (CSF), according to whether D n (4000) measured in the central spaxel of each datacube exceeds 1.6. For each spaxel we generate both 2D maps and radial profiles of D n (4000), EW(Hδ A ), and EW(Hα). We find that CSF galaxies generally show very weak or no radial variation in these diagnostics. In contrast, CQ galaxies present significant radial gradients, in the sense that D n (4000) decreases, while both EW(Hδ A ) and EW(Hα) increase from the galactic center outward. The outer regions of the galaxies show greater scatter on diagrams relating the three parameters than their central parts. In particular, the clear separation between centrally measured quiescent and star-forming galaxies in these diagnostic planes is largely filled in by the outer parts of galaxies whose global colors place them in the green valley, supporting the idea that the green valley represents a transition between blue-cloud and red-sequence phases, at least in our small sample. These results are consistent with a picture in which the cessation of star formation propagates from the center of a galaxy outward as it moves to the red sequence

A New Model of Black Hole Formation

Directory of Open Access Journals (Sweden)

Thayer G. D.

2013-10-01

Full Text Available The formation of a black hole and its event horizon are described. Conclusions, which are the result of a thought experiment, show that Schwarzschild [1] was correct: A singularity develops at the event horizon of a newly-formed black hole. The intense gravitational field that forms near the event horizon results in the mass-energy of the black hole accumulating in a layer just inside the event horizon, rather than collapsing into a central singularity.

Foraminiferal and radiolarian biostratigraphy of the youngest (Late Albian through Late Cenomanian) sediments of the Tatra massif, Central Western Carpathians

Science.gov (United States)

Bąk, Krzysztof; Bąk, Marta

2013-06-01

Bąk, K. and Bąk M. 2013. Foraminiferal and radiolarian biostratigraphy of the youngest (Late Albian through Late Cenomanian) sediments of the Tatra massif, Central Western Carpathians. Acta Geologica Polonica, 63 (2), 223-237. Warszawa. The foraminiferal and radiolarian biostratigraphy of selected sections of the Zabijak Formation, the youngest sediments of the Tatra massif (Central Western Carpathians), have been studied. Benthic foraminifers, mainly agglutinated species, occur abundantly and continuously throughout the studied succession, while planktic foraminifers are generally sparse. Five planktic and two benthic foraminiferal zones have been recognized. The marly part of the Zabijak Formation comprises the Pseudothalmanninella ticinensis (Upper Albian) through the Rotalipora cushmani (Upper Cenomanian) planktic foraminiferal zones, and the Haplophragmoides nonioninoides and Bulbobaculites problematicus benthic foraminiferal zones. The radiolarians were recognized exclusively in the Lower Cenomanian part of the formation.

Formation of the City of Belém (PA: Central Area and its Paper Historical and Geographical

Directory of Open Access Journals (Sweden)

Antônio Carlos Ribeiro Araújo Júnior

2012-12-01

Full Text Available In the 17th Century the urban life of Belém spread out from a promontorylocated at the meeting point of Guajará Bay and Guamá River. These "natural obstacles" (waterways, floodplains and flooded forest presented momentary setbacks to urban expansion. Overcoming these obstacles the city of Belém developed a central area characerized by change and continuity. By identifying and analyzing historical and geographical changes in the central area of Belém a better understanding can be obtained of new functions and features of urban space in Belém today.

Assessment of central dopaminergic function using plasma-free homovanillic acid after debrisoquin administration.

Science.gov (United States)

Riddle, M A; Leckman, J F; Cohen, D J; Anderson, M; Ort, S I; Caruso, K A; Shaywitz, B A

1986-01-01

Central dopaminergic (DA) function in children and adults was assessed by monitoring plasma-free levels of the dopamine metabolite homovanillic acid (pHVA) before and after a single oral dose and chronic oral administration of debrisoquin. Debrisoquin inhibits peripheral metabolism of dopamine to HVA and does not cross the blood-brain barrier. By reducing peripheral formation of HVA through the use of debrisoquin, the remaining HVA in plasma more accurately reflects central DA activity. Debrisoquin administration resulted in marked reductions of pHVA in each of 12 patients studied. Eleven of the 12 subjects tolerated debrisoquin without physical or behavioral side effects. The debrisoquin administration method appears to be a safe and potentially valid technique for evaluating aspects of central dopaminergic function in children and adults.

Potential formation in axisymmetrized tandem mirror GAMMA 10

International Nuclear Information System (INIS)

Cho, T.; Ichimura, M.; Inutake, M.

1985-01-01

The paper reports experimental results on potential formation and end plugging in the axisymmetrized tandem mirror GAMMA 10. The plugging at both ends has been achieved by a combination of neutral beams and gyrotrons. The presence of a plug potential with a thermal barrier in an axisymmetric mirror has been confirmed by direct measurement of the axial potential profile. Enhancement of axial particle confinement has been observed during the end plugging. Non-ambipolar radial transport has been greatly reduced in the axisymmetrized magnetic configuration. The potentials measured by beam probes and end loss analysers are 0.7, 0.4 and 1.1 kV in the central, barrier and plug regions, respectively. Strong end plugging is observed when the central-cell density is higher than the densities in the plug and the barrier, and the plug density remains higher than the barrier density. The plug electron temperature is higher than the central temperature. Hot electrons forming a football-shaped profile have been stably produced in the axisymmetric mirror. The beta value and the fraction of the hot electrons reach up to 5% and 0.8, respectively. Central-cell ion-cyclotron resonance heating can sustain a stable plasma with higher density and ion temperature when resonance surfaces exist in both the anchor and the central cells. (author)

Rheomorphic ignimbrites of the Rogerson Formation, central Snake River plain, USA

DEFF Research Database (Denmark)

Knott, Thomas R.; Reichow, Marc K.; Branney, Michael J.

2016-01-01

Rogerson Graben, USA, is critically placed at the intersection between the Yellowstone hotspot track and the southern projection of the west Snake River rift. Eleven rhyolitic members of the re-defined, ≥420-m-thick, Rogerson Formation record voluminous high-temperature explosive eruptions....... Between 11.9 and ∼8 Ma, the average frequency of large explosive eruptions in this region was 1 per 354 ky, about twice that at Yellowstone. The chemistry and mineralogy of the early rhyolites show increasing maturity with time possibly by progressive fractional crystallisation. This was followed......-margin monocline, which developed between 10.59 and 8 Ma. The syn-volcanic basin topography contrasted significantly with the present-day elevated Yellowstone hotspot plateau. Concurrent basin-and-range extension produced the N-trending Rogerson Graben: early uplift of the Shoshone Hills (≥10.34 Ma) was followed...

Dew formation on the surface of biological soil crusts in central European sand ecosystems

Directory of Open Access Journals (Sweden)

T. Fischer

2012-11-01

Full Text Available Dew formation was investigated in three developmental stages of biological soil crusts (BSC, which were collected along a catena of an inland dune and in the initial substrate. The Penman equation, which was developed for saturated surfaces, was modified for unsaturated surfaces and used for prediction of dewfall rates. The levels of surface saturation required for this approach were predicted using the water retention functions and the thicknesses of the BSCs. During a first field campaign (2–3 August 2011, dewfall increased from 0.042 kg m⁻² for the initial sandy substrate to 0.058, 0.143 and 0.178 kg m⁻² for crusts 1 to 3, respectively. During a second field campaign (17–18 August 2011, where dew formation was recorded in 1.5 to 2.75-h intervals after installation at 21:30 CEST, dewfall increased from 0.011 kg m⁻² for the initial sandy substrate to 0.013, 0.028 and 0.055 kg m⁻² for crusts 1 to 3, respectively. Dewfall rates remained on low levels for the substrate and for crust 1, and decreased overnight for crusts 2 and 3 (with crust 3 > crust 2 > crust 1 throughout the campaign. Dew formation was well reflected by the model response. The suggested mechanism of dew formation involves a delay in water saturation in near-surface soil pores and extracellular polymeric substances (EPS where the crusts were thicker and where the water capacity was high, resulting in elevated vapor flux towards the surface. The results also indicate that the amount of dewfall was too low to saturate the BSCs and to observe water flow into deeper soil. Analysis of the soil water retention curves revealed that, despite the sandy mineral matrix, moist crusts clogged by swollen EPS pores exhibited a clay-like behavior. It is hypothesized that BSCs gain double benefit from suppressing their competitors by runoff generation and from improving their water supply by dew collection. Despite higher amounts of dew, the

SDSS-IV MaNGA - the spatially resolved transition from star formation to quiescence

Science.gov (United States)

Belfiore, Francesco; Maiolino, Roberto; Maraston, Claudia; Emsellem, Eric; Bershady, Matthew A.; Masters, Karen L.; Bizyaev, Dmitry; Boquien, Médéric; Brownstein, Joel R.; Bundy, Kevin; Diamond-Stanic, Aleksandar M.; Drory, Niv; Heckman, Timothy M.; Law, David R.; Malanushenko, Olena; Oravetz, Audrey; Pan, Kaike; Roman-Lopes, Alexandre; Thomas, Daniel; Weijmans, Anne-Marie; Westfall, Kyle B.; Yan, Renbin

2017-04-01

Using spatially resolved spectroscopy from SDSS-IV MaNGA we have demonstrated that low ionization emission-line regions (LIERs) in local galaxies result from photoionization by hot evolved stars, not active galactic nuclei, hence tracing galactic region hosting old stellar population where, despite the presence of ionized gas, star formation is no longer occurring. LIERs are ubiquitous in both quiescent galaxies and in the central regions of galaxies where star formation takes place at larger radii. We refer to these two classes of galaxies as extended LIER (eLIER) and central LIER (cLIER) galaxies, respectively. cLIERs are late-type galaxies primarily spread across the green valley, in the transition region between the star formation main sequence and quiescent galaxies. These galaxies display regular disc rotation in both stars and gas, although featuring a higher central stellar velocity dispersion than star-forming galaxies of the same mass. cLIERs are consistent with being slowly quenched inside-out; the transformation is associated with massive bulges, pointing towards the importance of bulge growth via secular evolution. eLIERs are morphologically early types and are indistinguishable from passive galaxies devoid of line emission in terms of their stellar populations, morphology and central stellar velocity dispersion. Ionized gas in eLIERs shows both disturbed and disc-like kinematics. When a large-scale flow/rotation is observed in the gas, it is often misaligned relative to the stellar component. These features indicate that eLIERs are passive galaxies harbouring a residual cold gas component, acquired mostly via external accretion. Importantly, quiescent galaxies devoid of line emission reside in denser environments and have significantly higher satellite fraction than eLIERs. Environmental effects thus represent the likely cause for the existence of line-less galaxies on the red sequence.

Comparison of Atmospheric New Particle Formation Events Events in Three Central European Cities.

Czech Academy of Sciences Publication Activity Database

Németh, Z.; Rosati, B.; Zíková, Naděžda; Salma, I.; Bozó, L.; Dameto de España, C.; Schwarz, Jaroslav; Ždímal, Vladimír; Wonaschütz, A.

2018-01-01

Roč. 178, APR 2018 (2018), s. 191-197 ISSN 1352-2310 R&D Projects: GA MŠk(CZ) LM2015037 EU Projects: European Commission(XE) 654109 - ACTRIS-2 Grant - others:HSRFK(HU) K116788; HSRFK(HU) PD124283; NRDIO(HU) GINOP-2.3.2-15-2016-00055 Institutional support: RVO:67985858 Keywords : urban environment * ultrafine particles * new particle formation Subject RIV: DG - Athmosphere Sciences, Meteorology OBOR OECD: Meteorology and atmospheric sciences Impact factor: 3.629, year: 2016

New Discoveries in Planetary Systems and Star Formation through Advances in Laboratory Astrophysics

OpenAIRE

WGLA, AAS; Brickhouse, Nancy; Cowan, John; Drake, Paul; Federman, Steven; Ferland, Gary; Frank, Adam; Herbst, Eric; Olive, Keith; Salama, Farid; Savin, Daniel Wolf; Ziurys, Lucy

2009-01-01

As the panel on Planetary Systems and Star Formation (PSF) is fully aware, the next decade will see major advances in our understanding of these areas of research. To quote from their charge, these advances will occur in studies of solar system bodies (other than the Sun) and extrasolar planets, debris disks, exobiology, the formation of individual stars, protostellar and protoplanetary disks, molecular clouds and the cold ISM, dust, and astrochemistry. Central to the progress in these areas ...

Immunohistochemical study of sensory nerve formations in human glabrous skin.

Science.gov (United States)

Haro, J J; Vega, J A; del Valle, M E; Calzada, B; Zaccheo, D; Malinovsky, L

1991-01-01

The sensory nerve formations (or corpuscles) of normal human glabrous skin from hand and fingers, obtained by punch biopsies, were studied by the streptavidin-biotin method using monoclonal antibodies directed against neurofilament protein (NFP), S-100 protein, glial fibrillary acidic protein (GFAP), cytokeratins, and vimentin. NFP immunoreactivity (IR) was observed in the central axons of most sensory formations, while S-100 protein IR was restricted to non-neuronal cells forming the so-called inner cells core or lamellar cells. Furthermore, vimentin IR was found in the same cells of Meissner's and glomerular corpuscles. None of the sensory nerve formations were stained for GFAP or keratin. The present results suggest that the main nature of the intermediate filaments of the non-neuronal cells of sensory nerve formations from human glabrous skin is represented by vimentin and not by GFAP. Thus, our findings suggest that lamellar and inner core cells of SNF are modified and specialized Schwann cells and not epithelial or perineurial derived cells.

Analysis of the formation mechanism of the slug and jet center hole of axisymmetric shaped charges

Science.gov (United States)

Baoxiang, Ren; Gang, Tao; Peng, Wen; Changxing, Du; Chunqiao, Pang; Hongbo, Meng

2018-06-01

In the jet formation process of axisymmetric shaped charges, the slug is also formed. There is always a central hole in the symmetry axis of the jet and slug. The phenomenon was rarely mentioned and analyzed by the classical theory of shaped charges. For this problem, this paper attempts to explain the existence of the central hole in the jet and slug. Based on the analysis of recovery slug, we know that the jet and slug are in solid state in the process of formation. Through the analysis of X-flash radiographs of the stretching jet and particulation fracture, it is confirmed that the center holes in the jet are also present. Meanwhile, through the analysis of the microstructure of the recovered slug, it is found that there is a wave disturbance near the surface of the central hole. It can be speculated that the wave disturbance also exist in the jet. This effect may be one of the reasons for jet breakup. Due to the presence of the central hole in the jet, the density deficit of the jet obtained by other tests is very reasonable.

Aims and Formats of performance measurement at Danish Universities

DEFF Research Database (Denmark)

Raffnsøe-Møller, Morten

2011-01-01

Abstract This article traces the aims and formats of performance measurement of Danish Universities as they originate from the Ministry of Finance’s plan for governance of the public sector. The article further show that the fierce conflicts between central administration and the universities over...... and intelligent regimes – is used to propose a way out of the current governance impasse at the universities....

Modern beachrock formation in Durban, KwaZulu-Natal

OpenAIRE

Hayley Cawthra; Ron Uken

2012-01-01

We explored the recent cementation of modern beachrock on the seaward margin of the Durban Bluff, central KwaZulu-Natal. The low latitude and subtropical climatic setting is a unique context compared to the more commonly documented contemporary beachrock formation in the tropics. Geological field mapping was carried out and here we present results based on sedimentary facies of a clastic shoreline and carbonate diagenesis of interstitial cements using transmitted light microscopy. The beachro...

Security challenges to Central European bordering territories: view from the Transcarpatian region of Ukraine

Directory of Open Access Journals (Sweden)

Myroslava Lendel

2015-12-01

Full Text Available The factor of integral Central European space determines the formation of common challenges to the region's security. One part of them is not visualized or not perceived in the capital cities. These threats may be most vividly traced in the Transcarpathian region of Ukraine, taking into consideration the fact that it borders with the abovementioned countries. These are ethnopolitical threats, caused by the multiethnic population of the region, energy dependence, threats of social economic peripherization of Central European bordering territories, informational influence on the population, different attitudes to Ukraine-Russia conflict.

P-MaNGA: GRADIENTS IN RECENT STAR FORMATION HISTORIES AS DIAGNOSTICS FOR GALAXY GROWTH AND DEATH

Energy Technology Data Exchange (ETDEWEB)

Li, Cheng; Wang, Enci; Lin, Lin; Xiao, Ting [Partner Group of Max-Planck Institute for Astrophysics, Shanghai Astronomical Observatory, Nandan Road 80, Shanghai 200030 (China); Bershady, Matthew A.; Tremonti, Christy A. [Department of Astronomy, University of Wisconsin–Madison, Madison, WI 53706 (United States); Bundy, Kevin; Cheung, Edmond [Kavli Institute for the Physics and Mathematics of the universe (Kavli IPMU, WPI), Todai Institutes for Advanced Study, the University of Tokyo, Kashiwa 277-8583 (Japan); Yan, Renbin [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); Bizyaev, Dmitry [Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States); Blanton, Michael; Gelfand, Joseph [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Cales, Sabrina [Yale Center for Astronomy and Astrophysics, Physics Department, Yale University, P.O. Box 208120, New Haven, CT 06520-8120 (United States); Cherinka, Brian; Law, David R. [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Drory, Niv [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Emsellem, Eric [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Fu, Hai [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Lin, Lihwai [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 106, Taiwan (China); MacDonald, Nick, E-mail: leech@shao.ac.cn [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); and others

2015-05-10

We present an analysis of the data produced by the MaNGA prototype run (P-MaNGA), aiming to test how the radial gradients in recent star formation histories, as indicated by the 4000 Å break (D{sub n}(4000)), Hδ absorption (EW(Hδ{sub A})), and Hα emission (EW(Hα)) indices, can be useful for understanding disk growth and star formation cessation in local galaxies. We classify 12 galaxies observed on two P-MaNGA plates as either centrally quiescent (CQ) or centrally star-forming (CSF), according to whether D{sub n}(4000) measured in the central spaxel of each datacube exceeds 1.6. For each spaxel we generate both 2D maps and radial profiles of D{sub n}(4000), EW(Hδ{sub A}), and EW(Hα). We find that CSF galaxies generally show very weak or no radial variation in these diagnostics. In contrast, CQ galaxies present significant radial gradients, in the sense that D{sub n}(4000) decreases, while both EW(Hδ{sub A}) and EW(Hα) increase from the galactic center outward. The outer regions of the galaxies show greater scatter on diagrams relating the three parameters than their central parts. In particular, the clear separation between centrally measured quiescent and star-forming galaxies in these diagnostic planes is largely filled in by the outer parts of galaxies whose global colors place them in the green valley, supporting the idea that the green valley represents a transition between blue-cloud and red-sequence phases, at least in our small sample. These results are consistent with a picture in which the cessation of star formation propagates from the center of a galaxy outward as it moves to the red sequence.

Comparison between the fragmentation processes in central Pb + Ag and Pb + Au collisions

International Nuclear Information System (INIS)

Jouault, B.; Royer, G.; Sebille, F.; Haddad, F.; Lecolley, J.F.

1996-01-01

The fragmentation processes of a medium mass system and of a very massive one formed in central collisions are compared within the Landau-Vlasov model taking into account both the isospin dependence and the two-body residual interactions. The simulations predict the formation of a roughly ellipsoidal source in the central Pb + Ag reactions while, for the Pb + Au system, the fragmentation occurs from an hollow source, the configuration of which being intermediate between bubble-like and toroidal shapes. This difference shapes explain and allow to reproduce semi-quantitatively the two different profiles of the experimental kinetic energy spectra. (authors)

Fred Hoyle: contributions to the theory of galaxy formation

Science.gov (United States)

Efstathiou, George

I review two fundamental contributions that Fred Hoyle made to the theory of galaxy formation. Hoyle was the first to propose that protogalaxies acquired their angular momentum via tidal torques from neighbouring perturbations during a period of gravitational instability. To my knowldege, he was also the first to suggest that the masses of galaxies could be explained by the requirement that primordial gas clouds cool radiatively on a suitable timescale. Tidal torques and cooling arguments play a central role in the modern theory of galaxy formation. It is a measure of Hoyle's breadth and inventiveness that he recognized the importance of these processes at such an early stage in the history of the subject.

Uranium favorability of the San Rafael Swell area, east-central Utah

International Nuclear Information System (INIS)

Mickle, D.G.; Jones, C.A.; Gallagher, G.L.; Young, P.; Dubyk, W.S.

1977-10-01

The San Rafael Swell project area in east-central Utah is approximately 3,000 sq mi and includes the San Rafael Swell anticline and the northern part of the Waterpocket Fold monocline at Capitol Reef. Rocks in the area are predominantly sedimentary rocks of Pennsylvanian through Cretaceous age. Important deposits of uranium in the project area are restricted to two formations, the Chinle (Triassic) and Morrison (Jurassic) Formations. A third formation, the White Rim Sandstone (Permian), was also studied because of reported exploration activity. The White Rim Sandstone is considered generally unfavorable on the basis of lithologic characteristics, distance from a possible source of uranium, lack of apparent mineralization, and the scarcity of anomalies on gamma-ray logs or in rock, water, and stream-sediment samples. The lower Chinle from the Moss Back Member down to the base of the formation is favorable because it is a known producer. New areas for exploration are all subsurface. Both Salt Wash and Brushy Basin Members of the Morrison Formation are favorable. The Salt Wash Member is favorable because it is a known producer. The Brushy Basin Member is favorable as a low-grade resource

Spatially-resolved star formation histories of CALIFA galaxies. Implications for galaxy formation

Science.gov (United States)

González Delgado, R. M.; Pérez, E.; Cid Fernandes, R.; García-Benito, R.; López Fernández, R.; Vale Asari, N.; Cortijo-Ferrero, C.; de Amorim, A. L.; Lacerda, E. A. D.; Sánchez, S. F.; Lehnert, M. D.; Walcher, C. J.

2017-11-01

This paper presents the spatially resolved star formation history (SFH) of nearby galaxies with the aim of furthering our understanding of the different processes involved in the formation and evolution of galaxies. To this end, we apply the fossil record method of stellar population synthesis to a rich and diverse data set of 436 galaxies observed with integral field spectroscopy in the CALIFA survey. The sample covers a wide range of Hubble types, with stellar masses ranging from M⋆ 109 to 7 × 1011 M⊙. Spectral synthesis techniques are applied to the datacubes to retrieve the spatially resolved time evolution of the star formation rate (SFR), its intensity (ΣSFR), and other descriptors of the 2D SFH in seven bins of galaxy morphology (E, S0, Sa, Sb, Sbc, Sc, and Sd) and five bins of stellar mass. Our main results are that (a) galaxies form very fast independently of their current stellar mass, with the peak of star formation at high redshift (z > 2). Subsequent star formation is driven by M⋆ and morphology, with less massive and later type spirals showing more prolonged periods of star formation. (b) At any epoch in the past, the SFR is proportional to M⋆, with most massive galaxies having the highest absolute (but lowest specific) SFRs. (c) While today, the ΣSFR is similar for all spirals and significantly lower in early-type galaxies (ETG), in the past, the ΣSFR scales well with morphology. The central regions of today's ETGs are where the ΣSFR reached the highest values (> 103 M⊙ Gyr-1 pc-2), similar to those measured in high-redshift star-forming galaxies. (d) The evolution of ΣSFR in Sbc systems matches that of models for Milky Way-like galaxies, suggesting that the formation of a thick disk may be a common phase in spirals at early epochs. (e) The SFR and ΣSFR in outer regions of E and S0 galaxies show that they have undergone an extended phase of growth in mass between z = 2 and 0.4. The mass assembled in this phase is in agreement with

Contribution of Topological Domains and Loop Formation to 3D Chromatin Organization

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Vuthy Ea

2015-07-01

Full Text Available Recent investigations on 3D chromatin folding revealed that the eukaryote genomes are both highly compartmentalized and extremely dynamic. This review presents the most recent advances in topological domains’ organization of the eukaryote genomes and discusses the relationship to chromatin loop formation. CTCF protein appears as a central factor of these two organization levels having either a strong insulating role at TAD borders, or a weaker architectural role in chromatin loop formation. TAD borders directly impact on chromatin dynamics by restricting contacts within specific genomic portions thus confining chromatin loop formation within TADs. We discuss how sub-TAD chromatin dynamics, constrained into a recently described statistical helix conformation, can produce functional interactions by contact stabilization.

Articulating Implicit Theories of Change. EDNER (Formative Evaluation of the Distributed National Electronic Resource) Project. Issues Paper.

Science.gov (United States)

Manchester Metropolitan Univ. (England).

This issues paper, seventh in a series of eight, is intended to distill formative evaluation questions on topics that are central to the development of the higher and further education information environment in the United Kingdom. The aim of this issues paper is to provide a description of the approach of the Formative Evaluation of the…

Depositional environments of the uranium bearing Cutler Formations, Lisbon Valley, Utah

International Nuclear Information System (INIS)

Campbell, J.A.; Steele-Mallory, B.A.

1979-01-01

The Cutler Formation in Lisbon Valley, San Juan County, Utah, is composed predominantly of fluvial arkosic sandstones, siltstones, shales, and mudstones that were deposited by meandering streams that flowed across a flood plain and tidal flat close to sea level. Two types of channel deposits are recognized from their sedimentary structures: meandering and distributary. The flood plain was occasionally transgressed by a shallow sea from the west, resulting in the deposition of several thin limestones and marine sandstones. The marine sandstones were deposited as longshore bars. Wind transported sand along the shoreline of the shallow sea, forming a coastal dune field. Marine sandstones and eolian sandstones are more common in the upper Cutler in the southern part of the area, whereas in the central and northern part of the area the formation is predominantly fluvial. Crossbed orientation indicates that Cutler streams flowed S. 67 0 W. on the average, whereas marine currents moved sediment S. 36 0 E. and N. 24 0 W., and wind transported sand S. 80 0 E. The uranium in the Cutler is found in the central and northern part of the area, in the upper part of the formation, in small fluvial sandstone bodies that were deposited predominantly in a distributary environment. No uranium is known in the marine or eolian sandstones. Petrographically, the uranium-bearing sandstones are identical to other Cutler fluvial sandstones except that they contain less calcite and more clay and are slightly coarser grained. Ore formation has modified the host sandstones very little

Depositional environments of the uranium-bearing Cutler Formations, Lisbon Valley, Utah

Science.gov (United States)

Campbell, John A.; Steele-Mallory, Brenda A.

1979-01-01

The Cutler Formation in Lisbon Valley, San Juan County, Utah, is composed predominantly of fluvial arkosic sandstones, siltstones, shales, and mudstones that were deposited by meandering streams that flowed across a flood plain and tidal flat close to sea level. Two types of channel deposits are recognized from their sedimentary structures: meandering and distributary. The flood plain was occasionally transgressed by a shallow sea from the west, resulting in the deposition of several thin limestones and marine sandstones. The marine sandstones were deposited as longshore bars. Wind transported sand along the shoreline of the shallow sea, forming a coastal dune field. Marine sandstones and eolian sandstones are more common in the upper Cutler in the southern part of the area, whereas in the central and northern part of the area the formation is predominantly fluvial. Crossbed orientation indicates that Cutler streams flowed S. 67? W. on the the average, whereas marine currents moved sediment S. 36? E. and N. 24? W., and wind transported sand S. 800 E. The uranium in the Cutler is found in the central and northern part of the area, in the upper part of the formation, in small fluvial sandstone bodies that were deposited predominantly in a distributary environment. No uranium is known in the marine or eolian sandstones. Petrographically, the uranium-bearing sandstones are identical to other Cutler fluvial sandstones except that they contain less calcite and more clay and are slightly coarser grained. Ore formation has modified the host sandstones very little.

Lithofacies, paleoenvironment and high-resolution stratigraphy of the D5 and D6 members of the Middle Jurassic carbonates Dhruma Formation, outcrop analog, central Saudi Arabia

Science.gov (United States)

Yousif, Ibrahim M.; Abdullatif, Osman M.; Makkawi, Mohammad H.; Bashri, Mazin A.; Abdulghani, Waleed M.

2018-03-01

This study characterizes the lithofacies, paleoenvironment and stratigraphic architecture of the D5 and D6 members of carbonates Dhruma Formation outcrops in central Saudi Arabia. The study integrates detailed lithofacies analysis based on vertical and lateral profiles, in addition to thin-sections petrography to reveal the high-resolution architecture framework. Nine lithofacies types (LFTs) were defined namely: (1) skeletal peletal spiculitic wackestone (15%), (2) peloidal echinoderm packstone (19%), (3) fissile shale (36%), (4) peloidal spiculitic echinoderm pack-grainstone (5%), (5) cross-bedded peloidal skeletal oolitic grainstone (7%), (6) oolitic grainstone (2%), (7) intraformational rudstone (cycles and cycle sets with 5th to 6th orders magnitude, and thickness ranges from a few centimeters up to 6 m with an average of 1.5 m. Those are stacked to form four high-frequency sequences with thickness range from 1 m up to 14 m. The latter were grouped into a single depositional sequence of 3rd order magnitude. The architectural analysis also shows that the potential reservoir units were intensively affected by muddy-textured rocks which act as reservoir seals. These variations in the stratigraphic sequences in Middle Jurassic Dhruma Formation and its equivalents could be attributed to the eustatic sea-level changes, climate, tectonics, and local paleoenvironments. This study attempts to provide detailed insight into reservoir heterogeneity and architecture. The analog may help to understand and predict lithofacies heterogeneity, architecture, and quality in the subsurface equivalent reservoirs.

Market Concentration and Profitability of the Grocery Retailers in Central Europe

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Jindřich Špička

2016-06-01

Full Text Available The aim of the article was to internationally compare the market concentration of grocery retailers in the six countries of Central Europe – Austria, Czech Republic, Germany, Hungary, Poland and Slovakia. The market concentration was measured by CR4 ratio, Herfindahl-Hirschman Index and the GRS index. Data covered the period 2010 – 2015. The secondary data came from the Euromonitor International and Bureau van Dijk databases. The results showed that the market structure of the Central European grocery retailers has mostly a character of asymmetric oligopoly. The pairwise correlation did not reveal any strong relationship between the market power and profitability of the grocery retailers. The Central European grocery market is controlled by strong national retail chains and multinational companies which operate modern grocery retail formats. However, traditional grocery retailers are still popular in Hungary while traditional individual grocers in other countries are disappearing or gradually joining the networking system based on franchising.

Multiple Stage Ore Formation in the Chadormalu Iron Deposit, Bafq Metallogenic Province, Central Iran: Evidence from BSE Imaging and Apatite EPMA and LA-ICP-MS U-Pb Geochronology

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Hassan Heidarian

2018-02-01

Full Text Available The Chadormalu magnetite-apatite deposit in Bafq metallogenic province, Central Iran, is hosted in the late Precambrian-lower Cambrian volcano-sedimentary rocks with sodic, calcic, and potassic alterations characteristic of iron oxide copper-gold (IOCG and iron oxide-apatite (IOA ore systems. Apatite occurs as scattered irregular veinlets and disseminated grains, respectively, within and in the marginal parts of the main ore-body, as well as apatite-magnetite veins in altered wall rocks. Textural evidence (SEM-BSE images of these apatites shows primary bright, and secondary dark areas with inclusions of monazite/xenotime. The primary, monazite-free fluorapatite contains higher concentrations of Na, Si, S, and light rare earth elements (LREE. The apatite was altered by hydrothermal events that led to leaching of Na, Si, and REE + Y, and development of the dark apatite. The bright apatite yielded two U-Pb age populations, an older dominant age of 490 ± 21 Ma, similar to other iron deposits in the Bafq district and associated intrusions, and a younger age of 246 ± 17 Ma. The dark apatite yielded a U-Pb age of 437 ± 12 Ma. Our data suggest that hydrothermal magmatic fluids contributed to formation of the primary fluorapatite, and sodic and calcic alterations. The primary apatite reequilibrated with basinal brines in at least two regional extensions and basin developments in Silurian and Triassic in Central Iran.

Recent star formation in interacting galaxies

International Nuclear Information System (INIS)

Joseph, R.D.; Wright, G.S.

1985-01-01

The subset of galaxy-galaxy interactions which have resulted in a merger are, as a class, ultraluminous IR galaxies. Their IR luminosities span a narrow range which overlaps with the most luminous Seyfert galaxies. However, in contrast with Seyfert galaxies, the available optical, IR, and radio properties of mergers show no evidence for a compact non-thermal central source, and are easily understood in terms of a burst of star formation of extraordinary intensity and spatial extent; they are 'super starbursts'. We argue that super starbursts occur in the evolution of most mergers, and discuss the implications of super starbursts for the suggestion that mergers evolve into elliptical galaxies. Finally, we note that merger-induced shocks are likely to leave the gas from both galaxies in dense molecular form which will rapidly cool, collapse, and fragment. Thus a merger might in fact be expected to result in a burst of star formation of exceptional intensity and spatial extent, i.e. a super starburst. (author)

Grain processes in massive star formation

International Nuclear Information System (INIS)

Wolfire, M.G.; Cassinelli, J.P.

1986-01-01

Observational evidence suggests that stars greater than 100 M(solar) exist in the Galaxy and Large Magellanic Cloud (LMC), however classical star formation theory predicts stellar mass limits of only approx. 60 M(solar). A protostellar accretion flow consists of inflowing gas and dust. Grains are destroyed as they are near the central protostar creating a dust shell or cocoon. Radiation pressure acting on the grain can halt the inflow of material thereby limiting the amount of mass accumulated by the protostar. We first consider rather general constraints on the initial grain to gas ratio and mass accretion rates that permit inflow. We further constrain these results by constructing a numerical model. Radiative deceleration of grains and grain destruction processes are explicitly accounted for in an iterative solution of the radiation-hydrodynamic equations. Findings seem to suggest that star formation by spherical accretion requires rather extreme preconditioning of the grain and gas environment

Pattern formation and three-dimensional instability in rotating flows

Science.gov (United States)

Christensen, Erik A.; Aubry, Nadine; Sorensen, Jens N.

1997-03-01

A fluid flow enclosed in a cylindrical container where fluid motion is created by the rotation of one end wall as a centrifugal fan is studied. Direct numerical simulations and spatio-temporal analysis have been performed in the early transition scenario, which includes a steady-unsteady transition and a breakdown of axisymmetric to three-dimensional flow behavior. In the early unsteady regime of the flow, the central vortex undergoes a vertical beating motion, accompanied by axisymmetric spikes formation on the edge of the breakdown bubble. As traveling waves, the spikes move along the central vortex core toward the rotating end-wall. As the Reynolds number is increased further, the flow undergoes a three-dimensional instability. The influence of the latter on the previous patterns is studied.

Biofilm Formation As a Response to Ecological Competition.

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Nuno M Oliveira

2015-07-01

Full Text Available Bacteria form dense surface-associated communities known as biofilms that are central to their persistence and how they affect us. Biofilm formation is commonly viewed as a cooperative enterprise, where strains and species work together for a common goal. Here we explore an alternative model: biofilm formation is a response to ecological competition. We co-cultured a diverse collection of natural isolates of the opportunistic pathogen Pseudomonas aeruginosa and studied the effect on biofilm formation. We show that strain mixing reliably increases biofilm formation compared to unmixed conditions. Importantly, strain mixing leads to strong competition: one strain dominates and largely excludes the other from the biofilm. Furthermore, we show that pyocins, narrow-spectrum antibiotics made by other P. aeruginosa strains, can stimulate biofilm formation by increasing the attachment of cells. Side-by-side comparisons using microfluidic assays suggest that the increase in biofilm occurs due to a general response to cellular damage: a comparable biofilm response occurs for pyocins that disrupt membranes as for commercial antibiotics that damage DNA, inhibit protein synthesis or transcription. Our data show that bacteria increase biofilm formation in response to ecological competition that is detected by antibiotic stress. This is inconsistent with the idea that sub-lethal concentrations of antibiotics are cooperative signals that coordinate microbial communities, as is often concluded. Instead, our work is consistent with competition sensing where low-levels of antibiotics are used to detect and respond to the competing genotypes that produce them.

Effects of low central fuelling on density and ion temperature profiles in reversed shear plasmas on JT-60U

Energy Technology Data Exchange (ETDEWEB)

Takenaga, H; Ide, S; Sakamoto, Y; Fujita, T [Japan Atomic Energy Agency, Naka Ibaraki 311-0193 (Japan)], E-mail: takenaga.hidenobu@jaea.go.jp

2008-07-15

Effects of low central fuelling on density and ion temperature profiles have been investigated using negative ion based neutral beam injection and electron cyclotron heating (ECH) in reversed shear plasmas on JT-60U. Strong internal transport barrier (ITB) was maintained in density and ion temperature profiles, when central fuelling was decreased by switching positive ion based neutral beam injection to ECH after the strong ITB formation. Similar density and ion temperature ITBs were formed for the low and high central fuelling cases during the plasma current ramp-up phase. Strong correlation between the density gradient and the ion temperature gradient was observed, indicating that particle transport and ion thermal transport are strongly coupled or the density gradient assists the ion temperature ITB formation through suppression of drift wave instabilities such as ion temperature gradient mode. These results support that the density and ion temperature ITBs can be formed under reactor relevant conditions.

Effects of low central fuelling on density and ion temperature profiles in reversed shear plasmas on JT-60U

Science.gov (United States)

Takenaga, H.; Ide, S.; Sakamoto, Y.; Fujita, T.; JT-60 Team

2008-07-01

Effects of low central fuelling on density and ion temperature profiles have been investigated using negative ion based neutral beam injection and electron cyclotron heating (ECH) in reversed shear plasmas on JT-60U. Strong internal transport barrier (ITB) was maintained in density and ion temperature profiles, when central fuelling was decreased by switching positive ion based neutral beam injection to ECH after the strong ITB formation. Similar density and ion temperature ITBs were formed for the low and high central fuelling cases during the plasma current ramp-up phase. Strong correlation between the density gradient and the ion temperature gradient was observed, indicating that particle transport and ion thermal transport are strongly coupled or the density gradient assists the ion temperature ITB formation through suppression of drift wave instabilities such as ion temperature gradient mode. These results support that the density and ion temperature ITBs can be formed under reactor relevant conditions.

CRED 40 m Gridded bathymetry of Howland Island, Pacific Remote Island Areas, Central Pacific (Arc ASCII Format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (40 m cell size) bathymetry of the shelf and slope environments of Howland Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

CRED 5 m Gridded bathymetry of Jarvis Island, Pacific Remote Island Areas, Central Pacific (Arc ASCII Format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (5 m cell size) bathymetry of the shelf and slope environments of Jarvis Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

CRED 40 m Gridded bathymetry of Baker Island, Pacific Remote Island Areas, Central Pacific (Arc ASCII Format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (40 m cell size) bathymetry of the shelf and slope environments of Baker Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

Molecular gas and star formation in the centers of Virgo spirals

International Nuclear Information System (INIS)

Canzian, B.

1990-01-01

The CO and H alpha flux distributions for a sample of Virgo spirals were mapped out in an attempt to understand the coupling between gas dynamics and star formation in spiral galaxies. A broad range of morphological types were observed (types Sab through Scd) under the hypothesis that the gas dynamics is most influential in determining the overall appearance of a spiral galaxy. Only non-barred spirals were considered so that the well-studied but complicated properties of bars and their role in inducing star formation would not be a factor. All galaxies were chosen from the Virgo cluster to eliminate uncertainties due to distance errors. Since the dynamical seat of a spiral is at its center, it was expected that the dynamics of the central region would influence global properties of the rest of the disk. This could happen through the existence or absence of an inner Lindblad resonance (according to the degree of central concentration of mass) to modulate swing amplification of spiral waves, or the persistence of an oval distortion to initiate an instability which leads to spiral structure

Central sleep apnea

Science.gov (United States)

Sleep apnea - central; Obesity - central sleep apnea; Cheyne-Stokes - central sleep apnea; Heart failure - central sleep apnea ... Central sleep apnea results when the brain temporarily stops sending signals to the muscles that control breathing. The condition ...

Mechanisms of lumen formation during sprouting angiogenesis in vivo

OpenAIRE

Gebala, V. M.

2016-01-01

During development, vascular networks expand following a process known as sprouting angiogenesis. New vascular branches arise from pre-existing vessels through the coordinated migration and proliferation of endothelial cells, and eventually connect to form new vascular loops. The functionality of these new vessel segments is dependent on the opening of a central lumen to allow perfusion. While mechanisms of lumen formation during the establishment of the primary vasculature by vasculogenesis ...

Patterns of partnership formation among lone mothers in Russia

OpenAIRE

Cordula Zabel

2008-01-01

This study examines the determinants of partnership formation among lone mothers in Russia, using data from the Russian Generations and Gender Survey (GGS) and the Education and Employment Survey (EES). The central research question is whether difficult economic circumstances pressure lone mothers to enter new partnerships sooner than they would under other circumstances, limiting their freedom of choice of type of living arrangement. The empirical results show that while occupation influence...

CRED 5 m Gridded bathymetry of Baker Island, Pacific Remote Island Areas, Central Pacific (Arc ASCII Format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (5 m cell size) bathymetry of the shelf and slope environments of Baker Island, Pacific Remote Isand Areas, Central Pacific. Almost complete bottom coverage...

The Suitable Geological Formations for Spent Fuel Disposal in Romania

International Nuclear Information System (INIS)

Marunteanu, C.; Ionita, G.; Durdun, I.

2007-01-01

Using the experience in the field of advanced countries and formerly Romanian program data, ANDRAD, the agency responsible for the disposal of radioactive wastes, started the program for spent fuel disposal in deep geological formations with a documentary analysis at the national scale. The potential geological formations properly characterized elsewhere in the world: salt, clay, volcanic tuff, granite and crystalline rocks,. are all present in Romania. Using general or specific selection criteria, we presently consider the following two areas for candidate geological formations: 1. Clay formations in two areas in the western part of Romania: (1) The Pannonian basin Socodor - Zarand, where the clay formation is 3000 m thick, with many bentonitic strata and undisturbed structure, and (2) The Eocene Red Clay on the Somes River, extending 1200 m below the surface. They both need a large investigation program in order to establish and select the required homogeneous, dry and undisturbed zones at a suitable depth. 2. Old platform green schist formations, low metamorphosed, quartz and feldspar rich rocks, in the Central Dobrogea structural unit, not far from Cernavoda NPP (30 km average distance), 3000 m thick and including many homogeneous, fine granular, undisturbed, up to 300 m thick layers. (authors)

Sheet, ligament and droplet formation in swirling primary atomization

Directory of Open Access Journals (Sweden)

Changxiao Shao

2018-04-01

Full Text Available We report direct numerical simulations of swirling liquid atomization to understand the physical mechanism underlying the sheet breakup of a non-turbulent liquid swirling jet which lacks in-depth investigation. The volume-of-fluid (VOF method coupled with adapted mesh refinement (AMR technique in GERRIS code is employed in the present simulation. The mechanisms of sheet, ligament and droplet formation are investigated. It is observed that the olive-shape sheet structure is similar to the experimental result qualitatively. The numerical results show that surface tension, pressure difference and swirling effect contribute to the contraction and extension of liquid sheet. The ligament formation is partially at the sheet rim or attributed to the extension of liquid hole. Especially, the movement of hairpin vortex exerts by an anti-radial direction force to the sheet surface and leads to the sheet thinness. In addition, droplet formation is attributed to breakup of ligament and central sheet.

Sheet, ligament and droplet formation in swirling primary atomization

Science.gov (United States)

Shao, Changxiao; Luo, Kun; Chai, Min; Fan, Jianren

2018-04-01

We report direct numerical simulations of swirling liquid atomization to understand the physical mechanism underlying the sheet breakup of a non-turbulent liquid swirling jet which lacks in-depth investigation. The volume-of-fluid (VOF) method coupled with adapted mesh refinement (AMR) technique in GERRIS code is employed in the present simulation. The mechanisms of sheet, ligament and droplet formation are investigated. It is observed that the olive-shape sheet structure is similar to the experimental result qualitatively. The numerical results show that surface tension, pressure difference and swirling effect contribute to the contraction and extension of liquid sheet. The ligament formation is partially at the sheet rim or attributed to the extension of liquid hole. Especially, the movement of hairpin vortex exerts by an anti-radial direction force to the sheet surface and leads to the sheet thinness. In addition, droplet formation is attributed to breakup of ligament and central sheet.

Effects of wind on the dynamics of the central jet during drop impact onto a deep-water surface

Science.gov (United States)

Liu, Xinan; Wang, An; Wang, Shuang; Dai, Dejun

2018-05-01

The cavity and central jet generated by the impact of a single water drop on a deep-water surface in a wind field are experimentally studied. Different experiments are performed by varying the impacting drop diameter and wind speed. The contour profile histories of the cavity (also called crater) and central jet (also called stalk) are measured in detail with a backlit cinematic shadowgraph technique. The results show that shortly after the drop hits the water surface an asymmetrical cavity appears along the wind direction, with a train of capillary waves on the cavity wall. This is followed by the formation of an inclined central jet at the location of the drop impact. It is found that the wind has little effect on the penetration depth of the cavity at the early stage of the cavity expansion, but markedly changes the capillary waves during the retraction of the cavity. The capillary waves in turn shift the position of the central jet formation leeward. The dynamics of the central jet are dominated by two mechanisms: (i) the oblique drop impact produced by the wind and (ii) the wind drag force directly acting on the jet. The maximum height of the central jet, called the stalk height, is drastically affected by the wind, and the nondimensional stalk height H /D decreases with increasing θ Re-1 , where D is the drop diameter, θ is the impingement angle of drop impact, and Re=ρaUwD /μa is the Reynolds number with air density ρa, wind speed Uw, and air viscosity μa.

PKCalpha regulates platelet granule secretion and thrombus formation in mice.

Science.gov (United States)

Konopatskaya, Olga; Gilio, Karen; Harper, Matthew T; Zhao, Yan; Cosemans, Judith M E M; Karim, Zubair A; Whiteheart, Sidney W; Molkentin, Jeffery D; Verkade, Paul; Watson, Steve P; Heemskerk, Johan W M; Poole, Alastair W

2009-02-01

Platelets are central players in atherothrombosis development in coronary artery disease. The PKC family provides important intracellular mechanisms for regulating platelet activity, and platelets express several members of this family, including the classical isoforms PKCalpha and PKCbeta and novel isoforms PKCdelta and PKCtheta. Here, we used a genetic approach to definitively demonstrate the role played by PKCalpha in regulating thrombus formation and platelet function. Thrombus formation in vivo was attenuated in Prkca-/- mice, and PKCalpha was required for thrombus formation in vitro, although this PKC isoform did not regulate platelet adhesion to collagen. The ablation of in vitro thrombus formation in Prkca-/- platelets was rescued by the addition of ADP, consistent with the key mechanistic finding that dense-granule biogenesis and secretion depend upon PKCalpha expression. Furthermore, defective platelet aggregation in response to either collagen-related peptide or thrombin could be overcome by an increase in agonist concentration. Evidence of overt bleeding, including gastrointestinal and tail bleeding, was not seen in Prkca-/- mice. In summary, the effects of PKCalpha ablation on thrombus formation and granule secretion may implicate PKCalpha as a drug target for antithrombotic therapy.

Kinematic evidence for feedback-driven star formation in NGC 1893

Science.gov (United States)

Lim, Beomdu; Sung, Hwankyung; Bessell, Michael S.; Lee, Sangwoo; Lee, Jae Joon; Oh, Heeyoung; Hwang, Narae; Park, Byeong-Gon; Hur, Hyeonoh; Hong, Kyeongsoo; Park, Sunkyung

2018-06-01

OB associations are the prevailing star-forming sites in the Galaxy. Up to now, the process of how OB associations were formed remained a mystery. A possible process is self-regulating star formation driven by feedback from massive stars. However, although a number of observational studies uncovered various signposts of feedback-driven star formation, the effectiveness of such feedback has been questioned. Stellar and gas kinematics is a promising tool to capture the relative motion of newborn stars and gas away from ionizing sources. We present high-resolution spectroscopy of stars and gas in the young open cluster NGC 1893. Our findings show that newborn stars and the tadpole nebula Sim 130 are moving away from the central cluster containing two O-type stars, and that the time-scale of sequential star formation is about 1 Myr within a 9 pc distance. The newborn stars formed by feedback from massive stars account for at least 18 per cent of the total stellar population in the cluster, suggesting that this process can play an important role in the formation of OB associations. These results support the self-regulating star formation model.

Soil formation and soil biological properties post mining sites after coal mining in central Europe

Czech Academy of Sciences Publication Activity Database

Kaneda, Satoshi; Frouz, Jan; Krištůfek, Václav; Elhottová, Dana; Pižl, Václav; Starý, Josef; Háněl, Ladislav; Tajovský, Karel; Chroňáková, Alica

2007-01-01

Roč. 53, - (2007), s. 13 ISSN 0288-5840. [Annual Meeting Japanese Society of Soil Science and Plant Nutrition . 22.08.2007, Setagaya city] Institutional research plan: CEZ:AV0Z60660521 Keywords : soil formation * soil biological properties * post mining sites Subject RIV: EH - Ecology, Behaviour

C. albicans Growth, Transition, Biofilm Formation, and Gene Expression Modulation by Antimicrobial Decapeptide KSL-W

Science.gov (United States)

2013-11-07

RESEARCH ARTICLE Open Access C. albicans growth, transition, biofilm formation, and gene expression modulation by antimicrobial decapeptide KSL-W...at the end of the article © 2013 Theberge et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the...microbial growth and plaque formation by surfactant drugs. J Periodontal Res 1978, 13:474–485. 36. Semlali A, Leung KP, Curt S, Rouabhia M

RADIATION-DRIVEN IMPLOSION AND TRIGGERED STAR FORMATION

International Nuclear Information System (INIS)

Bisbas, Thomas G.; Wuensch, Richard; Whitworth, Anthony P.; Walch, Stefanie; Hubber, David A.

2011-01-01

We present simulations of initially stable isothermal clouds exposed to ionizing radiation from a discrete external source, and identify the conditions that lead to radiatively driven implosion and star formation. We use the smoothed particle hydrodynamics code SEREN and a HEALPix-based photoionization algorithm to simulate the propagation of the ionizing radiation and the resulting dynamical evolution of the cloud. We find that the incident ionizing flux, Φ LyC , is the critical parameter determining the cloud evolution. At moderate fluxes, a large fraction of the cloud mass is converted into stars. As the flux is increased, the fraction of the cloud mass that is converted into stars and the mean masses of the individual stars both decrease. Very high fluxes simply disperse the cloud. Newly formed stars tend to be concentrated along the central axis of the cloud (i.e., the axis pointing in the direction of the incident flux). For given cloud parameters, the time, t * , at which star formation starts is proportional to Φ -1/3 LyC . The pattern of star formation found in the simulations is similar to that observed in bright-rimmed clouds.

Prospects of the "WSO-UV" Project for Star Formation Study in Nearby Dwarf Galaxies

Science.gov (United States)

Makarova, L. N.; Makarov, D. I.

2017-12-01

In the present work we consider the questions of star formation and evolution of nearby dwarf galaxies. We describe the method of star formation history determination based on multicolor photometry of resolved stars and models of color-magnitude diagrams of the galaxies. We present the results of star formation rate determination and its dependence on age and metallicity for dwarf irregular and dwarf spheroidal galaxies in the two nearby galaxy groups M81 and Cen A. Similar age of the last episode of star formation in the central part of the M81 group and also unusually high level of metal enrichment in the several galaxies of the Cen A group are mentioned. We pay special attention to the consideration of perspectives of star formation study in nearby dwarf galaxies with he new WSO-UV observatory.

Basaltic ring structures of the Serra Geral Formation at the southern Triângulo Mineiro, Água Vermelha region, Brazil

Science.gov (United States)

Pacheco, Fernando Estevão Rodrigues Crincoli; Caxito, Fabricio de Andrade; Moraes, Lucia Castanheira de; Marangoni, Yara Regina; Santos, Roberto Paulo Zanon dos; Pedrosa-Soares, Antonio Carlos

2018-04-01

The Serra Geral Formation constitutes a continental magmatic province on the southern part of South America within the Paraná basin. Basaltic magmatism of the Serra Geral Formation occurred as extrusions at around 134.5 to 131.5 My ago. The formation is part of the Paraná-Etendeka large igneous province, spanning South America and southwestern Africa. The main extrusion mechanism was probably through fissures related to extensional regime during the breakup of Gondwana in the Cretaceous. Basaltic ring structures (BRS) with tens of meters of diameter, cropping out downstream of Grande river at Água Vermelha hydroelectric dam in southern Triângulo Mineiro region, enable the study of the mechanism of extrusion. The origin of the BRS has been subject to differing interpretations in the past, either collapsed lava flows or central conduits. Detailed geological mapping at 1:1000 scale, stratigraphic, petrographic and gravimetric analysis of the most well preserved of the BRS, with a 200 m diameter, has enabled the description of thirteen different basalt lava flows, along with single a central lava lake and a ring dyke structure. The central flow, interpreted as a preserved lava lake, comprises vesicle- and amygdale-rich basalt, spatter, ropy and degassing structures. The most basal of the thirteen lava flows has massive basalt containing geodes filled with quartz. Above, the lava flows show massive basalt with vertical columnar jointing where is possible to identify the top and bottom of each individual flow, with gentle dips towards the perimeter of the structure. A prominent ring dyke dipping towards the lava lake presents horizontal columnar jointing and cuts the basal and central flows. The gravimetric analysis shows a weak negative Bouguer anomaly on the center of the BRS. The proposed model describes the volcanism of the region in three main steps: (1) fissure flow occurs with lava input; (2) this lava cools and crystallizes cementing most of the fissures

Fundamental Flaws in the Architecture of the European Central Bank: The Possible End of the Euro Zone and its Effects to East African Community (EAC Countries

Directory of Open Access Journals (Sweden)

Nothando Moyo

2014-09-01

Full Text Available European countries embarked on a European integration programme that saw the formation of the Euro, which has emerged as a major currency (Blair, 1999 that was introduced in 1998. With the Euro, came the establishment of the European Central Bank. Thus this study seeks to investigate the flaws in the formation of the European Central Bank that surfaced during the major economic crisis in Europe. The crisis revealing the gaps in the formation and structure of the European central bank have created major challenges for the Economic and Monetary Union (EMU. Through an extant review of literature the study will examine the East African Community Countries, investigating the ties they have to the euro zone to analyse how the crisis has affected them. Furthermore, the study will analyse what would happen to the growth patterns of the East African Countries and the various prospects they may have should the Eurozone come to an end.

Formation of protostars in collapsing, rotating, turbulent clouds

International Nuclear Information System (INIS)

Regev, O.; Shaviv, G.

1981-01-01

Collapse and star formation processes in rotating turbulent interstellar gas clouds have been studied. For this purpose numerical collapse calculations have been performed for a number of representative cases. These calculations have been carried out by a two-dimensional hydrodynamical computer code, which solves the equations of hydrodynamics explicitly, coupled to the Poisson equation. The computer code has been written especially for this work and has been thoroughly tested. The calculations in this work have been performed with an effort to obtain physically reliable results (by repeating the same calculations with different numerical spatial resolutions). A physical mechanism for angular momentum transport by turbulent viscosity has been proposed and incorporated in new collapse calculations. The main results can be summerized as follows: When there is no physical mechanism for angular momentum transport, the result of the collaps is a ringlike structure. The turbulent viscosity affects the nature of the collaps. For the two cases studied, the mass of the central object is a major fraction (30%) of the total mass of the system. The exact form of the central object and its ultimate fate depend on the parameters, especially rotational energy/gravitational energy and Re. The present calculations cannot predict the future evolution of the central object. In the new theoretical model proposed, a central protostar forms as a result of the collaps of a protostellar rotating cloud

Spermine oxidase promotes bile canalicular lumen formation through acrolein production.

Science.gov (United States)

Uemura, Takeshi; Takasaka, Tomokazu; Igarashi, Kazuei; Ikegaya, Hiroshi

2017-11-01

Spermine oxidase (SMOX) catalyzes oxidation of spermine to generate spermidine, hydrogen peroxide (H 2 O 2 ) and 3-aminopropanal, which is spontaneously converted to acrolein. SMOX is induced by a variety of stimuli including bacterial infection, polyamine analogues and acetaldehyde exposure. However, the physiological functions of SMOX are not yet fully understood. We investigated the physiological role of SMOX in liver cells using human hepatocellular carcinoma cell line HepG2. SMOX localized to the bile canalicular lumen, as determined by F-actin staining. Knockdown of SMOX reduced the formation of bile canalicular lumen. We also found that phospho-Akt (phosphorylated protein kinase B) was localized to canalicular lumen. Treatment with Akt inhibitor significantly reduced the formation of bile canalicular lumen. Acrolein scavenger also inhibited the formation of bile canalicular lumen. PTEN, phosphatase and tensin homolog and an inhibitor of Akt, was alkylated in a SMOX-dependent manner. Our results suggest that SMOX plays a central role in the formation of bile canalicular lumen in liver cells by activating Akt pathway through acrolein production.

Implementation of warm-cloud processes in a source-oriented WRF/Chem model to study the effect of aerosol mixing state on fog formation in the Central Valley of California

Directory of Open Access Journals (Sweden)

H.-H. Lee

2016-07-01

Full Text Available The source-oriented Weather Research and Forecasting chemistry model (SOWC was modified to include warm cloud processes and was applied to investigate how aerosol mixing states influence fog formation and optical properties in the atmosphere. SOWC tracks a 6-D chemical variable (X, Z, Y, size bins, source types, species through an explicit simulation of atmospheric chemistry and physics. A source-oriented cloud condensation nuclei module was implemented into the SOWC model to simulate warm clouds using the modified two-moment Purdue Lin microphysics scheme. The Goddard shortwave and long-wave radiation schemes were modified to interact with source-oriented aerosols and cloud droplets so that aerosol direct and indirect effects could be studied. The enhanced SOWC model was applied to study a fog event that occurred on 17 January 2011, in the Central Valley of California. Tule fog occurred because an atmospheric river effectively advected high moisture into the Central Valley and nighttime drainage flow brought cold air from mountains into the valley. The SOWC model produced reasonable liquid water path, spatial distribution and duration of fog events. The inclusion of aerosol–radiation interaction only slightly modified simulation results since cloud optical thickness dominated the radiation budget in fog events. The source-oriented mixture representation of particles reduced cloud droplet number relative to the internal mixture approach that artificially coats hydrophobic particles with hygroscopic components. The fraction of aerosols activating into cloud condensation nuclei (CCN at a supersaturation of 0.5 % in the Central Valley decreased from 94 % in the internal mixture model to 80 % in the source-oriented model. This increased surface energy flux by 3–5 W m−2 and surface temperature by as much as 0.25 K in the daytime.

Tectonic Evolution of the Çayirhan Neogene Basin (Ankara), Central Turkey

Science.gov (United States)

Behzad, Bezhan; Koral, Hayrettin; İşb&idot; l, Duygu; Karaaǧa; ç, Serdal

2016-04-01

Çayırhan (Ankara) is located at crossroads of the Western Anatolian extensional region, analogous to the Basin and Range Province, and suture zone of the Neotethys-Ocean, which is locus of the North Anatolian Transform since the Late Miocene. To the north of Çayırhan (Ankara), a Neogene sedimentary basin comprises Lower-Middle Miocene and Upper Miocene age formations, characterized by swamp, fluvial and lacustrine settings respectively. This sequence is folded and transected by neotectonic faults. The Sekli thrust fault is older than the Lower-Middle Miocene age formations. The Davutoǧlan fault is younger than the Lower-Middle Miocene formations and is contemporaneous to the Upper Miocene formation. The Çatalkaya fault is younger than the Upper Miocene formation. The sedimentary and tectonic features provide information on mode, timing and evolution of this Neogene age sedimentary basin in Central Turkey. It is concluded that the region underwent a period of uplift and erosion under the influence of contractional tectonics prior to the Early-Middle Miocene, before becoming a semi-closed basin under influence of transtensional tectonics during the Early-Middle Miocene and under influence of predominantly extensional tectonics during the post-Late Miocene times. Keywords: Tectonics, Extension, Transtension, Stratigraphy, Neotectonic features.

Morphogenesis and pattern formation in biological systems experiments and models

CERN Document Server

Noji, Sumihare; Ueno, Naoto; Maini, Philip

2003-01-01

A central goal of current biology is to decode the mechanisms that underlie the processes of morphogenesis and pattern formation. Concerned with the analysis of those phenomena, this book covers a broad range of research fields, including developmental biology, molecular biology, plant morphogenesis, ecology, epidemiology, medicine, paleontology, evolutionary biology, mathematical biology, and computational biology. In Morphogenesis and Pattern Formation in Biological Systems: Experiments and Models, experimental and theoretical aspects of biology are integrated for the construction and investigation of models of complex processes. This collection of articles on the latest advances by leading researchers not only brings together work from a wide spectrum of disciplines, but also provides a stepping-stone to the creation of new areas of discovery.

Orden monetario y bancos centrales Monetary order and Central Banks

Directory of Open Access Journals (Sweden)

Aglietta Michel

1996-06-01

Full Text Available Con el enfoque evolucionista e institucionalista de la economía de las convenciones francesa, este trabajo analiza el surgimiento histórico de la banca central y la creación institucional del 'arte de la banca central'. El artículo estudia los modelos formales del orden monetario, la banca libre y la banca central, y analiza los eventos históricos que llevaron a que el Banco de Inglaterra inventara el arte de manejar los bancos centrales en conjunción con el aprendizaje colectivo e institucional que lo hizo posible. Aglietta muestra que la banca central no es una creación del Estado sino una creación institucional endógena al sistema de mercado.With the evolutionist and institutionalist focus of the economics of the French conventions, this paper analyzes the historical rise of the central bank and the institutional creation of the 'art of the central bank'. The article studies formal models of the monetary order, free banking and the central bank, and analyzes the historie events that led to the Bank of England inventing the art of managing the central banks, in conjunction with the collective and institutional learning that made it possible. Aglietta shows that the central bank is not a creation of the State, but rather aninstitutional creation endogenous to the market system.

The Regional Centrality of Vietnam’s Central Highlands

DEFF Research Database (Denmark)

Salemink, Oscar

2018-01-01

strategic value turned it into a battleground among various Vietnamese parties, France, and the United States. It was here that the outcome of the Indochina wars was determined, but at a terrible price for the local population. After the adoption of economic reforms in reunified Vietnam the Central......Vietnam’s Central Highlands—or Tây Nguyên—area is usually described as remote, backward, and primitive, but this region has played a central role in the history of the surrounding states and the wider East and Southeast Asia region. Far from isolated, the Central Highlands engaged in trade...... various rivalrous polities now known as Vietnam, Champa, Cambodia, Laos, and Thailand, the area occupied a strategic position in the wider mainland Southeast Asia region. With the emergence of a unified, neo-Confucianist Vietnamese state the region lost its centrality until the late colonial era, when its...

NON-IDEAL MHD EFFECTS AND MAGNETIC BRAKING CATASTROPHE IN PROTOSTELLAR DISK FORMATION

International Nuclear Information System (INIS)

Li Zhiyun; Krasnopolsky, Ruben; Shang Hsien

2011-01-01

Dense, star-forming cores of molecular clouds are observed to be significantly magnetized. A realistic magnetic field of moderate strength has been shown to suppress, through catastrophic magnetic braking, the formation of a rotationally supported disk (RSD) during the protostellar accretion phase of low-mass star formation in the ideal MHD limit. We address, through two-dimensional (axisymmetric) simulations, the question of whether realistic levels of non-ideal effects, computed with a simplified chemical network including dust grains, can weaken the magnetic braking enough to enable an RSD to form. We find that ambipolar diffusion (AD), the dominant non-ideal MHD effect over most of the density range relevant to disk formation, does not enable disk formation, at least in two dimensions. The reason is that AD allows the magnetic flux that would be dragged into the central stellar object in the ideal MHD limit to pile up instead in a small circumstellar region, where the magnetic field strength (and thus the braking efficiency) is greatly enhanced. We also find that, on the scale of tens of AU or more, a realistic level of Ohmic dissipation does not weaken the magnetic braking enough for an RSD to form, either by itself or in combination with AD. The Hall effect, the least explored of these three non-ideal MHD effects, can spin up the material close to the central object to a significant, supersonic rotation speed, even when the core is initially non-rotating, although the spun-up material remains too sub-Keplerian to form an RSD. The problem of catastrophic magnetic braking that prevents disk formation in dense cores magnetized to realistic levels remains unresolved. Possible resolutions of this problem are discussed.

A new pterosaur tracksite from the Jurassic Summerville formation, near Ferron, Utah

Science.gov (United States)

Mickelson, Debra L.; Lockley, Martin G.; Bishop, John; Kirkland, James I.

2003-01-01

Pterosaur tracks (cf. Pteraichnus) from the Summerville Formation of the Ferron area of central Utah add to the growing record of Pteraichnus tracksites in the Late Jurassic Summerville Formation and time-equivalent, or near time-equivalent, deposits. The site is typical in revealing high pterosaur track densities, but low ichnodiversity suggesting congregations or “flocks” of many individuals. Footprint length varies from 2.0 to 7.0 cms. The ratio of well-preserved pes:manus tracks is about 1:3.4. This reflects a bias in favor of preservation of manus tracks due to the greater weight-bearing role of the front limbs, as noted in other pterosaur track assemblages. The sample also reveals a number of well-preserved trackways including one suggestive of pes-only progression that might be associated with take off or landing, and another that shows pronounced lengthening of stride indicating acceleration.One well-preserved medium-sized theropod trackway (Therangospodus) and other larger theropod track casts (cf. Megalosauripus) are associated with what otherwise appears to be a nearly monospecific pterosaur track assemblage. However, traces of a fifth pes digit suggest some tracks are of rhamphorynchoid rather than pterodactyloid origin, as usually inferred for Pteraichnus. The tracks occur at several horizons in a thin stratigraphic interval of ripple marked sandstones and siltstones. Overall the assemblage is similar to others found in the same time interval in the Western Interior from central and eastern Utah through central and southern Wyoming, Colorado, northeastern Arizona, and western Oklahoma. This vast “Pteraichnusichnofacies,” with associated saurischian tracks, remains the only ichnological evidence of pre-Cretaceous pterosaurs in North America and sheds important light on the vertebrate ecology of the Summerville Formation and contiguous deposits.

Wind Climate Analyses for SRTC's Central Climatology Site

International Nuclear Information System (INIS)

Weber, A.H.

2003-01-01

This report was written to present climatological summaries of the wind data at the Central Climatology (CC) tower in a convenient format and to point out some features of the wind speed and direction that have not been widely appreciated in the past. Short-term (two-week) wind roses provide a means to demonstrate the temporal and spatial relationships that wind speed and direction undergo using a ten-year database from the CC tower. These relationships are best demonstrated by examining the figures provided in this report or looking at loops of computer-generated images provided by the authors

The Central European, Tarim and Siberian Large Igneous Provinces, Late Palaeozoic orogeny and coeval metallogeny

NARCIS (Netherlands)

de Boorder, H.|info:eu-repo/dai/nl/098199056

2014-01-01

The formation of the Central European and Tarim Large Igneous Provinces (LIPs) in the Early Permian coincided with the demise of the Variscan and the Southern Tianshan orogens, respectively. The Early Triassic Siberian LIP was formed in the wake of the Western Altaid orogeny in the Late Permian.

Central regions of LIRGs: rings, hidden starbursts, Supernovae and star clusters

International Nuclear Information System (INIS)

Väisänen, Petri; Randriamanakoto, Zara; Escala, Andres; Kankare, Erkki; Mattila, Seppo; Reunanen, Juha; Kotilainen, Jari; Rajpaul, Vinesh; Ryder, Stuart; Zijlstra, Albert

2012-01-01

We study star formation (SF) in very active environments, in luminous IR galaxies, which are often interacting. A variety of phenomena are detected, such as central starbursts, circumnuclear SF, obscured SNe tracing the history of recent SF, massive super star clusters, and sites of strong off-nuclear SF. All of these can be ultimately used to define the sequence of triggering and propagation of star-formation and interplay with nuclear activity in the lives of gas rich galaxy interactions and mergers. In this paper we present analysis of high-spatial resolution integral field spectroscopy of central regions of two interacting LIRGs. We detect a nuclear 3.3 μm PAH ring around the core of NGC 1614 with thermal-IR IFU observations. The ring's characteristics and relation to the strong star-forming ring detected in recombination lines are presented, as well as a scenario of an outward expanding starburst likely initiated with a (minor) companion detected within a tidal feature. We then present NIR IFU observations of IRAS 19115-2124, aka the Bird, which is an intriguing triple encounter. The third component is a minor one, but, nevertheless, is the source of 3/4 of the SFR of the whole system. Gas inflows and outflows are detected in their nuclei locations. Finally, we briefly report on our on-going NIR adaptive optics imaging survey of several dozen LIRGs. We have detected highly obscured core-collapse SNe in the central kpc, and discuss the statistics of 'missing SNe' due to dust extinction. We are also determining the characteristics of hundreds of super star clusters in and around the core regions of LIRGs, as a function of host-galaxy properties.

STAR FORMATION IN 30 DORADUS

International Nuclear Information System (INIS)

De Marchi, Guido; Spezzi, Loredana; Sirianni, Marco; Andersen, Morten; Paresce, Francesco; Panagia, Nino; Mutchler, Max; Whitmore, Bradley C.; Bond, Howard; Beccari, Giacomo; Balick, Bruce; Dopita, Michael A.; Frogel, Jay A.; Calzetti, Daniela; Marcella Carollo, C.; Disney, Michael J.; Hall, Donald N. B.; Holtzman, Jon A.; Kimble, Randy A.; McCarthy, Patrick J.

2011-01-01

Using observations obtained with the Wide-Field Camera 3 on board the Hubble Space Telescope, we have studied the properties of the stellar populations in the central regions of 30 Dor in the Large Magellanic Cloud. The observations clearly reveal the presence of considerable differential extinction across the field. We characterize and quantify this effect using young massive main-sequence stars to derive a statistical reddening correction for most objects in the field. We then search for pre-main-sequence (PMS) stars by looking for objects with a strong (>4σ) Hα excess emission and find about 1150 of them over the entire field. Comparison of their location in the Hertzsprung-Russell diagram with theoretical PMS evolutionary tracks for the appropriate metallicity reveals that about one-third of these objects are younger than ∼4 Myr, compatible with the age of the massive stars in the central ionizing cluster R 136, whereas the rest have ages up to ∼30 Myr, with a median age of ∼12 Myr. This indicates that star formation has proceeded over an extended period of time, although we cannot discriminate between an extended episode and a series of short and frequent bursts that are not resolved in time. While the younger PMS population preferentially occupies the central regions of the cluster, older PMS objects are more uniformly distributed across the field and are remarkably few at the very center of the cluster. We attribute this latter effect to photo-evaporation of the older circumstellar disks caused by the massive ionizing members of R 136.

Blood drop patterns: Formation and applications.

Science.gov (United States)

Chen, Ruoyang; Zhang, Liyuan; Zang, Duyang; Shen, Wei

2016-05-01

The drying of a drop of blood or plasma on a solid substrate leads to the formation of interesting and complex patterns. Inter- and intra-cellular and macromolecular interactions in the drying plasma or blood drop are responsible for the final morphologies of the dried patterns. Changes in these cellular and macromolecular components in blood caused by diseases have been suspected to cause changes in the dried drop patterns of plasma and whole blood, which could be used as simple diagnostic tools to identify the health of humans and livestock. However, complex physicochemical driving forces involved in the pattern formation are not fully understood. This review focuses on the scientific development in microscopic observations and pattern interpretation of dried plasma and whole blood samples, as well as the diagnostic applications of pattern analysis. Dried drop patterns of plasma consist of intricate visible cracks in the outer region and fine structures in the central region, which are mainly influenced by the presence and concentration of inorganic salts and proteins during drying. The shrinkage of macromolecular gel and its adhesion to the substrate surface have been thought to be responsible for the formation of the cracks. Dried drop patterns of whole blood have three characteristic zones; their formation as functions of drying time has been reported in the literature. Some research works have applied engineering treatment to the evaporation process of whole blood samples. The sensitivities of the resultant patterns to the relative humidity of the environment, the wettability of the substrates, and the size of the drop have been reported. These research works shed light on the mechanisms of spreading, evaporation, gelation, and crack formation of the blood drops on solid substrates, as well as on the potential applications of dried drop patterns of plasma and whole blood in diagnosis. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Palaeocology of coal-bearing Eocene sediments in central Anatolia (Turkey) based on quantitative palynological data

Energy Technology Data Exchange (ETDEWEB)

Akkiraz, M.S.; Kayseri, M.S.; Akgun, F. [Dokuz Eylul University, Izmir (Turkey). Dept. of Geological Engineering

2008-04-15

In this study, the lignite-bearing Yoncali formation between Yozgat and Sorgun, in central Anatolia has been palynologically examined. Based on 37 outcrop samples, quantitative palynological studies recognized 64 genera and 136 palynoflora species in the palynological assemblage, which indicated a Middle-Late Eocene age. This paper also presents a quantitative palaeovegetation and palaeoclimate reconstruction for the Middle-Upper Eocene coal occurrences of Central Anatolia on the basis of palynomorph assemblages. The diversified floral and ecological characteristics of the pollen taxa indicates that the Middle-Upper Eocene formations in central Anatolia were characterized by the presence of a complex mangrove swamp with contributions by Nypa, Pelliciera, Avicennia, Diporites tszkaszentgydrgyi and dinoflagellate cysts which reflect warm climatic conditions. Lowland-riparian and montane elements are characterized by the dominance of Myricaceae, Symplocaceae, Icacinaceae, Quercus, Pinus and Castanea. Swamp-freshwater elements are represented by Sparganjaceae, Nymphaceae, Taxodjaceae, Cupressaceae and Nyssa as well as fern spores such as Osmundaceae and Gleicheniaceae. The calculations were performed with the help of the 'Coexistence Approach' method to climatically evaluate palynoflora from the Yozgat-Sorgun area. The obtained results have been compared to data derived from the application of the Coexistence Approach to other, already published Central Anatolian palynofloras of the same age. The results of the climatic inferences suggest that the palaeoclimatic conditions were in the megathermal zone, megatherm/mesotherm intermediate zone whereas mesothermic conditions prevailed in the montane region. Likewise, the results of mean annual range of temperatures indicate the influence of the Indian ocean, which enabled the development of the mangroves.

Esthetic periodontal surgery for impacted dilacerated maxillary central incisors.

Science.gov (United States)

Wei, Yu-Ju; Lin, Yi-Chun; Kaung, Shou-Shin; Yang, Shue-Fen; Lee, Shyh-Yuan; Lai, Yu-Lin

2012-10-01

Clinicians do not frequently see impacted dilacerated maxillary incisors in their patients. When they do, there are several diagnostic and management challenges for correcting root dilacerations. An unfavorable esthetic outcome might occur as a result of soft-tissue complications during surgical eruption procedures. We present 2 patients with an impacted and dilacerated maxillary central incisor. Computed tomography scans with 3-dimensional reformation were used to accurately assess the positions of the dilacerated teeth, the degree of dilaceration, and the stage of root formation. The therapy primarily involved 2-stage crown exposure surgery combined with orthodontic traction. An apicoectomy was performed on 1 dilacerated tooth; the other exhibited pulp vitality. This article highlights the periodontal surgical strategies for the esthetic management of inverted crowns. Through periodontal plastic surgery and interdisciplinary cooperation, the impacted dilacerated central incisors were properly aligned, and successful esthetic results were achieved. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

BolA Is Required for the Accurate Regulation of c-di-GMP, a Central Player in Biofilm Formation

OpenAIRE

Moreira, Ricardo N.; Dressaire, Clémentine; Barahona, Susana; Galego, Lisete; Kaever, Volkhard; Jenal, Urs; Arraiano, Cecília M.

2017-01-01

The bacterial second messenger cyclic dimeric GMP (c-di-GMP) is a nearly ubiquitous intracellular signaling molecule involved in the transition from the motile to the sessile/biofilm state in bacteria. C-di-GMP regulates various cellular processes, including biofilm formation, motility, and virulence. BolA is a transcription factor that promotes survival in different stresses and is also involved in biofilm formation. Both BolA and c-di-GMP participate in the regulation of motility mechanisms...

Centralized vs. De-centralized Multinationals and Taxes

DEFF Research Database (Denmark)

Nielsen, Søren Bo; Raimondos-Møller, Pascalis; Schjelderup, Guttorm

2005-01-01

The paper examines how country tax differences affect a multinational enterprise's choice to centralize or de-centralize its decision structure. Within a simple model that emphasizes the multiple conflicting roles of transfer prices in MNEs - here, as a strategic pre-commitment device and a tax...

Road network selection for small-scale maps using an improved centrality-based algorithm

Directory of Open Access Journals (Sweden)

Roy Weiss

2014-12-01

Full Text Available The road network is one of the key feature classes in topographic maps and databases. In the task of deriving road networks for products at smaller scales, road network selection forms a prerequisite for all other generalization operators, and is thus a fundamental operation in the overall process of topographic map and database production. The objective of this work was to develop an algorithm for automated road network selection from a large-scale (1:10,000 to a small-scale database (1:200,000. The project was pursued in collaboration with swisstopo, the national mapping agency of Switzerland, with generic mapping requirements in mind. Preliminary experiments suggested that a selection algorithm based on betweenness centrality performed best for this purpose, yet also exposed problems. The main contribution of this paper thus consists of four extensions that address deficiencies of the basic centrality-based algorithm and lead to a significant improvement of the results. The first two extensions improve the formation of strokes concatenating the road segments, which is crucial since strokes provide the foundation upon which the network centrality measure is computed. Thus, the first extension ensures that roundabouts are detected and collapsed, thus avoiding interruptions of strokes by roundabouts, while the second introduces additional semantics in the process of stroke formation, allowing longer and more plausible strokes to built. The third extension detects areas of high road density (i.e., urban areas using density-based clustering and then locally increases the threshold of the centrality measure used to select road segments, such that more thinning takes place in those areas. Finally, since the basic algorithm tends to create dead-ends—which however are not tolerated in small-scale maps—the fourth extension reconnects these dead-ends to the main network, searching for the best path in the main heading of the dead-end.

Depositional Architecture of Late Cambrian-Early Ordovician Siliciclastic Barik Formation; Al Huqf Area, Oman

Science.gov (United States)

Abbasi, Iftikhar Ahmed

2017-04-01

Early Paleozoic siliciclastics sediments of the Haima Supergroup are subdivided into a number of formations and members based on lithological characteristics of various rock sequences. One of the distinct sandstone sequence, the Barik Formation (Late Cambrian-Early Ordovician) of the Andam Group is a major deep gas reservoir in central Oman. The sandstone bodies are prospective reservoir rocks while thick shale and clay interbeds act as effective seal. Part of the Barik Formation (lower and middle part) is exposed in isolated outcrops in Al Huqf area as interbedded multistoried sandstone, and green and red shale. The sandstone bodies are up to 2 meters thick and can be traced laterally for 300 m to over 1 km. Most of sandstone bodies show both lateral and vertical stacking. Two types of sandstone lithofacies are identified on the basis of field characteristics; a plane-bedded sandstone lithofacies capping thick red and green color shale beds, and a cross-bedded sandstone lithofacies overlying the plane-bedded sandstone defining coarsening upward sequences. The plane-bedded sandstone at places contains Cruziana ichnofacies and bivalve fragments indicating deposition by shoreface processes. Thick cross-bedded sandstone is interpreted to be deposited by the fluvial dominated deltaic processes. Load-casts, climbing ripples and flaser-bedding in siltstone and red shale indicate influence of tidal processes at times during the deposition of the formation. This paper summarizes results of a study carried out in Al Huqf area outcrops to analyze the characteristics of the sandstone-body geometry, internal architecture, provenance and diagenetic changes in the lower and middle part of the formation. The study shows build-up of a delta complex and its progradation over a broad, low-angle shelf where fluvial processes operate beside shoreface processes in a vegetation free setting. Keywords: Andam Group, Barik Formation, Ordovician sandstone, Al Huqf, Central Oman,

Migration of a Central Venous Catheter in a Hemodialysis Patient Resulted in Left Atrial Perforation and Thrombus Formation Requiring Open Heart Surgery.

Science.gov (United States)

Wong, Kevin; Marks, Barry A; Qureshi, Anwer; Stemm, Joseph J

2016-07-01

Central venous catheterization is widely used in patients on hemodialysis. A rare complication associated with the clinical use of central venous catheters is perforation of the heart or major vessels. We report a case of inadvertent perforation of the left atrium and thrombosis after the placement of a hemodialysis catheter in the right internal jugular vein. In such cases, surgical removal of the central venous catheter from perforation sites in the heart and vessel walls poses anesthetic challenges because of the high risk of pneumothorax, hemorrhage, arrhythmias, thrombosis, and death.

Investigating the Dynamics of Formative Assessment: Relationships between Teacher Knowledge, Assessment Practice and Learning

Science.gov (United States)

Herman, Joan; Osmundson, Ellen; Dai, Yunyun; Ringstaff, Cathy; Timms, Michael

2015-01-01

This exploratory study of elementary school science examines questions central to policy, practice and research on formative assessment: What is the quality of teachers' content-pedagogical and assessment knowledge? What is the relationship between teacher knowledge and assessment practice? What is the relationship between teacher knowledge,…

Examining the Center: Positions, Dominance, and Star Formation Rates of Most Massive Group Galaxies at Intermediate Redshift

Science.gov (United States)

Connelly, Jennifer L.; Parker, Laura C.; McGee, Sean; Mulchaey, John S.; Finoguenov, Alexis; Balogh, Michael; Wilman, David; Group Environment Evolution Collaboration

2015-01-01

The group environment is believed to be the stage for many galaxy transformations, helping evolve blue star-forming galaxies to red passive ones. In local studies of galaxy clusters, the central member is usually a single dominant giant galaxy at the center of the potential with little star formation thought to be the result of galaxy mergers. In nearby groups, a range of morphologies and star formation rates are observed and the formation history is less clear. Further, the position and dominance of the central galaxy cannot be assumed in groups, which are less massive and evolved than clusters. To understand the connections between global group properties and properties of the central group galaxy at intermediate redshift, we examine galaxy groups from the Group Environment and Evolution Collaboration (GEEC) catalog, including both optically- and X-ray-selected groups at redshift z~0.4. The sample is diverse, containing a range in overall mass and evolutionary state. The number of groups is significant, membership is notably complete, and measurements span the IR to the UV allowing the properties of the members to be connected to those of the host groups. Having investigated trends in the global group properties previously, including mass and velocity substructure, we turn our attention now to the galaxy populations, focusing on the central regions of these systems. The most massive and second most massive group galaxies are identified by their stellar mass. The positions of the most massive galaxies (MMGs) are determined with respect to both the luminosity-weighted and X-ray center. Star formation rates are used to explore the fraction of passive/quiescent versus star-forming MMGs and the dominance of the MMGs in our group sample is also tested. Determinations of these characteristics and trends constitute the important first steps toward a detailed understanding of the relationships between the properties of host groups and their most massive galaxies and the

Structural insights into central hypertension regulation by human aminopeptidase A.

Science.gov (United States)

Yang, Yang; Liu, Chang; Lin, Yi-Lun; Li, Fang

2013-08-30

Hypertension is regulated through both the central and systemic renin-angiotensin systems. In the central renin-angiotensin system, zinc-dependent aminopeptidase A (APA) up-regulates blood pressure by specifically cleaving the N-terminal aspartate, but not the adjacent arginine, from angiotensin II, a process facilitated by calcium. Here, we determined the crystal structures of human APA and its complexes with different ligands and identified a calcium-binding site in the S1 pocket of APA. Without calcium, the S1 pocket can bind both acidic and basic residues through formation of salt bridges with the charged side chains. In the presence of calcium, the binding of acidic residues is enhanced as they ligate the cation, whereas the binding of basic residues is no longer favorable due to charge repulsion. Of the peptidomimetic inhibitors of APA, amastatin has higher potency than bestatin by fitting better in the S1 pocket and interacting additionally with the S3' subsite. These results explain the calcium-modulated substrate specificity of APA in central hypertension regulation and can guide the design and development of brain-targeting antihypertensive APA inhibitors.

Structural Insights into Central Hypertension Regulation by Human Aminopeptidase A*

Science.gov (United States)

Yang, Yang; Liu, Chang; Lin, Yi-Lun; Li, Fang

2013-01-01

Hypertension is regulated through both the central and systemic renin-angiotensin systems. In the central renin-angiotensin system, zinc-dependent aminopeptidase A (APA) up-regulates blood pressure by specifically cleaving the N-terminal aspartate, but not the adjacent arginine, from angiotensin II, a process facilitated by calcium. Here, we determined the crystal structures of human APA and its complexes with different ligands and identified a calcium-binding site in the S1 pocket of APA. Without calcium, the S1 pocket can bind both acidic and basic residues through formation of salt bridges with the charged side chains. In the presence of calcium, the binding of acidic residues is enhanced as they ligate the cation, whereas the binding of basic residues is no longer favorable due to charge repulsion. Of the peptidomimetic inhibitors of APA, amastatin has higher potency than bestatin by fitting better in the S1 pocket and interacting additionally with the S3′ subsite. These results explain the calcium-modulated substrate specificity of APA in central hypertension regulation and can guide the design and development of brain-targeting antihypertensive APA inhibitors. PMID:23888046

The Central European Permian Basins; Rheological and structural controls on basin history and on inter-basin connectivity

NARCIS (Netherlands)

Smit, Jeroen; van Wees, Jan-Diederik; Cloetingh, Sierd

2014-01-01

We analyse the relative importance of the major crustal-scale fault zones and crustal architecture in controlling basin formation, deformation and the structural connections between basins. The North and South Permian Basins of Central Europe are usually defined by the extend of Rotliegend

Mathematical Analysis of a PDE System for Biological Network Formation

KAUST Repository

Haskovec, Jan

2015-02-04

Motivated by recent physics papers describing rules for natural network formation, we study an elliptic-parabolic system of partial differential equations proposed by Hu and Cai [13, 15]. The model describes the pressure field thanks to Darcy\\'s type equation and the dynamics of the conductance network under pressure force effects with a diffusion rate D >= 0 representing randomness in the material structure. We prove the existence of global weak solutions and of local mild solutions and study their long term behavior. It turns out that, by energy dissipation, steady states play a central role to understand the network formation capacity of the system. We show that for a large diffusion coefficient D, the zero steady state is stable, while network formation occurs for small values of D due to the instability of the zero steady state, and the borderline case D = 0 exhibits a large class of dynamically stable (in the linearized sense) steady states.

Zeolites of the Valle Central of Costa Rica and its outskirts; Zeolitas del Valle Central de Costa Rica y sus alrededores

Energy Technology Data Exchange (ETDEWEB)

Zeledon, Luis Alonso [Moravia, San Jose, (Costa Rica)

2004-12-15

19 different species of zeolites have been found in 25 outcrops in the Valle Central of Costa Rica and in the Siquirres region. All the zeolites are secondary minerals and crystallized in little veins and vesicles of the basalts and pyroclastics rocks of the La Cruz and Grifo Alto formations, belonging to the Aguacate Group and the alkaline igneous rocks of Guayacan. The most frequent species of zeolites are stibnite, chabasite, laumontite, mesolite/mordenite, thomsonite, and analcime. Natrolite only was found near to Siquirres. (Author) [Spanish] Se describen 19 especies diferentes de zeolitas procedentes de 25 afloramientos en los alrededores del Valle Central de Costa Rica y en la region de Siquirres. Todas las zeolitas descritas son de origen secundario y se presentan en vetillas y vesiculas de los basaltos y rocas piroclasticas de las formaciones La Cruz y Grifo Alto del Grupo Aguacate y en las rocas igneas alcalinas de Guayacan. Las especies mas frecuentes son estilbita, chabasita, laumontita, mesolita/modernita, thomsonita y analcima. La natrolita solo se encontro en los alrededores de Siquirres. (Autor)

Topography Battles Surface Texture: An Experimental Study of Pool-riffle Formation

Science.gov (United States)

Chartrand, S. M.; Hassan, M. A.; Jellinek, M.

2016-12-01

Pool-riffles are perhaps the most common streambed shape found in streams and rivers, and not surprisingly, they are essential to salmon ecology, and are a central focus of many restoration actions. Yet, when an applied earth scientist or engineer is faced with developing a pool-riffle design, there is a lack of clear and rigorously developed design guidelines. Given the volumes of money spent annually within the restoration industry, this is a real problem. Recognition of this problem is growing, however, and an increasing level of attention has been directed to questions of pool-riffle formation in the past decade. At this point and given certain landscape characteristics, it is well established that streamwise gradients in channel width are associated with pool-riffles. Specifically, pools are associated with negative gradients in width, and riffles with positive gradients. Importantly, these associations have now been documented from field-derived data, as well as via experimental and numerical investigations. There is much to build from the present knowledge base, and central to this are questions related to (a) how pool-riffles evolve during the formative process, (b) what are the basic set of ingredients necessary for pool-riffle formation within systems characterized by relatively non-erodible channel margins, and (c) do pool-riffles persist, once formed, under a broad range of forcing conditions? We have completed four physical experiments examining the process and evolution of pool-riffle formation under a large range of upstream boundary, as well as physical channel conditions. We will report on two of the completed experiments. Our work will highlight two new non-dimensional channel evolution numbers, derived to help describe and characterize bedform development, as well as response to perturbations from near-equilibrium conditions. The channel evolution numbers lay the foundation for development of a new regime diagram, which quantifies the basic

DAGMARITA SHHREZAENSIS N. SP. GLOBIVALVULINID FORAMINIFER, (WUCHIAPINGIAN, LATE PERMIAN, CENTRAL IRAN

Directory of Open Access Journals (Sweden)

PARVIN MOHTAT-AGHAI

2003-03-01

Full Text Available In the course of an investigation on the major mass extintion event near the P/T boundary, in the vicinity of Shahreza (South Isfahan in Iran, a stratigraphically significant new species of foraminifera (Dagmarita shahreaensis n. sp. has been discovered in the Wuchiapingian/Dzhulfian (Late Permian of central Iran (Hambast Formation. This new species is described and emplaced in the phylogeny of the globivalvulinid foraminifera, which evolved rapidly during the Middle/Late Permian. 

Nuclear legislation in Central and Eastern Europe and the NIS

CERN Document Server

2000-01-01

This publication examines the legislation and regulations governing the peaceful uses of nuclear energy in eastern European countries. It covers 11 countries from Central and Eastern Europe and 11 countries from the New Independent States. The chapters follow a systematic format making it easier for the reader to carry out research and compare information. This study will be updated regularly. Albania Kazakhstan Armenia Latvia Belarus Lithuania Bosnia and Herzegovina Poland Bulgaria Republic of Moldova Croatia Romania Czech Republic Russian Federation Estonia Slovak Republic Former Yugoslav Re

The contribution of formative assessment and self-efficacy to inquiry learning

DEFF Research Database (Denmark)

Dolin, Jens; Evans, Robert Harry

2013-01-01

This chapter suggests the use of formative assessment in inquiry lessons as a helpful source of positive personal capacity beliefs for both teachers and students. The challenge most commonly experienced when first using inquiry learning methods is that pupils and even teachers become uncertain...... of their abilities to use inquiry and ‘give-up’ on it. With the use of formative assessment combined with conscious efforts to increase self-efficacy among students, teachers can help provide students with the confidence and motivation to engage in inquiry methods. Such student engagement can in-turn affirm teachers......’ inquiry teaching efforts and raise the likelihood that they will continue to improve them. We see inquiry methods as the motor for changing teacher practice and formative assessment methods combined with capacity beliefs as the fuel that keeps the motor running. The central position of the chapter is how...

The Effect of Formative Testing and Self-Directed Learning on Mathematics Learning Outcomes

Science.gov (United States)

Sumantri, Mohamad Syarif; Satriani, Retni

2016-01-01

The purpose of this research was to determine the effect of formative testing and self-directed learning on mathematics learning outcomes. The research was conducted at an elementary school in central Jakarta during the 2014/2015 school year. Seventy-two fourth-grade students who were selected using random sampling participated in this study. Data…

LLAMA: normal star formation efficiencies of molecular gas in the centres of luminous Seyfert galaxies

Science.gov (United States)

Rosario, D. J.; Burtscher, L.; Davies, R. I.; Koss, M.; Ricci, C.; Lutz, D.; Riffel, R.; Alexander, D. M.; Genzel, R.; Hicks, E. H.; Lin, M.-Y.; Maciejewski, W.; Müller-Sánchez, F.; Orban de Xivry, G.; Riffel, R. A.; Schartmann, M.; Schawinski, K.; Schnorr-Müller, A.; Saintonge, A.; Shimizu, T.; Sternberg, A.; Storchi-Bergmann, T.; Sturm, E.; Tacconi, L.; Treister, E.; Veilleux, S.

2018-02-01

Using new Atacama Pathfinder Experiment and James Clerk Maxwell Telescope spectroscopy of the CO 2→1 line, we undertake a controlled study of cold molecular gas in moderately luminous (Lbol = 1043-44.5 erg s-1) active galactic nuclei (AGN) and inactive galaxies from the Luminous Local AGN with Matched Analogs (LLAMA) survey. We use spatially resolved infrared photometry of the LLAMA galaxies from 2MASS, the Wide-field Infrared Survey Explorer the Infrared Astronomical Satellite and the Herschel Space Observatory (Herschel), corrected for nuclear emission using multicomponent spectral energy distribution fits, to examine the dust-reprocessed star formation rates, molecular gas fractions and star formation efficiencies (SFEs) over their central 1-3 kpc. We find that the gas fractions and central SFEs of both active and inactive galaxies are similar when controlling for host stellar mass and morphology (Hubble type). The equivalent central molecular gas depletion times are consistent with the discs of normal spiral galaxies in the local Universe. Despite energetic arguments that the AGN in LLAMA should be capable of disrupting the observable cold molecular gas in their central environments, our results indicate that nuclear radiation only couples weakly with this phase. We find a mild preference for obscured AGN to contain higher amounts of central molecular gas, which suggests connection between AGN obscuration and the gaseous environment of the nucleus. Systems with depressed SFEs are not found among the LLAMA AGN. We speculate that the processes that sustain the collapse of molecular gas into dense pre-stellar cores may also be a prerequisite for the inflow of material on to AGN accretion discs.

Star-forming galaxy models: Blending star formation into TREESPH

Science.gov (United States)

Mihos, J. Christopher; Hernquist, Lars

1994-01-01

We have incorporated star-formation algorithms into a hybrid N-body/smoothed particle hydrodynamics code (TREESPH) in order to describe the star forming properties of disk galaxies over timescales of a few billion years. The models employ a Schmidt law of index n approximately 1.5 to calculate star-formation rates, and explicitly include the energy and metallicity feedback into the Interstellar Medium (ISM). Modeling the newly formed stellar population is achieved through the use of hybrid SPH/young star particles which gradually convert from gaseous to collisionless particles, avoiding the computational difficulties involved in creating new particles. The models are shown to reproduce well the star-forming properties of disk galaxies, such as the morphology, rate of star formation, and evolution of the global star-formation rate and disk gas content. As an example of the technique, we model an encounter between a disk galaxy and a small companion which gives rise to a ring galaxy reminiscent of the Cartwheel (AM 0035-35). The primary galaxy in this encounter experiences two phases of star forming activity: an initial period during the expansion of the ring, and a delayed phase as shocked material in the ring falls back into the central regions.

Monitoring pulsating giant stars in M33: star formation history and chemical enrichment

Science.gov (United States)

Javadi, A.; van Loon, J. Th

2017-06-01

We have conducted a near-infrared monitoring campaign at the UK InfraRed Telescope (UKIRT), of the Local Group spiral galaxy M33 (Triangulum). A new method has been developed by us to use pulsating giant stars to reconstruct the star formation history of galaxies over cosmological time as well as using them to map the dust production across their host galaxies. In first Instance the central square kiloparsec of M33 was monitored and long period variable stars (LPVs) were identified. We give evidence of two epochs of a star formation rate enhanced by a factor of a few. These stars are also important dust factories, we measure their dust production rates from a combination of our data with Spitzer Space Telescope mid-IR photometry. Then the monitoring survey was expanded to cover a much larger part of M33 including spiral arms. Here we present our methodology and describe results for the central square kiloparsec of M33 [1-4] and disc of M33 [5-8].

Monitoring pulsating giant stars in M33: star formation history and chemical enrichment

International Nuclear Information System (INIS)

Javadi, A; Van Loon, J Th

2017-01-01

We have conducted a near-infrared monitoring campaign at the UK InfraRed Telescope (UKIRT), of the Local Group spiral galaxy M33 (Triangulum). A new method has been developed by us to use pulsating giant stars to reconstruct the star formation history of galaxies over cosmological time as well as using them to map the dust production across their host galaxies. In first Instance the central square kiloparsec of M33 was monitored and long period variable stars (LPVs) were identified. We give evidence of two epochs of a star formation rate enhanced by a factor of a few. These stars are also important dust factories, we measure their dust production rates from a combination of our data with Spitzer Space Telescope mid-IR photometry. Then the monitoring survey was expanded to cover a much larger part of M33 including spiral arms. Here we present our methodology and describe results for the central square kiloparsec of M33 [1–4] and disc of M33 [5–8]. (paper)

CRA-1 uncovers a double-strand break-dependent pathway promoting the assembly of central region proteins on chromosome axes during C. elegans meiosis.

Science.gov (United States)

Smolikov, Sarit; Schild-Prüfert, Kristina; Colaiácovo, Mónica P

2008-06-06

The synaptonemal complex (SC), a tripartite proteinaceous structure that forms between homologous chromosomes during meiosis, is crucial for faithful chromosome segregation. Here we identify CRA-1, a novel and conserved protein that is required for the assembly of the central region of the SC during C. elegans meiosis. In the absence of CRA-1, central region components fail to extensively localize onto chromosomes at early prophase and instead mostly surround the chromatin at this stage. Later in prophase, central region proteins polymerize along chromosome axes, but for the most part fail to connect the axes of paired homologous chromosomes. This defect results in an inability to stabilize homologous pairing interactions, altered double-strand break (DSB) repair progression, and a lack of chiasmata. Surprisingly, DSB formation and repair are required to promote the polymerization of the central region components along meiotic chromosome axes in cra-1 mutants. In the absence of both CRA-1 and any one of the C. elegans homologs of SPO11, MRE11, RAD51, or MSH5, the polymerization observed along chromosome axes is perturbed, resulting in the formation of aggregates of the SC central region proteins. While radiation-induced DSBs rescue this polymerization in cra-1; spo-11 mutants, they fail to do so in cra-1; mre-11, cra-1; rad-51, and cra-1; msh-5 mutants. Taken together, our studies place CRA-1 as a key component in promoting the assembly of a tripartite SC structure. Moreover, they reveal a scenario in which DSB formation and repair can drive the polymerization of SC components along chromosome axes in C. elegans.

Protracted fluid-induced melting during Barrovian metamorphism in the Central Alps

DEFF Research Database (Denmark)

Rubatto, Daniela; Hermann, Jörg; Berger, Alfons

2009-01-01

that repeated melting events occurred within a single Barrovian metamorphic cycle at roughly constant temperature; that in the country rocks zircon formation was limited to the initial stages of melting, whereas further melting concentrated in the segregated leucosomes; that melting occurred at different times......The timing and dynamics of fluid-induced melting in the typical Barrovian sequence of the Central Alps has been investigated using zircon chronology and trace element composition. Multiple zircon domains in leucosomes and country rocks yield U-Pb ages spanning from ~32 to 22 Ma. The zircon formed...... in samples a few meters apart because of the local rock composition and localized influx of the fluids; and that leucosomes were repeatedly melted when fluids became available. The geochronological data force a revision of the temperature-time path of the migmatite belt in the Central Alps. Protracted...

Star-formation complexes in the `galaxy-sized' supergiant shell of the galaxy Holmberg I

Science.gov (United States)

Egorov, Oleg V.; Lozinskaya, Tatiana A.; Moiseev, Alexei V.; Smirnov-Pinchukov, Grigory V.

2018-05-01

We present the results of observations of the galaxy Holmberg I carried out at the Russian 6-m telescope in the narrow-band imaging, long-slit spectroscopy, and scanning Fabry-Perot interferometer modes. A detailed analysis of gas kinematics, ionization conditions, and metallicity of star-forming regions in the galaxy is presented. The aim of the paper is to analyse the propagation of star formation in the galaxy and to understand the role of the ongoing star formation in the evolution of the central `galaxy-sized' supergiant H I shell (SGS), where all regions of star formation are observed. We show that star formation in the galaxy occurs in large unified complexes rather than in individual giant H II regions. Evidence of the triggered star formation is observed both on scales of individual complexes and of the whole galaxy. We identified two supernova-remnant candidates and one late-type WN star and analysed their spectrum and surrounding-gas kinematics. We provide arguments indicating that the SGS in Holmberg I is destructing by the influence of star formation occurring on its rims.

Impact of short-term hemodialysis catheters on the central veins: a catheter venographic study

Energy Technology Data Exchange (ETDEWEB)

Oguzkurt, Levent E-mail: loguzkurt@yahoo.com; Tercan, Fahri; Torun, Dilek; Yildirim, Tuelin; Zuemruetdal, Ayseguel; Kizilkilic, Osman

2004-12-01

Objective: To determine the incidence of pericatheter sleeve formation, thrombus formation, and stenosis of the central veins in hemodialysis patients with temporary catheters. Methods and material: In this prospective study, 57 patients (40 males, 17 females) with temporary dialysis catheters had catheter venography by pulling back the catheter just before removal. Patient's age range was 25-87 years (mean age, 51 years). The venographic studies were evaluated for pericatheter sleeve formation, thrombus formation, and stenosis of the brachiocephalic vein (BCV) and the superior vena cava (SVC). The IJV could only be evaluated if there was adequate filling during contrast administration. In a subgroup of patients who had had only right IJV or only right SCV catheters, impact of these catheters on the central veins was compared. Results: The catheter location was right internal jugular vein (IJV) in 26 cases, right subclavian vein (SCV) in 27 cases, left IJV in 1 case, and left SCV in 3 cases. Thirty-two patients (56%) had had only one temporary catheter and the rest had had more than one inserted. The mean dwell time for the catheters was 21 days (range 7-59 days). A pericatheter sleeve was detected on venography in 32 (56%) patients and thrombus formation was noted in 16 patients (28%). A total of 41 patients (72%) exhibited pericatheter sleeve and/or thrombus formation. While 19 of the 32 patients (59%) without previous catheterization had a sleeve around the catheter, only 13 (52%) of 25 patients who had had multiple catheters inserted had a sleeve (P>0.05). Of the eight patients (14%) with BCV stenosis, two had >50% stenosis. Only one patient (2%) had mild stenosis of the SVC. Three patients out of 15 (20%) who had diagnostic venography for the IJV had severe stenosis of the vein. Pericatheter sleeve formation was more frequent in women (P<0.05). However, there were no statistical differences with respect to pericatheter sleeve formation, luminal filling

THE FORMATION OF IRIS DIAGNOSTICS. II. THE FORMATION OF THE Mg II h and k LINES IN THE SOLAR ATMOSPHERE

Energy Technology Data Exchange (ETDEWEB)

Leenaarts, J.; Pereira, T. M. D.; Carlsson, M.; De Pontieu, B. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Uitenbroek, H., E-mail: jorritl@astro.uio.no, E-mail: tiago.pereira@astro.uio.no, E-mail: mats.carlsson@astro.uio.no, E-mail: bdp@lmsal.com, E-mail: huitenbroek@nso.edu [NSO/Sacramento Peak P.O. Box 62 Sunspot, NM 88349-0062 (United States)

2013-08-01

NASA's Interface Region Imaging Spectrograph (IRIS) small explorer mission will study how the solar atmosphere is energized. IRIS contains an imaging spectrograph that covers the Mg II h and k lines as well as a slit-jaw imager centered at Mg II k. Understanding the observations requires forward modeling of Mg II h and k line formation from three-dimensional (3D) radiation-magnetohydrodynamic (RMHD) models. This paper is the second in a series where we undertake this modeling. We compute the vertically emergent h and k intensity from a snapshot of a dynamic 3D RMHD model of the solar atmosphere, and investigate which diagnostic information about the atmosphere is contained in the synthetic line profiles. We find that the Doppler shift of the central line depression correlates strongly with the vertical velocity at optical depth unity, which is typically located less than 200 km below the transition region (TR). By combining the Doppler shifts of the h and k lines we can retrieve the sign of the velocity gradient just below the TR. The intensity in the central line depression is anti-correlated with the formation height, especially in subfields of a few square Mm. This intensity could thus be used to measure the spatial variation of the height of the TR. The intensity in the line-core emission peaks correlates with the temperature at its formation height, especially for strong emission peaks. The peaks can thus be exploited as a temperature diagnostic. The wavelength difference between the blue and red peaks provides a diagnostic of the velocity gradients in the upper chromosphere. The intensity ratio of the blue and red peaks correlates strongly with the average velocity in the upper chromosphere. We conclude that the Mg II h and k lines are excellent probes of the very upper chromosphere just below the TR, a height regime that is impossible to probe with other spectral lines. They also provide decent temperature and velocity diagnostics of the middle

Geology and uranium occurrences in the Forez tertiary plain (in the French 'Massif Central'); Geologie et mineralisations uraniferes de la plaine tertiaire du Forez (Massif Central francais)

Energy Technology Data Exchange (ETDEWEB)

Duclos, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses - 92 (France). Centre d' Etudes Nucleaires

1967-01-01

In the first part, the observations made during the geological survey of the Forez Tertiary plain (in the French 'Massif Central') are recalled. Then, using various methods, the author lists the formations according to chronology. Finally, a reconstitution of the geological history of this subsidence basin is attempted. In the second part, the occurrence of 17 uranium bearing geochemical anomalies is commented upon. Each of these various anomalies is given a place on the stratigraphic scale. This enables the author to put the successive phases of uranium deposition into their proper perspective in the history of the plain. In conclusion, the author points out the usefulness of these uraniferous geochemical anomalies. (author) [French] Dans la premiere partie, l'auteur rappelle les observations faites au cours de l'etude geologique de la plaine tertiaire du Forez (Massif Central francais). Puis se servant de differentes methodes, il etablit une chronologie des formations. Enfin, il termine par un essai de reconstitution de l'histoire geologique de ce bassin de subsidence. Dans la deuxieme partie, il commente la decouverte de 17 anomalies geochimiques uraniferes. Il situe ces differentes anomalies dans la serie stratigraphique. Ceci lui permet de replacer les depots successifs de l'uranium dans l'histoire de la plaine. Enfin, il indique l'interet de ces anomalies geochimiques uraniferes. (auteur)

Geospatial database for regional environmental assessment of central Colorado.

Science.gov (United States)

Church, Stan E.; San Juan, Carma A.; Fey, David L.; Schmidt, Travis S.; Klein, Terry L.; DeWitt, Ed H.; Wanty, Richard B.; Verplanck, Philip L.; Mitchell, Katharine A.; Adams, Monique G.; Choate, LaDonna M.; Todorov, Todor I.; Rockwell, Barnaby W.; McEachron, Luke; Anthony, Michael W.

2012-01-01

In conjunction with the future planning needs of the U.S. Department of Agriculture, Forest Service, the U.S. Geological Survey conducted a detailed environmental assessment of the effects of historical mining on Forest Service lands in central Colorado. Stream sediment, macroinvertebrate, and various filtered and unfiltered water quality samples were collected during low-flow over a four-year period from 2004–2007. This report summarizes the sampling strategy, data collection, and analyses performed on these samples. The data are presented in Geographic Information System, Microsoft Excel, and comma-delimited formats. Reports on data interpretation are being prepared separately.

Formation of a Boundary-Free Dust Cluster in a Low-Pressure Gas-Discharge Plasma

International Nuclear Information System (INIS)

Usachev, A. D.; Zobnin, A. V.; Petrov, O. F.; Fortov, V. E.; Annaratone, B. M.; Thoma, M. H.; Hoefner, H.; Kretschmer, M.; Fink, M.; Morfill, G. E.

2009-01-01

An attraction between negatively charged micron-sized plastic particles was observed in the bulk of a low-pressure gas-discharge plasma under microgravity conditions. This attraction had led to the formation of a boundary-free dust cluster, containing one big central particle with a radius of about 6 μm and about 30 1 μm-sized particles situated on a sphere with a radius of 190 μm and with the big particle in the center. The stability of this boundary-free dust cluster was possible due to its confinement by the plasma flux on the central dust particle

Variations of current profiles in tokamaks. Formation mechanism and confinement property of current-hole configuration

International Nuclear Information System (INIS)

Takizuka, Tomonori

2003-01-01

The formation mechanism of the current hole in tokamak plasmas is reviewed. Experimental results of JT-60U are shown. Increase of the off-central noninductive current is a key factor for the current-hole formation. The internal Transport Barrier (ITB), which generates large bootstrap current, plays an important role. The central current density in the hole stays nearly 0. The idea of a new equilibrium for a tokamak plasma with a current hole is introduced. This equilibrium configuration called Axisymmetric Tri-Magnetic-Islands (ATMI) equilibrium', has three islands along the R direction (a central-negative-current island and side-positive-current islands). The equilibrium is stable with the elongation coils when the current in the ATMI region is limited to a small amount. The confinement properties of a current-hole configuration with box-type ITB is described. A scaling of the core poloidal beta inside the ITB, β p,core , is given as ε f β p,core approx. = 1, which suggests the equilibrium limit (ε f : inverse aspect ratio at the ITB foot). Though the core stored energy is little dependent on the heating power, the estimated heat diffusivity in the ITB region moderately correlates with a neoclassical diffusivity. (author)

Paleomagnetic and geochronologic constraints on the geodynamic evolution of the Central Dinarides

Science.gov (United States)

de Leeuw, Arjan; Mandic, Oleg; Krijgsman, Wout; Kuiper, Klaudia; Hrvatović, Hazim

2013-04-01

The geodynamic evolution of the Dinaride Mountains of southeastern Europe is relatively poorly understood, especially in comparison with the neighbouring Alps and Carpathians. We have constructed a new chronostratigraphy for the post-orogenic intra-montane basins of the Central Dinarides based on paleomagnetic and 40Ar/39Ar age data. Our results provide time constraints on the formation of these basins and elucidate their subsequent evolution. This is a fundamental step towards a better understanding of the late stage geodynamic evolution of the Central Dinarides. Our paleomagnetic results moreover indicate that the Dinarides have not experienced significant tectonic rotation since the late Oligocene. This implies that the Dinarides were decoupled from the adjacent Adria and the Tisza-Dacia Mega-Units that both underwent major rotation. We provide a reference frame for our rotation results through a review of Late Jurassic to Miocene paleomagnetic data, which elucidates spatial and tectonic rotation patterns in the Adria-Dinarides collision zone. The obtained results significantly improve our insight in the evolution of the Central Dinarides and help reconcile structural geological and paleomagnetic rotation estimates.

DISK FORMATION IN MAGNETIZED CLOUDS ENABLED BY THE HALL EFFECT

International Nuclear Information System (INIS)

Krasnopolsky, Ruben; Shang, Hsien; Li Zhiyun

2011-01-01

Stars form in dense cores of molecular clouds that are observed to be significantly magnetized. A dynamically important magnetic field presents a significant obstacle to the formation of protostellar disks. Recent studies have shown that magnetic braking is strong enough to suppress the formation of rotationally supported disks in the ideal MHD limit. Whether non-ideal MHD effects can enable disk formation remains unsettled. We carry out a first study on how disk formation in magnetic clouds is modified by the Hall effect, the least explored of the three non-ideal MHD effects in star formation (the other two being ambipolar diffusion and Ohmic dissipation). For illustrative purposes, we consider a simplified problem of a non-self-gravitating, magnetized envelope collapsing onto a central protostar of fixed mass. We find that the Hall effect can spin up the inner part of the collapsing flow to Keplerian speed, producing a rotationally supported disk. The disk is generated through a Hall-induced magnetic torque. Disk formation occurs even when the envelope is initially non-rotating, provided that the Hall coefficient is large enough. When the magnetic field orientation is flipped, the direction of disk rotation is reversed as well. The implication is that the Hall effect can in principle produce both regularly rotating and counter-rotating disks around protostars. The Hall coefficient expected in dense cores is about one order of magnitude smaller than that needed for efficient spin-up in these models. We conclude that the Hall effect is an important factor to consider in studying the angular momentum evolution of magnetized star formation in general and disk formation in particular.

High diversity and morphological convergence among melanised fungi from rock formations in the Central Mountain System of Spain

NARCIS (Netherlands)

Ruibal, C.; Platas, G.; Bills, G.F.

2008-01-01

Melanised fungi were isolated from rock surfaces in the Central Mountain System of Spain. Two hundred sixty six isolates were recovered from four geologically and topographically distinct sites. Microsatellite-primed PCR techniques were used to group isolates into genotypes assumed to represent

Densities and Kinematic Viscosities for the Systems Benzene + Methyl Formate, Benzene + Ethyl Formate, Benzene + Propyl Formate, and Benzene + Butyl Formate

DEFF Research Database (Denmark)

Emmerling, Uwe; Rasmussen, Peter

1998-01-01

a Redlich-Kister type of expression with temperature-independent parameters and the data for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate with temperature-dependent parameters. The viscosities have furthermore been compared to values predicted by means of the GC......Densities and kinematic viscosities have been measured for the system benzene + methyl formate at 20°C and for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate from 20°C to 50°C. The results for the system benzene + methyl formate have been correlated using...

Coraco- or Costoclavicular Paraosteoarthropathies in Patients with Severe Central Neurological Disorders

International Nuclear Information System (INIS)

Lacout, A.; Mompoint, D.; Perrier, Y.; Vallee, C.A.; Carlier, R.Y.

2008-01-01

Background: Paraosteoarthropathy (POA) is a frequent disabling orthopedic complication after severe central neurological impairment. The hip is the most frequently affected joint (32.1%) followed by the elbow and the shoulder (25%). Purpose: To evaluate coraco- and costoclavicular paraosteoarthropathy in patients with severe central neurological disorders. Material and Methods: We report a series of five consecutive patients with severe central neurological disorders who developed a POA of the clavicular region (coracoclavicular or costoclavicular POA). Every patient underwent a clinical, radiological, and computed tomographic (CT) examination of the shoulder region. Results: Four patients had a history of traumatic brain injury (TBI), and one an acute disseminated encephalomyelitis (ADEM). They developed POA of the clavicular region, although not around the glenohumeral joint. The patients complained of shoulder pain and of moderate limitation of movements. Radiological and CT examinations showed the presence of a bony formation in the coracoclavicular space in four cases and extending from the clavicle to the first rib around the costoclavicular joint in one case. Conclusion: In patients with severe brain lesions suffering from shoulder pain and moderate limitation of joint movements, POAs of the clavicular region are rare but should be considered

Olfactory memory formation in Drosophila: from molecular to systems neuroscience.

Science.gov (United States)

Davis, Ronald L

2005-01-01

The olfactory nervous system of insects and mammals exhibits many similarities, which suggests that the mechanisms for olfactory learning may be shared. Molecular genetic investigations of Drosophila learning have uncovered numerous genes whose gene products are essential for olfactory memory formation. Recent studies of the products of these genes have continued to expand the range of molecular processes known to underlie memory formation. Recent research has also broadened the neuroanatomical areas thought to mediate olfactory learning to include the antennal lobes in addition to a previously accepted and central role for the mushroom bodies. The roles for neurons extrinsic to the mushroom body neurons are becoming better defined. Finally, the genes identified to participate in Drosophila olfactory learning have conserved roles in mammalian organisms, highlighting the value of Drosophila for gene discovery.

Galaxy collisions as a mechanism of ultra diffuse galaxy (UDG) formation

Science.gov (United States)

Baushev, A. N.

2018-04-01

We suggest a possible mechanism of ultra diffuse galaxy formation: the UDGs may occur as a result of a central collision of galaxies. If the galaxies are young and contain a lot of gas, the collision may kick all the gas off the systems and thus strongly suppress any further star formation. As a result, the galaxies now have a very low surface brightness and other properties typical of the ultra diffuse galaxies. We use the Coma cluster (where numerous UDGs were recently discovered) to test the efficiency of the process. The mechanism works very well and can transform a significant fraction of the cluster population into ultra diffuse galaxies. The UDGs formed by the process concentrate towards the center of the cluster, and their globular cluster systems remain undamaged, in accordance with observational results. The projected surface density of UDGs in the cluster may help us to recognize the mechanism of UDG formation, or clarify relative contributions of several possible competitive mechanisms at work.

Ghrelin: Central and Peripheral Implications in Anorexia Nervosa

Directory of Open Access Journals (Sweden)

Mathieu eMéquinion

2013-02-01

Full Text Available Food intake and associated disorders are gaining large emphasis in our societies due to their dramatic physiological and psychological consequences on health. Chronic food restriction is a major symptom described in restrictive anorexia nervosa (AN patients. This disease, mostly observed in young women is the third cause of chronic illness in teenagers. It leads to central and/or peripheral reprogramming that permits the organism to endure the reduced energy supplies. These drastic conditions induce severe weight loss, metabolic disturbances, infertility, osteopenia and osteoporosis. Moreover, increasing number of arguments consider AN as an addictive behaviour to food deprivation or weight loss or physical activity, usually associated with mood disorders. This suggests a potential alteration of the central reward system. Significant changes in hormones involved in energy metabolism, regulation of feeding behaviours and bone formation are described in AN patients, but also in animal models presenting a strong face validity. Surprisingly, the plasma levels of ghrelin, an orexigenic hormone, are increased. This hormone acts centrally to modulate food intake, but also peripherally mainly to maintain blood glucose and to regulate gastric motility. Such increase in plasma ghrelin levels seems paradoxical in light of the restrained eating adopted by these AN patients, but adaptive. The aim of this review is to describe the role played by ghrelin in AN focusing on its central vs peripheral action. The chronic food restriction induces both in AN patients and in rodent models a profound alteration in the « ghrelin » signal integration that lead to the development of inappropriate behaviours like hyperactivity or addiction to food starvation and therefore a greater depletion in energy reserves. The question of a transient insensitivity to ghrelin and/or a potential metabolic reprogramming is discussed in regard of new clinical treatments currently

Age of depositional and weathering events in Central Amazonia

Science.gov (United States)

Sant'Anna, Lucy Gomes; Soares, Emílio Alberto do Amaral; Riccomini, Claudio; Tatumi, Sonia Hatsue; Yee, Marcio

2017-08-01

In the last three decades, several studies have been devoted to understanding the role of Late Pleistocene-Holocene climate changes in the Amazonia lowlands environment. However, most of these studies used data obtained from sedimentary deposits (lakes, swamps, and colluvium) located away from the central plain or on the edges of the Amazonia region. This article integrates optically stimulated luminescence and accelerated mass spectrometry 14C ages with sedimentological and geomorphological data obtained during this study or compiled from the literature for fluvial and lacustrine deposits of the central alluvial plain of the Solimões-Amazon River. The age data allow us to present a chronological framework for the Late Pleistocene-Holocene deposits and conclude that (i) the dryness of the LGM in central Amazonia lowlands is recorded by the formation of fluvial terraces and their weathering to pedogenic hematite between 25.3 ka and 17.7 ka; (ii) floodplain deposition was contemporaneous with terrace weathering and occurred in a context of decreased water volume in fluvial channels, lowering of river base level and sea level, and isostatic rebound of the continent; and (iii) lateral and mid-channel fluvial bars in the Solimões-Amazon River have a minimum age of 11.5 ± 1.5 ka, and their deposition responded to increased precipitation at the beginning of the Holocene.

Radiologic Placement of Tunneled Central Venous Catheters in Pediatric Patients

International Nuclear Information System (INIS)

Kim, Eun Ji; Song, Soon Young; Cho, On Koo; Koh, Byung Hee; Kim, Yong Soo; Jeong, Woo Kyoung; Lee, Yong Ho

2010-01-01

We evaluated the technical success and complication rates associated with the radiological placement of tunneled central venous catheters in pediatric patients. Between May 1, 2005 and March 31, 2008, a total of 46 tunneled central venous catheters were placed in 34 children (M:F = 22:12; mean age, 9.9 years [9 months to 16.8 years]). All procedures were performed under ultrasonographic and fluoroscopic guidance. Follow-up data were obtained through the retrospective review of the medical records. We used the Kaplan-Meier survival method for the evaluation of survival rate of the catheters. All procedures were technically successful. The observed periprocedural complications included hematoma formation in three patients. The mean catheter life was 189.3 days (total, 8710 days; range, 7-810). Catheters were removed due to death (n=9), the end of treatment (n=8), catheter sepsis (n=4), malfunction (n=8), and accidental removal (n=4). The rate of catheter sepsis and malfunction was 0.459 and 0.919 for every 1000 catheter days, respectively. The expected mean catheter life was 479.6 days as per the Kaplan- Meier analysis. The results suggest that the radiologic placement of a tunneled central venous catheter is an effective technique with a high technical success rate and low complication rate

Radiologic Placement of Tunneled Central Venous Catheters in Pediatric Patients

Energy Technology Data Exchange (ETDEWEB)

Kim, Eun Ji; Song, Soon Young; Cho, On Koo; Koh, Byung Hee; Kim, Yong Soo; Jeong, Woo Kyoung; Lee, Yong Ho [Hanyang University College of Medicine, Seoul (Korea, Republic of)

2010-08-15

We evaluated the technical success and complication rates associated with the radiological placement of tunneled central venous catheters in pediatric patients. Between May 1, 2005 and March 31, 2008, a total of 46 tunneled central venous catheters were placed in 34 children (M:F = 22:12; mean age, 9.9 years [9 months to 16.8 years]). All procedures were performed under ultrasonographic and fluoroscopic guidance. Follow-up data were obtained through the retrospective review of the medical records. We used the Kaplan-Meier survival method for the evaluation of survival rate of the catheters. All procedures were technically successful. The observed periprocedural complications included hematoma formation in three patients. The mean catheter life was 189.3 days (total, 8710 days; range, 7-810). Catheters were removed due to death (n=9), the end of treatment (n=8), catheter sepsis (n=4), malfunction (n=8), and accidental removal (n=4). The rate of catheter sepsis and malfunction was 0.459 and 0.919 for every 1000 catheter days, respectively. The expected mean catheter life was 479.6 days as per the Kaplan- Meier analysis. The results suggest that the radiologic placement of a tunneled central venous catheter is an effective technique with a high technical success rate and low complication rate.

Air-liquid biofilm formation is dependent on ammonium depletion in a Saccharomyces cerevisiae flor strain.

Science.gov (United States)

Zara, Giacomo; Budroni, Marilena; Mannazzu, Ilaria; Zara, Severino

2011-12-01

Air-liquid biofilm formation appears to be an adaptive mechanism that promotes foraging of Saccharomyces cerevisiae flor strains in response to nutrient starvation. The FLO11 gene plays a central role in this phenotype as its expression allows yeast cells to rise to the liquid surface. Here, we investigated the role of ammonium depletion in air-liquid biofilm formation and FLO11 expression in a S. cerevisiae flor strain. The data obtained show that increasing ammonium concentrations from 0 to 450 m m reduce air-liquid biofilm in terms of biomass and velum formation and correlate with a reduction of FLO11 expression. Rapamycin inhibition of the TOR pathway and deletion of RAS2 gene significantly reduced biofilm formation and FLO11 expression. Taken together, these data suggest that ammonium depletion is a key factor in the induction of air-liquid biofilm formation and FLO11 expression in S. cerevisiae flor strains. Copyright © 2011 John Wiley & Sons, Ltd.

Nucleotide synthesis is regulated by cytoophidium formation during neurodevelopment and adaptive metabolism

Directory of Open Access Journals (Sweden)

Gabriel N. Aughey

2014-10-01

Full Text Available The essential metabolic enzyme CTP synthase (CTPsyn can be compartmentalised to form an evolutionarily-conserved intracellular structure termed the cytoophidium. Recently, it has been demonstrated that the enzymatic activity of CTPsyn is attenuated by incorporation into cytoophidia in bacteria and yeast cells. Here we demonstrate that CTPsyn is regulated in a similar manner in Drosophila tissues in vivo. We show that cytoophidium formation occurs during nutrient deprivation in cultured cells, as well as in quiescent and starved neuroblasts of the Drosophila larval central nervous system. We also show that cytoophidia formation is reversible during neurogenesis, indicating that filament formation regulates pyrimidine synthesis in a normal developmental context. Furthermore, our global metabolic profiling demonstrates that CTPsyn overexpression does not significantly alter CTPsyn-related enzymatic activity, suggesting that cytoophidium formation facilitates metabolic stabilisation. In addition, we show that overexpression of CTPsyn only results in moderate increase of CTP pool in human stable cell lines. Together, our study provides experimental evidence, and a mathematical model, for the hypothesis that inactive CTPsyn is incorporated into cytoophidia.

The Cognitive Limits to Economic Cluster Formation

Directory of Open Access Journals (Sweden)

Michael C. Carrol

2012-01-01

Full Text Available There has been increasing interest in the social dimensions of economic clusters. The literature now includes select examples of social network analysis plus an extensive discussion of learning regions. Unfortunately, much of this work treats the network as the primary unit of analysis. It may be that network attributes such as density, centrality, and power are primarily dependent on human limitations and not instituted factors. In other words, a human’s limited ability to process information may be a better determinant of cluster success than economic or network theory. The purpose of this paper is to highlight human limits in cluster formation. To do this, we draw on recent developments in the cognitive psychology and communications literatures. We explain that many of the factors that lead to underperforming cluster policies are the result of a human’s inability to develop and sustain a large number of social interactions. Any cluster policy must be cognizant of such limitations and carefully address these limits in the formation of the initial strategy.

The Novel Formation of Barium Titanate Nanodendrites

Directory of Open Access Journals (Sweden)

Chien-Jung Huang

2014-01-01

Full Text Available The barium titanate (BaTiO3 nanoparticles with novel dendrite-like structures have been successfully fabricated via a simple coprecipitation method, the so-called BaTiO3 nanodendrites (BTNDs. This method was remarkable, fast, simple, and scalable. The growth solution is prepared by barium chloride (BaCl2, titanium tetrachloride (TiCl4, and oxalic acid. The shape and size of BaTiO3 depend on the amount of added BaCl2 solvent. To investigate the influence of amount of BaCl2 on BTNDs, the amount of BaCl2 was varied in the range from 3 to 6 mL. The role of BaCl2 is found to have remarkable influence on the morphology, crystallite size, and formation of dendrite-like structures. The thickness and length of the central stem of BTND were ~300 nm and ~20 μm, respectively. The branchings were found to occur at irregular intervals along the main stem. Besides, the formation mechanism of BTND is proposed and discussed.

Galactic spiral arms formed by central explosions

International Nuclear Information System (INIS)

Havnes, O.

1978-01-01

Calculations have been made of spiral arm formation due to central explosions in a nucleus surrounded by a disc containing most of the galactic mass with the purpose of obtaining estimates on lifetimes of arms and the requirements on the energy involved in the process. The ejected gas is taken to be a few percent, or less, of the central nucleus and is ejected with velocities of the order of 1000 km s -1 . The gas, considered to be in forms of blobs, moves under the gravitational force from the disc and the nucleus and the drag force by the gas in the disc. The orbits of the blobs evolve towards the circular orbits of the disc due to this drag force and the velocities in the arms will therefore, after some time, approach those of a normal rotation curve. A relatively open structure will last 8 years. Stable ring structures with longer lifetimes may be formed by some explosions. With an energy of approximately 5 x 10 57 erg in the initial gas-blob motion and a duration of the explosion of approximately 10 7 years, the energy output in such explosions has to be > 10 43 erg s -1 . (Auth.)

Preliminary report on the geology of uranium deposits in the Browns Park Formation in Moffat County, Colorado, and Carbon County, Wyoming

International Nuclear Information System (INIS)

Ormond, A.

1957-06-01

Uranium was first discovered in the Browns Park Formation in 1951 in the Miller Hill area of south-central Wyoming. Since that time economically important deposits in this formation have been discovered and developed in the Poison Basin of south-central Wyoming and in the Maybell area of northwest Colorado. The Browns Park is the youngest formation (Miocene) in the region and overlies older rocks with angular unconformity. The formation consists of a basal conglomerate, fluviatile, lacustrine, and eolian sandstones, and locally a few thin beds of clay, tuff, and algal limestone. The sandstones are predominantly fine- to medium-grained and consist of quartz grains, scattered black chert grains, and interstitial clay. The uranium deposits are of the sandstone-impregnation type and are not confined to specific stratigraphic horizons. The important ore minerals are autunite and uranophane in oxidized sandstones, and uraninite and coffinite in unoxidized sandstones. Uranium is often associated with limonite and calcium carbonate in concretionary forms. Woody material, thought to play an important part in the deposition of uranium in many sandstone-type deposits, is not present in the deposits of the Browns Park Formation. However, organic carbon in the form of petroleum and petroleum residues has been observed in association with uranium in both the Poison Basin and the Maybell areas

Verbal and numerical consumer recommendations: switching between recommendation formats leads to preference inconsistencies.

Science.gov (United States)

Maciejovsky, Boris; Budescu, David V

2013-06-01

Many Web sites provide consumers with product recommendations, which are typically presented by a sequence of verbal reviews and numerical ratings. In three experiments, we demonstrate that when participants switch between formats (e.g., from verbal to numerical), they are more prone to preference inconsistencies than when they aggregate the recommendations within the same format (e.g., verbal). When evaluating recommendations, participants rely primarily on central-location measures (e.g., mean) and less on other distribution characteristics (e.g., variance). We explain our findings within the theoretical framework of stimulus-response compatibility and we make practical recommendations for the design of recommendation systems and Web portals.

Water Resources of Tajikistan and Water Use Issues in Central Asia

Directory of Open Access Journals (Sweden)

H. M. Mukhabbatov

2016-01-01

Full Text Available This paper investigates the formation and use of water resources in Tajikistan. The natural and geographic conditions as well as distribution of water resources across the economic regions are analyzed. It is stressed that after breakup of the Soviet Union the water use issues in Central Asia have acquired the dimensions of the interstate economic and political problems. Demographic growth, activation of desertification, global warming make most relevant the issue of equitable redistribution of water resources as the most valuable resource for economy.

Zeolites of the Valle Central of Costa Rica and its outskirts

International Nuclear Information System (INIS)

Zeledon, Luis Alonso

2004-01-01

19 different species of zeolites have been found in 25 outcrops in the Valle Central of Costa Rica and in the Siquirres region. All the zeolites are secondary minerals and crystallized in little veins and vesicles of the basalts and pyroclastics rocks of the La Cruz and Grifo Alto formations, belonging to the Aguacate Group and the alkaline igneous rocks of Guayacan. The most frequent species of zeolites are stibnite, chabasite, laumontite, mesolite/mordenite, thomsonite, and analcime. Natrolite only was found near to Siquirres. (Author) [es

Alignment between Satellite and Central Galaxies in the SDSS DR7: Dependence on Large-scale Environment

Science.gov (United States)

Wang, Peng; Luo, Yu; Kang, Xi; Libeskind, Noam I.; Wang, Lei; Zhang, Youcai; Tempel, Elmo; Guo, Quan

2018-06-01

The alignment between satellites and central galaxies has been studied in detail both in observational and theoretical works. The widely accepted fact is that satellites preferentially reside along the major axis of their central galaxy. However, the origin and large-scale environmental dependence of this alignment are still unknown. In an attempt to determine these variables, we use data constructed from Sloan Digital Sky Survey DR7 to investigate the large-scale environmental dependence of this alignment with emphasis on examining the alignment’s dependence on the color of the central galaxy. We find a very strong large-scale environmental dependence of the satellite–central alignment (SCA) in groups with blue centrals. Satellites of blue centrals in knots are preferentially located perpendicular to the major axes of the centrals, and the alignment angle decreases with environment, namely, when going from knots to voids. The alignment angle strongly depends on the {}0.1(g-r) color of centrals. We suggest that the SCA is the result of a competition between satellite accretion within large-scale structure (LSS) and galaxy evolution inside host halos. For groups containing red central galaxies, the SCA is mainly determined by the evolution effect, while for blue central dominated groups, the effect of the LSS plays a more important role, especially in knots. Our results provide an explanation for how the SCA forms within different large-scale environments. The perpendicular case in groups and knots with blue centrals may also provide insight into understanding similar polar arrangements, such as the formation of the Milky Way and Centaurus A’s satellite system.

Knowledge Cluster Formation as a Science Policy in Malaysia: Lessons Learned

OpenAIRE

Hans-Dieter Evers; ZEF University of Bonn; Solvay Gerke; Centre for Development Research, University of Bonn

2015-01-01

Regional science policy aims to create productive knowledge clusters, which are central places within an epistemic landscape of knowledge production and dissemination. These so-called K-clusters are said to have the organisational capability to drive innovations and create new industries. Many governments have used cluster formation as one of their development strategies. This paper looks at Malaysia's path towards a knowledge-based economy and offers some evidence on the current state of kno...

The occurrence of a shallow-water Ammobaculoides assemblage in the Middle Jurassic (Bajocian) Dhruma Formation of Central Saudi Arabia

Science.gov (United States)

Kaminski, Michael A.; Hammad Malik, Muhammad; Setoyama, Eiichi

2018-01-01

We report the occurrence of an Ammobaculoides-dominated assemblage in the lowermost member of the Middle Jurassic Dhruma Formation exposed west of Riyadh, Saudi Arabia. The new species Ammobaculoides dhrumaensis n.sp. is described from the green shale of the D1 unit (also known as the Balum Member) of the Dhruma Formation, which has been assigned an early Bajocian age based on ammonites. Our new finding constitutes the oldest reported worldwide occurrence of the agglutinated foraminiferal genus Ammobaculoides Plummer, 1932.

BolA Is Required for the Accurate Regulation of c-di-GMP, a Central Player in Biofilm Formation.

Science.gov (United States)

Moreira, Ricardo N; Dressaire, Clémentine; Barahona, Susana; Galego, Lisete; Kaever, Volkhard; Jenal, Urs; Arraiano, Cecília M

2017-09-19

The bacterial second messenger cyclic dimeric GMP (c-di-GMP) is a nearly ubiquitous intracellular signaling molecule involved in the transition from the motile to the sessile/biofilm state in bacteria. C-di-GMP regulates various cellular processes, including biofilm formation, motility, and virulence. BolA is a transcription factor that promotes survival in different stresses and is also involved in biofilm formation. Both BolA and c-di-GMP participate in the regulation of motility mechanisms leading to similar phenotypes. Here, we establish the importance of the balance between these two factors for accurate regulation of the transition between the planktonic and sessile lifestyles. This balance is achieved by negative-feedback regulation of BolA and c-di-GMP. BolA not only contributes directly to the motility of bacteria but also regulates the expression of diguanylate cyclases and phosphodiesterases. This expression modulation influences the synthesis and degradation of c-di-GMP, while this signaling metabolite has a negative influence in bolA mRNA transcription. Finally, we present evidence of the dominant role of BolA in biofilm, showing that, even in the presence of elevated c-di-GMP levels, biofilm formation is reduced in the absence of BolA. C-di-GMP is one of the most important bacterial second messengers involved in several cellular processes, including virulence, cell cycle regulation, biofilm formation, and flagellar synthesis. In this study, we unravelled a direct connection between the bolA morphogene and the c-di-GMP signaling molecule. We show the important cross-talk that occurs between these two molecular regulators during the transition between the motile/planktonic and adhesive/sessile lifestyles in Escherichia coli This work provides important clues that can be helpful in the development of new strategies, and the results can be applied to other organisms with relevance for human health. IMPORTANCE Bacterial cells have evolved several

Extending the bidding format to promote demand response

International Nuclear Information System (INIS)

Liu, Yanchao; Holzer, Jesse T.; Ferris, Michael C.

2015-01-01

We propose an extended bidding structure to allow more realistic demand characteristics and behaviors to be expressed via flexible bids. In today's ISO-run energy markets, demand bid formats are all separable over time. However, a significant and growing segment of demand can be shifted across time and therefore has no way to bid its true valuation of consumption. We propose additional bid types that allow deferrable, adjustable and storage-type loads to better express their value, and thus elicit demand response in the most natural way – via direct participation in the market. We show that the additional bid types are easily incorporated into the existing market with no technological barrier and that they preserve the market's efficiency and incentive-compatibility properties. Using real market data, we give a numerical demonstration that the extended bid format could substantially increase social welfare, and also present additional insight on storage expansion scenarios. - Highlights: • Three new bid types are proposed to enrich demand-side participation. • Time value of electricity demand can be clearly conveyed to central dispatcher. • The extended format preserves market efficiency and incentive compatibility. • Energy storage is most effective to neutralize price volatility, with a limitation.

Variations in the formation of the human caudal spinal cord.

Science.gov (United States)

Saraga-Babić, M; Sapunar, D; Wartiovaara, J

1995-01-01

Collection of 15 human embryos between 4-8 developmental weeks was used to histologically investigate variations in the development of the caudal part of the spinal cord and the neighboring axial organs (notochord and vertebral column). In the 4-week embryo, two types of neurulation were parallelly observed along the anteroposterior body axis: primary in the areas cranial to the neuroporus caudalis and secondary in the more caudal tail regions. In the 5-week embryos, both parts of the neural tube fused, forming only one continuous lumen in the developing spinal cord. In the three examined embryos we found anomalous pattern of spinal cord formation. Caudal parts of these spinal cords displayed division of their central canal into two or three separate lumina, each surrounded by neuroepithelial layer. In the caudal area of the spinal cord, derived by secondary neurulation, formation of separate lumina was neither connected to any anomalous notochord or vertebral column formation, nor the appearance of any major axial disturbances. We suggest that development of the caudal part of the spinal cord differs from its cranial region not only in the type of neurulation, but also in the destiny of its derivatives and possible modes of abnormality formation.

Melanocortin Receptor Agonists Facilitate Oxytocin-Dependent Partner Preference Formation in the Prairie Vole.

Science.gov (United States)

Modi, Meera E; Inoue, Kiyoshi; Barrett, Catherine E; Kittelberger, Kara A; Smith, Daniel G; Landgraf, Rainer; Young, Larry J

2015-07-01

The central melanocortin (MC) system has been widely studied for its effects on food intake and sexual behavior. However, the MC system, and more specifically the MC4 receptor (MC4R), also interacts with neurochemical systems that regulate socioemotional behaviors, including oxytocin (OT) and dopamine. In monogamous prairie voles, OT and dopamine interact to promote partner preference formation, a laboratory measure of an enduring social bond between mates. Here we investigated the effects of MC receptor activation on partner preference formation in prairie voles, as well as the interaction between the MC and OT systems during this process. Peripheral administration of the brain penetrant MC3/4R receptor peptide agonist, Melanotan II (MTII), and the highly selective, small-molecule MC4R agonist, Pf-446687, enhanced partner preference formation in the prairie vole, but not in the non-monogamous meadow vole. MTII-induced partner preferences were enduring, as they were present 1 week after drug manipulation. The prosocial effects of MCR agonists may be mediated, in part, through modulation of OT, as coadministration of an OT receptor antagonist prevented MTII-induced partner preferences. MTII also selectively activated hypothalamic OT neurons and potentiated central OT release. As OT has been shown to enhance some aspects of social cognition in humans, our data suggest that the MC4R may be a viable therapeutic target for enhancing social function in psychiatric disorders, including autism spectrum disorders and schizophrenia, potentially through activation of the OT system.

Formation of diapiric structure in the deformation zone, central Indian Ocean: A model from gravity and seismic reflection data

Digital Repository Service at National Institute of Oceanography (India)

Krishna, K.S.; Rao, D.G.; Neprochnov, Y.P.

Analyses of bathymetry, gravity and seismic reflection data of the diffusive plate boundary in the central Indian Ocean reveal a new kind of deformed structure besides the well-reported structures of long-wavelength anticlinal basement rises...

Sandy lower Gotherivian reservoirs in the south central Turkmeniya. [Siberia

Energy Technology Data Exchange (ETDEWEB)

Mavyyev, N.Ch.; Nedirov, B.R.

1982-01-01

Composition and capacitance-filtering properties of sandy rocks of the early Gotherivian age developed on the fields of Karadzhaulak and Cirili within the northeast slope of the Predkopetdag marginal trough and on areas of Dengli Bakharadok of the Bakharadok monocline are studied. These rocks are viewed as analogs of the gas-bearing Shatlyk level of the Murgabskiy Basin. They can be considered the main potential source of hydrocarbons on the studied territory. In the upper part of the lower Gotherivian, a level of sandy rocks is traced. Rocks represented by small-and average-grained red and light grey differences in sandstones of polymictic composition. The porosity of the sandstones is 20-22%, permeability is 200-500 mdarcy. Not only a similar stratigraphic position of the described sandstones in the lower Gotherivian was found, but also lithological common nature of the rocks. In the south central Turkmeniya one can isolate age analogs of the Shatlyk level, the main productive level of southeast Turkmeniya. The thickness of the sandy beds is from 17 to 45 m. The sandstones of the Karadzhaulak area have the best capacitance-filtering properties. Post sedimentation changes depend on the quantity and composition of the cement, influence of formation waters, and possibly thermobaric conditions of rock formation. The presence of sandy rocks with high collector properties in the cross section of the lower Gotherivian deposits in south central Turkmeniya should be considered in determining the objects for further prospecting and exploration. The areas of Kumbet and Karadzhaulak are primary.

Geology and uranium occurrences in the Forez tertiary plain (in the French 'Massif Central'); Geologie et mineralisations uraniferes de la plaine tertiaire du Forez (Massif Central francais)

Energy Technology Data Exchange (ETDEWEB)

Duclos, P. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses - 92 (France). Centre d' Etudes Nucleaires

1967-01-01

In the first part, the observations made during the geological survey of the Forez Tertiary plain (in the French 'Massif Central') are recalled. Then, using various methods, the author lists the formations according to chronology. Finally, a reconstitution of the geological history of this subsidence basin is attempted. In the second part, the occurrence of 17 uranium bearing geochemical anomalies is commented upon. Each of these various anomalies is given a place on the stratigraphic scale. This enables the author to put the successive phases of uranium deposition into their proper perspective in the history of the plain. In conclusion, the author points out the usefulness of these uraniferous geochemical anomalies. (author) [French] Dans la premiere partie, l'auteur rappelle les observations faites au cours de l'etude geologique de la plaine tertiaire du Forez (Massif Central francais). Puis se servant de differentes methodes, il etablit une chronologie des formations. Enfin, il termine par un essai de reconstitution de l'histoire geologique de ce bassin de subsidence. Dans la deuxieme partie, il commente la decouverte de 17 anomalies geochimiques uraniferes. Il situe ces differentes anomalies dans la serie stratigraphique. Ceci lui permet de replacer les depots successifs de l'uranium dans l'histoire de la plaine. Enfin, il indique l'interet de ces anomalies geochimiques uraniferes. (auteur)

La fracturation et les bandes de déformation dans la région d’El Kohol (Atlas saharien central, Algérie: analyse fractale, lois d’échelles et modèle de réseaux de fractures discrètes

Directory of Open Access Journals (Sweden)

Zazoun, R. S.

2015-12-01

Full Text Available The aim of this paper is focused on the study of natural fractures and deformation bands in El Kohol structure, located in the Djebel Amour in the Central Saharan Atlas, Algeria. The field observations and measurements were performed through two localities on the forelimb and two others on the backlimb of the structure. The outcrop study has shown the existence of five fracture sets and three deformation bands sets. The spacing and length distribution models of the different fractures sets obey to a power law. The mechanical layer thickness analysis for the whole formations shows the existence of twelve mechanical units with a stratabound control. The deformation bands show an increasing in their numbers, and a decreasing in their spacing when they approach the major faults. The fractal analysis of faults and fractures, as well as the deformation bands show a fractal character of 2D dimension. A good correlation coefficients is obtained from the comparison between the density and the intensity parameters (Pxy calculated from the discrete fracture network (DFN modelling, and those from the outcrops. The model developed is discussed related to deformation events recognized in the area.[fr] Ce travail porte sur l’étude de la fracturation naturelle et les bandes de déformation dans la structure plicative d’El Kohol, du le Djebel Amour, dans l’Atlas saharien central. Les observations et les mesures ont été effectuées à travers deux stations sur le flanc court ou avant de la structure, et deux stations sur le flanc long ou arrière. L’étude a montré l’existence de cinq familles de fractures et de trois familles de bandes de déformation. Les modèles de distribution des espacements et des longueurs des différentes familles de fractures obéit à une loi de type puissance. L’analyse mécanostratigraphique montre une subdivision des formations étudiées en douze unités mécaniques. Les bandes de déformation montrent une

The Maximum Mass Solar Nebula and the early formation of planets

Science.gov (United States)

Nixon, C. J.; King, A. R.; Pringle, J. E.

2018-03-01

Current planet formation theories provide successful frameworks with which to interpret the array of new observational data in this field. However, each of the two main theories (core accretion, gravitational instability) is unable to explain some key aspects. In many planet formation calculations, it is usual to treat the initial properties of the planet forming disc (mass, radius, etc.) as free parameters. In this paper, we stress the importance of setting the formation of planet forming discs within the context of the formation of the central stars. By exploring the early stages of disc formation, we introduce the concept of the Maximum Mass Solar Nebula (MMSN), as opposed to the oft-used Minimum Mass Solar Nebula (here mmsn). It is evident that almost all protoplanetary discs start their evolution in a strongly self-gravitating state. In agreement with almost all previous work in this area, we conclude that on the scales relevant to planet formation these discs are not gravitationally unstable to gas fragmentation, but instead form strong, transient spiral arms. These spiral arms can act as efficient dust traps allowing the accumulation and subsequent fragmentation of the dust (but not the gas). This phase is likely to populate the disc with relatively large planetesimals on short timescales while the disc is still veiled by a dusty-gas envelope. Crucially, the early formation of large planetesimals overcomes the main barriers remaining within the core accretion model. A prediction of this picture is that essentially all observable protoplanetary discs are already planet hosting.

STAR Formation Histories Across the Interacting Galaxy NGC 6872, the Largest-Known Spiral

Science.gov (United States)

Eufrasio, Rafael T.; Dwek, E.; Arendt, RIchard G.; deMello, Duilia F.; Gadotti, DImitri A.; Urrutia-Viscarra, Fernanda; deOliveira, CLaudia Mendes; Benford, Dominic J.

2014-01-01

NGC6872, hereafter the Condor, is a large spiral galaxy that is interacting with its closest companion, the S0 galaxy IC 4970. The extent of the Condor provides an opportunity for detailed investigation of the impact of the interaction on the current star formation rate and its history across the galaxy, on the age and spatial distribution of its stellar population, and on the mechanism that drives the star formation activity. To address these issues we analyzed the far-ultraviolet (FUV) to near-infrared (near-IR) spectral energy distribution of seventeen 10 kpc diameter regions across the galaxy, and derived their star formation history, current star formation rate, and stellar population and mass. We find that most of the star formation takes place in the extended arms, with very little star formation in the central 5 kpc of the galaxy, in contrast to what was predicted from previous numerical simulations. There is a trend of increasing star formation activity with distance from the nucleus of the galaxy, and no evidence for a recent increase in the current star formation rate due to the interaction. The nucleus itself shows no significant current star formation activity. The extent of the Condor also provides an opportunity to test the applicability of a single standard prescription for conversion of the FUV + IR (22 micrometer) intensities to a star formation rate for all regions. We find that the conversion factor differs from region to region, arising from regional differences in the stellar populations.

Current denudation rates in dolostone karst from central Spain: Implications for the formation of unroofed caves

Science.gov (United States)

Krklec, Kristina; Domínguez-Villar, David; Carrasco, Rosa M.; Pedraza, Javier

2016-07-01

Rock tablets of known weight were buried in the soil of a karst region in Central Spain to evaluate the carbonate weathering during a period of a year. The experiment was conducted at two different soil depths: 5-10 and 50-55 cm from the surface. The parental rock used in the experiment is composed of dolomite and magnesite with variable proportion of accessory minerals and minor elements. Soil mineral and chemical composition as well as its texture was also characterized. Meteorological conditions at the site together with temperature and CO2 in both soil levels were monitored. Sets of tablets were retrieved after 6 and 12 months of the start of the experiment to account for seasonal weathering. Different lithologies do not exhibit significant differences in weathering, although a large inter-sample variability is attributed to variable size and distribution of the porosity. Results show an enhanced weathering during the wet and cold season that accounts for 78 ± 1% of the total annual weathering. Rock tablets examined under scanning electron microscopy prior and after exposure to natural environment show that most of the material lost occurred along cracks, edges or large pores. Although dissolution is a common process, most of the weathering is due to crystal detachment. Rock tablets at the depth of 5-10 cm were weathered 68 ± 1% more than those set at 50-55 cm from the surface. Higher soil moisture and concentration of CO2 were found deeper in the soil, which likely enhanced the dissolution of carbonate. However, physical weathering dominated weight loss of rock tablets at both soil depths; especially at the 5-10 cm level where soil thermal and moisture cycles were more frequent and greater. Denudation rate calculated from the 12 months set provides values of 2.48 ± 1.07 μm/yr and 1.75 ± 0.66 μm/yr at the depths of 5-10 and 50-55 cm, respectively. Since the conditions at the average contact between soil and bedrock are similar to those at the 50-55 cm

Neural and Cellular Mechanisms of Fear and Extinction Memory Formation

Science.gov (United States)

Orsini, Caitlin A.; Maren, Stephen

2012-01-01

Over the course of natural history, countless animal species have evolved adaptive behavioral systems to cope with dangerous situations and promote survival. Emotional memories are central to these defense systems because they are rapidly acquired and prepare organisms for future threat. Unfortunately, the persistence and intrusion of memories of fearful experiences are quite common and can lead to pathogenic conditions, such as anxiety and phobias. Over the course of the last thirty years, neuroscientists and psychologists alike have attempted to understand the mechanisms by which the brain encodes and maintains these aversive memories. Of equal interest, though, is the neurobiology of extinction memory formation as this may shape current therapeutic techniques. Here we review the extant literature on the neurobiology of fear and extinction memory formation, with a strong focus on the cellular and molecular mechanisms underlying these processes. PMID:22230704

Is banking supervision central to central banking?

OpenAIRE

Joe Peek; Eric S. Rosengren; Geoffrey M. B. Tootell

1997-01-01

Whether central banks should play an active role in bank supervision and regulation is being debated both in the United States and abroad. While the Bank of England has recently been stripped of its supervisory responsibilities and several proposals in the United States have advocated removing bank supervision from the Federal Reserve System, other countries are considering enhancing central bank involvement in this area. Many of the arguments for and against these proposals hinge on the effe...

Murgabskaya Oblast, a promising gas region of Central Asia

Energy Technology Data Exchange (ETDEWEB)

Amanniyazov, K.N.; Abdyyev, A.A.

1981-01-01

Gas fields of the Murgabskiy region are multiple-bed. The industrial gas content is associated with the sandy-terrigenous formations of the Shatlyk productive level of the lower Goterivskiy stage. The gas formation is anticlinal, occasionally floating. A map is compiled for the dispersal of the Shatlyk level which isolates the lithological composition, thickness, zones of dispersal of sandstone, etc. A description is provided for the map plan of the Shatlyk level. Alternation of sandy-argillaceous and carbonate rocks created favorable prerequisites for the development in the deposits of the Neocomian of lithological-physical pairs of ''collectors-mantles'', the basis for trap formation in structures and zones of lithological substitution. Within the Murgabskiy region, the greatest outlook for discovering new gas fields is confined to the Shatlyk level. It is associated with the central part of the Murgabskiy Basin where major deposits have already been discovered. A group of structures in the eastern submersion of the Kopetdag trough at the junction of the Murgabskiy Basin is important. The structures at the junction of East Kopetdag and the Murgabskiy Basin may be promising. The outlook for possible gas is associated with deposits of the lower cretaceous and Sharaplinksiy level. The main task must be comprehensive in investigation of the suprasaline apt-Neocomian and Kimmeridgian-Tithonian deposits as possible multiple-bed gas and oil containing masses.

[Formation of medical education in North Korea: 1945-1948].

Science.gov (United States)

Heo, Yun-Jung; Cho, Young-Soo

2014-08-01

This study focuses on the formation of medical education in North Korea from 1945 to 1948 in terms of the centralization of medical education, and on the process and significance of the systemization of medical education. Doctors of the past trained under the Japanese colonial system lived and worked as liberalists. More than half of these doctors who were in North Korea defected to South Korea after the country was liberated. Thus the North Korean regime faced the urgent task of cultivating new doctors who would 'serve the state and people.' Since the autumn of 1945, right after national liberation, Local People's Committees organized and implemented medical education autonomously. Following the establishment of the Provisional People's Committee of North Korea, democratic reform was launched, leading to the centralized administration of education. Consequently, medical educational institutions were realigned, with some elevated to medical colleges and others shut down. The North Korean state criticised the liberalistic attitude of doctors and the bureaucratic style of health administration, and tried to reform their political consciousness through political inculcation programs. The state also grant doctors living and housing privileges, which show its endeavor to build 'state medicine'. By 1947, a medical education system was established in which the education administration was put in charge of training new doctors while the health administration was put in charge of nurturing and retraining health workers. In this way, the state was the principal agent that actively established a centralized administrative system in the process of the formation of medical education in North Korea following national liberation. Another agent was deeply involved in this process - the faculty that was directly in charge of educating the new doctors. Studying the medical faculty remains another research task for the future. By exploring how the knowledge, generational experience

Central Nervous Insulin Signaling in Sleep-Associated Memory Formation and Neuroendocrine Regulation.

Science.gov (United States)

Feld, Gordon B; Wilhem, Ines; Benedict, Christian; Rüdel, Benjamin; Klameth, Corinna; Born, Jan; Hallschmid, Manfred

2016-05-01

The neurochemical underpinnings of sleep's contribution to the establishment and maintenance of memory traces are largely unexplored. Considering that intranasal insulin administration to the CNS improves memory functions in healthy and memory-impaired humans, we tested whether brain insulin signaling and sleep interact to enhance memory consolidation in healthy participants. We investigated the effect of intranasal insulin on sleep-associated neurophysiological and neuroendocrine parameters and memory consolidation in 16 men and 16 women (aged 18-30 years), who learned a declarative word-pair task and a procedural finger sequence tapping task in the evening before intranasal insulin (160 IU) or placebo administration and 8 h of nocturnal sleep. On the subsequent evening, they learned interfering word-pairs and a new finger sequence before retrieving the original memories. Insulin increased growth hormone concentrations in the first night-half and EEG delta power during the second 90 min of non-rapid-eye-movement sleep. Insulin treatment impaired the acquisition of new contents in both the declarative and procedural memory systems on the next day, whereas retrieval of original memories was unchanged. Results indicate that sleep-associated memory consolidation is not a primary mediator of insulin's acute memory-improving effect, but that the peptide acts on mechanisms that diminish the subsequent encoding of novel information. Thus, by inhibiting processes of active forgetting during sleep, central nervous insulin might reduce the interfering influence of encoding new information.

Approximations to galaxy star formation rate histories: properties and uses of two examples

Science.gov (United States)

Cohn, J. D.

2018-05-01

Galaxies evolve via a complex interaction of numerous different physical processes, scales and components. In spite of this, overall trends often appear. Simplified models for galaxy histories can be used to search for and capture such emergent trends, and thus to interpret and compare results of galaxy formation models to each other and to nature. Here, two approximations are applied to galaxy integrated star formation rate histories, drawn from a semi-analytic model grafted onto a dark matter simulation. Both a lognormal functional form and principal component analysis (PCA) approximate the integrated star formation rate histories fairly well. Machine learning, based upon simplified galaxy halo histories, is somewhat successful at recovering both fits. The fits to the histories give fixed time star formation rates which have notable scatter from their true final time rates, especially for quiescent and "green valley" galaxies, and more so for the PCA fit. For classifying galaxies into subfamilies sharing similar integrated histories, both approximations are better than using final stellar mass or specific star formation rate. Several subsamples from the simulation illustrate how these simple parameterizations provide points of contact for comparisons between different galaxy formation samples, or more generally, models. As a side result, the halo masses of simulated galaxies with early peak star formation rate (according to the lognormal fit) are bimodal. The galaxies with a lower halo mass at peak star formation rate appear to stall in their halo growth, even though they are central in their host halos.

ScienceCentral: open access full-text archive of scientific journals based on Journal Article Tag Suite regardless of their languages.

Science.gov (United States)

Huh, Sun

2013-01-01

ScienceCentral, a free or open access, full-text archive of scientific journal literature at the Korean Federation of Science and Technology Societies, was under test in September 2013. Since it is a Journal Article Tag Suite-based full text database, extensible markup language files of all languages can be presented, according to Unicode Transformation Format 8-bit encoding. It is comparable to PubMed Central: however, there are two distinct differences. First, its scope comprises all science fields; second, it accepts all language journals. Launching ScienceCentral is the first step for free access or open access academic scientific journals of all languages to leap to the world, including scientific journals from Croatia.

Formate Formation and Formate Conversion in Biological Fuels Production

Directory of Open Access Journals (Sweden)

Bryan R. Crable

2011-01-01

Full Text Available Biomethanation is a mature technology for fuel production. Fourth generation biofuels research will focus on sequestering CO2 and providing carbon-neutral or carbon-negative strategies to cope with dwindling fossil fuel supplies and environmental impact. Formate is an important intermediate in the methanogenic breakdown of complex organic material and serves as an important precursor for biological fuels production in the form of methane, hydrogen, and potentially methanol. Formate is produced by either CoA-dependent cleavage of pyruvate or enzymatic reduction of CO2 in an NADH- or ferredoxin-dependent manner. Formate is consumed through oxidation to CO2 and H2 or can be further reduced via the Wood-Ljungdahl pathway for carbon fixation or industrially for the production of methanol. Here, we review the enzymes involved in the interconversion of formate and discuss potential applications for biofuels production.

MAGNETIC FLUX EXPULSION IN STAR FORMATION

International Nuclear Information System (INIS)

Zhao Bo; Li Zhiyun; Nakamura, Fumitaka; Krasnopolsky, Ruben; Shang, Hsien

2011-01-01

Stars form in dense cores of magnetized molecular clouds. If the magnetic flux threading the cores is dragged into the stars, the stellar field would be orders of magnitude stronger than observed. This well-known 'magnetic flux problem' demands that most of the core magnetic flux be decoupled from the matter that enters the star. We carry out the first exploration of what happens to the decoupled magnetic flux in three dimensions, using a magnetohydrodynamic (MHD) version of the ENZO adaptive mesh refinement code. The field-matter decoupling is achieved through a sink particle treatment, which is needed to follow the protostellar accretion phase of star formation. We find that the accumulation of the decoupled flux near the accreting protostar leads to a magnetic pressure buildup. The high pressure is released anisotropically along the path of least resistance. It drives a low-density expanding region in which the decoupled magnetic flux is expelled. This decoupling-enabled magnetic structure has never been seen before in three-dimensional MHD simulations of star formation. It generates a strong asymmetry in the protostellar accretion flow, potentially giving a kick to the star. In the presence of an initial core rotation, the structure presents an obstacle to the formation of a rotationally supported disk, in addition to magnetic braking, by acting as a rigid magnetic wall that prevents the rotating gas from completing a full orbit around the central object. We conclude that the decoupled magnetic flux from the stellar matter can strongly affect the protostellar collapse dynamics.

Brain-derived neurotrophic factor mediates estradiol-induced dendritic spine formation in hippocampal neurons

Science.gov (United States)

Murphy, Diane D.; Cole, Nelson B.; Segal, Menahem

1998-01-01

Dendritic spines are of major importance in information processing and memory formation in central neurons. Estradiol has been shown to induce an increase of dendritic spine density on hippocampal neurons in vivo and in vitro. The neurotrophin brain-derived neurotrophic factor (BDNF) recently has been implicated in neuronal maturation, plasticity, and regulation of GABAergic interneurons. We now demonstrate that estradiol down-regulates BDNF in cultured hippocampal neurons to 40% of control values within 24 hr of exposure. This, in turn, decreases inhibition and increases excitatory tone in pyramidal neurons, leading to a 2-fold increase in dendritic spine density. Exogenous BDNF blocks the effects of estradiol on spine formation, and BDNF depletion with a selective antisense oligonucleotide mimics the effects of estradiol. Addition of BDNF antibodies also increases spine density, and diazepam, which facilitates GABAergic neurotransmission, blocks estradiol-induced spine formation. These observations demonstrate a functional link between estradiol, BDNF as a potent regulator of GABAergic interneurons, and activity-dependent formation of dendritic spines in hippocampal neurons. PMID:9736750

The Katmandu and Gosainkund nappes, central Nepal Himalaya (cartography, structure, metamorphism, geochemistry and radio-chronology)

International Nuclear Information System (INIS)

Rai, S.M.

1998-10-01

In central Nepal, a multidisciplinary study has been carried out to characterize and distinguish the crystalline nappes of Katmandu and Gosainkund from the Midland formations. Two principal deformations are recorded: one ductile, syn-metamorphic, marked by microstructures (stretching lineation, S-C structures, etc. ), another, post-metamorphic, recorded by an anticline, roughly EW -directed, and by NNE-SSW -directed folds. The syn-metamorphic P-T conditions show differences between Katmandu Crystalline Nappe (900-720 MPa; 700-480 deg C) and Gosainkund Crystalline Nappe (890-580 MPa; 750-590 deg C). They exhibit well preserved inverted metamorphism between the Upper Midland Formations (750 Mpa; 560 deg C) and the Gosainkund Nappe. In central Nepal, the augen gneisses and the 'Lesser Himalayan' Cambro-Ordovician granites bear similar petrographic and geochemical characteristics which suggest a common origin. However, the geological setting and age of the Proterozoic Ulleri augen gneiss rule out correlation with these formations. 40 Ar/ 39 Ar analyses of muscovite, indicate cooling ages younger from south to north: 22 to 13 Ma in the Katmandu Nappe, 16 to 5 Ma in the Gosainkund Nappe, and 12 to 6 Ma in the Midland Formation. The principal points summarized by this study are the following: clear distinction between two nappes marked by their litho-stratigraphy and metamorphism; the ductile movement of MCT in the north of Katmandu is blocked since approximately 25 Ma; the late emplacement and late or common post metamorphic history of the two nappes; but earlier cooling history of the Katmandu nappe; the present uplift of the Katmandu region, underlined by the intense micro-seismicity, concerns indifferently the two nappes that form a single tectonic block at present; the combined uplift of the two nappes is due to the displacement on a ramp of major decollement surface. (author)

Lower Cretaceous Luscar group (revised) of the northern and north-central foothills of Alberta

Energy Technology Data Exchange (ETDEWEB)

Langenberg, C W; McMechan, M E

1985-03-01

Lower Cretaceous coal-bearing strata exposed in the northern and north-central foothills of Alberta form part of a predominantly nonmarine succession that extends from Montana to northeastern British Columbia. The Luscar Group (revised) forms the sequence of coal bearing Lower Cretaceous strata that disconformably overlies marine and nonmarine strata of the Nikanassin Formation or Minnes Group and disconformably underlies marine shales of the Blackstone or Shaftesbury formations. It includes a thin, basal conglomerate, a predominantly nonmarine sandstone and shale unit that locally contains coal; a marine shale and sandstone unit, and an upper nonmarine sandstone and shale unit that contains thick commercial coal seams. These units form the Cadomin, Gladstone, Moosebar and Gates formations, respectively. The Luscar Group is exposed from Kakwa River to Clearwater River in the Foothills of Alberta. It represents a slight modification, by the inclusion of the thin basal conglomerate, from the previous usage of the term Luscar in the northern Foothills of Alberta. 25 references.

Reconnaissance Rb-Sr dates for the Himalayan Central Gneiss, Northwest India

International Nuclear Information System (INIS)

Powell, C. McA.; Crawford, A.R.; Armstrong, R.L.; Wynne-Edwards, H.R.; Prakash, R.

1979-01-01

Rb-Sr analysis of whole-rock samples and biotite and biotite - or muscovite - whole rock pairs suggests that the Himalayan Central Gneiss in the crystalline nappes of the Lesser Himalaya and the root zone in the High Himalaya was formed during Oligocene to mid-Miocene times by deformation and metamorphism of older rocks, including Precambrian. Four whole-rock samples from the Almora-Askot thrust sheets define an isochron of 1620 +- 90 Ma with a high initial 87 Sr/ 86 Sr ratio of 0.749 +- 0.007; other single whole-rock samples give dates in the range 268 to 1065 Ma, assuming an initial 87 Sr/ 86 Sr ratio of 0.704. These dates are considered to represent either depositional or early instructive/deformational events. Three biotite-whole rock pairs from the root zone of the Himalayan Central Gneiss in Lahaul give aqes of 16 to 19 Ma and two muscovite-whole rock pairs give similar mid-Cenozoic ages (12 and 26 Ma); two muscovite-whole rock pairs give Paleozoic ages, which suggests incomplete resetting of the muscovite by the Cenozoic metamorphism. The pattern of ages is similar to recent results from adjacent areas, and consistent with models of Himalayan tectonics involving formation of the Central Gneiss from older Indian crust during the mid-Cenozoic. (auth.)

Central region component1, a novel synaptonemal complex component, is essential for meiotic recombination initiation in rice.

Science.gov (United States)

Miao, Chunbo; Tang, Ding; Zhang, Honggen; Wang, Mo; Li, Yafei; Tang, Shuzhu; Yu, Hengxiu; Gu, Minghong; Cheng, Zhukuan

2013-08-01

In meiosis, homologous recombination entails programmed DNA double-strand break (DSB) formation and synaptonemal complex (SC) assembly coupled with the DSB repair. Although SCs display extensive structural conservation among species, their components identified are poorly conserved at the sequence level. Here, we identified a novel SC component, designated central region component1 (CRC1), in rice (Oryza sativa). CRC1 colocalizes with ZEP1, the rice SC transverse filament protein, to the central region of SCs in a mutually dependent fashion. Consistent with this colocalization, CRC1 interacts with ZEP1 in yeast two-hybrid assays. CRC1 is orthologous to Saccharomyces cerevisiae pachytene checkpoint2 (Pch2) and Mus musculus THYROID receptor-interacting protein13 (TRIP13) and may be a conserved SC component. Additionally, we provide evidence that CRC1 is essential for meiotic DSB formation. CRC1 interacts with homologous pairing aberration in rice meiosis1 (PAIR1) in vitro, suggesting that these proteins act as a complex to promote DSB formation. PAIR2, the rice ortholog of budding yeast homolog pairing1, is required for homologous chromosome pairing. We found that CRC1 is also essential for the recruitment of PAIR2 onto meiotic chromosomes. The roles of CRC1 identified here have not been reported for Pch2 or TRIP13.

ALICE measurements in p–Pb collisions: Charged particle multiplicity, centrality determination and implications for binary scaling

Energy Technology Data Exchange (ETDEWEB)

Toia, Alberica, E-mail: alberica.toia@cern.ch [Istituto Nazionale di Fisica Nucleare, Padova (Italy); Goethe University Frankfurt (Germany)

2014-06-15

Measurements of particle production in proton–nucleus collisions provide a reference to disentangle final state effects, i.e. signatures of the formation of a deconfined hot medium, from initial state effects, already present in cold nuclear matter. Since many initial state effects are expected to vary as function of the number of collisions suffered by the incoming proton, it is crucial to estimate the centrality of the collision. In p-Pb collisions categorization of events into different centrality classes using a particle multiplicity distribution is complicated by the low particle multiplicities and the large multiplicity fluctuations. We present ALICE measurements of particle production in p-Pb collisions at √(s{sub NN})=5.02 TeV, including the pseudo-rapidity and transverse momentum dependence, and we discuss the event classification in centrality classes and its implications for the measurements of nuclear modification factors.

Maxillary canine impactions related to impacted central incisors: two case reports.

Science.gov (United States)

Bayram, Mehmet; Ozer, Mete; Sener, Ismail

2007-09-01

The purpose of this case report is to describe the combined surgical and orthodontic treatment of two cases with an impacted maxillary central incisor and canine in the same quadrant and to discuss the causal relationship between them. The most common causes of canine impactions are usually the result of one or more factors such as a long path of eruption, tooth size-arch length discrepancies, abnormal position of the tooth bud, prolonged retention or early loss of the deciduous canine, trauma, the presence of an alveolar cleft, ankylosis, cystic or neoplastic formation, dilaceration of the root, supernumerary teeth, and odontomas. Although impaction of the maxillary central incisor is almost as prevalent as impacted canines its etiology is different. The principal factors involved in causing the anomaly are supernumerary teeth, odontomas, and trauma. Case #1: A 10.5-year-old girl in the early mixed dentition stage presented with a chief complaint of the appearance of her anterior teeth. She had a Class I skeletal pattern and a history of trauma to the maxillary central incisors at age five with premature exfoliation. Radiographs revealed an impacted upper right central incisor in the region of the nasal floor, delayed eruption of the maxillary permanent central incisor, and the adjacent lateral incisor was inclined toward the edentulous space. Treatment was done in two stages consisting of surgical exposure and traction of the impacted central incisor and fixed orthodontic treatment. Case #2: An 11.5-year-old girl presented for orthodontic treatment with the chief complaint of an unerupted tooth and the appearance of her upper anterior teeth. She was in the late mixed dentition period with a Class III skeletal pattern along with an anterior cross-bite with some maxillary transverse deficiency. The maxillary right canine and central incisor were absent, but the maxillary right deciduous canine was still present. Treatment included arch expansion followed by

Neural Correlates of Auditory Processing, Learning and Memory Formation in Songbirds

Science.gov (United States)

Pinaud, R.; Terleph, T. A.; Wynne, R. D.; Tremere, L. A.

Songbirds have emerged as powerful experimental models for the study of auditory processing of complex natural communication signals. Intact hearing is necessary for several behaviors in developing and adult animals including vocal learning, territorial defense, mate selection and individual recognition. These behaviors are thought to require the processing, discrimination and memorization of songs. Although much is known about the brain circuits that participate in sensorimotor (auditory-vocal) integration, especially the ``song-control" system, less is known about the anatomical and functional organization of central auditory pathways. Here we discuss findings associated with a telencephalic auditory area known as the caudomedial nidopallium (NCM). NCM has attracted significant interest as it exhibits functional properties that may support higher order auditory functions such as stimulus discrimination and the formation of auditory memories. NCM neurons are vigorously dr iven by auditory stimuli. Interestingly, these responses are selective to conspecific, relative to heterospecific songs and artificial stimuli. In addition, forms of experience-dependent plasticity occur in NCM and are song-specific. Finally, recent experiments employing high-throughput quantitative proteomics suggest that complex protein regulatory pathways are engaged in NCM as a result of auditory experience. These molecular cascades are likely central to experience-associated plasticity of NCM circuitry and may be part of a network of calcium-driven molecular events that support the formation of auditory memory traces.

Constraints on superoxide mediated formation of manganese oxides

Directory of Open Access Journals (Sweden)

Deric R. Learman

2013-09-01

Full Text Available Manganese (Mn oxides are among the most reactive sorbents and oxidants within the environment, where they play a central role in the cycling of nutrients, metals, and carbon. Recent discoveries have identified superoxide (O2- (both of biogenic and abiogenic origin as an effective oxidant of Mn(II leading to the formation of Mn oxides. Here we examined the conditions under which abiotically produced superoxide led to oxidative precipitation of Mn and the solid-phases produced. Oxidized Mn, as both aqueous Mn(III and Mn(III/IV oxides, was only observed in the presence of active catalase, indicating that hydrogen peroxide, a product of the reaction of O2- with Mn(II, inhibits the oxidation process presumably through the reduction of Mn(III. Citrate and pyrophosphate increased the yield of oxidized Mn but decreased the amount of Mn oxide produced via formation of Mn(III-ligand complexes. While complexing ligands played a role in stabilizing Mn(III, they did not eliminate the inhibition of net Mn(III formation by H2O2. The Mn oxides precipitated were highly disordered colloidal hexagonal birnessite, similar to those produced by biotically generated superoxide. Yet, in contrast to the large particulate Mn oxides formed by biogenic superoxide, abiotic Mn oxides did not ripen to larger, more crystalline phases. This suggests that the deposition of crystalline Mn oxides within the environment requires a biological, or at least organic, influence. This work provides the first direct evidence that, under conditions relevant to natural waters, oxidation of Mn(II by superoxide can occur and lead to formation of Mn oxides. For organisms that oxidize Mn(II by producing superoxide, these findings may also point to other microbially mediated processes, in particular enzymatic hydrogen peroxide degradation and/or production of organic ligand metabolites, that allow for Mn oxide formation.

The Star Formation History in the M31 Bulge

Science.gov (United States)

Dong, Hui; Olsen, Knut; Lauer, Tod; Saha, Abhijit; Li, Zhiyuan; García-Benito, Ruben; Schödel, Rainer

2018-05-01

We present the study of stellar populations in the central 5.5' (˜1.2 kpc) of the M31 bulge by using the optical color magnitude diagram derived from HST ACS WFC/HRC observations. In order to enhance image quality and then obtain deeper photometry, we construct Nyquist-sampled images and use a deconvolution method to detect sources and measure their photometry. We demonstrate that our method performs better than DOLPHOT in the extremely crowded region. The resolved stars in the M31 bulge have been divided into nine annuli and the color magnitude diagram fitting is performed for each of them. We confirm that the majority of stars (>70%) in the M31 bulge are indeed very old (> 5 Gyr) and metal-rich ([Fe/H]˜0.3). At later times, the star formation rate decreased and then experienced a significant rise around 1 Gyr ago, which pervaded the entire M31 bulge. After that, stars formed at less than 500 Myr ago in the central 130" . Through simulation, we find that these intermediate-age stars cannot be the artifacts introduced by the blending effect. Our results suggest that although the majority of the M31 bulge are very old, the secular evolutionary process still continuously builds up the M31 bulge slowly. We compare our star formation history with an older analysis derived from the spectral energy distribution fitting, which suggests that the latter one is still a reasonable tool for the study of stellar populations in remote galaxies.

First hominoid from the Late Miocene of the Irrawaddy Formation (Myanmar.

Directory of Open Access Journals (Sweden)

Jean-Jacques Jaeger

2011-04-01

Full Text Available For over a century, a Neogene fossil mammal fauna has been known in the Irrawaddy Formation in central Myanmar. Unfortunately, the lack of accurately located fossiliferous sites and the absence of hominoid fossils have impeded paleontological studies. Here we describe the first hominoid found in Myanmar together with a Hipparion (s.l. associated mammal fauna from Irrawaddy Formation deposits dated between 10.4 and 8.8 Ma by biochronology and magnetostratigraphy. This hominoid documents a new species of Khoratpithecus, increasing thereby the Miocene diversity of southern Asian hominoids. The composition of the associated fauna as well as stable isotope data on Hipparion (s.l. indicate that it inhabited an evergreen forest in a C3-plant environment. Our results enlighten that late Miocene hominoids were more regionally diversified than other large mammals, pointing towards regionally-bounded evolution of the representatives of this group in Southeast Asia. The Irrawaddy Formation, with its extensive outcrops and long temporal range, has a great potential for improving our knowledge of hominoid evolution in Asia.

CRED Simrad em300 multibeam backscatter data of Howland Island, Pacific Remote Island Areas, Central Pacific in GeoTIFF format

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Multibeam backscatter imagery extracted from gridded bathymetry of the shelf and slope environments of Howland Atoll, Pacific Island Areas, Central Pacific. These...

CRED Simrad em300 multibeam backscatter data of Johnston Atoll, Pacific Remote Island Areas, Central Pacific in GeoTIFF format

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Multibeam backscatter imagery extracted from gridded bathymetry of the shelf and slope environments of Johnston Island, Pacific Island Areas, Central Pacific. These...

Pliocene-Pleistocene (Nukumaruan) lithostratigraphy of the Tangoio block, and origin of sedimentary cyclicity, central Hawke's Bay, new Zealand

International Nuclear Information System (INIS)

Haywick, D.W.; Lowe, D.A.; Beu, A.G.; Henderson, R.A.; Carter, R.M.

1991-01-01

Eleven formations are defined within the Pliocene-Pleistocene Petane Group in a 450 km 2 uplifted area of central Hawkes Bay (Tangoio block). In ascending order these are: Waipunga Formation (new), Esk Formation, Tutira Formation (new), Aropaoanui Formation (new), Darkys Spur Formation (new), Mairau Formation (new), Tangoio Formation, Te Ngaru Formation, Waipatiki Formation, Devils Elbow Formation, and Kaiwaka Formation. Petane Group strata are cyclothemic and alternate between coarse-grained lithofacies (greywacke gravel, siliciclastic and carbonate sand/sandstone and bioclastic limestone) ascribed to nonmarine and inner shelf depositional environments, and sandy/muddy-silt ('papa') ascribed to mid-shelf deposition. The Petane Group is characterised by remarkable lateral continuity of formations, contrasting with conspicuous vertical changes. This stratigraphic style is consistent with glacio-eustatic sea-level fluctuations as proposed by Vella and Beu and Edwards, whereby coarse-grained lithofacies were deposited during sea-level low stands and fine-grained lithofacies were deposited during sea-level high stands. Foraminifera extracted from low-stand lithofacies display opposite δ 18 O signatures to that predicted for glacio-eustasy, a result of synsedimentary seawater dilution during sea-level low stands, and/or isotopic exchange during meteoric diagenesis. Stratigraphic and sedimentary criteria indicate that the Petane Group was deposited under unique circumstances of rapid basinal subsidence and a high rate of sedimentation. This offers an explanation for the general rarity of cyclothemic successions in the Pliocene-Pleistocene stratigraphic record. (author). 45 refs., 9 figs., 1 tab

Dynamics and Formation of Obscuring Tori in AGNs

Energy Technology Data Exchange (ETDEWEB)

Bannikova, Elena Yu.; Sergeyev, Alexey V., E-mail: bannikova@astron.kharkov.ua [Institute of Radio Astronomy, National Academy of Science of Ukraine, Kharkiv (Ukraine); Institute of Astronomy, V. N. Karazin Kharkiv National University, Kharkiv (Ukraine)

2017-12-12

We considered the evolution of a self-gravitating clumpy torus in the gravitational field of the central mass of an active galactic nucleus (AGN) in the framework of the N-body problem. The initial conditions take into account winds with different opening angles. Results of our N-body simulations show that the clouds moving on orbits with a spread in inclinations and eccentricities form a toroidal region. The velocity of the clouds at the inner boundary of the torus is lower than in a disk model that can explain the observed rotation curves. We discuss the scenario of torus formation related with the beginning of the AGN stage.

The Staffing of Central Electricity Generating Board Nuclear Power Stations; Organigramme des centrales nucleaires du central electricity generating board; Politika v oblasti kadrov na atomnykh ehlektrostantsiyakh CEGB; El personal de las plantas nucleoelectricas de la central electricity generating board.

Energy Technology Data Exchange (ETDEWEB)

Bartlett, J. S.; Shepherd, G. T. [Central Electricity Generating Board, Western Division, Bristol (United Kingdom)

1963-10-15

An account is given of the staffing requirements and organization at a CEBG nuclear power station. The training of staff and licensing requirements for reactoroperating staff are discussed. Experience gained to data of the outcome of pre-operating training and detailed planning in the operational sphere is given. (author) [French] Le memoire donne un apercu de l'organigramme d'une centrale nucleaire du CEGB et des conditions auxquelles doit satisfaire le personnel (formation, qualifications requises pour la fonction d'operateur). Il rend compte egalement de l'experience acquise a ce jour quant a l'interet qu'il y a a former le personnel au prealable et a etablir des plans d'operation detailles. (author) [Spanish] La memoria informa sobre la organizacion de las centrales nucleoelectricas de la CEGB y sobre la plantilla de personal que estas requieren. Discute la formacion del personal y los requisitos para obtener la licencia de operador de reactores. Describe la experiencia adquirida hasta el presente en materia de formacion previa del personal y de organizacion detallada de las operaciones. (author) [Russian] Daetsya otchet o trebovaniyakh, pred{sup y}avlyaemykh k personalu, i organizatsiya nabora personala na atomnykh ehlektrostantsiyakh Tsentral'nogo upravleniya proizvodstva ehlektroehnergii (CEGB). Obsuzhdayutsya voprosy podgotovki personala i normativnykh trebovanij, pred{sup y}avlyaemykh k ehkspluatatsionnomu personalu. Izlagaetsya opyt, nakoplennyj k nastoyashchemu vremeni v rezul'tate osushchestvleniya predehkspluatatsionnoj podgotovki i podrobnogo planirovaniya v usloviyakh ehkspluatatsii. (author)

Predictions from star formation in the multiverse

International Nuclear Information System (INIS)

Bousso, Raphael; Leichenauer, Stefan

2010-01-01

We compute trivariate probability distributions in the landscape, scanning simultaneously over the cosmological constant, the primordial density contrast, and spatial curvature. We consider two different measures for regulating the divergences of eternal inflation, and three different models for observers. In one model, observers are assumed to arise in proportion to the entropy produced by stars; in the others, they arise at a fixed time (5 or 10x10 9 years) after star formation. The star formation rate, which underlies all our observer models, depends sensitively on the three scanning parameters. We employ a recently developed model of star formation in the multiverse, a considerable refinement over previous treatments of the astrophysical and cosmological properties of different pocket universes. For each combination of observer model and measure, we display all single and bivariate probability distributions, both with the remaining parameter(s) held fixed and marginalized. Our results depend only weakly on the observer model but more strongly on the measure. Using the causal diamond measure, the observed parameter values (or bounds) lie within the central 2σ of nearly all probability distributions we compute, and always within 3σ. This success is encouraging and rather nontrivial, considering the large size and dimension of the parameter space. The causal patch measure gives similar results as long as curvature is negligible. If curvature dominates, the causal patch leads to a novel runaway: it prefers a negative value of the cosmological constant, with the smallest magnitude available in the landscape.

Central Nervous System Vasculitis

Science.gov (United States)

... of Vasculitis / Central Nervous System (CNS) Vasculitis Central Nervous System (CNS) Vasculitis Swap out your current Facebook Profile ... Facebook personal page. Replace with this image. Central nervous system (CNS) vasculitis is inflammation of blood vessel walls ...

STAR FORMATION AT VERY LOW METALLICITY. V. THE GREATER IMPORTANCE OF INITIAL CONDITIONS COMPARED TO METALLICITY THRESHOLDS

International Nuclear Information System (INIS)

Jappsen, Anne-Katharina; Low, Mordecai-Mark Mac; Glover, Simon C. O.; Klessen, Ralf S.; Kitsionas, Spyridon

2009-01-01

The formation of the first stars out of metal-free gas appears to result in stars at least an order of magnitude more massive than in the present-day case. We here consider what controls the transition from a primordial to a modern initial mass function. It has been proposed that this occurs when effective metal line cooling occurs at a metallicity threshold of Z/Z sun > 10 -3.5 . We study the influence of low levels of metal enrichment on the cooling and collapse of initially ionized gas in small protogalactic halos using three-dimensional, smoothed particle hydrodynamics simulations with particle splitting. Our initial conditions represent protogalaxies forming within a previously ionized H II region that has not yet had time to cool and recombine. These differ considerably from those used in simulations predicting a metallicity threshold, where the gas was initially cold and only partially ionized. In the centrally condensed potential that we study here, a wide variety of initial conditions for the gas yields a monolithic central collapse. Our models show no fragmentation during collapse to number densities as high as 10 5 cm -3 , for metallicities reaching as high as 10 -1 Z sun , far above the threshold suggested by previous work. Rotation allows for the formation of gravitationally stable gas disks over large fractions of the local Hubble time. Turbulence slows the growth of the central density slightly, but both spherically symmetric and turbulent initial conditions collapse and form a single sink particle. We therefore argue that fragmentation at moderate density depends on the initial conditions for star formation more than on the metal abundances present. The actual initial conditions to be considered still need to be determined in detail by observation and modeling of galaxy formation. Metal abundance may still drive fragmentation at very high densities due to dust cooling, perhaps giving an alternative metallicity threshold.

Stochastic calculus of protein filament formation under spatial confinement

Science.gov (United States)

Michaels, Thomas C. T.; Dear, Alexander J.; Knowles, Tuomas P. J.

2018-05-01

The growth of filamentous aggregates from precursor proteins is a process of central importance to both normal and aberrant biology, for instance as the driver of devastating human disorders such as Alzheimer's and Parkinson's diseases. The conventional theoretical framework for describing this class of phenomena in bulk is based upon the mean-field limit of the law of mass action, which implicitly assumes deterministic dynamics. However, protein filament formation processes under spatial confinement, such as in microdroplets or in the cellular environment, show intrinsic variability due to the molecular noise associated with small-volume effects. To account for this effect, in this paper we introduce a stochastic differential equation approach for investigating protein filament formation processes under spatial confinement. Using this framework, we study the statistical properties of stochastic aggregation curves, as well as the distribution of reaction lag-times. Moreover, we establish the gradual breakdown of the correlation between lag-time and normalized growth rate under spatial confinement. Our results establish the key role of spatial confinement in determining the onset of stochasticity in protein filament formation and offer a formalism for studying protein aggregation kinetics in small volumes in terms of the kinetic parameters describing the aggregation dynamics in bulk.

Central Asia, Euro-centrism and Colonialism

Directory of Open Access Journals (Sweden)

Nargis T. Nurulla-Khodzhaeva

2015-01-01

Full Text Available The following article should not be dismissed as yet another attempt to construct a renewed round ofrevisionism in history. On the contrary, it aims to explore the possibility of scaling down the dominant Eurocentric epistemology that served as a basis for a stereotypical frame of knowledge about Central Asia. The majority of researchers of the region do not deem the need to review the scale of contradictory clashes created by the notion of Eurocentrism. The latter is reflected in numerous articles about the frozen (and sadly deadlock dilemma on why and how were the lands of Tajiks, Uzbeks and Kazakhs divided. By publishing conventional analyses on the region's "clumsy separation", experts illustrate their subaltern, narrowly framed by the colonial world, knowledge and hence, remain as gravestones of the Eurocentric methodology. In the process of such explication, the most important role is allocated to the modern culture, which encouraged the formation of the paradox, represented to us via the paraphrased Soviet aphorism: modernity and coloniality are twin brothers. The initiation of the process of decolonizing the mind within the five republics of the region is possible. One of the solutions involves recognizing the integrity of the pluralist-cycled culture and philosophy of the region. The proposed act will allow shrinking the focus on the knowledge within the limited national units and frames (thus, lessening the degree of'fetishism of the national identity', and rather creating conditions for designing the "bridge", linking different cultures, ideologies and institutional spaces in Central Asia, as a transnational intellectual matrix. The aforementioned theory will provide a basis and structure for empirical facts, and, therefore, drive the researchers from merely constituting to critically thinking, and consequently, inspire to come upon new approaches and fields of study, connecting them with the existing, colonial experiences. It is

FORMATION AND RECONDENSATION OF COMPLEX ORGANIC MOLECULES DURING PROTOSTELLAR LUMINOSITY OUTBURSTS

International Nuclear Information System (INIS)

Taquet, Vianney; Wirström, Eva S.; Charnley, Steven B.

2016-01-01

During the formation of stars, the accretion of surrounding material toward the central object is thought to undergo strong luminosity outbursts followed by long periods of relative quiescence, even at the early stages of star formation when the protostar is still embedded in a large envelope. We investigated the gas-phase formation and recondensation of the complex organic molecules (COMs) di-methyl ether and methyl formate, induced by sudden ice evaporation processes occurring during luminosity outbursts of different amplitudes in protostellar envelopes. For this purpose, we updated a gas-phase chemical network forming COMs in which ammonia plays a key role. The model calculations presented here demonstrate that ion–molecule reactions alone could account for the observed presence of di-methyl ether and methyl formate in a large fraction of protostellar cores without recourse to grain-surface chemistry, although they depend on uncertain ice abundances and gas-phase reaction branching ratios. In spite of the short outburst timescales of about 100 years, abundance ratios of the considered species higher than 10% with respect to methanol are predicted during outbursts due to their low binding energies relative to water and methanol which delay their recondensation during cooling. Although the current luminosity of most embedded protostars would be too low to produce complex organics in the hot-core regions that are observable with current sub-millimetric interferometers, previous luminosity outburst events would induce the formation of COMs in extended regions of protostellar envelopes with sizes increasing by up to one order of magnitude

Formation and Recondensation of Complex Organic Molecules during Protostellar Luminosity Outbursts

Science.gov (United States)

Taquet, Vianney; Wirström, Eva S.; Charnley, Steven B.

2016-04-01

During the formation of stars, the accretion of surrounding material toward the central object is thought to undergo strong luminosity outbursts followed by long periods of relative quiescence, even at the early stages of star formation when the protostar is still embedded in a large envelope. We investigated the gas-phase formation and recondensation of the complex organic molecules (COMs) di-methyl ether and methyl formate, induced by sudden ice evaporation processes occurring during luminosity outbursts of different amplitudes in protostellar envelopes. For this purpose, we updated a gas-phase chemical network forming COMs in which ammonia plays a key role. The model calculations presented here demonstrate that ion-molecule reactions alone could account for the observed presence of di-methyl ether and methyl formate in a large fraction of protostellar cores without recourse to grain-surface chemistry, although they depend on uncertain ice abundances and gas-phase reaction branching ratios. In spite of the short outburst timescales of about 100 years, abundance ratios of the considered species higher than 10% with respect to methanol are predicted during outbursts due to their low binding energies relative to water and methanol which delay their recondensation during cooling. Although the current luminosity of most embedded protostars would be too low to produce complex organics in the hot-core regions that are observable with current sub-millimetric interferometers, previous luminosity outburst events would induce the formation of COMs in extended regions of protostellar envelopes with sizes increasing by up to one order of magnitude.

FORMATION AND RECONDENSATION OF COMPLEX ORGANIC MOLECULES DURING PROTOSTELLAR LUMINOSITY OUTBURSTS

Energy Technology Data Exchange (ETDEWEB)

Taquet, Vianney [Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands); Wirström, Eva S. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala (Sweden); Charnley, Steven B. [Astrochemistry Laboratory and The Goddard Center for Astrobiology, Mailstop 691, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20770 (United States)

2016-04-10

During the formation of stars, the accretion of surrounding material toward the central object is thought to undergo strong luminosity outbursts followed by long periods of relative quiescence, even at the early stages of star formation when the protostar is still embedded in a large envelope. We investigated the gas-phase formation and recondensation of the complex organic molecules (COMs) di-methyl ether and methyl formate, induced by sudden ice evaporation processes occurring during luminosity outbursts of different amplitudes in protostellar envelopes. For this purpose, we updated a gas-phase chemical network forming COMs in which ammonia plays a key role. The model calculations presented here demonstrate that ion–molecule reactions alone could account for the observed presence of di-methyl ether and methyl formate in a large fraction of protostellar cores without recourse to grain-surface chemistry, although they depend on uncertain ice abundances and gas-phase reaction branching ratios. In spite of the short outburst timescales of about 100 years, abundance ratios of the considered species higher than 10% with respect to methanol are predicted during outbursts due to their low binding energies relative to water and methanol which delay their recondensation during cooling. Although the current luminosity of most embedded protostars would be too low to produce complex organics in the hot-core regions that are observable with current sub-millimetric interferometers, previous luminosity outburst events would induce the formation of COMs in extended regions of protostellar envelopes with sizes increasing by up to one order of magnitude.

Outsourcing central banking

DEFF Research Database (Denmark)

Khoury, Sarkis Joseph; Wihlborg, Clas

2005-01-01

The literature on Currency Boards (CB) stops at the water edge in terms of dealing with the totality of the functions of a central bank. Monetary policy, and banking supervisioncan be "outsourced" in an open economy with substantial foreign direct investment (FDI)in the banking sector if political...... nationalism does not trump economic rationality. An orthodox CB renders the central banking function redundant in terms of interest rate and exchange rate determination. FDI in banking could perform the same role for the supervisory function of central banks. We use the case of Estonia to illustrate...... the feasibility of, and constraints on, outsourcing of central bank functions. A brief discussion of the Argentinian experience is used for contrast.Key words: Currency Board, Foreign Banks, Supervision, Regional Integration,outsourcing....

Galaxy formation

International Nuclear Information System (INIS)

Silk, J.; Di Cintio, A.; Dvorkin, I.

2014-01-01

Galaxy formation is at the forefront of observation and theory in cosmology. An improved understanding is essential for improving our knowledge both of the cosmological parameters, of the contents of the universe, and of our origins. In these lectures intended for graduate students, galaxy formation theory is reviewed and confronted with recent observational issues. In lecture 1, the following topics are presented: star formation considerations, including IMF, star formation efficiency and star formation rate, the origin of the galaxy luminosity function, and feedback in dwarf galaxies. In lecture 2, we describe formation of disks and massive spheroids, including the growth of supermassive black holes, negative feedback in spheroids, the AGN-star formation connection, star formation rates at high redshift and the baryon fraction in galaxies.

NIDDK Central Repository

Data.gov (United States)

U.S. Department of Health & Human Services — The NIDDK Central Repository stores biosamples, genetic and other data collected in designated NIDDK-funded clinical studies. The purpose of the NIDDK Central...

A novel bedside diagnostic test for methanol poisoning using dry chemistry for formate.

Science.gov (United States)

Hovda, Knut Erik; Gadeholt, Gaut; Evtodienko, Vladimir; Jacobsen, Dag

2015-11-01

The standard diagnostic approach to methanol poisoning is chromatographic measurement of methanol on centrally placed stationary equipment. Methanol poisoning in places where such equipment is unavailable is thus often not diagnosed. Methanol is metabolized to a toxic metabolite, formate; the presence of this compound indicates methanol poisoning. We have developed an enzymatic test for formate and modified it into a portable dry chemistry system that could be used anywhere. The method consists of two enzymatic steps: Formation of NADH from NAD by formate dehydrogenase, and subsequent use of NADH as a reductant of a tetrazolium into a formazan dye that can be quantified photometrically or visually. The photometer gave a good correlation of R(2) = 0.9893 in serum and R(2) = 0.9949 in whole blood, showing an instrumental detection limit of less than 1 mM (4.5 mg/dL). The visual readings showed a correlation of R(2) = 0.8966. Users experienced some difficulty in separating the negative control from the low positives. We have documented the feasibility of an affordable formate strip test for bedside diagnosis of methanol poisoning and for screening of metabolic acidosis of unknown origin. Visual reading is possible, but a reader will improve reliability at lower levels of formate. Future studies are necessary to study the sensitivity and specificity towards other causes of metabolic acidosis and other acids present in human blood.

Biostratigraphy of the Gurpi Formation in Zagros Basin, Iran

Directory of Open Access Journals (Sweden)

2015-10-01

Full Text Available Introdaction   The Gurpi Formation is developed in the central of the Zagros fold in Khuzestan, Lorestan and Fars provinces of southwestern Iran, defined az theZagros basin ,The Gurpi refers to Gurpi Mountain in the Kuzestan province.type section gurpi,which is N of the Lali oil wells and N-E of Masjed – Soleiman city,comprises 320m argillaceous limestone and gry-to-blueshale marl(James and Wynd,1965Although the boundary the Gurpi Formation and the underlying Ilam Formation is reported to be gradual,the altered facies found at this boundrary could be a sign of a low disconformity or even unconformity.In some place,the Ilam Formation does not exist and tne Gurpi Formation lie abave the Sarvak Formation.The upper boundry of the Gurpi Formation is more noticeable and there are different overlying formations.In Khozstan province,the Gurpi Formation is overlain by purplr shale of pabdeh Formation with signs of unconformity.The Gurpi Formation is not always concurrent. Biostratigraphy and lithological characteries of the Gurpi Formation were studied by James and Wynd (1965, Taheri (1998, KameliAzao (2002, Zarei (2005, Hematinasab (2008, Madavian (2009, Tavalaian (2011. This research study aims at describing the biostratigraphy of Gurpi Formation.In this study five stratigraphic section is investigate for its Planktonc Foraminiforal content.     Method and Matrials   This study involves five stratigraphic sections from the Gurpi Formation that were measured the ticknes and determind of Litostratigrapic limit as well as recognizd of detail litostrstigray the Gurpi Formation.More than 525 thine sections were examined. Some samples from the underlying Pabdeh Formation were also analysed for comparison. then recognizd Genus and species of Planktonic foraminifera and biozones mentioned wells have been introduced. In order to the biozonation of Gurpi Formation, stratigraphic distribution of well- known foraminifora is recognizd and then biozones are

Biostratigraphy of the Gurpi Formation in Zagros Basin, Iran

Directory of Open Access Journals (Sweden)

Abbas Sadeghi

2015-09-01

Full Text Available   Introdaction   The Gurpi Formation is developed in the central of the Zagros fold in Khuzestan, Lorestan and Fars provinces of southwestern Iran, defined az theZagros basin ,The Gurpi refers to Gurpi Mountain in the Kuzestan province.type section gurpi,which is N of the Lali oil wells and N-E of Masjed – Soleiman city,comprises 320m argillaceous limestone and gry-to-blueshale marl(James and Wynd,1965Although the boundary the Gurpi Formation and the underlying Ilam Formation is reported to be gradual,the altered facies found at this boundrary could be a sign of a low disconformity or even unconformity.In some place,the Ilam Formation does not exist and tne Gurpi Formation lie abave the Sarvak Formation.The upper boundry of the Gurpi Formation is more noticeable and there are different overlying formations.In Khozstan province,the Gurpi Formation is overlain by purplr shale of pabdeh Formation with signs of unconformity.The Gurpi Formation is not always concurrent. Biostratigraphy and lithological characteries of the Gurpi Formation were studied by James and Wynd (1965, Taheri (1998, KameliAzao (2002, Zarei (2005, Hematinasab (2008, Madavian (2009, Tavalaian (2011. This research study aims at describing the biostratigraphy of Gurpi Formation.In this study five stratigraphic section is investigate for its Planktonc Foraminiforal content.     Method and Matrials   This study involves five stratigraphic sections from the Gurpi Formation that were measured the ticknes and determind of Litostratigrapic limit as well as recognizd of detail litostrstigray the Gurpi Formation.More than 525 thine sections were examined. Some samples from the underlying Pabdeh Formation were also analysed for comparison. then recognizd Genus and species of Planktonic foraminifera and biozones mentioned wells have been introduced. In order to the biozonation of Gurpi Formation, stratigraphic distribution of well- known foraminifora is recognizd and

The central amygdala circuits in fear regulation

Science.gov (United States)

Li, Bo

The amygdala is essential for fear learning and expression. The central amygdala (CeA), once viewed as a passive relay between the amygdala complex and downstream fear effectors, has emerged as an active participant in fear conditioning. However, how the CeA contributes to the learning and expression of fear remains unclear. Our recent studies in mice indicate that fear conditioning induces robust plasticity of excitatory synapses onto inhibitory neurons in the lateral subdivision of CeA (CeL). In particular, this plasticity is cell-type specific and is required for the formation of fear memory. In addition, sensory cues that predict threat can cause activation of the somatostatin-positive CeL neurons, which is sufficient to drive freezing behavior. Here I will report our recent findings regarding the circuit and cellular mechanisms underlying CeL function in fear processing.

The dynamics of fragment formation

International Nuclear Information System (INIS)

Keane, D.

1994-09-01

We demonstrate that in the Quantum Molecular Dynamics model, dynamical correlations can result in the production rate for final state nucleon clusters (and hence composite fragments) being higher than would be expected if statistics and the available phase space were dominant in determining composite formation. An intranuclear cascade or a Boltzmann-Uehling-Uhlenbeck model, combined with a statistical approach in the late stage of the collision to determine composites, provides an equivalent description only under limited conditions of centrality and beam energy. We use data on participant fragment production in Au + Au collisions in the Bevalac's BOS time projection chamber to map out the parameter space where statistical clustering provides a good description. In particular, we investigate momentum-space densities of fragments up to 4 He as a function of fragment transverse momentum, azimuth relative to the reaction plane, rapidity, multiplicity and beam energy

Digitization, correction, and standardization of geophysical logs from deep boreholes of Central New York State. Final technical report

International Nuclear Information System (INIS)

Robinson, J.E.

1981-07-01

Digitization and standardization of suitable logs are provided from wells located in the area of Central New York that had been under consideration as a possible site for the disposal of radioactive waste. Digitized logs included those with geophysical parameters that could be analyzed for formation porosity and lithology and in which the log interval was sufficient to evaluate formation parameters. Digitizing equipment was purchased, interfaced, and necessary software was written and documented. Magnetic tapes and hard copy playbacks of all digitized well logs are being forwarded to the Department of Energy repository at Battelle Memorial Institute for use in future projects

CENTRAL PLATEAU REMEDIATION

International Nuclear Information System (INIS)

ROMINE, L.D.

2006-01-01

A systematic approach to closure planning is being implemented at the Hanford Site's Central Plateau to help achieve the goal of closure by the year 2035. The overall objective of Central Plateau remediation is to protect human health and the environment from the significant quantity of contaminated material that resulted from decades of plutonium production in support of the nation's defense. This goal will be achieved either by removing contaminants or placing the residual contaminated materials in a secure configuration that minimizes further migration to the groundwater and reduces the potential for inadvertent intrusion into contaminated sites. The approach to Central Plateau cleanup used three key concepts--closure zones, closure elements, and closure process steps--to create an organized picture of actions required to complete remediation. These actions were merged with logic ties, constraints, and required resources to produce an integrated time-phased schedule and cost profile for Central Plateau closure. Programmatic risks associated with implementation of Central Plateau closure were identified and analyzed. Actions to mitigate the most significant risks are underway while high priority remediation projects continue to make progress

A new avian fauna from the early-middle Eocene Lillebælt Clay Formation of Denmark

DEFF Research Database (Denmark)

Lindow, Bent Erik Kramer

A number of hitherto undescribed fossil bird remains have been recovered from the Lillebælt Clay Formation of central Denmark, which is early-middle Eocene in age (~50 to 43 mya). The core of the material consists of fossils acquired through the Danish ‘Danekræ' fossil treasure trove legislation......, a member of the extinct 'pseudo-toothed birds' and the first representative of this group known from Denmark. Other taxa present include remains of Lithornithidae and a new taxon possessing a massive, psittacid-like beak. The Lillebælt Clay Formation birds are temporally placed just after the Early Eocene...

Formation and thermodynamic stability of (polymer + porphyrin) supramolecular structures in aqueous solutions

International Nuclear Information System (INIS)

Costa, Viviana C.P. da; Hwang, Barrington J.; Eggen, Spencer E.; Wallace, Megan J.; Annunziata, Onofrio

2014-01-01

Highlights: • Thermodynamic stability of a (polymer + porphyrin) supramolecular structure was characterized. • Isothermal titration calorimetry provided two ways to determine reaction enthalpies. • Exothermic (polymer + porphyrin) binding competes with porphyrin self-association. • (Polymer + porphyrin) binding is entropically favored with respect to porphyrin self-association. • Spectral shifts show importance of porphyrin central hydrogens in polymer binding. - Abstract: Optical properties of porphyrins can be tuned through (polymer + porphyrin) (host + guest) binding in solution. This gives rise to the formation of supramolecular structures. In this paper, the formation, thermodynamic stability and spectroscopic properties of (polymer + porphyrin) supramolecular structures and their competition with porphyrin self-association were investigated by both isothermal titration calorimetry (ITC) and absorption spectroscopy. Specifically, reaction enthalpies and equilibrium constants were measured for meso-tetrakis(4-sulfonatophenyl) porphyrin (TPPS) self-association and TPPS binding to the polymer poly(vinylpyrrolidone) (PVP, 40 kg/mol) in aqueous solutions at pH 7 and three different temperatures (12, 25 and 37 °C). ITC, compared to spectroscopic techniques, provides two independent means to determine reaction enthalpies: direct measurements and Van’t Hoff plot. This was used as a criterion to assess that (1) self-association of TPPS is limited to the formation of dimers and (2) TPPS binds to PVP in its monomeric state only. The formation of TPPS dimers and (PVP + TPPS) supramolecular structures are both enthalpically driven. However, (polymer + porphyrin) binding was found to be entropically favored compared to dimerization. Furthermore, the reaction enthalpies of these two processes significantly depend on temperature. This behavior was attributed to hydrophobic interactions. Finally, the limiting absorption spectra of monomeric, dimeric and polymer

Spatial Databases of Geological, Geophysical, and Mineral Resource Data Relevant to Sandstone-Hosted Copper Deposits in Central Kazakhstan

Science.gov (United States)

Syusyura, Boris; Box, Stephen E.; Wallis, John C.

2010-01-01

Central Kazakhstan is host to one of the world's giant sandstone-hosted copper deposits, the Dzhezkazgan deposit, and several similar, smaller deposits. The United Stated Geological Survey (USGS) is assessing the potential for other, undiscovered deposits of this type in the surrounding region of central Kazakhstan. As part of this effort, Syusyura compiled and partially translated an array of mostly unpublished geologic, geophysical, and mineral resource data for this region in digital format from the archives of the former Union of Soviet Socialists Republics (of which Kazakhstan was one of the member republics until its dissolution in 1991), as well as from later archives of the Republic of Kazakhstan or of the Kazakhstan consulting firm Mining Economic Consulting (MEC). These digital data are primarily map-based displays of information that were transmitted either in ESRI ArcGIS, georeferenced format, or non-georeferenced map image files. Box and Wallis reviewed all the data, translated Cyrillic text where necessary, inspected the maps for consistency, georeferenced the unprojected map images, and reorganized the data into the filename and folder structure of this publication.

A roe deer from the Pliocene of Hidalgo, central Mexico

Directory of Open Access Journals (Sweden)

Eduardo Jiménez-Hidalgo

2015-12-01

Full Text Available Mexican Pliocene cervids are very poorly known. We report on new fossil material of the roe deer Capreolus constantini recovered from the Pliocene Atotonilco El Grande Formation of Santa María Amajac, Hidalgo (central Mexico. The specimens were collected from a series of layers of friable to moderately indurated polymictic conglomerate supported by a sandstone-tuffaceous-calcareous matrix. This species was formerly known only from the late Pliocene of Udunga, Russia, thus implying a dispersal event to North America around 4.0 Ma. This cervid is one of the very small number of mammals recorded from the poorly sampled Pliocene temperate deposits of Mexico.

Aggresome formation is regulated by RanBPM through an interaction with HDAC6

Directory of Open Access Journals (Sweden)

Louisa M. Salemi

2014-05-01

Full Text Available In conditions of proteasomal impairment, the build-up of damaged or misfolded proteins activates a cellular response leading to the recruitment of damaged proteins into perinuclear aggregates called aggresomes. Aggresome formation involves the retrograde transport of cargo proteins along the microtubule network and is dependent on the histone deacetylase HDAC6. Here we show that ionizing radiation (IR promotes Ran-Binding Protein M (RanBPM relocalization into discrete perinuclear foci where it co-localizes with aggresome components ubiquitin, dynein and HDAC6, suggesting that the RanBPM perinuclear clusters correspond to aggresomes. RanBPM was also recruited to aggresomes following treatment with the proteasome inhibitor MG132 and the DNA-damaging agent etoposide. Strikingly, aggresome formation by HDAC6 was markedly impaired in RanBPM shRNA cells, but was restored by re-expression of RanBPM. RanBPM was found to interact with HDAC6 and to inhibit its deacetylase activity. This interaction was abrogated by a RanBPM deletion of its LisH/CTLH domain, which also prevented aggresome formation, suggesting that RanBPM promotes aggresome formation through an association with HDAC6. Our results suggest that RanBPM regulates HDAC6 activity and is a central regulator of aggresome formation.

The Albian oceanic anoxic events record in central and northern Tunisia: Geochemical data and paleotectonic controls

OpenAIRE

Khalifa , Zina; Affouri , Hassene; Rigane , Adel; Jacob , Jérémy

2018-01-01

International audience; The Albian organic-rich successions of the lower part of the Fahdene Formation (Albian to Cenomanian, Tunisia) were studied using sedimentology (analysis of carbonate contents and observation of thin sections), bulk organic geochemistry (Rock-Eval pyrolysis), and molecular biomarker distributions. The selected outcrops cover different structural domains from western central Tunisia (Jebel Hamra) to the Diapir zone or the Tunisian Trough (Koudiat Berkouchia, Jebel Ghazo...

Probing the formation history of the nuclear star cluster at the Galactic Centre with millisecond pulsars

Science.gov (United States)

Abbate, F.; Mastrobuono-Battisti, A.; Colpi, M.; Possenti, A.; Sippel, A. C.; Dotti, M.

2018-01-01

The origin of the nuclear star cluster in the centre of our Galaxy is still unknown. One possibility is that it formed after the disruption of stellar clusters that spiralled into the Galactic Centre due to dynamical friction. We trace the formation of the nuclear star cluster around the central black hole, using state-of-the-art N-body simulations, and follow the dynamics of the neutron stars born in the clusters. We then estimate the number of millisecond pulsars (MSPs) that are released in the nuclear star cluster during its formation. The assembly and tidal dismemberment of globular clusters lead to a population of MSPs distributed over a radius of about 20 pc, with a peak near 3 pc. No clustering is found on the subparsec scale. We simulate the detectability of this population with future radio telescopes like the MeerKAT radio telescope and SKA1, and find that about an order of 10 MSPs can be observed over this large volume, with a paucity of MSPs within the central parsec. This helps discriminating this scenario from the in situ formation model for the nuclear star cluster that would predict an overabundance of MSPs closer to the black hole. We then discuss the potential contribution of our MSP population to the gamma-ray excess at the Galactic Centre.

Deformational and erosional history for the Abiquiu and contiguous area, north-central New Mexico: Implications for formation of the Abiquiu embayment and a discussion of new geochronological and geochemical analysis

Science.gov (United States)

Maldonado, Florian; Miggins, Daniel P.; Budahm, James R.

2013-01-01

Geologic mapping, age determinations, and geochemistry of rocks exposed in the Abiquiu area of the Abiquiu embayment of the Rio Grande rift, north-central New Mexico, provide data to determine fault-slip and incision rates. Vertical-slip rates for faults in the area range from 16 m/m.y. to 42 m/m.y., and generally appear to decrease from the eastern edge of the Colorado Plateau to the Abiquiu embayment. Incision rates calculated for the period ca. 10 to ca. 3 Ma indicate rapid incision with rates that range from 139 m/m.y. on the eastern edge of the Colorado Plateau to 41 m/m.y. on the western part of the Abiquiu embayment.The Abiquiu area is located along the margin of the Colorado Plateau–Rio Grande rift and lies within the Abiquiu embayment, a shallow, early extensional basin of the Rio Grande rift. Cenozoic rocks include the Eocene El Rito Formation, Oligocene Ritito Conglomerate, Oligocene–Miocene Abiquiu Formation, and Miocene Chama–El Rito and Ojo Caliente Sandstone Members of the Tesuque Formation (Santa Fe Group). Volcanic rocks include the Lobato Basalt (Miocene; ca. 15–8 Ma), El Alto Basalt (Pliocene; ca. 3 Ma), and dacite of the Tschicoma Formation (Pliocene; ca. 2 Ma). Quaternary deposits consist of inset axial and side-stream deposits of the ancestral Rio Chama (Pleistocene in age), landslide and pediment alluvium and colluvium, and Holocene main and side-stream channel and floodplain deposits of the modern Rio Chama. The predominant faults are Tertiary normal high-angle faults that displace rocks basinward.A low-angle fault, referred to as the Abiquiu fault, locally separates an upper plate composed of the transitional zone of the Ojo Caliente Sandstone and Chama–El Rito Members from a lower plate consisting of the Abiquiu Formation or the Ritito Conglomerate. The upper plate is distended into blocks that range from about 0.1 km to 3.5 km long that may represent a larger sheet that has been broken up and partly eroded.Geochronology (40Ar/39

Mangiferin Upregulates Glyoxalase 1 Through Activation of Nrf2/ARE Signaling in Central Neurons Cultured with High Glucose.

Science.gov (United States)

Liu, Yao-Wu; Cheng, Ya-Qin; Liu, Xiao-Li; Hao, Yun-Chao; Li, Yu; Zhu, Xia; Zhang, Fan; Yin, Xiao-Xing

2017-08-01

Mangiferin, a natural C-glucoside xanthone, has anti-inflammatory, anti-oxidative, neuroprotective actions. Our previous study showed that mangiferin could attenuate diabetes-associated cognitive impairment of rats by enhancing the function of glyoxalase 1 (Glo-1) in brain. The aim of this study was to investigate whether Glo-1 upregulation by mangiferin in central neurons exposed to chronic high glucose may be related to activation of Nrf2/ARE pathway. Compared with normal glucose (25 mmol/L) culture, Glo-1 protein, mRNA, and activity levels were markedly decreased in primary hippocampal and cerebral cortical neurons cultured with high glucose (50 mmol/L) for 72 h, accompanied by the declined Nrf2 nuclear translocation and protein expression of Nrf2 in cell nucleus, as well as protein expression and mRNA level of γ-glutamylcysteine synthetase (γ-GCS) and superoxide dismutase activity, target genes of Nrf2/ARE signaling. Nonetheless, high glucose cotreating with mangiferin or sulforaphane, a typical inducer of Nrf2 activation, attenuated the above changes in both central neurons. In addition, mangiferin and sulforaphane significantly prevented the formation of advanced glycation end-products (AGEs) reflecting Glo-1 activity, while elevated the level of glutathione, a cofactor of Glo-1 activity and production of γ-GCS, in high glucose cultured central neurons. These findings demonstrated that Glo-1 was greatly downregulated in central neurons exposed to chronic high glucose, which is expected to lead the formation of AGEs and oxidative stress damages. We also proved that mangiferin enhanced the function of Glo-1 under high glucose condition by inducing activation of Nrf2/ARE signaling pathway.

ADAPTIVE MESH REFINEMENT SIMULATIONS OF GALAXY FORMATION: EXPLORING NUMERICAL AND PHYSICAL PARAMETERS

International Nuclear Information System (INIS)

Hummels, Cameron B.; Bryan, Greg L.

2012-01-01

We carry out adaptive mesh refinement cosmological simulations of Milky Way mass halos in order to investigate the formation of disk-like galaxies in a Λ-dominated cold dark matter model. We evolve a suite of five halos to z = 0 and find a gas disk formation in each; however, in agreement with previous smoothed particle hydrodynamics simulations (that did not include a subgrid feedback model), the rotation curves of all halos are centrally peaked due to a massive spheroidal component. Our standard model includes radiative cooling and star formation, but no feedback. We further investigate this angular momentum problem by systematically modifying various simulation parameters including: (1) spatial resolution, ranging from 1700 to 212 pc; (2) an additional pressure component to ensure that the Jeans length is always resolved; (3) low star formation efficiency, going down to 0.1%; (4) fixed physical resolution as opposed to comoving resolution; (5) a supernova feedback model that injects thermal energy to the local cell; and (6) a subgrid feedback model which suppresses cooling in the immediate vicinity of a star formation event. Of all of these, we find that only the last (cooling suppression) has any impact on the massive spheroidal component. In particular, a simulation with cooling suppression and feedback results in a rotation curve that, while still peaked, is considerably reduced from our standard runs.

Strain distribution and model for formation of eastern Umtanum Ridge anticline, south-central Washington

Energy Technology Data Exchange (ETDEWEB)

Price, E.H.

1979-10-01

Umtanum Ridge in south-central Washington is the topographic expression of a complex anticline within the Yakima Fold system in the Miocene Columbia River Basalt Group. The Yakima Fold system, which is partly contained within the Hanford Site, is an example of a layered basalt sequence folded near the surface of the earth. The Pasco Basin stratigraphic nomenclature is used in this repot. Rockwelll Hanford Operations, under contract to the US Department of Energy, is investigating the feasibility of therminal high-level nuclear waste storage in mined repositories in basalt beneath the Hanford Site. Because thereis essentially no basalt within the Site that has not been involved in some folding, any potential location for a repository will be either on the limbs or near the hinge zone of a Yakima Fold structure. Umtanum Ridge is the best exposed Yakima Fold structure in the vicinity of the Site for studying the nature and three-dimensional style of deformation of a multilayered basalt sequence. The structural geometry, distribution of strain within the Umtanum structure and deformational mechanisms of the Umtanum Ridge are discussed.

Strain distribution and model for formation of eastern Umtanum Ridge anticline, south-central Washington

International Nuclear Information System (INIS)

Price, E.H.

1979-10-01

Umtanum Ridge in south-central Washington is the topographic expression of a complex anticline within the Yakima Fold system in the Miocene Columbia River Basalt Group. The Yakima Fold system, which is partly contained within the Hanford Site, is an example of a layered basalt sequence folded near the surface of the earth. The Pasco Basin stratigraphic nomenclature is used in this repot. Rockwelll Hanford Operations, under contract to the US Department of Energy, is investigating the feasibility of therminal high-level nuclear waste storage in mined repositories in basalt beneath the Hanford Site. Because thereis essentially no basalt within the Site that has not been involved in some folding, any potential location for a repository will be either on the limbs or near the hinge zone of a Yakima Fold structure. Umtanum Ridge is the best exposed Yakima Fold structure in the vicinity of the Site for studying the nature and three-dimensional style of deformation of a multilayered basalt sequence. The structural geometry, distribution of strain within the Umtanum structure and deformational mechanisms of the Umtanum Ridge are discussed

THE PECULIAR PULSAR POPULATION OF THE CENTRAL PARSEC

Energy Technology Data Exchange (ETDEWEB)

Dexter, Jason; O' Leary, Ryan M., E-mail: jdexter@berkeley.edu, E-mail: oleary@berkeley.edu [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

2014-03-01

Pulsars orbiting the Galactic center black hole, Sgr A*, would be potential probes of its mass, distance, and spin, and may even be used to test general relativity. Despite predictions of large populations of both ordinary and millisecond pulsars in the Galactic center, none have been detected within 25 pc by deep radio surveys. One explanation has been that hyperstrong temporal scattering prevents pulsar detections, but the recent discovery of radio pulsations from a highly magnetized neutron star (magnetar) within 0.1 pc shows that the temporal scattering is much weaker than predicted. We argue that an intrinsic deficit in the ordinary pulsar population is the most likely reason for the lack of detections to date: a ''missing pulsar problem'' in the Galactic center. In contrast, we show that the discovery of a single magnetar implies efficient magnetar formation in the region. If the massive stars in the central parsec form magnetars rather than ordinary pulsars, their short lifetimes could explain the missing pulsars. Efficient magnetar formation could be caused by strongly magnetized progenitors, or could be further evidence of a top-heavy initial mass function. Furthermore, current high-frequency surveys should already be able to detect bright millisecond pulsars, given the measured degree of temporal scattering.

Hydrocarbon Potential in Sandstone Reservoir Isolated inside Low Permeability Shale Rock (Case Study: Beruk Field, Central Sumatra Basin)

Science.gov (United States)

Diria, Shidqi A.; Musu, Junita T.; Hasan, Meutia F.; Permono, Widyo; Anwari, Jakson; Purba, Humbang; Rahmi, Shafa; Sadjati, Ory; Sopandi, Iyep; Ruzi, Fadli

2018-03-01

Upper Red Bed, Menggala Formation, Bangko Formation, Bekasap Formation and Duri Formationare considered as the major reservoirs in Central Sumatra Basin (CSB). However, Telisa Formation which is well-known as seal within CSB also has potential as reservoir rock. Field study discovered that lenses and layers which has low to high permeability sandstone enclosed inside low permeability shale of Telisa Formation. This matter is very distinctive and giving a new perspective and information related to the invention of hydrocarbon potential in reservoir sandstone that isolated inside low permeability shale. This study has been conducted by integrating seismic data, well logs, and petrophysical data throughly. Facies and static model are constructed to estimate hydrocarbon potential resource. Facies model shows that Telisa Formation was deposited in deltaic system while the potential reservoir was deposited in distributary mouth bar sandstone but would be discontinued bedding among shale mud-flat. Besides, well log data shows crossover between RHOB and NPHI, indicated that distributary mouth bar sandstone is potentially saturated by hydrocarbon. Target area has permeability ranging from 0.01-1000 mD, whereas porosity varies from 1-30% and water saturation varies from 30-70%. The hydrocarbon resource calculation approximates 36.723 MSTB.

Full-Thickness Retinochoroidal Incision in the Management of Central Retinal Vein Occlusion

Directory of Open Access Journals (Sweden)

San-Ni Chen

2015-01-01

Full Text Available Purpose. To evaluate the clinical outcomes in patients with central retinal vein occlusion (CRVO treated with full-thickness retinochoroidal incisions and to compare whether there is difference in treatment response in ischemic and nonischemic CRVO. Methods. Retrospective study of patients of CRVO receiving full-thickness retinochoroidal incisions in Changhua Christian Hospital. Fluorescein angiography (FA, slit-lamp biomicroscopy, indirect funduscopy, best corrected visual acuity, and central macular thickness (CMT measured by optical coherence tomography were performed pre- and postoperatively. Patients were divided into an ischemic and nonischemic group according to the findings of FA. Patients were followed up for at least 1 year. Results. Twenty-eight eyes (14 ischemic and 14 nonischemic CRVO were included. Functional retinochoroidal venous anastomosis (RCVA was achieved in 48 of the 65 retinochoroidal incisions (73.8%. Central macular thickness (CMT and retinal hemorrhage decreased significantly after the surgery. Significant visual gain was observed postoperatively in the nonischemic group, but not in the ischemic group. Postoperative complications included vitreous hemorrhage (17.8%, neovascular glaucoma (7.1%, and preretinal fibrovasular membrane (10.7%, all of which were in the ischemic group. Conclusions. RCVA formation induced by retinochoroidal incisions could improve venous flow, and decrease CMT and retinal hemorrhage. However, only eyes with nonischemic CRVO showed visual improvement.

Detailed geochemical survey for east-central Minnesota, geology and geochemistry of selected uranium targets

International Nuclear Information System (INIS)

Morey, G.B.; Lively, R.S.

1980-01-01

Results of a detailed geochemical survey of approximately 6820 km 2 in parts of Aitkin, Carlton, Kanabec, and Pine Counties, east-central Minnesota are reported. Geochemical data are presented for 883 groundwater samples and 200 bedrock samples. Although all of the groundwaters in the study area have similar major-element concentrations and therefore presumably a common ancestry, small differences in the minor-element concentrations serve to characterize various aquifers, both in the Quaternary deposits and in the bedrock. All of the aquifers locally yield waters having statistically anomalous concentrations of uranium or radon, but these anomalies are spatially coincident only in a few places and particularly in three geologic environments considered favorable for uranium mineralization. These include the following: (1) Thomson Formation near the unconformably overlying Fond du Lac Formation, (2) Hinckley Sandstone near a major fault system, and (3) Denham Formation near the unconformity with the McGrath Gneiss, particularly where these rocks are faulted and overlain by the Fond du Lac Formation. One additional uranium environment characterized by thin laminae of uraniferous apatite was located in the Thomson Formation during outcrop reconnaissance and sampling. The coincidence of this and other anomalously high uranium values in the bedrock with specific uranium and radon anomalies in the groundwater confirms the usefulness of the hydrogeochemical data to uranium exploration in this glaciated terrane

Actual versus Perceived Central Bank Transparency : The Case of the European Central Bank

NARCIS (Netherlands)

van der Cruijsen, C.A.B.; Eijffinger, S.C.W.

2007-01-01

Central banks have become more and more transparent about their monetary policy making process. In the central bank transparency lit- erature the distinction between actual and perceived central bank trans- parency is often lacking. However, as perceptions are crucial for the ac- tions of economic

Stellar formation

CERN Document Server

Reddish, V C

1978-01-01

Stellar Formation brings together knowledge about the formation of stars. In seeking to determine the conditions necessary for star formation, this book examines questions such as how, where, and why stars form, and at what rate and with what properties. This text also considers whether the formation of a star is an accident or an integral part of the physical properties of matter. This book consists of 13 chapters divided into two sections and begins with an overview of theories that explain star formation as well as the state of knowledge of star formation in comparison to stellar structure

Comparative ecobalancing accounting of semi-central house heat supply from wood residues; Vergleichende Oekobilanzierung der semi-zentralen Hauswaermebereitstellung aus Holzreststoffen

Energy Technology Data Exchange (ETDEWEB)

Biemann, Kirsten

2015-07-01

impact. Heat demanders and network structure vary for the different settlement types. This impacts the heat losses and the amount of energy generated from wood in the network. Combined heat and power plants promise higher fuel utilization. They decrease costs and environmental impacts. The heat losses in the network vary greatly between 23 percent for small single-family houses and 4 percent for big multi-family buildings. Therefore networks with bigger heat demanders have lower environmental burdens. From an economic point of view the conversion from a gas heater to the connection of a multi- family building to a semi- centralized heating network using wood residues as fuel is worthwhile. However for a single-family building this is often not the case. A comparison between the semi- centralized heat supply from wood residues and the commonly used heat supply from gas heaters shows a large potential to decrease greenhouse gas emissions, ozone depletion and fossil resource usage when using the first variant. However, it increases particulate matter formation, photochemical oxidant formation, eutrophication, and acidification. Only the usage of a wood gasification and a combined heat and power plant decreases particulate matter formation slightly. Similar results were obtained for a centralized heating network using wood residues as fuel. Using wood heaters in the buildings further decreases greenhouse gas emissions, ozone depletion and fossil resources, but results in an increased particulate matter formation. This particulate matter formation is over 1.000 percent bigger than for gas heaters.

TERRAIN TECTONICS OF THE CENTRAL ASIAN FOLDED BELT

Directory of Open Access Journals (Sweden)

M. M. Buslov

2014-01-01

Full Text Available The terrain analysis concept envisages primarily a possibility of approximation of fragments / terrains of various geodynamic settings which belong to different plates. The terrain analysis can supplement the theory of plate tectonics in solving problems of geodynamics and tectonics of regions of the crust with complex structures. The Central Asian belt is among such complicated regions. Terrain structures occurred as a result of combined movements in the system of 'frontal' and/or oblique subduction – collision. In studies of geological objects, it is required first of all to prove their (vertical and horizontal autochthony in relations to each other and then proceed to paleogeodynamic, paleotectonic and paleogeographic reconstructions. Obviously, such a complex approach needs data to be obtained by a variety of research methods, including those applied to study geologic structures, stratigraphy, paleontology, paleogeography, lithothlogy, geochemistry, geochronology, paleomagnetism etc. Only by correlating such data collected from inter-disciplinary studies of the regions, it is possible to establish reliable characteristics of the geological settings and avoid mistakes and misinterpretations that may be associated with the 'stratigraphic' approach to solutions of both regional and global problems of geodynamics and tectonics of folded areas. The terrain analysis of the Central Asian folded belt suggests that its tectonic structure combines marginal continental rock complexes that were formed by the evolution of two major oceanic plates. One of them is the plate of the Paleo-Asian Ocean. As the analogue of the current Indo-Atlantic segment of Earth, it is characterised by the presence of continental blocks in the composition of the oceanic crust and the formation of oceanic basins resulting from the breakup of Rodinia and Gondvana. In the course of its evolution, super-continents disintegrated, and the blocks were reunited into the Kazakhstan

PREFACE: Astronomy at High Angular Resolution 2011: The central kiloparsec in galactic nuclei

Science.gov (United States)

Iserlohe, Christof; Karas, Vladimir; Krips, Melanie; Eckart, Andreas; Britzen, Silke; Fischer, Sebastian

2012-07-01

We are pleased to present the proceedings from the Astronomy at High Angular Resolution 2011: The central kiloparsec in galactic nuclei conference. The conference took place in the Physikzentrum of the Deutsche Physikalische Gesellschaft (DPG), Bad Honnef, Germany, from 28 August to 2 September 2011. It was the second conference of this kind, following the Astronomy at High Angular Resolution conference held in Bad Honnef, three years earlier in 2008. The main objective of the conference was to frame the discussion of the broad range of physical processes that occur in the central 100pc of galactic nuclei. In most cases, this domain is difficult to probe through observations. This is mainly because of the lack of angular resolution, the brightness of the central engine and possible obscurations through dust and gas, which play together in the central regions of host galaxies of galactic nuclei within a broad range of activity. The presence of large amounts of molecular and atomic (both neutral and ionized) gas, dust and central engines with outflows and jets implies that the conditions for star formation in these regions are very special, and probably different from those in the disks of host galaxies. Numerous presentations covering a broad range of topics, both theoretical and experimental, those related to research on Active Galactic Nuclei and on a wide range of observed wavelengths were submitted to the Scientific Organizing Committee. Presentations have been grouped into six sessions: The nuclei of active galaxies The Galactic Center The immediate environment of Super Massive Black Holes The physics of nuclear jets and the interaction of the interstellar medium The central 100pc of the nuclear environment Star formation in that region The editors thank all participants of the AHAR 2011 conference for their enthusiasm and their numerous and vivid contributions to this conference. We would especially like to thank John Hugh Seiradakis from the Aristotle

Q-profile requirements for electro ITB formation

Energy Technology Data Exchange (ETDEWEB)

Goodman, T. P.; Coda, S.; Henderson, M. A.; Sauter, O.; Behn, R.; Bottino, A.; Fable, E.; Martynov, A.; Nikkola, P.; Zucca, C.

2005-07-01

The formation requirements of ITBs on numerous tokamaks have been correlated with either a power threshold, appearance of a low order rational surface near q{sub m}in or q{sub 9}5, weak or negative shear, etc. On TCV, electron ITBs (eITBs) can be formed during a gradual evolution from a centrally peaked to hollow current profile while all external actuators are held constant. The formation occurs rapidly (<{tau}{sub e}E) and locally and, according to ASTRA modeling, is correlated with the appearance of a local minimum in the q-profile. There is no clear evidence that the minimum in q appears at a low order rational. These eITBs are sustained by non-inductively driven current (ECCD and bootstrap current) while the current in the tokamak transformer is beld constant. Thus, they are not inherently transient but can exist for several current redistribution times; limited only by the pulse length of the gyrotrons. After the barrier is formed, the gransformer coil can be used as a counter (or co-) current source with negligible accompanying input power. The eITB performance can be enhanced (degraded) by altering solely the current or q-profile: when negative (positive) inductive current is driven, the on-axis current density decreases (increases) resulting in a stronger (weaker) reversed shear as both the ECCD and bootstrap currents are peaked off-axis. These experiments provide a unique realm of eITB formation and performance characteristics that can be used to isolate the physics criteria governing the eITB. (Author)

Public accessibility of biomedical articles from PubMed Central reduces journal readership--retrospective cohort analysis.

Science.gov (United States)

Davis, Philip M

2013-07-01

Does PubMed Central--a government-run digital archive of biomedical articles--compete with scientific society journals? A longitudinal, retrospective cohort analysis of 13,223 articles (5999 treatment, 7224 control) published in 14 society-run biomedical research journals in nutrition, experimental biology, physiology, and radiology between February 2008 and January 2011 reveals a 21.4% reduction in full-text hypertext markup language (HTML) article downloads and a 13.8% reduction in portable document format (PDF) article downloads from the journals' websites when U.S. National Institutes of Health-sponsored articles (treatment) become freely available from the PubMed Central repository. In addition, the effect of PubMed Central on reducing PDF article downloads is increasing over time, growing at a rate of 1.6% per year. There was no longitudinal effect for full-text HTML downloads. While PubMed Central may be providing complementary access to readers traditionally underserved by scientific journals, the loss of article readership from the journal website may weaken the ability of the journal to build communities of interest around research papers, impede the communication of news and events to scientific society members and journal readers, and reduce the perceived value of the journal to institutional subscribers.

Interns reflect: the effect of formative assessment with feedback during pre-internship

OpenAIRE

McKenzie, Susan; Burgess, Annette; Mellis, Craig

2017-01-01

Susan McKenzie,1 Annette Burgess,2 Craig Mellis1 1Central Clinical School, 2Education Office, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia Background: It is widely known that the opportunity for medical students to be observed and to receive feedback on their procedural skills performance is variable in the senior years. To address this problem, we provided our Pre-Intern (PrInt) students with “one-to-one” formative feedback on their ability to p...

Protocol for Communication Networking for Formation Flying

Science.gov (United States)

Jennings, Esther; Okino, Clayton; Gao, Jay; Clare, Loren

2009-01-01

diverse local-area networks, this protocol offers both (1) a random- access mode needed for the early PFF deployment phase and (2) a time-bounded-services mode needed during PFF-maintenance operations. Switching between these two modes could be controlled by upper-layer entities using standard link-management mechanisms. Because the early deployment phase of a PFF mission can be expected to involve multihop relaying to achieve network connectivity (see figure), the proposed protocol includes the open shortest path first (OSPF) network protocol that is commonly used in the Internet. Each spacecraft in a PFF network would be in one of seven distinct states as the mission evolved from initial deployment, through coarse formation, and into precise formation. Reconfiguration of the formation to perform different scientific observations would also cause state changes among the network nodes. The application protocol provides for recognition and tracking of the seven states for each node and for protocol changes under specified conditions to adapt the network and satisfy communication requirements associated with the current PFF mission phase. Except during early deployment, when peer-to-peer random access discovery methods would be used, the application protocol provides for operation in a centralized manner.

Reflections on the individual–collective relation in change agency formation in the Samsø renewable energy island project

DEFF Research Database (Denmark)

Carlsson, Monica Susanne

2018-01-01

This paper offers reflections on change agency formation in the Renewable Energy Island (REI) project on Samsø, following a field visit to the island in June 2016. Both individual and collective agency are set out as central for the processes leading to the change in the REI project, spurring ref...

Identification of flap structure-specific endonuclease 1 as a factor involved in long-term memory formation of aversive learning.

Science.gov (United States)

Saavedra-Rodríguez, Lorena; Vázquez, Adrinel; Ortiz-Zuazaga, Humberto G; Chorna, Nataliya E; González, Fernando A; Andrés, Lissette; Rodríguez, Karen; Ramírez, Fernando; Rodríguez, Alan; Peña de Ortiz, Sandra

2009-05-06

We previously proposed that DNA recombination/repair processes play a role in memory formation. Here, we examined the possible role of the fen-1 gene, encoding a flap structure-specific endonuclease, in memory consolidation of conditioned taste aversion (CTA). Quantitative real-time PCR showed that amygdalar fen-1 mRNA induction was associated to the central processing of the illness experience related to CTA and to CTA itself, but not to the central processing resulting from the presentation of a novel flavor. CTA also increased expression of the Fen-1 protein in the amygdala, but not the insular cortex. In addition, double immunofluorescence analyses showed that amygdalar Fen-1 expression is mostly localized within neurons. Importantly, functional studies demonstrated that amygdalar antisense knockdown of fen-1 expression impaired consolidation, but not short-term memory, of CTA. Overall, these studies define the fen-1 endonuclease as a new DNA recombination/repair factor involved in the formation of long-term memories.

Preliminary study of the uranium potential of Tertiary rocks in the central San Juan Basin, New Mexico

International Nuclear Information System (INIS)

Vizcaino, H.P.; O'Neill, A.J.

1977-12-01

Three formations in the Tertiary of the San Juan Basin were investigated for their uranium favorability. They are the Ojo Alamo Sandstone, the Nacimiento Formation, and the San Jose Formation. The study comprised a literature survey and a basin analysis, which consisted of subsurface lithofacies, stratigraphic, and radiometric mapping. Field work in preparation for the subsurface analysis consisted of examination of outcrop and measured sections, surface radiometric traverses, and checking of reported surface radioactive anomalies. Interpretation of subsurface mapping provided the primary basis for favorability assessment. The sandstone trends depicted in lithofacies maps, and stratigraphic cross sections reflect large channel complexes and major fluvial systems originating in favorable source areas. Although surface radioactivity anomalies were found to be few, weak, and widespread, the San Juan Basin has abundant favorable host rocks. The subsurface anomalies, although weak, are widespread and sometimes persist throughout thickness intervals greater than 50 ft. Subsurface anomalies were mapped on a wide-spaced grid and are generalized. On the basis of apparent source, lithology, differential permeability, contents of carbonaceous detritus, and geometry, the Nacimiento Formation and the basal facies of the San Jose Formation in the north-central basin have the greatest potential. The Ojo Alamo Sandstone is less favorable, and the Nacimiento Formation in the southern part of the basin and the upper San Jose Formation are the least favorable of the units studied

CENTRAL REGION COMPONENT1, a Novel Synaptonemal Complex Component, Is Essential for Meiotic Recombination Initiation in Rice[C][W

Science.gov (United States)

Miao, Chunbo; Tang, Ding; Zhang, Honggen; Wang, Mo; Li, Yafei; Tang, Shuzhu; Yu, Hengxiu; Gu, Minghong; Cheng, Zhukuan

2013-01-01

In meiosis, homologous recombination entails programmed DNA double-strand break (DSB) formation and synaptonemal complex (SC) assembly coupled with the DSB repair. Although SCs display extensive structural conservation among species, their components identified are poorly conserved at the sequence level. Here, we identified a novel SC component, designated CENTRAL REGION COMPONENT1 (CRC1), in rice (Oryza sativa). CRC1 colocalizes with ZEP1, the rice SC transverse filament protein, to the central region of SCs in a mutually dependent fashion. Consistent with this colocalization, CRC1 interacts with ZEP1 in yeast two-hybrid assays. CRC1 is orthologous to Saccharomyces cerevisiae pachytene checkpoint2 (Pch2) and Mus musculus THYROID RECEPTOR-INTERACTING PROTEIN13 (TRIP13) and may be a conserved SC component. Additionally, we provide evidence that CRC1 is essential for meiotic DSB formation. CRC1 interacts with HOMOLOGOUS PAIRING ABERRATION IN RICE MEIOSIS1 (PAIR1) in vitro, suggesting that these proteins act as a complex to promote DSB formation. PAIR2, the rice ortholog of budding yeast homolog pairing1, is required for homologous chromosome pairing. We found that CRC1 is also essential for the recruitment of PAIR2 onto meiotic chromosomes. The roles of CRC1 identified here have not been reported for Pch2 or TRIP13. PMID:23943860

Geologic sources and concentrations of selenium in the West-Central Denver Basin, including the Toll Gate Creek watershed, Aurora, Colorado, 2003-2007

Science.gov (United States)

Paschke, Suzanne S.; Walton-Day, Katherine; Beck, Jennifer A.; Webbers, Ank; Dupree, Jean A.

2014-01-01

Toll Gate Creek, in the west-central part of the Denver Basin, is a perennial stream in which concentrations of dissolved selenium have consistently exceeded the Colorado aquatic-life standard of 4.6 micrograms per liter. Recent studies of selenium in Toll Gate Creek identified the Denver lignite zone of the non-marine Cretaceous to Tertiary-aged (Paleocene) Denver Formation underlying the watershed as the geologic source of dissolved selenium to shallow ground-water and surface water. Previous work led to this study by the U.S. Geological Survey, in cooperation with the City of Aurora Utilities Department, which investigated geologic sources of selenium and selenium concentrations in the watershed. This report documents the occurrence of selenium-bearing rocks and groundwater within the Cretaceous- to Tertiary-aged Denver Formation in the west-central part of the Denver Basin, including the Toll Gate Creek watershed. The report presents background information on geochemical processes controlling selenium concentrations in the aquatic environment and possible geologic sources of selenium; the hydrogeologic setting of the watershed; selenium results from groundwater-sampling programs; and chemical analyses of solids samples as evidence that weathering of the Denver Formation is a geologic source of selenium to groundwater and surface water in the west-central part of the Denver Basin, including Toll Gate Creek. Analyses of water samples collected from 61 water-table wells in 2003 and from 19 water-table wells in 2007 indicate dissolved selenium concentrations in groundwater in the west-central Denver Basin frequently exceeded the Colorado aquatic-life standard and in some locations exceeded the primary drinking-water standard of 50 micrograms per liter. The greatest selenium concentrations were associated with oxidized groundwater samples from wells completed in bedrock materials. Selenium analysis of geologic core samples indicates that total selenium

Assessment of groundwater quality of the Tatlicay aquifer and relation to the adjacent evaporitic formations (Cankiri, Turkey).

Science.gov (United States)

Apaydın, Ahmet; Aktaş, Sibel Demirci

2012-04-01

One of the most important hydrogeologic problems in and adjacent areas of evaporitic formations is severe quality degradation of groundwaters. These kinds of groundwaters contain high content of dissolved solids and generally have some limitations for use. Tatlicay basin (north-central Turkey) is an example to effects of the evaporites on groundwater quality in the adjacent alluvium aquifer. Gypsum and anhydrites in the two evaporite formations (Bayindir and Bozkir) effect of the groundwater quality in the alluvium adversely, by dissolution of the evaporites by surface drainage and infiltration into the alluvium aquifer (widespread effect) and by infiltration of low quality gypsum springs (local effect) into the aquifer. Evaporitic formations significantly increased EC, TDS, Ca and SO(4) parameters in the alluvium aquifer in the central and downstream regions. EC has increased roughly from 500-800 to 1,700-2,000 μS/cm, Ca has roughly increased from 3-4 to 10 meq/l, SO(4) has increased 0.5-1 to 11-12 meq/l. Consequently, three clusters were distinguished in the basin; (1) nonevaporitic waters in low TDS, Na, Ca, Mg, Cl and SO(4), (2) diluted waters in high TDS and relatively high Cl, moderate-relatively high Na, Ca, Mg, SO(4), (3) gypsum springs in highest TDS, Ca, SO(4), but moderate Mg and low Na, Cl.

SECURITY THREATS IN CENTRAL ASIA

Directory of Open Access Journals (Sweden)

Çağla Gül Yesevi

2013-07-01

Full Text Available This study will analyze main security threats in Central Asia. It is obvious thatsince the end of Cold War, there have been many security threats in Central Asiaas internal weakness of Central Asian states, terrorism, transnational crime,economic insecurity, environmental issues, drug trafficking, ethnic violence,regional instability. This study will propose thatwith increasing interdependence,states need each other to solve these global security problems. In that sense,regional and sub-regional cooperation between Central Asian states and with otherregional actors has been witnessed. It is clear that the withdrawal of NATO fromAfghanistan will destabilize Central Asia. This study will investigate overallsecurity situation in Central Asia and affects andcontributions of regionalorganizations to Eurasian security

Central nervous insulin resistance: a promising target in the treatment of metabolic and cognitive disorders?

Science.gov (United States)

Hallschmid, M; Schultes, B

2009-11-01

Research on functions and signalling pathways of insulin has traditionally focused on peripheral tissues such as muscle, fat and liver, while the brain was commonly believed to be insensitive to the effects of this hormone secreted by pancreatic beta cells. However, since the discovery some 30 years ago that insulin receptors are ubiquitously found in the central nervous system, an ever-growing research effort has conclusively shown that circulating insulin accesses the brain, which itself does not synthesise insulin, and exerts pivotal functions in central nervous networks. As an adiposity signal reflecting the amount of body fat, insulin provides direct negative feedback to hypothalamic nuclei that control whole-body energy and glucose homeostasis. Moreover, insulin affects distinct cognitive processes, e.g. by triggering the formation of psychological memory contents. Accordingly, metabolic and cognitive disorders such as obesity, type 2 diabetes mellitus and Alzheimer's disease are associated with resistance of central nervous structures to the effects of insulin, which may derive from genetic polymorphisms as well as from long-term exposure to excess amounts of circulating insulin due to peripheral insulin resistance. Thus, overcoming central nervous insulin resistance, e.g. by pharmacological interventions, appears to be an attractive strategy in the treatment and prevention of these disorders. Enhancement of central nervous insulin signalling by administration of intranasal insulin, insulin analogues and insulin sensitisers in basic research approaches has yielded encouraging results that bode well for the successful translation of these effects into future clinical practice.

Satellite formation flying relative dynamics, formation design, fuel optimal maneuvers and formation maintenance

CERN Document Server

Wang, Danwei; Poh, Eng Kee

2017-01-01

This book systematically describes the concepts and principles for multi-satellite relative motion, passive and near passive formation designs, trajectory planning and control for fuel optimal formation maneuvers, and formation flying maintenance control design. As such, it provides a sound foundation for researchers and engineers in this field to develop further theories and pursue their implementations. Though satellite formation flying is widely considered to be a major advance in space technology, there are few systematic treatments of the topic in the literature. Addressing that gap, the book offers a valuable resource for academics, researchers, postgraduate students and practitioners in the field of satellite science and engineering.

STABILITY OF MAGNETIZED DISKS AND IMPLICATIONS FOR PLANET FORMATION

International Nuclear Information System (INIS)

Lizano, Susana; Galli, Daniele; Cai, Mike J.; Adams, Fred C.

2010-01-01

This paper considers gravitational perturbations in geometrically thin disks with rotation curves dominated by a central object, but with substantial contributions from magnetic pressure and tension. The treatment is general, but the application is to the circumstellar disks that arise during the gravitational collapse phase of star formation. We find the dispersion relation for spiral density waves in these generalized disks and derive the stability criterion for axisymmetric (m = 0) disturbances (the analog of the Toomre parameter Q T ) for any radial distribution of the mass-to-flux ratio λ. The magnetic effects work in two opposing directions: on one hand, magnetic tension and pressure stabilize the disk against gravitational collapse and fragmentation; on the other hand, they also lower the rotation rate making the disk more unstable. For disks around young stars the first effect generally dominates, so that magnetic fields allow disks to be stable for higher surface densities and larger total masses. These results indicate that magnetic fields act to suppress the formation of giant planets through gravitational instability. Finally, even if gravitational instability can form a secondary body, it must lose an enormous amount of magnetic flux in order to become a planet; this latter requirement represents an additional constraint for planet formation via gravitational instability and places a lower limit on the electrical resistivity.

Quando instituições federativas fortalecem o governo central?

Directory of Open Access Journals (Sweden)

Marta Arretche

2013-03-01

Full Text Available O artigo refuta o argumento de que o federalismo no Brasil enfraquece a União e favorece minorias sobrerrepresentadas no Congresso, mostrando que a regra de desproporção adotada no Brasil impede o veto da minoria sem que a maioria, por sua vez, tenha recursos para tiranizar a minoria. Além disto, a União tem amplos poderes legislativos, e os partidos inibem tendências inerentemente limitadoras do federalismo. Por fim, não é fato que a aprovação de matérias de interesse federativo exija aprovação em uma multiplicidade de arenas decisórias em que supermaiorias são necessárias. Em conjunto, as instituições do federalismo brasileiro aproximam o Brasil das fórmulas que favorecem a autoridade do governo central.The article examines the proposition that Brazilian federalism is an extreme case of demos-constraining. It demonstrates that the Brazilian federal institutions - the upper chamber veto powers, the broad policy competences of the Union, the partisan parliamentary behavior of senators, the low requirements for plurality formation, and the malapportionement formula - do not constrain the demos. Instead, it favors the central government.

Demographic tensions in Central America.

Science.gov (United States)

1986-08-01

This discussion of Central America focuses on the rapid growth of its population, its stagnating economy, and those countries that are socioeconomically advanced. Between 1950-85 the population of Central America tripled, from 9.1 million to 26. 4 million, due to marked mortality declines and the absence of off-setting fertility declines. The distribution of Central Americas's growing populations sets its population growth apart from that of other developing regions. Currently, almost half of all Central Americans live in cities. Although the average growth rate for Central American countries has fallen and is expected to drop further, the decline does not counterbalance the effect of the absolute rise in population numbers. The average annual growth rate of more than 3% annually in the 1960s fell to about 2.6% in recent years, but this decline is due primarily to socioeconomically advanced Costa Rica and Panama. Central America's age structure further complicates the population crisis. About 43% of Central Americans are under the age of 15. When the increasingly larger young population group enters it reproductive years, the potential for future growth (albeit the falling rate of population increase) is unparalleled. UN population projections show the region's population at 40 million by the year 2000. The 1973 oil crisis began a downward spiral for the buoyant post World War II Central American economy. Between 1950-79, real per capita income growth in Central America doubled, with Central American economies growing an average of 5.3% annually. By the early 1980s, overseas markets of the trade-dependent countries of Central America had dried up due to protectionism abroad and slumping basic commodity prices. These and other factors plunged Central America into its current economic malaise of falling real per capita income, rising unemployment, curtailed export led economic growth, and a rising cost of living. In general, economic growth in Central America

Off-Axis Driven Current Effects on ETB and ITB Formations based on Bifurcation Concept

Science.gov (United States)

Pakdeewanich, J.; Onjun, T.; Chatthong, B.

2017-09-01

This research studies plasma performance in fusion Tokamak system by investigating parameters such as plasma pressure in the presence of an edge transport barrier (ETB) and an internal transport barrier (ITB) as the off-axis driven current position is varied. The plasma is modeled based on the bifurcation concept using a suppression function that can result in formation of transport barriers. In this model, thermal and particle transport equations, including both neoclassical and anomalous effects, are solved simultaneously in slab geometry. The neoclassical coefficients are assumed to be constant while the anomalous coefficients depend on gradients of local pressure and density. The suppression function, depending on flow shear and magnetic shear, is assumed to affect only on the anomalous channel. The flow shear can be calculated from the force balance equation, while the magnetic shear is calculated from the given plasma current. It is found that as the position of driven current peak is moved outwards from the plasma center, the central pressure is increased. But at some point it stars to decline, mostly when the driven current peak has reached the outer half of the plasma. The higher pressure value results from the combination of ETB and ITB formations. The drop in central pressure occurs because ITB stats to disappear.

Investigating the stratigraphy and palaeoenvironments for a suite of newly discovered mid-Cretaceous vertebrate fossil-localities in the Winton Formation, Queensland, Australia

Science.gov (United States)

Tucker, Ryan T.; Roberts, Eric M.; Darlington, Vikie; Salisbury, Steven W.

2017-08-01

The Winton Formation of central Queensland is recognized as a quintessential source of mid-Cretaceous terrestrial faunas and floras in Australia. However, sedimentological investigations linking fossil assemblages and palaeoenvironments across this unit remain limited. The intent of this study was to interpret depositional environments and improve stratigraphic correlations between multiple fossil localities within the preserved Winton Formation in the Eromanga Basin, including Isisford, Lark Quarry, and Bladensburg National Park. Twenty-three facies and six repeated facies associations were documented, indicating a mosaic of marginal marine to inland alluvial depositional environments. These developed synchronously with the final regression of the Eromanga Seaway from central Australia during the late Albian-early Turonian. Investigations of regional- and local-scale structural features and outcrop, core and well analysis were combined with detrital zircon provenance signatures to help correlate stratigraphy and vertebrate faunas across the basin. Significant palaeoenvironmental differences exist between the lower and upper portions of the preserved Winton Formation, warranting informal subdivisions; a lower tidally influenced fluvial-deltaic member and an upper inland alluvial member. This work further demonstrates that the Isisford fauna is part of the lower member of the preserved Winton Formation; whereas, fossil localities around Winton, including Lark Quarry and Bladensburg National Park, are part of the upper member of the Winton Formation. These results permit a more meaningful framework for both regional and global comparisons of the Winton flora and fauna.

UPPER TRIASSIC (NORIAN-RHAETIAN HYPERCALCIFIED SPONGES FROM THE LUT BLOCK, EAST CENTRAL IRAN

Directory of Open Access Journals (Sweden)

FATEMEH AMIRHASSANKHANI

2014-11-01

Full Text Available In order to study the hypercalcified sponges in reefal deposits of the Nayband Formation in Lut Block, the Garm Ab section near the village of Mehran Kushk, located about 20 km northeast of Ferdows city, was sampled. Eight horizons of reefal limestone beds are exposed in this section. The most important reef builders are hypercalcified sponges with some representatives of hexactinellids, scleractinian corals and other reef organisms. The field and lab-observations on rock units, sedimentary facies and faunal assemblages indicate the middle Norian-Rhaetian as the age of the reef horizons. Twenty-three sponge taxa, including 15 of the chambered sphinctozoans, 2 of hexactinellids sponges and 8 non-chambered inozoan were identified. The majority of recognized sponges are reported from the Nayband Formation from the other localities in central Iran. One new species identified as Cryptocoelia maxima n. sp. was recovered and is described here.

Upper Cenozoic deposits of the central Delmarva Peninsula, Maryland and Delaware

Science.gov (United States)

Owens, James Patrick; Denny, Charles Storrow

1979-01-01

The surface and shallow subsurface sediments of the lower Delmarva Peninsula include beds ranging in age from Miocene to Holocene. The oldest beds appear to be typical shelf deposits of the Chesapeake Group (Calvert-Choptank age). These marine units are overlain by deltaic deposits, which range from fluviatile facies in the north (Pensauken Formation) to marginal marine and marine beds in the south ('Yorktown(?) and Cohansey(?)' Formations as used by Rasmussen and Slaughter in 1955). This large deltaic mass underlies most of the Delmarva Peninsula. Fossil age determinations supplemented by some radiometric dates indicate the delta to be largely late Miocene in age. The nonmarine facies of the delta, the Pensauken Formation, previously was considered to be Pleistocene in age. The late Miocene delta and possibly the Yorktown Formation (lower to middle Pliocene) are overlain by a feldspathic sand, the Beaverdam, which is at least in part marginal marine. Microflora recovered from this formation include species no longer indigenous to the Delmarva region ('exotics'). On the basis of existing information, microfloral assemblages containing 'exotics' are pre-Pleistocene in age. The Beaverdam therefore is pre-Pleistocene in age, probably late Pliocene. A highly dissected and weathered unit, the Walston Silt, caps the uplands of the central Delmarva Peninsula, where it overlies the Beaverdam. The Walston has a microflora containing 'exotics' and therefore is considered to be the youngest Tertiary unit (uppermost Pliocene) in this area. Sediments forming a barrier-back-barrier sequence fringe most of the southern Maryland-Delaware part of the Delmarva Peninsula and are found at altitudes of as much as 15 m (50 ft) above sea level. This sequence, the Omar Formation, is Sangamon in age and has been dated radiometrically as 60,000 to about 100,000 years old. The microflora in these beds contains no 'exotics,' and the assemblage suggests a warm-temperate environment. The Omar

The Cold Side of Galaxy Formation: Dense Gas Through Cosmic Time

Science.gov (United States)

Riechers, Dominik A.; ngVLA Galaxy Assembly through Cosmic Time Science Working Group, ngVLA Galaxy Ecosystems Science Working Group

2018-01-01

The processes that lead to the formation and evolution of galaxies throughout the history of the Universe involve the complex interplay between hierarchical merging of dark matter halos, accretion of primordial and recycled gas, transport of gas within galaxy disks, accretion onto central super-massive black holes, and the formation of molecular clouds which subsequently collapse and fragment. The resulting star formation and black hole accretion provide large sources of energy and momentum that light up galaxies and lead to feedback. The ngVLA will be key to further understand how gas is accreted onto galaxies, and the processes that regulate the growth of galaxies through cosmic history. It will reveal how and on which timescales star formation and black hole accretion impact the gas in galaxies, and how the physical properties and chemical state of the gas change as gas cycles between different phases for different galaxy populations over a broad range in redshifts. The ngVLA will have the capability to carry out unbiased, large cosmic volume surveys at virtually any redshift down to an order of magnitude lower gas masses than currently possible in the critical low-level CO lines, thus exposing the evolution of gaseous reservoirs from the earliest epochs to the peak of the cosmic history of star formation. It will also image routinely and systematically the sub-kiloparsec scale distribution and kinematic structure of molecular gas in both normal main-sequence galaxies and large starbursts. The ngVLA thus is poised to revolutionize our understanding of galaxy evolution through cosmic time.

Main Causes Of Mortality Of Companies In Central Region Of Ecuador

Directory of Open Access Journals (Sweden)

Jorge Vladimir Núñez Grijalva

2015-12-01

Full Text Available Most of the studies concerning trading companies, addressing aspects of the initial stage in the life of these, such as its formation stage. However, few studies have examined the final stage of a company and especially the causes of mortality and closing. This article analyzes the main causes of mortality trading companies from three different and complementary disciplines at once: legal, administrative and financial accounting in commercial companies of the Central Region of Ecuador. This research provides a summary of the major causes of mortality, which should be considered by the current and future employers, in order to strengthen their decisions regarding the survival of companies.

Zircon growth in a granitic pluton with specific mechanisms, crystallization temperatures and U-Pb ages. Implication to the 'spatiotemporal' formation process of the Toki granite, central Japan

International Nuclear Information System (INIS)

Yuguchi, Takashi; Ishibashi, Masayuki; Sasao, Eiji; Iwano, Hideki; Danhara, Tohru; Kato, Takenori; Sakata, Shuhei; Hattori, Kentaro; Hirata, Takafumi; Sueoka, Shigeru; Nishiyama, Tadao

2016-01-01

Zircons collected from a granitic pluton provide evidence of serial growth events with specific mechanisms, crystallization temperatures and U-Pb ages, revealing details of the sequential formation process from intrusion through emplacement to crystallization/solidification. The events have been identified by: 1) the study of the internal structure of zircon using cathodoluminescence, 2) deriving crystallization temperatures using Ti-in-zircon thermometry of the internal structure and 3) U-Pb age dating of the internal structure. The magmatic zircons from the Toki granite, central Japan, show two kinds in their internal structure: a low luminescence core (LLC) and oscillatory zonation (OZ). The LLC was produced by interfacial reaction-controlled growth in the granitic magma with cooling from about 910 to 760°C. The formation of OZ occurred by diffusion-controlled growth in a cooling magma chamber from about 850 to 690°C. The U-Pb ages derived from the LLC ranges from 74.7 ± 4.2 to 70.5 ± 1.3 Ma, indicating the incipient intrusion timing of the magma into the shallow crust. The OZ ages distribute from 72.7 ± 0.6 to 70.4 ± 1.7 Ma, which mean the timing from emplacement to crystallization/solidification of the granite pluton. Thus, the serial processes from intrusion through emplacement to crystallization/solidification occurred within a few million years. The old LLC and OZ ages are recognized in the western margins of the Toki granite, implying that the magma forming the western margins was the first to intrude, emplace and crystallize/solidify. The western margins with initial intrusion may accompany the crustal assimilation in order to create sufficient magma reservoir space, which is consistent with larger SrI and ASI values found in the western margins of the granite. (author)

Stratigraphy and Facies of Cretaceous Schrader Bluff and Prince Creek Formations in Colville River Bluffs, North Slope, Alaska

Science.gov (United States)

Flores, Romeo M.; Myers, Mark D.; Houseknecht, David W.; Stricker, Gary D.; Brizzolara, Donald W.; Ryherd, Timothy J.; Takahashi, Kenneth I.

2007-01-01

Stratigraphic and sedimentologic studies of facies of the Upper Cretaceous rocks along the Colville River Bluffs in the west-central North Slope of Alaska identified barrier shoreface deposits consisting of vertically stacked, coarsening-upward parasequences in the Schrader Bluff Formation. This vertical stack of parasequence deposits represents progradational sequences that were affected by shoaling and deepening cycles caused by fluctuations of sea level. Further, the vertical stack may have served to stabilize accumulation of voluminous coal deposits in the Prince Creek Formation, which formed braided, high-sinuosity meandering, anastomosed, and low-sinuosity meandering fluvial channels and related flood plain deposits. The erosional contact at the top of the uppermost coarsening-upward sequence, however, suggests a significant drop of base level (relative sea level) that permitted a semiregional subaerial unconformity to develop at the contact between the Schrader Bluff and Prince Creek Formations. This drop of relative sea level may have been followed by a relative sea-level rise to accommodate coal deposition directly above the unconformity. This rise was followed by a second drop of relative sea level, with formation of incised valley topography as much as 75 ft deep and an equivalent surface of a major marine erosion or mass wasting, or both, either of which can be traced from the Colville River Bluffs basinward to the subsurface in the west-central North Slope. The Prince Creek fluvial deposits represent late Campanian to late Maastrichtian depositional environments that were affected by these base level changes influenced by tectonism, basin subsidence, and sea-level fluctuations.

A reassessment of the in situ formation of close-in super-Earths

OpenAIRE

Ogihara, Masahiro; Morbidelli, Alessandro; Guillot, Tristan

2015-01-01

A large fraction of stars host one or multiple close-in super-Earth planets. There is an active debate about whether these planets formed in situ or at greater distances from the central star and migrated to their current position. It has been shown that part of their observed properties (e.g., eccentricity distribution) can be reproduced by N-body simulations of in situ formation starting with a population of protoplanets of high masses and neglecting the effects of the disk gas. We plan to ...

Europa central

Directory of Open Access Journals (Sweden)

Karel BARTOSEK

2010-02-01

Full Text Available La investigación francesa continúa interesándose por Europa Central. Desde luego, hay límites a este interés en el ambiente general de mi nueva patria: en la ignorancia, producto del largo desinterés de Francia por este espacio después de la Segunda Guerra Mundial, y en el comportamiento y la reflexión de la clase política y de los medios de comunicación (una anécdota para ilustrar este ambiente: durante la preparación de nuestro coloquio «Refugiados e inmigrantes de Europa Central en el movimiento antifascista y la Resistencia en Francia, 1933-1945», celebrado en París en octubre de 1986, el problema de la definición fue planteado concreta y «prácticamente». ¡Y hubo entonces un historiador eminente, para quién Alemania no formaría parte de Europa Central!.

The Central-Western Mediterranean: Anomalous igneous activity in an anomalous collisional tectonic setting

Science.gov (United States)

Lustrino, Michele; Duggen, Svend; Rosenberg, Claudio L.

2011-01-01

The central-western Mediterranean area is a key region for understanding the complex interaction between igneous activity and tectonics. In this review, the specific geochemical character of several 'subduction-related' Cenozoic igneous provinces are described with a view to identifying the processes responsible for the modifications of their sources. Different petrogenetic models are reviewed in the light of competing geological and geodynamic scenarios proposed in the literature. Plutonic rocks occur almost exclusively in the Eocene-Oligocene Periadriatic Province of the Alps while relatively minor plutonic bodies (mostly Miocene in age) crop out in N Morocco, S Spain and N Algeria. Igneous activity is otherwise confined to lava flows and dykes accompanied by relatively greater volumes of pyroclastic (often ignimbritic) products. Overall, the igneous activity spanned a wide temporal range, from middle Eocene (such as the Periadriatic Province) to the present (as in the Neapolitan of southern Italy). The magmatic products are mostly SiO 2-oversaturated, showing calcalkaline to high-K calcalcaline affinity, except in some areas (as in peninsular Italy) where potassic to ultrapotassic compositions prevail. The ultrapotassic magmas (which include leucitites to leucite-phonolites) are dominantly SiO 2-undersaturated, although rare, SiO 2-saturated (i.e., leucite-free lamproites) appear over much of this region, examples being in the Betics (southeast Spain), the northwest Alps, northeast Corsica (France), Tuscany (northwest Italy), southeast Tyrrhenian Sea (Cornacya Seamount) and possibly in the Tell region (northeast Algeria). Excepted for the Alpine case, subduction-related igneous activity is strictly linked to the formation of the Mediterranean Sea. This Sea, at least in its central and western sectors, is made up of several young (fertile vs. refractory mineralogy), the composition of the subducting plate (i.e., the type and amount of sediment cover and the

Central depression in nucleonic densities: Trend analysis in the nuclear density functional theory approach

Science.gov (United States)

Schuetrumpf, B.; Nazarewicz, W.; Reinhard, P.-G.

2017-08-01

Background: The central depression of nucleonic density, i.e., a reduction of density in the nuclear interior, has been attributed to many factors. For instance, bubble structures in superheavy nuclei are believed to be due to the electrostatic repulsion. In light nuclei, the mechanism behind the density reduction in the interior has been discussed in terms of shell effects associated with occupations of s orbits. Purpose: The main objective of this work is to reveal mechanisms behind the formation of central depression in nucleonic densities in light and heavy nuclei. To this end, we introduce several measures of the internal nucleonic density. Through the statistical analysis, we study the information content of these measures with respect to nuclear matter properties. Method: We apply nuclear density functional theory with Skyrme functionals. Using the statistical tools of linear least square regression, we inspect correlations between various measures of central depression and model parameters, including nuclear matter properties. We study bivariate correlations with selected quantities as well as multiple correlations with groups of parameters. Detailed correlation analysis is carried out for 34Si for which a bubble structure has been reported recently, 48Ca, and N =82 , 126, and 184 isotonic chains. Results: We show that the central depression in medium-mass nuclei is very sensitive to shell effects, whereas for superheavy systems it is firmly driven by the electrostatic repulsion. An appreciable semibubble structure in proton density is predicted for 294Og, which is currently the heaviest nucleus known experimentally. Conclusion: Our correlation analysis reveals that the central density indicators in nuclei below 208Pb carry little information on parameters of nuclear matter; they are predominantly driven by shell structure. On the other hand, in the superheavy nuclei there exists a clear relationship between the central nucleonic density and symmetry energy.

Checkpoints to the Brain: Directing Myeloid Cell Migration to the Central Nervous System

Directory of Open Access Journals (Sweden)

Meredith Harrison-Brown

2016-12-01

Full Text Available Myeloid cells are a unique subset of leukocytes with a diverse array of functions within the central nervous system during health and disease. Advances in understanding of the unique properties of these cells have inspired interest in their use as delivery vehicles for therapeutic genes, proteins, and drugs, or as “assistants” in the clean-up of aggregated proteins and other molecules when existing drainage systems are no longer adequate. The trafficking of myeloid cells from the periphery to the central nervous system is subject to complex cellular and molecular controls with several ‘checkpoints’ from the blood to their destination in the brain parenchyma. As important components of the neurovascular unit, the functional state changes associated with lineage heterogeneity of myeloid cells are increasingly recognized as important for disease progression. In this review, we discuss some of the cellular elements associated with formation and function of the neurovascular unit, and present an update on the impact of myeloid cells on central nervous system (CNS diseases in the laboratory and the clinic. We then discuss emerging strategies for harnessing the potential of site-directed myeloid cell homing to the CNS, and identify promising avenues for future research, with particular emphasis on the importance of untangling the functional heterogeneity within existing myeloid subsets.

The Influence of a Precursor Central American Gyre and a Northerly Surge into the Gulf of Tehuantepec on the Formation of Hurricane Patricia in October 2015

Science.gov (United States)

Bosart, L. F.; Bentley, A. M.; Levine, A. S.; Papin, P. P.

2016-12-01

The National Hurricane Center (NHC) initiated advisories on Tropical Depression (TD) Patricia at 1500 UTC 20 October 2015. Patricia originated from a pre-existing area of disturbed weather over the eastern Gulf of Tehuantepec (GoT) subsequent to the formation of a Central American gyre (CAG) and a surge of northerly gap flow across the Isthmus of Tehuantepec (Chivela Pass) and into the GoT. The gap flow was driven by strong low-level height rises over the northern Gulf of Mexico behind a southeastward-moving cold front. Low-level anticyclogenesis over the Gulf of Mexico and the southeastern United States behind the cold front and CAG-related surface pressure falls over Central America contributed to the development of an anomalously strong meridional surface pressure gradient that further sustained the aforementioned gap flow. An elongated strip of cyclonic shear vorticity formed along the eastern margin of the northerly gap flow over the GoT while oceanic heat and moisture fluxes maximized in the core of the strongest flow. Subsequently, this vorticity strip broke down into a cyclonic vortex shortly by 0000 UTC 20 October which prompted the National Hurricane Center to declare that tropical depression (TD) had formed near 13.4°N and 94.0°W by 0600 UTC 20 October. This TD was named tropical storm (TS) Patricia at 0000 UTC 21 October as the developing TS moved over a region of anomalously warm SSTs and high oceanic heat content in the presence of large oceanic heat and moisture fluxes. Northerly gap flow ceased and the CAG circulation broke down as a strengthening TS Patricia in the eastern Pacific crossed the longitude (95°W) of the Chivela Pass, leading to the cessation of northerly gap flow and the onset of strengthening southerly flow. Deep tropical moisture concentrated to the north and east of the now remnant CAG circulation center was advected northwestward into the western Gulf of Mexico where it supported very heavy rainfall in southeastern Texas. This

Predicting galaxy star formation rates via the co-evolution of galaxies and haloes

Science.gov (United States)

Watson, Douglas F.; Hearin, Andrew P.; Berlind, Andreas A.; Becker, Matthew R.; Behroozi, Peter S.; Skibba, Ramin A.; Reyes, Reinabelle; Zentner, Andrew R.; van den Bosch, Frank C.

2015-01-01

In this paper, we test the age matching hypothesis that the star formation rate (SFR) of a galaxy of fixed stellar mass is determined by its dark matter halo formation history, e.g. more quiescent galaxies reside in older haloes. We present new Sloan Digital Sky Survey measurements of the galaxy two-point correlation function and galaxy-galaxy lensing as a function of stellar mass and SFR, separated into quenched and star-forming galaxy samples to test this simple model. We find that our age matching model is in excellent agreement with these new measurements. We also find that our model is able to predict: (1) the relative SFRs of central and satellite galaxies, (2) the SFR dependence of the radial distribution of satellite galaxy populations within galaxy groups, rich groups, and clusters and their surrounding larger scale environments, and (3) the interesting feature that the satellite quenched fraction as a function of projected radial distance from the central galaxy exhibits an ˜r-.15 slope, independent of environment. These accurate predictions are intriguing given that we do not explicitly model satellite-specific processes after infall, and that in our model the virial radius does not mark a special transition region in the evolution of a satellite. The success of the model suggests that present-day galaxy SFR is strongly correlated with halo mass assembly history.

Improved fueling and transport barrier formation with pellet injection from different locations on DIII-D

International Nuclear Information System (INIS)

Baylor, L.R.; Jernigan, T.C.; Gohil, P.

2001-01-01

Pellet injection has been employed on DIII-D from different injection locations to optimize the mass deposition for density profile control and internal transport barrier formation. Transport barriers have been formed deep in the plasma core with central mass deposition from high field side (HFS) injected pellets and in the edge with pellets that trigger L-mode to H-mode transitions. Pellets injected from all locations can trigger the H-mode transition, which depends on the edge density gradient created and not on the radial extent of the pellet deposition. Pellets injected from inside the magnetic axis from the inner wall or vertical port lead to stronger central mass deposition than pellets injected from the low field side (LFS) and thus yield deeper more efficient fueling. (author)

Fragments of deeper parts of the hanging wall mantle preserved as orogenic peridotites in the central belt of the Seve Nappe Complex, Sweden

NARCIS (Netherlands)

Clos, F.; Gilio, M.; van Roermund, H.L.M.

Formation conditions of olivine microstructures are investigated in the Kittelfjäll spinel peridotite (KSP), a fragment of lithospheric mantle which occurs as an isolated body within high grade metamorphic crustal rocks of the Seve Nappe Complex (SNC), southern Västerbotten, central Sweden. The KSP

Pollen spectrum, a cornerstone for tracing the evolution of the eastern Central Asian desert

Science.gov (United States)

Lu, Kai-Qing; Xie, Gan; Li, Min; Li, Jin-Feng; Trivedi, Anjali; Ferguson, David K.; Yao, Yi-Feng; Wang, Yu-Fei

2018-04-01

The temperate desert in arid Central Asia (ACA) has acted as a thoroughfare for the ancient Silk Road and today's Belt and Road, linking economic and cultural exchanges between East and West. The interaction between human sustainable development and the dynamic change in the desert ecosystem in this region is an area of concern for governments and scientific communities. Nevertheless, the lack of a pollen spectrum of the dominant taxa within the temperate desert vegetation and a corresponding relation between pollen assemblages and specific desert vegetation types is an obstacle to further understanding the formation and maintenance of this desert ecosystem. In this work, we link pollen assemblages to specific desert vegetation types with a new pollen spectrum with specific pollen grains, specific plant taxa and related habitats, providing a solid foundation for further tracing the evolution of the desert ecosystem in eastern arid Central Asia.

Neoliberal Forms of Capital and The Rise of Social Movement Partyism in Central America

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Paul Almeida

2015-08-01

Full Text Available Historical shifts in global economic formations shape the strategies of resistance movements in the global South. Neoliberal forms of economic development over the past thirty years in Central America have weakened traditional actors sponsoring popular mobilization such as labor unions and rural cooperatives. At the same time, the free market reforms produced new threats to economic livelihood and well-being throughout the region. The neoliberal measures that have generated the greatest levels of mass discontent include rising prices, privatization, labor flexibility laws, mining projects, and free trade. This article analyzes the role of emerging anti-neoliberal political parties in alliance with popular movements in Central America. Countries with already existing strong anti-systemic parties in the initial phases of the global turn to neoliberalism in the late twentieth century resulted in more efficacious manifestations of social movement partyism in the twenty-first century resisting free market globalization.

Portals in Higher and Further Education. EDNER (Formative Evaluation of the Distributed National Electronic Resource) Project. Issues Paper.

Science.gov (United States)

Manchester Metropolitan Univ. (England).

This issues paper, fifth in a series of eight, is intended to distill formative evaluation questions on topics that are central to the development of the higher and further education information environment in the United Kingdom. The term "portal" is so widely used by so many people with so many different perspectives that definition is…

Cross-regulation by CrcZ RNA controls anoxic biofilm formation in Pseudomonas aeruginosa

Science.gov (United States)

Pusic, Petra; Tata, Muralidhar; Wolfinger, Michael T.; Sonnleitner, Elisabeth; Häussler, Susanne; Bläsi, Udo

2016-12-01

Pseudomonas aeruginosa (PA) can thrive in anaerobic biofilms in the lungs of cystic fibrosis (CF) patients. Here, we show that CrcZ is the most abundant PA14 RNA bound to the global regulator Hfq in anoxic biofilms grown in cystic fibrosis sputum medium. Hfq was crucial for anoxic biofilm formation. This observation complied with an RNAseq based transcriptome analysis and follow up studies that implicated Hfq in regulation of a central step preceding denitrification. CrcZ is known to act as a decoy that sequesters Hfq during relief of carbon catabolite repression, which in turn alleviates Hfq-mediated translational repression of catabolic genes. We therefore inferred that CrcZ indirectly impacts on biofilm formation by competing for Hfq. This hypothesis was supported by the findings that over-production of CrcZ mirrored the biofilm phenotype of the hfq deletion mutant, and that deletion of the crcZ gene augmented biofilm formation. To our knowledge, this is the first example where competition for Hfq by CrcZ cross-regulates an Hfq-dependent physiological process unrelated to carbon metabolism.

Increase in peripheral oxidative stress during hypercholesterolemia is not reflected in the central nervous system: evidence from two mouse models.

Science.gov (United States)

Ding, Tao; Yao, Yeumang; Praticò, Domenico

2005-05-01

In recent years oxidative stress has been widely implicated as a pathogenetic mechanism of several diseases, and a variety of indices and assays have been developed to assess this phenomenon in complex biological systems. Most of these biomarkers can be measured virtually in every biological fluid and tissue, providing us with the opportunity to assess their formation at local site of oxidative injury. However, despite their widespread use, it is still not completely clear how their peripheral formation correlates with the levels measured in the central nervous system. For this reason, we utilized two well-characterized animal models of chronic peripheral oxidative stress, low-density lipoprotein receptor (LDLR)-deficient and C57BL/6 mice on a high fat diet. After 8 weeks on the diet, we assessed isoprostane, marker of lipid peroxidation, and carbonyls, marker of protein oxidation, in several organs of these animals. Compared with animals on chow, mice on the high fat diet showed a significant increase in both biomarkers in plasma, heart, aorta and liver but not in brain tissues. This observation was confirmed by the selective accumulation of radioactivity in the peripheral organs but not in the brains of mice injected with tritiated isoprostane. Our findings indicate that in hypercholesterolemia the peripheral formation of oxidative products does not contribute to their levels found in the central nervous system.

Towards a dynamical description of intermediate mass fragment formation in heavy-ion collisions at some tens of MeV/A

International Nuclear Information System (INIS)

Suraud, E.

1990-01-01

We briefly remind the possible dynamical scenario of fragments formation in central heavy-ion collisions at some tens of MeV/A. We discuss how present day dynamical models can describe fragment formation. We show that particle methods provide a reasonable solution of Boltzman-like equations. We next turn to the Boltzmann-Langevin formalism which gives a well defined framework for the understanding of Intermediate Mass Fragments formation. We present a first numerical solution of this equation and show the importance of fluctuations in the dynamics of the collision. We finally apply the formalism to the onset of multifragmentation in the 40 Ca + 40 Ca system between 20 and 60 MeV/A beam energy

Geologic Reconnaissance of the Antelope-Ashwood Area, North-Central Oregon: With Emphasis on the John Day Formation of Late Oligocene and Early Miocene Age

Science.gov (United States)

Peck, Dallas L.

1964-01-01

This report briefly describes the geology of an area of about 750 square miles in Jefferson, Wasco, Crook, and Wheeler Counties, Oregon. About 16,000 feet of strata that range in age from pre-Tertiary to Quaternary are exposed. These include the following units: pre-Tertiary slate, graywacke, conglomerate, and meta-andesite; Clarno Formation of Eocene age - lava flows, volcanic breccia, tuff, and tuffaceous mudstone, chiefly of andesitic composition; John Day Formation of late Oligocene and early Miocene age - pyroclastic rocks, flows, and domes, chiefly of rhyolitic composition; Columbia River Basalt of middle Miocene age - thick, columnar jointed flows of very fine grained dense dark-gray basalt; Dalles Formation of Pliocene age - bedded tuffaceous sandstone, siltstone, and conglomerate; basalt of Pliocene or Pleistocene age - lava flows of porous-textured olivine basalt; and Quaternary loess, landslide debris, and alluvium. Unconformities separate pre-Tertiary rocks and Clarno Formation, Clarno and John Day Formations, John Day Formation and Columbia River Basalt, and Columbia River Basalt and Dalles Formation. The John Day Formation, the only unit studied in detail, consists of about 4,000 feet of tuff, lapilli tuff, strongly to weakly welded rhyolite ash flows, and less abundant trachyandesite flows and rhyolite flows and domes. The formation was divided into nine mappable members in part of the area, primarily on the basis of distinctive ledge-forming welded ash-flow sheets. Most of the sheets are composed of stony rhyolite containing abundant lithophysae and sparse phenocrysts. One sheet contains 10 to 20 percent phenocrysts, mostly cryptoperthitic soda sanidine, but including less abundant quartz, myrmekitic intergrowths of quartz and sanidine, and oligoclase. The rhyolitic ash flows and lava flows were extruded from nearby vents, in contrast to some of the interbedded air-fall tuff and lapilli tuff of dacitic and andesitic composition that may have been

Implications of ammonia emissions for fine aerosol formation and visibility impairment. A case study from the Lower Fraser Valley, British Columbia

DEFF Research Database (Denmark)

Barthelmie, R.J.; Pryor, S.C.

1998-01-01

of nitrogen and sulphur oxides over agricultural areas in the eastern and central valley with higher ammonia emissions favours subsequent ammonium nitrate and sulphate formation. This leads to higher fine mass concentrations and lowest visibility in the predominantly agricultural regions of the valley. (C...

Tertiary Lymphoid Organs in Central Nervous System Autoimmunity

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Meike Mitsdoerffer

2016-10-01

Full Text Available Multiple sclerosis (MS is an autoimmune disease characterized by chronic inflammation in the central nervous system (CNS, which results in permanent neuronal damage and substantial disability in patients. Autoreactive T cells are important drivers of the disease, however, the efficacy of B cell depleting therapies uncovered an essential role for B cells in disease pathogenesis. They can contribute to inflammatory processes via presentation of autoantigen, secretion of pro-inflammatory cytokines and production of pathogenic antibodies. Recently, B cell aggregates reminiscent of tertiary lymphoid organs (TLOs were discovered in the meninges of MS patients, leading to the hypothesis that differentiation and maturation of autopathogenic B and T cells may partly occur inside the CNS. Since these structures were associated with a more severe disease course, it is extremely important to gain insight into the mechanism of induction, their precise function and clinical significance. Mechanistic studies in patiens are limited. However, a few studies in the MS animal model experimental autoimmune encephalomyelitis (EAE recapitulate TLO formation in the CNS and provide new insight into CNS TLO features, formation and function. This review summarizes what we know so far about CNS TLOs in MS and what we have learned about them from EAE models. It also highlights the areas that are in need of further experimental work, as we are just beginning to understand and evaluate the phenomenon of CNS TLOs.

Network centrality based team formation: A case study on T-20 cricket

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Paramita Dey

2017-07-01

Full Text Available This paper proposes and evaluates the novel utilization of small world network properties for the formation of team of players with both best performances and best belongingness within the team network. To verify this concept, this methodology is applied to T-20 cricket teams. The players are treated as nodes of the network, whereas the number of interactions between team members is denoted as the edges between those nodes. All intra country networks form the cricket network for this case study. Analysis of the networks depicts that T-20 cricket network inherits all characteristics of small world network. Making a quantitative measure for an individual performance in the team sports is important with respect to the fact that for team selection of an International match, from pool of best players, only eleven players can be selected for the team. The statistical record of each player considered as a traditional way of quantifying the performance of a player. But the other criteria such as performing against a strong opponent or performance as an effective team member such as fielding, running between the wickets, good partnership deserves more credential. In this paper a revised method based on social networking is presented to quantify the quality of team belongingness and efficiency of each player. The application of Social Network Analysis (SNA is explored to measure performances and the rank of the players. A bidirectional weighted network of players is generated using the information collected from T-20 cricket (2014–2016 and used for network analysis. Thus team was formed based on that ranking and compared with their IPL (Indian Premier League performances of 2016.

Central Banking after the Crisis

OpenAIRE

Frederick S. Mishkin

2013-01-01

This paper explores where central banking is heading after the recent financial crisis. First it discusses the central bank consensus before the crisis and then outlines the key facts learned from the crisis that require changes in the way central banks conduct their business. Finally, it discusses four main areas in which central banks are altering their policy frameworks: 1) the interaction between monetary and financial stability policies, 2) nonconventional monetary policy, 3) risk manage...

Central ignition scenarios for TFTR

International Nuclear Information System (INIS)

Zweben, S.J.; Redi, M.H.; Bateman, G.

1986-03-01

The possibility of obtaining ignition in TFTR by means of very centrally peaked density profiles is examined. It is shown that local central alpha heating can be made to exceed local central energy losses (''central ignition'') under global conditions for which Q greater than or equal to 1. Time dependent 1-D transport simulations show that the normal global ignition requirements are substantially relaxed for plasmas with peaked density profiles. 18 refs., 18 figs

Organization of central synapses by adhesion molecules.

Science.gov (United States)

Tallafuss, Alexandra; Constable, John R L; Washbourne, Philip

2010-07-01

Synapses are the primary means for transmitting information from one neuron to the next. They are formed during the development of the nervous system, and the formation of appropriate synapses is crucial for the establishment of neuronal circuits that underlie behavior and cognition. Understanding how synapses form and are maintained will allow us to address developmental disorders such as autism, mental retardation and possibly also psychological disorders. A number of biochemical and proteomic studies have revealed a diverse and vast assortment of molecules that are present at the synapse. It is now important to untangle this large array of proteins and determine how it assembles into a functioning unit. Here we focus on recent reports describing how synaptic cell adhesion molecules interact with and organize the presynaptic and postsynaptic specializations of both excitatory and inhibitory central synapses. © The Authors (2010). Journal Compilation © Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

The Sedimentary History of Southern Central Crete: Implications for Neogene Uplift

Science.gov (United States)

Kröger, K.; Brachert, T. C.; Reuter, M.

2003-04-01

The tectonic setting of Crete was largely extensional since Lower Miocene uplift and exhumation of HP/LT rocks. Erosion of uplifted areas resulted in the deposition of terrestrial to marine sediments in the Messara and Iraclion Basins. There are several concurring models that discuss Late Neogene uplift of the basinal margins. Neogene near shore sediments in the south of the Messara Basin record fault movements contemporaneous to sedimentation and sedimentary input from the hinterland. Therefore they provide information on the paleogeographic situation and the resulting amount of subsidence and uplift of mountain areas since the Upper Miocene. The studied sediments consist of terrestrial to shallow marine, floodplain related sediments of the Upper Miocene Ambelouzos Formation that are overlain by platform limestones of the Upper Miocene Varvara Formation. In the Messara Basin these units are overlain by the Pliocene Kourtes Formation. The stratigraphic architecture of these deposits indicates fragmentation of the basinal margin. Proximal boulder conglomerates and reworked blocks of the Ambelouzos formation indicate fault activity during the deposition of the Varvara Formation. Contents of terrigenous clastics, provided by rivers and distributed by longshore currents, are high in the Ambelouzos and the lower Varvara Formations but decrease rapidly upsection within the Varvara Formation. This indicates drowning of the fault bounded blocks and little topography of the hinterland (Asteroussia Mountains) at that time. The Pliocene marls at the southern margin of the Messara Basin contain lithoclasts of the Upper Miocene limestones and thus indicate uplift of the carbonate platform. The modern topographic elevation of formerly drowned fault bounded blocks requires a minimum uplift of 400m. Main uplift occurred at approximately orthogonal NW-SE and SW-NE striking normal to oblique faults. The present elevation of the Asteroussia Mountains indicates net uplift of at least

A dϕ-Strategy: Facilitating Dual-Formation Control of a Virtually Connected Team

Directory of Open Access Journals (Sweden)

Bibhya Sharma

2017-01-01

Full Text Available This paper describes the design of new centralized acceleration-based controllers for the multitask problem of motion planning and control of a coordinated lead-carrier team fixed in a dual-formation within an obstacle-ridden environment. A dϕ-strategy, where d and ϕ are Euclidean measures with respect to the lead robot, is developed to ensure virtual connectivity of the carrier robots to the lead robot. This connectivity, built into the system itself, inherently ensures globally rigid formation between each lead-carrier pair of the team. Moreover, a combination of target configuration, dϕ-strategy, orientation consensus, and avoidance of end-effector of robots results in a second, locally rigid formation (not infinitesimally rigid. Therefore, for the first time, a dual-formation control problem of a lead-carrier team of mobile manipulators is considered. This and other kinodynamic constraints have been treated simultaneously via the overarching Lyapunov-based control scheme, essentially a potential field method favored in the field of robotics. The formulation of this new scheme, demonstrated effectively via computer simulations, is timely, given that the current proposed engineering solutions, allowing autonomous vehicles on public roads, include the development of special lanes imbued with special sensors and wireless technologies.

Detection of central circuits implicated in the formation of novel pain memories

Directory of Open Access Journals (Sweden)

Upadhyay J

2016-09-01

Full Text Available Jaymin Upadhyay,1 Julia Granitzka,1 Thomas Bauermann,2 Ulf Baumgärtner,3 Markus Breimhorst,1 Rolf-Detlef Treede,3 Frank Birklein1 1Department of Neurology, 2Department of Neuroradiology, University Medical Centre, Johannes Gutenberg University Mainz, Mainz, 3Department of Neurophysiology, Center for Biomedicine and Medical Technology Mannheim (CBTM, Heidelberg University, Mannheim, Germany Abstract: Being able to remember physically and emotionally painful events in one’s own past may shape behavior, and can create an aversion to a variety of situations. Pain imagination is a related process that may include recall of past experiences, in addition to production of sensory and emotional percepts without external stimuli. This study aimed to understand 1 the central nervous system processes that underlie pain imagination, 2 the retrieval of pain memories, and 3 to compare the latter with visual object memory. These goals were achieved by longitudinally investigating brain function with functional magnetic resonance imaging in a unique group of healthy volunteers who had never experienced tooth pain. In these subjects, we compared brain responses elicited during three experimental conditions in the following order: imagination of tooth pain (pain imagination, remembering one’s own house (object memory, and remembrance of tooth pain following an episode of induced acute tooth pain (pain memory. Key observations stemming from group-level conjunction analyses revealed common activation in the posterior parietal cortex for both pain imagination and pain memory, while object and pain memory each had strong activation predominantly within the middle frontal gyrus. When contrasting pain imagination and memory, significant activation differences were observed in subcortical structures (ie, parahippocampus – pain imagination > pain memory; midbrain – pain memory > pain imagination. Importantly, these findings were observed in the presence of

THE TWO CENTRAL STARS OF NGC 1514: CAN THEY ACTUALLY BE RELATED?

Energy Technology Data Exchange (ETDEWEB)

Méndez, Roberto H.; Kudritzki, Rolf-Peter [Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Urbaneja, Miguel A., E-mail: mendez@ifa.hawaii.edu [Institut für Astro- und Teilchenphysik, Universität Innsbruck, Technikerstr. 25/8, A-6020 Innsbruck (Austria)

2016-10-01

The central star of the planetary nebula NGC 1514 is among the visually brightest central stars in the sky ( V = 9.5). It has long been known to show a composite spectrum, consisting of an A-type star and a much hotter star responsible for the ionization of the surrounding nebula. These two stars have always been assumed to form a binary system. High-resolution spectrograms obtained with Espadons at the Canada–France–Hawaii Telescope on Maunakea have allowed us to measure good radial velocities for both stars: they differ by 13 ± 2 km s{sup −1}. The stellar velocities were unchanged after 500 days. We have also estimated the metallicity of the cooler star. Combining these data with other information available in the literature, we conclude that, unless all the published nebular radial velocities are systematically wrong, the cooler star is just a chance alignment, and the two stars are not orbiting each other. The cooler star cannot have played any role in the formation of NGC 1514.

Phenology and Growth dynamics of Avicennia marina in the Central Red Sea

KAUST Repository

Almahasheer, Hanan

2016-11-28

The formation of nodes, stem elongation and the phenology of stunted Avicennia marina was examined in the Central Red Sea, where Avicennia marina is at the limit of its distribution range and submitted to extremely arid conditions with salinity above 38 psu and water temperature as high as 35° C. The annual node production was rather uniform among locations averaging 9.59 node y−1, which resulted in a plastocron interval, the interval in between production of two consecutive nodes along a stem, of 38 days. However, the internodal length varied significantly between locations, resulting in growth differences possibly reflecting the environmental conditions of locations. The reproductive cycle lasted for approximately 12 months, and was characterized by peak flowering and propagule development in November and January. These phenological observations provide a starting point for research and restoration programs on the ecology of mangroves in the Central Red Sea, while the plastochrone index reported here would allow calculations of the growth and production of the species from simple morphological measurements.

Phenology and Growth dynamics of Avicennia marina in the Central Red Sea

Science.gov (United States)

Almahasheer, Hanan; Duarte, Carlos M.; Irigoien, Xabier

2016-01-01

The formation of nodes, stem elongation and the phenology of stunted Avicennia marina was examined in the Central Red Sea, where Avicennia marina is at the limit of its distribution range and submitted to extremely arid conditions with salinity above 38 psu and water temperature as high as 35° C. The annual node production was rather uniform among locations averaging 9.59 node y−1, which resulted in a plastocron interval, the interval in between production of two consecutive nodes along a stem, of 38 days. However, the internodal length varied significantly between locations, resulting in growth differences possibly reflecting the environmental conditions of locations. The reproductive cycle lasted for approximately 12 months, and was characterized by peak flowering and propagule development in November and January. These phenological observations provide a starting point for research and restoration programs on the ecology of mangroves in the Central Red Sea, while the plastochrone index reported here would allow calculations of the growth and production of the species from simple morphological measurements. PMID:27892956

Drilling and geophysical logs of the tophole at an oil-and-gas well site, Central Venango County, Pennsylvania

Science.gov (United States)

Williams, John H.; Bird, Philip H.; Conger, Randall W.; Anderson, J. Alton

2014-01-01

In a study conducted by the U.S. Geological Survey, in cooperation with the Pennsylvania Department of Conservation and Natural Resources, Bureau of Topographic and Geologic Survey, drilling and geophysical logs were used to characterize the geohydrologic framework and the freshwater and saline-water zones penetrated by the tophole at an oil-and-gas well site in central Venango County, Pennsylvania. The geohydrologic setting of the well site is typical of the dissected Appalachian Plateau underlain by Pennsylvanian and Mississippian sandstone and shale. The drilling, gamma, and acoustic-televiewer logs collected from the 575-foot deep tophole define the penetrated Pennsylvanian and Mississippian stratigraphic units and their lithology. The caliper, video, and acoustic-televiewer logs delineate multiple bedding-related and high-angle fractures in the lower Pottsville Group and Shenango Formation from 22 to 249 feet below land surface. The caliper and acoustic-televiewer logs indicate a sparsity of fractures below 249 feet below land surface in the lowermost Shenango Formation, Cuyahoga Group, Corry Sandstone, “Drake Well” formation, and upper Riceville Formation.

Political and Legal Bases of Foreign Policy Activity of the European Union in the Region of Central Asia

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Turdimurat M. Tursunmuratov

2017-10-01

Full Text Available The author analyses the European Union’s foreign policy in Central Asia. He indicates the basic tendencies of development of the EU cooperation with the countries of Central Asian region. Further, the author analyzes the implementation of joint projects within the framework adopted by the Partnership Agreements. Based on a critical analysis, the researcher highlights a number of constraints to effective development of relations between the EU and Central Asian states. He carries out a structural analysis of conceptual documents of the European Union for the development of bilateral and multilateral relations with Central Asian countries in the region. Scientific novelty of this work lies in the systematization of stages in the evolution of relations between the European Union and the countries of Central Asia. The author divides the formation of cooperation into four main stages. The first stage of the relations between the EU and the countries of Central Asia includes conceptual framework of the legal regulatory structure of bilateral and multilateral cooperation. The second stage is characterized by the realization of a number of joint projects in the field of transport communications, democratic transformations, regional security and stability. The third stage of the relations is determined by acquiring of special geographical significance of the region of Central Asia resulting from the engagement of the International Security Assistance Force in Afghanistan in 2001. The fourth stage has begun in 2015 with the adoption of the EU Strategy for a New Partnership with Central Asia for 2017-2021. These studies serve as a basis for developing some important proposals and recommendations for the improvement of the effectiveness of cooperation between the parties.

3D gadolinium-enhanced MRI venography: Evaluation of central chest veins and impact on patient management

International Nuclear Information System (INIS)

Oxtoby, J.W.; Widjaja, E.; Gibson, K.M.; Uzoka, K.

2001-01-01

AIM: To assess the value of a simplified 3D gadolinium-enhanced magnetic resonance imaging (MRI) venography for central chest veins. MATERIALS AND METHODS: In this retrospective study of 24 patients, the MRI findings and medical records were reviewed to determine whether MRI results correlated with subsequent findings, and to determine the effect on clinical management. 3D steady state gradient-echo sequence, fast imaging with steady state precession (FISP), was used. We employed a simplified protocol not requiring bolus timing or subtraction to achieve rapid data acquisition and hence good compliance in this group of frail patients. Following intravenous administration of a bolus of gadolinium, two acquisitions were obtained in order to ensure adequate opacification of all veins. Individual partitions and maximum intensity projections were then analysed to determine whether the veins were patent, stenosed or occluded. RESULTS: The indications for MRI were to assess the patency of central veins for the purpose of cannulation or arteriovenous fistula formation in 17 patients. Out of the 12 patients who proceeded to an intervention, MRI venography successfully predicted an appropriate site in 10 patients. In the remaining seven patients, MRI venography was valuable in confirming or excluding the clinical suspicion of central venous thrombosis and directly influenced the management in five patients. CONCLUSION: 3D gadolinium-enhanced MRI venography is a valuable means of providing a global representation of the central venous system and guiding subsequent central venous cannulation. Oxtoby, J.W. et al. (2001)

Why adult formation

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Andrej Justinek

1997-01-01

Full Text Available The article argues that the primary aim of adult formation is comprehensive personality development which is supposed to ensure quality existence in modern world. The article also suggests that formarion is a permanent process. Justinek puts special emphasis on adult formation methodology and defines fundamental formation styles which encourage independent action in individuals. Justinek differentiates between formation and education. methods and concludes that formation methods are related to the emotional sphere of personality, and education methods mostly to the rational. Justinek believes that formation of adults is based primarily on appropriate formation methodology.

A glutathione conjugate of hepoxilin A3: Formation and action in the rat central nervous system

International Nuclear Information System (INIS)

Pace-Asciak, C.R.; Laneuville, O.; Su, W.G.; Corey, E.J.; Gurevich, N.; Wu, P.; Carlen, P.L.

1990-01-01

Incubation of (8R)- and (8S)-[1-14C]hepoxilin A3 [where hepoxilin A3 is 8-hydroxy-11,12-epoxyeicosa-(5Z,9E,14Z)-trienoic acid] and glutathione with homogenates of rat brain hippocampus resulted in a product that was identified as the (8R) and (8S) diastereomers of 11-glutathionyl hepoxilin A3 by reversed-phase high performance liquid chromatographic comparison with the authentic standard made by total synthesis. Identity was further confirmed by cleavage of the isolated product with gamma-glutamyltranspeptidase to yield the corresponding cysteinylglycinyl conjugate that was identical by reversed-phase high performance liquid chromatographic analysis with the enzymic cleavage product derived from the synthetic glutathionyl conjugate. The glutathionyl and cysteinylglycinyl conjugate are referred to as hepoxilin A3-C and hepoxilin A3-D, respectively, by analogy with the established leukotriene nomenclature. Formation of hepoxilin A3-C was greatly enhanced with a concomitant decrease in formation of the epoxide hydrolase product, trioxilin A3, when the epoxide hydrolase inhibitor trichloropropene oxide was added to the incubation mixture demonstrating the presence of a dual metabolic pathway in this tissue involving hepoxilin epoxide hydrolase and glutathione S-transferase processes. Hepoxilin A3-C was tested using intracellular electrophysiological techniques on hippocampal CA1 neurons and found to be active at concentrations as low as 16 nM in causing membrane hyperpolarization, enhanced amplitude and duration of the post-spike train afterhyperpolarization, a marked increase in the inhibitory postsynaptic potential, and a decrease in the spike threshold. These findings suggest that these products in the hepoxilin pathway of arachidonic acid metabolism formed by the rat brain may function as neuromodulators

The Impact of Biofilm Formation on the Persistence of Candidemia

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Wei-Sin Li

2018-06-01

Full Text Available This study aimed to determine the predictors of persistent candidemia and examine the impact of biofilm formation by Candida isolates in adult patients with candidemia. Of the adult patients with candidemia in Kaohsiung Chang Gung Memorial Hospital between January 2007 and December 2012, 68 case patients with persistent candidemia (repeated candidemia after a 3-day systemic antifungal therapy and 68 control patients with non-persistent candidemia (Candida clearance from the bloodstream after a 3-day systemic antifungal therapy were included based on propensity score matching and matching for the Candida species isolated. Biofilm formation by the Candida species was assessed in vitro using standard biomass assays. Presence of central venous catheters (CVCs at diagnosis (adjusted odd ratio [AOR], 3.77; 95% confidence interval [CI], 1.09–13.00, p = 0.04, infection with higher biofilm forming strains of Candida species (AOR, 8.03; 95% CI, 2.50–25.81; p < 0.01, and receipt of suboptimal fluconazole doses as initial therapy (AOR, 5.54; 95% CI, 1.53–20.10; p < 0.01 were independently associated with persistent candidemia. Biofilm formation by Candida albicans, C. tropicalis, and C. glabrata strains was significantly higher in the case patients than in the controls. There were no significant differences in the overall mortality and duration of hospitalization between the two groups. Our data suggest that, other than presence of retained CVCs and use of suboptimal doses of fluconazole, biofilm formation was highly associated with development of persistent candidemia.

Philosophy teaching and the constitution of personal identity: Formation, autonomy and gender

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Tânia Aparecida Kuhnen

2017-12-01

Full Text Available This article investigates the contribution of philosophy in basic education classes for the formation of the students as individuals, helping them in the process of identity construction. Philosophy teaching in high school contributes to constituteself-aware individuals in space and time. It helps them with the ability to reflect critically on the social context in which they are inserted and on the expectations in terms of fixed gender roles imposed from the outside in. In this sense, the particularity of philosophical knowledge, as critical thinking through the creation of concepts, entails a more authentic and autonomous individual formation. This also justifies the presence of philosophy as a subject in high school. The personal gender experience is central in the formation of identity. So it is important to discuss this topic with the students. Due to that, we advocate the importance of bringing gender issues to philosophy classes. It refers a real experience that can be problematized in order to deconstruct naturalized gender performativity and think about the inequalities that pervade this social category. Thus, students can constitute a more conscious individual identity, critical to social position that their genders occupy in the social environment.

Examining the central and peripheral processes of written word production through meta-analysis

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Jeremy ePurcell

2011-10-01

Full Text Available Producing written words requires central cognitive processes (such as orthographic long-term and working memory as well as more peripheral processes responsible for generating the motor actions needed for producing written words in a variety of formats (handwriting, typing, etc.. In recent years, various functional neuroimaging studies have examined the neural substrates underlying the central and peripheral processes of written word production. This study provides the first quantitative meta-analysis of these studies by applying Activation Likelihood Estimation methods (Turkeltaub et al., 2002. For alphabet languages, we identified 11 studies (with a total of 17 experimental contrasts that had been designed to isolate central and/or peripheral processes of word spelling (total number of participants = 146. Three ALE meta-analyses were carried out. One involved the complete set of 17 contrasts; two others were applied to subsets of contrasts to distinguish the neural substrates of central from peripheral processes. These analyses identified a network of brain regions reliably associated with the central and peripheral processes of word spelling. Among the many significant results, is the finding that the regions with the greatest correspondence across studies were in the left inferior temporal/fusiform gyri and left inferior frontal gyrus. Furthermore, although the angular gyrus has traditionally been identified as a key site within the written word production network, none of the meta-analyses found it to be a consistent site of activation, identifying instead a region just superior/medial to the left angular gyrus in the left posterior intraparietal sulcus. In general these meta-analyses and the discussion of results provide a valuable foundation upon which future studies that examine the neural basis of written word production can build.

Thallium isotope variations in an ore-bearing continental igneous setting: Collahuasi Formation, northern Chile

Science.gov (United States)

Baker, R. G. A.; Rehkämper, M.; Ihlenfeld, C.; Oates, C. J.; Coggon, R.

2010-08-01

Thallium is a highly incompatible element and a large fraction of the bulk silicate Earth Tl budget is, therefore, expected to reside in the continental crust. Nonetheless, the Tl isotope systematics of continental rocks are essentially unexplored at present. Here, we present new Tl isotope composition and concentration data for a suite of 36 intrusive and extrusive igneous rocks from the vicinity of porphyry Cu deposits in the Collahuasi Formation of the Central Andes in northern Chile. The igneous lithologies of the rocks are variably affected by the hydrothermal alteration that accompanied the formation of the Cu deposits. The samples display Tl concentrations that vary by more than an order of magnitude, from 0.1 to 3.2 μg/g, whilst ɛ 205Tl ranges between -5.1 and +0.1 (ɛ 205Tl is the deviation of the 205Tl/ 203Tl isotope ratio of a sample from a standard in parts per 10 4). These variations are primarily thought to be a consequence of hydrothermal alteration processes, including metasomatic transport of Tl, and formation/breakdown of Tl-bearing minerals, which are associated with small but significant Tl isotope effects. The Tl abundances show excellent correlations with both K and Rb concentrations but no co-variation with Cu. This demonstrates that Tl displays only limited chalcophile affinity in the continental crust of the Collahuasi Formation, but behaves as a lithophile element with a distribution that is primarily governed by partitioning of Tl + into K +-bearing phases. Collahuasi samples with propylitic alteration features, which are derived from the marginal parts of the hydrothermal systems, have, on average, slightly lighter Tl isotope compositions than rocks from the more central sericitic and argillic alteration zones. This small but statistically significant difference most likely reflects preferential retention of isotopically heavy Tl in alteration phases, such as white micas and clays, which formed during sericitic and argillic alteration.

Sequential development of platform to off-platform facies of the great American carbonate bank in the central Appalachians: chapter 15

Science.gov (United States)

Brezinski, David K.; Taylor, John F.; Repetski, John E.

2012-01-01

In the central Appalachians, carbonate deposition of the great American carbonate bank began during the Early Cambrian with the creation of initial ramp facies of the Vintage Formation and lower members of the Tomstown Formation. Vertical stacking of bioturbated subtidal ramp deposits (Bolivar Heights Member) and dolomitized microbial boundtsone (Fort Duncan Member) preceded the initiation of platform sedimentation and creation of sand shoal facies (Benevola Member) that was followed by the development of peritidal cyclicity (Daragan Member). Initiation of peritidal deposition coincided with the development of a rimmed platform that would persist throughout much of the Cambrian and Early Odrovician. At the end of deposition of the Waynesboro Formation, the platform became subaerially exposed because of the Hawke Bay regression, bringing the Sauk I supersequence to and end. In the Conestoga Valley of eastern Pennsylvania, Early Cambrian ramp deposition was succeeded by deposition of platform-margin and periplatfrom facies of the Kinzers Formation.

Role of non-governmental organizations in formation of non-proliferation culture in new independent countries (NIC)

International Nuclear Information System (INIS)

Sevchik, M.

2000-01-01

Purpose of the report is demonstrate the non-governmental organizations (NGO) role in formation of non-proliferation culture in former Soviet Union. Activity of Center of Non-proliferation Problems Investigation (CNPI) of Monterey Institute of International Investigations and its collaboration with existing in Commonwealth of Independent States (CIS) non-governmental organizations is considered as example. Brief information about CNPI and reasons for it representatives opening of in Kazakhstan and in other CIS-countries, as well as cooperation of NGO in Belarus, Kazakhstan, Russia and Ukraine for creation on Central Asia zone free from nuclear weapon ia given. Some measures which could promote to formation of non-proliferation culture in region are suggested

EARLY-STAGE MASSIVE STAR FORMATION NEAR THE GALACTIC CENTER: Sgr C

Energy Technology Data Exchange (ETDEWEB)

Kendrew, S.; Johnston, K.; Beuther, H. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Ginsburg, A.; Bally, J.; Battersby, C. [CASA, University of Colorado at Boulder, UCB 389, Boulder, CO 80309 (United States); Cyganowski, C. J., E-mail: kendrew@mpia.de [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

2013-10-01

We present near-infrared spectroscopy and 1 mm line and continuum observations of a recently identified site of high mass star formation likely to be located in the Central Molecular Zone (CMZ) near Sgr C. Located on the outskirts of the massive evolved H II region associated with Sgr C, the area is characterized by an Extended Green Object (EGO) measuring ∼10'' in size (0.4 pc), whose observational characteristics suggest the presence of an embedded massive protostar driving an outflow. Our data confirm that early-stage star formation is taking place on the periphery of the Sgr C H II region, with detections of two protostellar cores and several knots of H{sub 2} and Brackett γ emission alongside a previously detected compact radio source. We calculate the cores' joint mass to be ∼10{sup 3} M {sub ☉}, with column densities of 1-2 × 10{sup 24} cm{sup –2}. We show the host molecular cloud to hold ∼10{sup 5} M {sub ☉} of gas and dust with temperatures and column densities favorable for massive star formation to occur, however, there is no evidence of star formation outside of the EGO, indicating that the cloud is predominantly quiescent. Given its mass, density, and temperature, the cloud is comparable to other remarkable non-star-forming clouds such as G0.253 in the eastern CMZ.

Formation of stars and star clusters in colliding galaxies

International Nuclear Information System (INIS)

Belles, Pierre-Emmanuel

2012-01-01

Mergers are known to be essential in the formation of large-scale structures and to have a significant role in the history of galaxy formation and evolution. Besides a morphological transformation, mergers induce important bursts of star formation. These starburst are characterised by high Star Formation Efficiencies (SFEs) and Specific Star Formation Rates, i.e., high Star Formation Rates (SFR) per unit of gas mass and high SFR per unit of stellar mass, respectively, compared to spiral galaxies. At all redshifts, starburst galaxies are outliers of the sequence of star-forming galaxies defined by spiral galaxies. We have investigated the origin of the starburst-mode of star formation, in three local interacting systems: Arp 245, Arp 105 and NGC 7252. We combined high-resolution JVLA observations of the 21-cm line, tracing the HI diffuse gas, with UV GALEX observations, tracing the young star-forming regions. We probe the local physical conditions of the Inter-Stellar Medium (ISM) for independent star-forming regions and explore the atomic-to-dense gas transformation in different environments. The SFR/HI ratio is found to be much higher in central regions, compared to outer regions, showing a higher dense gas fraction (or lower HI gas fraction) in these regions. In the outer regions of the systems, i.e., the tidal tails, where the gas phase is mostly atomic, we find SFR/HI ratios higher than in standard HI-dominated environments, i.e., outer discs of spiral galaxies and dwarf galaxies. Thus, our analysis reveals that the outer regions of mergers are characterised by high SFEs, compared to the standard mode of star formation. The observation of high dense gas fractions in interacting systems is consistent with the predictions of numerical simulations; it results from the increase of the gas turbulence during a merger. The merger is likely to affect the star-forming properties of the system at all spatial scales, from large scales, with a globally enhanced turbulence

Colloquium on Central Asia; Colloque sur l'Asie centrale

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

This colloquium on Azerbaijan was organized by the direction of international relations of the French Senate and the French center of foreign trade (CFCE). This document gathers the interventions of the participants and the debates with the audience following these interventions. The topics treated concern: - the present day political-economical situation of Central Asia countries (problem of borders, relations with Russia and China); - the economies of Central Asia countries: short term problems and medium-term perspectives; - the relations with the European Union (political, economical, trade and investments, perspectives); - the European energy stakes of Caspian sea (oil and gas reserves, development of hydrocarbon resources, exploitation and transport constraints, stakes for Europe and France); - TotalFinaElf company in Central Asia (Kazakhstan, Azerbaijan, enclavement problem); - the economical impacts of the TRACECA pathway (Transport Corridor Europe Caucasus Asia). (J.S.)

Central San Juan caldera cluster: Regional volcanic framework

Science.gov (United States)

Lipman, Peter W.

2000-01-01

symmetrically resurgent Creede caldera, the volcanic framework for Lake Creede, has been exceptionally preserved because of rapid infilling by moat sediments of the Creede Formation, which were preferentially eroded during the past few million years. The ash-flow tuffs and caldera of the central San Juan region have been widely recognized as exceptional sites for study of explosive volcanic processes, and the results reported here provide new insights into processes of pyroclastic eruption and emplacement, geometric interrelations between caldera subsidence and resurgence, the petrologic diversity of sequential ash-flow eruptions, recurrent eruption of intermediate-composition lavas after each caldera-forming event, associated regional fault development, volume relations between ash-flow eruptions and associated calderas, the emplacement of subvolcanic batholiths, and involvement of mantle-derived mafic phases in magma-generation processes.

Formation-evolution model of uranium-productive basin and its recognition criteria

Energy Technology Data Exchange (ETDEWEB)

Zuyi, Chen; Ziying, Li [Beijing Research Inst. of Uranium Geology, Beijing (China); Weixun, Zhou; Taiyang, Guan [East China Inst. of Technology, Fuzhou (China)

2004-11-15

Based on geologic-tectonic setting and dynamic evolution of important U-productive basins both at home and abroad, authors distinguish six type of U-productive basins, and nominate each type by typical representative of this type, namely Chu-Sarysu and Syr-Darya type, Central Kyzylkum type, Zaural and West-Siberia type, Zabaikal type, Bohemia type, and South Texas type. The formation-evolution model of each type of U-productive basin has been established and recognition criteria have been proposed. Finially, the difference between each type U-productive basin is discussed and some assumption on prospecting for U-productive basins is proposed. (authors)