NASA Astrophysics Data System (ADS)
Golubkova, Anastasia; Schmidt, Max W.; Connolly, James A. D.
2016-05-01
Natural moissanite (SiC) is reported from mantle-derived samples ranging from lithospheric mantle keel diamonds to serpentinites to podiform chromitites in ophiolites related to suprasubduction zone settings (Luobusa, Dongqiao, Semail, and Ray-Iz). To simulate ultra-reducing conditions and the formation of moissanite, we compiled thermodynamic data for alloys (Fe-Si-C and Fe-Cr), carbides (Fe3C, Fe7C3, SiC), and Fe-silicides; these data were augmented by commonly used thermodynamic data for silicates and oxides. Computed phase diagram sections then constrain the P- T- fO2 conditions of SiC stability in the upper mantle. Our results demonstrate that: Moissanite only occurs at oxygen fugacities 6.5-7.5 log units below the iron-wustite buffer; moissanite and chromite cannot stably coexist; increasing pressure does not lead to the stability of this mineral pair; and silicates that coexist with moissanite have X Mg > 0.99. At upper mantle conditions, chromite reduces to Fe-Cr alloy at fO2 values 3.7-5.3 log units above the moissanite-olivine-(ortho)pyroxene-carbon (graphite or diamond) buffer (MOOC). The occurrence of SiC in chromitites and the absence of domains with almost Fe-free silicates suggest that ultra-reducing conditions allowing for SiC are confined to grain scale microenvironments. In contrast to previous ultra-high-pressure and/or temperature hypotheses for SiC origin, we postulate a low to moderate temperature mechanism, which operates via ultra-reducing fluids. In this model, graphite-/diamond-saturated moderately reducing fluids evolve in chemical isolation from the bulk rock to ultra-reducing methane-dominated fluids by sequestering H2O into hydrous phases (serpentine, brucite, phase A). Carbon isotope compositions of moissanite are consistent with an origin of such fluids from sediments originally rich in organic compounds. Findings of SiC within rocks mostly comprised by hydrous phases (serpentine + brucite) support this model. Both the hydrous phases
Revisiting 63Cu NMR evidence for charge order in superconducting La1.885Sr0.115CuO4
NASA Astrophysics Data System (ADS)
Imai, T.; Takahashi, S. K.; Arsenault, A.; Acton, A. W.; Lee, D.; He, W.; Lee, Y. S.; Fujita, M.
2017-12-01
The presence of charge and spin stripe order in the La2CuO4 -based family of superconductors continues to lead to new insight on the unusual ground-state properties of high-Tc cuprates. Soon after the discovery of charge stripe order at Tchargeâ65 K in Nd3 + co-doped La1.48Nd0.4Sr0.12CuO4 (Tcâ6 K) [Tranquada et al., Nature (London) 375, 561 (1995), 10.1038/375561a0], Hunt et al. demonstrated that La1.48Nd0.4Sr0.12CuO4 and superconducting La2 -xSrxCuO4 with x Ë1 /8 (Tcâ30 K) share nearly identical NMR anomalies near Tcharge of the former [Phys. Rev. Lett. 82, 4300 (1999), 10.1103/PhysRevLett.82.4300]. Their inevitable conclusion that La1.885Sr0.115CuO4 also undergoes charge order at a comparable temperature became controversial, because diffraction measurements at the time were unable to detect Bragg peaks associated with charge order. Recent advances in x-ray diffraction techniques finally led to definitive confirmations of the charge order Bragg peaks in La1.885Sr0.115CuO4 with an onset at as high as Tchargeâ80 K. Meanwhile, improved instrumental technology has enabled routine NMR measurements that were not feasible two decades ago. Motivated by these new developments, we revisit the charge order transition of a La1.885Sr0.115CuO4 single crystal based on 63Cu NMR techniques. We demonstrate that 63Cu NMR properties of the nuclear spin Iz=-1/2 to +1/2 central transition below Tcharge exhibit unprecedentedly strong dependence on the measurement time scale set by the separation time Ï between the 90â and 180â radio-frequency pulses; a new kind of anomalous, very broad winglike 63Cu NMR signals gradually emerge below Tcharge only for extremely short Ï â²4 μ s , while the spectral weight INormal of the normal NMR signals is progressively wiped out. The NMR linewidth and relaxation rates depend strongly on Ï below Tcharge, and their enhancement in the charge ordered state indicates that charge order turns on strong but inhomogeneous growth of Cu spin
NASA Astrophysics Data System (ADS)
Elitez, Ä°rem; Yaltırak, Cenk; Zabcı, Cengiz; Åahin, Murat
2015-04-01
The precise geological mapping is one of the most important issues in geological studies. Documenting the spatial distribution of geological bodies and their contacts play a crucial role on interpreting the tectonic evolution of any region. Although the traditional field techniques are still accepted to be the most fundamental tools in construction of geological maps, we suggest that the integration of digital technologies to the classical methods significantly increases the resolution and the quality of such products. We simply follow the following steps in integration of the digital data with the traditional field observations. First, we create the digital elevation model (DEM) of the region of interest by interpolating the digital contours of 1:25000 scale topographic maps to 10 m of ground pixel resolution. The non-commercial Google Earth satellite imagery and geological maps of previous studies are draped over the interpolated DEMs in the second stage. The integration of all spatial data is done by using the market leading GIS software, ESRI ArcGIS. We make the preliminary interpretation of major structures as tectonic lineaments and stratigraphic contacts. These preliminary maps are controlled and precisely coordinated during the field studies by using mobile tablets and/or phablets with GPS receivers. The same devices are also used in measuring and recording the geologic structures of the study region. Finally, all digitally collected measurements and observations are added to the GIS database and we finalise our geological map with all available information. We applied this integrated method to map the Burdur-Fethiye Shear Zone (BFSZ) in the southwest Turkey. The BFSZ is an active sinistral 60-to-90 km-wide shear zone, which prolongs about 300 km-long between Suhut-Cay in the northeast and KöyceÄiz Lake-Kalkan in the southwest on land. The numerous studies suggest contradictory models not only about the evolution but also about the fault geometry of this
NASA Astrophysics Data System (ADS)
Fiedukowicz, Anna; Gasiorowski, Jedrzej; Kowalski, PaweÅ; Olszewski, Robert; Pillich-Kolipinska, Agata
2012-11-01
The wide access to source data, published by numerous websites, results in situation, when
Three-dimensional repositioning accuracy of semiadjustable articulator cast mounting systems.
Tan, Ming Yi; Ung, Justina Youlin; Low, Ada Hui Yin; Tan, En En; Tan, Keson Beng Choon
2014-10-01
In spite of its importance in prosthesis precision and quality, the 3-dimensional repositioning accuracy of cast mounting systems has not been reported in detail. The purpose of this study was to quantify the 3-dimensional repositioning accuracy of 6 selected cast mounting systems. Five magnetic mounting systems were compared with a conventional screw-on system. Six systems on 3 semiadjustable articulators were evaluated: Denar Mark II with conventional screw-on mounting plates (DENSCR) and magnetic mounting system with converter plates (DENCON); Denar Mark 330 with in-built magnetic mounting system (DENMAG) and disposable mounting plates; and Artex CP with blue (ARTBLU), white (ARTWHI), and black (ARTBLA) magnetic mounting plates. Test casts with 3 high-precision ceramic ball bearings at the mandibular central incisor (Point I) and the right and left second molar (Point R; Point L) positions were mounted on 5 mounting plates (n=5) for all 6 systems. Each cast was repositioned 10 times by 4 operators in random order. Nine linear (Ix, Iy, Iz; Rx, Ry, Rz; Lx, Ly, Lz) and 3 angular (anteroposterior, mediolateral, twisting) displacements were measured with a coordinate measuring machine. The mean standard deviations of the linear and angular displacements defined repositioning accuracy. Anteroposterior linear repositioning accuracy ranged from 23.8 ±3.7 μm (DENCON) to 4.9 ±3.2 μm (DENSCR). Mediolateral linear repositioning accuracy ranged from 46.0 ±8.0 μm (DENCON) to 3.7 ±1.5 μm (ARTBLU), and vertical linear repositioning accuracy ranged from 7.2 ±9.6 μm (DENMAG) to 1.5 ±0.9 μm (ARTBLU). Anteroposterior angular repositioning accuracy ranged from 0.0084 ±0.0080 degrees (DENCON) to 0.0020 ±0.0006 degrees (ARTBLU), and mediolateral angular repositioning accuracy ranged from 0.0120 ±0.0111 degrees (ARTWHI) to 0.0027 ±0.0008 degrees (ARTBLU). Twisting angular repositioning accuracy ranged from 0.0419 ±0.0176 degrees (DENCON) to 0.0042 ±0.0038 degrees
A system for NMR stark spectroscopy of quadrupolar nuclei.
Tarasek, Matthew R; Kempf, James G
2010-05-13
Electrostatic influences on NMR parameters are well accepted. Experimental and computational routes have been long pursued to understand and utilize such Stark effects. However, existing approaches are largely indirect informants on electric fields, and/or are complicated by multiple causal factors in spectroscopic change. We present a system to directly measure quadrupolar Stark effects from an applied electric (E) field. Our apparatus and applications are relevant in two contexts. Each uses a radiofrequency (rf) E field at twice the nuclear Larmor frequency (2omega(0)). The mechanism is a distortion of the E-field gradient tensor that is linear in the amplitude (E(0)) of the rf E field. The first uses 2omega(0) excitation of double-quantum transitions for times similar to T(1) (the longitudinal spin relaxation time). This perturbs the steady state distribution of spin population. Nonlinear analysis versus E(0) can be used to determine the Stark response rate. The second context uses POWER (perturbations observed with enhanced resolution) NMR. Here, coherent, short-time (
Influence of bed surface changes on snow avalanche simulation
NASA Astrophysics Data System (ADS)
Fischer, Jan-Thomas; Issler, Dieter
2014-05-01
Gravitational flows, such as snow avalanches, are often modeled employing the shallowness assumption. The driving gravitational force has a first order effect on the dynamics of the flow, especially in complex terrain. Under suitable conditions, erosion and deposition during passage of the flow may change the bed surface by a similar amount as the flow depth itself. The accompanying changes of local slope angle and curvature are particularly significant at the side margins of the flow, where they may induce self-channeling and levée formation. Generally, one ought to expect visible effects wherever the flow depth and velocity are small, e.g., in deposition zones. Most current numerical models in practical use neglect this effect. In order to study the importance of these effects in typical applications, we modified the quasi-3D (depth-averaged) code MoT-Voellmy, which implements the well-known Voellmy friction law that is traditionally used in hazard mapping: The bed shear stress is given by Ïiz(h,u) = -ui(μgh cosθ+ ku2), ||u|| (1) with μ = O(0.1...0.5) and k = O(10-3...10-2) the dimensionless friction and drag coefficients, respectively. The leading curvature effects, i.e., extra friction due to centrifugal normal forces, are taken into account. The mass and momentum balances are solved by the (simplified) method of transport on a grid whose cells are squares when projected onto the horizontal plane. The direction of depth-averaging is everywhere perpendicular to the topographic surface. A simple erosion model is used. The erosion formula is based on the assumption that the snow cover behaves as a perfectly brittle solid with shear strength Ïc, above which it instantaneously fails. The erosion rate is derived from the balance of momentum across the interface between bed and flow, where there is a discontinuity of the shear stress, which is given by equation 1 just above the interface and by Ïc just below it according to the assumptions. This immediately
NASA Astrophysics Data System (ADS)
Tuccari, G.; Bezrukovs, Vl.; Nechaeva, M.
2012-12-01
can then allow exploring easily the desired range of search for unknown or not fully determined orbit objects. These features make Radar VLBI personality most useful in the space debris measurements. DBBC sistÄma izstrÄdÄta Noto Radioastronomijas institÅ«tÄ. SistÄmas galvenais
Clustering analysis of high-redshift luminous red galaxies in Stripe 82
NASA Astrophysics Data System (ADS)
Nikoloudakis, N.; Shanks, T.; Sawangwit, U.
2013-03-01
We present a clustering analysis of luminous red galaxies (LRGs) in Stripe 82 from the Sloan Digital Sky Survey (SDSS). We study the angular two-point autocorrelation function, w(θ), of a selected sample of over 130 000 LRG candidates via colour-cut selections in izK with the K-band coverage coming from UKIRT (United Kingdom Infrared Telescope) Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). We have used the cross-correlation technique of Newman to establish the redshift distribution of the LRGs. Cross-correlating them with SDSS quasi-stellar objects (QSOs), MegaZ-LRGs and DEEP Extragalactic Evolutionary Probe 2 (DEEP2) galaxies, implies an average redshift of the LRGs to be z â 1 with space density, ng â 3.20 ± 0.16 à 10-4 h3 Mpc-3. For θ ⤠10 arcmin (corresponding to â10 h-1 Mpc), the LRG w(θ) significantly deviates from a conventional single power law as noted by previous clustering studies of highly biased and luminous galaxies. A double power law with a break at rb â 2.4 h-1 Mpc fits the data better, with best-fitting scale length, r0, 1 = 7.63 ± 0.27 h-1 Mpc and slope γ1 = 2.01 ± 0.02 at small scales and r0, 2 = 9.92 ± 0.40 h-1 Mpc and γ2 = 1.64 ± 0.04 at large scales. Due to the flat slope at large scales, we find that a standard Î cold dark matter (Î CDM) linear model is accepted only at 2-3Ï, with the best-fitting bias factor, b = 2.74 ± 0.07. We also fitted the halo occupation distribution (HOD) models to compare our measurements with the predictions of the dark matter clustering. The effective halo mass of Stripe 82 LRGs is estimated as Meff = 3.3 ± 0.6 à 1013 h-1 Mâ. But at large scales, the current HOD models did not help explain the power excess in the clustering signal. We then compare the w(θ) results to the results of Sawangwit et al. from three samples of photometrically selected LRGs at lower redshifts to measure clustering evolution. We find that a long-lived model may be a poorer fit than at lower
NASA Astrophysics Data System (ADS)
Aizpurietis, P.; Vanags, M.; Kleperis, J.; Bajars, G.
2013-04-01
Hydrogen can be a good alternative to fossil fuels under the conditions of world's crisis as an effective energy carrier derived from renewable resources. Among all the known methods of hydrogen production, water electrolysis gives the ecologically purest hydrogen, so it is of importance to maximize the efficiency of this process. The authors consider the influence of plasma sprayed Ni-Al protective coating of 316L steel anode-cathode electrodes in DC electrolysis. In a long-term (24 h) process the anode corrodes strongly, losing Cr and Ni ions which are transferred to the electrolyte, while only minor corrosion of the cathode occurs. At the same time, the composition of anode and cathode electrodes protected by Ni-Al coating changes only slightly during a prolonged electrolysis. As the voltammetry and Tafel plots evidence, the Ni-Al coating protects both the anode and cathode from the corrosion and reduces the potential of hydrogen evolution. The results obtained show that such a coating works best in the case of steel electrodes. DarbÄ pÄtÄ«ts, kÄ lÄ«dzstrÄvas elektrolÄ«zÄ tÄrauda 316L elektrodus (anods un katods) ietekmÄ ar plazmas izputinÄÅ¡anas metodi iegÅ«ts Ni-Al pÄrklÄjums. Tikko uznestam pÄrklÄjumam ir mikrostrukturÄta virsma, kas kodinÄÅ¡anas laikÄ mainÄs, gan pÄc reljefa, gan elementu sastÄva. Veicot ilgstoÅ¡u (24 stundas elektrolÄ«zi), atrasts, ka tikai tÄrauda elektrods anoda lomÄ intensÄ«vi korodÄ un zaudÄ hroma un niÄ·eļa jonus, kas pÄriet elektrolÄ«tÄ, turpretÄ« katods mainÄs relatÄ«vi maz. PÄrklÄjums Ni-Al pÄc uzneÅ¡anas tiek kodinÄts karstÄ sÄrmÄ, kad tiek izÅ¡Ä·Ä«dinÄta daļa sastÄvÄ esoÅ¡o elementu (Al, Si, Cd), bet ilgstoÅ¡as elektrolÄ«zes laikÄ pÄrklÄjuma sastÄvs mainÄs maz gan anodam, gan katodam. Elektrodu elektroÄ·Ä«miskie raksturlielumi noteikti ar voltamperometrijas un TÄfeļa lÄ«kÅu analÄ«zes metodÄm. Atrasts, ka Ni-Al pÄrklÄjums aizsargÄ gan anodu, gan katodu no korozijas un samazina Å
2012-01-01
predicts the presence of novel trafficking-related components, and also the organizational logic that allows toxin diversification through recombination. Domain architecture and protein-length analysis revealed that these toxins might be deployed as secreted factors, through directed injection, or via inter-cellular contact facilitated by filamentous structures formed by RHS/YD, filamentous hemagglutinin and other repeats. Phyletic pattern and life-style analysis indicate that polymorphic toxins and polyimmunity loci participate in cooperative behavior and facultative âcheatingâ in several ecosystems such as the human oral cavity and soil. Multiple domains from these systems have also been repeatedly transferred to eukaryotes and their viruses, such as the nucleo-cytoplasmic large DNA viruses. Conclusions Along with a comprehensive inventory of toxins and immunity proteins, we present several testable predictions regarding active sites and catalytic mechanisms of toxins, their processing and trafficking and their role in intra-specific and inter-specific interactions between bacteria. These systems provide insights regarding the emergence of key systems at different points in eukaryotic evolution, such as ADP ribosylation, interaction of myosin VI with cargo proteins, mediation of apoptosis, hyphal heteroincompatibility, hedgehog signaling, arthropod toxins, cell-cell interaction molecules like teneurins and different signaling messengers. Reviewers This article was reviewed by AM, FE and IZ. PMID:22731697
Zhang, Zhongge; Pierson, Leland S.
2001-01-01
The root-associated biological control bacterium Pseudomonas aureofaciens 30-84 produces a range of exoproducts, including protease and phenazines. Phenazine antibiotic biosynthesis by phzXYFABCD is regulated in part by the PhzR-PhzI quorum-sensing system. Mutants defective in phzR or phzI produce very low levels of phenazines but wild-type levels of exoprotease. In the present study, a second genomic region of strain 30-84 was identified that, when present in trans, increased β-galactosidase activity in a genomic phzB::lacZ reporter and partially restored phenazine production to a phzR mutant. Sequence analysis identified two adjacent genes, csaR and csaI, that encode members of the LuxR-LuxI family of regulatory proteins. No putative promoter region is present upstream of the csaI start codon and no lux box-like element was found in either the csaR promoter or the 30-bp intergenic region between csaR and csaI. Both the PhzR-PhzI and CsaR-CsaI systems are regulated by the GacS-GacA two-component regulatory system. In contrast to the multicopy effects of csaR and csaI in trans, a genomic csaR mutant (30-84R2) and a csaI mutant (30-84I2) did not exhibit altered phenazine production in vitro or in situ, indicating that the CsaR-CsaI system is not involved in phenazine regulation in strain 30-84. Both mutants also produced wild-type levels of protease. However, disruption of both csaI and phzI or both csaR and phzR eliminated both phenazine and protease production completely. Thus, the two quorum-sensing systems do not interact for phenazine regulation but do interact for protease regulation. Additionally, the CsaI N-acylhomoserine lactone (AHL) signal was not recognized by the phenazine AHL reporter 30-84I/Z but was recognized by the AHL reporters Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136(pCF240). Inactivation of csaR resulted in a smooth mucoid colony phenotype and formation of cell aggregates in broth, suggesting that CsaR is involved in
NASA Astrophysics Data System (ADS)
Favale, T.; De Angelis, F.; De Filippis, L.
2012-04-01
The high school Liceo Scientifico "Lazzaro Spallanzani" at Tivoli (Rome) has been fully involved in the study of geological and geophysical features of the town of Tivoli and the surrounding area in the last twelve years. Objective of this activity is to promote the knowledge of the local territory from the geological point of view. Main activities: ⢠School year 2001-2002: Setting up inside the school building of a Geological Museum focusing on "Geological Evolution of Latium, Central Italy" (in collaboration with colleagues M. Mancini, and A. Pierangeli). ⢠March, 15, 2001: Conference of Environmental Geology. Lecturer: Prof. Raniero Massoli Novelli, L'Aquila University and Società Italiana di Geologia Ambientale. ⢠School years 2001-2002 and 2002-2003: Earth Sciences course for students "Brittle deformation and tectonic stress in Tivoli area". ⢠November, 2003: Conference of Geology, GIS and Remote Sensing. Lecturers: Prof. Maurizio Parotto and Dr Alessandro Cecili (Roma Tre University, Rome), and Dr Stefano Pignotti (Istituto Nazionale per la Ricerca sulla Montagna, Rome). ⢠November, 2003, 2004 and 2005: GIS DAY, organized in collaboration with ESRI Italia. ⢠School year 2006-2007: Earth Sciences course for students "Acque Albule basin and the Travertine of Tivoli, Latium, Central Italy" (focus on travertine formation). ⢠School year 2010-2011: Earth Sciences course for students "Acque Albule basin and the Travertine of Tivoli. Geology, Hydrogeology and Microbiology of the basin, Latium, Central Italy" (focus on thermal springs and spa). In the period 2009-2010 a seismic station with three channels, currently working, was designed and built in our school by the science teachers Felice De Angelis and Tomaso Favale. Our seismic station (code name LTTV) is part of Italian Experimental Seismic Network (IESN) with identification code IZ (international database IRIS-ISC). The three drums are online in real time on websites http
Climatic record of the Iberian peninsula from lake Moncortes' sediments
NASA Astrophysics Data System (ADS)
Cao, Min; Huguet, Carme; Rull, Valenti; Valero, Blas; Rosell-Mele, Antoni
2014-05-01
.19km2. Lake Moncortes is situated at 1065 m above sea level, has an average temperature of 10ºC (minimum 3 and maximum 16ºC) and a mean annual precipitation of 770mm. We used the MBT/CBT (Weijers et al. 2007) proxy of pH and terrestrial temperature and the TEX86 temperature proxy (Schouten et al. 2002) to estimate changes in and around the lake. Both proxies are based on the glycerol dialkyl glycerol tetraethers (GDGTs) of archaea (isoprenoid GDGTs) and bacteria (branched GDGTs) origin. We also measured soils surrounding the lake (Menges et al. 2013) in order to establish end-members for the proxies as well as organic matter transport. Data on n-alkane isotopes will help establish hydrographic regime changes. We observe changes in temperature and humidity consistent with those on teh northern hemisphere. J. Menges, C. Huguet, J.M. Alcañiz, S. Fietz, D. Sachse, A. Rosell-Melé Biogechemistry discussions (2013), BGD bg-2013-198. S. Schouten, E.C. Hopmans, E. Schefuss, J.S.S. Damste, Earth and Planetary Science Letters 204(2002) 265-274 J.W.H. Weijers, S. Schouten, J.S.S. Damste, Geochimica Et Cosmochimica Acta 71(2007) A1098-A1098.
Bogdanov, N A
The article contains the results of the ecological and hygienic diagnostics of conditions of lands of areas of different sizes and varying degrees of urbanization, located in different agro-climatic conditions of European Russia (the southern Astrakhan region, he city of Moscow). Assessments of the state of territories use a new approach to rationing of Hg according to quantitative ratios of the content of its thermoforms in soils, grounds and alluvium (in litho substrate). The method of diagnostics is based on known properties of Hg forms: their geochemical activity (migration mobility) and toxicity decline along with the increment of the Hg temperature threshold of the release in the process of continuous warming up of the litho substrate sample (up to 1100°C). Thermoforms are not tied to specific minerals or chemicals and are conditionally designated as FR (Free: <180°C), CL (Chloride: 180-250°C), FS and CS (physically and chemically sorbed: 250-400°C), SU (Sulfide: 400-500°C) IS (isomorphic: >500°C) Hg forms. Among forms, also conditionally according to complexes of low, medium and high temperature variations(FR + CL, FS + CS and SU + IZ, respectively, there are selected groups of «mobile», «sustainable» and «inert» forms. For technogenic Hg there is characterized the predominance in the sample of «mobile» and to lesser extent degree - «stable» thermoforms. The more intensive this predominance is, the higher is environmental hazard. The natural accumulation is diagnosed by the presence and prevalence of the sum of moderate - and high-temperature inert forms of Hg. According to the ratios of Hg content, its forms and groups, as well as the density of correlationships between them, 6 indices of the conditions of soils and alluvium were developed by ourselves.Main coefficients out of indices on informativeness of results of diagnostics are the following factors: Endogenous input, Geochemical activity and Hg mobility. With regard to the combination
Salih, Enass Y A; Julkunen-Tiitto, Riitta; Lampi, Anna-Maija; Kanninen, Markku; Luukkanen, Olavi; Sipi, Marketta; Lehtonen, Mari; Vuorela, Heikki; Fyhrquist, Pia
2018-05-04
Terminalia laxiflora Engl. & Diels, (Sudanese Arabic name: Darout اÙدرÙت) and Terminalia brownii Fresen (Sudanese Arabic name: Alshaf Ø£ÙشاÙ) (Combretaceae) are used in Sudanese traditional folk medicine and in other African countries for treatment of infectious diseases, TB and its symptoms, such as cough, bronchitis and chest pain. Because of the frequent use of T. laxiflora and T. brownii in African traditional medicine and due to the absence of studies regarding their antimycobacterial potential there was a need to screen extracts of T. laxiflora and T. brownii for their growth inhibitory potential and to study the chemical composition and compounds in growth inhibitory extracts. The plant species were collected in Sudan (Blue Nile Forest, Ed Damazin Forestry areas) and selected according to their uses in traditional medicine for the treatment of bacterial infections, including TB. Eighty extracts and fractions of the stem bark, stem wood, roots, leaves and fruits of T. laxiflora and T. brownii and nine pure compounds present in the active extracts were screened against Mycobacterium smegmatis ATCC 14468 using agar diffusion and microplate dilution methods. Inhibition zones and MIC values were estimated and compared to rifampicin. HPLC-UV/DAD, GC/MS and UHPLC/Q-TOF MS were employed to identify the compounds in the growth inhibitory extracts. The roots of T. laxiflora and T. brownii gave the best antimycobacterial effects (IZ 22-27mm) against Mycobacterium smegmatis. The lowest MIC of 625µg/ml was observed for an acetone extract of the root of T. laxiflora followed by methanol and ethyl acetate extracts, both giving MIC values of 1250µg/ml. Sephadex LH-20 column chromatography purification of T. brownii roots resulted in low MIC values of 62.5µg/ml and 125µg/ml for acetone and ethanol fractions, respectively, compared to 5000µg/ml for the crude methanol extract. Methyl (S)-flavogallonate is suggested to be the main active compound in the Sephadex
NASA Astrophysics Data System (ADS)
Reylé, C.; Delorme, P.; Willott, C. J.; Albert, L.; Delfosse, X.; Forveille, T.; Artigau, E.; Malo, L.; Hill, G. J.; Doyon, R.
2010-11-01
Context. Thanks to recent and ongoing large scale surveys, hundreds of brown dwarfs have been discovered in the last decade. The Canada-France Brown Dwarf Survey is a wide-field survey for cool brown dwarfs conducted with the MegaCam camera on the Canada-France-Hawaii Telescope. Aims: Our objectives are to find ultracool brown dwarfs and to constrain the field brown-dwarf luminosity function and the mass function from a large and homogeneous sample of L and T dwarfs. Methods: We identify candidates in CFHT/MegaCam i' and z' images and follow them up with pointed near infrared (NIR) imaging on several telescopes. Halfway through our survey we found ~50 T dwarfs and ~170 L or ultra cool M dwarfs drawn from a larger sample of 1400 candidates with typical ultracool dwarfs i'-z' colours, found in 780 square degrees. Results: We have currently completed the NIR follow-up on a large part of the survey for all candidates from mid-L dwarfs down to the latest T dwarfs known with utracool dwarfs' colours. This allows us to draw on a complete and well defined sample of 102 ultracool dwarfs to investigate the luminosity function and space density of field dwarfs. Conclusions: We found the density of late L5 to T0 dwarfs to be 2.0+0.8-0.7 Ã 10-3 objects pc-3, the density of T0.5 to T5.5 dwarfs to be 1.4+0.3-0.2 Ã 10-3 objects pc-3, and the density of T6 to T8 dwarfs to be 5.3+3.1-2.2 Ã 10-3 objects pc-3. We found that these results agree better with a flat substellar mass function. Three latest dwarfs at the boundary between T and Y dwarfs give the high density 8.3+9.0-5.1 Ã 10-3 objects pc-3. Although the uncertainties are very large this suggests that many brown dwarfs should be found in this late spectral type range, as expected from the cooling of brown dwarfs, whatever their mass, down to very low temperature. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by
Robles, Rebeca; Fresán, Ana; Vega-RamÃrez, Hamid; Cruz-Islas, Jeremy; RodrÃguez-Pérez, Victor; DomÃnguez-MartÃnez, Tecelli; Reed, Geoffrey M
2016-09-01
for body transformation, most commonly hormones (182 [73%)], with the first such intervention at a mean age of 25·0 years (SD 9·1, range 10-54). 84 (46%) of those who had used hormones did so initially without medical supervision. During adolescence, distress related to gender identity was very common, but not universal (n=208 [83%]), and average level of distress was quite high among those who reported it (79·9 on a scale of 0 [none at all] to 100 [extreme], SD 20·7, range 20-100). Most participants (n=226 [90%] reported experiencing family, social, or work or scholastic dysfunction related to their gender identity, but this was typically moderate (on a scale of 0 [not at all disrupted] to 10 [extremely disrupted], family dysfunction mean 5·3 [SD 3·9, range 0-10]; social dysfunction mean 5·0 [SD 3·8, range 0-10]; work or scholastic dysfunction mean 4·8 [SD 3·6, range 0-10]). Multivariate logistic regression models indicated that distress and all types of dysfunction were strongly predicted by experiences of social rejection (odds ratios [ORs] 2·29-8·15) and violence (1·99-3·99). A current male gender identity also predicted distress (OR 3·90). Of the indicators of gender incongruence, only asking to be treated as a different gender was a significant predictor, and only of work or scholastic dysfunction (OR 1·82). This study provides additional support for classifying health-related categories related to transgender identity outside the classification of mental disorders in the ICD-11. The reconceptualisation and related reclassification of transgender-related health conditions in the ICD-11 could serve as a useful instrument in the discussion of public health policies aimed at increasing access to appropriate services and reducing the victimisation of transgender people. National Institute of Psychiatry Ramón de la Fuente Muñiz, Mexico. Copyright © 2016 Elsevier Ltd. All rights reserved.
VizieR Online Data Catalog: OCARS catalog second version (Malkin, 2016)
NASA Astrophysics Data System (ADS)
Malkin, Z. M.
2016-11-01
Unlike the first version, supported in 2007-2015, the second version of the OCARS catalog includes three files: ocars.txt is the main file containing the source coordinates, source types, redshifts, and approximate magnitudes, together with commentary; this file corresponds to the first version of the OCARS catalog; ocars_m.txt contains photometric data in the 13 uUBgV rRiIzJHK bands; ocars_n.txt contains a table of corresponding source names in various catalogs; currently, only cross-identifications with IVS programs4 and the LQAC catalog [9] are included; The list of objects included in the OCARS catalog is formed from various astrometric and geodeticVLBI programs and catalogs in the following order: - sources in the ICRF2 [2]; - other sources observed in the framework of IVS programs; - sources from the NASA Goddard VLBI group catalog5 ; - sources from the RFC catalog,6 which is the most complete astrometric catalog of radio sources, is updated each quarter, and contributed more than half the OCARS objects; the latest version of OCARS used the RFC-2016a catalog based on observations obtained in 1980-2015 as part of IVS and other radio astrometric programs [19-31]; - sources from the literature. Optical Characteristics of Astrometric Radio Sources (OCARS) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Last revised: 27-NOV-2016 Latest update: - removed 30+ RFC sources not identified in NED and optics - removed rather long detailed statistics table, which seems to be not interested for most of users; it is always available on request - a few additions and amendments E-mail alerts about updates are available on request. URL of this file is http
NASA Astrophysics Data System (ADS)
Fan, Xiaohui; Narayanan, Vijay K.; Lupton, Robert H.; Strauss, Michael A.; Knapp, Gillian R.; Becker, Robert H.; White, Richard L.; Pentericci, Laura; Leggett, S. K.; Haiman, Zoltán; Gunn, James E.; IveziÄ, Željko; Schneider, Donald P.; Anderson, Scott F.; Brinkmann, J.; Bahcall, Neta A.; Connolly, Andrew J.; Csabai, István; Doi, Mamoru; Fukugita, Masataka; Geballe, Tom; Grebel, Eva K.; Harbeck, Daniel; Hennessy, Gregory; Lamb, Don Q.; Miknaitis, Gajus; Munn, Jeffrey A.; Nichol, Robert; Okamura, Sadanori; Pier, Jeffrey R.; Prada, Francisco; Richards, Gordon T.; Szalay, Alex; York, Donald G.
2001-12-01
We present the results from a survey of i-dropout objects selected from ~1550 deg2 of multicolor imaging data from the Sloan Digital Sky Survey to search for luminous quasars at z>~5.8. Objects with i*-z*>2.2 and z*<20.2 are selected, and follow-up J-band photometry is used to separate L- and T-type cool dwarfs from high-redshift quasars. We describe the discovery of three new quasars, SDSSp J083643.85+005453.3 (z=5.82), J130608.26+035626.3 (z=5.99), and J103027.10+052455.0 (z=6.28). The quasar SDSSp J083643.85+005453.3 is a radio source with flux of 1.1 mJy at 20 cm. The spectra of all three quasars show strong and broad Lyα+N V emission lines and very strong Lyα forest absorption, with a mean continuum decrement DA>0.90. The ARC 3.5 m spectrum of SDSSp J103027.10+052455.0 shows that over a range of ~300 à immediately blueward of the Lyα emission, the average transmitted flux is only 0.003+/-0.020 times that of the continuum level, consistent with zero flux over a ~300 à range of the Lyα forest region and suggesting a tentative detection of the complete Gunn-Peterson trough. The existence of strong metal lines in the quasar spectra suggests early metal enrichment in the quasar environment. The three new objects, together with the previously published z=5.8 quasar SDSSp J104433.04-012502.2, form a complete color-selected flux-limited sample at z>~5.8. We estimate the selection function of this sample, taking into account the estimated variations in the quasar spectral energy distribution, as well as observational photometric errors. We find that at z=6, the comoving density of luminous quasars at M1450<-26.8 (H0=50 km s-1 Mpc-1, Ω=1) is 1.1Ã10-9 Mpc-3. This is a factor of ~2 lower than that at z~5 and is consistent with an extrapolation of the observed quasar evolution at z<5. Using the current sample, we discuss the constraint on the shape of the quasar luminosity function and the implications for the contribution of quasars to the ionizing background at z
