245 research outputs found
A Type-Theoretic Account of Neg-Raising Predicates in Tree Adjoining Grammars
International audienceNeg-Raising (NR) verbs form a class of verbs with a clausal complement that show the following behavior: when a negation syntactically attaches to the matrix predicate, it can semantically attach to the embedded predicate. This paper presents an account of NR predicates within Tree Adjoining Grammar (TAG). We propose a lexical semantic interpretation that heavily relies on a Montague-like semantics for TAG and on higher-order types
6-(2,6-Dimethylphenyl)pyrido[2,3-d]pyrimidin-7-amine
In the title compound, C15H14N4, the pyrido[2,3-d]pyrimidine system is almost ideally planar (r.m.s. deviation 0.028 Å) with its mean plane almost orthogonal to the 2,6-dimethylphenyl plane. The dihedral angle formed by these planes [87.3 (2)°] is close to the predicted value (89.7°) obtained by molecular-mechanics force-field calculations. Only one of the two active amine H atoms participates in hydrogen bonding, which links molecules into centrosymmetric dimers
Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments
An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion). Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG), within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG) and <i>Halobacteria</i>) within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes <i>Alphaproteobacteria</i>, <i>Betaproteobacteria</i> and <i>Gammaproteobacteria</i> within <i>Proteobacteria</i> phylum, and also members of <i>Bacteroidetes</i> phylum. The second most abundant lineages were <i>Actinobacteria</i> and <i>Firmicutes</i> at the Gulf of Lion site and <i>Chloroflexi</i> at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: <i>Alpha-</i>, <i>Gammaproteobacteria</i>, <i>Firmicutes</i> and <i>Actinobacteria</i>. In molecular surveys, the <i>Betaproteobacteria</i> group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea <i>levee</i>. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence analyses (CCA) showed that the availability of electron acceptors and the quality of electron donors (indicated by age) strongly influenced the community structure. In contrast, within the Gulf of Lion core, characterized by a homogeneous lithological structure of upper-slope environment, most detected groups were <i>Bacteroidetes</i> and, to a lesser extent, <i>Betaproteobacteria</i>. At both site, the detection of <i>Betaproteobacteria</i> coincided with increased terrestrial inputs, as confirmed by the geochemical measurements (Si, Sr, Ti and Ca). In the Gulf of Lion, geochemical parameters were also found to drive microbial community composition. Taken together, our data suggest that the palaeoenvironmental history of erosion and deposition recorded in the Western Mediterranean Sea sediments has left its imprint on the sedimentological context for microbial habitability, and then indirectly on structure and composition of the microbial communities during the late Quaternary
A systematic approach to performing a comprehensive transesophageal echocardiogram. A call to order
<p>Abstract</p> <p>Background</p> <p>While the order for a clinical transthoracic examination is fairly standardized, there is considerable variability between laboratories and even among physicians in the same laboratory with regard to the order for transesophageal echocardiograms (TEE). A systematic approach is desirable for more efficient use of physician and patient time, avoidance of inadvertent omission of important views, and to facilitate study review.</p> <p>Methods</p> <p>We propose a standardized approach to TEE data acquisition in which cardiac structures are systematically identified and characterized at sequential positions and imaging planes to facilitate organized, efficient and comprehensive assessment.</p> <p>Results</p> <p>Our approach to TEE study begins in the mid-esophagus with the imaging plane at 0°. Based on the specific indication for the TEE, a cardiac structure (e.g., mitral valve, left atrial appendage, or interatrial septum) is chosen as the primary focal point for a comprehensive, multiplane analysis. This structure is assessed in 20° – 30° increments as the imaging plane is advanced from 0° to 165°. Using the aortic valve as a reference point, pertinent cardiac structures are then assessed as the imaging plane is reduced to 135°, to 90°, to 40 – 60° and then back to 0°. The probe is then advanced into the stomach to obtain transgastric images at 0°, 90°, and 120°. Finally, the thoracic aorta and pulmonary artery are assessed as the probe is withdrawn from the body. Using this method, an organized and comprehensive TEE can be performed in 10 – 15 minutes.</p> <p>Conclusion</p> <p>A standardized and systematic TEE approach is described for efficient and comprehensive TEE study.</p
500,000 Years of Environmental History in Eastern Anatolia: The PALEOVAN Drilling Project
International Continental Scientific Drilling Program
(ICDP) drilled a complete succession of the lacustrine sediment
sequence deposited during the last ~500,000 years in
Lake Van, Eastern Anatolia (Turkey). Based on a detailed
seismic site survey, two sites at a water depth of up to 360 m
were drilled in summer 2010, and cores were retrieved from
sub-lake-floor depths of 140 m (Northern Basin) and 220 m
(Ahlat Ridge). To obtain a complete sedimentary section, the
two sites were multiple-cored in order to investigate the paleoclimate
history of a sensitive semi-arid region between the
Black, Caspian, and Mediterranean seas. Further scientific
goals of the PALEOVAN project are the reconstruction of
earthquake activity, as well as the temporal, spatial, and
compositional evolution of volcanism as reflected in the deposition
of tephra layers. The sediments host organic matter
from different sources and hence composition, which will be
unravelled using biomarkers. Pathways for migration of continental
and mantle-derived noble gases will be analyzed in
pore waters. Preliminary 40Ar/39Ar single crystal dating of
tephra layers and pollen analyses suggest that the Ahlat
Ridge record encompasses more than half a million years of
paleoclimate and volcanic/geodynamic history, providing
the longest continental record in the entire Near East to
date
Linguistic foundations of heritage language development from the perspective of romance languages in Germany
This paper discusses the role of different factors determining the linguistic competence of heritage speakers (HSs) based on examples from speakers who speak a Romance language (French, Italian, Portuguese, or Spanish) as heritage language (HL) and German as the environmental language. Since the relative amount of contact with the HL and the environmental language may vary during the acquisition process, the role of language dominance (in terms of relative language proficiency) is of particular interest for HL development. In addition to dominance (and related to it), cross-linguistic influence (CLI) may have an influence on the outcome of HL acquisition. Finally, quality and quantity of input also determine HL acquisition and will be discussed in connection with heritage language education.info:eu-repo/semantics/publishedVersio
Bacterial diversity and community composition from seasurface to subseafloor
© The International Society for Microbial Ecology, 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in ISME Journal 10 (2016): 979–989, doi:10.1038/ismej.2015.175.We investigated compositional relationships between bacterial communities in the water column and those in deep-sea sediment at three environmentally distinct Pacific sites (two in the Equatorial Pacific and one in the North Pacific Gyre). Through pyrosequencing of the v4–v6 hypervariable regions of the 16S ribosomal RNA gene, we characterized 450 104 pyrotags representing 29 814 operational taxonomic units (OTUs, 97% similarity). Hierarchical clustering and non-metric multidimensional scaling partition the samples into four broad groups, regardless of geographic location: a photic-zone community, a subphotic community, a shallow sedimentary community and a subseafloor sedimentary community (greater than or equal to1.5 meters below seafloor). Abundance-weighted community compositions of water-column samples exhibit a similar trend with depth at all sites, with successive epipelagic, mesopelagic, bathypelagic and abyssopelagic communities. Taxonomic richness is generally highest in the water-column O2 minimum zone and lowest in the subseafloor sediment. OTUs represented by abundant tags in the subseafloor sediment are often present but represented by few tags in the water column, and represented by moderately abundant tags in the shallow sediment. In contrast, OTUs represented by abundant tags in the water are generally absent from the subseafloor sediment. These results are consistent with (i) dispersal of marine sedimentary bacteria via the ocean, and (ii) selection of the subseafloor sedimentary community from within the community present in shallow sediment.This study was funded by the Biological Oceanography Program of the US National Science Foundation (grant OCE-0752336) and by the NSF-funded Center for Dark Energy Biosphere Investigations (grant NSF-OCE-0939564)
Formation of diagenetic siderite in modern ferruginous sediments
Ferruginous conditions prevailed in the world’s deep oceans during the Archean and Proterozoic Eons. Sedimentary iron formations deposited at that time may provide an important record of environmental conditions, yet linking the chemistry and mineralogy of these sedimentary rocks to depositional conditions remains a challenge due to a dearth of information about the processes by which minerals form in analogous modern environments. We identified siderites in ferruginous Lake Towuti, Indonesia, which we characterized using high-resolution microscopic and spectroscopic imaging combined with microchemical and geochemical analyses. We infer early diagenetic growth of siderite crystals as a response to sedimentary organic carbon degradation and the accumulation of dissolved inorganic carbon in pore waters. We suggest that siderite formation proceeds through syntaxial growth on preexisting siderite crystals, or possibly through aging of precursor carbonate green rust. Crystal growth ultimately leads to spar-sized (>50 μm) mosaic single siderite crystals that form twins, bundles, and spheroidal aggregates during burial. Early-formed carbonate was detectable through microchemical zonation and the possible presence of residual phases trapped in siderite interstices. This suggests that such microchemical zonation and mineral inclusions may be used to infer siderite growth histories in ancient sedimentary rocks including sedimentary iron formations
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