780 research outputs found

    Hiatus Avoidance and Metrification in the Rigveda

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    Using new corpus resources for Rigvedic poetics, we address various aspects of the poets\u27 treatment of vowel hiatus and pre-vocalic shortening (correption), including their strategies for avoidance of these phenomena in certain contexts. Using observed vs. expected tests, we demonstrate, for one, that hiatus avoidance is correlated with degree of metrical-prosodic juncture. For example, hiatus is actively avoided both at the caesura in trimeter verse and between padãs, but its avoidance is weaker in the latter case. In conducting these tests, we control for a confound (interference) from pre-vocalic shortening, which requires us to address the problem of whether it was optional or obligatory within the hemistich. It turns out that /V̄1#V22 patterns as metrically heavier than /Ṽ1#V2/ in the aggregated, though not as heave as /V̄C#V/. We then discuss different means by which the poets avoid setting up underlying hiatus junctures, including lexical avoidance (i.e., word selection), morphological avoidance (i.e., allomorph selection), and syntactic avoidance (i.e., word reordering). This last technique, whose existence we support with two different rests, is particularly striking, in that syntax (word order) is shown to be sensitive to phonotactics (marked junctures)

    The colometry of Tocharian 4X15-syllable verse

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    We identify the basic colometry of Tocharian 4x15-syllable verse as 4+3+3+5 (traditionally 7+8), but we find no support for the putative alternative colometries of 4x15 often cited in the literature (viz. 6+4+5 and 8+7). In rare cases in which the medial caesura is violated, a word boundary after syllable 6 or 8 is highly probable by chance alone, as we confirm through corpus statistics. If the colometry is indeed invariable, one major argument for the influence of Indic on Tocharian meter is undermined. We further reinforce that the medial caesura after syllable 7 is no stronger than the final one after syllable IO, despite their putative statuses as major vs. minor caesurae, respectively. The more complex picture of the metrical practice of the poets demands that we call into question certain proposed restorations

    Strategy for the identification of micro-organisms producing food and feed products : bacteria producing food enzymes as study case

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    Recent European regulations require safety assessments of food enzymes (FE) before their commercialization. FE are mainly produced by micro-organisms, whose viable strains nor associated DNA can be present in the final products. Currently, no strategy targeting such impurities exists in enforcement laboratories. Therefore, a generic strategy of first line screening was developed to detect and identify, through PCR amplification and sequencing of the 16S-rRNA gene, the potential presence of FE producing bacteria in FE preparations. First, the specificity was verified using all microbial species reported to produce FE. Second, an in-house database, with 16S reference sequences from bacteria producing FE, was constructed for their fast identification through blast analysis. Third, the sensitivity was assessed on a spiked FE preparation. Finally, the applicability was verified using commercial FE preparations. Using straightforward PCR amplifications, Sanger sequencing and blast analysis, the proposed strategy was demonstrated to be convenient for implementation in enforcement laboratories

    OTS 1809+314 and the Gamma-Ray Burst GB 790325b

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    We present deep CCD images of the field containing the recurring Optical Transient Source (OTS) 1809+314 recently discovered on the archival plates of the Sonneberg Observatory. At the position of OTS 1809+314 we find no optical counterpart brighter tha V=24.0 24.5, rgunn = 22.0-22.5 and I = 22.0 22.5, and I = 22.0-22.5. In the zero proper motion limit our observations place severe constraints on possible quiescent counterparts. There is no compelling evidence to suggest an association between the historical optical transient source and the gamma-ray burst GB 790325b located ~ 5\u27 to the east of OTS 1809+314

    INCORPORATING FIELD EFFECTS INTO THE DESIGN OF MODULAR PRODUCT FAMILIES

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    With advancing digitalization, new technologies with more and more digital components make it necessary to integrate new components into current and future products. Sensors and actuators, such as motors, emit electromagnetic and thermal fields that can greatly affect product performance. Recent work has considered fields at the functional level using functional structures and at the system level using DSM. In this paper, the effects of fields on product architecture are investigated at the component level. Using an appropriate visualization, the impact of fields on the product structure is considered. Architectural guidelines are then used to develop suitable product structures. The methodological approach is then applied to a product family of vacuum cleaner robots. The overlaid field information helps to gain deeper insights into the product architecture. The approach is useful for representing alternative structures. The new mapping of functional and structural relationships by moving module boundaries against fields can help promote architectural innovation

    Do Gamma-Ray Bursts Originate from an Extended Galactic Halo of High-Velocity Neutron Stars?

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    The γ-ray burst brightness distribution in inhomogeneous and the distribution on the sky is nearly isotropic. These features argue against an association with γ-ray bursts with those Galactic objects that are known to exhibit a strong concentration toward the Galactic center or plane. The observed statistical properties indicate a cosmological origin. Circumstantial evidence suggests that neutron stars are involved in the burst phenomenon. HEre we consdier Population II neutron stars in an extended Galatic Halo (EGH) as an alternative to cosmological scenaries. The BATSE data indicate a small deviation from isotropy near the 2 σ level of statistical significance. If confirmed for an increasing number of bursts, these anisotropies could rule out cosmological scenarios. On the other hand, EGH models require small anisotropies like those observed by BATSE. We consdier simple distribution models to determine the generic properties such halos must have to be consistent with the observations and discuss the implications of the corresponding distance scale on burst models

    Role of tyrosine M210 in the initial charge separation of reaction centers of Rhodobacter sphaeroides

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    Femtosecond spectroscopy was used in combination with site-directed mutagenesis to study the influence of tyrosine M210 (YM210) on the primary electron transfer in the reaction center of Rhodobacter sphaeroides. The exchange of YM210 to phenylalanine caused the time constant of primary electron transfer to increase from 3.5 f 0.4 ps to 16 f 6 ps while the exchange to leucine increased the time constant even more to 22 f 8 ps. The results suggest that tyrosine M210 is important for the fast rate of the primary electron transfer

    Trifluoromethylated Proline Surrogates as Part of "Pro-Pro" Turn-Inducing Templates

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    Proline is often found as a turn inducer in peptide or protein domains. Exploitation of its restricted conformational freedom led to the development of the d-Pro-l-Pro (corresponding to (R)-Pro-(S)-Pro) segment as a "templating" unit, frequently used in the design of beta-hairpin peptidomimetics, in which conformational stability is, however, inherently linked to the cis-trans isomerization of the prolyl amide bonds. In this context, the stereoelectronic properties of the CF3 group can aid in conformational control. Herein, the impact of alpha-trifluoromethylated proline analogues is examined for the design of enhanced beta-turn inducers. A theoretical conformational study permitted the dipeptide (R)-Pro-(R)-TfmOxa (TfmOxa: 2-trifluoromethyloxazolidine-2-carboxylic acid) to be selected as a template with an increased trans-cis rotational energy barrier. NMR spectroscopic analysis of the Ac-(R)-Pro-(R)-TfmOxa-(S)-Val-OtBu beta-turn model, obtained through an original synthetic pathway, validated the prevalence of a major trans-trans conformer and indicated the presence of an internal hydrogen bond. Altogether, it was shown that the (R)-Pro-(R)-TfmOxa template fulfilled all crucial beta-turn-inducer criteria

    Cerebellar c9RAN proteins associate with clinical and neuropathological characteristics of C9ORF72 repeat expansion carriers.

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    Clinical and neuropathological characteristics associated with G4C2 repeat expansions in chromosome 9 open reading frame 72 (C9ORF72), the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia, are highly variable. To gain insight on the molecular basis for the heterogeneity among C9ORF72 mutation carriers, we evaluated associations between features of disease and levels of two abundantly expressed "c9RAN proteins" produced by repeat-associated non-ATG (RAN) translation of the expanded repeat. For these studies, we took a departure from traditional immunohistochemical approaches and instead employed immunoassays to quantitatively measure poly(GP) and poly(GA) levels in cerebellum, frontal cortex, motor cortex, and/or hippocampus from 55 C9ORF72 mutation carriers [12 patients with ALS, 24 with frontotemporal lobar degeneration (FTLD) and 19 with FTLD with motor neuron disease (FTLD-MND)]. We additionally investigated associations between levels of poly(GP) or poly(GA) and cognitive impairment in 15 C9ORF72 ALS patients for whom neuropsychological data were available. Among the neuroanatomical regions investigated, poly(GP) levels were highest in the cerebellum. In this same region, associations between poly(GP) and both neuropathological and clinical features were detected. Specifically, cerebellar poly(GP) levels were significantly lower in patients with ALS compared to patients with FTLD or FTLD-MND. Furthermore, cerebellar poly(GP) associated with cognitive score in our cohort of 15 patients. In the cerebellum, poly(GA) levels similarly trended lower in the ALS subgroup compared to FTLD or FTLD-MND subgroups, but no association between cerebellar poly(GA) and cognitive score was detected. Both cerebellar poly(GP) and poly(GA) associated with C9ORF72 variant 3 mRNA expression, but not variant 1 expression, repeat size, disease onset, or survival after onset. Overall, these data indicate that cerebellar abnormalities, as evidenced by poly(GP) accumulation, associate with neuropathological and clinical phenotypes, in particular cognitive impairment, of C9ORF72 mutation carriers

    The Locations of Gamma-Ray Bursts Measured by COMPTEL

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    The COMPTEL instrument on the Compton Gamma Ray Observatory is used to measure the locations of gamma-ray bursts through direct imaging of MeV photons. In a comprehensive search, we have detected and localized 29 bursts observed between 1991 April 19 and 1995 May 31. The average location accuracy of these events is 1.25\arcdeg (1σ\sigma), including a systematic error of \sim0.5\arcdeg, which is verified through comparison with Interplanetary Network (IPN) timing annuli. The combination of COMPTEL and IPN measurements results in locations for 26 of the bursts with an average ``error box'' area of only \sim0.3 deg2^2 (1σ\sigma). We find that the angular distribution of COMPTEL burst locations is consistent with large-scale isotropy and that there is no statistically significant evidence of small-angle auto-correlations. We conclude that there is no compelling evidence for burst repetition since no more than two of the events (or \sim7% of the 29 bursts) could possibly have come from the same source. We also find that there is no significant correlation between the burst locations and either Abell clusters of galaxies or radio-quiet quasars. Agreement between individual COMPTEL locations and IPN annuli places a lower limit of \sim100~AU (95% confidence) on the distance to the stronger bursts.Comment: Accepted for publication in the Astrophysical Journal, 1998 Jan. 1, Vol. 492. 33 pages, 9 figures, 5 table
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