990 research outputs found

    HABITAT CHARACTERISTICS AND DEMOGRAPHY OF CALYPSO BULBOSA AND CYPRIPEDIUM ARIETINUM IN THE GRAND SABLE DUNES, MICHIGAN

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    This is a study of the distribution, habitat characteristics, and reproductive demography of Calypso bulbosa and Cypripedium arietinum in the Grand Sable Dunes, Pictured Rocks National Lakeshore, Michigan, USA. Data for Cypripedium arietinum was collected from 345, 1-m radius plots in a stratified (by island) random sampling design. The total number of C. arietinum in 2009 was 3,596,000 (95% CI= 2,645,000-4,547,000). C. arietinum has several close vegetative associates, including Chimaphila umbellata and the moss Pleurozium schreberi. The population appears to be stable to expanding. Nearly 100 Calypso bulbosa were monitored in eight, 4 x 4-m permanent plots from 2008 to 2014. The minimum number of Calypso bulbosa in the Grand Sable Dunes was 321 plants in 2008; however, over the 6-year period (2008-2014) that number declined 40.5% with all plots pooled (mean=41.4%, SD=28.4, n=8 plots). The habitat models of Calypso show that it is strongly associated with several other orchids, and occurs primarily in moist swales. Climate change may have a tremendous impact on the Grand Sable Dunes and its plant communities. The long-term effects of climate change on these orchids and their associated mycorrhizae are unknown

    Is periodontitis and its treatment capable of changing the quality of life of a patient?

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    While clinical indicators, or so-called surrogate outcomes in periodontology, allow us to assess periodontal health and evaluate outcomes of periodontal therapy from a clinician's perspective, they cannot be used to evaluate patients' subjective perceptions of their health status or satisfaction with the received treatment. These can be assessed through patient-based outcomes, such as quality of life. The aim of this paper is to give an overview of the multidimensional concept of oral health-related quality of life (OHRQoL), its measures and association with plaque-induced, inflammatory periodontal diseases. Periodontitis and its clinical consequences, such as tooth loss, have a considerable negative effect on OHRQoL, while periodontal treatment and alleviation of the symptoms can lead to improvement in OHRQoL. Implant rehabilitation of missing teeth also seems to positively influence OHRQo

    Determinants of innovation in Croatian SMEs – comparison of service and manufacturing firms

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    Purpose – In this paper we focus on SMEs in Croatia operating in the manufacturing and services sectors, and seek to compare them in terms of their involvement in innovation activities, and the factors determining their decision to innovate, in general and in four types of innovations in particular: product/service, process, organizational and marketing innovations. Design/Methodology/Approach – The analysis relies on the Croatian Community Innovation Survey 2010 (CIS 2010) data. To find out whether innovations have a different pattern of drivers in manufacturing and in services, we estimate the probit and multivariate probit models separately on these two groups of firms. Findings and implications – The findings reveal that, despite some differences, service and manufacturing SMEs are not that different from one another when it comes to innovation activities. Service SMEs are somewhat less likely to introduce technological innovations, but manufacturing and service SMEs do not differ significantly when it comes to non-technological innovations. One noteworthy difference between manufacturing and service SMEs is that the latter rely on acquired knowledge much more than do the former. Limitation – One limitation of the study is that most variables in the CIS dataset, including those on innovations, are of a binary nature, a fact that dictated the choice of the econometric model. In addition, the data pertain to the time period of an economic downturn in Croatia, which possibly affected the results obtained. Originality – This research contributes to understanding the drivers of innovation activities in SMEs and differences in this regard between manufacturing and services in Croatia

    Palladium(II) complexes of quinolinylaminophosphonates: synthesis, structural characterization, antitumor and antimicrobial activity

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    Three types of palladium(II) halide complexes of quinolinylaminophosphonates have been synthesized and studied. Diethyl and dibutyl [alpha-anilino-(quinolin-2-ylmethyl)]phosphonates (L1, 12) act as N,N-chelate ligands through the quinoline and aniline nitrogens giving complexes cis-[Pd(L1/12)X-2] (X Cl, Br) (1-4). Their 3-substituted analogues [alpha-anilino-(quinolin-3-ylmethyl)]phosphonates (L3, L4) form dihalidopalladium complexes trans-[Pd(L3/L4)(2)X-2] (5-8), with trans N-bonded ligand molecules only through the quinoline nitrogen. Dialkyl [alpha-(quinolin-3-ylamino)-N-benzyl]phosphonates (L5, L6) give tetrahalidodipalladium complexes [Pd-2(L5/L6)(3)X-4] (9-12), containing one bridging and two terminal ligand molecules. The bridging molecule is bonded to the both palladium atoms, one through the quinoline and the other through the aminoquinoline nitrogen, whereas terminal ligand molecules are coordinated each only to one palladium via the quinoline nitrogen. Each palladium ion is also bonded to two halide ions in a trans square-planar fashion. The new complexes were identified and characterized by elemental analyses and by IR, UV-visible, H-1, C-13 and P-31 nuclear magnetic resonance and ESI-mass spectroscopic studies. The crystal structures of complexes 1-4 and 6 were determined by X-ray structure analysis. The antitumor activity of complexes in vitro was investigated on several human tumor cell lines and the highest activity with cell growth inhibitory effects in the low micromolar range was observed for dipalladium complexes 11 and 12 derived from dibutyl ester L6. The antimicrobial properties in vitro of ligands and their complexes were studied using a wide spectrum of bacterial and fungal strains. No specific activity was noted. Only ligands L3 and L4 and tetrahalidodipalladium complexes 9 and 11 show poor activities against some Gram positive bacteria

    Formation and Interaction of Membrane Tubes

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    We show that the formation of membrane tubes (or membrane tethers), which is a crucial step in many biological processes, is highly non-trivial and involves first order shape transitions. The force exerted by an emerging tube is a non-monotonic function of its length. We point out that tubes attract each other, which eventually leads to their coalescence. We also show that detached tubes behave like semiflexible filaments with a rather short persistence length. We suggest that these properties play an important role in the formation and structure of tubular organelles.Comment: 4 pages, 3 figure

    Stresses in lipid membranes

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    The stresses in a closed lipid membrane described by the Helfrich hamiltonian, quadratic in the extrinsic curvature, are identified using Noether's theorem. Three equations describe the conservation of the stress tensor: the normal projection is identified as the shape equation describing equilibrium configurations; the tangential projections are consistency conditions on the stresses which capture the fluid character of such membranes. The corresponding torque tensor is also identified. The use of the stress tensor as a basis for perturbation theory is discussed. The conservation laws are cast in terms of the forces and torques on closed curves. As an application, the first integral of the shape equation for axially symmetric configurations is derived by examining the forces which are balanced along circles of constant latitude.Comment: 16 pages, introduction rewritten, other minor changes, new references added, version to appear in Journal of Physics

    Copper(I) dye-sensitized solar cells with [Co(bpy)3]2+/3+ electrolyte

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    The hierarchical assembly of DSCs containing a new heteroleptic copper(I) complex with a phosphonic acid anchoring ligand is described; it is shown that conventional I−/I3− electrolytes may be replaced by [Co(bpy)3]2+/3+ with no loss in performance

    Properties and nature of Be stars: 27. Orbital and recent long-term variations of the Pleiades Be star Pleione = BU Tauri

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    Radial-velocity variations of the H-alpha emission measured on the steep wings of the H-alpha line, prewhitened for the long-time changes, vary periodically with a period of (218.025 +/- 0.022)d, confirming the suspected binary nature of the bright Be star Pleione, a member of the Pleiades cluster. The orbit seems to have a high eccentricity over 0.7, but we also briefly discuss the possibility that the true orbit is circular and that the eccentricity is spurious owing to the phase-dependent effects of the circumstellar matter. The projected angular separation of the spectroscopic orbit is large enough to allow the detection of the binary with large optical interferometers, provided the magnitude difference primary - secondary is not too large. Since our data cover the onset of a new shell phase up to development of a metallic shell spectrum, we also briefly discuss the recent long-term changes. We confirm the formation of a new envelope, coexisting with the previous one, at the onset of the new shell phase. We find that the full width at half maximum of the H-alpha profile has been decreasing with time for both envelopes. In this connection, we briefly discuss Hirata's hypothesis of precessing gaseous disk and possible alternative scenarios of the observed long-term changes

    Constraining Disk Parameters of Be Stars using Narrowband H-alpha Interferometry with the NPOI

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    Interferometric observations of two well-known Be stars, gamma Cas and phi Per, were collected and analyzed to determine the spatial characteristics of their circumstellar regions. The observations were obtained using the Navy Prototype Optical Interferometer equipped with custom-made narrowband filters. The filters isolate the H-alpha emission line from the nearby continuum radiation, which results in an increased contrast between the interferometric signature due to the H-alpha-emitting circumstellar region and the central star. Because the narrowband filters do not significantly attenuate the continuum radiation at wavelengths 50 nm or more away from the line, the interferometric signal in the H-alpha channel is calibrated with respect to the continuum channels. The observations used in this study represent the highest spatial resolution measurements of the H-alpha-emitting regions of Be stars obtained to date. These observations allow us to demonstrate for the first time that the intensity distribution in the circumstellar region of a Be star cannot be represented by uniform disk or ring-like structures, whereas a Gaussian intensity distribution appears to be fully consistent with our observations.Comment: 23 pages, 14 figures, accepted for publication in A
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