13,082 research outputs found

    A rapid staining-assisted wood sampling method for PCR-based detection of pine wood nematode Bursaphelenchus xylophilus in Pinus massoniana wood tissue

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    For reasons of unequal distribution of more than one nematode species in wood, and limited availability of wood samples required for the PCR-based method for detecting pinewood nematodes in wood tissue of Pinus massoniana, a rapid staining-assisted wood sampling method aiding PCR-based detection of the pine wood nematode Bursaphelenchus xylophilus (Bx) in small wood samples of P. massoniana was developed in this study. This comprised a series of new techniques: sampling, mass estimations of nematodes using staining techniques, and lowest limit Bx nematode mass determination for PCR detection. The procedure was undertaken on three adjoining 5-mg wood cross-sections, of 0.5 · 0.5 · 0.015 cm dimension, that were cut from a wood sample of 0.5 · 0.5 · 0.5 cm initially, then the larger wood sample was stained by acid fuchsin, from which two 5-mg wood cross-sections (that adjoined the three 5-mg wood cross-sections, mentioned above) were cut. Nematode-staining-spots (NSSs) in each of the two stained sections were counted under a microscope at 100· magnification. If there were eight or more NSSs present, the adjoining three sections were used for PCR assays. The B. xylophilus – specific amplicon of 403 bp (DQ855275) was generated by PCR assay from 100.00% of 5-mg wood cross-sections that contained more than eight Bx NSSs by the PCR assay. The entire sampling procedure took only 10 min indicating that it is suitable for the fast estimation of nematode numbers in the wood of P. massonina as the prelimary sample selections for other more expensive Bx-detection methods such as PCR assay

    Evolution equations of curvature tensors along the hyperbolic geometric flow

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    We consider the hyperbolic geometric flow 2t2g(t)=2Ricg(t)\frac{\partial^2}{\partial t^2}g(t)=-2Ric_{g(t)} introduced by Kong and Liu [KL]. When the Riemannian metric evolve, then so does its curvature. Using the techniques and ideas of S.Brendle [Br,BS], we derive evolution equations for the Levi-Civita connection and the curvature tensors along the hyperbolic geometric flow. The method and results are computed and written in global tensor form, different from the local normal coordinate method in [DKL1]. In addition, we further show that any solution to the hyperbolic geometric flow that develops a singularity in finite time has unbounded Ricci curvature.Comment: 15 page

    The Properties of H{\alpha} Emission-Line Galaxies at z = 2.24

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    Using deep narrow-band H2S1H_2S1 and KsK_{s}-band imaging data obtained with CFHT/WIRCam, we identify a sample of 56 Hα\alpha emission-line galaxies (ELGs) at z=2.24z=2.24 with the 5σ\sigma depths of H2S1=22.8H_2S1=22.8 and Ks=24.8K_{s}=24.8 (AB) over 383 arcmin2^{2} area in the ECDFS. A detailed analysis is carried out with existing multi-wavelength data in this field. Three of the 56 Hα\alpha ELGs are detected in Chandra 4 Ms X-ray observation and two of them are classified as AGNs. The rest-frame UV and optical morphologies revealed by HST/ACS and WFC3 deep images show that nearly half of the Hα\alpha ELGs are either merging systems or with a close companion, indicating that the merging/interacting processes play a key role in regulating star formation at cosmic epoch z=2-3; About 14% are too faint to be resolved in the rest-frame UV morphology due to high dust extinction. We estimate dust extinction from SEDs. We find that dust extinction is generally correlated with Hα\alpha luminosity and stellar mass (SM). Our results suggest that Hα\alpha ELGs are representative of star-forming galaxies (SFGs). Applying extinction correction for individual objects, we examine the intrinsic Hα\alpha luminosity function (LF) at z=2.24z=2.24, obtaining a best-fit Schechter function characterized by a faint-end slope of α=1.3\alpha=-1.3. This is shallower than the typical slope of α1.6\alpha \sim -1.6 in previous works based on constant extinction correction. We demonstrate that this difference is mainly due to the different extinction corrections. The proper extinction correction is thus key to recovering the intrinsic LF as the extinction globally increases with Hα\alpha luminosity. Moreover, we find that our Hα\alpha LF mirrors the SM function of SFGs at the same cosmic epoch. This finding indeed reflects the tight correlation between SFR and SM for the SFGs, i.e., the so-called main sequence.Comment: 15 pages, 12 figures, 2 tables, Received 2013 October 11; accepted 2014 February 13; published 2014 March 18 by Ap

    Aberrant posterior cingulate connectivity classify first-episode schizophrenia from controls: A machine learning study

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    Background Posterior cingulate cortex (PCC) is a key aspect of the default mode network (DMN). Aberrant PCC functional connectivity (FC) is implicated in schizophrenia, but the potential for PCC related changes as biological classifier of schizophrenia has not yet been evaluated. Methods We conducted a data-driven approach using resting-state functional MRI data to explore differences in PCC-based region- and voxel-wise FC patterns, to distinguish between patients with first-episode schizophrenia (FES) and demographically matched healthy controls (HC). Discriminative PCC FCs were selected via false discovery rate estimation. A gradient boosting classifier was trained and validated based on 100 FES vs. 93 HC. Subsequently, classification models were tested in an independent dataset of 87 FES patients and 80 HC using resting-state data acquired on a different MRI scanner. Results Patients with FES had reduced connectivity between PCC and frontal areas, left parahippocampal regions, left anterior cingulate cortex, and right inferior parietal lobule, but hyperconnectivity with left lateral temporal regions. Predictive voxel-wise clusters were similar to region-wise selected brain areas functionally connected with PCC in relation to discriminating FES from HC subject categories. Region-wise analysis of FCs yielded a relatively high predictive level for schizophrenia, with an average accuracy of 72.28% in the independent samples, while selected voxel-wise connectivity yielded an accuracy of 68.72%. Conclusion FES exhibited a pattern of both increased and decreased PCC-based connectivity, but was related to predominant hypoconnectivity between PCC and brain areas associated with DMN, that may be a useful differential feature revealing underpinnings of neuropathophysiology for schizophrenia

    Effects of mucor mucedo on corncob decomposition in pyr-contaminated soil remediation

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    The effect of polycyclic aromatic hydrocarbon and highly effective degradation fungi Mucor mucedo (MU) was studied on corncob decomposition in Pyr-contaminated soil for 120 days to identify the impact of a degradable immobilized carrier on the remediation of soil contaminated by persistent organic pollutants. Results showed that the corncob was mainly composed of hemicelluloses, cellulose, and water dissolved (WD) material, which accounted for 85 percent of its total weight. MU addition significantly affected corncob decomposition. Thus, humic acid production and WD and benzene-ethanol dissolved material degradation increased. The peaking of the WD content was delayed for 30 days or more. The extractable pyrene content positively correlated with the WD content in the corncob during the decomposition. These results theoretically support a refined remediation principle of immobilized microorganisms

    Intersections of homogeneous Cantor sets and beta-expansions

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    Let Γβ,N\Gamma_{\beta,N} be the NN-part homogeneous Cantor set with β(1/(2N1),1/N)\beta\in(1/(2N-1),1/N). Any string (j)=1N(j_\ell)_{\ell=1}^\N with j{0,±1,...,±(N1)}j_\ell\in\{0,\pm 1,...,\pm(N-1)\} such that t==1Njβ1(1β)/(N1)t=\sum_{\ell=1}^\N j_\ell\beta^{\ell-1}(1-\beta)/(N-1) is called a code of tt. Let Uβ,±N\mathcal{U}_{\beta,\pm N} be the set of t[1,1]t\in[-1,1] having a unique code, and let Sβ,±N\mathcal{S}_{\beta,\pm N} be the set of tUβ,±Nt\in\mathcal{U}_{\beta,\pm N} which make the intersection Γβ,N(Γβ,N+t)\Gamma_{\beta,N}\cap(\Gamma_{\beta,N}+t) a self-similar set. We characterize the set Uβ,±N\mathcal{U}_{\beta,\pm N} in a geometrical and algebraical way, and give a sufficient and necessary condition for tSβ,±Nt\in\mathcal{S}_{\beta,\pm N}. Using techniques from beta-expansions, we show that there is a critical point βc(1/(2N1),1/N)\beta_c\in(1/(2N-1),1/N), which is a transcendental number, such that Uβ,±N\mathcal{U}_{\beta,\pm N} has positive Hausdorff dimension if β(1/(2N1),βc)\beta\in(1/(2N-1),\beta_c), and contains countably infinite many elements if β(βc,1/N)\beta\in(\beta_c,1/N). Moreover, there exists a second critical point αc=[N+1(N1)(N+3)]/2(1/(2N1),βc)\alpha_c=\big[N+1-\sqrt{(N-1)(N+3)}\,\big]/2\in(1/(2N-1),\beta_c) such that Sβ,±N\mathcal{S}_{\beta,\pm N} has positive Hausdorff dimension if β(1/(2N1),αc)\beta\in(1/(2N-1),\alpha_c), and contains countably infinite many elements if β[αc,1/N)\beta\in[\alpha_c,1/N).Comment: 23 pages, 4 figure

    New Results for Diffusion in Lorentz Lattice Gas Cellular Automata

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    New calculations to over ten million time steps have revealed a more complex diffusive behavior than previously reported, of a point particle on a square and triangular lattice randomly occupied by mirror or rotator scatterers. For the square lattice fully occupied by mirrors where extended closed particle orbits occur, anomalous diffusion was still found. However, for a not fully occupied lattice the super diffusion, first noticed by Owczarek and Prellberg for a particular concentration, obtains for all concentrations. For the square lattice occupied by rotators and the triangular lattice occupied by mirrors or rotators, an absence of diffusion (trapping) was found for all concentrations, except on critical lines, where anomalous diffusion (extended closed orbits) occurs and hyperscaling holds for all closed orbits with {\em universal} exponents df=74{\displaystyle{d_f = \frac{7}{4}}} and τ=157{\displaystyle{\tau = \frac{15}{7}}}. Only one point on these critical lines can be related to a corresponding percolation problem. The questions arise therefore whether the other critical points can be mapped onto a new percolation-like problem, and of the dynamical significance of hyperscaling.Comment: 52 pages, including 18 figures on the last 22 pages, email: [email protected]

    Targeted and untargeted metabolomics for the evaluation of plant metabolites in response to the environment - Editorial

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    Over 200 thousand unique metabolites constitute the extremely intricate and diverse plant metabolome (Sousa Silva et al., 2019). Understanding plant growth, development, and responses to environmental perturbations largely rely on the identification and characterization of these diverse metabolites (Allwood et al., 2021
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