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
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
We consider the hyperbolic geometric flow 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
Using deep narrow-band and -band imaging data obtained with
CFHT/WIRCam, we identify a sample of 56 H emission-line galaxies (ELGs)
at with the 5 depths of and (AB)
over 383 arcmin area in the ECDFS. A detailed analysis is carried out
with existing multi-wavelength data in this field. Three of the 56 H
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 H 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 H luminosity
and stellar mass (SM). Our results suggest that H ELGs are
representative of star-forming galaxies (SFGs). Applying extinction correction
for individual objects, we examine the intrinsic H luminosity function
(LF) at , obtaining a best-fit Schechter function characterized by a
faint-end slope of . This is shallower than the typical slope of
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 H luminosity.
Moreover, we find that our H 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
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
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
Let be the -part homogeneous Cantor set with
. Any string with
such that is called a code of . Let
be the set of having a unique code,
and let be the set of which make the intersection a
self-similar set. We characterize the set in a
geometrical and algebraical way, and give a sufficient and necessary condition
for . Using techniques from beta-expansions, we
show that there is a critical point , which is a
transcendental number, such that has positive
Hausdorff dimension if , and contains countably
infinite many elements if . Moreover, there exists a
second critical point
such that
has positive Hausdorff dimension if
, and contains countably infinite many elements if
.Comment: 23 pages, 4 figure
New Results for Diffusion in Lorentz Lattice Gas Cellular Automata
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 and . 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
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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