In the dipteran Drosophila, the genes bicoid and hunchback work synergistically to pattern the anterior blastoderm during embryogenesis. bicoid, however, appears to be an innovation of the higher ...Diptera. Hence, in some non-dipteran insects, anterior specification instead relies on a synergistic interaction between maternally transcribed hunchback and orthodenticle. Here we describe how orthologues of hunchback and orthodenticle are expressed during oogenesis and embryogenesis in the parthenogenetic and viviparous form of the pea aphid, Acyrthosiphon pisum. A. pisum hunchback (Aphb) mRNA is localized to the anterior pole in developing oocytes and early embryos prior to blastoderm formation - a pattern strongly reminiscent of bicoid localization in Drosophila. A. pisum orthodenticle (Apotd), on the other hand, is not expressed prior to gastrulation, suggesting that it is the asymmetric localization of Aphb, rather than synergy between Aphb and Apotd, that regulates anterior specification in asexual pea aphids.
The increasing volume of scientific publications has created a need for more efficient and effective literature review processes. Bibliometric analysis is a quantitative approach to analysing ...bibliographic data extracted from research studies to identify publishing patterns and trends within specific knowledge domains. Science mapping is a widespread technique in bibliometric analysis that enables researchers to reveal the structure of their respective fields and identify dominant themes. However, there is still a lack of clarity and transparency in describing the science mapping process, which can hinder continued refinement and improvement of this critical field of research. This study provides a comprehensive overview of science mapping in bibliometric analysis based on published review studies from prestigious international journals. It outlines the science mapping mechanism and explores challenges and opportunities, focusing on incorporating text mining approaches to support the analytical literature review process. The study sheds light on previously unexplored mechanisms in the literature of bibliometric analysis, revealing gaps in existing research. The study contributes to the growing body of research on bibliometric analysis by highlighting the need for continuous improvement and the deployment of text mining techniques to support the analysis of scientific publication data. This study offers valuable insights for researchers, policymakers, and practitioners seeking to enhance their understanding of science mapping and bibliometric analysis.
In this paper, the radiation and scattering problems with circular boundaries are studied by using the null-field integral equations in conjunction with degenerate kernels and Fourier series to avoid ...calculating the Cauchy and Hadamard principal values. In implementation, the null-field point can be located on the real boundary owing to the introduction of degenerate kernels for fundamental solution. An adaptive observer system of polar coordinate is considered to fully employ the property of degenerate kernels. For the hypersingular equation, vector decomposition for the radial and tangential gradient is carefully considered. This method can be seen as a semi-analytical approach since errors attribute from the truncation of Fourier series. Neither hypersingularity in Burton and Miller approach nor the CHIEF concepts were required to deal with the problem of irregular frequencies. Four gains, well-posed model, singularity free, boundary-layer effect free and exponential convergence are achieved by using the present approach. A fast convergence rate in exponential order than algebraic one in BEM stems from the series expansions. Three examples were demonstrated to see the validity of the present formulation and show the better accuracy than BEM.
In order to assess the left ventricular (LV) longitudinal rotation (LR) in primary hypertension (PH) patients with a normal LV ejection fraction. Conventional echocardiography was performed in 61 ...healthy subjects and 64 PH patients. The apical four-chamber views in these patients were acquired by GE-Vivid7 or E9, then the peak radial strain in the systolic period and the strain rate in systole, in early and late diastolic periods, were measured. Segmental LR and global LR were assessed by using two-dimensional speckle tracking imaging (2D-STI). The peak radial strain rate in the early diastolic period in PH patients was significantly lower than that in healthy subjects. The rotational degrees of the middle and base lateral, the apex and the middle septum walls in PH patients were significantly different from those of the healthy subjects. The healthy subjects had prominent counter-clockwise LR (0.29°±2.86°) and the PH patients had prominent clockwise LR (-2.13°±2.93°) in non-LV wall hypertrophy and (-2.43°±2.66°) in LV wall hypertrophy. The time delay between the LV lateral wall and the septum wall in PH patients correlated to the peak LR. We concluded that 2D-STI can assess the time delay between the LV lateral wall and the septum wall to the peak LR and clockwise LR in patients with PH, and prove that PH patients have a clockwise LR. By this, we conclude that in PH patients, the LV early systolic function have changed.
Carotid-femoral pulse wave velocity (cf-PWV) is a validated marker of arterial stiffening over the central arteries. Brachial-ankle pulse wave velocity (ba-PWV) integrates the mechanical properties ...from both the central and peripheral arteries and may be more representative than cf-PWV as arterial load for left ventricle (LV). We compared ba-PWV with cf-PWV for the association of cardiovascular structure and function in 320 subjects with various degrees of abnormality in cardiac structure and function. ba-PWV (by oscillometric technique) and cf-PWV (by tonometric technique) were measured simultaneously, and were highly correlated (r=0.79, P<0.001). Both ba-PWV and cf-PWV were significantly correlated with LV mass, but the correlation was better with ba-PWV (r=0.29 vs r=0.22, P=0.0219). While ba-PWV and cf-PWV were similarly significantly correlated with LV end-systolic elastance and mitral E/A ratio, ba-PWV had better correlation with isovolumic relaxation constant (r=0.34 vs r=0.27, P=0.0202) than cf-PWV. In addition, the correlation was also significantly stronger with ba-PWV than with cf-PWV for other indices of arterial stiffness, including carotid incremental modulus (r=0.59 vs 0.50, P=0.0013), effective arterial elastance (r=0.41 vs r=0.33, P=0.0081) and carotid augmentation index (r=0.38 vs r=0.32, P=0.0368). In conclusion, ba-PWV correlates better with LV mass and diastolic function and other indices of arterial function than cf-PWV, probably because ba-PWV encompasses a greater territory of arterial tree than cf-PWV.
Crossings and nestings of matchings and partitions Chen, William Y. C.; Deng, Eva Y. P.; Du, Rosena R. X. ...
Transactions of the American Mathematical Society,
04/2007, Letnik:
359, Številka:
4
Journal Article
Recenzirano
Odprti dostop
We present results on the enumeration of crossings and nestings for matchings and set partitions. Using a bijection between partitions and vacillating tableaux, we show that if we fix the sets of ...minimal block elements and maximal block elements, the crossing number and the nesting number of partitions have a symmetric joint distribution. It follows that the crossing numbers and the nesting numbers are distributed symmetrically over all partitions of n, as well as over all matchings on 2n. As a corollary, the number of k-noncrossing partitions is equal to the number of k-nonnesting partitions. The same is also true for matchings. An application is given to the enumeration of matchings with no k-crossing (or with no k-nesting).
ABSTRACT
Cir X-1 is an unusual X-ray binary, which has resumed periodic outbursts since August 2019. We investigate the post-quiescence spectral properties of Cir X-1 at orbital phase around the ...periastron using NICER and NuSTAR X-ray observatories after the resumption of outbursts. We identify two distinct classes of spectral properties. The first class exhibits highly ionized absorption, whereas the second class does not. We suggest that the ionized absorption originates from the shelter of the disc wind, while the low-ionized/neutral absorption arises from the companion’s stellar wind. We also suggest that the disc wind may be always present in both classes, and a warped precession disc could alter the visibility of the disc wind.
Transplantation of peripheral nervous system glia is being explored for treating neural injuries, in particular central nervous system injuries. These glia, olfactory ensheathing cells (OECs) and ...Schwann cells (SCs), are thought to aid regeneration by clearing necrotic cells, (necrotic bodies, NBs), as well as myelin debris. The mechanism by which the glia phagocytose and traffic NBs are not understood. Here, we show that OECs and SCs recognize phosphatidylserine on NBs, followed by engulfment and trafficking to endosomes and lysosomes. We also showed that both glia can phagocytose and process myelin debris. We compared the time-course of glial phagocytosis (of both NBs and myelin) to that of macrophages. Internalization and trafficking were considerably slower in glia than in macrophages, and OECs were more efficient phagocytes than SCs. The two glial types also differed regarding their cytokine responses after NB challenge. SCs produced low amounts of the pro-inflammatory cytokine TNF-α while OECs did not produce detectable TNF-α. Thus, OECs have a higher capacity than SCs for phagocytosis and trafficking, whilst producing lower amounts of pro-inflammatory cytokines. These findings suggest that OEC transplantation into the injured nervous system may lead to better outcomes than SC transplantation.
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