1,985 research outputs found

    Jantzen filtration of Weyl modules, product of Young symmetrizers and denominator of Young's seminormal basis

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    Let GG be a connected reductive algebraic group over an algebraically closed field of characteristic p>0p>0, Δ(λ)\Delta(\lambda) denote the Weyl module of GG of highest weight λ\lambda and ιλ,μ:Δ(λ+μ)Δ(λ)Δ(μ)\iota_{\lambda,\mu}:\Delta(\lambda+\mu)\to \Delta(\lambda)\otimes\Delta(\mu) be the canonical GG-morphism. We study the split condition for ιλ,μ\iota_{\lambda,\mu} over Z(p)\mathbb{Z}_{(p)}, and apply this as an approach to compare the Jantzen filtrations of the Weyl modules Δ(λ)\Delta(\lambda) and Δ(λ+μ)\Delta(\lambda+\mu). In the case when GG is of type AA, we show that the split condition is closely related to the product of certain Young symmetrizers and, under some mild conditions, is further characterized by the denominator of a certain Young's seminormal basis vector. We obtain explicit formulas for the split condition in some cases

    (Orthoptera: Tettigoniidae: Conocephalinae) from Malay Peninsula

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    Allometric effect of body size and tegmen mirror area on sound generator characters in Euconocephalus pallidus (Orthoptera, Tettigoniidae, Copiphorini) from Singapore

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    Acoustic communication, including allometry of secondary sexual traits and body size, can differ among katydid species from different parts of the world. However, Neotropical species tend to be better studied than their Southeast Asian relatives. This is true for the tribe Copiphorini (Orthoptera, Tettigoniidae). To allow for future comparative studies of Neotropical and Palaeotropical Copiphorini, the allometric relationships between sound generator characters and body size of Euconocephalus pallidus from Singapore were examined. Five sound generator characters–tegmen length, stridulatory file length, tooth width, teeth density, and mirror area–were correlated with pronotum length as the proxy for body size. Stridulatory file length, tooth width, and teeth density were also correlated with the mirror area. The relationships were subsequently tested for difference between scaling slope and isometry based on 29 male adults from a single population. All sound generator characters except teeth density exhibited significant positive correlations with pronotum length, whereas teeth density exhibited significant negative correlation with pronotum length. Among them, only tooth width and teeth density scaled hyperallometrically, while the other characters scaled isometrically. As males produce a continuous buzzing call over long durations, larger teeth (i.e., larger tooth width and lower teeth density to accommodate larger teeth) are probably more resistant to age-related abrasion. This may imply that males with larger teeth can produce calls recognized and/or favored by the females over a longer part of the males’ adult lifespan. File length and mirror area exhibited isometric scaling. This suggests a stabilizing selection driven by their function in dictating carrier frequency, which females tend to rely on to recognize conspecific males

    Preliminary study on the diversity of Orthoptera from Kuala Belalong Field Studies Centre, Brunei Darussalam, Borneo

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    The Orthoptera, comprising grasshoppers, crickets, and katydids, is diverse and species rich in tropical Southeast Asia, including the island of Borneo. However, not every part of Southeast Asia is equally well sampled and studied. This includes Brunei Darussalam, specifically at the Kuala Belalong Field Studies Centre (KBFSC) within the Ulu Temburong National Park. We present here an annotated and illustrated checklist of Orthoptera from the primary dipterocarp forest around Kuala Belalong based on three field trips in 2016 and 2017. We provide notes on their taxonomy (including how each species was identified) and natural history of species. In total, 72 species were recorded, representing eight of the 16 monophyletic orthopteran superfamilies. In total, 73.6% of all species recorded were singletons and doubletons, indicating that many species are probably rare. The collection led to the discovery of ten species new to science already published separately, with more expected to be described from pending material and confirmation. More species, including undescribed ones (at least four new species), are expected with continued sampling effort. Despite the 21 day-long surveying efforts from three trips around KBFSC, we believe that the species list provided here is non-exhaustive and only a preliminary one

    Development of a palm olein oil-in-water (o/w) emulsion stabilized by a whey protein isolate nanofibrils-alginate complex

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    An oil-in-water (o/w) emulsion is a system where the oil droplets are dispersed within a watery phase. The most important function of emulsions is their ability to incorporate lipophilic components into food matrices. Thus, it is crucial to develop an emulsion that is highly stable. This work was aimed at developing a palm olein o/w emulsion stabilized by a whey protein isolate nanofibrils-alginate complex, as well as evaluating the influence of oil load and the homogenization process (both pressure and cycle) on the characteristics of the o/w emulsions. Emulsions were analyzed for droplet size, zeta potential, viscosity, creaming stability, and morphology. The results showed that an increase in oil load led to a larger droplet size, less negative zeta potential, and emulsions that were more viscous and less stable. On the other hand, increasing homogenization pressure and the number of homogenization cycles resulted in a smaller droplet size, more negative zeta potential, and emulsions that were less viscous and more stable. Emulsions with a smaller droplet size and better stability resulted from lower oil load, high homogenization pressure and more homogenization cycles

    Case report: A giant hemorrhagic adrenocortical carcinoma causing cardiorespiratory embarrassment

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    Adrenocortical carcinoma (ACC) is a rare aggressive tumor that can be hormone or non-hormone secreting. It is usually associated with fatal outcomes due to its physiological hormonal interaction. We report a successful anaesthetic and surgical management for a patient who presented to us with a huge hemorrhagic ACC which was complicated with acute respiratory failure. A 56-year-old lady presented to us with progressive abdominal distension and right hypochondriac pain for two months. She was anemic with elevated liver enzymes. Urgent computed tomography (CT) of the abdomen and pelvis showed a huge right supra renal mass. She subsequently developed respiratory failure due to splinting of diaphragm, of which successfully underwent an emergency exploratory laparotomy. Subsequent endocrine and histopathological work up showed an adrenocortical carcinoma (ACC). Suprarenal masses usually originate from the adrenal glands. They should be investigated to rule out phaeochromocytoma, which originate from the inner adrenal medulla or outer cortex to form ACC. The latter usually occur in women and of poor prognosis. Huge ACC may cause acute respiratory failure by way of splinting of diaphragm. Both anaesthetic and surgical teams should be well trained in handling patients who undergo adrenal surgeries. A giant hemorrhagic functional ACC is extremely uncommon with very poor prognosis. Such conditions should be investigated to rule out phaeochromocytoma. Its potential neuro-hormonal interactions and anatomical correlations can cause fatal perioperative cardio-respiratory embarrassment. The anaesthetic and surgical teams should be capable in managing the hemodynamic instabilities that may present during surgical manipulation and resection of a large ACC

    Wip1-dependent modulation of macrophage migration and phagocytosis

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    Macrophage accumulation within the vascular wall is a hallmark of atherosclerosis. Controlling macrophage conversion into foam cells remains a major challenge for treatment of atherosclerotic diseases. Here, we show that Wip1, a member of the PP2C family of Ser/Thr protein phosphatases, modulates macrophage migration and phagocytosis associated with atherosclerotic plaque formation. Wip1 deficiency increases migratory and phagocytic activities of the macrophage under stress conditions. Enhanced migration of Wip1-/- macrophages is mediated by Rac1-GTPase and PI3K/AKT signalling pathways. Elevated phagocytic ability of Wip1-/- macrophages is linked to CD36 plasma membrane recruitment that is regulated by AMPK activity. Our study identifies Wip1 as an intrinsic negative regulator of macrophage chemotaxis. We propose that Wip1-dependent control of macrophage function may provide avenues for preventing or eliminating plaque formation in atherosclerosis

    The Mesozoic magmatic, metamorphic, and tectonic evolution of the eastern Gangdese magmatic arc, southern Tibet

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    Magmatic arcs are natural laboratories for studying the growth of continental crusts. The Gangdese arc, southern Tibet, is an archetypal continental magmatic arc that formed due to Mesozoic subduction of the Neo-Tethyan oceanic lithosphere; however, its formation and evolution remain controversial. In this contribution, we combine newly reported and previously published geochemical and geochronological data for Mesozoic magmatic rocks in the eastern Gangdese arc to reveal its magmatic and metamorphic histories and review its growth, thickening, and fractionation and mineralization processes. Our results show that: (1) the Gangdese arc consists of multiple Mesozoic arc-type magmatic rocks and records voluminous juvenile crustal growth. (2) The Mesozoic magmatic rocks experienced Late Cretaceous granulite-facies metamorphism and partial melting, thus producing hydrous and metallogenic element-rich migmatites that form a major component of the lower arc crust and are a potential source for the Miocene ore-hosting porphyries. (3) The Gangdese arc witnessed crustal thickening and reworking during the Middle to Late Jurassic and Late Cretaceous. (4) Crystallization-fractionation of mantle-derived magmas and partial melting of thickened juvenile lower crust induced intracrustal chemical differentiation during subduction. We suggest that the Gangdese arc underwent the following main tectonic, magmatic, and metamorphic evolution processes: normal subduction and associated mantle-derived magmatism during the Late Triassic to Jurassic; shallow subduction during the Early Cretaceous and an associated magmatic lull; and mid-oceanic ridge subduction, high-temperature metamorphism and an associated magmatic flare-up during the early Late Cretaceous, and flat subduction, high-temperature and high-pressure metamorphism, partial melting, and associated crust-derived magmatism during the late Late Cretaceous. Key issues for further research include the temporal and spatial distributions of Mesozoic magmatic rocks, the evolution of the components and compositions of arc crust over time, and the metallogenic processes that occur in such environments during subduction

    Jejunojejunal intussusception secondary to inflammatory fibroid polyp: A rare cause of small bowel obstruction

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    Background: Adult intussusception is a relatively rare clinical entity. The majority of cases of intussusception in adults are due to a pathologic condition that serves as a lead point and requires surgery. Small bowel intussusception is usually caused by benign or malignant neoplasms appearing at the head of the invagination. Inflammatory fibroid polyp (IFP) of the small bowel is an unusual benign neoplastic lesion that has been rarely reported to cause intussusception, especially in the jejunum. Case presentation: We present a rare case of adult intussusception who presented with a triad of intestinal obstruction. Computed tomography revealed small bowel intussusception with bowel ischemia. Intraoperatively, she required resection of the small bowel and primary anastomosis. Macroscopic examination revealed a single pedunculated polyp, which is the lead point of intestinal obstruction and confirmed histologically. Conclusion: Inflammatory fibroid polyp should be considered as a cause of intussusception among adults with small bowel obstruction
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