Добірка наукової літератури з теми "Muddy plug"

Several specimens of biogenic structures somewhat resembling plug-shaped ichnofossils have been collected in two muddy deposits, Sicilian (Early Pleistocene) in age (Bossio et al., 1987), outcropping near Lecce, southern Apulia, Italy. One sequence is exposed in an unused quarry located at the eastern side of the Cutrofiano–Supersano road, 31 km post; the other one is in an active quarry, southwest of Lecce, near the village of San Pietro in Lama (Figure 1). The diagnostic features of the traces differ from those of the five ichnogenera recognized by Pemberton et al. (1988) for plug-shaped ichnofossils. The minor ichnogenera related to plug-shaped trace fossils, as indicated by those authors, are also different from the present structure. A new ichnogenus is proposed to cover this form.

In this paper, we investigate the dynamics of muddy-seabed motions induced by a surface solitary wave. The muddy seabed is characterized as Bingham-plastic mud. We focus our attention on the situations where the horizontal scale of the wave-induced mud flow is much larger than the vertical scale. The thickness of the mud layer is also assumed to be much smaller than the water depth above. With these simplifications, the dynamic pressure in the mud column remains a constant and the vertical displacement of the water–mud interface is negligible. The horizontal gradient of the wave-induced dynamic pressure along the water–seabed interface drives the motions in the mud bed. For a Bingham-plastic muddy seafloor, the mud moves either like a solid (plug flow) or like a viscous fluid (shear flow) depending on whether the magnitude of shear stress is in excess of the yield stress. Velocities inside these two different flow regimes and the location(s) of the yield surface(s) vary in time as functions of water–mud interfacial pressure gradient and the properties of the Bingham-plastic mud. A semi-analytical approach is developed in this paper to analyse the motions inside the mud bed under a surface solitary wave loading. Three possible scenarios are discussed to illustrate the complexity of the seafloor responses. The formula for the damping rate caused by the energy dissipation inside the muddy seabed is also derived. Using realistic values of the physical parameters, the present results for damping rate agree qualitatively with the available field observations.

Liu & Chan (J. Fluid Mech. vol. 579, 2007, p. 467, hereinafter referred to as LC) derived analytical solutions for the interactions between shallow water waves and a viscous fluid seabed. In this paper we present a set of new experimental data on the solitary-wave-induced flows in a viscous muddy seabed so as to validate LC's theory and the approximations employed. In the experiments a clear silicone fluid was used as the viscous mud and particle image velocimetry was employed to measure the velocity field inside the viscous mud. The shear stress along the bottom of the mud bed and the displacement of the water--mud interface were also deduced from data. Experimental results showed excellent agreement with the theoretical solutions. Additional analyses were performed to show that the ratio of the muddy seabed thickness to the corresponding bottom boundary-layer thickness, $\dbar$, plays an important role in characterizing mud flow regimes. When $\dbar\,{\leq}\,1$, the vertical profile of the horizontal velocity in the mud bed can be parameterized as a parabola. On the other hand, when $\dbar\,{\gg}\,1$, the velocity profile appears as a plug flow above a thin viscous layer. When $ \dbar\,{\sim}\,O(1)$, the flow patterns are more complex than the other two regimes and flow reversal can occur inside the viscous mud bed.

PurposeThis paper seeks to describe the process used to develop the multimedia design and planning pyramid (MUDPY) ontology, and the role played by the MUDPY ontology as a planning, design and development tool in multimedia projects.Design/methodology/approachThe MUDPY model was implemented for the semantic web by developing an ontology for it. This ontology facilitates defining the concepts existing in that domain, their attributes and the relationships between them.FindingsThe MUDPY ontology can guide developers through the various phases of a multimedia project in a systematic fashion by allowing them to create a project proposal, specify the functional requirements, decide on the navigational structure and create a storyboard, and thus create high‐quality projects.Research limitations/implicationsThe current system is a prototype. This MUDPY ontology can be extended by adding more classes in order to increase its functionality; for example, one can develop special plug‐in widgets to generate project reports required during multimedia project planning and design.Practical implicationsBy using the MUDPY ontology, developers can follow a systematic process for project development, and better manage the complexity of multimedia projects.Originality/valueThe paper introduces the MUDPY model and its ontology, and shows a multimedia author the pathway to manage a multitude of concepts and assets required in a multimedia project.

We used a three-dimensional coupled hydrodynamic–ecological model to investigate how lake currents can affect walleye ( Sander vitreus ) recruitment in western Lake Erie. Four years were selected based on a fall recruitment index: two high recruitment years (i.e., 1996 and 1999) and two low recruitment years (i.e., 1995 and 1998). During the low recruitment years, the model predicted that (i) walleye spawning grounds experienced destructive bottom currents capable of dislodging eggs from suitable habitats (reefs) to unsuitable habitats (i.e., muddy bottom), and (ii) the majority of newly hatched larvae were transported away from the known suitable nursery grounds at the start of their first feeding. Conversely, during two high recruitment years, predicted bottom currents at the spawning grounds were relatively weak, and the predicted movement of newly hatched larvae was toward suitable nursery grounds. Thus, low disturbance-based egg mortality and a temporal and spatial match between walleye first feeding larvae and their food resources were predicted for the two high recruitment years, and high egg mortality plus a mismatch of larvae with their food resources was predicted for the two low recruitment years. In general, mild westerly or southwesterly winds during the spawning–nursery period should favour walleye recruitment in the lake.

Depuis les années 1990, le populisme est de retour sur le vieux continent et ailleurs dans le monde. Un de ses foyers se situe en Europe centrale et orientale : c’est ici qu’il atteint aujourd’hui ses formes les plus virulentes, remettant en cause les institutions démocratiques et les libertés individuelles. Depuis quelques années, cette évolution attire l’attention des politistes et plus largement des chercheurs en sciences sociales (Zalewski 2016 ; Potel 2019).Le populisme est souvent considéré comme un concept fourre-tout, un terme valise dont la définition et donc l’usage sont problématiques. Certains le définissent comme une idéologie qui divise la société entre deux camps antagonistes, le « peuple » pur et les « élites » corrompues, et qui place l’intérêt du premier avant toute chose (Mudde & Kaltwasser 2018). Pour d’autres, le populisme est le syndrome d’une crise systémique et d’une volonté d’en sortir (Laclau 2008). Pour d’autres encore, il relève plutôt d’un style politique fondé sur une invocation systématique du « peuple » et empruntant divers éléments aux idéologies de droite comme à celles de gauche (Taguieff 2002, Kaltwasser et al. 2017). En Europe, il fait souvent référence aux mouvements anti-immigration et xénophobes, alors qu’en Amérique latine il renvoie plutôt au clientélisme et à la mauvaise gestion économique des pays.

Kinorhyncha is a phylum of exclusively marine, meiofaunal invertebrates (Sørensen & Pardos 2008). Currently, the knowledge about the worldwide distribution of most of its species is considerably patchy, as several taxa have been reported from a single or few localities, usually within a limited geographic area (Sørensen & Pardos 2008; Yamasaki et al. 2018a). This even becomes more evident for deep-sea kinorhynchs, as noticed by Sørensen et al. (2018). Given the particular value of new records from the deep-sea to increase our understanding in the distribution of meiofaunal organisms plus the observed relationship of morphological variation through the bathymetric gradient, we aim to report the first record of Echinoderes unispinosus Yamasaki, Neuhaus & George, 2018 in the southern edge of the Gulf of Mexico (GoM), and contribute with new information about the morphological intraspecific variation of this species. In Mexico, studies of kinorhynch biodiversity are limited to the northern Gulf of California (50–1570m depth) (Álvarez-Castillo et al. 2015, 2018; Cepeda et al. 2019) and the Yucatán Peninsula (Sánchez & Martínez 2019). The GoM is a semi-closed basin located in a transition zone with both subtropical and tropical weather. Deep-sea muddy sediment samples of the present study were collected during the expedition XIXIMI-5 (10–24 June 2016) and processed according to Cisterna-Céliz et al. (2019). Kinorhynch specimens were mounted, measured and photographed according to Cepeda et al. (2019). Two adult males were identified as E. unispinosus, one from station B11 (2298 m depth) and another from station B15 (3708m depth). Kinorhynch specimens were deposited at the Aquatic Invertebrates Collection of the Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Mexico, under accession numbers: KGM.001 and KGM.002.

Abstract. Resuspension of 137Cs from the contaminated ground surface to the atmosphere is essential for understanding the environmental behaviors of 137Cs and estimating external and inhalation exposure of residents. Kajino et al. (2016) assessed the 137Cs resuspension flux from bare soil and forest ecosystems in eastern Japan in 2013 using a numerical simulation constrained by surface air concentration measurements. However, the simulation was found to underestimate the observed deposition amounts by 2 orders of magnitude. The reason for this underestimation is that the simulation assumed that resuspended 137Cs is carried by submicron aerosols, which have low deposition rates. Based on the observational indications that soil dust and bioaerosols are the major carriers of resuspended 137Cs, a new simulation is performed with higher deposition rates constrained by both surface concentrations and deposition amounts. In the new estimation, the total areal annual resuspension of 137Cs in 2013 is 25.7 TBq, which is equivalent to 0.96 % of the initial deposition (2.68 PBq). Due to the rapid deposition rates, the annual redeposition amount is also large at 10.6 TBq, approximately 40 % of the resuspended 137Cs. The resuspension rate through the atmosphere (0.96 % yr−1) seems slow, but it (2.6 × 10−5 d−1) may not be negligibly small compared to the actual decreasing trend of the ambient gamma dose rate obtained in Fukushima Prefecture after the radioactive decay of 137Cs plus 134Cs in 2013 is subtracted (1.0–7.9 × 10−4 d−1): resuspension can account for 1 %–10 % of the decreasing rate due to decontamination and natural decay through land surface processes. The current simulation underestimated the 137Cs deposition in Fukushima city in winter by more than an order of magnitude, indicating the presence of additional resuspension sources. The site of Fukushima city is surrounded by major roads. Heavy traffic on wet and muddy roads after snow removal operations could generate superlarge (approximately 100 µm in diameter) road dust or road salt particles, which are not included in the model but might contribute to the observed 137Cs at the site.

The recovery rate of a population of feral pigs (Sus scrofa) in the west Kimberley in north-western Australia was determined 12 months after a 1080 (sodium fluoroacetate)-baiting program. An estimated 56 pigs were present in the 15 000-ha study area in August 2005 compared with the prebaiting levels of 250–275 pigs in 2004 (11 pigs were known to be alive on site after the 2004 baiting). This represents a population recovery of 20–23% of the 2004 prebaiting levels. Although most pigs were in good body condition, environmental conditions were quite different between the two years. In 2005, some waterholes were dry or comprised mainly muddy water with little associated shelter for feral pigs. Consequently, and in contrast to 2004, no pigs were seen, and no bait take could be attributed to feral pigs, at the four resurveyed waterholes. Most pig sightings, and activity, were close to the Fitzroy River. Fermented wheat, with blood and bone, was used to determine areas of pig activity, and also used as prefeed before 1080-baiting commenced in 2005. Using the same bait stations as for 2004, plus additional stations established in new areas of pig activity, 1080-treated wheat and malted barley again proved highly effective in reducing pig numbers. The daily sighting index before and after 1080-baiting indicated that pig numbers had been reduced by ~90% within four days. Estimated pre- and postpoisoning density, with and without an edge effect, was 0.12–1.7 pigs km–2 and 0.05–0.67 pigs km–2. Pig tracks decreased to zero on the six track plots within two days of baiting, but the number of macropod tracks remained constant over the four-day baiting period. Thirty-eight poisoned pigs were found after 1080-baiting, and these were generally in clustered groups within 200 m of an active bait station. Poisoned juvenile pigs were again found closer to the active bait stations than were adult or subadult pigs (P < 0.05).

Abstract Background: Oncogenic KRAS is present in almost all cases of pancreatic ductal adenocarcinoma (PDAC). However, targeting KRAS or its canonical signaling cascades, especially the mitogen-activated protein kinase (MAPK) pathway, remains clinically unsuccessful. Targeting ERK kinases has recently emerged as a promising therapeutic strategy and combinatorial strategies should be developed. Aim: Identify adaptive mechanisms to ERK inhibition that can be co-targeted to achieve effective tumor inhibition in multiple patient-derived xenograft (PDX) models. Methods: Reverse-phase protein array (RPPA) was used in early-passage patient-derived cell lines (PDCLs) to identify potential resistance mechanisms. These were confirmed using RNA interference and overexpression in PDAC cell lines and PDCLs. The promising combinations were tested in 30 early-passaged PDAC PDXs. Results: RPPA showed dramatic downregulation of DUSP4 and DUSP6 phosphatases following MEK and ERK inhibition, which coincided with upregulation of phospho-HER2 and -HER3. Knockdown of DUSP6, but not DUSP4, was sufficient in phosphorylation of HER2. Conversely, overexpression of DUSP6 curbed HER2 and ERK activation. Downregulation of DUSP4 and DUSP6 induced by ulixertinib, an ERK inhibitor now in clinical development, was reversed by bortezomib, suggesting DUSP4 and DUSP6 are proteosomally degraded. Combined ulixertinib plus PI3K inhibitor copanlisib, or pan-HER inhibitor afatinib slowed but did not arrest PDX tumor growth in vivo, and addition of gemcitabine was required to achieve tumor regression or durable growth arrest. Alternatively, ulixertinib or MEK inhibitor (trametinib) in combination with trastuzumab deruxtecan (DS-8201a), an anti-HER2 conjugated topoisomerase I inhibitor, were extremely effective, leading to complete and durable tumor regression for all tested PDX models. We showed that upregulation of HER2 expression following MEK or ERK inhibitor treatment provides a conduit for enhanced internalization of DS-8201a. Conclusions: Our study provided novel mechanistic insight on how PDAC cells evade MAPK inhibition via enhancing HER2 signaling. We demonstrated that the combination of MEK or ERK inhibitor plus DS-8201a is extremely effective, leading to complete tumor regression in multiple PDAC PDX models. This combination should be advanced as a clinical trial for PDAC patients. Keys: DS-8201a, DUSP6, HER2, KRAS, ulixertinib, pancreatic ductal adenocarcinoma Citation Format: Ashenafi Shiferaw Bulle, Kuljeet Seehar, Sapana Bansod, Yali Chen, Chen Hung-Po, Paarth B. Dodhiawala, Lin Li, Vikas Somani, Jacqueline Mudd, Ryan C. Fields, Deborah Knoerzer, Andrea Wang-Gillam, Lim Kian-Huat. Pancreatic cancer enhances HER2 signaling through DUSP6 to circumvent therapeutic MAPK inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5333.

L’estuaire du Wouri, situé au coeur du Golfe de Guinée et ouvert sur l’océan Atlantique est soumis à un large éventail d’influence atmosphérique, océanique, continentale et anthropique à différentes échelles de temps (court et long-terme) contrôlant son évolution. La première partie de cette thèse, axée sur des archives remontant au 20ème siècle, a permis de reconstituer l’histoire de l’évolution du littoral estuarien du Wouri. Parallèlement, pour déterminer les tendances d’évolution des hauteurs d’eau, quantifier et qualifier la cinématique du trait de côte et des fonds dans l’estuaire, un travail d’inventaire, de numérisation et d’analyse des documents historiques a été réalisé. Ceci a permis d’enregistrer une évolution du niveau moyen à un rythme d’environ 25mm/an en 17 ans (2002 – 2019). Les résultats ont révélé une prédominance des variations dominées par l’érosion en aval et inversement par l’accrétion en amont, sur la période de 64 ans (1948-2012). Ces tendances sont accentuées par la présence de facteurs amplificateurs (pression anthropique et changement climatique). Afin d’étudier les processus hydrodynamiques et sédimentaires à court terme, une modélisation numérique de la propagation de la marée et la distribution des salinités et des sédiments fins a été réalisée à l’aide de TELEMAC 3D (calibré et validé grâce aux mesures in-situ acquises au cours de l’année 2019). La marée a montré une asymétrie dominée par le jusant dans sa partie inférieure et inversement par le flot dans sa partie supérieure. La distribution de la salinité a permis de caractériser l’estuaire de bien mélangé en vive-eau, particulièrement en étiage à stratifié en morte eau, particulièrement en période de crue. Les variations saisonnières, du régime fluvial ont montré une migration longitudinale de la position de la zone de turbidité maximale : déplacement en amont pendant les étiages et en aval pendant les crues avec pour conséquence une exportation massive de sédiments dans la partie intermédiaire et aval de l’estuaire. Dans un contexte actuel du changement climatique associé aux forts impacts anthropiques, cette étude souligne la nécessité de l’utilisation des archives historiques, de données in-situ couplées à un modèle numérique pour mieux comprendre l’évolution passée et actuelle de l’hydrodynamique et de la dynamique sédimentaire
The Wouri estuary, located in the heart of the Gulf of Guinea and open to the Atlantic Ocean, is subject to a wide range of atmospheric, oceanic, continental and anthropic influences at different time scales (short and long term) controlling its evolution. The first part of this thesis, based on archives dating back to the 20th century, allows us to reconstruct the history of the evolution of the Wouri estuary coastline. At the same time, in order to determine the evolution trends of the water levels, to quantify and qualify the kinematics of the coastline and the bottoms in the estuary, an inventory, digitization and analysis of historical documents was carried out. This allowed to record an evolution of the average level at a rate of about 25mm/year in 17 years (2002 - 2019). The results revealed a predominance of variations dominated by erosion downstream and conversely by accretion upstream, over the 64-year period (1948-2012). These trends are accentuated by the presence of amplifying factors (anthropogenic pressure and climate change). In order to study the hydrodynamic and sedimentary processes in the short term, a numerical modeling of the tidal propagation and the distribution of salinities and fine sediments was performed using TELEMAC 3D (calibrated and validated thanks to in-situ measurements acquired during 2019). The tide showed an asymmetry dominated by the ebb in its lower part and inversely by the flood in its upper part. The distribution of salinity allowed to characterize the estuary from well mixed in spring tide, particularly in low water to stratified in neap tide, particularly in flood period. Seasonal variations of the river regime have shown a longitudinal migration of the position of the maximum turbidity zone : upstream during low water and downstream during high water with a massive export of sediments in the intermediate and downstream part of the estuary. In a current context of climate change associated with strong anthropogenic impacts, this study highlights the need to use historical archives, in-situ data coupled with a numerical model to better understand the past and present evolution of hydrodynamics and sediment dynamics

This chapter reviews the metabolism of homocysteine and its associated defects, focusing on the clinical manifestations of cognitive and behavioral disturbances. The terminology of homocysteine and its derivatives can be confusing, so I begin by clarifying that. Next, the metabolism of homocysteine is outlined, followed by discussion of the disorders of homocysteine transsulfuration. Vitamin B12 (cobalamin, CBL) is important in the effective metabolism of homocysteine and thus defects of CBL absorption, transport, and intracellular transport are also discussed. Finally, disorders of remethylation of methionine will be described. Diagnostic criteria, imaging results, and the pathophysiology of these disorders are also considered. The terminology related to homocysteine metabolism can be confusing. In 2000, a consensus statement on homocysteine nomenclature was published (Mudd et al. 2000). Normal human plasma contains total concentrations of homocysteine and its derivative disulfides of less than 15 μmol/L, although there is some variation due to genetic and other factors. Of this total, only 1%–2% occurs as the thiol (i.e., sulfhydryl) containing amino acid homocysteine. The remaining 98% is in the form of disulfides. Approximately 75%–80% of the total is bound to protein through disulfide bonds with protein cysteines, mainly in albumin, whereas the remainder occurs in non–protein-bound or free forms: the disulfide homocystine-homocystine (Hcy-Hcy), homocysteine-cysteine mixed disulphide, and minor amounts of other mixed disulfides. Together all these moieties make up what is referred to as total homocysteine (tHcy). As all these disulfide bonds can be cleaved by reducing agents, giving the thiol homocysteine, this allows measurement of tHcy as the sum of any thiol homocysteine originally present plus that originally present as a disulfide. In patients with homocystinuria, the percentage contribution of the thiol homocysteine to the total of these forms in plasma rises, reaching 10%–25% as the total homocysteine concentration reaches 150–400 μmol/L. The methionine/homocysteine cycle, also known as the single carbon transfer pathway, is found in all tissues and can broadly be divided into transsulfuration and remethylation components. The cycle aims to conserve methionine and provide sufficient S-adenosylmethionine (AdoMet) for vital transmethylation reactions.