2,053 research outputs found

    Indicators of land use by cattle: Associations among methods and role of environmental factors

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    The objectives of this study were to investigate the associations among direct and indirect indicators of land use by cattle and to understand the role of some environmental factors on the definition of these indicators. The study was carried out in two areas, Nature Reserve (63.6 ha) and Private Area (30.4 ha), with 53 Hereford animals in each area. Daytime observations of animals’ location were used as direct indicator of land use; while cattle track and dung pat distributions throughout the areas were used as indirect indicators. Environmental characteristics recorded were: terrain slope, prevalence of woody vegetation cover (forests, isolated tress and open grasslands), as well as the position of fences, water sources and salt blocks. Spatial correlations among the three indicators of land use were low (r < 0.30). The environmental factors had lower predictive power of animals’ sightings distribution, followed by cattle tracks, and the highest predictive power occurred for dung pat distribution. We concluded that each one of the methods evaluated in this study addresses a different aspect of land use by cattle. The environmental factors assessed were useful to predict the dung pat distribution, but less valuable to predict the cattle tracks and animals’ sightings distributions

    How antagonistic salts cause nematic ordering and behave like diblock copolymers

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    We present simulation results and an explanatory theory on how antagonistic salts affect the spinodal decomposition of binary fluid mixtures. We find that spinodal decomposition is arrested and complex structures form only when electrostatic ion-ion interactions are small. In this case fluid and ion concentrations couple and the charge field can be approximated as a polynomial function of the relative fluid concentrations alone. When the solvation energy associated with transfering an ion from one fluid phase to the other is of the order of a few k_BT, the coupled fluid and charge fields evolve according to the Ohta-Kawasaki free energy functional. This allows us to accurately predict structure sizes and reduce the parameter space to two dimensionless numbers. The lamellar structures induced by the presence of antagonistic salt in our simulations exhibit a high degree of nematic ordering and the growth of ordered domains over time seems to follow a power law. This power law carries a time exponent proportional to the salt concentration. We reproduce and interpret neutron scattering data from previous experiments of similar systems. The dissolution of structures at high salt concentrations observed in these experiments agrees with our simulations and we explain it as the result of a vanishing surface tension due to electrostatic contributions. We conclude by presenting preliminary 3D results showing the same morphologies as predicted by the Ohta-Kawasaki model as a function of volume fraction and suggesting that our findings from 2D systems remain valid in 3D.Comment: 13 pages, 7 figure

    A beta-herpesvirus with fluorescent capsids to study transport in living cells.

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    Fluorescent tagging of viral particles by genetic means enables the study of virus dynamics in living cells. However, the study of beta-herpesvirus entry and morphogenesis by this method is currently limited. This is due to the lack of replication competent, capsid-tagged fluorescent viruses. Here, we report on viable recombinant MCMVs carrying ectopic insertions of the small capsid protein (SCP) fused to fluorescent proteins (FPs). The FPs were inserted into an internal position which allowed the production of viable, fluorescently labeled cytomegaloviruses, which replicated with wild type kinetics in cell culture. Fluorescent particles were readily detectable by several methods. Moreover, in a spread assay, labeled capsids accumulated around the nucleus of the newly infected cells without any detectable viral gene expression suggesting normal entry and particle trafficking. These recombinants were used to record particle dynamics by live-cell microscopy during MCMV egress with high spatial as well as temporal resolution. From the resulting tracks we obtained not only mean track velocities but also their mean square displacements and diffusion coefficients. With this key information, we were able to describe particle behavior at high detail and discriminate between particle tracks exhibiting directed movement and tracks in which particles exhibited free or anomalous diffusion

    Overlay Accuracy Limitations of Soft Stamp UV Nanoimprint Lithography and Circumvention Strategies for Device Applications

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    In this work multilevel pattering capabilities of Substrate Conformal Imprint Lithography (SCIL) have been explored. A mix & match approach combining the high throughput of nanoimprint lithography with the excellent overlay accuracy of electron beam lithography (EBL) has been exploited to fabricate nanoscale devices. An EBL system has also been utilized as a benchmarking tool to measure both stamp distortions and alignment precision of this mix & match approach. By aligning the EBL system to 20 mm x 20 mm and 8 mm x 8 mm cells to compensate pattern distortions of order of 3ÎĽm3 \mu m over 6 inch wafer area, overlay accuracy better than 1.2ÎĽm1.2 \mu m has been demonstrated. This result can partially be attributed to the flexible SCIL stamp which compensates deformations caused by the presence of particles which would otherwise significantly reduce the alignment precision

    Autoimmune Myasthenia Gravis after Sternal Fracture

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    We report a 54-year-old woman who suffered a commotio cerebri, whiplash injury and a chest trauma with sternal fracture due to a high-velocity car accident. Two months later, she developed unilateral ptosis and blurred vision, which worsened during the day. Multiple diagnoses were suggested, ranging from thoracic outlet syndrome towards depression. Symptoms persisted and five years later, the patient consulted a neurologist. Laboratory analysis revealed significantly elevated levels of antibodies to acetylcholine receptors, and the diagnosis of myasthenia gravis was made. Speculatively, the damage of retrosternal thymic remnants due to a sternal fracture might have precipitated the condition or exacerbated subclinical disease

    Mixed large cell neuroendocrine carcinoma and squamous cell carcinoma of the colon: detailed molecular characterisation of two cases indicates a distinct colorectal cancer entity

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    We present two rare cases of mixed large cell neuroendocrine carcinoma and squamous cell carcinoma of the colon. A literature search revealed only three published cases with similar histology but none of these reports provided profound molecular and mutational analyses. Our two cases exhibited a distinct, colon-like immunophenotype with strong nuclear CDX2 and beta-catenin expression in more than 90% of the tumour cells of both components. We analysed the two carcinomas regarding microsatellite stability, RAS, BRAF and PD-L1 status. In addition, next-generation panel sequencing with Ion AmpliSe (TM) psi Cancer Hotspot Panel v2 was performed. This approach revealed mutations in FBXW7, CTNNB1 and PIK3CA in the first case and FBXW7 and RB1 mutations in the second case. We looked for similar mutational patterns in three publicly available colorectal adenocarcinoma data sets, as well as in collections of colorectal mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) and colorectal neuroendocrine carcinomas. This approach indicated that the FBXW7 point mutation, without being accompanied by classical adenoma-carcinoma sequence mutations, such as APC, KRAS and TP53, likely occurs at a relatively high frequency in mixed neuroendocrine and squamous cell carcinoma and therefore may be characteristic for this rare tumour type. FBXW7 codifies the substrate recognition element of an ubiquitin ligase, and inactivating FBXW7 mutations lead to an exceptional accumulation of its target beta-catenin which results in overactivation of the Wnt-signalling pathway. In line with previously described hypotheses of de-differentiation of colon cells by enhanced Wnt-signalling, our data indicate a crucial role for mutant FBXW7 in the unusual morphological switch that determines these rare neoplasms. Therefore, mixed large cell neuroendocrine and a squamous cell carcinoma can be considered as a distinct carcinoma entity in the colon, defined by morphology, immunophenotype and distinct molecular genetic alteration(s)
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