11,204 research outputs found
Predicting and understanding spatio-temporal dynamics of species recovery : implications for Asian crested ibis Nipponia nippon conservation in China
Acknowledgements This work was supported by the National Natural Science Foundation of China (No. 31372218) and cofunded by the China Scholarship Council (CSC) and the ITC Research Fund, Enschede, the Netherlands. We thank Shaanxi Hanzhong Crested Ibis National Nature Reserve for sharing the data of nest site locations. We are grateful to Brendan Wintle, Justin Travis and two anonymous reviewers for helpful comments on a previous version of the manuscript.Peer reviewedPublisher PD
Algebraic structures for adjoint-symmetries and symmetries of partial differential equations
Symmetries of a partial differential equation (PDE) can be defined as the
solutions of the linearization (Frechet derivative) equation holding on the
space of solutions to the PDE, and they are well-known to comprise a linear
space having the structure of a Lie algebra. Solutions of the adjoint
linearization equation holding on the space of solutions to the PDE are called
adjoint-symmetries. Their algebraic structure for general PDE systems is
studied herein. This is motivated by the correspondence between variational
symmetries and conservation laws arising from Noether's theorem, which has a
well-known generalization to non-variational PDEs, where symmetries are
replaced by adjoint-symmetries, and variational symmetries are replaced by
multipliers (adjoint-symmetries satisfying a certain Euler-Lagrange condition).
Several main results are obtained. Symmetries are shown to have three different
linear actions on the linear space of adjoint-symmetries. These linear actions
are used to construct bilinear adjoint-symmetry brackets, one of which is like
a pull-back of the symmetry commutator bracket and has the properties of a Lie
bracket. In the case of variational PDEs, adjoint-symmetries coincide with
symmetries, and the linear actions themselves constitute new bilinear symmetry
brackets which differ from the commutator bracket when acting on
non-variational symmetries. Several examples of nonlinear PDEs are used to
illustrate all of the results.Comment: 32 pages; minor change
Endorepellin remodels the endothelial transcriptome toward a pro-autophagic and pro-mitophagic gene signature.
Regulation of autophagy by proteolytically cleaved fragments of heparan sulfate proteoglycans is a novel and current research focus in tumor biology. Endorepellin is the C-terminal angiostatic fragment of the heparan sulfate proteoglycan perlecan and induces autophagy in endothelial cells. To further investigate this property, we used NanoString, a digital PCR platform for measuring pre-defined transcripts in biological samples to analyze a custom subset of 95 autophagy-related genes in human umbilical vein endothelial cells treated with ultrapure human recombinant endorepellin. We discovered an endorepellin-evoked pro-autophagic and pro-mitophagic gene expression signatures, which included two coordinately up-regulated mitochondrial-associated genes encoding the E3 ubiquitin protein ligase Parkin and the tumor suppressor mitostatin. Induction of both proteins required the tyrosine kinase activity of vascular endothelial growth factor receptor 2 (VEGFR2). Furthermore, we discovered that endorepellin evoked mitochondrial depolarization in endothelial cells via a specific interaction between its two proximal LG1/2 domains and VEGFR2. We also found that following loss of membrane potential, mitostatin and parkin interact and that mitostatin associates with the established Parkin receptor mitofusin-2. In conclusion, we have identified a critical role for endorepellin in remodeling the autophagic transcriptome and influencing mitochondrial homeostasis
A new record of Percursaria percursa (Ulvaceae, Ulvales) on the North Island, New Zealand
The filamentous green alga Percursaria percursa (Ulvaceae, Ulvales) was recorded for the first time on the North Island of New Zealand at mokoroa Estuary, Tauranga Harbour. This species is previously known within New Zealand from only two records, both from the South Island. In Tauranga Harbour, this species was restricted to anoxic estuarine sediments where mangrove forests had been mulched, and mulchate left in situ. Percursaria percursa was found intertwined with Ulva spp. and Rhizoclonium spp. Surveys of other North and South Island estuaries suggest that this alga, although occurring as part of nuisance green algal blooms in Tauranga Harbour, has only colonized human-impacted locations, and has not yet been observed in natural' estuarine ecosystems in New Zealand. As this species was found intertwined with other mat-forming filamentous green algae, it can easily be misidentified in the field, leading to both over- and under-reporting of species occurrence
Multi-Item Single-Vendor-Single-Buyer Problem with Consideration of Transportation Quantity Discount
This paper deals with the problem of shipping multiple commodities from a single vendor to a single buyer. Each commodity is assumed to be constantly consumed at the buyer, and periodically replenished from the vendor. Furthermore, these replenishments are restricted to happen at discrete time instants, e.g., a certain time of the day or a certain day of the week. At any such time instant, transportation cost depends on the shipment quantity according to certain discount scheme. Specifically, we consider two transportation quantity discount schemes: LTL (less-than-truckload) incremental discount and TL (truckload) discount. For each case, we develop MIP (mixed integer programming) mathematical model whose objective is to make an integrated replenishment and transportation decision such that the total system cost is minimized. We also derive optimal solution properties and give numerical studies to investigate the problem.Singapore-MIT Alliance (SMA
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