1,191 research outputs found
A general condition of inflationary cosmology on trans-Planckian physics
We consider a more general initial condition satisfying the minimal
uncertainty relationship. We calculate the power spectrum of a simple model in
inflationary cosmology. The results depend on perturbations generated below a
fundamental scale, e.g. the Planck scale.Comment: 7 pages, References adde
Structure of DNA-Functionalized Dendrimer Nanoparticles
Atomistic molecular dynamics simulations have been carried out to reveal the
characteristic features of ethylenediamine (EDA) cored protonated poly amido
amine (PAMAM) dendrimers of generation 3 (G3) and 4 (G4) that are
functionalized with single stranded DNAs (ssDNAs). The four ssDNA strands that
are attached via alkythiolate [-S (CH2)6-] linker molecule to the free amine
groups on the surface of the PAMAM dendrimers observed to undergo a rapid
conformational change during the 25 ns long simulation period. From the RMSD
values of ssDNAs, we find relative stability in the case of purine rich ssDNA
strands than pyrimidine rich ssDNA strands. The degree of wrapping of ssDNA
strands on the dendrimer molecule was found to be influenced by the charge
ratio of DNA and the dendrimer. As G4 dendrimer contains relatively more
positive charge than G3 dendrimer, we observe extensive wrapping of ssDNAs on
the G4 dendrimer. The ssDNA strands along with the linkers are seen to
penetrate the surface of the dendrimer molecule and approach closer to the
center of the dendrimer indicating the soft sphere nature of the dendrimer
molecule. The effective radius of DNA-functionalized dendrimer nanoparticle was
found to be independent of base composition of ssDNAs and was observed to be
around 19.5 {\AA} and 22.4 {\AA} when we used G3 and G4 PAMAM dendrimer as the
core of the nanoparticle respectively. The observed effective radius of
DNA-functionalized dendrimer molecule apparently indicates the significant
shrinkage in the structure that has taken place in dendrimer, linker and DNA
strands. As a whole our results describe the characteristic features of
DNA-functionalized dendrimer nanoparticle and can be used as strong inputs to
design effectively the DNA-dendrimer nanoparticle self-assembly for their
active biological applications.Comment: 13 pages, 10 figures, 3 Table
Energy efficiency of load balancing for data-parallel applications in heterogeneous systems
The use of heterogeneous systems in supercomputing is on the rise
as they improve both performance and energy e ciency. However, the pro-
gramming of these machines requires considerable e ort to get the best results
in massively data-parallel applications. Maat is a library that enables OpenCL
programmers to e ciently execute single data-parallel kernels using all the
available devices on a heterogeneous system. It o ers a set of load balanc-
ing methods, which perform the data partitioning and distribution among the
devices, exploiting more of the performance of the system and consequently re-
ducing execution time. Until now, however, a study of the implications of these
on the energy consumption has not been made. Therefore, this paper analyses
the energy e ciency of the di erent load balancing methods compared to a
baseline system that uses just a single GPU. To evaluate the impact of the
heterogeneity of the system, the GPUs were set to di erent frequencies. The
obtained results show that in all the studied cases there is at least one load
balancing method that improves energy e ciency
Trapped in the prison of the mind: notions of climate-induced (im)mobility decision-making and wellbeing from an urban informal settlement in Bangladesh
The concept of Trapped Populations has until date mainly referred to people ‘trapped’ in environmentally high-risk rural areas due to economic constraints. This article attempts to widen our understanding of the concept by investigating climate-induced socio-psychological immobility and its link to Internally Displaced People’s (IDPs) wellbeing in a slum of Dhaka. People migrated here due to environmental changes back on Bhola Island and named the settlement Bhola Slum after their home. In this way, many found themselves ‘immobile’ after having been mobile—unable to move back home, and unable to move to other parts of Dhaka, Bangladesh, or beyond. The analysis incorporates the emotional and psychosocial aspects of the diverse immobility states. Mind and emotion are vital to better understand people’s (im)mobility decision-making and wellbeing status. The study applies an innovative and interdisciplinary methodological approach combining Q-methodology and discourse analysis (DA). This mixed-method illustrates a replicable approach to capture the complex state of climate-induced (im)mobility and its interlinkages to people’s wellbeing. People reported facing non-economic losses due to the move, such as identity, honour, sense of belonging and mental health. These psychosocial processes helped explain why some people ended up ‘trapped’ or immobile. The psychosocial constraints paralysed them mentally, as well as geographically. More empirical evidence on how climate change influences people’s wellbeing and mental health will be important to provide us with insights in how to best support vulnerable people having faced climatic impacts, and build more sustainable climate policy frameworks
Benzoxazinoids in Root Exudates of Maize Attract Pseudomonas putida to the Rhizosphere
Benzoxazinoids, such as 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), are secondary metabolites in grasses. In addition to their function in plant defence against pests and diseases above-ground, benzoxazinoids (BXs) have also been implicated in defence below-ground, where they can exert allelochemical or antimicrobial activities. We have studied the impact of BXs on the interaction between maize and Pseudomonas putida KT2440, a competitive coloniser of the maize rhizosphere with plant-beneficial traits. Chromatographic analyses revealed that DIMBOA is the main BX compound in root exudates of maize. In vitro analysis of DIMBOA stability indicated that KT2440 tolerance of DIMBOA is based on metabolism-dependent breakdown of this BX compound. Transcriptome analysis of DIMBOA-exposed P. putida identified increased transcription of genes controlling benzoate catabolism and chemotaxis. Chemotaxis assays confirmed motility of P. putida towards DIMBOA. Moreover, colonisation essays in soil with Green Fluorescent Protein (GFP)-expressing P. putida showed that DIMBOA-producing roots of wild-type maize attract significantly higher numbers of P. putida cells than roots of the DIMBOA-deficient bx1 mutant. Our results demonstrate a central role for DIMBOA as a below-ground semiochemical for recruitment of plant-beneficial rhizobacteria during the relatively young and vulnerable growth stages of maize
A multi-disciplinary perspective on emergent and future innovations in peer review [version 1; peer review: 2 approved with reservations]
Peer review of research articles is a core part of our scholarly communication system. In spite of its importance, the status and purpose of peer review is often contested. What is its role in our modern digital research and communications infrastructure? Does it perform to the high standards with which it is generally regarded? Studies of peer review have shown that it is prone to bias and abuse in numerous dimensions, frequently unreliable, and can fail to detect even fraudulent research. With the advent of Web technologies, we are now witnessing a phase of innovation and experimentation in our approaches to peer review. These developments prompted us to examine emerging models of peer review from a range of disciplines and venues, and to ask how they might address some of the issues with our current systems of peer review. We examine the functionality of a range of social Web platforms, and compare these with the traits underlying a viable peer review system: quality control, quantified performance metrics as engagement incentives, and certification and reputation. Ideally, any new systems will demonstrate that they out-perform current models while avoiding as many of the biases of existing systems as possible. We conclude that there is considerable scope for new peer review initiatives to be developed, each with their own potential issues and advantages. We also propose a novel hybrid platform model that, at least partially, resolves many of the technical and social issues associated with peer review, and can potentially disrupt the entire scholarly communication system. Success for any such development relies on reaching a critical threshold of research community engagement with both the process and the platform, and therefore cannot be achieved without a significant change of incentives in research environments
Risk analysis for smart homes and domestic robots using robust shape and physics descriptors, and complex boosting techniques
In this paper, the notion of risk analysis within 3D scenes using vision based techniques is introduced. In particular the problem of risk estimation of indoor environments at the scene and object level is considered, with applications in domestic robots and smart homes. To this end, the proposed Risk Estimation Framework is described, which provides a quantified risk score for a given scene. This methodology is extended with the introduction of a novel robust kernel for 3D shape descriptors such as 3D HOG and SIFT3D, which aims to reduce the effects of outliers in the proposed risk recognition methodology. The Physics Behaviour Feature (PBF) is presented, which uses an object's angular velocity obtained using Newtonian physics simulation as a descriptor. Furthermore, an extension of boosting techniques for learning is suggested in the form of the novel Complex and Hyper-Complex Adaboost, which greatly increase the computation efficiency of the original technique. In order to evaluate the proposed robust descriptors an enriched version of the 3D Risk Scenes (3DRS) dataset with extra objects, scenes and meta-data was utilised. A comparative study was conducted demonstrating that the suggested approach outperforms current state-of-the-art descriptors
MERS-CoV 4b protein interferes with the NF-κB-dependent innate immune response during infection
This work is licensed under a Creative Commons Attribution 4.0 International License.Middle East respiratory syndrome coronavirus (MERS-CoV) is a novel human coronavirus that emerged in 2012, causing severe pneumonia and acute respiratory distress syndrome (ARDS), with a case fatality rate of ~36%. When expressed in isolation, CoV accessory proteins have been shown to interfere with innate antiviral signaling pathways. However, there is limited information on the specific contribution of MERS-CoV accessory protein 4b to the repression of the innate antiviral response in the context of infection. We found that MERS-CoV 4b was required to prevent a robust NF-κB dependent response during infection. In wild-type virus infected cells, 4b localized to the nucleus, while NF-κB was retained in the cytoplasm. In contrast, in the absence of 4b or in the presence of cytoplasmic 4b mutants lacking a nuclear localization signal (NLS), NF-κB was translocated to the nucleus leading to the expression of pro-inflammatory cytokines. This indicates that NF-κB repression required the nuclear import of 4b mediated by a specific NLS. Interestingly, we also found that both in isolation and during infection, 4b interacted with α-karyopherin proteins in an NLS-dependent manner. In particular, 4b had a strong preference for binding karyopherin-α4 (KPNA4), which is known to translocate the NF-κB protein complex into the nucleus. Binding of 4b to KPNA4 during infection inhibited its interaction with NF-κB-p65 subunit. Thereby we propose a model where 4b outcompetes NF-κB for KPNA4 binding and translocation into the nucleus as a mechanism of interference with the NF-κB-mediated innate immune response
Human predecidual stromal cells are mesenchymal stromal/stem cells and have a therapeutic effect in an immune-based mouse model of recurrent spontaneous abortion
Human decidual stromal cells (DSCs) are involved in the maintenance and development of
pregnancy, in which they play a key role in the induction of immunological maternal–fetal tolerance. Precursors of
DSCs (preDSCs) are located around the vessels, and based on their antigen phenotype, previous studies suggested
a relationship between preDSCs and mesenchymal stromal/stem cells (MSCs). This work aimed to further elucidate
the MSC characteristics of preDSCs. Under the effect of P4 and cAMP, the preDSC lines and clones decidualized in vitro: the cells became rounder
and secreted PRL, a marker of physiological decidualization. PreDSC lines and clones also exhibited MSC characteristics.
They differentiated into adipocytes, osteoblasts, and chondrocytes, and preDSC lines expressed stem cell markers OCT-
4, NANOG, and ABCG2; exhibited a cloning efficiency of 4 to 15%; significantly reduced the embryo resorption rate
(P < 0.001) in the mouse model of abortion; and survived for prolonged periods in immunocompetent mice. The fact
that 3 preDSC clones underwent both decidualization and mesenchymal differentiation shows that the same type of
cell exhibited both DSC and MSC characteristics. Together, our results confirm that preDSCs are decidual MSCs and suggest that these cells are involved
in the mechanisms of maternal–fetal immune toleranceThis work was supported by the Plan Estatal de Investigación Científica y
Técnica y de Innovación 2013–2016, ISCIII-Subdirección General de Evaluación y
Fomento de la Investigación, the Ministerio de Economía y Competitividad,
Spain (Grant PI16/01642) and European Regional Development Fund (ERDF/
FEDER funding), the European Community, and the Cátedra de Investigación
Anto nio Chamorro–Alejandro Otero, Universidad de Granada (CACH2017-1)
Proximity assays for sensitive quantification of proteins
Proximity assays are immunohistochemical tools that utilise two or more DNA-tagged aptamers or antibodies binding in close proximity to the same protein or protein complex. Amplification by PCR or isothermal methods and hybridisation of a labelled probe to its DNA target generates a signal that enables sensitive and robust detection of proteins, protein modifications or protein–protein interactions. Assays can be carried out in homogeneous or solid phase formats and in situ assays can visualise single protein molecules or complexes with high spatial accuracy. These properties highlight the potential of proximity assays in research, diagnostic, pharmacological and many other applications that require sensitive, specific and accurate assessments of protein expression
- …