920 research outputs found

    Remarks on the quasi-position representation in models of generalized uncertainty principle

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    This note aims to elucidate certain aspects of the quasi-position representation frequently used in the investigation of one-dimensional models based on the generalized uncertainty principle (GUP). We specifically focus on two key points: (i) Contrary to recent claims, the quasi-position operator can possess physical significance even though it is non-Hermitian, and (ii) in the quasi-position representation, operators associated with the position, such as the potential energy, also behave as a derivative operator on the quasi-position coordinate, unless the method of computing expectation values is modified. The development of both points revolves around the observation that the position and quasi-position operators share the same set of eigenvalues and are connected through a non-unitary canonical transformation. This outcome may have implications for widely referenced constraints on GUP parameters

    Reconfigurable Intelligent Surfaces: The New Frontier of Next G Security

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    RIS is one of the significant technological advancements that will mark next-generation wireless. RIS technology also opens up the possibility of new security threats, since the reflection of impinging signals can be used for malicious purposes. This article introduces the basic concept for a RIS-assisted attack that re-uses the legitimate signal towards a malicious objective. Specific attacks are identified from this base scenario, and the RIS-assisted signal cancellation attack is selected for evaluation as an attack that inherently exploits RIS capabilities. The key takeaway from the evaluation is that an effective attack requires accurate channel information, a RIS deployed in a favorable location (from the point of view of the attacker), and it disproportionately affects legitimate links that already suffer from reduced path loss. These observations motivate specific security solutions and recommendations for future work.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

    On the performance of the intermediate Hamiltonian Fock-space coupled-cluster method on linear triatomic molecules: The electronic spectra of NpO2+, NpO22+, and Pu O22

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    International audienceIn this paper we explore the use of the novel relativistic intermediate Hamiltonian Fock-space coupled-cluster method in the calculation of the electronic spectrum for small actinyl ions (NpO2+, NpO22+, and PuO22+). It is established that the method, in combination with uncontracted double-zeta quality basis sets, yields excitation energies in good agreement with experimental values, and better than those obtained previously with other theoretical methods. We propose the reassignment of some of the peaks that were observed experimentally, and confirm other assignments

    Trailing Boom on Fungicides Application on Wheat, Bean and Soybean

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    This study aimed to determine the influence of air-assisted and trailing boom technologies on fungicide applications to control diseases incidence and severity on wheat, bean and soybean. The experiments were conducted in three different sites in the Campos Gerais (PR) region in a completely randomized blocks design. In the wheat crop season of 2011, the treatments were: i) control (no fungicide application on the plants); fungicide spray with ii) nozzles in conventional ground boom sprayer; iii) nozzles in trailing boom; and iv) nozzles in conventional boom sprayer + trailing boom simultaneously. In the bean and soybean crop season of 2011-12, we added an extra treatment of boom with air-assisted sprayer, since the farmers had this technology available. We conclude that at the area under the disease progress curve (AUDPC), the diseases controlled with fungicides presented lower severity and incidence compared with the control treatment for all the crops evaluated. The fungicide spraying technology aggregated to air-assisted and trailing boom did not differ from the conventional boom sprayer for disease control and yield components of wheat, beans and soybeans

    Aberrant MEK5/ERK5 signalling contributes to human colon cancer progression via NF-ÎşB activation

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    © 2015 Macmillan Publishers Limited All rights reserved. Cell Death and Disease is an open-access journal published by Nature Publishing Group. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0This study was designed to evaluate MEK5 and ERK5 expression in colon cancer progression and to ascertain the relevance of MEK5/ERK5 signalling in colon cancer. Expression of MEK5 and ERK5 was evaluated in 323 human colon cancer samples. To evaluate the role of MEK5/ERK5 signalling in colon cancer, we developed a stable cell line model with differential MEK5/ERK5 activation. Impact of differential MEK5/ERK5 signalling was evaluated on cell cycle progression by flow cytometry and cell migration was evaluated by wound healing and transwell migration assays. Finally, we used an orthotopic xenograft mouse model of colon cancer to assess tumour growth and progression. Our results demonstrated that MEK5 and ERK5 are overexpressed in human adenomas (P<0.01) and adenocarcinomas (P<0.05), where increased ERK5 expression correlated with the acquisition of more invasive and metastatic potential (P<0.05). Interestingly, we observed a significant correlation between ERK5 expression and NF-κB activation in human adenocarcinomas (P<0.001). We also showed that ERK5 overactivation significantly accelerated cell cycle progression (P<0.05) and increased cell migration (P<0.01). Furthermore, cells with overactivated ERK5 displayed increased NF-κB nuclear translocation and transcriptional activity (P<0.05), together with increased expression of the mesenchymal marker vimentin (P<0.05). We further demonstrated that increased NF-κB activation was associated with increased IκB phosphorylation and degradation (P<0.05). Finally, in the mouse model, lymph node metastasis was exclusively seen in orthotopically implanted tumours with overactivated MEK5/ERK5, and not in tumours with inhibited MEK5/ERK5. Our results suggested that MEK5/ERK5/NF-κB signalling pathway is important for tumour onset, progression and metastasis, possibly representing a novel relevant therapeutic target in colon cancer treatment.This study was supported by Fundação para a Ciência e Tecnologia (HMSP-ICT/0018/2011, SFRH/BD/96517/2013, SFRH/BD/88619/2012 and SFRH/BD/79356/2011).info:eu-repo/semantics/publishedVersio

    OCT1 polymorphism is associated with response and survival time in anti-Parkinsonian drug users

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    Substrates for the Organic Cation Transporter 1, encoded by the SLC22A1 gene, are metformin, amantadine, pramipexole, and, possibly, levodopa. Recently, we identified that the rs622342 A > C polymorphism is associated with the HbA1c lowering effect in metformin users. In the Rotterdam Study, we associated this polymorphism with higher prescribed doses of all anti-Parkinsonian drugs. Between the first and fifth prescriptions for levodopa, for each minor rs622342 C allele, the prescribed doses were 0.34 defined daily dose higher (95% CI 0.064, 0.62; p = 0.017). The mortality ratio after start of levodopa therapy was 1.47 times higher (95% CI 1.01, 2.13; p = 0.045)

    Female Specific Association of Low Insulin-Like Growth Factor 1 (IGF1) Levels with Increased Risk of Premature Mortality in Renal Transplant Recipients

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    Associations between insulin-like growth factor 1 (IGF1) and mortality have been reported to be female specific in mice and in human nonagenarians. Intervention in the growth hormone (GH)-IGF1 axis may particularly benefit patients with high risk of losing muscle mass, including renal transplant recipients (RTR). We investigated whether a potential association of circulating IGF1 with all-cause mortality in stable RTR could be female specific and mediated by variation in muscle mass. To this end, plasma IGF1 levels were measured in 277 female and 343 male RTR by mass spectrometry, and their association with mortality was assessed by Cox regression. During a median follow-up time of 5.4 years, 56 female and 77 male RTR died. In females, IGF1 was inversely associated with risk (hazard ratio (HR) per 1-unit increment in log2-transformed (doubling of) IGF1 levels, 95% confidence interval (CI)) of mortality (0.40, 0.24-0.65; p < 0.001), independent of age and the estimated Glomerular filtration rate (eGFR). In equivalent analyses, no significant association was observed for males (0.85, 0.56-1.29; p = 0.44), for which it should be noted that in males, age was negatively and strongly associated with IGF1 levels. The association for females remained materially unchanged upon adjustment for potential confounders and was furthermore found to be mediated for 39% by 24 h urinary creatinine excretion. In conclusion, low IGF1 levels associate with an increased risk of all-cause mortality in female RTR, which may link to conditions of low muscle mass that are known to be associated with poor outcomes in transplantation patients. For males, the strongly negative association of age with IGF1 levels may explain why low IGF1 levels were not found to be associated with an increased risk of all-cause mortality
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