911 research outputs found
Basic parameters of three star clusters in the Small Magellanic Cloud: Kron 11, Kron 63 and NGC 121
We present observations for three star clusters, Kron 11, Kron 63 and NGC 121, in the Small Magellanic Cloud. We have studied their structure and derived their fundamental parameters by means of their luminosity functions, their colour magnitude diagrams and the Padova suite of isochrones. NGC 121 is a well-studied object, for which we confirm previous evidence about its old age and low-metal content, and have found that it is an undergoing mass segregation. Kron 11 and Kron 63 are poorly populated clusters which had never been studied so far. Kron 11 is several gigayears younger than NGC 121, while Kron 63 is basically a very young star aggregate. Both clusters are immersed in dense stellar fields which share the same population properties, suggesting that in their cases, cluster ages are consistent with typical ages of field stars.Instituto de Astrofísica de La PlataFacultad de Ciencias Astronómicas y Geofísica
Basic parameters of three star clusters in the Small Magellanic Cloud: Kron 11, Kron 63 and NGC 121
We present observations for three star clusters, Kron 11, Kron 63 and NGC 121, in the Small Magellanic Cloud. We have studied their structure and derived their fundamental parameters by means of their luminosity functions, their colour magnitude diagrams and the Padova suite of isochrones. NGC 121 is a well-studied object, for which we confirm previous evidence about its old age and low-metal content, and have found that it is an undergoing mass segregation. Kron 11 and Kron 63 are poorly populated clusters which had never been studied so far. Kron 11 is several gigayears younger than NGC 121, while Kron 63 is basically a very young star aggregate. Both clusters are immersed in dense stellar fields which share the same population properties, suggesting that in their cases, cluster ages are consistent with typical ages of field stars.Instituto de Astrofísica de La PlataFacultad de Ciencias Astronómicas y Geofísica
Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural
8 págs.; 2 figs.; 2 tabs.We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20-250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron-furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.D.B.J. thanks the Australian Research Council (ARC) for
financial support provided through a Discovery Early Career
Research Award, while M.J.B. also thanks the ARC for their
support. M.J.B. acknowledges the Brazilian agency CNPq
for his “Special Visiting Professor” position at the Federal
University of Juiz de Fora. G.G. acknowledges partial financial
support from the Spanish Ministry MINECO (Project No.
FIS2012-31230) and the European Union COST Action No.
CM1301 (CELINA). Finally R.F.C., M.T.doN.V, M.H.F.B,
and M.A.P.L. also acknowledge support from CNPq, while
M.T.doN.V. thanks FAPESPPeer Reviewe
财务治理机制—审计委员会制度研究
本论文属于应用性与实务性的审计研究。 注册会计师对公司财务报告的审计厥为审计理论与实务研究的重心,但注册会计师的审计功能能否充分发挥,核与审计环境有直接且密切的关系。独立、客观与公正固为注册会计师执行业务的基本守则,但确保注册会计师恪守独立、客观、公正的审计环境如果不存在,则社会大众对注册会计师公信力的信任与要求,必然与实际产生差距。1987年,美国不实财务报告全国委员会针对愈来愈多的上市公司财务报告不实与舞弊着手调查,其调查报告即认为财务报告不实与企业内部控制不良、管理当局意图及注册会计师的独立性息息相关;而前二者正与审计环境有关,并且制约了注册会计师的独立性。笔者认为,改善审计环境乃提升...This dissertation studies the applicable auditing theory and practices. The center of auditing theory and practical studies lies in the CPA’s financial report audit. However, the audit environment plays a close and direct role in whether the CPA may fully perform the audit process. Independence, objectiveness and justice are the basic rules of CPAs professional. If such criteria cannot be ensu...学位:管理学博士院系专业:管理学院会计系_会计学学号:B19971101
Combined expression of p20 and p23 proteins from Citrus tristeza virus show enhanced local silencing suppressor activity
Viruses developed a strategy to counter-defence the posttranscriptional gene silencing mechanism (PTGS) based on the activity of silencing suppressor proteins. Citrus tristeza virus (CTV), a member of the genus Closterovirus, has two suppressor proteins (p20 and p23) that target the local RNA silencing response of the host. In GFP transient co-expression assays performed on Nicotiana benthamiana 16C plants, local suppressor activity of p23 and p20 was similar. Co-expression of both proteins from a mild or a stem pitting CTV isolate showed stronger local suppression activity than either suppressor alone, with an increased GFP transcript level six-(for Gp M) to nine-fold (for Gp 3a) higher than non-inoculated 16C plants, in parallel with low accumulation of siRNAs. Further, GFP brightness of leaves infiltrated with Agrobacterium cultures at an OD600 of 0.5 was comparable to those infiltrated with OD600 0.25. These findings indicate that combined action of p20 and p23 proteins results in enhanced suppressor activity
Frondose and turf-dominated marine habitats support distinct trophic pathways: evidence from ¹⁵N and ¹³C stable isotope analyses
Marine vegetation plays an important structuring role, delivering key functions and services to coastal systems the extent of which depends on the foundation species and their architecture. In increasingly urbanised coastlines, turf-forming macroalgae are replacing frondose morphotypes. Trophic relationships within these systems can be studied through stable isotope analysis of the different food web compartments. In the present study, we investigated trophic pathways in two distinct macroalgal assemblages: one dominated by small brown frondose algae, and one dominated by low-lying turf-forming species. ¹⁵N and ¹³C isotopic signatures were determined for selected macroalgae and sedentary animals from distinct trophic levels, collected from two habitats on São Miguel Island (Azores, Portugal). In frondose habitats macroalgae appeared to make up the primary carbon source for the entire food web, whilst in turf-dominated habitats there was a decouple between macroalgae and higher trophic levels.
Because canopy replacement by algal turf may affect the structure of the littoral food webs, coastal biodiversity conservation strategies should give priority to natural areas rich in canopy-forming algae.This research was supported by the European Commission BEST Preparatory Action, under the project “ECOSUBVEG – Changes in submersed vegetation: assessing loss in ecosystems services from frondose to depauperate systems dominated by opportunistic vegetation”, ref. 07.032700/2012/635752/SUB/B2. The research was also partially supported by Portuguese National Funds, through FCT – Fundação para a Ciência e a Tecnologia, within the projects UID/BIA/00329/2013, 2015 - 2018, UID/BIA/00329/2019 and UID/BIA/00329/2020-2023. Logistic support was also provided by CIRN/UAc (Centre of natural Resources of University of the Azores) and by CVARG (Centro de Vulcanologia e Avaliação de Riscos Geológicos). GMM was supported by a post-doctoral grant awarded by FCT (SFRH/BDP/63040/2009 and SFRH/BDP/108114/2015).info:eu-repo/semantics/publishedVersio
tackling malaria
Malaria is an infectious disease that affects over 216 million people worldwide, killing over 445,000 patients annually. Due to the constant emergence of parasitic resistance to the current antimalarial drugs, the discovery of new drug candidates is a major global health priority. Aiming to make the drug discovery processes faster and less expensive, we developed binary and continuous Quantitative Structure-Activity Relationships (QSAR) models implementing deep learning for predicting antiplasmodial activity and cytotoxicity of untested compounds. Then, we applied the best models for a virtual screening of a large database of chemical compounds. The top computational predictions were evaluated experimentally against asexual blood stages of both sensitive and multi-drug-resistant Plasmodium falciparum strains. Among them, two compounds, LabMol-149 and LabMol-152, showed potent antiplasmodial activity at low nanomolar concentrations (EC50 <500 nM) and low cytotoxicity in mammalian cells. Therefore, the computational approach employing deep learning developed here allowed us to discover two new families of potential next generation antimalarial agents, which are in compliance with the guidelines and criteria for antimalarial target candidates.publishersversionpublishe
The electron-furfural scattering dynamics for 63 energetically open electronic states
14 págs.; 15 figs.We report on integral-, momentum transfer- and differential cross sections for elastic and electronically inelastic electron collisions with furfural (CHO). The calculations were performed with two different theoretical methodologies, the Schwinger multichannel method with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR) that now incorporates a further interference (I) term. The SMCPP with N energetically open electronic states (N) at either the static-exchange (N ch-SE) or the static-exchange-plus-polarisation (N ch-SEP) approximation was employed to calculate the scattering amplitudes at impact energies lying between 5 eV and 50 eV, using a channel coupling scheme that ranges from the 1ch-SEP up to the 63ch-SE level of approximation depending on the energy considered. For elastic scattering, we found very good overall agreement at higher energies among our SMCPP cross sections, our IAM-SCAR+I cross sections and the experimental data for furan (a molecule that differs from furfural only by the substitution of a hydrogen atom in furan with an aldehyde functional group). This is a good indication that our elastic cross sections are converged with respect to the multichannel coupling effect for most of the investigated intermediate energies. However, although the present application represents the most sophisticated calculation performed with the SMCPP method thus far, the inelastic cross sections, even for the low lying energy states, are still not completely converged for intermediate and higher energies. We discuss possible reasons leading to this discrepancy and point out what further steps need to be undertaken in order to improve the agreement between the calculated and measured cross sections. ©2016 AIP Publishing LLCR.F.d.C., M.C.A.L., M.H.F.B., M.T.d.N.V.,
and M.A.P.L. acknowledge support from the Brazilian
agency Conselho Nacional de Desenvolvimento Científico
e Tecnológico (CNPq). M.T.d.N.V. acknowledges support
from Fundação de Amparo à Pesquisa do Estado de São Paulo
(FAPESP). D.B.J. thanks the Australian Research Council
(ARC) for financial support provided through a Discovery
Early Career Researcher Award. M.J.B. thanks the ARC
for some financial support and also thanks CNPq for his
“Special Visiting Professor” award at the Federal University
of Juiz de Fora. G.G. thanks the Spanish Ministerio de
Economia y Competitividad under Project No. FIS2012-
31230 and the European Union COST Action No. CM1301
for funding.Peer Reviewe
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