155 research outputs found
An ex-post analysis of selected road investments in the Świętokrzyskie region in 2007–2016
Motivation: A great number of road investments are currently underway in Poland. Analysing their efficiency requires a range of forecasts and estimates which are not always corroborated by reality. This is due to both objective and subjective causes. Improvements to methods of analysing the efficiency of transport infrastructure investments can be based on ex-post analysis results. These results should serve to eliminate errors and consequently improve the quality of ex-ante analyses.Aim: The paper aims to identify, based on ex-post analysis, divergences between assumed and real properties of road investments that have key effects on the results of ex-ante efficiency calculus of the investments.Results: The study was based on selected investments in national and regional roads in the Świętokrzyskie region in 2007–2016. The ex-post analysis has shown that the capital expenditure and traffic volumes were overestimated, with ADT overestimation reaching nearly as much as 50% in four cases. Most investments were completed on time. There was a substantial delay in only one case. The overestimations of capital expenditure and traffic volume have a significant impact on the ex-ante evaluation of road investment efficiency, which may lead to misguided decisions when choosing the projects to be completed. The analysis results are a starting point for continuing the research and an indication of the need to improve the quality of ex-ante analyses
Damage in graphene due to electronic excitation induced by highly charged ions
Graphene is expected to be rather insensitive to ionizing particle radiation.
We demonstrate that single layers of exfoliated graphene sustain significant
damage from irradiation with slow highly charged ions. We have investigated the
ion induced changes of graphene after irradiation with highly charged ions of
different charge states (q = 28-42) and kinetic energies E_kin = 150-450 keV.
Atomic force microscopy images reveal that the ion induced defects are not
topographic in nature but are related to a significant change in friction. To
create these defects, a minimum charge state is needed. In addition to this
threshold behaviour, the required minimum charge state as well as the defect
diameter show a strong dependency on the kinetic energy of the projectiles.
From the linear dependency of the defect diameter on the projectile velocity we
infer that electronic excitations triggered by the incoming ion in the
above-surface phase play a dominant role for this unexpected defect creation in
graphene
Modelling and Optimization of the Air Operational Manoeuvre
Increasing complexity of the operational environment and advanced technology implementation in combat will probably lead to a serious limitation of human performance in all operational domains and activities in the future. With except of the clear indications, that tactical robotics will outperform human soldiers in many routine tasks on the battlefield, the area of operational decision making (resistible for decades to some automation) seems to be slowly approaching to the same stage. Presented article discusses the fundamental theory of optimization of the air operational maneuver and present the approach to the solution. The solution is highly theoretical and uses a modelling and simulation as an experimental platform to the visualization and evaluation of solution. The problem of air operational maneuver is specific in this case by many variables imposed on initial parametrization of the task (starting and destination point could not be known at the beginning, only \u201cair operational\u201d area should be selected) and very wide search of possible courses of action and the best \u201cmulti criteria\u201d choice identification
Differential expression of exosomal microRNAs in prefrontal cortices of schizophrenia and bipolar disorder patients
Exosomes are cellular secretory vesicles containing microRNAs (miRNAs). Once secreted, exosomes are able to attach to recipient cells and release miRNAs potentially modulating the function of the recipient cell. We hypothesized that exosomal miRNA expression in brains of patients diagnosed with schizophrenia (SZ) and bipolar disorder (BD) might differ from controls, reflecting either disease-specific or common aberrations in SZ and BD patients. The sources of the analyzed samples included McLean 66 Cohort Collection (Harvard Brain Tissue Resource Center), BrainNet Europe II (BNE, a consortium of 18 brain banks across Europe) and Boston Medical Center (BMC). Exosomal miRNAs from frozen postmortem prefrontal cortices with well-preserved RNA were isolated and submitted to profiling by Luminex FLEXMAP 3D microfluidic device. Multiple statistical analyses of microarray data suggested that certain exosomal miRNAs were differentially expressed in SZ and BD subjects in comparison to controls. RT-PCR validation confirmed that two miRNAs, miR-497 in SZ samples and miR-29c in BD samples, have significantly increased expression when compared to control samples. These results warrant future studies to evaluate the potential of exosome-derived miRNAs to serve as biomarkers of SZ and BD
Creating nanoporous graphene with swift heavy ions
This article has an erratum: DOI 10.1016/j.carbon.2017.03.065We examine swift heavy ion-induced defect production in suspended single layer graphene using Raman spectroscopy and a two temperature molecular dynamics model that couples the ionic and electronic subsystems. We show that an increase in the electronic stopping power of the ion results in an increase in the size of the pore-type defects, with a defect formation threshold at 1.22–1.48 keV/layer. We also report calculations of the specific electronic heat capacity of graphene with different chemical potentials and discuss the electronic thermal conductivity of graphene at high electronic temperatures, suggesting a value in the range of 1 Wm−1 K−1. These results indicate that swift heavy ions can create nanopores in graphene, and that their size can be tuned between 1 and 4 nm diameter by choosing a suitable stopping power.Peer reviewe
Turnip mosaic potyvirus probably first spread to Eurasian brassica crops from wild orchids about 1000 years ago
Turnip mosaic potyvirus (TuMV) is probably the most widespread and damaging virus that infects cultivated brassicas worldwide. Previous work has indicated that the virus originated in western Eurasia, with all of its closest relatives being viruses of monocotyledonous plants. Here we report that we have identified a sister lineage of TuMV-like potyviruses (TuMV-OM) from European orchids. The isolates of TuMV-OM form a monophyletic sister lineage to the brassica-infecting TuMVs (TuMV-BIs), and are nested within a clade of monocotyledon-infecting viruses. Extensive host-range tests showed that all of the TuMV-OMs are biologically similar to, but distinct from, TuMV-BIs and do not readily infect brassicas. We conclude that it is more likely that TuMV evolved from a TuMV-OM-like ancestor than the reverse. We did Bayesian coalescent analyses using a combination of novel and published sequence data from four TuMV genes [helper component-proteinase protein (HC-Pro), protein 3(P3), nuclear inclusion b protein (NIb), and coat protein (CP)]. Three genes (HC-Pro, P3, and NIb), but not the CP gene, gave results indicating that the TuMV-BI viruses diverged from TuMV-OMs around 1000 years ago. Only 150 years later, the four lineages of the present global population of TuMV-BIs diverged from one another. These dates are congruent with historical records of the spread of agriculture in Western Europe. From about 1200 years ago, there was a warming of the climate, and agriculture and the human population of the region greatly increased. Farming replaced woodlands, fostering viruses and aphid vectors that could invade the crops, which included several brassica cultivars and weeds. Later, starting 500 years ago, inter-continental maritime trade probably spread the TuMV-BIs to the remainder of the world
Response of GaN to energetic ion irradiation: conditions for ion track formation
We investigated the response of wurzite GaN thin films to energetic ion irradiation. Both swift heavy ions (92 MeV Xe23+, 23 MeV I6+) and highly charged ions (100 keV Xe40+) were used. After irradiation, the samples were investigated using atomic force microscopy, grazing incidence small angle X-ray scattering, Rutherford backscattering spectroscopy in channelling orientation and time of flight elastic recoil detection analysis. Only grazing incidence swift heavy ion irradiation induced changes on the surface of the GaN, when the appearance of nanoholes is accompanied by a notable loss of nitrogen. The results are discussed in the framework of the thermal spike model
Loss of miR-204 expression is a key event in melanoma
Cutaneous melanoma (CM) is a malignancy with increasing occurrence. Its microRNA repertoire has been defined in a number studies, leading to candidates for biological and clinical relevance: miR-200a/b/c, miR-203, miR-205, miR-204, miR-211, miR-23b and miR-26a/b. Our work was aimed to validate the role of these candidate miRNAs in melanoma, using additional patients cohorts and in vitro cultures. miR-26a, miR-204 and miR-211 were more expressed in normal melanocytes, while miR-23b, miR-200b/c, miR-203 and miR-205 in epidermis and keratinocytes. None of the keratinocyte-related miRNAs was associated with any known mutation or with clinical covariates in melanoma.
On the other hand, the loss of miR-204 was enriched in melanomas with NRAS sole mutation (Fisher exact test, P = 0.001, Log Odds = 1.67), and less frequent than expected in those harbouring CDKN2A mutations (Fisher exact test, P = 0.001, Log Odds − 1.09). Additionally, miR-204 was associated with better prognosis in two independent melanoma cohorts and its exogenous expression led to growth impairment in melanoma cell lines. Thus, miR-204 represents a relevant mechanism in melanoma, with potential prognostic value and its loss seems to act in the CDKN2A pathway, in cooperation with NRAS
An objective comparison of cell-tracking algorithms
We present a combined report on the results of three editions of the Cell Tracking Challenge, an ongoing initiative aimed at promoting the development and objective evaluation of cell segmentation and tracking algorithms. With 21 participating algorithms and a data repository consisting of 13 data sets from various microscopy modalities, the challenge displays today's state-of-the-art methodology in the field. We analyzed the challenge results using performance measures for segmentation and tracking that rank all participating methods. We also analyzed the performance of all of the algorithms in terms of biological measures and practical usability. Although some methods scored high in all technical aspects, none obtained fully correct solutions. We found that methods that either take prior information into account using learning strategies or analyze cells in a global spatiotemporal video context performed better than other methods under the segmentation and tracking scenarios included in the challenge
Pairing of Homologous Regions in the Mouse Genome Is Associated with Transcription but Not Imprinting Status
This work was funded by the BBSRC, grant BB/H088071/1 (www.bbsrc.ac.uk), MRC, grant G0700760 (www.mrc.ac.uk), Wellcome Trust, grant 095645/Z/11/Z (www.wellcome.ac.uk) and the EU through EpiGeneSys (www.epigenesys.eu) and Blueprint (www.blueprint-epigenome.eu). C.K. was funded by the DFG, personal fellowship KR 3317/2-1 (www.dfg.de) and CTR, personal short term fellowship (www.trophoblast.cam.ac.uk). M.J.H. received funding through grant NCI/NIH 2RO1 CA089426 (www.nih.gov)
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