430 research outputs found

    Per-pixel Cloud Cover Classification of Multispectral Landsat-8 Data

    Get PDF
    Random forest and neural network algorithms are applied to identify cloud cover using 10 of the wavelength bands available in Landsat 8 imagery. The methods classify each pixel into 4 different classes: clear, cloud shadow, light cloud, or cloud. The first method is based on a fully connected neural network with ten input neurons, two hidden layers of 8 and 10 neurons respectively, and a single-neuron output for each class. This type of model is considered with and without L2 regularization applied to the kernel weighting. The final model type is a random forest classifier created from an ensemble of decision trees acting on a randomized subset of 6 wavelengths. The best performing classifier is the random forest, with an overall accuracy of 77% across the 4 classes. Cloud mask statistics could be incorporated in searchable metadata so that an imagery analyst can apply their subject matter expertise to advanced analytical techniques, rather than searching for cloud-free image sets

    Identity-Based Blind Signature Scheme with Message Recovery

    Get PDF
    Blind signature allows a user to obtain a signature on a message without revealing anything about the message to the signer. Blind signatures play an important role in many real world applications such as e-voting, e-cash system where anonymity is of great concern. Due to the rapid growth in popularity of both wireless communications and mobile devices, the design of secure schemes with low-bandwidth capability is an important research issue. In this paper, we present a new blind signature scheme with message recovery in the ID-based setting using bilinear pairings over elliptic curves. The proposed scheme is unforgeable with the assumption that the Computational Diffie-Hellman problem is hard. We compare our scheme with the related schemes in terms of computational and communicational point of view

    Energy Consumption in Wireless Sensor Network

    Get PDF
    Energy is a limited resource in wireless sensor networks. In fact, the reduction of power consumption is crucial to increase the lifetime of low power sensor networks. Wireless sensor networks consist of small, autonomous devices with wireless networking capabilities. In order to further increase the applicability in real world applications, minimizing power consumption is one of the most critical issues. Therefore, accurate power model is required for the evaluation of wireless sensor networks. To estimate the lifetime of sensor node, the energy characteristics of sensor node are measured. Research in this area has been growing in the past few years given the wide range of applications that can benefit from such a technology. Based on the proposed model, the estimated lifetime of a battery powered sensor node can be increased significantly. Keywords—Sensor, Wireless Sensor Network, Energy Consumptio

    Distinct and shared gene expression for human innate versus adaptive helper lymphoid cells

    Get PDF
    Innate lymphoid cells (ILCs) are the latest identified innate immune cell family. Given their similarity in transcription factor expression and cytokine secretion profiles, ILCs have been considered as the innate phenocopy of CD4 Th cells. Here, we explored the transcriptome of circulating human ILC subsets as opposed to CD4 Th cell subsets. We describe transcriptomic differences between total ILCs and total CD4 Th cells, as well as between paired innate and adaptive cell subsets (ILC1 vs. Th1; ILC2 vs. Th2; and ILC3 vs. Th17 cells). In particular, we observed differences in expression of genes involved in cell trafficking such as CCR1, CCR6 and CXCR3, innate activation and inhibitory functions, including CD119, 2B4, TIGIT, and CTLA-4, and neuropeptide receptors, such as VIPR2. Moreover, we report for the first time on distinct expression of long noncoding RNAs (lncRNAs) in innate vs. adaptive cells, arguing for a potential role of lncRNA in shaping human ILC biology. Altogether, our results point for unique, rather than redundant gene organization in ILCs compared to CD4 Th cells, in regard to kinetics, fine-tuning and spatial organization of the immune response

    Biological activity of folkloric plants used in the treatment of ‘u wela’ against pathogens

    Get PDF
    Background: ‘U wela’ also known as ‘Divhu’ in ‘Tshivenda’ is a sexually transmitted infection caused by a combination of fungal and bacterial microorganisms that affects males because of unprotected sexual encounters with a woman who has had an abortion or miscarriage. Aim: The study aimed to investigate medicinal plants used to treat ‘u wela’ and determine their biological activity against Neisseria gonorrhoeae and Candida albicans. Setting: Eight plant species (Elaeodendron transvaalense[Burtt Davy] R.H. Archer, Albizia versicolor Welw. ex Oliv, Xanthocercis zambesiaca Baker, Cassia abbreviata subsp. beareana [Holmes] Brenan, Anthocleista grandiflora Gilg, Myrothamnus flabellifolius Welw., Mimusops zeyheri Sond, and Capparis tomentosa Lam.) used to combat ‘u wela’ were selected from the Ethnomedicinal plant’s database of over 300 medicinal plants used for medicinal purposes in humans, in the Vhembe district, Limpopo province, South Africa. Methods: The antimicrobial activity of the plant extracts was investigated against Candida albicans and Neisseria gonorrhoeae using serial dilution and bioautography assays. Results: The plant extracts of A. versicolor and C. abbreviata had excellent activity with a low minimum inhibitory concentration (MIC). value of 0.02 and 0.07 mg/mL, respectively. In bioautograms developed in benzene/ethanol/ammonia hydroxide (BEA), active compounds were visible in the extracts of A. versicolor. Conclusion: A. versicolor had excellent antimicrobial activity and may be used in traditional therapy to combat ‘u wela’. Contribution: The study has demonstrated that A. versicolor is a promising plant species that could lead to the discovery of novel drugs to combat ‘u wela’

    Visualising myocardial injury after noncardiac surgery: a case series using postoperative cardiovascular MRI.

    Get PDF
    Myocardial injury after noncardiac surgery (MINS) and perioperative myocardial injury are associated with increased morbidity and mortality. Both are diagnosed by a perioperative increase in troponin, yet there is controversy if MINS is a genuine myocardial insult. We applied postoperative cardiovascular magnetic resonance T2 mapping techniques to visualise acute myocardial injury (i.e. oedema) in six patients with multiple cardiovascular risk factors who underwent aortic surgery. The burden of myocardial oedema was substantially higher in four patients with elevated troponin qualifying for MINS, compared with patients without MINS. The data and images suggest that MINS represents genuine myocardial injury

    Does absorption against AGN reveal supermassive black hole accretion?

    Get PDF
    Galaxies often contain large reservoirs of molecular gas that shape their evolution. This can be through cooling of the gas - which leads to star formation, or accretion on to the central supermassive black hole - which fuels active galactic nucleus (AGN) activity and produces powerful feedback. Molecular gas has been detected in early-type galaxies on scales of just a few tens to hundreds of solar masses by searching for absorption against their compact radio cores. Using this technique, ALMA has found absorption in several brightest cluster galaxies, some of which show molecular gas moving towards their galaxy's core at hundreds of km s-1. In this paper, we constrain the location of this absorbing gas by comparing each galaxy's molecular emission and absorption. In four galaxies, the absorption properties are consistent with chance alignments between the continuum and a fraction of the molecular clouds visible in emission. In four others, the properties of the absorption are inconsistent with this scenario. In these systems, the absorption is likely produced by a separate population of molecular clouds in close proximity to the galaxy core and with high inward velocities and velocity dispersions. We thus deduce the existence of two types of absorber, caused by chance alignments between the radio core and: (i) a fraction of the molecular clouds visible in emission, and (ii) molecular clouds close to the AGN, in the process of accretion. We also present the first ALMA observations of molecular emission in S555, Abell 2390, RXC J1350.3+0940, and RXC J1603.6+1553 - with the latter three having Mmol > 1010 MΞ

    Analyzing the Environmental Impacts and Potential Health Challenges Resulting From Artisanal Gold Mining in Shango Area of Minna, North-Central, Nigeria

    Full text link
    The environmental impact and potential health challenges resulting from artisanal mining in Shango area of Minna, North Central Nigeria was put into perspective. The methodology adopted for the research includes field work and laboratory analysis. Results of field observation reveal that mining activity resulted in physical environmental impact such as land degradation, destruction of vegetation, erosion of soils and degrading water quality. Results from the laboratory analyses show that soils are contaminated with elements such as Cu (27.7ppm), Cd (0.6 ppm), Hg (0.62 ppm) and Ag (0.35 ppm) and generally show high status when compared to published standard for upper continental crust. While, Zn (14.8ppm), Ni (7.17ppm), Mn (207ppm), Pb (0.58ppm), As (0.4ppm), Co (0.55ppm), Mo (0.16ppm), and Zr (129.8ppm) are rated low in line with the published standard; other determined elements such as Cr (37.8ppm), Fe (31.1ppm) and Au (0.2ppm) are high. These elements can easily be absorbed by plants and subsequently accumulate in their tissues. When such plants are eventually eaten by man, it may lead to different health problems such as slow growth rate, liver and kidney problem. High concentration of these elements in plant tissues may causes different problems

    Straighten your back! Self-correction posture and postural balance in 'non rehabilitative instructed' multiple sclerosis patients

    Get PDF
    BACKGROUD: Patients with MS, regardless of the complexity of the activity or sensory conditions, commonly present a significant postural control deficit compared to healthy subjects. OBJECTIVE: To investigate which postural self-correction strategies are adopted by patients with Multiple Sclerosis versus a group of healthy-subjects and how self-correction can influence the control of postural balance. METHODS: A case-control prospective observational study was conducted. Person with Multiple Sclerosis and a group of healthy volunteers were enrolled. Patients included were instructed with vocal commands, to reach a self-correction posture, and they were compared to healthy subjects. Clinical assessments including Balance, Stabilometry and Postural evaluation of the spine were performed. RESULTS: Sixty patients (30: control-group; 30: treatment-group) were enrolled. In the treatment group, the analysis reported a significant statistical difference between path length and center of pressure speed in self-correction posture with closed-eyes (p=0,049; 0,047) and an improvement in C7 and L3 levels in self-correction posture (p<0,01-C7; p<0,01-L3). There are significant statistical differences about path length between the two groups in all examined conditions (p=0,0001). At sagittal plane evaluation, results show an increase of all measurements in both posture (C7-neutral posture p=0,0001; L3-neutral posture p=0,0001; C7-self-correction posture p=0,0001; L3-self-correction posture p=0,0001). CONCLUSION: Further study should investigate dynamic situations and different Multiple Sclerosis forms to complete balance analysis and to establish a correct rehabilitative program with self-correction exercise as powerful focus

    Combined CO & Dust Scaling Relations of Depletion Time and Molecular Gas Fractions with Cosmic Time, Specific Star Formation Rate and Stellar Mass

    Get PDF
    We combine molecular gas masses inferred from CO emission in 500 star forming galaxies (SFGs) between z=0 and 3, from the IRAM-COLDGASS, PHIBSS1/2 and other surveys, with gas masses derived from Herschel far-IR dust measurements in 512 galaxy stacks over the same stellar mass/redshift range. We constrain the scaling relations of molecular gas depletion time scale (tdepl) and gas to stellar mass ratio (Mmolgas/M*) of SFGs near the star formation main-sequence with redshift, specific star formation rate (sSFR) and stellar mass (M*). The CO- and dust-based scaling relations agree remarkably well. This suggests that the CO-H2 mass conversion factor varies little within 0.6dex of the main sequence (sSFR(ms,z,M*)), and less than 0.3dex throughout this redshift range. This study builds on and strengthens the results of earlier work. We find that tdepl scales as (1+z)^-0.3 *(sSFR/sSFR(ms,z,M*))^-0.5, with little dependence on M*. The resulting steep redshift dependence of Mmolgas/M* ~(1+z)^3 mirrors that of the sSFR and probably reflects the gas supply rate. The decreasing gas fractions at high M* are driven by the flattening of the SFR-M* relation. Throughout the redshift range probed a larger sSFR at constant M* is due to a combination of an increasing gas fraction and a decreasing depletion time scale. As a result galaxy integrated samples of the Mmolgas-SFR rate relation exhibit a super-linear slope, which increases with the range of sSFR. With these new relations it is now possible to determine Mmolgas with an accuracy of 0.1dex in relative terms, and 0.2dex including systematic uncertainties.Comment: ApJ accepte
    • 

    corecore