487 research outputs found

    Determining appropriate approaches for using data in feature selection

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    Feature selection is increasingly important in data analysis and machine learning in big data era. However, how to use the data in feature selection, i.e. using either ALL or PART of a dataset, has become a serious and tricky issue. Whilst the conventional practice of using all the data in feature selection may lead to selection bias, using part of the data may, on the other hand, lead to underestimating the relevant features under some conditions. This paper investigates these two strategies systematically in terms of reliability and effectiveness, and then determines their suitability for datasets with different characteristics. The reliability is measured by the Average Tanimoto Index and the Inter-method Average Tanimoto Index, and the effectiveness is measured by the mean generalisation accuracy of classification. The computational experiments are carried out on ten real-world benchmark datasets and fourteen synthetic datasets. The synthetic datasets are generated with a pre-set number of relevant features and varied numbers of irrelevant features and instances, and added with different levels of noise. The results indicate that the PART approach is more effective in reducing the bias when the size of a dataset is small but starts to lose its advantage as the dataset size increases

    Avatar Based Multiplayer Functionalities in Next Generation Communication and Learning in Virtual Reality Social Platforms – Case MarISOT Room

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    Virtual Reality Social Platforms are increasingly in use in conferences, and exhibitions. COVID19 pandemic is the main reason for a rapid growth but there are reasons such as climate change to believe these technologies will be used widely once we will enter to the post pandemic era. In this paper, we will introduce our vision to combine social functioning and hands-on-training features in one package. We have participated in and organized various events using existing virtual reality social platforms. We will analyze in this paper their pros and cons plus introduce our own technology trials. As a result, we have better understanding what development tools and how much resources would be needed to be able to create the first minimal viable product combining social functioning and hands-on-training features

    Characterization of Highly Mucus-Adherent Non-GMO Derivatives of Lacticaseibacillus rhamnosus GG

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    Lacticaseibacillus rhamnosusGG is one of the best studied lactic acid bacteria in the context of probiotic effects.L. rhamnosusGG has been shown to prevent diarrhea in children and adults and has been implicated to have mitigating or preventive effects in several disorders connected to microbiota dysbiosis. The probiotic effects are largely attributed to its adhesive heterotrimeric sortase-dependent pili, encoded by thespaCBA-srtC1gene cluster. Indeed, the strain-specific SpaCBA pili have been shown to contribute to adherence, biofilm formation and host signaling. In this work we set out to generate non-GMO derivatives ofL. rhamnosusGG that adhere stronger to mucus compared to the wild-type strain using chemical mutagenesis. We selected 13 derivatives that showed an increased mucus-adherent phenotype. Deep shotgun resequencing of the strains enabled division of the strains into three classes, two of which revealed SNPs (single nucleotide polymorphisms) in thespaAandspaCgenes encoding the shaft and tip adhesive pilins, respectively. Strikingly, the other class derivatives demonstrated less clear genotype - phenotype relationships, illustrating that pili biogenesis and structure is also affected by other processes. Further characterization of the different classes of derivatives was performed by PacBio SMRT sequencing and RNAseq analysis, which resulted in the identification of molecular candidates driving pilin biosynthesis and functionality. In conclusion, we report on the generation and characterization of three classes of strongly adherentL. rhamnosusGG derivatives that show an increase in adhesion to mucus. These are of special interest as they provide a window on processes and genes driving piliation and its control inL. rhamnosusGG and offer a variety of non-GMO derivatives of this key probiotic strain that are applicable in food products.Peer reviewe

    Examining the Seyfert - Starburst Connection with Arcsecond Resolution Radio Continuum Observations

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    We compare the arcsecond-scale circumnuclear radio continuum properties between five Seyfert and five starburst galaxies, concentrating on the search for any structures that could imply a spatial or causal connection between the nuclear activity and a circumnuclear starburst ring. No evidence is found in the radio emission for a link between the triggering or feeding of nuclear activity and the properties of circumnuclear star formation. Conversely, there is no clear evidence of nuclear outflows or jets triggering activity in the circumnuclear rings of star formation. Interestingly, the difference in the angle between the apparent orientation of the most elongated radio emission and the orientation of the major axis of the galaxy is on average larger in Seyferts than in starburst galaxies, and Seyferts appear to have a larger physical size scale of the circumnuclear radio continuum emission. The concentration, asymmetry, and clumpiness parameters of radio continuum emission in Seyferts and starbursts are comparable, as are the radial profiles of radio continuum and near-infrared line emission. The circumnuclear star formation and supernova rates do not depend on the level of nuclear activity. The radio emission usually traces the near-infrared Br-gamma and H2 1-0 S(1) line emission on large spatial scales, but locally their distributions are different, most likely because of the effects of varying local magnetic fields and dust absorption and scattering.Comment: 21 pages, 10 figures. Accepted for publication in the Astronomical Journa

    Aktiivisuutta ja osallistumista tukeva fysioterapia aivoverenkiertohäiriöön sairastuneiden alkuvaiheen kuntoutuksessa : Satunnaistettu seurantatutkimus

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    Satunnaistettu seurantatutkimus Aktiivisuutta ja osallistumista tukeva fysioterapia aivoverenkiertohäiriöön (AVH) sairastuneiden alkuvaiheen kuntoutuksessa toteutettiin vuosina 2008–2013. Tutkimuksessa selvitettiin laaja-alaisia toimintakyvyn muutoksia ja kuntoutujien ja heidän omaistensa kokemuksia sekä terveys- ja sosiaalipalvelujen käyttöä aktivoivassa ja perinteisessä fysioterapiassa. 108 osallistumiskriteerit täyttänyttä kuntoutujaa satunnaistettiin aktivoivan ja perinteisen fysioterapian ryhmiin. Aktivoivan fysioterapian ryhmän kuntoutus tuki kuntoutujien aktiivista osallistumista ja kotiutumista. Seurannan aikana molempien ryhmien toimintakyky parani eikä ryhmien välillä ollut tilastollisesti merkitseviä eroja. Aktivoiva ryhmä käytti perinteiseen ryhmään verrattuna puolet vähemmän perusterveydenhuollon laitoshoitopäiviä, mutta ero ei ollut tilastollisesti merkitsevä. Perusterveydenhuollon kuntoutujakohtaiset kustannukset vuodessa olivat aktivoivassa ryhmässä 1 200 € perinteistä ryhmää pienemmät. Alkuvaiheen kuntoutuksen intensiivisyys, suunnitelmallinen seuranta ja moniammatillinen työote molemmissa ryhmissä on saattanut vaikuttaa tuloksiin. Aktiivisuutta tukeva fysioterapiaote oli vakiintunut fysioterapeuttien toimintatavaksi, mikä vähensi intervention vertailtavuutta ryhmien välillä. Kuntoutujien kokemukset haastavat fysioterapeutit syventämään moniammatillista yhteistyötä ja siirtämään painopistettä kuntoutujan elinympäristöön ja sosiaaliseen osallistumiseen. Tulevaisuudessa AVH-kuntoutusta tulisi tutkia myös tarkastelemalla, voidaanko kuntoutuksella ehkäistä sairauden uusiutumista ja siten vaikuttaa AVH:sta johtuviin terveydenhuollon kokonaiskustannuksiin.25,00 euro

    Beacon Virtua: A Virtual Reality Simulation Detailing the Recent and Shipwreck History of Beacon Island, Western Australia

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    Beacon Virtua is a project to document and virtually preserve a historically significant offshore island as a virtual reality experience. In 1629, survivors of the wreck of VOC ship Batavia took refuge on Beacon Island, Western Australia, followed by a mutiny and massacre. In the 1950s the island became the base of a successful fishing industry, and in 1963 human remains from Batavia were located. The fishing community has recently been moved off the island to protect and preserve the site and allow a thorough archaeological investigation of the island. Beacon Virtua exposes users to the history of both the shipwreck survivors and the fishing community. The project uses the virtual environment development software Unity to present a simulation of the island, with 3D models of buildings and jetties, photogrammetric 3D reconstructions of graves and other features, 360° photographic panoramas, and information on the history of the island. The experience has been made available on a wide range of different platforms including via a web-page, as part of an exhibition, and on head mounted displays (VR headsets). This chapter discusses the features included in Beacon Virtua, the storytelling techniques used in the simulation, the challenges encountered and solutions used during the project

    Shutting down or powering up a (U)LIRG? Merger components in distinctly different evolutionary states in IRAS 19115-2124 (the Bird)

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    We present new SINFONI near-infrared (NIR) integral field unit (IFU) spectroscopy and Southern African Large Telescope (SALT) optical long-slit spectroscopy characterizing the history of a nearby merging luminous infrared galaxy, dubbed the Bird (IRAS19115-2124). TheNIR line-ratio maps of the IFU data cubes and stellar population fitting of the SALT spectra now allow dating of the star formation (SF) over the triple system uncovered from our previous adaptive optics data. The distinct components separate clearly in line-ratio diagnostic diagrams, both thermal and non-thermal excitation is present. An off-nuclear starburst dominates the current SF of the Bird with 60-70 per cent of the total, with a 4-7 Myr age. The most massive nucleus, in contrast, is quenched with a starburst age of >40 Myr and shows hints of budding active galactic nucleus (AGN) activity. The secondary massive nucleus is at an intermediate stage. The two major components have signs of an older stellar population, consistent with a starburst triggered 1 Gyr ago in a first encounter. The simplest explanation of the history is that of a triple merger, where the strongly star-forming component has joined later. We detect multiple gas flows. The Bird offers an opportunity to witness multiple stages of galaxy evolution in the same system; triggering as well as very recent quenching of SF, and, perhaps, an early appearance of AGN activity. It also serves as a cautionary note on interpretations of observations with lower spatial resolution and/or without infrared data. At high redshift the system would look like a clumpy starburst with crucial pieces of its puzzle hidden in danger of misinterpretations

    Feeding versus Feedback in NGC 4151 probed with Gemini NIFS. I. Excitation

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    We have used the Gemini Near-infrared Integral Field Spectrograph (NIFS) to map the emission-line intensity distributions and ratios in the Narrow-Line Region (NLR) of the Seyfert galaxy NGC 4151 in the Z, J, H and K bands at a resolving power ~ 5000, covering the inner 200 pc x 300 pc of the galaxy at a spatial resolution of 8 pc. We present intensity distributions I(r) in 14 emission lines. (1) For the ionized gas, I(r) is extended to ~ 100 pc from the nucleus along pos. angle PA=60/240 deg-- NE--SW), consistent with an origin in the known biconical outflow; while for the recombination lines I(r) ~ r^-1, for the forbidden lines I(r) is flat (r^0). (2) The H_2 emission lines intensity distributions avoid the region of the bicone, extending to r ~ 60 pc, perpendicular to the bicone axis, supporting an origin for the H_2-emitting gas in the galaxy plane. (3) The coronal lines show a steep intensity profile, described by r^-2. Using the line-ratio maps [Fe II]1.644/1.257 and Pa_b/Br_g we obtain a reddening of E(B-V)~0.5 along the NLR and E(B-V)>1 at the nucleus. Our line-ratio map [Fe II] 1.257/[P II] 1.189 is the first such map of an extragalactic source. Together with the [Fe II]/Pa_b map, these line ratios correlate with the radio intensity distribution, mapping the effects of shocks produced by the radio jet, which probably release the Fe locked in grains and produce the enhancement of the [Fe II] emission observed at ~ 1 arcsec from the nucleus. At these regions, we obtain densities N_e ~4000 cm^-3 and temperatures T_e ~ 15000K for the [Fe II]-emitting gas. For the H_2-emitting gas we obtain T ~ 2100K. The distinct intensity distributions, physical properties and locations of the ionized and molecular gas suggest that the H_2-emitting gas traces the AGN feeding, while the ionized gas traces its feedback.Comment: 22 pages. 14 figures, accepted for publication in MNRA

    Nuclear and Extended Spectra of NGC 1068 - I: Hints from Near-Infrared Spectroscopy

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    We report the first simultaneous zJHK spectroscopy on the archetypical Seyfert 2 Galaxy NGC 1068 covering the wavelength region 0.9 to 2.4 micron. The slit, aligned in the NS direction and centred in the optical nucleus, maps a region 300 pc in radius at sub-arcsec resolution, with a spectral resolving power of 360 km s^-1. This configuration allow us to study the physical properties of the nuclear gas including that of the north side of the ionization cone, map the strong excess of continuum emission in the K-band and attributed to dust and study the variations, both in flux and profile, in the emission lines. Our results show that (1) Mid- to low-ionization emission lines are splitted into two components, whose relative strengths vary with the position along the slit and seem to be correlated with the jet. (2) The coronal lines are single-peaked and are detected only in the central few hundred of parsecs from the nucleus. (3) The absorption lines indicate the presence of intermediate age stellar population, which might be a significant contributor to the continuum in the NIR spectra. (4) Through some simple photoionization models we find photoionization as the main mechanism powering the emitting gas. (5) Calculations using stellar features point to a mass concentration inside the 100 - 200 pc of about 10^10 solar masses.Comment: 19 Pages, 14 figures. Accepted for publication in MNRA
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