954 research outputs found

    Poplar for biodiversity?

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    Due to increasing interest in the use of non-native tree species, more knowledge is needed concerning their effects on biodiversity. In this context, epiphytic lichens were investigated in two stands of non-native tree species (LarixĂ—eurolepis and Populus trichocarpa) and two stands of native tree species (Picea abies and Betula pendula) in a field experiment in southern Sweden. The trunks in the stands were examined separately for northern and southern side of the tree trunk. The presence of all types of lichen (crustose, foliose and fruticose) species were registered. Twenty-two lichen species in total were found in the experimental sites; six in P. abies stand, seven in B. pendula stand, nine in L.Ă—eurolepis stand and eighteen in P. trichocarpa stand. Most of the lichen species are common in Sweden. Although one red-listed lichen species, Alyxoria ochrocheila was found. The status of this lichen is near threatened (NT). The non-metric multidimensional scaling (NMDS) had been used for displaying the diversity of lichen communities. The study showed the highest lichen community diversity and species richness in the P. trichocarpa stand. The only one red-listed lichen species, A. ochrocheila was also found in this stand. The other non-native tree species stand (L.Ă—eurolepis) showed higher diversity and species richness than both stands of native tree species. The less lichen diverse and the poorest in lichens species was the P. abies stand. The diameter breast height was not significant for lichen richness in this study. Neither was the side of the tree on which the lichens were found. Investigated non-native tree species seem to have potential to increase biodiversity in production stands. Considering the bark complexity, fast growth and stand architecture, species like poplar may support ecological functions similar to those provided by great-dimension, old trees like oaks. It is recommended to continue the study in other parts of Sweden

    Supervised Identification of Writer\u27s Native Language Based on Their English Word Usage

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    In this paper, we investigate the possibility of constructing an automated tool for the writer\u27s first language detection based on a~document written in their second language. Since English is the contemporary lingua franca, commonly used by non-native speakers, we have chosen it to be the second language to study. In this paper, we examine English texts from computer science, a field related to mathematics. More generally, we wanted to study texts from a domain that operates with formal rules. We were able to achieve a high classification rate, about~90\%, using a relatively simple model (n-grams with logistic regression). We trained the model to distinguish twelve nationality groups/first languages based on our dataset. The classification mechanism was implemented using logistic regression with L1~regularisation, which performed well with sparse document-term data table. The experiment proved that we can use vocabulary alone to detect the first language with high accuracy

    Time Series Classification Using Images

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    This work is a contribution to the field of time series classification. We propose a novel method that transforms time series into multi-channel images, which are then classified using Convolutional Neural Networks as an at-hand classifier. We present different variants of the proposed method. Time series with different characteristics are studied in this paper: univariate, multivariate, and varying lengths. Several selected methods of time-series-to-image transformation are considered, taking into account the original series values, value changes (first differentials), and changes in value changes (second differentials). In the paper, we present an empirical study demonstrating the quality of time series classification using the proposed approach

    Apo-opsin exists in equilibrium between a predominant inactive and a rare highly active state

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    Bleaching adaptation in rod photoreceptors is mediated by apo-opsin, which activates phototransduction with effective activity 1

    Online learning of windmill time series using Long Short-term Cognitive Networks

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    Forecasting windmill time series is often the basis of other processes such as anomaly detection, health monitoring, or maintenance scheduling. The amount of data generated on windmill farms makes online learning the most viable strategy to follow. Such settings require retraining the model each time a new batch of data is available. However, update the model with the new information is often very expensive to perform using traditional Recurrent Neural Networks (RNNs). In this paper, we use Long Short-term Cognitive Networks (LSTCNs) to forecast windmill time series in online settings. These recently introduced neural systems consist of chained Short-term Cognitive Network blocks, each processing a temporal data chunk. The learning algorithm of these blocks is based on a very fast, deterministic learning rule that makes LSTCNs suitable for online learning tasks. The numerical simulations using a case study with four windmills showed that our approach reported the lowest forecasting errors with respect to a simple RNN, a Long Short-term Memory, a Gated Recurrent Unit, and a Hidden Markov Model. What is perhaps more important is that the LSTCN approach is significantly faster than these state-of-the-art models

    Thiomorpholino oligonucleotides as a robust class of next generation platforms for alternate mRNA splicing

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    Recent advances in drug development have seen numerous successful clinical translations using synthetic antisense oligonucleotides (ASOs). However, major obstacles, such as challenging large-scale production, toxicity, localization of oligonucleotides in specific cellular compartments or tissues, and the high cost of treatment, need to be addressed. Thiomorpholino oligonucleotides (TMOs) are a recently developed novel nucleic acid analog that may potentially address these issues. TMOs are composed of a morpholino nucleoside joined by thiophosphoramidate internucleotide linkages. Unlike phosphorodiamidate morpholino oligomers (PMOs) that are currently used in various splice-switching ASO drugs, TMOs can be synthesized using solid-phase oligonucleotide synthesis methodologies. In this study, we synthesized various TMOs and evaluated their efficacy to induce exon skipping in a Duchenne muscular dystrophy (DMD) in vitro model using H2K mdx mouse myotubes. Our experiments demonstrated that TMOs can efficiently internalize and induce excellent exon 23 skipping potency compared with a conventional PMO control and other widely used nucleotide analogs, such as 2′-O-methyl and 2′-O-methoxyethyl ASOs. Notably, TMOs performed well at low concentrations (5–20 nM). Therefore, the dosages can be minimized, which may improve the drug safety profile. Based on the present study, we propose that TMOs represent a new, promising class of nucleic acid analogs for future oligonucleotide therapeutic development

    Noninfectious complications of acute stroke and their impact on hospital mortality in patients admitted to a stroke unit in Warsaw from 1995 to 2015

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    Background Medical complications often worsen the prognosis after stroke. Our aim was to investigate the association between particular noninfectious complications and hospital mortality of acute stroke patients admitted to an urban Polish stroke center, and changes in their occurrence from 1995 to 2015. Methods This is a retrospective analysis of 5174 consecutive patients admitted for acute ischemic stroke or cerebral hemorrhage to a Polish urban stroke center between 1995 and 2015. The occurrence of complications was reported for years 1995–2000 (n=883), 2001–2006 (n=1567), 2006–2010 (n=1539) and 2011–2015 (n=1183). Odds ratios (OR) with 95% confidence interval (95% CI) for stroke unit death were calculated after adjustment for age, congestive heart failure (CHF), pre-existing disability, stroke type and baseline neurological deficit in three different time periods. Results Over time there was a significant decrease in the occurrence of myocardial infarction (MI) (2.2%, 1.4%, 1.0% and 0.3%, respectively), exacerbated CHF (4.6%, 5.1%, 2.6% and 2.0%) and deep vein thrombosis (DVT) (4.6%, 2.7%, 1.2% and 1.1%). Adjusted odds for stroke unit death were increased by myocardial infarction (MI) (OR 17.5, 95% CI: 8.5–35.7), exacerbated CHF (OR 15.0, 95% CI: 9.8–23.0), pulmonary embolism (PE) (OR 11.5, 95% CI: 6.1–21.6), gastrointestinal bleeding (OR 9.2, 95% CI: 4.4–18.9) and recurrent stroke (OR 5.4, 95% CI: 3.1–9.3). Conclusions Over the last two decades Polish urban stroke units may have achieved a significant reduction of the occurrence of some noninfectious complications (i.e. MI, exacerbated CHF and DVT). However, the list of conditions associated with stroke unit mortality includes not only MI and exacerbated CHF but also PE, gastrointestinal bleeding and recurrent stroke

    Autosomal recessive retinitis pigmentosa E150K opsin mice exhibit photoreceptor disorganization

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    The pathophysiology of the E150K mutation in the rod opsin gene associated with autosomal recessive retinitis pigmentosa (arRP) has yet to be determined. We generated knock-in mice carrying a single nucleotide change in exon 2 of the rod opsin gene resulting in the E150K mutation. This novel mouse model displayed severe retinal degeneration affecting rhodopsin’s stabilization of rod outer segments (ROS). Homozygous E150K (KK) mice exhibited early-onset retinal degeneration, with disorganized ROS structures, autofluorescent deposits in the subretinal space, and aberrant photoreceptor phagocytosis. Heterozygous (EK) mice displayed a delayed-onset milder retinal degeneration. Further, mutant receptors were mislocalized to the inner segments and perinuclear region. Though KK mouse rods displayed markedly decreased phototransduction, biochemical studies of the mutant rhodopsin revealed only minimally affected chromophore binding and G protein activation. Ablation of the chromophore by crossing KK mice with mice lacking the critical visual cycle protein LRAT slowed retinal degeneration, whereas blocking phototransduction by crossing KK mice with GNAT1-deficient mice slightly accelerated this process. This study highlights the importance of proper higher-order organization of rhodopsin in the native tissue and provides information about the signaling properties of this mutant rhodopsin. Additionally, these results suggest that patients heterozygous for the E150K mutation should be periodically reevaluated for delayed-onset retinal degeneration
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