482 research outputs found
Method of low-cycle fatigue test results processing
There is considered the method of proceeding during elaboration of low-cycle fatigue test results of metals. Presented method enables to determine the material data in various periods of fatigue life. The results obtained with the use of proposed method allow taking into account during fatigue life calculations as the visible changes of cyclic properties of material. The above is of special importance in the case of material characterized by the absence of stabilization period.Подано новий метод аналізу результатів мaлoциклoвих випробувань металів на втому, який дає змогу визначити характеристики матеріалів на різних стадіях втоми. Отримані дані можуть бути використані для розрахунків втомної довговічності елементів конструкцій.Представлен новый метод анализа результатов мaлoциклoвых испытаний металлов на усталость, который позволяет определить характеристики материалов на разных стадиях усталости. Полученные данные могут быть использованы для расчета усталостной долговечности элементов конструкций
Application of one and two-dimensional hydrodynamic models to rio Grande-MG river basin
O presente artigo faz uma análise da calibração do modelo hidrodinâmico uni e
bidimensional aplicado à bacia do Rio Grande
, na localidade da cidade de Ribeirão Vermelho em
Minas Gerais
. O software SOBE
K foi utilizado para a implementação dos modelos
que foram devidamente calibrados.
Apresenta-se a discretização utilizada para
Representar adequadamente uma ponte
rodoferroviária inundável, uma vez que a
utilização de uma única estrutura não se revelou
suficiente para simular as
características
de escoamento da forma desejada.
Além disso, foram
analisados em detalhe os métodos que o software SOBEK
possui para
transmitir
as informações
entre os modelos uni
e bidimensional.
Com o objetivo de
aprimorar
a modelagem
foram utilizados
artifícios do software
para
determinar
a partir de qual elevação os modelos 1D e 2D seriam
utilizados.
Os resultados indicam que a
consideração do escoamento bidimensional
favorece o desempenho do modelo, visto que proporciona um maior detalhamento na representação da regiãoThis paper analyzes the calibration of a one and two
-
dimensional hydrodynamic
model of Rio Grande
-
MG river basin, near the city of Ribeirão Vermelho
in
Minas Gerais.
The
SOBEK software was used for the implemen
tation of the models that was properly calibrated.
The
discretization to adequately represent flooding over a road
-
railway bridge is characterized, since the
use of a unique structure it was not sufficient to simulate the flow characteristics as desired near the
bridge. In addition available software options
for sharing of data between one and two
-
dimensional
models are analyzed.
In order t
o
improve
the modeling
results
proper software options were used to
determine the water surface elevation to activate the 1D and 2D modules. Results indicate that
considerat
ion of two
-
dimensional flow improve the model performance, since it provides a more
detailed representation of the flooded are
Electrocorticography is superior to subthalamic local field potentials for movement decoding in Parkinson’s disease
Brain signal decoding promises significant advances in the development of clinical brain computer interfaces (BCI). In Parkinson's disease (PD), first bidirectional BCI implants for adaptive deep brain stimulation (DBS) are now available. Brain signal decoding can extend the clinical utility of adaptive DBS but the impact of neural source, computational methods and PD pathophysiology on decoding performance are unknown. This represents an unmet need for the development of future neurotechnology. To address this, we developed an invasive brain-signal decoding approach based on intraoperative sensorimotor electrocorticography (ECoG) and subthalamic LFP to predict grip-force, a representative movement decoding application, in 11 PD patients undergoing DBS. We demonstrate that ECoG is superior to subthalamic LFP for accurate grip-force decoding. Gradient boosted decision trees (XGBOOST) outperformed other model architectures. ECoG based decoding performance negatively correlated with motor impairment, which could be attributed to subthalamic beta bursts in the motor preparation and movement period. This highlights the impact of PD pathophysiology on the neural capacity to encode movement vigor. Finally, we developed a connectomic analysis that could predict grip-force decoding performance of individual ECoG channels across patients by using their connectomic fingerprints. Our study provides a neurophysiological and computational framework for invasive brain signal decoding to aid the development of an individualized precision-medicine approach to intelligent adaptive DBS
Cultivation of a novel cold-adapted nitrite oxidizing betaproteobacterium from the Siberian Arctic
Permafrost-affected soils of the Siberian Arctic were investigated with regard to identification of nitrite oxidizing bacteria active at low temperature. Analysis of the fatty acid profiles of enrichment cultures grown at 4°C, 10°C and 17°C revealed a pattern that was different from that of known nitrite oxidizers but was similar to fatty acid profiles of Betaproteobacteria. Electron microscopy of two enrichment cultures grown at 10°C showed prevalent cells with a conspicuous ultrastructure. Sequence analysis of the 16S rRNA genes allocated the organisms to a so far uncultivated cluster of the Betaproteobacteria, with Gallionella ferruginea as next related taxonomically described organism. The results demonstrate that a novel genus of chemolithoautotrophic nitrite oxidizing bacteria is present in polygonal tundra soils and can be enriched at low temperatures up to 17°C. Cloned sequences with high sequence similarities were previously reported from mesophilic habitats like activated sludge and therefore an involvement of this taxon in nitrite oxidation in nonarctic habitats is suggested. The presented culture will provide an opportunity to correlate nitrification with nonidentified environmental clones in moderate habitats and give insights into mechanisms of cold adaptation. We propose provisional classification of the novel nitrite oxidizing bacterium as 'Candidatus Nitrotoga arctica'
Differences in Performance Assessments Conducted Indoors and Outdoors in Professional Cyclists
Purpose: The purpose of this study was to assess the relationship between typical performance tests amongst elite and professional cyclists when conducted indoors and outdoors. Methods: 14 male cyclists of either UCI Continental or UCI World Tour level (mean ± SD: age 20.9 ± 2.8 y, mass 68.13 ± 7.25 kg) were recruited to participate in 4 test sessions (2 test sessions indoors, 2 test sessions outdoors) within a 14-day period, consisting of maximum mean power (MMP) testing for durations of 60s, 180s, 300s and 840s. Results: Across all MMP test durations, the trimmed mean power was higher outdoors compared to indoor testing (p < 0.05). Critical Power (CP) was higher outdoors compared to indoors (+19 W, p = 0.005) whilst no difference was observed for the work capacity above CP (W’). Self-selected cadence was 6 rev∙min-1 higher indoors versus outdoors for test durations of 60s (p = 0.038) and 300s (p = 0.002). Conclusions: These findings suggest that maximal power testing in indoor and outdoor settings cannot be used interchangeably. Furthermore, there was substantial individual variation in the difference between indoor and outdoor MMPs, across all time durations, further highlighting the difficulty of translating results from indoor testing to outdoor, on an individual level in elite populations
Assumptions behind grammatical approaches to code-switching: when the blueprint is a red herring
Many of the so-called ‘grammars’ of code-switching are based on various underlying assumptions, e.g. that informal speech can be adequately or appropriately described in terms of ‘‘grammar’’; that deep, rather than surface, structures are involved in code-switching; that one ‘language’ is the ‘base’ or ‘matrix’; and that constraints derived from existing data are universal and predictive. We question these assumptions on several grounds. First, ‘grammar’ is arguably distinct from the processes driving speech production. Second, the role of grammar is mediated by the variable, poly-idiolectal repertoires of bilingual speakers. Third, in many instances of CS the notion of a ‘base’ system is either irrelevant, or fails to explain the facts. Fourth, sociolinguistic factors frequently override ‘grammatical’ factors, as evidence from the same language pairs in different settings has shown. No principles proposed to date account for all the facts, and it seems unlikely that ‘grammar’, as conventionally conceived, can provide definitive answers. We conclude that rather than seeking universal, predictive grammatical rules, research on CS should focus on the variability of bilingual grammars
Answering Non-Monotonic Queries in Relational Data Exchange
Relational data exchange is the problem of translating relational data from a
source schema into a target schema, according to a specification of the
relationship between the source data and the target data. One of the basic
issues is how to answer queries that are posed against target data. While
consensus has been reached on the definitive semantics for monotonic queries,
this issue turned out to be considerably more difficult for non-monotonic
queries. Several semantics for non-monotonic queries have been proposed in the
past few years. This article proposes a new semantics for non-monotonic
queries, called the GCWA*-semantics. It is inspired by semantics from the area
of deductive databases. We show that the GCWA*-semantics coincides with the
standard open world semantics on monotonic queries, and we further explore the
(data) complexity of evaluating non-monotonic queries under the
GCWA*-semantics. In particular, we introduce a class of schema mappings for
which universal queries can be evaluated under the GCWA*-semantics in
polynomial time (data complexity) on the core of the universal solutions.Comment: 55 pages, 3 figure
Subthalamic Nucleus and Sensorimotor Cortex Activity During Speech Production
The sensorimotor cortex is somatotopically organized to represent the vocal tract articulators such as lips, tongue, larynx, and jaw. How speech and articulatory features are encoded at the subcortical level, however, remains largely unknown. We analyzed LFP recordings from the subthalamic nucleus (STN) and simultaneous electrocorticography recordings from the sensorimotor cortex of 11 human subjects (1 female) with Parkinson´s disease during implantation of deep-brain stimulation (DBS) electrodes while they read aloud three-phoneme words. The initial phonemes involved either articulation primarily with the tongue (coronal consonants) or the lips (labial consonants). We observed significant increases in high-gamma (60?150 Hz) power in both the STN and the sensorimotor cortex that began before speech onset and persisted for the duration of speech articulation. As expected from previous reports, in the sensorimotor cortex, the primary articulators involved in the production of the initial consonants were topographically represented by high-gamma activity. We found that STN high-gamma activity also demonstrated specificity for the primary articulator, although no clear topography was observed. In general, subthalamic high-gamma activity varied along the ventral?dorsal trajectory of the electrodes, with greater high-gamma power recorded in the dorsal locations of the STN. Interestingly, the majority of significant articulator-discriminative activity in the STN occurred before that in sensorimotor cortex. These results demonstrate that articulator-specific speech information is contained within high-gamma activity of the STN, but with different spatial and temporal organization compared with similar information encoded in the sensorimotor cortex.Fil: Chrabaszcz, Anna. University of Pittsburgh; Estados UnidosFil: Neumann, Wolf Julian. Universität zu Berlin; AlemaniaFil: Stretcu, Otilia. University of Pittsburgh; Estados UnidosFil: Lipski, Witold J.. University of Pittsburgh; Estados UnidosFil: Dastolfo Hromack, Christina A.. University of Pittsburgh; Estados UnidosFil: Bush, Alan. University of Pittsburgh; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Wang, Dengyu. Tsinghua University; China. University of Pittsburgh; Estados UnidosFil: Crammond, Donald J.. University of Pittsburgh; Estados UnidosFil: Shaiman, Susan. University of Pittsburgh; Estados UnidosFil: Dickey, Michael W.. University of Pittsburgh; Estados UnidosFil: Holt, Lori L.. University of Pittsburgh; Estados UnidosFil: Turner, Robert S.. University of Pittsburgh; Estados UnidosFil: Fiez, Julie A.. University of Pittsburgh; Estados UnidosFil: Richardson, R. Mark. University of Pittsburgh; Estados Unido
Photoinduced transformation of waste-derived soluble bio-based substances
[EN] Waste-derived, soluble bin-based substances (SBO), are effective low-cost photosensitizers that could find application in pollutant photodegradation. For this reason, it is important to understand if and to what extent irradiation could modify their properties. The exposure of SBO to simulated sunlight induced important spectral and structural modifications. Both the whole material and its acid-soluble fraction were characterized, highlighting several properties in common with humic and fulvic substances, including absorption spectra, specific absorbance and fluorescence behavior. The latter was described with a three-component model using PARAFAC analysis. Irradiation induced SBO photobleaching, but the absorbance of the acid-soluble fraction increased with irradiation. This finding suggests a progressive photochemical solubilization of SBO, which is confirmed by the increase of the carboxylic groups. In addition to absorbance, the fluorescence of whole SBO was also decreased by irradiation, thereby suggesting that both chromophores and fluorophores were photodegraded. The increasingly hydrophilic character given to SBO by irradiation also accounted for the photoinduced decrease of the surfactant properties of the material. (C) 2015 Elsevier B.V. All rights reserved.This work was funded by the 7thFP IRSES-2010-269128-EnvironBos Marie Curie Action and by Ministero delle Politiche Agricole e Forestali (Agrienergia project). The authors are grateful to the following private and/or public Italian institutions: (a) Acea Pinerolese Spa in Pinerolo (TO) for supplying the SBO sourcing materials; (b) Studio Chiono ed Associati in Rivarolo Canavese (TO) for making available pilot equipment and services for the production of the SBO.Avetta, P.; Berto, S.; Bianco Prevot, A.; Minella, M.; Montoneri, E.; Persico, D.; Vione, D.... (2015). Photoinduced transformation of waste-derived soluble bio-based substances. Chemical Engineering Journal. 274:247-255. https://doi.org/10.1016/j.cej.2015.03.126S24725527
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