Search results for "Stages"
showing 10 items of 217 documents
Trophic Requirements of the Sea Urchin Paracentrotus lividus Varies at Different Life Stages: Comprehension of Species Ecology and Implications for E…
2022
Investigations on trophic requirements of different life cycle stages of Paracentrotus lividus are crucial for the comprehension of species ecology and for its artificial rearing. The future success of echinoculture depends heavily on the development of suitable and cost-effective diets that are specifically designed to maximize somatic growth during the early life stages and gonadal production in the later stages. In this context, a considerable number of studies have recommended animal sources as supplements in sea urchin diets. However, with the exception of Fernandez and Boudouresque (2000), no studies have investigated the dietary requirements over the different life stages of the sea …
Automatic recognition of rapid eye movement (REM) sleep by artificial neural networks.
1995
Artificial neural networks are well known for their good performance in pattern recognition. Their suitability for detecting REM sleep periods on the basis of preprocessed EEG data in humans under clinical conditions was tested and their performance compared with the manual evaluation. A single channel of the EEG signal was analysed in time periods of 20 s and preprocessed into a vector of six real numbers, which served as input to the network. EOG and EMG information was ignored. Backpropagation was used as a learning rule for the network, which consisted of 12 neurons and 39 synapses. Training datasets were put together from the input vectors and the corresponding sleep stages were scored…
Automatic Sleep Stage Identification with Time Distributed Convolutional Neural Network
2021
Polysomnography (PSG), the gold standard for sleep stage classification, requires a sleep expert for scoring and is both resource-intensive and expensive. Many researchers currently focus on the real-time classification of the sleep stages based on biomedical signals, such as Electroencephalograph (EEG) and electrooculography (EOG). However, most of the research work is based on machine learning models with multiple signal inputs or hand-engineered features requiring prior knowledge of the sleep domain. We propose a novel encoded Time-Distributed Convolutional Neural Network (TDConvNet) to automatically classify sleep stages based on a single raw PSG signal. The TDConvNet can infer sleep st…
No Effects of Pulsed High-Frequency Electromagnetic Fields on Heart Rate Variability during Human Sleep<sup>1</sup>
1998
The influence of pulsed high-frequency electromagnetic fields emitted by digital mobile radio telephones on heart rate during sleep in healthy humans was investigated. Beside mean RR interval and total variability of RR intervals based on calculation of the standard deviation, heart rate variability was assessed in the frequency domain by spectral power analysis providing information about the balance between the two branches of the autonomic nervous system. For most parameters, significant differences between different sleep stages were found. In particular, slow-wave sleep was characterized by a low ratio of low- and high-frequency components, indicating a predominance of the parasympathe…
Impact of an oral appliance on obstructive sleep apnea severity, quality of life, and biomarkers
2017
OBJECTIVE/HYPOTHESIS To investigate outcomes including efficacy, quality of life, and levels of inflammatory markers of a mandibular advancement device (MAD) for moderate-to-severe obstructive sleep apnea (OSA). STUDY DESIGN Case-control study. METHODS Patients with apnea-hypopnea index (AHI) ≥ 15/hr who only accepted MAD therapy (study group) or who refused any treatment (control group) were recruited. At baseline and at 6 months, polysomnography, Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire (FOSQ), C-reactive protein (CRP), interleukin 1β, interleukin 6, and tumor necrosis factor α (TNF-α) were assessed in both groups. RESULTS At baseline, the study group (n …
EEG-responses caused by environmental noise during sleep their relationships to exogenic and endogenic influences.
1978
Abstract At a certain level of intensity acoustical stimuli occurring during the night lead to sleep disorders. Whereas presumed after-effects (decrease of performance, functional and organic diseases) can as yet not be related to noise, it is evident that the primary effects which can be recorded immediately after stimulus onset are caused by noise. Because of the small number of experimental trials carried out in different investigations, the results of each single paper can only be tentative. Therefore — concerning awakening reactions and reactions less than a change of at least one sleep stage — the data from publications of comparable method and evaluation have been summarised. With th…
Being successful in the world of narrow opportunities: transmission patterns of the trematode Ichthyocotylurus pileatus.
2009
SUMMARYParasites with complex life cycles face 2 major challenges for transmission in northern latitudes. They have to cope with the general unpredictability associated with the series of transmission events required for completion of the cycle, and transmission has to be completed within a narrow temporal window because of strong seasonality. Despite this, some parasites show high transmission success, suggesting the operation of effective transmission mechanisms. We explored the transmission of Ichthyocotylurus pileatus (Trematoda) from its snail (Valvata macrostoma) to fish (Perca fluviatilis) hosts by examining some key characteristics in the dynamics of the cercarial emergence from sna…
Identity Problems, Ego Strengths, Perceived Stress, and Adjustment During Contextual Changes at University
2017
ABSTRACTWe present a 2-year time-lag study in which Canadian and Spanish students’ perceptions of stress, identity problems, and psychosocial maturity (ego strengths) were examined in relation to academic, social, and personal-emotional adjustment to university under different conditions of macro-environmental disruption (i.e., academic and economic) and no disruption (stability). In the academic disturbance context, students reported increased stress and the economic disruption situation was associated with greater identity problems. The expected relationships were found among the variables in the study. Students reported greater social maladjustment at university related to economic disru…
3D Morphology, ultrastructure and development of Ceratomyxa puntazzi stages: first insights into the mechanisms of motility and budding in the Myxozo…
2012
Free, amoeboid movement of organisms within media as well as substrate-dependent cellular crawling processes of cells and organisms require an actin cytoskeleton. This system is also involved in the cytokinetic processes of all eukaryotic cells. Myxozoan parasites are known for the disease they cause in economical important fishes. Usually, their pathology is related to rapid proliferation in the host. However, the sequences of their development are still poorly understood, especially with regard to pre-sporogonic proliferation mechanisms. The present work employs light microscopy (LM), electron microscopy (SEM, TEM) and confocal laser scanning microscopy (CLSM) in combination with specific…
Characterization of activated sludge settling properties with a sludge collapse-acceleration stage
2019
Abstract The sedimentability of the activated sludge can be affected by the presence of a large variety of coagulants and polymers from a previous physical-chemical process. In this paper, the activated sludge settling process in industrial wastewater treatment plants where the sludge does not settle in a conventional way is studied. The two observed constant hindered settling velocity stages and the instant the intermediate sludge acceleration period occurs are described. A variation of the Richardson and Zaki model is used to characterize the two stages of constant settling velocity. The concentration of suspended solids, where a sudden decrease of hindered settling velocity was observed,…