19 results on '"Maria Dimitropoulou"'
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2. Analysis of Scheduling Schemes in Wireless Powered Backscatter Communication Networks with Spatial Randomness.
- Author
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Maria Dimitropoulou, M. Majid Butt, Constantinos Psomas, Ahlem Khlass, and Ioannis Krikidis
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- 2023
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3. Opportunistic Beamforming with Beam Selection in IRS-aided Communications.
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Maria Dimitropoulou, Constantinos Psomas, and Ioannis Krikidis
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- 2022
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4. k-th Best Device Selection for Scheduling in Wireless Powered Communication Networks.
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Maria Dimitropoulou, Constantinos Psomas, and Ioannis Krikidis
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- 2020
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5. Similar Conceptual Mapping of Novel Objects in Mixed‐ and Single‐Language Contexts in Fluent Basque‐Spanish Bilinguals
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Guillaume Thierry, Maria Dimitropoulou, Eneko Antón, and Jon Andoni Duñabeitia
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Linguistics and Language ,Government (linguistics) ,Cognition ,Conceptual mapping ,Language acquisition ,Psychology ,Neuroscience of multilingualism ,Language and Linguistics ,Linguistics ,Education - Abstract
This research has been partially funded by grant PSI2015‐65689‐P from the Spanish Government and grant PGC2018‐097145‐B‐I00 from the Agencia Estatal de Investigacion
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- 2020
6. Right atrial thrombus mimicking cardiac tumor in a neonate
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Maria Dimitropoulou, Dimitrios Bobos, Meletios A. Kanakis, Theofili Kousi, Ioanne Sofianidou, Nicholas Giannopoulos, Afroditi Karafotia, and George Samanidis
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medicine.medical_specialty ,Medicine (General) ,cardiac tumor ,right atrium ,R5-920 ,Clinical Images ,Internal medicine ,medicine ,Thrombus ,Cardiac Tumors ,business.industry ,General Medicine ,medicine.disease ,Right Atrial Thrombus ,medicine.anatomical_structure ,thrombus ,Clinical Image ,Cardiac mass ,Cardiology ,cardiovascular system ,Right atrium ,Medicine ,Surgical excision ,neonate ,business - Abstract
Does the cardiac mass should be operated in neonates? When diagnosis of cardiac tumor or mass has been made, the surgical excision should not be delayed for prevention of life‐treating complications, Does the cardiac mass should be operated in neonates? When diagnosis of cardiac tumor or mass has been made, the surgical excision should not be delayed for prevention of life‐treating complications.
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- 2020
7. Generalized Selection in Wireless Powered Networks with Non-Linear Energy Harvesting
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Constantinos Psomas, Ioannis Krikidis, and Maria Dimitropoulou
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Signal Processing (eess.SP) ,FOS: Computer and information sciences ,extreme value theory ,Computer science ,Distributed computing ,Computer Science - Information Theory ,wireless power transfer ,050801 communication & media studies ,Scheduling (computing) ,0508 media and communications ,order statistics ,FOS: Electrical engineering, electronic engineering, information engineering ,Wireless ,Wireless power transfer ,Electrical and Electronic Engineering ,Electrical Engineering and Systems Science - Signal Processing ,outage probability ,k-th best selection ,business.industry ,Information Theory (cs.IT) ,05 social sciences ,Transmitter ,Telecommunications network ,Channel state information ,business ,Realization (systems) ,Energy harvesting - Abstract
The rapid growth of the so-called Internet of Things is expected to significantly expand and support the deployment of resource-limited devices. Therefore, intelligent scheduling protocols and technologies such as wireless power transfer, are important for the efficient implementation of these massive low-powered networks. This paper studies the performance of a wireless powered communication network, where multiple batteryless devices harvest radio-frequency from a dedicated transmitter in order to communicate with a common information receiver (IR). We investigate several novel selection schemes, corresponding to different channel state information requirements and implementation complexities. In particular, each scheme schedules the $k$-th best device based on: a) the end-to-end (e2e) signal-to-noise ratio (SNR), b) the energy harvested at the devices, c) the uplink transmission to the IR, and d) the conventional/legacy max-min selection policy. We consider a non-linear energy harvesting (EH) model and derive analytical expressions for the outage probability of each selection scheme by using tools from high order statistics. %Our results show that, the performance of all the proposed schemes converges to an error floor due to the saturation effects of the considered EH model. Moreover, an asymptotic scenario in terms of the number of devices is considered and, by applying extreme value theory, the system's performance is evaluated. We derive a complete analytical framework that provides useful insights for the design and realization of such networks.
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- 2021
8. The role of form in morphological priming: Evidence from bilinguals
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Maria Dimitropoulou, Kevin Diependaele, Joanna Morris, and Jon Andoni Duñabeitia
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DECOMPOSITION ,Linguistics and Language ,VISUAL WORD RECOGNITION ,PSYCHOLINGUISTIC STATISTICS ,Bilingualism ,Stem priming ,Morphological decomposition ,Experimental and Cognitive Psychology ,Languages and Literatures ,Language and Linguistics ,Education ,MASKED REPETITION ,Masked morphological priming ,Form overlap ,PROGRAM ,Lexical decision task ,SEMANTIC TRANSPARENCY ,Cognate ,Neuroscience of multilingualism ,LANGUAGE COMPREHENSION ,Visual word recognition ,Linguistics ,Cognates ,TIME-COURSE ,Time course ,MORPHO-ORTHOGRAPHIC SEGMENTATION ,TRANSLATION ,Psychology ,Priming (psychology) - Abstract
This article explores how bilinguals perform automatic morphological decomposition processes, focusing on within- and cross-language masked morphological priming effects. In Experiment 1, unbalanced Spanish (L1) – English (L2) bilingual participants completed a lexical decision task on English targets that could be preceded by morphologically related or unrelated derived masked English and Spanish prime words. The cognate status of the masked Spanish primes was manipulated, in order to explore to what extent form overlap mediates cross-language morphological priming. In Experiment 2, a group of balanced native Basque-Spanish speakers completed a lexical decision task on Spanish targets preceded by morphologically related or unrelated Basque or Spanish masked primes. In this experiment, a large number of items was tested and the cognate status was manipulated according to a continuous measure of orthographic overlap, allowing for a fine-grained analysis of the role of form overlap in cross-language morphological priming. Results demonstrated the existence of between- language masked morphological priming, which was exclusively found for cognate prime-target pairs. Furthermore, the results from balanced and unbalanced bilinguals were highly similar showing that proficiency in the two languages at test does not seem to modulate the pattern of data. These results are correctly accounted for by mechanisms of early morpho-orthographic decomposition that do not necessarily imply an automatic translation of the prime. In contrast, other competing accounts that are based on translation processes do not seem able to capture the present results.
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- 2013
9. The Influence of Reading Expertise in Mirror-Letter Perception: Evidence From Beginning and Expert Readers
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Jon Andoni Duñabeitia, Maria Dimitropoulou, Manuel Carreiras, and Adelina Estévez
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Visual perception ,Cognitive Neuroscience ,media_common.quotation_subject ,05 social sciences ,Eye movement ,Experimental and Cognitive Psychology ,050105 experimental psychology ,Linguistics ,Lateralization of brain function ,Education ,03 medical and health sciences ,0302 clinical medicine ,Reading (process) ,Perception ,Word recognition ,Developmental and Educational Psychology ,Natural (music) ,0501 psychology and cognitive sciences ,10. No inequality ,Psychology ,030217 neurology & neurosurgery ,Word (group theory) ,media_common ,Cognitive psychology - Abstract
The visual word recognition system recruits neuronal systems originally developed for object perception which are characterized by orientation insensitivity to mirror reversals. It has been proposed that during reading acquisition beginning readers have to “unlearn” this natural tolerance to mirror reversals in order to efficiently discriminate letters and words. Therefore, it is supposed that this unlearning process takes place in a gradual way and that reading expertise modulates mirror-letter discrimination. However, to date no supporting evidence for this has been obtained. We present data from an eye-movement study that investigated the degree of sensitivity to mirror-letters in a group of beginning readers and a group of expert readers. Participants had to decide which of the two strings presented on a screen corresponded to an auditorily presented word. Visual displays always included the correct target word and one distractor word. Results showed that those distractors that were the same as the target word except for the mirror lateralization of two internal letters attracted participants' attention more than distractors created by replacement of 2 internal letters. Interestingly, the time course of the effects was found to be different for the 2 groups, with beginning readers showing a greater tolerance (decreased sensitivity) to mirror-letters than expert readers. Implications of these findings are discussed within the framework of preceding evidence showing how reading expertise modulates letter identification.
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- 2013
10. The Electrophysiology of the Bilingual Brain
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Margaret Gillon Dowens, Jon Andoni Duñabeitia, Nicola Molinaro, Clara D. Martin, and Maria Dimitropoulou
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medicine.diagnostic_test ,media_common.quotation_subject ,Cognition ,Electroencephalography ,Sentence processing ,Comprehension ,Event-related potential ,Reading (process) ,medicine ,Written language ,Psychology ,Neuroscience of multilingualism ,Cognitive psychology ,media_common - Abstract
In this chapter, we focus on how bilinguals cope with reading individual words and sentences in their different languages, and on how electroencephalographic (EEG) recordings could be used to explore the time course of the cognitive processes underlying bilingual comprehension of visually delivered linguistic stimuli. Event-related brain potentials (ERPs) comparing native and nonnative written language processing have been repeatedly used to reveal effects that occur very early in the stream of processing and that are essential for a correct understanding of the cognitive processes leading to efficient word and sentence processing by multilingual readers. We summarize the most relevant studies from this field and offer a list of recommendations for researchers aiming at using EEG recordings as a tool to investigate the complex pattern of feed-forward and feedback interactive activations flowing along the visual recognition system that ultimately lead to efficient bilingual reading.
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- 2016
11. Phonology by itself: Masked phonological priming effects with and without orthographic overlap
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Maria Dimitropoulou, Jon Andoni Duñabeitia, and Manuel Carreiras
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Visual word recognition ,Orthographic projection ,Experimental and Cognitive Psychology ,Phonology ,Stimulus (physiology) ,Psychology ,Neuroscience of multilingualism ,Phonological code ,Linguistics - Abstract
The activation of the phonological code plays a central role in visual word recognition. However, it is still unclear how this activation is integrated within this mainly bottom-up process. In the present masked priming study we combined Greek and Spanish, two languages with common phonemes and partially overlapping graphemes to investigate this issue. Greek-Spanish bilinguals performed lexical decisions on Greek and Spanish targets, briefly preceded by either phonologically related or orthographically and phonologically related prime words of the nontarget language. Results revealed significant bidirectional cross-script masked phonological priming effects which disappeared under the influence of nearly overlapping orthographic representations. This pattern of effects suggests that there is fast and automatic language nonselective activation of the phonological code during the initial stages of visual word recognition but that this is clearly dependent on the orthographic properties of the input stimulus...
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- 2011
12. Influence of prime lexicality, frequency, and pronounceability on the masked onset priming effect
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Jon Andoni Duñabeitia, Maria Dimitropoulou, and Manuel Carreiras
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Male ,Masking (art) ,Universities ,Physiology ,Experimental and Cognitive Psychology ,Pronunciation ,Lexicon ,Vocabulary ,Prime (symbol) ,Phonetics ,Physiology (medical) ,Reaction Time ,Humans ,Speech ,Students ,General Psychology ,computer.programming_language ,Psycholinguistics ,Cognition ,General Medicine ,Linguistics ,Semantics ,Word lists by frequency ,Neuropsychology and Physiological Psychology ,Pattern Recognition, Visual ,Female ,Lexico ,Cues ,Psychology ,Perceptual Masking ,computer - Abstract
The present study investigates the origins of the masked onset priming effect (MOPE). There are two alternative interpretations that account for most of the evidence reported on the MOPE, so far. The speech planning account (SP) identifies the locus of the MOPE in the preparation of the speech response. In contrast, the dual-route theory proposes that the effect arises as a result of the processing of the prime by the nonlexical route. In a series of masked onset priming word naming experiments we test the validity of these accounts by manipulating the primes’ frequency, their lexical status, and pronounceability. We found consistent MOPEs of similar magnitude with high- and low-frequency prime words as well as with pronounceable nonwords. Contrarily, when primes consisted of unpronounceable consonantal strings the effect disappeared, suggesting that pronounceability of the prime is a prerequisite for the emergence of the MOPE. These results are in accordance with the predictions of the SP account. The pattern of effects obtained in the present study further defines the origins of the MOPE.
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- 2010
13. A standardized set of 260 pictures for Modern Greek: Norms for name agreement, age of acquisition, and visual complexity
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Panagiotis Blitsas, Maria Dimitropoulou, Manuel Carreiras, and Jon Andoni Duñabeitia
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Psycholinguistics ,Greece ,Standardization ,Computer science ,Process (engineering) ,Modern Greek ,Experimental and Cognitive Psychology ,Language Development ,Linguistics ,Young Adult ,Greek language ,Age of Acquisition ,Arts and Humanities (miscellaneous) ,Reference Values ,Visual Perception ,Developmental and Educational Psychology ,Selection (linguistics) ,Humans ,Normative ,Psychology (miscellaneous) ,Set (psychology) ,Algorithms ,General Psychology - Abstract
The appropriate selection of both pictorial and linguistic experimental stimuli requires a previous languagespecific standardization process of the materials across different variables. Considering that such normative data have not yet been collected for Modern Greek, in this study normative data for the color version of the Snodgrass and Vanderwart picture set (Rossion & Pourtois, 2004) were collected from 330 native Greek adults. Participants named the pictures (providing name agreement ratings) and rated them for visual complexity and age of acquisition. The obtained measures represent a useful tool for further research on Greek language processing and constitute the first picture normative study for this language. The picture norms from this study and previous ones may be downloaded from brm.psychonomic-journals.org/content/supplemental.
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- 2009
14. Generalized seizures and transient contralateral hemiparesis following retrobulbar anesthesia: a case report
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Dettoraki, Maria Dimitropoulou, Chrisafoula Nomikarios, Nikolaos and Moschos, Marilita M. Brouzas, Dimitrios
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genetic structures ,sense organs ,eye diseases - Abstract
Background: Retrobulbar block is a local anesthetic technique widely used for intraocular surgery. Although retrobulbar anesthesia is considered to be relatively safe, a number of serious adverse events have been reported. To our knowledge, immediate onset of generalized seizures with contralateral hemiparesis after retrobulbar anesthesia has not been reported. Case presentation: A 62-year-old Caucasian healthy male with a right eye retinal detachment was admitted for pars plana vitrectomy. During retrobulbar anesthesia with ropivacaine and before needle withdrawal, the patient developed twitching of the face which rapidly progressed to generalized tonic-clonic seizures. Arterial oxygen saturation decreased to 75 %. Chin lift was performed and 100 % oxygen was administrated via face mask, which increased saturation to 99 %. Midazolam 2 mg was administrated intravenously to control seizures. After cessation of seizures, left-sided hemiparesis was evident. Brain computed tomography and electroencephalogram were normal 3 h later. The patient underwent pars plana vitrectomy under general anesthesia 4 days later. Conclusion: Serious complications of local anesthesia for ophthalmic surgery are uncommon. We present a case in which generalized tonic-clonic seizures developed during retrobulbar anesthesia, followed by transient contralateral hemiparesis. The early onset of seizures indicated intra-arterial injection of the anesthetic. Our case suggested the need for close monitoring during the performance of retrobulbar anesthesia and the presence of well-trained personnel for early recognition and immediate management of the complications.
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- 2015
15. Differential Sensitivity of Letters, Numbers, and Symbols to Character Transpositions
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Jonathan Grainger, Juan A. Hernández, Maria Dimitropoulou, Jon Andoni Duñabeitia, Manuel Carreiras, Melmi, Jean-Baptiste, Laboratoire de psychologie cognitive (LPC), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Basque Foundation for Science (IKERBASQUE), Basque Foundation for Science (Ikerbasque), Basque Center on Cognition Brain and Language [Gipuzkoa, Espagne] (BCBL), Departamento de Lengua Vasca y Comunicación, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), and Ikerbasque - Basque Foundation for Science
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Adult ,Male ,Cognitive Neuroscience ,Speech recognition ,media_common.quotation_subject ,Stimulus (physiology) ,Referent ,050105 experimental psychology ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Perception ,Reaction Time ,Humans ,0501 psychology and cognitive sciences ,media_common ,Communication ,business.industry ,05 social sciences ,Numerical digit ,Pattern Recognition, Visual ,Reading ,[SCCO.PSYC]Cognitive science/Psychology ,Human visual system model ,[SCCO.PSYC] Cognitive science/Psychology ,Female ,business ,Psychology ,Photic Stimulation ,030217 neurology & neurosurgery - Abstract
This study was designed to explore whether the human visual system has different degrees of tolerance to character position changes for letter strings, digit strings, and symbol strings. An explicit perceptual matching task was used (same–different judgment), and participants' electrophysiological activity was recorded. Materials included trials in which the referent stimulus and the target stimulus were identical or differed either by two character replacements or by transposing two characters. Behavioral results showed clear differences in the magnitude of the transposed-character effect for letters as compared with digit and symbol strings. Electrophysiological data confirmed this observation, showing an N2 character transposition effect that was only present for letter strings. An earlier N1 transposition effect was also found for letters but was absent for symbols and digits, whereas a later P3 effect was found for all types of string. These results provide evidence for a position coding mechanism that is specific to letter strings, that was most prominent in an epoch between 200 and 325 msec, and that operates in addition to more general-purpose position coding mechanisms.
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- 2012
16. Transliteration and transcription effects in biscriptal readers: the case of Greeklish
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Maria Dimitropoulou, Manuel Carreiras, and Jon Andoni Duñabeitia
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Psycholinguistics ,Greece ,Latin script ,Modern Greek ,Experimental and Cognitive Psychology ,Linguistics ,Arts and Humanities (miscellaneous) ,Transcription (linguistics) ,Writing system ,Reading ,Phonetics ,Developmental and Educational Psychology ,Lexical decision task ,Transliteration ,Reaction Time ,Humans ,Greeklish ,Psychology ,Priming (psychology) ,Language - Abstract
In order to overcome limitations associated with script incompatibilities Greek users of the Internet have developed Greeklish, a transliterated version of Modern Greek using Roman characters. The representational status of this artificial writing system was examined in two masked priming lexical decision experiments using Greeklish primes with different degrees of graphemic overlap with their corresponding Greek targets. Results suggested that Greeklish primes were effectively processed and transliterated to their Greek counterparts. Larger masked priming effects were found as a function of increased prime-target graphemic overlap. Interestingly, these Greeklish priming effects were in all cases of smaller magnitude than the pure Greek identity priming effect. Our findings revealed that extensive experience with a recently developed artificial writing system leads to its non-effortful processing, but that even for highly experienced Greeklish users the Greeklish-to-Greek conversion is modulated by the graphemic properties of the input stimulus.
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- 2011
17. Masked translation priming effects with low proficient bilinguals
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Jon Andoni Duñabeitia, Maria Dimitropoulou, and Manuel Carreiras
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Adult ,Male ,Experimental psychology ,Decision Making ,Experimental and Cognitive Psychology ,Multilingualism ,Vocabulary ,Young Adult ,Arts and Humanities (miscellaneous) ,Lexical decision task ,Humans ,Language translation ,Students ,Neuroscience of multilingualism ,Communication ,business.industry ,Translation (biology) ,Recognition, Psychology ,Awareness ,Translating ,Second-language acquisition ,Paired-Associate Learning ,Neuropsychology and Physiological Psychology ,Practice, Psychological ,Mental Recall ,Female ,Psychology ,business ,Priming (psychology) ,Cognitive psychology - Abstract
Non-cognate masked translation priming lexical decision studies with unbalanced bilinguals suggest that masked translation priming effects are asymmetric as a function of the translation direction (significant effects only in the dominant [L1] to nondominant [L2] language translation direction). However, in contrast to the predictions of most current accounts of masked translation priming effects, bidirectional effects have recently been reported with a group of low proficient bilinguals Duyck & Warlop 2009 (Experimental Psychology 56:173–179). In a series of masked translation priming lexical decision experiments we examined whether the same pattern of effects would emerge with late and low proficient Greek (L1)–Spanish (L2) bilinguals. Contrary to the results obtained by Duyck and Warlop, and in line with the results found in most studies in the masked priming literature, significant translation priming effects emerged only when the bilinguals performed the task with L1 primes and L2 targets. The existence of the masked translation priming asymmetry with low proficient bilinguals suggests that cross-linguistic automatic lexico-semantic links may be established very early in the process of L2 acquisition. These findings could help to define models of bilingualism that consider L2 proficiency level to be a determining factor.
- Published
- 2011
18. Learning of a T-maze by rat pups when contact with the mother is either permitted or denied
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Fotini Stylianopoulou, Maria Dimitropoulou, Anastasia Diamantopoulou, Antonios Stamatakis, and Theofanis I Panagiotaropoulos
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Male ,Photomicrography ,Offspring ,Cognitive Neuroscience ,Experimental and Cognitive Psychology ,Stimulation ,Striatum ,Positive Reinforcer ,Stimulus (physiology) ,Hippocampus ,Procedural memory ,Behavioral Neuroscience ,Reward ,Memory ,Animals ,Rats, Wistar ,Maternal Behavior ,Maze Learning ,Analysis of Variance ,Maternal Deprivation ,T-maze ,Immunohistochemistry ,Corpus Striatum ,Frontal Lobe ,Rats ,Animals, Newborn ,Orbitofrontal cortex ,Psychology ,Proto-Oncogene Proteins c-fos ,Neuroscience ,psychological phenomena and processes - Abstract
Mother–pup interactions constitute an important component of environmental stimulation of the offspring during the neonatal period. Employing maternal contact as either a positive reinforcer or, its denial, as a frustrative, non-rewarding stimulus, we developed a novel experimental paradigm involving learning by rat neonates of a T-maze. When trained under the reward of maternal contact during postnatal days 10–13 Wistar rat pups learned the choice leading to the mother in a T-maze. When tested 2 h later, in the absence of the mother, pups showed a clear preference for the arm of the T-maze leading to the position of the mother during training. Furthermore, pups receiving the expected reward of maternal contact had higher numbers of c-Fos immunopositive cells in the dorsal striatum compared to either naive or pups denied the expected reward. The above behavioral and cellular results indicate that pups receiving the expected reward developed a procedural-like memory. When trained under frustrative non-reward pups learned to make the correct choice in the T-maze, albeit less efficiently than pups receiving the expected reward. Following this training condition c-Fos immunohistochemistry revealed increased activation of the CA1 area of the hippocampus and the orbitofrontal cortex. Expression of the information learned by the pups denied the expected reward was contingent upon the presence of the mother in the experimental setup in exactly the same configuration as during the training.
- Published
- 2009
19. k-th Best Device Selection for Scheduling in Wireless Powered Communication Networks
- Author
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Maria Dimitropoulou, Constantinos Psomas, and Ioannis Krikidis
- Subjects
9. Industry and infrastructure ,k-th best selection, order statistics, wireless power transfer, extreme value theory ,7. Clean energy - Abstract
This paper studies the performance of a wireless powered communication network consisting of a finite number of batteryless devices that harvest radio frequency energy. We consider novel selection/scheduling schemes, where the k-th best device is selected for information transmission. The proposed schemes correspond to different complexity and are based on: a) the end-to end (e2e) signal-to-noise ratio (SNR), b) the energy harvested at the devices, and c) the conventional channel-based max-min selection policy. By considering a non-linear energy harvesting (EH) model, we derive analytical expressions for the outage probability of each selection scheme by using high order statistics. We also consider an asymptotic scenario, where the number of devices increases and analyze the behavior of the system by applying extreme value theory. Due to the saturation effects of the non linear EH model, the performance of all the proposed schemes converges to an error floor. Our results show that the scheme based on the e2e SNR achieves the best performance and the one based on the EH the worst. The derived analytical framework provides useful insights on the design of such networks.
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