Auditory stream segregation in cochlear implant listeners:measures based on temporal discrimination and interleaved melody recognition

The evidence that cochlear implant listeners routinely experience stream segregation is limited and equivocal. Streaming in these listeners was explored using tone sequences matched to the center frequencies of the implant’s 22 electrodes. Experiment 1 measured temporal discrimination for short (ABA triplet) and longer (12 AB cycles) sequences (tone/silence durations = 60/40 ms). Tone A stimulated electrode 11; tone B stimulated one of 14 electrodes. On each trial, one sequence remained isochronous, and tone B was delayed in the other; listeners had to identify the anisochronous interval. The delay was introduced in the second half of the longer sequences. Prior build-up of streaming should cause thresholds to rise more steeply with increasing electrode separation, but no interaction with sequence length was found. Experiment 2 required listeners to identify which of two target sequences was present when interleaved with distractors (tone/silence durations = 120/80 ms). Accuracy was high for isolated targets, but most listeners performed near chance when loudness-matched distractors were added, even when remote from the target. Only a substantial reduction in distractor level improved performance, and this effect did not interact with target-distractor separation. These results indicate that implantees often do not achieve stream segregation, even in relatively unchallenging tasks.

Effects of inducer continuity on auditory stream segregation:comparison of physical and perceived continuity in different contexts

The factors influencing the stream segregation of discrete tones and the perceived continuity of discrete tones as continuing through an interrupting masker are well understood as separate phenomena. Two experiments tested whether perceived continuity can influence the build-up of stream segregation by manipulating the perception of continuity during an induction sequence and measuring streaming in a subsequent test sequence comprising three triplets of low and high frequency tones (LHL-…). For experiment 1, a 1.2-s standard induction sequence comprising six 100-ms L-tones strongly promoted segregation, whereas a single extended L-inducer (1.1 s plus 100-ms silence) did not. Segregation was similar to that following the single extended inducer when perceived continuity was evoked by inserting noise bursts between the individual tones. Reported segregation increased when the noise level was reduced such that perceived continuity no longer occurred. Experiment 2 presented a 1.3-s continuous inducer created by bridging the 100-ms silence between an extended L-inducer and the first test-sequence tone. This configuration strongly promoted segregation. Segregation was also increased by filling the silence after the extended inducer with noise, such that it was perceived like a bridging inducer. Like physical continuity, perceived continuity can promote or reduce test-sequence streaming, depending on stimulus context.

Build-up of the tendency to segregate auditory streams:resetting effects of single deviant tones

The tendency to hear a sequence of alternating low (L) and high (H) frequency tones as two streams can be increased by a preceding induction sequence, even one composed only of same-frequency tones. Four experiments used such an induction sequence (10 identical L tones) to promote segregation in a shorter test sequence comprising L and H tones. Previous studies have shown that the build-up of stream segregation is usually reduced greatly when a sudden change in acoustic properties distinguishes all of the induction tones from their test-sequence counterparts. Experiment 1 showed that a single deviant tone, created by altering the final inducer (in frequency, level, duration, or replacement with silence) reduced reported segregation, often substantially. Experiment 2 partially replicated this finding, using changes in temporal discrimination as a measure of streaming. Experiments 3 and 4 varied the size of a frequency change applied to the deviant tone; the extent of resetting varied with size only gradually. The results suggest that resetting begins to occur once the change is large enough to be noticeable. Since the prior inducers always remained unaltered in the deviant-tone conditions, it is proposed that a single change actively resets the build-up evoked by the induction sequence.

Build-up and resetting of auditory stream segregation in quiet and in complex-tone backgrounds

Thirteen experiments investigated the dynamics of stream segregation. Experiments 1-6b used a similar method, where a same-frequency induction sequence (usually 10 repetitions of an identical pure tone) promoted segregation in a subsequent, briefer test sequence (of alternating low- and high-frequency tones). Experiments 1-2 measured streaming using a direct report of perception and a temporal-discrimination task, respectively. Creating a single deviant by altering the final inducer (e.g. in level or replacement with silence) reduced segregation, often substantially. As the prior inducers remained unaltered, it is proposed that the single change actively reset build-up. The extent of resetting varied gradually with the size of a frequency change, once noticeable (experiments 3a-3b). By manipulating the serial position of a change, experiments 4a-4b demonstrated that resetting only occurred when the final inducer was replaced with silence, as build-up is very rapid during a same-frequency induction sequence. Therefore, the observed resetting cannot be explained by fewer inducers being presented. Experiment 5 showed that resetting caused by a single deviant did not increase when prior inducers were made unpredictable in frequency (four-semitone range). Experiments 6a-6b demonstrated that actual and perceived continuity have a similar effect on subsequent streaming judgements promoting either integration or segregation, depending on listening context. Experiment 7 found that same-frequency inducers were considerably more effective at promoting segregation than an alternating-frequency inducer, and that a trend for deviant-tone resetting was only apparent for the same-frequency case. Using temporal-order judgments, experiments 8-9 demonstrated the stream segregation of pure-tone-like percepts, evoked by sudden changes in amplitude or interaural time difference for individual components of a complex tone, Active resetting was observed when a deviant was inserted into a sequence of these percepts (Experiment 10). Overall, these experiments offer new insight into the segregation-promotIng effect of induction sequences, and the factors which can reset this effect.

Build-up of auditory stream segregation induced by tone sequences of constant or alternating frequency and the resetting effects of single deviants

A sequence of constant-frequency tones can promote streaming in a subsequent sequence of alternating-frequency tones, but why this effect occurs is not fully understood and its time course has not been investigated. Experiment 1 used a 2.0-s-long constant-frequency inducer (10 repetitions of a low-frequency pure tone) to promote segregation in a subsequent, 1.2-s test sequence of alternating low- and high-frequency tones. Replacing the final inducer tone with silence substantially reduced reported test-sequence segregation. This reduction did not occur when either the 4th or 7th inducer was replaced with silence. This suggests that a change at the induction/test-sequence boundary actively resets build-up, rather than less segregation occurring simply because fewer inducer tones were presented. Furthermore, Experiment 2 found that a constant-frequency inducer produced its maximum segregation-promoting effect after only three tones—this contrasts with the more gradual build-up typically observed for alternating-frequency sequences. Experiment 3 required listeners to judge continuously the grouping of 20-s test sequences. Constant-frequency inducers were considerably more effective at promoting segregation than alternating ones; this difference persisted for ~10 s. In addition, resetting arising from a single deviant (longer tone) was associated only with constant-frequency inducers. Overall, the results suggest that constant-frequency inducers promote segregation by capturing one subset of test-sequence tones into an ongoing, preestablished stream, and that a deviant tone may reduce segregation by disrupting this capture. These findings offer new insight into the dynamics of stream segregation, and have implications for the neural basis of streaming and the role of attention in stream formation. (PsycINFO Database Record (c) 2013 APA, all rights reserved)

The 'silent dilemma' of transitional justice:silencing and coming to terms with the past in Serbia

This article explores the intersections of silence and transitional justice in Serbia, where, it is often suggested, the general public is silent and indifferent about human rights abuses that took place during the former Yugoslav conflicts. It considers both the 'silent' public and the ways in which transitional justice may be complicit in silencing it. Based on scholarship that suggests silences are not absences but rather sites of silent knowledge or a result of silencing, the article explores some of the dynamics hidden within the public's silence: shared knowledge, secret practices and inability to discuss violence. It also considers the ways in which audiences subvert and resist organized transitional justice initiatives or are caught up in a 'silent dilemma' in which they are unable to speak about the past under the discursive conditions created by transitional justice practitioners.

Build-up of auditory stream segregation induced by tone sequences of constant or alternating frequency and the resetting effects of single deviants

A sequence of constant-frequency tones can promote streaming in a subsequent sequence of alternating-frequency tones, but why this effect occurs is not fully understood and its time course has not been investigated. Experiment 1 used a 2.0-s-long constant-frequency inducer (10 repetitions of a low-frequency pure tone) to promote segregation in a subsequent, 1.2-s test sequence of alternating low- and high-frequency tones. Replacing the final inducer tone with silence substantially reduced reported test-sequence segregation. This reduction did not occur when either the 4th or 7th inducer was replaced with silence. This suggests that a change at the induction/test-sequence boundary actively resets build-up, rather than less segregation occurring simply because fewer inducer tones were presented. Furthermore, Experiment 2 found that a constant-frequency inducer produced its maximum segregation-promoting effect after only three tones—this contrasts with the more gradual build-up typically observed for alternating-frequency sequences. Experiment 3 required listeners to judge continuously the grouping of 20-s test sequences. Constant-frequency inducers were considerably more effective at promoting segregation than alternating ones; this difference persisted for ~10 s. In addition, resetting arising from a single deviant (longer tone) was associated only with constant-frequency inducers. Overall, the results suggest that constant-frequency inducers promote segregation by capturing one subset of test-sequence tones into an ongoing, preestablished stream, and that a deviant tone may reduce segregation by disrupting this capture. These findings offer new insight into the dynamics of stream segregation, and have implications for the neural basis of streaming and the role of attention in stream formation. (PsycINFO Database Record (c) 2013 APA, all rights reserved)

Build-up of auditory stream segregation induced by tone sequences of constant or alternating frequency and the resetting effects of single deviants

Three experiments investigated the dynamics of auditory stream segregation. Experiment 1 used a 2.0-s constant-frequency inducer (10 repetitions of a low-frequency pure tone) to promote segregation in a subsequent, 1.2-s test sequence of alternating low- and high-frequency tones. Replacing the final inducer tone with silence reduced reported test-sequence segregation substantially. This reduction did not occur when either the 4th or 7th inducer was replaced with silence. This suggests that a change at the induction/test-sequence boundary actively resets buildup, rather than less segregation occurring simply because fewer inducer tones were presented. Furthermore, Experiment 2 found that a constant-frequency inducer produced its maximum segregation-promoting effect after only 3 tone cycles - this contrasts with the more gradual build-up typically observed for alternating sequences. Experiment 3 required listeners to judge continuously the grouping of 20-s test sequences. Constant-frequency inducers were considerably more effective at promoting segregation than alternating ones; this difference persisted for ∼10 s. In addition, resetting arising from a single deviant (longer tone) was associated only with constant-frequency inducers. Overall, the results suggest that constant-frequency inducers promote segregation by capturing one subset of test-sequence tones into an on-going, pre-established stream and that a deviant tone may reduce segregation by disrupting this capture. © 2013 Acoustical Society of America.

Performance analysis of IEEE 802.11 cognitive radio ad hoc networks

IEEE 802.11 standard is the dominant technology for wireless local area networks (WLANs). In the last two decades, the Distributed coordination function (DCF) of IEEE 802.11 standard has become the one of the most important media access control (MAC) protocols for mobile ad hoc networks (MANETs). The DCF protocol can also be combined with cognitive radio, thus the IEEE 802.11 cognitive radio ad hoc networks (CRAHNs) come into being. There were several literatures which focus on the modeling of IEEE 802.11 CRAHNs, however, there is still no thorough and scalable analytical models for IEEE 802.11 CRAHNs whose cognitive node (i.e., secondary user, SU) has spectrum sensing and possible channel silence process before the MAC contention process. This paper develops a unified analytical model for IEEE 802.11 CRAHNs for comprehensive MAC layer queuing analysis. In the proposed model, the SUs are modeled by a hyper generalized 2D Markov chain model with an M/G/1/K model while the primary users (PUs) are modeled by a generalized 2D Markov chain and an M/G/1/K model. The performance evaluation results show that the quality-of-service (QoS) of both the PUs and SUs can be statistically guaranteed with the suitable settings of duration of channel sensing and silence phase in the case of under loading.

Violence against women in Ethiopia

Investigating the experience of violence against women and exploring women's coping strategies is a crucial component of re-tailoring the provision of services for victims/survivors. This article explores violence against women in the context of culture, theory of fear of violence and literature on spaces perceived to be 'safe' or 'dangerous' by women victims/survivors of violence in Ethiopia. To collect the relevant data, we conducted 14 semi-structured interviews with Ethiopian women who are victims/survivors of violence and three interviews with gender experts in Ethiopia. Our group of women suffer in 'silence' and confide only in friends and relatives. They did not resort to institutional support due to lack of awareness and general societal disapproval of such measures. This contrasts with claims by experts that the needs of these women are addressed using an institutional approach. Culture, migration status and lack of negotiating power in places of work are key factors when considering violence. The majority of the respondents in this study occupy both public and private spaces such as bars and homes and have experienced violence in those spaces. The social relations and subsequent offences they endured do not make spaces such as these safe. Education of both sexes, creation of awareness, sustainable resource allocation to support victims/survivors, ratification of the Maputo protocol and effective law enforcement institutions are some of the practical strategies we propose to mitigate the incidence of violence in Ethiopia. © 2010 Taylor & Francis.

A nettó jelenérték maximalizálása erőforrás-korlátos projektekben - egy új harmóniakereső metaheurisztika (A harmony search metaheuristic for the resourceconstrained project scheduling problem with discounted cash flows)

Ebben a tanulmányban a szerző egy új harmóniakereső metaheurisztikát mutat be, amely a minimális időtartamú erőforrás-korlátos ütemezések halmazán a projekt nettó jelenértékét maximalizálja. Az optimális ütemezés elméletileg két egész értékű (nulla-egy típusú) programozási feladat megoldását jelenti, ahol az első lépésben meghatározzuk a minimális időtartamú erőforrás-korlátos ütemezések időtartamát, majd a második lépésben az optimális időtartamot feltételként kezelve megoldjuk a nettó jelenérték maximalizálási problémát minimális időtartamú erőforrás-korlátos ütemezések halmazán. A probléma NP-hard jellege miatt az egzakt megoldás elfogadható idő alatt csak kisméretű projektek esetében képzelhető el. A bemutatandó metaheurisztika a Csébfalvi (2007) által a minimális időtartamú erőforrás-korlátos ütemezések időtartamának meghatározására és a tevékenységek ennek megfelelő ütemezésére kifejlesztett harmóniakereső metaheurisztika továbbfejlesztése, amely az erőforrás-felhasználási konfliktusokat elsőbbségi kapcsolatok beépítésével oldja fel. Az ajánlott metaheurisztika hatékonyságának és életképességének szemléltetésére számítási eredményeket adunk a jól ismert és népszerű PSPLIB tesztkönyvtár J30 részhalmazán futtatva. Az egzakt megoldás generálásához egy korszerű MILP-szoftvert (CPLEX) alkalmaztunk. _______________ This paper presents a harmony search metaheuristic for the resource-constrained project scheduling problem with discounted cash flows. In the proposed approach, a resource-constrained project is characterized by its „best” schedule, where best means a makespan minimal resource constrained schedule for which the net present value (NPV) measure is maximal. Theoretically the optimal schedule searching process is formulated as a twophase mixed integer linear programming (MILP) problem, which can be solved for small-scale projects in reasonable time. The applied metaheuristic is based on the "conflict repairing" version of the "Sounds of Silence" harmony search metaheuristic developed by Csébfalvi (2007) for the resource-constrained project scheduling problem (RCPSP). In order to illustrate the essence and viability of the proposed harmony search metaheuristic, we present computational results for a J30 subset from the well-known and popular PSPLIB. To generate the exact solutions a state-of-the-art MILP solver (CPLEX) was used.

Poetica de la brevedad en Borges

Although he did not write copious novels, endless essays, or long poems, Jorge Luis Borges is considered one of today's best modern writers. His works have never been more than ten pages long. The purpose of this dissertation is to demonstrate that the willing use of concise expression in Borges's writings is inscribed in a poetic worldview of great implications. This view is based on the synthesis of philosophical, literary, and cultural issues that Borges interprets, discusses, refutes, and re-elaborates with a new conjectural approach. ^ This dissertation is based on a methodological review of all his current scholarly work and on a thorough examination of the four volumes of his Complete Works, edited by Emece, in 2002. His pantheistic vision, the epiphanic moments, and his love/hate relationship with language, conform an aesthetic of resounding silence that enlightens the hidden aspects of his brief masterpieces. ^ Even though Borgesian studies flood the library he once imagined, they have been presented in an isolated manner. This dissertation establishes a link among the various aforementioned aspects as studied by Borges scholars, and demonstrates the powerful influence of Borges's illuminating and precise vision. ^ Paradoxically, the poetry of brevity in Borges's works is filled with allusions to the things that Borges silences, because, from a panoramic pantheism, his words almost reach an epiphanic enlightenment that flashes between preterit and future nothingness. ^ By replacing extension with intensity, and mastering the art of omission, Borges's laborious work reaches power and concentration that only the very greatest talents can achieve. His delicate verbal conciseness provides his readers with a virtually infinite freedom of imagination because it exposes them to the chaotic world of mythical probabilities, where an instant encompasses eternity. ^

Dulce Maria Loynaz' Jardin: Subversive tropological discourse

The purpose of this dissertation is to analyze how the tropes or figurative discourse in Loynaz’s novel, Jardín, becomes a means by which she involves the reader within a text that subverts socio-cultural conventions. Through textual analysis, it explains how the poet communicates her views of the world as a conflictive space where existence is the will to live, life being a human construction like a garden, and a woman’s decision –often frustrated by men– to seek self-realization.^ By tracing some critical studies focused on polarities allegedly present in Jardín, such as: poetry/prose, lyric poetry/novel, word/silence, life/death, character novel/space novel, civilization/barbarism, posmodernismo/vanguardismo, and femininity/feminism, this essay explores Loynaz’s esthetic and ideological codes to demonstrate how opposition can be seen in her novel as part of her arrangement of an artistic philosophy.^ This research refers to three main sources: the semiotician Umberto Eco’s notion of the text’s indeterminacy as an opera aperta, reception theory, and Mikhail Bakhtin’s concept of dialogism. By applying these theories to the analysis of this novel, I seek to show Loynaz’s literary modus (tropological language) and ideological dictum , which correlate oppositions and transform them as a point of departure to reconsider civilized life. The poet is presented as an esthetic force that compels the reader to question some false values, by creating an implicit but intelligent dialogue between him/her and a lyrical text. To describe such literary procedure, I coin in this study the term dialirismo (dialyricism). ^ My essay is centered on the tropes through which Loynaz creates her dialyrical text. By focusing on metaphor, symbol, synecdoche, and metonymy, I examine Jardín as a convergence of the following conceptual aspects: intertextuality, primitivism, and feminist discourse. I argue that Loynaz’s novel is a creative response to the literary tradition, as well as a proposal to understand writing –and reading– as an open, interactive process in search not only of artistic values but also of critical knowledge.^ This exploration shows how the novelist faces a so-called civilized world through the eyes of her fictional character, Bárbara, who confronts patriarchal discourse. It celebrates Loynaz’s poetic representation of this inquisitive woman, in her fenced garden, as a human being who can see, above and beyond an iron curtain, the possibility to overcome an aggressive male-centered civilization.^

The representation of motherhood in contemporary Catalan fiction

This dissertation analyzes four twenty-first-century Catalan novels which present the complex positions occupied by mothers in the last seven decades. Its conceptual framework posits motherhood as both a changing social construction and a political institution in a constant state of flux. In Inma Monsó´s Todo un carácter (2001), Eva Piquer´s Una victoria diferente (2002), Carme Riera´s La mitad del alma (2004), and Najat El Hachmi´s El último patriarca (2008) motherhood is explored as a metaphorical act, a gender-constructing experience, as well as the locus of expression with regard to gender and power relations. During the dictatorship of Francisco Franco (1939–1975), the majority of women were excluded from public spaces, and forced to stay home to care for their husbands and children. Furthermore, the state criminalized abortion, made contraception and divorce illegal, and promoted an ideal of femininity based on silence, sacrifice, and self-denial. The political changes of the late 1970s allowed women greater personal autonomy, and many women writers began to challenge stereotypical views of women’s social roles. Yet in the 70s and 80s, the narratives of Esther Tusquets, Ana María Moix, and Montserrat Roig represent the mother as a repressive figure whom the daughter must reject in order to liberate herself and regain her voice. It is not until the 90s when the novelists Mercedes Abad, Maruja Torres, Carme Riera, Imma Monsó, Eva Piquer, and María Barbal rehumanize the mother figure, recovering their matrilineal heritage. However, far from suggesting a unified trend in representations of motherhood in Catalan fiction, the diverse points of view of the novels under discussion here reveal that differences in attitudes among women authors about mother-daughter conflict are far from resolved. The theoretical background for this dissertation draws mainly on the work of Adrienne Rich, Nancy Chodorow, and Julia Kristeva. It includes psychoanalytic studies as well as sociologically based essays by Anna López Puig, Amparo Acereda, Jacqueline Cruz, Barbara Zecchi, Ángeles de la Concha, and Raquel Osborne, among others.

Speaking Up: A Phenomenological Study of Student Perceptions of Being Silenced in their Higher Education Classrooms

This phenomenological study explored students’ experiences of being silenced in their higher education classroom. Themes emerging from this study include the influence of past experiences, devaluation of students’ previous knowledge and learning, use of communication patterns to silence students, and internalization of conflict and oppression resulting from being silenced.