Refine
Year of publication
Document Type
- Article (10)
- Postprint (5)
- Doctoral Thesis (2)
- Master's Thesis (1)
- Other (1)
- Review (1)
Keywords
- memory (20) (remove)
Institute
- Department Psychologie (7)
- Institut für Biochemie und Biologie (3)
- Hasso-Plattner-Institut für Digital Engineering GmbH (2)
- Humanwissenschaftliche Fakultät (2)
- Institut für Anglistik und Amerikanistik (2)
- Strukturbereich Kognitionswissenschaften (2)
- Fakultät für Gesundheitswissenschaften (1)
- Institut für Geowissenschaften (1)
- Institut für Künste und Medien (1)
- Institut für Slavistik (1)
Many environmental conditions fluctuate and organisms need to respond effectively. This is especially true for temperature cues that can change in minutes to seasons and often follow a diurnal rhythm. Plants cannot migrate and most cannot regulate their temperature. Therefore, a broad array of responses have evolved to deal with temperature cues from freezing to heat stress. A particular response to mildly elevated temperatures is called thermomorphogenesis, a suite of morphological adaptations that includes thermonasty, formation of thin leaves and elongation growth of petioles and hypocotyl. Thermomorphogenesis allows for optimal performance in suboptimal temperature conditions by enhancing the cooling capacity. When temperatures rise further, heat stress tolerance mechanisms can be induced that enable the plant to survive the stressful temperature, which typically comprises cellular protection mechanisms and memory thereof. Induction of thermomorphogenesis, heat stress tolerance and stress memory depend on gene expression regulation, governed by diverse epigenetic processes. In this Tansley review we update on the current knowledge of epigenetic regulation of heat stress tolerance and elevated temperature signalling and response, with a focus on thermomorphogenesis regulation and heat stress memory. In particular we highlight the emerging role of H3K4 methylation marks in diverse temperature signalling pathways.
Viper
(2021)
Key-value stores (KVSs) have found wide application in modern software systems. For persistence, their data resides in slow secondary storage, which requires KVSs to employ various techniques to increase their read and write performance from and to the underlying medium. Emerging persistent memory (PMem) technologies offer data persistence at close-to-DRAM speed, making them a promising alternative to classical disk-based storage. However, simply drop-in replacing existing storage with PMem does not yield good results, as block-based access behaves differently in PMem than on disk and ignores PMem's byte addressability, layout, and unique performance characteristics. In this paper, we propose three PMem-specific access patterns and implement them in a hybrid PMem-DRAM KVS called Viper. We employ a DRAM-based hash index and a PMem-aware storage layout to utilize the random-write speed of DRAM and efficient sequential-write performance PMem. Our evaluation shows that Viper significantly outperforms existing KVSs for core KVS operations while providing full data persistence. Moreover, Viper outperforms existing PMem-only, hybrid, and disk-based KVSs by 4-18x for write workloads, while matching or surpassing their get performance.
Viper
(2021)
Key-value stores (KVSs) have found wide application in modern software systems. For persistence, their data resides in slow secondary storage, which requires KVSs to employ various techniques to increase their read and write performance from and to the underlying medium. Emerging persistent memory (PMem) technologies offer data persistence at close-to-DRAM speed, making them a promising alternative to classical disk-based storage. However, simply drop-in replacing existing storage with PMem does not yield good results, as block-based access behaves differently in PMem than on disk and ignores PMem's byte addressability, layout, and unique performance characteristics. In this paper, we propose three PMem-specific access patterns and implement them in a hybrid PMem-DRAM KVS called Viper. We employ a DRAM-based hash index and a PMem-aware storage layout to utilize the random-write speed of DRAM and efficient sequential-write performance PMem. Our evaluation shows that Viper significantly outperforms existing KVSs for core KVS operations while providing full data persistence. Moreover, Viper outperforms existing PMem-only, hybrid, and disk-based KVSs by 4-18x for write workloads, while matching or surpassing their get performance.
Emotional memories are better remembered than neutral ones, but the mechanisms leading to this memory bias are not well under-stood in humans yet. Based on animal research, it is suggested that the memory-enhancing effect of emotion is based on central nor-adrenergic release, which is triggered by afferent vagal nerve activation. To test the causal link between vagus nerve activation and emotional memory in humans, we applied continuous noninvasive transcutaneous auricular vagus nerve stimulation (taVNS) during exposure to emotional arousing and neutral scenes and tested subsequent, long-term recognition memory after 1 week. We found that taVNS, compared with sham, increased recollection-based memory performance for emotional, but not neutral, material. These findings were complemented by larger recollection-related brain potentials (parietal ERP Old/New effect) during retrieval of emotional scenes encoded under taVNS, compared with sham. Furthermore, brain potentials recorded during encoding also revealed that taVNS facilitated early attentional discrimination between emotional and neutral scenes. Extending animal research, our behavioral and neu-ral findings confirm a modulatory influence of the vagus nerve in emotional memory formation in humans.
Debates on the relevance of repatriation of indigenous human remains are water under the bridge today. Yet, a genuine will for dialogue to work through colonial violence is found lacking in the European public sphere. Looking at local remembrance of the Majimaji War (1905-07) in the south of Tanzania and a German-Tanzanian theatre production, this article demonstrates how the spectre of colonial headhunting stands at the heart of claims for repatriation and acknowledgement of this anti-colonial movement. The missing head of Ngoni leader Songea Mbano haunts the future of German-Tanzanian relations in culture and heritage. By staging the act of post-mortem dismemberment and foregrounding the perspective of descendants, the theatre production Maji Maji Flava offers an honest proposal for dealing with stories of sheer colonial violence in transnational memory.
Remembering the dismembered
(2020)
This thesis – written in co-authorship with Tanzanian activist Mnyaka Sururu Mboro – examines different cases of repatriation of ancestral remains to African countries and communities through the prism of postcolonial memory studies. It follows the theft and displacement of prominent ancestors from East and Southern Africa (Sarah Baartman, Dawid Stuurman, Mtwa Mkwawa, Songea Mbano, King Hintsa and the victims of the Ovaherero and Nama genocides) and argues that efforts made for the repatriation of their remains have contributed to a transnational remembrance of colonial violence.
Drawing from cultural studies theories such as "multidirectional memory", "rehumanisation" and "necropolitics", the thesis argues for a new conceptualisation or "re-membrance" in repatriation, through processes of reunion, empowerment, story-telling and belonging. Besides, the afterlives of the dead ancestors, who stand at the centre of political debates on justice and reparations, remind of their past struggles against colonial oppression. They are therefore "memento vita", fostering counter-discourses that recognize them
as people and stories.
This manuscript is accompanied by a “(web)site of memory” where some of the research findings are made available to a wider audience. This blog also hosts important sound material which appears in the thesis as interventions by external contributors. Through QR codes, both the written and the digital version are linked with each other to problematize the idea of a written monograph and bring a polyphonic perspective to those diverse, yet connected, histories.
It has frequently been observed that single emotional events are not only more efficiently processed, but also better remembered, and form longer-lasting memory traces than neutral material. However, when emotional information is perceived as a part of a complex event, such as in the context of or in relation to other events and/or source details, the modulatory effects of emotion are less clear. The present work aims to investigate how emotional, contextual source information modulates the initial encoding and subsequent long-term retrieval of associated neutral material (item memory) and contextual source details (contextual source memory). To do so, a two-task experiment was used, consisting of an incidental encoding task in which neutral objects were displayed over different contextual background scenes which varied in emotional content (unpleasant, pleasant, and neutral), and a delayed retrieval task (1 week), in which previously-encoded objects and new ones were presented. In a series of studies, behavioral indices (Studies 2, 3, and 5), event-related potentials (ERPs; Studies 1-4), and functional magnetic resonance imaging (Study 5) were used to investigate whether emotional contexts can rapidly tune the visual processing of associated neutral information (Study 1) and modulate long-term item memory (Study 2), how different recognition memory processes (familiarity vs. recollection) contribute to these emotion effects on item and contextual source memory (Study 3), whether the emotional effects of item memory can also be observed during spontaneous retrieval (Sstudy 4), and which brain regions underpin the modulatory effects of emotional contexts on item and contextual source memory (Study 5). In Study 1, it was observed that emotional contexts by means of emotional associative learning, can rapidly alter the processing of associated neutral information. Neutral items associated with emotional contexts (i.e. emotional associates) compared to neutral ones, showed enhanced perceptual and more elaborate processing after one single pairing, as indexed by larger amplitudes in the P100 and LPP components, respectively. Study 2 showed that emotional contexts produce longer-lasting memory effects, as evidenced by better item memory performance and larger ERP Old/New differences for emotional associates. In Study 3, a mnemonic differentiation was observed between item and contextual source memory which was modulated by emotion. Item memory was driven by familiarity, independently of emotional contexts during encoding, whereas contextual source memory was driven by recollection, and better for emotional material. As in Study 2, enhancing effects of emotional contexts for item memory were observed in ERPs associated with recollection processes. Likewise, for contextual source memory, a pronounced recollection-related ERP enhancement was observed for exclusively emotional contexts. Study 4 showed that the long-term recollection enhancement of emotional contexts on item memory can be observed even when retrieval is not explicitly attempted, as measured with ERPs, suggesting that the emotion enhancing effects on memory are not related to the task embedded during recognition, but to the motivational relevance of the triggering event. In Study 5, it was observed that enhancing effects of emotional contexts on item and contextual source memory involve stronger engagement of the brain's regions which are associated with memory recollection, including areas of the medial temporal lobe, posterior parietal cortex, and prefrontal cortex.
Taken together, these findings suggest that emotional contexts rapidly modulate the initial processing of associated neutral information and the subsequent, long-term item and contextual source memories. The enhanced memory effects of emotional contexts are strongly supported by recollection rather than familiarity processes, and are shown to be triggered when retrieval is both explicitly and spontaneously attempted. These results provide new insights into the modulatory role of emotional information on the visual processing and the long-term recognition memory of complex events. The present findings are integrated into the current theoretical models and future ventures are discussed.
The border shifts and population exchanges between Central and East European states agreed at the 1945 Potsdam Conference continue to reverberate in the culture and politics of those countries. Focusing on Poland, this article proposes the term “border trouble” to interpret the politicized split in memory that has run through Polish culture since the end of the Second World War. Border trouble is a form of cultural trauma that transcends binaries of perpetrator/victim and oppressor/oppressed; it is also a tool for analyzing the ways in which spatial imagination, memory, and identity interact in visual and literary narratives. A close analysis of four recent feature films demonstrates the emergence of a visual grammar of cosmopolitan memory and identity in relation to borderland spaces. Wojciech Smarzowski’s Róża (“Rose,” 2011) and Agnieszka Holland’s Pokot (“Spoor,” 2017) are both set in territories that were transferred from Germany to Poland in 1945. Wołyń (“Volhynia,” released internationally as “Hatred,” 2016) and W ciemności (“In Darkness,” 2011), also directed by Smarzowski and Holland respectively, are set in regions that were under Polish administration before the war but were transferred to Soviet Ukraine in 1945. All four productions break new ground in the memorialization of the post-war legacy in Poland. They deconstruct hitherto dominant discourses of simultaneity and ethnic homogeneity, engaging in Poland’s wars of symbols as a third voice: anti-nationalist, but also refusing to essentialize cosmopolitan identity. They show the evolution of border trouble in response to contemporary political and cultural developments.
Recollecting bones
(2018)
This article critically engages with the different politics of memory involved in debates over the restitution of Indigenous Australian ancestral remains stolen by colonial actors in the nineteenth and early twentieth centuries and brought to Berlin in the name of science. The debates crystallise how deeply divided German scientific discourses still are over the question of whether the historical and moral obligations of colonial injustice should be accepted or whether researchers should continue to profess scientific disinterest'. The debates also reveal an almost unanimous disavowal of Indigenous Australian knowledges and mnemonic conceptions across all camps. The bitter ironies of this disavowal become evident when Indigenous Australian quests for the remains of their ancestral dead lost in the limbo of German scientific collections are juxtaposed with white Australian (fictional) quests for the remains of Ludwig Leichhardt, lost in the Australian interior.
In a self-paced reading study on German sluicing, Paape (Paape, 2016) found that reading times were shorter at the ellipsis site when the antecedent was a temporarily ambiguous garden-path structure. As a post-hoc explanation of this finding, Paape assumed that the antecedent’s memory representation was reactivated during syntactic reanalysis, making it easier to retrieve. In two eye tracking experiments, we subjected the reactivation hypothesis to further empirical scrutiny. Experiment 1, carried out in French, showed no evidence in favor in the reactivation hypothesis. Instead, results for one out of the three types of garden-path sentences that were tested suggest that subjects sometimes failed to resolve the temporary ambiguity in the antecedent clause, and subsequently failed to resolve the ellipsis. The results of Experiment 2, a conceptual replication of Paape’s (Paape, 2016) original study carried out in German, are compatible with the reactivation hypothesis, but leave open the possibility that the observed speedup for ambiguous antecedents may be due to occasional retrievals of an incorrect structure.