Further Evidence for the Binding and Retrieval of Control-States From the Flanker Task

In response-interference tasks, congruency effects are reduced in trials that follow an incongruent trial. This congruence sequence effect (CSE) has been taken to reflect top-down cognitive control processes that monitor for and intervene in case of conflict. In contrast, episodic-memory accounts explain CSEs with bottom-up retrieval of stimulus-response links. Reconciling these opposing views, an emerging perspective holds that memory stores instances of control – abstract control-states – creating a shortcut for effortful control processes. Support comes from a study that assessed CSEs in a prime-target task. Here, repeating an irrelevant context feature boosted CSEs, possibly by retrieving previously stored control-states. We present a conceptual replication using the Eriksen flanker task because previous research found that CSEs in the flanker task reflect different control mechanisms than CSEs in the prime-target task. We measured CSEs while controlling for stimulus–response memory effects and manipulated contextual information (vertical spatial location) independently from the stimulus information, which introduced the conflict (horizontal spatial location). Results replicate previous findings – CSEs increased for context-repetition compared to context-changes. This study shows that retrieval of control-states is not limited to a specific task or context feature and therefore generalizes the notion that abstract control parameters are stored into trial-specific event files.

Post-Translational Modifications Optimize the Ability of SARS-CoV-2 Spike for Effective Interaction with Host Cell Receptors

SARS-CoV2 spike glycoprotein is prime target for vaccines and for diagnostics and therapeutic antibodies against the virus. While anchored in the viral envelope, for effective virulance, the spike needs to maintain structural flexibility to recognize the host cell surface receptors and bind to them, a property that can heavily hinge upon the dynamics of the unresolved domains, most prominently the stalk. Construction of the complete, membrane-bound spike model and the description of its dynamics remain critical steps in understanding the inner working of this key element in viral infection. Using a hybrid approach, combining homology modeling, protein-protein docking and MD simulations, guided by biochemical and glycomics data, we have developed a full-length, membrane-bound, palmitoylated and fully-glycosylated spike structure in a native membrane. Multi-microsecond MD simulations of this model, the longest known trajectory of the full-spike, reveals conformational dynamics employed by the protein to explore the crowded surface of the host cell. In agreement with cryoEM, three flexiblele hinges in stalk allow for global conformational heterogeneity of spike in the fully-glycosyslated system mediated by glycan-glycan and glycan-lipid interactions. Dynamical range of spike is considerably reduced in its non-glycosylated form, confining the area explored by the spike on the host cell surface. Furthermore, palmitoylation of the membrane domain amplify the local curvature that may prime the fusion. We show that the identified hinge regions are highly conserved in SARS coronaviruses, highlighting their functional importance in enhancing viral infection, and thereby provide novel points for discovery of alternative therapeutics against the virus.SignificanceSARS-CoV2 Spike protein, which forms the basis for high pathogenicity and transmissibility of the virus, is also prime target for the development of both diagnostics and vaccines for the debilitating disease caused by the virus. We present a full model of spike methodically crafted and used to study its atomic-level dynamics by multiple-µs simulations. The results shed new light on the impact of posttranslational modifications in the pathogenicity of the virus. We show how glycan-glycan and glycan-lipid interactions broaden the protein’s dynamical range, and thereby, its effective interaction with the surface receptors on the host cell. Palmitoylation of spike membrane domain, on the other hand, results in a unique deformation pattern that might prime the membrane for fusion.

Distributed reflection denial of service attack: A critical review

As the world becomes increasingly connected and the number of users grows exponentially and “things” go online, the prospect of cyberspace becoming a significant target for cybercriminals is a reality. Any host or device that is exposed on the internet is a prime target for cyberattacks. A denial-of-service (DoS) attack is accountable for the majority of these cyberattacks. Although various solutions have been proposed by researchers to mitigate this issue, cybercriminals always adapt their attack approach to circumvent countermeasures. One of the modified DoS attacks is known as distributed reflection denial-of-service attack (DRDoS). This type of attack is considered to be a more severe variant of the DoS attack and can be conducted in transmission control protocol (TCP) and user datagram protocol (UDP). However, this attack is not effective in the TCP protocol due to the three-way handshake approach that prevents this type of attack from passing through the network layer to the upper layers in the network stack. On the other hand, UDP is a connectionless protocol, so most of these DRDoS attacks pass through UDP. This study aims to examine and identify the differences between TCP-based and UDP-based DRDoS attacks.

Lack of affective priming indicates attitude-behaviour discrepancy for COVID-19 affiliated words

The ongoing novel coronavirus (COVID-19) pandemic has resulted in the enforcement of national public health safety measures including precautionary behaviours such as border closures, movement restrictions, total or partial lockdowns, social distancing, and face mask mandates in order to reduce the spread of this disease. The current study uses affective priming, an indirect behavioural measure of implicit attitude, to evaluate COVID-19 attitudes. Explicitly, participants rated their overall risk perception associated with contracting COVID-19 significantly lower compared to their perception of necessary precautions and overall adherence to public health measures. During baseline trials, participants explicitly rated COVID-19 affiliated words as unpleasant, similar to traditional unpleasant word stimuli. Despite rating the COVID-19 affiliated words as unpleasant, affective priming was not observed for congruent prime-target COVID-19 affiliated word pairs when compared to congruent prime-target pleasant and unpleasant words. Overall, these results provide quantitative evidence that COVID-19 affiliated words do not invoke the same implicit attitude response as traditional pleasant and unpleasant word stimuli, despite conscious explicit rating of the COVID-19 words as unpleasant. This reduction in unpleasant attitude towards COVID-19 related words may contribute towards decreased fear-related behaviours and increased incidences of risky-behaviour facilitating the movement of the virus.

Anticipating resistance to KRAS inhibition: a novel role for USP21 in macropinocytosis regulation

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers. Virtually all PDAC harbors an oncogenic mutation in the KRAS gene, making it the prime target for therapy. Most previous attempts to inhibit KRAS directly have been disappointing, but recent success in targeting some KRAS mutants presages a new era in PDAC therapy. Models of PDAC have predicted that identifying KRAS inhibitor resistance mechanisms will be critical. In this issue of Genes & Development, Hou and colleagues (pp. 1327–1332) identify one such mechanism in which the deubiquitinase USP21 up-regulates the nutrient-scavenging process of macropinocytosis, rescuing PDAC cells from Kras extinction.

EXPRESS: Controlled or automatic? Influence of congruency proportion and stimulus onset asynchrony on the brightness-valence and space-valence metaphoric congruency effects

Whether a cognitive process is operated automatically or in a controlled manner has been a long-standing question in cognitive psychology. However, this issue has not been investigated in the activation of metaphoric association. A primed word valence judgment task is often used to test the activation of metaphoric association, in which participants first see a prime (bright/dark square or fixation point moving up or down from the center of the screen) and then make a valence judgment to a target word. Metaphoric congruency effect occurs when participants make faster judgments to the target with valence being matched with the prime (good followed bright/top prime) than being mismatched with the prime (good followed dark/bottom prime). In the present two experiments, we manipulated prime-target stimulus onset asynchrony (SOA) and proportion of metaphorically congruent trials (congruency proportion) to tease apart the effects of automatic and controlled activation of brightness-valence and spatial-valence metaphoric associations on word valence judgments. Results showed an overall effect of congruency proportion on brightness-valence and spatial-valence metaphoric congruency effect, which was independent of prime-target SOA. The effect was enhanced or reversed when congruency proportion was higher or lower than 0.5, respectively, suggesting that the activation of metaphoric association could be modulated by strategic control. The implications of these findings on the Conceptual Metaphor Theory and semantic priming theories are discussed.

Lexical and syntactic influences on syntactic encoding in written language production by deaf speakers

It remains unclear whether deaf and hearing speakers differ in the processes and representations underlying written language production. Using the structural priming paradigm, this study investigated syntactic and lexical influences on syntactic encoding in writing by deaf speakers of Chinese in comparison with hearing controls. Experiment 1 showed that deaf speakers tended to re-use a prior syntactic structure in written sentence production (i.e., structural priming) to the same extent as hearing speakers did; in addition, such a tendency was enhanced when the target sentence repeated the verb from the prime sentence (i.e., lexical boost) in both deaf and hearing speakers to the same extent. These results suggest that deaf and hearing speakers are similarly affected by syntactic and lexical factors in syntactic encoding in writing. Experiment 2 revealed comparable boosts in structural priming between prime-target pairs with homographic homophone verbs and prime-target pairs with heterographic homophone verbs in hearing speakers, but a boost for prime-target pairs with homographic homophone verbs but not those with heterographic homophone verbs in deaf speakers. These results suggest that while syntactic encoding in writing is influenced by lemma associations developed for homophones as a result of phonological identity in hearing speakers, it is influenced by lemma associations developed for homographs as a result of orthographic identity in deaf speakers. In all, syntactic encoding in writing seems to employ the same syntactic and lexical representations in hearing and deaf speakers, though lexical representations are shaped more by orthography than phonology in deaf speakers.

Potato Tuber Shape Phenotyping Using RGB Imaging

Potato tuber shape is an important quality trait for breeding and variety development. Length to width (L/W) ratio is a commonly used method to score potato tubers for suitability for different markets and is relatively easy to measure, though labor intensive when done manually. L/W also does not adequately capture secondary growth and other tuber malformations that contribute to tuber shape. Tuber shape has a genetic component and is a prime target for early breeding selection. In the current study we developed an image analysis pipeline to extract tuber shape statistics from images taken using inexpensive, commercially available cameras. The image processing pipeline was used to evaluate greenhouse grown tubers from 32 unique crosses. Tubers from greenhouse grown plants were then grown in a field located in Vauxhall, AB, Canada, and evaluated for tuber shape. Randomly selected tuber images were also shown to industry agronomists and potato growers located in Southern Alberta and their shape scored for suitability for processing (French fry and chipping) markets. Based on measurements taken from greenhouse grown tubers we were able to classify whether mean tuber shape from field grown plants were within ideal shape parameters for processing markets with ~76–86% accuracy. Based on performance of progeny we identified parents which show higher breeding value for tuber shape.

Bilingual lexical representation

This paper has two aims: (1) to examine evidence for noncognate translation priming from cross-language masked priming studies of printed words. (2) to introduce an automatic procedure for creating masked speech priming experiments. For (1) we conducted two meta-analyses that aggregated evidence from masked translation priming studies in the L1 to L2 and L2 to L1 prime-target directions. These showed that there was evidence of significant priming for both directions, and that priming was larger for the L1-L2 direction. The analyses revealed considerable heterogeneity in outcomes, particularly for priming in the L1 to L2 direction. For (2) we outlined some of the practical difficulties that are involved in implementing a masked speech priming experiment and offered a largely automated solution (that we will make available).1 We then briefly considered whether the work with written primes and targets may translate to the spoken medium.