Children's acquisition of science terms: simple exposure is insufficient

The ability of school children (N = 233) to acquire new scientific vocabulary was examined. Children from two age groups (M = 4;8 and M = 6;5) were introduced to previously unknown words in an educational video. Word knowledge was assessed through accuracy and latency for production and comprehension over a nine month period. A draw and write task assessed acquisition of domain knowledge. Word learning was poorer than has previously been reported in the literature, and subject to influences of word type (domain-specificity) and word class. The results indicate that the acquisition of scientific terms is a complex process moderated by lexical, semantic and pragmatic factors

Graph embedding in SYNCHEM2, an expert system for organic synthesis discovery

AbstractGraph embedding (subgraph isomorphism) is an NP-complete problem of great theoretical and practical importance in the sciences, especially chemistry and computer science. This paper presents positive test results for techniques to speed embedding by modeling graphs with subroutines, precalculating edge tables, turning recursion into iteration, and using search-ordering heuristics.The expert system synchem2 searches for synthesis routes of organic molecules without the online guidance of a user, and this paper examines how embedding information helps to implement the central operations of synchem2: selection, application, and evaluation of chemical reactions. The paper also outlines the architecture of synchem2, analyzes the computational time complexity of embedding and related problems in graph isomorphism and canonical chemical naming, and suggests topics and techniques for further research

Exploring the neurobiology of reading through non-invasive brain stimulation: A review

Non-invasive brain stimulation (NIBS) has gained increasing popularity as a modulatory tool for drawing causal inferences and exploring task-specific network interactions. Yet, a comprehensive synthesis of reading-related NIBS studies is still missing. We fill this gap by synthesizing the results of 78 NIBS studies investigating the causal involvement of brain regions for reading processing, and then link these results to a neurobiological model of reading. The included studies provide evidence for a functional-anatomical double dissociation for phonology versus semantics during reading-related processes within left inferior frontal and parietal areas. Additionally, the posterior parietal cortex and the anterior temporal lobe are identified as critical regions for reading-related processes. Overall, the findings provide some evidence for a dual-stream neurobiological model of reading, in which a dorsal stream (left temporo-parietal and inferior frontal areas) processes unfamiliar words and pseudowords, and a ventral stream (left occipito-temporal and inferior frontal areas, with assistance from the angular gyrus and the anterior temporal lobe) processes known words. However, individual differences in reading abilities and strategies, as well as differences in stimulation parameters, may impact the neuromodulatory effects induced by NIBS. We emphasize the need to investigate task-specific network interactions in future studies by combining NIBS with neuroimaging

Repetition Priming and Anomia: An Investigation of Stimulus Dosage

In a recent review of anomia management, Maher & Raymer reported that 30% of aphasia intervention research from 1946 to 2001 focused on naming; however, despite this proliferation of case reports and small group studies, there is still no clear agreement on how best to manage these deficits (Maher & Raymer, 2004, p. 13). The inconsistency of acquisition, maintenance, and generalization effects observed across participants and types of treatment protocols is likely to stem from an inadequate knowledge base about how subject and treatment variables influence learning. One treatment variable that has received increasing attention over the past two or three years is treatment intensity. Principles of neurobiological learning across both animal and human research suggest that the intensity of treatment is a significant factor for learning. Additional research exploring experience-dependent neural plasticity involved in memory and learning indicates that a large number of trials per session are required to elicit behavioral and/or neural change. Despite a considerable amount of literature examining overall treatment intensity, data are not available regarding the frequency (i.e., stimulus dosage) of treatment at which individuals with aphasia will maximally benefit. A single-subject A-B design with replication across four individuals with aphasia and one healthy non-brain injured gender-matched control participant was used to assess the influence of repeated attempts at picture-naming, coupled with repeated exposure to hearing and reading target words, on the acquisition and maintenance of trained stimuli, and generalization to untrained stimuli. Individuals with chronic aphasia participated in a multi-week repetition priming protocol designed to investigate the influence of stimulus dosage on naming accuracy and latency. Results revealed positive repetition priming effects for trained items across both acquisition and maintenance phases; such positive effects were not observed for untrained stimuli or alternate exemplars. Stimulus dosage manipulations did not consistently influence naming performance for individuals with aphasia

A Cognitive Neuroscience Examination Of Rhythm And Reading And Their Translation To Neurological Conditions

The goal of the current research was to provide a novel and comprehensive examination of the connection between rhythm and reading through the combination of multiple experimental stimuli, and to translate the reading aloud research to neurological patients. Both speech and music perception/production involve sequences of rhythmic events that unfold over time, and the presence of rhythm in both processes has motivated researchers to consider whether musical and speech rhythm engage shared neural regions (Patel, 2008), and whether musical rhythm can influence speech processing (Cason & Schön, 2012). The experimental paradigm involved examining whether reading aloud is affected by the presentation of a rhythmic prime that was either congruent or incongruent with the syllabic stress of the target letter string. The experiments in Chapter 2 used targets that were words that placed the stress on either the first or second syllable (practice vs. police), as well as their corresponding pseudohomophones (praktis vs. poleese), which allowed us to compare lexical and sublexical reading, respectively. In Chapter 3, the experiments involved a paradigm in which target words have stress on the first syllable for nouns, and on the second syllable for verbs. Thus, the design used identical noun-verb word pairs (conflict vs. conflict), as well as their corresponding pseudohomophones (konflikt vs. konflikt). The results from the behavioural experiments demonstrated that naming reaction times were faster for words and pseudohomophones when the rhythmic prime was congruent with the syllabic stress, and slower when the rhythmic prime was incongruent, which suggests that a rhythmic prime matched to the syllabic stress of a letterstring aids reading processes. Functional magnetic resonance imaging (fMRI) was also used in Chapters 2 and 3 to test whether a network involving the putamen is involved in the effect of rhythm on reading aloud. The fMRI results revealed that a network involving the putamen is associated with the effect of congruency between rhythmic stress and syllabic stress on reading aloud, which is consistent with previous literature that has shown this region is involved in reading, rhythm processing, and predicting upcoming events. Chapter 4 was to provide a behavioural and neuroanatomical examination of reading processes in two patients. Case Study 1 examined the effect of rhythmic priming on reading aloud in a patient with Parkinson’s disease (PD), given that these patients exhibit abnormalities in the putamen, which has been associated with rhythm and reading processes. The patient demonstrated the same behavioural effect as normal participants, whereby individuals benefited from the rhythm prime being congruent with the syllabic stress of the target letter string, and the fMRI results revealed that despite disruptions in basal ganglia functioning following PD, there was still activation in the putamen for reading real words. Case Study 2 examined a patient with intractable left temporal lobe epilepsy (TLE) who was undergoing a temporal lobectomy that involved removing regions of the left temporal lobe that are often thought to be important in language processing. The fMRI results showed that all four reading tasks activated the right posterior occipitotemporal region in the ventral visual stream, confirming the right hemisphere dominance in this patient. Together, these findings have implications for developing neurobiological models of reading, translation to localization of function in neurological conditions such as PD and TLE, and may also reveal potential remedial applications for treating speech deficits in patient populations, such as Parkinson’s disease, stuttering, aphasia, and dyslexia

Neuromodulation as a cognitive enhancement strategy in healthy older adults: promises and pitfalls

Increases in life expectancy have been followed by an upsurge of age-associated cognitive decline. Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) have risen as promising approaches to prevent or delay such cognitive decline. However, consensus has not yet been reached about their efficacy in improving cognitive functioning in healthy older adults. Here we review the effects of TMS and tDCS on cognitive abilities in healthy older adults. Despite considerable variability in the targeted cognitive domains, design features and outcomes, the results generally show an enhancement or uniform benefit across studies. Most studies employed tDCS, suggesting that this technique is particularly well-suited for cognitive enhancement. Further work is required to determine the viability of these techniques as tools for long-term cognitive improvement. Importantly, the combination of TMS/tDCS with other cognitive enhancement strategies may be a promising strategy to alleviate the cognitive decline associated with the healthy aging process

Backscatter from the Data Plane --- Threats to Stability and Security in Information-Centric Networking

Information-centric networking proposals attract much attention in the ongoing search for a future communication paradigm of the Internet. Replacing the host-to-host connectivity by a data-oriented publish/subscribe service eases content distribution and authentication by concept, while eliminating threats from unwanted traffic at an end host as are common in today's Internet. However, current approaches to content routing heavily rely on data-driven protocol events and thereby introduce a strong coupling of the control to the data plane in the underlying routing infrastructure. In this paper, threats to the stability and security of the content distribution system are analyzed in theory and practical experiments. We derive relations between state resources and the performance of routers and demonstrate how this coupling can be misused in practice. We discuss new attack vectors present in its current state of development, as well as possibilities and limitations to mitigate them.Comment: 15 page