44 research outputs found
Stress assignment in reading Italian polysyllabic pseudowords.
In four naming experiments we investigated how Italian readers assign stress to pseudowords. We assessed whether participants assign stress following distributional information such as stress neighborhood (the proportion and number of existent words sharing orthographic ending and stress pattern) and whether such distributional information affects naming speed. Experiments 1 and 2 tested how readers assign stress to pseudowords. The results showed that participants assign stress on the basis of the pseudowords\u27 stress neighborhood, but only when this orthographic/phonological information is widely represented in the lexicon. Experiments 3 and 4 tested the naming speed of pseudowords with different stress patterns. Participants were faster in reading pseudowords with antepenultimate than with penultimate stress. The effect was not driven by distributional information, but it was related to the stage of articulation planning. Overall, the experiments showed that, under certain conditions, readers assign stress using orthographic/phonological distributional information. However, the distributional information does not speed up pseudoword naming, which is affected by stress computation at the level of the articulation planning of the stimulus. It is claimed that models of reading aloud and speech production should be merged at the level of phonological encoding, when segmental and metrical information are assembled and articulation is planned
The downsized hand in Personal Neglect
Objective: Personal neglect (PN) refers to a form of hemi-inattention toward the contralesional body space and it usually occurs following a right brain lesion. Recent studies suggest that PN indicates a disorder of body representation. Specifically, patients with PN show difficulties in identifying differences between left and right hands and have an altered visuospatial body map, which is associated with disrupted mental body representations. However, the metric representation of the body, and in particular the hands, has not been systematically addressed in patients showing this form of neglect.
Method: In the present study, we have investigated this representation by testing the perceived hands’ width of 11 hemiplegic patients with right hemisphere cerebral lesions (5 with PN) and 12 healthy controls on a judgment of passability task. Patients and controls were asked to imagine inserting their hand (left and right) through a series of vertical apertures of different sizes and to judge whether their hand could fit through. Due to the heterogeneity of the data, both parametric and non-parametric approaches were used. Furthermore, additional single-case analyses were conducted by using Crawford and Howell’s (1998) method.
Results: Study findings showed that patients with PN showed a significant underestimation of the left hand compared with their right hand. In contrast, whilst the right hand was equally distorted in both patients’ groups, the hemiplegic patients with no evidence of PN tended to perceive the affected hand as larger than their ipsilesional one.
Conclusions: In line with the literature, our findings confirm an underlying distorted body representation following right brain damage. However, for the first time, we report both a quantitative and qualitative difference in impact of hemiplegia and PN on body representation of the contralesional body space
Bilingual vocabulary size and lexical reading in Italian
In the present study we investigated how the vocabulary size of English-Italian bilinguals affects reading aloud in Italian (L2) modulating the reader\u27s sensitivity to lexical aspects of the language. We divided adult bilinguals in two groups according to their vocabulary size (Larger - LV, and smaller - SV), and compared their naming performance to that of native Italian (NI) readers. In Experiment 1 we investigated the lexicality and word frequency effects in reading aloud. Similarly to NI, both groups of bilinguals showed these effects. In Experiment 2 we investigated stress assignment - which is not predictable by rule - to Italian words. The SV group made more stress errors in reading words with a non-dominant stress pattern compared to the LV group. The results suggest that the size of the reader\u27s L2 lexicon affects the probability of correct reading aloud. Overall, the results indicate that proficient adult bilinguals show a similar sensibility to the statistical and distributional properties of the language as compared to Italian monolinguals
Dissociation in optokinetic stimulation sensitivity between omission and substitution reading errors in neglect dyslexia
Although omission and substitution errors in neglect dyslexia (ND) patients have always been considered as different manifestations of the same acquired reading disorder, recently, we proposed a new dual mechanism model. While omissions are related to the exploratory disorder which characterizes unilateral spatial neglect (USN), substitutions are due to a perceptual integration mechanism. A consequence of this hypothesis is that spe- cific training for omission-type ND patients would aim at restoring the oculo-motor scanning and should not improve reading in substitution-type ND. With this aim we administered an optokinetic stimulation (OKS) to two brain-damaged patients with both USN and ND, MA and EP, who showed ND mainly characterized by omissions and substitutions, respectively. MA also showed an impairment in oculo-motor behavior with a non-reading task, while EP did not. The two patients presented a dissociation with respect to their sensitivity to OKS, so that, as expected, MA was positively affected, while EP was not. Our results confirm a dissociation between the two mechanisms underlying omission and substitution reading errors in ND patients. Moreover, they suggest that such a dissociation could possibly be extended to the effectiveness of rehabilitative procedures, and that patients who mainly omit contralesional-sided letters would benefit from OKS
Sex Differences in Tobacco Abstinence: Effects on Executive Functioning
Aims. Several studies suggested that both sex and tobacco abstinence influence some cognitive processes such as memory and attention. However, very few studies have investigated whether males and females differ in executive functions in relation to tobacco abstinence. We investigated the effects of nicotine abstinence on executive functions in both males and females by using a virtual reality task (JEF).
Design. A 2x2x8 mixed ANOVA was performed, with the percentages of task’s scores as dependent variable. Condition (Smoking and Abstinence) and Construct [Planning, Prioritization, Selective Thinking, Creative Thinking, Adaptive Thinking, Action Based Prospective Memory (ABPM), Event Based Prospective Memory (EBPM), Time Based Prospective Memory (TBPM)] as within subjects independent variables and Sex as between subject independent variable. Setting. Department of Human Sciences, Lumsa University in Rome. Participants. Thirty adults smokers, all University students, participated in the study (half females) (M age = 24.53; range = 18 – 35).
Measurement. The Virtual Reality task (JEF), which assesses eight cognitive constructs.
Findings. The main effect of Construct was significant (p< .0001) as the interaction between Sex and Construct (p<.01); post-hoc analysis showed that females obtained the lowest score in creative thinking while males obtained the lowest score in action-based prospective memory. More importantly, the interaction between Condition and Sex was also significant (p<.05) and post-hoc analysis indicated that males’ performance improved in the abstinence condition, whereas females’ performance remained quite stable across them. In both groups, event-based and time-based prospective memories obtained the highest scores.
Conclusion. The results of this study partly confirmed previous findings about sex differences in cognitive processes and how tobacco abstinence may differently affect males and females. However, the use of a more sensitive ecological tool has permitted to capture isolated elements of executive functioning that reflect theories of fractionated executive processes and better clarify the effects of smoking and sex differences
Early Identification and Prevention of the Spread of Ebola - United States
In response to the 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa, CDC prepared for the potential introduction of Ebola into the United States. The immediate goals were to rapidly identify and isolate any cases of Ebola, prevent transmission, and promote timely treatment of affected patients. CDC\u27s technical expertise and the collaboration of multiple partners in state, local, and municipal public health departments; health care facilities; emergency medical services; and U.S. government agencies were essential to the domestic preparedness and response to the Ebola epidemic and relied on longstanding partnerships. CDC established a comprehensive response that included two new strategies: 1) active monitoring of travelers arriving from countries affected by Ebola and other persons at risk for Ebola and 2) a tiered system of hospital facility preparedness that enabled prioritization of training. CDC rapidly deployed a diagnostic assay for Ebola virus (EBOV) to public health laboratories. Guidance was developed to assist in evaluation of patients possibly infected with EBOV, for appropriate infection control, to support emergency responders, and for handling of infectious waste. CDC rapid response teams were formed to provide assistance within 24 hours to a health care facility managing a patient with Ebola. As a result of the collaborations to rapidly identify, isolate, and manage Ebola patients and the extensive preparations to prevent spread of EBOV, the United States is now better prepared to address the next global infectious disease threat.The activities summarized in this report would not have been possible without collaboration with many U.S. and international partners (http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/partners.html)
Safety, pharmacokinetics and antiviral activity of PGT121, a broadly neutralizing monoclonal antibody against HIV-1: a randomized, placebo-controlled, phase 1 clinical trial
Human immunodeficiency virus (HIV)-1-specific broadly neutralizing monoclonal antibodies are currently under development to treat and prevent HIV-1 infection. We performed a single-center, randomized, double-blind, dose-escalation, placebo-controlled trial of a single administration of the HIV-1 V3-glycan-specific antibody PGT121 at 3, 10 and 30 mg k
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Whole genome comparison of a large collection of mycobacteriophages reveals a continuum of phage genetic diversity
The bacteriophage population is large, dynamic, ancient, and genetically diverse. Limited genomic information shows that phage genomes are mosaic, and the genetic architecture of phage populations remains ill-defined. To understand the population structure of phages infecting a single host strain, we isolated, sequenced, and compared 627 phages of Mycobacterium smegmatis. Their genetic diversity is considerable, and there are 28 distinct genomic types (clusters) with related nucleotide sequences. However, amino acid sequence comparisons show pervasive genomic mosaicism, and quantification of inter-cluster and intra-cluster relatedness reveals a continuum of genetic diversity, albeit with uneven representation of different phages. Furthermore, rarefaction analysis shows that the mycobacteriophage population is not closed, and there is a constant influx of genes from other sources. Phage isolation and analysis was performed by a large consortium of academic institutions, illustrating the substantial benefits of a disseminated, structured program involving large numbers of freshman undergraduates in scientific discovery
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
Two different mechanisms for omission and substitution errors in neglect dyslexia
Neglect dyslexia is a reading disorder often associated with right-sided brain lesions. In reading single words, errors are mostly substitutions or omissions of letters that occupy the left-sided positions. Typically, these errors have been thought to depend on a single mechanism. Conversely, we propose that they are due to different mechanisms. In particular, a visuo-spatial mechanism is responsible for omissions and a perceptual integration process for substitution errors. We measured the performance of six patients with both neglect and neglect dyslexia, analyzing their reading errors as a function of letter spacing. According to our conjecture, letter spacing should increase omissions by moving part of the string further in the unattended space, while it should reduce substitutions by restoring the integration processes. Furthermore, we predict that letter spacing should be more effective with pseudowords compared to words, in that in this latter case lexical effects are supposed to influence attentional and perceptual processes. Accordingly, we found that for pseudowords only the two types of errors are differently affected by this manipulation and only omissions correlate with the severity of the disorder in visuo-spatial tasks